1 /* 2 * Core of Xen paravirt_ops implementation. 3 * 4 * This file contains the xen_paravirt_ops structure itself, and the 5 * implementations for: 6 * - privileged instructions 7 * - interrupt flags 8 * - segment operations 9 * - booting and setup 10 * 11 * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 12 */ 13 14 #include <linux/cpu.h> 15 #include <linux/kernel.h> 16 #include <linux/init.h> 17 #include <linux/smp.h> 18 #include <linux/preempt.h> 19 #include <linux/hardirq.h> 20 #include <linux/percpu.h> 21 #include <linux/delay.h> 22 #include <linux/start_kernel.h> 23 #include <linux/sched.h> 24 #include <linux/kprobes.h> 25 #include <linux/bootmem.h> 26 #include <linux/module.h> 27 #include <linux/mm.h> 28 #include <linux/page-flags.h> 29 #include <linux/highmem.h> 30 #include <linux/console.h> 31 #include <linux/pci.h> 32 #include <linux/gfp.h> 33 #include <linux/memblock.h> 34 #include <linux/edd.h> 35 #include <linux/frame.h> 36 37 #ifdef CONFIG_KEXEC_CORE 38 #include <linux/kexec.h> 39 #endif 40 41 #include <xen/xen.h> 42 #include <xen/events.h> 43 #include <xen/interface/xen.h> 44 #include <xen/interface/version.h> 45 #include <xen/interface/physdev.h> 46 #include <xen/interface/vcpu.h> 47 #include <xen/interface/memory.h> 48 #include <xen/interface/nmi.h> 49 #include <xen/interface/xen-mca.h> 50 #include <xen/features.h> 51 #include <xen/page.h> 52 #include <xen/hvm.h> 53 #include <xen/hvc-console.h> 54 #include <xen/acpi.h> 55 56 #include <asm/paravirt.h> 57 #include <asm/apic.h> 58 #include <asm/page.h> 59 #include <asm/xen/pci.h> 60 #include <asm/xen/hypercall.h> 61 #include <asm/xen/hypervisor.h> 62 #include <asm/fixmap.h> 63 #include <asm/processor.h> 64 #include <asm/proto.h> 65 #include <asm/msr-index.h> 66 #include <asm/traps.h> 67 #include <asm/setup.h> 68 #include <asm/desc.h> 69 #include <asm/pgalloc.h> 70 #include <asm/pgtable.h> 71 #include <asm/tlbflush.h> 72 #include <asm/reboot.h> 73 #include <asm/stackprotector.h> 74 #include <asm/hypervisor.h> 75 #include <asm/mach_traps.h> 76 #include <asm/mwait.h> 77 #include <asm/pci_x86.h> 78 #include <asm/cpu.h> 79 80 #ifdef CONFIG_ACPI 81 #include <linux/acpi.h> 82 #include <asm/acpi.h> 83 #include <acpi/pdc_intel.h> 84 #include <acpi/processor.h> 85 #include <xen/interface/platform.h> 86 #endif 87 88 #include "xen-ops.h" 89 #include "mmu.h" 90 #include "smp.h" 91 #include "multicalls.h" 92 #include "pmu.h" 93 94 EXPORT_SYMBOL_GPL(hypercall_page); 95 96 /* 97 * Pointer to the xen_vcpu_info structure or 98 * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info 99 * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info 100 * but if the hypervisor supports VCPUOP_register_vcpu_info then it can point 101 * to xen_vcpu_info. The pointer is used in __xen_evtchn_do_upcall to 102 * acknowledge pending events. 103 * Also more subtly it is used by the patched version of irq enable/disable 104 * e.g. xen_irq_enable_direct and xen_iret in PV mode. 105 * 106 * The desire to be able to do those mask/unmask operations as a single 107 * instruction by using the per-cpu offset held in %gs is the real reason 108 * vcpu info is in a per-cpu pointer and the original reason for this 109 * hypercall. 110 * 111 */ 112 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); 113 114 /* 115 * Per CPU pages used if hypervisor supports VCPUOP_register_vcpu_info 116 * hypercall. This can be used both in PV and PVHVM mode. The structure 117 * overrides the default per_cpu(xen_vcpu, cpu) value. 118 */ 119 DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info); 120 121 enum xen_domain_type xen_domain_type = XEN_NATIVE; 122 EXPORT_SYMBOL_GPL(xen_domain_type); 123 124 unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START; 125 EXPORT_SYMBOL(machine_to_phys_mapping); 126 unsigned long machine_to_phys_nr; 127 EXPORT_SYMBOL(machine_to_phys_nr); 128 129 struct start_info *xen_start_info; 130 EXPORT_SYMBOL_GPL(xen_start_info); 131 132 struct shared_info xen_dummy_shared_info; 133 134 void *xen_initial_gdt; 135 136 RESERVE_BRK(shared_info_page_brk, PAGE_SIZE); 137 __read_mostly int xen_have_vector_callback; 138 EXPORT_SYMBOL_GPL(xen_have_vector_callback); 139 140 /* 141 * Point at some empty memory to start with. We map the real shared_info 142 * page as soon as fixmap is up and running. 143 */ 144 struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info; 145 146 /* 147 * Flag to determine whether vcpu info placement is available on all 148 * VCPUs. We assume it is to start with, and then set it to zero on 149 * the first failure. This is because it can succeed on some VCPUs 150 * and not others, since it can involve hypervisor memory allocation, 151 * or because the guest failed to guarantee all the appropriate 152 * constraints on all VCPUs (ie buffer can't cross a page boundary). 153 * 154 * Note that any particular CPU may be using a placed vcpu structure, 155 * but we can only optimise if the all are. 156 * 157 * 0: not available, 1: available 158 */ 159 static int have_vcpu_info_placement = 1; 160 161 struct tls_descs { 162 struct desc_struct desc[3]; 163 }; 164 165 /* 166 * Updating the 3 TLS descriptors in the GDT on every task switch is 167 * surprisingly expensive so we avoid updating them if they haven't 168 * changed. Since Xen writes different descriptors than the one 169 * passed in the update_descriptor hypercall we keep shadow copies to 170 * compare against. 171 */ 172 static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc); 173 174 static void clamp_max_cpus(void) 175 { 176 #ifdef CONFIG_SMP 177 if (setup_max_cpus > MAX_VIRT_CPUS) 178 setup_max_cpus = MAX_VIRT_CPUS; 179 #endif 180 } 181 182 static void xen_vcpu_setup(int cpu) 183 { 184 struct vcpu_register_vcpu_info info; 185 int err; 186 struct vcpu_info *vcpup; 187 188 BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); 189 190 /* 191 * This path is called twice on PVHVM - first during bootup via 192 * smp_init -> xen_hvm_cpu_notify, and then if the VCPU is being 193 * hotplugged: cpu_up -> xen_hvm_cpu_notify. 194 * As we can only do the VCPUOP_register_vcpu_info once lets 195 * not over-write its result. 196 * 197 * For PV it is called during restore (xen_vcpu_restore) and bootup 198 * (xen_setup_vcpu_info_placement). The hotplug mechanism does not 199 * use this function. 200 */ 201 if (xen_hvm_domain()) { 202 if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu)) 203 return; 204 } 205 if (cpu < MAX_VIRT_CPUS) 206 per_cpu(xen_vcpu,cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu]; 207 208 if (!have_vcpu_info_placement) { 209 if (cpu >= MAX_VIRT_CPUS) 210 clamp_max_cpus(); 211 return; 212 } 213 214 vcpup = &per_cpu(xen_vcpu_info, cpu); 215 info.mfn = arbitrary_virt_to_mfn(vcpup); 216 info.offset = offset_in_page(vcpup); 217 218 /* Check to see if the hypervisor will put the vcpu_info 219 structure where we want it, which allows direct access via 220 a percpu-variable. 