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