1 /* 2 * Kernel-based Virtual Machine driver for Linux 3 * cpuid support routines 4 * 5 * derived from arch/x86/kvm/x86.c 6 * 7 * Copyright 2011 Red Hat, Inc. and/or its affiliates. 8 * Copyright IBM Corporation, 2008 9 * 10 * This work is licensed under the terms of the GNU GPL, version 2. See 11 * the COPYING file in the top-level directory. 12 * 13 */ 14 15 #include <linux/kvm_host.h> 16 #include <linux/module.h> 17 #include <linux/vmalloc.h> 18 #include <linux/uaccess.h> 19 #include <asm/user.h> 20 #include <asm/xsave.h> 21 #include "cpuid.h" 22 #include "lapic.h" 23 #include "mmu.h" 24 #include "trace.h" 25 26 void kvm_update_cpuid(struct kvm_vcpu *vcpu) 27 { 28 struct kvm_cpuid_entry2 *best; 29 struct kvm_lapic *apic = vcpu->arch.apic; 30 31 best = kvm_find_cpuid_entry(vcpu, 1, 0); 32 if (!best) 33 return; 34 35 /* Update OSXSAVE bit */ 36 if (cpu_has_xsave && best->function == 0x1) { 37 best->ecx &= ~(bit(X86_FEATURE_OSXSAVE)); 38 if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE)) 39 best->ecx |= bit(X86_FEATURE_OSXSAVE); 40 } 41 42 if (apic) { 43 if (best->ecx & bit(X86_FEATURE_TSC_DEADLINE_TIMER)) 44 apic->lapic_timer.timer_mode_mask = 3 << 17; 45 else 46 apic->lapic_timer.timer_mode_mask = 1 << 17; 47 } 48 49 kvm_pmu_cpuid_update(vcpu); 50 } 51 52 static int is_efer_nx(void) 53 { 54 unsigned long long efer = 0; 55 56 rdmsrl_safe(MSR_EFER, &efer); 57 return efer & EFER_NX; 58 } 59 60 static void cpuid_fix_nx_cap(struct kvm_vcpu *vcpu) 61 { 62 int i; 63 struct kvm_cpuid_entry2 *e, *entry; 64 65 entry = NULL; 66 for (i = 0; i < vcpu->arch.cpuid_nent; ++i) { 67 e = &vcpu->arch.cpuid_entries[i]; 68 if (e->function == 0x80000001) { 69 entry = e; 70 break; 71 } 72 } 73 if (entry && (entry->edx & (1 << 20)) && !is_efer_nx()) { 74 entry->edx &= ~(1 << 20); 75 printk(KERN_INFO "kvm: guest NX capability removed\n"); 76 } 77 } 78 79 /* when an old userspace process fills a new kernel module */ 80 int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu, 81 struct kvm_cpuid *cpuid, 82 struct kvm_cpuid_entry __user *entries) 83 { 84 int r, i; 85 struct kvm_cpuid_entry *cpuid_entries; 86 87 r = -E2BIG; 88 if (cpuid->nent > KVM_MAX_CPUID_ENTRIES) 89 goto out; 90 r = -ENOMEM; 91 cpuid_entries = vmalloc(sizeof(struct kvm_cpuid_entry) * cpuid->nent); 92 if (!cpuid_entries) 93 goto out; 94 r = -EFAULT; 95 if (copy_from_user(cpuid_entries, entries, 96 cpuid->nent * sizeof(struct kvm_cpuid_entry))) 97 goto out_free; 98 for (i = 0; i < cpuid->nent; i++) { 99 vcpu->arch.cpuid_entries[i].function = cpuid_entries[i].function; 100 vcpu->arch.cpuid_entries[i].eax = cpuid_entries[i].eax; 101 vcpu->arch.cpuid_entries[i].ebx = cpuid_entries[i].ebx; 102 vcpu->arch.cpuid_entries[i].ecx = cpuid_entries[i].ecx; 103 vcpu->arch.cpuid_entries[i].edx = cpuid_entries[i].edx; 104 vcpu->arch.cpuid_entries[i].index = 0; 105 vcpu->arch.cpuid_entries[i].flags = 0; 106 vcpu->arch.cpuid_entries[i].padding[0] = 0; 107 vcpu->arch.cpuid_entries[i].padding[1] = 0; 108 vcpu->arch.cpuid_entries[i].padding[2] = 0; 109 } 110 vcpu->arch.cpuid_nent = cpuid->nent; 111 cpuid_fix_nx_cap(vcpu); 112 r = 0; 113 kvm_apic_set_version(vcpu); 114 kvm_x86_ops->cpuid_update(vcpu); 115 kvm_update_cpuid(vcpu); 