221 N.B. This hypercall can _only_ be called once per CPU. Subsequent 222 calls will error out with -EINVAL. This is due to the fact that 223 hypervisor has no unregister variant and this hypercall does not 224 allow to over-write info.mfn and info.offset. 225 */ 226 err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info); 227 228 if (err) { 229 printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err); 230 have_vcpu_info_placement = 0; 231 clamp_max_cpus(); 232 } else { 233 /* This cpu is using the registered vcpu info, even if 234 later ones fail to. */ 235 per_cpu(xen_vcpu, cpu) = vcpup; 236 } 237 } 238 239 /* 240 * On restore, set the vcpu placement up again. 241 * If it fails, then we're in a bad state, since 242 * we can't back out from using it... 243 */ 244 void xen_vcpu_restore(void) 245 { 246 int cpu; 247 248 for_each_possible_cpu(cpu) { 249 bool other_cpu = (cpu != smp_processor_id()); 250 bool is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up, cpu, NULL); 251 252 if (other_cpu && is_up && 253 HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL)) 254 BUG(); 255 256 xen_setup_runstate_info(cpu); 257 258 if (have_vcpu_info_placement) 259 xen_vcpu_setup(cpu); 260 261 if (other_cpu && is_up && 262 HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL)) 263 BUG(); 264 } 265 } 266 267 static void __init xen_banner(void) 268 { 269 unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL); 270 struct xen_extraversion extra; 271 HYPERVISOR_xen_version(XENVER_extraversion, &extra); 272 273 pr_info("Booting paravirtualized kernel %son %s\n", 274 xen_feature(XENFEAT_auto_translated_physmap) ? 275 "with PVH extensions " : "", pv_info.name); 276 printk(KERN_INFO "Xen version: %d.%d%s%s\n", 277 version >> 16, version & 0xffff, extra.extraversion, 278 xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : ""); 279 } 280 /* Check if running on Xen version (major, minor) or later */ 281 bool 282 xen_running_on_version_or_later(unsigned int major, unsigned int minor) 283 { 284 unsigned int version; 285 286 if (!xen_domain()) 287 return false; 288 289 version = HYPERVISOR_xen_version(XENVER_version, NULL); 290 if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) || 291 ((version >> 16) > major)) 292 return true; 293 return false; 294 } 295 296 #define CPUID_THERM_POWER_LEAF 6 297 #define APERFMPERF_PRESENT 0 298 299 static __read_mostly unsigned int cpuid_leaf1_edx_mask = ~0; 300 static __read_mostly unsigned int cpuid_leaf1_ecx_mask = ~0; 301 302 static __read_mostly unsigned int cpuid_leaf1_ecx_set_mask; 303 static __read_mostly unsigned int cpuid_leaf5_ecx_val; 304 static __read_mostly unsigned int cpuid_leaf5_edx_val; 305 306 static void xen_cpuid(unsigned int *ax, unsigned int *bx, 307 unsigned int *cx, unsigned int *dx) 308 { 309 unsigned maskebx = ~0; 310 unsigned maskecx = ~0; 311 unsigned maskedx = ~0; 312 unsigned setecx = 0; 313 /* 314 * Mask out inconvenient features, to try and disable as many 315 * unsupported kernel subsystems as possible. 316 */ 317 switch (*ax) { 318 case 1: 319 maskecx = cpuid_leaf1_ecx_mask; 320 setecx = cpuid_leaf1_ecx_set_mask; 321 maskedx = cpuid_leaf1_edx_mask; 322 break; 323 324 case CPUID_MWAIT_LEAF: 325 /* Synthesize the values.. */ 326 *ax = 0; 327 *bx = 0; 328 *cx = cpuid_leaf5_ecx_val; 329 *dx = cpuid_leaf5_edx_val; 330 return; 331 332 case CPUID_THERM_POWER_LEAF: 333 /* Disabling APERFMPERF for kernel usage */ 334 maskecx = ~(1 << APERFMPERF_PRESENT); 335 break; 336 337 case 0xb: 338 /* Suppress extended topology stuff */ 339 maskebx = 0; 340 break; 341 } 342 343 asm(XEN_EMULATE_PREFIX "cpuid" 344 : "=a" (*ax), 345 "=b" (*bx), 346 "=c" (*cx), 347 "=d" (*dx) 348 : "0" (*ax), "2" (*cx)); 349 350 *bx &= maskebx; 351 *cx &= maskecx; 352 *cx |= setecx; 353 *dx &= maskedx; 354 } 355 STACK_FRAME_NON_STANDARD(xen_cpuid); /* XEN_EMULATE_PREFIX */ 356 357 static bool __init xen_check_mwait(void) 358 { 359 #ifdef CONFIG_ACPI 360 struct xen_platform_op op = { 361 .cmd = XENPF_set_processor_pminfo, 362 .u.set_pminfo.id = -1, 363 .u.set_pminfo.type = XEN_PM_PDC, 364 }; 365 uint32_t buf[3]; 366 unsigned int ax, bx, cx, dx; 367 unsigned int mwait_mask; 368 369 /* We need to determine whether it is OK to expose the MWAIT 370 * capability to the kernel to harvest deeper than C3 states from ACPI 371 * _CST using the processor_harvest_xen.c module. For this to work, we 372 * need to gather the MWAIT_LEAF values (which the cstate.c code 373 * checks against). The hypervisor won't expose the MWAIT flag because 374 * it would break backwards compatibility; so we will find out directly 375 * from the hardware and hypercall. 376 */ 377 if (!xen_initial_domain()) 378 return false; 379 380 /* 381 * When running under platform earlier than Xen4.2, do not expose 382 * mwait, to avoid the risk of loading native acpi pad driver 383 */ 384 if (!xen_running_on_version_or_later(4, 2)) 385 return false; 386 387 ax = 1; 388 cx = 0; 389 390 native_cpuid(&ax, &bx, &cx, &dx); 391 392 mwait_mask = (1 << (X86_FEATURE_EST % 32)) | 393 (1 << (X86_FEATURE_MWAIT % 32)); 394 395 if ((cx & mwait_mask) != mwait_mask) 396 return false; 397 398 /* We need to emulate the MWAIT_LEAF and for that we need both 399 * ecx and edx. The hypercall provides only partial information. 400 */ 401 402 ax = CPUID_MWAIT_LEAF; 403 bx = 0; 404 cx = 0; 405 dx = 0; 406 407 native_cpuid(&ax, &bx, &cx, &dx); 408 409 /* Ask the Hypervisor whether to clear ACPI_PDC_C_C2C3_FFH. If so, 410 * don't expose MWAIT_LEAF and let ACPI pick the IOPORT version of C3. 411 */ 412 buf[0] = ACPI_PDC_REVISION_ID; 413 buf[1] = 1; 414 buf[2] = (ACPI_PDC_C_CAPABILITY_SMP | ACPI_PDC_EST_CAPABILITY_SWSMP); 415 416 set_xen_guest_handle(op.u.set_pminfo.pdc, buf); 417 418 if ((HYPERVISOR_platform_op(&op) == 0) && 419 (buf[2] & (ACPI_PDC_C_C1_FFH | ACPI_PDC_C_C2C3_FFH))) { 420 cpuid_leaf5_ecx_val = cx; 421 cpuid_leaf5_edx_val = dx; 422 } 423 return true; 424 #else 425 return false; 426 #endif 427 } 428 static void __init xen_init_cpuid_mask(void) 429 { 430 unsigned int ax, bx, cx, dx; 431 unsigned int xsave_mask; 432 433 cpuid_leaf1_edx_mask = 434 ~((1 << X86_FEATURE_MTRR) | /* disable MTRR */ 435 (1 << X86_FEATURE_ACC)); /* thermal monitoring */ 436 437 if (!xen_initial_domain()) 438 cpuid_leaf1_edx_mask &= 439 ~((1 << X86_FEATURE_ACPI)); /* disable ACPI */ 440 441 cpuid_leaf1_ecx_mask &= ~(1 << (X86_FEATURE_X2APIC % 32)); 442 443 ax = 1; 444 cx = 0; 445 cpuid(1, &ax, &bx, &cx, &dx); 446 447 xsave_mask = 448 (1 << (X86_FEATURE_XSAVE % 32)) | 449 (1 << (X86_FEATURE_OSXSAVE % 32)); 450 451 /* Xen will set CR4.OSXSAVE if supported and not disabled by force */ 452 if ((cx & xsave_mask) != xsave_mask) 453 cpuid_leaf1_ecx_mask &= ~xsave_mask; /* disable XSAVE & OSXSAVE */ 454 if (xen_check_mwait()) 455 cpuid_leaf1_ecx_set_mask = (1 << (X86_FEATURE_MWAIT % 32)); 456 } 457 458 static void xen_set_debugreg(int reg, unsigned long val) 459 { 460 HYPERVISOR_set_debugreg(reg, val); 461 } 462 463 static unsigned long xen_get_debugreg(int reg) 464 { 465 return HYPERVISOR_get_debugreg(reg); 466 } 467 468 static void xen_end_context_switch(struct task_struct *next) 469 { 470 xen_mc_flush(); 471 paravirt_end_context_switch(next); 472 } 473 474 static unsigned long xen_store_tr(void) 475 { 476 return 0; 477 } 478 479 /* 480 * Set the page permissions for a particular virtual address. If the 481 * address is a vmalloc mapping (or other non-linear mapping), then 482 * find the linear mapping of the page and also set its protections to 483 * match. 