arch/x86/kvm/cpuid.c

   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/fpu/internal.h> /* For use_eager_fpu.  Ugh! */
  20 #include <asm/user.h>
  21 #include <asm/fpu/xstate.h>
  22 #include "cpuid.h"
  23 #include "lapic.h"
  24 #include "mmu.h"
  25 #include "trace.h"
  26 #include "pmu.h"
  27
  28 static u32 xstate_required_size(u64 xstate_bv, bool compacted)
  29 {
  30         int feature_bit = 0;
  31         u32 ret = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
  32
  33         xstate_bv &= XSTATE_EXTEND_MASK;
  34         while (xstate_bv) {
  35                 if (xstate_bv & 0x1) {
  36                         u32 eax, ebx, ecx, edx, offset;
  37                         cpuid_count(0xD, feature_bit, &eax, &ebx, &ecx, &edx);
  38                         offset = compacted ? ret : ebx;
  39                         ret = max(ret, offset + eax);
  40                 }
  41
  42                 xstate_bv >>= 1;
  43                 feature_bit++;
  44         }
  45
  46         return ret;
  47 }
  48
  49 u64 kvm_supported_xcr0(void)
  50 {
  51         u64 xcr0 = KVM_SUPPORTED_XCR0 & host_xcr0;
  52
  53         if (!kvm_x86_ops->mpx_supported())
  54                 xcr0 &= ~(XSTATE_BNDREGS | XSTATE_BNDCSR);
  55
  56         return xcr0;
  57 }
  58
  59 #define F(x) bit(X86_FEATURE_##x)
  60
  61 int kvm_update_cpuid(struct kvm_vcpu *vcpu)
  62 {
  63         struct kvm_cpuid_entry2 *best;
  64         struct kvm_lapic *apic = vcpu->arch.apic;
  65
  66         best = kvm_find_cpuid_entry(vcpu, 1, 0);
  67         if (!best)
  68                 return 0;
  69
  70         /* Update OSXSAVE bit */
  71         if (cpu_has_xsave && best->function == 0x1) {
  72                 best->ecx &= ~F(OSXSAVE);
  73                 if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE))
  74                         best->ecx |= F(OSXSAVE);
  75         }
  76
  77         if (apic) {
  78                 if (best->ecx & F(TSC_DEADLINE_TIMER))
  79                         apic->lapic_timer.timer_mode_mask = 3 << 17;
  80                 else
  81                         apic->lapic_timer.timer_mode_mask = 1 << 17;
  82         }
  83
  84         best = kvm_find_cpuid_entry(vcpu, 0xD, 0);
  85         if (!best) {
  86                 vcpu->arch.guest_supported_xcr0 = 0;
  87                 vcpu->arch.guest_xstate_size = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
  88         } else {
  89                 vcpu->arch.guest_supported_xcr0 =
  90                         (best->eax | ((u64)best->edx << 32)) &
  91                         kvm_supported_xcr0();
  92                 vcpu->arch.guest_xstate_size = best->ebx =
  93                         xstate_required_size(vcpu->arch.xcr0, false);
  94         }
  95
  96         best = kvm_find_cpuid_entry(vcpu, 0xD, 1);
  97         if (best && (best->eax & (F(XSAVES) | F(XSAVEC))))
  98                 best->ebx = xstate_required_size(vcpu->arch.xcr0, true);
  99
 100         vcpu->arch.eager_fpu = use_eager_fpu() || guest_cpuid_has_mpx(vcpu);
 101         if (vcpu->arch.eager_fpu)
 102                 kvm_x86_ops->fpu_activate(vcpu);
 103
 104         /*
 105          * The existing code assumes virtual address is 48-bit in the canonical
 106          * address checks; exit if it is ever changed.
