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 1003:: 1004 1005 struct kvm_xen_hvm_config { 1006 __u32 flags; 1007 __u32 msr; 1008 __u64 blob_addr_32; 1009 __u64 blob_addr_64; 1010 __u8 blob_size_32; 1011 __u8 blob_size_64; 1012 __u8 pad2[30]; 1013 }; 1014 1015If certain flags are returned from the KVM_CAP_XEN_HVM check, they may 1016be set in the flags field of this ioctl: 1017 1018The KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL flag requests KVM to generate 1019the contents of the hypercall page automatically; hypercalls will be 1020intercepted and passed to userspace through KVM_EXIT_XEN. In this 1021case, all of the blob size and address fields must be zero. 1022 1023The KVM_XEN_HVM_CONFIG_EVTCHN_SEND flag indicates to KVM that userspace 1024will always use the KVM_XEN_HVM_EVTCHN_SEND ioctl to deliver event 1025channel interrupts rather than manipulating the guest's shared_info 1026structures directly. This, in turn, may allow KVM to enable features 1027such as intercepting the SCHEDOP_poll hypercall to accelerate PV 1028spinlock operation for the guest. Userspace may still use the ioctl 1029to deliver events if it was advertised, even if userspace does not 1030send this indication that it will always do so 1031 1032No other flags are currently valid in the struct kvm_xen_hvm_config. 1033 10344.29 KVM_GET_CLOCK 1035------------------ 1036 1037:Capability: KVM_CAP_ADJUST_CLOCK 1038:Architectures: x86 1039:Type: vm ioctl 1040:Parameters: struct kvm_clock_data (out) 1041:Returns: 0 on success, -1 on error 1042 1043Gets the current timestamp of kvmclock as seen by the current guest. In 1044conjunction with KVM_SET_CLOCK, it is used to ensure monotonicity on scenarios 1045such as migration. 1046 1047When KVM_CAP_ADJUST_CLOCK is passed to KVM_CHECK_EXTENSION, it returns the 1048set of bits that KVM can return in struct kvm_clock_data's flag member. 1049 1050The following flags are defined: 1051 1052KVM_CLOCK_TSC_STABLE 1053 If set, the returned value is the exact kvmclock 1054 value seen by all VCPUs at the instant when KVM_GET_CLOCK was called. 1055 If clear, the returned value is simply CLOCK_MONOTONIC plus a constant 1056 offset; the offset can be modified with KVM_SET_CLOCK. KVM will try 1057 to make all VCPUs follow this clock, but the exact value read by each 1058 VCPU could differ, because the host TSC is not stable. 1059 1060KVM_CLOCK_REALTIME 1061 If set, the `realtime` field in the kvm_clock_data 1062 structure is populated with the value of the host's real time 1063 clocksource at the instant when KVM_GET_CLOCK was called. If clear, 1064 the `realtime` field does not contain a value. 1065 1066KVM_CLOCK_HOST_TSC 1067 If set, the `host_tsc` field in the kvm_clock_data 1068 structure is populated with the value of the host's timestamp counter (TSC) 1069 at the instant when KVM_GET_CLOCK was called. If clear, the `host_tsc` field 1070 does not contain a value. 1071 1072:: 1073 1074 struct kvm_clock_data { 1075 __u64 clock; /* kvmclock current value */ 1076 __u32 flags; 1077 __u32 pad0; 1078 __u64 realtime; 1079 __u64 host_tsc; 1080 __u32 pad[4]; 1081 }; 1082 1083 10844.30 KVM_SET_CLOCK 1085------------------ 1086 1087:Capability: KVM_CAP_ADJUST_CLOCK 1088:Architectures: x86 1089:Type: vm ioctl 1090:Parameters: struct kvm_clock_data (in) 1091:Returns: 0 on success, -1 on error 1092 1093Sets the current timestamp of kvmclock to the value specified in its parameter. 1094In conjunction with KVM_GET_CLOCK, it is used to ensure monotonicity on scenarios 1095such as migration. 1096 1097The following flags can be passed: 1098 1099KVM_CLOCK_REALTIME 1100 If set, KVM will compare the value of the `realtime` field 1101 with the value of the host's real time clocksource at the instant when 1102 KVM_SET_CLOCK was called. The difference in elapsed time is added to the final 1103 kvmclock value that will be provided to guests. 1104 1105Other flags returned by ``KVM_GET_CLOCK`` are accepted but ignored. 1106 1107:: 1108 1109 struct kvm_clock_data { 1110 __u64 clock; /* kvmclock current value */ 1111 __u32 flags; 1112 __u32 pad0; 1113 __u64 realtime; 1114 __u64 host_tsc; 1115 __u32 pad[4]; 1116 }; 1117 1118 11194.31 KVM_GET_VCPU_EVENTS 1120------------------------ 1121 1122:Capability: KVM_CAP_VCPU_EVENTS 1123:Extended by: KVM_CAP_INTR_SHADOW 1124:Architectures: x86, arm64 1125:Type: vcpu ioctl 1126:Parameters: struct kvm_vcpu_events (out) 1127:Returns: 0 on success, -1 on error 1128 1129X86: 1130^^^^ 1131 1132Gets currently pending exceptions, interrupts, and NMIs as well as related 1133states of the vcpu. 1134 1135:: 1136 1137 struct kvm_vcpu_events { 1138 struct { 1139 __u8 injected; 1140 __u8 nr; 1141 __u8 has_error_code; 1142 __u8 pending; 1143 __u32 error_code; 1144 } exception; 1145 struct { 1146 __u8 injected; 1147 __u8 nr; 1148 __u8 soft; 1149 __u8 shadow; 1150 } interrupt; 1151 struct { 1152 __u8 injected; 1153 __u8 pending; 1154 __u8 masked; 1155 __u8 pad; 1156 } nmi; 1157 __u32 sipi_vector; 1158 __u32 flags; 1159 struct { 1160 __u8 smm; 1161 __u8 pending; 1162 __u8 smm_inside_nmi; 1163 __u8 latched_init; 1164 } smi; 1165 __u8 reserved[27]; 1166 __u8 exception_has_payload; 1167 __u64 exception_payload; 1168 }; 1169 1170The following bits are defined in the flags field: 1171 1172- KVM_VCPUEVENT_VALID_SHADOW may be set to signal that 1173 interrupt.shadow contains a valid state. 1174 1175- KVM_VCPUEVENT_VALID_SMM may be set to signal that smi contains a 1176 valid state. 1177 1178- KVM_VCPUEVENT_VALID_PAYLOAD may be set to signal that the 1179 exception_has_payload, exception_payload, and exception.pending 1180 fields contain a valid state. This bit will be set whenever 1181 KVM_CAP_EXCEPTION_PAYLOAD is enabled. 1182 1183- KVM_VCPUEVENT_VALID_TRIPLE_FAULT may be set to signal that the 1184 triple_fault_pending field contains a valid state. This bit will 1185 be set whenever KVM_CAP_X86_TRIPLE_FAULT_EVENT is enabled. 1186 1187ARM64: 1188^^^^^^ 1189 1190If the guest accesses a device that is being emulated by the host kernel in 1191such a way that a real device would generate a physical SError, KVM may make 1192a virtual SError pending for that VCPU. This system error interrupt remains 1193pending until the guest takes the exception by unmasking PSTATE.A. 1194 1195Running the VCPU may cause it to take a pending SError, or make an access that 1196causes an SError to become pending. The event's description is only valid while 1197the VPCU is not running. 1198 1199This API provides a way to read and write the pending 'event' state that is not 1200visible to the guest. To save, restore or migrate a VCPU the struct representing 1201the state can be read then written using this GET/SET API, along with the other 1202guest-visible registers. It is not possible to 'cancel' an SError that has been 1203made pending. 1204 1205A device being emulated in user-space may also wish to generate an SError. To do 1206this the events structure can be populated by user-space. The current state 1207should be read first, to ensure no existing SError is pending. If an existing 1208SError is pending, the architecture's 'Multiple SError interrupts' rules should 1209be followed. (2.5.3 of DDI0587.a "ARM Reliability, Availability, and 1210Serviceability (RAS) Specification"). 1211 1212SError exceptions always have an ESR value. Some CPUs have the ability to 1213specify what the virtual SError's ESR value should be. These systems will 1214advertise KVM_CAP_ARM_INJECT_SERROR_ESR. In this case exception.has_esr will 1215always have a non-zero value when read, and the agent making an SError pending 1216should specify the ISS field in the lower 24 bits of exception.serror_esr. If 1217the system supports KVM_CAP_ARM_INJECT_SERROR_ESR, but user-space sets the events 1218with exception.has_esr as zero, KVM will choose an ESR. 1219 1220Specifying exception.has_esr on a system that does not support it will return 1221-EINVAL. Setting anything other than the lower 24bits of exception.serror_esr 1222will return -EINVAL. 1223 1224It is not possible to read back a pending external abort (injected via 1225KVM_SET_VCPU_EVENTS or otherwise) because such an exception is always delivered 1226directly to the virtual CPU). 1227 1228:: 1229 1230 struct kvm_vcpu_events { 1231 struct { 1232 __u8 serror_pending; 1233 __u8 serror_has_esr; 1234 __u8 ext_dabt_pending; 1235 /* Align it to 8 bytes */ 1236 __u8 pad[5]; 1237 __u64 serror_esr; 1238 } exception; 1239 __u32 reserved[12]; 1240 }; 1241 12424.32 KVM_SET_VCPU_EVENTS 1243------------------------ 1244 1245:Capability: KVM_CAP_VCPU_EVENTS 1246:Extended by: KVM_CAP_INTR_SHADOW 1247:Architectures: x86, arm64 1248:Type: vcpu ioctl 1249:Parameters: struct kvm_vcpu_events (in) 1250:Returns: 0 on success, -1 on error 1251 1252X86: 1253^^^^ 1254 1255Set pending exceptions, interrupts, and NMIs as well as related states of the 1256vcpu. 1257 1258See KVM_GET_VCPU_EVENTS for the data structure. 1259 1260Fields that may be modified asynchronously by running VCPUs can be excluded 1261from the update. These fields are nmi.pending, sipi_vector, smi.smm, 1262smi.pending. Keep the corresponding bits in the flags field cleared to 1263suppress overwriting the current in-kernel state. The bits are: 1264 1265=============================== ================================== 1266KVM_VCPUEVENT_VALID_NMI_PENDING transfer nmi.pending to the kernel 1267KVM_VCPUEVENT_VALID_SIPI_VECTOR transfer sipi_vector 1268KVM_VCPUEVENT_VALID_SMM transfer the smi sub-struct. 1269=============================== ================================== 1270 1271If KVM_CAP_INTR_SHADOW is available, KVM_VCPUEVENT_VALID_SHADOW can be set in 1272the flags field to signal that interrupt.shadow contains a valid state and 1273shall be written into the VCPU. 1274 1275KVM_VCPUEVENT_VALID_SMM can only be set if KVM_CAP_X86_SMM is available. 1276 1277If KVM_CAP_EXCEPTION_PAYLOAD is enabled, KVM_VCPUEVENT_VALID_PAYLOAD 1278can be set in the flags field to signal that the 1279exception_has_payload, exception_payload, and exception.pending fields 1280contain a valid state and shall be written into the VCPU. 1281 1282If KVM_CAP_X86_TRIPLE_FAULT_EVENT is enabled, KVM_VCPUEVENT_VALID_TRIPLE_FAULT 1283can be set in flags field to signal that the triple_fault field contains 1284a valid state and shall be written into the VCPU. 1285 1286ARM64: 1287^^^^^^ 1288 1289User space may need to inject several types of events to the guest. 1290 1291Set the pending SError exception state for this VCPU. It is not possible to 1292'cancel' an Serror that has been made pending. 1293 1294If the guest performed an access to I/O memory which could not be handled by 1295userspace, for example because of missing instruction syndrome decode 1296information or because there is no device mapped at the accessed IPA, then 1297userspace can ask the kernel to inject an external abort using the address 1298from the exiting fault on the VCPU. It is a programming error to set 1299ext_dabt_pending after an exit which was not either KVM_EXIT_MMIO or 1300KVM_EXIT_ARM_NISV. This feature is only available if the system supports 1301KVM_CAP_ARM_INJECT_EXT_DABT. This is a helper which provides commonality in 1302how userspace reports accesses for the above cases to guests, across different 1303userspace implementations. Nevertheless, userspace can still emulate all Arm 1304exceptions by manipulating individual registers using the KVM_SET_ONE_REG API. 1305 1306See KVM_GET_VCPU_EVENTS for the data structure. 1307 1308 13094.33 KVM_GET_DEBUGREGS 1310---------------------- 1311 1312:Capability: KVM_CAP_DEBUGREGS 1313:Architectures: x86 1314:Type: vcpu ioctl 1315:Parameters: struct kvm_debugregs (out) 1316:Returns: 0 on success, -1 on error 1317 1318Reads debug registers from the vcpu. 1319 1320:: 1321 1322 struct kvm_debugregs { 1323 __u64 db[4]; 1324 __u64 dr6; 1325 __u64 dr7; 1326 __u64 flags; 1327 __u64 reserved[9]; 1328 }; 1329 1330 13314.34 KVM_SET_DEBUGREGS 1332---------------------- 1333 1334:Capability: KVM_CAP_DEBUGREGS 1335:Architectures: x86 1336:Type: vcpu ioctl 1337:Parameters: struct kvm_debugregs (in) 1338:Returns: 0 on success, -1 on error 1339 1340Writes debug registers into the vcpu. 1341 1342See KVM_GET_DEBUGREGS for the data structure. The flags field is unused 1343yet and must be cleared on entry. 1344 1345 13464.35 KVM_SET_USER_MEMORY_REGION 1347------------------------------- 1348 1349:Capability: KVM_CAP_USER_MEMORY 1350:Architectures: all 1351:Type: vm ioctl 1352:Parameters: struct kvm_userspace_memory_region (in) 1353:Returns: 0 on success, -1 on error 1354 1355:: 1356 1357 struct kvm_userspace_memory_region { 1358 __u32 slot; 1359 __u32 flags; 1360 __u64 guest_phys_addr; 1361 __u64 memory_size; /* bytes */ 1362 __u64 userspace_addr; /* start of the userspace allocated memory */ 1363 }; 1364 1365 /* for kvm_userspace_memory_region::flags */ 1366 #define KVM_MEM_LOG_DIRTY_PAGES (1UL << 0) 1367 #define KVM_MEM_READONLY (1UL << 1) 1368 1369This ioctl allows the user to create, modify or delete a guest physical 1370memory slot. Bits 0-15 of "slot" specify the slot id and this value 1371should be less than the maximum number of user memory slots supported per 1372VM. The maximum allowed slots can be queried using KVM_CAP_NR_MEMSLOTS. 1373Slots may not overlap in guest physical address space. 1374 1375If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 of "slot" 1376specifies the address space which is being modified. They must be 1377less than the value that KVM_CHECK_EXTENSION returns for the 1378KVM_CAP_MULTI_ADDRESS_SPACE capability. Slots in separate address spaces 1379are unrelated; the restriction on overlapping slots only applies within 1380each address space. 1381 1382Deleting a slot is done by passing zero for memory_size. When changing 1383an existing slot, it may be moved in the guest physical memory space, 1384or its flags may be modified, but it may not be resized. 1385 1386Memory for the region is taken starting at the address denoted by the 1387field userspace_addr, which must point at user addressable memory for 1388the entire memory slot size. Any object may back this memory, including 1389anonymous memory, ordinary files, and hugetlbfs. 1390 1391On architectures that support a form of address tagging, userspace_addr must 1392be an untagged address. 1393 1394It is recommended that the lower 21 bits of guest_phys_addr and userspace_addr 1395be identical. This allows large pages in the guest to be backed by large 1396pages in the host. 1397 1398The flags field supports two flags: KVM_MEM_LOG_DIRTY_PAGES and 1399KVM_MEM_READONLY. The former can be set to instruct KVM to keep track of 1400writes to memory within the slot. See KVM_GET_DIRTY_LOG ioctl to know how to 1401use it. The latter can be set, if KVM_CAP_READONLY_MEM capability allows it, 1402to make a new slot read-only. In this case, writes to this memory will be 1403posted to userspace as KVM_EXIT_MMIO exits. 1404 1405When the KVM_CAP_SYNC_MMU capability is available, changes in the backing of 1406the memory region are automatically reflected into the guest. For example, an 1407mmap() that affects the region will be made visible immediately. Another 1408example is madvise(MADV_DROP). 1409 1410Note: On arm64, a write generated by the page-table walker (to update 1411the Access and Dirty flags, for example) never results in a 1412KVM_EXIT_MMIO exit when the slot has the KVM_MEM_READONLY flag. This 1413is because KVM cannot provide the data that would be written by the 1414page-table walker, making it impossible to emulate the access. 1415Instead, an abort (data abort if the cause of the page-table update 1416was a load or a store, instruction abort if it was an instruction 1417fetch) is injected in the guest. 1418 1419S390: 1420^^^^^ 1421 1422Returns -EINVAL if the VM has the KVM_VM_S390_UCONTROL flag set. 1423Returns -EINVAL if called on a protected VM. 1424 14254.36 KVM_SET_TSS_ADDR 1426--------------------- 1427 1428:Capability: KVM_CAP_SET_TSS_ADDR 1429:Architectures: x86 1430:Type: vm ioctl 1431:Parameters: unsigned long tss_address (in) 1432:Returns: 0 on success, -1 on error 1433 1434This ioctl defines the physical address of a three-page region in the guest 1435physical address space. The region must be within the first 4GB of the 1436guest physical address space and must not conflict with any memory slot 1437or any mmio address. The guest may malfunction if it accesses this memory 1438region. 1439 1440This ioctl is required on Intel-based hosts. This is needed on Intel hardware 1441because of a quirk in the virtualization implementation (see the internals 1442documentation when it pops into existence). 1443 1444 1445.. _KVM_ENABLE_CAP: 1446 14474.37 KVM_ENABLE_CAP 1448------------------- 1449 1450:Capability: KVM_CAP_ENABLE_CAP 1451:Architectures: mips, ppc, s390, x86, loongarch 1452:Type: vcpu ioctl 1453:Parameters: struct kvm_enable_cap (in) 1454:Returns: 0 on success; -1 on error 1455 1456:Capability: KVM_CAP_ENABLE_CAP_VM 1457:Architectures: all 1458:Type: vm ioctl 1459:Parameters: struct kvm_enable_cap (in) 1460:Returns: 0 on success; -1 on error 1461 1462.. note:: 1463 1464 Not all extensions are enabled by default. Using this ioctl the application 1465 can enable an extension, making it available to the guest. 1466 1467On systems that do not support this ioctl, it always fails. On systems that 1468do support it, it only works for extensions that are supported for enablement. 1469 1470To check if a capability can be enabled, the KVM_CHECK_EXTENSION ioctl should 1471be used. 1472 1473:: 1474 1475 struct kvm_enable_cap { 1476 /* in */ 1477 __u32 cap; 1478 1479The capability that is supposed to get enabled. 1480 1481:: 1482 1483 __u32 flags; 1484 1485A bitfield indicating future enhancements. Has to be 0 for now. 1486 1487:: 1488 1489 __u64 args[4]; 1490 1491Arguments for enabling a feature. If a feature needs initial values to 1492function properly, this is the place to put them. 1493 1494:: 1495 1496 __u8 pad[64]; 1497 }; 1498 1499The vcpu ioctl should be used for vcpu-specific capabilities, the vm ioctl 1500for vm-wide capabilities. 1501 15024.38 KVM_GET_MP_STATE 1503--------------------- 1504 1505:Capability: KVM_CAP_MP_STATE 1506:Architectures: x86, s390, arm64, riscv, loongarch 1507:Type: vcpu ioctl 1508:Parameters: struct kvm_mp_state (out) 1509:Returns: 0 on success; -1 on error 1510 1511:: 1512 1513 struct kvm_mp_state { 1514 __u32 mp_state; 1515 }; 1516 1517Returns the vcpu's current "multiprocessing state" (though also valid on 1518uniprocessor guests). 1519 1520Possible values are: 1521 1522 ========================== =============================================== 1523 KVM_MP_STATE_RUNNABLE the vcpu is currently running 1524 [x86,arm64,riscv,loongarch] 1525 KVM_MP_STATE_UNINITIALIZED the vcpu is an application processor (AP) 1526 which has not yet received an INIT signal [x86] 1527 KVM_MP_STATE_INIT_RECEIVED the vcpu has received an INIT signal, and is 1528 now ready for a SIPI [x86] 1529 KVM_MP_STATE_HALTED the vcpu has executed a HLT instruction and 1530 is waiting for an interrupt [x86] 1531 KVM_MP_STATE_SIPI_RECEIVED the vcpu has just received a SIPI (vector 1532 accessible via KVM_GET_VCPU_EVENTS) [x86] 1533 KVM_MP_STATE_STOPPED the vcpu is stopped [s390,arm64,riscv] 1534 KVM_MP_STATE_CHECK_STOP the vcpu is in a special error state [s390] 1535 KVM_MP_STATE_OPERATING the vcpu is operating (running or halted) 1536 [s390] 1537 KVM_MP_STATE_LOAD the vcpu is in a special load/startup state 1538 [s390] 1539 KVM_MP_STATE_SUSPENDED the vcpu is in a suspend state and is waiting 1540 for a wakeup event [arm64] 1541 ========================== =============================================== 1542 1543On x86, this ioctl is only useful after KVM_CREATE_IRQCHIP. Without an 1544in-kernel irqchip, the multiprocessing state must be maintained by userspace on 1545these architectures. 1546 1547For arm64: 1548^^^^^^^^^^ 1549 1550If a vCPU is in the KVM_MP_STATE_SUSPENDED state, KVM will emulate the 1551architectural execution of a WFI instruction. 1552 1553If a wakeup event is recognized, KVM will exit to userspace with a 1554KVM_SYSTEM_EVENT exit, where the event type is KVM_SYSTEM_EVENT_WAKEUP. If 1555userspace wants to honor the wakeup, it must set the vCPU's MP state to 1556KVM_MP_STATE_RUNNABLE. If it does not, KVM will continue to await a wakeup 1557event in subsequent calls to KVM_RUN. 1558 1559.. warning:: 1560 1561 If userspace intends to keep the vCPU in a SUSPENDED state, it is 1562 strongly recommended that userspace take action to suppress the 1563 wakeup event (such as masking an interrupt). Otherwise, subsequent 1564 calls to KVM_RUN will immediately exit with a KVM_SYSTEM_EVENT_WAKEUP 1565 event and inadvertently waste CPU cycles. 1566 1567 Additionally, if userspace takes action to suppress a wakeup event, 1568 it is strongly recommended that it also restores the vCPU to its 1569 original state when the vCPU is made RUNNABLE again. For example, 1570 if userspace masked a pending interrupt to suppress the wakeup, 1571 the interrupt should be unmasked before returning control to the 1572 guest. 1573 1574For riscv: 1575^^^^^^^^^^ 1576 1577The only states that are valid are KVM_MP_STATE_STOPPED and 1578KVM_MP_STATE_RUNNABLE which reflect if the vcpu is paused or not. 1579 1580On LoongArch, only the KVM_MP_STATE_RUNNABLE state is used to reflect 1581whether the vcpu is runnable. 1582 15834.39 KVM_SET_MP_STATE 1584--------------------- 1585 1586:Capability: KVM_CAP_MP_STATE 1587:Architectures: x86, s390, arm64, riscv, loongarch 1588:Type: vcpu ioctl 1589:Parameters: struct kvm_mp_state (in) 1590:Returns: 0 on success; -1 on error 1591 1592Sets the vcpu's current "multiprocessing state"; see KVM_GET_MP_STATE for 1593arguments. 1594 1595On x86, this ioctl is only useful after KVM_CREATE_IRQCHIP. Without an 1596in-kernel irqchip, the multiprocessing state must be maintained by userspace on 1597these architectures. 1598 1599For arm64/riscv: 1600^^^^^^^^^^^^^^^^ 1601 1602The only states that are valid are KVM_MP_STATE_STOPPED and 1603KVM_MP_STATE_RUNNABLE which reflect if the vcpu should be paused or not. 1604 1605On LoongArch, only the KVM_MP_STATE_RUNNABLE state is used to reflect 1606whether the vcpu is runnable. 1607 16084.40 KVM_SET_IDENTITY_MAP_ADDR 1609------------------------------ 1610 1611:Capability: KVM_CAP_SET_IDENTITY_MAP_ADDR 1612:Architectures: x86 1613:Type: vm ioctl 1614:Parameters: unsigned long identity (in) 1615:Returns: 0 on success, -1 on error 1616 1617This ioctl defines the physical address of a one-page region in the guest 1618physical address space. The region must be within the first 4GB of the 1619guest physical address space and must not conflict with any memory slot 1620or any mmio address. The guest may malfunction if it accesses this memory 1621region. 1622 1623Setting the address to 0 will result in resetting the address to its default 1624(0xfffbc000). 1625 1626This ioctl is required on Intel-based hosts. This is needed on Intel hardware 1627because of a quirk in the virtualization implementation (see the internals 1628documentation when it pops into existence). 1629 1630Fails if any VCPU has already been created. 1631 16324.41 KVM_SET_BOOT_CPU_ID 1633------------------------ 1634 1635:Capability: KVM_CAP_SET_BOOT_CPU_ID 1636:Architectures: x86 1637:Type: vm ioctl 1638:Parameters: unsigned long vcpu_id 1639:Returns: 0 on success, -1 on error 1640 1641Define which vcpu is the Bootstrap Processor (BSP). Values are the same 1642as the vcpu id in KVM_CREATE_VCPU. If this ioctl is not called, the default 1643is vcpu 0. This ioctl has to be called before vcpu creation, 1644otherwise it will return EBUSY error. 1645 1646 16474.42 KVM_GET_XSAVE 1648------------------ 1649 1650:Capability: KVM_CAP_XSAVE 1651:Architectures: x86 1652:Type: vcpu ioctl 1653:Parameters: struct kvm_xsave (out) 1654:Returns: 0 on success, -1 on error 1655 1656 1657:: 1658 1659 struct kvm_xsave { 1660 __u32 region[1024]; 1661 __u32 extra[0]; 1662 }; 1663 1664This ioctl would copy current vcpu's xsave struct to the userspace. 1665 1666 16674.43 KVM_SET_XSAVE 1668------------------ 1669 1670:Capability: KVM_CAP_XSAVE and KVM_CAP_XSAVE2 1671:Architectures: x86 1672:Type: vcpu ioctl 1673:Parameters: struct kvm_xsave (in) 1674:Returns: 0 on success, -1 on error 1675 1676:: 1677 1678 1679 struct kvm_xsave { 1680 __u32 region[1024]; 1681 __u32 extra[0]; 1682 }; 1683 1684This ioctl would copy userspace's xsave struct to the kernel. It copies 1685as many bytes as are returned by KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2), 1686when invoked on the vm file descriptor. The size value returned by 1687KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2) will always be at least 4096. 1688Currently, it is only greater than 4096 if a dynamic feature has been 1689enabled with ``arch_prctl()``, but this may change in the future. 1690 1691The offsets of the state save areas in struct kvm_xsave follow the 1692contents of CPUID leaf 0xD on the host. 1693 1694 16954.44 KVM_GET_XCRS 1696----------------- 1697 1698:Capability: KVM_CAP_XCRS 1699:Architectures: x86 1700:Type: vcpu ioctl 1701:Parameters: struct kvm_xcrs (out) 1702:Returns: 0 on success, -1 on error 1703 1704:: 1705 1706 struct kvm_xcr { 1707 __u32 xcr; 1708 __u32 reserved; 1709 __u64 value; 1710 }; 1711 1712 struct kvm_xcrs { 1713 __u32 nr_xcrs; 1714 __u32 flags; 1715 struct kvm_xcr xcrs[KVM_MAX_XCRS]; 1716 __u64 padding[16]; 1717 }; 1718 1719This ioctl would copy current vcpu's xcrs to the userspace. 1720 1721 17224.45 KVM_SET_XCRS 1723----------------- 1724 1725:Capability: KVM_CAP_XCRS 1726:Architectures: x86 1727:Type: vcpu ioctl 1728:Parameters: struct kvm_xcrs (in) 1729:Returns: 0 on success, -1 on error 1730 1731:: 1732 1733 struct kvm_xcr { 1734 __u32 xcr; 1735 __u32 reserved; 1736 __u64 value; 1737 }; 1738 1739 struct kvm_xcrs { 1740 __u32 nr_xcrs; 1741 __u32 flags; 1742 struct kvm_xcr xcrs[KVM_MAX_XCRS]; 1743 __u64 padding[16]; 1744 }; 1745 1746This ioctl would set vcpu's xcr to the value userspace specified. 1747 1748 17494.46 KVM_GET_SUPPORTED_CPUID 1750---------------------------- 1751 1752:Capability: KVM_CAP_EXT_CPUID 1753:Architectures: x86 1754:Type: system ioctl 1755:Parameters: struct kvm_cpuid2 (in/out) 1756:Returns: 0 on success, -1 on error 1757 1758:: 1759 1760 struct kvm_cpuid2 { 1761 __u32 nent; 1762 __u32 padding; 1763 struct kvm_cpuid_entry2 entries[0]; 1764 }; 1765 1766 #define KVM_CPUID_FLAG_SIGNIFCANT_INDEX BIT(0) 1767 #define KVM_CPUID_FLAG_STATEFUL_FUNC BIT(1) /* deprecated */ 1768 #define KVM_CPUID_FLAG_STATE_READ_NEXT BIT(2) /* deprecated */ 1769 1770 struct kvm_cpuid_entry2 { 1771 __u32 function; 1772 __u32 index; 1773 __u32 flags; 1774 __u32 eax; 1775 __u32 ebx; 1776 __u32 ecx; 1777 __u32 edx; 1778 __u32 padding[3]; 1779 }; 1780 1781This ioctl returns x86 cpuid features which are supported by both the 1782hardware and kvm in its default configuration. Userspace can use the 1783information returned by this ioctl to construct cpuid information (for 1784KVM_SET_CPUID2) that is consistent with hardware, kernel, and 1785userspace capabilities, and with user requirements (for example, the 1786user may wish to constrain cpuid to emulate older hardware, or for 1787feature consistency across a cluster). 1788 1789Dynamically-enabled feature bits need to be requested with 1790``arch_prctl()`` before calling this ioctl. Feature bits that have not 1791been requested are excluded from the result. 1792 1793Note that certain capabilities, such as KVM_CAP_X86_DISABLE_EXITS, may 1794expose cpuid features (e.g. MONITOR) which are not supported by kvm in 1795its default configuration. If userspace enables such capabilities, it 1796is responsible for modifying the results of this ioctl appropriately. 1797 1798Userspace invokes KVM_GET_SUPPORTED_CPUID by passing a kvm_cpuid2 structure 1799with the 'nent' field indicating the number of entries in the variable-size 1800array 'entries'. If the number of entries is too low to describe the cpu 1801capabilities, an error (E2BIG) is returned. If the number is too high, 1802the 'nent' field is adjusted and an error (ENOMEM) is returned. If the 1803number is just right, the 'nent' field is adjusted to the number of valid 1804entries in the 'entries' array, which is then filled. 1805 1806The entries returned are the host cpuid as returned by the cpuid instruction, 1807with unknown or unsupported features masked out. Some features (for example, 1808x2apic), may not be present in the host cpu, but are exposed by kvm if it can 1809emulate them efficiently. The fields in each entry are defined as follows: 1810 1811 function: 1812 the eax value used to obtain the entry 1813 1814 index: 1815 the ecx value used to obtain the entry (for entries that are 1816 affected by ecx) 1817 1818 flags: 1819 an OR of zero or more of the following: 1820 1821 KVM_CPUID_FLAG_SIGNIFCANT_INDEX: 1822 if the index field is valid 1823 1824 eax, ebx, ecx, edx: 1825 the values returned by the cpuid instruction for 1826 this function/index combination 1827 1828The TSC deadline timer feature (CPUID leaf 1, ecx[24]) is always returned 1829as false, since the feature depends on KVM_CREATE_IRQCHIP for local APIC 1830support. Instead it is reported via:: 1831 1832 ioctl(KVM_CHECK_EXTENSION, KVM_CAP_TSC_DEADLINE_TIMER) 1833 1834if that returns true and you use KVM_CREATE_IRQCHIP, or if you emulate the 1835feature in userspace, then you can enable the feature for KVM_SET_CPUID2. 1836 1837 18384.47 KVM_PPC_GET_PVINFO 1839----------------------- 1840 1841:Capability: KVM_CAP_PPC_GET_PVINFO 1842:Architectures: ppc 1843:Type: vm ioctl 1844:Parameters: struct kvm_ppc_pvinfo (out) 1845:Returns: 0 on success, !0 on error 1846 1847:: 1848 1849 struct kvm_ppc_pvinfo { 1850 __u32 flags; 1851 __u32 hcall[4]; 1852 __u8 pad[108]; 1853 }; 1854 1855This ioctl fetches PV specific information that need to be passed to the guest 1856using the device tree or other means from vm context. 1857 1858The hcall array defines 4 instructions that make up a hypercall. 1859 1860If any additional field gets added to this structure later on, a bit for that 1861additional piece of information will be set in the flags bitmap. 1862 1863The flags bitmap is defined as:: 1864 1865 /* the host supports the ePAPR idle hcall 1866 #define KVM_PPC_PVINFO_FLAGS_EV_IDLE (1<<0) 1867 18684.52 KVM_SET_GSI_ROUTING 1869------------------------ 1870 1871:Capability: KVM_CAP_IRQ_ROUTING 1872:Architectures: x86 s390 arm64 1873:Type: vm ioctl 1874:Parameters: struct kvm_irq_routing (in) 1875:Returns: 0 on success, -1 on error 1876 1877Sets the GSI routing table entries, overwriting any previously set entries. 1878 1879On arm64, GSI routing has the following limitation: 1880 1881- GSI routing does not apply to KVM_IRQ_LINE but only to KVM_IRQFD. 1882 1883:: 1884 1885 struct kvm_irq_routing { 1886 __u32 nr; 1887 __u32 flags; 1888 struct kvm_irq_routing_entry entries[0]; 1889 }; 1890 1891No flags are specified so far, the corresponding field must be set to zero. 1892 1893:: 1894 1895 struct kvm_irq_routing_entry { 1896 __u32 gsi; 1897 __u32 type; 1898 __u32 flags; 1899 __u32 pad; 1900 union { 1901 struct kvm_irq_routing_irqchip irqchip; 1902 struct kvm_irq_routing_msi msi; 1903 struct kvm_irq_routing_s390_adapter adapter; 1904 struct kvm_irq_routing_hv_sint hv_sint; 1905 struct kvm_irq_routing_xen_evtchn xen_evtchn; 1906 __u32 pad[8]; 1907 } u; 1908 }; 1909 1910 /* gsi routing entry types */ 1911 #define KVM_IRQ_ROUTING_IRQCHIP 1 1912 #define KVM_IRQ_ROUTING_MSI 2 1913 #define KVM_IRQ_ROUTING_S390_ADAPTER 3 1914 #define KVM_IRQ_ROUTING_HV_SINT 4 1915 #define KVM_IRQ_ROUTING_XEN_EVTCHN 5 1916 1917flags: 1918 1919- KVM_MSI_VALID_DEVID: used along with KVM_IRQ_ROUTING_MSI routing entry 1920 type, specifies that the devid field contains a valid value. The per-VM 1921 KVM_CAP_MSI_DEVID capability advertises the requirement to provide 1922 the device ID. If this capability is not available, userspace should 1923 never set the KVM_MSI_VALID_DEVID flag as the ioctl might fail. 1924- zero otherwise 1925 1926:: 1927 1928 struct kvm_irq_routing_irqchip { 1929 __u32 irqchip; 1930 __u32 pin; 1931 }; 1932 1933 struct kvm_irq_routing_msi { 1934 __u32 address_lo; 1935 __u32 address_hi; 1936 __u32 data; 1937 union { 1938 __u32 pad; 1939 __u32 devid; 1940 }; 1941 }; 1942 1943If KVM_MSI_VALID_DEVID is set, devid contains a unique device identifier 1944for the device that wrote the MSI message. For PCI, this is usually a 1945BDF identifier in the lower 16 bits. 1946 1947On x86, address_hi is ignored unless the KVM_X2APIC_API_USE_32BIT_IDS 1948feature of KVM_CAP_X2APIC_API capability is enabled. If it is enabled, 1949address_hi bits 31-8 provide bits 31-8 of the destination id. Bits 7-0 of 1950address_hi must be zero. 1951 1952:: 1953 1954 struct kvm_irq_routing_s390_adapter { 1955 __u64 ind_addr; 1956 __u64 summary_addr; 1957 __u64 ind_offset; 1958 __u32 summary_offset; 1959 __u32 adapter_id; 1960 }; 1961 1962 struct kvm_irq_routing_hv_sint { 1963 __u32 vcpu; 1964 __u32 sint; 1965 }; 1966 1967 struct kvm_irq_routing_xen_evtchn { 1968 __u32 port; 1969 __u32 vcpu; 1970 __u32 priority; 1971 }; 1972 1973 1974When KVM_CAP_XEN_HVM includes the KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL bit 1975in its indication of supported features, routing to Xen event channels 1976is supported. Although the priority field is present, only the value 1977KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL is supported, which means delivery by 19782 level event channels. FIFO event channel support may be added in 1979the future. 1980 1981 19824.55 KVM_SET_TSC_KHZ 1983-------------------- 1984 1985:Capability: KVM_CAP_TSC_CONTROL / KVM_CAP_VM_TSC_CONTROL 1986:Architectures: x86 1987:Type: vcpu ioctl / vm ioctl 1988:Parameters: virtual tsc_khz 1989:Returns: 0 on success, -1 on error 1990 1991Specifies the tsc frequency for the virtual machine. The unit of the 1992frequency is KHz. 1993 1994If the KVM_CAP_VM_TSC_CONTROL capability is advertised, this can also 1995be used as a vm ioctl to set the initial tsc frequency of subsequently 1996created vCPUs. 1997 19984.56 KVM_GET_TSC_KHZ 1999-------------------- 2000 2001:Capability: KVM_CAP_GET_TSC_KHZ / KVM_CAP_VM_TSC_CONTROL 2002:Architectures: x86 2003:Type: vcpu ioctl / vm ioctl 2004:Parameters: none 2005:Returns: virtual tsc-khz on success, negative value on error 2006 2007Returns the tsc frequency of the guest. The unit of the return value is 2008KHz. If the host has unstable tsc this ioctl returns -EIO instead as an 2009error. 2010 2011 20124.57 KVM_GET_LAPIC 2013------------------ 2014 2015:Capability: KVM_CAP_IRQCHIP 2016:Architectures: x86 2017:Type: vcpu ioctl 2018:Parameters: struct kvm_lapic_state (out) 2019:Returns: 0 on success, -1 on error 2020 2021:: 2022 2023 #define KVM_APIC_REG_SIZE 0x400 2024 struct kvm_lapic_state { 2025 char regs[KVM_APIC_REG_SIZE]; 2026 }; 2027 2028Reads the Local APIC registers and copies them into the input argument. The 2029data format and layout are the same as documented in the architecture manual. 2030 2031If KVM_X2APIC_API_USE_32BIT_IDS feature of KVM_CAP_X2APIC_API is 2032enabled, then the format of APIC_ID register depends on the APIC mode 2033(reported by MSR_IA32_APICBASE) of its VCPU. x2APIC stores APIC ID in 2034the APIC_ID register (bytes 32-35). xAPIC only allows an 8-bit APIC ID 2035which is stored in bits 31-24 of the APIC register, or equivalently in 2036byte 35 of struct kvm_lapic_state's regs field. KVM_GET_LAPIC must then 2037be called after MSR_IA32_APICBASE has been set with KVM_SET_MSR. 2038 2039If KVM_X2APIC_API_USE_32BIT_IDS feature is disabled, struct kvm_lapic_state 2040always uses xAPIC format. 2041 2042 20434.58 KVM_SET_LAPIC 2044------------------ 2045 2046:Capability: KVM_CAP_IRQCHIP 2047:Architectures: x86 2048:Type: vcpu ioctl 2049:Parameters: struct kvm_lapic_state (in) 2050:Returns: 0 on success, -1 on error 2051 2052:: 2053 2054 #define KVM_APIC_REG_SIZE 0x400 2055 struct kvm_lapic_state { 2056 char regs[KVM_APIC_REG_SIZE]; 2057 }; 2058 2059Copies the input argument into the Local APIC registers. The data format 2060and layout are the same as documented in the architecture manual. 2061 2062The format of the APIC ID register (bytes 32-35 of struct kvm_lapic_state's 2063regs field) depends on the state of the KVM_CAP_X2APIC_API capability. 2064See the note in KVM_GET_LAPIC. 2065 2066 20674.59 KVM_IOEVENTFD 2068------------------ 2069 2070:Capability: KVM_CAP_IOEVENTFD 2071:Architectures: all 2072:Type: vm ioctl 2073:Parameters: struct kvm_ioeventfd (in) 2074:Returns: 0 on success, !0 on error 2075 2076This ioctl attaches or detaches an ioeventfd to a legal pio/mmio address 2077within the guest. A guest write in the registered address will signal the 2078provided event instead of triggering an exit. 2079 2080:: 2081 2082 struct kvm_ioeventfd { 2083 __u64 datamatch; 2084 __u64 addr; /* legal pio/mmio address */ 2085 __u32 len; /* 0, 1, 2, 4, or 8 bytes */ 2086 __s32 fd; 2087 __u32 flags; 2088 __u8 pad[36]; 2089 }; 2090 2091For the special case of virtio-ccw devices on s390, the ioevent is matched 2092to a subchannel/virtqueue tuple instead. 2093 2094The following flags are defined:: 2095 2096 #define KVM_IOEVENTFD_FLAG_DATAMATCH (1 << kvm_ioeventfd_flag_nr_datamatch) 2097 #define KVM_IOEVENTFD_FLAG_PIO (1 << kvm_ioeventfd_flag_nr_pio) 2098 #define KVM_IOEVENTFD_FLAG_DEASSIGN (1 << kvm_ioeventfd_flag_nr_deassign) 2099 #define KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY \ 2100 (1 << kvm_ioeventfd_flag_nr_virtio_ccw_notify) 2101 2102If datamatch flag is set, the event will be signaled only if the written value 2103to the registered address is equal to datamatch in struct kvm_ioeventfd. 2104 2105For virtio-ccw devices, addr contains the subchannel id and datamatch the 2106virtqueue index. 2107 2108With KVM_CAP_IOEVENTFD_ANY_LENGTH, a zero length ioeventfd is allowed, and 2109the kernel will ignore the length of guest write and may get a faster vmexit. 2110The speedup may only apply to specific architectures, but the ioeventfd will 2111work anyway. 2112 21134.60 KVM_DIRTY_TLB 2114------------------ 2115 2116:Capability: KVM_CAP_SW_TLB 2117:Architectures: ppc 2118:Type: vcpu ioctl 2119:Parameters: struct kvm_dirty_tlb (in) 2120:Returns: 0 on success, -1 on error 2121 2122:: 2123 2124 struct kvm_dirty_tlb { 2125 __u64 bitmap; 2126 __u32 num_dirty; 2127 }; 2128 2129This must be called whenever userspace has changed an entry in the shared 2130TLB, prior to calling KVM_RUN on the associated vcpu. 2131 2132The "bitmap" field is the userspace address of an array. This array 2133consists of a number of bits, equal to the total number of TLB entries as 2134determined by the last successful call to ``KVM_ENABLE_CAP(KVM_CAP_SW_TLB)``, 2135rounded up to the nearest multiple of 64. 2136 2137Each bit corresponds to one TLB entry, ordered the same as in the shared TLB 2138array. 2139 2140The array is little-endian: the bit 0 is the least significant bit of the 2141first byte, bit 8 is the least significant bit of the second byte, etc. 2142This avoids any complications with differing word sizes. 