484 */ 485 static void set_aliased_prot(void *v, pgprot_t prot) 486 { 487 int level; 488 pte_t *ptep; 489 pte_t pte; 490 unsigned long pfn; 491 struct page *page; 492 unsigned char dummy; 493 494 ptep = lookup_address((unsigned long)v, &level); 495 BUG_ON(ptep == NULL); 496 497 pfn = pte_pfn(*ptep); 498 page = pfn_to_page(pfn); 499 500 pte = pfn_pte(pfn, prot); 501 502 /* 503 * Careful: update_va_mapping() will fail if the virtual address 504 * we're poking isn't populated in the page tables. We don't 505 * need to worry about the direct map (that's always in the page 506 * tables), but we need to be careful about vmap space. In 507 * particular, the top level page table can lazily propagate 508 * entries between processes, so if we've switched mms since we 509 * vmapped the target in the first place, we might not have the 510 * top-level page table entry populated. 511 * 512 * We disable preemption because we want the same mm active when 513 * we probe the target and when we issue the hypercall. We'll 514 * have the same nominal mm, but if we're a kernel thread, lazy 515 * mm dropping could change our pgd. 516 * 517 * Out of an abundance of caution, this uses __get_user() to fault 518 * in the target address just in case there's some obscure case 519 * in which the target address isn't readable. 520 */ 521 522 preempt_disable(); 523 524 pagefault_disable(); /* Avoid warnings due to being atomic. */ 525 __get_user(dummy, (unsigned char __user __force *)v); 526 pagefault_enable(); 527 528 if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0)) 529 BUG(); 530 531 if (!PageHighMem(page)) { 532 void *av = __va(PFN_PHYS(pfn)); 533 534 if (av != v) 535 if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0)) 536 BUG(); 537 } else 538 kmap_flush_unused(); 539 540 preempt_enable(); 541 } 542 543 static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries) 544 { 545 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE; 546 int i; 547 548 /* 549 * We need to mark the all aliases of the LDT pages RO. We 550 * don't need to call vm_flush_aliases(), though, since that's 551 * only responsible for flushing aliases out the TLBs, not the 552 * page tables, and Xen will flush the TLB for us if needed. 553 * 554 * To avoid confusing future readers: none of this is necessary 555 * to load the LDT. The hypervisor only checks this when the 556 * LDT is faulted in due to subsequent descriptor access. 557 */ 558 559 for(i = 0; i < entries; i += entries_per_page) 560 set_aliased_prot(ldt + i, PAGE_KERNEL_RO); 561 } 562 563 static void xen_free_ldt(struct desc_struct *ldt, unsigned entries) 564 { 565 const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE; 566 int i; 567 568 for(i = 0; i < entries; i += entries_per_page) 569 set_aliased_prot(ldt + i, PAGE_KERNEL); 570 } 571 572 static void xen_set_ldt(const void *addr, unsigned entries) 573 { 574 struct mmuext_op *op; 575 struct multicall_space mcs = xen_mc_entry(sizeof(*op)); 576 577 trace_xen_cpu_set_ldt(addr, entries); 578 579 op = mcs.args; 580 op->cmd = MMUEXT_SET_LDT; 581 op->arg1.linear_addr = (unsigned long)addr; 582 op->arg2.nr_ents = entries; 583 584 MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF); 585 586 xen_mc_issue(PARAVIRT_LAZY_CPU); 587 } 588 589 static void xen_load_gdt(const struct desc_ptr *dtr) 590 { 591 unsigned long va = dtr->address; 592 unsigned int size = dtr->size + 1; 593 unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE; 594 unsigned long frames[pages]; 595 int f; 596 597 /* 598 * A GDT can be up to 64k in size, which corresponds to 8192 599 * 8-byte entries, or 16 4k pages.. 600 */ 601 602 BUG_ON(size > 65536); 603 BUG_ON(va & ~PAGE_MASK); 604 605 for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { 606 int level; 607 pte_t *ptep; 608 unsigned long pfn, mfn; 609 void *virt; 610 611 /* 612 * The GDT is per-cpu and is in the percpu data area. 613 * That can be virtually mapped, so we need to do a 614 * page-walk to get the underlying MFN for the 615 * hypercall. The page can also be in the kernel's 616 * linear range, so we need to RO that mapping too. 617 */ 618 ptep = lookup_address(va, &level); 619 BUG_ON(ptep == NULL); 620 621 pfn = pte_pfn(*ptep); 622 mfn = pfn_to_mfn(pfn); 623 virt = __va(PFN_PHYS(pfn)); 624 625 frames[f] = mfn; 626 627 make_lowmem_page_readonly((void *)va); 628 make_lowmem_page_readonly(virt); 629 } 630 631 if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct))) 632 BUG(); 633 } 634 635 /* 636 * load_gdt for early boot, when the gdt is only mapped once 637 */ 638 static void __init xen_load_gdt_boot(const struct desc_ptr *dtr) 639 { 640 unsigned long va = dtr->address; 641 unsigned int size = dtr->size + 1; 642 unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE; 643 unsigned long frames[pages]; 644 int f; 645 646 /* 647 * A GDT can be up to 64k in size, which corresponds to 8192 648 * 8-byte entries, or 16 4k pages.. 649 */ 650 651 BUG_ON(size > 65536); 652 BUG_ON(va & ~PAGE_MASK); 653 654 for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) { 655 pte_t pte; 656 unsigned long pfn, mfn; 657 658 pfn = virt_to_pfn(va); 659 mfn = pfn_to_mfn(pfn); 660 661 pte = pfn_pte(pfn, PAGE_KERNEL_RO); 662 663 if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0)) 664 BUG(); 665 666 frames[f] = mfn; 667 } 668 669 if (HYPERVISOR_set_gdt(frames, size / sizeof(struct desc_struct))) 670 BUG(); 671 } 672 673 static inline bool desc_equal(const struct desc_struct *d1, 674 const struct desc_struct *d2) 675 { 676 return d1->a == d2->a && d1->b == d2->b; 677 } 678 679 static void load_TLS_descriptor(struct thread_struct *t, 680 unsigned int cpu, unsigned int i) 681 { 682 struct desc_struct *shadow = &per_cpu(shadow_tls_desc, cpu).desc[i]; 683 struct desc_struct *gdt; 684 xmaddr_t maddr; 685 struct multicall_space mc; 686 687 if (desc_equal(shadow, &t->tls_array[i])) 688 return; 689 690 *shadow = t->tls_array[i]; 691 692 gdt = get_cpu_gdt_table(cpu); 693 maddr = arbitrary_virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]); 694 mc = __xen_mc_entry(0); 695 696 MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]); 697 } 698 699 static void xen_load_tls(struct thread_struct *t, unsigned int cpu) 700 { 701 /* 702 * XXX sleazy hack: If we're being called in a lazy-cpu zone 703 * and lazy gs handling is enabled, it means we're in a 704 * context switch, and %gs has just been saved. This means we 705 * can zero it out to prevent faults on exit from the 706 * hypervisor if the next process has no %gs. Either way, it 707 * has been saved, and the new value will get loaded properly. 