1.. SPDX-License-Identifier: GPL-2.0 2 3=================================================================== 4The Definitive KVM (Kernel-based Virtual Machine) API Documentation 5=================================================================== 6 71. General description 8====================== 9 10The kvm API is centered around different kinds of file descriptors 11and ioctls that can be issued to these file descriptors. An initial 12open("/dev/kvm") obtains a handle to the kvm subsystem; this handle 13can be used to issue system ioctls. A KVM_CREATE_VM ioctl on this 14handle will create a VM file descriptor which can be used to issue VM 15ioctls. A KVM_CREATE_VCPU or KVM_CREATE_DEVICE ioctl on a VM fd will 16create a virtual cpu or device and return a file descriptor pointing to 17the new resource. 18 19In other words, the kvm API is a set of ioctls that are issued to 20different kinds of file descriptor in order to control various aspects of 21a virtual machine. Depending on the file descriptor that accepts them, 22ioctls belong to the following classes: 23 24 - System ioctls: These query and set global attributes which affect the 25 whole kvm subsystem. In addition a system ioctl is used to create 26 virtual machines. 27 28 - VM ioctls: These query and set attributes that affect an entire virtual 29 machine, for example memory layout. In addition a VM ioctl is used to 30 create virtual cpus (vcpus) and devices. 31 32 VM ioctls must be issued from the same process (address space) that was 33 used to create the VM. 34 35 - vcpu ioctls: These query and set attributes that control the operation 36 of a single virtual cpu. 37 38 vcpu ioctls should be issued from the same thread that was used to create 39 the vcpu, except for asynchronous vcpu ioctl that are marked as such in 40 the documentation. Otherwise, the first ioctl after switching threads 41 could see a performance impact. 42 43 - device ioctls: These query and set attributes that control the operation 44 of a single device. 45 46 device ioctls must be issued from the same process (address space) that 47 was used to create the VM. 48 49While most ioctls are specific to one kind of file descriptor, in some 50cases the same ioctl can belong to more than one class. 51 52The KVM API grew over time. For this reason, KVM defines many constants 53of the form ``KVM_CAP_*``, each corresponding to a set of functionality 54provided by one or more ioctls. Availability of these "capabilities" can 55be checked with :ref:`KVM_CHECK_EXTENSION <KVM_CHECK_EXTENSION>`. Some 56capabilities also need to be enabled for VMs or VCPUs where their 57functionality is desired (see :ref:`cap_enable` and :ref:`cap_enable_vm`). 58 59 602. Restrictions 61=============== 62 63In general file descriptors can be migrated among processes by means 64of fork() and the SCM_RIGHTS facility of unix domain socket. These 65kinds of tricks are explicitly not supported by kvm. While they will 66not cause harm to the host, their actual behavior is not guaranteed by 67the API. See "General description" for details on the ioctl usage 68model that is supported by KVM. 69 70It is important to note that although VM ioctls may only be issued from 71the process that created the VM, a VM's lifecycle is associated with its 72file descriptor, not its creator (process). In other words, the VM and 73its resources, *including the associated address space*, are not freed 74until the last reference to the VM's file descriptor has been released. 75For example, if fork() is issued after ioctl(KVM_CREATE_VM), the VM will 76not be freed until both the parent (original) process and its child have 77put their references to the VM's file descriptor. 78 79Because a VM's resources are not freed until the last reference to its 80file descriptor is released, creating additional references to a VM 81via fork(), dup(), etc... without careful consideration is strongly 82discouraged and may have unwanted side effects, e.g. memory allocated 83by and on behalf of the VM's process may not be freed/unaccounted when 84the VM is shut down. 85 86 873. Extensions 88============= 89 90As of Linux 2.6.22, the KVM ABI has been stabilized: no backward 91incompatible change are allowed. However, there is an extension 92facility that allows backward-compatible extensions to the API to be 93queried and used. 94 95The extension mechanism is not based on the Linux version number. 96Instead, kvm defines extension identifiers and a facility to query 97whether a particular extension identifier is available. If it is, a 98set of ioctls is available for application use. 99 100 1014. API description 102================== 103 104This section describes ioctls that can be used to control kvm guests. 105For each ioctl, the following information is provided along with a 106description: 107 108 Capability: 109 which KVM extension provides this ioctl. Can be 'basic', 110 which means that is will be provided by any kernel that supports 111 API version 12 (see :ref:`KVM_GET_API_VERSION <KVM_GET_API_VERSION>`), 112 or a KVM_CAP_xyz constant that can be checked with 113 :ref:`KVM_CHECK_EXTENSION <KVM_CHECK_EXTENSION>`. 114 115 Architectures: 116 which instruction set architectures provide this ioctl. 117 x86 includes both i386 and x86_64. 118 119 Type: 120 system, vm, or vcpu. 121 122 Parameters: 123 what parameters are accepted by the ioctl. 124 125 Returns: 126 the return value. General error numbers (EBADF, ENOMEM, EINVAL) 127 are not detailed, but errors with specific meanings are. 128 129 130.. _KVM_GET_API_VERSION: 131 1324.1 KVM_GET_API_VERSION 133----------------------- 134 135:Capability: basic 136:Architectures: all 137:Type: system ioctl 138:Parameters: none 139:Returns: the constant KVM_API_VERSION (=12) 140 141This identifies the API version as the stable kvm API. It is not 142expected that this number will change. However, Linux 2.6.20 and 1432.6.21 report earlier versions; these are not documented and not 144supported. Applications should refuse to run if KVM_GET_API_VERSION 145returns a value other than 12. If this check passes, all ioctls 146described as 'basic' will be available. 147 148 1494.2 KVM_CREATE_VM 150----------------- 151 152:Capability: basic 153:Architectures: all 154:Type: system ioctl 155:Parameters: machine type identifier (KVM_VM_*) 156:Returns: a VM fd that can be used to control the new virtual machine. 157 158The new VM has no virtual cpus and no memory. 159You probably want to use 0 as machine type. 160 161X86: 162^^^^ 163 164Supported X86 VM types can be queried via KVM_CAP_VM_TYPES. 165 166S390: 167^^^^^ 168 169In order to create user controlled virtual machines on S390, check 170KVM_CAP_S390_UCONTROL and use the flag KVM_VM_S390_UCONTROL as 171privileged user (CAP_SYS_ADMIN). 172 173MIPS: 174^^^^^ 175 176To use hardware assisted virtualization on MIPS (VZ ASE) rather than 177the default trap & emulate implementation (which changes the virtual 178memory layout to fit in user mode), check KVM_CAP_MIPS_VZ and use the 179flag KVM_VM_MIPS_VZ. 180 181ARM64: 182^^^^^^ 183 184On arm64, the physical address size for a VM (IPA Size limit) is limited 185to 40bits by default. The limit can be configured if the host supports the 186extension KVM_CAP_ARM_VM_IPA_SIZE. When supported, use 187KVM_VM_TYPE_ARM_IPA_SIZE(IPA_Bits) to set the size in the machine type 188identifier, where IPA_Bits is the maximum width of any physical 189address used by the VM. The IPA_Bits is encoded in bits[7-0] of the 190machine type identifier. 191 192e.g, to configure a guest to use 48bit physical address size:: 193 194 vm_fd = ioctl(dev_fd, KVM_CREATE_VM, KVM_VM_TYPE_ARM_IPA_SIZE(48)); 195 196The requested size (IPA_Bits) must be: 197 198 == ========================================================= 199 0 Implies default size, 40bits (for backward compatibility) 200 N Implies N bits, where N is a positive integer such that, 201 32 <= N <= Host_IPA_Limit 202 == ========================================================= 203 204Host_IPA_Limit is the maximum possible value for IPA_Bits on the host and 205is dependent on the CPU capability and the kernel configuration. The limit can 206be retrieved using KVM_CAP_ARM_VM_IPA_SIZE of the KVM_CHECK_EXTENSION 207ioctl() at run-time. 208 209Creation of the VM will fail if the requested IPA size (whether it is 210implicit or explicit) is unsupported on the host. 211 212Please note that configuring the IPA size does not affect the capability 213exposed by the guest CPUs in ID_AA64MMFR0_EL1[PARange]. It only affects 214size of the address translated by the stage2 level (guest physical to 215host physical address translations). 216 217 2184.3 KVM_GET_MSR_INDEX_LIST, KVM_GET_MSR_FEATURE_INDEX_LIST 219---------------------------------------------------------- 220 221:Capability: basic, KVM_CAP_GET_MSR_FEATURES for KVM_GET_MSR_FEATURE_INDEX_LIST 222:Architectures: x86 223:Type: system ioctl 224:Parameters: struct kvm_msr_list (in/out) 225:Returns: 0 on success; -1 on error 226 227Errors: 228 229 ====== ============================================================ 230 EFAULT the msr index list cannot be read from or written to 231 E2BIG the msr index list is too big to fit in the array specified by 232 the user. 233 ====== ============================================================ 234 235:: 236 237 struct kvm_msr_list { 238 __u32 nmsrs; /* number of msrs in entries */ 239 __u32 indices[0]; 240 }; 241 242The user fills in the size of the indices array in nmsrs, and in return 243kvm adjusts nmsrs to reflect the actual number of msrs and fills in the 244indices array with their numbers. 245 246KVM_GET_MSR_INDEX_LIST returns the guest msrs that are supported. The list 247varies by kvm version and host processor, but does not change otherwise. 248 249Note: if kvm indicates supports MCE (KVM_CAP_MCE), then the MCE bank MSRs are 250not returned in the MSR list, as different vcpus can have a different number 251of banks, as set via the KVM_X86_SETUP_MCE ioctl. 252 253KVM_GET_MSR_FEATURE_INDEX_LIST returns the list of MSRs that can be passed 254to the KVM_GET_MSRS system ioctl. This lets userspace probe host capabilities 255and processor features that are exposed via MSRs (e.g., VMX capabilities). 256This list also varies by kvm version and host processor, but does not change 257otherwise. 258 259 260.. _KVM_CHECK_EXTENSION: 261 2624.4 KVM_CHECK_EXTENSION 263----------------------- 264 265:Capability: basic, KVM_CAP_CHECK_EXTENSION_VM for vm ioctl 266:Architectures: all 267:Type: system ioctl, vm ioctl 268:Parameters: extension identifier (KVM_CAP_*) 269:Returns: 0 if unsupported; 1 (or some other positive integer) if supported 270 271The API allows the application to query about extensions to the core 272kvm API. Userspace passes an extension identifier (an integer) and 273receives an integer that describes the extension availability. 274Generally 0 means no and 1 means yes, but some extensions may report 275additional information in the integer return value. 276 277Based on their initialization different VMs may have different capabilities. 278It is thus encouraged to use the vm ioctl to query for capabilities (available 279with KVM_CAP_CHECK_EXTENSION_VM on the vm fd) 280 2814.5 KVM_GET_VCPU_MMAP_SIZE 282-------------------------- 283 284:Capability: basic 285:Architectures: all 286:Type: system ioctl 287:Parameters: none 288:Returns: size of vcpu mmap area, in bytes 289 290The KVM_RUN ioctl (cf.) communicates with userspace via a shared 291memory region. This ioctl returns the size of that region. See the 292KVM_RUN documentation for details. 293 294Besides the size of the KVM_RUN communication region, other areas of 295the VCPU file descriptor can be mmap-ed, including: 296 297- if KVM_CAP_COALESCED_MMIO is available, a page at 298 KVM_COALESCED_MMIO_PAGE_OFFSET * PAGE_SIZE; for historical reasons, 299 this page is included in the result of KVM_GET_VCPU_MMAP_SIZE. 300 KVM_CAP_COALESCED_MMIO is not documented yet. 301 302- if KVM_CAP_DIRTY_LOG_RING is available, a number of pages at 303 KVM_DIRTY_LOG_PAGE_OFFSET * PAGE_SIZE. For more information on 304 KVM_CAP_DIRTY_LOG_RING, see :ref:`KVM_CAP_DIRTY_LOG_RING`. 305 306 3074.7 KVM_CREATE_VCPU 308------------------- 309 310:Capability: basic 311:Architectures: all 312:Type: vm ioctl 313:Parameters: vcpu id (apic id on x86) 314:Returns: vcpu fd on success, -1 on error 315 316This API adds a vcpu to a virtual machine. No more than max_vcpus may be added. 317The vcpu id is an integer in the range [0, max_vcpu_id). 318 319The recommended max_vcpus value can be retrieved using the KVM_CAP_NR_VCPUS of 320the KVM_CHECK_EXTENSION ioctl() at run-time. 321The maximum possible value for max_vcpus can be retrieved using the 322KVM_CAP_MAX_VCPUS of the KVM_CHECK_EXTENSION ioctl() at run-time. 323 324If the KVM_CAP_NR_VCPUS does not exist, you should assume that max_vcpus is 4 325cpus max. 326If the KVM_CAP_MAX_VCPUS does not exist, you should assume that max_vcpus is 327same as the value returned from KVM_CAP_NR_VCPUS. 328 329The maximum possible value for max_vcpu_id can be retrieved using the 330KVM_CAP_MAX_VCPU_ID of the KVM_CHECK_EXTENSION ioctl() at run-time. 331 332If the KVM_CAP_MAX_VCPU_ID does not exist, you should assume that max_vcpu_id 333is the same as the value returned from KVM_CAP_MAX_VCPUS. 334 335On powerpc using book3s_hv mode, the vcpus are mapped onto virtual 336threads in one or more virtual CPU cores. (This is because the 337hardware requires all the hardware threads in a CPU core to be in the 338same partition.) The KVM_CAP_PPC_SMT capability indicates the number 339of vcpus per virtual core (vcore). The vcore id is obtained by 340dividing the vcpu id by the number of vcpus per vcore. The vcpus in a 341given vcore will always be in the same physical core as each other 342(though that might be a different physical core from time to time). 343Userspace can control the threading (SMT) mode of the guest by its 344allocation of vcpu ids. For example, if userspace wants 345single-threaded guest vcpus, it should make all vcpu ids be a multiple 346of the number of vcpus per vcore. 347 348For virtual cpus that have been created with S390 user controlled virtual 349machines, the resulting vcpu fd can be memory mapped at page offset 350KVM_S390_SIE_PAGE_OFFSET in order to obtain a memory map of the virtual 351cpu's hardware control block. 352 353 3544.8 KVM_GET_DIRTY_LOG 355--------------------- 356 357:Capability: basic 358:Architectures: all 359:Type: vm ioctl 360:Parameters: struct kvm_dirty_log (in/out) 361:Returns: 0 on success, -1 on error 362 363:: 364 365 /* for KVM_GET_DIRTY_LOG */ 366 struct kvm_dirty_log { 367 __u32 slot; 368 __u32 padding; 369 union { 370 void __user *dirty_bitmap; /* one bit per page */ 371 __u64 padding; 372 }; 373 }; 374 375Given a memory slot, return a bitmap containing any pages dirtied 376since the last call to this ioctl. Bit 0 is the first page in the 377memory slot. Ensure the entire structure is cleared to avoid padding 378issues. 379 380If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 of slot field specifies 381the address space for which you want to return the dirty bitmap. See 382KVM_SET_USER_MEMORY_REGION for details on the usage of slot field. 383 384The bits in the dirty bitmap are cleared before the ioctl returns, unless 385KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is enabled. For more information, 386see the description of the capability. 387 388Note that the Xen shared_info page, if configured, shall always be assumed 389to be dirty. KVM will not explicitly mark it such. 390 391 3924.10 KVM_RUN 393------------ 394 395:Capability: basic 396:Architectures: all 397:Type: vcpu ioctl 398:Parameters: none 399:Returns: 0 on success, -1 on error 400 401Errors: 402 403 ======= ============================================================== 404 EINTR an unmasked signal is pending 405 ENOEXEC the vcpu hasn't been initialized or the guest tried to execute 406 instructions from device memory (arm64) 407 ENOSYS data abort outside memslots with no syndrome info and 408 KVM_CAP_ARM_NISV_TO_USER not enabled (arm64) 409 EPERM SVE feature set but not finalized (arm64) 410 ======= ============================================================== 411 412This ioctl is used to run a guest virtual cpu. While there are no 413explicit parameters, there is an implicit parameter block that can be 414obtained by mmap()ing the vcpu fd at offset 0, with the size given by 415KVM_GET_VCPU_MMAP_SIZE. The parameter block is formatted as a 'struct 416kvm_run' (see below). 417 418 4194.11 KVM_GET_REGS 420----------------- 421 422:Capability: basic 423:Architectures: all except arm64 424:Type: vcpu ioctl 425:Parameters: struct kvm_regs (out) 426:Returns: 0 on success, -1 on error 427 428Reads the general purpose registers from the vcpu. 429 430:: 431 432 /* x86 */ 433 struct kvm_regs { 434 /* out (KVM_GET_REGS) / in (KVM_SET_REGS) */ 435 __u64 rax, rbx, rcx, rdx; 436 __u64 rsi, rdi, rsp, rbp; 437 __u64 r8, r9, r10, r11; 438 __u64 r12, r13, r14, r15; 439 __u64 rip, rflags; 440 }; 441 442 /* mips */ 443 struct kvm_regs { 444 /* out (KVM_GET_REGS) / in (KVM_SET_REGS) */ 445 __u64 gpr[32]; 446 __u64 hi; 447 __u64 lo; 448 __u64 pc; 449 }; 450 451 /* LoongArch */ 452 struct kvm_regs { 453 /* out (KVM_GET_REGS) / in (KVM_SET_REGS) */ 454 unsigned long gpr[32]; 455 unsigned long pc; 456 }; 457 458 4594.12 KVM_SET_REGS 460----------------- 461 462:Capability: basic 463:Architectures: all except arm64 464:Type: vcpu ioctl 465:Parameters: struct kvm_regs (in) 466:Returns: 0 on success, -1 on error 467 468Writes the general purpose registers into the vcpu. 469 470See KVM_GET_REGS for the data structure. 471 472 4734.13 KVM_GET_SREGS 474------------------ 475 476:Capability: basic 477:Architectures: x86, ppc 478:Type: vcpu ioctl 479:Parameters: struct kvm_sregs (out) 480:Returns: 0 on success, -1 on error 481 482Reads special registers from the vcpu. 483 484:: 485 486 /* x86 */ 487 struct kvm_sregs { 488 struct kvm_segment cs, ds, es, fs, gs, ss; 489 struct kvm_segment tr, ldt; 490 struct kvm_dtable gdt, idt; 491 __u64 cr0, cr2, cr3, cr4, cr8; 492 __u64 efer; 493 __u64 apic_base; 494 __u64 interrupt_bitmap[(KVM_NR_INTERRUPTS + 63) / 64]; 495 }; 496 497 /* ppc -- see arch/powerpc/include/uapi/asm/kvm.h */ 498 499interrupt_bitmap is a bitmap of pending external interrupts. At most 500one bit may be set. This interrupt has been acknowledged by the APIC 501but not yet injected into the cpu core. 502 503 5044.14 KVM_SET_SREGS 505------------------ 506 507:Capability: basic 508:Architectures: x86, ppc 509:Type: vcpu ioctl 510:Parameters: struct kvm_sregs (in) 511:Returns: 0 on success, -1 on error 512 513Writes special registers into the vcpu. See KVM_GET_SREGS for the 514data structures. 515 516 5174.15 KVM_TRANSLATE 518------------------ 519 520:Capability: basic 521:Architectures: x86 522:Type: vcpu ioctl 523:Parameters: struct kvm_translation (in/out) 524:Returns: 0 on success, -1 on error 525 526Translates a virtual address according to the vcpu's current address 527translation mode. 528 529:: 530 531 struct kvm_translation { 532 /* in */ 533 __u64 linear_address; 534 535 /* out */ 536 __u64 physical_address; 537 __u8 valid; 538 __u8 writeable; 539 __u8 usermode; 540 __u8 pad[5]; 541 }; 542 543 5444.16 KVM_INTERRUPT 545------------------ 546 547:Capability: basic 548:Architectures: x86, ppc, mips, riscv, loongarch 549:Type: vcpu ioctl 550:Parameters: struct kvm_interrupt (in) 551:Returns: 0 on success, negative on failure. 552 553Queues a hardware interrupt vector to be injected. 554 555:: 556 557 /* for KVM_INTERRUPT */ 558 struct kvm_interrupt { 559 /* in */ 560 __u32 irq; 561 }; 562 563X86: 564^^^^ 565 566:Returns: 567 568 ========= =================================== 569 0 on success, 570 -EEXIST if an interrupt is already enqueued 571 -EINVAL the irq number is invalid 572 -ENXIO if the PIC is in the kernel 573 -EFAULT if the pointer is invalid 574 ========= =================================== 575 576Note 'irq' is an interrupt vector, not an interrupt pin or line. This 577ioctl is useful if the in-kernel PIC is not used. 578 579PPC: 580^^^^ 581 582Queues an external interrupt to be injected. This ioctl is overloaded 583with 3 different irq values: 584 585a) KVM_INTERRUPT_SET 586 587 This injects an edge type external interrupt into the guest once it's ready 588 to receive interrupts. When injected, the interrupt is done. 589 590b) KVM_INTERRUPT_UNSET 591 592 This unsets any pending interrupt. 593 594 Only available with KVM_CAP_PPC_UNSET_IRQ. 595 596c) KVM_INTERRUPT_SET_LEVEL 597 598 This injects a level type external interrupt into the guest context. The 599 interrupt stays pending until a specific ioctl with KVM_INTERRUPT_UNSET 600 is triggered. 601 602 Only available with KVM_CAP_PPC_IRQ_LEVEL. 603 604Note that any value for 'irq' other than the ones stated above is invalid 605and incurs unexpected behavior. 606 607This is an asynchronous vcpu ioctl and can be invoked from any thread. 608 609MIPS: 610^^^^^ 611 612Queues an external interrupt to be injected into the virtual CPU. A negative 613interrupt number dequeues the interrupt. 614 615This is an asynchronous vcpu ioctl and can be invoked from any thread. 616 617RISC-V: 618^^^^^^^ 619 620Queues an external interrupt to be injected into the virtual CPU. This ioctl 621is overloaded with 2 different irq values: 622 623a) KVM_INTERRUPT_SET 624 625 This sets external interrupt for a virtual CPU and it will receive 626 once it is ready. 627 628b) KVM_INTERRUPT_UNSET 629 630 This clears pending external interrupt for a virtual CPU. 631 632This is an asynchronous vcpu ioctl and can be invoked from any thread. 633 634LOONGARCH: 635^^^^^^^^^^ 636 637Queues an external interrupt to be injected into the virtual CPU. A negative 638interrupt number dequeues the interrupt. 639 640This is an asynchronous vcpu ioctl and can be invoked from any thread. 641 642 6434.18 KVM_GET_MSRS 644----------------- 645 646:Capability: basic (vcpu), KVM_CAP_GET_MSR_FEATURES (system) 647:Architectures: x86 648:Type: system ioctl, vcpu ioctl 649:Parameters: struct kvm_msrs (in/out) 650:Returns: number of msrs successfully returned; 651 -1 on error 652 653When used as a system ioctl: 654Reads the values of MSR-based features that are available for the VM. This 655is similar to KVM_GET_SUPPORTED_CPUID, but it returns MSR indices and values. 656The list of msr-based features can be obtained using KVM_GET_MSR_FEATURE_INDEX_LIST 657in a system ioctl. 658 659When used as a vcpu ioctl: 660Reads model-specific registers from the vcpu. Supported msr indices can 661be obtained using KVM_GET_MSR_INDEX_LIST in a system ioctl. 662 663:: 664 665 struct kvm_msrs { 666 __u32 nmsrs; /* number of msrs in entries */ 667 __u32 pad; 668 669 struct kvm_msr_entry entries[0]; 670 }; 671 672 struct kvm_msr_entry { 673 __u32 index; 674 __u32 reserved; 675 __u64 data; 676 }; 677 678Application code should set the 'nmsrs' member (which indicates the 679size of the entries array) and the 'index' member of each array entry. 680kvm will fill in the 'data' member. 681 682 6834.19 KVM_SET_MSRS 684----------------- 685 686:Capability: basic 687:Architectures: x86 688:Type: vcpu ioctl 689:Parameters: struct kvm_msrs (in) 690:Returns: number of msrs successfully set (see below), -1 on error 691 692Writes model-specific registers to the vcpu. See KVM_GET_MSRS for the 693data structures. 694 695Application code should set the 'nmsrs' member (which indicates the 696size of the entries array), and the 'index' and 'data' members of each 697array entry. 698 699It tries to set the MSRs in array entries[] one by one. If setting an MSR 700fails, e.g., due to setting reserved bits, the MSR isn't supported/emulated 701by KVM, etc..., it stops processing the MSR list and returns the number of 702MSRs that have been set successfully. 703 704 7054.20 KVM_SET_CPUID 706------------------ 707 708:Capability: basic 709:Architectures: x86 710:Type: vcpu ioctl 711:Parameters: struct kvm_cpuid (in) 712:Returns: 0 on success, -1 on error 713 714Defines the vcpu responses to the cpuid instruction. Applications 715should use the KVM_SET_CPUID2 ioctl if available. 716 717Caveat emptor: 718 - If this IOCTL fails, KVM gives no guarantees that previous valid CPUID 719 configuration (if there is) is not corrupted. Userspace can get a copy 720 of the resulting CPUID configuration through KVM_GET_CPUID2 in case. 721 - Using KVM_SET_CPUID{,2} after KVM_RUN, i.e. changing the guest vCPU model 722 after running the guest, may cause guest instability. 723 - Using heterogeneous CPUID configurations, modulo APIC IDs, topology, etc... 724 may cause guest instability. 725 726:: 727 728 struct kvm_cpuid_entry { 729 __u32 function; 730 __u32 eax; 731 __u32 ebx; 732 __u32 ecx; 733 __u32 edx; 734 __u32 padding; 735 }; 736 737 /* for KVM_SET_CPUID */ 738 struct kvm_cpuid { 739 __u32 nent; 740 __u32 padding; 741 struct kvm_cpuid_entry entries[0]; 742 }; 743 744 7454.21 KVM_SET_SIGNAL_MASK 746------------------------ 747 748:Capability: basic 749:Architectures: all 750:Type: vcpu ioctl 751:Parameters: struct kvm_signal_mask (in) 752:Returns: 0 on success, -1 on error 753 754Defines which signals are blocked during execution of KVM_RUN. This 755signal mask temporarily overrides the threads signal mask. Any 756unblocked signal received (except SIGKILL and SIGSTOP, which retain 757their traditional behaviour) will cause KVM_RUN to return with -EINTR. 758 759Note the signal will only be delivered if not blocked by the original 760signal mask. 761 762:: 763 764 /* for KVM_SET_SIGNAL_MASK */ 765 struct kvm_signal_mask { 766 __u32 len; 767 __u8 sigset[0]; 768 }; 769 770 7714.22 KVM_GET_FPU 772---------------- 773 774:Capability: basic 775:Architectures: x86, loongarch 776:Type: vcpu ioctl 777:Parameters: struct kvm_fpu (out) 778:Returns: 0 on success, -1 on error 779 780Reads the floating point state from the vcpu. 781 782:: 783 784 /* x86: for KVM_GET_FPU and KVM_SET_FPU */ 785 struct kvm_fpu { 786 __u8 fpr[8][16]; 787 __u16 fcw; 788 __u16 fsw; 789 __u8 ftwx; /* in fxsave format */ 790 __u8 pad1; 791 __u16 last_opcode; 792 __u64 last_ip; 793 __u64 last_dp; 794 __u8 xmm[16][16]; 795 __u32 mxcsr; 796 __u32 pad2; 797 }; 798 799 /* LoongArch: for KVM_GET_FPU and KVM_SET_FPU */ 800 struct kvm_fpu { 801 __u32 fcsr; 802 __u64 fcc; 803 struct kvm_fpureg { 804 __u64 val64[4]; 805 }fpr[32]; 806 }; 807 808 8094.23 KVM_SET_FPU 810---------------- 811 812:Capability: basic 813:Architectures: x86, loongarch 814:Type: vcpu ioctl 815:Parameters: struct kvm_fpu (in) 816:Returns: 0 on success, -1 on error 817 818Writes the floating point state to the vcpu. 819 820:: 821 822 /* x86: for KVM_GET_FPU and KVM_SET_FPU */ 823 struct kvm_fpu { 824 __u8 fpr[8][16]; 825 __u16 fcw; 826 __u16 fsw; 827 __u8 ftwx; /* in fxsave format */ 828 __u8 pad1; 829 __u16 last_opcode; 830 __u64 last_ip; 831 __u64 last_dp; 832 __u8 xmm[16][16]; 833 __u32 mxcsr; 834 __u32 pad2; 835 }; 836 837 /* LoongArch: for KVM_GET_FPU and KVM_SET_FPU */ 838 struct kvm_fpu { 839 __u32 fcsr; 840 __u64 fcc; 841 struct kvm_fpureg { 842 __u64 val64[4]; 843 }fpr[32]; 844 }; 845 846 8474.24 KVM_CREATE_IRQCHIP 848----------------------- 849 850:Capability: KVM_CAP_IRQCHIP, KVM_CAP_S390_IRQCHIP (s390) 851:Architectures: x86, arm64, s390 852:Type: vm ioctl 853:Parameters: none 854:Returns: 0 on success, -1 on error 855 856Creates an interrupt controller model in the kernel. 857On x86, creates a virtual ioapic, a virtual PIC (two PICs, nested), and sets up 858future vcpus to have a local APIC. IRQ routing for GSIs 0-15 is set to both 859PIC and IOAPIC; GSI 16-23 only go to the IOAPIC. 860On arm64, a GICv2 is created. Any other GIC versions require the usage of 861KVM_CREATE_DEVICE, which also supports creating a GICv2. Using 862KVM_CREATE_DEVICE is preferred over KVM_CREATE_IRQCHIP for GICv2. 863On s390, a dummy irq routing table is created. 864 865Note that on s390 the KVM_CAP_S390_IRQCHIP vm capability needs to be enabled 866before KVM_CREATE_IRQCHIP can be used. 867 868 8694.25 KVM_IRQ_LINE 870----------------- 871 872:Capability: KVM_CAP_IRQCHIP 873:Architectures: x86, arm64 874:Type: vm ioctl 875:Parameters: struct kvm_irq_level 876:Returns: 0 on success, -1 on error 877 878Sets the level of a GSI input to the interrupt controller model in the kernel. 879On some architectures it is required that an interrupt controller model has 880been previously created with KVM_CREATE_IRQCHIP. Note that edge-triggered 881interrupts require the level to be set to 1 and then back to 0. 882 883On real hardware, interrupt pins can be active-low or active-high. This 884does not matter for the level field of struct kvm_irq_level: 1 always 885means active (asserted), 0 means inactive (deasserted). 886 887x86 allows the operating system to program the interrupt polarity 888(active-low/active-high) for level-triggered interrupts, and KVM used 889to consider the polarity. However, due to bitrot in the handling of 890active-low interrupts, the above convention is now valid on x86 too. 891This is signaled by KVM_CAP_X86_IOAPIC_POLARITY_IGNORED. Userspace 892should not present interrupts to the guest as active-low unless this 893capability is present (or unless it is not using the in-kernel irqchip, 894of course). 895 896 897arm64 can signal an interrupt either at the CPU level, or at the 898in-kernel irqchip (GIC), and for in-kernel irqchip can tell the GIC to 899use PPIs designated for specific cpus. The irq field is interpreted 900like this:: 901 902 bits: | 31 ... 28 | 27 ... 24 | 23 ... 16 | 15 ... 0 | 903 field: | vcpu2_index | irq_type | vcpu_index | irq_id | 904 905The irq_type field has the following values: 906 907- KVM_ARM_IRQ_TYPE_CPU: 908 out-of-kernel GIC: irq_id 0 is IRQ, irq_id 1 is FIQ 909- KVM_ARM_IRQ_TYPE_SPI: 910 in-kernel GIC: SPI, irq_id between 32 and 1019 (incl.) 911 (the vcpu_index field is ignored) 912- KVM_ARM_IRQ_TYPE_PPI: 913 in-kernel GIC: PPI, irq_id between 16 and 31 (incl.) 914 915(The irq_id field thus corresponds nicely to the IRQ ID in the ARM GIC specs) 916 917In both cases, level is used to assert/deassert the line. 918 919When KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 is supported, the target vcpu is 920identified as (256 * vcpu2_index + vcpu_index). Otherwise, vcpu2_index 921must be zero. 922 923Note that on arm64, the KVM_CAP_IRQCHIP capability only conditions 924injection of interrupts for the in-kernel irqchip. KVM_IRQ_LINE can always 925be used for a userspace interrupt controller. 926 927:: 928 929 struct kvm_irq_level { 930 union { 931 __u32 irq; /* GSI */ 932 __s32 status; /* not used for KVM_IRQ_LEVEL */ 933 }; 934 __u32 level; /* 0 or 1 */ 935 }; 936 937 9384.26 KVM_GET_IRQCHIP 939-------------------- 940 941:Capability: KVM_CAP_IRQCHIP 942:Architectures: x86 943:Type: vm ioctl 944:Parameters: struct kvm_irqchip (in/out) 945:Returns: 0 on success, -1 on error 946 947Reads the state of a kernel interrupt controller created with 948KVM_CREATE_IRQCHIP into a buffer provided by the caller. 949 950:: 951 952 struct kvm_irqchip { 953 __u32 chip_id; /* 0 = PIC1, 1 = PIC2, 2 = IOAPIC */ 954 __u32 pad; 955 union { 956 char dummy[512]; /* reserving space */ 957 struct kvm_pic_state pic; 958 struct kvm_ioapic_state ioapic; 959 } chip; 960 }; 961 962 9634.27 KVM_SET_IRQCHIP 964-------------------- 965 966:Capability: KVM_CAP_IRQCHIP 967:Architectures: x86 968:Type: vm ioctl 969:Parameters: struct kvm_irqchip (in) 970:Returns: 0 on success, -1 on error 971 972Sets the state of a kernel interrupt controller created with 973KVM_CREATE_IRQCHIP from a buffer provided by the caller. 974 975:: 976 977 struct kvm_irqchip { 978 __u32 chip_id; /* 0 = PIC1, 1 = PIC2, 2 = IOAPIC */ 979 __u32 pad; 980 union { 981 char dummy[512]; /* reserving space */ 982 struct kvm_pic_state pic; 983 struct kvm_ioapic_state ioapic; 984 } chip; 985 }; 986 987 9884.28 KVM_XEN_HVM_CONFIG 989----------------------- 990 991:Capability: KVM_CAP_XEN_HVM 992:Architectures: x86 993:Type: vm ioctl 994:Parameters: struct kvm_xen_hvm_config (in) 995:Returns: 0 on success, -1 on error 996 997Sets the MSR that the Xen HVM guest uses to initialize its hypercall 998page, and provides the starting address and size of the hypercall 999blobs in userspace. When the guest writes the MSR, kvm copies one 1000page of a blob (32- or 64-bit, depending on the vcpu mode) to guest 1001memory. 1002 1003The MSR index must be in the range [0x40000000, 0x4fffffff], i.e. must reside 1004in the range that is unofficially reserved for use by hypervisors. The min/max 1005values are enumerated via KVM_XEN_MSR_MIN_INDEX and KVM_XEN_MSR_MAX_INDEX. 1006 1007:: 1008 1009 struct kvm_xen_hvm_config { 1010 __u32 flags; 1011 __u32 msr; 1012 __u64 blob_addr_32; 1013 __u64 blob_addr_64; 1014 __u8 blob_size_32; 1015 __u8 blob_size_64; 1016 __u8 pad2[30]; 1017 }; 1018 1019If certain flags are returned from the KVM_CAP_XEN_HVM check, they may 1020be set in the flags field of this ioctl: 1021 1022The KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL flag requests KVM to generate 1023the contents of the hypercall page automatically; hypercalls will be 1024intercepted and passed to userspace through KVM_EXIT_XEN. In this 1025case, all of the blob size and address fields must be zero. 1026 1027The KVM_XEN_HVM_CONFIG_EVTCHN_SEND flag indicates to KVM that userspace 1028will always use the KVM_XEN_HVM_EVTCHN_SEND ioctl to deliver event 1029channel interrupts rather than manipulating the guest's shared_info 1030structures directly. This, in turn, may allow KVM to enable features 1031such as intercepting the SCHEDOP_poll hypercall to accelerate PV 1032spinlock operation for the guest. Userspace may still use the ioctl 1033to deliver events if it was advertised, even if userspace does not 1034send this indication that it will always do so 1035 1036No other flags are currently valid in the struct kvm_xen_hvm_config. 1037 10384.29 KVM_GET_CLOCK 1039------------------ 1040 1041:Capability: KVM_CAP_ADJUST_CLOCK 1042:Architectures: x86 1043:Type: vm ioctl 1044:Parameters: struct kvm_clock_data (out) 1045:Returns: 0 on success, -1 on error 1046 1047Gets the current timestamp of kvmclock as seen by the current guest. In 1048conjunction with KVM_SET_CLOCK, it is used to ensure monotonicity on scenarios 1049such as migration. 1050 1051When KVM_CAP_ADJUST_CLOCK is passed to KVM_CHECK_EXTENSION, it returns the 1052set of bits that KVM can return in struct kvm_clock_data's flag member. 1053 1054The following flags are defined: 1055 1056KVM_CLOCK_TSC_STABLE 1057 If set, the returned value is the exact kvmclock 1058 value seen by all VCPUs at the instant when KVM_GET_CLOCK was called. 1059 If clear, the returned value is simply CLOCK_MONOTONIC plus a constant 1060 offset; the offset can be modified with KVM_SET_CLOCK. KVM will try 1061 to make all VCPUs follow this clock, but the exact value read by each 1062 VCPU could differ, because the host TSC is not stable. 1063 1064KVM_CLOCK_REALTIME 1065 If set, the `realtime` field in the kvm_clock_data 1066 structure is populated with the value of the host's real time 1067 clocksource at the instant when KVM_GET_CLOCK was called. If clear, 1068 the `realtime` field does not contain a value. 1069 1070KVM_CLOCK_HOST_TSC 1071 If set, the `host_tsc` field in the kvm_clock_data 1072 structure is populated with the value of the host's timestamp counter (TSC) 1073 at the instant when KVM_GET_CLOCK was called. If clear, the `host_tsc` field 1074 does not contain a value. 1075 1076:: 1077 1078 struct kvm_clock_data { 1079 __u64 clock; /* kvmclock current value */ 1080 __u32 flags; 1081 __u32 pad0; 1082 __u64 realtime; 1083 __u64 host_tsc; 1084 __u32 pad[4]; 1085 }; 1086 1087 10884.30 KVM_SET_CLOCK 1089------------------ 1090 1091:Capability: KVM_CAP_ADJUST_CLOCK 1092:Architectures: x86 1093:Type: vm ioctl 1094:Parameters: struct kvm_clock_data (in) 1095:Returns: 0 on success, -1 on error 1096 1097Sets the current timestamp of kvmclock to the value specified in its parameter. 1098In conjunction with KVM_GET_CLOCK, it is used to ensure monotonicity on scenarios 1099such as migration. 1100 1101The following flags can be passed: 1102 1103KVM_CLOCK_REALTIME 1104 If set, KVM will compare the value of the `realtime` field 1105 with the value of the host's real time clocksource at the instant when 1106 KVM_SET_CLOCK was called. The difference in elapsed time is added to the final 1107 kvmclock value that will be provided to guests. 1108 1109Other flags returned by ``KVM_GET_CLOCK`` are accepted but ignored. 1110 1111:: 1112 1113 struct kvm_clock_data { 1114 __u64 clock; /* kvmclock current value */ 1115 __u32 flags; 1116 __u32 pad0; 1117 __u64 realtime; 1118 __u64 host_tsc; 1119 __u32 pad[4]; 1120 }; 1121 1122 11234.31 KVM_GET_VCPU_EVENTS 1124------------------------ 1125 1126:Capability: KVM_CAP_VCPU_EVENTS 1127:Extended by: KVM_CAP_INTR_SHADOW 1128:Architectures: x86, arm64 1129:Type: vcpu ioctl 1130:Parameters: struct kvm_vcpu_events (out) 1131:Returns: 0 on success, -1 on error 1132 1133X86: 1134^^^^ 1135 1136Gets currently pending exceptions, interrupts, and NMIs as well as related 1137states of the vcpu. 1138 1139:: 1140 1141 struct kvm_vcpu_events { 1142 struct { 1143 __u8 injected; 1144 __u8 nr; 1145 __u8 has_error_code; 1146 __u8 pending; 1147 __u32 error_code; 1148 } exception; 1149 struct { 1150 __u8 injected; 1151 __u8 nr; 1152 __u8 soft; 1153 __u8 shadow; 1154 } interrupt; 1155 struct { 1156 __u8 injected; 1157 __u8 pending; 1158 __u8 masked; 1159 __u8 pad; 1160 } nmi; 1161 __u32 sipi_vector; 1162 __u32 flags; 1163 struct { 1164 __u8 smm; 1165 __u8 pending; 1166 __u8 smm_inside_nmi; 1167 __u8 latched_init; 1168 } smi; 1169 __u8 reserved[27]; 1170 __u8 exception_has_payload; 1171 __u64 exception_payload; 1172 }; 1173 1174The following bits are defined in the flags field: 1175 1176- KVM_VCPUEVENT_VALID_SHADOW may be set to signal that 1177 interrupt.shadow contains a valid state. 1178 1179- KVM_VCPUEVENT_VALID_SMM may be set to signal that smi contains a 1180 valid state. 1181 1182- KVM_VCPUEVENT_VALID_PAYLOAD may be set to signal that the 1183 exception_has_payload, exception_payload, and exception.pending 1184 fields contain a valid state. This bit will be set whenever 1185 KVM_CAP_EXCEPTION_PAYLOAD is enabled. 1186 1187- KVM_VCPUEVENT_VALID_TRIPLE_FAULT may be set to signal that the 1188 triple_fault_pending field contains a valid state. This bit will 1189 be set whenever KVM_CAP_X86_TRIPLE_FAULT_EVENT is enabled. 1190 1191ARM64: 1192^^^^^^ 1193 1194If the guest accesses a device that is being emulated by the host kernel in 1195such a way that a real device would generate a physical SError, KVM may make 1196a virtual SError pending for that VCPU. This system error interrupt remains 1197pending until the guest takes the exception by unmasking PSTATE.A. 1198 1199Running the VCPU may cause it to take a pending SError, or make an access that 1200causes an SError to become pending. The event's description is only valid while 1201the VPCU is not running. 1202 1203This API provides a way to read and write the pending 'event' state that is not 1204visible to the guest. To save, restore or migrate a VCPU the struct representing 1205the state can be read then written using this GET/SET API, along with the other 1206guest-visible registers. It is not possible to 'cancel' an SError that has been 1207made pending. 1208 1209A device being emulated in user-space may also wish to generate an SError. To do 1210this the events structure can be populated by user-space. The current state 1211should be read first, to ensure no existing SError is pending. If an existing 1212SError is pending, the architecture's 'Multiple SError interrupts' rules should 1213be followed. (2.5.3 of DDI0587.a "ARM Reliability, Availability, and 1214Serviceability (RAS) Specification"). 1215 1216SError exceptions always have an ESR value. Some CPUs have the ability to 1217specify what the virtual SError's ESR value should be. These systems will 1218advertise KVM_CAP_ARM_INJECT_SERROR_ESR. In this case exception.has_esr will 1219always have a non-zero value when read, and the agent making an SError pending 1220should specify the ISS field in the lower 24 bits of exception.serror_esr. If 1221the system supports KVM_CAP_ARM_INJECT_SERROR_ESR, but user-space sets the events 1222with exception.has_esr as zero, KVM will choose an ESR. 1223 1224Specifying exception.has_esr on a system that does not support it will return 1225-EINVAL. Setting anything other than the lower 24bits of exception.serror_esr 1226will return -EINVAL. 1227 1228It is not possible to read back a pending external abort (injected via 1229KVM_SET_VCPU_EVENTS or otherwise) because such an exception is always delivered 1230directly to the virtual CPU). 1231 1232Calling this ioctl on a vCPU that hasn't been initialized will return 1233-ENOEXEC. 1234 1235:: 1236 1237 struct kvm_vcpu_events { 1238 struct { 1239 __u8 serror_pending; 1240 __u8 serror_has_esr; 1241 __u8 ext_dabt_pending; 1242 /* Align it to 8 bytes */ 1243 __u8 pad[5]; 1244 __u64 serror_esr; 1245 } exception; 1246 __u32 reserved[12]; 1247 }; 1248 12494.32 KVM_SET_VCPU_EVENTS 1250------------------------ 1251 1252:Capability: KVM_CAP_VCPU_EVENTS 1253:Extended by: KVM_CAP_INTR_SHADOW 1254:Architectures: x86, arm64 1255:Type: vcpu ioctl 1256:Parameters: struct kvm_vcpu_events (in) 1257:Returns: 0 on success, -1 on error 1258 1259X86: 1260^^^^ 1261 1262Set pending exceptions, interrupts, and NMIs as well as related states of the 1263vcpu. 1264 1265See KVM_GET_VCPU_EVENTS for the data structure. 1266 1267Fields that may be modified asynchronously by running VCPUs can be excluded 1268from the update. These fields are nmi.pending, sipi_vector, smi.smm, 1269smi.pending. Keep the corresponding bits in the flags field cleared to 1270suppress overwriting the current in-kernel state. The bits are: 1271 1272=============================== ================================== 1273KVM_VCPUEVENT_VALID_NMI_PENDING transfer nmi.pending to the kernel 1274KVM_VCPUEVENT_VALID_SIPI_VECTOR transfer sipi_vector 1275KVM_VCPUEVENT_VALID_SMM transfer the smi sub-struct. 1276=============================== ================================== 1277 1278If KVM_CAP_INTR_SHADOW is available, KVM_VCPUEVENT_VALID_SHADOW can be set in 1279the flags field to signal that interrupt.shadow contains a valid state and 1280shall be written into the VCPU. 1281 1282KVM_VCPUEVENT_VALID_SMM can only be set if KVM_CAP_X86_SMM is available. 1283 1284If KVM_CAP_EXCEPTION_PAYLOAD is enabled, KVM_VCPUEVENT_VALID_PAYLOAD 1285can be set in the flags field to signal that the 1286exception_has_payload, exception_payload, and exception.pending fields 1287contain a valid state and shall be written into the VCPU. 1288 1289If KVM_CAP_X86_TRIPLE_FAULT_EVENT is enabled, KVM_VCPUEVENT_VALID_TRIPLE_FAULT 1290can be set in flags field to signal that the triple_fault field contains 1291a valid state and shall be written into the VCPU. 1292 1293ARM64: 1294^^^^^^ 1295 1296User space may need to inject several types of events to the guest. 1297 1298Set the pending SError exception state for this VCPU. It is not possible to 1299'cancel' an Serror that has been made pending. 1300 1301If the guest performed an access to I/O memory which could not be handled by 1302userspace, for example because of missing instruction syndrome decode 1303information or because there is no device mapped at the accessed IPA, then 1304userspace can ask the kernel to inject an external abort using the address 1305from the exiting fault on the VCPU. It is a programming error to set 1306ext_dabt_pending after an exit which was not either KVM_EXIT_MMIO, 1307KVM_EXIT_ARM_NISV, or KVM_EXIT_ARM_LDST64B. This feature is only available if 1308the system supports KVM_CAP_ARM_INJECT_EXT_DABT. This is a helper which 1309provides commonality in how userspace reports accesses for the above cases to 1310guests, across different userspace implementations. Nevertheless, userspace 1311can still emulate all Arm exceptions by manipulating individual registers 1312using the KVM_SET_ONE_REG API. 1313 1314See KVM_GET_VCPU_EVENTS for the data structure. 1315 1316Calling this ioctl on a vCPU that hasn't been initialized will return 1317-ENOEXEC. 1318 13194.33 KVM_GET_DEBUGREGS 1320---------------------- 1321 1322:Capability: KVM_CAP_DEBUGREGS 1323:Architectures: x86 1324:Type: vcpu ioctl 1325:Parameters: struct kvm_debugregs (out) 1326:Returns: 0 on success, -1 on error 1327 1328Reads debug registers from the vcpu. 1329 1330:: 1331 1332 struct kvm_debugregs { 1333 __u64 db[4]; 1334 __u64 dr6; 1335 __u64 dr7; 1336 __u64 flags; 1337 __u64 reserved[9]; 1338 }; 1339 1340 13414.34 KVM_SET_DEBUGREGS 1342---------------------- 1343 1344:Capability: KVM_CAP_DEBUGREGS 1345:Architectures: x86 1346:Type: vcpu ioctl 1347:Parameters: struct kvm_debugregs (in) 1348:Returns: 0 on success, -1 on error 1349 1350Writes debug registers into the vcpu. 1351 1352See KVM_GET_DEBUGREGS for the data structure. The flags field is unused 1353yet and must be cleared on entry. 