2143 2144The "num_dirty" field is a performance hint for KVM to determine whether it 2145should skip processing the bitmap and just invalidate everything. It must 2146be set to the number of set bits in the bitmap. 2147 2148 21494.62 KVM_CREATE_SPAPR_TCE 2150------------------------- 2151 2152:Capability: KVM_CAP_SPAPR_TCE 2153:Architectures: powerpc 2154:Type: vm ioctl 2155:Parameters: struct kvm_create_spapr_tce (in) 2156:Returns: file descriptor for manipulating the created TCE table 2157 2158This creates a virtual TCE (translation control entry) table, which 2159is an IOMMU for PAPR-style virtual I/O. It is used to translate 2160logical addresses used in virtual I/O into guest physical addresses, 2161and provides a scatter/gather capability for PAPR virtual I/O. 2162 2163:: 2164 2165 /* for KVM_CAP_SPAPR_TCE */ 2166 struct kvm_create_spapr_tce { 2167 __u64 liobn; 2168 __u32 window_size; 2169 }; 2170 2171The liobn field gives the logical IO bus number for which to create a 2172TCE table. The window_size field specifies the size of the DMA window 2173which this TCE table will translate - the table will contain one 64 2174bit TCE entry for every 4kiB of the DMA window. 2175 2176When the guest issues an H_PUT_TCE hcall on a liobn for which a TCE 2177table has been created using this ioctl(), the kernel will handle it 2178in real mode, updating the TCE table. H_PUT_TCE calls for other 2179liobns will cause a vm exit and must be handled by userspace. 2180 2181The return value is a file descriptor which can be passed to mmap(2) 2182to map the created TCE table into userspace. This lets userspace read 2183the entries written by kernel-handled H_PUT_TCE calls, and also lets 2184userspace update the TCE table directly which is useful in some 2185circumstances. 2186 2187 21884.64 KVM_NMI 2189------------ 2190 2191:Capability: KVM_CAP_USER_NMI 2192:Architectures: x86 2193:Type: vcpu ioctl 2194:Parameters: none 2195:Returns: 0 on success, -1 on error 2196 2197Queues an NMI on the thread's vcpu. Note this is well defined only 2198when KVM_CREATE_IRQCHIP has not been called, since this is an interface 2199between the virtual cpu core and virtual local APIC. After KVM_CREATE_IRQCHIP 2200has been called, this interface is completely emulated within the kernel. 2201 2202To use this to emulate the LINT1 input with KVM_CREATE_IRQCHIP, use the 2203following algorithm: 2204 2205 - pause the vcpu 2206 - read the local APIC's state (KVM_GET_LAPIC) 2207 - check whether changing LINT1 will queue an NMI (see the LVT entry for LINT1) 2208 - if so, issue KVM_NMI 2209 - resume the vcpu 2210 2211Some guests configure the LINT1 NMI input to cause a panic, aiding in 2212debugging. 2213 2214 22154.65 KVM_S390_UCAS_MAP 2216---------------------- 2217 2218:Capability: KVM_CAP_S390_UCONTROL 2219:Architectures: s390 2220:Type: vcpu ioctl 2221:Parameters: struct kvm_s390_ucas_mapping (in) 2222:Returns: 0 in case of success 2223 2224The parameter is defined like this:: 2225 2226 struct kvm_s390_ucas_mapping { 2227 __u64 user_addr; 2228 __u64 vcpu_addr; 2229 __u64 length; 2230 }; 2231 2232This ioctl maps the memory at "user_addr" with the length "length" to 2233the vcpu's address space starting at "vcpu_addr". All parameters need to 2234be aligned by 1 megabyte. 2235 2236 22374.66 KVM_S390_UCAS_UNMAP 2238------------------------ 2239 2240:Capability: KVM_CAP_S390_UCONTROL 2241:Architectures: s390 2242:Type: vcpu ioctl 2243:Parameters: struct kvm_s390_ucas_mapping (in) 2244:Returns: 0 in case of success 2245 2246The parameter is defined like this:: 2247 2248 struct kvm_s390_ucas_mapping { 2249 __u64 user_addr; 2250 __u64 vcpu_addr; 2251 __u64 length; 2252 }; 2253 2254This ioctl unmaps the memory in the vcpu's address space starting at 2255"vcpu_addr" with the length "length". The field "user_addr" is ignored. 2256All parameters need to be aligned by 1 megabyte. 2257 2258 22594.67 KVM_S390_VCPU_FAULT 2260------------------------ 2261 2262:Capability: KVM_CAP_S390_UCONTROL 2263:Architectures: s390 2264:Type: vcpu ioctl 2265:Parameters: vcpu absolute address (in) 2266:Returns: 0 in case of success 2267 2268This call creates a page table entry on the virtual cpu's address space 2269(for user controlled virtual machines) or the virtual machine's address 2270space (for regular virtual machines). This only works for minor faults, 2271thus it's recommended to access subject memory page via the user page 2272table upfront. This is useful to handle validity intercepts for user 2273controlled virtual machines to fault in the virtual cpu's lowcore pages 2274prior to calling the KVM_RUN ioctl. 2275 2276 22774.68 KVM_SET_ONE_REG 2278-------------------- 2279 2280:Capability: KVM_CAP_ONE_REG 2281:Architectures: all 2282:Type: vcpu ioctl 2283:Parameters: struct kvm_one_reg (in) 2284:Returns: 0 on success, negative value on failure 2285 2286Errors: 2287 2288 ====== ============================================================ 2289 ENOENT no such register 2290 EINVAL invalid register ID, or no such register or used with VMs in 2291 protected virtualization mode on s390 2292 EPERM (arm64) register access not allowed before vcpu finalization 2293 EBUSY (riscv) changing register value not allowed after the vcpu 2294 has run at least once 2295 ====== ============================================================ 2296 2297(These error codes are indicative only: do not rely on a specific error 2298code being returned in a specific situation.) 2299 2300:: 2301 2302 struct kvm_one_reg { 2303 __u64 id; 2304 __u64 addr; 2305 }; 2306 2307Using this ioctl, a single vcpu register can be set to a specific value 2308defined by user space with the passed in struct kvm_one_reg, where id 2309refers to the register identifier as described below and addr is a pointer 2310to a variable with the respective size. There can be architecture agnostic 2311and architecture specific registers. Each have their own range of operation 2312and their own constants and width. To keep track of the implemented 2313registers, find a list below: 2314 2315 ======= =============================== ============ 2316 Arch Register Width (bits) 2317 ======= =============================== ============ 2318 PPC KVM_REG_PPC_HIOR 64 2319 PPC KVM_REG_PPC_IAC1 64 2320 PPC KVM_REG_PPC_IAC2 64 2321 PPC KVM_REG_PPC_IAC3 64 2322 PPC KVM_REG_PPC_IAC4 64 2323 PPC KVM_REG_PPC_DAC1 64 2324 PPC KVM_REG_PPC_DAC2 64 2325 PPC KVM_REG_PPC_DABR 64 2326 PPC KVM_REG_PPC_DSCR 64 2327 PPC KVM_REG_PPC_PURR 64 2328 PPC KVM_REG_PPC_SPURR 64 2329 PPC KVM_REG_PPC_DAR 64 2330 PPC KVM_REG_PPC_DSISR 32 2331 PPC KVM_REG_PPC_AMR 64 2332 PPC KVM_REG_PPC_UAMOR 64 2333 PPC KVM_REG_PPC_MMCR0 64 2334 PPC KVM_REG_PPC_MMCR1 64 2335 PPC KVM_REG_PPC_MMCRA 64 2336 PPC KVM_REG_PPC_MMCR2 64 2337 PPC KVM_REG_PPC_MMCRS 64 2338 PPC KVM_REG_PPC_MMCR3 64 2339 PPC KVM_REG_PPC_SIAR 64 2340 PPC KVM_REG_PPC_SDAR 64 2341 PPC KVM_REG_PPC_SIER 64 2342 PPC KVM_REG_PPC_SIER2 64 2343 PPC KVM_REG_PPC_SIER3 64 2344 PPC KVM_REG_PPC_PMC1 32 2345 PPC KVM_REG_PPC_PMC2 32 2346 PPC KVM_REG_PPC_PMC3 32 2347 PPC KVM_REG_PPC_PMC4 32 2348 PPC KVM_REG_PPC_PMC5 32 2349 PPC KVM_REG_PPC_PMC6 32 2350 PPC KVM_REG_PPC_PMC7 32 2351 PPC KVM_REG_PPC_PMC8 32 2352 PPC KVM_REG_PPC_FPR0 64 2353 ... 2354 PPC KVM_REG_PPC_FPR31 64 2355 PPC KVM_REG_PPC_VR0 128 2356 ... 2357 PPC KVM_REG_PPC_VR31 128 2358 PPC KVM_REG_PPC_VSR0 128 2359 ... 2360 PPC KVM_REG_PPC_VSR31 128 2361 PPC KVM_REG_PPC_FPSCR 64 2362 PPC KVM_REG_PPC_VSCR 32 2363 PPC KVM_REG_PPC_VPA_ADDR 64 2364 PPC KVM_REG_PPC_VPA_SLB 128 2365 PPC KVM_REG_PPC_VPA_DTL 128 2366 PPC KVM_REG_PPC_EPCR 32 2367 PPC KVM_REG_PPC_EPR 32 2368 PPC KVM_REG_PPC_TCR 32 2369 PPC KVM_REG_PPC_TSR 32 2370 PPC KVM_REG_PPC_OR_TSR 32 2371 PPC KVM_REG_PPC_CLEAR_TSR 32 2372 PPC KVM_REG_PPC_MAS0 32 2373 PPC KVM_REG_PPC_MAS1 32 2374 PPC KVM_REG_PPC_MAS2 64 2375 PPC KVM_REG_PPC_MAS7_3 64 2376 PPC KVM_REG_PPC_MAS4 32 2377 PPC KVM_REG_PPC_MAS6 32 2378 PPC KVM_REG_PPC_MMUCFG 32 2379 PPC KVM_REG_PPC_TLB0CFG 32 2380 PPC KVM_REG_PPC_TLB1CFG 32 2381 PPC KVM_REG_PPC_TLB2CFG 32 2382 PPC KVM_REG_PPC_TLB3CFG 32 2383 PPC KVM_REG_PPC_TLB0PS 32 2384 PPC KVM_REG_PPC_TLB1PS 32 2385 PPC KVM_REG_PPC_TLB2PS 32 2386 PPC KVM_REG_PPC_TLB3PS 32 2387 PPC KVM_REG_PPC_EPTCFG 32 2388 PPC KVM_REG_PPC_ICP_STATE 64 2389 PPC KVM_REG_PPC_VP_STATE 128 2390 PPC KVM_REG_PPC_TB_OFFSET 64 2391 PPC KVM_REG_PPC_SPMC1 32 2392 PPC KVM_REG_PPC_SPMC2 32 2393 PPC KVM_REG_PPC_IAMR 64 2394 PPC KVM_REG_PPC_TFHAR 64 2395 PPC KVM_REG_PPC_TFIAR 64 2396 PPC KVM_REG_PPC_TEXASR 64 2397 PPC KVM_REG_PPC_FSCR 64 2398 PPC KVM_REG_PPC_PSPB 32 2399 PPC KVM_REG_PPC_EBBHR 64 2400 PPC KVM_REG_PPC_EBBRR 64 2401 PPC KVM_REG_PPC_BESCR 64 2402 PPC KVM_REG_PPC_TAR 64 2403 PPC KVM_REG_PPC_DPDES 64 2404 PPC KVM_REG_PPC_DAWR 64 2405 PPC KVM_REG_PPC_DAWRX 64 2406 PPC KVM_REG_PPC_CIABR 64 2407 PPC KVM_REG_PPC_IC 64 2408 PPC KVM_REG_PPC_VTB 64 2409 PPC KVM_REG_PPC_CSIGR 64 2410 PPC KVM_REG_PPC_TACR 64 2411 PPC KVM_REG_PPC_TCSCR 64 2412 PPC KVM_REG_PPC_PID 64 2413 PPC KVM_REG_PPC_ACOP 64 2414 PPC KVM_REG_PPC_VRSAVE 32 2415 PPC KVM_REG_PPC_LPCR 32 2416 PPC KVM_REG_PPC_LPCR_64 64 2417 PPC KVM_REG_PPC_PPR 64 2418 PPC KVM_REG_PPC_ARCH_COMPAT 32 2419 PPC KVM_REG_PPC_DABRX 32 2420 PPC KVM_REG_PPC_WORT 64 2421 PPC KVM_REG_PPC_SPRG9 64 2422 PPC KVM_REG_PPC_DBSR 32 2423 PPC KVM_REG_PPC_TIDR 64 2424 PPC KVM_REG_PPC_PSSCR 64 2425 PPC KVM_REG_PPC_DEC_EXPIRY 64 2426 PPC KVM_REG_PPC_PTCR 64 2427 PPC KVM_REG_PPC_HASHKEYR 64 2428 PPC KVM_REG_PPC_HASHPKEYR 64 2429 PPC KVM_REG_PPC_DAWR1 64 2430 PPC KVM_REG_PPC_DAWRX1 64 2431 PPC KVM_REG_PPC_DEXCR 64 2432 PPC KVM_REG_PPC_TM_GPR0 64 2433 ... 2434 PPC KVM_REG_PPC_TM_GPR31 64 2435 PPC KVM_REG_PPC_TM_VSR0 128 2436 ... 2437 PPC KVM_REG_PPC_TM_VSR63 128 2438 PPC KVM_REG_PPC_TM_CR 64 2439 PPC KVM_REG_PPC_TM_LR 64 2440 PPC KVM_REG_PPC_TM_CTR 64 2441 PPC KVM_REG_PPC_TM_FPSCR 64 2442 PPC KVM_REG_PPC_TM_AMR 64 2443 PPC KVM_REG_PPC_TM_PPR 64 2444 PPC KVM_REG_PPC_TM_VRSAVE 64 2445 PPC KVM_REG_PPC_TM_VSCR 32 2446 PPC KVM_REG_PPC_TM_DSCR 64 2447 PPC KVM_REG_PPC_TM_TAR 64 2448 PPC KVM_REG_PPC_TM_XER 64 2449 2450 MIPS KVM_REG_MIPS_R0 64 2451 ... 2452 MIPS KVM_REG_MIPS_R31 64 2453 MIPS KVM_REG_MIPS_HI 64 2454 MIPS KVM_REG_MIPS_LO 64 2455 MIPS KVM_REG_MIPS_PC 64 2456 MIPS KVM_REG_MIPS_CP0_INDEX 32 2457 MIPS KVM_REG_MIPS_CP0_ENTRYLO0 64 2458 MIPS KVM_REG_MIPS_CP0_ENTRYLO1 64 2459 MIPS KVM_REG_MIPS_CP0_CONTEXT 64 2460 MIPS KVM_REG_MIPS_CP0_CONTEXTCONFIG 32 2461 MIPS KVM_REG_MIPS_CP0_USERLOCAL 64 2462 MIPS KVM_REG_MIPS_CP0_XCONTEXTCONFIG 64 2463 MIPS KVM_REG_MIPS_CP0_PAGEMASK 32 2464 MIPS KVM_REG_MIPS_CP0_PAGEGRAIN 32 2465 MIPS KVM_REG_MIPS_CP0_SEGCTL0 64 2466 MIPS KVM_REG_MIPS_CP0_SEGCTL1 64 2467 MIPS KVM_REG_MIPS_CP0_SEGCTL2 64 2468 MIPS KVM_REG_MIPS_CP0_PWBASE 64 2469 MIPS KVM_REG_MIPS_CP0_PWFIELD 64 2470 MIPS KVM_REG_MIPS_CP0_PWSIZE 64 2471 MIPS KVM_REG_MIPS_CP0_WIRED 32 2472 MIPS KVM_REG_MIPS_CP0_PWCTL 32 2473 MIPS KVM_REG_MIPS_CP0_HWRENA 32 2474 MIPS KVM_REG_MIPS_CP0_BADVADDR 64 2475 MIPS KVM_REG_MIPS_CP0_BADINSTR 32 2476 MIPS KVM_REG_MIPS_CP0_BADINSTRP 32 2477 MIPS KVM_REG_MIPS_CP0_COUNT 32 2478 MIPS KVM_REG_MIPS_CP0_ENTRYHI 64 2479 MIPS KVM_REG_MIPS_CP0_COMPARE 32 2480 MIPS KVM_REG_MIPS_CP0_STATUS 32 2481 MIPS KVM_REG_MIPS_CP0_INTCTL 32 2482 MIPS KVM_REG_MIPS_CP0_CAUSE 32 2483 MIPS KVM_REG_MIPS_CP0_EPC 64 2484 MIPS KVM_REG_MIPS_CP0_PRID 32 2485 MIPS KVM_REG_MIPS_CP0_EBASE 64 2486 MIPS KVM_REG_MIPS_CP0_CONFIG 32 2487 MIPS KVM_REG_MIPS_CP0_CONFIG1 32 2488 MIPS KVM_REG_MIPS_CP0_CONFIG2 32 2489 MIPS KVM_REG_MIPS_CP0_CONFIG3 32 2490 MIPS KVM_REG_MIPS_CP0_CONFIG4 32 2491 MIPS KVM_REG_MIPS_CP0_CONFIG5 32 2492 MIPS KVM_REG_MIPS_CP0_CONFIG7 32 2493 MIPS KVM_REG_MIPS_CP0_XCONTEXT 64 2494 MIPS KVM_REG_MIPS_CP0_ERROREPC 64 2495 MIPS KVM_REG_MIPS_CP0_KSCRATCH1 64 2496 MIPS KVM_REG_MIPS_CP0_KSCRATCH2 64 2497 MIPS KVM_REG_MIPS_CP0_KSCRATCH3 64 2498 MIPS KVM_REG_MIPS_CP0_KSCRATCH4 64 2499 MIPS KVM_REG_MIPS_CP0_KSCRATCH5 64 2500 MIPS KVM_REG_MIPS_CP0_KSCRATCH6 64 2501 MIPS KVM_REG_MIPS_CP0_MAAR(0..63) 64 2502 MIPS KVM_REG_MIPS_COUNT_CTL 64 2503 MIPS KVM_REG_MIPS_COUNT_RESUME 64 2504 MIPS KVM_REG_MIPS_COUNT_HZ 64 2505 MIPS KVM_REG_MIPS_FPR_32(0..31) 32 2506 MIPS KVM_REG_MIPS_FPR_64(0..31) 64 2507 MIPS KVM_REG_MIPS_VEC_128(0..31) 128 2508 MIPS KVM_REG_MIPS_FCR_IR 32 2509 MIPS KVM_REG_MIPS_FCR_CSR 32 2510 MIPS KVM_REG_MIPS_MSA_IR 32 2511 MIPS KVM_REG_MIPS_MSA_CSR 32 2512 ======= =============================== ============ 2513 2514ARM registers are mapped using the lower 32 bits. The upper 16 of that 2515is the register group type, or coprocessor number: 2516 2517ARM core registers have the following id bit patterns:: 2518 2519 0x4020 0000 0010 <index into the kvm_regs struct:16> 2520 2521ARM 32-bit CP15 registers have the following id bit patterns:: 2522 2523 0x4020 0000 000F <zero:1> <crn:4> <crm:4> <opc1:4> <opc2:3> 2524 2525ARM 64-bit CP15 registers have the following id bit patterns:: 2526 2527 0x4030 0000 000F <zero:1> <zero:4> <crm:4> <opc1:4> <zero:3> 2528 2529ARM CCSIDR registers are demultiplexed by CSSELR value:: 2530 2531 0x4020 0000 0011 00 <csselr:8> 2532 2533ARM 32-bit VFP control registers have the following id bit patterns:: 2534 2535 0x4020 0000 0012 1 <regno:12> 2536 2537ARM 64-bit FP registers have the following id bit patterns:: 2538 2539 0x4030 0000 0012 0 <regno:12> 2540 2541ARM firmware pseudo-registers have the following bit pattern:: 2542 2543 0x4030 0000 0014 <regno:16> 2544 2545 2546arm64 registers are mapped using the lower 32 bits. The upper 16 of 2547that is the register group type, or coprocessor number: 2548 2549arm64 core/FP-SIMD registers have the following id bit patterns. Note 2550that the size of the access is variable, as the kvm_regs structure 2551contains elements ranging from 32 to 128 bits. The index is a 32bit 2552value in the kvm_regs structure seen as a 32bit array:: 2553 2554 0x60x0 0000 0010 <index into the kvm_regs struct:16> 2555 2556Specifically: 2557 2558======================= ========= ===== ======================================= 2559 Encoding Register Bits kvm_regs member 2560======================= ========= ===== ======================================= 2561 0x6030 0000 0010 0000 X0 64 regs.regs[0] 2562 0x6030 0000 0010 0002 X1 64 regs.regs[1] 2563 ... 2564 0x6030 0000 0010 003c X30 64 regs.regs[30] 2565 0x6030 0000 0010 003e SP 64 regs.sp 2566 0x6030 0000 0010 0040 PC 64 regs.pc 2567 0x6030 0000 0010 0042 PSTATE 64 regs.pstate 2568 0x6030 0000 0010 0044 SP_EL1 64 sp_el1 2569 0x6030 0000 0010 0046 ELR_EL1 64 elr_el1 2570 0x6030 0000 0010 0048 SPSR_EL1 64 spsr[KVM_SPSR_EL1] (alias SPSR_SVC) 2571 0x6030 0000 0010 004a SPSR_ABT 64 spsr[KVM_SPSR_ABT] 2572 0x6030 0000 0010 004c SPSR_UND 64 spsr[KVM_SPSR_UND] 2573 0x6030 0000 0010 004e SPSR_IRQ 64 spsr[KVM_SPSR_IRQ] 2574 0x6030 0000 0010 0050 SPSR_FIQ 64 spsr[KVM_SPSR_FIQ] 2575 0x6040 0000 0010 0054 V0 128 fp_regs.vregs[0] [1]_ 2576 0x6040 0000 0010 0058 V1 128 fp_regs.vregs[1] [1]_ 2577 ... 2578 0x6040 0000 0010 00d0 V31 128 fp_regs.vregs[31] [1]_ 2579 0x6020 0000 0010 00d4 FPSR 32 fp_regs.fpsr 2580 0x6020 0000 0010 00d5 FPCR 32 fp_regs.fpcr 2581======================= ========= ===== ======================================= 2582 2583.. [1] These encodings are not accepted for SVE-enabled vcpus. See 2584 :ref:`KVM_ARM_VCPU_INIT`. 2585 2586 The equivalent register content can be accessed via bits [127:0] of 2587 the corresponding SVE Zn registers instead for vcpus that have SVE 2588 enabled (see below). 2589 2590arm64 CCSIDR registers are demultiplexed by CSSELR value:: 2591 2592 0x6020 0000 0011 00 <csselr:8> 2593 2594arm64 system registers have the following id bit patterns:: 2595 2596 0x6030 0000 0013 <op0:2> <op1:3> <crn:4> <crm:4> <op2:3> 2597 2598.. warning:: 2599 2600 Two system register IDs do not follow the specified pattern. These 2601 are KVM_REG_ARM_TIMER_CVAL and KVM_REG_ARM_TIMER_CNT, which map to 2602 system registers CNTV_CVAL_EL0 and CNTVCT_EL0 respectively. These 2603 two had their values accidentally swapped, which means TIMER_CVAL is 2604 derived from the register encoding for CNTVCT_EL0 and TIMER_CNT is 2605 derived from the register encoding for CNTV_CVAL_EL0. As this is 2606 API, it must remain this way. 2607 2608arm64 firmware pseudo-registers have the following bit pattern:: 2609 2610 0x6030 0000 0014 <regno:16> 2611 2612arm64 SVE registers have the following bit patterns:: 2613 2614 0x6080 0000 0015 00 <n:5> <slice:5> Zn bits[2048*slice + 2047 : 2048*slice] 2615 0x6050 0000 0015 04 <n:4> <slice:5> Pn bits[256*slice + 255 : 256*slice] 2616 0x6050 0000 0015 060 <slice:5> FFR bits[256*slice + 255 : 256*slice] 2617 0x6060 0000 0015 ffff KVM_REG_ARM64_SVE_VLS pseudo-register 2618 2619Access to register IDs where 2048 * slice >= 128 * max_vq will fail with 2620ENOENT. max_vq is the vcpu's maximum supported vector length in 128-bit 2621quadwords: see [2]_ below. 2622 2623These registers are only accessible on vcpus for which SVE is enabled. 2624See KVM_ARM_VCPU_INIT for details. 2625 2626In addition, except for KVM_REG_ARM64_SVE_VLS, these registers are not 2627accessible until the vcpu's SVE configuration has been finalized 2628using KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE). See KVM_ARM_VCPU_INIT 2629and KVM_ARM_VCPU_FINALIZE for more information about this procedure. 2630 2631KVM_REG_ARM64_SVE_VLS is a pseudo-register that allows the set of vector 2632lengths supported by the vcpu to be discovered and configured by 2633userspace. When transferred to or from user memory via KVM_GET_ONE_REG 2634or KVM_SET_ONE_REG, the value of this register is of type 2635__u64[KVM_ARM64_SVE_VLS_WORDS], and encodes the set of vector lengths as 2636follows:: 2637 2638 __u64 vector_lengths[KVM_ARM64_SVE_VLS_WORDS]; 2639 2640 if (vq >= SVE_VQ_MIN && vq <= SVE_VQ_MAX && 2641 ((vector_lengths[(vq - KVM_ARM64_SVE_VQ_MIN) / 64] >> 2642 ((vq - KVM_ARM64_SVE_VQ_MIN) % 64)) & 1)) 2643 /* Vector length vq * 16 bytes supported */ 2644 else 2645 /* Vector length vq * 16 bytes not supported */ 2646 2647.. [2] The maximum value vq for which the above condition is true is 2648 max_vq. This is the maximum vector length available to the guest on 2649 this vcpu, and determines which register slices are visible through 2650 this ioctl interface. 2651 2652(See Documentation/arch/arm64/sve.rst for an explanation of the "vq" 2653nomenclature.) 2654 2655KVM_REG_ARM64_SVE_VLS is only accessible after KVM_ARM_VCPU_INIT. 2656KVM_ARM_VCPU_INIT initialises it to the best set of vector lengths that 2657the host supports. 2658 2659Userspace may subsequently modify it if desired until the vcpu's SVE 2660configuration is finalized using KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE). 2661 2662Apart from simply removing all vector lengths from the host set that 2663exceed some value, support for arbitrarily chosen sets of vector lengths 2664is hardware-dependent and may not be available. Attempting to configure 2665an invalid set of vector lengths via KVM_SET_ONE_REG will fail with 2666EINVAL. 2667 2668After the vcpu's SVE configuration is finalized, further attempts to 2669write this register will fail with EPERM. 2670 2671arm64 bitmap feature firmware pseudo-registers have the following bit pattern:: 2672 2673 0x6030 0000 0016 <regno:16> 2674 2675The bitmap feature firmware registers exposes the hypercall services that 2676are available for userspace to configure. The set bits corresponds to the 2677services that are available for the guests to access. By default, KVM 2678sets all the supported bits during VM initialization. The userspace can 2679discover the available services via KVM_GET_ONE_REG, and write back the 2680bitmap corresponding to the features that it wishes guests to see via 2681KVM_SET_ONE_REG. 2682 2683Note: These registers are immutable once any of the vCPUs of the VM has 2684run at least once. A KVM_SET_ONE_REG in such a scenario will return 2685a -EBUSY to userspace. 2686 2687(See Documentation/virt/kvm/arm/hypercalls.rst for more details.) 2688 2689 2690MIPS registers are mapped using the lower 32 bits. The upper 16 of that is 2691the register group type: 2692 2693MIPS core registers (see above) have the following id bit patterns:: 2694 2695 0x7030 0000 0000 <reg:16> 2696 2697MIPS CP0 registers (see KVM_REG_MIPS_CP0_* above) have the following id bit 2698patterns depending on whether they're 32-bit or 64-bit registers:: 2699 2700 0x7020 0000 0001 00 <reg:5> <sel:3> (32-bit) 2701 0x7030 0000 0001 00 <reg:5> <sel:3> (64-bit) 2702 2703Note: KVM_REG_MIPS_CP0_ENTRYLO0 and KVM_REG_MIPS_CP0_ENTRYLO1 are the MIPS64 2704versions of the EntryLo registers regardless of the word size of the host 2705hardware, host kernel, guest, and whether XPA is present in the guest, i.e. 2706with the RI and XI bits (if they exist) in bits 63 and 62 respectively, and 2707the PFNX field starting at bit 30. 2708 2709MIPS MAARs (see KVM_REG_MIPS_CP0_MAAR(*) above) have the following id bit 2710patterns:: 2711 2712 0x7030 0000 0001 01 <reg:8> 2713 2714MIPS KVM control registers (see above) have the following id bit patterns:: 2715 2716 0x7030 0000 0002 <reg:16> 2717 2718MIPS FPU registers (see KVM_REG_MIPS_FPR_{32,64}() above) have the following 2719id bit patterns depending on the size of the register being accessed. They are 2720always accessed according to the current guest FPU mode (Status.FR and 2721Config5.FRE), i.e. as the guest would see them, and they become unpredictable 2722if the guest FPU mode is changed. MIPS SIMD Architecture (MSA) vector 2723registers (see KVM_REG_MIPS_VEC_128() above) have similar patterns as they 2724overlap the FPU registers:: 2725 2726 0x7020 0000 0003 00 <0:3> <reg:5> (32-bit FPU registers) 2727 0x7030 0000 0003 00 <0:3> <reg:5> (64-bit FPU registers) 2728 0x7040 0000 0003 00 <0:3> <reg:5> (128-bit MSA vector registers) 2729 2730MIPS FPU control registers (see KVM_REG_MIPS_FCR_{IR,CSR} above) have the 2731following id bit patterns:: 2732 2733 0x7020 0000 0003 01 <0:3> <reg:5> 2734 2735MIPS MSA control registers (see KVM_REG_MIPS_MSA_{IR,CSR} above) have the 2736following id bit patterns:: 2737 2738 0x7020 0000 0003 02 <0:3> <reg:5> 2739 2740RISC-V registers are mapped using the lower 32 bits. The upper 8 bits of 2741that is the register group type. 2742 2743RISC-V config registers are meant for configuring a Guest VCPU and it has 2744the following id bit patterns:: 2745 2746 0x8020 0000 01 <index into the kvm_riscv_config struct:24> (32bit Host) 2747 0x8030 0000 01 <index into the kvm_riscv_config struct:24> (64bit Host) 2748 2749Following are the RISC-V config registers: 2750 2751======================= ========= ============================================= 2752 Encoding Register Description 2753======================= ========= ============================================= 2754 0x80x0 0000 0100 0000 isa ISA feature bitmap of Guest VCPU 2755======================= ========= ============================================= 2756 2757The isa config register can be read anytime but can only be written before 2758a Guest VCPU runs. It will have ISA feature bits matching underlying host 2759set by default. 2760 2761RISC-V core registers represent the general execution state of a Guest VCPU 2762and it has the following id bit patterns:: 2763 2764 0x8020 0000 02 <index into the kvm_riscv_core struct:24> (32bit Host) 2765 0x8030 0000 02 <index into the kvm_riscv_core struct:24> (64bit Host) 2766 2767Following are the RISC-V core registers: 2768 2769======================= ========= ============================================= 2770 Encoding Register Description 2771======================= ========= ============================================= 2772 0x80x0 0000 0200 0000 regs.pc Program counter 2773 0x80x0 0000 0200 0001 regs.ra Return address 2774 0x80x0 0000 0200 0002 regs.sp Stack pointer 2775 0x80x0 0000 0200 0003 regs.gp Global pointer 2776 0x80x0 0000 0200 0004 regs.tp Task pointer 2777 0x80x0 0000 0200 0005 regs.t0 Caller saved register 0 2778 0x80x0 0000 0200 0006 regs.t1 Caller saved register 1 2779 0x80x0 0000 0200 0007 regs.t2 Caller saved register 2 2780 0x80x0 0000 0200 0008 regs.s0 Callee saved register 0 2781 0x80x0 0000 0200 0009 regs.s1 Callee saved register 1 2782 0x80x0 0000 0200 000a regs.a0 Function argument (or return value) 0 2783 0x80x0 0000 0200 000b regs.a1 Function argument (or return value) 1 2784 0x80x0 0000 0200 000c regs.a2 Function argument 2 2785 0x80x0 0000 0200 000d regs.a3 Function argument 3 2786 0x80x0 0000 0200 000e regs.a4 Function argument 4 2787 0x80x0 0000 0200 000f regs.a5 Function argument 5 2788 0x80x0 0000 0200 0010 regs.a6 Function argument 6 2789 0x80x0 0000 0200 0011 regs.a7 Function argument 7 2790 0x80x0 0000 0200 0012 regs.s2 Callee saved register 2 2791 0x80x0 0000 0200 0013 regs.s3 Callee saved register 3 2792 0x80x0 0000 0200 0014 regs.s4 Callee saved register 4 2793 0x80x0 0000 0200 0015 regs.s5 Callee saved register 5 2794 0x80x0 0000 0200 0016 regs.s6 Callee saved register 6 2795 0x80x0 0000 0200 0017 regs.s7 Callee saved register 7 2796 0x80x0 0000 0200 0018 regs.s8 Callee saved register 8 2797 0x80x0 0000 0200 0019 regs.s9 Callee saved register 9 2798 0x80x0 0000 0200 001a regs.s10 Callee saved register 10 2799 0x80x0 0000 0200 001b regs.s11 Callee saved register 11 2800 0x80x0 0000 0200 001c regs.t3 Caller saved register 3 2801 0x80x0 0000 0200 001d regs.t4 Caller saved register 4 2802 0x80x0 0000 0200 001e regs.t5 Caller saved register 5 2803 0x80x0 0000 0200 001f regs.t6 Caller saved register 6 2804 0x80x0 0000 0200 0020 mode Privilege mode (1 = S-mode or 0 = U-mode) 2805======================= ========= ============================================= 2806 2807RISC-V csr registers represent the supervisor mode control/status registers 2808of a Guest VCPU and it has the following id bit patterns:: 2809 2810 0x8020 0000 03 <index into the kvm_riscv_csr struct:24> (32bit Host) 2811 0x8030 0000 03 <index into the kvm_riscv_csr struct:24> (64bit Host) 2812 2813Following are the RISC-V csr registers: 2814 2815======================= ========= ============================================= 2816 Encoding Register Description 2817======================= ========= ============================================= 2818 0x80x0 0000 0300 0000 sstatus Supervisor status 2819 0x80x0 0000 0300 0001 sie Supervisor interrupt enable 2820 0x80x0 0000 0300 0002 stvec Supervisor trap vector base 2821 0x80x0 0000 0300 0003 sscratch Supervisor scratch register 2822 0x80x0 0000 0300 0004 sepc Supervisor exception program counter 2823 0x80x0 0000 0300 0005 scause Supervisor trap cause 2824 0x80x0 0000 0300 0006 stval Supervisor bad address or instruction 2825 0x80x0 0000 0300 0007 sip Supervisor interrupt pending 2826 0x80x0 0000 0300 0008 satp Supervisor address translation and protection 2827======================= ========= ============================================= 2828 2829RISC-V timer registers represent the timer state of a Guest VCPU and it has 2830the following id bit patterns:: 2831 2832 0x8030 0000 04 <index into the kvm_riscv_timer struct:24> 2833 2834Following are the RISC-V timer registers: 2835 2836======================= ========= ============================================= 2837 Encoding Register Description 2838======================= ========= ============================================= 2839 0x8030 0000 0400 0000 frequency Time base frequency (read-only) 2840 0x8030 0000 0400 0001 time Time value visible to Guest 2841 0x8030 0000 0400 0002 compare Time compare programmed by Guest 2842 0x8030 0000 0400 0003 state Time compare state (1 = ON or 0 = OFF) 2843======================= ========= ============================================= 2844 2845RISC-V F-extension registers represent the single precision floating point 2846state of a Guest VCPU and it has the following id bit patterns:: 2847 2848 0x8020 0000 05 <index into the __riscv_f_ext_state struct:24> 2849 2850Following are the RISC-V F-extension registers: 2851 2852======================= ========= ============================================= 2853 Encoding Register Description 2854======================= ========= ============================================= 2855 0x8020 0000 0500 0000 f[0] Floating point register 0 2856 ... 2857 0x8020 0000 0500 001f f[31] Floating point register 31 2858 0x8020 0000 0500 0020 fcsr Floating point control and status register 2859======================= ========= ============================================= 2860 2861RISC-V D-extension registers represent the double precision floating point 2862state of a Guest VCPU and it has the following id bit patterns:: 2863 2864 0x8020 0000 06 <index into the __riscv_d_ext_state struct:24> (fcsr) 2865 0x8030 0000 06 <index into the __riscv_d_ext_state struct:24> (non-fcsr) 2866 2867Following are the RISC-V D-extension registers: 2868 2869======================= ========= ============================================= 2870 Encoding Register Description 2871======================= ========= ============================================= 2872 0x8030 0000 0600 0000 f[0] Floating point register 0 2873 ... 2874 0x8030 0000 0600 001f f[31] Floating point register 31 2875 0x8020 0000 0600 0020 fcsr Floating point control and status register 2876======================= ========= ============================================= 2877 2878LoongArch registers are mapped using the lower 32 bits. The upper 16 bits of 2879that is the register group type. 2880 2881LoongArch csr registers are used to control guest cpu or get status of guest 2882cpu, and they have the following id bit patterns:: 2883 2884 0x9030 0000 0001 00 <reg:5> <sel:3> (64-bit) 2885 2886LoongArch KVM control registers are used to implement some new defined functions 2887such as set vcpu counter or reset vcpu, and they have the following id bit patterns:: 2888 2889 0x9030 0000 0002 <reg:16> 2890 2891 28924.69 KVM_GET_ONE_REG 2893-------------------- 2894 2895:Capability: KVM_CAP_ONE_REG 2896:Architectures: all 2897:Type: vcpu ioctl 2898:Parameters: struct kvm_one_reg (in and out) 2899:Returns: 0 on success, negative value on failure 2900 2901Errors include: 2902 2903 ======== ============================================================ 2904 ENOENT no such register 2905 EINVAL invalid register ID, or no such register or used with VMs in 2906 protected virtualization mode on s390 2907 EPERM (arm64) register access not allowed before vcpu finalization 2908 ======== ============================================================ 2909 2910(These error codes are indicative only: do not rely on a specific error 2911code being returned in a specific situation.) 2912 2913This ioctl allows to receive the value of a single register implemented 2914in a vcpu. The register to read is indicated by the "id" field of the 2915kvm_one_reg struct passed in. On success, the register value can be found 2916at the memory location pointed to by "addr". 2917 2918The list of registers accessible using this interface is identical to the 2919list in 4.68. 2920 2921 29224.70 KVM_KVMCLOCK_CTRL 2923---------------------- 2924 2925:Capability: KVM_CAP_KVMCLOCK_CTRL 2926:Architectures: Any that implement pvclocks (currently x86 only) 2927:Type: vcpu ioctl 2928:Parameters: None 2929:Returns: 0 on success, -1 on error 2930 2931This ioctl sets a flag accessible to the guest indicating that the specified 2932vCPU has been paused by the host userspace. 2933 2934The host will set a flag in the pvclock structure that is checked from the 2935soft lockup watchdog. The flag is part of the pvclock structure that is 2936shared between guest and host, specifically the second bit of the flags 2937field of the pvclock_vcpu_time_info structure. It will be set exclusively by 2938the host and read/cleared exclusively by the guest. The guest operation of 2939checking and clearing the flag must be an atomic operation so 2940load-link/store-conditional, or equivalent must be used. There are two cases 2941where the guest will clear the flag: when the soft lockup watchdog timer resets 2942itself or when a soft lockup is detected. This ioctl can be called any time 2943after pausing the vcpu, but before it is resumed. 2944 2945 29464.71 KVM_SIGNAL_MSI 2947------------------- 2948 2949:Capability: KVM_CAP_SIGNAL_MSI 2950:Architectures: x86 arm64 2951:Type: vm ioctl 2952:Parameters: struct kvm_msi (in) 2953:Returns: >0 on delivery, 0 if guest blocked the MSI, and -1 on error 2954 2955Directly inject a MSI message. Only valid with in-kernel irqchip that handles 2956MSI messages. 2957 2958:: 2959 2960 struct kvm_msi { 2961 __u32 address_lo; 2962 __u32 address_hi; 2963 __u32 data; 2964 __u32 flags; 2965 __u32 devid; 2966 __u8 pad[12]; 2967 }; 2968 2969flags: 2970 KVM_MSI_VALID_DEVID: devid contains a valid value. The per-VM 2971 KVM_CAP_MSI_DEVID capability advertises the requirement to provide 2972 the device ID. If this capability is not available, userspace 2973 should never set the KVM_MSI_VALID_DEVID flag as the ioctl might fail. 2974 2975If KVM_MSI_VALID_DEVID is set, devid contains a unique device identifier 2976for the device that wrote the MSI message. For PCI, this is usually a 2977BDF identifier in the lower 16 bits. 2978 2979On x86, address_hi is ignored unless the KVM_X2APIC_API_USE_32BIT_IDS 2980feature of KVM_CAP_X2APIC_API capability is enabled. If it is enabled, 2981address_hi bits 31-8 provide bits 31-8 of the destination id. Bits 7-0 of 2982address_hi must be zero. 2983 2984 29854.71 KVM_CREATE_PIT2 2986-------------------- 2987 2988:Capability: KVM_CAP_PIT2 2989:Architectures: x86 2990:Type: vm ioctl 2991:Parameters: struct kvm_pit_config (in) 2992:Returns: 0 on success, -1 on error 2993 2994Creates an in-kernel device model for the i8254 PIT. This call is only valid 2995after enabling in-kernel irqchip support via KVM_CREATE_IRQCHIP. The following 2996parameters have to be passed:: 2997 2998 struct kvm_pit_config { 2999 __u32 flags; 3000 __u32 pad[15]; 3001 }; 3002 3003Valid flags are:: 3004 3005 #define KVM_PIT_SPEAKER_DUMMY 1 /* emulate speaker port stub */ 3006 3007PIT timer interrupts may use a per-VM kernel thread for injection. If it 3008exists, this thread will have a name of the following pattern:: 3009 3010 kvm-pit/<owner-process-pid> 3011 3012When running a guest with elevated priorities, the scheduling parameters of 3013this thread may have to be adjusted accordingly. 3014 3015This IOCTL replaces the obsolete KVM_CREATE_PIT. 3016 3017 30184.72 KVM_GET_PIT2 3019----------------- 3020 3021:Capability: KVM_CAP_PIT_STATE2 3022:Architectures: x86 3023:Type: vm ioctl 3024:Parameters: struct kvm_pit_state2 (out) 3025:Returns: 0 on success, -1 on error 3026 3027Retrieves the state of the in-kernel PIT model. Only valid after 3028KVM_CREATE_PIT2. The state is returned in the following structure:: 3029 3030 struct kvm_pit_state2 { 3031 struct kvm_pit_channel_state channels[3]; 3032 __u32 flags; 3033 __u32 reserved[9]; 3034 }; 3035 3036Valid flags are:: 3037 3038 /* disable PIT in HPET legacy mode */ 3039 #define KVM_PIT_FLAGS_HPET_LEGACY 0x00000001 3040 /* speaker port data bit enabled */ 3041 #define KVM_PIT_FLAGS_SPEAKER_DATA_ON 0x00000002 3042 3043This IOCTL replaces the obsolete KVM_GET_PIT. 3044 3045 30464.73 KVM_SET_PIT2 3047----------------- 3048 3049:Capability: KVM_CAP_PIT_STATE2 3050:Architectures: x86 3051:Type: vm ioctl 3052:Parameters: struct kvm_pit_state2 (in) 3053:Returns: 0 on success, -1 on error 3054 3055Sets the state of the in-kernel PIT model. Only valid after KVM_CREATE_PIT2. 3056See KVM_GET_PIT2 for details on struct kvm_pit_state2. 3057 3058This IOCTL replaces the obsolete KVM_SET_PIT. 3059 3060 30614.74 KVM_PPC_GET_SMMU_INFO 3062-------------------------- 3063 3064:Capability: KVM_CAP_PPC_GET_SMMU_INFO 3065:Architectures: powerpc 3066:Type: vm ioctl 3067:Parameters: None 3068:Returns: 0 on success, -1 on error 3069 3070This populates and returns a structure describing the features of 3071the "Server" class MMU emulation supported by KVM. 3072This can in turn be used by userspace to generate the appropriate 3073device-tree properties for the guest operating system. 3074 3075The structure contains some global information, followed by an 3076array of supported segment page sizes:: 3077 3078 struct kvm_ppc_smmu_info { 3079 __u64 flags; 3080 __u32 slb_size; 3081 __u32 pad; 3082 struct kvm_ppc_one_seg_page_size sps[KVM_PPC_PAGE_SIZES_MAX_SZ]; 3083 }; 3084 3085The supported flags are: 3086 3087 - KVM_PPC_PAGE_SIZES_REAL: 3088 When that flag is set, guest page sizes must "fit" the backing 3089 store page sizes. When not set, any page size in the list can 3090 be used regardless of how they are backed by userspace. 3091 3092 - KVM_PPC_1T_SEGMENTS 3093 The emulated MMU supports 1T segments in addition to the 3094 standard 256M ones. 3095 3096 - KVM_PPC_NO_HASH 3097 This flag indicates that HPT guests are not supported by KVM, 3098 thus all guests must use radix MMU mode. 3099 3100The "slb_size" field indicates how many SLB entries are supported 3101 3102The "sps" array contains 8 entries indicating the supported base 3103page sizes for a segment in increasing order. Each entry is defined 3104as follow:: 3105 3106 struct kvm_ppc_one_seg_page_size { 3107 __u32 page_shift; /* Base page shift of segment (or 0) */ 3108 __u32 slb_enc; /* SLB encoding for BookS */ 3109 struct kvm_ppc_one_page_size enc[KVM_PPC_PAGE_SIZES_MAX_SZ]; 3110 }; 3111 3112An entry with a "page_shift" of 0 is unused. Because the array is 3113organized in increasing order, a lookup can stop when encountering 3114such an entry. 3115 3116The "slb_enc" field provides the encoding to use in the SLB for the 3117page size. The bits are in positions such as the value can directly 3118be OR'ed into the "vsid" argument of the slbmte instruction. 3119 3120The "enc" array is a list which for each of those segment base page 3121size provides the list of supported actual page sizes (which can be 3122only larger or equal to the base page size), along with the 3123corresponding encoding in the hash PTE. Similarly, the array is 31248 entries sorted by increasing sizes and an entry with a "0" shift 3125is an empty entry and a terminator:: 3126 3127 struct kvm_ppc_one_page_size { 3128 __u32 page_shift; /* Page shift (or 0) */ 3129 __u32 pte_enc; /* Encoding in the HPTE (>>12) */ 3130 }; 3131 3132The "pte_enc" field provides a value that can OR'ed into the hash 3133PTE's RPN field (ie, it needs to be shifted left by 12 to OR it 3134into the hash PTE second double word). 3135 31364.75 KVM_IRQFD 3137-------------- 3138 3139:Capability: KVM_CAP_IRQFD 3140:Architectures: x86 s390 arm64 3141:Type: vm ioctl 3142:Parameters: struct kvm_irqfd (in) 3143:Returns: 0 on success, -1 on error 3144 3145Allows setting an eventfd to directly trigger a guest interrupt. 3146kvm_irqfd.fd specifies the file descriptor to use as the eventfd and 3147kvm_irqfd.gsi specifies the irqchip pin toggled by this event. When 3148an event is triggered on the eventfd, an interrupt is injected into 3149the guest using the specified gsi pin. The irqfd is removed using 3150the KVM_IRQFD_FLAG_DEASSIGN flag, specifying both kvm_irqfd.fd 3151and kvm_irqfd.gsi. 3152 3153With KVM_CAP_IRQFD_RESAMPLE, KVM_IRQFD supports a de-assert and notify 3154mechanism allowing emulation of level-triggered, irqfd-based 3155interrupts. When KVM_IRQFD_FLAG_RESAMPLE is set the user must pass an 3156additional eventfd in the kvm_irqfd.resamplefd field. When operating 3157in resample mode, posting of an interrupt through kvm_irq.fd asserts 3158the specified gsi in the irqchip. When the irqchip is resampled, such 3159as from an EOI, the gsi is de-asserted and the user is notified via 3160kvm_irqfd.resamplefd. It is the user's responsibility to re-queue 3161the interrupt if the device making use of it still requires service. 