708 * This will go away as soon as Xen has been modified to not 709 * save/restore %gs for normal hypercalls. 710 * 711 * On x86_64, this hack is not used for %gs, because gs points 712 * to KERNEL_GS_BASE (and uses it for PDA references), so we 713 * must not zero %gs on x86_64 714 * 715 * For x86_64, we need to zero %fs, otherwise we may get an 716 * exception between the new %fs descriptor being loaded and 717 * %fs being effectively cleared at __switch_to(). 718 */ 719 if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) { 720 #ifdef CONFIG_X86_32 721 lazy_load_gs(0); 722 #else 723 loadsegment(fs, 0); 724 #endif 725 } 726 727 xen_mc_batch(); 728 729 load_TLS_descriptor(t, cpu, 0); 730 load_TLS_descriptor(t, cpu, 1); 731 load_TLS_descriptor(t, cpu, 2); 732 733 xen_mc_issue(PARAVIRT_LAZY_CPU); 734 } 735 736 #ifdef CONFIG_X86_64 737 static void xen_load_gs_index(unsigned int idx) 738 { 739 if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx)) 740 BUG(); 741 } 742 #endif 743 744 static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum, 745 const void *ptr) 746 { 747 xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]); 748 u64 entry = *(u64 *)ptr; 749 750 trace_xen_cpu_write_ldt_entry(dt, entrynum, entry); 751 752 preempt_disable(); 753 754 xen_mc_flush(); 755 if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry)) 756 BUG(); 757 758 preempt_enable(); 759 } 760 761 static int cvt_gate_to_trap(int vector, const gate_desc *val, 762 struct trap_info *info) 763 { 764 unsigned long addr; 765 766 if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT) 767 return 0; 768 769 info->vector = vector; 770 771 addr = gate_offset(*val); 772 #ifdef CONFIG_X86_64 773 /* 774 * Look for known traps using IST, and substitute them 775 * appropriately. The debugger ones are the only ones we care 776 * about. Xen will handle faults like double_fault, 777 * so we should never see them. Warn if 778 * there's an unexpected IST-using fault handler. 779 */ 780 if (addr == (unsigned long)debug) 781 addr = (unsigned long)xen_debug; 782 else if (addr == (unsigned long)int3) 783 addr = (unsigned long)xen_int3; 784 else if (addr == (unsigned long)stack_segment) 785 addr = (unsigned long)xen_stack_segment; 786 else if (addr == (unsigned long)double_fault) { 787 /* Don't need to handle these */ 788 return 0; 789 #ifdef CONFIG_X86_MCE 790 } else if (addr == (unsigned long)machine_check) { 791 /* 792 * when xen hypervisor inject vMCE to guest, 793 * use native mce handler to handle it 794 */ 795 ; 796 #endif 797 } else if (addr == (unsigned long)nmi) 798 /* 799 * Use the native version as well. 800 */ 801 ; 802 else { 803 /* Some other trap using IST? */ 804 if (WARN_ON(val->ist != 0)) 805 return 0; 806 } 807 #endif /* CONFIG_X86_64 */ 808 info->address = addr; 809 810 info->cs = gate_segment(*val); 811 info->flags = val->dpl; 812 /* interrupt gates clear IF */ 813 if (val->type == GATE_INTERRUPT) 814 info->flags |= 1 << 2; 815 816 return 1; 817 } 818 819 /* Locations of each CPU's IDT */ 820 static DEFINE_PER_CPU(struct desc_ptr, idt_desc); 821 822 /* Set an IDT entry. If the entry is part of the current IDT, then 823 also update Xen. */ 824 static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g) 825 { 826 unsigned long p = (unsigned long)&dt[entrynum]; 827 unsigned long start, end; 828 829 trace_xen_cpu_write_idt_entry(dt, entrynum, g); 830 831 preempt_disable(); 832 833 start = __this_cpu_read(idt_desc.address); 834 end = start + __this_cpu_read(idt_desc.size) + 1; 835 836 xen_mc_flush(); 837 838 native_write_idt_entry(dt, entrynum, g); 839 840 if (p >= start && (p + 8) <= end) { 841 struct trap_info info[2]; 842 843 info[1].address = 0; 844 845 if (cvt_gate_to_trap(entrynum, g, &info[0])) 846 if (HYPERVISOR_set_trap_table(info)) 847 BUG(); 848 } 849 850 preempt_enable(); 851 } 852 853 static void xen_convert_trap_info(const struct desc_ptr *desc, 854 struct trap_info *traps) 855 { 856 unsigned in, out, count; 857 858 count = (desc->size+1) / sizeof(gate_desc); 859 BUG_ON(count > 256); 860 861 for (in = out = 0; in < count; in++) { 862 gate_desc *entry = (gate_desc*)(desc->address) + in; 863 864 if (cvt_gate_to_trap(in, entry, &traps[out])) 865 out++; 866 } 867 traps[out].address = 0; 868 } 869 870 void xen_copy_trap_info(struct trap_info *traps) 871 { 872 const struct desc_ptr *desc = this_cpu_ptr(&idt_desc); 873 874 xen_convert_trap_info(desc, traps); 875 } 876 877 /* Load a new IDT into Xen. In principle this can be per-CPU, so we 878 hold a spinlock to protect the static traps[] array (static because 879 it avoids allocation, and saves stack space). */ 880 static void xen_load_idt(const struct desc_ptr *desc) 881 { 882 static DEFINE_SPINLOCK(lock); 883 static struct trap_info traps[257]; 884 885 trace_xen_cpu_load_idt(desc); 886 887 spin_lock(&lock); 888 889 memcpy(this_cpu_ptr(&idt_desc), desc, sizeof(idt_desc)); 890 891 xen_convert_trap_info(desc, traps); 892 893 xen_mc_flush(); 894 if (HYPERVISOR_set_trap_table(traps)) 895 BUG(); 896 897 spin_unlock(&lock); 898 } 899 900 /* Write a GDT descriptor entry. Ignore LDT descriptors, since 901 they're handled differently. */ 902 static void xen_write_gdt_entry(struct desc_struct *dt, int entry, 903 const void *desc, int type) 904 { 905 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type); 906 907 preempt_disable(); 908 909 switch (type) { 910 case DESC_LDT: 911 case DESC_TSS: 912 /* ignore */ 913 break; 914 915 default: { 916 xmaddr_t maddr = arbitrary_virt_to_machine(&dt[entry]); 917 918 xen_mc_flush(); 919 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc)) 920 BUG(); 921 } 922 923 } 924 925 preempt_enable(); 926 } 927 928 /* 929 * Version of write_gdt_entry for use at early boot-time needed to 930 * update an entry as simply as possible. 