1354 1355 13564.35 KVM_SET_USER_MEMORY_REGION 1357------------------------------- 1358 1359:Capability: KVM_CAP_USER_MEMORY 1360:Architectures: all 1361:Type: vm ioctl 1362:Parameters: struct kvm_userspace_memory_region (in) 1363:Returns: 0 on success, -1 on error 1364 1365:: 1366 1367 struct kvm_userspace_memory_region { 1368 __u32 slot; 1369 __u32 flags; 1370 __u64 guest_phys_addr; 1371 __u64 memory_size; /* bytes */ 1372 __u64 userspace_addr; /* start of the userspace allocated memory */ 1373 }; 1374 1375 /* for kvm_userspace_memory_region::flags */ 1376 #define KVM_MEM_LOG_DIRTY_PAGES (1UL << 0) 1377 #define KVM_MEM_READONLY (1UL << 1) 1378 1379This ioctl allows the user to create, modify or delete a guest physical 1380memory slot. Bits 0-15 of "slot" specify the slot id and this value 1381should be less than the maximum number of user memory slots supported per 1382VM. The maximum allowed slots can be queried using KVM_CAP_NR_MEMSLOTS. 1383Slots may not overlap in guest physical address space. 1384 1385If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 of "slot" 1386specifies the address space which is being modified. They must be 1387less than the value that KVM_CHECK_EXTENSION returns for the 1388KVM_CAP_MULTI_ADDRESS_SPACE capability. Slots in separate address spaces 1389are unrelated; the restriction on overlapping slots only applies within 1390each address space. 1391 1392Deleting a slot is done by passing zero for memory_size. When changing 1393an existing slot, it may be moved in the guest physical memory space, 1394or its flags may be modified, but it may not be resized. 1395 1396Memory for the region is taken starting at the address denoted by the 1397field userspace_addr, which must point at user addressable memory for 1398the entire memory slot size. Any object may back this memory, including 1399anonymous memory, ordinary files, and hugetlbfs. Changes in the backing 1400of the memory region are automatically reflected into the guest. 1401For example, an mmap() that affects the region will be made visible 1402immediately. Another example is madvise(MADV_DROP). 1403 1404On architectures that support a form of address tagging, userspace_addr must 1405be an untagged address. 1406 1407It is recommended that the lower 21 bits of guest_phys_addr and userspace_addr 1408be identical. This allows large pages in the guest to be backed by large 1409pages in the host. 1410 1411The flags field supports two flags: KVM_MEM_LOG_DIRTY_PAGES and 1412KVM_MEM_READONLY. The former can be set to instruct KVM to keep track of 1413writes to memory within the slot. See KVM_GET_DIRTY_LOG ioctl to know how to 1414use it. The latter can be set, if KVM_CAP_READONLY_MEM capability allows it, 1415to make a new slot read-only. In this case, writes to this memory will be 1416posted to userspace as KVM_EXIT_MMIO exits. 1417 1418For TDX guest, deleting/moving memory region loses guest memory contents. 1419Read only region isn't supported. Only as-id 0 is supported. 1420 1421Note: On arm64, a write generated by the page-table walker (to update 1422the Access and Dirty flags, for example) never results in a 1423KVM_EXIT_MMIO exit when the slot has the KVM_MEM_READONLY flag. This 1424is because KVM cannot provide the data that would be written by the 1425page-table walker, making it impossible to emulate the access. 1426Instead, an abort (data abort if the cause of the page-table update 1427was a load or a store, instruction abort if it was an instruction 1428fetch) is injected in the guest. 1429 1430S390: 1431^^^^^ 1432 1433Returns -EINVAL or -EEXIST if the VM has the KVM_VM_S390_UCONTROL flag set. 1434Returns -EINVAL if called on a protected VM. 1435 14364.36 KVM_SET_TSS_ADDR 1437--------------------- 1438 1439:Capability: KVM_CAP_SET_TSS_ADDR 1440:Architectures: x86 1441:Type: vm ioctl 1442:Parameters: unsigned long tss_address (in) 1443:Returns: 0 on success, -1 on error 1444 1445This ioctl defines the physical address of a three-page region in the guest 1446physical address space. The region must be within the first 4GB of the 1447guest physical address space and must not conflict with any memory slot 1448or any mmio address. The guest may malfunction if it accesses this memory 1449region. 1450 1451This ioctl is required on Intel-based hosts. This is needed on Intel hardware 1452because of a quirk in the virtualization implementation (see the internals 1453documentation when it pops into existence). 1454 1455 1456.. _KVM_ENABLE_CAP: 1457 14584.37 KVM_ENABLE_CAP 1459------------------- 1460 1461:Capability: KVM_CAP_ENABLE_CAP 1462:Architectures: mips, ppc, s390, x86, loongarch 1463:Type: vcpu ioctl 1464:Parameters: struct kvm_enable_cap (in) 1465:Returns: 0 on success; -1 on error 1466 1467:Capability: KVM_CAP_ENABLE_CAP_VM 1468:Architectures: all 1469:Type: vm ioctl 1470:Parameters: struct kvm_enable_cap (in) 1471:Returns: 0 on success; -1 on error 1472 1473.. note:: 1474 1475 Not all extensions are enabled by default. Using this ioctl the application 1476 can enable an extension, making it available to the guest. 1477 1478On systems that do not support this ioctl, it always fails. On systems that 1479do support it, it only works for extensions that are supported for enablement. 1480 1481To check if a capability can be enabled, the KVM_CHECK_EXTENSION ioctl should 1482be used. 1483 1484:: 1485 1486 struct kvm_enable_cap { 1487 /* in */ 1488 __u32 cap; 1489 1490The capability that is supposed to get enabled. 1491 1492:: 1493 1494 __u32 flags; 1495 1496A bitfield indicating future enhancements. Has to be 0 for now. 1497 1498:: 1499 1500 __u64 args[4]; 1501 1502Arguments for enabling a feature. If a feature needs initial values to 1503function properly, this is the place to put them. 1504 1505:: 1506 1507 __u8 pad[64]; 1508 }; 1509 1510The vcpu ioctl should be used for vcpu-specific capabilities, the vm ioctl 1511for vm-wide capabilities. 1512 15134.38 KVM_GET_MP_STATE 1514--------------------- 1515 1516:Capability: KVM_CAP_MP_STATE 1517:Architectures: x86, s390, arm64, riscv, loongarch 1518:Type: vcpu ioctl 1519:Parameters: struct kvm_mp_state (out) 1520:Returns: 0 on success; -1 on error 1521 1522:: 1523 1524 struct kvm_mp_state { 1525 __u32 mp_state; 1526 }; 1527 1528Returns the vcpu's current "multiprocessing state" (though also valid on 1529uniprocessor guests). 1530 1531Possible values are: 1532 1533 ========================== =============================================== 1534 KVM_MP_STATE_RUNNABLE the vcpu is currently running 1535 [x86,arm64,riscv,loongarch] 1536 KVM_MP_STATE_UNINITIALIZED the vcpu is an application processor (AP) 1537 which has not yet received an INIT signal [x86] 1538 KVM_MP_STATE_INIT_RECEIVED the vcpu has received an INIT signal, and is 1539 now ready for a SIPI [x86] 1540 KVM_MP_STATE_HALTED the vcpu has executed a HLT instruction and 1541 is waiting for an interrupt [x86] 1542 KVM_MP_STATE_SIPI_RECEIVED the vcpu has just received a SIPI (vector 1543 accessible via KVM_GET_VCPU_EVENTS) [x86] 1544 KVM_MP_STATE_STOPPED the vcpu is stopped [s390,arm64,riscv] 1545 KVM_MP_STATE_CHECK_STOP the vcpu is in a special error state [s390] 1546 KVM_MP_STATE_OPERATING the vcpu is operating (running or halted) 1547 [s390] 1548 KVM_MP_STATE_LOAD the vcpu is in a special load/startup state 1549 [s390] 1550 KVM_MP_STATE_SUSPENDED the vcpu is in a suspend state and is waiting 1551 for a wakeup event [arm64] 1552 ========================== =============================================== 1553 1554On x86, this ioctl is only useful after KVM_CREATE_IRQCHIP. Without an 1555in-kernel irqchip, the multiprocessing state must be maintained by userspace on 1556these architectures. 1557 1558For arm64: 1559^^^^^^^^^^ 1560 1561If a vCPU is in the KVM_MP_STATE_SUSPENDED state, KVM will emulate the 1562architectural execution of a WFI instruction. 1563 1564If a wakeup event is recognized, KVM will exit to userspace with a 1565KVM_SYSTEM_EVENT exit, where the event type is KVM_SYSTEM_EVENT_WAKEUP. If 1566userspace wants to honor the wakeup, it must set the vCPU's MP state to 1567KVM_MP_STATE_RUNNABLE. If it does not, KVM will continue to await a wakeup 1568event in subsequent calls to KVM_RUN. 1569 1570.. warning:: 1571 1572 If userspace intends to keep the vCPU in a SUSPENDED state, it is 1573 strongly recommended that userspace take action to suppress the 1574 wakeup event (such as masking an interrupt). Otherwise, subsequent 1575 calls to KVM_RUN will immediately exit with a KVM_SYSTEM_EVENT_WAKEUP 1576 event and inadvertently waste CPU cycles. 1577 1578 Additionally, if userspace takes action to suppress a wakeup event, 1579 it is strongly recommended that it also restores the vCPU to its 1580 original state when the vCPU is made RUNNABLE again. For example, 1581 if userspace masked a pending interrupt to suppress the wakeup, 1582 the interrupt should be unmasked before returning control to the 1583 guest. 1584 1585For riscv: 1586^^^^^^^^^^ 1587 1588The only states that are valid are KVM_MP_STATE_STOPPED and 1589KVM_MP_STATE_RUNNABLE which reflect if the vcpu is paused or not. 1590 1591On LoongArch, only the KVM_MP_STATE_RUNNABLE state is used to reflect 1592whether the vcpu is runnable. 1593 15944.39 KVM_SET_MP_STATE 1595--------------------- 1596 1597:Capability: KVM_CAP_MP_STATE 1598:Architectures: x86, s390, arm64, riscv, loongarch 1599:Type: vcpu ioctl 1600:Parameters: struct kvm_mp_state (in) 1601:Returns: 0 on success; -1 on error 1602 1603Sets the vcpu's current "multiprocessing state"; see KVM_GET_MP_STATE for 1604arguments. 1605 1606On x86, this ioctl is only useful after KVM_CREATE_IRQCHIP. Without an 1607in-kernel irqchip, the multiprocessing state must be maintained by userspace on 1608these architectures. 1609 1610For arm64/riscv: 1611^^^^^^^^^^^^^^^^ 1612 1613The only states that are valid are KVM_MP_STATE_STOPPED and 1614KVM_MP_STATE_RUNNABLE which reflect if the vcpu should be paused or not. 1615 1616On LoongArch, only the KVM_MP_STATE_RUNNABLE state is used to reflect 1617whether the vcpu is runnable. 1618 16194.40 KVM_SET_IDENTITY_MAP_ADDR 1620------------------------------ 1621 1622:Capability: KVM_CAP_SET_IDENTITY_MAP_ADDR 1623:Architectures: x86 1624:Type: vm ioctl 1625:Parameters: unsigned long identity (in) 1626:Returns: 0 on success, -1 on error 1627 1628This ioctl defines the physical address of a one-page region in the guest 1629physical address space. The region must be within the first 4GB of the 1630guest physical address space and must not conflict with any memory slot 1631or any mmio address. The guest may malfunction if it accesses this memory 1632region. 1633 1634Setting the address to 0 will result in resetting the address to its default 1635(0xfffbc000). 1636 1637This ioctl is required on Intel-based hosts. This is needed on Intel hardware 1638because of a quirk in the virtualization implementation (see the internals 1639documentation when it pops into existence). 1640 1641Fails if any VCPU has already been created. 1642 16434.41 KVM_SET_BOOT_CPU_ID 1644------------------------ 1645 1646:Capability: KVM_CAP_SET_BOOT_CPU_ID 1647:Architectures: x86 1648:Type: vm ioctl 1649:Parameters: unsigned long vcpu_id 1650:Returns: 0 on success, -1 on error 1651 1652Define which vcpu is the Bootstrap Processor (BSP). Values are the same 1653as the vcpu id in KVM_CREATE_VCPU. If this ioctl is not called, the default 1654is vcpu 0. This ioctl has to be called before vcpu creation, 1655otherwise it will return EBUSY error. 1656 1657 16584.42 KVM_GET_XSAVE 1659------------------ 1660 1661:Capability: KVM_CAP_XSAVE 1662:Architectures: x86 1663:Type: vcpu ioctl 1664:Parameters: struct kvm_xsave (out) 1665:Returns: 0 on success, -1 on error 1666 1667 1668:: 1669 1670 struct kvm_xsave { 1671 __u32 region[1024]; 1672 __u32 extra[0]; 1673 }; 1674 1675This ioctl would copy current vcpu's xsave struct to the userspace. 1676 1677 16784.43 KVM_SET_XSAVE 1679------------------ 1680 1681:Capability: KVM_CAP_XSAVE and KVM_CAP_XSAVE2 1682:Architectures: x86 1683:Type: vcpu ioctl 1684:Parameters: struct kvm_xsave (in) 1685:Returns: 0 on success, -1 on error 1686 1687:: 1688 1689 1690 struct kvm_xsave { 1691 __u32 region[1024]; 1692 __u32 extra[0]; 1693 }; 1694 1695This ioctl would copy userspace's xsave struct to the kernel. It copies 1696as many bytes as are returned by KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2), 1697when invoked on the vm file descriptor. The size value returned by 1698KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2) will always be at least 4096. 1699Currently, it is only greater than 4096 if a dynamic feature has been 1700enabled with ``arch_prctl()``, but this may change in the future. 1701 1702The offsets of the state save areas in struct kvm_xsave follow the 1703contents of CPUID leaf 0xD on the host. 1704 1705 17064.44 KVM_GET_XCRS 1707----------------- 1708 1709:Capability: KVM_CAP_XCRS 1710:Architectures: x86 1711:Type: vcpu ioctl 1712:Parameters: struct kvm_xcrs (out) 1713:Returns: 0 on success, -1 on error 1714 1715:: 1716 1717 struct kvm_xcr { 1718 __u32 xcr; 1719 __u32 reserved; 1720 __u64 value; 1721 }; 1722 1723 struct kvm_xcrs { 1724 __u32 nr_xcrs; 1725 __u32 flags; 1726 struct kvm_xcr xcrs[KVM_MAX_XCRS]; 1727 __u64 padding[16]; 1728 }; 1729 1730This ioctl would copy current vcpu's xcrs to the userspace. 1731 1732 17334.45 KVM_SET_XCRS 1734----------------- 1735 1736:Capability: KVM_CAP_XCRS 1737:Architectures: x86 1738:Type: vcpu ioctl 1739:Parameters: struct kvm_xcrs (in) 1740:Returns: 0 on success, -1 on error 1741 1742:: 1743 1744 struct kvm_xcr { 1745 __u32 xcr; 1746 __u32 reserved; 1747 __u64 value; 1748 }; 1749 1750 struct kvm_xcrs { 1751 __u32 nr_xcrs; 1752 __u32 flags; 1753 struct kvm_xcr xcrs[KVM_MAX_XCRS]; 1754 __u64 padding[16]; 1755 }; 1756 1757This ioctl would set vcpu's xcr to the value userspace specified. 1758 1759 17604.46 KVM_GET_SUPPORTED_CPUID 1761---------------------------- 1762 1763:Capability: KVM_CAP_EXT_CPUID 1764:Architectures: x86 1765:Type: system ioctl 1766:Parameters: struct kvm_cpuid2 (in/out) 1767:Returns: 0 on success, -1 on error 1768 1769:: 1770 1771 struct kvm_cpuid2 { 1772 __u32 nent; 1773 __u32 padding; 1774 struct kvm_cpuid_entry2 entries[0]; 1775 }; 1776 1777 #define KVM_CPUID_FLAG_SIGNIFCANT_INDEX BIT(0) 1778 #define KVM_CPUID_FLAG_STATEFUL_FUNC BIT(1) /* deprecated */ 1779 #define KVM_CPUID_FLAG_STATE_READ_NEXT BIT(2) /* deprecated */ 1780 1781 struct kvm_cpuid_entry2 { 1782 __u32 function; 1783 __u32 index; 1784 __u32 flags; 1785 __u32 eax; 1786 __u32 ebx; 1787 __u32 ecx; 1788 __u32 edx; 1789 __u32 padding[3]; 1790 }; 1791 1792This ioctl returns x86 cpuid features which are supported by both the 1793hardware and kvm in its default configuration. Userspace can use the 1794information returned by this ioctl to construct cpuid information (for 1795KVM_SET_CPUID2) that is consistent with hardware, kernel, and 1796userspace capabilities, and with user requirements (for example, the 1797user may wish to constrain cpuid to emulate older hardware, or for 1798feature consistency across a cluster). 1799 1800Dynamically-enabled feature bits need to be requested with 1801``arch_prctl()`` before calling this ioctl. Feature bits that have not 1802been requested are excluded from the result. 1803 1804Note that certain capabilities, such as KVM_CAP_X86_DISABLE_EXITS, may 1805expose cpuid features (e.g. MONITOR) which are not supported by kvm in 1806its default configuration. If userspace enables such capabilities, it 1807is responsible for modifying the results of this ioctl appropriately. 1808 1809Userspace invokes KVM_GET_SUPPORTED_CPUID by passing a kvm_cpuid2 structure 1810with the 'nent' field indicating the number of entries in the variable-size 1811array 'entries'. If the number of entries is too low to describe the cpu 1812capabilities, an error (E2BIG) is returned. If the number is too high, 1813the 'nent' field is adjusted and an error (ENOMEM) is returned. If the 1814number is just right, the 'nent' field is adjusted to the number of valid 1815entries in the 'entries' array, which is then filled. 1816 1817The entries returned are the host cpuid as returned by the cpuid instruction, 1818with unknown or unsupported features masked out. Some features (for example, 1819x2apic), may not be present in the host cpu, but are exposed by kvm if it can 1820emulate them efficiently. The fields in each entry are defined as follows: 1821 1822 function: 1823 the eax value used to obtain the entry 1824 1825 index: 1826 the ecx value used to obtain the entry (for entries that are 1827 affected by ecx) 1828 1829 flags: 1830 an OR of zero or more of the following: 1831 1832 KVM_CPUID_FLAG_SIGNIFCANT_INDEX: 1833 if the index field is valid 1834 1835 eax, ebx, ecx, edx: 1836 the values returned by the cpuid instruction for 1837 this function/index combination 1838 1839x2APIC (CPUID leaf 1, ecx[21) and TSC deadline timer (CPUID leaf 1, ecx[24]) 1840may be returned as true, but they depend on KVM_CREATE_IRQCHIP for in-kernel 1841emulation of the local APIC. TSC deadline timer support is also reported via:: 1842 1843 ioctl(KVM_CHECK_EXTENSION, KVM_CAP_TSC_DEADLINE_TIMER) 1844 1845if that returns true and you use KVM_CREATE_IRQCHIP, or if you emulate the 1846feature in userspace, then you can enable the feature for KVM_SET_CPUID2. 1847 1848Enabling x2APIC in KVM_SET_CPUID2 requires KVM_CREATE_IRQCHIP as KVM doesn't 1849support forwarding x2APIC MSR accesses to userspace, i.e. KVM does not support 1850emulating x2APIC in userspace. 1851 18524.47 KVM_PPC_GET_PVINFO 1853----------------------- 1854 1855:Capability: KVM_CAP_PPC_GET_PVINFO 1856:Architectures: ppc 1857:Type: vm ioctl 1858:Parameters: struct kvm_ppc_pvinfo (out) 1859:Returns: 0 on success, !0 on error 1860 1861:: 1862 1863 struct kvm_ppc_pvinfo { 1864 __u32 flags; 1865 __u32 hcall[4]; 1866 __u8 pad[108]; 1867 }; 1868 1869This ioctl fetches PV specific information that need to be passed to the guest 1870using the device tree or other means from vm context. 1871 1872The hcall array defines 4 instructions that make up a hypercall. 1873 1874If any additional field gets added to this structure later on, a bit for that 1875additional piece of information will be set in the flags bitmap. 1876 1877The flags bitmap is defined as:: 1878 1879 /* the host supports the ePAPR idle hcall 1880 #define KVM_PPC_PVINFO_FLAGS_EV_IDLE (1<<0) 1881 18824.52 KVM_SET_GSI_ROUTING 1883------------------------ 1884 1885:Capability: KVM_CAP_IRQ_ROUTING 1886:Architectures: x86 s390 arm64 1887:Type: vm ioctl 1888:Parameters: struct kvm_irq_routing (in) 1889:Returns: 0 on success, -1 on error 1890 1891Sets the GSI routing table entries, overwriting any previously set entries. 1892 1893On arm64, GSI routing has the following limitation: 1894 1895- GSI routing does not apply to KVM_IRQ_LINE but only to KVM_IRQFD. 1896 1897:: 1898 1899 struct kvm_irq_routing { 1900 __u32 nr; 1901 __u32 flags; 1902 struct kvm_irq_routing_entry entries[0]; 1903 }; 1904 1905No flags are specified so far, the corresponding field must be set to zero. 1906 1907:: 1908 1909 struct kvm_irq_routing_entry { 1910 __u32 gsi; 1911 __u32 type; 1912 __u32 flags; 1913 __u32 pad; 1914 union { 1915 struct kvm_irq_routing_irqchip irqchip; 1916 struct kvm_irq_routing_msi msi; 1917 struct kvm_irq_routing_s390_adapter adapter; 1918 struct kvm_irq_routing_hv_sint hv_sint; 1919 struct kvm_irq_routing_xen_evtchn xen_evtchn; 1920 __u32 pad[8]; 1921 } u; 1922 }; 1923 1924 /* gsi routing entry types */ 1925 #define KVM_IRQ_ROUTING_IRQCHIP 1 1926 #define KVM_IRQ_ROUTING_MSI 2 1927 #define KVM_IRQ_ROUTING_S390_ADAPTER 3 1928 #define KVM_IRQ_ROUTING_HV_SINT 4 1929 #define KVM_IRQ_ROUTING_XEN_EVTCHN 5 1930 1931On s390, adding a KVM_IRQ_ROUTING_S390_ADAPTER is rejected on ucontrol VMs with 1932error -EINVAL. 1933 1934flags: 1935 1936- KVM_MSI_VALID_DEVID: used along with KVM_IRQ_ROUTING_MSI routing entry 1937 type, specifies that the devid field contains a valid value. The per-VM 1938 KVM_CAP_MSI_DEVID capability advertises the requirement to provide 1939 the device ID. If this capability is not available, userspace should 1940 never set the KVM_MSI_VALID_DEVID flag as the ioctl might fail. 1941- zero otherwise 1942 1943:: 1944 1945 struct kvm_irq_routing_irqchip { 1946 __u32 irqchip; 1947 __u32 pin; 1948 }; 1949 1950 struct kvm_irq_routing_msi { 1951 __u32 address_lo; 1952 __u32 address_hi; 1953 __u32 data; 1954 union { 1955 __u32 pad; 1956 __u32 devid; 1957 }; 1958 }; 1959 1960If KVM_MSI_VALID_DEVID is set, devid contains a unique device identifier 1961for the device that wrote the MSI message. For PCI, this is usually a 1962BDF identifier in the lower 16 bits. 1963 1964On x86, address_hi is ignored unless the KVM_X2APIC_API_USE_32BIT_IDS 1965feature of KVM_CAP_X2APIC_API capability is enabled. If it is enabled, 1966address_hi bits 31-8 provide bits 31-8 of the destination id. Bits 7-0 of 1967address_hi must be zero. 1968 1969:: 1970 1971 struct kvm_irq_routing_s390_adapter { 1972 __u64 ind_addr; 1973 __u64 summary_addr; 1974 __u64 ind_offset; 1975 __u32 summary_offset; 1976 __u32 adapter_id; 1977 }; 1978 1979 struct kvm_irq_routing_hv_sint { 1980 __u32 vcpu; 1981 __u32 sint; 1982 }; 1983 1984 struct kvm_irq_routing_xen_evtchn { 1985 __u32 port; 1986 __u32 vcpu; 1987 __u32 priority; 1988 }; 1989 1990 1991When KVM_CAP_XEN_HVM includes the KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL bit 1992in its indication of supported features, routing to Xen event channels 1993is supported. Although the priority field is present, only the value 1994KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL is supported, which means delivery by 19952 level event channels. FIFO event channel support may be added in 1996the future. 1997 1998 19994.55 KVM_SET_TSC_KHZ 2000-------------------- 2001 2002:Capability: KVM_CAP_TSC_CONTROL / KVM_CAP_VM_TSC_CONTROL 2003:Architectures: x86 2004:Type: vcpu ioctl / vm ioctl 2005:Parameters: virtual tsc_khz 2006:Returns: 0 on success, -1 on error 2007 2008Specifies the tsc frequency for the virtual machine. The unit of the 2009frequency is KHz. 2010 2011If the KVM_CAP_VM_TSC_CONTROL capability is advertised, this can also 2012be used as a vm ioctl to set the initial tsc frequency of subsequently 2013created vCPUs. Note, the vm ioctl is only allowed prior to creating vCPUs. 2014 2015For TSC protected Confidential Computing (CoCo) VMs where TSC frequency 2016is configured once at VM scope and remains unchanged during VM's 2017lifetime, the vm ioctl should be used to configure the TSC frequency 2018and the vcpu ioctl is not supported. 2019 2020Example of such CoCo VMs: TDX guests. 2021 20224.56 KVM_GET_TSC_KHZ 2023-------------------- 2024 2025:Capability: KVM_CAP_GET_TSC_KHZ / KVM_CAP_VM_TSC_CONTROL 2026:Architectures: x86 2027:Type: vcpu ioctl / vm ioctl 2028:Parameters: none 2029:Returns: virtual tsc-khz on success, negative value on error 2030 2031Returns the tsc frequency of the guest. The unit of the return value is 2032KHz. If the host has unstable tsc this ioctl returns -EIO instead as an 2033error. 2034 2035 20364.57 KVM_GET_LAPIC 2037------------------ 2038 2039:Capability: KVM_CAP_IRQCHIP 2040:Architectures: x86 2041:Type: vcpu ioctl 2042:Parameters: struct kvm_lapic_state (out) 2043:Returns: 0 on success, -1 on error 2044 2045:: 2046 2047 #define KVM_APIC_REG_SIZE 0x400 2048 struct kvm_lapic_state { 2049 char regs[KVM_APIC_REG_SIZE]; 2050 }; 2051 2052Reads the Local APIC registers and copies them into the input argument. The 2053data format and layout are the same as documented in the architecture manual. 2054 2055If KVM_X2APIC_API_USE_32BIT_IDS feature of KVM_CAP_X2APIC_API is 2056enabled, then the format of APIC_ID register depends on the APIC mode 2057(reported by MSR_IA32_APICBASE) of its VCPU. x2APIC stores APIC ID in 2058the APIC_ID register (bytes 32-35). xAPIC only allows an 8-bit APIC ID 2059which is stored in bits 31-24 of the APIC register, or equivalently in 2060byte 35 of struct kvm_lapic_state's regs field. KVM_GET_LAPIC must then 2061be called after MSR_IA32_APICBASE has been set with KVM_SET_MSR. 2062 2063If KVM_X2APIC_API_USE_32BIT_IDS feature is disabled, struct kvm_lapic_state 2064always uses xAPIC format. 2065 2066 20674.58 KVM_SET_LAPIC 2068------------------ 2069 2070:Capability: KVM_CAP_IRQCHIP 2071:Architectures: x86 2072:Type: vcpu ioctl 2073:Parameters: struct kvm_lapic_state (in) 2074:Returns: 0 on success, -1 on error 2075 2076:: 2077 2078 #define KVM_APIC_REG_SIZE 0x400 2079 struct kvm_lapic_state { 2080 char regs[KVM_APIC_REG_SIZE]; 2081 }; 2082 2083Copies the input argument into the Local APIC registers. The data format 2084and layout are the same as documented in the architecture manual. 2085 2086The format of the APIC ID register (bytes 32-35 of struct kvm_lapic_state's 2087regs field) depends on the state of the KVM_CAP_X2APIC_API capability. 2088See the note in KVM_GET_LAPIC. 2089 2090 20914.59 KVM_IOEVENTFD 2092------------------ 2093 2094:Capability: KVM_CAP_IOEVENTFD 2095:Architectures: all 2096:Type: vm ioctl 2097:Parameters: struct kvm_ioeventfd (in) 2098:Returns: 0 on success, !0 on error 2099 2100This ioctl attaches or detaches an ioeventfd to a legal pio/mmio address 2101within the guest. A guest write in the registered address will signal the 2102provided event instead of triggering an exit. 2103 2104:: 2105 2106 struct kvm_ioeventfd { 2107 __u64 datamatch; 2108 __u64 addr; /* legal pio/mmio address */ 2109 __u32 len; /* 0, 1, 2, 4, or 8 bytes */ 2110 __s32 fd; 2111 __u32 flags; 2112 __u8 pad[36]; 2113 }; 2114 2115For the special case of virtio-ccw devices on s390, the ioevent is matched 2116to a subchannel/virtqueue tuple instead. 2117 2118The following flags are defined:: 2119 2120 #define KVM_IOEVENTFD_FLAG_DATAMATCH (1 << kvm_ioeventfd_flag_nr_datamatch) 2121 #define KVM_IOEVENTFD_FLAG_PIO (1 << kvm_ioeventfd_flag_nr_pio) 2122 #define KVM_IOEVENTFD_FLAG_DEASSIGN (1 << kvm_ioeventfd_flag_nr_deassign) 2123 #define KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY \ 2124 (1 << kvm_ioeventfd_flag_nr_virtio_ccw_notify) 2125 2126If datamatch flag is set, the event will be signaled only if the written value 2127to the registered address is equal to datamatch in struct kvm_ioeventfd. 2128 2129For virtio-ccw devices, addr contains the subchannel id and datamatch the 2130virtqueue index. 2131 2132With KVM_CAP_IOEVENTFD_ANY_LENGTH, a zero length ioeventfd is allowed, and 2133the kernel will ignore the length of guest write and may get a faster vmexit. 2134The speedup may only apply to specific architectures, but the ioeventfd will 2135work anyway. 2136 21374.60 KVM_DIRTY_TLB 2138------------------ 2139 2140:Capability: KVM_CAP_SW_TLB 2141:Architectures: ppc 2142:Type: vcpu ioctl 2143:Parameters: struct kvm_dirty_tlb (in) 2144:Returns: 0 on success, -1 on error 2145 2146:: 2147 2148 struct kvm_dirty_tlb { 2149 __u64 bitmap; 2150 __u32 num_dirty; 2151 }; 2152 2153This must be called whenever userspace has changed an entry in the shared 2154TLB, prior to calling KVM_RUN on the associated vcpu. 2155 2156The "bitmap" field is the userspace address of an array. This array 2157consists of a number of bits, equal to the total number of TLB entries as 2158determined by the last successful call to ``KVM_ENABLE_CAP(KVM_CAP_SW_TLB)``, 2159rounded up to the nearest multiple of 64. 2160 2161Each bit corresponds to one TLB entry, ordered the same as in the shared TLB 2162array. 2163 2164The array is little-endian: the bit 0 is the least significant bit of the 2165first byte, bit 8 is the least significant bit of the second byte, etc. 2166This avoids any complications with differing word sizes. 2167 2168The "num_dirty" field is a performance hint for KVM to determine whether it 2169should skip processing the bitmap and just invalidate everything. It must 2170be set to the number of set bits in the bitmap. 2171 2172 21734.62 KVM_CREATE_SPAPR_TCE 2174------------------------- 2175 2176:Capability: KVM_CAP_SPAPR_TCE 2177:Architectures: powerpc 2178:Type: vm ioctl 2179:Parameters: struct kvm_create_spapr_tce (in) 2180:Returns: file descriptor for manipulating the created TCE table 2181 2182This creates a virtual TCE (translation control entry) table, which 2183is an IOMMU for PAPR-style virtual I/O. It is used to translate 2184logical addresses used in virtual I/O into guest physical addresses, 2185and provides a scatter/gather capability for PAPR virtual I/O. 2186 2187:: 2188 2189 /* for KVM_CAP_SPAPR_TCE */ 2190 struct kvm_create_spapr_tce { 2191 __u64 liobn; 2192 __u32 window_size; 2193 }; 2194 2195The liobn field gives the logical IO bus number for which to create a 2196TCE table. The window_size field specifies the size of the DMA window 2197which this TCE table will translate - the table will contain one 64 2198bit TCE entry for every 4kiB of the DMA window. 2199 2200When the guest issues an H_PUT_TCE hcall on a liobn for which a TCE 2201table has been created using this ioctl(), the kernel will handle it 2202in real mode, updating the TCE table. H_PUT_TCE calls for other 2203liobns will cause a vm exit and must be handled by userspace. 2204 2205The return value is a file descriptor which can be passed to mmap(2) 2206to map the created TCE table into userspace. This lets userspace read 2207the entries written by kernel-handled H_PUT_TCE calls, and also lets 2208userspace update the TCE table directly which is useful in some 2209circumstances. 2210 2211 22124.64 KVM_NMI 2213------------ 2214 2215:Capability: KVM_CAP_USER_NMI 2216:Architectures: x86 2217:Type: vcpu ioctl 2218:Parameters: none 2219:Returns: 0 on success, -1 on error 2220 2221Queues an NMI on the thread's vcpu. Note this is well defined only 2222when KVM_CREATE_IRQCHIP has not been called, since this is an interface 2223between the virtual cpu core and virtual local APIC. After KVM_CREATE_IRQCHIP 2224has been called, this interface is completely emulated within the kernel. 2225 2226To use this to emulate the LINT1 input with KVM_CREATE_IRQCHIP, use the 2227following algorithm: 2228 2229 - pause the vcpu 2230 - read the local APIC's state (KVM_GET_LAPIC) 2231 - check whether changing LINT1 will queue an NMI (see the LVT entry for LINT1) 2232 - if so, issue KVM_NMI 2233 - resume the vcpu 2234 2235Some guests configure the LINT1 NMI input to cause a panic, aiding in 2236debugging. 2237 2238 22394.65 KVM_S390_UCAS_MAP 2240---------------------- 2241 2242:Capability: KVM_CAP_S390_UCONTROL 2243:Architectures: s390 2244:Type: vcpu ioctl 2245:Parameters: struct kvm_s390_ucas_mapping (in) 2246:Returns: 0 in case of success 2247 2248The parameter is defined like this:: 2249 2250 struct kvm_s390_ucas_mapping { 2251 __u64 user_addr; 2252 __u64 vcpu_addr; 2253 __u64 length; 2254 }; 2255 2256This ioctl maps the memory at "user_addr" with the length "length" to 2257the vcpu's address space starting at "vcpu_addr". All parameters need to 2258be aligned by 1 megabyte. 2259 2260 22614.66 KVM_S390_UCAS_UNMAP 2262------------------------ 2263 2264:Capability: KVM_CAP_S390_UCONTROL 2265:Architectures: s390 2266:Type: vcpu ioctl 2267:Parameters: struct kvm_s390_ucas_mapping (in) 2268:Returns: 0 in case of success 2269 2270The parameter is defined like this:: 2271 2272 struct kvm_s390_ucas_mapping { 2273 __u64 user_addr; 2274 __u64 vcpu_addr; 2275 __u64 length; 2276 }; 2277 2278This ioctl unmaps the memory in the vcpu's address space starting at 2279"vcpu_addr" with the length "length". The field "user_addr" is ignored. 2280All parameters need to be aligned by 1 megabyte. 2281 2282 22834.67 KVM_S390_VCPU_FAULT 2284------------------------ 2285 2286:Capability: KVM_CAP_S390_UCONTROL 2287:Architectures: s390 2288:Type: vcpu ioctl 2289:Parameters: vcpu absolute address (in) 2290:Returns: 0 in case of success 2291 2292This call creates a page table entry on the virtual cpu's address space 2293(for user controlled virtual machines) or the virtual machine's address 2294space (for regular virtual machines). This only works for minor faults, 2295thus it's recommended to access subject memory page via the user page 2296table upfront. This is useful to handle validity intercepts for user 2297controlled virtual machines to fault in the virtual cpu's lowcore pages 2298prior to calling the KVM_RUN ioctl. 2299 2300 23014.68 KVM_SET_ONE_REG 2302-------------------- 2303 2304:Capability: KVM_CAP_ONE_REG 2305:Architectures: all 2306:Type: vcpu ioctl 2307:Parameters: struct kvm_one_reg (in) 2308:Returns: 0 on success, negative value on failure 2309 2310Errors: 2311 2312 ====== ============================================================ 2313 ENOENT no such register 2314 EINVAL invalid register ID, or no such register or used with VMs in 2315 protected virtualization mode on s390 2316 EPERM (arm64) register access not allowed before vcpu finalization 2317 EBUSY (riscv) changing register value not allowed after the vcpu 2318 has run at least once 2319 ====== ============================================================ 2320 2321(These error codes are indicative only: do not rely on a specific error 2322code being returned in a specific situation.) 2323 2324:: 2325 2326 struct kvm_one_reg { 2327 __u64 id; 2328 __u64 addr; 2329 }; 2330 2331Using this ioctl, a single vcpu register can be set to a specific value 2332defined by user space with the passed in struct kvm_one_reg, where id 2333refers to the register identifier as described below and addr is a pointer 2334to a variable with the respective size. There can be architecture agnostic 2335and architecture specific registers. Each have their own range of operation 2336and their own constants and width. To keep track of the implemented 2337registers, find a list below: 2338 2339 ======= =============================== ============ 2340 Arch Register Width (bits) 2341 ======= =============================== ============ 2342 PPC KVM_REG_PPC_HIOR 64 2343 PPC KVM_REG_PPC_IAC1 64 2344 PPC KVM_REG_PPC_IAC2 64 2345 PPC KVM_REG_PPC_IAC3 64 2346 PPC KVM_REG_PPC_IAC4 64 2347 PPC KVM_REG_PPC_DAC1 64 2348 PPC KVM_REG_PPC_DAC2 64 2349 PPC KVM_REG_PPC_DABR 64 2350 PPC KVM_REG_PPC_DSCR 64 2351 PPC KVM_REG_PPC_PURR 64 2352 PPC KVM_REG_PPC_SPURR 64 2353 PPC KVM_REG_PPC_DAR 64 2354 PPC KVM_REG_PPC_DSISR 32 2355 PPC KVM_REG_PPC_AMR 64 2356 PPC KVM_REG_PPC_UAMOR 64 2357 PPC KVM_REG_PPC_MMCR0 64 2358 PPC KVM_REG_PPC_MMCR1 64 2359 PPC KVM_REG_PPC_MMCRA 64 2360 PPC KVM_REG_PPC_MMCR2 64 2361 PPC KVM_REG_PPC_MMCRS 64 2362 PPC KVM_REG_PPC_MMCR3 64 2363 PPC KVM_REG_PPC_SIAR 64 2364 PPC KVM_REG_PPC_SDAR 64 2365 PPC KVM_REG_PPC_SIER 64 2366 PPC KVM_REG_PPC_SIER2 64 2367 PPC KVM_REG_PPC_SIER3 64 2368 PPC KVM_REG_PPC_PMC1 32 2369 PPC KVM_REG_PPC_PMC2 32 2370 PPC KVM_REG_PPC_PMC3 32 2371 PPC KVM_REG_PPC_PMC4 32 2372 PPC KVM_REG_PPC_PMC5 32 2373 PPC KVM_REG_PPC_PMC6 32 2374 PPC KVM_REG_PPC_PMC7 32 2375 PPC KVM_REG_PPC_PMC8 32 2376 PPC KVM_REG_PPC_FPR0 64 2377 ... 2378 PPC KVM_REG_PPC_FPR31 64 2379 PPC KVM_REG_PPC_VR0 128 2380 ... 2381 PPC KVM_REG_PPC_VR31 128 2382 PPC KVM_REG_PPC_VSR0 128 2383 ... 2384 PPC KVM_REG_PPC_VSR31 128 2385 PPC KVM_REG_PPC_FPSCR 64 2386 PPC KVM_REG_PPC_VSCR 32 2387 PPC KVM_REG_PPC_VPA_ADDR 64 2388 PPC KVM_REG_PPC_VPA_SLB 128 2389 PPC KVM_REG_PPC_VPA_DTL 128 2390 PPC KVM_REG_PPC_EPCR 32 2391 PPC KVM_REG_PPC_EPR 32 2392 PPC KVM_REG_PPC_TCR 32 2393 PPC KVM_REG_PPC_TSR 32 2394 PPC KVM_REG_PPC_OR_TSR 32 2395 PPC KVM_REG_PPC_CLEAR_TSR 32 2396 PPC KVM_REG_PPC_MAS0 32 2397 PPC KVM_REG_PPC_MAS1 32 2398 PPC KVM_REG_PPC_MAS2 64 2399 PPC KVM_REG_PPC_MAS7_3 64 2400 PPC KVM_REG_PPC_MAS4 32 2401 PPC KVM_REG_PPC_MAS6 32 2402 PPC KVM_REG_PPC_MMUCFG 32 2403 PPC KVM_REG_PPC_TLB0CFG 32 2404 PPC KVM_REG_PPC_TLB1CFG 32 2405 PPC KVM_REG_PPC_TLB2CFG 32 2406 PPC KVM_REG_PPC_TLB3CFG 32 2407 PPC KVM_REG_PPC_TLB0PS 32 2408 PPC KVM_REG_PPC_TLB1PS 32 2409 PPC KVM_REG_PPC_TLB2PS 32 2410 PPC KVM_REG_PPC_TLB3PS 32 2411 PPC KVM_REG_PPC_EPTCFG 32 2412 PPC KVM_REG_PPC_ICP_STATE 64 2413 PPC KVM_REG_PPC_VP_STATE 128 2414 PPC KVM_REG_PPC_TB_OFFSET 64 2415 PPC KVM_REG_PPC_SPMC1 32 2416 PPC KVM_REG_PPC_SPMC2 32 2417 PPC KVM_REG_PPC_IAMR 64 2418 PPC KVM_REG_PPC_TFHAR 64 2419 PPC KVM_REG_PPC_TFIAR 64 2420 PPC KVM_REG_PPC_TEXASR 64 2421 PPC KVM_REG_PPC_FSCR 64 2422 PPC KVM_REG_PPC_PSPB 32 2423 PPC KVM_REG_PPC_EBBHR 64 2424 PPC KVM_REG_PPC_EBBRR 64 2425 PPC KVM_REG_PPC_BESCR 64 2426 PPC KVM_REG_PPC_TAR 64 2427 PPC KVM_REG_PPC_DPDES 64 2428 PPC KVM_REG_PPC_DAWR 64 2429 PPC KVM_REG_PPC_DAWRX 64 2430 PPC KVM_REG_PPC_CIABR 64 2431 PPC KVM_REG_PPC_IC 64 2432 PPC KVM_REG_PPC_VTB 64 2433 PPC KVM_REG_PPC_CSIGR 64 2434 PPC KVM_REG_PPC_TACR 64 2435 PPC KVM_REG_PPC_TCSCR 64 2436 PPC KVM_REG_PPC_PID 64 2437 PPC KVM_REG_PPC_ACOP 64 2438 PPC KVM_REG_PPC_VRSAVE 32 2439 PPC KVM_REG_PPC_LPCR 32 2440 PPC KVM_REG_PPC_LPCR_64 64 2441 PPC KVM_REG_PPC_PPR 64 2442 PPC KVM_REG_PPC_ARCH_COMPAT 32 2443 PPC KVM_REG_PPC_DABRX 32 2444 PPC KVM_REG_PPC_WORT 64 2445 PPC KVM_REG_PPC_SPRG9 64 2446 PPC KVM_REG_PPC_DBSR 32 2447 PPC KVM_REG_PPC_TIDR 64 2448 PPC KVM_REG_PPC_PSSCR 64 2449 PPC KVM_REG_PPC_DEC_EXPIRY 64 2450 PPC KVM_REG_PPC_PTCR 64 2451 PPC KVM_REG_PPC_HASHKEYR 64 2452 PPC KVM_REG_PPC_HASHPKEYR 64 2453 PPC KVM_REG_PPC_DAWR1 64 2454 PPC KVM_REG_PPC_DAWRX1 64 2455 PPC KVM_REG_PPC_DEXCR 64 2456 PPC KVM_REG_PPC_TM_GPR0 64 2457 ... 2458 PPC KVM_REG_PPC_TM_GPR31 64 2459 PPC KVM_REG_PPC_TM_VSR0 128 2460 ... 2461 PPC KVM_REG_PPC_TM_VSR63 128 2462 PPC KVM_REG_PPC_TM_CR 64 2463 PPC KVM_REG_PPC_TM_LR 64 2464 PPC KVM_REG_PPC_TM_CTR 64 2465 PPC KVM_REG_PPC_TM_FPSCR 64 2466 PPC KVM_REG_PPC_TM_AMR 64 2467 PPC KVM_REG_PPC_TM_PPR 64 2468 PPC KVM_REG_PPC_TM_VRSAVE 64 2469 PPC KVM_REG_PPC_TM_VSCR 32 2470 PPC KVM_REG_PPC_TM_DSCR 64 2471 PPC KVM_REG_PPC_TM_TAR 64 2472 PPC KVM_REG_PPC_TM_XER 64 2473 2474 MIPS KVM_REG_MIPS_R0 64 2475 ... 2476 MIPS KVM_REG_MIPS_R31 64 2477 MIPS KVM_REG_MIPS_HI 64 2478 MIPS KVM_REG_MIPS_LO 64 2479 MIPS KVM_REG_MIPS_PC 64 2480 MIPS KVM_REG_MIPS_CP0_INDEX 32 2481 MIPS KVM_REG_MIPS_CP0_ENTRYLO0 64 2482 MIPS KVM_REG_MIPS_CP0_ENTRYLO1 64 2483 MIPS KVM_REG_MIPS_CP0_CONTEXT 64 2484 MIPS KVM_REG_MIPS_CP0_CONTEXTCONFIG 32 2485 MIPS KVM_REG_MIPS_CP0_USERLOCAL 64 2486 MIPS KVM_REG_MIPS_CP0_XCONTEXTCONFIG 64 2487 MIPS KVM_REG_MIPS_CP0_PAGEMASK 32 2488 MIPS KVM_REG_MIPS_CP0_PAGEGRAIN 32 2489 MIPS KVM_REG_MIPS_CP0_SEGCTL0 64 2490 MIPS KVM_REG_MIPS_CP0_SEGCTL1 64 2491 MIPS KVM_REG_MIPS_CP0_SEGCTL2 64 2492 MIPS KVM_REG_MIPS_CP0_PWBASE 64 2493 MIPS KVM_REG_MIPS_CP0_PWFIELD 64 2494 MIPS KVM_REG_MIPS_CP0_PWSIZE 64 2495 MIPS KVM_REG_MIPS_CP0_WIRED 32 2496 MIPS KVM_REG_MIPS_CP0_PWCTL 32 2497 MIPS KVM_REG_MIPS_CP0_HWRENA 32 2498 MIPS KVM_REG_MIPS_CP0_BADVADDR 64 2499 MIPS KVM_REG_MIPS_CP0_BADINSTR 32 2500 MIPS KVM_REG_MIPS_CP0_BADINSTRP 32 2501 MIPS KVM_REG_MIPS_CP0_COUNT 32 2502 MIPS KVM_REG_MIPS_CP0_ENTRYHI 64 2503 MIPS KVM_REG_MIPS_CP0_COMPARE 32 2504 MIPS KVM_REG_MIPS_CP0_STATUS 32 2505 MIPS KVM_REG_MIPS_CP0_INTCTL 32 2506 MIPS KVM_REG_MIPS_CP0_CAUSE 32 2507 MIPS KVM_REG_MIPS_CP0_EPC 64 2508 MIPS KVM_REG_MIPS_CP0_PRID 32 2509 MIPS KVM_REG_MIPS_CP0_EBASE 64 2510 MIPS KVM_REG_MIPS_CP0_CONFIG 32 2511 MIPS KVM_REG_MIPS_CP0_CONFIG1 32 2512 MIPS KVM_REG_MIPS_CP0_CONFIG2 32 2513 MIPS KVM_REG_MIPS_CP0_CONFIG3 32 2514 MIPS KVM_REG_MIPS_CP0_CONFIG4 32 2515 MIPS KVM_REG_MIPS_CP0_CONFIG5 32 2516 MIPS KVM_REG_MIPS_CP0_CONFIG7 32 2517 MIPS KVM_REG_MIPS_CP0_XCONTEXT 64 2518 MIPS KVM_REG_MIPS_CP0_ERROREPC 64 2519 MIPS KVM_REG_MIPS_CP0_KSCRATCH1 64 2520 MIPS KVM_REG_MIPS_CP0_KSCRATCH2 64 2521 MIPS KVM_REG_MIPS_CP0_KSCRATCH3 64 2522 MIPS KVM_REG_MIPS_CP0_KSCRATCH4 64 2523 MIPS KVM_REG_MIPS_CP0_KSCRATCH5 64 2524 MIPS KVM_REG_MIPS_CP0_KSCRATCH6 64 2525 MIPS KVM_REG_MIPS_CP0_MAAR(0..63) 64 2526 MIPS KVM_REG_MIPS_COUNT_CTL 64 2527 MIPS KVM_REG_MIPS_COUNT_RESUME 64 2528 MIPS KVM_REG_MIPS_COUNT_HZ 64 2529 MIPS KVM_REG_MIPS_FPR_32(0..31) 32 2530 MIPS KVM_REG_MIPS_FPR_64(0..31) 64 2531 MIPS KVM_REG_MIPS_VEC_128(0..31) 128 2532 MIPS KVM_REG_MIPS_FCR_IR 32 2533 MIPS KVM_REG_MIPS_FCR_CSR 32 2534 MIPS KVM_REG_MIPS_MSA_IR 32 2535 MIPS KVM_REG_MIPS_MSA_CSR 32 2536 ======= =============================== ============ 2537 2538ARM registers are mapped using the lower 32 bits. The upper 16 of that 2539is the register group type, or coprocessor number: 2540 2541ARM core registers have the following id bit patterns:: 2542 2543 0x4020 0000 0010 <index into the kvm_regs struct:16> 2544 2545ARM 32-bit CP15 registers have the following id bit patterns:: 2546 2547 0x4020 0000 000F <zero:1> <crn:4> <crm:4> <opc1:4> <opc2:3> 2548 2549ARM 64-bit CP15 registers have the following id bit patterns:: 2550 2551 0x4030 0000 000F <zero:1> <zero:4> <crm:4> <opc1:4> <zero:3> 2552 2553ARM CCSIDR registers are demultiplexed by CSSELR value:: 2554 2555 0x4020 0000 0011 00 <csselr:8> 2556 2557ARM 32-bit VFP control registers have the following id bit patterns:: 2558 2559 0x4020 0000 0012 1 <regno:12> 2560 2561ARM 64-bit FP registers have the following id bit patterns:: 2562 2563 0x4030 0000 0012 0 <regno:12> 2564 2565ARM firmware pseudo-registers have the following bit pattern:: 2566 2567 0x4030 0000 0014 <regno:16> 2568 2569 2570arm64 registers are mapped using the lower 32 bits. The upper 16 of 2571that is the register group type, or coprocessor number: 2572 2573arm64 core/FP-SIMD registers have the following id bit patterns. Note 2574that the size of the access is variable, as the kvm_regs structure 2575contains elements ranging from 32 to 128 bits. The index is a 32bit 2576value in the kvm_regs structure seen as a 32bit array:: 2577 2578 0x60x0 0000 0010 <index into the kvm_regs struct:16> 2579 2580Specifically: 2581 2582======================= ========= ===== ======================================= 2583 Encoding Register Bits kvm_regs member 2584======================= ========= ===== ======================================= 2585 0x6030 0000 0010 0000 X0 64 regs.regs[0] 2586 0x6030 0000 0010 0002 X1 64 regs.regs[1] 2587 ... 2588 0x6030 0000 0010 003c X30 64 regs.regs[30] 2589 0x6030 0000 0010 003e SP 64 regs.sp 2590 0x6030 0000 0010 0040 PC 64 regs.pc 2591 0x6030 0000 0010 0042 PSTATE 64 regs.pstate 2592 0x6030 0000 0010 0044 SP_EL1 64 sp_el1 2593 0x6030 0000 0010 0046 ELR_EL1 64 elr_el1 2594 0x6030 0000 0010 0048 SPSR_EL1 64 spsr[KVM_SPSR_EL1] (alias SPSR_SVC) 2595 0x6030 0000 0010 004a SPSR_ABT 64 spsr[KVM_SPSR_ABT] 2596 0x6030 0000 0010 004c SPSR_UND 64 spsr[KVM_SPSR_UND] 2597 0x6030 0000 0010 004e SPSR_IRQ 64 spsr[KVM_SPSR_IRQ] 2598 0x6030 0000 0010 0050 SPSR_FIQ 64 spsr[KVM_SPSR_FIQ] 2599 0x6040 0000 0010 0054 V0 128 fp_regs.vregs[0] [1]_ 2600 0x6040 0000 0010 0058 V1 128 fp_regs.vregs[1] [1]_ 2601 ... 2602 0x6040 0000 0010 00d0 V31 128 fp_regs.vregs[31] [1]_ 2603 0x6020 0000 0010 00d4 FPSR 32 fp_regs.fpsr 2604 0x6020 0000 0010 00d5 FPCR 32 fp_regs.fpcr 2605======================= ========= ===== ======================================= 2606 2607.. [1] These encodings are not accepted for SVE-enabled vcpus. See 2608 :ref:`KVM_ARM_VCPU_INIT`. 2609 2610 The equivalent register content can be accessed via bits [127:0] of 2611 the corresponding SVE Zn registers instead for vcpus that have SVE 2612 enabled (see below). 2613 2614arm64 CCSIDR registers are demultiplexed by CSSELR value:: 2615 2616 0x6020 0000 0011 00 <csselr:8> 2617 2618arm64 system registers have the following id bit patterns:: 2619 2620 0x6030 0000 0013 <op0:2> <op1:3> <crn:4> <crm:4> <op2:3> 2621 2622.. warning:: 2623 2624 Two system register IDs do not follow the specified pattern. These 2625 are KVM_REG_ARM_TIMER_CVAL and KVM_REG_ARM_TIMER_CNT, which map to 2626 system registers CNTV_CVAL_EL0 and CNTVCT_EL0 respectively. These 2627 two had their values accidentally swapped, which means TIMER_CVAL is 2628 derived from the register encoding for CNTVCT_EL0 and TIMER_CNT is 2629 derived from the register encoding for CNTV_CVAL_EL0. As this is 2630 API, it must remain this way. 2631 2632arm64 firmware pseudo-registers have the following bit pattern:: 2633 2634 0x6030 0000 0014 <regno:16> 2635 2636arm64 SVE registers have the following bit patterns:: 2637 2638 0x6080 0000 0015 00 <n:5> <slice:5> Zn bits[2048*slice + 2047 : 2048*slice] 2639 0x6050 0000 0015 04 <n:4> <slice:5> Pn bits[256*slice + 255 : 256*slice] 2640 0x6050 0000 0015 060 <slice:5> FFR bits[256*slice + 255 : 256*slice] 2641 0x6060 0000 0015 ffff KVM_REG_ARM64_SVE_VLS pseudo-register 2642 2643Access to register IDs where 2048 * slice >= 128 * max_vq will fail with 2644ENOENT. max_vq is the vcpu's maximum supported vector length in 128-bit 2645quadwords: see [2]_ below. 2646 2647These registers are only accessible on vcpus for which SVE is enabled. 2648See KVM_ARM_VCPU_INIT for details. 2649 2650In addition, except for KVM_REG_ARM64_SVE_VLS, these registers are not 2651accessible until the vcpu's SVE configuration has been finalized 2652using KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE). See KVM_ARM_VCPU_INIT 2653and KVM_ARM_VCPU_FINALIZE for more information about this procedure. 2654 2655KVM_REG_ARM64_SVE_VLS is a pseudo-register that allows the set of vector 2656lengths supported by the vcpu to be discovered and configured by 2657userspace. When transferred to or from user memory via KVM_GET_ONE_REG 2658or KVM_SET_ONE_REG, the value of this register is of type 2659__u64[KVM_ARM64_SVE_VLS_WORDS], and encodes the set of vector lengths as 2660follows:: 2661 2662 __u64 vector_lengths[KVM_ARM64_SVE_VLS_WORDS]; 2663 2664 if (vq >= SVE_VQ_MIN && vq <= SVE_VQ_MAX && 2665 ((vector_lengths[(vq - KVM_ARM64_SVE_VQ_MIN) / 64] >> 2666 ((vq - KVM_ARM64_SVE_VQ_MIN) % 64)) & 1)) 2667 /* Vector length vq * 16 bytes supported */ 2668 else 2669 /* Vector length vq * 16 bytes not supported */ 2670 2671.. [2] The maximum value vq for which the above condition is true is 2672 max_vq. This is the maximum vector length available to the guest on 2673 this vcpu, and determines which register slices are visible through 2674 this ioctl interface. 