3162Note that closing the resamplefd is not sufficient to disable the 3163irqfd. The KVM_IRQFD_FLAG_RESAMPLE is only necessary on assignment 3164and need not be specified with KVM_IRQFD_FLAG_DEASSIGN. 3165 3166On arm64, gsi routing being supported, the following can happen: 3167 3168- in case no routing entry is associated to this gsi, injection fails 3169- in case the gsi is associated to an irqchip routing entry, 3170 irqchip.pin + 32 corresponds to the injected SPI ID. 3171- in case the gsi is associated to an MSI routing entry, the MSI 3172 message and device ID are translated into an LPI (support restricted 3173 to GICv3 ITS in-kernel emulation). 3174 31754.76 KVM_PPC_ALLOCATE_HTAB 3176-------------------------- 3177 3178:Capability: KVM_CAP_PPC_ALLOC_HTAB 3179:Architectures: powerpc 3180:Type: vm ioctl 3181:Parameters: Pointer to u32 containing hash table order (in/out) 3182:Returns: 0 on success, -1 on error 3183 3184This requests the host kernel to allocate an MMU hash table for a 3185guest using the PAPR paravirtualization interface. This only does 3186anything if the kernel is configured to use the Book 3S HV style of 3187virtualization. Otherwise the capability doesn't exist and the ioctl 3188returns an ENOTTY error. The rest of this description assumes Book 3S 3189HV. 3190 3191There must be no vcpus running when this ioctl is called; if there 3192are, it will do nothing and return an EBUSY error. 3193 3194The parameter is a pointer to a 32-bit unsigned integer variable 3195containing the order (log base 2) of the desired size of the hash 3196table, which must be between 18 and 46. On successful return from the 3197ioctl, the value will not be changed by the kernel. 3198 3199If no hash table has been allocated when any vcpu is asked to run 3200(with the KVM_RUN ioctl), the host kernel will allocate a 3201default-sized hash table (16 MB). 3202 3203If this ioctl is called when a hash table has already been allocated, 3204with a different order from the existing hash table, the existing hash 3205table will be freed and a new one allocated. If this is ioctl is 3206called when a hash table has already been allocated of the same order 3207as specified, the kernel will clear out the existing hash table (zero 3208all HPTEs). In either case, if the guest is using the virtualized 3209real-mode area (VRMA) facility, the kernel will re-create the VMRA 3210HPTEs on the next KVM_RUN of any vcpu. 3211 32124.77 KVM_S390_INTERRUPT 3213----------------------- 3214 3215:Capability: basic 3216:Architectures: s390 3217:Type: vm ioctl, vcpu ioctl 3218:Parameters: struct kvm_s390_interrupt (in) 3219:Returns: 0 on success, -1 on error 3220 3221Allows to inject an interrupt to the guest. Interrupts can be floating 3222(vm ioctl) or per cpu (vcpu ioctl), depending on the interrupt type. 3223 3224Interrupt parameters are passed via kvm_s390_interrupt:: 3225 3226 struct kvm_s390_interrupt { 3227 __u32 type; 3228 __u32 parm; 3229 __u64 parm64; 3230 }; 3231 3232type can be one of the following: 3233 3234KVM_S390_SIGP_STOP (vcpu) 3235 - sigp stop; optional flags in parm 3236KVM_S390_PROGRAM_INT (vcpu) 3237 - program check; code in parm 3238KVM_S390_SIGP_SET_PREFIX (vcpu) 3239 - sigp set prefix; prefix address in parm 3240KVM_S390_RESTART (vcpu) 3241 - restart 3242KVM_S390_INT_CLOCK_COMP (vcpu) 3243 - clock comparator interrupt 3244KVM_S390_INT_CPU_TIMER (vcpu) 3245 - CPU timer interrupt 3246KVM_S390_INT_VIRTIO (vm) 3247 - virtio external interrupt; external interrupt 3248 parameters in parm and parm64 3249KVM_S390_INT_SERVICE (vm) 3250 - sclp external interrupt; sclp parameter in parm 3251KVM_S390_INT_EMERGENCY (vcpu) 3252 - sigp emergency; source cpu in parm 3253KVM_S390_INT_EXTERNAL_CALL (vcpu) 3254 - sigp external call; source cpu in parm 3255KVM_S390_INT_IO(ai,cssid,ssid,schid) (vm) 3256 - compound value to indicate an 3257 I/O interrupt (ai - adapter interrupt; cssid,ssid,schid - subchannel); 3258 I/O interruption parameters in parm (subchannel) and parm64 (intparm, 3259 interruption subclass) 3260KVM_S390_MCHK (vm, vcpu) 3261 - machine check interrupt; cr 14 bits in parm, machine check interrupt 3262 code in parm64 (note that machine checks needing further payload are not 3263 supported by this ioctl) 3264 3265This is an asynchronous vcpu ioctl and can be invoked from any thread. 3266 32674.78 KVM_PPC_GET_HTAB_FD 3268------------------------ 3269 3270:Capability: KVM_CAP_PPC_HTAB_FD 3271:Architectures: powerpc 3272:Type: vm ioctl 3273:Parameters: Pointer to struct kvm_get_htab_fd (in) 3274:Returns: file descriptor number (>= 0) on success, -1 on error 3275 3276This returns a file descriptor that can be used either to read out the 3277entries in the guest's hashed page table (HPT), or to write entries to 3278initialize the HPT. The returned fd can only be written to if the 3279KVM_GET_HTAB_WRITE bit is set in the flags field of the argument, and 3280can only be read if that bit is clear. The argument struct looks like 3281this:: 3282 3283 /* For KVM_PPC_GET_HTAB_FD */ 3284 struct kvm_get_htab_fd { 3285 __u64 flags; 3286 __u64 start_index; 3287 __u64 reserved[2]; 3288 }; 3289 3290 /* Values for kvm_get_htab_fd.flags */ 3291 #define KVM_GET_HTAB_BOLTED_ONLY ((__u64)0x1) 3292 #define KVM_GET_HTAB_WRITE ((__u64)0x2) 3293 3294The 'start_index' field gives the index in the HPT of the entry at 3295which to start reading. It is ignored when writing. 3296 3297Reads on the fd will initially supply information about all 3298"interesting" HPT entries. Interesting entries are those with the 3299bolted bit set, if the KVM_GET_HTAB_BOLTED_ONLY bit is set, otherwise 3300all entries. When the end of the HPT is reached, the read() will 3301return. If read() is called again on the fd, it will start again from 3302the beginning of the HPT, but will only return HPT entries that have 3303changed since they were last read. 3304 3305Data read or written is structured as a header (8 bytes) followed by a 3306series of valid HPT entries (16 bytes) each. The header indicates how 3307many valid HPT entries there are and how many invalid entries follow 3308the valid entries. The invalid entries are not represented explicitly 3309in the stream. The header format is:: 3310 3311 struct kvm_get_htab_header { 3312 __u32 index; 3313 __u16 n_valid; 3314 __u16 n_invalid; 3315 }; 3316 3317Writes to the fd create HPT entries starting at the index given in the 3318header; first 'n_valid' valid entries with contents from the data 3319written, then 'n_invalid' invalid entries, invalidating any previously 3320valid entries found. 3321 33224.79 KVM_CREATE_DEVICE 3323---------------------- 3324 3325:Capability: KVM_CAP_DEVICE_CTRL 3326:Architectures: all 3327:Type: vm ioctl 3328:Parameters: struct kvm_create_device (in/out) 3329:Returns: 0 on success, -1 on error 3330 3331Errors: 3332 3333 ====== ======================================================= 3334 ENODEV The device type is unknown or unsupported 3335 EEXIST Device already created, and this type of device may not 3336 be instantiated multiple times 3337 ====== ======================================================= 3338 3339 Other error conditions may be defined by individual device types or 3340 have their standard meanings. 3341 3342Creates an emulated device in the kernel. The file descriptor returned 3343in fd can be used with KVM_SET/GET/HAS_DEVICE_ATTR. 3344 3345If the KVM_CREATE_DEVICE_TEST flag is set, only test whether the 3346device type is supported (not necessarily whether it can be created 3347in the current vm). 3348 3349Individual devices should not define flags. Attributes should be used 3350for specifying any behavior that is not implied by the device type 3351number. 3352 3353:: 3354 3355 struct kvm_create_device { 3356 __u32 type; /* in: KVM_DEV_TYPE_xxx */ 3357 __u32 fd; /* out: device handle */ 3358 __u32 flags; /* in: KVM_CREATE_DEVICE_xxx */ 3359 }; 3360 33614.80 KVM_SET_DEVICE_ATTR/KVM_GET_DEVICE_ATTR 3362-------------------------------------------- 3363 3364:Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device, 3365 KVM_CAP_VCPU_ATTRIBUTES for vcpu device 3366 KVM_CAP_SYS_ATTRIBUTES for system (/dev/kvm) device (no set) 3367:Architectures: x86, arm64, s390 3368:Type: device ioctl, vm ioctl, vcpu ioctl 3369:Parameters: struct kvm_device_attr 3370:Returns: 0 on success, -1 on error 3371 3372Errors: 3373 3374 ===== ============================================================= 3375 ENXIO The group or attribute is unknown/unsupported for this device 3376 or hardware support is missing. 3377 EPERM The attribute cannot (currently) be accessed this way 3378 (e.g. read-only attribute, or attribute that only makes 3379 sense when the device is in a different state) 3380 ===== ============================================================= 3381 3382 Other error conditions may be defined by individual device types. 3383 3384Gets/sets a specified piece of device configuration and/or state. The 3385semantics are device-specific. See individual device documentation in 3386the "devices" directory. As with ONE_REG, the size of the data 3387transferred is defined by the particular attribute. 3388 3389:: 3390 3391 struct kvm_device_attr { 3392 __u32 flags; /* no flags currently defined */ 3393 __u32 group; /* device-defined */ 3394 __u64 attr; /* group-defined */ 3395 __u64 addr; /* userspace address of attr data */ 3396 }; 3397 33984.81 KVM_HAS_DEVICE_ATTR 3399------------------------ 3400 3401:Capability: KVM_CAP_DEVICE_CTRL, KVM_CAP_VM_ATTRIBUTES for vm device, 3402 KVM_CAP_VCPU_ATTRIBUTES for vcpu device 3403 KVM_CAP_SYS_ATTRIBUTES for system (/dev/kvm) device 3404:Type: device ioctl, vm ioctl, vcpu ioctl 3405:Parameters: struct kvm_device_attr 3406:Returns: 0 on success, -1 on error 3407 3408Errors: 3409 3410 ===== ============================================================= 3411 ENXIO The group or attribute is unknown/unsupported for this device 3412 or hardware support is missing. 3413 ===== ============================================================= 3414 3415Tests whether a device supports a particular attribute. A successful 3416return indicates the attribute is implemented. It does not necessarily 3417indicate that the attribute can be read or written in the device's 3418current state. "addr" is ignored. 3419 3420.. _KVM_ARM_VCPU_INIT: 3421 34224.82 KVM_ARM_VCPU_INIT 3423---------------------- 3424 3425:Capability: basic 3426:Architectures: arm64 3427:Type: vcpu ioctl 3428:Parameters: struct kvm_vcpu_init (in) 3429:Returns: 0 on success; -1 on error 3430 3431Errors: 3432 3433 ====== ================================================================= 3434 EINVAL the target is unknown, or the combination of features is invalid. 3435 ENOENT a features bit specified is unknown. 3436 ====== ================================================================= 3437 3438This tells KVM what type of CPU to present to the guest, and what 3439optional features it should have. This will cause a reset of the cpu 3440registers to their initial values. If this is not called, KVM_RUN will 3441return ENOEXEC for that vcpu. 3442 3443The initial values are defined as: 3444 - Processor state: 3445 * AArch64: EL1h, D, A, I and F bits set. All other bits 3446 are cleared. 3447 * AArch32: SVC, A, I and F bits set. All other bits are 3448 cleared. 3449 - General Purpose registers, including PC and SP: set to 0 3450 - FPSIMD/NEON registers: set to 0 3451 - SVE registers: set to 0 3452 - System registers: Reset to their architecturally defined 3453 values as for a warm reset to EL1 (resp. SVC) 3454 3455Note that because some registers reflect machine topology, all vcpus 3456should be created before this ioctl is invoked. 3457 3458Userspace can call this function multiple times for a given vcpu, including 3459after the vcpu has been run. This will reset the vcpu to its initial 3460state. All calls to this function after the initial call must use the same 3461target and same set of feature flags, otherwise EINVAL will be returned. 3462 3463Possible features: 3464 3465 - KVM_ARM_VCPU_POWER_OFF: Starts the CPU in a power-off state. 3466 Depends on KVM_CAP_ARM_PSCI. If not set, the CPU will be powered on 3467 and execute guest code when KVM_RUN is called. 3468 - KVM_ARM_VCPU_EL1_32BIT: Starts the CPU in a 32bit mode. 3469 Depends on KVM_CAP_ARM_EL1_32BIT (arm64 only). 3470 - KVM_ARM_VCPU_PSCI_0_2: Emulate PSCI v0.2 (or a future revision 3471 backward compatible with v0.2) for the CPU. 3472 Depends on KVM_CAP_ARM_PSCI_0_2. 3473 - KVM_ARM_VCPU_PMU_V3: Emulate PMUv3 for the CPU. 3474 Depends on KVM_CAP_ARM_PMU_V3. 3475 3476 - KVM_ARM_VCPU_PTRAUTH_ADDRESS: Enables Address Pointer authentication 3477 for arm64 only. 3478 Depends on KVM_CAP_ARM_PTRAUTH_ADDRESS. 3479 If KVM_CAP_ARM_PTRAUTH_ADDRESS and KVM_CAP_ARM_PTRAUTH_GENERIC are 3480 both present, then both KVM_ARM_VCPU_PTRAUTH_ADDRESS and 3481 KVM_ARM_VCPU_PTRAUTH_GENERIC must be requested or neither must be 3482 requested. 3483 3484 - KVM_ARM_VCPU_PTRAUTH_GENERIC: Enables Generic Pointer authentication 3485 for arm64 only. 3486 Depends on KVM_CAP_ARM_PTRAUTH_GENERIC. 3487 If KVM_CAP_ARM_PTRAUTH_ADDRESS and KVM_CAP_ARM_PTRAUTH_GENERIC are 3488 both present, then both KVM_ARM_VCPU_PTRAUTH_ADDRESS and 3489 KVM_ARM_VCPU_PTRAUTH_GENERIC must be requested or neither must be 3490 requested. 3491 3492 - KVM_ARM_VCPU_SVE: Enables SVE for the CPU (arm64 only). 3493 Depends on KVM_CAP_ARM_SVE. 3494 Requires KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): 3495 3496 * After KVM_ARM_VCPU_INIT: 3497 3498 - KVM_REG_ARM64_SVE_VLS may be read using KVM_GET_ONE_REG: the 3499 initial value of this pseudo-register indicates the best set of 3500 vector lengths possible for a vcpu on this host. 3501 3502 * Before KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): 3503 3504 - KVM_RUN and KVM_GET_REG_LIST are not available; 3505 3506 - KVM_GET_ONE_REG and KVM_SET_ONE_REG cannot be used to access 3507 the scalable architectural SVE registers 3508 KVM_REG_ARM64_SVE_ZREG(), KVM_REG_ARM64_SVE_PREG() or 3509 KVM_REG_ARM64_SVE_FFR; 3510 3511 - KVM_REG_ARM64_SVE_VLS may optionally be written using 3512 KVM_SET_ONE_REG, to modify the set of vector lengths available 3513 for the vcpu. 3514 3515 * After KVM_ARM_VCPU_FINALIZE(KVM_ARM_VCPU_SVE): 3516 3517 - the KVM_REG_ARM64_SVE_VLS pseudo-register is immutable, and can 3518 no longer be written using KVM_SET_ONE_REG. 3519 35204.83 KVM_ARM_PREFERRED_TARGET 3521----------------------------- 3522 3523:Capability: basic 3524:Architectures: arm64 3525:Type: vm ioctl 3526:Parameters: struct kvm_vcpu_init (out) 3527:Returns: 0 on success; -1 on error 3528 3529Errors: 3530 3531 ====== ========================================== 3532 ENODEV no preferred target available for the host 3533 ====== ========================================== 3534 3535This queries KVM for preferred CPU target type which can be emulated 3536by KVM on underlying host. 3537 3538The ioctl returns struct kvm_vcpu_init instance containing information 3539about preferred CPU target type and recommended features for it. The 3540kvm_vcpu_init->features bitmap returned will have feature bits set if 3541the preferred target recommends setting these features, but this is 3542not mandatory. 3543 3544The information returned by this ioctl can be used to prepare an instance 3545of struct kvm_vcpu_init for KVM_ARM_VCPU_INIT ioctl which will result in 3546VCPU matching underlying host. 3547 3548 35494.84 KVM_GET_REG_LIST 3550--------------------- 3551 3552:Capability: basic 3553:Architectures: arm64, mips, riscv 3554:Type: vcpu ioctl 3555:Parameters: struct kvm_reg_list (in/out) 3556:Returns: 0 on success; -1 on error 3557 3558Errors: 3559 3560 ===== ============================================================== 3561 E2BIG the reg index list is too big to fit in the array specified by 3562 the user (the number required will be written into n). 3563 ===== ============================================================== 3564 3565:: 3566 3567 struct kvm_reg_list { 3568 __u64 n; /* number of registers in reg[] */ 3569 __u64 reg[0]; 3570 }; 3571 3572This ioctl returns the guest registers that are supported for the 3573KVM_GET_ONE_REG/KVM_SET_ONE_REG calls. 3574 3575Note that s390 does not support KVM_GET_REG_LIST for historical reasons 3576(read: nobody cared). The set of registers in kernels 4.x and newer is: 3577 3578- KVM_REG_S390_TODPR 3579 3580- KVM_REG_S390_EPOCHDIFF 3581 3582- KVM_REG_S390_CPU_TIMER 3583 3584- KVM_REG_S390_CLOCK_COMP 3585 3586- KVM_REG_S390_PFTOKEN 3587 3588- KVM_REG_S390_PFCOMPARE 3589 3590- KVM_REG_S390_PFSELECT 3591 3592- KVM_REG_S390_PP 3593 3594- KVM_REG_S390_GBEA 3595 3596 35974.85 KVM_ARM_SET_DEVICE_ADDR (deprecated) 3598----------------------------------------- 3599 3600:Capability: KVM_CAP_ARM_SET_DEVICE_ADDR 3601:Architectures: arm64 3602:Type: vm ioctl 3603:Parameters: struct kvm_arm_device_address (in) 3604:Returns: 0 on success, -1 on error 3605 3606Errors: 3607 3608 ====== ============================================ 3609 ENODEV The device id is unknown 3610 ENXIO Device not supported on current system 3611 EEXIST Address already set 3612 E2BIG Address outside guest physical address space 3613 EBUSY Address overlaps with other device range 3614 ====== ============================================ 3615 3616:: 3617 3618 struct kvm_arm_device_addr { 3619 __u64 id; 3620 __u64 addr; 3621 }; 3622 3623Specify a device address in the guest's physical address space where guests 3624can access emulated or directly exposed devices, which the host kernel needs 3625to know about. The id field is an architecture specific identifier for a 3626specific device. 3627 3628arm64 divides the id field into two parts, a device id and an 3629address type id specific to the individual device:: 3630 3631 bits: | 63 ... 32 | 31 ... 16 | 15 ... 0 | 3632 field: | 0x00000000 | device id | addr type id | 3633 3634arm64 currently only require this when using the in-kernel GIC 3635support for the hardware VGIC features, using KVM_ARM_DEVICE_VGIC_V2 3636as the device id. When setting the base address for the guest's 3637mapping of the VGIC virtual CPU and distributor interface, the ioctl 3638must be called after calling KVM_CREATE_IRQCHIP, but before calling 3639KVM_RUN on any of the VCPUs. Calling this ioctl twice for any of the 3640base addresses will return -EEXIST. 3641 3642Note, this IOCTL is deprecated and the more flexible SET/GET_DEVICE_ATTR API 3643should be used instead. 3644 3645 36464.86 KVM_PPC_RTAS_DEFINE_TOKEN 3647------------------------------ 3648 3649:Capability: KVM_CAP_PPC_RTAS 3650:Architectures: ppc 3651:Type: vm ioctl 3652:Parameters: struct kvm_rtas_token_args 3653:Returns: 0 on success, -1 on error 3654 3655Defines a token value for a RTAS (Run Time Abstraction Services) 3656service in order to allow it to be handled in the kernel. The 3657argument struct gives the name of the service, which must be the name 3658of a service that has a kernel-side implementation. If the token 3659value is non-zero, it will be associated with that service, and 3660subsequent RTAS calls by the guest specifying that token will be 3661handled by the kernel. If the token value is 0, then any token 3662associated with the service will be forgotten, and subsequent RTAS 3663calls by the guest for that service will be passed to userspace to be 3664handled. 3665 36664.87 KVM_SET_GUEST_DEBUG 3667------------------------ 3668 3669:Capability: KVM_CAP_SET_GUEST_DEBUG 3670:Architectures: x86, s390, ppc, arm64 3671:Type: vcpu ioctl 3672:Parameters: struct kvm_guest_debug (in) 3673:Returns: 0 on success; -1 on error 3674 3675:: 3676 3677 struct kvm_guest_debug { 3678 __u32 control; 3679 __u32 pad; 3680 struct kvm_guest_debug_arch arch; 3681 }; 3682 3683Set up the processor specific debug registers and configure vcpu for 3684handling guest debug events. There are two parts to the structure, the 3685first a control bitfield indicates the type of debug events to handle 3686when running. Common control bits are: 3687 3688 - KVM_GUESTDBG_ENABLE: guest debugging is enabled 3689 - KVM_GUESTDBG_SINGLESTEP: the next run should single-step 3690 3691The top 16 bits of the control field are architecture specific control 3692flags which can include the following: 3693 3694 - KVM_GUESTDBG_USE_SW_BP: using software breakpoints [x86, arm64] 3695 - KVM_GUESTDBG_USE_HW_BP: using hardware breakpoints [x86, s390] 3696 - KVM_GUESTDBG_USE_HW: using hardware debug events [arm64] 3697 - KVM_GUESTDBG_INJECT_DB: inject DB type exception [x86] 3698 - KVM_GUESTDBG_INJECT_BP: inject BP type exception [x86] 3699 - KVM_GUESTDBG_EXIT_PENDING: trigger an immediate guest exit [s390] 3700 - KVM_GUESTDBG_BLOCKIRQ: avoid injecting interrupts/NMI/SMI [x86] 3701 3702For example KVM_GUESTDBG_USE_SW_BP indicates that software breakpoints 3703are enabled in memory so we need to ensure breakpoint exceptions are 3704correctly trapped and the KVM run loop exits at the breakpoint and not 3705running off into the normal guest vector. For KVM_GUESTDBG_USE_HW_BP 3706we need to ensure the guest vCPUs architecture specific registers are 3707updated to the correct (supplied) values. 3708 3709The second part of the structure is architecture specific and 3710typically contains a set of debug registers. 3711 3712For arm64 the number of debug registers is implementation defined and 3713can be determined by querying the KVM_CAP_GUEST_DEBUG_HW_BPS and 3714KVM_CAP_GUEST_DEBUG_HW_WPS capabilities which return a positive number 3715indicating the number of supported registers. 3716 3717For ppc, the KVM_CAP_PPC_GUEST_DEBUG_SSTEP capability indicates whether 3718the single-step debug event (KVM_GUESTDBG_SINGLESTEP) is supported. 3719 3720Also when supported, KVM_CAP_SET_GUEST_DEBUG2 capability indicates the 3721supported KVM_GUESTDBG_* bits in the control field. 3722 3723When debug events exit the main run loop with the reason 3724KVM_EXIT_DEBUG with the kvm_debug_exit_arch part of the kvm_run 3725structure containing architecture specific debug information. 3726 37274.88 KVM_GET_EMULATED_CPUID 3728--------------------------- 3729 3730:Capability: KVM_CAP_EXT_EMUL_CPUID 3731:Architectures: x86 3732:Type: system ioctl 3733:Parameters: struct kvm_cpuid2 (in/out) 3734:Returns: 0 on success, -1 on error 3735 3736:: 3737 3738 struct kvm_cpuid2 { 3739 __u32 nent; 3740 __u32 flags; 3741 struct kvm_cpuid_entry2 entries[0]; 3742 }; 3743 3744The member 'flags' is used for passing flags from userspace. 3745 3746:: 3747 3748 #define KVM_CPUID_FLAG_SIGNIFCANT_INDEX BIT(0) 3749 #define KVM_CPUID_FLAG_STATEFUL_FUNC BIT(1) /* deprecated */ 3750 #define KVM_CPUID_FLAG_STATE_READ_NEXT BIT(2) /* deprecated */ 3751 3752 struct kvm_cpuid_entry2 { 3753 __u32 function; 3754 __u32 index; 3755 __u32 flags; 3756 __u32 eax; 3757 __u32 ebx; 3758 __u32 ecx; 3759 __u32 edx; 3760 __u32 padding[3]; 3761 }; 3762 3763This ioctl returns x86 cpuid features which are emulated by 3764kvm.Userspace can use the information returned by this ioctl to query 3765which features are emulated by kvm instead of being present natively. 3766 3767Userspace invokes KVM_GET_EMULATED_CPUID by passing a kvm_cpuid2 3768structure with the 'nent' field indicating the number of entries in 3769the variable-size array 'entries'. If the number of entries is too low 3770to describe the cpu capabilities, an error (E2BIG) is returned. If the 3771number is too high, the 'nent' field is adjusted and an error (ENOMEM) 3772is returned. If the number is just right, the 'nent' field is adjusted 3773to the number of valid entries in the 'entries' array, which is then 3774filled. 3775 3776The entries returned are the set CPUID bits of the respective features 3777which kvm emulates, as returned by the CPUID instruction, with unknown 3778or unsupported feature bits cleared. 3779 3780Features like x2apic, for example, may not be present in the host cpu 3781but are exposed by kvm in KVM_GET_SUPPORTED_CPUID because they can be 3782emulated efficiently and thus not included here. 3783 3784The fields in each entry are defined as follows: 3785 3786 function: 3787 the eax value used to obtain the entry 3788 index: 3789 the ecx value used to obtain the entry (for entries that are 3790 affected by ecx) 3791 flags: 3792 an OR of zero or more of the following: 3793 3794 KVM_CPUID_FLAG_SIGNIFCANT_INDEX: 3795 if the index field is valid 3796 3797 eax, ebx, ecx, edx: 3798 3799 the values returned by the cpuid instruction for 3800 this function/index combination 3801 38024.89 KVM_S390_MEM_OP 3803-------------------- 3804 3805:Capability: KVM_CAP_S390_MEM_OP, KVM_CAP_S390_PROTECTED, KVM_CAP_S390_MEM_OP_EXTENSION 3806:Architectures: s390 3807:Type: vm ioctl, vcpu ioctl 3808:Parameters: struct kvm_s390_mem_op (in) 3809:Returns: = 0 on success, 3810 < 0 on generic error (e.g. -EFAULT or -ENOMEM), 3811 16 bit program exception code if the access causes such an exception 3812 3813Read or write data from/to the VM's memory. 3814The KVM_CAP_S390_MEM_OP_EXTENSION capability specifies what functionality is 3815supported. 3816 3817Parameters are specified via the following structure:: 3818 3819 struct kvm_s390_mem_op { 3820 __u64 gaddr; /* the guest address */ 3821 __u64 flags; /* flags */ 3822 __u32 size; /* amount of bytes */ 3823 __u32 op; /* type of operation */ 3824 __u64 buf; /* buffer in userspace */ 3825 union { 3826 struct { 3827 __u8 ar; /* the access register number */ 3828 __u8 key; /* access key, ignored if flag unset */ 3829 __u8 pad1[6]; /* ignored */ 3830 __u64 old_addr; /* ignored if flag unset */ 3831 }; 3832 __u32 sida_offset; /* offset into the sida */ 3833 __u8 reserved[32]; /* ignored */ 3834 }; 3835 }; 3836 3837The start address of the memory region has to be specified in the "gaddr" 3838field, and the length of the region in the "size" field (which must not 3839be 0). The maximum value for "size" can be obtained by checking the 3840KVM_CAP_S390_MEM_OP capability. "buf" is the buffer supplied by the 3841userspace application where the read data should be written to for 3842a read access, or where the data that should be written is stored for 3843a write access. The "reserved" field is meant for future extensions. 3844Reserved and unused values are ignored. Future extension that add members must 3845introduce new flags. 3846 3847The type of operation is specified in the "op" field. Flags modifying 3848their behavior can be set in the "flags" field. Undefined flag bits must 3849be set to 0. 3850 3851Possible operations are: 3852 * ``KVM_S390_MEMOP_LOGICAL_READ`` 3853 * ``KVM_S390_MEMOP_LOGICAL_WRITE`` 3854 * ``KVM_S390_MEMOP_ABSOLUTE_READ`` 3855 * ``KVM_S390_MEMOP_ABSOLUTE_WRITE`` 3856 * ``KVM_S390_MEMOP_SIDA_READ`` 3857 * ``KVM_S390_MEMOP_SIDA_WRITE`` 3858 * ``KVM_S390_MEMOP_ABSOLUTE_CMPXCHG`` 3859 3860Logical read/write: 3861^^^^^^^^^^^^^^^^^^^ 3862 3863Access logical memory, i.e. translate the given guest address to an absolute 3864address given the state of the VCPU and use the absolute address as target of 3865the access. "ar" designates the access register number to be used; the valid 3866range is 0..15. 3867Logical accesses are permitted for the VCPU ioctl only. 3868Logical accesses are permitted for non-protected guests only. 3869 3870Supported flags: 3871 * ``KVM_S390_MEMOP_F_CHECK_ONLY`` 3872 * ``KVM_S390_MEMOP_F_INJECT_EXCEPTION`` 3873 * ``KVM_S390_MEMOP_F_SKEY_PROTECTION`` 3874 3875The KVM_S390_MEMOP_F_CHECK_ONLY flag can be set to check whether the 3876corresponding memory access would cause an access exception; however, 3877no actual access to the data in memory at the destination is performed. 3878In this case, "buf" is unused and can be NULL. 3879 3880In case an access exception occurred during the access (or would occur 3881in case of KVM_S390_MEMOP_F_CHECK_ONLY), the ioctl returns a positive 3882error number indicating the type of exception. This exception is also 3883raised directly at the corresponding VCPU if the flag 3884KVM_S390_MEMOP_F_INJECT_EXCEPTION is set. 3885On protection exceptions, unless specified otherwise, the injected 3886translation-exception identifier (TEID) indicates suppression. 3887 3888If the KVM_S390_MEMOP_F_SKEY_PROTECTION flag is set, storage key 3889protection is also in effect and may cause exceptions if accesses are 3890prohibited given the access key designated by "key"; the valid range is 0..15. 3891KVM_S390_MEMOP_F_SKEY_PROTECTION is available if KVM_CAP_S390_MEM_OP_EXTENSION 3892is > 0. 3893Since the accessed memory may span multiple pages and those pages might have 3894different storage keys, it is possible that a protection exception occurs 3895after memory has been modified. In this case, if the exception is injected, 3896the TEID does not indicate suppression. 3897 3898Absolute read/write: 3899^^^^^^^^^^^^^^^^^^^^ 3900 3901Access absolute memory. This operation is intended to be used with the 3902KVM_S390_MEMOP_F_SKEY_PROTECTION flag, to allow accessing memory and performing 3903the checks required for storage key protection as one operation (as opposed to 3904user space getting the storage keys, performing the checks, and accessing 3905memory thereafter, which could lead to a delay between check and access). 3906Absolute accesses are permitted for the VM ioctl if KVM_CAP_S390_MEM_OP_EXTENSION 3907has the KVM_S390_MEMOP_EXTENSION_CAP_BASE bit set. 3908Currently absolute accesses are not permitted for VCPU ioctls. 3909Absolute accesses are permitted for non-protected guests only. 3910 3911Supported flags: 3912 * ``KVM_S390_MEMOP_F_CHECK_ONLY`` 3913 * ``KVM_S390_MEMOP_F_SKEY_PROTECTION`` 3914 3915The semantics of the flags common with logical accesses are as for logical 3916accesses. 3917 3918Absolute cmpxchg: 3919^^^^^^^^^^^^^^^^^ 3920 3921Perform cmpxchg on absolute guest memory. Intended for use with the 3922KVM_S390_MEMOP_F_SKEY_PROTECTION flag. 3923Instead of doing an unconditional write, the access occurs only if the target 3924location contains the value pointed to by "old_addr". 3925This is performed as an atomic cmpxchg with the length specified by the "size" 3926parameter. "size" must be a power of two up to and including 16. 3927If the exchange did not take place because the target value doesn't match the 3928old value, the value "old_addr" points to is replaced by the target value. 3929User space can tell if an exchange took place by checking if this replacement 3930occurred. The cmpxchg op is permitted for the VM ioctl if 3931KVM_CAP_S390_MEM_OP_EXTENSION has flag KVM_S390_MEMOP_EXTENSION_CAP_CMPXCHG set. 3932 3933Supported flags: 3934 * ``KVM_S390_MEMOP_F_SKEY_PROTECTION`` 3935 3936SIDA read/write: 3937^^^^^^^^^^^^^^^^ 3938 3939Access the secure instruction data area which contains memory operands necessary 3940for instruction emulation for protected guests. 3941SIDA accesses are available if the KVM_CAP_S390_PROTECTED capability is available. 3942SIDA accesses are permitted for the VCPU ioctl only. 3943SIDA accesses are permitted for protected guests only. 3944 3945No flags are supported. 3946 39474.90 KVM_S390_GET_SKEYS 3948----------------------- 3949 3950:Capability: KVM_CAP_S390_SKEYS 3951:Architectures: s390 3952:Type: vm ioctl 3953:Parameters: struct kvm_s390_skeys 3954:Returns: 0 on success, KVM_S390_GET_SKEYS_NONE if guest is not using storage 3955 keys, negative value on error 3956 3957This ioctl is used to get guest storage key values on the s390 3958architecture. The ioctl takes parameters via the kvm_s390_skeys struct:: 3959 3960 struct kvm_s390_skeys { 3961 __u64 start_gfn; 3962 __u64 count; 3963 __u64 skeydata_addr; 3964 __u32 flags; 3965 __u32 reserved[9]; 3966 }; 3967 3968The start_gfn field is the number of the first guest frame whose storage keys 3969you want to get. 3970 3971The count field is the number of consecutive frames (starting from start_gfn) 3972whose storage keys to get. The count field must be at least 1 and the maximum 3973allowed value is defined as KVM_S390_SKEYS_MAX. Values outside this range 3974will cause the ioctl to return -EINVAL. 3975 3976The skeydata_addr field is the address to a buffer large enough to hold count 3977bytes. This buffer will be filled with storage key data by the ioctl. 3978 39794.91 KVM_S390_SET_SKEYS 3980----------------------- 3981 3982:Capability: KVM_CAP_S390_SKEYS 3983:Architectures: s390 3984:Type: vm ioctl 3985:Parameters: struct kvm_s390_skeys 3986:Returns: 0 on success, negative value on error 3987 3988This ioctl is used to set guest storage key values on the s390 3989architecture. The ioctl takes parameters via the kvm_s390_skeys struct. 3990See section on KVM_S390_GET_SKEYS for struct definition. 3991 3992The start_gfn field is the number of the first guest frame whose storage keys 3993you want to set. 3994 3995The count field is the number of consecutive frames (starting from start_gfn) 3996whose storage keys to get. The count field must be at least 1 and the maximum 3997allowed value is defined as KVM_S390_SKEYS_MAX. Values outside this range 3998will cause the ioctl to return -EINVAL. 3999 4000The skeydata_addr field is the address to a buffer containing count bytes of 4001storage keys. Each byte in the buffer will be set as the storage key for a 4002single frame starting at start_gfn for count frames. 4003 4004Note: If any architecturally invalid key value is found in the given data then 4005the ioctl will return -EINVAL. 4006 40074.92 KVM_S390_IRQ 4008----------------- 4009 4010:Capability: KVM_CAP_S390_INJECT_IRQ 4011:Architectures: s390 4012:Type: vcpu ioctl 4013:Parameters: struct kvm_s390_irq (in) 4014:Returns: 0 on success, -1 on error 4015 4016Errors: 4017 4018 4019 ====== ================================================================= 4020 EINVAL interrupt type is invalid 4021 type is KVM_S390_SIGP_STOP and flag parameter is invalid value, 4022 type is KVM_S390_INT_EXTERNAL_CALL and code is bigger 4023 than the maximum of VCPUs 4024 EBUSY type is KVM_S390_SIGP_SET_PREFIX and vcpu is not stopped, 4025 type is KVM_S390_SIGP_STOP and a stop irq is already pending, 4026 type is KVM_S390_INT_EXTERNAL_CALL and an external call interrupt 4027 is already pending 4028 ====== ================================================================= 4029 4030Allows to inject an interrupt to the guest. 4031 4032Using struct kvm_s390_irq as a parameter allows 4033to inject additional payload which is not 4034possible via KVM_S390_INTERRUPT. 4035 4036Interrupt parameters are passed via kvm_s390_irq:: 4037 4038 struct kvm_s390_irq { 4039 __u64 type; 4040 union { 4041 struct kvm_s390_io_info io; 4042 struct kvm_s390_ext_info ext; 4043 struct kvm_s390_pgm_info pgm; 4044 struct kvm_s390_emerg_info emerg; 4045 struct kvm_s390_extcall_info extcall; 4046 struct kvm_s390_prefix_info prefix; 4047 struct kvm_s390_stop_info stop; 4048 struct kvm_s390_mchk_info mchk; 4049 char reserved[64]; 4050 } u; 4051 }; 4052 4053type can be one of the following: 4054 4055- KVM_S390_SIGP_STOP - sigp stop; parameter in .stop 4056- KVM_S390_PROGRAM_INT - program check; parameters in .pgm 4057- KVM_S390_SIGP_SET_PREFIX - sigp set prefix; parameters in .prefix 4058- KVM_S390_RESTART - restart; no parameters 4059- KVM_S390_INT_CLOCK_COMP - clock comparator interrupt; no parameters 4060- KVM_S390_INT_CPU_TIMER - CPU timer interrupt; no parameters 4061- KVM_S390_INT_EMERGENCY - sigp emergency; parameters in .emerg 4062- KVM_S390_INT_EXTERNAL_CALL - sigp external call; parameters in .extcall 4063- KVM_S390_MCHK - machine check interrupt; parameters in .mchk 4064 4065This is an asynchronous vcpu ioctl and can be invoked from any thread. 4066 40674.94 KVM_S390_GET_IRQ_STATE 4068--------------------------- 4069 4070:Capability: KVM_CAP_S390_IRQ_STATE 4071:Architectures: s390 4072:Type: vcpu ioctl 4073:Parameters: struct kvm_s390_irq_state (out) 4074:Returns: >= number of bytes copied into buffer, 4075 -EINVAL if buffer size is 0, 4076 -ENOBUFS if buffer size is too small to fit all pending interrupts, 4077 -EFAULT if the buffer address was invalid 4078 4079This ioctl allows userspace to retrieve the complete state of all currently 4080pending interrupts in a single buffer. Use cases include migration 4081and introspection. The parameter structure contains the address of a 4082userspace buffer and its length:: 4083 4084 struct kvm_s390_irq_state { 4085 __u64 buf; 4086 __u32 flags; /* will stay unused for compatibility reasons */ 4087 __u32 len; 4088 __u32 reserved[4]; /* will stay unused for compatibility reasons */ 4089 }; 4090 4091Userspace passes in the above struct and for each pending interrupt a 4092struct kvm_s390_irq is copied to the provided buffer. 4093 4094The structure contains a flags and a reserved field for future extensions. As 4095the kernel never checked for flags == 0 and QEMU never pre-zeroed flags and 4096reserved, these fields can not be used in the future without breaking 4097compatibility. 4098 4099If -ENOBUFS is returned the buffer provided was too small and userspace 4100may retry with a bigger buffer. 4101 41024.95 KVM_S390_SET_IRQ_STATE 4103--------------------------- 4104 4105:Capability: KVM_CAP_S390_IRQ_STATE 4106:Architectures: s390 4107:Type: vcpu ioctl 4108:Parameters: struct kvm_s390_irq_state (in) 4109:Returns: 0 on success, 4110 -EFAULT if the buffer address was invalid, 4111 -EINVAL for an invalid buffer length (see below), 4112 -EBUSY if there were already interrupts pending, 4113 errors occurring when actually injecting the 4114 interrupt. See KVM_S390_IRQ. 4115 4116This ioctl allows userspace to set the complete state of all cpu-local 4117interrupts currently pending for the vcpu. It is intended for restoring 4118interrupt state after a migration. The input parameter is a userspace buffer 4119containing a struct kvm_s390_irq_state:: 4120 4121 struct kvm_s390_irq_state { 4122 __u64 buf; 4123 __u32 flags; /* will stay unused for compatibility reasons */ 4124 __u32 len; 4125 __u32 reserved[4]; /* will stay unused for compatibility reasons */ 4126 }; 4127 4128The restrictions for flags and reserved apply as well. 4129(see KVM_S390_GET_IRQ_STATE) 4130 4131The userspace memory referenced by buf contains a struct kvm_s390_irq 4132for each interrupt to be injected into the guest. 4133If one of the interrupts could not be injected for some reason the 4134ioctl aborts. 4135 4136len must be a multiple of sizeof(struct kvm_s390_irq). It must be > 0 4137and it must not exceed (max_vcpus + 32) * sizeof(struct kvm_s390_irq), 4138which is the maximum number of possibly pending cpu-local interrupts. 