 107          */
 108         best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
 109         if (best && ((best->eax & 0xff00) >> 8) != 48 &&
 110                 ((best->eax & 0xff00) >> 8) != 0)
 111                 return -EINVAL;
 112
 113         /* Update physical-address width */
 114         vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
 115
 116         kvm_pmu_refresh(vcpu);
 117         return 0;
 118 }
 119
 120 static int is_efer_nx(void)
 121 {
 122         unsigned long long efer = 0;
 123
 124         rdmsrl_safe(MSR_EFER, &efer);
 125         return efer & EFER_NX;
 126 }
 127
 128 static void cpuid_fix_nx_cap(struct kvm_vcpu *vcpu)
 129 {
 130         int i;
 131         struct kvm_cpuid_entry2 *e, *entry;
 132
 133         entry = NULL;
 134         for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
 135                 e = &vcpu->arch.cpuid_entries[i];
 136                 if (e->function == 0x80000001) {
 137                         entry = e;
 138                         break;
 139                 }
 140         }
 141         if (entry && (entry->edx & F(NX)) && !is_efer_nx()) {
 142                 entry->edx &= ~F(NX);
 143                 printk(KERN_INFO "kvm: guest NX capability removed\n");
 144         }
 145 }
 146
 147 int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu)
 148 {
 149         struct kvm_cpuid_entry2 *best;
 150
 151         best = kvm_find_cpuid_entry(vcpu, 0x80000000, 0);
 152         if (!best || best->eax < 0x80000008)
 153                 goto not_found;
 154         best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
 155         if (best)
 156                 return best->eax & 0xff;
 157 not_found:
 158         return 36;
 159 }
 160 EXPORT_SYMBOL_GPL(cpuid_query_maxphyaddr);
 161
 162 /* when an old userspace process fills a new kernel module */
 163 int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
 164                              struct kvm_cpuid *cpuid,
 165                              struct kvm_cpuid_entry __user *entries)
 166 {
 167         int r, i;
 168         struct kvm_cpuid_entry *cpuid_entries;
 169
 170         r = -E2BIG;
 171         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
 172                 goto out;
 173         r = -ENOMEM;
 174         cpuid_entries = vmalloc(sizeof(struct kvm_cpuid_entry) * cpuid->nent);
 175         if (!cpuid_entries)
 176                 goto out;
 177         r = -EFAULT;
 178         if (copy_from_user(cpuid_entries, entries,
 179                            cpuid->nent * sizeof(struct kvm_cpuid_entry)))
 180                 goto out_free;
 181         for (i = 0; i < cpuid->nent; i++) {
 182                 vcpu->arch.cpuid_entries[i].function = cpuid_entries[i].function;
 183                 vcpu->arch.cpuid_entries[i].eax = cpuid_entries[i].eax;
 184                 vcpu->arch.cpuid_entries[i].ebx = cpuid_entries[i].ebx;
 185                 vcpu->arch.cpuid_entries[i].ecx = cpuid_entries[i].ecx;
 186                 vcpu->arch.cpuid_entries[i].edx = cpuid_entries[i].edx;
 187                 vcpu->arch.cpuid_entries[i].index = 0;
 188                 vcpu->arch.cpuid_entries[i].flags = 0;
 189                 vcpu->arch.cpuid_entries[i].padding[0] = 0;
 190                 vcpu->arch.cpuid_entries[i].padding[1] = 0;
 191                 vcpu->arch.cpuid_entries[i].padding[2] = 0;
 192         }
 193         vcpu->arch.cpuid_nent = cpuid->nent;
 194         cpuid_fix_nx_cap(vcpu);
 195         kvm_apic_set_version(vcpu);
 196         kvm_x86_ops->cpuid_update(vcpu);
 197         r = kvm_update_cpuid(vcpu);
 198
 199 out_free:
 200         vfree(cpuid_entries);
 201 out:
 202         return r;
 203 }
 204
 205 int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
 206                               struct kvm_cpuid2 *cpuid,
 207                               struct kvm_cpuid_entry2 __user *entries)
 208 {
 209         int r;
 210
 211         r = -E2BIG;
 212         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
 213                 goto out;
 214         r = -EFAULT;
 215         if (copy_from_user(&vcpu->arch.cpuid_entries, entries,
 216                            cpuid->nent * sizeof(struct kvm_cpuid_entry2)))
 217                 goto out;
 218         vcpu->arch.cpuid_nent = cpuid->nent;
 219         kvm_apic_set_version(vcpu);
 220         kvm_x86_ops->cpuid_update(vcpu);
 221         r = kvm_update_cpuid(vcpu);
 222 out:
 223         return r;
 224 }
 225
 226 int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
 227                               struct kvm_cpuid2 *cpuid,
 228                               struct kvm_cpuid_entry2 __user *entries)
 229 {
 230         int r;
 231
 232         r = -E2BIG;
 233         if (cpuid->nent < vcpu->arch.cpuid_nent)
 234                 goto out;