2675 2676(See Documentation/arch/arm64/sve.rst for an explanation of the "vq" 2677nomenclature.) 2678 2679KVM_REG_ARM64_SVE_VLS is only accessible after KVM_ARM_VCPU_INIT. 2680KVM_ARM_VCPU_INIT initialises it to the best set of vector lengths that 2681the host supports. 2682 2683Userspace may subsequently modify it if desired until the vcpu's SVE 2684configuration is finalized using KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE). 2685 2686Apart from simply removing all vector lengths from the host set that 2687exceed some value, support for arbitrarily chosen sets of vector lengths 2688is hardware-dependent and may not be available. Attempting to configure 2689an invalid set of vector lengths via KVM_SET_ONE_REG will fail with 2690EINVAL. 2691 2692After the vcpu's SVE configuration is finalized, further attempts to 2693write this register will fail with EPERM. 2694 2695arm64 bitmap feature firmware pseudo-registers have the following bit pattern:: 2696 2697 0x6030 0000 0016 <regno:16> 2698 2699The bitmap feature firmware registers exposes the hypercall services that 2700are available for userspace to configure. The set bits corresponds to the 2701services that are available for the guests to access. By default, KVM 2702sets all the supported bits during VM initialization. The userspace can 2703discover the available services via KVM_GET_ONE_REG, and write back the 2704bitmap corresponding to the features that it wishes guests to see via 2705KVM_SET_ONE_REG. 2706 2707Note: These registers are immutable once any of the vCPUs of the VM has 2708run at least once. A KVM_SET_ONE_REG in such a scenario will return 2709a -EBUSY to userspace. 2710 2711(See Documentation/virt/kvm/arm/hypercalls.rst for more details.) 2712 2713 2714MIPS registers are mapped using the lower 32 bits. The upper 16 of that is 2715the register group type: 2716 2717MIPS core registers (see above) have the following id bit patterns:: 2718 2719 0x7030 0000 0000 <reg:16> 2720 2721MIPS CP0 registers (see KVM_REG_MIPS_CP0_* above) have the following id bit 2722patterns depending on whether they're 32-bit or 64-bit registers:: 2723 2724 0x7020 0000 0001 00 <reg:5> <sel:3> (32-bit) 2725 0x7030 0000 0001 00 <reg:5> <sel:3> (64-bit) 2726 2727Note: KVM_REG_MIPS_CP0_ENTRYLO0 and KVM_REG_MIPS_CP0_ENTRYLO1 are the MIPS64 2728versions of the EntryLo registers regardless of the word size of the host 2729hardware, host kernel, guest, and whether XPA is present in the guest, i.e. 2730with the RI and XI bits (if they exist) in bits 63 and 62 respectively, and 2731the PFNX field starting at bit 30. 2732 2733MIPS MAARs (see KVM_REG_MIPS_CP0_MAAR(*) above) have the following id bit 2734patterns:: 2735 2736 0x7030 0000 0001 01 <reg:8> 2737 2738MIPS KVM control registers (see above) have the following id bit patterns:: 2739 2740 0x7030 0000 0002 <reg:16> 2741 2742MIPS FPU registers (see KVM_REG_MIPS_FPR_{32,64}() above) have the following 2743id bit patterns depending on the size of the register being accessed. They are 2744always accessed according to the current guest FPU mode (Status.FR and 2745Config5.FRE), i.e. as the guest would see them, and they become unpredictable 2746if the guest FPU mode is changed. MIPS SIMD Architecture (MSA) vector 2747registers (see KVM_REG_MIPS_VEC_128() above) have similar patterns as they 2748overlap the FPU registers:: 2749 2750 0x7020 0000 0003 00 <0:3> <reg:5> (32-bit FPU registers) 2751 0x7030 0000 0003 00 <0:3> <reg:5> (64-bit FPU registers) 2752 0x7040 0000 0003 00 <0:3> <reg:5> (128-bit MSA vector registers) 2753 2754MIPS FPU control registers (see KVM_REG_MIPS_FCR_{IR,CSR} above) have the 2755following id bit patterns:: 2756 2757 0x7020 0000 0003 01 <0:3> <reg:5> 2758 2759MIPS MSA control registers (see KVM_REG_MIPS_MSA_{IR,CSR} above) have the 2760following id bit patterns:: 2761 2762 0x7020 0000 0003 02 <0:3> <reg:5> 2763 2764RISC-V registers are mapped using the lower 32 bits. The upper 8 bits of 2765that is the register group type. 2766 2767RISC-V config registers are meant for configuring a Guest VCPU and it has 2768the following id bit patterns:: 2769 2770 0x8020 0000 01 <index into the kvm_riscv_config struct:24> (32bit Host) 2771 0x8030 0000 01 <index into the kvm_riscv_config struct:24> (64bit Host) 2772 2773Following are the RISC-V config registers: 2774 2775======================= ========= ============================================= 2776 Encoding Register Description 2777======================= ========= ============================================= 2778 0x80x0 0000 0100 0000 isa ISA feature bitmap of Guest VCPU 2779======================= ========= ============================================= 2780 2781The isa config register can be read anytime but can only be written before 2782a Guest VCPU runs. It will have ISA feature bits matching underlying host 2783set by default. 2784 2785RISC-V core registers represent the general execution state of a Guest VCPU 2786and it has the following id bit patterns:: 2787 2788 0x8020 0000 02 <index into the kvm_riscv_core struct:24> (32bit Host) 2789 0x8030 0000 02 <index into the kvm_riscv_core struct:24> (64bit Host) 2790 2791Following are the RISC-V core registers: 2792 2793======================= ========= ============================================= 2794 Encoding Register Description 2795======================= ========= ============================================= 2796 0x80x0 0000 0200 0000 regs.pc Program counter 2797 0x80x0 0000 0200 0001 regs.ra Return address 2798 0x80x0 0000 0200 0002 regs.sp Stack pointer 2799 0x80x0 0000 0200 0003 regs.gp Global pointer 2800 0x80x0 0000 0200 0004 regs.tp Task pointer 2801 0x80x0 0000 0200 0005 regs.t0 Caller saved register 0 2802 0x80x0 0000 0200 0006 regs.t1 Caller saved register 1 2803 0x80x0 0000 0200 0007 regs.t2 Caller saved register 2 2804 0x80x0 0000 0200 0008 regs.s0 Callee saved register 0 2805 0x80x0 0000 0200 0009 regs.s1 Callee saved register 1 2806 0x80x0 0000 0200 000a regs.a0 Function argument (or return value) 0 2807 0x80x0 0000 0200 000b regs.a1 Function argument (or return value) 1 2808 0x80x0 0000 0200 000c regs.a2 Function argument 2 2809 0x80x0 0000 0200 000d regs.a3 Function argument 3 2810 0x80x0 0000 0200 000e regs.a4 Function argument 4 2811 0x80x0 0000 0200 000f regs.a5 Function argument 5 2812 0x80x0 0000 0200 0010 regs.a6 Function argument 6 2813 0x80x0 0000 0200 0011 regs.a7 Function argument 7 2814 0x80x0 0000 0200 0012 regs.s2 Callee saved register 2 2815 0x80x0 0000 0200 0013 regs.s3 Callee saved register 3 2816 0x80x0 0000 0200 0014 regs.s4 Callee saved register 4 2817 0x80x0 0000 0200 0015 regs.s5 Callee saved register 5 2818 0x80x0 0000 0200 0016 regs.s6 Callee saved register 6 2819 0x80x0 0000 0200 0017 regs.s7 Callee saved register 7 2820 0x80x0 0000 0200 0018 regs.s8 Callee saved register 8 2821 0x80x0 0000 0200 0019 regs.s9 Callee saved register 9 2822 0x80x0 0000 0200 001a regs.s10 Callee saved register 10 2823 0x80x0 0000 0200 001b regs.s11 Callee saved register 11 2824 0x80x0 0000 0200 001c regs.t3 Caller saved register 3 2825 0x80x0 0000 0200 001d regs.t4 Caller saved register 4 2826 0x80x0 0000 0200 001e regs.t5 Caller saved register 5 2827 0x80x0 0000 0200 001f regs.t6 Caller saved register 6 2828 0x80x0 0000 0200 0020 mode Privilege mode (1 = S-mode or 0 = U-mode) 2829======================= ========= ============================================= 2830 2831RISC-V csr registers represent the supervisor mode control/status registers 2832of a Guest VCPU and it has the following id bit patterns:: 2833 2834 0x8020 0000 03 <index into the kvm_riscv_csr struct:24> (32bit Host) 2835 0x8030 0000 03 <index into the kvm_riscv_csr struct:24> (64bit Host) 2836 2837Following are the RISC-V csr registers: 2838 2839======================= ========= ============================================= 2840 Encoding Register Description 2841======================= ========= ============================================= 2842 0x80x0 0000 0300 0000 sstatus Supervisor status 2843 0x80x0 0000 0300 0001 sie Supervisor interrupt enable 2844 0x80x0 0000 0300 0002 stvec Supervisor trap vector base 2845 0x80x0 0000 0300 0003 sscratch Supervisor scratch register 2846 0x80x0 0000 0300 0004 sepc Supervisor exception program counter 2847 0x80x0 0000 0300 0005 scause Supervisor trap cause 2848 0x80x0 0000 0300 0006 stval Supervisor bad address or instruction 2849 0x80x0 0000 0300 0007 sip Supervisor interrupt pending 2850 0x80x0 0000 0300 0008 satp Supervisor address translation and protection 2851======================= ========= ============================================= 2852 2853RISC-V timer registers represent the timer state of a Guest VCPU and it has 2854the following id bit patterns:: 2855 2856 0x8030 0000 04 <index into the kvm_riscv_timer struct:24> 2857 2858Following are the RISC-V timer registers: 2859 2860======================= ========= ============================================= 2861 Encoding Register Description 2862======================= ========= ============================================= 2863 0x8030 0000 0400 0000 frequency Time base frequency (read-only) 2864 0x8030 0000 0400 0001 time Time value visible to Guest 2865 0x8030 0000 0400 0002 compare Time compare programmed by Guest 2866 0x8030 0000 0400 0003 state Time compare state (1 = ON or 0 = OFF) 2867======================= ========= ============================================= 2868 2869RISC-V F-extension registers represent the single precision floating point 2870state of a Guest VCPU and it has the following id bit patterns:: 2871 2872 0x8020 0000 05 <index into the __riscv_f_ext_state struct:24> 2873 2874Following are the RISC-V F-extension registers: 2875 2876======================= ========= ============================================= 2877 Encoding Register Description 2878======================= ========= ============================================= 2879 0x8020 0000 0500 0000 f[0] Floating point register 0 2880 ... 2881 0x8020 0000 0500 001f f[31] Floating point register 31 2882 0x8020 0000 0500 0020 fcsr Floating point control and status register 2883======================= ========= ============================================= 2884 2885RISC-V D-extension registers represent the double precision floating point 2886state of a Guest VCPU and it has the following id bit patterns:: 2887 2888 0x8020 0000 06 <index into the __riscv_d_ext_state struct:24> (fcsr) 2889 0x8030 0000 06 <index into the __riscv_d_ext_state struct:24> (non-fcsr) 2890 2891Following are the RISC-V D-extension registers: 2892 2893======================= ========= ============================================= 2894 Encoding Register Description 2895======================= ========= ============================================= 2896 0x8030 0000 0600 0000 f[0] Floating point register 0 2897 ... 2898 0x8030 0000 0600 001f f[31] Floating point register 31 2899 0x8020 0000 0600 0020 fcsr Floating point control and status register 2900======================= ========= ============================================= 2901 2902LoongArch registers are mapped using the lower 32 bits. The upper 16 bits of 2903that is the register group type. 2904 2905LoongArch csr registers are used to control guest cpu or get status of guest 2906cpu, and they have the following id bit patterns:: 2907 2908 0x9030 0000 0001 00 <reg:5> <sel:3> (64-bit) 2909 2910LoongArch KVM control registers are used to implement some new defined functions 2911such as set vcpu counter or reset vcpu, and they have the following id bit patterns:: 2912 2913 0x9030 0000 0002 <reg:16> 2914 2915x86 MSR registers have the following id bit patterns:: 2916 0x2030 0002 <msr number:32> 2917 2918Following are the KVM-defined registers for x86: 2919 2920======================= ========= ============================================= 2921 Encoding Register Description 2922======================= ========= ============================================= 2923 0x2030 0003 0000 0000 SSP Shadow Stack Pointer 2924======================= ========= ============================================= 2925 29264.69 KVM_GET_ONE_REG 2927-------------------- 2928 2929:Capability: KVM_CAP_ONE_REG 2930:Architectures: all 2931:Type: vcpu ioctl 2932:Parameters: struct kvm_one_reg (in and out) 2933:Returns: 0 on success, negative value on failure 2934 2935Errors include: 2936 2937 ======== ============================================================ 2938 ENOENT no such register 2939 EINVAL invalid register ID, or no such register or used with VMs in 2940 protected virtualization mode on s390 2941 EPERM (arm64) register access not allowed before vcpu finalization 2942 ======== ============================================================ 2943 2944(These error codes are indicative only: do not rely on a specific error 2945code being returned in a specific situation.) 2946 2947This ioctl allows to receive the value of a single register implemented 2948in a vcpu. The register to read is indicated by the "id" field of the 2949kvm_one_reg struct passed in. On success, the register value can be found 2950at the memory location pointed to by "addr". 2951 2952The list of registers accessible using this interface is identical to the 2953list in 4.68. 2954 2955 29564.70 KVM_KVMCLOCK_CTRL 2957---------------------- 2958 2959:Capability: KVM_CAP_KVMCLOCK_CTRL 2960:Architectures: Any that implement pvclocks (currently x86 only) 2961:Type: vcpu ioctl 2962:Parameters: None 2963:Returns: 0 on success, -1 on error 2964 2965This ioctl sets a flag accessible to the guest indicating that the specified 2966vCPU has been paused by the host userspace. 2967 2968The host will set a flag in the pvclock structure that is checked from the 2969soft lockup watchdog. The flag is part of the pvclock structure that is 2970shared between guest and host, specifically the second bit of the flags 2971field of the pvclock_vcpu_time_info structure. It will be set exclusively by 2972the host and read/cleared exclusively by the guest. The guest operation of 2973checking and clearing the flag must be an atomic operation so 2974load-link/store-conditional, or equivalent must be used. There are two cases 2975where the guest will clear the flag: when the soft lockup watchdog timer resets 2976itself or when a soft lockup is detected. This ioctl can be called any time 2977after pausing the vcpu, but before it is resumed. 2978 2979 29804.71 KVM_SIGNAL_MSI 2981------------------- 2982 2983:Capability: KVM_CAP_SIGNAL_MSI 2984:Architectures: x86 arm64 2985:Type: vm ioctl 2986:Parameters: struct kvm_msi (in) 2987:Returns: >0 on delivery, 0 if guest blocked the MSI, and -1 on error 2988 2989Directly inject a MSI message. Only valid with in-kernel irqchip that handles 2990MSI messages. 2991 2992:: 2993 2994 struct kvm_msi { 2995 __u32 address_lo; 2996 __u32 address_hi; 2997 __u32 data; 2998 __u32 flags; 2999 __u32 devid; 3000 __u8 pad[12]; 3001 }; 3002 3003flags: 3004 KVM_MSI_VALID_DEVID: devid contains a valid value. The per-VM 3005 KVM_CAP_MSI_DEVID capability advertises the requirement to provide 3006 the device ID. If this capability is not available, userspace 3007 should never set the KVM_MSI_VALID_DEVID flag as the ioctl might fail. 3008 3009If KVM_MSI_VALID_DEVID is set, devid contains a unique device identifier 3010for the device that wrote the MSI message. For PCI, this is usually a 3011BDF identifier in the lower 16 bits. 3012 3013On x86, address_hi is ignored unless the KVM_X2APIC_API_USE_32BIT_IDS 3014feature of KVM_CAP_X2APIC_API capability is enabled. If it is enabled, 3015address_hi bits 31-8 provide bits 31-8 of the destination id. Bits 7-0 of 3016address_hi must be zero. 3017 3018 30194.71 KVM_CREATE_PIT2 3020-------------------- 3021 3022:Capability: KVM_CAP_PIT2 3023:Architectures: x86 3024:Type: vm ioctl 3025:Parameters: struct kvm_pit_config (in) 3026:Returns: 0 on success, -1 on error 3027 3028Creates an in-kernel device model for the i8254 PIT. This call is only valid 3029after enabling in-kernel irqchip support via KVM_CREATE_IRQCHIP. The following 3030parameters have to be passed:: 3031 3032 struct kvm_pit_config { 3033 __u32 flags; 3034 __u32 pad[15]; 3035 }; 3036 3037Valid flags are:: 3038 3039 #define KVM_PIT_SPEAKER_DUMMY 1 /* emulate speaker port stub */ 3040 3041PIT timer interrupts may use a per-VM kernel thread for injection. If it 3042exists, this thread will have a name of the following pattern:: 3043 3044 kvm-pit/<owner-process-pid> 3045 3046When running a guest with elevated priorities, the scheduling parameters of 3047this thread may have to be adjusted accordingly. 3048 3049This IOCTL replaces the obsolete KVM_CREATE_PIT. 3050 3051 30524.72 KVM_GET_PIT2 3053----------------- 3054 3055:Capability: KVM_CAP_PIT_STATE2 3056:Architectures: x86 3057:Type: vm ioctl 3058:Parameters: struct kvm_pit_state2 (out) 3059:Returns: 0 on success, -1 on error 3060 3061Retrieves the state of the in-kernel PIT model. Only valid after 3062KVM_CREATE_PIT2. The state is returned in the following structure:: 3063 3064 struct kvm_pit_state2 { 3065 struct kvm_pit_channel_state channels[3]; 3066 __u32 flags; 3067 __u32 reserved[9]; 3068 }; 3069 3070Valid flags are:: 3071 3072 /* disable PIT in HPET legacy mode */ 3073 #define KVM_PIT_FLAGS_HPET_LEGACY 0x00000001 3074 /* speaker port data bit enabled */ 3075 #define KVM_PIT_FLAGS_SPEAKER_DATA_ON 0x00000002 3076 3077This IOCTL replaces the obsolete KVM_GET_PIT. 3078 3079 30804.73 KVM_SET_PIT2 3081----------------- 3082 3083:Capability: KVM_CAP_PIT_STATE2 3084:Architectures: x86 3085:Type: vm ioctl 3086:Parameters: struct kvm_pit_state2 (in) 3087:Returns: 0 on success, -1 on error 3088 3089Sets the state of the in-kernel PIT model. Only valid after KVM_CREATE_PIT2. 3090See KVM_GET_PIT2 for details on struct kvm_pit_state2. 3091 3092.. Tip:: 3093 ``KVM_SET_PIT2`` strictly adheres to the spec of Intel 8254 PIT. For example, 3094 a ``count`` value of 0 in ``struct kvm_pit_channel_state`` is interpreted as 3095 65536, which is the maximum count value. Refer to `Intel 8254 programmable 3096 interval timer <https://www.scs.stanford.edu/10wi-cs140/pintos/specs/8254.pdf>`_. 3097 3098This IOCTL replaces the obsolete KVM_SET_PIT. 3099 3100 31014.74 KVM_PPC_GET_SMMU_INFO 3102-------------------------- 3103 3104:Capability: KVM_CAP_PPC_GET_SMMU_INFO 3105:Architectures: powerpc 3106:Type: vm ioctl 3107:Parameters: None 3108:Returns: 0 on success, -1 on error 3109 3110This populates and returns a structure describing the features of 3111the "Server" class MMU emulation supported by KVM. 3112This can in turn be used by userspace to generate the appropriate 3113device-tree properties for the guest operating system. 3114 3115The structure contains some global information, followed by an 3116array of supported segment page sizes:: 3117 3118 struct kvm_ppc_smmu_info { 3119 __u64 flags; 3120 __u32 slb_size; 3121 __u32 pad; 3122 struct kvm_ppc_one_seg_page_size sps[KVM_PPC_PAGE_SIZES_MAX_SZ]; 3123 }; 3124 3125The supported flags are: 3126 3127 - KVM_PPC_PAGE_SIZES_REAL: 3128 When that flag is set, guest page sizes must "fit" the backing 3129 store page sizes. When not set, any page size in the list can 3130 be used regardless of how they are backed by userspace. 3131 3132 - KVM_PPC_1T_SEGMENTS 3133 The emulated MMU supports 1T segments in addition to the 3134 standard 256M ones. 3135 3136 - KVM_PPC_NO_HASH 3137 This flag indicates that HPT guests are not supported by KVM, 3138 thus all guests must use radix MMU mode. 3139 3140The "slb_size" field indicates how many SLB entries are supported 3141 3142The "sps" array contains 8 entries indicating the supported base 3143page sizes for a segment in increasing order. Each entry is defined 3144as follow:: 3145 3146 struct kvm_ppc_one_seg_page_size { 3147 __u32 page_shift; /* Base page shift of segment (or 0) */ 3148 __u32 slb_enc; /* SLB encoding for BookS */ 3149 struct kvm_ppc_one_page_size enc[KVM_PPC_PAGE_SIZES_MAX_SZ]; 3150 }; 3151 3152An entry with a "page_shift" of 0 is unused. Because the array is 3153organized in increasing order, a lookup can stop when encountering 3154such an entry. 3155 3156The "slb_enc" field provides the encoding to use in the SLB for the 3157page size. The bits are in positions such as the value can directly 3158be OR'ed into the "vsid" argument of the slbmte instruction. 3159 3160The "enc" array is a list which for each of those segment base page 3161size provides the list of supported actual page sizes (which can be 3162only larger or equal to the base page size), along with the 3163corresponding encoding in the hash PTE. Similarly, the array is 31648 entries sorted by increasing sizes and an entry with a "0" shift 3165is an empty entry and a terminator:: 3166 3167 struct kvm_ppc_one_page_size { 3168 __u32 page_shift; /* Page shift (or 0) */ 3169 __u32 pte_enc; /* Encoding in the HPTE (>>12) */ 3170 }; 3171 3172The "pte_enc" field provides a value that can OR'ed into the hash 3173PTE's RPN field (ie, it needs to be shifted left by 12 to OR it 3174into the hash PTE second double word). 3175 31764.75 KVM_IRQFD 3177-------------- 3178 3179:Capability: KVM_CAP_IRQFD 3180:Architectures: x86 s390 arm64 3181:Type: vm ioctl 3182:Parameters: struct kvm_irqfd (in) 3183:Returns: 0 on success, -1 on error 3184 3185Allows setting an eventfd to directly trigger a guest interrupt. 3186kvm_irqfd.fd specifies the file descriptor to use as the eventfd and 3187kvm_irqfd.gsi specifies the irqchip pin toggled by this event. When 3188an event is triggered on the eventfd, an interrupt is injected into 3189the guest using the specified gsi pin. The irqfd is removed using 3190the KVM_IRQFD_FLAG_DEASSIGN flag, specifying both kvm_irqfd.fd 3191and kvm_irqfd.gsi. 3192 3193With KVM_CAP_IRQFD_RESAMPLE, KVM_IRQFD supports a de-assert and notify 3194mechanism allowing emulation of level-triggered, irqfd-based 3195interrupts. When KVM_IRQFD_FLAG_RESAMPLE is set the user must pass an 3196additional eventfd in the kvm_irqfd.resamplefd field. When operating 3197in resample mode, posting of an interrupt through kvm_irq.fd asserts 3198the specified gsi in the irqchip. When the irqchip is resampled, such 3199as from an EOI, the gsi is de-asserted and the user is notified via 3200kvm_irqfd.resamplefd. It is the user's responsibility to re-queue 3201the interrupt if the device making use of it still requires service. 3202Note that closing the resamplefd is not sufficient to disable the 3203irqfd. The KVM_IRQFD_FLAG_RESAMPLE is only necessary on assignment 3204and need not be specified with KVM_IRQFD_FLAG_DEASSIGN. 3205 3206On arm64, gsi routing being supported, the following can happen: 3207 3208- in case no routing entry is associated to this gsi, injection fails 3209- in case the gsi is associated to an irqchip routing entry, 3210 irqchip.pin + 32 corresponds to the injected SPI ID. 3211- in case the gsi is associated to an MSI routing entry, the MSI 3212 message and device ID are translated into an LPI (support restricted 3213 to GICv3 ITS in-kernel emulation). 3214 32154.76 KVM_PPC_ALLOCATE_HTAB 3216-------------------------- 3217 3218:Capability: KVM_CAP_PPC_ALLOC_HTAB 3219:Architectures: powerpc 3220:Type: vm ioctl 3221:Parameters: Pointer to u32 containing hash table order (in/out) 3222:Returns: 0 on success, -1 on error 3223 3224This requests the host kernel to allocate an MMU hash table for a 3225guest using the PAPR paravirtualization interface. This only does 3226anything if the kernel is configured to use the Book 3S HV style of 3227virtualization. Otherwise the capability doesn't exist and the ioctl 3228returns an ENOTTY error. The rest of this description assumes Book 3S 3229HV. 3230 3231There must be no vcpus running when this ioctl is called; if there 3232are, it will do nothing and return an EBUSY error. 3233 3234The parameter is a pointer to a 32-bit unsigned integer variable 3235containing the order (log base 2) of the desired size of the hash 3236table, which must be between 18 and 46. On successful return from the 3237ioctl, the value will not be changed by the kernel. 3238 3239If no hash table has been allocated when any vcpu is asked to run 3240(with the KVM_RUN ioctl), the host kernel will allocate a 3241default-sized hash table (16 MB). 3242 3243If this ioctl is called when a hash table has already been allocated, 3244with a different order from the existing hash table, the existing hash 3245table will be freed and a new one allocated. If this is ioctl is 3246called when a hash table has already been allocated of the same order 3247as specified, the kernel will clear out the existing hash table (zero 3248all HPTEs). In either case, if the guest is using the virtualized 3249real-mode area (VRMA) facility, the kernel will re-create the VMRA 3250HPTEs on the next KVM_RUN of any vcpu. 3251 32524.77 KVM_S390_INTERRUPT 3253----------------------- 3254 3255:Capability: basic 3256:Architectures: s390 3257:Type: vm ioctl, vcpu ioctl 3258:Parameters: struct kvm_s390_interrupt (in) 3259:Returns: 0 on success, -1 on error 3260 3261Allows to inject an interrupt to the guest. Interrupts can be floating 3262(vm ioctl) or per cpu (vcpu ioctl), depending on the interrupt type. 3263 3264Interrupt parameters are passed via kvm_s390_interrupt:: 3265 3266 struct kvm_s390_interrupt { 3267 __u32 type; 3268 __u32 parm; 3269 __u64 parm64; 3270 }; 3271 3272type can be one of the following: 3273 3274KVM_S390_SIGP_STOP (vcpu) 3275 - sigp stop; optional flags in parm 3276KVM_S390_PROGRAM_INT (vcpu) 3277 - program check; code in parm 3278KVM_S390_SIGP_SET_PREFIX (vcpu) 3279 - sigp set prefix; prefix address in parm 3280KVM_S390_RESTART (vcpu) 3281 - restart 3282KVM_S390_INT_CLOCK_COMP (vcpu) 3283 - clock comparator interrupt 3284KVM_S390_INT_CPU_TIMER (vcpu) 3285 - CPU timer interrupt 3286KVM_S390_INT_VIRTIO (vm) 3287 - virtio external interrupt; external interrupt 3288 parameters in parm and parm64 3289KVM_S390_INT_SERVICE (vm) 3290 - sclp external interrupt; sclp parameter in parm 3291KVM_S390_INT_EMERGENCY (vcpu) 3292 - sigp emergency; source cpu in parm 3293KVM_S390_INT_EXTERNAL_CALL (vcpu) 3294 - sigp external call; source cpu in parm 3295KVM_S390_INT_IO(ai,cssid,ssid,schid) (vm) 3296 - compound value to indicate an 3297 I/O interrupt (ai - adapter interrupt; cssid,ssid,schid - subchannel); 3298 I/O interruption parameters in parm (subchannel) and parm64 (intparm, 3299 interruption subclass) 3300KVM_S390_MCHK (vm, vcpu) 3301 - machine check interrupt; cr 14 bits in parm, machine check interrupt 3302 code in parm64 (note that machine checks needing further payload are not 3303 supported by this ioctl) 3304 3305This is an asynchronous vcpu ioctl and can be invoked from any thread. 3306 33074.78 KVM_PPC_GET_HTAB_FD 3308------------------------ 3309 3310:Capability: KVM_CAP_PPC_HTAB_FD 3311:Architectures: powerpc 3312:Type: vm ioctl 3313:Parameters: Pointer to struct kvm_get_htab_fd (in) 3314:Returns: file descriptor number (>= 0) on success, -1 on error 3315 3316This returns a file descriptor that can be used either to read out the 3317entries in the guest's hashed page table (HPT), or to write entries to 3318initialize the HPT. The returned fd can only be written to if the 3319KVM_GET_HTAB_WRITE bit is set in the flags field of the argument, and 3320can only be read if that bit is clear. The argument struct looks like 3321this:: 3322 3323 /* For KVM_PPC_GET_HTAB_FD */ 3324 struct kvm_get_htab_fd { 3325 __u64 flags; 3326 __u64 start_index; 3327 __u64 reserved[2]; 3328 }; 3329 3330 /* Values for kvm_get_htab_fd.flags */ 3331 #define KVM_GET_HTAB_BOLTED_ONLY ((__u64)0x1) 3332 #define KVM_GET_HTAB_WRITE ((__u64)0x2) 3333 3334The 'start_index' field gives the index in the HPT of the entry at 3335which to start reading. It is ignored when writing. 3336 3337Reads on the fd will initially supply information about all 3338"interesting" HPT entries. Interesting entries are those with the 3339bolted bit set, if the KVM_GET_HTAB_BOLTED_ONLY bit is set, otherwise 3340all entries. When the end of the HPT is reached, the read() will 3341return. If read() is called again on the fd, it will start again from 3342the beginning of the HPT, but will only return HPT entries that have 3343changed since they were last read. 3344 3345Data read or written is structured as a header (8 bytes) followed by a 3346series of valid HPT entries (16 bytes) each. The header indicates how 3347many valid HPT entries there are and how many invalid entries follow 3348the valid entries. The invalid entries are not represented explicitly 3349in the stream. The header format is:: 3350 3351 struct kvm_get_htab_header { 3352 __u32 index; 3353 __u16 n_valid; 3354 __u16 n_invalid; 3355 }; 3356 3357Writes to the fd create HPT entries starting at the index given in the 3358header; first 'n_valid' valid entries with contents from the data 3359written, then 'n_invalid' invalid entries, invalidating any previously 3360valid entries found. 3361 33624.79 KVM_CREATE_DEVICE 3363---------------------- 3364 3365:Capability: KVM_CAP_DEVICE_CTRL 3366:Architectures: all 3367:Type: vm ioctl 3368:Parameters: struct kvm_create_device (in/out) 3369:Returns: 0 on success, -1 on error 3370 3371Errors: 3372 3373 ====== ======================================================= 3374 ENODEV The device type is unknown or unsupported 3375 EEXIST Device already created, and this type of device may not 3376 be instantiated multiple times 3377 ====== ======================================================= 3378 3379 Other error conditions may be defined by individual device types or 3380 have their standard meanings. 3381 3382Creates an emulated device in the kernel. The file descriptor returned 3383in fd can be used with KVM_SET/GET/HAS_DEVICE_ATTR. 3384 3385If the KVM_CREATE_DEVICE_TEST flag is set, only test whether the 3386device type is supported (not necessarily whether it can be created 3387in the current vm). 3388 3389Individual devices should not define flags. Attributes should be used 3390for specifying any behavior that is not implied by the device type 3391number. 3392 3393:: 3394 3395 struct kvm_create_device { 3396 __u32 type; /* in: KVM_DEV_TYPE_xxx */ 3397 __u32 fd; /* out: device handle */ 3398 __u32 flags; /* in: KVM_CREATE_DEVICE_xxx */ 3399 }; 3400 34014.80 KVM_SET_DEVICE_ATTR/KVM_GET_DEVICE_ATTR 3402-------------------------------------------- 3403 3404:Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device, 3405 KVM_CAP_VCPU_ATTRIBUTES for vcpu device 3406 KVM_CAP_SYS_ATTRIBUTES for system (/dev/kvm) device (no set) 3407:Architectures: x86, arm64, s390 3408:Type: device ioctl, vm ioctl, vcpu ioctl 3409:Parameters: struct kvm_device_attr 3410:Returns: 0 on success, -1 on error 3411 3412Errors: 3413 3414 ===== ============================================================= 3415 ENXIO The group or attribute is unknown/unsupported for this device 3416 or hardware support is missing. 3417 EPERM The attribute cannot (currently) be accessed this way 3418 (e.g. read-only attribute, or attribute that only makes 3419 sense when the device is in a different state) 3420 ===== ============================================================= 3421 3422 Other error conditions may be defined by individual device types. 3423 3424Gets/sets a specified piece of device configuration and/or state. The 3425semantics are device-specific. See individual device documentation in 3426the "devices" directory. As with ONE_REG, the size of the data 3427transferred is defined by the particular attribute. 3428 3429:: 3430 3431 struct kvm_device_attr { 3432 __u32 flags; /* no flags currently defined */ 3433 __u32 group; /* device-defined */ 3434 __u64 attr; /* group-defined */ 3435 __u64 addr; /* userspace address of attr data */ 3436 }; 3437 34384.81 KVM_HAS_DEVICE_ATTR 3439------------------------ 3440 3441:Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device, 3442 KVM_CAP_VCPU_ATTRIBUTES for vcpu device 3443 KVM_CAP_SYS_ATTRIBUTES for system (/dev/kvm) device 3444:Type: device ioctl, vm ioctl, vcpu ioctl 3445:Parameters: struct kvm_device_attr 3446:Returns: 0 on success, -1 on error 3447 3448Errors: 3449 3450 ===== ============================================================= 3451 ENXIO The group or attribute is unknown/unsupported for this device 3452 or hardware support is missing. 3453 ===== ============================================================= 3454 3455Tests whether a device supports a particular attribute. A successful 3456return indicates the attribute is implemented. It does not necessarily 3457indicate that the attribute can be read or written in the device's 3458current state. "addr" is ignored. 3459 3460.. _KVM_ARM_VCPU_INIT: 3461 34624.82 KVM_ARM_VCPU_INIT 3463---------------------- 3464 3465:Capability: basic 3466:Architectures: arm64 3467:Type: vcpu ioctl 3468:Parameters: struct kvm_vcpu_init (in) 3469:Returns: 0 on success; -1 on error 3470 3471Errors: 3472 3473 ====== ================================================================= 3474 EINVAL the target is unknown, or the combination of features is invalid. 3475 ENOENT a features bit specified is unknown. 3476 ====== ================================================================= 3477 3478This tells KVM what type of CPU to present to the guest, and what 3479optional features it should have. This will cause a reset of the cpu 3480registers to their initial values. If this is not called, KVM_RUN will 3481return ENOEXEC for that vcpu. 3482 3483The initial values are defined as: 3484 - Processor state: 3485 * AArch64: EL1h, D, A, I and F bits set. All other bits 3486 are cleared. 3487 * AArch32: SVC, A, I and F bits set. All other bits are 3488 cleared. 3489 - General Purpose registers, including PC and SP: set to 0 3490 - FPSIMD/NEON registers: set to 0 3491 - SVE registers: set to 0 3492 - System registers: Reset to their architecturally defined 3493 values as for a warm reset to EL1 (resp. SVC) or EL2 (in the 3494 case of EL2 being enabled). 3495 3496Note that because some registers reflect machine topology, all vcpus 3497should be created before this ioctl is invoked. 3498 3499Userspace can call this function multiple times for a given vcpu, including 3500after the vcpu has been run. This will reset the vcpu to its initial 3501state. All calls to this function after the initial call must use the same 3502target and same set of feature flags, otherwise EINVAL will be returned. 3503 3504Possible features: 3505 3506 - KVM_ARM_VCPU_POWER_OFF: Starts the CPU in a power-off state. 3507 Depends on KVM_CAP_ARM_PSCI. If not set, the CPU will be powered on 3508 and execute guest code when KVM_RUN is called. 3509 - KVM_ARM_VCPU_EL1_32BIT: Starts the CPU in a 32bit mode. 3510 Depends on KVM_CAP_ARM_EL1_32BIT (arm64 only). 3511 - KVM_ARM_VCPU_PSCI_0_2: Emulate PSCI v0.2 (or a future revision 3512 backward compatible with v0.2) for the CPU. 3513 Depends on KVM_CAP_ARM_PSCI_0_2. 3514 - KVM_ARM_VCPU_PMU_V3: Emulate PMUv3 for the CPU. 3515 Depends on KVM_CAP_ARM_PMU_V3. 3516 3517 - KVM_ARM_VCPU_PTRAUTH_ADDRESS: Enables Address Pointer authentication 3518 for arm64 only. 3519 Depends on KVM_CAP_ARM_PTRAUTH_ADDRESS. 3520 If KVM_CAP_ARM_PTRAUTH_ADDRESS and KVM_CAP_ARM_PTRAUTH_GENERIC are 3521 both present, then both KVM_ARM_VCPU_PTRAUTH_ADDRESS and 3522 KVM_ARM_VCPU_PTRAUTH_GENERIC must be requested or neither must be 3523 requested. 3524 3525 - KVM_ARM_VCPU_PTRAUTH_GENERIC: Enables Generic Pointer authentication 3526 for arm64 only. 3527 Depends on KVM_CAP_ARM_PTRAUTH_GENERIC. 3528 If KVM_CAP_ARM_PTRAUTH_ADDRESS and KVM_CAP_ARM_PTRAUTH_GENERIC are 3529 both present, then both KVM_ARM_VCPU_PTRAUTH_ADDRESS and 3530 KVM_ARM_VCPU_PTRAUTH_GENERIC must be requested or neither must be 3531 requested. 3532 3533 - KVM_ARM_VCPU_SVE: Enables SVE for the CPU (arm64 only). 3534 Depends on KVM_CAP_ARM_SVE. 3535 Requires KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): 3536 3537 * After KVM_ARM_VCPU_INIT: 3538 3539 - KVM_REG_ARM64_SVE_VLS may be read using KVM_GET_ONE_REG: the 3540 initial value of this pseudo-register indicates the best set of 3541 vector lengths possible for a vcpu on this host. 3542 3543 * Before KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): 3544 3545 - KVM_RUN and KVM_GET_REG_LIST are not available; 3546 3547 - KVM_GET_ONE_REG and KVM_SET_ONE_REG cannot be used to access 3548 the scalable architectural SVE registers 3549 KVM_REG_ARM64_SVE_ZREG(), KVM_REG_ARM64_SVE_PREG() or 3550 KVM_REG_ARM64_SVE_FFR; 3551 3552 - KVM_REG_ARM64_SVE_VLS may optionally be written using 3553 KVM_SET_ONE_REG, to modify the set of vector lengths available 3554 for the vcpu. 3555 3556 * After KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): 3557 3558 - the KVM_REG_ARM64_SVE_VLS pseudo-register is immutable, and can 3559 no longer be written using KVM_SET_ONE_REG. 3560 3561 - KVM_ARM_VCPU_HAS_EL2: Enable Nested Virtualisation support, 3562 booting the guest from EL2 instead of EL1. 3563 Depends on KVM_CAP_ARM_EL2. 3564 The VM is running with HCR_EL2.E2H being RES1 (VHE) unless 3565 KVM_ARM_VCPU_HAS_EL2_E2H0 is also set. 3566 3567 - KVM_ARM_VCPU_HAS_EL2_E2H0: Restrict Nested Virtualisation 3568 support to HCR_EL2.E2H being RES0 (non-VHE). 3569 Depends on KVM_CAP_ARM_EL2_E2H0. 3570 KVM_ARM_VCPU_HAS_EL2 must also be set. 3571 35724.83 KVM_ARM_PREFERRED_TARGET 3573----------------------------- 3574 3575:Capability: basic 3576:Architectures: arm64 3577:Type: vm ioctl 3578:Parameters: struct kvm_vcpu_init (out) 3579:Returns: 0 on success; -1 on error 3580 3581Errors: 3582 3583 ====== ========================================== 3584 ENODEV no preferred target available for the host 3585 ====== ========================================== 3586 3587This queries KVM for preferred CPU target type which can be emulated 3588by KVM on underlying host. 3589 3590The ioctl returns struct kvm_vcpu_init instance containing information 3591about preferred CPU target type and recommended features for it. The 3592kvm_vcpu_init->features bitmap returned will have feature bits set if 3593the preferred target recommends setting these features, but this is 3594not mandatory. 3595 3596The information returned by this ioctl can be used to prepare an instance 3597of struct kvm_vcpu_init for KVM_ARM_VCPU_INIT ioctl which will result in 3598VCPU matching underlying host. 3599 3600 36014.84 KVM_GET_REG_LIST 3602--------------------- 3603 3604:Capability: basic 3605:Architectures: arm64, mips, riscv, x86 (if KVM_CAP_ONE_REG) 3606:Type: vcpu ioctl 3607:Parameters: struct kvm_reg_list (in/out) 3608:Returns: 0 on success; -1 on error 3609 3610Errors: 3611 3612 ===== ============================================================== 3613 E2BIG the reg index list is too big to fit in the array specified by 3614 the user (the number required will be written into n). 3615 ===== ============================================================== 3616 3617:: 3618 3619 struct kvm_reg_list { 3620 __u64 n; /* number of registers in reg[] */ 3621 __u64 reg[0]; 3622 }; 3623 3624This ioctl returns the guest registers that are supported for the 3625KVM_GET_ONE_REG/KVM_SET_ONE_REG calls. 3626 3627Note that s390 does not support KVM_GET_REG_LIST for historical reasons 3628(read: nobody cared). The set of registers in kernels 4.x and newer is: 3629 3630- KVM_REG_S390_TODPR 3631 3632- KVM_REG_S390_EPOCHDIFF 3633 3634- KVM_REG_S390_CPU_TIMER 3635 3636- KVM_REG_S390_CLOCK_COMP 3637 3638- KVM_REG_S390_PFTOKEN 3639 3640- KVM_REG_S390_PFCOMPARE 3641 3642- KVM_REG_S390_PFSELECT 3643 3644- KVM_REG_S390_PP 3645 3646- KVM_REG_S390_GBEA 3647 3648Note, for x86, all MSRs enumerated by KVM_GET_MSR_INDEX_LIST are supported as 3649type KVM_X86_REG_TYPE_MSR, but are NOT enumerated via KVM_GET_REG_LIST. 3650 36514.85 KVM_ARM_SET_DEVICE_ADDR (deprecated) 3652----------------------------------------- 3653 3654:Capability: KVM_CAP_ARM_SET_DEVICE_ADDR 3655:Architectures: arm64 3656:Type: vm ioctl 3657:Parameters: struct kvm_arm_device_address (in) 3658:Returns: 0 on success, -1 on error 3659 3660Errors: 3661 3662 ====== ============================================ 3663 ENODEV The device id is unknown 3664 ENXIO Device not supported on current system 3665 EEXIST Address already set 3666 E2BIG Address outside guest physical address space 3667 EBUSY Address overlaps with other device range 3668 ====== ============================================ 3669 3670:: 3671 3672 struct kvm_arm_device_addr { 3673 __u64 id; 3674 __u64 addr; 3675 }; 3676 3677Specify a device address in the guest's physical address space where guests 3678can access emulated or directly exposed devices, which the host kernel needs 3679to know about. The id field is an architecture specific identifier for a 3680specific device. 3681 3682arm64 divides the id field into two parts, a device id and an 3683address type id specific to the individual device:: 3684 3685 bits: | 63 ... 32 | 31 ... 16 | 15 ... 0 | 3686 field: | 0x00000000 | device id | addr type id | 3687 3688arm64 currently only require this when using the in-kernel GIC 3689support for the hardware VGIC features, using KVM_ARM_DEVICE_VGIC_V2 3690as the device id. When setting the base address for the guest's 3691mapping of the VGIC virtual CPU and distributor interface, the ioctl 3692must be called after calling KVM_CREATE_IRQCHIP, but before calling 3693KVM_RUN on any of the VCPUs. Calling this ioctl twice for any of the 3694base addresses will return -EEXIST. 3695 3696Note, this IOCTL is deprecated and the more flexible SET/GET_DEVICE_ATTR API 3697should be used instead. 3698 3699 37004.86 KVM_PPC_RTAS_DEFINE_TOKEN 3701------------------------------ 3702 3703:Capability: KVM_CAP_PPC_RTAS 3704:Architectures: ppc 3705:Type: vm ioctl 3706:Parameters: struct kvm_rtas_token_args 3707:Returns: 0 on success, -1 on error 3708 3709Defines a token value for a RTAS (Run Time Abstraction Services) 3710service in order to allow it to be handled in the kernel. The 3711argument struct gives the name of the service, which must be the name 3712of a service that has a kernel-side implementation. If the token 3713value is non-zero, it will be associated with that service, and 3714subsequent RTAS calls by the guest specifying that token will be 3715handled by the kernel. If the token value is 0, then any token 3716associated with the service will be forgotten, and subsequent RTAS 3717calls by the guest for that service will be passed to userspace to be 3718handled. 3719 37204.87 KVM_SET_GUEST_DEBUG 3721------------------------ 3722 3723:Capability: KVM_CAP_SET_GUEST_DEBUG 3724:Architectures: x86, s390, ppc, arm64 3725:Type: vcpu ioctl 3726:Parameters: struct kvm_guest_debug (in) 3727:Returns: 0 on success; -1 on error 3728 3729:: 3730 3731 struct kvm_guest_debug { 3732 __u32 control; 3733 __u32 pad; 3734 struct kvm_guest_debug_arch arch; 3735 }; 3736 3737Set up the processor specific debug registers and configure vcpu for 3738handling guest debug events. There are two parts to the structure, the 3739first a control bitfield indicates the type of debug events to handle 3740when running. Common control bits are: 3741 3742 - KVM_GUESTDBG_ENABLE: guest debugging is enabled 3743 - KVM_GUESTDBG_SINGLESTEP: the next run should single-step 3744 3745The top 16 bits of the control field are architecture specific control 3746flags which can include the following: 3747 3748 - KVM_GUESTDBG_USE_SW_BP: using software breakpoints [x86, arm64] 3749 - KVM_GUESTDBG_USE_HW_BP: using hardware breakpoints [x86, s390] 3750 - KVM_GUESTDBG_USE_HW: using hardware debug events [arm64] 3751 - KVM_GUESTDBG_INJECT_DB: inject DB type exception [x86] 3752 - KVM_GUESTDBG_INJECT_BP: inject BP type exception [x86] 3753 - KVM_GUESTDBG_EXIT_PENDING: trigger an immediate guest exit [s390] 3754 - KVM_GUESTDBG_BLOCKIRQ: avoid injecting interrupts/NMI/SMI [x86] 3755 3756For example KVM_GUESTDBG_USE_SW_BP indicates that software breakpoints 3757are enabled in memory so we need to ensure breakpoint exceptions are 3758correctly trapped and the KVM run loop exits at the breakpoint and not 3759running off into the normal guest vector. For KVM_GUESTDBG_USE_HW_BP 3760we need to ensure the guest vCPUs architecture specific registers are 3761updated to the correct (supplied) values. 3762 3763The second part of the structure is architecture specific and 3764typically contains a set of debug registers. 3765 3766For arm64 the number of debug registers is implementation defined and 3767can be determined by querying the KVM_CAP_GUEST_DEBUG_HW_BPS and 3768KVM_CAP_GUEST_DEBUG_HW_WPS capabilities which return a positive number 3769indicating the number of supported registers. 3770 3771For ppc, the KVM_CAP_PPC_GUEST_DEBUG_SSTEP capability indicates whether 3772the single-step debug event (KVM_GUESTDBG_SINGLESTEP) is supported. 3773 3774Also when supported, KVM_CAP_SET_GUEST_DEBUG2 capability indicates the 3775supported KVM_GUESTDBG_* bits in the control field. 3776 3777When debug events exit the main run loop with the reason 3778KVM_EXIT_DEBUG with the kvm_debug_exit_arch part of the kvm_run 3779structure containing architecture specific debug information. 3780 37814.88 KVM_GET_EMULATED_CPUID 3782--------------------------- 3783 3784:Capability: KVM_CAP_EXT_EMUL_CPUID 3785:Architectures: x86 3786:Type: system ioctl 3787:Parameters: struct kvm_cpuid2 (in/out) 3788:Returns: 0 on success, -1 on error 3789 3790:: 3791 3792 struct kvm_cpuid2 { 3793 __u32 nent; 3794 __u32 flags; 3795 struct kvm_cpuid_entry2 entries[0]; 3796 }; 3797 3798The member 'flags' is used for passing flags from userspace. 