4139 41404.96 KVM_SMI 4141------------ 4142 4143:Capability: KVM_CAP_X86_SMM 4144:Architectures: x86 4145:Type: vcpu ioctl 4146:Parameters: none 4147:Returns: 0 on success, -1 on error 4148 4149Queues an SMI on the thread's vcpu. 4150 41514.97 KVM_X86_SET_MSR_FILTER 4152---------------------------- 4153 4154:Capability: KVM_CAP_X86_MSR_FILTER 4155:Architectures: x86 4156:Type: vm ioctl 4157:Parameters: struct kvm_msr_filter 4158:Returns: 0 on success, < 0 on error 4159 4160:: 4161 4162 struct kvm_msr_filter_range { 4163 #define KVM_MSR_FILTER_READ (1 << 0) 4164 #define KVM_MSR_FILTER_WRITE (1 << 1) 4165 __u32 flags; 4166 __u32 nmsrs; /* number of msrs in bitmap */ 4167 __u32 base; /* MSR index the bitmap starts at */ 4168 __u8 *bitmap; /* a 1 bit allows the operations in flags, 0 denies */ 4169 }; 4170 4171 #define KVM_MSR_FILTER_MAX_RANGES 16 4172 struct kvm_msr_filter { 4173 #define KVM_MSR_FILTER_DEFAULT_ALLOW (0 << 0) 4174 #define KVM_MSR_FILTER_DEFAULT_DENY (1 << 0) 4175 __u32 flags; 4176 struct kvm_msr_filter_range ranges[KVM_MSR_FILTER_MAX_RANGES]; 4177 }; 4178 4179flags values for ``struct kvm_msr_filter_range``: 4180 4181``KVM_MSR_FILTER_READ`` 4182 4183 Filter read accesses to MSRs using the given bitmap. A 0 in the bitmap 4184 indicates that read accesses should be denied, while a 1 indicates that 4185 a read for a particular MSR should be allowed regardless of the default 4186 filter action. 4187 4188``KVM_MSR_FILTER_WRITE`` 4189 4190 Filter write accesses to MSRs using the given bitmap. A 0 in the bitmap 4191 indicates that write accesses should be denied, while a 1 indicates that 4192 a write for a particular MSR should be allowed regardless of the default 4193 filter action. 4194 4195flags values for ``struct kvm_msr_filter``: 4196 4197``KVM_MSR_FILTER_DEFAULT_ALLOW`` 4198 4199 If no filter range matches an MSR index that is getting accessed, KVM will 4200 allow accesses to all MSRs by default. 4201 4202``KVM_MSR_FILTER_DEFAULT_DENY`` 4203 4204 If no filter range matches an MSR index that is getting accessed, KVM will 4205 deny accesses to all MSRs by default. 4206 4207This ioctl allows userspace to define up to 16 bitmaps of MSR ranges to deny 4208guest MSR accesses that would normally be allowed by KVM. If an MSR is not 4209covered by a specific range, the "default" filtering behavior applies. Each 4210bitmap range covers MSRs from [base .. base+nmsrs). 4211 4212If an MSR access is denied by userspace, the resulting KVM behavior depends on 4213whether or not KVM_CAP_X86_USER_SPACE_MSR's KVM_MSR_EXIT_REASON_FILTER is 4214enabled. If KVM_MSR_EXIT_REASON_FILTER is enabled, KVM will exit to userspace 4215on denied accesses, i.e. userspace effectively intercepts the MSR access. If 4216KVM_MSR_EXIT_REASON_FILTER is not enabled, KVM will inject a #GP into the guest 4217on denied accesses. Note, if an MSR access is denied during emulation of MSR 4218load/stores during VMX transitions, KVM ignores KVM_MSR_EXIT_REASON_FILTER. 4219See the below warning for full details. 4220 4221If an MSR access is allowed by userspace, KVM will emulate and/or virtualize 4222the access in accordance with the vCPU model. Note, KVM may still ultimately 4223inject a #GP if an access is allowed by userspace, e.g. if KVM doesn't support 4224the MSR, or to follow architectural behavior for the MSR. 4225 4226By default, KVM operates in KVM_MSR_FILTER_DEFAULT_ALLOW mode with no MSR range 4227filters. 4228 4229Calling this ioctl with an empty set of ranges (all nmsrs == 0) disables MSR 4230filtering. In that mode, ``KVM_MSR_FILTER_DEFAULT_DENY`` is invalid and causes 4231an error. 4232 4233.. warning:: 4234 MSR accesses that are side effects of instruction execution (emulated or 4235 native) are not filtered as hardware does not honor MSR bitmaps outside of 4236 RDMSR and WRMSR, and KVM mimics that behavior when emulating instructions 4237 to avoid pointless divergence from hardware. E.g. RDPID reads MSR_TSC_AUX, 4238 SYSENTER reads the SYSENTER MSRs, etc. 4239 4240 MSRs that are loaded/stored via dedicated VMCS fields are not filtered as 4241 part of VM-Enter/VM-Exit emulation. 4242 4243 MSRs that are loaded/store via VMX's load/store lists _are_ filtered as part 4244 of VM-Enter/VM-Exit emulation. If an MSR access is denied on VM-Enter, KVM 4245 synthesizes a consistency check VM-Exit(EXIT_REASON_MSR_LOAD_FAIL). If an 4246 MSR access is denied on VM-Exit, KVM synthesizes a VM-Abort. In short, KVM 4247 extends Intel's architectural list of MSRs that cannot be loaded/saved via 4248 the VM-Enter/VM-Exit MSR list. It is platform owner's responsibility to 4249 to communicate any such restrictions to their end users. 4250 4251 x2APIC MSR accesses cannot be filtered (KVM silently ignores filters that 4252 cover any x2APIC MSRs). 4253 4254Note, invoking this ioctl while a vCPU is running is inherently racy. However, 4255KVM does guarantee that vCPUs will see either the previous filter or the new 4256filter, e.g. MSRs with identical settings in both the old and new filter will 4257have deterministic behavior. 4258 4259Similarly, if userspace wishes to intercept on denied accesses, 4260KVM_MSR_EXIT_REASON_FILTER must be enabled before activating any filters, and 4261left enabled until after all filters are deactivated. Failure to do so may 4262result in KVM injecting a #GP instead of exiting to userspace. 4263 42644.98 KVM_CREATE_SPAPR_TCE_64 4265---------------------------- 4266 4267:Capability: KVM_CAP_SPAPR_TCE_64 4268:Architectures: powerpc 4269:Type: vm ioctl 4270:Parameters: struct kvm_create_spapr_tce_64 (in) 4271:Returns: file descriptor for manipulating the created TCE table 4272 4273This is an extension for KVM_CAP_SPAPR_TCE which only supports 32bit 4274windows, described in 4.62 KVM_CREATE_SPAPR_TCE 4275 4276This capability uses extended struct in ioctl interface:: 4277 4278 /* for KVM_CAP_SPAPR_TCE_64 */ 4279 struct kvm_create_spapr_tce_64 { 4280 __u64 liobn; 4281 __u32 page_shift; 4282 __u32 flags; 4283 __u64 offset; /* in pages */ 4284 __u64 size; /* in pages */ 4285 }; 4286 4287The aim of extension is to support an additional bigger DMA window with 4288a variable page size. 4289KVM_CREATE_SPAPR_TCE_64 receives a 64bit window size, an IOMMU page shift and 4290a bus offset of the corresponding DMA window, @size and @offset are numbers 4291of IOMMU pages. 4292 4293@flags are not used at the moment. 4294 4295The rest of functionality is identical to KVM_CREATE_SPAPR_TCE. 4296 42974.99 KVM_REINJECT_CONTROL 4298------------------------- 4299 4300:Capability: KVM_CAP_REINJECT_CONTROL 4301:Architectures: x86 4302:Type: vm ioctl 4303:Parameters: struct kvm_reinject_control (in) 4304:Returns: 0 on success, 4305 -EFAULT if struct kvm_reinject_control cannot be read, 4306 -ENXIO if KVM_CREATE_PIT or KVM_CREATE_PIT2 didn't succeed earlier. 4307 4308i8254 (PIT) has two modes, reinject and !reinject. The default is reinject, 4309where KVM queues elapsed i8254 ticks and monitors completion of interrupt from 4310vector(s) that i8254 injects. Reinject mode dequeues a tick and injects its 4311interrupt whenever there isn't a pending interrupt from i8254. 4312!reinject mode injects an interrupt as soon as a tick arrives. 4313 4314:: 4315 4316 struct kvm_reinject_control { 4317 __u8 pit_reinject; 4318 __u8 reserved[31]; 4319 }; 4320 4321pit_reinject = 0 (!reinject mode) is recommended, unless running an old 4322operating system that uses the PIT for timing (e.g. Linux 2.4.x). 4323 43244.100 KVM_PPC_CONFIGURE_V3_MMU 4325------------------------------ 4326 4327:Capability: KVM_CAP_PPC_MMU_RADIX or KVM_CAP_PPC_MMU_HASH_V3 4328:Architectures: ppc 4329:Type: vm ioctl 4330:Parameters: struct kvm_ppc_mmuv3_cfg (in) 4331:Returns: 0 on success, 4332 -EFAULT if struct kvm_ppc_mmuv3_cfg cannot be read, 4333 -EINVAL if the configuration is invalid 4334 4335This ioctl controls whether the guest will use radix or HPT (hashed 4336page table) translation, and sets the pointer to the process table for 4337the guest. 4338 4339:: 4340 4341 struct kvm_ppc_mmuv3_cfg { 4342 __u64 flags; 4343 __u64 process_table; 4344 }; 4345 4346There are two bits that can be set in flags; KVM_PPC_MMUV3_RADIX and 4347KVM_PPC_MMUV3_GTSE. KVM_PPC_MMUV3_RADIX, if set, configures the guest 4348to use radix tree translation, and if clear, to use HPT translation. 4349KVM_PPC_MMUV3_GTSE, if set and if KVM permits it, configures the guest 4350to be able to use the global TLB and SLB invalidation instructions; 4351if clear, the guest may not use these instructions. 4352 4353The process_table field specifies the address and size of the guest 4354process table, which is in the guest's space. This field is formatted 4355as the second doubleword of the partition table entry, as defined in 4356the Power ISA V3.00, Book III section 5.7.6.1. 4357 43584.101 KVM_PPC_GET_RMMU_INFO 4359--------------------------- 4360 4361:Capability: KVM_CAP_PPC_MMU_RADIX 4362:Architectures: ppc 4363:Type: vm ioctl 4364:Parameters: struct kvm_ppc_rmmu_info (out) 4365:Returns: 0 on success, 4366 -EFAULT if struct kvm_ppc_rmmu_info cannot be written, 4367 -EINVAL if no useful information can be returned 4368 4369This ioctl returns a structure containing two things: (a) a list 4370containing supported radix tree geometries, and (b) a list that maps 4371page sizes to put in the "AP" (actual page size) field for the tlbie 4372(TLB invalidate entry) instruction. 4373 4374:: 4375 4376 struct kvm_ppc_rmmu_info { 4377 struct kvm_ppc_radix_geom { 4378 __u8 page_shift; 4379 __u8 level_bits[4]; 4380 __u8 pad[3]; 4381 } geometries[8]; 4382 __u32 ap_encodings[8]; 4383 }; 4384 4385The geometries[] field gives up to 8 supported geometries for the 4386radix page table, in terms of the log base 2 of the smallest page 4387size, and the number of bits indexed at each level of the tree, from 4388the PTE level up to the PGD level in that order. Any unused entries 4389will have 0 in the page_shift field. 4390 4391The ap_encodings gives the supported page sizes and their AP field 4392encodings, encoded with the AP value in the top 3 bits and the log 4393base 2 of the page size in the bottom 6 bits. 4394 43954.102 KVM_PPC_RESIZE_HPT_PREPARE 4396-------------------------------- 4397 4398:Capability: KVM_CAP_SPAPR_RESIZE_HPT 4399:Architectures: powerpc 4400:Type: vm ioctl 4401:Parameters: struct kvm_ppc_resize_hpt (in) 4402:Returns: 0 on successful completion, 4403 >0 if a new HPT is being prepared, the value is an estimated 4404 number of milliseconds until preparation is complete, 4405 -EFAULT if struct kvm_reinject_control cannot be read, 4406 -EINVAL if the supplied shift or flags are invalid, 4407 -ENOMEM if unable to allocate the new HPT, 4408 4409Used to implement the PAPR extension for runtime resizing of a guest's 4410Hashed Page Table (HPT). Specifically this starts, stops or monitors 4411the preparation of a new potential HPT for the guest, essentially 4412implementing the H_RESIZE_HPT_PREPARE hypercall. 4413 4414:: 4415 4416 struct kvm_ppc_resize_hpt { 4417 __u64 flags; 4418 __u32 shift; 4419 __u32 pad; 4420 }; 4421 4422If called with shift > 0 when there is no pending HPT for the guest, 4423this begins preparation of a new pending HPT of size 2^(shift) bytes. 4424It then returns a positive integer with the estimated number of 4425milliseconds until preparation is complete. 4426 4427If called when there is a pending HPT whose size does not match that 4428requested in the parameters, discards the existing pending HPT and 4429creates a new one as above. 4430 4431If called when there is a pending HPT of the size requested, will: 4432 4433 * If preparation of the pending HPT is already complete, return 0 4434 * If preparation of the pending HPT has failed, return an error 4435 code, then discard the pending HPT. 4436 * If preparation of the pending HPT is still in progress, return an 4437 estimated number of milliseconds until preparation is complete. 4438 4439If called with shift == 0, discards any currently pending HPT and 4440returns 0 (i.e. cancels any in-progress preparation). 4441 4442flags is reserved for future expansion, currently setting any bits in 4443flags will result in an -EINVAL. 4444 4445Normally this will be called repeatedly with the same parameters until 4446it returns <= 0. The first call will initiate preparation, subsequent 4447ones will monitor preparation until it completes or fails. 4448 44494.103 KVM_PPC_RESIZE_HPT_COMMIT 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 -EFAULT if struct kvm_reinject_control cannot be read, 4458 -EINVAL if the supplied shift or flags are invalid, 4459 -ENXIO is there is no pending HPT, or the pending HPT doesn't 4460 have the requested size, 4461 -EBUSY if the pending HPT is not fully prepared, 4462 -ENOSPC if there was a hash collision when moving existing 4463 HPT entries to the new HPT, 4464 -EIO on other error conditions 4465 4466Used to implement the PAPR extension for runtime resizing of a guest's 4467Hashed Page Table (HPT). Specifically this requests that the guest be 4468transferred to working with the new HPT, essentially implementing the 4469H_RESIZE_HPT_COMMIT hypercall. 4470 4471:: 4472 4473 struct kvm_ppc_resize_hpt { 4474 __u64 flags; 4475 __u32 shift; 4476 __u32 pad; 4477 }; 4478 4479This should only be called after KVM_PPC_RESIZE_HPT_PREPARE has 4480returned 0 with the same parameters. In other cases 4481KVM_PPC_RESIZE_HPT_COMMIT will return an error (usually -ENXIO or 4482-EBUSY, though others may be possible if the preparation was started, 4483but failed). 4484 4485This will have undefined effects on the guest if it has not already 4486placed itself in a quiescent state where no vcpu will make MMU enabled 4487memory accesses. 4488 4489On successful completion, the pending HPT will become the guest's active 4490HPT and the previous HPT will be discarded. 4491 4492On failure, the guest will still be operating on its previous HPT. 4493 44944.104 KVM_X86_GET_MCE_CAP_SUPPORTED 4495----------------------------------- 4496 4497:Capability: KVM_CAP_MCE 4498:Architectures: x86 4499:Type: system ioctl 4500:Parameters: u64 mce_cap (out) 4501:Returns: 0 on success, -1 on error 4502 4503Returns supported MCE capabilities. The u64 mce_cap parameter 4504has the same format as the MSR_IA32_MCG_CAP register. Supported 4505capabilities will have the corresponding bits set. 4506 45074.105 KVM_X86_SETUP_MCE 4508----------------------- 4509 4510:Capability: KVM_CAP_MCE 4511:Architectures: x86 4512:Type: vcpu ioctl 4513:Parameters: u64 mcg_cap (in) 4514:Returns: 0 on success, 4515 -EFAULT if u64 mcg_cap cannot be read, 4516 -EINVAL if the requested number of banks is invalid, 4517 -EINVAL if requested MCE capability is not supported. 4518 4519Initializes MCE support for use. The u64 mcg_cap parameter 4520has the same format as the MSR_IA32_MCG_CAP register and 4521specifies which capabilities should be enabled. The maximum 4522supported number of error-reporting banks can be retrieved when 4523checking for KVM_CAP_MCE. The supported capabilities can be 4524retrieved with KVM_X86_GET_MCE_CAP_SUPPORTED. 4525 45264.106 KVM_X86_SET_MCE 4527--------------------- 4528 4529:Capability: KVM_CAP_MCE 4530:Architectures: x86 4531:Type: vcpu ioctl 4532:Parameters: struct kvm_x86_mce (in) 4533:Returns: 0 on success, 4534 -EFAULT if struct kvm_x86_mce cannot be read, 4535 -EINVAL if the bank number is invalid, 4536 -EINVAL if VAL bit is not set in status field. 4537 4538Inject a machine check error (MCE) into the guest. The input 4539parameter is:: 4540 4541 struct kvm_x86_mce { 4542 __u64 status; 4543 __u64 addr; 4544 __u64 misc; 4545 __u64 mcg_status; 4546 __u8 bank; 4547 __u8 pad1[7]; 4548 __u64 pad2[3]; 4549 }; 4550 4551If the MCE being reported is an uncorrected error, KVM will 4552inject it as an MCE exception into the guest. If the guest 4553MCG_STATUS register reports that an MCE is in progress, KVM 4554causes an KVM_EXIT_SHUTDOWN vmexit. 4555 4556Otherwise, if the MCE is a corrected error, KVM will just 4557store it in the corresponding bank (provided this bank is 4558not holding a previously reported uncorrected error). 4559 45604.107 KVM_S390_GET_CMMA_BITS 4561---------------------------- 4562 4563:Capability: KVM_CAP_S390_CMMA_MIGRATION 4564:Architectures: s390 4565:Type: vm ioctl 4566:Parameters: struct kvm_s390_cmma_log (in, out) 4567:Returns: 0 on success, a negative value on error 4568 4569Errors: 4570 4571 ====== ============================================================= 4572 ENOMEM not enough memory can be allocated to complete the task 4573 ENXIO if CMMA is not enabled 4574 EINVAL if KVM_S390_CMMA_PEEK is not set but migration mode was not enabled 4575 EINVAL if KVM_S390_CMMA_PEEK is not set but dirty tracking has been 4576 disabled (and thus migration mode was automatically disabled) 4577 EFAULT if the userspace address is invalid or if no page table is 4578 present for the addresses (e.g. when using hugepages). 4579 ====== ============================================================= 4580 4581This ioctl is used to get the values of the CMMA bits on the s390 4582architecture. It is meant to be used in two scenarios: 4583 4584- During live migration to save the CMMA values. Live migration needs 4585 to be enabled via the KVM_REQ_START_MIGRATION VM property. 4586- To non-destructively peek at the CMMA values, with the flag 4587 KVM_S390_CMMA_PEEK set. 4588 4589The ioctl takes parameters via the kvm_s390_cmma_log struct. The desired 4590values are written to a buffer whose location is indicated via the "values" 4591member in the kvm_s390_cmma_log struct. The values in the input struct are 4592also updated as needed. 4593 4594Each CMMA value takes up one byte. 4595 4596:: 4597 4598 struct kvm_s390_cmma_log { 4599 __u64 start_gfn; 4600 __u32 count; 4601 __u32 flags; 4602 union { 4603 __u64 remaining; 4604 __u64 mask; 4605 }; 4606 __u64 values; 4607 }; 4608 4609start_gfn is the number of the first guest frame whose CMMA values are 4610to be retrieved, 4611 4612count is the length of the buffer in bytes, 4613 4614values points to the buffer where the result will be written to. 4615 4616If count is greater than KVM_S390_SKEYS_MAX, then it is considered to be 4617KVM_S390_SKEYS_MAX. KVM_S390_SKEYS_MAX is re-used for consistency with 4618other ioctls. 4619 4620The result is written in the buffer pointed to by the field values, and 4621the values of the input parameter are updated as follows. 4622 4623Depending on the flags, different actions are performed. The only 4624supported flag so far is KVM_S390_CMMA_PEEK. 4625 4626The default behaviour if KVM_S390_CMMA_PEEK is not set is: 4627start_gfn will indicate the first page frame whose CMMA bits were dirty. 4628It is not necessarily the same as the one passed as input, as clean pages 4629are skipped. 4630 4631count will indicate the number of bytes actually written in the buffer. 4632It can (and very often will) be smaller than the input value, since the 4633buffer is only filled until 16 bytes of clean values are found (which 4634are then not copied in the buffer). Since a CMMA migration block needs 4635the base address and the length, for a total of 16 bytes, we will send 4636back some clean data if there is some dirty data afterwards, as long as 4637the size of the clean data does not exceed the size of the header. This 4638allows to minimize the amount of data to be saved or transferred over 4639the network at the expense of more roundtrips to userspace. The next 4640invocation of the ioctl will skip over all the clean values, saving 4641potentially more than just the 16 bytes we found. 4642 4643If KVM_S390_CMMA_PEEK is set: 4644the existing storage attributes are read even when not in migration 4645mode, and no other action is performed; 4646 4647the output start_gfn will be equal to the input start_gfn, 4648 4649the output count will be equal to the input count, except if the end of 4650memory has been reached. 4651 4652In both cases: 4653the field "remaining" will indicate the total number of dirty CMMA values 4654still remaining, or 0 if KVM_S390_CMMA_PEEK is set and migration mode is 4655not enabled. 4656 4657mask is unused. 4658 4659values points to the userspace buffer where the result will be stored. 4660 46614.108 KVM_S390_SET_CMMA_BITS 4662---------------------------- 4663 4664:Capability: KVM_CAP_S390_CMMA_MIGRATION 4665:Architectures: s390 4666:Type: vm ioctl 4667:Parameters: struct kvm_s390_cmma_log (in) 4668:Returns: 0 on success, a negative value on error 4669 4670This ioctl is used to set the values of the CMMA bits on the s390 4671architecture. It is meant to be used during live migration to restore 4672the CMMA values, but there are no restrictions on its use. 4673The ioctl takes parameters via the kvm_s390_cmma_values struct. 4674Each CMMA value takes up one byte. 4675 4676:: 4677 4678 struct kvm_s390_cmma_log { 4679 __u64 start_gfn; 4680 __u32 count; 4681 __u32 flags; 4682 union { 4683 __u64 remaining; 4684 __u64 mask; 4685 }; 4686 __u64 values; 4687 }; 4688 4689start_gfn indicates the starting guest frame number, 4690 4691count indicates how many values are to be considered in the buffer, 4692 4693flags is not used and must be 0. 4694 4695mask indicates which PGSTE bits are to be considered. 4696 4697remaining is not used. 4698 4699values points to the buffer in userspace where to store the values. 4700 4701This ioctl can fail with -ENOMEM if not enough memory can be allocated to 4702complete the task, with -ENXIO if CMMA is not enabled, with -EINVAL if 4703the count field is too large (e.g. more than KVM_S390_CMMA_SIZE_MAX) or 4704if the flags field was not 0, with -EFAULT if the userspace address is 4705invalid, if invalid pages are written to (e.g. after the end of memory) 4706or if no page table is present for the addresses (e.g. when using 4707hugepages). 4708 47094.109 KVM_PPC_GET_CPU_CHAR 4710-------------------------- 4711 4712:Capability: KVM_CAP_PPC_GET_CPU_CHAR 4713:Architectures: powerpc 4714:Type: vm ioctl 4715:Parameters: struct kvm_ppc_cpu_char (out) 4716:Returns: 0 on successful completion, 4717 -EFAULT if struct kvm_ppc_cpu_char cannot be written 4718 4719This ioctl gives userspace information about certain characteristics 4720of the CPU relating to speculative execution of instructions and 4721possible information leakage resulting from speculative execution (see 4722CVE-2017-5715, CVE-2017-5753 and CVE-2017-5754). The information is 4723returned in struct kvm_ppc_cpu_char, which looks like this:: 4724 4725 struct kvm_ppc_cpu_char { 4726 __u64 character; /* characteristics of the CPU */ 4727 __u64 behaviour; /* recommended software behaviour */ 4728 __u64 character_mask; /* valid bits in character */ 4729 __u64 behaviour_mask; /* valid bits in behaviour */ 4730 }; 4731 4732For extensibility, the character_mask and behaviour_mask fields 4733indicate which bits of character and behaviour have been filled in by 4734the kernel. If the set of defined bits is extended in future then 4735userspace will be able to tell whether it is running on a kernel that 4736knows about the new bits. 4737 4738The character field describes attributes of the CPU which can help 4739with preventing inadvertent information disclosure - specifically, 4740whether there is an instruction to flash-invalidate the L1 data cache 4741(ori 30,30,0 or mtspr SPRN_TRIG2,rN), whether the L1 data cache is set 4742to a mode where entries can only be used by the thread that created 4743them, whether the bcctr[l] instruction prevents speculation, and 4744whether a speculation barrier instruction (ori 31,31,0) is provided. 4745 4746The behaviour field describes actions that software should take to 4747prevent inadvertent information disclosure, and thus describes which 4748vulnerabilities the hardware is subject to; specifically whether the 4749L1 data cache should be flushed when returning to user mode from the 4750kernel, and whether a speculation barrier should be placed between an 4751array bounds check and the array access. 4752 4753These fields use the same bit definitions as the new 4754H_GET_CPU_CHARACTERISTICS hypercall. 4755 47564.110 KVM_MEMORY_ENCRYPT_OP 4757--------------------------- 4758 4759:Capability: basic 4760:Architectures: x86 4761:Type: vm 4762:Parameters: an opaque platform specific structure (in/out) 4763:Returns: 0 on success; -1 on error 4764 4765If the platform supports creating encrypted VMs then this ioctl can be used 4766for issuing platform-specific memory encryption commands to manage those 4767encrypted VMs. 4768 4769Currently, this ioctl is used for issuing Secure Encrypted Virtualization 4770(SEV) commands on AMD Processors. The SEV commands are defined in 4771Documentation/virt/kvm/x86/amd-memory-encryption.rst. 4772 47734.111 KVM_MEMORY_ENCRYPT_REG_REGION 4774----------------------------------- 4775 4776:Capability: basic 4777:Architectures: x86 4778:Type: system 4779:Parameters: struct kvm_enc_region (in) 4780:Returns: 0 on success; -1 on error 4781 4782This ioctl can be used to register a guest memory region which may 4783contain encrypted data (e.g. guest RAM, SMRAM etc). 4784 4785It is used in the SEV-enabled guest. When encryption is enabled, a guest 4786memory region may contain encrypted data. The SEV memory encryption 4787engine uses a tweak such that two identical plaintext pages, each at 4788different locations will have differing ciphertexts. So swapping or 4789moving ciphertext of those pages will not result in plaintext being 4790swapped. So relocating (or migrating) physical backing pages for the SEV 4791guest will require some additional steps. 4792 4793Note: The current SEV key management spec does not provide commands to 4794swap or migrate (move) ciphertext pages. Hence, for now we pin the guest 4795memory region registered with the ioctl. 4796 47974.112 KVM_MEMORY_ENCRYPT_UNREG_REGION 4798------------------------------------- 4799 4800:Capability: basic 4801:Architectures: x86 4802:Type: system 4803:Parameters: struct kvm_enc_region (in) 4804:Returns: 0 on success; -1 on error 4805 4806This ioctl can be used to unregister the guest memory region registered 4807with KVM_MEMORY_ENCRYPT_REG_REGION ioctl above. 4808 48094.113 KVM_HYPERV_EVENTFD 4810------------------------ 4811 4812:Capability: KVM_CAP_HYPERV_EVENTFD 4813:Architectures: x86 4814:Type: vm ioctl 4815:Parameters: struct kvm_hyperv_eventfd (in) 4816 4817This ioctl (un)registers an eventfd to receive notifications from the guest on 4818the specified Hyper-V connection id through the SIGNAL_EVENT hypercall, without 4819causing a user exit. SIGNAL_EVENT hypercall with non-zero event flag number 4820(bits 24-31) still triggers a KVM_EXIT_HYPERV_HCALL user exit. 4821 4822:: 4823 4824 struct kvm_hyperv_eventfd { 4825 __u32 conn_id; 4826 __s32 fd; 4827 __u32 flags; 4828 __u32 padding[3]; 4829 }; 4830 4831The conn_id field should fit within 24 bits:: 4832 4833 #define KVM_HYPERV_CONN_ID_MASK 0x00ffffff 4834 4835The acceptable values for the flags field are:: 4836 4837 #define KVM_HYPERV_EVENTFD_DEASSIGN (1 << 0) 4838 4839:Returns: 0 on success, 4840 -EINVAL if conn_id or flags is outside the allowed range, 4841 -ENOENT on deassign if the conn_id isn't registered, 4842 -EEXIST on assign if the conn_id is already registered 4843 48444.114 KVM_GET_NESTED_STATE 4845-------------------------- 4846 4847:Capability: KVM_CAP_NESTED_STATE 4848:Architectures: x86 4849:Type: vcpu ioctl 4850:Parameters: struct kvm_nested_state (in/out) 4851:Returns: 0 on success, -1 on error 4852 4853Errors: 4854 4855 ===== ============================================================= 4856 E2BIG the total state size exceeds the value of 'size' specified by 4857 the user; the size required will be written into size. 4858 ===== ============================================================= 4859 4860:: 4861 4862 struct kvm_nested_state { 4863 __u16 flags; 4864 __u16 format; 4865 __u32 size; 4866 4867 union { 4868 struct kvm_vmx_nested_state_hdr vmx; 4869 struct kvm_svm_nested_state_hdr svm; 4870 4871 /* Pad the header to 128 bytes. */ 4872 __u8 pad[120]; 4873 } hdr; 4874 4875 union { 4876 struct kvm_vmx_nested_state_data vmx[0]; 4877 struct kvm_svm_nested_state_data svm[0]; 4878 } data; 4879 }; 4880 4881 #define KVM_STATE_NESTED_GUEST_MODE 0x00000001 4882 #define KVM_STATE_NESTED_RUN_PENDING 0x00000002 4883 #define KVM_STATE_NESTED_EVMCS 0x00000004 4884 4885 #define KVM_STATE_NESTED_FORMAT_VMX 0 4886 #define KVM_STATE_NESTED_FORMAT_SVM 1 4887 4888 #define KVM_STATE_NESTED_VMX_VMCS_SIZE 0x1000 4889 4890 #define KVM_STATE_NESTED_VMX_SMM_GUEST_MODE 0x00000001 4891 #define KVM_STATE_NESTED_VMX_SMM_VMXON 0x00000002 4892 4893 #define KVM_STATE_VMX_PREEMPTION_TIMER_DEADLINE 0x00000001 4894 4895 struct kvm_vmx_nested_state_hdr { 4896 __u64 vmxon_pa; 4897 __u64 vmcs12_pa; 4898 4899 struct { 4900 __u16 flags; 4901 } smm; 4902 4903 __u32 flags; 4904 __u64 preemption_timer_deadline; 4905 }; 4906 4907 struct kvm_vmx_nested_state_data { 4908 __u8 vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE]; 4909 __u8 shadow_vmcs12[KVM_STATE_NESTED_VMX_VMCS_SIZE]; 4910 }; 4911 4912This ioctl copies the vcpu's nested virtualization state from the kernel to 4913userspace. 4914 4915The maximum size of the state can be retrieved by passing KVM_CAP_NESTED_STATE 4916to the KVM_CHECK_EXTENSION ioctl(). 4917 49184.115 KVM_SET_NESTED_STATE 4919-------------------------- 4920 4921:Capability: KVM_CAP_NESTED_STATE 4922:Architectures: x86 4923:Type: vcpu ioctl 4924:Parameters: struct kvm_nested_state (in) 4925:Returns: 0 on success, -1 on error 4926 4927This copies the vcpu's kvm_nested_state struct from userspace to the kernel. 4928For the definition of struct kvm_nested_state, see KVM_GET_NESTED_STATE. 4929 49304.116 KVM_(UN)REGISTER_COALESCED_MMIO 4931------------------------------------- 4932 4933:Capability: KVM_CAP_COALESCED_MMIO (for coalesced mmio) 4934 KVM_CAP_COALESCED_PIO (for coalesced pio) 4935:Architectures: all 4936:Type: vm ioctl 4937:Parameters: struct kvm_coalesced_mmio_zone 4938:Returns: 0 on success, < 0 on error 4939 4940Coalesced I/O is a performance optimization that defers hardware 4941register write emulation so that userspace exits are avoided. It is 4942typically used to reduce the overhead of emulating frequently accessed 4943hardware registers. 4944 4945When a hardware register is configured for coalesced I/O, write accesses 4946do not exit to userspace and their value is recorded in a ring buffer 4947that is shared between kernel and userspace. 4948 4949Coalesced I/O is used if one or more write accesses to a hardware 4950register can be deferred until a read or a write to another hardware 4951register on the same device. This last access will cause a vmexit and 4952userspace will process accesses from the ring buffer before emulating 4953it. That will avoid exiting to userspace on repeated writes. 4954 4955Coalesced pio is based on coalesced mmio. There is little difference 4956between coalesced mmio and pio except that coalesced pio records accesses 4957to I/O ports. 4958 49594.117 KVM_CLEAR_DIRTY_LOG 4960------------------------- 4961 4962:Capability: KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 4963:Architectures: x86, arm64, mips 4964:Type: vm ioctl 4965:Parameters: struct kvm_clear_dirty_log (in) 4966:Returns: 0 on success, -1 on error 4967 4968:: 4969 4970 /* for KVM_CLEAR_DIRTY_LOG */ 4971 struct kvm_clear_dirty_log { 4972 __u32 slot; 4973 __u32 num_pages; 4974 __u64 first_page; 4975 union { 4976 void __user *dirty_bitmap; /* one bit per page */ 4977 __u64 padding; 4978 }; 4979 }; 4980 4981The ioctl clears the dirty status of pages in a memory slot, according to 4982the bitmap that is passed in struct kvm_clear_dirty_log's dirty_bitmap 4983field. Bit 0 of the bitmap corresponds to page "first_page" in the 4984memory slot, and num_pages is the size in bits of the input bitmap. 4985first_page must be a multiple of 64; num_pages must also be a multiple of 498664 unless first_page + num_pages is the size of the memory slot. For each 4987bit that is set in the input bitmap, the corresponding page is marked "clean" 4988in KVM's dirty bitmap, and dirty tracking is re-enabled for that page 4989(for example via write-protection, or by clearing the dirty bit in 4990a page table entry). 4991 4992If KVM_CAP_MULTI_ADDRESS_SPACE is available, bits 16-31 of slot field specifies 4993the address space for which you want to clear the dirty status. See 4994KVM_SET_USER_MEMORY_REGION for details on the usage of slot field. 4995 4996This ioctl is mostly useful when KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 4997is enabled; for more information, see the description of the capability. 4998However, it can always be used as long as KVM_CHECK_EXTENSION confirms 4999that KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 is present. 5000 50014.118 KVM_GET_SUPPORTED_HV_CPUID 5002-------------------------------- 5003 5004:Capability: KVM_CAP_HYPERV_CPUID (vcpu), KVM_CAP_SYS_HYPERV_CPUID (system) 5005:Architectures: x86 5006:Type: system ioctl, vcpu ioctl 5007:Parameters: struct kvm_cpuid2 (in/out) 5008:Returns: 0 on success, -1 on error 5009 5010:: 5011 5012 struct kvm_cpuid2 { 5013 __u32 nent; 5014 __u32 padding; 5015 struct kvm_cpuid_entry2 entries[0]; 5016 }; 5017 5018 struct kvm_cpuid_entry2 { 5019 __u32 function; 5020 __u32 index; 5021 __u32 flags; 5022 __u32 eax; 5023 __u32 ebx; 5024 __u32 ecx; 5025 __u32 edx; 5026 __u32 padding[3]; 5027 }; 5028 5029This ioctl returns x86 cpuid features leaves related to Hyper-V emulation in 5030KVM. Userspace can use the information returned by this ioctl to construct 5031cpuid information presented to guests consuming Hyper-V enlightenments (e.g. 5032Windows or Hyper-V guests). 5033 5034CPUID feature leaves returned by this ioctl are defined by Hyper-V Top Level 5035Functional Specification (TLFS). These leaves can't be obtained with 5036KVM_GET_SUPPORTED_CPUID ioctl because some of them intersect with KVM feature 5037leaves (0x40000000, 0x40000001). 5038 5039Currently, the following list of CPUID leaves are returned: 5040 5041 - HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS 5042 - HYPERV_CPUID_INTERFACE 5043 - HYPERV_CPUID_VERSION 5044 - HYPERV_CPUID_FEATURES 5045 - HYPERV_CPUID_ENLIGHTMENT_INFO 5046 - HYPERV_CPUID_IMPLEMENT_LIMITS 5047 - HYPERV_CPUID_NESTED_FEATURES 5048 - HYPERV_CPUID_SYNDBG_VENDOR_AND_MAX_FUNCTIONS 5049 - HYPERV_CPUID_SYNDBG_INTERFACE 5050 - HYPERV_CPUID_SYNDBG_PLATFORM_CAPABILITIES 5051 5052Userspace invokes KVM_GET_SUPPORTED_HV_CPUID by passing a kvm_cpuid2 structure 5053with the 'nent' field indicating the number of entries in the variable-size 5054array 'entries'. If the number of entries is too low to describe all Hyper-V 5055feature leaves, an error (E2BIG) is returned. If the number is more or equal 5056to the number of Hyper-V feature leaves, the 'nent' field is adjusted to the 5057number of valid entries in the 'entries' array, which is then filled. 5058 5059'index' and 'flags' fields in 'struct kvm_cpuid_entry2' are currently reserved, 5060userspace should not expect to get any particular value there. 5061 5062Note, vcpu version of KVM_GET_SUPPORTED_HV_CPUID is currently deprecated. Unlike 5063system ioctl which exposes all supported feature bits unconditionally, vcpu 5064version has the following quirks: 5065 5066- HYPERV_CPUID_NESTED_FEATURES leaf and HV_X64_ENLIGHTENED_VMCS_RECOMMENDED 5067 feature bit are only exposed when Enlightened VMCS was previously enabled 5068 on the corresponding vCPU (KVM_CAP_HYPERV_ENLIGHTENED_VMCS). 5069- HV_STIMER_DIRECT_MODE_AVAILABLE bit is only exposed with in-kernel LAPIC. 5070 (presumes KVM_CREATE_IRQCHIP has already been called). 5071 50724.119 KVM_ARM_VCPU_FINALIZE 5073--------------------------- 5074 5075:Architectures: arm64 5076:Type: vcpu ioctl 5077:Parameters: int feature (in) 5078:Returns: 0 on success, -1 on error 5079 5080Errors: 5081 5082 ====== ============================================================== 5083 EPERM feature not enabled, needs configuration, or already finalized 5084 EINVAL feature unknown or not present 5085 ====== ============================================================== 5086 5087Recognised values for feature: 5088 5089 ===== =========================================== 5090 arm64 KVM_ARM_VCPU_SVE (requires KVM_CAP_ARM_SVE) 5091 ===== =========================================== 5092 5093Finalizes the configuration of the specified vcpu feature. 5094 5095The vcpu must already have been initialised, enabling the affected feature, by 5096means of a successful :ref:`KVM_ARM_VCPU_INIT <KVM_ARM_VCPU_INIT>` call with the 5097appropriate flag set in features[]. 5098 5099For affected vcpu features, this is a mandatory step that must be performed 5100before the vcpu is fully usable. 5101 5102Between KVM_ARM_VCPU_INIT and KVM_ARM_VCPU_FINALIZE, the feature may be 5103configured by use of ioctls such as KVM_SET_ONE_REG. The exact configuration 5104that should be performed and how to do it are feature-dependent. 5105 5106Other calls that depend on a particular feature being finalized, such as 5107KVM_RUN, KVM_GET_REG_LIST, KVM_GET_ONE_REG and KVM_SET_ONE_REG, will fail with 5108-EPERM unless the feature has already been finalized by means of a 5109KVM_ARM_VCPU_FINALIZE call. 5110 5111See KVM_ARM_VCPU_INIT for details of vcpu features that require finalization 5112using this ioctl. 5113 51144.120 KVM_SET_PMU_EVENT_FILTER 5115------------------------------ 5116 5117:Capability: KVM_CAP_PMU_EVENT_FILTER 5118:Architectures: x86 5119:Type: vm ioctl 5120:Parameters: struct kvm_pmu_event_filter (in) 5121:Returns: 0 on success, -1 on error 5122 5123Errors: 5124 5125 ====== ============================================================ 5126 EFAULT args[0] cannot be accessed 5127 EINVAL args[0] contains invalid data in the filter or filter events 5128 E2BIG nevents is too large 5129 EBUSY not enough memory to allocate the filter 5130 ====== ============================================================ 5131 5132:: 5133 5134 struct kvm_pmu_event_filter { 5135 __u32 action; 5136 __u32 nevents; 5137 __u32 fixed_counter_bitmap; 5138 __u32 flags; 5139 __u32 pad[4]; 5140 __u64 events[0]; 5141 }; 5142 5143This ioctl restricts the set of PMU events the guest can program by limiting 5144which event select and unit mask combinations are permitted. 5145 5146The argument holds a list of filter events which will be allowed or denied. 5147 5148Filter events only control general purpose counters; fixed purpose counters 5149are controlled by the fixed_counter_bitmap. 5150 5151Valid values for 'flags':: 5152 5153``0`` 5154 5155To use this mode, clear the 'flags' field. 5156 5157In this mode each event will contain an event select + unit mask. 5158 5159When the guest attempts to program the PMU the guest's event select + 5160unit mask is compared against the filter events to determine whether the 5161guest should have access. 5162 5163``KVM_PMU_EVENT_FLAG_MASKED_EVENTS`` 5164:Capability: KVM_CAP_PMU_EVENT_MASKED_EVENTS 5165 5166In this mode each filter event will contain an event select, mask, match, and 5167exclude value. To encode a masked event use:: 5168 5169 KVM_PMU_ENCODE_MASKED_ENTRY() 5170 5171An encoded event will follow this layout:: 5172 5173 Bits Description 5174 ---- ----------- 5175 7:0 event select (low bits) 5176 15:8 umask match 5177 31:16 unused 5178 35:32 event select (high bits) 5179 36:54 unused 5180 55 exclude bit 5181 63:56 umask mask 5182 5183When the guest attempts to program the PMU, these steps are followed in 5184determining if the guest should have access: 5185 5186 1. Match the event select from the guest against the filter events. 