116 117 out_free: 118 vfree(cpuid_entries); 119 out: 120 return r; 121 } 122 123 int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu, 124 struct kvm_cpuid2 *cpuid, 125 struct kvm_cpuid_entry2 __user *entries) 126 { 127 int r; 128 129 r = -E2BIG; 130 if (cpuid->nent > KVM_MAX_CPUID_ENTRIES) 131 goto out; 132 r = -EFAULT; 133 if (copy_from_user(&vcpu->arch.cpuid_entries, entries, 134 cpuid->nent * sizeof(struct kvm_cpuid_entry2))) 135 goto out; 136 vcpu->arch.cpuid_nent = cpuid->nent; 137 kvm_apic_set_version(vcpu); 138 kvm_x86_ops->cpuid_update(vcpu); 139 kvm_update_cpuid(vcpu); 140 return 0; 141 142 out: 143 return r; 144 } 145 146 int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu, 147 struct kvm_cpuid2 *cpuid, 148 struct kvm_cpuid_entry2 __user *entries) 149 { 150 int r; 151 152 r = -E2BIG; 153 if (cpuid->nent < vcpu->arch.cpuid_nent) 154 goto out; 155 r = -EFAULT; 156 if (copy_to_user(entries, &vcpu->arch.cpuid_entries, 157 vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2))) 158 goto out; 159 return 0; 160 161 out: 162 cpuid->nent = vcpu->arch.cpuid_nent; 163 return r; 164 } 165 166 static void cpuid_mask(u32 *word, int wordnum) 167 { 168 *word &= boot_cpu_data.x86_capability[wordnum]; 169 } 170 171 static void do_cpuid_1_ent(struct kvm_cpuid_entry2 *entry, u32 function, 172 u32 index) 173 { 174 entry->function = function; 175 entry->index = index; 176 cpuid_count(entry->function, entry->index, 177 &entry->eax, &entry->ebx, &entry->ecx, &entry->edx); 178 entry->flags = 0; 179 } 180 181 static bool supported_xcr0_bit(unsigned bit) 182 { 183 u64 mask = ((u64)1 << bit); 184 185 return mask & (XSTATE_FP | XSTATE_SSE | XSTATE_YMM) & host_xcr0; 186 } 187 188 #define F(x) bit(X86_FEATURE_##x) 189 190 static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, 191 u32 index, int *nent, int maxnent) 192 { 193 int r; 194 unsigned f_nx = is_efer_nx() ? F(NX) : 0; 195 #ifdef CONFIG_X86_64 196 unsigned f_gbpages = (kvm_x86_ops->get_lpage_level() == PT_PDPE_LEVEL) 197 ? F(GBPAGES) : 0; 198 unsigned f_lm = F(LM); 199 #else 200 unsigned f_gbpages = 0; 201 unsigned f_lm = 0; 202 #endif 203 unsigned f_rdtscp = kvm_x86_ops->rdtscp_supported() ? F(RDTSCP) : 0; 204 205 /* cpuid 1.edx */ 206 const u32 kvm_supported_word0_x86_features = 207 F(FPU) | F(VME) | F(DE) | F(PSE) | 208 F(TSC) | F(MSR) | F(PAE) | F(MCE) | 209 F(CX8) | F(APIC) | 0 /* Reserved */ | F(SEP) | 210 F(MTRR) | F(PGE) | F(MCA) | F(CMOV) | 211 F(PAT) | F(PSE36) | 0 /* PSN */ | F(CLFLSH) | 212 0 /* Reserved, DS, ACPI */ | F(MMX) | 213 F(FXSR) | F(XMM) | F(XMM2) | F(SELFSNOOP) | 214 0 /* HTT, TM, Reserved, PBE */; 215 /* cpuid 0x80000001.edx */ 216 const u32 kvm_supported_word1_x86_features = 217 F(FPU) | F(VME) | F(DE) | F(PSE) | 218 F(TSC) | F(MSR) | F(PAE) | F(MCE) | 219 F(CX8) | F(APIC) | 0 /* Reserved */ | F(SYSCALL) | 220 F(MTRR) | F(PGE) | F(MCA) | F(CMOV) | 221 F(PAT) | F(PSE36) | 0 /* Reserved */ | 222 f_nx | 0 /* Reserved */ | F(MMXEXT) | F(MMX) | 223 F(FXSR) | F(FXSR_OPT) | f_gbpages | f_rdtscp | 224 0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW); 225 /* cpuid 1.ecx */ 226 const u32 kvm_supported_word4_x86_features = 227 F(XMM3) | F(PCLMULQDQ) | 0 /* DTES64, MONITOR */ | 228 0 /* DS-CPL, VMX, SMX, EST */ | 229 0 /* TM2 */ | F(SSSE3) | 0 /* CNXT-ID */ | 0 /* Reserved */ | 230 F(FMA) | F(CX16) | 0 /* xTPR Update, PDCM */ | 231 0 /* Reserved, DCA */ | F(XMM4_1) | 232 F(XMM4_2) | F(X2APIC) | F(MOVBE) | F(POPCNT) | 233 0 /* Reserved*/ | F(AES) | F(XSAVE) | 0 /* OSXSAVE */ | F(AVX) | 234 F(F16C) | F(RDRAND); 235 /* cpuid 0x80000001.ecx */ 236 const u32 kvm_supported_word6_x86_features = 237 F(LAHF_LM) | F(CMP_LEGACY) | 0 /*SVM*/ | 0 /* ExtApicSpace */ | 238 F(CR8_LEGACY) | F(ABM) | F(SSE4A) | F(MISALIGNSSE) | 239 F(3DNOWPREFETCH) | F(OSVW) | 0 /* IBS */ | F(XOP) | 240 0 /* SKINIT, WDT, LWP */ | F(FMA4) | F(TBM); 241 242 /* cpuid 0xC0000001.edx */ 243 const u32 kvm_supported_word5_x86_features = 244 F(XSTORE) | F(XSTORE_EN) | F(XCRYPT) | F(XCRYPT_EN) | 245 F(ACE2) | F(ACE2_EN) | F(PHE) | F(PHE_EN) | 246 F(PMM) | F(PMM_EN); 247 248 /* cpuid 7.0.ebx */ 249 const u32 kvm_supported_word9_x86_features = 250 F(FSGSBASE) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) | 251 F(BMI2) | F(ERMS) | F(RTM); 252 253 /* all calls to cpuid_count() should be made on the same cpu */ 254 get_cpu(); 255 256 r = -E2BIG; 257 258 if (*nent >= maxnent) 259 goto out; 260 261 do_cpuid_1_ent(entry, function, index); 262 ++*nent; 263 264 switch (function) { 265 case 0: 266 entry->eax = min(entry->eax, (u32)0xd); 267 break; 268 case 1: 269 entry->edx &= kvm_supported_word0_x86_features; 270 cpuid_mask(&entry->edx, 0); 271 entry->ecx &= kvm_supported_word4_x86_features; 272 cpuid_mask(&entry->ecx, 4); 273 /* we support x2apic emulation even if host does not support 274 * it since we emulate x2apic in software */ 275 entry->ecx |= F(X2APIC); 276 break; 277 /* function 2 entries are STATEFUL. That is, repeated cpuid commands 278 * may return different values. This forces us to get_cpu() before 279 * issuing the first command, and also to emulate this annoying behavior 280 * in kvm_emulate_cpuid() using KVM_CPUID_FLAG_STATE_READ_NEXT */ 281 case 2: { 282 int t, times = entry->eax & 0xff; 283 284 entry->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC; 285 entry->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT; 286 for (t = 1; t < times; ++t) { 287 if (*nent >= maxnent) 288 goto out; 289 290 do_cpuid_1_ent(&entry[t], function, 0); 291 entry[t].flags |= KVM_CPUID_FLAG_STATEFUL_FUNC; 292 ++*nent; 293 } 294 break; 295 } 296 /* function 4 has additional index. */ 297 case 4: { 298 int i, cache_type; 299 300 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX; 301 /* read more entries until cache_type is zero */ 302 for (i = 1; ; ++i) { 303 if (*nent >= maxnent) 304 goto out; 305 306 cache_type = entry[i - 1].eax & 0x1f; 307 if (!cache_type) 308 break; 309 do_cpuid_1_ent(&entry[i], function, i); 310 entry[i].flags |= 311 KVM_CPUID_FLAG_SIGNIFCANT_INDEX; 312 ++*nent; 313 } 314 break; 315 } 316 case 7: { 317 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX; 318 /* Mask ebx against host capbability word 9 */ 319 if (index == 0) { 320 entry->ebx &= kvm_supported_word9_x86_features; 321 cpuid_mask(&entry->ebx, 9); 322 } else 323 entry->ebx = 0; 324 entry->eax = 0; 325 entry->ecx = 0; 326 entry->edx = 0; 327 break; 328 } 329 case 9: 330 break; 