3799 3800:: 3801 3802 #define KVM_CPUID_FLAG_SIGNIFCANT_INDEX BIT(0) 3803 #define KVM_CPUID_FLAG_STATEFUL_FUNC BIT(1) /* deprecated */ 3804 #define KVM_CPUID_FLAG_STATE_READ_NEXT BIT(2) /* deprecated */ 3805 3806 struct kvm_cpuid_entry2 { 3807 __u32 function; 3808 __u32 index; 3809 __u32 flags; 3810 __u32 eax; 3811 __u32 ebx; 3812 __u32 ecx; 3813 __u32 edx; 3814 __u32 padding[3]; 3815 }; 3816 3817This ioctl returns x86 cpuid features which are emulated by 3818kvm.Userspace can use the information returned by this ioctl to query 3819which features are emulated by kvm instead of being present natively. 3820 3821Userspace invokes KVM_GET_EMULATED_CPUID by passing a kvm_cpuid2 3822structure with the 'nent' field indicating the number of entries in 3823the variable-size array 'entries'. If the number of entries is too low 3824to describe the cpu capabilities, an error (E2BIG) is returned. If the 3825number is too high, the 'nent' field is adjusted and an error (ENOMEM) 3826is returned. If the number is just right, the 'nent' field is adjusted 3827to the number of valid entries in the 'entries' array, which is then 3828filled. 3829 3830The entries returned are the set CPUID bits of the respective features 3831which kvm emulates, as returned by the CPUID instruction, with unknown 3832or unsupported feature bits cleared. 3833 3834Features like x2apic, for example, may not be present in the host cpu 3835but are exposed by kvm in KVM_GET_SUPPORTED_CPUID because they can be 3836emulated efficiently and thus not included here. 3837 3838The fields in each entry are defined as follows: 3839 3840 function: 3841 the eax value used to obtain the entry 3842 index: 3843 the ecx value used to obtain the entry (for entries that are 3844 affected by ecx) 3845 flags: 3846 an OR of zero or more of the following: 3847 3848 KVM_CPUID_FLAG_SIGNIFCANT_INDEX: 3849 if the index field is valid 3850 3851 eax, ebx, ecx, edx: 3852 3853 the values returned by the cpuid instruction for 3854 this function/index combination 3855 38564.89 KVM_S390_MEM_OP 3857-------------------- 3858 3859:Capability: KVM_CAP_S390_MEM_OP, KVM_CAP_S390_PROTECTED, KVM_CAP_S390_MEM_OP_EXTENSION 3860:Architectures: s390 3861:Type: vm ioctl, vcpu ioctl 3862:Parameters: struct kvm_s390_mem_op (in) 3863:Returns: = 0 on success, 3864 < 0 on generic error (e.g. -EFAULT or -ENOMEM), 3865 16 bit program exception code if the access causes such an exception 3866 3867Read or write data from/to the VM's memory. 3868The KVM_CAP_S390_MEM_OP_EXTENSION capability specifies what functionality is 3869supported. 3870 3871Parameters are specified via the following structure:: 3872 3873 struct kvm_s390_mem_op { 3874 __u64 gaddr; /* the guest address */ 3875 __u64 flags; /* flags */ 3876 __u32 size; /* amount of bytes */ 3877 __u32 op; /* type of operation */ 3878 __u64 buf; /* buffer in userspace */ 3879 union { 3880 struct { 3881 __u8 ar; /* the access register number */ 3882 __u8 key; /* access key, ignored if flag unset */ 3883 __u8 pad1[6]; /* ignored */ 3884 __u64 old_addr; /* ignored if flag unset */ 3885 }; 3886 __u32 sida_offset; /* offset into the sida */ 3887 __u8 reserved[32]; /* ignored */ 3888 }; 3889 }; 3890 3891The start address of the memory region has to be specified in the "gaddr" 3892field, and the length of the region in the "size" field (which must not 3893be 0). The maximum value for "size" can be obtained by checking the 3894KVM_CAP_S390_MEM_OP capability. "buf" is the buffer supplied by the 3895userspace application where the read data should be written to for 3896a read access, or where the data that should be written is stored for 3897a write access. The "reserved" field is meant for future extensions. 3898Reserved and unused values are ignored. Future extension that add members must 3899introduce new flags. 3900 3901The type of operation is specified in the "op" field. Flags modifying 3902their behavior can be set in the "flags" field. Undefined flag bits must 3903be set to 0. 3904 3905Possible operations are: 3906 * ``KVM_S390_MEMOP_LOGICAL_READ`` 3907 * ``KVM_S390_MEMOP_LOGICAL_WRITE`` 3908 * ``KVM_S390_MEMOP_ABSOLUTE_READ`` 3909 * ``KVM_S390_MEMOP_ABSOLUTE_WRITE`` 3910 * ``KVM_S390_MEMOP_SIDA_READ`` 3911 * ``KVM_S390_MEMOP_SIDA_WRITE`` 3912 * ``KVM_S390_MEMOP_ABSOLUTE_CMPXCHG`` 3913 3914Logical read/write: 3915^^^^^^^^^^^^^^^^^^^ 3916 3917Access logical memory, i.e. translate the given guest address to an absolute 3918address given the state of the VCPU and use the absolute address as target of 3919the access. "ar" designates the access register number to be used; the valid 3920range is 0..15. 3921Logical accesses are permitted for the VCPU ioctl only. 3922Logical accesses are permitted for non-protected guests only. 3923 3924Supported flags: 3925 * ``KVM_S390_MEMOP_F_CHECK_ONLY`` 3926 * ``KVM_S390_MEMOP_F_INJECT_EXCEPTION`` 3927 * ``KVM_S390_MEMOP_F_SKEY_PROTECTION`` 3928 3929The KVM_S390_MEMOP_F_CHECK_ONLY flag can be set to check whether the 3930corresponding memory access would cause an access exception; however, 3931no actual access to the data in memory at the destination is performed. 3932In this case, "buf" is unused and can be NULL. 3933 3934In case an access exception occurred during the access (or would occur 3935in case of KVM_S390_MEMOP_F_CHECK_ONLY), the ioctl returns a positive 3936error number indicating the type of exception. This exception is also 3937raised directly at the corresponding VCPU if the flag 3938KVM_S390_MEMOP_F_INJECT_EXCEPTION is set. 3939On protection exceptions, unless specified otherwise, the injected 3940translation-exception identifier (TEID) indicates suppression. 3941 3942If the KVM_S390_MEMOP_F_SKEY_PROTECTION flag is set, storage key 3943protection is also in effect and may cause exceptions if accesses are 3944prohibited given the access key designated by "key"; the valid range is 0..15. 3945KVM_S390_MEMOP_F_SKEY_PROTECTION is available if KVM_CAP_S390_MEM_OP_EXTENSION 3946is > 0. 3947Since the accessed memory may span multiple pages and those pages might have 3948different storage keys, it is possible that a protection exception occurs 3949after memory has been modified. In this case, if the exception is injected, 3950the TEID does not indicate suppression. 3951 3952Absolute read/write: 3953^^^^^^^^^^^^^^^^^^^^ 3954 3955Access absolute memory. This operation is intended to be used with the 3956KVM_S390_MEMOP_F_SKEY_PROTECTION flag, to allow accessing memory and performing 3957the checks required for storage key protection as one operation (as opposed to 3958user space getting the storage keys, performing the checks, and accessing 3959memory thereafter, which could lead to a delay between check and access). 3960Absolute accesses are permitted for the VM ioctl if KVM_CAP_S390_MEM_OP_EXTENSION 3961has the KVM_S390_MEMOP_EXTENSION_CAP_BASE bit set. 3962Currently absolute accesses are not permitted for VCPU ioctls. 3963Absolute accesses are permitted for non-protected guests only. 3964 3965Supported flags: 3966 * ``KVM_S390_MEMOP_F_CHECK_ONLY`` 3967 * ``KVM_S390_MEMOP_F_SKEY_PROTECTION`` 3968 3969The semantics of the flags common with logical accesses are as for logical 3970accesses. 3971 3972Absolute cmpxchg: 3973^^^^^^^^^^^^^^^^^ 3974 3975Perform cmpxchg on absolute guest memory. Intended for use with the 3976KVM_S390_MEMOP_F_SKEY_PROTECTION flag. 3977Instead of doing an unconditional write, the access occurs only if the target 3978location contains the value pointed to by "old_addr". 3979This is performed as an atomic cmpxchg with the length specified by the "size" 3980parameter. "size" must be a power of two up to and including 16. 3981If the exchange did not take place because the target value doesn't match the 3982old value, the value "old_addr" points to is replaced by the target value. 3983User space can tell if an exchange took place by checking if this replacement 3984occurred. The cmpxchg op is permitted for the VM ioctl if 3985KVM_CAP_S390_MEM_OP_EXTENSION has flag KVM_S390_MEMOP_EXTENSION_CAP_CMPXCHG set. 3986 3987Supported flags: 3988 * ``KVM_S390_MEMOP_F_SKEY_PROTECTION`` 3989 3990SIDA read/write: 3991^^^^^^^^^^^^^^^^ 3992 3993Access the secure instruction data area which contains memory operands necessary 3994for instruction emulation for protected guests. 3995SIDA accesses are available if the KVM_CAP_S390_PROTECTED capability is available. 3996SIDA accesses are permitted for the VCPU ioctl only. 3997SIDA accesses are permitted for protected guests only. 3998 3999No flags are supported. 4000 40014.90 KVM_S390_GET_SKEYS 4002----------------------- 4003 4004:Capability: KVM_CAP_S390_SKEYS 4005:Architectures: s390 4006:Type: vm ioctl 4007:Parameters: struct kvm_s390_skeys 4008:Returns: 0 on success, KVM_S390_GET_SKEYS_NONE if guest is not using storage 4009 keys, negative value on error 4010 4011This ioctl is used to get guest storage key values on the s390 4012architecture. The ioctl takes parameters via the kvm_s390_skeys struct:: 4013 4014 struct kvm_s390_skeys { 4015 __u64 start_gfn; 4016 __u64 count; 4017 __u64 skeydata_addr; 4018 __u32 flags; 4019 __u32 reserved[9]; 4020 }; 4021 4022The start_gfn field is the number of the first guest frame whose storage keys 4023you want to get. 4024 4025The count field is the number of consecutive frames (starting from start_gfn) 4026whose storage keys to get. The count field must be at least 1 and the maximum 4027allowed value is defined as KVM_S390_SKEYS_MAX. Values outside this range 4028will cause the ioctl to return -EINVAL. 4029 4030The skeydata_addr field is the address to a buffer large enough to hold count 4031bytes. This buffer will be filled with storage key data by the ioctl. 4032 40334.91 KVM_S390_SET_SKEYS 4034----------------------- 4035 4036:Capability: KVM_CAP_S390_SKEYS 4037:Architectures: s390 4038:Type: vm ioctl 4039:Parameters: struct kvm_s390_skeys 4040:Returns: 0 on success, negative value on error 4041 4042This ioctl is used to set guest storage key values on the s390 4043architecture. The ioctl takes parameters via the kvm_s390_skeys struct. 4044See section on KVM_S390_GET_SKEYS for struct definition. 4045 4046The start_gfn field is the number of the first guest frame whose storage keys 4047you want to set. 4048 4049The count field is the number of consecutive frames (starting from start_gfn) 4050whose storage keys to get. The count field must be at least 1 and the maximum 4051allowed value is defined as KVM_S390_SKEYS_MAX. Values outside this range 4052will cause the ioctl to return -EINVAL. 4053 4054The skeydata_addr field is the address to a buffer containing count bytes of 4055storage keys. Each byte in the buffer will be set as the storage key for a 4056single frame starting at start_gfn for count frames. 4057 4058Note: If any architecturally invalid key value is found in the given data then 4059the ioctl will return -EINVAL. 4060 40614.92 KVM_S390_IRQ 4062----------------- 4063 4064:Capability: KVM_CAP_S390_INJECT_IRQ 4065:Architectures: s390 4066:Type: vcpu ioctl 4067:Parameters: struct kvm_s390_irq (in) 4068:Returns: 0 on success, -1 on error 4069 4070Errors: 4071 4072 4073 ====== ================================================================= 4074 EINVAL interrupt type is invalid 4075 type is KVM_S390_SIGP_STOP and flag parameter is invalid value, 4076 type is KVM_S390_INT_EXTERNAL_CALL and code is bigger 4077 than the maximum of VCPUs 4078 EBUSY type is KVM_S390_SIGP_SET_PREFIX and vcpu is not stopped, 4079 type is KVM_S390_SIGP_STOP and a stop irq is already pending, 4080 type is KVM_S390_INT_EXTERNAL_CALL and an external call interrupt 4081 is already pending 4082 ====== ================================================================= 4083 4084Allows to inject an interrupt to the guest. 4085 4086Using struct kvm_s390_irq as a parameter allows 4087to inject additional payload which is not 4088possible via KVM_S390_INTERRUPT. 4089 4090Interrupt parameters are passed via kvm_s390_irq:: 4091 4092 struct kvm_s390_irq { 4093 __u64 type; 4094 union { 4095 struct kvm_s390_io_info io; 4096 struct kvm_s390_ext_info ext; 4097 struct kvm_s390_pgm_info pgm; 4098 struct kvm_s390_emerg_info emerg; 4099 struct kvm_s390_extcall_info extcall; 4100 struct kvm_s390_prefix_info prefix; 4101 struct kvm_s390_stop_info stop; 4102 struct kvm_s390_mchk_info mchk; 4103 char reserved[64]; 4104 } u; 4105 }; 4106 4107type can be one of the following: 4108 4109- KVM_S390_SIGP_STOP - sigp stop; parameter in .stop 4110- KVM_S390_PROGRAM_INT - program check; parameters in .pgm 4111- KVM_S390_SIGP_SET_PREFIX - sigp set prefix; parameters in .prefix 4112- KVM_S390_RESTART - restart; no parameters 4113- KVM_S390_INT_CLOCK_COMP - clock comparator interrupt; no parameters 4114- KVM_S390_INT_CPU_TIMER - CPU timer interrupt; no parameters 4115- KVM_S390_INT_EMERGENCY - sigp emergency; parameters in .emerg 4116- KVM_S390_INT_EXTERNAL_CALL - sigp external call; parameters in .extcall 4117- KVM_S390_MCHK - machine check interrupt; parameters in .mchk 4118 4119This is an asynchronous vcpu ioctl and can be invoked from any thread. 4120 41214.94 KVM_S390_GET_IRQ_STATE 4122--------------------------- 4123 4124:Capability: KVM_CAP_S390_IRQ_STATE 4125:Architectures: s390 4126:Type: vcpu ioctl 4127:Parameters: struct kvm_s390_irq_state (out) 4128:Returns: >= number of bytes copied into buffer, 4129 -EINVAL if buffer size is 0, 4130 -ENOBUFS if buffer size is too small to fit all pending interrupts, 4131 -EFAULT if the buffer address was invalid 4132 4133This ioctl allows userspace to retrieve the complete state of all currently 4134pending interrupts in a single buffer. Use cases include migration 4135and introspection. The parameter structure contains the address of a 4136userspace buffer and its length:: 4137 4138 struct kvm_s390_irq_state { 4139 __u64 buf; 4140 __u32 flags; /* will stay unused for compatibility reasons */ 4141 __u32 len; 4142 __u32 reserved[4]; /* will stay unused for compatibility reasons */ 4143 }; 4144 4145Userspace passes in the above struct and for each pending interrupt a 4146struct kvm_s390_irq is copied to the provided buffer. 4147 4148The structure contains a flags and a reserved field for future extensions. As 4149the kernel never checked for flags == 0 and QEMU never pre-zeroed flags and 4150reserved, these fields can not be used in the future without breaking 4151compatibility. 4152 4153If -ENOBUFS is returned the buffer provided was too small and userspace 4154may retry with a bigger buffer. 4155 41564.95 KVM_S390_SET_IRQ_STATE 4157--------------------------- 4158 4159:Capability: KVM_CAP_S390_IRQ_STATE 4160:Architectures: s390 4161:Type: vcpu ioctl 4162:Parameters: struct kvm_s390_irq_state (in) 4163:Returns: 0 on success, 4164 -EFAULT if the buffer address was invalid, 4165 -EINVAL for an invalid buffer length (see below), 4166 -EBUSY if there were already interrupts pending, 4167 errors occurring when actually injecting the 4168 interrupt. See KVM_S390_IRQ. 4169 4170This ioctl allows userspace to set the complete state of all cpu-local 4171interrupts currently pending for the vcpu. It is intended for restoring 4172interrupt state after a migration. The input parameter is a userspace buffer 4173containing a struct kvm_s390_irq_state:: 4174 4175 struct kvm_s390_irq_state { 4176 __u64 buf; 4177 __u32 flags; /* will stay unused for compatibility reasons */ 4178 __u32 len; 4179 __u32 reserved[4]; /* will stay unused for compatibility reasons */ 4180 }; 4181 4182The restrictions for flags and reserved apply as well. 4183(see KVM_S390_GET_IRQ_STATE) 4184 4185The userspace memory referenced by buf contains a struct kvm_s390_irq 4186for each interrupt to be injected into the guest. 4187If one of the interrupts could not be injected for some reason the 4188ioctl aborts. 4189 4190len must be a multiple of sizeof(struct kvm_s390_irq). It must be > 0 4191and it must not exceed (max_vcpus + 32) * sizeof(struct kvm_s390_irq), 4192which is the maximum number of possibly pending cpu-local interrupts. 4193 41944.96 KVM_SMI 4195------------ 4196 4197:Capability: KVM_CAP_X86_SMM 4198:Architectures: x86 4199:Type: vcpu ioctl 4200:Parameters: none 4201:Returns: 0 on success, -1 on error 4202 4203Queues an SMI on the thread's vcpu. 4204 42054.97 KVM_X86_SET_MSR_FILTER 4206---------------------------- 4207 4208:Capability: KVM_CAP_X86_MSR_FILTER 4209:Architectures: x86 4210:Type: vm ioctl 4211:Parameters: struct kvm_msr_filter 4212:Returns: 0 on success, < 0 on error 4213 4214:: 4215 4216 struct kvm_msr_filter_range { 4217 #define KVM_MSR_FILTER_READ (1 << 0) 4218 #define KVM_MSR_FILTER_WRITE (1 << 1) 4219 __u32 flags; 4220 __u32 nmsrs; /* number of msrs in bitmap */ 4221 __u32 base; /* MSR index the bitmap starts at */ 4222 __u8 *bitmap; /* a 1 bit allows the operations in flags, 0 denies */ 4223 }; 4224 4225 #define KVM_MSR_FILTER_MAX_RANGES 16 4226 struct kvm_msr_filter { 4227 #define KVM_MSR_FILTER_DEFAULT_ALLOW (0 << 0) 4228 #define KVM_MSR_FILTER_DEFAULT_DENY (1 << 0) 4229 __u32 flags; 4230 struct kvm_msr_filter_range ranges[KVM_MSR_FILTER_MAX_RANGES]; 4231 }; 4232 4233flags values for ``struct kvm_msr_filter_range``: 4234 4235``KVM_MSR_FILTER_READ`` 4236 4237 Filter read accesses to MSRs using the given bitmap. A 0 in the bitmap 4238 indicates that read accesses should be denied, while a 1 indicates that 4239 a read for a particular MSR should be allowed regardless of the default 4240 filter action. 4241 4242``KVM_MSR_FILTER_WRITE`` 4243 4244 Filter write accesses to MSRs using the given bitmap. A 0 in the bitmap 4245 indicates that write accesses should be denied, while a 1 indicates that 4246 a write for a particular MSR should be allowed regardless of the default 4247 filter action. 4248 4249flags values for ``struct kvm_msr_filter``: 4250 4251``KVM_MSR_FILTER_DEFAULT_ALLOW`` 4252 4253 If no filter range matches an MSR index that is getting accessed, KVM will 4254 allow accesses to all MSRs by default. 4255 4256``KVM_MSR_FILTER_DEFAULT_DENY`` 4257 4258 If no filter range matches an MSR index that is getting accessed, KVM will 4259 deny accesses to all MSRs by default. 4260 4261This ioctl allows userspace to define up to 16 bitmaps of MSR ranges to deny 4262guest MSR accesses that would normally be allowed by KVM. If an MSR is not 4263covered by a specific range, the "default" filtering behavior applies. Each 4264bitmap range covers MSRs from [base .. base+nmsrs). 4265 4266If an MSR access is denied by userspace, the resulting KVM behavior depends on 4267whether or not KVM_CAP_X86_USER_SPACE_MSR's KVM_MSR_EXIT_REASON_FILTER is 4268enabled. If KVM_MSR_EXIT_REASON_FILTER is enabled, KVM will exit to userspace 4269on denied accesses, i.e. userspace effectively intercepts the MSR access. If 4270KVM_MSR_EXIT_REASON_FILTER is not enabled, KVM will inject a #GP into the guest 4271on denied accesses. Note, if an MSR access is denied during emulation of MSR 4272load/stores during VMX transitions, KVM ignores KVM_MSR_EXIT_REASON_FILTER. 4273See the below warning for full details. 4274 4275If an MSR access is allowed by userspace, KVM will emulate and/or virtualize 4276the access in accordance with the vCPU model. Note, KVM may still ultimately 4277inject a #GP if an access is allowed by userspace, e.g. if KVM doesn't support 4278the MSR, or to follow architectural behavior for the MSR. 4279 4280By default, KVM operates in KVM_MSR_FILTER_DEFAULT_ALLOW mode with no MSR range 4281filters. 4282 4283Calling this ioctl with an empty set of ranges (all nmsrs == 0) disables MSR 4284filtering. In that mode, ``KVM_MSR_FILTER_DEFAULT_DENY`` is invalid and causes 4285an error. 4286 4287.. warning:: 4288 MSR accesses that are side effects of instruction execution (emulated or 4289 native) are not filtered as hardware does not honor MSR bitmaps outside of 4290 RDMSR and WRMSR, and KVM mimics that behavior when emulating instructions 4291 to avoid pointless divergence from hardware. E.g. RDPID reads MSR_TSC_AUX, 4292 SYSENTER reads the SYSENTER MSRs, etc. 4293 4294 MSRs that are loaded/stored via dedicated VMCS fields are not filtered as 4295 part of VM-Enter/VM-Exit emulation. 4296 4297 MSRs that are loaded/store via VMX's load/store lists _are_ filtered as part 4298 of VM-Enter/VM-Exit emulation. If an MSR access is denied on VM-Enter, KVM 4299 synthesizes a consistency check VM-Exit(EXIT_REASON_MSR_LOAD_FAIL). If an 4300 MSR access is denied on VM-Exit, KVM synthesizes a VM-Abort. In short, KVM 4301 extends Intel's architectural list of MSRs that cannot be loaded/saved via 4302 the VM-Enter/VM-Exit MSR list. It is platform owner's responsibility to 4303 to communicate any such restrictions to their end users. 4304 4305 x2APIC MSR accesses cannot be filtered (KVM silently ignores filters that 4306 cover any x2APIC MSRs). 4307 4308Note, invoking this ioctl while a vCPU is running is inherently racy. However, 4309KVM does guarantee that vCPUs will see either the previous filter or the new 4310filter, e.g. MSRs with identical settings in both the old and new filter will 4311have deterministic behavior. 4312 4313Similarly, if userspace wishes to intercept on denied accesses, 4314KVM_MSR_EXIT_REASON_FILTER must be enabled before activating any filters, and 4315left enabled until after all filters are deactivated. Failure to do so may 4316result in KVM injecting a #GP instead of exiting to userspace. 4317 43184.98 KVM_CREATE_SPAPR_TCE_64 4319---------------------------- 4320 4321:Capability: KVM_CAP_SPAPR_TCE_64 4322:Architectures: powerpc 4323:Type: vm ioctl 4324:Parameters: struct kvm_create_spapr_tce_64 (in) 4325:Returns: file descriptor for manipulating the created TCE table 4326 4327This is an extension for KVM_CAP_SPAPR_TCE which only supports 32bit 4328windows, described in 4.62 KVM_CREATE_SPAPR_TCE 4329 4330This capability uses extended struct in ioctl interface:: 4331 4332 /* for KVM_CAP_SPAPR_TCE_64 */ 4333 struct kvm_create_spapr_tce_64 { 4334 __u64 liobn; 4335 __u32 page_shift; 4336 __u32 flags; 4337 __u64 offset; /* in pages */ 4338 __u64 size; /* in pages */ 4339 }; 4340 4341The aim of extension is to support an additional bigger DMA window with 4342a variable page size. 4343KVM_CREATE_SPAPR_TCE_64 receives a 64bit window size, an IOMMU page shift and 4344a bus offset of the corresponding DMA window, @size and @offset are numbers 4345of IOMMU pages. 4346 4347@flags are not used at the moment. 4348 4349The rest of functionality is identical to KVM_CREATE_SPAPR_TCE. 4350 43514.99 KVM_REINJECT_CONTROL 4352------------------------- 4353 4354:Capability: KVM_CAP_REINJECT_CONTROL 4355:Architectures: x86 4356:Type: vm ioctl 4357:Parameters: struct kvm_reinject_control (in) 4358:Returns: 0 on success, 4359 -EFAULT if struct kvm_reinject_control cannot be read, 4360 -ENXIO if KVM_CREATE_PIT or KVM_CREATE_PIT2 didn't succeed earlier. 4361 4362i8254 (PIT) has two modes, reinject and !reinject. The default is reinject, 4363where KVM queues elapsed i8254 ticks and monitors completion of interrupt from 4364vector(s) that i8254 injects. Reinject mode dequeues a tick and injects its 4365interrupt whenever there isn't a pending interrupt from i8254. 4366!reinject mode injects an interrupt as soon as a tick arrives. 4367 4368:: 4369 4370 struct kvm_reinject_control { 4371 __u8 pit_reinject; 4372 __u8 reserved[31]; 4373 }; 4374 4375pit_reinject = 0 (!reinject mode) is recommended, unless running an old 4376operating system that uses the PIT for timing (e.g. Linux 2.4.x). 4377 43784.100 KVM_PPC_CONFIGURE_V3_MMU 4379------------------------------ 4380 4381:Capability: KVM_CAP_PPC_MMU_RADIX or KVM_CAP_PPC_MMU_HASH_V3 4382:Architectures: ppc 4383:Type: vm ioctl 4384:Parameters: struct kvm_ppc_mmuv3_cfg (in) 4385:Returns: 0 on success, 4386 -EFAULT if struct kvm_ppc_mmuv3_cfg cannot be read, 4387 -EINVAL if the configuration is invalid 4388 4389This ioctl controls whether the guest will use radix or HPT (hashed 4390page table) translation, and sets the pointer to the process table for 4391the guest. 4392 4393:: 4394 4395 struct kvm_ppc_mmuv3_cfg { 4396 __u64 flags; 4397 __u64 process_table; 4398 }; 4399 4400There are two bits that can be set in flags; KVM_PPC_MMUV3_RADIX and 4401KVM_PPC_MMUV3_GTSE. KVM_PPC_MMUV3_RADIX, if set, configures the guest 4402to use radix tree translation, and if clear, to use HPT translation. 4403KVM_PPC_MMUV3_GTSE, if set and if KVM permits it, configures the guest 4404to be able to use the global TLB and SLB invalidation instructions; 4405if clear, the guest may not use these instructions. 4406 4407The process_table field specifies the address and size of the guest 4408process table, which is in the guest's space. This field is formatted 4409as the second doubleword of the partition table entry, as defined in 4410the Power ISA V3.00, Book III section 5.7.6.1. 4411 44124.101 KVM_PPC_GET_RMMU_INFO 4413--------------------------- 4414 4415:Capability: KVM_CAP_PPC_MMU_RADIX 4416:Architectures: ppc 4417:Type: vm ioctl 4418:Parameters: struct kvm_ppc_rmmu_info (out) 4419:Returns: 0 on success, 4420 -EFAULT if struct kvm_ppc_rmmu_info cannot be written, 4421 -EINVAL if no useful information can be returned 4422 4423This ioctl returns a structure containing two things: (a) a list 4424containing supported radix tree geometries, and (b) a list that maps 4425page sizes to put in the "AP" (actual page size) field for the tlbie 4426(TLB invalidate entry) instruction. 4427 4428:: 4429 4430 struct kvm_ppc_rmmu_info { 4431 struct kvm_ppc_radix_geom { 4432 __u8 page_shift; 4433 __u8 level_bits[4]; 4434 __u8 pad[3]; 4435 } geometries[8]; 4436 __u32 ap_encodings[8]; 4437 }; 4438 4439The geometries[] field gives up to 8 supported geometries for the 4440radix page table, in terms of the log base 2 of the smallest page 4441size, and the number of bits indexed at each level of the tree, from 4442the PTE level up to the PGD level in that order. Any unused entries 4443will have 0 in the page_shift field. 4444 4445The ap_encodings gives the supported page sizes and their AP field 4446encodings, encoded with the AP value in the top 3 bits and the log 4447base 2 of the page size in the bottom 6 bits. 4448 44494.102 KVM_PPC_RESIZE_HPT_PREPARE 4450-------------------------------- 4451 4452:Capability: KVM_CAP_SPAPR_RESIZE_HPT 4453:Architectures: powerpc 4454:Type: vm ioctl 4455:Parameters: struct kvm_ppc_resize_hpt (in) 4456:Returns: 0 on successful completion, 4457 >0 if a new HPT is being prepared, the value is an estimated 4458 number of milliseconds until preparation is complete, 4459 -EFAULT if struct kvm_reinject_control cannot be read, 4460 -EINVAL if the supplied shift or flags are invalid, 4461 -ENOMEM if unable to allocate the new HPT, 4462 4463Used to implement the PAPR extension for runtime resizing of a guest's 4464Hashed Page Table (HPT). Specifically this starts, stops or monitors 4465the preparation of a new potential HPT for the guest, essentially 4466implementing the H_RESIZE_HPT_PREPARE hypercall. 4467 4468:: 4469 4470 struct kvm_ppc_resize_hpt { 4471 __u64 flags; 4472 __u32 shift; 4473 __u32 pad; 4474 }; 4475 4476If called with shift > 0 when there is no pending HPT for the guest, 4477this begins preparation of a new pending HPT of size 2^(shift) bytes. 4478It then returns a positive integer with the estimated number of 4479milliseconds until preparation is complete. 4480 4481If called when there is a pending HPT whose size does not match that 4482requested in the parameters, discards the existing pending HPT and 4483creates a new one as above. 4484 4485If called when there is a pending HPT of the size requested, will: 4486 4487 * If preparation of the pending HPT is already complete, return 0 4488 * If preparation of the pending HPT has failed, return an error 4489 code, then discard the pending HPT. 4490 * If preparation of the pending HPT is still in progress, return an 4491 estimated number of milliseconds until preparation is complete. 4492 4493If called with shift == 0, discards any currently pending HPT and 4494returns 0 (i.e. cancels any in-progress preparation). 4495 4496flags is reserved for future expansion, currently setting any bits in 4497flags will result in an -EINVAL. 4498 4499Normally this will be called repeatedly with the same parameters until 4500it returns <= 0. The first call will initiate preparation, subsequent 4501ones will monitor preparation until it completes or fails. 4502 45034.103 KVM_PPC_RESIZE_HPT_COMMIT 4504------------------------------- 4505 4506:Capability: KVM_CAP_SPAPR_RESIZE_HPT 4507:Architectures: powerpc 4508:Type: vm ioctl 4509:Parameters: struct kvm_ppc_resize_hpt (in) 4510:Returns: 0 on successful completion, 4511 -EFAULT if struct kvm_reinject_control cannot be read, 4512 -EINVAL if the supplied shift or flags are invalid, 4513 -ENXIO is there is no pending HPT, or the pending HPT doesn't 4514 have the requested size, 4515 -EBUSY if the pending HPT is not fully prepared, 4516 -ENOSPC if there was a hash collision when moving existing 4517 HPT entries to the new HPT, 4518 -EIO on other error conditions 4519 4520Used to implement the PAPR extension for runtime resizing of a guest's 4521Hashed Page Table (HPT). Specifically this requests that the guest be 4522transferred to working with the new HPT, essentially implementing the 4523H_RESIZE_HPT_COMMIT hypercall. 4524 4525:: 4526 4527 struct kvm_ppc_resize_hpt { 4528 __u64 flags; 4529 __u32 shift; 4530 __u32 pad; 4531 }; 4532 4533This should only be called after KVM_PPC_RESIZE_HPT_PREPARE has 4534returned 0 with the same parameters. In other cases 4535KVM_PPC_RESIZE_HPT_COMMIT will return an error (usually -ENXIO or 4536-EBUSY, though others may be possible if the preparation was started, 4537but failed). 4538 4539This will have undefined effects on the guest if it has not already 4540placed itself in a quiescent state where no vcpu will make MMU enabled 4541memory accesses. 4542 4543On successful completion, the pending HPT will become the guest's active 4544HPT and the previous HPT will be discarded. 4545 4546On failure, the guest will still be operating on its previous HPT. 4547 45484.104 KVM_X86_GET_MCE_CAP_SUPPORTED 4549----------------------------------- 4550 4551:Capability: KVM_CAP_MCE 4552:Architectures: x86 4553:Type: system ioctl 4554:Parameters: u64 mce_cap (out) 4555:Returns: 0 on success, -1 on error 4556 4557Returns supported MCE capabilities. The u64 mce_cap parameter 4558has the same format as the MSR_IA32_MCG_CAP register. Supported 4559capabilities will have the corresponding bits set. 4560 45614.105 KVM_X86_SETUP_MCE 4562----------------------- 4563 4564:Capability: KVM_CAP_MCE 4565:Architectures: x86 4566:Type: vcpu ioctl 4567:Parameters: u64 mcg_cap (in) 4568:Returns: 0 on success, 4569 -EFAULT if u64 mcg_cap cannot be read, 4570 -EINVAL if the requested number of banks is invalid, 4571 -EINVAL if requested MCE capability is not supported. 4572 4573Initializes MCE support for use. The u64 mcg_cap parameter 4574has the same format as the MSR_IA32_MCG_CAP register and 4575specifies which capabilities should be enabled. The maximum 4576supported number of error-reporting banks can be retrieved when 4577checking for KVM_CAP_MCE. The supported capabilities can be 4578retrieved with KVM_X86_GET_MCE_CAP_SUPPORTED. 4579 45804.106 KVM_X86_SET_MCE 4581--------------------- 4582 4583:Capability: KVM_CAP_MCE 4584:Architectures: x86 4585:Type: vcpu ioctl 4586:Parameters: struct kvm_x86_mce (in) 4587:Returns: 0 on success, 4588 -EFAULT if struct kvm_x86_mce cannot be read, 4589 -EINVAL if the bank number is invalid, 4590 -EINVAL if VAL bit is not set in status field. 4591 4592Inject a machine check error (MCE) into the guest. The input 4593parameter is:: 4594 4595 struct kvm_x86_mce { 4596 __u64 status; 4597 __u64 addr; 4598 __u64 misc; 4599 __u64 mcg_status; 4600 __u8 bank; 4601 __u8 pad1[7]; 4602 __u64 pad2[3]; 4603 }; 4604 4605If the MCE being reported is an uncorrected error, KVM will 4606inject it as an MCE exception into the guest. If the guest 4607MCG_STATUS register reports that an MCE is in progress, KVM 4608causes an KVM_EXIT_SHUTDOWN vmexit. 4609 4610Otherwise, if the MCE is a corrected error, KVM will just 4611store it in the corresponding bank (provided this bank is 4612not holding a previously reported uncorrected error). 4613 46144.107 KVM_S390_GET_CMMA_BITS 4615---------------------------- 4616 4617:Capability: KVM_CAP_S390_CMMA_MIGRATION 4618:Architectures: s390 4619:Type: vm ioctl 4620:Parameters: struct kvm_s390_cmma_log (in, out) 4621:Returns: 0 on success, a negative value on error 4622 4623Errors: 4624 4625 ====== ============================================================= 4626 ENOMEM not enough memory can be allocated to complete the task 4627 ENXIO if CMMA is not enabled 4628 EINVAL if KVM_S390_CMMA_PEEK is not set but migration mode was not enabled 4629 EINVAL if KVM_S390_CMMA_PEEK is not set but dirty tracking has been 4630 disabled (and thus migration mode was automatically disabled) 4631 EFAULT if the userspace address is invalid or if no page table is 4632 present for the addresses (e.g. when using hugepages). 4633 ====== ============================================================= 4634 4635This ioctl is used to get the values of the CMMA bits on the s390 4636architecture. It is meant to be used in two scenarios: 4637 4638- During live migration to save the CMMA values. Live migration needs 4639 to be enabled via the KVM_REQ_START_MIGRATION VM property. 4640- To non-destructively peek at the CMMA values, with the flag 4641 KVM_S390_CMMA_PEEK set. 4642 4643The ioctl takes parameters via the kvm_s390_cmma_log struct. The desired 4644values are written to a buffer whose location is indicated via the "values" 4645member in the kvm_s390_cmma_log struct. The values in the input struct are 4646also updated as needed. 4647 4648Each CMMA value takes up one byte. 4649 4650:: 4651 4652 struct kvm_s390_cmma_log { 4653 __u64 start_gfn; 4654 __u32 count; 4655 __u32 flags; 4656 union { 4657 __u64 remaining; 4658 __u64 mask; 4659 }; 4660 __u64 values; 4661 }; 4662 4663start_gfn is the number of the first guest frame whose CMMA values are 4664to be retrieved, 4665 4666count is the length of the buffer in bytes, 4667 4668values points to the buffer where the result will be written to. 4669 4670If count is greater than KVM_S390_SKEYS_MAX, then it is considered to be 4671KVM_S390_SKEYS_MAX. KVM_S390_SKEYS_MAX is re-used for consistency with 4672other ioctls. 4673 4674The result is written in the buffer pointed to by the field values, and 4675the values of the input parameter are updated as follows. 4676 4677Depending on the flags, different actions are performed. The only 4678supported flag so far is KVM_S390_CMMA_PEEK. 4679 4680The default behaviour if KVM_S390_CMMA_PEEK is not set is: 4681start_gfn will indicate the first page frame whose CMMA bits were dirty. 4682It is not necessarily the same as the one passed as input, as clean pages 4683are skipped. 4684 4685count will indicate the number of bytes actually written in the buffer. 4686It can (and very often will) be smaller than the input value, since the 4687buffer is only filled until 16 bytes of clean values are found (which 4688are then not copied in the buffer). Since a CMMA migration block needs 4689the base address and the length, for a total of 16 bytes, we will send 4690back some clean data if there is some dirty data afterwards, as long as 4691the size of the clean data does not exceed the size of the header. This 4692allows to minimize the amount of data to be saved or transferred over 4693the network at the expense of more roundtrips to userspace. The next 4694invocation of the ioctl will skip over all the clean values, saving 4695potentially more than just the 16 bytes we found. 4696 4697If KVM_S390_CMMA_PEEK is set: 4698the existing storage attributes are read even when not in migration 4699mode, and no other action is performed; 4700 4701the output start_gfn will be equal to the input start_gfn, 4702 4703the output count will be equal to the input count, except if the end of 4704memory has been reached. 4705 4706In both cases: 4707the field "remaining" will indicate the total number of dirty CMMA values 4708still remaining, or 0 if KVM_S390_CMMA_PEEK is set and migration mode is 4709not enabled. 4710 4711mask is unused. 4712 4713values points to the userspace buffer where the result will be stored. 4714 47154.108 KVM_S390_SET_CMMA_BITS 4716---------------------------- 4717 4718:Capability: KVM_CAP_S390_CMMA_MIGRATION 4719:Architectures: s390 4720:Type: vm ioctl 4721:Parameters: struct kvm_s390_cmma_log (in) 4722:Returns: 0 on success, a negative value on error 4723 4724This ioctl is used to set the values of the CMMA bits on the s390 4725architecture. It is meant to be used during live migration to restore 4726the CMMA values, but there are no restrictions on its use. 4727The ioctl takes parameters via the kvm_s390_cmma_values struct. 4728Each CMMA value takes up one byte. 4729 4730:: 4731 4732 struct kvm_s390_cmma_log { 4733 __u64 start_gfn; 4734 __u32 count; 4735 __u32 flags; 4736 union { 4737 __u64 remaining; 4738 __u64 mask; 4739 }; 4740 __u64 values; 4741 }; 4742 4743start_gfn indicates the starting guest frame number, 4744 4745count indicates how many values are to be considered in the buffer, 4746 4747flags is not used and must be 0. 4748 4749mask indicates which PGSTE bits are to be considered. 4750 4751remaining is not used. 4752 4753values points to the buffer in userspace where to store the values. 4754 4755This ioctl can fail with -ENOMEM if not enough memory can be allocated to 4756complete the task, with -ENXIO if CMMA is not enabled, with -EINVAL if 4757the count field is too large (e.g. more than KVM_S390_CMMA_SIZE_MAX) or 4758if the flags field was not 0, with -EFAULT if the userspace address is 4759invalid, if invalid pages are written to (e.g. after the end of memory) 4760or if no page table is present for the addresses (e.g. when using 4761hugepages). 4762 47634.109 KVM_PPC_GET_CPU_CHAR 4764-------------------------- 4765 4766:Capability: KVM_CAP_PPC_GET_CPU_CHAR 4767:Architectures: powerpc 4768:Type: vm ioctl 4769:Parameters: struct kvm_ppc_cpu_char (out) 4770:Returns: 0 on successful completion, 4771 -EFAULT if struct kvm_ppc_cpu_char cannot be written 4772 4773This ioctl gives userspace information about certain characteristics 4774of the CPU relating to speculative execution of instructions and 4775possible information leakage resulting from speculative execution (see 4776CVE-2017-5715, CVE-2017-5753 and CVE-2017-5754). The information is 4777returned in struct kvm_ppc_cpu_char, which looks like this:: 4778 4779 struct kvm_ppc_cpu_char { 4780 __u64 character; /* characteristics of the CPU */ 4781 __u64 behaviour; /* recommended software behaviour */ 4782 __u64 character_mask; /* valid bits in character */ 4783 __u64 behaviour_mask; /* valid bits in behaviour */ 4784 }; 4785 4786For extensibility, the character_mask and behaviour_mask fields 4787indicate which bits of character and behaviour have been filled in by 4788the kernel. If the set of defined bits is extended in future then 4789userspace will be able to tell whether it is running on a kernel that 4790knows about the new bits. 4791 4792The character field describes attributes of the CPU which can help 4793with preventing inadvertent information disclosure - specifically, 4794whether there is an instruction to flash-invalidate the L1 data cache 4795(ori 30,30,0 or mtspr SPRN_TRIG2,rN), whether the L1 data cache is set 4796to a mode where entries can only be used by the thread that created 4797them, whether the bcctr[l] instruction prevents speculation, and 4798whether a speculation barrier instruction (ori 31,31,0) is provided. 4799 4800The behaviour field describes actions that software should take to 4801prevent inadvertent information disclosure, and thus describes which 4802vulnerabilities the hardware is subject to; specifically whether the 4803L1 data cache should be flushed when returning to user mode from the 4804kernel, and whether a speculation barrier should be placed between an 4805array bounds check and the array access. 4806 4807These fields use the same bit definitions as the new 4808H_GET_CPU_CHARACTERISTICS hypercall. 4809 48104.110 KVM_MEMORY_ENCRYPT_OP 4811--------------------------- 4812 4813:Capability: basic 4814:Architectures: x86 4815:Type: vm ioctl, vcpu ioctl 4816:Parameters: an opaque platform specific structure (in/out) 4817:Returns: 0 on success; -1 on error 4818 4819If the platform supports creating encrypted VMs then this ioctl can be used 4820for issuing platform-specific memory encryption commands to manage those 4821encrypted VMs. 4822 4823Currently, this ioctl is used for issuing both Secure Encrypted Virtualization 4824(SEV) commands on AMD Processors and Trusted Domain Extensions (TDX) commands 4825on Intel Processors. The detailed commands are defined in 4826Documentation/virt/kvm/x86/amd-memory-encryption.rst and 4827Documentation/virt/kvm/x86/intel-tdx.rst. 4828 48294.111 KVM_MEMORY_ENCRYPT_REG_REGION 4830----------------------------------- 4831 4832:Capability: basic 4833:Architectures: x86 4834:Type: system 4835:Parameters: struct kvm_enc_region (in) 4836:Returns: 0 on success; -1 on error 4837 4838This ioctl can be used to register a guest memory region which may 4839contain encrypted data (e.g. guest RAM, SMRAM etc). 4840 4841It is used in the SEV-enabled guest. When encryption is enabled, a guest 4842memory region may contain encrypted data. The SEV memory encryption 4843engine uses a tweak such that two identical plaintext pages, each at 4844different locations will have differing ciphertexts. So swapping or 4845moving ciphertext of those pages will not result in plaintext being 4846swapped. So relocating (or migrating) physical backing pages for the SEV 4847guest will require some additional steps. 4848 4849Note: The current SEV key management spec does not provide commands to 4850swap or migrate (move) ciphertext pages. Hence, for now we pin the guest 4851memory region registered with the ioctl. 4852 48534.112 KVM_MEMORY_ENCRYPT_UNREG_REGION 4854------------------------------------- 4855 4856:Capability: basic 4857:Architectures: x86 4858:Type: system 4859:Parameters: struct kvm_enc_region (in) 4860:Returns: 0 on success; -1 on error 4861 4862This ioctl can be used to unregister the guest memory region registered 4863with KVM_MEMORY_ENCRYPT_REG_REGION ioctl above. 4864 48654.113 KVM_HYPERV_EVENTFD 4866------------------------ 4867 4868:Capability: KVM_CAP_HYPERV_EVENTFD 4869:Architectures: x86 4870:Type: vm ioctl 4871:Parameters: struct kvm_hyperv_eventfd (in) 4872 4873This ioctl (un)registers an eventfd to receive notifications from the guest on 4874the specified Hyper-V connection id through the SIGNAL_EVENT hypercall, without 4875causing a user exit. SIGNAL_EVENT hypercall with non-zero event flag number 4876(bits 24-31) still triggers a KVM_EXIT_HYPERV_HCALL user exit. 4877 4878:: 4879 4880 struct kvm_hyperv_eventfd { 4881 __u32 conn_id; 4882 __s32 fd; 4883 __u32 flags; 4884 __u32 padding[3]; 4885 }; 4886 4887The conn_id field should fit within 24 bits:: 4888 4889 #define KVM_HYPERV_CONN_ID_MASK 0x00ffffff 4890 4891The acceptable values for the flags field are:: 4892 4893 #define KVM_HYPERV_EVENTFD_DEASSIGN (1 << 0) 4894 4895:Returns: 0 on success, 4896 -EINVAL if conn_id or flags is outside the allowed range, 4897 -ENOENT on deassign if the conn_id isn't registered, 4898 -EEXIST on assign if the conn_id is already registered 4899 49004.114 KVM_GET_NESTED_STATE 4901-------------------------- 4902 4903:Capability: KVM_CAP_NESTED_STATE 4904:Architectures: x86 4905:Type: vcpu ioctl 4906:Parameters: struct kvm_nested_state (in/out) 4907:Returns: 0 on success, -1 on error 4908 4909Errors: 4910 4911 ===== ============================================================= 4912 E2BIG the total state size exceeds the value of 'size' specified by 4913 the user; the size required will be written into size. 4914 ===== ============================================================= 4915 4916:: 4917 4918 struct kvm_nested_state { 4919 __u16 flags; 4920 __u16 format; 4921 __u32 size; 4922 4923 union { 4924 struct kvm_vmx_nested_state_hdr vmx; 4925 struct kvm_svm_nested_state_hdr svm; 4926 4927 /* Pad the header to 128 bytes. */ 4928 __u8 pad[120]; 4929 } hdr; 4930 4931 union { 4932 struct kvm_vmx_nested_state_data vmx[0]; 4933 struct kvm_svm_nested_state_data svm[0]; 4934 } data; 4935 }; 4936 4937 #define KVM_STATE_NESTED_GUEST_MODE 0x00000001 4938 #define KVM_STATE_NESTED_RUN_PENDING 0x00000002 4939 #define KVM_STATE_NESTED_EVMCS 0x00000004 4940 4941 #define KVM_STATE_NESTED_FORMAT_VMX 0 4942 #define KVM_STATE_NESTED_FORMAT_SVM 1 4943 4944 #define KVM_STATE_NESTED_VMX_VMCS_SIZE 0x1000 4945 4946 #define KVM_STATE_NESTED_VMX_SMM_GUEST_MODE 0x00000001 4947 #define KVM_STATE_NESTED_VMX_SMM_VMXON 0x00000002 4948 4949 #define KVM_STATE_VMX_PREEMPTION_TIMER_DEADLINE 0x00000001 4950 4951 struct kvm_vmx_nested_state_hdr { 4952 __u64 vmxon_pa; 4953 __u64 vmcs12_pa; 4954 4955 struct { 4956 __u16 flags; 4957 } smm; 4958 4959 __u32 flags; 4960 __u64 preemption_timer_deadline; 4961 }; 4962 4963 struct kvm_vmx_nested_state_data { 4964 __u8 vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE]; 4965 __u8 shadow_vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE]; 4966 }; 4967 4968This ioctl copies the vcpu's nested virtualization state from the kernel to 4969userspace. 4970 4971The maximum size of the state can be retrieved by passing KVM_CAP_NESTED_STATE 4972to the KVM_CHECK_EXTENSION ioctl(). 