5187 2. If a match is found, match the guest's unit mask to the mask and match 5188 values of the included filter events. 5189 I.e. (unit mask & mask) == match && !exclude. 5190 3. If a match is found, match the guest's unit mask to the mask and match 5191 values of the excluded filter events. 5192 I.e. (unit mask & mask) == match && exclude. 5193 4. 5194 a. If an included match is found and an excluded match is not found, filter 5195 the event. 5196 b. For everything else, do not filter the event. 5197 5. 5198 a. If the event is filtered and it's an allow list, allow the guest to 5199 program the event. 5200 b. If the event is filtered and it's a deny list, do not allow the guest to 5201 program the event. 5202 5203When setting a new pmu event filter, -EINVAL will be returned if any of the 5204unused fields are set or if any of the high bits (35:32) in the event 5205select are set when called on Intel. 5206 5207Valid values for 'action':: 5208 5209 #define KVM_PMU_EVENT_ALLOW 0 5210 #define KVM_PMU_EVENT_DENY 1 5211 5212Via this API, KVM userspace can also control the behavior of the VM's fixed 5213counters (if any) by configuring the "action" and "fixed_counter_bitmap" fields. 5214 5215Specifically, KVM follows the following pseudo-code when determining whether to 5216allow the guest FixCtr[i] to count its pre-defined fixed event:: 5217 5218 FixCtr[i]_is_allowed = (action == ALLOW) && (bitmap & BIT(i)) || 5219 (action == DENY) && !(bitmap & BIT(i)); 5220 FixCtr[i]_is_denied = !FixCtr[i]_is_allowed; 5221 5222KVM always consumes fixed_counter_bitmap, it's userspace's responsibility to 5223ensure fixed_counter_bitmap is set correctly, e.g. if userspace wants to define 5224a filter that only affects general purpose counters. 5225 5226Note, the "events" field also applies to fixed counters' hardcoded event_select 5227and unit_mask values. "fixed_counter_bitmap" has higher priority than "events" 5228if there is a contradiction between the two. 5229 52304.121 KVM_PPC_SVM_OFF 5231--------------------- 5232 5233:Capability: basic 5234:Architectures: powerpc 5235:Type: vm ioctl 5236:Parameters: none 5237:Returns: 0 on successful completion, 5238 5239Errors: 5240 5241 ====== ================================================================ 5242 EINVAL if ultravisor failed to terminate the secure guest 5243 ENOMEM if hypervisor failed to allocate new radix page tables for guest 5244 ====== ================================================================ 5245 5246This ioctl is used to turn off the secure mode of the guest or transition 5247the guest from secure mode to normal mode. This is invoked when the guest 5248is reset. This has no effect if called for a normal guest. 5249 5250This ioctl issues an ultravisor call to terminate the secure guest, 5251unpins the VPA pages and releases all the device pages that are used to 5252track the secure pages by hypervisor. 5253 52544.122 KVM_S390_NORMAL_RESET 5255--------------------------- 5256 5257:Capability: KVM_CAP_S390_VCPU_RESETS 5258:Architectures: s390 5259:Type: vcpu ioctl 5260:Parameters: none 5261:Returns: 0 5262 5263This ioctl resets VCPU registers and control structures according to 5264the cpu reset definition in the POP (Principles Of Operation). 5265 52664.123 KVM_S390_INITIAL_RESET 5267---------------------------- 5268 5269:Capability: basic 5270:Architectures: s390 5271:Type: vcpu ioctl 5272:Parameters: none 5273:Returns: 0 5274 5275This ioctl resets VCPU registers and control structures according to 5276the initial cpu reset definition in the POP. However, the cpu is not 5277put into ESA mode. This reset is a superset of the normal reset. 5278 52794.124 KVM_S390_CLEAR_RESET 5280-------------------------- 5281 5282:Capability: KVM_CAP_S390_VCPU_RESETS 5283:Architectures: s390 5284:Type: vcpu ioctl 5285:Parameters: none 5286:Returns: 0 5287 5288This ioctl resets VCPU registers and control structures according to 5289the clear cpu reset definition in the POP. However, the cpu is not put 5290into ESA mode. This reset is a superset of the initial reset. 5291 5292 52934.125 KVM_S390_PV_COMMAND 5294------------------------- 5295 5296:Capability: KVM_CAP_S390_PROTECTED 5297:Architectures: s390 5298:Type: vm ioctl 5299:Parameters: struct kvm_pv_cmd 5300:Returns: 0 on success, < 0 on error 5301 5302:: 5303 5304 struct kvm_pv_cmd { 5305 __u32 cmd; /* Command to be executed */ 5306 __u16 rc; /* Ultravisor return code */ 5307 __u16 rrc; /* Ultravisor return reason code */ 5308 __u64 data; /* Data or address */ 5309 __u32 flags; /* flags for future extensions. Must be 0 for now */ 5310 __u32 reserved[3]; 5311 }; 5312 5313**Ultravisor return codes** 5314The Ultravisor return (reason) codes are provided by the kernel if a 5315Ultravisor call has been executed to achieve the results expected by 5316the command. Therefore they are independent of the IOCTL return 5317code. If KVM changes `rc`, its value will always be greater than 0 5318hence setting it to 0 before issuing a PV command is advised to be 5319able to detect a change of `rc`. 5320 5321**cmd values:** 5322 5323KVM_PV_ENABLE 5324 Allocate memory and register the VM with the Ultravisor, thereby 5325 donating memory to the Ultravisor that will become inaccessible to 5326 KVM. All existing CPUs are converted to protected ones. After this 5327 command has succeeded, any CPU added via hotplug will become 5328 protected during its creation as well. 5329 5330 Errors: 5331 5332 ===== ============================= 5333 EINTR an unmasked signal is pending 5334 ===== ============================= 5335 5336KVM_PV_DISABLE 5337 Deregister the VM from the Ultravisor and reclaim the memory that had 5338 been donated to the Ultravisor, making it usable by the kernel again. 5339 All registered VCPUs are converted back to non-protected ones. If a 5340 previous protected VM had been prepared for asynchronous teardown with 5341 KVM_PV_ASYNC_CLEANUP_PREPARE and not subsequently torn down with 5342 KVM_PV_ASYNC_CLEANUP_PERFORM, it will be torn down in this call 5343 together with the current protected VM. 5344 5345KVM_PV_VM_SET_SEC_PARMS 5346 Pass the image header from VM memory to the Ultravisor in 5347 preparation of image unpacking and verification. 5348 5349KVM_PV_VM_UNPACK 5350 Unpack (protect and decrypt) a page of the encrypted boot image. 5351 5352KVM_PV_VM_VERIFY 5353 Verify the integrity of the unpacked image. Only if this succeeds, 5354 KVM is allowed to start protected VCPUs. 5355 5356KVM_PV_INFO 5357 :Capability: KVM_CAP_S390_PROTECTED_DUMP 5358 5359 Presents an API that provides Ultravisor related data to userspace 5360 via subcommands. len_max is the size of the user space buffer, 5361 len_written is KVM's indication of how much bytes of that buffer 5362 were actually written to. len_written can be used to determine the 5363 valid fields if more response fields are added in the future. 5364 5365 :: 5366 5367 enum pv_cmd_info_id { 5368 KVM_PV_INFO_VM, 5369 KVM_PV_INFO_DUMP, 5370 }; 5371 5372 struct kvm_s390_pv_info_header { 5373 __u32 id; 5374 __u32 len_max; 5375 __u32 len_written; 5376 __u32 reserved; 5377 }; 5378 5379 struct kvm_s390_pv_info { 5380 struct kvm_s390_pv_info_header header; 5381 struct kvm_s390_pv_info_dump dump; 5382 struct kvm_s390_pv_info_vm vm; 5383 }; 5384 5385**subcommands:** 5386 5387 KVM_PV_INFO_VM 5388 This subcommand provides basic Ultravisor information for PV 5389 hosts. These values are likely also exported as files in the sysfs 5390 firmware UV query interface but they are more easily available to 5391 programs in this API. 5392 5393 The installed calls and feature_indication members provide the 5394 installed UV calls and the UV's other feature indications. 5395 5396 The max_* members provide information about the maximum number of PV 5397 vcpus, PV guests and PV guest memory size. 5398 5399 :: 5400 5401 struct kvm_s390_pv_info_vm { 5402 __u64 inst_calls_list[4]; 5403 __u64 max_cpus; 5404 __u64 max_guests; 5405 __u64 max_guest_addr; 5406 __u64 feature_indication; 5407 }; 5408 5409 5410 KVM_PV_INFO_DUMP 5411 This subcommand provides information related to dumping PV guests. 5412 5413 :: 5414 5415 struct kvm_s390_pv_info_dump { 5416 __u64 dump_cpu_buffer_len; 5417 __u64 dump_config_mem_buffer_per_1m; 5418 __u64 dump_config_finalize_len; 5419 }; 5420 5421KVM_PV_DUMP 5422 :Capability: KVM_CAP_S390_PROTECTED_DUMP 5423 5424 Presents an API that provides calls which facilitate dumping a 5425 protected VM. 5426 5427 :: 5428 5429 struct kvm_s390_pv_dmp { 5430 __u64 subcmd; 5431 __u64 buff_addr; 5432 __u64 buff_len; 5433 __u64 gaddr; /* For dump storage state */ 5434 }; 5435 5436 **subcommands:** 5437 5438 KVM_PV_DUMP_INIT 5439 Initializes the dump process of a protected VM. If this call does 5440 not succeed all other subcommands will fail with -EINVAL. This 5441 subcommand will return -EINVAL if a dump process has not yet been 5442 completed. 5443 5444 Not all PV vms can be dumped, the owner needs to set `dump 5445 allowed` PCF bit 34 in the SE header to allow dumping. 5446 5447 KVM_PV_DUMP_CONFIG_STOR_STATE 5448 Stores `buff_len` bytes of tweak component values starting with 5449 the 1MB block specified by the absolute guest address 5450 (`gaddr`). `buff_len` needs to be `conf_dump_storage_state_len` 5451 aligned and at least >= the `conf_dump_storage_state_len` value 5452 provided by the dump uv_info data. buff_user might be written to 5453 even if an error rc is returned. For instance if we encounter a 5454 fault after writing the first page of data. 5455 5456 KVM_PV_DUMP_COMPLETE 5457 If the subcommand succeeds it completes the dump process and lets 5458 KVM_PV_DUMP_INIT be called again. 5459 5460 On success `conf_dump_finalize_len` bytes of completion data will be 5461 stored to the `buff_addr`. The completion data contains a key 5462 derivation seed, IV, tweak nonce and encryption keys as well as an 5463 authentication tag all of which are needed to decrypt the dump at a 5464 later time. 5465 5466KVM_PV_ASYNC_CLEANUP_PREPARE 5467 :Capability: KVM_CAP_S390_PROTECTED_ASYNC_DISABLE 5468 5469 Prepare the current protected VM for asynchronous teardown. Most 5470 resources used by the current protected VM will be set aside for a 5471 subsequent asynchronous teardown. The current protected VM will then 5472 resume execution immediately as non-protected. There can be at most 5473 one protected VM prepared for asynchronous teardown at any time. If 5474 a protected VM had already been prepared for teardown without 5475 subsequently calling KVM_PV_ASYNC_CLEANUP_PERFORM, this call will 5476 fail. In that case, the userspace process should issue a normal 5477 KVM_PV_DISABLE. The resources set aside with this call will need to 5478 be cleaned up with a subsequent call to KVM_PV_ASYNC_CLEANUP_PERFORM 5479 or KVM_PV_DISABLE, otherwise they will be cleaned up when KVM 5480 terminates. KVM_PV_ASYNC_CLEANUP_PREPARE can be called again as soon 5481 as cleanup starts, i.e. before KVM_PV_ASYNC_CLEANUP_PERFORM finishes. 5482 5483KVM_PV_ASYNC_CLEANUP_PERFORM 5484 :Capability: KVM_CAP_S390_PROTECTED_ASYNC_DISABLE 5485 5486 Tear down the protected VM previously prepared for teardown with 5487 KVM_PV_ASYNC_CLEANUP_PREPARE. The resources that had been set aside 5488 will be freed during the execution of this command. This PV command 5489 should ideally be issued by userspace from a separate thread. If a 5490 fatal signal is received (or the process terminates naturally), the 5491 command will terminate immediately without completing, and the normal 5492 KVM shutdown procedure will take care of cleaning up all remaining 5493 protected VMs, including the ones whose teardown was interrupted by 5494 process termination. 5495 54964.126 KVM_XEN_HVM_SET_ATTR 5497-------------------------- 5498 5499:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5500:Architectures: x86 5501:Type: vm ioctl 5502:Parameters: struct kvm_xen_hvm_attr 5503:Returns: 0 on success, < 0 on error 5504 5505:: 5506 5507 struct kvm_xen_hvm_attr { 5508 __u16 type; 5509 __u16 pad[3]; 5510 union { 5511 __u8 long_mode; 5512 __u8 vector; 5513 __u8 runstate_update_flag; 5514 union { 5515 __u64 gfn; 5516 __u64 hva; 5517 } shared_info; 5518 struct { 5519 __u32 send_port; 5520 __u32 type; /* EVTCHNSTAT_ipi / EVTCHNSTAT_interdomain */ 5521 __u32 flags; 5522 union { 5523 struct { 5524 __u32 port; 5525 __u32 vcpu; 5526 __u32 priority; 5527 } port; 5528 struct { 5529 __u32 port; /* Zero for eventfd */ 5530 __s32 fd; 5531 } eventfd; 5532 __u32 padding[4]; 5533 } deliver; 5534 } evtchn; 5535 __u32 xen_version; 5536 __u64 pad[8]; 5537 } u; 5538 }; 5539 5540type values: 5541 5542KVM_XEN_ATTR_TYPE_LONG_MODE 5543 Sets the ABI mode of the VM to 32-bit or 64-bit (long mode). This 5544 determines the layout of the shared_info page exposed to the VM. 5545 5546KVM_XEN_ATTR_TYPE_SHARED_INFO 5547 Sets the guest physical frame number at which the Xen shared_info 5548 page resides. Note that although Xen places vcpu_info for the first 5549 32 vCPUs in the shared_info page, KVM does not automatically do so 5550 and instead requires that KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO or 5551 KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO_HVA be used explicitly even when 5552 the vcpu_info for a given vCPU resides at the "default" location 5553 in the shared_info page. This is because KVM may not be aware of 5554 the Xen CPU id which is used as the index into the vcpu_info[] 5555 array, so may know the correct default location. 5556 5557 Note that the shared_info page may be constantly written to by KVM; 5558 it contains the event channel bitmap used to deliver interrupts to 5559 a Xen guest, amongst other things. It is exempt from dirty tracking 5560 mechanisms — KVM will not explicitly mark the page as dirty each 5561 time an event channel interrupt is delivered to the guest! Thus, 5562 userspace should always assume that the designated GFN is dirty if 5563 any vCPU has been running or any event channel interrupts can be 5564 routed to the guest. 5565 5566 Setting the gfn to KVM_XEN_INVALID_GFN will disable the shared_info 5567 page. 5568 5569KVM_XEN_ATTR_TYPE_SHARED_INFO_HVA 5570 If the KVM_XEN_HVM_CONFIG_SHARED_INFO_HVA flag is also set in the 5571 Xen capabilities, then this attribute may be used to set the 5572 userspace address at which the shared_info page resides, which 5573 will always be fixed in the VMM regardless of where it is mapped 5574 in guest physical address space. This attribute should be used in 5575 preference to KVM_XEN_ATTR_TYPE_SHARED_INFO as it avoids 5576 unnecessary invalidation of an internal cache when the page is 5577 re-mapped in guest physcial address space. 5578 5579 Setting the hva to zero will disable the shared_info page. 5580 5581KVM_XEN_ATTR_TYPE_UPCALL_VECTOR 5582 Sets the exception vector used to deliver Xen event channel upcalls. 5583 This is the HVM-wide vector injected directly by the hypervisor 5584 (not through the local APIC), typically configured by a guest via 5585 HVM_PARAM_CALLBACK_IRQ. This can be disabled again (e.g. for guest 5586 SHUTDOWN_soft_reset) by setting it to zero. 5587 5588KVM_XEN_ATTR_TYPE_EVTCHN 5589 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5590 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It configures 5591 an outbound port number for interception of EVTCHNOP_send requests 5592 from the guest. A given sending port number may be directed back to 5593 a specified vCPU (by APIC ID) / port / priority on the guest, or to 5594 trigger events on an eventfd. The vCPU and priority can be changed 5595 by setting KVM_XEN_EVTCHN_UPDATE in a subsequent call, but other 5596 fields cannot change for a given sending port. A port mapping is 5597 removed by using KVM_XEN_EVTCHN_DEASSIGN in the flags field. Passing 5598 KVM_XEN_EVTCHN_RESET in the flags field removes all interception of 5599 outbound event channels. The values of the flags field are mutually 5600 exclusive and cannot be combined as a bitmask. 5601 5602KVM_XEN_ATTR_TYPE_XEN_VERSION 5603 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5604 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It configures 5605 the 32-bit version code returned to the guest when it invokes the 5606 XENVER_version call; typically (XEN_MAJOR << 16 | XEN_MINOR). PV 5607 Xen guests will often use this to as a dummy hypercall to trigger 5608 event channel delivery, so responding within the kernel without 5609 exiting to userspace is beneficial. 5610 5611KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG 5612 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5613 support for KVM_XEN_HVM_CONFIG_RUNSTATE_UPDATE_FLAG. It enables the 5614 XEN_RUNSTATE_UPDATE flag which allows guest vCPUs to safely read 5615 other vCPUs' vcpu_runstate_info. Xen guests enable this feature via 5616 the VMASST_TYPE_runstate_update_flag of the HYPERVISOR_vm_assist 5617 hypercall. 5618 56194.127 KVM_XEN_HVM_GET_ATTR 5620-------------------------- 5621 5622:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5623:Architectures: x86 5624:Type: vm ioctl 5625:Parameters: struct kvm_xen_hvm_attr 5626:Returns: 0 on success, < 0 on error 5627 5628Allows Xen VM attributes to be read. For the structure and types, 5629see KVM_XEN_HVM_SET_ATTR above. The KVM_XEN_ATTR_TYPE_EVTCHN 5630attribute cannot be read. 5631 56324.128 KVM_XEN_VCPU_SET_ATTR 5633--------------------------- 5634 5635:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5636:Architectures: x86 5637:Type: vcpu ioctl 5638:Parameters: struct kvm_xen_vcpu_attr 5639:Returns: 0 on success, < 0 on error 5640 5641:: 5642 5643 struct kvm_xen_vcpu_attr { 5644 __u16 type; 5645 __u16 pad[3]; 5646 union { 5647 __u64 gpa; 5648 __u64 pad[4]; 5649 struct { 5650 __u64 state; 5651 __u64 state_entry_time; 5652 __u64 time_running; 5653 __u64 time_runnable; 5654 __u64 time_blocked; 5655 __u64 time_offline; 5656 } runstate; 5657 __u32 vcpu_id; 5658 struct { 5659 __u32 port; 5660 __u32 priority; 5661 __u64 expires_ns; 5662 } timer; 5663 __u8 vector; 5664 } u; 5665 }; 5666 5667type values: 5668 5669KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO 5670 Sets the guest physical address of the vcpu_info for a given vCPU. 5671 As with the shared_info page for the VM, the corresponding page may be 5672 dirtied at any time if event channel interrupt delivery is enabled, so 5673 userspace should always assume that the page is dirty without relying 5674 on dirty logging. Setting the gpa to KVM_XEN_INVALID_GPA will disable 5675 the vcpu_info. 5676 5677KVM_XEN_VCPU_ATTR_TYPE_VCPU_INFO_HVA 5678 If the KVM_XEN_HVM_CONFIG_SHARED_INFO_HVA flag is also set in the 5679 Xen capabilities, then this attribute may be used to set the 5680 userspace address of the vcpu_info for a given vCPU. It should 5681 only be used when the vcpu_info resides at the "default" location 5682 in the shared_info page. In this case it is safe to assume the 5683 userspace address will not change, because the shared_info page is 5684 an overlay on guest memory and remains at a fixed host address 5685 regardless of where it is mapped in guest physical address space 5686 and hence unnecessary invalidation of an internal cache may be 5687 avoided if the guest memory layout is modified. 5688 If the vcpu_info does not reside at the "default" location then 5689 it is not guaranteed to remain at the same host address and 5690 hence the aforementioned cache invalidation is required. 5691 5692KVM_XEN_VCPU_ATTR_TYPE_VCPU_TIME_INFO 5693 Sets the guest physical address of an additional pvclock structure 5694 for a given vCPU. This is typically used for guest vsyscall support. 5695 Setting the gpa to KVM_XEN_INVALID_GPA will disable the structure. 5696 5697KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR 5698 Sets the guest physical address of the vcpu_runstate_info for a given 5699 vCPU. This is how a Xen guest tracks CPU state such as steal time. 5700 Setting the gpa to KVM_XEN_INVALID_GPA will disable the runstate area. 5701 5702KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_CURRENT 5703 Sets the runstate (RUNSTATE_running/_runnable/_blocked/_offline) of 5704 the given vCPU from the .u.runstate.state member of the structure. 5705 KVM automatically accounts running and runnable time but blocked 5706 and offline states are only entered explicitly. 5707 5708KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_DATA 5709 Sets all fields of the vCPU runstate data from the .u.runstate member 5710 of the structure, including the current runstate. The state_entry_time 5711 must equal the sum of the other four times. 5712 5713KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST 5714 This *adds* the contents of the .u.runstate members of the structure 5715 to the corresponding members of the given vCPU's runstate data, thus 5716 permitting atomic adjustments to the runstate times. The adjustment 5717 to the state_entry_time must equal the sum of the adjustments to the 5718 other four times. The state field must be set to -1, or to a valid 5719 runstate value (RUNSTATE_running, RUNSTATE_runnable, RUNSTATE_blocked 5720 or RUNSTATE_offline) to set the current accounted state as of the 5721 adjusted state_entry_time. 5722 5723KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID 5724 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5725 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It sets the Xen 5726 vCPU ID of the given vCPU, to allow timer-related VCPU operations to 5727 be intercepted by KVM. 5728 5729KVM_XEN_VCPU_ATTR_TYPE_TIMER 5730 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5731 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It sets the 5732 event channel port/priority for the VIRQ_TIMER of the vCPU, as well 5733 as allowing a pending timer to be saved/restored. Setting the timer 5734 port to zero disables kernel handling of the singleshot timer. 5735 5736KVM_XEN_VCPU_ATTR_TYPE_UPCALL_VECTOR 5737 This attribute is available when the KVM_CAP_XEN_HVM ioctl indicates 5738 support for KVM_XEN_HVM_CONFIG_EVTCHN_SEND features. It sets the 5739 per-vCPU local APIC upcall vector, configured by a Xen guest with 5740 the HVMOP_set_evtchn_upcall_vector hypercall. This is typically 5741 used by Windows guests, and is distinct from the HVM-wide upcall 5742 vector configured with HVM_PARAM_CALLBACK_IRQ. It is disabled by 5743 setting the vector to zero. 5744 5745 57464.129 KVM_XEN_VCPU_GET_ATTR 5747--------------------------- 5748 5749:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_SHARED_INFO 5750:Architectures: x86 5751:Type: vcpu ioctl 5752:Parameters: struct kvm_xen_vcpu_attr 5753:Returns: 0 on success, < 0 on error 5754 5755Allows Xen vCPU attributes to be read. For the structure and types, 5756see KVM_XEN_VCPU_SET_ATTR above. 5757 5758The KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST type may not be used 5759with the KVM_XEN_VCPU_GET_ATTR ioctl. 5760 57614.130 KVM_ARM_MTE_COPY_TAGS 5762--------------------------- 5763 5764:Capability: KVM_CAP_ARM_MTE 5765:Architectures: arm64 5766:Type: vm ioctl 5767:Parameters: struct kvm_arm_copy_mte_tags 5768:Returns: number of bytes copied, < 0 on error (-EINVAL for incorrect 5769 arguments, -EFAULT if memory cannot be accessed). 5770 5771:: 5772 5773 struct kvm_arm_copy_mte_tags { 5774 __u64 guest_ipa; 5775 __u64 length; 5776 void __user *addr; 5777 __u64 flags; 5778 __u64 reserved[2]; 5779 }; 5780 5781Copies Memory Tagging Extension (MTE) tags to/from guest tag memory. The 5782``guest_ipa`` and ``length`` fields must be ``PAGE_SIZE`` aligned. 5783``length`` must not be bigger than 2^31 - PAGE_SIZE bytes. The ``addr`` 5784field must point to a buffer which the tags will be copied to or from. 5785 5786``flags`` specifies the direction of copy, either ``KVM_ARM_TAGS_TO_GUEST`` or 5787``KVM_ARM_TAGS_FROM_GUEST``. 5788 5789The size of the buffer to store the tags is ``(length / 16)`` bytes 5790(granules in MTE are 16 bytes long). Each byte contains a single tag 5791value. This matches the format of ``PTRACE_PEEKMTETAGS`` and 5792``PTRACE_POKEMTETAGS``. 5793 5794If an error occurs before any data is copied then a negative error code is 5795returned. If some tags have been copied before an error occurs then the number 5796of bytes successfully copied is returned. If the call completes successfully 5797then ``length`` is returned. 5798 57994.131 KVM_GET_SREGS2 5800-------------------- 5801 5802:Capability: KVM_CAP_SREGS2 5803:Architectures: x86 5804:Type: vcpu ioctl 5805:Parameters: struct kvm_sregs2 (out) 5806:Returns: 0 on success, -1 on error 5807 5808Reads special registers from the vcpu. 5809This ioctl (when supported) replaces the KVM_GET_SREGS. 5810 5811:: 5812 5813 struct kvm_sregs2 { 5814 /* out (KVM_GET_SREGS2) / in (KVM_SET_SREGS2) */ 5815 struct kvm_segment cs, ds, es, fs, gs, ss; 5816 struct kvm_segment tr, ldt; 5817 struct kvm_dtable gdt, idt; 5818 __u64 cr0, cr2, cr3, cr4, cr8; 5819 __u64 efer; 5820 __u64 apic_base; 5821 __u64 flags; 5822 __u64 pdptrs[4]; 5823 }; 5824 5825flags values for ``kvm_sregs2``: 5826 5827``KVM_SREGS2_FLAGS_PDPTRS_VALID`` 5828 5829 Indicates that the struct contains valid PDPTR values. 5830 5831 58324.132 KVM_SET_SREGS2 5833-------------------- 5834 5835:Capability: KVM_CAP_SREGS2 5836:Architectures: x86 5837:Type: vcpu ioctl 5838:Parameters: struct kvm_sregs2 (in) 5839:Returns: 0 on success, -1 on error 5840 5841Writes special registers into the vcpu. 5842See KVM_GET_SREGS2 for the data structures. 5843This ioctl (when supported) replaces the KVM_SET_SREGS. 5844 58454.133 KVM_GET_STATS_FD 5846---------------------- 5847 5848:Capability: KVM_CAP_STATS_BINARY_FD 5849:Architectures: all 5850:Type: vm ioctl, vcpu ioctl 5851:Parameters: none 5852:Returns: statistics file descriptor on success, < 0 on error 5853 5854Errors: 5855 5856 ====== ====================================================== 5857 ENOMEM if the fd could not be created due to lack of memory 5858 EMFILE if the number of opened files exceeds the limit 5859 ====== ====================================================== 5860 5861The returned file descriptor can be used to read VM/vCPU statistics data in 5862binary format. The data in the file descriptor consists of four blocks 5863organized as follows: 5864 5865+-------------+ 5866| Header | 5867+-------------+ 5868| id string | 5869+-------------+ 5870| Descriptors | 5871+-------------+ 5872| Stats Data | 5873+-------------+ 5874 5875Apart from the header starting at offset 0, please be aware that it is 5876not guaranteed that the four blocks are adjacent or in the above order; 5877the offsets of the id, descriptors and data blocks are found in the 5878header. However, all four blocks are aligned to 64 bit offsets in the 5879file and they do not overlap. 5880 5881All blocks except the data block are immutable. Userspace can read them 5882only one time after retrieving the file descriptor, and then use ``pread`` or 5883``lseek`` to read the statistics repeatedly. 5884 5885All data is in system endianness. 5886 5887The format of the header is as follows:: 5888 5889 struct kvm_stats_header { 5890 __u32 flags; 5891 __u32 name_size; 5892 __u32 num_desc; 5893 __u32 id_offset; 5894 __u32 desc_offset; 5895 __u32 data_offset; 5896 }; 5897 5898The ``flags`` field is not used at the moment. It is always read as 0. 5899 5900The ``name_size`` field is the size (in byte) of the statistics name string 5901(including trailing '\0') which is contained in the "id string" block and 5902appended at the end of every descriptor. 5903 5904The ``num_desc`` field is the number of descriptors that are included in the 5905descriptor block. (The actual number of values in the data block may be 5906larger, since each descriptor may comprise more than one value). 5907 5908The ``id_offset`` field is the offset of the id string from the start of the 5909file indicated by the file descriptor. It is a multiple of 8. 5910 5911The ``desc_offset`` field is the offset of the Descriptors block from the start 5912of the file indicated by the file descriptor. It is a multiple of 8. 5913 5914The ``data_offset`` field is the offset of the Stats Data block from the start 5915of the file indicated by the file descriptor. It is a multiple of 8. 5916 5917The id string block contains a string which identifies the file descriptor on 5918which KVM_GET_STATS_FD was invoked. The size of the block, including the 5919trailing ``'\0'``, is indicated by the ``name_size`` field in the header. 5920 5921The descriptors block is only needed to be read once for the lifetime of the 5922file descriptor contains a sequence of ``struct kvm_stats_desc``, each followed 5923by a string of size ``name_size``. 5924:: 5925 5926 #define KVM_STATS_TYPE_SHIFT 0 5927 #define KVM_STATS_TYPE_MASK (0xF << KVM_STATS_TYPE_SHIFT) 5928 #define KVM_STATS_TYPE_CUMULATIVE (0x0 << KVM_STATS_TYPE_SHIFT) 5929 #define KVM_STATS_TYPE_INSTANT (0x1 << KVM_STATS_TYPE_SHIFT) 5930 #define KVM_STATS_TYPE_PEAK (0x2 << KVM_STATS_TYPE_SHIFT) 5931 #define KVM_STATS_TYPE_LINEAR_HIST (0x3 << KVM_STATS_TYPE_SHIFT) 5932 #define KVM_STATS_TYPE_LOG_HIST (0x4 << KVM_STATS_TYPE_SHIFT) 5933 #define KVM_STATS_TYPE_MAX KVM_STATS_TYPE_LOG_HIST 5934 5935 #define KVM_STATS_UNIT_SHIFT 4 5936 #define KVM_STATS_UNIT_MASK (0xF << KVM_STATS_UNIT_SHIFT) 5937 #define KVM_STATS_UNIT_NONE (0x0 << KVM_STATS_UNIT_SHIFT) 5938 #define KVM_STATS_UNIT_BYTES (0x1 << KVM_STATS_UNIT_SHIFT) 5939 #define KVM_STATS_UNIT_SECONDS (0x2 << KVM_STATS_UNIT_SHIFT) 5940 #define KVM_STATS_UNIT_CYCLES (0x3 << KVM_STATS_UNIT_SHIFT) 5941 #define KVM_STATS_UNIT_BOOLEAN (0x4 << KVM_STATS_UNIT_SHIFT) 5942 #define KVM_STATS_UNIT_MAX KVM_STATS_UNIT_BOOLEAN 5943 5944 #define KVM_STATS_BASE_SHIFT 8 5945 #define KVM_STATS_BASE_MASK (0xF << KVM_STATS_BASE_SHIFT) 5946 #define KVM_STATS_BASE_POW10 (0x0 << KVM_STATS_BASE_SHIFT) 5947 #define KVM_STATS_BASE_POW2 (0x1 << KVM_STATS_BASE_SHIFT) 5948 #define KVM_STATS_BASE_MAX KVM_STATS_BASE_POW2 5949 5950 struct kvm_stats_desc { 5951 __u32 flags; 5952 __s16 exponent; 5953 __u16 size; 5954 __u32 offset; 5955 __u32 bucket_size; 5956 char name[]; 5957 }; 5958 5959The ``flags`` field contains the type and unit of the statistics data described 5960by this descriptor. Its endianness is CPU native. 5961The following flags are supported: 5962 5963Bits 0-3 of ``flags`` encode the type: 5964 5965 * ``KVM_STATS_TYPE_CUMULATIVE`` 5966 The statistics reports a cumulative count. The value of data can only be increased. 5967 Most of the counters used in KVM are of this type. 5968 The corresponding ``size`` field for this type is always 1. 5969 All cumulative statistics data are read/write. 5970 * ``KVM_STATS_TYPE_INSTANT`` 5971 The statistics reports an instantaneous value. Its value can be increased or 5972 decreased. This type is usually used as a measurement of some resources, 5973 like the number of dirty pages, the number of large pages, etc. 5974 All instant statistics are read only. 5975 The corresponding ``size`` field for this type is always 1. 5976 * ``KVM_STATS_TYPE_PEAK`` 5977 The statistics data reports a peak value, for example the maximum number 5978 of items in a hash table bucket, the longest time waited and so on. 5979 The value of data can only be increased. 5980 The corresponding ``size`` field for this type is always 1. 5981 * ``KVM_STATS_TYPE_LINEAR_HIST`` 5982 The statistic is reported as a linear histogram. The number of 5983 buckets is specified by the ``size`` field. The size of buckets is specified 5984 by the ``hist_param`` field. The range of the Nth bucket (1 <= N < ``size``) 5985 is [``hist_param``*(N-1), ``hist_param``*N), while the range of the last 5986 bucket is [``hist_param``*(``size``-1), +INF). (+INF means positive infinity 5987 value.) 5988 * ``KVM_STATS_TYPE_LOG_HIST`` 5989 The statistic is reported as a logarithmic histogram. The number of 5990 buckets is specified by the ``size`` field. The range of the first bucket is 5991 [0, 1), while the range of the last bucket is [pow(2, ``size``-2), +INF). 5992 Otherwise, The Nth bucket (1 < N < ``size``) covers 5993 [pow(2, N-2), pow(2, N-1)). 5994 5995Bits 4-7 of ``flags`` encode the unit: 5996 5997 * ``KVM_STATS_UNIT_NONE`` 5998 There is no unit for the value of statistics data. This usually means that 5999 the value is a simple counter of an event. 6000 * ``KVM_STATS_UNIT_BYTES`` 6001 It indicates that the statistics data is used to measure memory size, in the 6002 unit of Byte, KiByte, MiByte, GiByte, etc. The unit of the data is 6003 determined by the ``exponent`` field in the descriptor. 6004 * ``KVM_STATS_UNIT_SECONDS`` 6005 It indicates that the statistics data is used to measure time or latency. 6006 * ``KVM_STATS_UNIT_CYCLES`` 6007 It indicates that the statistics data is used to measure CPU clock cycles. 6008 * ``KVM_STATS_UNIT_BOOLEAN`` 6009 It indicates that the statistic will always be either 0 or 1. Boolean 6010 statistics of "peak" type will never go back from 1 to 0. Boolean 6011 statistics can be linear histograms (with two buckets) but not logarithmic 6012 histograms. 6013 6014Note that, in the case of histograms, the unit applies to the bucket 6015ranges, while the bucket value indicates how many samples fell in the 6016bucket's range. 6017 6018Bits 8-11 of ``flags``, together with ``exponent``, encode the scale of the 6019unit: 6020 6021 * ``KVM_STATS_BASE_POW10`` 6022 The scale is based on power of 10. It is used for measurement of time and 6023 CPU clock cycles. For example, an exponent of -9 can be used with 6024 ``KVM_STATS_UNIT_SECONDS`` to express that the unit is nanoseconds. 6025 * ``KVM_STATS_BASE_POW2`` 6026 The scale is based on power of 2. It is used for measurement of memory size. 6027 For example, an exponent of 20 can be used with ``KVM_STATS_UNIT_BYTES`` to 6028 express that the unit is MiB. 6029 6030The ``size`` field is the number of values of this statistics data. Its 6031value is usually 1 for most of simple statistics. 1 means it contains an 6032unsigned 64bit data. 6033 6034The ``offset`` field is the offset from the start of Data Block to the start of 6035the corresponding statistics data. 6036 6037The ``bucket_size`` field is used as a parameter for histogram statistics data. 6038It is only used by linear histogram statistics data, specifying the size of a 6039bucket in the unit expressed by bits 4-11 of ``flags`` together with ``exponent``. 6040 6041The ``name`` field is the name string of the statistics data. The name string 6042starts at the end of ``struct kvm_stats_desc``. The maximum length including 6043the trailing ``'\0'``, is indicated by ``name_size`` in the header. 6044 6045The Stats Data block contains an array of 64-bit values in the same order 6046as the descriptors in Descriptors block. 6047 60484.134 KVM_GET_XSAVE2 6049-------------------- 6050 6051:Capability: KVM_CAP_XSAVE2 6052:Architectures: x86 6053:Type: vcpu ioctl 6054:Parameters: struct kvm_xsave (out) 6055:Returns: 0 on success, -1 on error 6056 6057 6058:: 6059 6060 struct kvm_xsave { 6061 __u32 region[1024]; 6062 __u32 extra[0]; 6063 }; 6064 6065This ioctl would copy current vcpu's xsave struct to the userspace. It 6066copies as many bytes as are returned by KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2) 6067when invoked on the vm file descriptor. The size value returned by 6068KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2) will always be at least 4096. 6069Currently, it is only greater than 4096 if a dynamic feature has been 6070enabled with ``arch_prctl()``, but this may change in the future. 6071 6072The offsets of the state save areas in struct kvm_xsave follow the contents 6073of CPUID leaf 0xD on the host. 6074 60754.135 KVM_XEN_HVM_EVTCHN_SEND 6076----------------------------- 6077 6078:Capability: KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_EVTCHN_SEND 6079:Architectures: x86 6080:Type: vm ioctl 6081:Parameters: struct kvm_irq_routing_xen_evtchn 6082:Returns: 0 on success, < 0 on error 6083 6084 6085:: 6086 6087 struct kvm_irq_routing_xen_evtchn { 6088 __u32 port; 6089 __u32 vcpu; 6090 __u32 priority; 6091 }; 6092 6093This ioctl injects an event channel interrupt directly to the guest vCPU. 6094 60954.136 KVM_S390_PV_CPU_COMMAND 6096----------------------------- 6097 6098:Capability: KVM_CAP_S390_PROTECTED_DUMP 6099:Architectures: s390 6100:Type: vcpu ioctl 6101:Parameters: none 6102:Returns: 0 on success, < 0 on error 6103 6104This ioctl closely mirrors `KVM_S390_PV_COMMAND` but handles requests 6105for vcpus. It re-uses the kvm_s390_pv_dmp struct and hence also shares 6106the command ids. 6107 6108**command:** 6109 6110KVM_PV_DUMP 6111 Presents an API that provides calls which facilitate dumping a vcpu 6112 of a protected VM. 6113 6114**subcommand:** 6115 6116KVM_PV_DUMP_CPU 6117 Provides encrypted dump data like register values. 6118 The length of the returned data is provided by uv_info.guest_cpu_stor_len. 6119 61204.137 KVM_S390_ZPCI_OP 6121---------------------- 6122 6123:Capability: KVM_CAP_S390_ZPCI_OP 6124:Architectures: s390 6125:Type: vm ioctl 6126:Parameters: struct kvm_s390_zpci_op (in) 6127:Returns: 0 on success, <0 on error 6128 6129Used to manage hardware-assisted virtualization features for zPCI devices. 6130 6131Parameters are specified via the following structure:: 6132 6133 struct kvm_s390_zpci_op { 6134 /* in */ 6135 __u32 fh; /* target device */ 6136 __u8 op; /* operation to perform */ 6137 __u8 pad[3]; 6138 union { 6139 /* for KVM_S390_ZPCIOP_REG_AEN */ 6140 struct { 6141 __u64 ibv; /* Guest addr of interrupt bit vector */ 6142 __u64 sb; /* Guest addr of summary bit */ 6143 __u32 flags; 6144 __u32 noi; /* Number of interrupts */ 6145 __u8 isc; /* Guest interrupt subclass */ 6146 __u8 sbo; /* Offset of guest summary bit vector */ 6147 __u16 pad; 6148 } reg_aen; 6149 __u64 reserved[8]; 6150 } u; 6151 }; 6152 6153The type of operation is specified in the "op" field. 6154KVM_S390_ZPCIOP_REG_AEN is used to register the VM for adapter event 6155notification interpretation, which will allow firmware delivery of adapter 6156events directly to the vm, with KVM providing a backup delivery mechanism; 6157KVM_S390_ZPCIOP_DEREG_AEN is used to subsequently disable interpretation of 6158adapter event notifications. 6159 6160The target zPCI function must also be specified via the "fh" field. For the 6161KVM_S390_ZPCIOP_REG_AEN operation, additional information to establish firmware 6162delivery must be provided via the "reg_aen" struct. 6163 6164The "pad" and "reserved" fields may be used for future extensions and should be 6165set to 0s by userspace. 