 235         r = -EFAULT;
 236         if (copy_to_user(entries, &vcpu->arch.cpuid_entries,
 237                          vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2)))
 238                 goto out;
 239         return 0;
 240
 241 out:
 242         cpuid->nent = vcpu->arch.cpuid_nent;
 243         return r;
 244 }
 245
 246 static void cpuid_mask(u32 *word, int wordnum)
 247 {
 248         *word &= boot_cpu_data.x86_capability[wordnum];
 249 }
 250
 251 static void do_cpuid_1_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 252                            u32 index)
 253 {
 254         entry->function = function;
 255         entry->index = index;
 256         cpuid_count(entry->function, entry->index,
 257                     &entry->eax, &entry->ebx, &entry->ecx, &entry->edx);
 258         entry->flags = 0;
 259 }
 260
 261 static int __do_cpuid_ent_emulated(struct kvm_cpuid_entry2 *entry,
 262                                    u32 func, u32 index, int *nent, int maxnent)
 263 {
 264         switch (func) {
 265         case 0:
 266                 entry->eax = 1;         /* only one leaf currently */
 267                 ++*nent;
 268                 break;
 269         case 1:
 270                 entry->ecx = F(MOVBE);
 271                 ++*nent;
 272                 break;
 273         default:
 274                 break;
 275         }
 276
 277         entry->function = func;
 278         entry->index = index;
 279
 280         return 0;
 281 }
 282
 283 static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 284                                  u32 index, int *nent, int maxnent)
 285 {
 286         int r;
 287         unsigned f_nx = is_efer_nx() ? F(NX) : 0;
 288 #ifdef CONFIG_X86_64
 289         unsigned f_gbpages = (kvm_x86_ops->get_lpage_level() == PT_PDPE_LEVEL)
 290                                 ? F(GBPAGES) : 0;
 291         unsigned f_lm = F(LM);
 292 #else
 293         unsigned f_gbpages = 0;
 294         unsigned f_lm = 0;
 295 #endif
 296         unsigned f_rdtscp = kvm_x86_ops->rdtscp_supported() ? F(RDTSCP) : 0;
 297         unsigned f_invpcid = kvm_x86_ops->invpcid_supported() ? F(INVPCID) : 0;
 298         unsigned f_mpx = kvm_x86_ops->mpx_supported() ? F(MPX) : 0;
 299         unsigned f_xsaves = kvm_x86_ops->xsaves_supported() ? F(XSAVES) : 0;
 300
 301         /* cpuid 1.edx */
 302         const u32 kvm_supported_word0_x86_features =
 303                 F(FPU) | F(VME) | F(DE) | F(PSE) |
 304                 F(TSC) | F(MSR) | F(PAE) | F(MCE) |
 305                 F(CX8) | F(APIC) | 0 /* Reserved */ | F(SEP) |
 306                 F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
 307                 F(PAT) | F(PSE36) | 0 /* PSN */ | F(CLFLUSH) |
 308                 0 /* Reserved, DS, ACPI */ | F(MMX) |
 309                 F(FXSR) | F(XMM) | F(XMM2) | F(SELFSNOOP) |
 310                 0 /* HTT, TM, Reserved, PBE */;
 311         /* cpuid 0x80000001.edx */
 312         const u32 kvm_supported_word1_x86_features =
 313                 F(FPU) | F(VME) | F(DE) | F(PSE) |
 314                 F(TSC) | F(MSR) | F(PAE) | F(MCE) |
 315                 F(CX8) | F(APIC) | 0 /* Reserved */ | F(SYSCALL) |
 316                 F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
 317                 F(PAT) | F(PSE36) | 0 /* Reserved */ |
 318                 f_nx | 0 /* Reserved */ | F(MMXEXT) | F(MMX) |
 319                 F(FXSR) | F(FXSR_OPT) | f_gbpages | f_rdtscp |
 320                 0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW);
 321         /* cpuid 1.ecx */
 322         const u32 kvm_supported_word4_x86_features =
 323                 /* NOTE: MONITOR (and MWAIT) are emulated as NOP,
 324                  * but *not* advertised to guests via CPUID ! */
 325                 F(XMM3) | F(PCLMULQDQ) | 0 /* DTES64, MONITOR */ |
 326                 0 /* DS-CPL, VMX, SMX, EST */ |
 327                 0 /* TM2 */ | F(SSSE3) | 0 /* CNXT-ID */ | 0 /* Reserved */ |
 328                 F(FMA) | F(CX16) | 0 /* xTPR Update, PDCM */ |
 329                 F(PCID) | 0 /* Reserved, DCA */ | F(XMM4_1) |
 330                 F(XMM4_2) | F(X2APIC) | F(MOVBE) | F(POPCNT) |
 331                 0 /* Reserved*/ | F(AES) | F(XSAVE) | 0 /* OSXSAVE */ | F(AVX) |
 332                 F(F16C) | F(RDRAND);
 333         /* cpuid 0x80000001.ecx */
 334         const u32 kvm_supported_word6_x86_features =
 335                 F(LAHF_LM) | F(CMP_LEGACY) | 0 /*SVM*/ | 0 /* ExtApicSpace */ |
 336                 F(CR8_LEGACY) | F(ABM) | F(SSE4A) | F(MISALIGNSSE) |
 337                 F(3DNOWPREFETCH) | F(OSVW) | 0 /* IBS */ | F(XOP) |
 338                 0 /* SKINIT, WDT, LWP */ | F(FMA4) | F(TBM);
 339
 340         /* cpuid 0xC0000001.edx */
 341         const u32 kvm_supported_word5_x86_features =