4973 49744.115 KVM_SET_NESTED_STATE 4975-------------------------- 4976 4977:Capability: KVM_CAP_NESTED_STATE 4978:Architectures: x86 4979:Type: vcpu ioctl 4980:Parameters: struct kvm_nested_state (in) 4981:Returns: 0 on success, -1 on error 4982 4983This copies the vcpu's kvm_nested_state struct from userspace to the kernel. 4984For the definition of struct kvm_nested_state, see KVM_GET_NESTED_STATE. 4985 49864.116 KVM_(UN)REGISTER_COALESCED_MMIO 4987------------------------------------- 4988 4989:Capability: KVM_CAP_COALESCED_MMIO (for coalesced mmio) 4990 KVM_CAP_COALESCED_PIO (for coalesced pio) 4991:Architectures: all 4992:Type: vm ioctl 4993:Parameters: struct kvm_coalesced_mmio_zone 4994:Returns: 0 on success, < 0 on error 4995 4996Coalesced I/O is a performance optimization that defers hardware 4997register write emulation so that userspace exits are avoided. It is 4998typically used to reduce the overhead of emulating frequently accessed 4999hardware registers. 5000 5001When a hardware register is configured for coalesced I/O, write accesses 5002do not exit to userspace and their value is recorded in a ring buffer 5003that is shared between kernel and userspace. 5004 5005Coalesced I/O is used if one or more write accesses to a hardware 5006register can be deferred until a read or a write to another hardware 5007register on the same device. This last access will cause a vmexit and 5008userspace will process accesses from the ring buffer before emulating 5009it. That will avoid exiting to userspace on repeated writes. 5010 5011Coalesced pio is based on coalesced mmio. There is little difference 5012between coalesced mmio and pio except that coalesced pio records accesses 5013to I/O ports. 5014 50154.117 KVM_CLEAR_DIRTY_LOG 5016------------------------- 5017 5018:Capability: KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 5019:Architectures: x86, arm64, mips 5020:Type: vm ioctl 5021:Parameters: struct kvm_clear_dirty_log (in) 5022:Returns: 0 on success, -1 on error 5023 5024:: 5025 5026 /* for KVM_CLEAR_DIRTY_LOG */ 5027 struct kvm_clear_dirty_log { 5028 __u32 slot; 5029 __u32 num_pages; 5030 __u64 first_page; 5031 union { 5032 void __user *dirty_bitmap; /* one bit per page */ 5033 __u64 padding; 5034 }; 5035 }; 5036 5037The ioctl clears the dirty status of pages in a memory slot, according to 5038the bitmap that is passed in struct kvm_clear_dirty_log's dirty_bitmap 5039field. Bit 0 of the bitmap corresponds to page "first_page" in the 5040memory slot, and num_pages is the size in bits of the input bitmap. 5041first_page must be a multiple of 64; num_pages must also be a multiple of 504264 unless first_page + num_pages is the size of the memory slot. For each 5043bit that is set in the input bitmap, the corresponding page is marked "clean" 5044in KVM's dirty bitmap, and dirty tracking is re-enabled for that page 5045(for example via write-protection, or by clearing the dirty bit in 5046a page table entry). 5047 5048If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 of slot field specifies 5049the address space for which you want to clear the dirty status. See 5050KVM_SET_USER_MEMORY_REGION for details on the usage of slot field. 5051 5052This ioctl is mostly useful when KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 5053is enabled; for more information, see the description of the capability. 5054However, it can always be used as long as KVM_CHECK_EXTENSION confirms 5055that KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is present. 5056 50574.118 KVM_GET_SUPPORTED_HV_CPUID 5058-------------------------------- 5059 5060:Capability: KVM_CAP_HYPERV_CPUID (vcpu), KVM_CAP_SYS_HYPERV_CPUID (system) 5061:Architectures: x86 5062:Type: system ioctl, vcpu ioctl 5063:Parameters: struct kvm_cpuid2 (in/out) 5064:Returns: 0 on success, -1 on error 5065 5066:: 5067 5068 struct kvm_cpuid2 { 5069 __u32 nent; 5070 __u32 padding; 5071 struct kvm_cpuid_entry2 entries[0]; 5072 }; 5073 5074 struct kvm_cpuid_entry2 { 5075 __u32 function; 5076 __u32 index; 5077 __u32 flags; 5078 __u32 eax; 5079 __u32 ebx; 5080 __u32 ecx; 5081 __u32 edx; 5082 __u32 padding[3]; 5083 }; 5084 5085This ioctl returns x86 cpuid features leaves related to Hyper-V emulation in 5086KVM. Userspace can use the information returned by this ioctl to construct 5087cpuid information presented to guests consuming Hyper-V enlightenments (e.g. 5088Windows or Hyper-V guests). 5089 5090CPUID feature leaves returned by this ioctl are defined by Hyper-V Top Level 5091Functional Specification (TLFS). These leaves can't be obtained with 5092KVM_GET_SUPPORTED_CPUID ioctl because some of them intersect with KVM feature 5093leaves (0x40000000, 0x40000001). 5094 5095Currently, the following list of CPUID leaves are returned: 5096 5097 - HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS 5098 - HYPERV_CPUID_INTERFACE 5099 - HYPERV_CPUID_VERSION 5100 - HYPERV_CPUID_FEATURES 5101 - HYPERV_CPUID_ENLIGHTMENT_INFO 5102 - HYPERV_CPUID_IMPLEMENT_LIMITS 5103 - HYPERV_CPUID_NESTED_FEATURES 5104 - HYPERV_CPUID_SYNDBG_VENDOR_AND_MAX_FUNCTIONS 5105 - HYPERV_CPUID_SYNDBG_INTERFACE 5106 - HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES 5107 5108Userspace invokes KVM_GET_SUPPORTED_HV_CPUID by passing a kvm_cpuid2 structure 5109with the 'nent' field indicating the number of entries in the variable-size 5110array 'entries'. If the number of entries is too low to describe all Hyper-V 5111feature leaves, an error (E2BIG) is returned. If the number is more or equal 5112to the number of Hyper-V feature leaves, the 'nent' field is adjusted to the 5113number of valid entries in the 'entries' array, which is then filled. 5114 5115'index' and 'flags' fields in 'struct kvm_cpuid_entry2' are currently reserved, 5116userspace should not expect to get any particular value there. 5117 5118Note, vcpu version of KVM_GET_SUPPORTED_HV_CPUID is currently deprecated. Unlike 5119system ioctl which exposes all supported feature bits unconditionally, vcpu 5120version has the following quirks: 5121 5122- HYPERV_CPUID_NESTED_FEATURES leaf and HV_X64_ENLIGHTENED_VMCS_RECOMMENDED 5123 feature bit are only exposed when Enlightened VMCS was previously enabled 5124 on the corresponding vCPU (KVM_CAP_HYPERV_ENLIGHTENED_VMCS). 5125- HV_STIMER_DIRECT_MODE_AVAILABLE bit is only exposed with in-kernel LAPIC. 5126 (presumes KVM_CREATE_IRQCHIP has already been called). 5127 51284.119 KVM_ARM_VCPU_FINALIZE 5129--------------------------- 5130 5131:Architectures: arm64 5132:Type: vcpu ioctl 5133:Parameters: int feature (in) 5134:Returns: 0 on success, -1 on error 5135 5136Errors: 5137 5138 ====== ============================================================== 5139 EPERM feature not enabled, needs configuration, or already finalized 5140 EINVAL feature unknown or not present 5141 ====== ============================================================== 5142 5143Recognised values for feature: 5144 5145 ===== =========================================== 5146 arm64 KVM_ARM_VCPU_SVE (requires KVM_CAP_ARM_SVE) 5147 ===== =========================================== 5148 5149Finalizes the configuration of the specified vcpu feature. 5150 5151The vcpu must already have been initialised, enabling the affected feature, by 5152means of a successful :ref:`KVM_ARM_VCPU_INIT <KVM_ARM_VCPU_INIT>` call with the 5153appropriate flag set in features[]. 5154 5155For affected vcpu features, this is a mandatory step that must be performed 5156before the vcpu is fully usable. 5157 5158Between KVM_ARM_VCPU_INIT and KVM_ARM_VCPU_FINALIZE, the feature may be 5159configured by use of ioctls such as KVM_SET_ONE_REG. The exact configuration 5160that should be performed and how to do it are feature-dependent. 5161 5162Other calls that depend on a particular feature being finalized, such as 5163KVM_RUN, KVM_GET_REG_LIST, KVM_GET_ONE_REG and KVM_SET_ONE_REG, will fail with 5164-EPERM unless the feature has already been finalized by means of a 5165KVM_ARM_VCPU_FINALIZE call. 5166 5167See KVM_ARM_VCPU_INIT for details of vcpu features that require finalization 5168using this ioctl. 5169 51704.120 KVM_SET_PMU_EVENT_FILTER 5171------------------------------ 5172 5173:Capability: KVM_CAP_PMU_EVENT_FILTER 5174:Architectures: x86 5175:Type: vm ioctl 5176:Parameters: struct kvm_pmu_event_filter (in) 5177:Returns: 0 on success, -1 on error 5178 5179Errors: 5180 5181 ====== ============================================================ 5182 EFAULT args[0] cannot be accessed 5183 EINVAL args[0] contains invalid data in the filter or filter events 5184 E2BIG nevents is too large 5185 EBUSY not enough memory to allocate the filter 5186 ====== ============================================================ 5187 5188:: 5189 5190 struct kvm_pmu_event_filter { 5191 __u32 action; 5192 __u32 nevents; 5193 __u32 fixed_counter_bitmap; 5194 __u32 flags; 5195 __u32 pad[4]; 5196 __u64 events[0]; 5197 }; 5198 5199This ioctl restricts the set of PMU events the guest can program by limiting 5200which event select and unit mask combinations are permitted. 5201 5202The argument holds a list of filter events which will be allowed or denied. 5203 5204Filter events only control general purpose counters; fixed purpose counters 5205are controlled by the fixed_counter_bitmap. 5206 5207Valid values for 'flags':: 5208 5209``0`` 5210 5211To use this mode, clear the 'flags' field. 5212 5213In this mode each event will contain an event select + unit mask. 5214 5215When the guest attempts to program the PMU the guest's event select + 5216unit mask is compared against the filter events to determine whether the 5217guest should have access. 5218 5219``KVM_PMU_EVENT_FLAG_MASKED_EVENTS`` 5220:Capability: KVM_CAP_PMU_EVENT_MASKED_EVENTS 5221 5222In this mode each filter event will contain an event select, mask, match, and 5223exclude value. To encode a masked event use:: 5224 5225 KVM_PMU_ENCODE_MASKED_ENTRY() 5226 5227An encoded event will follow this layout:: 5228 5229 Bits Description 5230 ---- ----------- 5231 7:0 event select (low bits) 5232 15:8 umask match 5233 31:16 unused 5234 35:32 event select (high bits) 5235 36:54 unused 5236 55 exclude bit 5237 63:56 umask mask 5238 5239When the guest attempts to program the PMU, these steps are followed in 5240determining if the guest should have access: 5241 5242 1. Match the event select from the guest against the filter events. 5243 2. If a match is found, match the guest's unit mask to the mask and match 5244 values of the included filter events. 5245 I.e. (unit mask & mask) == match && !exclude. 5246 3. If a match is found, match the guest's unit mask to the mask and match 5247 values of the excluded filter events. 5248 I.e. (unit mask & mask) == match && exclude. 5249 4. 5250 a. If an included match is found and an excluded match is not found, filter 5251 the event. 5252 b. For everything else, do not filter the event. 5253 5. 5254 a. If the event is filtered and it's an allow list, allow the guest to 5255 program the event. 5256 b. If the event is filtered and it's a deny list, do not allow the guest to 5257 program the event. 5258 5259When setting a new pmu event filter, -EINVAL will be returned if any of the 5260unused fields are set or if any of the high bits (35:32) in the event 5261select are set when called on Intel. 5262 5263Valid values for 'action':: 5264 5265 #define KVM_PMU_EVENT_ALLOW 0 5266 #define KVM_PMU_EVENT_DENY 1 5267 5268Via this API, KVM userspace can also control the behavior of the VM's fixed 5269counters (if any) by configuring the "action" and "fixed_counter_bitmap" fields. 5270 5271Specifically, KVM follows the following pseudo-code when determining whether to 5272allow the guest FixCtr[i] to count its pre-defined fixed event:: 5273 5274 FixCtr[i]_is_allowed = (action == ALLOW) && (bitmap & BIT(i)) || 5275 (action == DENY) && !(bitmap & BIT(i)); 5276 FixCtr[i]_is_denied = !FixCtr[i]_is_allowed; 5277 5278KVM always consumes fixed_counter_bitmap, it's userspace's responsibility to 5279ensure fixed_counter_bitmap is set correctly, e.g. if userspace wants to define 5280a filter that only affects general purpose counters. 5281 5282Note, the "events" field also applies to fixed counters' hardcoded event_select 5283and unit_mask values. "fixed_counter_bitmap" has higher priority than "events" 5284if there is a contradiction between the two. 5285 52864.121 KVM_PPC_SVM_OFF 5287--------------------- 5288 5289:Capability: basic 5290:Architectures: powerpc 5291:Type: vm ioctl 5292:Parameters: none 5293:Returns: 0 on successful completion, 5294 5295Errors: 5296 5297 ====== ================================================================ 5298 EINVAL if ultravisor failed to terminate the secure guest 5299 ENOMEM if hypervisor failed to allocate new radix page tables for guest 5300 ====== ================================================================ 5301 5302This ioctl is used to turn off the secure mode of the guest or transition 5303the guest from secure mode to normal mode. This is invoked when the guest 5304is reset. This has no effect if called for a normal guest. 5305 5306This ioctl issues an ultravisor call to terminate the secure guest, 5307unpins the VPA pages and releases all the device pages that are used to 5308track the secure pages by hypervisor. 5309 53104.122 KVM_S390_NORMAL_RESET 5311--------------------------- 5312 5313:Capability: KVM_CAP_S390_VCPU_RESETS 5314:Architectures: s390 5315:Type: vcpu ioctl 5316:Parameters: none 5317:Returns: 0 5318 5319This ioctl resets VCPU registers and control structures according to 5320the cpu reset definition in the POP (Principles Of Operation). 5321 53224.123 KVM_S390_INITIAL_RESET 5323---------------------------- 5324 5325:Capability: basic 5326:Architectures: s390 5327:Type: vcpu ioctl 5328:Parameters: none 5329:Returns: 0 5330 5331This ioctl resets VCPU registers and control structures according to 5332the initial cpu reset definition in the POP. However, the cpu is not 5333put into ESA mode. This reset is a superset of the normal reset. 5334 53354.124 KVM_S390_CLEAR_RESET 5336-------------------------- 5337 5338:Capability: KVM_CAP_S390_VCPU_RESETS 5339:Architectures: s390 5340:Type: vcpu ioctl 5341:Parameters: none 5342:Returns: 0 5343 5344This ioctl resets VCPU registers and control structures according to 5345the clear cpu reset definition in the POP. However, the cpu is not put 5346into ESA mode. This reset is a superset of the initial reset. 5347 5348 53494.125 KVM_S390_PV_COMMAND 5350------------------------- 5351 5352:Capability: KVM_CAP_S390_PROTECTED 5353:Architectures: s390 5354:Type: vm ioctl 5355:Parameters: struct kvm_pv_cmd 5356:Returns: 0 on success, < 0 on error 5357 5358:: 5359 5360 struct kvm_pv_cmd { 5361 __u32 cmd; /* Command to be executed */ 5362 __u16 rc; /* Ultravisor return code */ 5363 __u16 rrc; /* Ultravisor return reason code */ 5364 __u64 data; /* Data or address */ 5365 __u32 flags; /* flags for future extensions. Must be 0 for now */ 5366 __u32 reserved[3]; 5367 }; 5368 5369**Ultravisor return codes** 5370The Ultravisor return (reason) codes are provided by the kernel if a 5371Ultravisor call has been executed to achieve the results expected by 5372the command. Therefore they are independent of the IOCTL return 5373code. If KVM changes `rc`, its value will always be greater than 0 5374hence setting it to 0 before issuing a PV command is advised to be 5375able to detect a change of `rc`. 5376 5377**cmd values:** 5378 5379KVM_PV_ENABLE 5380 Allocate memory and register the VM with the Ultravisor, thereby 5381 donating memory to the Ultravisor that will become inaccessible to 5382 KVM. All existing CPUs are converted to protected ones. After this 5383 command has succeeded, any CPU added via hotplug will become 5384 protected during its creation as well. 5385 5386 Errors: 5387 5388 ===== ============================= 5389 EINTR an unmasked signal is pending 5390 ===== ============================= 5391 5392KVM_PV_DISABLE 5393 Deregister the VM from the Ultravisor and reclaim the memory that had 5394 been donated to the Ultravisor, making it usable by the kernel again. 5395 All registered VCPUs are converted back to non-protected ones. If a 5396 previous protected VM had been prepared for asynchronous teardown with 5397 KVM_PV_ASYNC_CLEANUP_PREPARE and not subsequently torn down with 5398 KVM_PV_ASYNC_CLEANUP_PERFORM, it will be torn down in this call 5399 together with the current protected VM. 5400 5401KVM_PV_VM_SET_SEC_PARMS 5402 Pass the image header from VM memory to the Ultravisor in 5403 preparation of image unpacking and verification. 5404 5405KVM_PV_VM_UNPACK 5406 Unpack (protect and decrypt) a page of the encrypted boot image. 5407 5408KVM_PV_VM_VERIFY 5409 Verify the integrity of the unpacked image. Only if this succeeds, 5410 KVM is allowed to start protected VCPUs. 5411 5412KVM_PV_INFO 5413 :Capability: KVM_CAP_S390_PROTECTED_DUMP 5414 5415 Presents an API that provides Ultravisor related data to userspace 5416 via subcommands. len_max is the size of the user space buffer, 5417 len_written is KVM's indication of how much bytes of that buffer 5418 were actually written to. len_written can be used to determine the 5419 valid fields if more response fields are added in the future. 5420 5421 :: 5422 5423 enum pv_cmd_info_id { 5424 KVM_PV_INFO_VM, 5425 KVM_PV_INFO_DUMP, 5426 }; 5427 5428 struct kvm_s390_pv_info_header { 5429 __u32 id; 5430 __u32 len_max; 5431 __u32 len_written; 5432 __u32 reserved; 5433 }; 5434 5435 struct kvm_s390_pv_info { 5436 struct kvm_s390_pv_info_header header; 5437 struct kvm_s390_pv_info_dump dump; 5438 struct kvm_s390_pv_info_vm vm; 5439 }; 5440 5441**subcommands:** 5442 5443 KVM_PV_INFO_VM 5444 This subcommand provides basic Ultravisor information for PV 5445 hosts. These values are likely also exported as files in the sysfs 5446 firmware UV query interface but they are more easily available to 5447 programs in this API. 5448 5449 The installed calls and feature_indication members provide the 5450 installed UV calls and the UV's other feature indications. 5451 5452 The max_* members provide information about the maximum number of PV 5453 vcpus, PV guests and PV guest memory size. 5454 5455 :: 5456 5457 struct kvm_s390_pv_info_vm { 5458 __u64 inst_calls_list[4]; 5459 __u64 max_cpus; 5460 __u64 max_guests; 5461 __u64 max_guest_addr; 5462 __u64 feature_indication; 5463 }; 5464 5465 5466 KVM_PV_INFO_DUMP 5467 This subcommand provides information related to dumping PV guests. 5468 5469 :: 5470 5471 struct kvm_s390_pv_info_dump { 5472 __u64 dump_cpu_buffer_len; 5473 __u64 dump_config_mem_buffer_per_1m; 5474 __u64 dump_config_finalize_len; 5475 }; 5476 5477KVM_PV_DUMP 5478 :Capability: KVM_CAP_S390_PROTECTED_DUMP 5479 5480 Presents an API that provides calls which facilitate dumping a 5481 protected VM. 5482 5483 :: 5484 5485 struct kvm_s390_pv_dmp { 5486 __u64 subcmd; 5487 __u64 buff_addr; 5488 __u64 buff_len; 5489 __u64 gaddr; /* For dump storage state */ 5490 }; 5491 5492 **subcommands:** 5493 5494 KVM_PV_DUMP_INIT 5495 Initializes the dump process of a protected VM. If this call does 5496 not succeed all other subcommands will fail with -EINVAL. This 5497 subcommand will return -EINVAL if a dump process has not yet been 5498 completed. 5499 5500 Not all PV vms can be dumped, the owner needs to set `dump 5501 allowed` PCF bit 34 in the SE header to allow dumping. 5502 5503 KVM_PV_DUMP_CONFIG_STOR_STATE 5504 Stores `buff_len` bytes of tweak component values starting with 5505 the 1MB block specified by the absolute guest address 5506 (`gaddr`). `buff_len` needs to be `conf_dump_storage_state_len` 5507 aligned and at least >= the `conf_dump_storage_state_len` value 5508 provided by the dump uv_info data. buff_user might be written to 5509 even if an error rc is returned. For instance if we encounter a 5510 fault after writing the first page of data. 5511 5512 KVM_PV_DUMP_COMPLETE 5513 If the subcommand succeeds it completes the dump process and lets 5514 KVM_PV_DUMP_INIT be called again. 5515 5516 On success `conf_dump_finalize_len` bytes of completion data will be 5517 stored to the `buff_addr`. The completion data contains a key 5518 derivation seed, IV, tweak nonce and encryption keys as well as an 5519 authentication tag all of which are needed to decrypt the dump at a 5520 later time. 5521 5522KVM_PV_ASYNC_CLEANUP_PREPARE 5523 :Capability: KVM_CAP_S390_PROTECTED_ASYNC_DISABLE 5524 5525 Prepare the current protected VM for asynchronous teardown. Most 5526 resources used by the current protected VM will be set aside for a 5527 subsequent asynchronous teardown. The current protected VM will then 5528 resume execution immediately as non-protected. There can be at most 5529 one protected VM prepared for asynchronous teardown at any time. If 5530 a protected VM had already been prepared for teardown without 5531 subsequently calling KVM_PV_ASYNC_CLEANUP_PERFORM, this call will 5532 fail. In that case, the userspace process should issue a normal 5533 KVM_PV_DISABLE. The resources set aside with this call will need to 5534 be cleaned up with a subsequent call to KVM_PV_ASYNC_CLEANUP_PERFORM 5535 or KVM_PV_DISABLE, otherwise they will be cleaned up when KVM 5536 terminates. KVM_PV_ASYNC_CLEANUP_PREPARE can be called again as soon 5537 as cleanup starts, i.e. before KVM_PV_ASYNC_CLEANUP_PERFORM finishes. 5538 5539KVM_PV_ASYNC_CLEANUP_PERFORM 5540 :Capability: KVM_CAP_S390_PROTECTED_ASYNC_DISABLE 5541 5542 Tear down the protected VM previously prepared for teardown with 5543 KVM_PV_ASYNC_CLEANUP_PREPARE. The resources that had been set aside 5544 will be freed during the execution of this command. This PV command 5545 should ideally be issued by userspace from a separate thread. If a 5546 fatal signal is received (or the process terminates naturally), the 5547 command will terminate immediately without completing, and the normal 5548 KVM shutdown procedure will take care of cleaning up all remaining 5549 protected VMs, including the ones whose teardown was interrupted by 5550 process termination. 5551 55524.126 KVM_XEN_HVM_SET_ATTR 5553-------------------------- 5554 5555:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5556:Architectures: x86 5557:Type: vm ioctl 5558:Parameters: struct kvm_xen_hvm_attr 5559:Returns: 0 on success, < 0 on error 5560 5561:: 5562 5563 struct kvm_xen_hvm_attr { 5564 __u16 type; 5565 __u16 pad[3]; 5566 union { 5567 __u8 long_mode; 5568 __u8 vector; 5569 __u8 runstate_update_flag; 5570 union { 5571 __u64 gfn; 5572 __u64 hva; 5573 } shared_info; 5574 struct { 5575 __u32 send_port; 5576 __u32 type; /* EVTCHNSTAT_ipi / EVTCHNSTAT_interdomain */ 5577 __u32 flags; 5578 union { 5579 struct { 5580 __u32 port; 5581 __u32 vcpu; 5582 __u32 priority; 5583 } port; 5584 struct { 5585 __u32 port; /* Zero for eventfd */ 5586 __s32 fd; 5587 } eventfd; 5588 __u32 padding[4]; 5589 } deliver; 5590 } evtchn; 5591 __u32 xen_version; 5592 __u64 pad[8]; 5593 } u; 5594 }; 5595 5596type values: 5597 5598KVM_XEN_ATTR_TYPE_LONG_MODE 5599 Sets the ABI mode of the VM to 32-bit or 64-bit (long mode). This 5600 determines the layout of the shared_info page exposed to the VM. 5601 5602KVM_XEN_ATTR_TYPE_SHARED_INFO 5603 Sets the guest physical frame number at which the Xen shared_info 5604 page resides. Note that although Xen places vcpu_info for the first 5605 32 vCPUs in the shared_info page, KVM does not automatically do so 5606 and instead requires that KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO or 5607 KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO_HVA be used explicitly even when 5608 the vcpu_info for a given vCPU resides at the "default" location 5609 in the shared_info page. This is because KVM may not be aware of 5610 the Xen CPU id which is used as the index into the vcpu_info[] 5611 array, so may know the correct default location. 5612 5613 Note that the shared_info page may be constantly written to by KVM; 5614 it contains the event channel bitmap used to deliver interrupts to 5615 a Xen guest, amongst other things. It is exempt from dirty tracking 5616 mechanisms — KVM will not explicitly mark the page as dirty each 5617 time an event channel interrupt is delivered to the guest! Thus, 5618 userspace should always assume that the designated GFN is dirty if 5619 any vCPU has been running or any event channel interrupts can be 5620 routed to the guest. 5621 5622 Setting the gfn to KVM_XEN_INVALID_GFN will disable the shared_info 5623 page. 5624 5625KVM_XEN_ATTR_TYPE_SHARED_INFO_HVA 5626 If the KVM_XEN_HVM_CONFIG_SHARED_INFO_HVA flag is also set in the 5627 Xen capabilities, then this attribute may be used to set the 5628 userspace address at which the shared_info page resides, which 5629 will always be fixed in the VMM regardless of where it is mapped 5630 in guest physical address space. This attribute should be used in 5631 preference to KVM_XEN_ATTR_TYPE_SHARED_INFO as it avoids 5632 unnecessary invalidation of an internal cache when the page is 5633 re-mapped in guest physical address space. 5634 5635 Setting the hva to zero will disable the shared_info page. 5636 5637KVM_XEN_ATTR_TYPE_UPCALL_VECTOR 5638 Sets the exception vector used to deliver Xen event channel upcalls. 5639 This is the HVM-wide vector injected directly by the hypervisor 5640 (not through the local APIC), typically configured by a guest via 5641 HVM_PARAM_CALLBACK_IRQ. This can be disabled again (e.g. for guest 5642 SHUTDOWN_soft_reset) by setting it to zero. 5643 5644KVM_XEN_ATTR_TYPE_EVTCHN 5645 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5646 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It configures 5647 an outbound port number for interception of EVTCHNOP_send requests 5648 from the guest. A given sending port number may be directed back to 5649 a specified vCPU (by APIC ID) / port / priority on the guest, or to 5650 trigger events on an eventfd. The vCPU and priority can be changed 5651 by setting KVM_XEN_EVTCHN_UPDATE in a subsequent call, but other 5652 fields cannot change for a given sending port. A port mapping is 5653 removed by using KVM_XEN_EVTCHN_DEASSIGN in the flags field. Passing 5654 KVM_XEN_EVTCHN_RESET in the flags field removes all interception of 5655 outbound event channels. The values of the flags field are mutually 5656 exclusive and cannot be combined as a bitmask. 5657 5658KVM_XEN_ATTR_TYPE_XEN_VERSION 5659 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5660 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It configures 5661 the 32-bit version code returned to the guest when it invokes the 5662 XENVER_version call; typically (XEN_MAJOR << 16 | XEN_MINOR). PV 5663 Xen guests will often use this to as a dummy hypercall to trigger 5664 event channel delivery, so responding within the kernel without 5665 exiting to userspace is beneficial. 5666 5667KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG 5668 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5669 support for KVM_XEN_HVM_CONFIG_RUNSTATE_UPDATE_FLAG. It enables the 5670 XEN_RUNSTATE_UPDATE flag which allows guest vCPUs to safely read 5671 other vCPUs' vcpu_runstate_info. Xen guests enable this feature via 5672 the VMASST_TYPE_runstate_update_flag of the HYPERVISOR_vm_assist 5673 hypercall. 5674 56754.127 KVM_XEN_HVM_GET_ATTR 5676-------------------------- 5677 5678:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5679:Architectures: x86 5680:Type: vm ioctl 5681:Parameters: struct kvm_xen_hvm_attr 5682:Returns: 0 on success, < 0 on error 5683 5684Allows Xen VM attributes to be read. For the structure and types, 5685see KVM_XEN_HVM_SET_ATTR above. The KVM_XEN_ATTR_TYPE_EVTCHN 5686attribute cannot be read. 5687 56884.128 KVM_XEN_VCPU_SET_ATTR 5689--------------------------- 5690 5691:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5692:Architectures: x86 5693:Type: vcpu ioctl 5694:Parameters: struct kvm_xen_vcpu_attr 5695:Returns: 0 on success, < 0 on error 5696 5697:: 5698 5699 struct kvm_xen_vcpu_attr { 5700 __u16 type; 5701 __u16 pad[3]; 5702 union { 5703 __u64 gpa; 5704 __u64 pad[4]; 5705 struct { 5706 __u64 state; 5707 __u64 state_entry_time; 5708 __u64 time_running; 5709 __u64 time_runnable; 5710 __u64 time_blocked; 5711 __u64 time_offline; 5712 } runstate; 5713 __u32 vcpu_id; 5714 struct { 5715 __u32 port; 5716 __u32 priority; 5717 __u64 expires_ns; 5718 } timer; 5719 __u8 vector; 5720 } u; 5721 }; 5722 5723type values: 5724 5725KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO 5726 Sets the guest physical address of the vcpu_info for a given vCPU. 5727 As with the shared_info page for the VM, the corresponding page may be 5728 dirtied at any time if event channel interrupt delivery is enabled, so 5729 userspace should always assume that the page is dirty without relying 5730 on dirty logging. Setting the gpa to KVM_XEN_INVALID_GPA will disable 5731 the vcpu_info. 5732 5733KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO_HVA 5734 If the KVM_XEN_HVM_CONFIG_SHARED_INFO_HVA flag is also set in the 5735 Xen capabilities, then this attribute may be used to set the 5736 userspace address of the vcpu_info for a given vCPU. It should 5737 only be used when the vcpu_info resides at the "default" location 5738 in the shared_info page. In this case it is safe to assume the 5739 userspace address will not change, because the shared_info page is 5740 an overlay on guest memory and remains at a fixed host address 5741 regardless of where it is mapped in guest physical address space 5742 and hence unnecessary invalidation of an internal cache may be 5743 avoided if the guest memory layout is modified. 5744 If the vcpu_info does not reside at the "default" location then 5745 it is not guaranteed to remain at the same host address and 5746 hence the aforementioned cache invalidation is required. 5747 5748KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO 5749 Sets the guest physical address of an additional pvclock structure 5750 for a given vCPU. This is typically used for guest vsyscall support. 5751 Setting the gpa to KVM_XEN_INVALID_GPA will disable the structure. 5752 5753KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR 5754 Sets the guest physical address of the vcpu_runstate_info for a given 5755 vCPU. This is how a Xen guest tracks CPU state such as steal time. 5756 Setting the gpa to KVM_XEN_INVALID_GPA will disable the runstate area. 5757 5758KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT 5759 Sets the runstate (RUNSTATE_running/_runnable/_blocked/_offline) of 5760 the given vCPU from the .u.runstate.state member of the structure. 5761 KVM automatically accounts running and runnable time but blocked 5762 and offline states are only entered explicitly. 5763 5764KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA 5765 Sets all fields of the vCPU runstate data from the .u.runstate member 5766 of the structure, including the current runstate. The state_entry_time 5767 must equal the sum of the other four times. 5768 5769KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST 5770 This *adds* the contents of the .u.runstate members of the structure 5771 to the corresponding members of the given vCPU's runstate data, thus 5772 permitting atomic adjustments to the runstate times. The adjustment 5773 to the state_entry_time must equal the sum of the adjustments to the 5774 other four times. The state field must be set to -1, or to a valid 5775 runstate value (RUNSTATE_running, RUNSTATE_runnable, RUNSTATE_blocked 5776 or RUNSTATE_offline) to set the current accounted state as of the 5777 adjusted state_entry_time. 5778 5779KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID 5780 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5781 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It sets the Xen 5782 vCPU ID of the given vCPU, to allow timer-related VCPU operations to 5783 be intercepted by KVM. 5784 5785KVM_XEN_VCPU_ATTR_TYPE_TIMER 5786 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5787 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It sets the 5788 event channel port/priority for the VIRQ_TIMER of the vCPU, as well 5789 as allowing a pending timer to be saved/restored. Setting the timer 5790 port to zero disables kernel handling of the singleshot timer. 5791 5792KVM_XEN_VCPU_ATTR_TYPE_UPCALL_VECTOR 5793 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5794 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It sets the 5795 per-vCPU local APIC upcall vector, configured by a Xen guest with 5796 the HVMOP_set_evtchn_upcall_vector hypercall. This is typically 5797 used by Windows guests, and is distinct from the HVM-wide upcall 5798 vector configured with HVM_PARAM_CALLBACK_IRQ. It is disabled by 5799 setting the vector to zero. 5800 5801 58024.129 KVM_XEN_VCPU_GET_ATTR 5803--------------------------- 5804 5805:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5806:Architectures: x86 5807:Type: vcpu ioctl 5808:Parameters: struct kvm_xen_vcpu_attr 5809:Returns: 0 on success, < 0 on error 5810 5811Allows Xen vCPU attributes to be read. For the structure and types, 5812see KVM_XEN_VCPU_SET_ATTR above. 5813 5814The KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST type may not be used 5815with the KVM_XEN_VCPU_GET_ATTR ioctl. 5816 58174.130 KVM_ARM_MTE_COPY_TAGS 5818--------------------------- 5819 5820:Capability: KVM_CAP_ARM_MTE 5821:Architectures: arm64 5822:Type: vm ioctl 5823:Parameters: struct kvm_arm_copy_mte_tags 5824:Returns: number of bytes copied, < 0 on error (-EINVAL for incorrect 5825 arguments, -EFAULT if memory cannot be accessed). 5826 5827:: 5828 5829 struct kvm_arm_copy_mte_tags { 5830 __u64 guest_ipa; 5831 __u64 length; 5832 void __user *addr; 5833 __u64 flags; 5834 __u64 reserved[2]; 5835 }; 5836 5837Copies Memory Tagging Extension (MTE) tags to/from guest tag memory. The 5838``guest_ipa`` and ``length`` fields must be ``PAGE_SIZE`` aligned. 5839``length`` must not be bigger than 2^31 - PAGE_SIZE bytes. The ``addr`` 5840field must point to a buffer which the tags will be copied to or from. 5841 5842``flags`` specifies the direction of copy, either ``KVM_ARM_TAGS_TO_GUEST`` or 5843``KVM_ARM_TAGS_FROM_GUEST``. 5844 5845The size of the buffer to store the tags is ``(length / 16)`` bytes 5846(granules in MTE are 16 bytes long). Each byte contains a single tag 5847value. This matches the format of ``PTRACE_PEEKMTETAGS`` and 5848``PTRACE_POKEMTETAGS``. 5849 5850If an error occurs before any data is copied then a negative error code is 5851returned. If some tags have been copied before an error occurs then the number 5852of bytes successfully copied is returned. If the call completes successfully 5853then ``length`` is returned. 5854 58554.131 KVM_GET_SREGS2 5856-------------------- 5857 5858:Capability: KVM_CAP_SREGS2 5859:Architectures: x86 5860:Type: vcpu ioctl 5861:Parameters: struct kvm_sregs2 (out) 5862:Returns: 0 on success, -1 on error 5863 5864Reads special registers from the vcpu. 5865This ioctl (when supported) replaces the KVM_GET_SREGS. 5866 5867:: 5868 5869 struct kvm_sregs2 { 5870 /* out (KVM_GET_SREGS2) / in (KVM_SET_SREGS2) */ 5871 struct kvm_segment cs, ds, es, fs, gs, ss; 5872 struct kvm_segment tr, ldt; 5873 struct kvm_dtable gdt, idt; 5874 __u64 cr0, cr2, cr3, cr4, cr8; 5875 __u64 efer; 5876 __u64 apic_base; 5877 __u64 flags; 5878 __u64 pdptrs[4]; 5879 }; 5880 5881flags values for ``kvm_sregs2``: 5882 5883``KVM_SREGS2_FLAGS_PDPTRS_VALID`` 5884 5885 Indicates that the struct contains valid PDPTR values. 5886 5887 58884.132 KVM_SET_SREGS2 5889-------------------- 5890 5891:Capability: KVM_CAP_SREGS2 5892:Architectures: x86 5893:Type: vcpu ioctl 5894:Parameters: struct kvm_sregs2 (in) 5895:Returns: 0 on success, -1 on error 5896 5897Writes special registers into the vcpu. 5898See KVM_GET_SREGS2 for the data structures. 5899This ioctl (when supported) replaces the KVM_SET_SREGS. 5900 59014.133 KVM_GET_STATS_FD 5902---------------------- 5903 5904:Capability: KVM_CAP_STATS_BINARY_FD 5905:Architectures: all 5906:Type: vm ioctl, vcpu ioctl 5907:Parameters: none 5908:Returns: statistics file descriptor on success, < 0 on error 5909 5910Errors: 5911 5912 ====== ====================================================== 5913 ENOMEM if the fd could not be created due to lack of memory 5914 EMFILE if the number of opened files exceeds the limit 5915 ====== ====================================================== 5916 5917The returned file descriptor can be used to read VM/vCPU statistics data in 5918binary format. The data in the file descriptor consists of four blocks 5919organized as follows: 5920 5921+-------------+ 5922| Header | 5923+-------------+ 5924| id string | 5925+-------------+ 5926| Descriptors | 5927+-------------+ 5928| Stats Data | 5929+-------------+ 5930 5931Apart from the header starting at offset 0, please be aware that it is 5932not guaranteed that the four blocks are adjacent or in the above order; 5933the offsets of the id, descriptors and data blocks are found in the 5934header. However, all four blocks are aligned to 64 bit offsets in the 5935file and they do not overlap. 5936 5937All blocks except the data block are immutable. Userspace can read them 5938only one time after retrieving the file descriptor, and then use ``pread`` or 5939``lseek`` to read the statistics repeatedly. 5940 5941All data is in system endianness. 5942 5943The format of the header is as follows:: 5944 5945 struct kvm_stats_header { 5946 __u32 flags; 5947 __u32 name_size; 5948 __u32 num_desc; 5949 __u32 id_offset; 5950 __u32 desc_offset; 5951 __u32 data_offset; 5952 }; 5953 5954The ``flags`` field is not used at the moment. It is always read as 0. 5955 5956The ``name_size`` field is the size (in byte) of the statistics name string 5957(including trailing '\0') which is contained in the "id string" block and 5958appended at the end of every descriptor. 5959 5960The ``num_desc`` field is the number of descriptors that are included in the 5961descriptor block. (The actual number of values in the data block may be 5962larger, since each descriptor may comprise more than one value). 5963 5964The ``id_offset`` field is the offset of the id string from the start of the 5965file indicated by the file descriptor. It is a multiple of 8. 5966 5967The ``desc_offset`` field is the offset of the Descriptors block from the start 5968of the file indicated by the file descriptor. It is a multiple of 8. 5969 5970The ``data_offset`` field is the offset of the Stats Data block from the start 5971of the file indicated by the file descriptor. It is a multiple of 8. 5972 5973The id string block contains a string which identifies the file descriptor on 5974which KVM_GET_STATS_FD was invoked. The size of the block, including the 5975trailing ``'\0'``, is indicated by the ``name_size`` field in the header. 5976 5977The descriptors block is only needed to be read once for the lifetime of the 5978file descriptor contains a sequence of ``struct kvm_stats_desc``, each followed 5979by a string of size ``name_size``. 5980:: 5981 5982 #define KVM_STATS_TYPE_SHIFT 0 5983 #define KVM_STATS_TYPE_MASK (0xF << KVM_STATS_TYPE_SHIFT) 5984 #define KVM_STATS_TYPE_CUMULATIVE (0x0 << KVM_STATS_TYPE_SHIFT) 5985 #define KVM_STATS_TYPE_INSTANT (0x1 << KVM_STATS_TYPE_SHIFT) 5986 #define KVM_STATS_TYPE_PEAK (0x2 << KVM_STATS_TYPE_SHIFT) 5987 #define KVM_STATS_TYPE_LINEAR_HIST (0x3 << KVM_STATS_TYPE_SHIFT) 5988 #define KVM_STATS_TYPE_LOG_HIST (0x4 << KVM_STATS_TYPE_SHIFT) 5989 #define KVM_STATS_TYPE_MAX KVM_STATS_TYPE_LOG_HIST 5990 5991 #define KVM_STATS_UNIT_SHIFT 4 5992 #define KVM_STATS_UNIT_MASK (0xF << KVM_STATS_UNIT_SHIFT) 5993 #define KVM_STATS_UNIT_NONE (0x0 << KVM_STATS_UNIT_SHIFT) 5994 #define KVM_STATS_UNIT_BYTES (0x1 << KVM_STATS_UNIT_SHIFT) 5995 #define KVM_STATS_UNIT_SECONDS (0x2 << KVM_STATS_UNIT_SHIFT) 5996 #define KVM_STATS_UNIT_CYCLES (0x3 << KVM_STATS_UNIT_SHIFT) 5997 #define KVM_STATS_UNIT_BOOLEAN (0x4 << KVM_STATS_UNIT_SHIFT) 5998 #define KVM_STATS_UNIT_MAX KVM_STATS_UNIT_BOOLEAN 5999 6000 #define KVM_STATS_BASE_SHIFT 8 6001 #define KVM_STATS_BASE_MASK (0xF << KVM_STATS_BASE_SHIFT) 6002 #define KVM_STATS_BASE_POW10 (0x0 << KVM_STATS_BASE_SHIFT) 6003 #define KVM_STATS_BASE_POW2 (0x1 << KVM_STATS_BASE_SHIFT) 6004 #define KVM_STATS_BASE_MAX KVM_STATS_BASE_POW2 6005 6006 struct kvm_stats_desc { 6007 __u32 flags; 6008 __s16 exponent; 6009 __u16 size; 6010 __u32 offset; 6011 __u32 bucket_size; 6012 char name[]; 6013 }; 6014 6015The ``flags`` field contains the type and unit of the statistics data described 6016by this descriptor. Its endianness is CPU native. 6017The following flags are supported: 6018 6019Bits 0-3 of ``flags`` encode the type: 6020 6021 * ``KVM_STATS_TYPE_CUMULATIVE`` 6022 The statistics reports a cumulative count. The value of data can only be increased. 6023 Most of the counters used in KVM are of this type. 6024 The corresponding ``size`` field for this type is always 1. 6025 All cumulative statistics data are read/write. 6026 * ``KVM_STATS_TYPE_INSTANT`` 6027 The statistics reports an instantaneous value. Its value can be increased or 6028 decreased. This type is usually used as a measurement of some resources, 6029 like the number of dirty pages, the number of large pages, etc. 6030 All instant statistics are read only. 6031 The corresponding ``size`` field for this type is always 1. 6032 * ``KVM_STATS_TYPE_PEAK`` 6033 The statistics data reports a peak value, for example the maximum number 6034 of items in a hash table bucket, the longest time waited and so on. 6035 The value of data can only be increased. 6036 The corresponding ``size`` field for this type is always 1. 6037 * ``KVM_STATS_TYPE_LINEAR_HIST`` 6038 The statistic is reported as a linear histogram. The number of 6039 buckets is specified by the ``size`` field. The size of buckets is specified 6040 by the ``hist_param`` field. The range of the Nth bucket (1 <= N < ``size``) 6041 is [``hist_param``*(N-1), ``hist_param``*N), while the range of the last 6042 bucket is [``hist_param``*(``size``-1), +INF). (+INF means positive infinity 6043 value.) 6044 * ``KVM_STATS_TYPE_LOG_HIST`` 6045 The statistic is reported as a logarithmic histogram. The number of 6046 buckets is specified by the ``size`` field. The range of the first bucket is 6047 [0, 1), while the range of the last bucket is [pow(2, ``size``-2), +INF). 6048 Otherwise, The Nth bucket (1 < N < ``size``) covers 6049 [pow(2, N-2), pow(2, N-1)). 6050 6051Bits 4-7 of ``flags`` encode the unit: 6052 6053 * ``KVM_STATS_UNIT_NONE`` 6054 There is no unit for the value of statistics data. This usually means that 6055 the value is a simple counter of an event. 6056 * ``KVM_STATS_UNIT_BYTES`` 6057 It indicates that the statistics data is used to measure memory size, in the 6058 unit of Byte, KiByte, MiByte, GiByte, etc. The unit of the data is 6059 determined by the ``exponent`` field in the descriptor. 6060 * ``KVM_STATS_UNIT_SECONDS`` 6061 It indicates that the statistics data is used to measure time or latency. 6062 * ``KVM_STATS_UNIT_CYCLES`` 6063 It indicates that the statistics data is used to measure CPU clock cycles. 6064 * ``KVM_STATS_UNIT_BOOLEAN`` 6065 It indicates that the statistic will always be either 0 or 1. Boolean 6066 statistics of "peak" type will never go back from 1 to 0. Boolean 6067 statistics can be linear histograms (with two buckets) but not logarithmic 6068 histograms. 6069 6070Note that, in the case of histograms, the unit applies to the bucket 6071ranges, while the bucket value indicates how many samples fell in the 6072bucket's range. 6073 6074Bits 8-11 of ``flags``, together with ``exponent``, encode the scale of the 6075unit: 6076 6077 * ``KVM_STATS_BASE_POW10`` 6078 The scale is based on power of 10. It is used for measurement of time and 6079 CPU clock cycles. For example, an exponent of -9 can be used with 6080 ``KVM_STATS_UNIT_SECONDS`` to express that the unit is nanoseconds. 6081 * ``KVM_STATS_BASE_POW2`` 6082 The scale is based on power of 2. It is used for measurement of memory size. 6083 For example, an exponent of 20 can be used with ``KVM_STATS_UNIT_BYTES`` to 6084 express that the unit is MiB. 6085 6086The ``size`` field is the number of values of this statistics data. Its 6087value is usually 1 for most of simple statistics. 1 means it contains an 6088unsigned 64bit data. 6089 6090The ``offset`` field is the offset from the start of Data Block to the start of 6091the corresponding statistics data. 6092 6093The ``bucket_size`` field is used as a parameter for histogram statistics data. 6094It is only used by linear histogram statistics data, specifying the size of a 6095bucket in the unit expressed by bits 4-11 of ``flags`` together with ``exponent``. 6096 6097The ``name`` field is the name string of the statistics data. The name string 6098starts at the end of ``struct kvm_stats_desc``. The maximum length including 6099the trailing ``'\0'``, is indicated by ``name_size`` in the header. 6100 6101The Stats Data block contains an array of 64-bit values in the same order 6102as the descriptors in Descriptors block. 6103 61044.134 KVM_GET_XSAVE2 6105-------------------- 6106 6107:Capability: KVM_CAP_XSAVE2 6108:Architectures: x86 6109:Type: vcpu ioctl 6110:Parameters: struct kvm_xsave (out) 6111:Returns: 0 on success, -1 on error 6112 6113 6114:: 6115 6116 struct kvm_xsave { 6117 __u32 region[1024]; 6118 __u32 extra[0]; 6119 }; 6120 6121This ioctl would copy current vcpu's xsave struct to the userspace. It 6122copies as many bytes as are returned by KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2) 6123when invoked on the vm file descriptor. The size value returned by 6124KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2) will always be at least 4096. 