6166 61674.138 KVM_ARM_SET_COUNTER_OFFSET 6168-------------------------------- 6169 6170:Capability: KVM_CAP_COUNTER_OFFSET 6171:Architectures: arm64 6172:Type: vm ioctl 6173:Parameters: struct kvm_arm_counter_offset (in) 6174:Returns: 0 on success, < 0 on error 6175 6176This capability indicates that userspace is able to apply a single VM-wide 6177offset to both the virtual and physical counters as viewed by the guest 6178using the KVM_ARM_SET_CNT_OFFSET ioctl and the following data structure: 6179 6180:: 6181 6182 struct kvm_arm_counter_offset { 6183 __u64 counter_offset; 6184 __u64 reserved; 6185 }; 6186 6187The offset describes a number of counter cycles that are subtracted from 6188both virtual and physical counter views (similar to the effects of the 6189CNTVOFF_EL2 and CNTPOFF_EL2 system registers, but only global). The offset 6190always applies to all vcpus (already created or created after this ioctl) 6191for this VM. 6192 6193It is userspace's responsibility to compute the offset based, for example, 6194on previous values of the guest counters. 6195 6196Any value other than 0 for the "reserved" field may result in an error 6197(-EINVAL) being returned. This ioctl can also return -EBUSY if any vcpu 6198ioctl is issued concurrently. 6199 6200Note that using this ioctl results in KVM ignoring subsequent userspace 6201writes to the CNTVCT_EL0 and CNTPCT_EL0 registers using the SET_ONE_REG 6202interface. No error will be returned, but the resulting offset will not be 6203applied. 6204 6205.. _KVM_ARM_GET_REG_WRITABLE_MASKS: 6206 62074.139 KVM_ARM_GET_REG_WRITABLE_MASKS 6208------------------------------------ 6209 6210:Capability: KVM_CAP_ARM_SUPPORTED_REG_MASK_RANGES 6211:Architectures: arm64 6212:Type: vm ioctl 6213:Parameters: struct reg_mask_range (in/out) 6214:Returns: 0 on success, < 0 on error 6215 6216 6217:: 6218 6219 #define KVM_ARM_FEATURE_ID_RANGE 0 6220 #define KVM_ARM_FEATURE_ID_RANGE_SIZE (3 * 8 * 8) 6221 6222 struct reg_mask_range { 6223 __u64 addr; /* Pointer to mask array */ 6224 __u32 range; /* Requested range */ 6225 __u32 reserved[13]; 6226 }; 6227 6228This ioctl copies the writable masks for a selected range of registers to 6229userspace. 6230 6231The ``addr`` field is a pointer to the destination array where KVM copies 6232the writable masks. 6233 6234The ``range`` field indicates the requested range of registers. 6235``KVM_CHECK_EXTENSION`` for the ``KVM_CAP_ARM_SUPPORTED_REG_MASK_RANGES`` 6236capability returns the supported ranges, expressed as a set of flags. Each 6237flag's bit index represents a possible value for the ``range`` field. 6238All other values are reserved for future use and KVM may return an error. 6239 6240The ``reserved[13]`` array is reserved for future use and should be 0, or 6241KVM may return an error. 6242 6243KVM_ARM_FEATURE_ID_RANGE (0) 6244^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 6245 6246The Feature ID range is defined as the AArch64 System register space with 6247op0==3, op1=={0, 1, 3}, CRn==0, CRm=={0-7}, op2=={0-7}. 6248 6249The mask returned array pointed to by ``addr`` is indexed by the macro 6250``ARM64_FEATURE_ID_RANGE_IDX(op0, op1, crn, crm, op2)``, allowing userspace 6251to know what fields can be changed for the system register described by 6252``op0, op1, crn, crm, op2``. KVM rejects ID register values that describe a 6253superset of the features supported by the system. 6254 62554.140 KVM_SET_USER_MEMORY_REGION2 6256--------------------------------- 6257 6258:Capability: KVM_CAP_USER_MEMORY2 6259:Architectures: all 6260:Type: vm ioctl 6261:Parameters: struct kvm_userspace_memory_region2 (in) 6262:Returns: 0 on success, -1 on error 6263 6264KVM_SET_USER_MEMORY_REGION2 is an extension to KVM_SET_USER_MEMORY_REGION that 6265allows mapping guest_memfd memory into a guest. All fields shared with 6266KVM_SET_USER_MEMORY_REGION identically. Userspace can set KVM_MEM_GUEST_MEMFD 6267in flags to have KVM bind the memory region to a given guest_memfd range of 6268[guest_memfd_offset, guest_memfd_offset + memory_size]. The target guest_memfd 6269must point at a file created via KVM_CREATE_GUEST_MEMFD on the current VM, and 6270the target range must not be bound to any other memory region. All standard 6271bounds checks apply (use common sense). 6272 6273:: 6274 6275 struct kvm_userspace_memory_region2 { 6276 __u32 slot; 6277 __u32 flags; 6278 __u64 guest_phys_addr; 6279 __u64 memory_size; /* bytes */ 6280 __u64 userspace_addr; /* start of the userspace allocated memory */ 6281 __u64 guest_memfd_offset; 6282 __u32 guest_memfd; 6283 __u32 pad1; 6284 __u64 pad2[14]; 6285 }; 6286 6287A KVM_MEM_GUEST_MEMFD region _must_ have a valid guest_memfd (private memory) and 6288userspace_addr (shared memory). However, "valid" for userspace_addr simply 6289means that the address itself must be a legal userspace address. The backing 6290mapping for userspace_addr is not required to be valid/populated at the time of 6291KVM_SET_USER_MEMORY_REGION2, e.g. shared memory can be lazily mapped/allocated 6292on-demand. 6293 6294When mapping a gfn into the guest, KVM selects shared vs. private, i.e consumes 6295userspace_addr vs. guest_memfd, based on the gfn's KVM_MEMORY_ATTRIBUTE_PRIVATE 6296state. At VM creation time, all memory is shared, i.e. the PRIVATE attribute 6297is '0' for all gfns. Userspace can control whether memory is shared/private by 6298toggling KVM_MEMORY_ATTRIBUTE_PRIVATE via KVM_SET_MEMORY_ATTRIBUTES as needed. 6299 6300S390: 6301^^^^^ 6302 6303Returns -EINVAL if the VM has the KVM_VM_S390_UCONTROL flag set. 6304Returns -EINVAL if called on a protected VM. 6305 63064.141 KVM_SET_MEMORY_ATTRIBUTES 6307------------------------------- 6308 6309:Capability: KVM_CAP_MEMORY_ATTRIBUTES 6310:Architectures: x86 6311:Type: vm ioctl 6312:Parameters: struct kvm_memory_attributes (in) 6313:Returns: 0 on success, <0 on error 6314 6315KVM_SET_MEMORY_ATTRIBUTES allows userspace to set memory attributes for a range 6316of guest physical memory. 6317 6318:: 6319 6320 struct kvm_memory_attributes { 6321 __u64 address; 6322 __u64 size; 6323 __u64 attributes; 6324 __u64 flags; 6325 }; 6326 6327 #define KVM_MEMORY_ATTRIBUTE_PRIVATE (1ULL << 3) 6328 6329The address and size must be page aligned. The supported attributes can be 6330retrieved via ioctl(KVM_CHECK_EXTENSION) on KVM_CAP_MEMORY_ATTRIBUTES. If 6331executed on a VM, KVM_CAP_MEMORY_ATTRIBUTES precisely returns the attributes 6332supported by that VM. If executed at system scope, KVM_CAP_MEMORY_ATTRIBUTES 6333returns all attributes supported by KVM. The only attribute defined at this 6334time is KVM_MEMORY_ATTRIBUTE_PRIVATE, which marks the associated gfn as being 6335guest private memory. 6336 6337Note, there is no "get" API. Userspace is responsible for explicitly tracking 6338the state of a gfn/page as needed. 6339 6340The "flags" field is reserved for future extensions and must be '0'. 6341 63424.142 KVM_CREATE_GUEST_MEMFD 6343---------------------------- 6344 6345:Capability: KVM_CAP_GUEST_MEMFD 6346:Architectures: none 6347:Type: vm ioctl 6348:Parameters: struct kvm_create_guest_memfd(in) 6349:Returns: A file descriptor on success, <0 on error 6350 6351KVM_CREATE_GUEST_MEMFD creates an anonymous file and returns a file descriptor 6352that refers to it. guest_memfd files are roughly analogous to files created 6353via memfd_create(), e.g. guest_memfd files live in RAM, have volatile storage, 6354and are automatically released when the last reference is dropped. Unlike 6355"regular" memfd_create() files, guest_memfd files are bound to their owning 6356virtual machine (see below), cannot be mapped, read, or written by userspace, 6357and cannot be resized (guest_memfd files do however support PUNCH_HOLE). 6358 6359:: 6360 6361 struct kvm_create_guest_memfd { 6362 __u64 size; 6363 __u64 flags; 6364 __u64 reserved[6]; 6365 }; 6366 6367Conceptually, the inode backing a guest_memfd file represents physical memory, 6368i.e. is coupled to the virtual machine as a thing, not to a "struct kvm". The 6369file itself, which is bound to a "struct kvm", is that instance's view of the 6370underlying memory, e.g. effectively provides the translation of guest addresses 6371to host memory. This allows for use cases where multiple KVM structures are 6372used to manage a single virtual machine, e.g. when performing intrahost 6373migration of a virtual machine. 6374 6375KVM currently only supports mapping guest_memfd via KVM_SET_USER_MEMORY_REGION2, 6376and more specifically via the guest_memfd and guest_memfd_offset fields in 6377"struct kvm_userspace_memory_region2", where guest_memfd_offset is the offset 6378into the guest_memfd instance. For a given guest_memfd file, there can be at 6379most one mapping per page, i.e. binding multiple memory regions to a single 6380guest_memfd range is not allowed (any number of memory regions can be bound to 6381a single guest_memfd file, but the bound ranges must not overlap). 6382 6383See KVM_SET_USER_MEMORY_REGION2 for additional details. 6384 63854.143 KVM_PRE_FAULT_MEMORY 6386--------------------------- 6387 6388:Capability: KVM_CAP_PRE_FAULT_MEMORY 6389:Architectures: none 6390:Type: vcpu ioctl 6391:Parameters: struct kvm_pre_fault_memory (in/out) 6392:Returns: 0 if at least one page is processed, < 0 on error 6393 6394Errors: 6395 6396 ========== =============================================================== 6397 EINVAL The specified `gpa` and `size` were invalid (e.g. not 6398 page aligned, causes an overflow, or size is zero). 6399 ENOENT The specified `gpa` is outside defined memslots. 6400 EINTR An unmasked signal is pending and no page was processed. 6401 EFAULT The parameter address was invalid. 6402 EOPNOTSUPP Mapping memory for a GPA is unsupported by the 6403 hypervisor, and/or for the current vCPU state/mode. 6404 EIO unexpected error conditions (also causes a WARN) 6405 ========== =============================================================== 6406 6407:: 6408 6409 struct kvm_pre_fault_memory { 6410 /* in/out */ 6411 __u64 gpa; 6412 __u64 size; 6413 /* in */ 6414 __u64 flags; 6415 __u64 padding[5]; 6416 }; 6417 6418KVM_PRE_FAULT_MEMORY populates KVM's stage-2 page tables used to map memory 6419for the current vCPU state. KVM maps memory as if the vCPU generated a 6420stage-2 read page fault, e.g. faults in memory as needed, but doesn't break 6421CoW. However, KVM does not mark any newly created stage-2 PTE as Accessed. 6422 6423In the case of confidential VM types where there is an initial set up of 6424private guest memory before the guest is 'finalized'/measured, this ioctl 6425should only be issued after completing all the necessary setup to put the 6426guest into a 'finalized' state so that the above semantics can be reliably 6427ensured. 6428 6429In some cases, multiple vCPUs might share the page tables. In this 6430case, the ioctl can be called in parallel. 6431 6432When the ioctl returns, the input values are updated to point to the 6433remaining range. If `size` > 0 on return, the caller can just issue 6434the ioctl again with the same `struct kvm_map_memory` argument. 6435 6436Shadow page tables cannot support this ioctl because they 6437are indexed by virtual address or nested guest physical address. 6438Calling this ioctl when the guest is using shadow page tables (for 6439example because it is running a nested guest with nested page tables) 6440will fail with `EOPNOTSUPP` even if `KVM_CHECK_EXTENSION` reports 6441the capability to be present. 6442 6443`flags` must currently be zero. 6444 6445 6446.. _kvm_run: 6447 64485. The kvm_run structure 6449======================== 6450 6451Application code obtains a pointer to the kvm_run structure by 6452mmap()ing a vcpu fd. From that point, application code can control 6453execution by changing fields in kvm_run prior to calling the KVM_RUN 6454ioctl, and obtain information about the reason KVM_RUN returned by 6455looking up structure members. 6456 6457:: 6458 6459 struct kvm_run { 6460 /* in */ 6461 __u8 request_interrupt_window; 6462 6463Request that KVM_RUN return when it becomes possible to inject external 6464interrupts into the guest. Useful in conjunction with KVM_INTERRUPT. 6465 6466:: 6467 6468 __u8 immediate_exit; 6469 6470This field is polled once when KVM_RUN starts; if non-zero, KVM_RUN 6471exits immediately, returning -EINTR. In the common scenario where a 6472signal is used to "kick" a VCPU out of KVM_RUN, this field can be used 6473to avoid usage of KVM_SET_SIGNAL_MASK, which has worse scalability. 6474Rather than blocking the signal outside KVM_RUN, userspace can set up 6475a signal handler that sets run->immediate_exit to a non-zero value. 6476 6477This field is ignored if KVM_CAP_IMMEDIATE_EXIT is not available. 6478 6479:: 6480 6481 __u8 padding1[6]; 6482 6483 /* out */ 6484 __u32 exit_reason; 6485 6486When KVM_RUN has returned successfully (return value 0), this informs 6487application code why KVM_RUN has returned. Allowable values for this 6488field are detailed below. 6489 6490:: 6491 6492 __u8 ready_for_interrupt_injection; 6493 6494If request_interrupt_window has been specified, this field indicates 6495an interrupt can be injected now with KVM_INTERRUPT. 6496 6497:: 6498 6499 __u8 if_flag; 6500 6501The value of the current interrupt flag. Only valid if in-kernel 6502local APIC is not used. 6503 6504:: 6505 6506 __u16 flags; 6507 6508More architecture-specific flags detailing state of the VCPU that may 6509affect the device's behavior. Current defined flags:: 6510 6511 /* x86, set if the VCPU is in system management mode */ 6512 #define KVM_RUN_X86_SMM (1 << 0) 6513 /* x86, set if bus lock detected in VM */ 6514 #define KVM_RUN_X86_BUS_LOCK (1 << 1) 6515 /* x86, set if the VCPU is executing a nested (L2) guest */ 6516 #define KVM_RUN_X86_GUEST_MODE (1 << 2) 6517 6518 /* arm64, set for KVM_EXIT_DEBUG */ 6519 #define KVM_DEBUG_ARCH_HSR_HIGH_VALID (1 << 0) 6520 6521:: 6522 6523 /* in (pre_kvm_run), out (post_kvm_run) */ 6524 __u64 cr8; 6525 6526The value of the cr8 register. Only valid if in-kernel local APIC is 6527not used. Both input and output. 6528 6529:: 6530 6531 __u64 apic_base; 6532 6533The value of the APIC BASE msr. Only valid if in-kernel local 6534APIC is not used. Both input and output. 6535 6536:: 6537 6538 union { 6539 /* KVM_EXIT_UNKNOWN */ 6540 struct { 6541 __u64 hardware_exit_reason; 6542 } hw; 6543 6544If exit_reason is KVM_EXIT_UNKNOWN, the vcpu has exited due to unknown 6545reasons. Further architecture-specific information is available in 6546hardware_exit_reason. 6547 6548:: 6549 6550 /* KVM_EXIT_FAIL_ENTRY */ 6551 struct { 6552 __u64 hardware_entry_failure_reason; 6553 __u32 cpu; /* if KVM_LAST_CPU */ 6554 } fail_entry; 6555 6556If exit_reason is KVM_EXIT_FAIL_ENTRY, the vcpu could not be run due 6557to unknown reasons. Further architecture-specific information is 6558available in hardware_entry_failure_reason. 6559 6560:: 6561 6562 /* KVM_EXIT_EXCEPTION */ 6563 struct { 6564 __u32 exception; 6565 __u32 error_code; 6566 } ex; 6567 6568Unused. 6569 6570:: 6571 6572 /* KVM_EXIT_IO */ 6573 struct { 6574 #define KVM_EXIT_IO_IN 0 6575 #define KVM_EXIT_IO_OUT 1 6576 __u8 direction; 6577 __u8 size; /* bytes */ 6578 __u16 port; 6579 __u32 count; 6580 __u64 data_offset; /* relative to kvm_run start */ 6581 } io; 6582 6583If exit_reason is KVM_EXIT_IO, then the vcpu has 6584executed a port I/O instruction which could not be satisfied by kvm. 6585data_offset describes where the data is located (KVM_EXIT_IO_OUT) or 6586where kvm expects application code to place the data for the next 6587KVM_RUN invocation (KVM_EXIT_IO_IN). Data format is a packed array. 6588 6589:: 6590 6591 /* KVM_EXIT_DEBUG */ 6592 struct { 6593 struct kvm_debug_exit_arch arch; 6594 } debug; 6595 6596If the exit_reason is KVM_EXIT_DEBUG, then a vcpu is processing a debug event 6597for which architecture specific information is returned. 6598 6599:: 6600 6601 /* KVM_EXIT_MMIO */ 6602 struct { 6603 __u64 phys_addr; 6604 __u8 data[8]; 6605 __u32 len; 6606 __u8 is_write; 6607 } mmio; 6608 6609If exit_reason is KVM_EXIT_MMIO, then the vcpu has 6610executed a memory-mapped I/O instruction which could not be satisfied 6611by kvm. The 'data' member contains the written data if 'is_write' is 6612true, and should be filled by application code otherwise. 6613 6614The 'data' member contains, in its first 'len' bytes, the value as it would 6615appear if the VCPU performed a load or store of the appropriate width directly 6616to the byte array. 6617 6618.. note:: 6619 6620 For KVM_EXIT_IO, KVM_EXIT_MMIO, KVM_EXIT_OSI, KVM_EXIT_PAPR, KVM_EXIT_XEN, 6621 KVM_EXIT_EPR, KVM_EXIT_X86_RDMSR and KVM_EXIT_X86_WRMSR the corresponding 6622 operations are complete (and guest state is consistent) only after userspace 6623 has re-entered the kernel with KVM_RUN. The kernel side will first finish 6624 incomplete operations and then check for pending signals. 6625 6626 The pending state of the operation is not preserved in state which is 6627 visible to userspace, thus userspace should ensure that the operation is 6628 completed before performing a live migration. Userspace can re-enter the 6629 guest with an unmasked signal pending or with the immediate_exit field set 6630 to complete pending operations without allowing any further instructions 6631 to be executed. 6632 6633:: 6634 6635 /* KVM_EXIT_HYPERCALL */ 6636 struct { 6637 __u64 nr; 6638 __u64 args[6]; 6639 __u64 ret; 6640 __u64 flags; 6641 } hypercall; 6642 6643 6644It is strongly recommended that userspace use ``KVM_EXIT_IO`` (x86) or 6645``KVM_EXIT_MMIO`` (all except s390) to implement functionality that 6646requires a guest to interact with host userspace. 6647 6648.. note:: KVM_EXIT_IO is significantly faster than KVM_EXIT_MMIO. 6649 6650For arm64: 6651---------- 6652 6653SMCCC exits can be enabled depending on the configuration of the SMCCC 6654filter. See the Documentation/virt/kvm/devices/vm.rst 6655``KVM_ARM_SMCCC_FILTER`` for more details. 6656 6657``nr`` contains the function ID of the guest's SMCCC call. Userspace is 6658expected to use the ``KVM_GET_ONE_REG`` ioctl to retrieve the call 6659parameters from the vCPU's GPRs. 6660 6661Definition of ``flags``: 6662 - ``KVM_HYPERCALL_EXIT_SMC``: Indicates that the guest used the SMC 6663 conduit to initiate the SMCCC call. If this bit is 0 then the guest 6664 used the HVC conduit for the SMCCC call. 6665 6666 - ``KVM_HYPERCALL_EXIT_16BIT``: Indicates that the guest used a 16bit 6667 instruction to initiate the SMCCC call. If this bit is 0 then the 6668 guest used a 32bit instruction. An AArch64 guest always has this 6669 bit set to 0. 6670 6671At the point of exit, PC points to the instruction immediately following 6672the trapping instruction. 6673 6674:: 6675 6676 /* KVM_EXIT_TPR_ACCESS */ 6677 struct { 6678 __u64 rip; 6679 __u32 is_write; 6680 __u32 pad; 6681 } tpr_access; 6682 6683To be documented (KVM_TPR_ACCESS_REPORTING). 6684 6685:: 6686 6687 /* KVM_EXIT_S390_SIEIC */ 6688 struct { 6689 __u8 icptcode; 6690 __u64 mask; /* psw upper half */ 6691 __u64 addr; /* psw lower half */ 6692 __u16 ipa; 6693 __u32 ipb; 6694 } s390_sieic; 6695 6696s390 specific. 6697 6698:: 6699 6700 /* KVM_EXIT_S390_RESET */ 6701 #define KVM_S390_RESET_POR 1 6702 #define KVM_S390_RESET_CLEAR 2 6703 #define KVM_S390_RESET_SUBSYSTEM 4 6704 #define KVM_S390_RESET_CPU_INIT 8 6705 #define KVM_S390_RESET_IPL 16 6706 __u64 s390_reset_flags; 6707 6708s390 specific. 6709 6710:: 6711 6712 /* KVM_EXIT_S390_UCONTROL */ 6713 struct { 6714 __u64 trans_exc_code; 6715 __u32 pgm_code; 6716 } s390_ucontrol; 6717 6718s390 specific. A page fault has occurred for a user controlled virtual 6719machine (KVM_VM_S390_UNCONTROL) on its host page table that cannot be 6720resolved by the kernel. 6721The program code and the translation exception code that were placed 6722in the cpu's lowcore are presented here as defined by the z Architecture 6723Principles of Operation Book in the Chapter for Dynamic Address Translation 6724(DAT) 6725 6726:: 6727 6728 /* KVM_EXIT_DCR */ 6729 struct { 6730 __u32 dcrn; 6731 __u32 data; 6732 __u8 is_write; 6733 } dcr; 6734 6735Deprecated - was used for 440 KVM. 6736 6737:: 6738 6739 /* KVM_EXIT_OSI */ 6740 struct { 6741 __u64 gprs[32]; 6742 } osi; 6743 6744MOL uses a special hypercall interface it calls 'OSI'. To enable it, we catch 6745hypercalls and exit with this exit struct that contains all the guest gprs. 6746 6747If exit_reason is KVM_EXIT_OSI, then the vcpu has triggered such a hypercall. 6748Userspace can now handle the hypercall and when it's done modify the gprs as 6749necessary. Upon guest entry all guest GPRs will then be replaced by the values 6750in this struct. 6751 6752:: 6753 6754 /* KVM_EXIT_PAPR_HCALL */ 6755 struct { 6756 __u64 nr; 6757 __u64 ret; 6758 __u64 args[9]; 6759 } papr_hcall; 6760 6761This is used on 64-bit PowerPC when emulating a pSeries partition, 6762e.g. with the 'pseries' machine type in qemu. It occurs when the 6763guest does a hypercall using the 'sc 1' instruction. The 'nr' field 6764contains the hypercall number (from the guest R3), and 'args' contains 6765the arguments (from the guest R4 - R12). Userspace should put the 6766return code in 'ret' and any extra returned values in args[]. 6767The possible hypercalls are defined in the Power Architecture Platform 6768Requirements (PAPR) document available from www.power.org (free 6769developer registration required to access it). 6770 6771:: 6772 6773 /* KVM_EXIT_S390_TSCH */ 6774 struct { 6775 __u16 subchannel_id; 6776 __u16 subchannel_nr; 6777 __u32 io_int_parm; 6778 __u32 io_int_word; 6779 __u32 ipb; 6780 __u8 dequeued; 6781 } s390_tsch; 6782 6783s390 specific. This exit occurs when KVM_CAP_S390_CSS_SUPPORT has been enabled 6784and TEST SUBCHANNEL was intercepted. If dequeued is set, a pending I/O 6785interrupt for the target subchannel has been dequeued and subchannel_id, 6786subchannel_nr, io_int_parm and io_int_word contain the parameters for that 6787interrupt. ipb is needed for instruction parameter decoding. 6788 6789:: 6790 6791 /* KVM_EXIT_EPR */ 6792 struct { 6793 __u32 epr; 6794 } epr; 6795 6796On FSL BookE PowerPC chips, the interrupt controller has a fast patch 6797interrupt acknowledge path to the core. When the core successfully 6798delivers an interrupt, it automatically populates the EPR register with 6799the interrupt vector number and acknowledges the interrupt inside 6800the interrupt controller. 6801 6802In case the interrupt controller lives in user space, we need to do 6803the interrupt acknowledge cycle through it to fetch the next to be 6804delivered interrupt vector using this exit. 6805 6806It gets triggered whenever both KVM_CAP_PPC_EPR are enabled and an 6807external interrupt has just been delivered into the guest. User space 6808should put the acknowledged interrupt vector into the 'epr' field. 6809 6810:: 6811 6812 /* KVM_EXIT_SYSTEM_EVENT */ 6813 struct { 6814 #define KVM_SYSTEM_EVENT_SHUTDOWN 1 6815 #define KVM_SYSTEM_EVENT_RESET 2 6816 #define KVM_SYSTEM_EVENT_CRASH 3 6817 #define KVM_SYSTEM_EVENT_WAKEUP 4 6818 #define KVM_SYSTEM_EVENT_SUSPEND 5 6819 #define KVM_SYSTEM_EVENT_SEV_TERM 6 6820 __u32 type; 6821 __u32 ndata; 6822 __u64 data[16]; 6823 } system_event; 6824 6825If exit_reason is KVM_EXIT_SYSTEM_EVENT then the vcpu has triggered 6826a system-level event using some architecture specific mechanism (hypercall 6827or some special instruction). In case of ARM64, this is triggered using 6828HVC instruction based PSCI call from the vcpu. 6829 6830The 'type' field describes the system-level event type. 6831Valid values for 'type' are: 6832 6833 - KVM_SYSTEM_EVENT_SHUTDOWN -- the guest has requested a shutdown of the 6834 VM. Userspace is not obliged to honour this, and if it does honour 6835 this does not need to destroy the VM synchronously (ie it may call 6836 KVM_RUN again before shutdown finally occurs). 6837 - KVM_SYSTEM_EVENT_RESET -- the guest has requested a reset of the VM. 6838 As with SHUTDOWN, userspace can choose to ignore the request, or 6839 to schedule the reset to occur in the future and may call KVM_RUN again. 6840 - KVM_SYSTEM_EVENT_CRASH -- the guest crash occurred and the guest 6841 has requested a crash condition maintenance. Userspace can choose 6842 to ignore the request, or to gather VM memory core dump and/or 6843 reset/shutdown of the VM. 6844 - KVM_SYSTEM_EVENT_SEV_TERM -- an AMD SEV guest requested termination. 6845 The guest physical address of the guest's GHCB is stored in `data[0]`. 6846 - KVM_SYSTEM_EVENT_WAKEUP -- the exiting vCPU is in a suspended state and 6847 KVM has recognized a wakeup event. Userspace may honor this event by 6848 marking the exiting vCPU as runnable, or deny it and call KVM_RUN again. 6849 - KVM_SYSTEM_EVENT_SUSPEND -- the guest has requested a suspension of 6850 the VM. 6851 6852If KVM_CAP_SYSTEM_EVENT_DATA is present, the 'data' field can contain 6853architecture specific information for the system-level event. Only 6854the first `ndata` items (possibly zero) of the data array are valid. 6855 6856 - for arm64, data[0] is set to KVM_SYSTEM_EVENT_RESET_FLAG_PSCI_RESET2 if 6857 the guest issued a SYSTEM_RESET2 call according to v1.1 of the PSCI 6858 specification. 6859 6860 - for arm64, data[0] is set to KVM_SYSTEM_EVENT_SHUTDOWN_FLAG_PSCI_OFF2 6861 if the guest issued a SYSTEM_OFF2 call according to v1.3 of the PSCI 6862 specification. 6863 6864 - for RISC-V, data[0] is set to the value of the second argument of the 6865 ``sbi_system_reset`` call. 6866 6867Previous versions of Linux defined a `flags` member in this struct. The 6868field is now aliased to `data[0]`. Userspace can assume that it is only 6869written if ndata is greater than 0. 6870 6871For arm/arm64: 6872-------------- 6873 6874KVM_SYSTEM_EVENT_SUSPEND exits are enabled with the 6875KVM_CAP_ARM_SYSTEM_SUSPEND VM capability. If a guest invokes the PSCI 6876SYSTEM_SUSPEND function, KVM will exit to userspace with this event 6877type. 6878 6879It is the sole responsibility of userspace to implement the PSCI 6880SYSTEM_SUSPEND call according to ARM DEN0022D.b 5.19 "SYSTEM_SUSPEND". 6881KVM does not change the vCPU's state before exiting to userspace, so 6882the call parameters are left in-place in the vCPU registers. 6883 6884Userspace is _required_ to take action for such an exit. It must 6885either: 6886 6887 - Honor the guest request to suspend the VM. Userspace can request 6888 in-kernel emulation of suspension by setting the calling vCPU's 6889 state to KVM_MP_STATE_SUSPENDED. Userspace must configure the vCPU's 6890 state according to the parameters passed to the PSCI function when 6891 the calling vCPU is resumed. See ARM DEN0022D.b 5.19.1 "Intended use" 6892 for details on the function parameters. 6893 6894 - Deny the guest request to suspend the VM. See ARM DEN0022D.b 5.19.2 6895 "Caller responsibilities" for possible return values. 6896 6897Hibernation using the PSCI SYSTEM_OFF2 call is enabled when PSCI v1.3 6898is enabled. If a guest invokes the PSCI SYSTEM_OFF2 function, KVM will 6899exit to userspace with the KVM_SYSTEM_EVENT_SHUTDOWN event type and with 6900data[0] set to KVM_SYSTEM_EVENT_SHUTDOWN_FLAG_PSCI_OFF2. The only 6901supported hibernate type for the SYSTEM_OFF2 function is HIBERNATE_OFF. 6902 6903:: 6904 6905 /* KVM_EXIT_IOAPIC_EOI */ 6906 struct { 6907 __u8 vector; 6908 } eoi; 6909 6910Indicates that the VCPU's in-kernel local APIC received an EOI for a 6911level-triggered IOAPIC interrupt. This exit only triggers when the 6912IOAPIC is implemented in userspace (i.e. KVM_CAP_SPLIT_IRQCHIP is enabled); 6913the userspace IOAPIC should process the EOI and retrigger the interrupt if 6914it is still asserted. Vector is the LAPIC interrupt vector for which the 6915EOI was received. 6916 6917:: 6918 6919 struct kvm_hyperv_exit { 6920 #define KVM_EXIT_HYPERV_SYNIC 1 6921 #define KVM_EXIT_HYPERV_HCALL 2 6922 #define KVM_EXIT_HYPERV_SYNDBG 3 6923 __u32 type; 6924 __u32 pad1; 6925 union { 6926 struct { 6927 __u32 msr; 6928 __u32 pad2; 6929 __u64 control; 6930 __u64 evt_page; 6931 __u64 msg_page; 6932 } synic; 6933 struct { 6934 __u64 input; 6935 __u64 result; 6936 __u64 params[2]; 6937 } hcall; 6938 struct { 6939 __u32 msr; 6940 __u32 pad2; 6941 __u64 control; 6942 __u64 status; 6943 __u64 send_page; 6944 __u64 recv_page; 6945 __u64 pending_page; 6946 } syndbg; 6947 } u; 6948 }; 6949 /* KVM_EXIT_HYPERV */ 6950 struct kvm_hyperv_exit hyperv; 6951 6952Indicates that the VCPU exits into userspace to process some tasks 6953related to Hyper-V emulation. 6954 6955Valid values for 'type' are: 6956 6957 - KVM_EXIT_HYPERV_SYNIC -- synchronously notify user-space about 6958 6959Hyper-V SynIC state change. Notification is used to remap SynIC 6960event/message pages and to enable/disable SynIC messages/events processing 6961in userspace. 6962 6963 - KVM_EXIT_HYPERV_SYNDBG -- synchronously notify user-space about 6964 6965Hyper-V Synthetic debugger state change. Notification is used to either update 6966the pending_page location or to send a control command (send the buffer located 6967in send_page or recv a buffer to recv_page). 6968 6969:: 6970 6971 /* KVM_EXIT_ARM_NISV */ 6972 struct { 6973 __u64 esr_iss; 6974 __u64 fault_ipa; 6975 } arm_nisv; 6976 6977Used on arm64 systems. If a guest accesses memory not in a memslot, 6978KVM will typically return to userspace and ask it to do MMIO emulation on its 6979behalf. However, for certain classes of instructions, no instruction decode 6980(direction, length of memory access) is provided, and fetching and decoding 6981the instruction from the VM is overly complicated to live in the kernel. 6982 6983Historically, when this situation occurred, KVM would print a warning and kill 6984the VM. KVM assumed that if the guest accessed non-memslot memory, it was 6985trying to do I/O, which just couldn't be emulated, and the warning message was 6986phrased accordingly. However, what happened more often was that a guest bug 6987caused access outside the guest memory areas which should lead to a more 6988meaningful warning message and an external abort in the guest, if the access 6989did not fall within an I/O window. 6990 6991Userspace implementations can query for KVM_CAP_ARM_NISV_TO_USER, and enable 6992this capability at VM creation. Once this is done, these types of errors will 6993instead return to userspace with KVM_EXIT_ARM_NISV, with the valid bits from 6994the ESR_EL2 in the esr_iss field, and the faulting IPA in the fault_ipa field. 6995Userspace can either fix up the access if it's actually an I/O access by 6996decoding the instruction from guest memory (if it's very brave) and continue 6997executing the guest, or it can decide to suspend, dump, or restart the guest. 6998 6999Note that KVM does not skip the faulting instruction as it does for 7000KVM_EXIT_MMIO, but userspace has to emulate any change to the processing state 7001if it decides to decode and emulate the instruction. 7002 7003This feature isn't available to protected VMs, as userspace does not 7004have access to the state that is required to perform the emulation. 7005Instead, a data abort exception is directly injected in the guest. 7006Note that although KVM_CAP_ARM_NISV_TO_USER will be reported if 7007queried outside of a protected VM context, the feature will not be 7008exposed if queried on a protected VM file descriptor. 7009 7010:: 7011 7012 /* KVM_EXIT_X86_RDMSR / KVM_EXIT_X86_WRMSR */ 7013 struct { 7014 __u8 error; /* user -> kernel */ 7015 __u8 pad[7]; 7016 __u32 reason; /* kernel -> user */ 7017 __u32 index; /* kernel -> user */ 7018 __u64 data; /* kernel <-> user */ 7019 } msr; 7020 7021Used on x86 systems. When the VM capability KVM_CAP_X86_USER_SPACE_MSR is 7022enabled, MSR accesses to registers that would invoke a #GP by KVM kernel code 7023may instead trigger a KVM_EXIT_X86_RDMSR exit for reads and KVM_EXIT_X86_WRMSR 7024exit for writes. 7025 7026The "reason" field specifies why the MSR interception occurred. Userspace will 7027only receive MSR exits when a particular reason was requested during through 7028ENABLE_CAP. Currently valid exit reasons are: 7029 7030============================ ======================================== 7031 KVM_MSR_EXIT_REASON_UNKNOWN access to MSR that is unknown to KVM 7032 KVM_MSR_EXIT_REASON_INVAL access to invalid MSRs or reserved bits 7033 KVM_MSR_EXIT_REASON_FILTER access blocked by KVM_X86_SET_MSR_FILTER 7034============================ ======================================== 7035 7036For KVM_EXIT_X86_RDMSR, the "index" field tells userspace which MSR the guest 7037wants to read. To respond to this request with a successful read, userspace 7038writes the respective data into the "data" field and must continue guest 7039execution to ensure the read data is transferred into guest register state. 7040 7041If the RDMSR request was unsuccessful, userspace indicates that with a "1" in 7042the "error" field. This will inject a #GP into the guest when the VCPU is 7043executed again. 7044 7045For KVM_EXIT_X86_WRMSR, the "index" field tells userspace which MSR the guest 7046wants to write. Once finished processing the event, userspace must continue 7047vCPU execution. If the MSR write was unsuccessful, userspace also sets the 7048"error" field to "1". 7049 7050See KVM_X86_SET_MSR_FILTER for details on the interaction with MSR filtering. 7051 7052:: 7053 7054 7055 struct kvm_xen_exit { 7056 #define KVM_EXIT_XEN_HCALL 1 7057 __u32 type; 7058 union { 7059 struct { 7060 __u32 longmode; 7061 __u32 cpl; 7062 __u64 input; 7063 __u64 result; 7064 __u64 params[6]; 7065 } hcall; 7066 } u; 7067 }; 7068 /* KVM_EXIT_XEN */ 7069 struct kvm_hyperv_exit xen; 7070 7071Indicates that the VCPU exits into userspace to process some tasks 7072related to Xen emulation. 7073 7074Valid values for 'type' are: 7075 7076 - KVM_EXIT_XEN_HCALL -- synchronously notify user-space about Xen hypercall. 7077 Userspace is expected to place the hypercall result into the appropriate 7078 field before invoking KVM_RUN again. 7079 7080:: 7081 7082 /* KVM_EXIT_RISCV_SBI */ 7083 struct { 7084 unsigned long extension_id; 7085 unsigned long function_id; 7086 unsigned long args[6]; 7087 unsigned long ret[2]; 7088 } riscv_sbi; 7089 7090If exit reason is KVM_EXIT_RISCV_SBI then it indicates that the VCPU has 7091done a SBI call which is not handled by KVM RISC-V kernel module. The details 7092of the SBI call are available in 'riscv_sbi' member of kvm_run structure. The 7093'extension_id' field of 'riscv_sbi' represents SBI extension ID whereas the 7094'function_id' field represents function ID of given SBI extension. The 'args' 7095array field of 'riscv_sbi' represents parameters for the SBI call and 'ret' 7096array field represents return values. The userspace should update the return 7097values of SBI call before resuming the VCPU. For more details on RISC-V SBI 7098spec refer, https://github.com/riscv/riscv-sbi-doc. 7099 7100:: 7101 7102 /* KVM_EXIT_MEMORY_FAULT */ 7103 struct { 7104 #define KVM_MEMORY_EXIT_FLAG_PRIVATE (1ULL << 3) 7105 __u64 flags; 7106 __u64 gpa; 7107 __u64 size; 7108 } memory_fault; 7109 7110KVM_EXIT_MEMORY_FAULT indicates the vCPU has encountered a memory fault that 7111could not be resolved by KVM. The 'gpa' and 'size' (in bytes) describe the 7112guest physical address range [gpa, gpa + size) of the fault. The 'flags' field 7113describes properties of the faulting access that are likely pertinent: 7114 7115 - KVM_MEMORY_EXIT_FLAG_PRIVATE - When set, indicates the memory fault occurred 7116 on a private memory access. When clear, indicates the fault occurred on a 7117 shared access. 7118 7119Note! KVM_EXIT_MEMORY_FAULT is unique among all KVM exit reasons in that it 7120accompanies a return code of '-1', not '0'! errno will always be set to EFAULT 7121or EHWPOISON when KVM exits with KVM_EXIT_MEMORY_FAULT, userspace should assume 7122kvm_run.exit_reason is stale/undefined for all other error numbers. 7123 7124:: 7125 7126 /* KVM_EXIT_NOTIFY */ 7127 struct { 7128 #define KVM_NOTIFY_CONTEXT_INVALID (1 << 0) 7129 __u32 flags; 7130 } notify; 7131 7132Used on x86 systems. When the VM capability KVM_CAP_X86_NOTIFY_VMEXIT is 7133enabled, a VM exit generated if no event window occurs in VM non-root mode 7134for a specified amount of time. Once KVM_X86_NOTIFY_VMEXIT_USER is set when 7135enabling the cap, it would exit to userspace with the exit reason 7136KVM_EXIT_NOTIFY for further handling. The "flags" field contains more 7137detailed info. 7138 7139The valid value for 'flags' is: 7140 7141 - KVM_NOTIFY_CONTEXT_INVALID -- the VM context is corrupted and not valid 7142 in VMCS. It would run into unknown result if resume the target VM. 7143 7144:: 7145 7146 /* Fix the size of the union. */ 7147 char padding[256]; 7148 }; 7149 7150 /* 7151 * shared registers between kvm and userspace. 7152 * kvm_valid_regs specifies the register classes set by the host 7153 * kvm_dirty_regs specified the register classes dirtied by userspace 7154 * struct kvm_sync_regs is architecture specific, as well as the 7155 * bits for kvm_valid_regs and kvm_dirty_regs 7156 */ 7157 __u64 kvm_valid_regs; 7158 __u64 kvm_dirty_regs; 7159 union { 7160 struct kvm_sync_regs regs; 7161 char padding[SYNC_REGS_SIZE_BYTES]; 7162 } s; 7163 7164If KVM_CAP_SYNC_REGS is defined, these fields allow userspace to access 7165certain guest registers without having to call SET/GET_*REGS. Thus we can 7166avoid some system call overhead if userspace has to handle the exit. 7167Userspace can query the validity of the structure by checking 7168kvm_valid_regs for specific bits. These bits are architecture specific 7169and usually define the validity of a groups of registers. (e.g. one bit 7170for general purpose registers) 7171 7172Please note that the kernel is allowed to use the kvm_run structure as the 7173primary storage for certain register types. Therefore, the kernel may use the 7174values in kvm_run even if the corresponding bit in kvm_dirty_regs is not set. 7175 7176 7177.. _cap_enable: 7178 71796. Capabilities that can be enabled on vCPUs 7180============================================ 7181 7182There are certain capabilities that change the behavior of the virtual CPU or 7183the virtual machine when enabled. To enable them, please see 7184:ref:`KVM_ENABLE_CAP`. 7185 7186Below you can find a list of capabilities and what their effect on the vCPU or 7187the virtual machine is when enabling them. 7188 7189The following information is provided along with the description: 7190 7191 Architectures: 7192 which instruction set architectures provide this ioctl. 7193 x86 includes both i386 and x86_64. 7194 7195 Target: 7196 whether this is a per-vcpu or per-vm capability. 7197 7198 Parameters: 7199 what parameters are accepted by the capability. 7200 7201 Returns: 7202 the return value. General error numbers (EBADF, ENOMEM, EINVAL) 7203 are not detailed, but errors with specific meanings are. 7204 7205 72066.1 KVM_CAP_PPC_OSI 7207------------------- 7208 7209:Architectures: ppc 7210:Target: vcpu 7211:Parameters: none 7212:Returns: 0 on success; -1 on error 7213 7214This capability enables interception of OSI hypercalls that otherwise would 7215be treated as normal system calls to be injected into the guest. OSI hypercalls 7216were invented by Mac-on-Linux to have a standardized communication mechanism 7217between the guest and the host. 7218 7219When this capability is enabled, KVM_EXIT_OSI can occur. 7220 7221 72226.2 KVM_CAP_PPC_PAPR 7223-------------------- 7224 7225:Architectures: ppc 7226:Target: vcpu 7227:Parameters: none 7228:Returns: 0 on success; -1 on error 7229 7230This capability enables interception of PAPR hypercalls. PAPR hypercalls are 7231done using the hypercall instruction "sc 1". 