331 case 0xa: { /* Architectural Performance Monitoring */ 332 struct x86_pmu_capability cap; 333 union cpuid10_eax eax; 334 union cpuid10_edx edx; 335 336 perf_get_x86_pmu_capability(&cap); 337 338 /* 339 * Only support guest architectural pmu on a host 340 * with architectural pmu. 341 */ 342 if (!cap.version) 343 memset(&cap, 0, sizeof(cap)); 344 345 eax.split.version_id = min(cap.version, 2); 346 eax.split.num_counters = cap.num_counters_gp; 347 eax.split.bit_width = cap.bit_width_gp; 348 eax.split.mask_length = cap.events_mask_len; 349 350 edx.split.num_counters_fixed = cap.num_counters_fixed; 351 edx.split.bit_width_fixed = cap.bit_width_fixed; 352 edx.split.reserved = 0; 353 354 entry->eax = eax.full; 355 entry->ebx = cap.events_mask; 356 entry->ecx = 0; 357 entry->edx = edx.full; 358 break; 359 } 360 /* function 0xb has additional index. */ 361 case 0xb: { 362 int i, level_type; 363 364 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX; 365 /* read more entries until level_type is zero */ 366 for (i = 1; ; ++i) { 367 if (*nent >= maxnent) 368 goto out; 369 370 level_type = entry[i - 1].ecx & 0xff00; 371 if (!level_type) 372 break; 373 do_cpuid_1_ent(&entry[i], function, i); 374 entry[i].flags |= 375 KVM_CPUID_FLAG_SIGNIFCANT_INDEX; 376 ++*nent; 377 } 378 break; 379 } 380 case 0xd: { 381 int idx, i; 382 383 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX; 384 for (idx = 1, i = 1; idx < 64; ++idx) { 385 if (*nent >= maxnent) 386 goto out; 387 388 do_cpuid_1_ent(&entry[i], function, idx); 389 if (entry[i].eax == 0 || !supported_xcr0_bit(idx)) 390 continue; 391 entry[i].flags |= 392 KVM_CPUID_FLAG_SIGNIFCANT_INDEX; 393 ++*nent; 394 ++i; 395 } 396 break; 397 } 398 case KVM_CPUID_SIGNATURE: { 399 char signature[12] = "KVMKVMKVM\0\0"; 400 u32 *sigptr = (u32 *)signature; 401 entry->eax = KVM_CPUID_FEATURES; 402 entry->ebx = sigptr[0]; 403 entry->ecx = sigptr[1]; 404 entry->edx = sigptr[2]; 405 break; 406 } 407 case KVM_CPUID_FEATURES: 408 entry->eax = (1 << KVM_FEATURE_CLOCKSOURCE) | 409 (1 << KVM_FEATURE_NOP_IO_DELAY) | 410 (1 << KVM_FEATURE_CLOCKSOURCE2) | 411 (1 << KVM_FEATURE_ASYNC_PF) | 412 (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT); 413 414 if (sched_info_on()) 415 entry->eax |= (1 << KVM_FEATURE_STEAL_TIME); 416 417 entry->ebx = 0; 418 entry->ecx = 0; 419 entry->edx = 0; 420 break; 421 case 0x80000000: 422 entry->eax = min(entry->eax, 0x8000001a); 423 break; 424 case 0x80000001: 425 entry->edx &= kvm_supported_word1_x86_features; 426 cpuid_mask(&entry->edx, 1); 427 entry->ecx &= kvm_supported_word6_x86_features; 428 cpuid_mask(&entry->ecx, 6); 429 break; 430 case 0x80000008: { 431 unsigned g_phys_as = (entry->eax >> 16) & 0xff; 432 unsigned virt_as = max((entry->eax >> 8) & 0xff, 48U); 433 unsigned phys_as = entry->eax & 0xff; 434 435 if (!g_phys_as) 436 g_phys_as = phys_as; 437 entry->eax = g_phys_as | (virt_as << 8); 438 entry->ebx = entry->edx = 0; 439 break; 440 } 441 case 0x80000019: 442 entry->ecx = entry->edx = 0; 443 break; 444 case 0x8000001a: 445 break; 446 case 0x8000001d: 447 break; 448 /*Add support for Centaur's CPUID instruction*/ 449 case 0xC0000000: 450 /*Just support up to 0xC0000004 now*/ 451 entry->eax = min(entry->eax, 0xC0000004); 452 break; 453 case 0xC0000001: 454 entry->edx &= kvm_supported_word5_x86_features; 455 cpuid_mask(&entry->edx, 5); 456 break; 457 case 3: /* Processor serial number */ 458 case 5: /* MONITOR/MWAIT */ 459 case 6: /* Thermal management */ 460 case 0x80000007: /* Advanced power management */ 461 case 0xC0000002: 462 case 0xC0000003: 463 case 0xC0000004: 464 default: 465 entry->eax = entry->ebx = entry->ecx = entry->edx = 0; 466 break; 467 } 468 469 kvm_x86_ops->set_supported_cpuid(function, entry); 470 471 r = 0; 472 473 out: 474 put_cpu(); 475 476 return r; 477 } 478 479 #undef F 480 481 struct kvm_cpuid_param { 482 u32 func; 483 u32 idx; 484 bool has_leaf_count; 485 bool (*qualifier)(struct kvm_cpuid_param *param); 486 }; 487 488 static bool is_centaur_cpu(struct kvm_cpuid_param *param) 489 { 490 return boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR; 491 } 492 493 int kvm_dev_ioctl_get_supported_cpuid(struct kvm_cpuid2 *cpuid, 494 struct kvm_cpuid_entry2 __user *entries) 495 { 496 struct kvm_cpuid_entry2 *cpuid_entries; 497 int limit, nent = 0, r = -E2BIG, i; 498 u32 func; 499 static struct kvm_cpuid_param param[] = { 500 { .func = 0, .has_leaf_count = true }, 501 { .func = 0x80000000, .has_leaf_count = true }, 502 { .func = 0xC0000000, .qualifier = is_centaur_cpu, .has_leaf_count = true }, 503 { .func = KVM_CPUID_SIGNATURE }, 504 { .func = KVM_CPUID_FEATURES }, 505 }; 506 507 if (cpuid->nent < 1) 508 goto out; 509 if (cpuid->nent > KVM_MAX_CPUID_ENTRIES) 510 cpuid->nent = KVM_MAX_CPUID_ENTRIES; 511 r = -ENOMEM; 512 cpuid_entries = vmalloc(sizeof(struct kvm_cpuid_entry2) * cpuid->nent); 513 if (!cpuid_entries) 514 goto out; 515 516 r = 0; 517 for (i = 0; i < ARRAY_SIZE(param); i++) { 518 struct kvm_cpuid_param *ent = ¶m[i]; 519 520 if (ent->qualifier && !ent->qualifier(ent)) 521 continue; 522 523 r = do_cpuid_ent(&cpuid_entries[nent], ent->func, ent->idx, 524 &nent, cpuid->nent); 525 526 if (r) 527 goto out_free; 528 529 if (!ent->has_leaf_count) 530 continue; 531 532 limit = cpuid_entries[nent - 1].eax; 533 for (func = ent->func + 1; func <= limit && nent < cpuid->nent && r == 0; ++func) 534 r = do_cpuid_ent(&cpuid_entries[nent], func, ent->idx, 535 &nent, cpuid->nent); 536 537 if (r) 538 goto out_free; 539 } 540 541 r = -EFAULT; 542 if (copy_to_user(entries, cpuid_entries, 543 nent * sizeof(struct kvm_cpuid_entry2))) 544 goto out_free; 545 cpuid->nent = nent; 546 r = 0; 547 548 out_free: 549 vfree(cpuid_entries); 550 out: 551 return r; 552 } 553 554 static int move_to_next_stateful_cpuid_entry(struct kvm_vcpu *vcpu, int i) 555 { 556 struct kvm_cpuid_entry2 *e = &vcpu->arch.cpuid_entries[i]; 557 int j, nent = vcpu->arch.cpuid_nent; 558 559 e->flags &= ~KVM_CPUID_FLAG_STATE_READ_NEXT; 560 /* when no next entry is found, the current entry[i] is reselected */ 561 for (j = i + 1; ; j = (j + 1) % nent) { 562 struct kvm_cpuid_entry2 *ej = &vcpu->arch.cpuid_entries[j]; 563 if (ej->function == e->function) { 564 ej->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT; 565 return j; 566 } 567 } 568 return 0; /* silence gcc, even though control never reaches here */ 569 } 570 571 /* find an entry with matching function, matching index (if needed), and that 572 * should be read next (if it's stateful) */ 573 static int is_matching_cpuid_entry(struct kvm_cpuid_entry2 *e, 574 u32 function, u32 index) 575 { 576 if (e->function != function) 577 return 0; 578 if ((e->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX) && e->index != index) 579 return 0; 580 if ((e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC) && 581 !