 342                 F(XSTORE) | F(XSTORE_EN) | F(XCRYPT) | F(XCRYPT_EN) |
 343                 F(ACE2) | F(ACE2_EN) | F(PHE) | F(PHE_EN) |
 344                 F(PMM) | F(PMM_EN);
 345
 346         /* cpuid 7.0.ebx */
 347         const u32 kvm_supported_word9_x86_features =
 348                 F(FSGSBASE) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) |
 349                 F(BMI2) | F(ERMS) | f_invpcid | F(RTM) | f_mpx | F(RDSEED) |
 350                 F(ADX) | F(SMAP) | F(AVX512F) | F(AVX512PF) | F(AVX512ER) |
 351                 F(AVX512CD);
 352
 353         /* cpuid 0xD.1.eax */
 354         const u32 kvm_supported_word10_x86_features =
 355                 F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | f_xsaves;
 356
 357         /* all calls to cpuid_count() should be made on the same cpu */
 358         get_cpu();
 359
 360         r = -E2BIG;
 361
 362         if (*nent >= maxnent)
 363                 goto out;
 364
 365         do_cpuid_1_ent(entry, function, index);
 366         ++*nent;
 367
 368         switch (function) {
 369         case 0:
 370                 entry->eax = min(entry->eax, (u32)0xd);
 371                 break;
 372         case 1:
 373                 entry->edx &= kvm_supported_word0_x86_features;
 374                 cpuid_mask(&entry->edx, 0);
 375                 entry->ecx &= kvm_supported_word4_x86_features;
 376                 cpuid_mask(&entry->ecx, 4);
 377                 /* we support x2apic emulation even if host does not support
 378                  * it since we emulate x2apic in software */
 379                 entry->ecx |= F(X2APIC);
 380                 break;
 381         /* function 2 entries are STATEFUL. That is, repeated cpuid commands
 382          * may return different values. This forces us to get_cpu() before
 383          * issuing the first command, and also to emulate this annoying behavior
 384          * in kvm_emulate_cpuid() using KVM_CPUID_FLAG_STATE_READ_NEXT */
 385         case 2: {
 386                 int t, times = entry->eax & 0xff;
 387
 388                 entry->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
 389                 entry->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
 390                 for (t = 1; t < times; ++t) {
 391                         if (*nent >= maxnent)
 392                                 goto out;
 393
 394                         do_cpuid_1_ent(&entry[t], function, 0);
 395                         entry[t].flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
 396                         ++*nent;
 397                 }
 398                 break;
 399         }
 400         /* function 4 has additional index. */
 401         case 4: {
 402                 int i, cache_type;
 403
 404                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 405                 /* read more entries until cache_type is zero */
 406                 for (i = 1; ; ++i) {
 407                         if (*nent >= maxnent)
 408                                 goto out;
 409
 410                         cache_type = entry[i - 1].eax & 0x1f;
 411                         if (!cache_type)
 412                                 break;
 413                         do_cpuid_1_ent(&entry[i], function, i);
 414                         entry[i].flags |=
 415                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 416                         ++*nent;
 417                 }
 418                 break;
 419         }
 420         case 6: /* Thermal management */
 421                 entry->eax = 0x4; /* allow ARAT */
 422                 entry->ebx = 0;
 423                 entry->ecx = 0;
 424                 entry->edx = 0;
 425                 break;
 426         case 7: {
 427                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 428                 /* Mask ebx against host capability word 9 */
 429                 if (index == 0) {
 430                         entry->ebx &= kvm_supported_word9_x86_features;
 431                         cpuid_mask(&entry->ebx, 9);
 432                         // TSC_ADJUST is emulated
 433                         entry->ebx |= F(TSC_ADJUST);
 434                 } else
 435                         entry->ebx = 0;
 436                 entry->eax = 0;
 437                 entry->ecx = 0;
 438                 entry->edx = 0;
 439                 break;
 440         }
 441         case 9:
 442                 break;
 443         case 0xa: { /* Architectural Performance Monitoring */
 444                 struct x86_pmu_capability cap;
 445                 union cpuid10_eax eax;
 446                 union cpuid10_edx edx;
 447
 448                 perf_get_x86_pmu_capability(&cap);
 449
 450                 /*
 451                  * Only support guest architectural pmu on a host
 452                  * with architectural pmu.