931 */ 932 static void __init xen_write_gdt_entry_boot(struct desc_struct *dt, int entry, 933 const void *desc, int type) 934 { 935 trace_xen_cpu_write_gdt_entry(dt, entry, desc, type); 936 937 switch (type) { 938 case DESC_LDT: 939 case DESC_TSS: 940 /* ignore */ 941 break; 942 943 default: { 944 xmaddr_t maddr = virt_to_machine(&dt[entry]); 945 946 if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc)) 947 dt[entry] = *(struct desc_struct *)desc; 948 } 949 950 } 951 } 952 953 static void xen_load_sp0(struct tss_struct *tss, 954 struct thread_struct *thread) 955 { 956 struct multicall_space mcs; 957 958 mcs = xen_mc_entry(0); 959 MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->sp0); 960 xen_mc_issue(PARAVIRT_LAZY_CPU); 961 tss->x86_tss.sp0 = thread->sp0; 962 } 963 964 void xen_set_iopl_mask(unsigned mask) 965 { 966 struct physdev_set_iopl set_iopl; 967 968 /* Force the change at ring 0. */ 969 set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3; 970 HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); 971 } 972 973 static void xen_io_delay(void) 974 { 975 } 976 977 static void xen_clts(void) 978 { 979 struct multicall_space mcs; 980 981 mcs = xen_mc_entry(0); 982 983 MULTI_fpu_taskswitch(mcs.mc, 0); 984 985 xen_mc_issue(PARAVIRT_LAZY_CPU); 986 } 987 988 static DEFINE_PER_CPU(unsigned long, xen_cr0_value); 989 990 static unsigned long xen_read_cr0(void) 991 { 992 unsigned long cr0 = this_cpu_read(xen_cr0_value); 993 994 if (unlikely(cr0 == 0)) { 995 cr0 = native_read_cr0(); 996 this_cpu_write(xen_cr0_value, cr0); 997 } 998 999 return cr0; 1000 } 1001 1002 static void xen_write_cr0(unsigned long cr0) 1003 { 1004 struct multicall_space mcs; 1005 1006 this_cpu_write(xen_cr0_value, cr0); 1007 1008 /* Only pay attention to cr0.TS; everything else is 1009 ignored. */ 1010 mcs = xen_mc_entry(0); 1011 1012 MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0); 1013 1014 xen_mc_issue(PARAVIRT_LAZY_CPU); 1015 } 1016 1017 static void xen_write_cr4(unsigned long cr4) 1018 { 1019 cr4 &= ~(X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PCE); 1020 1021 native_write_cr4(cr4); 1022 } 1023 #ifdef CONFIG_X86_64 1024 static inline unsigned long xen_read_cr8(void) 1025 { 1026 return 0; 1027 } 1028 static inline void xen_write_cr8(unsigned long val) 1029 { 1030 BUG_ON(val); 1031 } 1032 #endif 1033 1034 static u64 xen_read_msr_safe(unsigned int msr, int *err) 1035 { 1036 u64 val; 1037 1038 if (pmu_msr_read(msr, &val, err)) 1039 return val; 1040 1041 val = native_read_msr_safe(msr, err); 1042 switch (msr) { 1043 case MSR_IA32_APICBASE: 1044 #ifdef CONFIG_X86_X2APIC 1045 if (!(cpuid_ecx(1) & (1 << (X86_FEATURE_X2APIC & 31)))) 1046 #endif 1047 val &= ~X2APIC_ENABLE; 1048 break; 1049 } 1050 return val; 1051 } 1052 1053 static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high) 1054 { 1055 int ret; 1056 1057 ret = 0; 1058 1059 switch (msr) { 1060 #ifdef CONFIG_X86_64 1061 unsigned which; 1062 u64 base; 1063 1064 case MSR_FS_BASE: which = SEGBASE_FS; goto set; 1065 case MSR_KERNEL_GS_BASE: which = SEGBASE_GS_USER; goto set; 1066 case MSR_GS_BASE: which = SEGBASE_GS_KERNEL; goto set; 1067 1068 set: 1069 base = ((u64)high << 32) | low; 1070 if (HYPERVISOR_set_segment_base(which, base) != 0) 1071 ret = -EIO; 1072 break; 1073 #endif 1074 1075 case MSR_STAR: 1076 case MSR_CSTAR: 1077 case MSR_LSTAR: 1078 case MSR_SYSCALL_MASK: 1079 case MSR_IA32_SYSENTER_CS: 1080 case MSR_IA32_SYSENTER_ESP: 1081 case MSR_IA32_SYSENTER_EIP: 1082 /* Fast syscall setup is all done in hypercalls, so 1083 these are all ignored. Stub them out here to stop 1084 Xen console noise. */ 1085 break; 1086 1087 default: 1088 if (!pmu_msr_write(msr, low, high, &ret)) 1089 ret = native_write_msr_safe(msr, low, high); 1090 } 1091 1092 return ret; 1093 } 1094 1095 static u64 xen_read_msr(unsigned int msr) 1096 { 1097 /* 1098 * This will silently swallow a #GP from RDMSR. It may be worth 1099 * changing that. 1100 */ 1101 int err; 1102 1103 return xen_read_msr_safe(msr, &err); 1104 } 1105 1106 static void xen_write_msr(unsigned int msr, unsigned low, unsigned high) 1107 { 1108 /* 1109 * This will silently swallow a #GP from WRMSR. It may be worth 1110 * changing that. 1111 */ 1112 xen_write_msr_safe(msr, low, high); 1113 } 1114 1115 void xen_setup_shared_info(void) 1116 { 1117 if (!xen_feature(XENFEAT_auto_translated_physmap)) { 1118 set_fixmap(FIX_PARAVIRT_BOOTMAP, 1119 xen_start_info->shared_info); 1120 1121 HYPERVISOR_shared_info = 1122 (struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP); 1123 } else 1124 HYPERVISOR_shared_info = 1125 (struct shared_info *)__va(xen_start_info->shared_info); 1126 1127 #ifndef CONFIG_SMP 1128 /* In UP this is as good a place as any to set up shared info */ 1129 xen_setup_vcpu_info_placement(); 1130 #endif 1131 1132 xen_setup_mfn_list_list(); 1133 } 1134 1135 /* This is called once we have the cpu_possible_mask */ 1136 void xen_setup_vcpu_info_placement(void) 1137 { 1138 int cpu; 1139 1140 for_each_possible_cpu(cpu) 1141 xen_vcpu_setup(cpu); 1142 1143 /* xen_vcpu_setup managed to place the vcpu_info within the 1144 * percpu area for all cpus, so make use of it. Note that for 1145 * PVH we want to use native IRQ mechanism. */ 1146 if (have_vcpu_info_placement && !xen_pvh_domain()) { 1147 pv_irq_ops.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct); 1148 pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(xen_restore_fl_direct); 1149 pv_irq_ops.irq_disable = __PV_IS_CALLEE_SAVE(xen_irq_disable_direct); 1150 pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct); 1151 pv_mmu_ops.read_cr2 = xen_read_cr2_direct; 1152 } 1153 } 1154 1155 static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf, 1156 unsigned long addr, unsigned len) 1157 { 1158 char *start, *end, *reloc; 1159 unsigned ret; 1160 1161 start = end = reloc = NULL; 1162 1163 #define SITE(op, x) \ 1164 case PARAVIRT_PATCH(op.x): \ 1165 if (have_vcpu_info_placement) { \ 1166 start = (char *)xen_##x##_direct; \ 1167 end = xen_##x##_direct_end; \ 1168 reloc = xen_##x##_direct_reloc; \ 1169 } \ 1170 goto patch_site 1171 1172 switch (type) { 1173 SITE(pv_irq_ops, irq_enable); 1174 SITE(pv_irq_ops, irq_disable); 1175 SITE(pv_irq_ops, save_fl); 1176 SITE(pv_irq_ops, restore_fl); 1177 #undef SITE 1178 1179 patch_site: 1180 if (start == NULL || (end-start) > len) 1181 goto default_patch; 1182 1183 ret = paravirt_patch_insns(insnbuf, len, start, end); 1184 1185 /* Note: because reloc is assigned from something that 1186 appears to be an array, gcc assumes it's non-null, 1187 but doesn't know its relationship with start and 1188 end. */ 1189 if (reloc > start && reloc < end) { 1190 int reloc_off = reloc - start; 1191 long *relocp = (long *)(insnbuf + reloc_off); 1192 long delta = start - (char *)addr; 1193 1194 *relocp += delta; 1195 } 1196 break; 1197 1198 default_patch: 1199 default: 1200 ret = paravirt_patch_default(type, clobbers, insnbuf, 1201 addr, len); 1202 break; 1203 } 1204 1205 return ret; 1206 } 1207 1208 static