6125Currently, it is only greater than 4096 if a dynamic feature has been 6126enabled with ``arch_prctl()``, but this may change in the future. 6127 6128The offsets of the state save areas in struct kvm_xsave follow the contents 6129of CPUID leaf 0xD on the host. 6130 61314.135 KVM_XEN_HVM_EVTCHN_SEND 6132----------------------------- 6133 6134:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_EVTCHN_SEND 6135:Architectures: x86 6136:Type: vm ioctl 6137:Parameters: struct kvm_irq_routing_xen_evtchn 6138:Returns: 0 on success, < 0 on error 6139 6140 6141:: 6142 6143 struct kvm_irq_routing_xen_evtchn { 6144 __u32 port; 6145 __u32 vcpu; 6146 __u32 priority; 6147 }; 6148 6149This ioctl injects an event channel interrupt directly to the guest vCPU. 6150 61514.136 KVM_S390_PV_CPU_COMMAND 6152----------------------------- 6153 6154:Capability: KVM_CAP_S390_PROTECTED_DUMP 6155:Architectures: s390 6156:Type: vcpu ioctl 6157:Parameters: none 6158:Returns: 0 on success, < 0 on error 6159 6160This ioctl closely mirrors `KVM_S390_PV_COMMAND` but handles requests 6161for vcpus. It re-uses the kvm_s390_pv_dmp struct and hence also shares 6162the command ids. 6163 6164**command:** 6165 6166KVM_PV_DUMP 6167 Presents an API that provides calls which facilitate dumping a vcpu 6168 of a protected VM. 6169 6170**subcommand:** 6171 6172KVM_PV_DUMP_CPU 6173 Provides encrypted dump data like register values. 6174 The length of the returned data is provided by uv_info.guest_cpu_stor_len. 6175 61764.137 KVM_S390_ZPCI_OP 6177---------------------- 6178 6179:Capability: KVM_CAP_S390_ZPCI_OP 6180:Architectures: s390 6181:Type: vm ioctl 6182:Parameters: struct kvm_s390_zpci_op (in) 6183:Returns: 0 on success, <0 on error 6184 6185Used to manage hardware-assisted virtualization features for zPCI devices. 6186 6187Parameters are specified via the following structure:: 6188 6189 struct kvm_s390_zpci_op { 6190 /* in */ 6191 __u32 fh; /* target device */ 6192 __u8 op; /* operation to perform */ 6193 __u8 pad[3]; 6194 union { 6195 /* for KVM_S390_ZPCIOP_REG_AEN */ 6196 struct { 6197 __u64 ibv; /* Guest addr of interrupt bit vector */ 6198 __u64 sb; /* Guest addr of summary bit */ 6199 __u32 flags; 6200 __u32 noi; /* Number of interrupts */ 6201 __u8 isc; /* Guest interrupt subclass */ 6202 __u8 sbo; /* Offset of guest summary bit vector */ 6203 __u16 pad; 6204 } reg_aen; 6205 __u64 reserved[8]; 6206 } u; 6207 }; 6208 6209The type of operation is specified in the "op" field. 6210KVM_S390_ZPCIOP_REG_AEN is used to register the VM for adapter event 6211notification interpretation, which will allow firmware delivery of adapter 6212events directly to the vm, with KVM providing a backup delivery mechanism; 6213KVM_S390_ZPCIOP_DEREG_AEN is used to subsequently disable interpretation of 6214adapter event notifications. 6215 6216The target zPCI function must also be specified via the "fh" field. For the 6217KVM_S390_ZPCIOP_REG_AEN operation, additional information to establish firmware 6218delivery must be provided via the "reg_aen" struct. 6219 6220The "pad" and "reserved" fields may be used for future extensions and should be 6221set to 0s by userspace. 6222 62234.138 KVM_ARM_SET_COUNTER_OFFSET 6224-------------------------------- 6225 6226:Capability: KVM_CAP_COUNTER_OFFSET 6227:Architectures: arm64 6228:Type: vm ioctl 6229:Parameters: struct kvm_arm_counter_offset (in) 6230:Returns: 0 on success, < 0 on error 6231 6232This capability indicates that userspace is able to apply a single VM-wide 6233offset to both the virtual and physical counters as viewed by the guest 6234using the KVM_ARM_SET_CNT_OFFSET ioctl and the following data structure: 6235 6236:: 6237 6238 struct kvm_arm_counter_offset { 6239 __u64 counter_offset; 6240 __u64 reserved; 6241 }; 6242 6243The offset describes a number of counter cycles that are subtracted from 6244both virtual and physical counter views (similar to the effects of the 6245CNTVOFF_EL2 and CNTPOFF_EL2 system registers, but only global). The offset 6246always applies to all vcpus (already created or created after this ioctl) 6247for this VM. 6248 6249It is userspace's responsibility to compute the offset based, for example, 6250on previous values of the guest counters. 6251 6252Any value other than 0 for the "reserved" field may result in an error 6253(-EINVAL) being returned. This ioctl can also return -EBUSY if any vcpu 6254ioctl is issued concurrently. 6255 6256Note that using this ioctl results in KVM ignoring subsequent userspace 6257writes to the CNTVCT_EL0 and CNTPCT_EL0 registers using the SET_ONE_REG 6258interface. No error will be returned, but the resulting offset will not be 6259applied. 6260 6261.. _KVM_ARM_GET_REG_WRITABLE_MASKS: 6262 62634.139 KVM_ARM_GET_REG_WRITABLE_MASKS 6264------------------------------------ 6265 6266:Capability: KVM_CAP_ARM_SUPPORTED_REG_MASK_RANGES 6267:Architectures: arm64 6268:Type: vm ioctl 6269:Parameters: struct reg_mask_range (in/out) 6270:Returns: 0 on success, < 0 on error 6271 6272 6273:: 6274 6275 #define KVM_ARM_FEATURE_ID_RANGE 0 6276 #define KVM_ARM_FEATURE_ID_RANGE_SIZE (3 * 8 * 8) 6277 6278 struct reg_mask_range { 6279 __u64 addr; /* Pointer to mask array */ 6280 __u32 range; /* Requested range */ 6281 __u32 reserved[13]; 6282 }; 6283 6284This ioctl copies the writable masks for a selected range of registers to 6285userspace. 6286 6287The ``addr`` field is a pointer to the destination array where KVM copies 6288the writable masks. 6289 6290The ``range`` field indicates the requested range of registers. 6291``KVM_CHECK_EXTENSION`` for the ``KVM_CAP_ARM_SUPPORTED_REG_MASK_RANGES`` 6292capability returns the supported ranges, expressed as a set of flags. Each 6293flag's bit index represents a possible value for the ``range`` field. 6294All other values are reserved for future use and KVM may return an error. 6295 6296The ``reserved[13]`` array is reserved for future use and should be 0, or 6297KVM may return an error. 6298 6299KVM_ARM_FEATURE_ID_RANGE (0) 6300^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 6301 6302The Feature ID range is defined as the AArch64 System register space with 6303op0==3, op1=={0, 1, 3}, CRn==0, CRm=={0-7}, op2=={0-7}. 6304 6305The mask returned array pointed to by ``addr`` is indexed by the macro 6306``ARM64_FEATURE_ID_RANGE_IDX(op0, op1, crn, crm, op2)``, allowing userspace 6307to know what fields can be changed for the system register described by 6308``op0, op1, crn, crm, op2``. KVM rejects ID register values that describe a 6309superset of the features supported by the system. 6310 63114.140 KVM_SET_USER_MEMORY_REGION2 6312--------------------------------- 6313 6314:Capability: KVM_CAP_USER_MEMORY2 6315:Architectures: all 6316:Type: vm ioctl 6317:Parameters: struct kvm_userspace_memory_region2 (in) 6318:Returns: 0 on success, -1 on error 6319 6320KVM_SET_USER_MEMORY_REGION2 is an extension to KVM_SET_USER_MEMORY_REGION that 6321allows mapping guest_memfd memory into a guest. All fields shared with 6322KVM_SET_USER_MEMORY_REGION identically. Userspace can set KVM_MEM_GUEST_MEMFD 6323in flags to have KVM bind the memory region to a given guest_memfd range of 6324[guest_memfd_offset, guest_memfd_offset + memory_size]. The target guest_memfd 6325must point at a file created via KVM_CREATE_GUEST_MEMFD on the current VM, and 6326the target range must not be bound to any other memory region. All standard 6327bounds checks apply (use common sense). 6328 6329:: 6330 6331 struct kvm_userspace_memory_region2 { 6332 __u32 slot; 6333 __u32 flags; 6334 __u64 guest_phys_addr; 6335 __u64 memory_size; /* bytes */ 6336 __u64 userspace_addr; /* start of the userspace allocated memory */ 6337 __u64 guest_memfd_offset; 6338 __u32 guest_memfd; 6339 __u32 pad1; 6340 __u64 pad2[14]; 6341 }; 6342 6343A KVM_MEM_GUEST_MEMFD region _must_ have a valid guest_memfd (private memory) and 6344userspace_addr (shared memory). However, "valid" for userspace_addr simply 6345means that the address itself must be a legal userspace address. The backing 6346mapping for userspace_addr is not required to be valid/populated at the time of 6347KVM_SET_USER_MEMORY_REGION2, e.g. shared memory can be lazily mapped/allocated 6348on-demand. 6349 6350When mapping a gfn into the guest, KVM selects shared vs. private, i.e consumes 6351userspace_addr vs. guest_memfd, based on the gfn's KVM_MEMORY_ATTRIBUTE_PRIVATE 6352state. At VM creation time, all memory is shared, i.e. the PRIVATE attribute 6353is '0' for all gfns. Userspace can control whether memory is shared/private by 6354toggling KVM_MEMORY_ATTRIBUTE_PRIVATE via KVM_SET_MEMORY_ATTRIBUTES as needed. 6355 6356S390: 6357^^^^^ 6358 6359Returns -EINVAL if the VM has the KVM_VM_S390_UCONTROL flag set. 6360Returns -EINVAL if called on a protected VM. 6361 63624.141 KVM_SET_MEMORY_ATTRIBUTES 6363------------------------------- 6364 6365:Capability: KVM_CAP_MEMORY_ATTRIBUTES 6366:Architectures: x86 6367:Type: vm ioctl 6368:Parameters: struct kvm_memory_attributes (in) 6369:Returns: 0 on success, <0 on error 6370 6371KVM_SET_MEMORY_ATTRIBUTES allows userspace to set memory attributes for a range 6372of guest physical memory. 6373 6374:: 6375 6376 struct kvm_memory_attributes { 6377 __u64 address; 6378 __u64 size; 6379 __u64 attributes; 6380 __u64 flags; 6381 }; 6382 6383 #define KVM_MEMORY_ATTRIBUTE_PRIVATE (1ULL << 3) 6384 6385The address and size must be page aligned. The supported attributes can be 6386retrieved via ioctl(KVM_CHECK_EXTENSION) on KVM_CAP_MEMORY_ATTRIBUTES. If 6387executed on a VM, KVM_CAP_MEMORY_ATTRIBUTES precisely returns the attributes 6388supported by that VM. If executed at system scope, KVM_CAP_MEMORY_ATTRIBUTES 6389returns all attributes supported by KVM. The only attribute defined at this 6390time is KVM_MEMORY_ATTRIBUTE_PRIVATE, which marks the associated gfn as being 6391guest private memory. 6392 6393Note, there is no "get" API. Userspace is responsible for explicitly tracking 6394the state of a gfn/page as needed. 6395 6396The "flags" field is reserved for future extensions and must be '0'. 6397 63984.142 KVM_CREATE_GUEST_MEMFD 6399---------------------------- 6400 6401:Capability: KVM_CAP_GUEST_MEMFD 6402:Architectures: none 6403:Type: vm ioctl 6404:Parameters: struct kvm_create_guest_memfd(in) 6405:Returns: A file descriptor on success, <0 on error 6406 6407KVM_CREATE_GUEST_MEMFD creates an anonymous file and returns a file descriptor 6408that refers to it. guest_memfd files are roughly analogous to files created 6409via memfd_create(), e.g. guest_memfd files live in RAM, have volatile storage, 6410and are automatically released when the last reference is dropped. Unlike 6411"regular" memfd_create() files, guest_memfd files are bound to their owning 6412virtual machine (see below), cannot be mapped, read, or written by userspace, 6413and cannot be resized (guest_memfd files do however support PUNCH_HOLE). 6414 6415:: 6416 6417 struct kvm_create_guest_memfd { 6418 __u64 size; 6419 __u64 flags; 6420 __u64 reserved[6]; 6421 }; 6422 6423Conceptually, the inode backing a guest_memfd file represents physical memory, 6424i.e. is coupled to the virtual machine as a thing, not to a "struct kvm". The 6425file itself, which is bound to a "struct kvm", is that instance's view of the 6426underlying memory, e.g. effectively provides the translation of guest addresses 6427to host memory. This allows for use cases where multiple KVM structures are 6428used to manage a single virtual machine, e.g. when performing intrahost 6429migration of a virtual machine. 6430 6431KVM currently only supports mapping guest_memfd via KVM_SET_USER_MEMORY_REGION2, 6432and more specifically via the guest_memfd and guest_memfd_offset fields in 6433"struct kvm_userspace_memory_region2", where guest_memfd_offset is the offset 6434into the guest_memfd instance. For a given guest_memfd file, there can be at 6435most one mapping per page, i.e. binding multiple memory regions to a single 6436guest_memfd range is not allowed (any number of memory regions can be bound to 6437a single guest_memfd file, but the bound ranges must not overlap). 6438 6439The capability KVM_CAP_GUEST_MEMFD_FLAGS enumerates the `flags` that can be 6440specified via KVM_CREATE_GUEST_MEMFD. Currently defined flags: 6441 6442 ============================ ================================================ 6443 GUEST_MEMFD_FLAG_MMAP Enable using mmap() on the guest_memfd file 6444 descriptor. 6445 GUEST_MEMFD_FLAG_INIT_SHARED Make all memory in the file shared during 6446 KVM_CREATE_GUEST_MEMFD (memory files created 6447 without INIT_SHARED will be marked private). 6448 Shared memory can be faulted into host userspace 6449 page tables. Private memory cannot. 6450 ============================ ================================================ 6451 6452When the KVM MMU performs a PFN lookup to service a guest fault and the backing 6453guest_memfd has the GUEST_MEMFD_FLAG_MMAP set, then the fault will always be 6454consumed from guest_memfd, regardless of whether it is a shared or a private 6455fault. 6456 6457See KVM_SET_USER_MEMORY_REGION2 for additional details. 6458 64594.143 KVM_PRE_FAULT_MEMORY 6460--------------------------- 6461 6462:Capability: KVM_CAP_PRE_FAULT_MEMORY 6463:Architectures: none 6464:Type: vcpu ioctl 6465:Parameters: struct kvm_pre_fault_memory (in/out) 6466:Returns: 0 if at least one page is processed, < 0 on error 6467 6468Errors: 6469 6470 ========== =============================================================== 6471 EINVAL The specified `gpa` and `size` were invalid (e.g. not 6472 page aligned, causes an overflow, or size is zero). 6473 ENOENT The specified `gpa` is outside defined memslots. 6474 EINTR An unmasked signal is pending and no page was processed. 6475 EFAULT The parameter address was invalid. 6476 EOPNOTSUPP Mapping memory for a GPA is unsupported by the 6477 hypervisor, and/or for the current vCPU state/mode. 6478 EIO unexpected error conditions (also causes a WARN) 6479 ========== =============================================================== 6480 6481:: 6482 6483 struct kvm_pre_fault_memory { 6484 /* in/out */ 6485 __u64 gpa; 6486 __u64 size; 6487 /* in */ 6488 __u64 flags; 6489 __u64 padding[5]; 6490 }; 6491 6492KVM_PRE_FAULT_MEMORY populates KVM's stage-2 page tables used to map memory 6493for the current vCPU state. KVM maps memory as if the vCPU generated a 6494stage-2 read page fault, e.g. faults in memory as needed, but doesn't break 6495CoW. However, KVM does not mark any newly created stage-2 PTE as Accessed. 6496 6497In the case of confidential VM types where there is an initial set up of 6498private guest memory before the guest is 'finalized'/measured, this ioctl 6499should only be issued after completing all the necessary setup to put the 6500guest into a 'finalized' state so that the above semantics can be reliably 6501ensured. 6502 6503In some cases, multiple vCPUs might share the page tables. In this 6504case, the ioctl can be called in parallel. 6505 6506When the ioctl returns, the input values are updated to point to the 6507remaining range. If `size` > 0 on return, the caller can just issue 6508the ioctl again with the same `struct kvm_map_memory` argument. 6509 6510Shadow page tables cannot support this ioctl because they 6511are indexed by virtual address or nested guest physical address. 6512Calling this ioctl when the guest is using shadow page tables (for 6513example because it is running a nested guest with nested page tables) 6514will fail with `EOPNOTSUPP` even if `KVM_CHECK_EXTENSION` reports 6515the capability to be present. 6516 6517`flags` must currently be zero. 6518 65194.144 KVM_S390_KEYOP 6520-------------------- 6521 6522:Capability: KVM_CAP_S390_KEYOP 6523:Architectures: s390 6524:Type: vm ioctl 6525:Parameters: struct kvm_s390_keyop (in/out) 6526:Returns: 0 in case of success, < 0 on error 6527 6528The specified key operation is performed on the given guest address. The 6529previous storage key (or the relevant part thereof) will be returned in 6530`key`. 6531 6532:: 6533 6534 struct kvm_s390_keyop { 6535 __u64 guest_addr; 6536 __u8 key; 6537 __u8 operation; 6538 }; 6539 6540Currently supported values for ``operation``: 6541 6542KVM_S390_KEYOP_ISKE 6543 Returns the storage key for the guest address ``guest_addr`` in ``key``. 6544 6545KVM_S390_KEYOP_RRBE 6546 Resets the reference bit for the guest address ``guest_addr``, returning the 6547 R and C bits of the old storage key in ``key``; the remaining fields of 6548 the storage key will be set to 0. 6549 6550KVM_S390_KEYOP_SSKE 6551 Sets the storage key for the guest address ``guest_addr`` to the key 6552 specified in ``key``, returning the previous value in ``key``. 6553 6554.. _kvm_run: 6555 65565. The kvm_run structure 6557======================== 6558 6559Application code obtains a pointer to the kvm_run structure by 6560mmap()ing a vcpu fd. From that point, application code can control 6561execution by changing fields in kvm_run prior to calling the KVM_RUN 6562ioctl, and obtain information about the reason KVM_RUN returned by 6563looking up structure members. 6564 6565:: 6566 6567 struct kvm_run { 6568 /* in */ 6569 __u8 request_interrupt_window; 6570 6571Request that KVM_RUN return when it becomes possible to inject external 6572interrupts into the guest. Useful in conjunction with KVM_INTERRUPT. 6573 6574:: 6575 6576 __u8 immediate_exit; 6577 6578This field is polled once when KVM_RUN starts; if non-zero, KVM_RUN 6579exits immediately, returning -EINTR. In the common scenario where a 6580signal is used to "kick" a VCPU out of KVM_RUN, this field can be used 6581to avoid usage of KVM_SET_SIGNAL_MASK, which has worse scalability. 6582Rather than blocking the signal outside KVM_RUN, userspace can set up 6583a signal handler that sets run->immediate_exit to a non-zero value. 6584 6585This field is ignored if KVM_CAP_IMMEDIATE_EXIT is not available. 6586 6587:: 6588 6589 __u8 padding1[6]; 6590 6591 /* out */ 6592 __u32 exit_reason; 6593 6594When KVM_RUN has returned successfully (return value 0), this informs 6595application code why KVM_RUN has returned. Allowable values for this 6596field are detailed below. 6597 6598:: 6599 6600 __u8 ready_for_interrupt_injection; 6601 6602If request_interrupt_window has been specified, this field indicates 6603an interrupt can be injected now with KVM_INTERRUPT. 6604 6605:: 6606 6607 __u8 if_flag; 6608 6609The value of the current interrupt flag. Only valid if in-kernel 6610local APIC is not used. 6611 6612:: 6613 6614 __u16 flags; 6615 6616More architecture-specific flags detailing state of the VCPU that may 6617affect the device's behavior. Current defined flags:: 6618 6619 /* x86, set if the VCPU is in system management mode */ 6620 #define KVM_RUN_X86_SMM (1 << 0) 6621 /* x86, set if bus lock detected in VM */ 6622 #define KVM_RUN_X86_BUS_LOCK (1 << 1) 6623 /* x86, set if the VCPU is executing a nested (L2) guest */ 6624 #define KVM_RUN_X86_GUEST_MODE (1 << 2) 6625 6626 /* arm64, set for KVM_EXIT_DEBUG */ 6627 #define KVM_DEBUG_ARCH_HSR_HIGH_VALID (1 << 0) 6628 6629:: 6630 6631 /* in (pre_kvm_run), out (post_kvm_run) */ 6632 __u64 cr8; 6633 6634The value of the cr8 register. Only valid if in-kernel local APIC is 6635not used. Both input and output. 6636 6637:: 6638 6639 __u64 apic_base; 6640 6641The value of the APIC BASE msr. Only valid if in-kernel local 6642APIC is not used. Both input and output. 6643 6644:: 6645 6646 union { 6647 /* KVM_EXIT_UNKNOWN */ 6648 struct { 6649 __u64 hardware_exit_reason; 6650 } hw; 6651 6652If exit_reason is KVM_EXIT_UNKNOWN, the vcpu has exited due to unknown 6653reasons. Further architecture-specific information is available in 6654hardware_exit_reason. 6655 6656:: 6657 6658 /* KVM_EXIT_FAIL_ENTRY */ 6659 struct { 6660 __u64 hardware_entry_failure_reason; 6661 __u32 cpu; /* if KVM_LAST_CPU */ 6662 } fail_entry; 6663 6664If exit_reason is KVM_EXIT_FAIL_ENTRY, the vcpu could not be run due 6665to unknown reasons. Further architecture-specific information is 6666available in hardware_entry_failure_reason. 6667 6668:: 6669 6670 /* KVM_EXIT_EXCEPTION */ 6671 struct { 6672 __u32 exception; 6673 __u32 error_code; 6674 } ex; 6675 6676Unused. 6677 6678:: 6679 6680 /* KVM_EXIT_IO */ 6681 struct { 6682 #define KVM_EXIT_IO_IN 0 6683 #define KVM_EXIT_IO_OUT 1 6684 __u8 direction; 6685 __u8 size; /* bytes */ 6686 __u16 port; 6687 __u32 count; 6688 __u64 data_offset; /* relative to kvm_run start */ 6689 } io; 6690 6691If exit_reason is KVM_EXIT_IO, then the vcpu has 6692executed a port I/O instruction which could not be satisfied by kvm. 6693data_offset describes where the data is located (KVM_EXIT_IO_OUT) or 6694where kvm expects application code to place the data for the next 6695KVM_RUN invocation (KVM_EXIT_IO_IN). Data format is a packed array. 6696 6697:: 6698 6699 /* KVM_EXIT_DEBUG */ 6700 struct { 6701 struct kvm_debug_exit_arch arch; 6702 } debug; 6703 6704If the exit_reason is KVM_EXIT_DEBUG, then a vcpu is processing a debug event 6705for which architecture specific information is returned. 6706 6707:: 6708 6709 /* KVM_EXIT_MMIO */ 6710 struct { 6711 __u64 phys_addr; 6712 __u8 data[8]; 6713 __u32 len; 6714 __u8 is_write; 6715 } mmio; 6716 6717If exit_reason is KVM_EXIT_MMIO, then the vcpu has 6718executed a memory-mapped I/O instruction which could not be satisfied 6719by kvm. The 'data' member contains the written data if 'is_write' is 6720true, and should be filled by application code otherwise. 6721 6722The 'data' member contains, in its first 'len' bytes, the value as it would 6723appear if the VCPU performed a load or store of the appropriate width directly 6724to the byte array. 6725 6726.. note:: 6727 6728 For KVM_EXIT_IO, KVM_EXIT_MMIO, KVM_EXIT_OSI, KVM_EXIT_PAPR, KVM_EXIT_XEN, 6729 KVM_EXIT_EPR, KVM_EXIT_HYPERCALL, KVM_EXIT_TDX, 6730 KVM_EXIT_X86_RDMSR and KVM_EXIT_X86_WRMSR the corresponding 6731 operations are complete (and guest state is consistent) only after userspace 6732 has re-entered the kernel with KVM_RUN. The kernel side will first finish 6733 incomplete operations and then check for pending signals. 6734 6735 The pending state of the operation is not preserved in state which is 6736 visible to userspace, thus userspace should ensure that the operation is 6737 completed before performing a live migration. Userspace can re-enter the 6738 guest with an unmasked signal pending or with the immediate_exit field set 6739 to complete pending operations without allowing any further instructions 6740 to be executed. 6741 6742:: 6743 6744 /* KVM_EXIT_HYPERCALL */ 6745 struct { 6746 __u64 nr; 6747 __u64 args[6]; 6748 __u64 ret; 6749 __u64 flags; 6750 } hypercall; 6751 6752 6753It is strongly recommended that userspace use ``KVM_EXIT_IO`` (x86) or 6754``KVM_EXIT_MMIO`` (all except s390) to implement functionality that 6755requires a guest to interact with host userspace. 6756 6757.. note:: KVM_EXIT_IO is significantly faster than KVM_EXIT_MMIO. 6758 6759For arm64: 6760---------- 6761 6762SMCCC exits can be enabled depending on the configuration of the SMCCC 6763filter. See the Documentation/virt/kvm/devices/vm.rst 6764``KVM_ARM_SMCCC_FILTER`` for more details. 6765 6766``nr`` contains the function ID of the guest's SMCCC call. Userspace is 6767expected to use the ``KVM_GET_ONE_REG`` ioctl to retrieve the call 6768parameters from the vCPU's GPRs. 6769 6770Definition of ``flags``: 6771 - ``KVM_HYPERCALL_EXIT_SMC``: Indicates that the guest used the SMC 6772 conduit to initiate the SMCCC call. If this bit is 0 then the guest 6773 used the HVC conduit for the SMCCC call. 6774 6775 - ``KVM_HYPERCALL_EXIT_16BIT``: Indicates that the guest used a 16bit 6776 instruction to initiate the SMCCC call. If this bit is 0 then the 6777 guest used a 32bit instruction. An AArch64 guest always has this 6778 bit set to 0. 6779 6780At the point of exit, PC points to the instruction immediately following 6781the trapping instruction. 6782 6783:: 6784 6785 /* KVM_EXIT_TPR_ACCESS */ 6786 struct { 6787 __u64 rip; 6788 __u32 is_write; 6789 __u32 pad; 6790 } tpr_access; 6791 6792To be documented (KVM_TPR_ACCESS_REPORTING). 6793 6794:: 6795 6796 /* KVM_EXIT_S390_SIEIC */ 6797 struct { 6798 __u8 icptcode; 6799 __u64 mask; /* psw upper half */ 6800 __u64 addr; /* psw lower half */ 6801 __u16 ipa; 6802 __u32 ipb; 6803 } s390_sieic; 6804 6805s390 specific. 6806 6807:: 6808 6809 /* KVM_EXIT_S390_RESET */ 6810 #define KVM_S390_RESET_POR 1 6811 #define KVM_S390_RESET_CLEAR 2 6812 #define KVM_S390_RESET_SUBSYSTEM 4 6813 #define KVM_S390_RESET_CPU_INIT 8 6814 #define KVM_S390_RESET_IPL 16 6815 __u64 s390_reset_flags; 6816 6817s390 specific. 6818 6819:: 6820 6821 /* KVM_EXIT_S390_UCONTROL */ 6822 struct { 6823 __u64 trans_exc_code; 6824 __u32 pgm_code; 6825 } s390_ucontrol; 6826 6827s390 specific. A page fault has occurred for a user controlled virtual 6828machine (KVM_VM_S390_UNCONTROL) on its host page table that cannot be 6829resolved by the kernel. 6830The program code and the translation exception code that were placed 6831in the cpu's lowcore are presented here as defined by the z Architecture 6832Principles of Operation Book in the Chapter for Dynamic Address Translation 6833(DAT) 6834 6835:: 6836 6837 /* KVM_EXIT_DCR */ 6838 struct { 6839 __u32 dcrn; 6840 __u32 data; 6841 __u8 is_write; 6842 } dcr; 6843 6844Deprecated - was used for 440 KVM. 6845 6846:: 6847 6848 /* KVM_EXIT_OSI */ 6849 struct { 6850 __u64 gprs[32]; 6851 } osi; 6852 6853MOL uses a special hypercall interface it calls 'OSI'. To enable it, we catch 6854hypercalls and exit with this exit struct that contains all the guest gprs. 6855 6856If exit_reason is KVM_EXIT_OSI, then the vcpu has triggered such a hypercall. 6857Userspace can now handle the hypercall and when it's done modify the gprs as 6858necessary. Upon guest entry all guest GPRs will then be replaced by the values 6859in this struct. 6860 6861:: 6862 6863 /* KVM_EXIT_PAPR_HCALL */ 6864 struct { 6865 __u64 nr; 6866 __u64 ret; 6867 __u64 args[9]; 6868 } papr_hcall; 6869 6870This is used on 64-bit PowerPC when emulating a pSeries partition, 6871e.g. with the 'pseries' machine type in qemu. It occurs when the 6872guest does a hypercall using the 'sc 1' instruction. The 'nr' field 6873contains the hypercall number (from the guest R3), and 'args' contains 6874the arguments (from the guest R4 - R12). Userspace should put the 6875return code in 'ret' and any extra returned values in args[]. 6876The possible hypercalls are defined in the Power Architecture Platform 6877Requirements (PAPR) document available from www.power.org (free 6878developer registration required to access it). 6879 6880:: 6881 6882 /* KVM_EXIT_S390_TSCH */ 6883 struct { 6884 __u16 subchannel_id; 6885 __u16 subchannel_nr; 6886 __u32 io_int_parm; 6887 __u32 io_int_word; 6888 __u32 ipb; 6889 __u8 dequeued; 6890 } s390_tsch; 6891 6892s390 specific. This exit occurs when KVM_CAP_S390_CSS_SUPPORT has been enabled 6893and TEST SUBCHANNEL was intercepted. If dequeued is set, a pending I/O 6894interrupt for the target subchannel has been dequeued and subchannel_id, 6895subchannel_nr, io_int_parm and io_int_word contain the parameters for that 6896interrupt. ipb is needed for instruction parameter decoding. 6897 6898:: 6899 6900 /* KVM_EXIT_EPR */ 6901 struct { 6902 __u32 epr; 6903 } epr; 6904 6905On FSL BookE PowerPC chips, the interrupt controller has a fast patch 6906interrupt acknowledge path to the core. When the core successfully 6907delivers an interrupt, it automatically populates the EPR register with 6908the interrupt vector number and acknowledges the interrupt inside 6909the interrupt controller. 6910 6911In case the interrupt controller lives in user space, we need to do 6912the interrupt acknowledge cycle through it to fetch the next to be 6913delivered interrupt vector using this exit. 6914 6915It gets triggered whenever both KVM_CAP_PPC_EPR are enabled and an 6916external interrupt has just been delivered into the guest. User space 6917should put the acknowledged interrupt vector into the 'epr' field. 6918 6919:: 6920 6921 /* KVM_EXIT_SYSTEM_EVENT */ 6922 struct { 6923 #define KVM_SYSTEM_EVENT_SHUTDOWN 1 6924 #define KVM_SYSTEM_EVENT_RESET 2 6925 #define KVM_SYSTEM_EVENT_CRASH 3 6926 #define KVM_SYSTEM_EVENT_WAKEUP 4 6927 #define KVM_SYSTEM_EVENT_SUSPEND 5 6928 #define KVM_SYSTEM_EVENT_SEV_TERM 6 6929 #define KVM_SYSTEM_EVENT_TDX_FATAL 7 6930 __u32 type; 6931 __u32 ndata; 6932 __u64 data[16]; 6933 } system_event; 6934 6935If exit_reason is KVM_EXIT_SYSTEM_EVENT then the vcpu has triggered 6936a system-level event using some architecture specific mechanism (hypercall 6937or some special instruction). In case of ARM64, this is triggered using 6938HVC instruction based PSCI call from the vcpu. 6939 6940The 'type' field describes the system-level event type. 6941Valid values for 'type' are: 6942 6943 - KVM_SYSTEM_EVENT_SHUTDOWN -- the guest has requested a shutdown of the 6944 VM. Userspace is not obliged to honour this, and if it does honour 6945 this does not need to destroy the VM synchronously (ie it may call 6946 KVM_RUN again before shutdown finally occurs). 6947 - KVM_SYSTEM_EVENT_RESET -- the guest has requested a reset of the VM. 6948 As with SHUTDOWN, userspace can choose to ignore the request, or 6949 to schedule the reset to occur in the future and may call KVM_RUN again. 6950 - KVM_SYSTEM_EVENT_CRASH -- the guest crash occurred and the guest 6951 has requested a crash condition maintenance. Userspace can choose 6952 to ignore the request, or to gather VM memory core dump and/or 6953 reset/shutdown of the VM. 6954 - KVM_SYSTEM_EVENT_SEV_TERM -- an AMD SEV guest requested termination. 6955 The guest physical address of the guest's GHCB is stored in `data[0]`. 6956 - KVM_SYSTEM_EVENT_TDX_FATAL -- a TDX guest reported a fatal error state. 6957 KVM doesn't do any parsing or conversion, it just dumps 16 general-purpose 6958 registers to userspace, in ascending order of the 4-bit indices for x86-64 6959 general-purpose registers in instruction encoding, as defined in the Intel 6960 SDM. 6961 - KVM_SYSTEM_EVENT_WAKEUP -- the exiting vCPU is in a suspended state and 6962 KVM has recognized a wakeup event. Userspace may honor this event by 6963 marking the exiting vCPU as runnable, or deny it and call KVM_RUN again. 6964 - KVM_SYSTEM_EVENT_SUSPEND -- the guest has requested a suspension of 6965 the VM. 6966 6967If KVM_CAP_SYSTEM_EVENT_DATA is present, the 'data' field can contain 6968architecture specific information for the system-level event. Only 6969the first `ndata` items (possibly zero) of the data array are valid. 6970 6971 - for arm64, data[0] is set to KVM_SYSTEM_EVENT_RESET_FLAG_PSCI_RESET2 if 6972 the guest issued a SYSTEM_RESET2 call according to v1.1 of the PSCI 6973 specification. 6974 6975 - for arm64, data[0] is set to KVM_SYSTEM_EVENT_SHUTDOWN_FLAG_PSCI_OFF2 6976 if the guest issued a SYSTEM_OFF2 call according to v1.3 of the PSCI 6977 specification. 6978 6979 - for RISC-V, data[0] is set to the value of the second argument of the 6980 ``sbi_system_reset`` call. 6981 6982Previous versions of Linux defined a `flags` member in this struct. The 6983field is now aliased to `data[0]`. Userspace can assume that it is only 6984written if ndata is greater than 0. 6985 6986For arm/arm64: 6987-------------- 6988 6989KVM_SYSTEM_EVENT_SUSPEND exits are enabled with the 6990KVM_CAP_ARM_SYSTEM_SUSPEND VM capability. If a guest invokes the PSCI 6991SYSTEM_SUSPEND function, KVM will exit to userspace with this event 6992type. 6993 6994It is the sole responsibility of userspace to implement the PSCI 6995SYSTEM_SUSPEND call according to ARM DEN0022D.b 5.19 "SYSTEM_SUSPEND". 6996KVM does not change the vCPU's state before exiting to userspace, so 6997the call parameters are left in-place in the vCPU registers. 6998 6999Userspace is _required_ to take action for such an exit. It must 7000either: 7001 7002 - Honor the guest request to suspend the VM. Userspace can request 7003 in-kernel emulation of suspension by setting the calling vCPU's 7004 state to KVM_MP_STATE_SUSPENDED. Userspace must configure the vCPU's 7005 state according to the parameters passed to the PSCI function when 7006 the calling vCPU is resumed. See ARM DEN0022D.b 5.19.1 "Intended use" 7007 for details on the function parameters. 7008 7009 - Deny the guest request to suspend the VM. See ARM DEN0022D.b 5.19.2 7010 "Caller responsibilities" for possible return values. 7011 7012Hibernation using the PSCI SYSTEM_OFF2 call is enabled when PSCI v1.3 7013is enabled. If a guest invokes the PSCI SYSTEM_OFF2 function, KVM will 7014exit to userspace with the KVM_SYSTEM_EVENT_SHUTDOWN event type and with 7015data[0] set to KVM_SYSTEM_EVENT_SHUTDOWN_FLAG_PSCI_OFF2. The only 7016supported hibernate type for the SYSTEM_OFF2 function is HIBERNATE_OFF. 7017 7018:: 7019 7020 /* KVM_EXIT_IOAPIC_EOI */ 7021 struct { 7022 __u8 vector; 7023 } eoi; 7024 7025Indicates that the VCPU's in-kernel local APIC received an EOI for a 7026level-triggered IOAPIC interrupt. This exit only triggers when the 7027IOAPIC is implemented in userspace (i.e. KVM_CAP_SPLIT_IRQCHIP is enabled); 7028the userspace IOAPIC should process the EOI and retrigger the interrupt if 7029it is still asserted. Vector is the LAPIC interrupt vector for which the 7030EOI was received. 7031 7032:: 7033 7034 struct kvm_hyperv_exit { 7035 #define KVM_EXIT_HYPERV_SYNIC 1 7036 #define KVM_EXIT_HYPERV_HCALL 2 7037 #define KVM_EXIT_HYPERV_SYNDBG 3 7038 __u32 type; 7039 __u32 pad1; 7040 union { 7041 struct { 7042 __u32 msr; 7043 __u32 pad2; 7044 __u64 control; 7045 __u64 evt_page; 7046 __u64 msg_page; 7047 } synic; 7048 struct { 7049 __u64 input; 7050 __u64 result; 7051 __u64 params[2]; 7052 } hcall; 7053 struct { 7054 __u32 msr; 7055 __u32 pad2; 7056 __u64 control; 7057 __u64 status; 7058 __u64 send_page; 7059 __u64 recv_page; 7060 __u64 pending_page; 7061 } syndbg; 7062 } u; 7063 }; 7064 /* KVM_EXIT_HYPERV */ 7065 struct kvm_hyperv_exit hyperv; 7066 7067Indicates that the VCPU exits into userspace to process some tasks 7068related to Hyper-V emulation. 7069 7070Valid values for 'type' are: 7071 7072 - KVM_EXIT_HYPERV_SYNIC -- synchronously notify user-space about 7073 7074Hyper-V SynIC state change. Notification is used to remap SynIC 7075event/message pages and to enable/disable SynIC messages/events processing 7076in userspace. 7077 7078 - KVM_EXIT_HYPERV_SYNDBG -- synchronously notify user-space about 7079 7080Hyper-V Synthetic debugger state change. Notification is used to either update 7081the pending_page location or to send a control command (send the buffer located 7082in send_page or recv a buffer to recv_page). 7083 7084:: 7085 7086 /* KVM_EXIT_ARM_NISV / KVM_EXIT_ARM_LDST64B */ 7087 struct { 7088 __u64 esr_iss; 7089 __u64 fault_ipa; 7090 } arm_nisv; 7091 7092- KVM_EXIT_ARM_NISV: 7093 7094Used on arm64 systems. If a guest accesses memory not in a memslot, 7095KVM will typically return to userspace and ask it to do MMIO emulation on its 7096behalf. However, for certain classes of instructions, no instruction decode 7097(direction, length of memory access) is provided, and fetching and decoding 7098the instruction from the VM is overly complicated to live in the kernel. 7099 7100Historically, when this situation occurred, KVM would print a warning and kill 7101the VM. KVM assumed that if the guest accessed non-memslot memory, it was 7102trying to do I/O, which just couldn't be emulated, and the warning message was 7103phrased accordingly. However, what happened more often was that a guest bug 7104caused access outside the guest memory areas which should lead to a more 7105meaningful warning message and an external abort in the guest, if the access 7106did not fall within an I/O window. 7107 7108Userspace implementations can query for KVM_CAP_ARM_NISV_TO_USER, and enable 7109this capability at VM creation. Once this is done, these types of errors will 7110instead return to userspace with KVM_EXIT_ARM_NISV, with the valid bits from 7111the ESR_EL2 in the esr_iss field, and the faulting IPA in the fault_ipa field. 7112Userspace can either fix up the access if it's actually an I/O access by 7113decoding the instruction from guest memory (if it's very brave) and continue 7114executing the guest, or it can decide to suspend, dump, or restart the guest. 7115 7116Note that KVM does not skip the faulting instruction as it does for 7117KVM_EXIT_MMIO, but userspace has to emulate any change to the processing state 7118if it decides to decode and emulate the instruction. 7119 7120This feature isn't available to protected VMs, as userspace does not 7121have access to the state that is required to perform the emulation. 7122Instead, a data abort exception is directly injected in the guest. 7123Note that although KVM_CAP_ARM_NISV_TO_USER will be reported if 7124queried outside of a protected VM context, the feature will not be 7125exposed if queried on a protected VM file descriptor. 7126 7127- KVM_EXIT_ARM_LDST64B: 7128 7129Used on arm64 systems. When a guest using a LD64B, ST64B, ST64BV, ST64BV0, 7130outside of a memslot, KVM will return to userspace with KVM_EXIT_ARM_LDST64B, 7131exposing the relevant ESR_EL2 information and faulting IPA, similarly to 7132KVM_EXIT_ARM_NISV. 7133 7134Userspace is supposed to fully emulate the instructions, which includes: 7135 7136 - fetch of the operands for a store, including ACCDATA_EL1 in the case 7137 of a ST64BV0 instruction 7138 - deal with the endianness if the guest is big-endian 7139 - emulate the access, including the delivery of an exception if the 7140 access didn't succeed 7141 - provide a return value in the case of ST64BV/ST64BV0 7142 - return the data in the case of a load 7143 - increment PC if the instruction was successfully executed 7144 7145Note that there is no expectation of performance for this emulation, as it 7146involves a large number of interaction with the guest state. It is, however, 7147expected that the instruction's semantics are preserved, specially the 7148single-copy atomicity property of the 64 byte access. 7149 7150This exit reason must be handled if userspace sets ID_AA64ISAR1_EL1.LS64 to a 7151non-zero value, indicating that FEAT_LS64* is enabled. 7152 7153:: 7154 7155 /* KVM_EXIT_X86_RDMSR / KVM_EXIT_X86_WRMSR */ 7156 struct { 7157 __u8 error; /* user -> kernel */ 7158 __u8 pad[7]; 7159 __u32 reason; /* kernel -> user */ 7160 __u32 index; /* kernel -> user */ 7161 __u64 data; /* kernel <-> user */ 7162 } msr; 7163 7164Used on x86 systems. When the VM capability KVM_CAP_X86_USER_SPACE_MSR is 7165enabled, MSR accesses to registers that would invoke a #GP by KVM kernel code 7166may instead trigger a KVM_EXIT_X86_RDMSR exit for reads and KVM_EXIT_X86_WRMSR 7167exit for writes. 7168 7169The "reason" field specifies why the MSR interception occurred. Userspace will 7170only receive MSR exits when a particular reason was requested during through 7171ENABLE_CAP. Currently valid exit reasons are: 7172 7173============================ ======================================== 7174 KVM_MSR_EXIT_REASON_UNKNOWN access to MSR that is unknown to KVM 7175 KVM_MSR_EXIT_REASON_INVAL access to invalid MSRs or reserved bits 7176 KVM_MSR_EXIT_REASON_FILTER access blocked by KVM_X86_SET_MSR_FILTER 7177============================ ======================================== 7178 7179For KVM_EXIT_X86_RDMSR, the "index" field tells userspace which MSR the guest 7180wants to read. To respond to this request with a successful read, userspace 7181writes the respective data into the "data" field and must continue guest 7182execution to ensure the read data is transferred into guest register state. 7183 7184If the RDMSR request was unsuccessful, userspace indicates that with a "1" in 7185the "error" field. This will inject a #GP into the guest when the VCPU is 7186executed again. 7187 7188For KVM_EXIT_X86_WRMSR, the "index" field tells userspace which MSR the guest 7189wants to write. Once finished processing the event, userspace must continue 7190vCPU execution. If the MSR write was unsuccessful, userspace also sets the 7191"error" field to "1". 7192 7193See KVM_X86_SET_MSR_FILTER for details on the interaction with MSR filtering. 7194 7195:: 7196 7197 7198 struct kvm_xen_exit { 7199 #define KVM_EXIT_XEN_HCALL 1 7200 __u32 type; 7201 union { 7202 struct { 7203 __u32 longmode; 7204 __u32 cpl; 7205 __u64 input; 7206 __u64 result; 7207 __u64 params[6]; 7208 } hcall; 7209 } u; 7210 }; 7211 /* KVM_EXIT_XEN */ 7212 struct kvm_hyperv_exit xen; 7213 7214Indicates that the VCPU exits into userspace to process some tasks 7215related to Xen emulation. 7216 7217Valid values for 'type' are: 7218 7219 - KVM_EXIT_XEN_HCALL -- synchronously notify user-space about Xen hypercall. 7220 Userspace is expected to place the hypercall result into the appropriate 7221 field before invoking KVM_RUN again. 7222 7223:: 7224 7225 /* KVM_EXIT_RISCV_SBI */ 7226 struct { 7227 unsigned long extension_id; 7228 unsigned long function_id; 7229 unsigned long args[6]; 7230 unsigned long ret[2]; 7231 } riscv_sbi; 7232 7233If exit reason is KVM_EXIT_RISCV_SBI then it indicates that the VCPU has 7234done a SBI call which is not handled by KVM RISC-V kernel module. The details 7235of the SBI call are available in 'riscv_sbi' member of kvm_run structure. The 7236'extension_id' field of 'riscv_sbi' represents SBI extension ID whereas the 7237'function_id' field represents function ID of given SBI extension. The 'args' 7238array field of 'riscv_sbi' represents parameters for the SBI call and 'ret' 7239array field represents return values. The userspace should update the return 7240values of SBI call before resuming the VCPU. For more details on RISC-V SBI 7241spec refer, https://github.com/riscv/riscv-sbi-doc. 7242 7243:: 7244 7245 /* KVM_EXIT_MEMORY_FAULT */ 7246 struct { 7247 #define KVM_MEMORY_EXIT_FLAG_PRIVATE (1ULL << 3) 7248 __u64 flags; 7249 __u64 gpa; 7250 __u64 size; 7251 } memory_fault; 7252 7253KVM_EXIT_MEMORY_FAULT indicates the vCPU has encountered a memory fault that 7254could not be resolved by KVM. The 'gpa' and 'size' (in bytes) describe the 7255guest physical address range [gpa, gpa + size) of the fault. The 'flags' field 7256describes properties of the faulting access that are likely pertinent: 7257 7258 - KVM_MEMORY_EXIT_FLAG_PRIVATE - When set, indicates the memory fault occurred 7259 on a private memory access. When clear, indicates the fault occurred on a 7260 shared access. 7261 7262Note! KVM_EXIT_MEMORY_FAULT is unique among all KVM exit reasons in that it 7263accompanies a return code of '-1', not '0'! errno will always be set to EFAULT 7264or EHWPOISON when KVM exits with KVM_EXIT_MEMORY_FAULT, userspace should assume 7265kvm_run.exit_reason is stale/undefined for all other error numbers. 7266 7267:: 7268 7269 /* KVM_EXIT_NOTIFY */ 7270 struct { 7271 #define KVM_NOTIFY_CONTEXT_INVALID (1 << 0) 7272 __u32 flags; 7273 } notify; 7274 7275Used on x86 systems. When the VM capability KVM_CAP_X86_NOTIFY_VMEXIT is 7276enabled, a VM exit generated if no event window occurs in VM non-root mode 7277for a specified amount of time. Once KVM_X86_NOTIFY_VMEXIT_USER is set when 7278enabling the cap, it would exit to userspace with the exit reason 7279KVM_EXIT_NOTIFY for further handling. The "flags" field contains more 7280detailed info. 7281 7282The valid value for 'flags' is: 7283 7284 - KVM_NOTIFY_CONTEXT_INVALID -- the VM context is corrupted and not valid 7285 in VMCS. It would run into unknown result if resume the target VM. 7286 7287:: 7288 7289 /* KVM_EXIT_TDX */ 7290 struct { 7291 __u64 flags; 7292 __u64 nr; 7293 union { 7294 struct { 7295 u64 ret; 7296 u64 data[5]; 7297 } unknown; 7298 struct { 7299 u64 ret; 7300 u64 gpa; 7301 u64 size; 7302 } get_quote; 7303 struct { 7304 u64 ret; 7305 u64 leaf; 7306 u64 r11, r12, r13, r14; 7307 } get_tdvmcall_info; 7308 struct { 7309 u64 ret; 7310 u64 vector; 7311 } setup_event_notify; 7312 }; 7313 } tdx; 7314 7315Process a TDVMCALL from the guest. KVM forwards select TDVMCALL based 7316on the Guest-Hypervisor Communication Interface (GHCI) specification; 7317KVM bridges these requests to the userspace VMM with minimal changes, 7318placing the inputs in the union and copying them back to the guest 7319on re-entry. 7320 7321Flags are currently always zero, whereas ``nr`` contains the TDVMCALL 7322number from register R11. The remaining field of the union provide the 7323inputs and outputs of the TDVMCALL. Currently the following values of 7324``nr`` are defined: 7325 7326 * ``TDVMCALL_GET_QUOTE``: the guest has requested to generate a TD-Quote 7327 signed by a service hosting TD-Quoting Enclave operating on the host. 7328 Parameters and return value are in the ``get_quote`` field of the union. 7329 The ``gpa`` field and ``size`` specify the guest physical address 7330 (without the shared bit set) and the size of a shared-memory buffer, in 7331 which the TDX guest passes a TD Report. The ``ret`` field represents 7332 the return value of the GetQuote request. When the request has been 7333 queued successfully, the TDX guest can poll the status field in the 7334 shared-memory area to check whether the Quote generation is completed or 7335 not. When completed, the generated Quote is returned via the same buffer. 7336 7337 * ``TDVMCALL_GET_TD_VM_CALL_INFO``: the guest has requested the support 7338 status of TDVMCALLs. The output values for the given leaf should be 7339 placed in fields from ``r11`` to ``r14`` of the ``get_tdvmcall_info`` 7340 field of the union. 