 453                  */
 454                 if (!cap.version)
 455                         memset(&cap, 0, sizeof(cap));
 456
 457                 eax.split.version_id = min(cap.version, 2);
 458                 eax.split.num_counters = cap.num_counters_gp;
 459                 eax.split.bit_width = cap.bit_width_gp;
 460                 eax.split.mask_length = cap.events_mask_len;
 461
 462                 edx.split.num_counters_fixed = cap.num_counters_fixed;
 463                 edx.split.bit_width_fixed = cap.bit_width_fixed;
 464                 edx.split.reserved = 0;
 465
 466                 entry->eax = eax.full;
 467                 entry->ebx = cap.events_mask;
 468                 entry->ecx = 0;
 469                 entry->edx = edx.full;
 470                 break;
 471         }
 472         /* function 0xb has additional index. */
 473         case 0xb: {
 474                 int i, level_type;
 475
 476                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 477                 /* read more entries until level_type is zero */
 478                 for (i = 1; ; ++i) {
 479                         if (*nent >= maxnent)
 480                                 goto out;
 481
 482                         level_type = entry[i - 1].ecx & 0xff00;
 483                         if (!level_type)
 484                                 break;
 485                         do_cpuid_1_ent(&entry[i], function, i);
 486                         entry[i].flags |=
 487                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 488                         ++*nent;
 489                 }
 490                 break;
 491         }
 492         case 0xd: {
 493                 int idx, i;
 494                 u64 supported = kvm_supported_xcr0();
 495
 496                 entry->eax &= supported;
 497                 entry->ebx = xstate_required_size(supported, false);
 498                 entry->ecx = entry->ebx;
 499                 entry->edx &= supported >> 32;
 500                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 501                 if (!supported)
 502                         break;
 503
 504                 for (idx = 1, i = 1; idx < 64; ++idx) {
 505                         u64 mask = ((u64)1 << idx);
 506                         if (*nent >= maxnent)
 507                                 goto out;
 508
 509                         do_cpuid_1_ent(&entry[i], function, idx);
 510                         if (idx == 1) {
 511                                 entry[i].eax &= kvm_supported_word10_x86_features;
 512                                 entry[i].ebx = 0;
 513                                 if (entry[i].eax & (F(XSAVES)|F(XSAVEC)))
 514                                         entry[i].ebx =
 515                                                 xstate_required_size(supported,
 516                                                                      true);
 517                         } else {
 518                                 if (entry[i].eax == 0 || !(supported & mask))
 519                                         continue;
 520                                 if (WARN_ON_ONCE(entry[i].ecx & 1))
 521                                         continue;
 522                         }
 523                         entry[i].ecx = 0;
 524                         entry[i].edx = 0;
 525                         entry[i].flags |=
 526                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 527                         ++*nent;
 528                         ++i;
 529                 }
 530                 break;
 531         }
 532         case KVM_CPUID_SIGNATURE: {
 533                 static const char signature[12] = "KVMKVMKVM\0\0";
 534                 const u32 *sigptr = (const u32 *)signature;
 535                 entry->eax = KVM_CPUID_FEATURES;
 536                 entry->ebx = sigptr[0];
 537                 entry->ecx = sigptr[1];
 538                 entry->edx = sigptr[2];
 539                 break;
 540         }
 541         case KVM_CPUID_FEATURES:
 542                 entry->eax = (1 << KVM_FEATURE_CLOCKSOURCE) |
 543                              (1 << KVM_FEATURE_NOP_IO_DELAY) |
 544                              (1 << KVM_FEATURE_CLOCKSOURCE2) |
 545                              (1 << KVM_FEATURE_ASYNC_PF) |
 546                              (1 << KVM_FEATURE_PV_EOI) |
 547                              (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |
 548                              (1 << KVM_FEATURE_PV_UNHALT);
 549
 550                 if (sched_info_on())
 551                         entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