7232 7233It also sets the guest privilege level to "supervisor" mode. Usually the guest 7234runs in "hypervisor" privilege mode with a few missing features. 7235 7236In addition to the above, it changes the semantics of SDR1. In this mode, the 7237HTAB address part of SDR1 contains an HVA instead of a GPA, as PAPR keeps the 7238HTAB invisible to the guest. 7239 7240When this capability is enabled, KVM_EXIT_PAPR_HCALL can occur. 7241 7242 72436.3 KVM_CAP_SW_TLB 7244------------------ 7245 7246:Architectures: ppc 7247:Target: vcpu 7248:Parameters: args[0] is the address of a struct kvm_config_tlb 7249:Returns: 0 on success; -1 on error 7250 7251:: 7252 7253 struct kvm_config_tlb { 7254 __u64 params; 7255 __u64 array; 7256 __u32 mmu_type; 7257 __u32 array_len; 7258 }; 7259 7260Configures the virtual CPU's TLB array, establishing a shared memory area 7261between userspace and KVM. The "params" and "array" fields are userspace 7262addresses of mmu-type-specific data structures. The "array_len" field is an 7263safety mechanism, and should be set to the size in bytes of the memory that 7264userspace has reserved for the array. It must be at least the size dictated 7265by "mmu_type" and "params". 7266 7267While KVM_RUN is active, the shared region is under control of KVM. Its 7268contents are undefined, and any modification by userspace results in 7269boundedly undefined behavior. 7270 7271On return from KVM_RUN, the shared region will reflect the current state of 7272the guest's TLB. If userspace makes any changes, it must call KVM_DIRTY_TLB 7273to tell KVM which entries have been changed, prior to calling KVM_RUN again 7274on this vcpu. 7275 7276For mmu types KVM_MMU_FSL_BOOKE_NOHV and KVM_MMU_FSL_BOOKE_HV: 7277 7278 - The "params" field is of type "struct kvm_book3e_206_tlb_params". 7279 - The "array" field points to an array of type "struct 7280 kvm_book3e_206_tlb_entry". 7281 - The array consists of all entries in the first TLB, followed by all 7282 entries in the second TLB. 7283 - Within a TLB, entries are ordered first by increasing set number. Within a 7284 set, entries are ordered by way (increasing ESEL). 7285 - The hash for determining set number in TLB0 is: (MAS2 >> 12) & (num_sets - 1) 7286 where "num_sets" is the tlb_sizes[] value divided by the tlb_ways[] value. 7287 - The tsize field of mas1 shall be set to 4K on TLB0, even though the 7288 hardware ignores this value for TLB0. 7289 72906.4 KVM_CAP_S390_CSS_SUPPORT 7291---------------------------- 7292 7293:Architectures: s390 7294:Target: vcpu 7295:Parameters: none 7296:Returns: 0 on success; -1 on error 7297 7298This capability enables support for handling of channel I/O instructions. 7299 7300TEST PENDING INTERRUPTION and the interrupt portion of TEST SUBCHANNEL are 7301handled in-kernel, while the other I/O instructions are passed to userspace. 7302 7303When this capability is enabled, KVM_EXIT_S390_TSCH will occur on TEST 7304SUBCHANNEL intercepts. 7305 7306Note that even though this capability is enabled per-vcpu, the complete 7307virtual machine is affected. 7308 73096.5 KVM_CAP_PPC_EPR 7310------------------- 7311 7312:Architectures: ppc 7313:Target: vcpu 7314:Parameters: args[0] defines whether the proxy facility is active 7315:Returns: 0 on success; -1 on error 7316 7317This capability enables or disables the delivery of interrupts through the 7318external proxy facility. 7319 7320When enabled (args[0] != 0), every time the guest gets an external interrupt 7321delivered, it automatically exits into user space with a KVM_EXIT_EPR exit 7322to receive the topmost interrupt vector. 7323 7324When disabled (args[0] == 0), behavior is as if this facility is unsupported. 7325 7326When this capability is enabled, KVM_EXIT_EPR can occur. 7327 73286.6 KVM_CAP_IRQ_MPIC 7329-------------------- 7330 7331:Architectures: ppc 7332:Parameters: args[0] is the MPIC device fd; 7333 args[1] is the MPIC CPU number for this vcpu 7334 7335This capability connects the vcpu to an in-kernel MPIC device. 7336 73376.7 KVM_CAP_IRQ_XICS 7338-------------------- 7339 7340:Architectures: ppc 7341:Target: vcpu 7342:Parameters: args[0] is the XICS device fd; 7343 args[1] is the XICS CPU number (server ID) for this vcpu 7344 7345This capability connects the vcpu to an in-kernel XICS device. 7346 73476.8 KVM_CAP_S390_IRQCHIP 7348------------------------ 7349 7350:Architectures: s390 7351:Target: vm 7352:Parameters: none 7353 7354This capability enables the in-kernel irqchip for s390. Please refer to 7355"4.24 KVM_CREATE_IRQCHIP" for details. 7356 73576.9 KVM_CAP_MIPS_FPU 7358-------------------- 7359 7360:Architectures: mips 7361:Target: vcpu 7362:Parameters: args[0] is reserved for future use (should be 0). 7363 7364This capability allows the use of the host Floating Point Unit by the guest. It 7365allows the Config1.FP bit to be set to enable the FPU in the guest. Once this is 7366done the ``KVM_REG_MIPS_FPR_*`` and ``KVM_REG_MIPS_FCR_*`` registers can be 7367accessed (depending on the current guest FPU register mode), and the Status.FR, 7368Config5.FRE bits are accessible via the KVM API and also from the guest, 7369depending on them being supported by the FPU. 7370 73716.10 KVM_CAP_MIPS_MSA 7372--------------------- 7373 7374:Architectures: mips 7375:Target: vcpu 7376:Parameters: args[0] is reserved for future use (should be 0). 7377 7378This capability allows the use of the MIPS SIMD Architecture (MSA) by the guest. 7379It allows the Config3.MSAP bit to be set to enable the use of MSA by the guest. 7380Once this is done the ``KVM_REG_MIPS_VEC_*`` and ``KVM_REG_MIPS_MSA_*`` 7381registers can be accessed, and the Config5.MSAEn bit is accessible via the 7382KVM API and also from the guest. 7383 73846.74 KVM_CAP_SYNC_REGS 7385---------------------- 7386 7387:Architectures: s390, x86 7388:Target: s390: always enabled, x86: vcpu 7389:Parameters: none 7390:Returns: x86: KVM_CHECK_EXTENSION returns a bit-array indicating which register 7391 sets are supported 7392 (bitfields defined in arch/x86/include/uapi/asm/kvm.h). 7393 7394As described above in the kvm_sync_regs struct info in section :ref:`kvm_run`, 7395KVM_CAP_SYNC_REGS "allow[s] userspace to access certain guest registers 7396without having to call SET/GET_*REGS". This reduces overhead by eliminating 7397repeated ioctl calls for setting and/or getting register values. This is 7398particularly important when userspace is making synchronous guest state 7399modifications, e.g. when emulating and/or intercepting instructions in 7400userspace. 7401 7402For s390 specifics, please refer to the source code. 7403 7404For x86: 7405 7406- the register sets to be copied out to kvm_run are selectable 7407 by userspace (rather that all sets being copied out for every exit). 7408- vcpu_events are available in addition to regs and sregs. 7409 7410For x86, the 'kvm_valid_regs' field of struct kvm_run is overloaded to 7411function as an input bit-array field set by userspace to indicate the 7412specific register sets to be copied out on the next exit. 7413 7414To indicate when userspace has modified values that should be copied into 7415the vCPU, the all architecture bitarray field, 'kvm_dirty_regs' must be set. 7416This is done using the same bitflags as for the 'kvm_valid_regs' field. 7417If the dirty bit is not set, then the register set values will not be copied 7418into the vCPU even if they've been modified. 7419 7420Unused bitfields in the bitarrays must be set to zero. 7421 7422:: 7423 7424 struct kvm_sync_regs { 7425 struct kvm_regs regs; 7426 struct kvm_sregs sregs; 7427 struct kvm_vcpu_events events; 7428 }; 7429 74306.75 KVM_CAP_PPC_IRQ_XIVE 7431------------------------- 7432 7433:Architectures: ppc 7434:Target: vcpu 7435:Parameters: args[0] is the XIVE device fd; 7436 args[1] is the XIVE CPU number (server ID) for this vcpu 7437 7438This capability connects the vcpu to an in-kernel XIVE device. 7439 7440.. _cap_enable_vm: 7441 74427. Capabilities that can be enabled on VMs 7443========================================== 7444 7445There are certain capabilities that change the behavior of the virtual 7446machine when enabled. To enable them, please see section 7447:ref:`KVM_ENABLE_CAP`. Below you can find a list of capabilities and 7448what their effect on the VM is when enabling them. 7449 7450The following information is provided along with the description: 7451 7452 Architectures: 7453 which instruction set architectures provide this ioctl. 7454 x86 includes both i386 and x86_64. 7455 7456 Parameters: 7457 what parameters are accepted by the capability. 7458 7459 Returns: 7460 the return value. General error numbers (EBADF, ENOMEM, EINVAL) 7461 are not detailed, but errors with specific meanings are. 7462 7463 74647.1 KVM_CAP_PPC_ENABLE_HCALL 7465---------------------------- 7466 7467:Architectures: ppc 7468:Parameters: args[0] is the sPAPR hcall number; 7469 args[1] is 0 to disable, 1 to enable in-kernel handling 7470 7471This capability controls whether individual sPAPR hypercalls (hcalls) 7472get handled by the kernel or not. Enabling or disabling in-kernel 7473handling of an hcall is effective across the VM. On creation, an 7474initial set of hcalls are enabled for in-kernel handling, which 7475consists of those hcalls for which in-kernel handlers were implemented 7476before this capability was implemented. If disabled, the kernel will 7477not to attempt to handle the hcall, but will always exit to userspace 7478to handle it. Note that it may not make sense to enable some and 7479disable others of a group of related hcalls, but KVM does not prevent 7480userspace from doing that. 7481 7482If the hcall number specified is not one that has an in-kernel 7483implementation, the KVM_ENABLE_CAP ioctl will fail with an EINVAL 7484error. 7485 74867.2 KVM_CAP_S390_USER_SIGP 7487-------------------------- 7488 7489:Architectures: s390 7490:Parameters: none 7491 7492This capability controls which SIGP orders will be handled completely in user 7493space. With this capability enabled, all fast orders will be handled completely 7494in the kernel: 7495 7496- SENSE 7497- SENSE RUNNING 7498- EXTERNAL CALL 7499- EMERGENCY SIGNAL 7500- CONDITIONAL EMERGENCY SIGNAL 7501 7502All other orders will be handled completely in user space. 7503 7504Only privileged operation exceptions will be checked for in the kernel (or even 7505in the hardware prior to interception). If this capability is not enabled, the 7506old way of handling SIGP orders is used (partially in kernel and user space). 7507 75087.3 KVM_CAP_S390_VECTOR_REGISTERS 7509--------------------------------- 7510 7511:Architectures: s390 7512:Parameters: none 7513:Returns: 0 on success, negative value on error 7514 7515Allows use of the vector registers introduced with z13 processor, and 7516provides for the synchronization between host and user space. Will 7517return -EINVAL if the machine does not support vectors. 7518 75197.4 KVM_CAP_S390_USER_STSI 7520-------------------------- 7521 7522:Architectures: s390 7523:Parameters: none 7524 7525This capability allows post-handlers for the STSI instruction. After 7526initial handling in the kernel, KVM exits to user space with 7527KVM_EXIT_S390_STSI to allow user space to insert further data. 7528 7529Before exiting to userspace, kvm handlers should fill in s390_stsi field of 7530vcpu->run:: 7531 7532 struct { 7533 __u64 addr; 7534 __u8 ar; 7535 __u8 reserved; 7536 __u8 fc; 7537 __u8 sel1; 7538 __u16 sel2; 7539 } s390_stsi; 7540 7541 @addr - guest address of STSI SYSIB 7542 @fc - function code 7543 @sel1 - selector 1 7544 @sel2 - selector 2 7545 @ar - access register number 7546 7547KVM handlers should exit to userspace with rc = -EREMOTE. 7548 75497.5 KVM_CAP_SPLIT_IRQCHIP 7550------------------------- 7551 7552:Architectures: x86 7553:Parameters: args[0] - number of routes reserved for userspace IOAPICs 7554:Returns: 0 on success, -1 on error 7555 7556Create a local apic for each processor in the kernel. This can be used 7557instead of KVM_CREATE_IRQCHIP if the userspace VMM wishes to emulate the 7558IOAPIC and PIC (and also the PIT, even though this has to be enabled 7559separately). 7560 7561This capability also enables in kernel routing of interrupt requests; 7562when KVM_CAP_SPLIT_IRQCHIP only routes of KVM_IRQ_ROUTING_MSI type are 7563used in the IRQ routing table. The first args[0] MSI routes are reserved 7564for the IOAPIC pins. Whenever the LAPIC receives an EOI for these routes, 7565a KVM_EXIT_IOAPIC_EOI vmexit will be reported to userspace. 7566 7567Fails if VCPU has already been created, or if the irqchip is already in the 7568kernel (i.e. KVM_CREATE_IRQCHIP has already been called). 7569 75707.6 KVM_CAP_S390_RI 7571------------------- 7572 7573:Architectures: s390 7574:Parameters: none 7575 7576Allows use of runtime-instrumentation introduced with zEC12 processor. 7577Will return -EINVAL if the machine does not support runtime-instrumentation. 7578Will return -EBUSY if a VCPU has already been created. 7579 75807.7 KVM_CAP_X2APIC_API 7581---------------------- 7582 7583:Architectures: x86 7584:Parameters: args[0] - features that should be enabled 7585:Returns: 0 on success, -EINVAL when args[0] contains invalid features 7586 7587Valid feature flags in args[0] are:: 7588 7589 #define KVM_X2APIC_API_USE_32BIT_IDS (1ULL << 0) 7590 #define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK (1ULL << 1) 7591 7592Enabling KVM_X2APIC_API_USE_32BIT_IDS changes the behavior of 7593KVM_SET_GSI_ROUTING, KVM_SIGNAL_MSI, KVM_SET_LAPIC, and KVM_GET_LAPIC, 7594allowing the use of 32-bit APIC IDs. See KVM_CAP_X2APIC_API in their 7595respective sections. 7596 7597KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK must be enabled for x2APIC to work 7598in logical mode or with more than 255 VCPUs. Otherwise, KVM treats 0xff 7599as a broadcast even in x2APIC mode in order to support physical x2APIC 7600without interrupt remapping. This is undesirable in logical mode, 7601where 0xff represents CPUs 0-7 in cluster 0. 7602 76037.8 KVM_CAP_S390_USER_INSTR0 7604---------------------------- 7605 7606:Architectures: s390 7607:Parameters: none 7608 7609With this capability enabled, all illegal instructions 0x0000 (2 bytes) will 7610be intercepted and forwarded to user space. User space can use this 7611mechanism e.g. to realize 2-byte software breakpoints. The kernel will 7612not inject an operating exception for these instructions, user space has 7613to take care of that. 7614 7615This capability can be enabled dynamically even if VCPUs were already 7616created and are running. 7617 76187.9 KVM_CAP_S390_GS 7619------------------- 7620 7621:Architectures: s390 7622:Parameters: none 7623:Returns: 0 on success; -EINVAL if the machine does not support 7624 guarded storage; -EBUSY if a VCPU has already been created. 7625 7626Allows use of guarded storage for the KVM guest. 7627 76287.10 KVM_CAP_S390_AIS 7629--------------------- 7630 7631:Architectures: s390 7632:Parameters: none 7633 7634Allow use of adapter-interruption suppression. 7635:Returns: 0 on success; -EBUSY if a VCPU has already been created. 7636 76377.11 KVM_CAP_PPC_SMT 7638-------------------- 7639 7640:Architectures: ppc 7641:Parameters: vsmt_mode, flags 7642 7643Enabling this capability on a VM provides userspace with a way to set 7644the desired virtual SMT mode (i.e. the number of virtual CPUs per 7645virtual core). The virtual SMT mode, vsmt_mode, must be a power of 2 7646between 1 and 8. On POWER8, vsmt_mode must also be no greater than 7647the number of threads per subcore for the host. Currently flags must 7648be 0. A successful call to enable this capability will result in 7649vsmt_mode being returned when the KVM_CAP_PPC_SMT capability is 7650subsequently queried for the VM. This capability is only supported by 7651HV KVM, and can only be set before any VCPUs have been created. 7652The KVM_CAP_PPC_SMT_POSSIBLE capability indicates which virtual SMT 7653modes are available. 7654 76557.12 KVM_CAP_PPC_FWNMI 7656---------------------- 7657 7658:Architectures: ppc 7659:Parameters: none 7660 7661With this capability a machine check exception in the guest address 7662space will cause KVM to exit the guest with NMI exit reason. This 7663enables QEMU to build error log and branch to guest kernel registered 7664machine check handling routine. Without this capability KVM will 7665branch to guests' 0x200 interrupt vector. 7666 76677.13 KVM_CAP_X86_DISABLE_EXITS 7668------------------------------ 7669 7670:Architectures: x86 7671:Parameters: args[0] defines which exits are disabled 7672:Returns: 0 on success, -EINVAL when args[0] contains invalid exits 7673 7674Valid bits in args[0] are:: 7675 7676 #define KVM_X86_DISABLE_EXITS_MWAIT (1 << 0) 7677 #define KVM_X86_DISABLE_EXITS_HLT (1 << 1) 7678 #define KVM_X86_DISABLE_EXITS_PAUSE (1 << 2) 7679 #define KVM_X86_DISABLE_EXITS_CSTATE (1 << 3) 7680 7681Enabling this capability on a VM provides userspace with a way to no 7682longer intercept some instructions for improved latency in some 7683workloads, and is suggested when vCPUs are associated to dedicated 7684physical CPUs. More bits can be added in the future; userspace can 7685just pass the KVM_CHECK_EXTENSION result to KVM_ENABLE_CAP to disable 7686all such vmexits. 7687 7688Do not enable KVM_FEATURE_PV_UNHALT if you disable HLT exits. 7689 76907.14 KVM_CAP_S390_HPAGE_1M 7691-------------------------- 7692 7693:Architectures: s390 7694:Parameters: none 7695:Returns: 0 on success, -EINVAL if hpage module parameter was not set 7696 or cmma is enabled, or the VM has the KVM_VM_S390_UCONTROL 7697 flag set 7698 7699With this capability the KVM support for memory backing with 1m pages 7700through hugetlbfs can be enabled for a VM. After the capability is 7701enabled, cmma can't be enabled anymore and pfmfi and the storage key 7702interpretation are disabled. If cmma has already been enabled or the 7703hpage module parameter is not set to 1, -EINVAL is returned. 7704 7705While it is generally possible to create a huge page backed VM without 7706this capability, the VM will not be able to run. 7707 77087.15 KVM_CAP_MSR_PLATFORM_INFO 7709------------------------------ 7710 7711:Architectures: x86 7712:Parameters: args[0] whether feature should be enabled or not 7713 7714With this capability, a guest may read the MSR_PLATFORM_INFO MSR. Otherwise, 7715a #GP would be raised when the guest tries to access. Currently, this 7716capability does not enable write permissions of this MSR for the guest. 7717 77187.16 KVM_CAP_PPC_NESTED_HV 7719-------------------------- 7720 7721:Architectures: ppc 7722:Parameters: none 7723:Returns: 0 on success, -EINVAL when the implementation doesn't support 7724 nested-HV virtualization. 7725 7726HV-KVM on POWER9 and later systems allows for "nested-HV" 7727virtualization, which provides a way for a guest VM to run guests that 7728can run using the CPU's supervisor mode (privileged non-hypervisor 7729state). Enabling this capability on a VM depends on the CPU having 7730the necessary functionality and on the facility being enabled with a 7731kvm-hv module parameter. 7732 77337.17 KVM_CAP_EXCEPTION_PAYLOAD 7734------------------------------ 7735 7736:Architectures: x86 7737:Parameters: args[0] whether feature should be enabled or not 7738 7739With this capability enabled, CR2 will not be modified prior to the 7740emulated VM-exit when L1 intercepts a #PF exception that occurs in 7741L2. Similarly, for kvm-intel only, DR6 will not be modified prior to 7742the emulated VM-exit when L1 intercepts a #DB exception that occurs in 7743L2. As a result, when KVM_GET_VCPU_EVENTS reports a pending #PF (or 7744#DB) exception for L2, exception.has_payload will be set and the 7745faulting address (or the new DR6 bits*) will be reported in the 7746exception_payload field. Similarly, when userspace injects a #PF (or 7747#DB) into L2 using KVM_SET_VCPU_EVENTS, it is expected to set 7748exception.has_payload and to put the faulting address - or the new DR6 7749bits\ [#]_ - in the exception_payload field. 7750 7751This capability also enables exception.pending in struct 7752kvm_vcpu_events, which allows userspace to distinguish between pending 7753and injected exceptions. 7754 7755 7756.. [#] For the new DR6 bits, note that bit 16 is set iff the #DB exception 7757 will clear DR6.RTM. 7758 77597.18 KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 7760-------------------------------------- 7761 7762:Architectures: x86, arm64, mips 7763:Parameters: args[0] whether feature should be enabled or not 7764 7765Valid flags are:: 7766 7767 #define KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE (1 << 0) 7768 #define KVM_DIRTY_LOG_INITIALLY_SET (1 << 1) 7769 7770With KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE is set, KVM_GET_DIRTY_LOG will not 7771automatically clear and write-protect all pages that are returned as dirty. 7772Rather, userspace will have to do this operation separately using 7773KVM_CLEAR_DIRTY_LOG. 7774 7775At the cost of a slightly more complicated operation, this provides better 7776scalability and responsiveness for two reasons. First, 7777KVM_CLEAR_DIRTY_LOG ioctl can operate on a 64-page granularity rather 7778than requiring to sync a full memslot; this ensures that KVM does not 7779take spinlocks for an extended period of time. Second, in some cases a 7780large amount of time can pass between a call to KVM_GET_DIRTY_LOG and 7781userspace actually using the data in the page. Pages can be modified 7782during this time, which is inefficient for both the guest and userspace: 7783the guest will incur a higher penalty due to write protection faults, 7784while userspace can see false reports of dirty pages. Manual reprotection 7785helps reducing this time, improving guest performance and reducing the 7786number of dirty log false positives. 7787 7788With KVM_DIRTY_LOG_INITIALLY_SET set, all the bits of the dirty bitmap 7789will be initialized to 1 when created. This also improves performance because 7790dirty logging can be enabled gradually in small chunks on the first call 7791to KVM_CLEAR_DIRTY_LOG. KVM_DIRTY_LOG_INITIALLY_SET depends on 7792KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE (it is also only available on 7793x86 and arm64 for now). 7794 7795KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 was previously available under the name 7796KVM_CAP_MANUAL_DIRTY_LOG_PROTECT, but the implementation had bugs that make 7797it hard or impossible to use it correctly. The availability of 7798KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 signals that those bugs are fixed. 7799Userspace should not try to use KVM_CAP_MANUAL_DIRTY_LOG_PROTECT. 7800 78017.19 KVM_CAP_PPC_SECURE_GUEST 7802------------------------------ 7803 7804:Architectures: ppc 7805 7806This capability indicates that KVM is running on a host that has 7807ultravisor firmware and thus can support a secure guest. On such a 7808system, a guest can ask the ultravisor to make it a secure guest, 7809one whose memory is inaccessible to the host except for pages which 7810are explicitly requested to be shared with the host. The ultravisor 7811notifies KVM when a guest requests to become a secure guest, and KVM 7812has the opportunity to veto the transition. 7813 7814If present, this capability can be enabled for a VM, meaning that KVM 7815will allow the transition to secure guest mode. Otherwise KVM will 7816veto the transition. 7817 78187.20 KVM_CAP_HALT_POLL 7819---------------------- 7820 7821:Architectures: all 7822:Target: VM 7823:Parameters: args[0] is the maximum poll time in nanoseconds 7824:Returns: 0 on success; -1 on error 7825 7826KVM_CAP_HALT_POLL overrides the kvm.halt_poll_ns module parameter to set the 7827maximum halt-polling time for all vCPUs in the target VM. This capability can 7828be invoked at any time and any number of times to dynamically change the 7829maximum halt-polling time. 7830 7831See Documentation/virt/kvm/halt-polling.rst for more information on halt 7832polling. 7833 78347.21 KVM_CAP_X86_USER_SPACE_MSR 7835------------------------------- 7836 7837:Architectures: x86 7838:Target: VM 7839:Parameters: args[0] contains the mask of KVM_MSR_EXIT_REASON_* events to report 7840:Returns: 0 on success; -1 on error 7841 7842This capability allows userspace to intercept RDMSR and WRMSR instructions if 7843access to an MSR is denied. By default, KVM injects #GP on denied accesses. 7844 7845When a guest requests to read or write an MSR, KVM may not implement all MSRs 7846that are relevant to a respective system. It also does not differentiate by 7847CPU type. 7848 7849To allow more fine grained control over MSR handling, userspace may enable 7850this capability. With it enabled, MSR accesses that match the mask specified in 7851args[0] and would trigger a #GP inside the guest will instead trigger 7852KVM_EXIT_X86_RDMSR and KVM_EXIT_X86_WRMSR exit notifications. Userspace 7853can then implement model specific MSR handling and/or user notifications 7854to inform a user that an MSR was not emulated/virtualized by KVM. 7855 7856The valid mask flags are: 7857 7858============================ =============================================== 7859 KVM_MSR_EXIT_REASON_UNKNOWN intercept accesses to unknown (to KVM) MSRs 7860 KVM_MSR_EXIT_REASON_INVAL intercept accesses that are architecturally 7861 invalid according to the vCPU model and/or mode 7862 KVM_MSR_EXIT_REASON_FILTER intercept accesses that are denied by userspace 7863 via KVM_X86_SET_MSR_FILTER 7864============================ =============================================== 7865 78667.22 KVM_CAP_X86_BUS_LOCK_EXIT 7867------------------------------- 7868 7869:Architectures: x86 7870:Target: VM 7871:Parameters: args[0] defines the policy used when bus locks detected in guest 7872:Returns: 0 on success, -EINVAL when args[0] contains invalid bits 7873 7874Valid bits in args[0] are:: 7875 7876 #define KVM_BUS_LOCK_DETECTION_OFF (1 << 0) 7877 #define KVM_BUS_LOCK_DETECTION_EXIT (1 << 1) 7878 7879Enabling this capability on a VM provides userspace with a way to select a 7880policy to handle the bus locks detected in guest. Userspace can obtain the 7881supported modes from the result of KVM_CHECK_EXTENSION and define it through 7882the KVM_ENABLE_CAP. The supported modes are mutually-exclusive. 7883 7884This capability allows userspace to force VM exits on bus locks detected in the 7885guest, irrespective whether or not the host has enabled split-lock detection 7886(which triggers an #AC exception that KVM intercepts). This capability is 7887intended to mitigate attacks where a malicious/buggy guest can exploit bus 7888locks to degrade the performance of the whole system. 7889 7890If KVM_BUS_LOCK_DETECTION_OFF is set, KVM doesn't force guest bus locks to VM 7891exit, although the host kernel's split-lock #AC detection still applies, if 7892enabled. 7893 7894If KVM_BUS_LOCK_DETECTION_EXIT is set, KVM enables a CPU feature that ensures 7895bus locks in the guest trigger a VM exit, and KVM exits to userspace for all 7896such VM exits, e.g. to allow userspace to throttle the offending guest and/or 7897apply some other policy-based mitigation. When exiting to userspace, KVM sets 7898KVM_RUN_X86_BUS_LOCK in vcpu-run->flags, and conditionally sets the exit_reason 7899to KVM_EXIT_X86_BUS_LOCK. 7900 7901Note! Detected bus locks may be coincident with other exits to userspace, i.e. 7902KVM_RUN_X86_BUS_LOCK should be checked regardless of the primary exit reason if 7903userspace wants to take action on all detected bus locks. 7904 79057.23 KVM_CAP_PPC_DAWR1 7906---------------------- 7907 7908:Architectures: ppc 7909:Parameters: none 7910:Returns: 0 on success, -EINVAL when CPU doesn't support 2nd DAWR 7911 7912This capability can be used to check / enable 2nd DAWR feature provided 7913by POWER10 processor. 7914 7915 79167.24 KVM_CAP_VM_COPY_ENC_CONTEXT_FROM 7917------------------------------------- 7918 7919Architectures: x86 SEV enabled 7920Type: vm 7921Parameters: args[0] is the fd of the source vm 7922Returns: 0 on success; ENOTTY on error 7923 7924This capability enables userspace to copy encryption context from the vm 7925indicated by the fd to the vm this is called on. 7926 7927This is intended to support in-guest workloads scheduled by the host. This 7928allows the in-guest workload to maintain its own NPTs and keeps the two vms 7929from accidentally clobbering each other with interrupts and the like (separate 7930APIC/MSRs/etc). 7931 79327.25 KVM_CAP_SGX_ATTRIBUTE 7933-------------------------- 7934 7935:Architectures: x86 7936:Target: VM 7937:Parameters: args[0] is a file handle of a SGX attribute file in securityfs 7938:Returns: 0 on success, -EINVAL if the file handle is invalid or if a requested 7939 attribute is not supported by KVM. 7940 7941KVM_CAP_SGX_ATTRIBUTE enables a userspace VMM to grant a VM access to one or 7942more privileged enclave attributes. args[0] must hold a file handle to a valid 7943SGX attribute file corresponding to an attribute that is supported/restricted 7944by KVM (currently only PROVISIONKEY). 7945 7946The SGX subsystem restricts access to a subset of enclave attributes to provide 7947additional security for an uncompromised kernel, e.g. use of the PROVISIONKEY 7948is restricted to deter malware from using the PROVISIONKEY to obtain a stable 7949system fingerprint. To prevent userspace from circumventing such restrictions 7950by running an enclave in a VM, KVM prevents access to privileged attributes by 7951default. 7952 7953See Documentation/arch/x86/sgx.rst for more details. 7954 79557.26 KVM_CAP_PPC_RPT_INVALIDATE 7956------------------------------- 7957 7958:Capability: KVM_CAP_PPC_RPT_INVALIDATE 7959:Architectures: ppc 7960:Type: vm 7961 7962This capability indicates that the kernel is capable of handling 7963H_RPT_INVALIDATE hcall. 7964 7965In order to enable the use of H_RPT_INVALIDATE in the guest, 7966user space might have to advertise it for the guest. For example, 7967IBM pSeries (sPAPR) guest starts using it if "hcall-rpt-invalidate" is 7968present in the "ibm,hypertas-functions" device-tree property. 7969 7970This capability is enabled for hypervisors on platforms like POWER9 7971that support radix MMU. 7972 79737.27 KVM_CAP_EXIT_ON_EMULATION_FAILURE 7974-------------------------------------- 7975 7976:Architectures: x86 7977:Parameters: args[0] whether the feature should be enabled or not 7978 7979When this capability is enabled, an emulation failure will result in an exit 7980to userspace with KVM_INTERNAL_ERROR (except when the emulator was invoked 7981to handle a VMware backdoor instruction). Furthermore, KVM will now provide up 7982to 15 instruction bytes for any exit to userspace resulting from an emulation 7983failure. When these exits to userspace occur use the emulation_failure struct 7984instead of the internal struct. They both have the same layout, but the 7985emulation_failure struct matches the content better. It also explicitly 7986defines the 'flags' field which is used to describe the fields in the struct 7987that are valid (ie: if KVM_INTERNAL_ERROR_EMULATION_FLAG_INSTRUCTION_BYTES is 7988set in the 'flags' field then both 'insn_size' and 'insn_bytes' have valid data 7989in them.) 7990 79917.28 KVM_CAP_ARM_MTE 7992-------------------- 7993 7994:Architectures: arm64 7995:Parameters: none 7996 7997This capability indicates that KVM (and the hardware) supports exposing the 7998Memory Tagging Extensions (MTE) to the guest. It must also be enabled by the 7999VMM before creating any VCPUs to allow the guest access. Note that MTE is only 8000available to a guest running in AArch64 mode and enabling this capability will 8001cause attempts to create AArch32 VCPUs to fail. 8002 8003When enabled the guest is able to access tags associated with any memory given 8004to the guest. KVM will ensure that the tags are maintained during swap or 8005hibernation of the host; however the VMM needs to manually save/restore the 8006tags as appropriate if the VM is migrated. 8007 8008When this capability is enabled all memory in memslots must be mapped as 8009``MAP_ANONYMOUS`` or with a RAM-based file mapping (``tmpfs``, ``memfd``), 8010attempts to create a memslot with an invalid mmap will result in an 8011-EINVAL return. 8012 8013When enabled the VMM may make use of the ``KVM_ARM_MTE_COPY_TAGS`` ioctl to 8014perform a bulk copy of tags to/from the guest. 8015 80167.29 KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM 8017------------------------------------- 8018 8019:Architectures: x86 SEV enabled 8020:Type: vm 8021:Parameters: args[0] is the fd of the source vm 8022:Returns: 0 on success 8023 8024This capability enables userspace to migrate the encryption context from the VM 8025indicated by the fd to the VM this is called on. 8026 8027This is intended to support intra-host migration of VMs between userspace VMMs, 8028upgrading the VMM process without interrupting the guest. 8029 80307.30 KVM_CAP_PPC_AIL_MODE_3 8031------------------------------- 8032 8033:Capability: KVM_CAP_PPC_AIL_MODE_3 8034:Architectures: ppc 8035:Type: vm 8036 8037This capability indicates that the kernel supports the mode 3 setting for the 8038"Address Translation Mode on Interrupt" aka "Alternate Interrupt Location" 8039resource that is controlled with the H_SET_MODE hypercall. 8040 8041This capability allows a guest kernel to use a better-performance mode for 8042handling interrupts and system calls. 8043 80447.31 KVM_CAP_DISABLE_QUIRKS2 8045---------------------------- 8046 8047:Capability: KVM_CAP_DISABLE_QUIRKS2 8048:Parameters: args[0] - set of KVM quirks to disable 8049:Architectures: x86 8050:Type: vm 8051 8052This capability, if enabled, will cause KVM to disable some behavior 8053quirks. 8054 8055Calling KVM_CHECK_EXTENSION for this capability returns a bitmask of 8056quirks that can be disabled in KVM. 8057 8058The argument to KVM_ENABLE_CAP for this capability is a bitmask of 8059quirks to disable, and must be a subset of the bitmask returned by 8060KVM_CHECK_EXTENSION. 8061 8062The valid bits in cap.args[0] are: 8063 8064=================================== ============================================ 8065 KVM_X86_QUIRK_LINT0_REENABLED By default, the reset value for the LVT 8066 LINT0 register is 0x700 (APIC_MODE_EXTINT). 8067 When this quirk is disabled, the reset value 8068 is 0x10000 (APIC_LVT_MASKED). 8069 8070 KVM_X86_QUIRK_CD_NW_CLEARED By default, KVM clears CR0.CD and CR0.NW on 8071 AMD CPUs to workaround buggy guest firmware 8072 that runs in perpetuity with CR0.CD, i.e. 8073 with caches in "no fill" mode. 8074 8075 When this quirk is disabled, KVM does not 8076 change the value of CR0.CD and CR0.NW. 8077 8078 KVM_X86_QUIRK_LAPIC_MMIO_HOLE By default, the MMIO LAPIC interface is 8079 available even when configured for x2APIC 8080 mode. When this quirk is disabled, KVM 8081 disables the MMIO LAPIC interface if the 8082 LAPIC is in x2APIC mode. 8083 8084 KVM_X86_QUIRK_OUT_7E_INC_RIP By default, KVM pre-increments %rip before 8085 exiting to userspace for an OUT instruction 8086 to port 0x7e. When this quirk is disabled, 8087 KVM does not pre-increment %rip before 8088 exiting to userspace. 8089 8090 KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT When this quirk is disabled, KVM sets 8091 CPUID.01H:ECX[bit 3] (MONITOR/MWAIT) if 8092 IA32_MISC_ENABLE[bit 18] (MWAIT) is set. 8093 Additionally, when this quirk is disabled, 8094 KVM clears CPUID.01H:ECX[bit 3] if 8095 IA32_MISC_ENABLE[bit 18] is cleared. 8096 8097 KVM_X86_QUIRK_FIX_HYPERCALL_INSN By default, KVM rewrites guest 8098 VMMCALL/VMCALL instructions to match the 8099 vendor's hypercall instruction for the 8100 system. When this quirk is disabled, KVM 8101 will no longer rewrite invalid guest 8102 hypercall instructions. Executing the 8103 incorrect hypercall instruction will 8104 generate a #UD within the guest. 8105 8106KVM_X86_QUIRK_MWAIT_NEVER_UD_FAULTS By default, KVM emulates MONITOR/MWAIT (if 8107 they are intercepted) as NOPs regardless of 8108 whether or not MONITOR/MWAIT are supported 8109 according to guest CPUID. When this quirk 8110 is disabled and KVM_X86_DISABLE_EXITS_MWAIT 8111 is not set (MONITOR/MWAIT are intercepted), 8112 KVM will inject a #UD on MONITOR/MWAIT if 8113 they're unsupported per guest CPUID. Note, 8114 KVM will modify MONITOR/MWAIT support in 8115 guest CPUID on writes to MISC_ENABLE if 8116 KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT is 8117 disabled. 8118 8119KVM_X86_QUIRK_SLOT_ZAP_ALL By default, for KVM_X86_DEFAULT_VM VMs, KVM 8120 invalidates all SPTEs in all memslots and 8121 address spaces when a memslot is deleted or 8122 moved. When this quirk is disabled (or the 8123 VM type isn't KVM_X86_DEFAULT_VM), KVM only 8124 ensures the backing memory of the deleted 8125 or moved memslot isn't reachable, i.e KVM 8126 _may_ invalidate only SPTEs related to the 8127 memslot. 8128 8129KVM_X86_QUIRK_STUFF_FEATURE_MSRS By default, at vCPU creation, KVM sets the 8130 vCPU's MSR_IA32_PERF_CAPABILITIES (0x345), 8131 MSR_IA32_ARCH_CAPABILITIES (0x10a), 8132 MSR_PLATFORM_INFO (0xce), and all VMX MSRs 8133 (0x480..0x492) to the maximal capabilities 8134 supported by KVM. KVM also sets 8135 MSR_IA32_UCODE_REV (0x8b) to an arbitrary 8136 value (which is different for Intel vs. 8137 AMD). Lastly, when guest CPUID is set (by 8138 userspace), KVM modifies select VMX MSR 8139 fields to force consistency between guest 8140 CPUID and L2's effective ISA. When this 8141 quirk is disabled, KVM zeroes the vCPU's MSR 8142 values (with two exceptions, see below), 8143 i.e. treats the feature MSRs like CPUID 8144 leaves and gives userspace full control of 8145 the vCPU model definition. This quirk does 8146 not affect VMX MSRs CR0/CR4_FIXED1 (0x487 8147 and 0x489), as KVM does now allow them to 8148 be set by userspace (KVM sets them based on 8149 guest CPUID, for safety purposes). 8150=================================== ============================================ 8151 81527.32 KVM_CAP_MAX_VCPU_ID 8153------------------------ 8154 8155:Architectures: x86 8156:Target: VM 8157:Parameters: args[0] - maximum APIC ID value set for current VM 8158:Returns: 0 on success, -EINVAL if args[0] is beyond KVM_MAX_VCPU_IDS 8159 supported in KVM or if it has been set. 8160 8161This capability allows userspace to specify maximum possible APIC ID 8162assigned for current VM session prior to the creation of vCPUs, saving 8163memory for data structures indexed by the APIC ID. Userspace is able 8164to calculate the limit to APIC ID values from designated 8165CPU topology. 8166 8167The value can be changed only until KVM_ENABLE_CAP is set to a nonzero 8168value or until a vCPU is created. Upon creation of the first vCPU, 8169if the value was set to zero or KVM_ENABLE_CAP was not invoked, KVM 8170uses the return value of KVM_CHECK_EXTENSION(KVM_CAP_MAX_VCPU_ID) as 8171the maximum APIC ID. 8172 81737.33 KVM_CAP_X86_NOTIFY_VMEXIT 8174------------------------------ 8175 8176:Architectures: x86 8177:Target: VM 8178:Parameters: args[0] is the value of notify window as well as some flags 8179:Returns: 0 on success, -EINVAL if args[0] contains invalid flags or notify 8180 VM exit is unsupported. 8181 8182Bits 63:32 of args[0] are used for notify window. 