(e->flags & KVM_CPUID_FLAG_STATE_READ_NEXT)) 582 return 0; 583 return 1; 584 } 585 586 struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu, 587 u32 function, u32 index) 588 { 589 int i; 590 struct kvm_cpuid_entry2 *best = NULL; 591 592 for (i = 0; i < vcpu->arch.cpuid_nent; ++i) { 593 struct kvm_cpuid_entry2 *e; 594 595 e = &vcpu->arch.cpuid_entries[i]; 596 if (is_matching_cpuid_entry(e, function, index)) { 597 if (e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC) 598 move_to_next_stateful_cpuid_entry(vcpu, i); 599 best = e; 600 break; 601 } 602 } 603 return best; 604 } 605 EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry); 606 607 int cpuid_maxphyaddr(struct kvm_vcpu *vcpu) 608 { 609 struct kvm_cpuid_entry2 *best; 610 611 best = kvm_find_cpuid_entry(vcpu, 0x80000000, 0); 612 if (!best || best->eax < 0x80000008) 613 goto not_found; 614 best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0); 615 if (best) 616 return best->eax & 0xff; 617 not_found: 618 return 36; 619 } 620 621 /* 622 * If no match is found, check whether we exceed the vCPU's limit 623 * and return the content of the highest valid _standard_ leaf instead. 624 * This is to satisfy the CPUID specification. 625 */ 626 static struct kvm_cpuid_entry2* check_cpuid_limit(struct kvm_vcpu *vcpu, 627 u32 function, u32 index) 628 { 629 struct kvm_cpuid_entry2 *maxlevel; 630 631 maxlevel = kvm_find_cpuid_entry(vcpu, function & 0x80000000, 0); 632 if (!maxlevel || maxlevel->eax >= function) 633 return NULL; 634 if (function & 0x80000000) { 635 maxlevel = kvm_find_cpuid_entry(vcpu, 0, 0); 636 if (!maxlevel) 637 return NULL; 638 } 639 return kvm_find_cpuid_entry(vcpu, maxlevel->eax, index); 640 } 641 642 void kvm_emulate_cpuid(struct kvm_vcpu *vcpu) 643 { 644 u32 function, index; 645 struct kvm_cpuid_entry2 *best; 646 647 function = kvm_register_read(vcpu, VCPU_REGS_RAX); 648 index = kvm_register_read(vcpu, VCPU_REGS_RCX); 649 kvm_register_write(vcpu, VCPU_REGS_RAX, 0); 650 kvm_register_write(vcpu, VCPU_REGS_RBX, 0); 651 kvm_register_write(vcpu, VCPU_REGS_RCX, 0); 652 kvm_register_write(vcpu, VCPU_REGS_RDX, 0); 653 best = kvm_find_cpuid_entry(vcpu, function, index); 654 655 if (!best) 656 best = check_cpuid_limit(vcpu, function, index); 657 658 if (best) { 659 kvm_register_write(vcpu, VCPU_REGS_RAX, best->eax); 660 kvm_register_write(vcpu, VCPU_REGS_RBX, best->ebx); 661 kvm_register_write(vcpu, VCPU_REGS_RCX, best->ecx); 662 kvm_register_write(vcpu, VCPU_REGS_RDX, best->edx); 663 } 664 kvm_x86_ops->skip_emulated_instruction(vcpu); 665 trace_kvm_cpuid(function, 666 kvm_register_read(vcpu, VCPU_REGS_RAX), 667 kvm_register_read(vcpu, VCPU_REGS_RBX), 668 kvm_register_read(vcpu, VCPU_REGS_RCX), 669 kvm_register_read(vcpu, VCPU_REGS_RDX)); 670 } 671 EXPORT_SYMBOL_GPL(kvm_emulate_cpuid); 672