const struct pv_info xen_info __initconst = { 1209 .shared_kernel_pmd = 0, 1210 1211 #ifdef CONFIG_X86_64 1212 .extra_user_64bit_cs = FLAT_USER_CS64, 1213 #endif 1214 .name = "Xen", 1215 }; 1216 1217 static const struct pv_init_ops xen_init_ops __initconst = { 1218 .patch = xen_patch, 1219 }; 1220 1221 static const struct pv_cpu_ops xen_cpu_ops __initconst = { 1222 .cpuid = xen_cpuid, 1223 1224 .set_debugreg = xen_set_debugreg, 1225 .get_debugreg = xen_get_debugreg, 1226 1227 .clts = xen_clts, 1228 1229 .read_cr0 = xen_read_cr0, 1230 .write_cr0 = xen_write_cr0, 1231 1232 .read_cr4 = native_read_cr4, 1233 .read_cr4_safe = native_read_cr4_safe, 1234 .write_cr4 = xen_write_cr4, 1235 1236 #ifdef CONFIG_X86_64 1237 .read_cr8 = xen_read_cr8, 1238 .write_cr8 = xen_write_cr8, 1239 #endif 1240 1241 .wbinvd = native_wbinvd, 1242 1243 .read_msr = xen_read_msr, 1244 .write_msr = xen_write_msr, 1245 1246 .read_msr_safe = xen_read_msr_safe, 1247 .write_msr_safe = xen_write_msr_safe, 1248 1249 .read_pmc = xen_read_pmc, 1250 1251 .iret = xen_iret, 1252 #ifdef CONFIG_X86_64 1253 .usergs_sysret64 = xen_sysret64, 1254 #endif 1255 1256 .load_tr_desc = paravirt_nop, 1257 .set_ldt = xen_set_ldt, 1258 .load_gdt = xen_load_gdt, 1259 .load_idt = xen_load_idt, 1260 .load_tls = xen_load_tls, 1261 #ifdef CONFIG_X86_64 1262 .load_gs_index = xen_load_gs_index, 1263 #endif 1264 1265 .alloc_ldt = xen_alloc_ldt, 1266 .free_ldt = xen_free_ldt, 1267 1268 .store_idt = native_store_idt, 1269 .store_tr = xen_store_tr, 1270 1271 .write_ldt_entry = xen_write_ldt_entry, 1272 .write_gdt_entry = xen_write_gdt_entry, 1273 .write_idt_entry = xen_write_idt_entry, 1274 .load_sp0 = xen_load_sp0, 1275 1276 .set_iopl_mask = xen_set_iopl_mask, 1277 .io_delay = xen_io_delay, 1278 1279 /* Xen takes care of %gs when switching to usermode for us */ 1280 .swapgs = paravirt_nop, 1281 1282 .start_context_switch = paravirt_start_context_switch, 1283 .end_context_switch = xen_end_context_switch, 1284 }; 1285 1286 static void xen_reboot(int reason) 1287 { 1288 struct sched_shutdown r = { .reason = reason }; 1289 int cpu; 1290 1291 for_each_online_cpu(cpu) 1292 xen_pmu_finish(cpu); 1293 1294 if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r)) 1295 BUG(); 1296 } 1297 1298 static void xen_restart(char *msg) 1299 { 1300 xen_reboot(SHUTDOWN_reboot); 1301 } 1302 1303 static void xen_emergency_restart(void) 1304 { 1305 xen_reboot(SHUTDOWN_reboot); 1306 } 1307 1308 static void xen_machine_halt(void) 1309 { 1310 xen_reboot(SHUTDOWN_poweroff); 1311 } 1312 1313 static void xen_machine_power_off(void) 1314 { 1315 if (pm_power_off) 1316 pm_power_off(); 1317 xen_reboot(SHUTDOWN_poweroff); 1318 } 1319 1320 static void xen_crash_shutdown(struct pt_regs *regs) 1321 { 1322 xen_reboot(SHUTDOWN_crash); 1323 } 1324 1325 static int 1326 xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr) 1327 { 1328 xen_reboot(SHUTDOWN_crash); 1329 return NOTIFY_DONE; 1330 } 1331 1332 static struct notifier_block xen_panic_block = { 1333 .notifier_call= xen_panic_event, 1334 .priority = INT_MIN 1335 }; 1336 1337 int xen_panic_handler_init(void) 1338 { 1339 atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block); 1340 return 0; 1341 } 1342 1343 static const struct machine_ops xen_machine_ops __initconst = { 1344 .restart = xen_restart, 1345 .halt = xen_machine_halt, 1346 .power_off = xen_machine_power_off, 1347 .shutdown = xen_machine_halt, 1348 .crash_shutdown = xen_crash_shutdown, 1349 .emergency_restart = xen_emergency_restart, 1350 }; 1351 1352 static unsigned char xen_get_nmi_reason(void) 1353 { 1354 unsigned char reason = 0; 1355 1356 /* Construct a value which looks like it came from port 0x61. */ 1357 if (test_bit(_XEN_NMIREASON_io_error, 1358 &HYPERVISOR_shared_info->arch.nmi_reason)) 1359 reason |= NMI_REASON_IOCHK; 1360 if (test_bit(_XEN_NMIREASON_pci_serr, 1361 &HYPERVISOR_shared_info->arch.nmi_reason)) 1362 reason |= NMI_REASON_SERR; 1363 1364 return reason; 1365 } 1366 1367 static void __init xen_boot_params_init_edd(void) 1368 { 1369 #if IS_ENABLED(CONFIG_EDD) 1370 struct xen_platform_op op; 1371 struct edd_info *edd_info; 1372 u32 *mbr_signature; 1373 unsigned nr; 1374 int ret; 1375 1376 edd_info = boot_params.eddbuf; 1377 mbr_signature = boot_params.edd_mbr_sig_buffer; 1378 1379 op.cmd = XENPF_firmware_info; 1380 1381 op.u.firmware_info.type = XEN_FW_DISK_INFO; 1382 for (nr = 0; nr < EDDMAXNR; nr++) { 1383 struct edd_info *info = edd_info + nr; 1384 1385 op.u.firmware_info.index = nr; 1386 info->params.length = sizeof(info->params); 1387 set_xen_guest_handle(op.u.firmware_info.u.disk_info.edd_params, 1388 &info->params); 1389 ret = HYPERVISOR_platform_op(&op); 1390 if (ret) 1391 break; 1392 1393 #define C(x) info->x = op.u.firmware_info.u.disk_info.x 1394 C(device); 1395 C(version); 1396 C(interface_support); 1397 C(legacy_max_cylinder); 1398 C(legacy_max_head); 1399 C(legacy_sectors_per_track); 1400 #undef C 1401 } 1402 boot_params.eddbuf_entries = nr; 1403 1404 op.u.firmware_info.type = XEN_FW_DISK_MBR_SIGNATURE; 1405 for (nr = 0; nr < EDD_MBR_SIG_MAX; nr++) { 1406 op.u.firmware_info.index = nr; 1407 ret = HYPERVISOR_platform_op(&op); 1408 if (ret) 1409 break; 1410 mbr_signature[nr] = op.u.firmware_info.u.disk_mbr_signature.mbr_signature; 1411 } 1412 boot_params.edd_mbr_sig_buf_entries = nr; 1413 #endif 1414 } 1415 1416 /* 1417 * Set up the GDT and segment registers for -fstack-protector. Until 1418 * we do this, we have to be careful not to call any stack-protected 1419 * function, which is most of the kernel. 1420 * 1421 * Note, that it is __ref because the only caller of this after init 1422 * is PVH which is not going to use xen_load_gdt_boot or other 1423 * __init functions. 1424 */ 1425 static void __ref xen_setup_gdt(int cpu) 1426 { 1427 if (xen_feature(XENFEAT_auto_translated_physmap)) { 1428 #ifdef CONFIG_X86_64 1429 unsigned long dummy; 1430 1431 load_percpu_segment(cpu); /* We need to access per-cpu area */ 1432 switch_to_new_gdt(cpu); /* GDT and GS set */ 1433 1434 /* We are switching of the Xen provided GDT to our HVM mode 1435 * GDT. The new GDT has __KERNEL_CS with CS.L = 1 1436 * and we are jumping to reload it. 1437 */ 1438 asm volatile ("pushq %0\n" 1439 "leaq 1f(%%rip),%0\n" 1440 "pushq %0\n" 1441 "lretq\n" 1442 "1:\n" 1443 : "=&r" (dummy) : "0" (__KERNEL_CS)); 1444 1445 /* 1446 * While not needed, we also set the %es, %ds, and %fs 1447 * to zero. We don't care about %ss as it is NULL. 1448 * Strictly speaking this is not needed as Xen zeros those 1449 * out (and also MSR_FS_BASE, MSR_GS_BASE, MSR_KERNEL_GS_BASE) 1450 * 1451 * Linux zeros them in cpu_init() and in secondary_startup_64 1452 * (for BSP). 