7341 7342 * ``TDVMCALL_SETUP_EVENT_NOTIFY_INTERRUPT``: the guest has requested to 7343 set up a notification interrupt for vector ``vector``. 7344 7345KVM may add support for more values in the future that may cause a userspace 7346exit, even without calls to ``KVM_ENABLE_CAP`` or similar. In this case, 7347it will enter with output fields already valid; in the common case, the 7348``unknown.ret`` field of the union will be ``TDVMCALL_STATUS_SUBFUNC_UNSUPPORTED``. 7349Userspace need not do anything if it does not wish to support a TDVMCALL. 7350 7351:: 7352 7353 /* KVM_EXIT_ARM_SEA */ 7354 struct { 7355 #define KVM_EXIT_ARM_SEA_FLAG_GPA_VALID (1ULL << 0) 7356 __u64 flags; 7357 __u64 esr; 7358 __u64 gva; 7359 __u64 gpa; 7360 } arm_sea; 7361 7362Used on arm64 systems. When the VM capability ``KVM_CAP_ARM_SEA_TO_USER`` is 7363enabled, a KVM exits to userspace if a guest access causes a synchronous 7364external abort (SEA) and the host APEI fails to handle the SEA. 7365 7366``esr`` is set to a sanitized value of ESR_EL2 from the exception taken to KVM, 7367consisting of the following fields: 7368 7369 - ``ESR_EL2.EC`` 7370 - ``ESR_EL2.IL`` 7371 - ``ESR_EL2.FnV`` 7372 - ``ESR_EL2.EA`` 7373 - ``ESR_EL2.CM`` 7374 - ``ESR_EL2.WNR`` 7375 - ``ESR_EL2.FSC`` 7376 - ``ESR_EL2.SET`` (when FEAT_RAS is implemented for the VM) 7377 7378``gva`` is set to the value of FAR_EL2 from the exception taken to KVM when 7379``ESR_EL2.FnV == 0``. Otherwise, the value of ``gva`` is unknown. 7380 7381``gpa`` is set to the faulting IPA from the exception taken to KVM when 7382the ``KVM_EXIT_ARM_SEA_FLAG_GPA_VALID`` flag is set. Otherwise, the value of 7383``gpa`` is unknown. 7384 7385:: 7386 7387 /* Fix the size of the union. */ 7388 char padding[256]; 7389 }; 7390 7391 /* 7392 * shared registers between kvm and userspace. 7393 * kvm_valid_regs specifies the register classes set by the host 7394 * kvm_dirty_regs specified the register classes dirtied by userspace 7395 * struct kvm_sync_regs is architecture specific, as well as the 7396 * bits for kvm_valid_regs and kvm_dirty_regs 7397 */ 7398 __u64 kvm_valid_regs; 7399 __u64 kvm_dirty_regs; 7400 union { 7401 struct kvm_sync_regs regs; 7402 char padding[SYNC_REGS_SIZE_BYTES]; 7403 } s; 7404 7405If KVM_CAP_SYNC_REGS is defined, these fields allow userspace to access 7406certain guest registers without having to call SET/GET_*REGS. Thus we can 7407avoid some system call overhead if userspace has to handle the exit. 7408Userspace can query the validity of the structure by checking 7409kvm_valid_regs for specific bits. These bits are architecture specific 7410and usually define the validity of a groups of registers. (e.g. one bit 7411for general purpose registers) 7412 7413Please note that the kernel is allowed to use the kvm_run structure as the 7414primary storage for certain register types. Therefore, the kernel may use the 7415values in kvm_run even if the corresponding bit in kvm_dirty_regs is not set. 7416 7417:: 7418 7419 /* KVM_EXIT_SNP_REQ_CERTS */ 7420 struct kvm_exit_snp_req_certs { 7421 __u64 gpa; 7422 __u64 npages; 7423 __u64 ret; 7424 }; 7425 7426KVM_EXIT_SNP_REQ_CERTS indicates an SEV-SNP guest with certificate-fetching 7427enabled (see KVM_SEV_SNP_ENABLE_REQ_CERTS) has generated an Extended Guest 7428Request NAE #VMGEXIT (SNP_GUEST_REQUEST) with message type MSG_REPORT_REQ, 7429i.e. has requested an attestation report from firmware, and would like the 7430certificate data corresponding to the attestation report signature to be 7431provided by the hypervisor as part of the request. 7432 7433To allow for userspace to provide the certificate, the 'gpa' and 'npages' 7434are forwarded verbatim from the guest request (the RAX and RBX GHCB fields 7435respectively). 'ret' is not an "output" from KVM, and is always '0' on 7436exit. KVM verifies the 'gpa' is 4KiB aligned prior to exiting to userspace, 7437but otherwise the information from the guest isn't validated. 7438 7439Upon the next KVM_RUN, e.g. after userspace has serviced the request (or not), 7440KVM will complete the #VMGEXIT, using the 'ret' field to determine whether to 7441signal success or failure to the guest, and on failure, what reason code will 7442be communicated via SW_EXITINFO2. If 'ret' is set to an unsupported value (see 7443the table below), KVM_RUN will fail with -EINVAL. For a 'ret' of 'ENOSPC', KVM 7444also consumes the 'npages' field, i.e. userspace can use the field to inform 7445the guest of the number of pages needed to hold all the certificate data. 7446 7447The supported 'ret' values and their respective SW_EXITINFO2 encodings: 7448 7449 ====== ============================================================= 7450 0 0x0, i.e. success. KVM will emit an SNP_GUEST_REQUEST command 7451 to SNP firmware. 7452 ENOSPC 0x0000000100000000, i.e. not enough guest pages to hold the 7453 certificate table and certificate data. KVM will also set the 7454 RBX field in the GHBC to 'npages'. 7455 EAGAIN 0x0000000200000000, i.e. the host is busy and the guest should 7456 retry the request. 7457 EIO 0xffffffff00000000, for all other errors (this return code is 7458 a KVM-defined hypervisor value, as allowed by the GHCB) 7459 ====== ============================================================= 7460 7461 7462.. _cap_enable: 7463 74646. Capabilities that can be enabled on vCPUs 7465============================================ 7466 7467There are certain capabilities that change the behavior of the virtual CPU or 7468the virtual machine when enabled. To enable them, please see 7469:ref:`KVM_ENABLE_CAP`. 7470 7471Below you can find a list of capabilities and what their effect on the vCPU or 7472the virtual machine is when enabling them. 7473 7474The following information is provided along with the description: 7475 7476 Architectures: 7477 which instruction set architectures provide this ioctl. 7478 x86 includes both i386 and x86_64. 7479 7480 Target: 7481 whether this is a per-vcpu or per-vm capability. 7482 7483 Parameters: 7484 what parameters are accepted by the capability. 7485 7486 Returns: 7487 the return value. General error numbers (EBADF, ENOMEM, EINVAL) 7488 are not detailed, but errors with specific meanings are. 7489 7490 74916.1 KVM_CAP_PPC_OSI 7492------------------- 7493 7494:Architectures: ppc 7495:Target: vcpu 7496:Parameters: none 7497:Returns: 0 on success; -1 on error 7498 7499This capability enables interception of OSI hypercalls that otherwise would 7500be treated as normal system calls to be injected into the guest. OSI hypercalls 7501were invented by Mac-on-Linux to have a standardized communication mechanism 7502between the guest and the host. 7503 7504When this capability is enabled, KVM_EXIT_OSI can occur. 7505 7506 75076.2 KVM_CAP_PPC_PAPR 7508-------------------- 7509 7510:Architectures: ppc 7511:Target: vcpu 7512:Parameters: none 7513:Returns: 0 on success; -1 on error 7514 7515This capability enables interception of PAPR hypercalls. PAPR hypercalls are 7516done using the hypercall instruction "sc 1". 7517 7518It also sets the guest privilege level to "supervisor" mode. Usually the guest 7519runs in "hypervisor" privilege mode with a few missing features. 7520 7521In addition to the above, it changes the semantics of SDR1. In this mode, the 7522HTAB address part of SDR1 contains an HVA instead of a GPA, as PAPR keeps the 7523HTAB invisible to the guest. 7524 7525When this capability is enabled, KVM_EXIT_PAPR_HCALL can occur. 7526 7527 75286.3 KVM_CAP_SW_TLB 7529------------------ 7530 7531:Architectures: ppc 7532:Target: vcpu 7533:Parameters: args[0] is the address of a struct kvm_config_tlb 7534:Returns: 0 on success; -1 on error 7535 7536:: 7537 7538 struct kvm_config_tlb { 7539 __u64 params; 7540 __u64 array; 7541 __u32 mmu_type; 7542 __u32 array_len; 7543 }; 7544 7545Configures the virtual CPU's TLB array, establishing a shared memory area 7546between userspace and KVM. The "params" and "array" fields are userspace 7547addresses of mmu-type-specific data structures. The "array_len" field is an 7548safety mechanism, and should be set to the size in bytes of the memory that 7549userspace has reserved for the array. It must be at least the size dictated 7550by "mmu_type" and "params". 7551 7552While KVM_RUN is active, the shared region is under control of KVM. Its 7553contents are undefined, and any modification by userspace results in 7554boundedly undefined behavior. 7555 7556On return from KVM_RUN, the shared region will reflect the current state of 7557the guest's TLB. If userspace makes any changes, it must call KVM_DIRTY_TLB 7558to tell KVM which entries have been changed, prior to calling KVM_RUN again 7559on this vcpu. 7560 7561For mmu types KVM_MMU_FSL_BOOKE_NOHV and KVM_MMU_FSL_BOOKE_HV: 7562 7563 - The "params" field is of type "struct kvm_book3e_206_tlb_params". 7564 - The "array" field points to an array of type "struct 7565 kvm_book3e_206_tlb_entry". 7566 - The array consists of all entries in the first TLB, followed by all 7567 entries in the second TLB. 7568 - Within a TLB, entries are ordered first by increasing set number. Within a 7569 set, entries are ordered by way (increasing ESEL). 7570 - The hash for determining set number in TLB0 is: (MAS2 >> 12) & (num_sets - 1) 7571 where "num_sets" is the tlb_sizes[] value divided by the tlb_ways[] value. 7572 - The tsize field of mas1 shall be set to 4K on TLB0, even though the 7573 hardware ignores this value for TLB0. 7574 75756.4 KVM_CAP_S390_CSS_SUPPORT 7576---------------------------- 7577 7578:Architectures: s390 7579:Target: vcpu 7580:Parameters: none 7581:Returns: 0 on success; -1 on error 7582 7583This capability enables support for handling of channel I/O instructions. 7584 7585TEST PENDING INTERRUPTION and the interrupt portion of TEST SUBCHANNEL are 7586handled in-kernel, while the other I/O instructions are passed to userspace. 7587 7588When this capability is enabled, KVM_EXIT_S390_TSCH will occur on TEST 7589SUBCHANNEL intercepts. 7590 7591Note that even though this capability is enabled per-vcpu, the complete 7592virtual machine is affected. 7593 75946.5 KVM_CAP_PPC_EPR 7595------------------- 7596 7597:Architectures: ppc 7598:Target: vcpu 7599:Parameters: args[0] defines whether the proxy facility is active 7600:Returns: 0 on success; -1 on error 7601 7602This capability enables or disables the delivery of interrupts through the 7603external proxy facility. 7604 7605When enabled (args[0] != 0), every time the guest gets an external interrupt 7606delivered, it automatically exits into user space with a KVM_EXIT_EPR exit 7607to receive the topmost interrupt vector. 7608 7609When disabled (args[0] == 0), behavior is as if this facility is unsupported. 7610 7611When this capability is enabled, KVM_EXIT_EPR can occur. 7612 76136.6 KVM_CAP_IRQ_MPIC 7614-------------------- 7615 7616:Architectures: ppc 7617:Parameters: args[0] is the MPIC device fd; 7618 args[1] is the MPIC CPU number for this vcpu 7619 7620This capability connects the vcpu to an in-kernel MPIC device. 7621 76226.7 KVM_CAP_IRQ_XICS 7623-------------------- 7624 7625:Architectures: ppc 7626:Target: vcpu 7627:Parameters: args[0] is the XICS device fd; 7628 args[1] is the XICS CPU number (server ID) for this vcpu 7629 7630This capability connects the vcpu to an in-kernel XICS device. 7631 76326.8 KVM_CAP_S390_IRQCHIP 7633------------------------ 7634 7635:Architectures: s390 7636:Target: vm 7637:Parameters: none 7638 7639This capability enables the in-kernel irqchip for s390. Please refer to 7640"4.24 KVM_CREATE_IRQCHIP" for details. 7641 76426.9 KVM_CAP_MIPS_FPU 7643-------------------- 7644 7645:Architectures: mips 7646:Target: vcpu 7647:Parameters: args[0] is reserved for future use (should be 0). 7648 7649This capability allows the use of the host Floating Point Unit by the guest. It 7650allows the Config1.FP bit to be set to enable the FPU in the guest. Once this is 7651done the ``KVM_REG_MIPS_FPR_*`` and ``KVM_REG_MIPS_FCR_*`` registers can be 7652accessed (depending on the current guest FPU register mode), and the Status.FR, 7653Config5.FRE bits are accessible via the KVM API and also from the guest, 7654depending on them being supported by the FPU. 7655 76566.10 KVM_CAP_MIPS_MSA 7657--------------------- 7658 7659:Architectures: mips 7660:Target: vcpu 7661:Parameters: args[0] is reserved for future use (should be 0). 7662 7663This capability allows the use of the MIPS SIMD Architecture (MSA) by the guest. 7664It allows the Config3.MSAP bit to be set to enable the use of MSA by the guest. 7665Once this is done the ``KVM_REG_MIPS_VEC_*`` and ``KVM_REG_MIPS_MSA_*`` 7666registers can be accessed, and the Config5.MSAEn bit is accessible via the 7667KVM API and also from the guest. 7668 76696.74 KVM_CAP_SYNC_REGS 7670---------------------- 7671 7672:Architectures: s390, x86 7673:Target: s390: always enabled, x86: vcpu 7674:Parameters: none 7675:Returns: x86: KVM_CHECK_EXTENSION returns a bit-array indicating which register 7676 sets are supported 7677 (bitfields defined in arch/x86/include/uapi/asm/kvm.h). 7678 7679As described above in the kvm_sync_regs struct info in section :ref:`kvm_run`, 7680KVM_CAP_SYNC_REGS "allow[s] userspace to access certain guest registers 7681without having to call SET/GET_*REGS". This reduces overhead by eliminating 7682repeated ioctl calls for setting and/or getting register values. This is 7683particularly important when userspace is making synchronous guest state 7684modifications, e.g. when emulating and/or intercepting instructions in 7685userspace. 7686 7687For s390 specifics, please refer to the source code. 7688 7689For x86: 7690 7691- the register sets to be copied out to kvm_run are selectable 7692 by userspace (rather that all sets being copied out for every exit). 7693- vcpu_events are available in addition to regs and sregs. 7694 7695For x86, the 'kvm_valid_regs' field of struct kvm_run is overloaded to 7696function as an input bit-array field set by userspace to indicate the 7697specific register sets to be copied out on the next exit. 7698 7699To indicate when userspace has modified values that should be copied into 7700the vCPU, the all architecture bitarray field, 'kvm_dirty_regs' must be set. 7701This is done using the same bitflags as for the 'kvm_valid_regs' field. 7702If the dirty bit is not set, then the register set values will not be copied 7703into the vCPU even if they've been modified. 7704 7705Unused bitfields in the bitarrays must be set to zero. 7706 7707:: 7708 7709 struct kvm_sync_regs { 7710 struct kvm_regs regs; 7711 struct kvm_sregs sregs; 7712 struct kvm_vcpu_events events; 7713 }; 7714 77156.75 KVM_CAP_PPC_IRQ_XIVE 7716------------------------- 7717 7718:Architectures: ppc 7719:Target: vcpu 7720:Parameters: args[0] is the XIVE device fd; 7721 args[1] is the XIVE CPU number (server ID) for this vcpu 7722 7723This capability connects the vcpu to an in-kernel XIVE device. 7724 77256.76 KVM_CAP_HYPERV_SYNIC 7726------------------------- 7727 7728:Architectures: x86 7729:Target: vcpu 7730 7731This capability, if KVM_CHECK_EXTENSION indicates that it is 7732available, means that the kernel has an implementation of the 7733Hyper-V Synthetic interrupt controller(SynIC). Hyper-V SynIC is 7734used to support Windows Hyper-V based guest paravirt drivers(VMBus). 7735 7736In order to use SynIC, it has to be activated by setting this 7737capability via KVM_ENABLE_CAP ioctl on the vcpu fd. Note that this 7738will disable the use of APIC hardware virtualization even if supported 7739by the CPU, as it's incompatible with SynIC auto-EOI behavior. 7740 77416.77 KVM_CAP_HYPERV_SYNIC2 7742-------------------------- 7743 7744:Architectures: x86 7745:Target: vcpu 7746 7747This capability enables a newer version of Hyper-V Synthetic interrupt 7748controller (SynIC). The only difference with KVM_CAP_HYPERV_SYNIC is that KVM 7749doesn't clear SynIC message and event flags pages when they are enabled by 7750writing to the respective MSRs. 7751 77526.78 KVM_CAP_HYPERV_DIRECT_TLBFLUSH 7753----------------------------------- 7754 7755:Architectures: x86 7756:Target: vcpu 7757 7758This capability indicates that KVM running on top of Hyper-V hypervisor 7759enables Direct TLB flush for its guests meaning that TLB flush 7760hypercalls are handled by Level 0 hypervisor (Hyper-V) bypassing KVM. 7761Due to the different ABI for hypercall parameters between Hyper-V and 7762KVM, enabling this capability effectively disables all hypercall 7763handling by KVM (as some KVM hypercall may be mistakenly treated as TLB 7764flush hypercalls by Hyper-V) so userspace should disable KVM identification 7765in CPUID and only exposes Hyper-V identification. In this case, guest 7766thinks it's running on Hyper-V and only use Hyper-V hypercalls. 7767 77686.79 KVM_CAP_HYPERV_ENFORCE_CPUID 7769--------------------------------- 7770 7771:Architectures: x86 7772:Target: vcpu 7773 7774When enabled, KVM will disable emulated Hyper-V features provided to the 7775guest according to the bits Hyper-V CPUID feature leaves. Otherwise, all 7776currently implemented Hyper-V features are provided unconditionally when 7777Hyper-V identification is set in the HYPERV_CPUID_INTERFACE (0x40000001) 7778leaf. 7779 77806.80 KVM_CAP_ENFORCE_PV_FEATURE_CPUID 7781------------------------------------- 7782 7783:Architectures: x86 7784:Target: vcpu 7785 7786When enabled, KVM will disable paravirtual features provided to the 7787guest according to the bits in the KVM_CPUID_FEATURES CPUID leaf 7788(0x40000001). Otherwise, a guest may use the paravirtual features 7789regardless of what has actually been exposed through the CPUID leaf. 7790 7791.. _KVM_CAP_DIRTY_LOG_RING: 7792 7793 7794.. _cap_enable_vm: 7795 77967. Capabilities that can be enabled on VMs 7797========================================== 7798 7799There are certain capabilities that change the behavior of the virtual 7800machine when enabled. To enable them, please see section 7801:ref:`KVM_ENABLE_CAP`. Below you can find a list of capabilities and 7802what their effect on the VM is when enabling them. 7803 7804The following information is provided along with the description: 7805 7806 Architectures: 7807 which instruction set architectures provide this ioctl. 7808 x86 includes both i386 and x86_64. 7809 7810 Parameters: 7811 what parameters are accepted by the capability. 7812 7813 Returns: 7814 the return value. General error numbers (EBADF, ENOMEM, EINVAL) 7815 are not detailed, but errors with specific meanings are. 7816 7817 78187.1 KVM_CAP_PPC_ENABLE_HCALL 7819---------------------------- 7820 7821:Architectures: ppc 7822:Parameters: args[0] is the sPAPR hcall number; 7823 args[1] is 0 to disable, 1 to enable in-kernel handling 7824 7825This capability controls whether individual sPAPR hypercalls (hcalls) 7826get handled by the kernel or not. Enabling or disabling in-kernel 7827handling of an hcall is effective across the VM. On creation, an 7828initial set of hcalls are enabled for in-kernel handling, which 7829consists of those hcalls for which in-kernel handlers were implemented 7830before this capability was implemented. If disabled, the kernel will 7831not to attempt to handle the hcall, but will always exit to userspace 7832to handle it. Note that it may not make sense to enable some and 7833disable others of a group of related hcalls, but KVM does not prevent 7834userspace from doing that. 7835 7836If the hcall number specified is not one that has an in-kernel 7837implementation, the KVM_ENABLE_CAP ioctl will fail with an EINVAL 7838error. 7839 78407.2 KVM_CAP_S390_USER_SIGP 7841-------------------------- 7842 7843:Architectures: s390 7844:Parameters: none 7845 7846This capability controls which SIGP orders will be handled completely in user 7847space. With this capability enabled, all fast orders will be handled completely 7848in the kernel: 7849 7850- SENSE 7851- SENSE RUNNING 7852- EXTERNAL CALL 7853- EMERGENCY SIGNAL 7854- CONDITIONAL EMERGENCY SIGNAL 7855 7856All other orders will be handled completely in user space. 7857 7858Only privileged operation exceptions will be checked for in the kernel (or even 7859in the hardware prior to interception). If this capability is not enabled, the 7860old way of handling SIGP orders is used (partially in kernel and user space). 7861 78627.3 KVM_CAP_S390_VECTOR_REGISTERS 7863--------------------------------- 7864 7865:Architectures: s390 7866:Parameters: none 7867:Returns: 0 on success, negative value on error 7868 7869Allows use of the vector registers introduced with z13 processor, and 7870provides for the synchronization between host and user space. Will 7871return -EINVAL if the machine does not support vectors. 7872 78737.4 KVM_CAP_S390_USER_STSI 7874-------------------------- 7875 7876:Architectures: s390 7877:Parameters: none 7878 7879This capability allows post-handlers for the STSI instruction. After 7880initial handling in the kernel, KVM exits to user space with 7881KVM_EXIT_S390_STSI to allow user space to insert further data. 7882 7883Before exiting to userspace, kvm handlers should fill in s390_stsi field of 7884vcpu->run:: 7885 7886 struct { 7887 __u64 addr; 7888 __u8 ar; 7889 __u8 reserved; 7890 __u8 fc; 7891 __u8 sel1; 7892 __u16 sel2; 7893 } s390_stsi; 7894 7895 @addr - guest address of STSI SYSIB 7896 @fc - function code 7897 @sel1 - selector 1 7898 @sel2 - selector 2 7899 @ar - access register number 7900 7901KVM handlers should exit to userspace with rc = -EREMOTE. 7902 79037.5 KVM_CAP_SPLIT_IRQCHIP 7904------------------------- 7905 7906:Architectures: x86 7907:Parameters: args[0] - number of routes reserved for userspace IOAPICs 7908:Returns: 0 on success, -1 on error 7909 7910Create a local apic for each processor in the kernel. This can be used 7911instead of KVM_CREATE_IRQCHIP if the userspace VMM wishes to emulate the 7912IOAPIC and PIC (and also the PIT, even though this has to be enabled 7913separately). 7914 7915This capability also enables in kernel routing of interrupt requests; 7916when KVM_CAP_SPLIT_IRQCHIP only routes of KVM_IRQ_ROUTING_MSI type are 7917used in the IRQ routing table. The first args[0] MSI routes are reserved 7918for the IOAPIC pins. Whenever the LAPIC receives an EOI for these routes, 7919a KVM_EXIT_IOAPIC_EOI vmexit will be reported to userspace. 7920 7921Fails if VCPU has already been created, or if the irqchip is already in the 7922kernel (i.e. KVM_CREATE_IRQCHIP has already been called). 7923 79247.6 KVM_CAP_S390_RI 7925------------------- 7926 7927:Architectures: s390 7928:Parameters: none 7929 7930Allows use of runtime-instrumentation introduced with zEC12 processor. 7931Will return -EINVAL if the machine does not support runtime-instrumentation. 7932Will return -EBUSY if a VCPU has already been created. 7933 79347.7 KVM_CAP_X2APIC_API 7935---------------------- 7936 7937:Architectures: x86 7938:Parameters: args[0] - features that should be enabled 7939:Returns: 0 on success, -EINVAL when args[0] contains invalid features 7940 7941Valid feature flags in args[0] are:: 7942 7943 #define KVM_X2APIC_API_USE_32BIT_IDS (1ULL << 0) 7944 #define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1) 7945 #define KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST (1ULL << 2) 7946 #define KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST (1ULL << 3) 7947 7948Enabling KVM_X2APIC_API_USE_32BIT_IDS changes the behavior of 7949KVM_SET_GSI_ROUTING, KVM_SIGNAL_MSI, KVM_SET_LAPIC, and KVM_GET_LAPIC, 7950allowing the use of 32-bit APIC IDs. See KVM_CAP_X2APIC_API in their 7951respective sections. 7952 7953KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK must be enabled for x2APIC to work 7954in logical mode or with more than 255 VCPUs. Otherwise, KVM treats 0xff 7955as a broadcast even in x2APIC mode in order to support physical x2APIC 7956without interrupt remapping. This is undesirable in logical mode, 7957where 0xff represents CPUs 0-7 in cluster 0. 7958 7959Setting KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST instructs KVM to enable 7960Suppress EOI Broadcasts. KVM will advertise support for Suppress EOI 7961Broadcast to the guest and suppress LAPIC EOI broadcasts when the guest 7962sets the Suppress EOI Broadcast bit in the SPIV register. This flag is 7963supported only when using a split IRQCHIP. 7964 7965Setting KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST disables support for 7966Suppress EOI Broadcasts entirely, i.e. instructs KVM to NOT advertise 7967support to the guest. 7968 7969Modern VMMs should either enable KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST 7970or KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST. If not, legacy quirky 7971behavior will be used by KVM: in split IRQCHIP mode, KVM will advertise 7972support for Suppress EOI Broadcasts but not actually suppress EOI 7973broadcasts; for in-kernel IRQCHIP mode, KVM will not advertise support for 7974Suppress EOI Broadcasts. 7975 7976Setting both KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST and 7977KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST will fail with an EINVAL error, 7978as will setting KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST without a split 7979IRCHIP. 7980 79817.8 KVM_CAP_S390_USER_INSTR0 7982---------------------------- 7983 7984:Architectures: s390 7985:Parameters: none 7986 7987With this capability enabled, the illegal instruction 0x0000 (2 bytes) will 7988be intercepted and forwarded to user space. User space can use this 7989mechanism e.g. to realize 2-byte software breakpoints. The kernel will 7990not inject an operating exception for these instructions, user space has 7991to take care of that. 7992 7993This capability can be enabled dynamically even if VCPUs were already 7994created and are running. 7995 79967.9 KVM_CAP_S390_GS 7997------------------- 7998 7999:Architectures: s390 8000:Parameters: none 8001:Returns: 0 on success; -EINVAL if the machine does not support 8002 guarded storage; -EBUSY if a VCPU has already been created. 8003 8004Allows use of guarded storage for the KVM guest. 8005 80067.10 KVM_CAP_S390_AIS 8007--------------------- 8008 8009:Architectures: s390 8010:Parameters: none 8011 8012Allow use of adapter-interruption suppression. 8013:Returns: 0 on success; -EBUSY if a VCPU has already been created. 8014 80157.11 KVM_CAP_PPC_SMT 8016-------------------- 8017 8018:Architectures: ppc 8019:Parameters: vsmt_mode, flags 8020 8021Enabling this capability on a VM provides userspace with a way to set 8022the desired virtual SMT mode (i.e. the number of virtual CPUs per 8023virtual core). The virtual SMT mode, vsmt_mode, must be a power of 2 8024between 1 and 8. On POWER8, vsmt_mode must also be no greater than 8025the number of threads per subcore for the host. Currently flags must 8026be 0. A successful call to enable this capability will result in 8027vsmt_mode being returned when the KVM_CAP_PPC_SMT capability is 8028subsequently queried for the VM. This capability is only supported by 8029HV KVM, and can only be set before any VCPUs have been created. 8030The KVM_CAP_PPC_SMT_POSSIBLE capability indicates which virtual SMT 8031modes are available. 8032 80337.12 KVM_CAP_PPC_FWNMI 8034---------------------- 8035 8036:Architectures: ppc 8037:Parameters: none 8038 8039With this capability a machine check exception in the guest address 8040space will cause KVM to exit the guest with NMI exit reason. This 8041enables QEMU to build error log and branch to guest kernel registered 8042machine check handling routine. Without this capability KVM will 8043branch to guests' 0x200 interrupt vector. 8044 80457.13 KVM_CAP_X86_DISABLE_EXITS 8046------------------------------ 8047 8048:Architectures: x86 8049:Parameters: args[0] defines which exits are disabled 8050:Returns: 0 on success, -EINVAL when args[0] contains invalid exits 8051 or if any vCPUs have already been created 8052 8053Valid bits in args[0] are:: 8054 8055 #define KVM_X86_DISABLE_EXITS_MWAIT (1 << 0) 8056 #define KVM_X86_DISABLE_EXITS_HLT (1 << 1) 8057 #define KVM_X86_DISABLE_EXITS_PAUSE (1 << 2) 8058 #define KVM_X86_DISABLE_EXITS_CSTATE (1 << 3) 8059 #define KVM_X86_DISABLE_EXITS_APERFMPERF (1 << 4) 8060 8061Enabling this capability on a VM provides userspace with a way to no 8062longer intercept some instructions for improved latency in some 8063workloads, and is suggested when vCPUs are associated to dedicated 8064physical CPUs. More bits can be added in the future; userspace can 8065just pass the KVM_CHECK_EXTENSION result to KVM_ENABLE_CAP to disable 8066all such vmexits. 8067 8068Do not enable KVM_FEATURE_PV_UNHALT if you disable HLT exits. 8069 8070Virtualizing the ``IA32_APERF`` and ``IA32_MPERF`` MSRs requires more 8071than just disabling APERF/MPERF exits. While both Intel and AMD 8072document strict usage conditions for these MSRs--emphasizing that only 8073the ratio of their deltas over a time interval (T0 to T1) is 8074architecturally defined--simply passing through the MSRs can still 8075produce an incorrect ratio. 8076 8077This erroneous ratio can occur if, between T0 and T1: 8078 80791. The vCPU thread migrates between logical processors. 80802. Live migration or suspend/resume operations take place. 80813. Another task shares the vCPU's logical processor. 80824. C-states lower than C0 are emulated (e.g., via HLT interception). 80835. The guest TSC frequency doesn't match the host TSC frequency. 8084 8085Due to these complexities, KVM does not automatically associate this 8086passthrough capability with the guest CPUID bit, 8087``CPUID.6:ECX.APERFMPERF[bit 0]``. Userspace VMMs that deem this 8088mechanism adequate for virtualizing the ``IA32_APERF`` and 8089``IA32_MPERF`` MSRs must set the guest CPUID bit explicitly. 8090 8091 80927.14 KVM_CAP_S390_HPAGE_1M 8093-------------------------- 8094 8095:Architectures: s390 8096:Parameters: none 8097:Returns: 0 on success, -EINVAL if hpage module parameter was not set 8098 or cmma is enabled, or the VM has the KVM_VM_S390_UCONTROL 8099 flag set 8100 8101With this capability the KVM support for memory backing with 1m pages 8102through hugetlbfs can be enabled for a VM. After the capability is 8103enabled, cmma can't be enabled anymore and pfmfi and the storage key 8104interpretation are disabled. If cmma has already been enabled or the 8105hpage module parameter is not set to 1, -EINVAL is returned. 8106 8107While it is generally possible to create a huge page backed VM without 8108this capability, the VM will not be able to run. 8109 81107.15 KVM_CAP_MSR_PLATFORM_INFO 8111------------------------------ 8112 8113:Architectures: x86 8114:Parameters: args[0] whether feature should be enabled or not 8115 8116With this capability, a guest may read the MSR_PLATFORM_INFO MSR. Otherwise, 8117a #GP would be raised when the guest tries to access. Currently, this 8118capability does not enable write permissions of this MSR for the guest. 8119 81207.16 KVM_CAP_PPC_NESTED_HV 8121-------------------------- 8122 8123:Architectures: ppc 8124:Parameters: none 8125:Returns: 0 on success, -EINVAL when the implementation doesn't support 8126 nested-HV virtualization. 8127 8128HV-KVM on POWER9 and later systems allows for "nested-HV" 8129virtualization, which provides a way for a guest VM to run guests that 8130can run using the CPU's supervisor mode (privileged non-hypervisor 8131state). Enabling this capability on a VM depends on the CPU having 8132the necessary functionality and on the facility being enabled with a 8133kvm-hv module parameter. 8134 81357.17 KVM_CAP_EXCEPTION_PAYLOAD 8136------------------------------ 8137 8138:Architectures: x86 8139:Parameters: args[0] whether feature should be enabled or not 8140 8141With this capability enabled, CR2 will not be modified prior to the 8142emulated VM-exit when L1 intercepts a #PF exception that occurs in 8143L2. Similarly, for kvm-intel only, DR6 will not be modified prior to 8144the emulated VM-exit when L1 intercepts a #DB exception that occurs in 8145L2. As a result, when KVM_GET_VCPU_EVENTS reports a pending #PF (or 8146#DB) exception for L2, exception.has_payload will be set and the 8147faulting address (or the new DR6 bits*) will be reported in the 8148exception_payload field. Similarly, when userspace injects a #PF (or 8149#DB) into L2 using KVM_SET_VCPU_EVENTS, it is expected to set 8150exception.has_payload and to put the faulting address - or the new DR6 8151bits\ [#]_ - in the exception_payload field. 8152 8153This capability also enables exception.pending in struct 8154kvm_vcpu_events, which allows userspace to distinguish between pending 8155and injected exceptions. 8156 8157 8158.. [#] For the new DR6 bits, note that bit 16 is set iff the #DB exception 8159 will clear DR6.RTM. 8160 81617.18 KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 8162-------------------------------------- 8163 8164:Architectures: x86, arm64, mips 8165:Parameters: args[0] whether feature should be enabled or not 8166 8167Valid flags are:: 8168 8169 #define KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE (1 << 0) 8170 #define KVM_DIRTY_LOG_INITIALLY_SET (1 << 1) 8171 8172With KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE is set, KVM_GET_DIRTY_LOG will not 8173automatically clear and write-protect all pages that are returned as dirty. 8174Rather, userspace will have to do this operation separately using 8175KVM_CLEAR_DIRTY_LOG. 8176 8177At the cost of a slightly more complicated operation, this provides better 8178scalability and responsiveness for two reasons. First, 8179KVM_CLEAR_DIRTY_LOG ioctl can operate on a 64-page granularity rather 8180than requiring to sync a full memslot; this ensures that KVM does not 8181take spinlocks for an extended period of time. Second, in some cases a 8182large amount of time can pass between a call to KVM_GET_DIRTY_LOG and 8183userspace actually using the data in the page. Pages can be modified 8184during this time, which is inefficient for both the guest and userspace: 8185the guest will incur a higher penalty due to write protection faults, 8186while userspace can see false reports of dirty pages. Manual reprotection 8187helps reducing this time, improving guest performance and reducing the 8188number of dirty log false positives. 8189 8190With KVM_DIRTY_LOG_INITIALLY_SET set, all the bits of the dirty bitmap 8191will be initialized to 1 when created. This also improves performance because 8192dirty logging can be enabled gradually in small chunks on the first call 8193to KVM_CLEAR_DIRTY_LOG. KVM_DIRTY_LOG_INITIALLY_SET depends on 8194KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE (it is also only available on 8195x86, arm64 and riscv for now). 8196 8197KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 was previously available under the name 8198KVM_CAP_MANUAL_DIRTY_LOG_PROTECT, but the implementation had bugs that make 8199it hard or impossible to use it correctly. The availability of 8200KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 signals that those bugs are fixed. 8201Userspace should not try to use KVM_CAP_MANUAL_DIRTY_LOG_PROTECT. 8202 82037.19 KVM_CAP_PPC_SECURE_GUEST 8204------------------------------ 8205 8206:Architectures: ppc 8207 8208This capability indicates that KVM is running on a host that has 8209ultravisor firmware and thus can support a secure guest. On such a 8210system, a guest can ask the ultravisor to make it a secure guest, 8211one whose memory is inaccessible to the host except for pages which 8212are explicitly requested to be shared with the host. The ultravisor 8213notifies KVM when a guest requests to become a secure guest, and KVM 8214has the opportunity to veto the transition. 8215 8216If present, this capability can be enabled for a VM, meaning that KVM 8217will allow the transition to secure guest mode. Otherwise KVM will 8218veto the transition. 8219 82207.20 KVM_CAP_HALT_POLL 8221---------------------- 8222 8223:Architectures: all 8224:Target: VM 8225:Parameters: args[0] is the maximum poll time in nanoseconds 8226:Returns: 0 on success; -1 on error 8227 8228KVM_CAP_HALT_POLL overrides the kvm.halt_poll_ns module parameter to set the 8229maximum halt-polling time for all vCPUs in the target VM. This capability can 8230be invoked at any time and any number of times to dynamically change the 8231maximum halt-polling time. 8232 8233See Documentation/virt/kvm/halt-polling.rst for more information on halt 8234polling. 8235 82367.21 KVM_CAP_X86_USER_SPACE_MSR 8237------------------------------- 8238 8239:Architectures: x86 8240:Target: VM 8241:Parameters: args[0] contains the mask of KVM_MSR_EXIT_REASON_* events to report 8242:Returns: 0 on success; -1 on error 8243 8244This capability allows userspace to intercept RDMSR and WRMSR instructions if 8245access to an MSR is denied. By default, KVM injects #GP on denied accesses. 8246 8247When a guest requests to read or write an MSR, KVM may not implement all MSRs 8248that are relevant to a respective system. It also does not differentiate by 8249CPU type. 8250 8251To allow more fine grained control over MSR handling, userspace may enable 8252this capability. With it enabled, MSR accesses that match the mask specified in 8253args[0] and would trigger a #GP inside the guest will instead trigger 8254KVM_EXIT_X86_RDMSR and KVM_EXIT_X86_WRMSR exit notifications. Userspace 8255can then implement model specific MSR handling and/or user notifications 8256to inform a user that an MSR was not emulated/virtualized by KVM. 8257 8258The valid mask flags are: 8259 8260============================ =============================================== 8261 KVM_MSR_EXIT_REASON_UNKNOWN intercept accesses to unknown (to KVM) MSRs 8262 KVM_MSR_EXIT_REASON_INVAL intercept accesses that are architecturally 8263 invalid according to the vCPU model and/or mode 8264 KVM_MSR_EXIT_REASON_FILTER intercept accesses that are denied by userspace 8265 via KVM_X86_SET_MSR_FILTER 8266============================ =============================================== 8267 82687.22 KVM_CAP_X86_BUS_LOCK_EXIT 8269------------------------------- 8270 8271:Architectures: x86 8272:Target: VM 8273:Parameters: args[0] defines the policy used when bus locks detected in guest 8274:Returns: 0 on success, -EINVAL when args[0] contains invalid bits 8275 8276Valid bits in args[0] are:: 8277 8278 #define KVM_BUS_LOCK_DETECTION_OFF (1 << 0) 8279 #define KVM_BUS_LOCK_DETECTION_EXIT (1 << 1) 8280 8281Enabling this capability on a VM provides userspace with a way to select a 8282policy to handle the bus locks detected in guest. Userspace can obtain the 8283supported modes from the result of KVM_CHECK_EXTENSION and define it through 8284the KVM_ENABLE_CAP. The supported modes are mutually-exclusive. 8285 8286This capability allows userspace to force VM exits on bus locks detected in the 8287guest, irrespective whether or not the host has enabled split-lock detection 8288(which triggers an #AC exception that KVM intercepts). This capability is 8289intended to mitigate attacks where a malicious/buggy guest can exploit bus 8290locks to degrade the performance of the whole system. 8291 8292If KVM_BUS_LOCK_DETECTION_OFF is set, KVM doesn't force guest bus locks to VM 8293exit, although the host kernel's split-lock #AC detection still applies, if 8294enabled. 8295 8296If KVM_BUS_LOCK_DETECTION_EXIT is set, KVM enables a CPU feature that ensures 8297bus locks in the guest trigger a VM exit, and KVM exits to userspace for all 8298such VM exits, e.g. to allow userspace to throttle the offending guest and/or 8299apply some other policy-based mitigation. When exiting to userspace, KVM sets 8300KVM_RUN_X86_BUS_LOCK in vcpu-run->flags, and conditionally sets the exit_reason 8301to KVM_EXIT_X86_BUS_LOCK. 8302 8303Due to differences in the underlying hardware implementation, the vCPU's RIP at 8304the time of exit diverges between Intel and AMD. On Intel hosts, RIP points at 8305the next instruction, i.e. the exit is trap-like. On AMD hosts, RIP points at 8306the offending instruction, i.e. the exit is fault-like. 8307 8308Note! Detected bus locks may be coincident with other exits to userspace, i.e. 8309KVM_RUN_X86_BUS_LOCK should be checked regardless of the primary exit reason if 8310userspace wants to take action on all detected bus locks. 8311 83127.23 KVM_CAP_PPC_DAWR1 8313---------------------- 8314 8315:Architectures: ppc 8316:Parameters: none 8317:Returns: 0 on success, -EINVAL when CPU doesn't support 2nd DAWR 8318 8319This capability can be used to check / enable 2nd DAWR feature provided 8320by POWER10 processor. 8321 8322 83237.24 KVM_CAP_VM_COPY_ENC_CONTEXT_FROM 8324------------------------------------- 8325 8326:Architectures: x86 SEV enabled 8327:Type: vm 8328:Parameters: args[0] is the fd of the source vm 8329:Returns: 0 on success; ENOTTY on error 8330 8331This capability enables userspace to copy encryption context from the vm 8332indicated by the fd to the vm this is called on. 8333 8334This is intended to support in-guest workloads scheduled by the host. This 8335allows the in-guest workload to maintain its own NPTs and keeps the two vms 8336from accidentally clobbering each other with interrupts and the like (separate 8337APIC/MSRs/etc). 8338 83397.25 KVM_CAP_SGX_ATTRIBUTE 8340-------------------------- 8341 8342:Architectures: x86 8343:Target: VM 8344:Parameters: args[0] is a file handle of a SGX attribute file in securityfs 8345:Returns: 0 on success, -EINVAL if the file handle is invalid or if a requested 8346 attribute is not supported by KVM. 8347 8348KVM_CAP_SGX_ATTRIBUTE enables a userspace VMM to grant a VM access to one or 8349more privileged enclave attributes. args[0] must hold a file handle to a valid 8350SGX attribute file corresponding to an attribute that is supported/restricted 8351by KVM (currently only PROVISIONKEY). 8352 8353The SGX subsystem restricts access to a subset of enclave attributes to provide 8354additional security for an uncompromised kernel, e.g. use of the PROVISIONKEY 8355is restricted to deter malware from using the PROVISIONKEY to obtain a stable 8356system fingerprint. To prevent userspace from circumventing such restrictions 8357by running an enclave in a VM, KVM prevents access to privileged attributes by 8358default. 8359 8360See Documentation/arch/x86/sgx.rst for more details. 8361 83627.27 KVM_CAP_EXIT_ON_EMULATION_FAILURE 8363-------------------------------------- 8364 8365:Architectures: x86 8366:Parameters: args[0] whether the feature should be enabled or not 8367 8368When this capability is enabled, an emulation failure will result in an exit 8369to userspace with KVM_INTERNAL_ERROR (except when the emulator was invoked 8370to handle a VMware backdoor instruction). Furthermore, KVM will now provide up 8371to 15 instruction bytes for any exit to userspace resulting from an emulation 8372failure. When these exits to userspace occur use the emulation_failure struct 8373instead of the internal struct. They both have the same layout, but the 8374emulation_failure struct matches the content better. It also explicitly 8375defines the 'flags' field which is used to describe the fields in the struct 8376that are valid (ie: if KVM_INTERNAL_ERROR_EMULATION_FLAG_INSTRUCTION_BYTES is 8377set in the 'flags' field then both 'insn_size' and 'insn_bytes' have valid data 8378in them.) 8379 83807.28 KVM_CAP_ARM_MTE 8381-------------------- 8382 8383:Architectures: arm64 8384:Parameters: none 8385 8386This capability indicates that KVM (and the hardware) supports exposing the 8387Memory Tagging Extensions (MTE) to the guest. It must also be enabled by the 8388VMM before creating any VCPUs to allow the guest access. Note that MTE is only 8389available to a guest running in AArch64 mode and enabling this capability will 8390cause attempts to create AArch32 VCPUs to fail. 8391 8392When enabled the guest is able to access tags associated with any memory given 8393to the guest. KVM will ensure that the tags are maintained during swap or 8394hibernation of the host; however the VMM needs to manually save/restore the 8395tags as appropriate if the VM is migrated. 8396 8397When this capability is enabled all memory in memslots must be mapped as 8398``MAP_ANONYMOUS`` or with a RAM-based file mapping (``tmpfs``, ``memfd``), 8399attempts to create a memslot with an invalid mmap will result in an 8400-EINVAL return. 8401 8402When enabled the VMM may make use of the ``KVM_ARM_MTE_COPY_TAGS`` ioctl to 8403perform a bulk copy of tags to/from the guest. 8404 84057.29 KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM 8406------------------------------------- 8407 8408:Architectures: x86 SEV enabled 8409:Type: vm 8410:Parameters: args[0] is the fd of the source vm 8411:Returns: 0 on success 8412 8413This capability enables userspace to migrate the encryption context from the VM 8414indicated by the fd to the VM this is called on. 8415 8416This is intended to support intra-host migration of VMs between userspace VMMs, 8417upgrading the VMM process without interrupting the guest. 8418 84197.31 KVM_CAP_DISABLE_QUIRKS2 8420---------------------------- 8421 8422:Parameters: args[0] - set of KVM quirks to disable 8423:Architectures: x86 8424:Type: vm 8425 8426This capability, if enabled, will cause KVM to disable some behavior 8427quirks. 8428 8429Calling KVM_CHECK_EXTENSION for this capability returns a bitmask of 8430quirks that can be disabled in KVM. 8431 8432The argument to KVM_ENABLE_CAP for this capability is a bitmask of 8433quirks to disable, and must be a subset of the bitmask returned by 8434KVM_CHECK_EXTENSION. 