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) | 0 /* 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(AVX2) | F(SMEP) | F(BMI2) | F(ERMS); 251 252 /* all calls to cpuid_count() should be made on the same cpu */ 253 get_cpu(); 254 255 r = -E2BIG; 256 257 if (*nent >= maxnent) 258 goto out; 259 260 do_cpuid_1_ent(entry, function, index); 261 ++*nent; 262 263 switch (function) { 264 case 0: 265 entry->eax = min(entry->eax, (u32)0xd); 266 break; 267 case 1: 268 entry->edx &= kvm_supported_word0_x86_features; 269 cpuid_mask(&entry->edx, 0); 270 entry->ecx &= kvm_supported_word4_x86_features; 271 cpuid_mask(&entry->ecx, 4); 272 /* we support x2apic emulation even if host does not support 273 * it since we emulate x2apic in software */ 274 entry->ecx |= F(X2APIC); 275 break; 276 /* function 2 entries are STATEFUL. That is, repeated cpuid commands 277 * may return different values. This forces us to get_cpu() before 278 * issuing the first command, and also to emulate this annoying behavior 279 * in kvm_emulate_cpuid() using KVM_CPUID_FLAG_STATE_READ_NEXT */ 280 case 2: { 281 int t, times = entry->eax & 0xff; 282 283 entry->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC; 284 entry->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT; 285 for (t = 1; t < times; ++t) { 286 if (*nent >= maxnent) 287 goto out; 288 289 do_cpuid_1_ent(&entry[t], function, 0); 290 entry[t].flags |= KVM_CPUID_FLAG_STATEFUL_FUNC; 291 ++*nent; 292 } 293 break; 294 } 295 /* function 4 has additional index. */ 296 case 4: { 297 int i, cache_type; 298 299 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX; 300 /* read more entries until cache_type is zero */ 301 for (i = 1; ; ++i) { 302 if (*nent >= maxnent) 303 goto out; 304 305 cache_type = entry[i - 1].eax & 0x1f; 306 if (!cache_type) 307 break; 308 do_cpuid_1_ent(&entry[i], function, i); 309 entry[i].flags |= 310 KVM_CPUID_FLAG_SIGNIFCANT_INDEX; 311 ++*nent; 312 } 313 break; 314 } 315 case 7: { 316 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX; 317 /* Mask ebx against host capbability word 9 */ 318 if (index == 0) { 319 entry->ebx &= kvm_supported_word9_x86_features; 320 cpuid_mask(&entry->ebx, 9); 321 } else 322 entry->ebx = 0; 323 entry->eax = 0; 324 entry->ecx = 0; 325 entry->edx = 0; 326 break; 327 } 328 case 9: 329 break; 330 case 0xa: { /* Architectural Performance Monitoring */ 331 struct x86_pmu_capability cap; 332 union cpuid10_eax eax; 333 union cpuid10_edx edx; 334 335 perf_get_x86_pmu_capability(&cap); 336 337 /* 338 * Only support guest architectural pmu on a host 339 * with architectural pmu. 340 */ 341 if (!cap.version) 342 memset(&cap, 0, sizeof(cap)); 343 344 eax.split.version_id = min(cap.version, 2); 345 eax.split.num_counters = cap.num_counters_gp; 346 eax.split.bit_width = cap.bit_width_gp; 347 eax.split.mask_length = cap.events_mask_len; 348 349 edx.split.num_counters_fixed = cap.num_counters_fixed; 350 edx.split.bit_width_fixed = cap.bit_width_fixed; 351 edx.split.reserved = 0; 352 353 entry->eax = eax.full; 354 entry->ebx = cap.events_mask; 355 entry->ecx = 0; 356 entry->edx = edx.full; 357 break; 358 } 359 /* function 0xb has additional index. */ 360 case 0xb: { 361 int i, level_type; 362 363 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX; 364 /* read more entries until level_type is zero */ 365 for (i = 1; ; ++i) { 366 if (*nent >= maxnent) 367 goto out; 368 369 level_type = entry[i - 1].ecx & 0xff00; 370 if (!level_type) 371 break; 372 do_cpuid_1_ent(&entry[i], function, i); 373 entry[i].flags |= 374 KVM_CPUID_FLAG_SIGNIFCANT_INDEX; 375 ++*nent; 376 } 377 break; 378 } 379 case 0xd: { 380 int idx, i; 381 382 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX; 383 for (idx = 1, i = 1; idx < 64; ++idx) { 384 if (*nent >= maxnent) 385 goto out; 386 387 do_cpuid_1_ent(&entry[i], function, idx); 388 if (entry[i].eax == 0 || !supported_xcr0_bit(idx)) 389 continue; 390 entry[i].flags |= 391 KVM_CPUID_FLAG_SIGNIFCANT_INDEX; 392 ++*nent; 393 ++i; 394 } 395 break; 396 } 397 case KVM_CPUID_SIGNATURE: { 398 char signature[12] = "KVMKVMKVM\0\0"; 399 u32 *sigptr = (u32 *)signature; 400 entry->eax = 0; 401 entry->ebx = sigptr[0]; 402 entry->ecx = sigptr[1]; 403 entry->edx = sigptr[2]; 404 break; 405 } 406 case KVM_CPUID_FEATURES: 407 entry->eax = (1 << KVM_FEATURE_CLOCKSOURCE) | 408 (1 << KVM_FEATURE_NOP_IO_DELAY) | 409 (1 << KVM_FEATURE_CLOCKSOURCE2) | 410 (1 << KVM_FEATURE_ASYNC_PF) | 411 (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT); 412 413 if (sched_info_on()) 414 entry->eax |= (1 << KVM_FEATURE_STEAL_TIME); 415 416 entry->ebx = 0; 417 entry->ecx = 0; 418 entry->edx = 0; 419 break; 420 case 0x80000000: 421 entry->eax = min(entry->eax, 0x8000001a); 422 break; 423 case 0x80000001: 424 entry->edx &= kvm_supported_word1_x86_features; 425 cpuid_mask(&entry->edx, 1); 426 entry->ecx &= kvm_supported_word6_x86_features; 427 cpuid_mask(&entry->ecx, 6); 428 break; 429 case 0x80000008: { 430 unsigned g_phys_as = (entry->eax >> 16) & 0xff; 431 unsigned virt_as = max((entry->eax >> 8) & 0xff, 48U); 432 unsigned phys_as = entry->eax & 0xff; 433 434 if (!g_phys_as) 435 g_phys_as = phys_as; 436 entry->eax = g_phys_as | (virt_as << 8); 437 entry->ebx = entry->edx = 0; 438 break; 439 } 440 case 0x80000019: 441 entry->ecx = entry->edx = 0; 442 break; 443 case 0x8000001a: 444 break; 445 case 0x8000001d: 446 break; 447 /*Add support for Centaur's CPUID instruction*/ 448 case 0xC0000000: 449 /*Just support up to 0xC0000004 now*/ 450 entry->eax = min(entry->eax, 0xC0000004); 451 break; 452 case 0xC0000001: 453 entry->edx &= kvm_supported_word5_x86_features; 454 cpuid_mask(&entry->edx, 5); 455 break; 456 case 3: /* Processor serial number */ 457 case 5: /* MONITOR/MWAIT */ 458 case 6: /* Thermal management */ 459 case 0x80000007: /* Advanced power management */ 460 case 0xC0000002: 461 case 0xC0000003: 462 case 0xC0000004: 463 default: 464 entry->eax = entry->ebx = entry->ecx = entry->edx = 0; 465 break; 466 } 467 468 kvm_x86_ops->set_supported_cpuid(function, entry); 469 470 r = 0; 471 472 out: 473 put_cpu(); 474 475 return r; 476 } 477 478 #undef F 479 480 struct kvm_cpuid_param { 481 u32 func; 482 u32 idx; 483 bool has_leaf_count; 484 bool (*qualifier)(struct kvm_cpuid_param *param); 485 }; 486 487 static bool is_centaur_cpu(struct kvm_cpuid_param *param) 488 { 489 return boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR; 490 } 491 492 int kvm_dev_ioctl_get_supported_cpuid(struct kvm_cpuid2 *cpuid, 493 struct kvm_cpuid_entry2 __user *entries) 494 { 495 struct kvm_cpuid_entry2 *cpuid_entries; 496 int limit, nent = 0, r = -E2BIG, i; 497 u32 func; 498 static struct kvm_cpuid_param param[] = { 499 { .func = 0, .has_leaf_count = true }, 500 { .func = 0x80000000, .has_leaf_count = true }, 501 { .func = 0xC0000000, .qualifier = is_centaur_cpu, .has_leaf_count = true }, 502 { .func = KVM_CPUID_SIGNATURE }, 503 { .func = KVM_CPUID_FEATURES }, 504 }; 505 506 if (cpuid->nent < 1) 507 goto out; 508 if (cpuid->nent > KVM_MAX_CPUID_ENTRIES) 509 cpuid->nent = KVM_MAX_CPUID_ENTRIES; 510 r = -ENOMEM; 511 cpuid_entries = vmalloc(sizeof(struct kvm_cpuid_entry2) * cpuid->nent); 512 if (!cpuid_entries) 513 goto out; 514 515 r = 0; 516 for (i = 0; i < ARRAY_SIZE(param); i++) { 517 struct kvm_cpuid_param *ent = ¶m[i]; 518 519 if (ent->qualifier && !ent->qualifier(ent)) 520 continue; 521 522 r = do_cpuid_ent(&cpuid_entries[nent], ent->func, ent->idx, 523 &nent, cpuid->nent); 524 525 if (r) 526 goto out_free; 527 528 if (!ent->has_leaf_count) 529 continue; 530 531 limit = cpuid_entries[nent - 1].eax; 532 for (func = ent->func + 1; func <= limit && nent < cpuid->nent && r == 0; ++func) 533 r = do_cpuid_ent(&cpuid_entries[nent], func, ent->idx, 534 &nent, cpuid->nent); 535 536 if (r) 537 goto out_free; 538 } 539 540 r = -EFAULT; 541 if (copy_to_user(entries, cpuid_entries, 542 nent * sizeof(struct kvm_cpuid_entry2))) 543 goto out_free; 544 cpuid->nent = nent; 545 r = 0; 546 547 out_free: 548 vfree(cpuid_entries); 549 out: 550 return r; 551 } 552 553 static int move_to_next_stateful_cpuid_entry(struct kvm_vcpu *vcpu, int i) 554 { 555 struct kvm_cpuid_entry2 *e = &vcpu->arch.cpuid_entries[i]; 556 int j, nent = vcpu->arch.cpuid_nent; 557 558 e->flags &= ~KVM_CPUID_FLAG_STATE_READ_NEXT; 559 /* when no next entry is found, the current entry[i] is reselected */ 560 for (j = i + 1; ; j = (j + 1) % nent) { 561 struct kvm_cpuid_entry2 *ej = &vcpu->arch.cpuid_entries[j]; 562 if (ej->function == e->function) { 563 ej->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT; 564 return j; 565 } 566 } 567 return 0; /* silence gcc, even though control never reaches here */ 568 } 569 570 /* find an entry with matching function, matching index (if needed), and that 571 * should be read next (if it's stateful) */ 572 static int is_matching_cpuid_entry(struct kvm_cpuid_entry2 *e, 573 u32 function, u32 index) 574 { 575 if (e->function != function) 576 return 0; 577 if ((e->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX) && e->index != index) 578 return 0; 579 if ((e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC) && 580 !(e->flags & KVM_CPUID_FLAG_STATE_READ_NEXT)) 581 return 0; 582 return 1; 583 } 584 585 struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu, 586 u32 function, u32 index) 587 { 588 int i; 589 struct kvm_cpuid_entry2 *best = NULL; 590 591 for (i = 0; i < vcpu->arch.cpuid_nent; ++i) { 592 struct kvm_cpuid_entry2 *e; 593 594 e = &vcpu->arch.cpuid_entries[i]; 595 if (is_matching_cpuid_entry(e, function, index)) { 596 if (e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC) 597 move_to_next_stateful_cpuid_entry(vcpu, i); 598 best = e; 599 break; 600 } 601 } 602 return best; 603 } 604 EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry); 605 606 int cpuid_maxphyaddr(struct kvm_vcpu *vcpu) 607 { 608 struct kvm_cpuid_entry2 *best; 609 610 best = kvm_find_cpuid_entry(vcpu, 0x80000000, 0); 611 if (!best || best->eax < 0x80000008) 612 goto not_found; 613 best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0); 614 if (best) 615 return best->eax & 0xff; 616 not_found: 617 return 36; 618 } 619 620 /* 621 * If no match is found, check whether we exceed the vCPU's limit 622 * and return the content of the highest valid _standard_ leaf instead. 623 * This is to satisfy the CPUID specification. 624 */ 625 static struct kvm_cpuid_entry2* check_cpuid_limit(struct kvm_vcpu *vcpu, 626 u32 function, u32 index) 627 { 628 struct kvm_cpuid_entry2 *maxlevel; 629 630 maxlevel = kvm_find_cpuid_entry(vcpu, function & 0x80000000, 0); 631 if (!maxlevel || maxlevel->eax >= function) 632 return NULL; 633 if (function & 0x80000000) { 634 maxlevel = kvm_find_cpuid_entry(vcpu, 0, 0); 635 if (!maxlevel) 636 return NULL; 637 } 638 return kvm_find_cpuid_entry(vcpu, maxlevel->eax, index); 639 } 640 641 void kvm_emulate_cpuid(struct kvm_vcpu *vcpu) 642 { 643 u32 function, index; 644 struct kvm_cpuid_entry2 *best; 645 646 function = kvm_register_read(vcpu, VCPU_REGS_RAX); 647 index = kvm_register_read(vcpu, VCPU_REGS_RCX); 648 kvm_register_write(vcpu, VCPU_REGS_RAX, 0); 649 kvm_register_write(vcpu, VCPU_REGS_RBX, 0); 650 kvm_register_write(vcpu, VCPU_REGS_RCX, 0); 651 kvm_register_write(vcpu, VCPU_REGS_RDX, 0); 652 best = kvm_find_cpuid_entry(vcpu, function, index); 653 654 if (!best) 655 best = check_cpuid_limit(vcpu, function, index); 656 657 if (best) { 658 kvm_register_write(vcpu, VCPU_REGS_RAX, best->eax); 659 kvm_register_write(vcpu, VCPU_REGS_RBX, best->ebx); 660 kvm_register_write(vcpu, VCPU_REGS_RCX, best->ecx); 661 kvm_register_write(vcpu, VCPU_REGS_RDX, best->edx); 662 } 663 kvm_x86_ops->skip_emulated_instruction(vcpu); 664 trace_kvm_cpuid(function, 665 kvm_register_read(vcpu, VCPU_REGS_RAX), 666 kvm_register_read(vcpu, VCPU_REGS_RBX), 667 kvm_register_read(vcpu, VCPU_REGS_RCX), 668 kvm_register_read(vcpu, VCPU_REGS_RDX)); 669 } 670 EXPORT_SYMBOL_GPL(kvm_emulate_cpuid); 671