1453 */ 1454 loadsegment(es, 0); 1455 loadsegment(ds, 0); 1456 loadsegment(fs, 0); 1457 #else 1458 /* PVH: TODO Implement. */ 1459 BUG(); 1460 #endif 1461 return; /* PVH does not need any PV GDT ops. */ 1462 } 1463 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry_boot; 1464 pv_cpu_ops.load_gdt = xen_load_gdt_boot; 1465 1466 setup_stack_canary_segment(0); 1467 switch_to_new_gdt(0); 1468 1469 pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry; 1470 pv_cpu_ops.load_gdt = xen_load_gdt; 1471 } 1472 1473 #ifdef CONFIG_XEN_PVH 1474 /* 1475 * A PV guest starts with default flags that are not set for PVH, set them 1476 * here asap. 1477 */ 1478 static void xen_pvh_set_cr_flags(int cpu) 1479 { 1480 1481 /* Some of these are setup in 'secondary_startup_64'. The others: 1482 * X86_CR0_TS, X86_CR0_PE, X86_CR0_ET are set by Xen for HVM guests 1483 * (which PVH shared codepaths), while X86_CR0_PG is for PVH. */ 1484 write_cr0(read_cr0() | X86_CR0_MP | X86_CR0_NE | X86_CR0_WP | X86_CR0_AM); 1485 1486 if (!cpu) 1487 return; 1488 /* 1489 * For BSP, PSE PGE are set in probe_page_size_mask(), for APs 1490 * set them here. For all, OSFXSR OSXMMEXCPT are set in fpu__init_cpu(). 1491 */ 1492 if (boot_cpu_has(X86_FEATURE_PSE)) 1493 cr4_set_bits_and_update_boot(X86_CR4_PSE); 1494 1495 if (boot_cpu_has(X86_FEATURE_PGE)) 1496 cr4_set_bits_and_update_boot(X86_CR4_PGE); 1497 } 1498 1499 /* 1500 * Note, that it is ref - because the only caller of this after init 1501 * is PVH which is not going to use xen_load_gdt_boot or other 1502 * __init functions. 1503 */ 1504 void __ref xen_pvh_secondary_vcpu_init(int cpu) 1505 { 1506 xen_setup_gdt(cpu); 1507 xen_pvh_set_cr_flags(cpu); 1508 } 1509 1510 static void __init xen_pvh_early_guest_init(void) 1511 { 1512 if (!xen_feature(XENFEAT_auto_translated_physmap)) 1513 return; 1514 1515 if (!xen_feature(XENFEAT_hvm_callback_vector)) 1516 return; 1517 1518 xen_have_vector_callback = 1; 1519 1520 xen_pvh_early_cpu_init(0, false); 1521 xen_pvh_set_cr_flags(0); 1522 1523 #ifdef CONFIG_X86_32 1524 BUG(); /* PVH: Implement proper support. */ 1525 #endif 1526 } 1527 #endif /* CONFIG_XEN_PVH */ 1528 1529 static void __init xen_dom0_set_legacy_features(void) 1530 { 1531 x86_platform.legacy.rtc = 1; 1532 } 1533 1534 /* First C function to be called on Xen boot */ 1535 asmlinkage __visible void __init xen_start_kernel(void) 1536 { 1537 struct physdev_set_iopl set_iopl; 1538 unsigned long initrd_start = 0; 1539 int rc; 1540 1541 if (!xen_start_info) 1542 return; 1543 1544 xen_domain_type = XEN_PV_DOMAIN; 1545 1546 xen_setup_features(); 1547 #ifdef CONFIG_XEN_PVH 1548 xen_pvh_early_guest_init(); 1549 #endif 1550 xen_setup_machphys_mapping(); 1551 1552 /* Install Xen paravirt ops */ 1553 pv_info = xen_info; 1554 pv_init_ops = xen_init_ops; 1555 if (!xen_pvh_domain()) { 1556 pv_cpu_ops = xen_cpu_ops; 1557 1558 x86_platform.get_nmi_reason = xen_get_nmi_reason; 1559 } 1560 1561 if (xen_feature(XENFEAT_auto_translated_physmap)) 1562 x86_init.resources.memory_setup = xen_auto_xlated_memory_setup; 1563 else 1564 x86_init.resources.memory_setup = xen_memory_setup; 1565 x86_init.oem.arch_setup = xen_arch_setup; 1566 x86_init.oem.banner = xen_banner; 1567 1568 xen_init_time_ops(); 1569 1570 /* 1571 * Set up some pagetable state before starting to set any ptes. 1572 */ 1573 1574 xen_init_mmu_ops(); 1575 1576 /* Prevent unwanted bits from being set in PTEs. */ 1577 __supported_pte_mask &= ~_PAGE_GLOBAL; 1578 1579 /* 1580 * Prevent page tables from being allocated in highmem, even 1581 * if CONFIG_HIGHPTE is enabled. 1582 */ 1583 __userpte_alloc_gfp &= ~__GFP_HIGHMEM; 1584 1585 /* Work out if we support NX */ 1586 x86_configure_nx(); 1587 1588 /* Get mfn list */ 1589 xen_build_dynamic_phys_to_machine(); 1590 1591 /* 1592 * Set up kernel GDT and segment registers, mainly so that 1593 * -fstack-protector code can be executed. 1594 */ 1595 xen_setup_gdt(0); 1596 1597 xen_init_irq_ops(); 1598 xen_init_cpuid_mask(); 1599 1600 #ifdef CONFIG_X86_LOCAL_APIC 1601 /* 1602 * set up the basic apic ops. 1603 */ 1604 xen_init_apic(); 1605 #endif 1606 1607 if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) { 1608 pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start; 1609 pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit; 1610 } 1611 1612 machine_ops = xen_machine_ops; 1613 1614 /* 1615 * The only reliable way to retain the initial address of the 1616 * percpu gdt_page is to remember it here, so we can go and 1617 * mark it RW later, when the initial percpu area is freed. 1618 */ 1619 xen_initial_gdt = &per_cpu(gdt_page, 0); 1620 1621 xen_smp_init(); 1622 1623 #ifdef CONFIG_ACPI_NUMA 1624 /* 1625 * The pages we from Xen are not related to machine pages, so 1626 * any NUMA information the kernel tries to get from ACPI will 1627 * be meaningless. Prevent it from trying. 1628 */ 1629 acpi_numa = -1; 1630 #endif 1631 /* Don't do the full vcpu_info placement stuff until we have a 1632 possible map and a non-dummy shared_info. */ 1633 per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0]; 1634 1635 local_irq_disable(); 1636 early_boot_irqs_disabled = true; 1637 1638 xen_raw_console_write("mapping kernel into physical memory\n"); 1639 xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base, 1640 xen_start_info->nr_pages); 1641 xen_reserve_special_pages(); 1642 1643 /* keep using Xen gdt for now; no urgent need to change it */ 1644 1645 #ifdef CONFIG_X86_32 1646 pv_info.kernel_rpl = 1; 1647 if (xen_feature(XENFEAT_supervisor_mode_kernel)) 1648 pv_info.kernel_rpl = 0; 1649 #else 1650 pv_info.kernel_rpl = 0; 1651 #endif 1652 /* set the limit of our address space */ 1653 xen_reserve_top(); 1654 1655 /* PVH: runs at default kernel iopl of 0 */ 1656 if (!xen_pvh_domain()) { 1657 /* 1658 * We used to do this in xen_arch_setup, but that is too late 1659 * on AMD were early_cpu_init (run before ->arch_setup()) calls 1660 * early_amd_init which pokes 0xcf8 port. 1661 */ 1662 set_iopl.iopl = 1; 1663 rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); 1664 if (rc != 0) 1665 xen_raw_printk("physdev_op failed %d\n", rc); 1666 } 1667 1668 #ifdef CONFIG_X86_32 1669 /* set up basic CPUID stuff */ 1670 cpu_detect(&new_cpu_data); 1671 set_cpu_cap(&new_cpu_data, X86_FEATURE_FPU); 1672 new_cpu_data.wp_works_ok = 1; 1673 new_cpu_data.x86_capability[CPUID_1_EDX] = cpuid_edx(1); 1674 #endif 1675 1676 if (xen_start_info->mod_start) { 1677 if (xen_start_info->flags & SIF_MOD_START_PFN) 1678 initrd_start = PFN_PHYS(xen_start_info->mod_start); 1679 else 1680 initrd_start = __pa(xen_start_info->mod_start); 1681 } 1682 1683 /* Poke various useful things into boot_params */ 1684 boot_params.hdr.type_of_loader = (9 << 4) | 0; 1685 boot_params.hdr.ramdisk_image = initrd_start; 1686 boot_params.hdr.ramdisk_size = xen_start_info->mod_len; 1687 boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line); 