8183Bits 31:0 of args[0] are for some flags. Valid bits are:: 8184 8185 #define KVM_X86_NOTIFY_VMEXIT_ENABLED (1 << 0) 8186 #define KVM_X86_NOTIFY_VMEXIT_USER (1 << 1) 8187 8188This capability allows userspace to configure the notify VM exit on/off 8189in per-VM scope during VM creation. Notify VM exit is disabled by default. 8190When userspace sets KVM_X86_NOTIFY_VMEXIT_ENABLED bit in args[0], VMM will 8191enable this feature with the notify window provided, which will generate 8192a VM exit if no event window occurs in VM non-root mode for a specified of 8193time (notify window). 8194 8195If KVM_X86_NOTIFY_VMEXIT_USER is set in args[0], upon notify VM exits happen, 8196KVM would exit to userspace for handling. 8197 8198This capability is aimed to mitigate the threat that malicious VMs can 8199cause CPU stuck (due to event windows don't open up) and make the CPU 8200unavailable to host or other VMs. 8201 82027.34 KVM_CAP_MEMORY_FAULT_INFO 8203------------------------------ 8204 8205:Architectures: x86 8206:Returns: Informational only, -EINVAL on direct KVM_ENABLE_CAP. 8207 8208The presence of this capability indicates that KVM_RUN will fill 8209kvm_run.memory_fault if KVM cannot resolve a guest page fault VM-Exit, e.g. if 8210there is a valid memslot but no backing VMA for the corresponding host virtual 8211address. 8212 8213The information in kvm_run.memory_fault is valid if and only if KVM_RUN returns 8214an error with errno=EFAULT or errno=EHWPOISON *and* kvm_run.exit_reason is set 8215to KVM_EXIT_MEMORY_FAULT. 8216 8217Note: Userspaces which attempt to resolve memory faults so that they can retry 8218KVM_RUN are encouraged to guard against repeatedly receiving the same 8219error/annotated fault. 8220 8221See KVM_EXIT_MEMORY_FAULT for more information. 8222 82237.35 KVM_CAP_X86_APIC_BUS_CYCLES_NS 8224----------------------------------- 8225 8226:Architectures: x86 8227:Target: VM 8228:Parameters: args[0] is the desired APIC bus clock rate, in nanoseconds 8229:Returns: 0 on success, -EINVAL if args[0] contains an invalid value for the 8230 frequency or if any vCPUs have been created, -ENXIO if a virtual 8231 local APIC has not been created using KVM_CREATE_IRQCHIP. 8232 8233This capability sets the VM's APIC bus clock frequency, used by KVM's in-kernel 8234virtual APIC when emulating APIC timers. KVM's default value can be retrieved 8235by KVM_CHECK_EXTENSION. 8236 8237Note: Userspace is responsible for correctly configuring CPUID 0x15, a.k.a. the 8238core crystal clock frequency, if a non-zero CPUID 0x15 is exposed to the guest. 8239 82407.36 KVM_CAP_X86_GUEST_MODE 8241------------------------------ 8242 8243:Architectures: x86 8244:Returns: Informational only, -EINVAL on direct KVM_ENABLE_CAP. 8245 8246The presence of this capability indicates that KVM_RUN will update the 8247KVM_RUN_X86_GUEST_MODE bit in kvm_run.flags to indicate whether the 8248vCPU was executing nested guest code when it exited. 8249 8250KVM exits with the register state of either the L1 or L2 guest 8251depending on which executed at the time of an exit. Userspace must 8252take care to differentiate between these cases. 8253 82548. Other capabilities. 8255====================== 8256 8257This section lists capabilities that give information about other 8258features of the KVM implementation. 8259 82608.1 KVM_CAP_PPC_HWRNG 8261--------------------- 8262 8263:Architectures: ppc 8264 8265This capability, if KVM_CHECK_EXTENSION indicates that it is 8266available, means that the kernel has an implementation of the 8267H_RANDOM hypercall backed by a hardware random-number generator. 8268If present, the kernel H_RANDOM handler can be enabled for guest use 8269with the KVM_CAP_PPC_ENABLE_HCALL capability. 8270 82718.2 KVM_CAP_HYPERV_SYNIC 8272------------------------ 8273 8274:Architectures: x86 8275 8276This capability, if KVM_CHECK_EXTENSION indicates that it is 8277available, means that the kernel has an implementation of the 8278Hyper-V Synthetic interrupt controller(SynIC). Hyper-V SynIC is 8279used to support Windows Hyper-V based guest paravirt drivers(VMBus). 8280 8281In order to use SynIC, it has to be activated by setting this 8282capability via KVM_ENABLE_CAP ioctl on the vcpu fd. Note that this 8283will disable the use of APIC hardware virtualization even if supported 8284by the CPU, as it's incompatible with SynIC auto-EOI behavior. 8285 82868.3 KVM_CAP_PPC_MMU_RADIX 8287------------------------- 8288 8289:Architectures: ppc 8290 8291This capability, if KVM_CHECK_EXTENSION indicates that it is 8292available, means that the kernel can support guests using the 8293radix MMU defined in Power ISA V3.00 (as implemented in the POWER9 8294processor). 8295 82968.4 KVM_CAP_PPC_MMU_HASH_V3 8297--------------------------- 8298 8299:Architectures: ppc 8300 8301This capability, if KVM_CHECK_EXTENSION indicates that it is 8302available, means that the kernel can support guests using the 8303hashed page table MMU defined in Power ISA V3.00 (as implemented in 8304the POWER9 processor), including in-memory segment tables. 8305 83068.5 KVM_CAP_MIPS_VZ 8307------------------- 8308 8309:Architectures: mips 8310 8311This capability, if KVM_CHECK_EXTENSION on the main kvm handle indicates that 8312it is available, means that full hardware assisted virtualization capabilities 8313of the hardware are available for use through KVM. An appropriate 8314KVM_VM_MIPS_* type must be passed to KVM_CREATE_VM to create a VM which 8315utilises it. 8316 8317If KVM_CHECK_EXTENSION on a kvm VM handle indicates that this capability is 8318available, it means that the VM is using full hardware assisted virtualization 8319capabilities of the hardware. This is useful to check after creating a VM with 8320KVM_VM_MIPS_DEFAULT. 8321 8322The value returned by KVM_CHECK_EXTENSION should be compared against known 8323values (see below). All other values are reserved. This is to allow for the 8324possibility of other hardware assisted virtualization implementations which 8325may be incompatible with the MIPS VZ ASE. 8326 8327== ========================================================================== 8328 0 The trap & emulate implementation is in use to run guest code in user 8329 mode. Guest virtual memory segments are rearranged to fit the guest in the 8330 user mode address space. 8331 8332 1 The MIPS VZ ASE is in use, providing full hardware assisted 8333 virtualization, including standard guest virtual memory segments. 8334== ========================================================================== 8335 83368.6 KVM_CAP_MIPS_TE 8337------------------- 8338 8339:Architectures: mips 8340 8341This capability, if KVM_CHECK_EXTENSION on the main kvm handle indicates that 8342it is available, means that the trap & emulate implementation is available to 8343run guest code in user mode, even if KVM_CAP_MIPS_VZ indicates that hardware 8344assisted virtualisation is also available. KVM_VM_MIPS_TE (0) must be passed 8345to KVM_CREATE_VM to create a VM which utilises it. 8346 8347If KVM_CHECK_EXTENSION on a kvm VM handle indicates that this capability is 8348available, it means that the VM is using trap & emulate. 8349 83508.7 KVM_CAP_MIPS_64BIT 8351---------------------- 8352 8353:Architectures: mips 8354 8355This capability indicates the supported architecture type of the guest, i.e. the 8356supported register and address width. 8357 8358The values returned when this capability is checked by KVM_CHECK_EXTENSION on a 8359kvm VM handle correspond roughly to the CP0_Config.AT register field, and should 8360be checked specifically against known values (see below). All other values are 8361reserved. 8362 8363== ======================================================================== 8364 0 MIPS32 or microMIPS32. 8365 Both registers and addresses are 32-bits wide. 8366 It will only be possible to run 32-bit guest code. 8367 8368 1 MIPS64 or microMIPS64 with access only to 32-bit compatibility segments. 8369 Registers are 64-bits wide, but addresses are 32-bits wide. 8370 64-bit guest code may run but cannot access MIPS64 memory segments. 8371 It will also be possible to run 32-bit guest code. 8372 8373 2 MIPS64 or microMIPS64 with access to all address segments. 8374 Both registers and addresses are 64-bits wide. 8375 It will be possible to run 64-bit or 32-bit guest code. 8376== ======================================================================== 8377 83788.9 KVM_CAP_ARM_USER_IRQ 8379------------------------ 8380 8381:Architectures: arm64 8382 8383This capability, if KVM_CHECK_EXTENSION indicates that it is available, means 8384that if userspace creates a VM without an in-kernel interrupt controller, it 8385will be notified of changes to the output level of in-kernel emulated devices, 8386which can generate virtual interrupts, presented to the VM. 8387For such VMs, on every return to userspace, the kernel 8388updates the vcpu's run->s.regs.device_irq_level field to represent the actual 8389output level of the device. 8390 8391Whenever kvm detects a change in the device output level, kvm guarantees at 8392least one return to userspace before running the VM. This exit could either 8393be a KVM_EXIT_INTR or any other exit event, like KVM_EXIT_MMIO. This way, 8394userspace can always sample the device output level and re-compute the state of 8395the userspace interrupt controller. Userspace should always check the state 8396of run->s.regs.device_irq_level on every kvm exit. 8397The value in run->s.regs.device_irq_level can represent both level and edge 8398triggered interrupt signals, depending on the device. Edge triggered interrupt 8399signals will exit to userspace with the bit in run->s.regs.device_irq_level 8400set exactly once per edge signal. 8401 8402The field run->s.regs.device_irq_level is available independent of 8403run->kvm_valid_regs or run->kvm_dirty_regs bits. 8404 8405If KVM_CAP_ARM_USER_IRQ is supported, the KVM_CHECK_EXTENSION ioctl returns a 8406number larger than 0 indicating the version of this capability is implemented 8407and thereby which bits in run->s.regs.device_irq_level can signal values. 8408 8409Currently the following bits are defined for the device_irq_level bitmap:: 8410 8411 KVM_CAP_ARM_USER_IRQ >= 1: 8412 8413 KVM_ARM_DEV_EL1_VTIMER - EL1 virtual timer 8414 KVM_ARM_DEV_EL1_PTIMER - EL1 physical timer 8415 KVM_ARM_DEV_PMU - ARM PMU overflow interrupt signal 8416 8417Future versions of kvm may implement additional events. These will get 8418indicated by returning a higher number from KVM_CHECK_EXTENSION and will be 8419listed above. 8420 84218.10 KVM_CAP_PPC_SMT_POSSIBLE 8422----------------------------- 8423 8424:Architectures: ppc 8425 8426Querying this capability returns a bitmap indicating the possible 8427virtual SMT modes that can be set using KVM_CAP_PPC_SMT. If bit N 8428(counting from the right) is set, then a virtual SMT mode of 2^N is 8429available. 8430 84318.11 KVM_CAP_HYPERV_SYNIC2 8432-------------------------- 8433 8434:Architectures: x86 8435 8436This capability enables a newer version of Hyper-V Synthetic interrupt 8437controller (SynIC). The only difference with KVM_CAP_HYPERV_SYNIC is that KVM 8438doesn't clear SynIC message and event flags pages when they are enabled by 8439writing to the respective MSRs. 8440 84418.12 KVM_CAP_HYPERV_VP_INDEX 8442---------------------------- 8443 8444:Architectures: x86 8445 8446This capability indicates that userspace can load HV_X64_MSR_VP_INDEX msr. Its 8447value is used to denote the target vcpu for a SynIC interrupt. For 8448compatibility, KVM initializes this msr to KVM's internal vcpu index. When this 8449capability is absent, userspace can still query this msr's value. 8450 84518.13 KVM_CAP_S390_AIS_MIGRATION 8452------------------------------- 8453 8454:Architectures: s390 8455:Parameters: none 8456 8457This capability indicates if the flic device will be able to get/set the 8458AIS states for migration via the KVM_DEV_FLIC_AISM_ALL attribute and allows 8459to discover this without having to create a flic device. 8460 84618.14 KVM_CAP_S390_PSW 8462--------------------- 8463 8464:Architectures: s390 8465 8466This capability indicates that the PSW is exposed via the kvm_run structure. 8467 84688.15 KVM_CAP_S390_GMAP 8469---------------------- 8470 8471:Architectures: s390 8472 8473This capability indicates that the user space memory used as guest mapping can 8474be anywhere in the user memory address space, as long as the memory slots are 8475aligned and sized to a segment (1MB) boundary. 8476 84778.16 KVM_CAP_S390_COW 8478--------------------- 8479 8480:Architectures: s390 8481 8482This capability indicates that the user space memory used as guest mapping can 8483use copy-on-write semantics as well as dirty pages tracking via read-only page 8484tables. 8485 84868.17 KVM_CAP_S390_BPB 8487--------------------- 8488 8489:Architectures: s390 8490 8491This capability indicates that kvm will implement the interfaces to handle 8492reset, migration and nested KVM for branch prediction blocking. The stfle 8493facility 82 should not be provided to the guest without this capability. 8494 84958.18 KVM_CAP_HYPERV_TLBFLUSH 8496---------------------------- 8497 8498:Architectures: x86 8499 8500This capability indicates that KVM supports paravirtualized Hyper-V TLB Flush 8501hypercalls: 8502HvFlushVirtualAddressSpace, HvFlushVirtualAddressSpaceEx, 8503HvFlushVirtualAddressList, HvFlushVirtualAddressListEx. 8504 85058.19 KVM_CAP_ARM_INJECT_SERROR_ESR 8506---------------------------------- 8507 8508:Architectures: arm64 8509 8510This capability indicates that userspace can specify (via the 8511KVM_SET_VCPU_EVENTS ioctl) the syndrome value reported to the guest when it 8512takes a virtual SError interrupt exception. 8513If KVM advertises this capability, userspace can only specify the ISS field for 8514the ESR syndrome. Other parts of the ESR, such as the EC are generated by the 8515CPU when the exception is taken. If this virtual SError is taken to EL1 using 8516AArch64, this value will be reported in the ISS field of ESR_ELx. 8517 8518See KVM_CAP_VCPU_EVENTS for more details. 8519 85208.20 KVM_CAP_HYPERV_SEND_IPI 8521---------------------------- 8522 8523:Architectures: x86 8524 8525This capability indicates that KVM supports paravirtualized Hyper-V IPI send 8526hypercalls: 8527HvCallSendSyntheticClusterIpi, HvCallSendSyntheticClusterIpiEx. 8528 85298.21 KVM_CAP_HYPERV_DIRECT_TLBFLUSH 8530----------------------------------- 8531 8532:Architectures: x86 8533 8534This capability indicates that KVM running on top of Hyper-V hypervisor 8535enables Direct TLB flush for its guests meaning that TLB flush 8536hypercalls are handled by Level 0 hypervisor (Hyper-V) bypassing KVM. 8537Due to the different ABI for hypercall parameters between Hyper-V and 8538KVM, enabling this capability effectively disables all hypercall 8539handling by KVM (as some KVM hypercall may be mistakenly treated as TLB 8540flush hypercalls by Hyper-V) so userspace should disable KVM identification 8541in CPUID and only exposes Hyper-V identification. In this case, guest 8542thinks it's running on Hyper-V and only use Hyper-V hypercalls. 8543 85448.22 KVM_CAP_S390_VCPU_RESETS 8545----------------------------- 8546 8547:Architectures: s390 8548 8549This capability indicates that the KVM_S390_NORMAL_RESET and 8550KVM_S390_CLEAR_RESET ioctls are available. 8551 85528.23 KVM_CAP_S390_PROTECTED 8553--------------------------- 8554 8555:Architectures: s390 8556 8557This capability indicates that the Ultravisor has been initialized and 8558KVM can therefore start protected VMs. 8559This capability governs the KVM_S390_PV_COMMAND ioctl and the 8560KVM_MP_STATE_LOAD MP_STATE. KVM_SET_MP_STATE can fail for protected 8561guests when the state change is invalid. 8562 85638.24 KVM_CAP_STEAL_TIME 8564----------------------- 8565 8566:Architectures: arm64, x86 8567 8568This capability indicates that KVM supports steal time accounting. 8569When steal time accounting is supported it may be enabled with 8570architecture-specific interfaces. This capability and the architecture- 8571specific interfaces must be consistent, i.e. if one says the feature 8572is supported, than the other should as well and vice versa. For arm64 8573see Documentation/virt/kvm/devices/vcpu.rst "KVM_ARM_VCPU_PVTIME_CTRL". 8574For x86 see Documentation/virt/kvm/x86/msr.rst "MSR_KVM_STEAL_TIME". 8575 85768.25 KVM_CAP_S390_DIAG318 8577------------------------- 8578 8579:Architectures: s390 8580 8581This capability enables a guest to set information about its control program 8582(i.e. guest kernel type and version). The information is helpful during 8583system/firmware service events, providing additional data about the guest 8584environments running on the machine. 8585 8586The information is associated with the DIAGNOSE 0x318 instruction, which sets 8587an 8-byte value consisting of a one-byte Control Program Name Code (CPNC) and 8588a 7-byte Control Program Version Code (CPVC). The CPNC determines what 8589environment the control program is running in (e.g. Linux, z/VM...), and the 8590CPVC is used for information specific to OS (e.g. Linux version, Linux 8591distribution...) 8592 8593If this capability is available, then the CPNC and CPVC can be synchronized 8594between KVM and userspace via the sync regs mechanism (KVM_SYNC_DIAG318). 8595 85968.26 KVM_CAP_X86_USER_SPACE_MSR 8597------------------------------- 8598 8599:Architectures: x86 8600 8601This capability indicates that KVM supports deflection of MSR reads and 8602writes to user space. It can be enabled on a VM level. If enabled, MSR 8603accesses that would usually trigger a #GP by KVM into the guest will 8604instead get bounced to user space through the KVM_EXIT_X86_RDMSR and 8605KVM_EXIT_X86_WRMSR exit notifications. 8606 86078.27 KVM_CAP_X86_MSR_FILTER 8608--------------------------- 8609 8610:Architectures: x86 8611 8612This capability indicates that KVM supports that accesses to user defined MSRs 8613may be rejected. With this capability exposed, KVM exports new VM ioctl 8614KVM_X86_SET_MSR_FILTER which user space can call to specify bitmaps of MSR 8615ranges that KVM should deny access to. 8616 8617In combination with KVM_CAP_X86_USER_SPACE_MSR, this allows user space to 8618trap and emulate MSRs that are outside of the scope of KVM as well as 8619limit the attack surface on KVM's MSR emulation code. 8620 86218.28 KVM_CAP_ENFORCE_PV_FEATURE_CPUID 8622------------------------------------- 8623 8624Architectures: x86 8625 8626When enabled, KVM will disable paravirtual features provided to the 8627guest according to the bits in the KVM_CPUID_FEATURES CPUID leaf 8628(0x40000001). Otherwise, a guest may use the paravirtual features 8629regardless of what has actually been exposed through the CPUID leaf. 8630 8631.. _KVM_CAP_DIRTY_LOG_RING: 8632 86338.29 KVM_CAP_DIRTY_LOG_RING/KVM_CAP_DIRTY_LOG_RING_ACQ_REL 8634---------------------------------------------------------- 8635 8636:Architectures: x86, arm64 8637:Parameters: args[0] - size of the dirty log ring 8638 8639KVM is capable of tracking dirty memory using ring buffers that are 8640mmapped into userspace; there is one dirty ring per vcpu. 8641 8642The dirty ring is available to userspace as an array of 8643``struct kvm_dirty_gfn``. Each dirty entry is defined as:: 8644 8645 struct kvm_dirty_gfn { 8646 __u32 flags; 8647 __u32 slot; /* as_id | slot_id */ 8648 __u64 offset; 8649 }; 8650 8651The following values are defined for the flags field to define the 8652current state of the entry:: 8653 8654 #define KVM_DIRTY_GFN_F_DIRTY BIT(0) 8655 #define KVM_DIRTY_GFN_F_RESET BIT(1) 8656 #define KVM_DIRTY_GFN_F_MASK 0x3 8657 8658Userspace should call KVM_ENABLE_CAP ioctl right after KVM_CREATE_VM 8659ioctl to enable this capability for the new guest and set the size of 8660the rings. Enabling the capability is only allowed before creating any 8661vCPU, and the size of the ring must be a power of two. The larger the 8662ring buffer, the less likely the ring is full and the VM is forced to 8663exit to userspace. The optimal size depends on the workload, but it is 8664recommended that it be at least 64 KiB (4096 entries). 8665 8666Just like for dirty page bitmaps, the buffer tracks writes to 8667all user memory regions for which the KVM_MEM_LOG_DIRTY_PAGES flag was 8668set in KVM_SET_USER_MEMORY_REGION. Once a memory region is registered 8669with the flag set, userspace can start harvesting dirty pages from the 8670ring buffer. 8671 8672An entry in the ring buffer can be unused (flag bits ``00``), 8673dirty (flag bits ``01``) or harvested (flag bits ``1X``). The 8674state machine for the entry is as follows:: 8675 8676 dirtied harvested reset 8677 00 -----------> 01 -------------> 1X -------+ 8678 ^ | 8679 | | 8680 +------------------------------------------+ 8681 8682To harvest the dirty pages, userspace accesses the mmapped ring buffer 8683to read the dirty GFNs. If the flags has the DIRTY bit set (at this stage 8684the RESET bit must be cleared), then it means this GFN is a dirty GFN. 8685The userspace should harvest this GFN and mark the flags from state 8686``01b`` to ``1Xb`` (bit 0 will be ignored by KVM, but bit 1 must be set 8687to show that this GFN is harvested and waiting for a reset), and move 8688on to the next GFN. The userspace should continue to do this until the 8689flags of a GFN have the DIRTY bit cleared, meaning that it has harvested 8690all the dirty GFNs that were available. 8691 8692Note that on weakly ordered architectures, userspace accesses to the 8693ring buffer (and more specifically the 'flags' field) must be ordered, 8694using load-acquire/store-release accessors when available, or any 8695other memory barrier that will ensure this ordering. 8696 8697It's not necessary for userspace to harvest the all dirty GFNs at once. 8698However it must collect the dirty GFNs in sequence, i.e., the userspace 8699program cannot skip one dirty GFN to collect the one next to it. 8700 8701After processing one or more entries in the ring buffer, userspace 8702calls the VM ioctl KVM_RESET_DIRTY_RINGS to notify the kernel about 8703it, so that the kernel will reprotect those collected GFNs. 8704Therefore, the ioctl must be called *before* reading the content of 8705the dirty pages. 8706 8707The dirty ring can get full. When it happens, the KVM_RUN of the 8708vcpu will return with exit reason KVM_EXIT_DIRTY_LOG_FULL. 8709 8710The dirty ring interface has a major difference comparing to the 8711KVM_GET_DIRTY_LOG interface in that, when reading the dirty ring from 8712userspace, it's still possible that the kernel has not yet flushed the 8713processor's dirty page buffers into the kernel buffer (with dirty bitmaps, the 8714flushing is done by the KVM_GET_DIRTY_LOG ioctl). To achieve that, one 8715needs to kick the vcpu out of KVM_RUN using a signal. The resulting 8716vmexit ensures that all dirty GFNs are flushed to the dirty rings. 8717 8718NOTE: KVM_CAP_DIRTY_LOG_RING_ACQ_REL is the only capability that 8719should be exposed by weakly ordered architecture, in order to indicate 8720the additional memory ordering requirements imposed on userspace when 8721reading the state of an entry and mutating it from DIRTY to HARVESTED. 8722Architecture with TSO-like ordering (such as x86) are allowed to 8723expose both KVM_CAP_DIRTY_LOG_RING and KVM_CAP_DIRTY_LOG_RING_ACQ_REL 8724to userspace. 8725 8726After enabling the dirty rings, the userspace needs to detect the 8727capability of KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP to see whether the 8728ring structures can be backed by per-slot bitmaps. With this capability 8729advertised, it means the architecture can dirty guest pages without 8730vcpu/ring context, so that some of the dirty information will still be 8731maintained in the bitmap structure. KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP 8732can't be enabled if the capability of KVM_CAP_DIRTY_LOG_RING_ACQ_REL 8733hasn't been enabled, or any memslot has been existing. 8734 8735Note that the bitmap here is only a backup of the ring structure. The 8736use of the ring and bitmap combination is only beneficial if there is 8737only a very small amount of memory that is dirtied out of vcpu/ring 8738context. Otherwise, the stand-alone per-slot bitmap mechanism needs to 8739be considered. 8740 8741To collect dirty bits in the backup bitmap, userspace can use the same 8742KVM_GET_DIRTY_LOG ioctl. KVM_CLEAR_DIRTY_LOG isn't needed as long as all 8743the generation of the dirty bits is done in a single pass. Collecting 8744the dirty bitmap should be the very last thing that the VMM does before 8745considering the state as complete. VMM needs to ensure that the dirty 8746state is final and avoid missing dirty pages from another ioctl ordered 8747after the bitmap collection. 8748 8749NOTE: Multiple examples of using the backup bitmap: (1) save vgic/its 8750tables through command KVM_DEV_ARM_{VGIC_GRP_CTRL, ITS_SAVE_TABLES} on 8751KVM device "kvm-arm-vgic-its". (2) restore vgic/its tables through 8752command KVM_DEV_ARM_{VGIC_GRP_CTRL, ITS_RESTORE_TABLES} on KVM device 8753"kvm-arm-vgic-its". VGICv3 LPI pending status is restored. (3) save 8754vgic3 pending table through KVM_DEV_ARM_VGIC_{GRP_CTRL, SAVE_PENDING_TABLES} 8755command on KVM device "kvm-arm-vgic-v3". 8756 87578.30 KVM_CAP_XEN_HVM 8758-------------------- 8759 8760:Architectures: x86 8761 8762This capability indicates the features that Xen supports for hosting Xen 8763PVHVM guests. Valid flags are:: 8764 8765 #define KVM_XEN_HVM_CONFIG_HYPERCALL_MSR (1 << 0) 8766 #define KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL (1 << 1) 8767 #define KVM_XEN_HVM_CONFIG_SHARED_INFO (1 << 2) 8768 #define KVM_XEN_HVM_CONFIG_RUNSTATE (1 << 3) 8769 #define KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL (1 << 4) 8770 #define KVM_XEN_HVM_CONFIG_EVTCHN_SEND (1 << 5) 8771 #define KVM_XEN_HVM_CONFIG_RUNSTATE_UPDATE_FLAG (1 << 6) 8772 #define KVM_XEN_HVM_CONFIG_PVCLOCK_TSC_UNSTABLE (1 << 7) 8773 8774The KVM_XEN_HVM_CONFIG_HYPERCALL_MSR flag indicates that the KVM_XEN_HVM_CONFIG 8775ioctl is available, for the guest to set its hypercall page. 8776 8777If KVM_XEN_HVM_CONFIG_INTERCEPT_HCALL is also set, the same flag may also be 8778provided in the flags to KVM_XEN_HVM_CONFIG, without providing hypercall page 8779contents, to request that KVM generate hypercall page content automatically 8780and also enable interception of guest hypercalls with KVM_EXIT_XEN. 8781 8782The KVM_XEN_HVM_CONFIG_SHARED_INFO flag indicates the availability of the 8783KVM_XEN_HVM_SET_ATTR, KVM_XEN_HVM_GET_ATTR, KVM_XEN_VCPU_SET_ATTR and 8784KVM_XEN_VCPU_GET_ATTR ioctls, as well as the delivery of exception vectors 8785for event channel upcalls when the evtchn_upcall_pending field of a vcpu's 8786vcpu_info is set. 8787 8788The KVM_XEN_HVM_CONFIG_RUNSTATE flag indicates that the runstate-related 8789features KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADDR/_CURRENT/_DATA/_ADJUST are 8790supported by the KVM_XEN_VCPU_SET_ATTR/KVM_XEN_VCPU_GET_ATTR ioctls. 8791 8792The KVM_XEN_HVM_CONFIG_EVTCHN_2LEVEL flag indicates that IRQ routing entries 8793of the type KVM_IRQ_ROUTING_XEN_EVTCHN are supported, with the priority 8794field set to indicate 2 level event channel delivery. 8795 8796The KVM_XEN_HVM_CONFIG_EVTCHN_SEND flag indicates that KVM supports 8797injecting event channel events directly into the guest with the 8798KVM_XEN_HVM_EVTCHN_SEND ioctl. It also indicates support for the 8799KVM_XEN_ATTR_TYPE_EVTCHN/XEN_VERSION HVM attributes and the 8800KVM_XEN_VCPU_ATTR_TYPE_VCPU_ID/TIMER/UPCALL_VECTOR vCPU attributes. 8801related to event channel delivery, timers, and the XENVER_version 8802interception. 8803 8804The KVM_XEN_HVM_CONFIG_RUNSTATE_UPDATE_FLAG flag indicates that KVM supports 8805the KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG attribute in the KVM_XEN_SET_ATTR 8806and KVM_XEN_GET_ATTR ioctls. This controls whether KVM will set the 8807XEN_RUNSTATE_UPDATE flag in guest memory mapped vcpu_runstate_info during 8808updates of the runstate information. Note that versions of KVM which support 8809the RUNSTATE feature above, but not the RUNSTATE_UPDATE_FLAG feature, will 8810always set the XEN_RUNSTATE_UPDATE flag when updating the guest structure, 8811which is perhaps counterintuitive. When this flag is advertised, KVM will 8812behave more correctly, not using the XEN_RUNSTATE_UPDATE flag until/unless 8813specifically enabled (by the guest making the hypercall, causing the VMM 8814to enable the KVM_XEN_ATTR_TYPE_RUNSTATE_UPDATE_FLAG attribute). 8815 8816The KVM_XEN_HVM_CONFIG_PVCLOCK_TSC_UNSTABLE flag indicates that KVM supports 8817clearing the PVCLOCK_TSC_STABLE_BIT flag in Xen pvclock sources. This will be 8818done when the KVM_CAP_XEN_HVM ioctl sets the 8819KVM_XEN_HVM_CONFIG_PVCLOCK_TSC_UNSTABLE flag. 8820 88218.31 KVM_CAP_PPC_MULTITCE 8822------------------------- 8823 8824:Capability: KVM_CAP_PPC_MULTITCE 8825:Architectures: ppc 8826:Type: vm 8827 8828This capability means the kernel is capable of handling hypercalls 8829H_PUT_TCE_INDIRECT and H_STUFF_TCE without passing those into the user 8830space. This significantly accelerates DMA operations for PPC KVM guests. 8831User space should expect that its handlers for these hypercalls 8832are not going to be called if user space previously registered LIOBN 8833in KVM (via KVM_CREATE_SPAPR_TCE or similar calls). 8834 8835In order to enable H_PUT_TCE_INDIRECT and H_STUFF_TCE use in the guest, 8836user space might have to advertise it for the guest. For example, 8837IBM pSeries (sPAPR) guest starts using them if "hcall-multi-tce" is 8838present in the "ibm,hypertas-functions" device-tree property. 8839 8840The hypercalls mentioned above may or may not be processed successfully 8841in the kernel based fast path. If they can not be handled by the kernel, 8842they will get passed on to user space. So user space still has to have 8843an implementation for these despite the in kernel acceleration. 8844 8845This capability is always enabled. 8846 88478.32 KVM_CAP_PTP_KVM 8848-------------------- 8849 8850:Architectures: arm64 8851 8852This capability indicates that the KVM virtual PTP service is 8853supported in the host. A VMM can check whether the service is 8854available to the guest on migration. 8855 88568.33 KVM_CAP_HYPERV_ENFORCE_CPUID 8857--------------------------------- 8858 8859Architectures: x86 8860 8861When enabled, KVM will disable emulated Hyper-V features provided to the 8862guest according to the bits Hyper-V CPUID feature leaves. Otherwise, all 8863currently implemented Hyper-V features are provided unconditionally when 8864Hyper-V identification is set in the HYPERV_CPUID_INTERFACE (0x40000001) 8865leaf. 8866 88678.34 KVM_CAP_EXIT_HYPERCALL 8868--------------------------- 8869 8870:Capability: KVM_CAP_EXIT_HYPERCALL 8871:Architectures: x86 8872:Type: vm 8873 8874This capability, if enabled, will cause KVM to exit to userspace 8875with KVM_EXIT_HYPERCALL exit reason to process some hypercalls. 8876 8877Calling KVM_CHECK_EXTENSION for this capability will return a bitmask 8878of hypercalls that can be configured to exit to userspace. 8879Right now, the only such hypercall is KVM_HC_MAP_GPA_RANGE. 8880 8881The argument to KVM_ENABLE_CAP is also a bitmask, and must be a subset 8882of the result of KVM_CHECK_EXTENSION. KVM will forward to userspace 8883the hypercalls whose corresponding bit is in the argument, and return 8884ENOSYS for the others. 8885 88868.35 KVM_CAP_PMU_CAPABILITY 8887--------------------------- 8888 8889:Capability: KVM_CAP_PMU_CAPABILITY 8890:Architectures: x86 8891:Type: vm 8892:Parameters: arg[0] is bitmask of PMU virtualization capabilities. 8893:Returns: 0 on success, -EINVAL when arg[0] contains invalid bits 8894 8895This capability alters PMU virtualization in KVM. 8896 8897Calling KVM_CHECK_EXTENSION for this capability returns a bitmask of 8898PMU virtualization capabilities that can be adjusted on a VM. 8899 8900The argument to KVM_ENABLE_CAP is also a bitmask and selects specific 8901PMU virtualization capabilities to be applied to the VM. This can 8902only be invoked on a VM prior to the creation of VCPUs. 8903 8904At this time, KVM_PMU_CAP_DISABLE is the only capability. Setting 8905this capability will disable PMU virtualization for that VM. Usermode 8906should adjust CPUID leaf 0xA to reflect that the PMU is disabled. 8907 89088.36 KVM_CAP_ARM_SYSTEM_SUSPEND 8909------------------------------- 8910 8911:Capability: KVM_CAP_ARM_SYSTEM_SUSPEND 8912:Architectures: arm64 8913:Type: vm 8914 8915When enabled, KVM will exit to userspace with KVM_EXIT_SYSTEM_EVENT of 8916type KVM_SYSTEM_EVENT_SUSPEND to process the guest suspend request. 8917 89188.37 KVM_CAP_S390_PROTECTED_DUMP 8919-------------------------------- 8920 8921:Capability: KVM_CAP_S390_PROTECTED_DUMP 8922:Architectures: s390 8923:Type: vm 8924 8925This capability indicates that KVM and the Ultravisor support dumping 8926PV guests. The `KVM_PV_DUMP` command is available for the 8927`KVM_S390_PV_COMMAND` ioctl and the `KVM_PV_INFO` command provides 8928dump related UV data. Also the vcpu ioctl `KVM_S390_PV_CPU_COMMAND` is 8929available and supports the `KVM_PV_DUMP_CPU` subcommand. 8930 89318.38 KVM_CAP_VM_DISABLE_NX_HUGE_PAGES 8932------------------------------------- 8933 8934:Capability: KVM_CAP_VM_DISABLE_NX_HUGE_PAGES 8935:Architectures: x86 8936:Type: vm 8937:Parameters: arg[0] must be 0. 8938:Returns: 0 on success, -EPERM if the userspace process does not 8939 have CAP_SYS_BOOT, -EINVAL if args[0] is not 0 or any vCPUs have been 8940 created. 8941 8942This capability disables the NX huge pages mitigation for iTLB MULTIHIT. 8943 8944The capability has no effect if the nx_huge_pages module parameter is not set. 8945 8946This capability may only be set before any vCPUs are created. 8947 89488.39 KVM_CAP_S390_CPU_TOPOLOGY 8949------------------------------ 8950 8951:Capability: KVM_CAP_S390_CPU_TOPOLOGY 8952:Architectures: s390 8953:Type: vm 8954 8955This capability indicates that KVM will provide the S390 CPU Topology 8956facility which consist of the interpretation of the PTF instruction for 8957the function code 2 along with interception and forwarding of both the 8958PTF instruction with function codes 0 or 1 and the STSI(15,1,x) 8959instruction to the userland hypervisor. 8960 8961The stfle facility 11, CPU Topology facility, should not be indicated 8962to the guest without this capability. 8963 8964When this capability is present, KVM provides a new attribute group 8965on vm fd, KVM_S390_VM_CPU_TOPOLOGY. 8966This new attribute allows to get, set or clear the Modified Change 8967Topology Report (MTCR) bit of the SCA through the kvm_device_attr 8968structure. 8969 8970When getting the Modified Change Topology Report value, the attr->addr 8971must point to a byte where the value will be stored or retrieved from. 8972 89738.40 KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE 8974--------------------------------------- 8975 8976:Capability: KVM_CAP_ARM_EAGER_SPLIT_CHUNK_SIZE 8977:Architectures: arm64 8978:Type: vm 8979:Parameters: arg[0] is the new split chunk size. 8980:Returns: 0 on success, -EINVAL if any memslot was already created. 8981 8982This capability sets the chunk size used in Eager Page Splitting. 8983 8984Eager Page Splitting improves the performance of dirty-logging (used 8985in live migrations) when guest memory is backed by huge-pages. It 8986avoids splitting huge-pages (into PAGE_SIZE pages) on fault, by doing 8987it eagerly when enabling dirty logging (with the 8988KVM_MEM_LOG_DIRTY_PAGES flag for a memory region), or when using 8989KVM_CLEAR_DIRTY_LOG. 8990 8991The chunk size specifies how many pages to break at a time, using a 8992single allocation for each chunk. Bigger the chunk size, more pages 8993need to be allocated ahead of time. 8994 8995The chunk size needs to be a valid block size. The list of acceptable 8996block sizes is exposed in KVM_CAP_ARM_SUPPORTED_BLOCK_SIZES as a 899764-bit bitmap (each bit describing a block size). The default value is 89980, to disable the eager page splitting. 8999 90008.41 KVM_CAP_VM_TYPES 9001--------------------- 9002 9003:Capability: KVM_CAP_MEMORY_ATTRIBUTES 9004:Architectures: x86 9005:Type: system ioctl 9006 9007This capability returns a bitmap of support VM types. The 1-setting of bit @n 9008means the VM type with value @n is supported. Possible values of @n are:: 9009 9010 #define KVM_X86_DEFAULT_VM 0 9011 #define KVM_X86_SW_PROTECTED_VM 1 9012 #define KVM_X86_SEV_VM 2 9013 #define KVM_X86_SEV_ES_VM 3 9014 9015Note, KVM_X86_SW_PROTECTED_VM is currently only for development and testing. 9016Do not use KVM_X86_SW_PROTECTED_VM for "real" VMs, and especially not in 9017production. The behavior and effective ABI for software-protected VMs is 9018unstable. 9019 90209. Known KVM API problems 9021========================= 9022 9023In some cases, KVM's API has some inconsistencies or common pitfalls 9024that userspace need to be aware of. This section details some of 9025these issues. 9026 9027Most of them are architecture specific, so the section is split by 9028architecture. 9029 90309.1. x86 9031-------- 9032 9033``KVM_GET_SUPPORTED_CPUID`` issues 9034^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 9035 9036In general, ``KVM_GET_SUPPORTED_CPUID`` is designed so that it is possible 9037to take its result and pass it directly to ``KVM_SET_CPUID2``. This section 9038documents some cases in which that requires some care. 9039 9040Local APIC features 9041~~~~~~~~~~~~~~~~~~~ 9042 9043CPU[EAX=1]:ECX[21] (X2APIC) is reported by ``KVM_GET_SUPPORTED_CPUID``, 9044but it can only be enabled if ``KVM_CREATE_IRQCHIP`` or 9045``KVM_ENABLE_CAP(KVM_CAP_IRQCHIP_SPLIT)`` are used to enable in-kernel emulation of 9046the local APIC. 9047 9048The same is true for the ``KVM_FEATURE_PV_UNHALT`` paravirtualized feature. 9049 9050CPU[EAX=1]:ECX[24] (TSC_DEADLINE) is not reported by ``KVM_GET_SUPPORTED_CPUID``. 9051It can be enabled if ``KVM_CAP_TSC_DEADLINE_TIMER`` is present and the kernel 9052has enabled in-kernel emulation of the local APIC. 9053 9054CPU topology 9055~~~~~~~~~~~~ 9056 9057Several CPUID values include topology information for the host CPU: 90580x0b and 0x1f for Intel systems, 0x8000001e for AMD systems. Different 9059versions of KVM return different values for this information and userspace 9060should not rely on it. Currently they return all zeroes. 9061 9062If userspace wishes to set up a guest topology, it should be careful that 9063the values of these three leaves differ for each CPU. In particular, 9064the APIC ID is found in EDX for all subleaves of 0x0b and 0x1f, and in EAX 9065for 0x8000001e; the latter also encodes the core id and node id in bits 90667:0 of EBX and ECX respectively. 9067 9068Obsolete ioctls and capabilities 9069^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 9070 9071KVM_CAP_DISABLE_QUIRKS does not let userspace know which quirks are actually 9072available. Use ``KVM_CHECK_EXTENSION(KVM_CAP_DISABLE_QUIRKS2)`` instead if 9073available. 9074 9075Ordering of KVM_GET_*/KVM_SET_* ioctls 9076^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 9077 9078TBD 9079