8435 8436The valid bits in cap.args[0] are: 8437 8438=================================== ============================================ 8439 KVM_X86_QUIRK_LINT0_REENABLED By default, the reset value for the LVT 8440 LINT0 register is 0x700 (APIC_MODE_EXTINT). 8441 When this quirk is disabled, the reset value 8442 is 0x10000 (APIC_LVT_MASKED). 8443 8444 KVM_X86_QUIRK_CD_NW_CLEARED By default, KVM clears CR0.CD and CR0.NW on 8445 AMD CPUs to workaround buggy guest firmware 8446 that runs in perpetuity with CR0.CD, i.e. 8447 with caches in "no fill" mode. 8448 8449 When this quirk is disabled, KVM does not 8450 change the value of CR0.CD and CR0.NW. 8451 8452 KVM_X86_QUIRK_LAPIC_MMIO_HOLE By default, the MMIO LAPIC interface is 8453 available even when configured for x2APIC 8454 mode. When this quirk is disabled, KVM 8455 disables the MMIO LAPIC interface if the 8456 LAPIC is in x2APIC mode. 8457 8458 KVM_X86_QUIRK_OUT_7E_INC_RIP By default, KVM pre-increments %rip before 8459 exiting to userspace for an OUT instruction 8460 to port 0x7e. When this quirk is disabled, 8461 KVM does not pre-increment %rip before 8462 exiting to userspace. 8463 8464 KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT When this quirk is disabled, KVM sets 8465 CPUID.01H:ECX[bit 3] (MONITOR/MWAIT) if 8466 IA32_MISC_ENABLE[bit 18] (MWAIT) is set. 8467 Additionally, when this quirk is disabled, 8468 KVM clears CPUID.01H:ECX[bit 3] if 8469 IA32_MISC_ENABLE[bit 18] is cleared. 8470 8471 KVM_X86_QUIRK_FIX_HYPERCALL_INSN By default, KVM rewrites guest 8472 VMMCALL/VMCALL instructions to match the 8473 vendor's hypercall instruction for the 8474 system. When this quirk is disabled, KVM 8475 will no longer rewrite invalid guest 8476 hypercall instructions. Executing the 8477 incorrect hypercall instruction will 8478 generate a #UD within the guest. 8479 8480KVM_X86_QUIRK_MWAIT_NEVER_UD_FAULTS By default, KVM emulates MONITOR/MWAIT (if 8481 they are intercepted) as NOPs regardless of 8482 whether or not MONITOR/MWAIT are supported 8483 according to guest CPUID. When this quirk 8484 is disabled and KVM_X86_DISABLE_EXITS_MWAIT 8485 is not set (MONITOR/MWAIT are intercepted), 8486 KVM will inject a #UD on MONITOR/MWAIT if 8487 they're unsupported per guest CPUID. Note, 8488 KVM will modify MONITOR/MWAIT support in 8489 guest CPUID on writes to MISC_ENABLE if 8490 KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT is 8491 disabled. 8492 8493KVM_X86_QUIRK_SLOT_ZAP_ALL By default, for KVM_X86_DEFAULT_VM VMs, KVM 8494 invalidates all SPTEs in all memslots and 8495 address spaces when a memslot is deleted or 8496 moved. When this quirk is disabled (or the 8497 VM type isn't KVM_X86_DEFAULT_VM), KVM only 8498 ensures the backing memory of the deleted 8499 or moved memslot isn't reachable, i.e KVM 8500 _may_ invalidate only SPTEs related to the 8501 memslot. 8502 8503KVM_X86_QUIRK_STUFF_FEATURE_MSRS By default, at vCPU creation, KVM sets the 8504 vCPU's MSR_IA32_PERF_CAPABILITIES (0x345), 8505 MSR_IA32_ARCH_CAPABILITIES (0x10a), 8506 MSR_PLATFORM_INFO (0xce), and all VMX MSRs 8507 (0x480..0x492) to the maximal capabilities 8508 supported by KVM. KVM also sets 8509 MSR_IA32_UCODE_REV (0x8b) to an arbitrary 8510 value (which is different for Intel vs. 8511 AMD). Lastly, when guest CPUID is set (by 8512 userspace), KVM modifies select VMX MSR 8513 fields to force consistency between guest 8514 CPUID and L2's effective ISA. When this 8515 quirk is disabled, KVM zeroes the vCPU's MSR 8516 values (with two exceptions, see below), 8517 i.e. treats the feature MSRs like CPUID 8518 leaves and gives userspace full control of 8519 the vCPU model definition. This quirk does 8520 not affect VMX MSRs CR0/CR4_FIXED1 (0x487 8521 and 0x489), as KVM does now allow them to 8522 be set by userspace (KVM sets them based on 8523 guest CPUID, for safety purposes). 8524 8525KVM_X86_QUIRK_IGNORE_GUEST_PAT By default, on Intel platforms, KVM ignores 8526 guest PAT and forces the effective memory 8527 type to WB in EPT. The quirk is not available 8528 on Intel platforms which are incapable of 8529 safely honoring guest PAT (i.e., without CPU 8530 self-snoop, KVM always ignores guest PAT and 8531 forces effective memory type to WB). It is 8532 also ignored on AMD platforms or, on Intel, 8533 when a VM has non-coherent DMA devices 8534 assigned; KVM always honors guest PAT in 8535 such case. The quirk is needed to avoid 8536 slowdowns on certain Intel Xeon platforms 8537 (e.g. ICX, SPR) where self-snoop feature is 8538 supported but UC is slow enough to cause 8539 issues with some older guests that use 8540 UC instead of WC to map the video RAM. 8541 Userspace can disable the quirk to honor 8542 guest PAT if it knows that there is no such 8543 guest software, for example if it does not 8544 expose a bochs graphics device (which is 8545 known to have had a buggy driver). 8546=================================== ============================================ 8547 85487.32 KVM_CAP_MAX_VCPU_ID 8549------------------------ 8550 8551:Architectures: x86 8552:Target: VM 8553:Parameters: args[0] - maximum APIC ID value set for current VM 8554:Returns: 0 on success, -EINVAL if args[0] is beyond KVM_MAX_VCPU_IDS 8555 supported in KVM or if it has been set. 8556 8557This capability allows userspace to specify maximum possible APIC ID 8558assigned for current VM session prior to the creation of vCPUs, saving 8559memory for data structures indexed by the APIC ID. Userspace is able 8560to calculate the limit to APIC ID values from designated 8561CPU topology. 8562 8563The value can be changed only until KVM_ENABLE_CAP is set to a nonzero 8564value or until a vCPU is created. Upon creation of the first vCPU, 8565if the value was set to zero or KVM_ENABLE_CAP was not invoked, KVM 8566uses the return value of KVM_CHECK_EXTENSION(KVM_CAP_MAX_VCPU_ID) as 8567the maximum APIC ID. 8568 85697.33 KVM_CAP_X86_NOTIFY_VMEXIT 8570------------------------------ 8571 8572:Architectures: x86 8573:Target: VM 8574:Parameters: args[0] is the value of notify window as well as some flags 8575:Returns: 0 on success, -EINVAL if args[0] contains invalid flags or notify 8576 VM exit is unsupported. 8577 8578Bits 63:32 of args[0] are used for notify window. 8579Bits 31:0 of args[0] are for some flags. Valid bits are:: 8580 8581 #define KVM_X86_NOTIFY_VMEXIT_ENABLED (1 << 0) 8582 #define KVM_X86_NOTIFY_VMEXIT_USER (1 << 1) 8583 8584This capability allows userspace to configure the notify VM exit on/off 8585in per-VM scope during VM creation. Notify VM exit is disabled by default. 8586When userspace sets KVM_X86_NOTIFY_VMEXIT_ENABLED bit in args[0], VMM will 8587enable this feature with the notify window provided, which will generate 8588a VM exit if no event window occurs in VM non-root mode for a specified of 8589time (notify window). 8590 8591If KVM_X86_NOTIFY_VMEXIT_USER is set in args[0], upon notify VM exits happen, 8592KVM would exit to userspace for handling. 8593 8594This capability is aimed to mitigate the threat that malicious VMs can 8595cause CPU stuck (due to event windows don't open up) and make the CPU 8596unavailable to host or other VMs. 8597 85987.35 KVM_CAP_X86_APIC_BUS_CYCLES_NS 8599----------------------------------- 8600 8601:Architectures: x86 8602:Target: VM 8603:Parameters: args[0] is the desired APIC bus clock rate, in nanoseconds 8604:Returns: 0 on success, -EINVAL if args[0] contains an invalid value for the 8605 frequency or if any vCPUs have been created, -ENXIO if a virtual 8606 local APIC has not been created using KVM_CREATE_IRQCHIP. 8607 8608This capability sets the VM's APIC bus clock frequency, used by KVM's in-kernel 8609virtual APIC when emulating APIC timers. KVM's default value can be retrieved 8610by KVM_CHECK_EXTENSION. 8611 8612Note: Userspace is responsible for correctly configuring CPUID 0x15, a.k.a. the 8613core crystal clock frequency, if a non-zero CPUID 0x15 is exposed to the guest. 8614 86157.36 KVM_CAP_DIRTY_LOG_RING/KVM_CAP_DIRTY_LOG_RING_ACQ_REL 8616---------------------------------------------------------- 8617 8618:Architectures: x86, arm64, riscv 8619:Type: vm 8620:Parameters: args[0] - size of the dirty log ring 8621 8622KVM is capable of tracking dirty memory using ring buffers that are 8623mmapped into userspace; there is one dirty ring per vcpu. 8624 8625The dirty ring is available to userspace as an array of 8626``struct kvm_dirty_gfn``. Each dirty entry is defined as:: 8627 8628 struct kvm_dirty_gfn { 8629 __u32 flags; 8630 __u32 slot; /* as_id | slot_id */ 8631 __u64 offset; 8632 }; 8633 8634The following values are defined for the flags field to define the 8635current state of the entry:: 8636 8637 #define KVM_DIRTY_GFN_F_DIRTY BIT(0) 8638 #define KVM_DIRTY_GFN_F_RESET BIT(1) 8639 #define KVM_DIRTY_GFN_F_MASK 0x3 8640 8641Userspace should call KVM_ENABLE_CAP ioctl right after KVM_CREATE_VM 8642ioctl to enable this capability for the new guest and set the size of 8643the rings. Enabling the capability is only allowed before creating any 8644vCPU, and the size of the ring must be a power of two. The larger the 8645ring buffer, the less likely the ring is full and the VM is forced to 8646exit to userspace. The optimal size depends on the workload, but it is 8647recommended that it be at least 64 KiB (4096 entries). 8648 8649Just like for dirty page bitmaps, the buffer tracks writes to 8650all user memory regions for which the KVM_MEM_LOG_DIRTY_PAGES flag was 8651set in KVM_SET_USER_MEMORY_REGION. Once a memory region is registered 8652with the flag set, userspace can start harvesting dirty pages from the 8653ring buffer. 8654 8655An entry in the ring buffer can be unused (flag bits ``00``), 8656dirty (flag bits ``01``) or harvested (flag bits ``1X``). The 8657state machine for the entry is as follows:: 8658 8659 dirtied harvested reset 8660 00 -----------> 01 -------------> 1X -------+ 8661 ^ | 8662 | | 8663 +------------------------------------------+ 8664 8665To harvest the dirty pages, userspace accesses the mmapped ring buffer 8666to read the dirty GFNs. If the flags has the DIRTY bit set (at this stage 8667the RESET bit must be cleared), then it means this GFN is a dirty GFN. 8668The userspace should harvest this GFN and mark the flags from state 8669``01b`` to ``1Xb`` (bit 0 will be ignored by KVM, but bit 1 must be set 8670to show that this GFN is harvested and waiting for a reset), and move 8671on to the next GFN. The userspace should continue to do this until the 8672flags of a GFN have the DIRTY bit cleared, meaning that it has harvested 8673all the dirty GFNs that were available. 8674 8675Note that on weakly ordered architectures, userspace accesses to the 8676ring buffer (and more specifically the 'flags' field) must be ordered, 8677using load-acquire/store-release accessors when available, or any 8678other memory barrier that will ensure this ordering. 8679 8680It's not necessary for userspace to harvest the all dirty GFNs at once. 8681However it must collect the dirty GFNs in sequence, i.e., the userspace 8682program cannot skip one dirty GFN to collect the one next to it. 8683 8684After processing one or more entries in the ring buffer, userspace 8685calls the VM ioctl KVM_RESET_DIRTY_RINGS to notify the kernel about 8686it, so that the kernel will reprotect those collected GFNs. 8687Therefore, the ioctl must be called *before* reading the content of 8688the dirty pages. 8689 8690The dirty ring can get full. When it happens, the KVM_RUN of the 8691vcpu will return with exit reason KVM_EXIT_DIRTY_RING_FULL. 8692 8693The dirty ring interface has a major difference comparing to the 8694KVM_GET_DIRTY_LOG interface in that, when reading the dirty ring from 8695userspace, it's still possible that the kernel has not yet flushed the 8696processor's dirty page buffers into the kernel buffer (with dirty bitmaps, the 8697flushing is done by the KVM_GET_DIRTY_LOG ioctl). To achieve that, one 8698needs to kick the vcpu out of KVM_RUN using a signal. The resulting 8699vmexit ensures that all dirty GFNs are flushed to the dirty rings. 8700 8701NOTE: KVM_CAP_DIRTY_LOG_RING_ACQ_REL is the only capability that 8702should be exposed by weakly ordered architecture, in order to indicate 8703the additional memory ordering requirements imposed on userspace when 8704reading the state of an entry and mutating it from DIRTY to HARVESTED. 8705Architecture with TSO-like ordering (such as x86) are allowed to 8706expose both KVM_CAP_DIRTY_LOG_RING and KVM_CAP_DIRTY_LOG_RING_ACQ_REL 8707to userspace. 8708 8709After enabling the dirty rings, the userspace needs to detect the 8710capability of KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP to see whether the 8711ring structures can be backed by per-slot bitmaps. With this capability 8712advertised, it means the architecture can dirty guest pages without 8713vcpu/ring context, so that some of the dirty information will still be 8714maintained in the bitmap structure. KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP 8715can't be enabled if the capability of KVM_CAP_DIRTY_LOG_RING_ACQ_REL 8716hasn't been enabled, or any memslot has been existing. 8717 8718Note that the bitmap here is only a backup of the ring structure. The 8719use of the ring and bitmap combination is only beneficial if there is 8720only a very small amount of memory that is dirtied out of vcpu/ring 8721context. Otherwise, the stand-alone per-slot bitmap mechanism needs to 8722be considered. 8723 8724To collect dirty bits in the backup bitmap, userspace can use the same 8725KVM_GET_DIRTY_LOG ioctl. KVM_CLEAR_DIRTY_LOG isn't needed as long as all 8726the generation of the dirty bits is done in a single pass. Collecting 8727the dirty bitmap should be the very last thing that the VMM does before 8728considering the state as complete. VMM needs to ensure that the dirty 8729state is final and avoid missing dirty pages from another ioctl ordered 8730after the bitmap collection. 8731 8732NOTE: Multiple examples of using the backup bitmap: (1) save vgic/its 8733tables through command KVM_DEV_ARM_{VGIC_GRP_CTRL, ITS_SAVE_TABLES} on 8734KVM device "kvm-arm-vgic-its". (2) restore vgic/its tables through 8735command KVM_DEV_ARM_{VGIC_GRP_CTRL, ITS_RESTORE_TABLES} on KVM device 8736"kvm-arm-vgic-its". VGICv3 LPI pending status is restored. (3) save 8737vgic3 pending table through KVM_DEV_ARM_VGIC_{GRP_CTRL, SAVE_PENDING_TABLES} 8738command on KVM device "kvm-arm-vgic-v3". 8739 87407.37 KVM_CAP_PMU_CAPABILITY 8741--------------------------- 8742 8743:Architectures: x86 8744:Type: vm 8745:Parameters: arg[0] is bitmask of PMU virtualization capabilities. 8746:Returns: 0 on success, -EINVAL when arg[0] contains invalid bits 8747 8748This capability alters PMU virtualization in KVM. 8749 8750Calling KVM_CHECK_EXTENSION for this capability returns a bitmask of 8751PMU virtualization capabilities that can be adjusted on a VM. 8752 8753The argument to KVM_ENABLE_CAP is also a bitmask and selects specific 8754PMU virtualization capabilities to be applied to the VM. This can 8755only be invoked on a VM prior to the creation of VCPUs. 8756 8757At this time, KVM_PMU_CAP_DISABLE is the only capability. Setting 8758this capability will disable PMU virtualization for that VM. Usermode 8759should adjust CPUID leaf 0xA to reflect that the PMU is disabled. 8760 87617.38 KVM_CAP_VM_DISABLE_NX_HUGE_PAGES 8762------------------------------------- 8763 8764:Architectures: x86 8765:Type: vm 8766:Parameters: arg[0] must be 0. 8767:Returns: 0 on success, -EPERM if the userspace process does not 8768 have CAP_SYS_BOOT, -EINVAL if args[0] is not 0 or any vCPUs have been 8769 created. 8770 8771This capability disables the NX huge pages mitigation for iTLB MULTIHIT. 8772 8773The capability has no effect if the nx_huge_pages module parameter is not set. 8774 8775This capability may only be set before any vCPUs are created. 8776 87777.39 KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE 8778--------------------------------------- 8779 8780:Architectures: arm64 8781:Type: vm 8782:Parameters: arg[0] is the new split chunk size. 8783:Returns: 0 on success, -EINVAL if any memslot was already created. 8784 8785This capability sets the chunk size used in Eager Page Splitting. 8786 8787Eager Page Splitting improves the performance of dirty-logging (used 8788in live migrations) when guest memory is backed by huge-pages. It 8789avoids splitting huge-pages (into PAGE_SIZE pages) on fault, by doing 8790it eagerly when enabling dirty logging (with the 8791KVM_MEM_LOG_DIRTY_PAGES flag for a memory region), or when using 8792KVM_CLEAR_DIRTY_LOG. 8793 8794The chunk size specifies how many pages to break at a time, using a 8795single allocation for each chunk. Bigger the chunk size, more pages 8796need to be allocated ahead of time. 8797 8798The chunk size needs to be a valid block size. The list of acceptable 8799block sizes is exposed in KVM_CAP_ARM_SUPPORTED_BLOCK_SIZES as a 880064-bit bitmap (each bit describing a block size). The default value is 88010, to disable the eager page splitting. 8802 88037.40 KVM_CAP_EXIT_HYPERCALL 8804--------------------------- 8805 8806:Architectures: x86 8807:Type: vm 8808 8809This capability, if enabled, will cause KVM to exit to userspace 8810with KVM_EXIT_HYPERCALL exit reason to process some hypercalls. 8811 8812Calling KVM_CHECK_EXTENSION for this capability will return a bitmask 8813of hypercalls that can be configured to exit to userspace. 8814Right now, the only such hypercall is KVM_HC_MAP_GPA_RANGE. 8815 8816The argument to KVM_ENABLE_CAP is also a bitmask, and must be a subset 8817of the result of KVM_CHECK_EXTENSION. KVM will forward to userspace 8818the hypercalls whose corresponding bit is in the argument, and return 8819ENOSYS for the others. 8820 88217.41 KVM_CAP_ARM_SYSTEM_SUSPEND 8822------------------------------- 8823 8824:Architectures: arm64 8825:Type: vm 8826 8827When enabled, KVM will exit to userspace with KVM_EXIT_SYSTEM_EVENT of 8828type KVM_SYSTEM_EVENT_SUSPEND to process the guest suspend request. 8829 88307.42 KVM_CAP_ARM_WRITABLE_IMP_ID_REGS 8831------------------------------------- 8832 8833:Architectures: arm64 8834:Target: VM 8835:Parameters: None 8836:Returns: 0 on success, -EINVAL if vCPUs have been created before enabling this 8837 capability. 8838 8839This capability changes the behavior of the registers that identify a PE 8840implementation of the Arm architecture: MIDR_EL1, REVIDR_EL1, and AIDR_EL1. 8841By default, these registers are visible to userspace but treated as invariant. 8842 8843When this capability is enabled, KVM allows userspace to change the 8844aforementioned registers before the first KVM_RUN. These registers are VM 8845scoped, meaning that the same set of values are presented on all vCPUs in a 8846given VM. 8847 88487.43 KVM_CAP_RISCV_MP_STATE_RESET 8849--------------------------------- 8850 8851:Architectures: riscv 8852:Type: VM 8853:Parameters: None 8854:Returns: 0 on success, -EINVAL if arg[0] is not zero 8855 8856When this capability is enabled, KVM resets the VCPU when setting 8857MP_STATE_INIT_RECEIVED through IOCTL. The original MP_STATE is preserved. 8858 88597.44 KVM_CAP_ARM_CACHEABLE_PFNMAP_SUPPORTED 8860------------------------------------------- 8861 8862:Architectures: arm64 8863:Target: VM 8864:Parameters: None 8865 8866This capability indicate to the userspace whether a PFNMAP memory region 8867can be safely mapped as cacheable. This relies on the presence of 8868force write back (FWB) feature support on the hardware. 8869 88707.45 KVM_CAP_ARM_SEA_TO_USER 8871---------------------------- 8872 8873:Architecture: arm64 8874:Target: VM 8875:Parameters: none 8876:Returns: 0 on success, -EINVAL if unsupported. 8877 8878When this capability is enabled, KVM may exit to userspace for SEAs taken to 8879EL2 resulting from a guest access. See ``KVM_EXIT_ARM_SEA`` for more 8880information. 8881 88827.46 KVM_CAP_S390_USER_OPEREXEC 8883------------------------------- 8884 8885:Architectures: s390 8886:Parameters: none 8887 8888When this capability is enabled KVM forwards all operation exceptions 8889that it doesn't handle itself to user space. This also includes the 88900x0000 instructions managed by KVM_CAP_S390_USER_INSTR0. This is 8891helpful if user space wants to emulate instructions which are not 8892(yet) implemented in hardware. 8893 8894This capability can be enabled dynamically even if VCPUs were already 8895created and are running. 8896 88978. Other capabilities. 8898====================== 8899 8900This section lists capabilities that give information about other 8901features of the KVM implementation. 8902 89038.1 KVM_CAP_PPC_HWRNG 8904--------------------- 8905 8906:Architectures: ppc 8907 8908This capability, if KVM_CHECK_EXTENSION indicates that it is 8909available, means that the kernel has an implementation of the 8910H_RANDOM hypercall backed by a hardware random-number generator. 8911If present, the kernel H_RANDOM handler can be enabled for guest use 8912with the KVM_CAP_PPC_ENABLE_HCALL capability. 8913 89148.3 KVM_CAP_PPC_MMU_RADIX 8915------------------------- 8916 8917:Architectures: ppc 8918 8919This capability, if KVM_CHECK_EXTENSION indicates that it is 8920available, means that the kernel can support guests using the 8921radix MMU defined in Power ISA V3.00 (as implemented in the POWER9 8922processor). 8923 89248.4 KVM_CAP_PPC_MMU_HASH_V3 8925--------------------------- 8926 8927:Architectures: ppc 8928 8929This capability, if KVM_CHECK_EXTENSION indicates that it is 8930available, means that the kernel can support guests using the 8931hashed page table MMU defined in Power ISA V3.00 (as implemented in 8932the POWER9 processor), including in-memory segment tables. 8933 89348.5 KVM_CAP_MIPS_VZ 8935------------------- 8936 8937:Architectures: mips 8938 8939This capability, if KVM_CHECK_EXTENSION on the main kvm handle indicates that 8940it is available, means that full hardware assisted virtualization capabilities 8941of the hardware are available for use through KVM. An appropriate 8942KVM_VM_MIPS_* type must be passed to KVM_CREATE_VM to create a VM which 8943utilises it. 8944 8945If KVM_CHECK_EXTENSION on a kvm VM handle indicates that this capability is 8946available, it means that the VM is using full hardware assisted virtualization 8947capabilities of the hardware. This is useful to check after creating a VM with 8948KVM_VM_MIPS_DEFAULT. 8949 8950The value returned by KVM_CHECK_EXTENSION should be compared against known 8951values (see below). All other values are reserved. This is to allow for the 8952possibility of other hardware assisted virtualization implementations which 8953may be incompatible with the MIPS VZ ASE. 8954 8955== ========================================================================== 8956 0 The trap & emulate implementation is in use to run guest code in user 8957 mode. Guest virtual memory segments are rearranged to fit the guest in the 8958 user mode address space. 8959 8960 1 The MIPS VZ ASE is in use, providing full hardware assisted 8961 virtualization, including standard guest virtual memory segments. 8962== ========================================================================== 8963 89648.7 KVM_CAP_MIPS_64BIT 8965---------------------- 8966 8967:Architectures: mips 8968 8969This capability indicates the supported architecture type of the guest, i.e. the 8970supported register and address width. 8971 8972The values returned when this capability is checked by KVM_CHECK_EXTENSION on a 8973kvm VM handle correspond roughly to the CP0_Config.AT register field, and should 8974be checked specifically against known values (see below). All other values are 8975reserved. 8976 8977== ======================================================================== 8978 0 MIPS32 or microMIPS32. 8979 Both registers and addresses are 32-bits wide. 8980 It will only be possible to run 32-bit guest code. 8981 8982 1 MIPS64 or microMIPS64 with access only to 32-bit compatibility segments. 8983 Registers are 64-bits wide, but addresses are 32-bits wide. 8984 64-bit guest code may run but cannot access MIPS64 memory segments. 8985 It will also be possible to run 32-bit guest code. 8986 8987 2 MIPS64 or microMIPS64 with access to all address segments. 8988 Both registers and addresses are 64-bits wide. 8989 It will be possible to run 64-bit or 32-bit guest code. 8990== ======================================================================== 8991 89928.9 KVM_CAP_ARM_USER_IRQ 8993------------------------ 8994 8995:Architectures: arm64 8996 8997This capability, if KVM_CHECK_EXTENSION indicates that it is available, means 8998that if userspace creates a VM without an in-kernel interrupt controller, it 8999will be notified of changes to the output level of in-kernel emulated devices, 9000which can generate virtual interrupts, presented to the VM. 9001For such VMs, on every return to userspace, the kernel 9002updates the vcpu's run->s.regs.device_irq_level field to represent the actual 9003output level of the device. 9004 9005Whenever kvm detects a change in the device output level, kvm guarantees at 9006least one return to userspace before running the VM. This exit could either 9007be a KVM_EXIT_INTR or any other exit event, like KVM_EXIT_MMIO. This way, 9008userspace can always sample the device output level and re-compute the state of 9009the userspace interrupt controller. Userspace should always check the state 9010of run->s.regs.device_irq_level on every kvm exit. 9011The value in run->s.regs.device_irq_level can represent both level and edge 9012triggered interrupt signals, depending on the device. Edge triggered interrupt 9013signals will exit to userspace with the bit in run->s.regs.device_irq_level 9014set exactly once per edge signal. 9015 9016The field run->s.regs.device_irq_level is available independent of 9017run->kvm_valid_regs or run->kvm_dirty_regs bits. 9018 9019If KVM_CAP_ARM_USER_IRQ is supported, the KVM_CHECK_EXTENSION ioctl returns a 9020number larger than 0 indicating the version of this capability is implemented 9021and thereby which bits in run->s.regs.device_irq_level can signal values. 9022 9023Currently the following bits are defined for the device_irq_level bitmap:: 9024 9025 KVM_CAP_ARM_USER_IRQ >= 1: 9026 9027 KVM_ARM_DEV_EL1_VTIMER - EL1 virtual timer 9028 KVM_ARM_DEV_EL1_PTIMER - EL1 physical timer 9029 KVM_ARM_DEV_PMU - ARM PMU overflow interrupt signal 9030 9031Future versions of kvm may implement additional events. These will get 9032indicated by returning a higher number from KVM_CHECK_EXTENSION and will be 9033listed above. 9034 90358.10 KVM_CAP_PPC_SMT_POSSIBLE 9036----------------------------- 9037 9038:Architectures: ppc 9039 9040Querying this capability returns a bitmap indicating the possible 9041virtual SMT modes that can be set using KVM_CAP_PPC_SMT. If bit N 9042(counting from the right) is set, then a virtual SMT mode of 2^N is 9043available. 9044 90458.12 KVM_CAP_HYPERV_VP_INDEX 9046---------------------------- 9047 9048:Architectures: x86 9049 9050This capability indicates that userspace can load HV_X64_MSR_VP_INDEX msr. Its 9051value is used to denote the target vcpu for a SynIC interrupt. For 9052compatibility, KVM initializes this msr to KVM's internal vcpu index. When this 9053capability is absent, userspace can still query this msr's value. 9054 90558.13 KVM_CAP_S390_AIS_MIGRATION 9056------------------------------- 9057 9058:Architectures: s390 9059 9060This capability indicates if the flic device will be able to get/set the 9061AIS states for migration via the KVM_DEV_FLIC_AISM_ALL attribute and allows 9062to discover this without having to create a flic device. 9063 90648.14 KVM_CAP_S390_PSW 9065--------------------- 9066 9067:Architectures: s390 9068 9069This capability indicates that the PSW is exposed via the kvm_run structure. 9070 90718.15 KVM_CAP_S390_GMAP 9072---------------------- 9073 9074:Architectures: s390 9075 9076This capability indicates that the user space memory used as guest mapping can 9077be anywhere in the user memory address space, as long as the memory slots are 9078aligned and sized to a segment (1MB) boundary. 9079 90808.16 KVM_CAP_S390_COW 9081--------------------- 9082 9083:Architectures: s390 9084 9085This capability indicates that the user space memory used as guest mapping can 9086use copy-on-write semantics as well as dirty pages tracking via read-only page 9087tables. 9088 90898.17 KVM_CAP_S390_BPB 9090--------------------- 9091 9092:Architectures: s390 9093 9094This capability indicates that kvm will implement the interfaces to handle 9095reset, migration and nested KVM for branch prediction blocking. The stfle 9096facility 82 should not be provided to the guest without this capability. 9097 90988.18 KVM_CAP_HYPERV_TLBFLUSH 9099---------------------------- 9100 9101:Architectures: x86 9102 9103This capability indicates that KVM supports paravirtualized Hyper-V TLB Flush 9104hypercalls: 9105HvFlushVirtualAddressSpace, HvFlushVirtualAddressSpaceEx, 9106HvFlushVirtualAddressList, HvFlushVirtualAddressListEx. 9107 91088.19 KVM_CAP_ARM_INJECT_SERROR_ESR 9109---------------------------------- 9110 9111:Architectures: arm64 9112 9113This capability indicates that userspace can specify (via the 9114KVM_SET_VCPU_EVENTS ioctl) the syndrome value reported to the guest when it 9115takes a virtual SError interrupt exception. 9116If KVM advertises this capability, userspace can only specify the ISS field for 9117the ESR syndrome. Other parts of the ESR, such as the EC are generated by the 9118CPU when the exception is taken. If this virtual SError is taken to EL1 using 9119AArch64, this value will be reported in the ISS field of ESR_ELx. 9120 9121See KVM_CAP_VCPU_EVENTS for more details. 9122 91238.20 KVM_CAP_HYPERV_SEND_IPI 9124---------------------------- 9125 9126:Architectures: x86 9127 9128This capability indicates that KVM supports paravirtualized Hyper-V IPI send 9129hypercalls: 9130HvCallSendSyntheticClusterIpi, HvCallSendSyntheticClusterIpiEx. 9131 91328.22 KVM_CAP_S390_VCPU_RESETS 9133----------------------------- 9134 9135:Architectures: s390 9136 9137This capability indicates that the KVM_S390_NORMAL_RESET and 9138KVM_S390_CLEAR_RESET ioctls are available. 9139 91408.23 KVM_CAP_S390_PROTECTED 9141--------------------------- 9142 9143:Architectures: s390 9144 9145This capability indicates that the Ultravisor has been initialized and 9146KVM can therefore start protected VMs. 9147This capability governs the KVM_S390_PV_COMMAND ioctl and the 9148KVM_MP_STATE_LOAD MP_STATE. KVM_SET_MP_STATE can fail for protected 9149guests when the state change is invalid. 9150 91518.24 KVM_CAP_STEAL_TIME 9152----------------------- 9153 9154:Architectures: arm64, x86 9155 9156This capability indicates that KVM supports steal time accounting. 9157When steal time accounting is supported it may be enabled with 9158architecture-specific interfaces. This capability and the architecture- 9159specific interfaces must be consistent, i.e. if one says the feature 9160is supported, than the other should as well and vice versa. For arm64 9161see Documentation/virt/kvm/devices/vcpu.rst "KVM_ARM_VCPU_PVTIME_CTRL". 9162For x86 see Documentation/virt/kvm/x86/msr.rst "MSR_KVM_STEAL_TIME". 9163 91648.25 KVM_CAP_S390_DIAG318 9165------------------------- 9166 9167:Architectures: s390 9168 9169This capability enables a guest to set information about its control program 9170(i.e. guest kernel type and version). The information is helpful during 9171system/firmware service events, providing additional data about the guest 9172environments running on the machine. 9173 9174The information is associated with the DIAGNOSE 0x318 instruction, which sets 9175an 8-byte value consisting of a one-byte Control Program Name Code (CPNC) and 9176a 7-byte Control Program Version Code (CPVC). The CPNC determines what 9177environment the control program is running in (e.g. Linux, z/VM...), and the 9178CPVC is used for information specific to OS (e.g. Linux version, Linux 9179distribution...) 9180 9181If this capability is available, then the CPNC and CPVC can be synchronized 9182between KVM and userspace via the sync regs mechanism (KVM_SYNC_DIAG318). 9183 91848.26 KVM_CAP_X86_USER_SPACE_MSR 9185------------------------------- 9186 9187:Architectures: x86 9188 9189This capability indicates that KVM supports deflection of MSR reads and 9190writes to user space. It can be enabled on a VM level. If enabled, MSR 9191accesses that would usually trigger a #GP by KVM into the guest will 9192instead get bounced to user space through the KVM_EXIT_X86_RDMSR and 9193KVM_EXIT_X86_WRMSR exit notifications. 9194 91958.27 KVM_CAP_X86_MSR_FILTER 9196--------------------------- 9197 9198:Architectures: x86 9199 9200This capability indicates that KVM supports that accesses to user defined MSRs 9201may be rejected. With this capability exposed, KVM exports new VM ioctl 9202KVM_X86_SET_MSR_FILTER which user space can call to specify bitmaps of MSR 9203ranges that KVM should deny access to. 9204 9205In combination with KVM_CAP_X86_USER_SPACE_MSR, this allows user space to 9206trap and emulate MSRs that are outside of the scope of KVM as well as 9207limit the attack surface on KVM's MSR emulation code. 9208 92098.30 KVM_CAP_XEN_HVM 9210-------------------- 9211 9212:Architectures: x86 9213 9214This capability indicates the features that Xen supports for hosting Xen 9215PVHVM guests. Valid flags are:: 9216 9217 #define KVM_XEN_HVM_CONFIG_HYPERCALL_MSR (1 << 0) 9218 #define KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL (1 << 1) 9219 #define KVM_XEN_HVM_CONFIG_SHARED_INFO (1 << 2) 9220 #define KVM_XEN_HVM_CONFIG_RUNSTATE (1 << 3) 9221 #define KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL (1 << 4) 9222 #define KVM_XEN_HVM_CONFIG_EVTCHN_SEND (1 << 5) 9223 #define KVM_XEN_HVM_CONFIG_RUNSTATE_UPDATE_FLAG (1 << 6) 9224 #define KVM_XEN_HVM_CONFIG_PVCLOCK_TSC_UNSTABLE (1 << 7) 9225 9226The KVM_XEN_HVM_CONFIG_HYPERCALL_MSR flag indicates that the KVM_XEN_HVM_CONFIG 9227ioctl is available, for the guest to set its hypercall page. 9228 9229If KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL is also set, the same flag may also be 9230provided in the flags to KVM_XEN_HVM_CONFIG, without providing hypercall page 9231contents, to request that KVM generate hypercall page content automatically 9232and also enable interception of guest hypercalls with KVM_EXIT_XEN. 9233 9234The KVM_XEN_HVM_CONFIG_SHARED_INFO flag indicates the availability of the 9235KVM_XEN_HVM_SET_ATTR, KVM_XEN_HVM_GET_ATTR, KVM_XEN_VCPU_SET_ATTR and 9236KVM_XEN_VCPU_GET_ATTR ioctls, as well as the delivery of exception vectors 9237for event channel upcalls when the evtchn_upcall_pending field of a vcpu's 9238vcpu_info is set. 9239 9240The KVM_XEN_HVM_CONFIG_RUNSTATE flag indicates that the runstate-related 9241features KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR/_CURRENT/_DATA/_ADJUST are 9242supported by the KVM_XEN_VCPU_SET_ATTR/KVM_XEN_VCPU_GET_ATTR ioctls. 9243 9244The KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL flag indicates that IRQ routing entries 9245of the type KVM_IRQ_ROUTING_XEN_EVTCHN are supported, with the priority 9246field set to indicate 2 level event channel delivery. 9247 9248The KVM_XEN_HVM_CONFIG_EVTCHN_SEND flag indicates that KVM supports 9249injecting event channel events directly into the guest with the 9250KVM_XEN_HVM_EVTCHN_SEND ioctl. It also indicates support for the 9251KVM_XEN_ATTR_TYPE_EVTCHN/XEN_VERSION HVM attributes and the 9252KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID/TIMER/UPCALL_VECTOR vCPU attributes. 9253related to event channel delivery, timers, and the XENVER_version 9254interception. 9255 9256The KVM_XEN_HVM_CONFIG_RUNSTATE_UPDATE_FLAG flag indicates that KVM supports 9257the KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG attribute in the KVM_XEN_SET_ATTR 9258and KVM_XEN_GET_ATTR ioctls. This controls whether KVM will set the 9259XEN_RUNSTATE_UPDATE flag in guest memory mapped vcpu_runstate_info during 9260updates of the runstate information. Note that versions of KVM which support 9261the RUNSTATE feature above, but not the RUNSTATE_UPDATE_FLAG feature, will 9262always set the XEN_RUNSTATE_UPDATE flag when updating the guest structure, 9263which is perhaps counterintuitive. When this flag is advertised, KVM will 9264behave more correctly, not using the XEN_RUNSTATE_UPDATE flag until/unless 9265specifically enabled (by the guest making the hypercall, causing the VMM 9266to enable the KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG attribute). 9267 9268The KVM_XEN_HVM_CONFIG_PVCLOCK_TSC_UNSTABLE flag indicates that KVM supports 9269clearing the PVCLOCK_TSC_STABLE_BIT flag in Xen pvclock sources. This will be 9270done when the KVM_CAP_XEN_HVM ioctl sets the 9271KVM_XEN_HVM_CONFIG_PVCLOCK_TSC_UNSTABLE flag. 9272 92738.31 KVM_CAP_SPAPR_MULTITCE 9274--------------------------- 9275 9276:Architectures: ppc 9277:Type: vm 9278 9279This capability means the kernel is capable of handling hypercalls 9280H_PUT_TCE_INDIRECT and H_STUFF_TCE without passing those into the user 9281space. This significantly accelerates DMA operations for PPC KVM guests. 9282User space should expect that its handlers for these hypercalls 9283are not going to be called if user space previously registered LIOBN 9284in KVM (via KVM_CREATE_SPAPR_TCE or similar calls). 9285 9286In order to enable H_PUT_TCE_INDIRECT and H_STUFF_TCE use in the guest, 9287user space might have to advertise it for the guest. For example, 9288IBM pSeries (sPAPR) guest starts using them if "hcall-multi-tce" is 9289present in the "ibm,hypertas-functions" device-tree property. 9290 9291The hypercalls mentioned above may or may not be processed successfully 9292in the kernel based fast path. If they can not be handled by the kernel, 9293they will get passed on to user space. So user space still has to have 9294an implementation for these despite the in kernel acceleration. 9295 9296This capability is always enabled. 9297 92988.32 KVM_CAP_PTP_KVM 9299-------------------- 9300 9301:Architectures: arm64 9302 9303This capability indicates that the KVM virtual PTP service is 9304supported in the host. A VMM can check whether the service is 9305available to the guest on migration. 9306 93078.37 KVM_CAP_S390_PROTECTED_DUMP 9308-------------------------------- 9309 9310:Architectures: s390 9311:Type: vm 9312 9313This capability indicates that KVM and the Ultravisor support dumping 9314PV guests. The `KVM_PV_DUMP` command is available for the 9315`KVM_S390_PV_COMMAND` ioctl and the `KVM_PV_INFO` command provides 9316dump related UV data. Also the vcpu ioctl `KVM_S390_PV_CPU_COMMAND` is 9317available and supports the `KVM_PV_DUMP_CPU` subcommand. 9318 93198.39 KVM_CAP_S390_CPU_TOPOLOGY 9320------------------------------ 9321 9322:Architectures: s390 9323:Type: vm 9324 9325This capability indicates that KVM will provide the S390 CPU Topology 9326facility which consist of the interpretation of the PTF instruction for 9327the function code 2 along with interception and forwarding of both the 9328PTF instruction with function codes 0 or 1 and the STSI(15,1,x) 9329instruction to the userland hypervisor. 9330 9331The stfle facility 11, CPU Topology facility, should not be indicated 9332to the guest without this capability. 9333 9334When this capability is present, KVM provides a new attribute group 9335on vm fd, KVM_S390_VM_CPU_TOPOLOGY. 9336This new attribute allows to get, set or clear the Modified Change 9337Topology Report (MTCR) bit of the SCA through the kvm_device_attr 9338structure. 9339 9340When getting the Modified Change Topology Report value, the attr->addr 9341must point to a byte where the value will be stored or retrieved from. 9342 93438.41 KVM_CAP_VM_TYPES 9344--------------------- 9345 9346:Architectures: x86 9347:Type: system ioctl 9348 9349This capability returns a bitmap of support VM types. The 1-setting of bit @n 9350means the VM type with value @n is supported. Possible values of @n are:: 9351 9352 #define KVM_X86_DEFAULT_VM 0 9353 #define KVM_X86_SW_PROTECTED_VM 1 9354 #define KVM_X86_SEV_VM 2 9355 #define KVM_X86_SEV_ES_VM 3 9356 9357Note, KVM_X86_SW_PROTECTED_VM is currently only for development and testing. 9358Do not use KVM_X86_SW_PROTECTED_VM for "real" VMs, and especially not in 9359production. The behavior and effective ABI for software-protected VMs is 9360unstable. 9361 93628.42 KVM_CAP_PPC_RPT_INVALIDATE 9363------------------------------- 9364 9365:Architectures: ppc 9366 9367This capability indicates that the kernel is capable of handling 9368H_RPT_INVALIDATE hcall. 9369 9370In order to enable the use of H_RPT_INVALIDATE in the guest, 9371user space might have to advertise it for the guest. For example, 9372IBM pSeries (sPAPR) guest starts using it if "hcall-rpt-invalidate" is 9373present in the "ibm,hypertas-functions" device-tree property. 9374 9375This capability is enabled for hypervisors on platforms like POWER9 9376that support radix MMU. 9377 93788.43 KVM_CAP_PPC_AIL_MODE_3 9379--------------------------- 9380 9381:Architectures: ppc 9382 9383This capability indicates that the kernel supports the mode 3 setting for the 9384"Address Translation Mode on Interrupt" aka "Alternate Interrupt Location" 9385resource that is controlled with the H_SET_MODE hypercall. 9386 9387This capability allows a guest kernel to use a better-performance mode for 9388handling interrupts and system calls. 9389 93908.44 KVM_CAP_MEMORY_FAULT_INFO 9391------------------------------ 9392 9393:Architectures: x86 9394 9395The presence of this capability indicates that KVM_RUN will fill 9396kvm_run.memory_fault if KVM cannot resolve a guest page fault VM-Exit, e.g. if 9397there is a valid memslot but no backing VMA for the corresponding host virtual 9398address. 9399 9400The information in kvm_run.memory_fault is valid if and only if KVM_RUN returns 9401an error with errno=EFAULT or errno=EHWPOISON *and* kvm_run.exit_reason is set 9402to KVM_EXIT_MEMORY_FAULT. 9403 9404Note: Userspaces which attempt to resolve memory faults so that they can retry 9405KVM_RUN are encouraged to guard against repeatedly receiving the same 9406error/annotated fault. 9407 9408See KVM_EXIT_MEMORY_FAULT for more information. 9409 94108.45 KVM_CAP_X86_GUEST_MODE 9411--------------------------- 9412 9413:Architectures: x86 9414 9415The presence of this capability indicates that KVM_RUN will update the 9416KVM_RUN_X86_GUEST_MODE bit in kvm_run.flags to indicate whether the 9417vCPU was executing nested guest code when it exited. 9418 94198.46 KVM_CAP_S390_KEYOP 9420----------------------- 9421 9422:Architectures: s390 9423 9424The presence of this capability indicates that the KVM_S390_KEYOP ioctl is 9425available. 9426 9427KVM exits with the register state of either the L1 or L2 guest 9428depending on which executed at the time of an exit. Userspace must 9429take care to differentiate between these cases. 9430 94319. Known KVM API problems 9432========================= 9433 9434In some cases, KVM's API has some inconsistencies or common pitfalls 9435that userspace need to be aware of. This section details some of 9436these issues. 9437 9438Most of them are architecture specific, so the section is split by 9439architecture. 9440 94419.1. x86 9442-------- 9443 9444``KVM_GET_SUPPORTED_CPUID`` issues 9445^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 9446 9447In general, ``KVM_GET_SUPPORTED_CPUID`` is designed so that it is possible 9448to take its result and pass it directly to ``KVM_SET_CPUID2``. This section 9449documents some cases in which that requires some care. 9450 9451Local APIC features 9452~~~~~~~~~~~~~~~~~~~ 9453 9454CPU[EAX=1]:ECX[21] (X2APIC) is reported by ``KVM_GET_SUPPORTED_CPUID``, 9455but it can only be enabled if ``KVM_CREATE_IRQCHIP`` or 9456``KVM_ENABLE_CAP(KVM_CAP_IRQCHIP_SPLIT)`` are used to enable in-kernel emulation of 9457the local APIC. 9458 9459The same is true for the ``KVM_FEATURE_PV_UNHALT`` paravirtualized feature. 9460 9461On older versions of Linux, CPU[EAX=1]:ECX[24] (TSC_DEADLINE) is not reported by 9462``KVM_GET_SUPPORTED_CPUID``, but it can be enabled if ``KVM_CAP_TSC_DEADLINE_TIMER`` 9463is present and the kernel has enabled in-kernel emulation of the local APIC. 9464On newer versions, ``KVM_GET_SUPPORTED_CPUID`` does report the bit as available. 9465 9466CPU topology 9467~~~~~~~~~~~~ 9468 9469Several CPUID values include topology information for the host CPU: 94700x0b and 0x1f for Intel systems, 0x8000001e for AMD systems. Different 9471versions of KVM return different values for this information and userspace 9472should not rely on it. Currently they return all zeroes. 9473 9474If userspace wishes to set up a guest topology, it should be careful that 9475the values of these three leaves differ for each CPU. In particular, 9476the APIC ID is found in EDX for all subleaves of 0x0b and 0x1f, and in EAX 9477for 0x8000001e; the latter also encodes the core id and node id in bits 94787:0 of EBX and ECX respectively. 9479 9480Obsolete ioctls and capabilities 9481^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 9482 9483KVM_CAP_DISABLE_QUIRKS does not let userspace know which quirks are actually 9484available. Use ``KVM_CHECK_EXTENSION(KVM_CAP_DISABLE_QUIRKS2)`` instead if 9485available. 9486 9487Ordering of KVM_GET_*/KVM_SET_* ioctls 9488^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 9489 9490TBD 9491