1688 boot_params.hdr.hardware_subarch = X86_SUBARCH_XEN; 1689 1690 if (!xen_initial_domain()) { 1691 add_preferred_console("xenboot", 0, NULL); 1692 add_preferred_console("tty", 0, NULL); 1693 add_preferred_console("hvc", 0, NULL); 1694 if (pci_xen) 1695 x86_init.pci.arch_init = pci_xen_init; 1696 } else { 1697 const struct dom0_vga_console_info *info = 1698 (void *)((char *)xen_start_info + 1699 xen_start_info->console.dom0.info_off); 1700 struct xen_platform_op op = { 1701 .cmd = XENPF_firmware_info, 1702 .interface_version = XENPF_INTERFACE_VERSION, 1703 .u.firmware_info.type = XEN_FW_KBD_SHIFT_FLAGS, 1704 }; 1705 1706 x86_platform.set_legacy_features = 1707 xen_dom0_set_legacy_features; 1708 xen_init_vga(info, xen_start_info->console.dom0.info_size); 1709 xen_start_info->console.domU.mfn = 0; 1710 xen_start_info->console.domU.evtchn = 0; 1711 1712 if (HYPERVISOR_platform_op(&op) == 0) 1713 boot_params.kbd_status = op.u.firmware_info.u.kbd_shift_flags; 1714 1715 /* Make sure ACS will be enabled */ 1716 pci_request_acs(); 1717 1718 xen_acpi_sleep_register(); 1719 1720 /* Avoid searching for BIOS MP tables */ 1721 x86_init.mpparse.find_smp_config = x86_init_noop; 1722 x86_init.mpparse.get_smp_config = x86_init_uint_noop; 1723 1724 xen_boot_params_init_edd(); 1725 } 1726 #ifdef CONFIG_PCI 1727 /* PCI BIOS service won't work from a PV guest. */ 1728 pci_probe &= ~PCI_PROBE_BIOS; 1729 #endif 1730 xen_raw_console_write("about to get started...\n"); 1731 1732 xen_setup_runstate_info(0); 1733 1734 xen_efi_init(); 1735 1736 /* Start the world */ 1737 #ifdef CONFIG_X86_32 1738 i386_start_kernel(); 1739 #else 1740 cr4_init_shadow(); /* 32b kernel does this in i386_start_kernel() */ 1741 x86_64_start_reservations((char *)__pa_symbol(&boot_params)); 1742 #endif 1743 } 1744 1745 void __ref xen_hvm_init_shared_info(void) 1746 { 1747 int cpu; 1748 struct xen_add_to_physmap xatp; 1749 static struct shared_info *shared_info_page = 0; 1750 1751 if (!shared_info_page) 1752 shared_info_page = (struct shared_info *) 1753 extend_brk(PAGE_SIZE, PAGE_SIZE); 1754 xatp.domid = DOMID_SELF; 1755 xatp.idx = 0; 1756 xatp.space = XENMAPSPACE_shared_info; 1757 xatp.gpfn = __pa(shared_info_page) >> PAGE_SHIFT; 1758 if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp)) 1759 BUG(); 1760 1761 HYPERVISOR_shared_info = (struct shared_info *)shared_info_page; 1762 1763 /* xen_vcpu is a pointer to the vcpu_info struct in the shared_info 1764 * page, we use it in the event channel upcall and in some pvclock 1765 * related functions. We don't need the vcpu_info placement 1766 * optimizations because we don't use any pv_mmu or pv_irq op on 1767 * HVM. 1768 * When xen_hvm_init_shared_info is run at boot time only vcpu 0 is 1769 * online but xen_hvm_init_shared_info is run at resume time too and 1770 * in that case multiple vcpus might be online. */ 1771 for_each_online_cpu(cpu) { 1772 /* Leave it to be NULL. */ 1773 if (cpu >= MAX_VIRT_CPUS) 1774 continue; 1775 per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu]; 1776 } 1777 } 1778 1779 #ifdef CONFIG_XEN_PVHVM 1780 static void __init init_hvm_pv_info(void) 1781 { 1782 int major, minor; 1783 uint32_t eax, ebx, ecx, edx, pages, msr, base; 1784 u64 pfn; 1785 1786 base = xen_cpuid_base(); 1787 cpuid(base + 1, &eax, &ebx, &ecx, &edx); 1788 1789 major = eax >> 16; 1790 minor = eax & 0xffff; 1791 printk(KERN_INFO "Xen version %d.%d.\n", major, minor); 1792 1793 cpuid(base + 2, &pages, &msr, &ecx, &edx); 1794 1795 pfn = __pa(hypercall_page); 1796 wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32)); 1797 1798 xen_setup_features(); 1799 1800 pv_info.name = "Xen HVM"; 1801 1802 xen_domain_type = XEN_HVM_DOMAIN; 1803 } 1804 1805 static int xen_hvm_cpu_notify(struct notifier_block *self, unsigned long action, 1806 void *hcpu) 1807 { 1808 int cpu = (long)hcpu; 1809 switch (action) { 1810 case CPU_UP_PREPARE: 1811 xen_vcpu_setup(cpu); 1812 if (xen_have_vector_callback) { 1813 if (xen_feature(XENFEAT_hvm_safe_pvclock)) 1814 xen_setup_timer(cpu); 1815 } 1816 break; 1817 default: 1818 break; 1819 } 1820 return NOTIFY_OK; 1821 } 1822 1823 static struct notifier_block xen_hvm_cpu_notifier = { 1824 .notifier_call = xen_hvm_cpu_notify, 1825 }; 1826 1827 #ifdef CONFIG_KEXEC_CORE 1828 static void xen_hvm_shutdown(void) 1829 { 1830 native_machine_shutdown(); 1831 if (kexec_in_progress) 1832 xen_reboot(SHUTDOWN_soft_reset); 1833 } 1834 1835 static void xen_hvm_crash_shutdown(struct pt_regs *regs) 1836 { 1837 native_machine_crash_shutdown(regs); 1838 xen_reboot(SHUTDOWN_soft_reset); 1839 } 1840 #endif 1841 1842 static void __init xen_hvm_guest_init(void) 1843 { 1844 if (xen_pv_domain()) 1845 return; 1846 1847 init_hvm_pv_info(); 1848 1849 xen_hvm_init_shared_info(); 1850 1851 xen_panic_handler_init(); 1852 1853 if (xen_feature(XENFEAT_hvm_callback_vector)) 1854 xen_have_vector_callback = 1; 1855 xen_hvm_smp_init(); 1856 register_cpu_notifier(&xen_hvm_cpu_notifier); 1857 xen_unplug_emulated_devices(); 1858 x86_init.irqs.intr_init = xen_init_IRQ; 1859 xen_hvm_init_time_ops(); 1860 xen_hvm_init_mmu_ops(); 1861 #ifdef CONFIG_KEXEC_CORE 1862 machine_ops.shutdown = xen_hvm_shutdown; 1863 machine_ops.crash_shutdown = xen_hvm_crash_shutdown; 1864 #endif 1865 } 1866 #endif 1867 1868 static bool xen_nopv = false; 1869 static __init int xen_parse_nopv(char *arg) 1870 { 1871 xen_nopv = true; 1872 return 0; 1873 } 1874 early_param("xen_nopv", xen_parse_nopv); 1875 1876 static uint32_t __init xen_platform(void) 1877 { 1878 if (xen_nopv) 1879 return 0; 1880 1881 return xen_cpuid_base(); 1882 } 1883 1884 bool xen_hvm_need_lapic(void) 1885 { 1886 if (xen_nopv) 1887 return false; 1888 if (xen_pv_domain()) 1889 return false; 1890 if (!xen_hvm_domain()) 1891 return false; 1892 if (xen_feature(XENFEAT_hvm_pirqs) && xen_have_vector_callback) 1893 return false; 1894 return true; 1895 } 1896 EXPORT_SYMBOL_GPL(xen_hvm_need_lapic); 1897 1898 static void xen_set_cpu_features(struct cpuinfo_x86 *c) 1899 { 1900 if (xen_pv_domain()) { 1901 clear_cpu_bug(c, X86_BUG_SYSRET_SS_ATTRS); 1902 set_cpu_cap(c, X86_FEATURE_XENPV); 1903 } 1904 } 1905 1906 const struct hypervisor_x86 x86_hyper_xen = { 1907 .name = "Xen", 1908 .detect = xen_platform, 1909 #ifdef CONFIG_XEN_PVHVM 1910 .init_platform = xen_hvm_guest_init, 1911 #endif 1912 .x2apic_available = xen_x2apic_para_available, 1913 .set_cpu_features = xen_set_cpu_features, 1914 }; 1915 EXPORT_SYMBOL(x86_hyper_xen); 1916 1917 #ifdef CONFIG_HOTPLUG_CPU 1918 void xen_arch_register_cpu(int num) 1919 { 1920 arch_register_cpu(num); 1921 } 1922 EXPORT_SYMBOL(xen_arch_register_cpu); 1923 1924 void xen_arch_unregister_cpu(int num) 1925 { 1926 arch_unregister_cpu(num); 1927 } 1928 EXPORT_SYMBOL(xen_arch_unregister_cpu); 1929 #endif 1930