 552
 553                 entry->ebx = 0;
 554                 entry->ecx = 0;
 555                 entry->edx = 0;
 556                 break;
 557         case 0x80000000:
 558                 entry->eax = min(entry->eax, 0x8000001a);
 559                 break;
 560         case 0x80000001:
 561                 entry->edx &= kvm_supported_word1_x86_features;
 562                 cpuid_mask(&entry->edx, 1);
 563                 entry->ecx &= kvm_supported_word6_x86_features;
 564                 cpuid_mask(&entry->ecx, 6);
 565                 break;
 566         case 0x80000007: /* Advanced power management */
 567                 /* invariant TSC is CPUID.80000007H:EDX[8] */
 568                 entry->edx &= (1 << 8);
 569                 /* mask against host */
 570                 entry->edx &= boot_cpu_data.x86_power;
 571                 entry->eax = entry->ebx = entry->ecx = 0;
 572                 break;
 573         case 0x80000008: {
 574                 unsigned g_phys_as = (entry->eax >> 16) & 0xff;
 575                 unsigned virt_as = max((entry->eax >> 8) & 0xff, 48U);
 576                 unsigned phys_as = entry->eax & 0xff;
 577
 578                 if (!g_phys_as)
 579                         g_phys_as = phys_as;
 580                 entry->eax = g_phys_as | (virt_as << 8);
 581                 entry->ebx = entry->edx = 0;
 582                 break;
 583         }
 584         case 0x80000019:
 585                 entry->ecx = entry->edx = 0;
 586                 break;
 587         case 0x8000001a:
 588                 break;
 589         case 0x8000001d:
 590                 break;
 591         /*Add support for Centaur's CPUID instruction*/
 592         case 0xC0000000:
 593                 /*Just support up to 0xC0000004 now*/
 594                 entry->eax = min(entry->eax, 0xC0000004);
 595                 break;
 596         case 0xC0000001:
 597                 entry->edx &= kvm_supported_word5_x86_features;
 598                 cpuid_mask(&entry->edx, 5);
 599                 break;
 600         case 3: /* Processor serial number */
 601         case 5: /* MONITOR/MWAIT */
 602         case 0xC0000002:
 603         case 0xC0000003:
 604         case 0xC0000004:
 605         default:
 606                 entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
 607                 break;
 608         }
 609
 610         kvm_x86_ops->set_supported_cpuid(function, entry);
 611
 612         r = 0;
 613
 614 out:
 615         put_cpu();
 616
 617         return r;
 618 }
 619
 620 static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 func,
 621                         u32 idx, int *nent, int maxnent, unsigned int type)
 622 {
 623         if (type == KVM_GET_EMULATED_CPUID)
 624                 return __do_cpuid_ent_emulated(entry, func, idx, nent, maxnent);
 625
 626         return __do_cpuid_ent(entry, func, idx, nent, maxnent);
 627 }
 628
 629 #undef F
 630
 631 struct kvm_cpuid_param {
 632         u32 func;
 633         u32 idx;
 634         bool has_leaf_count;
 635         bool (*qualifier)(const struct kvm_cpuid_param *param);
 636 };
 637
 638 static bool is_centaur_cpu(const struct kvm_cpuid_param *param)
 639 {
 640         return boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR;
 641 }
 642
 643 static bool sanity_check_entries(struct kvm_cpuid_entry2 __user *entries,
 644                                  __u32 num_entries, unsigned int ioctl_type)
 645 {
 646         int i;
 647         __u32 pad[3];
 648
 649         if (ioctl_type != KVM_GET_EMULATED_CPUID)
 650                 return false;
 651
 652         /*
 653          * We want to make sure that ->padding is being passed clean from
 654          * userspace in case we want to use it for something in the future.
 655          *
 656          * Sadly, this wasn't enforced for KVM_GET_SUPPORTED_CPUID and so we
 657          * have to give ourselves satisfied only with the emulated side. /me
 658          * sheds a tear.
 659          */
 660         for (i = 0; i < num_entries; i++) {
 661                 if (copy_from_user(pad, entries[i].padding, sizeof(pad)))
 662                         return true;
 663
 664                 if (pad[0] || pad[1] || pad[2])
 665                         return true;
 666         }
 667         return false;
 668 }
 669
 670 int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
 671                             struct kvm_cpuid_entry2 __user *entries,
 672                             unsigned int type)
 673 {
 674         struct kvm_cpuid_entry2 *cpuid_entries;
 675         int limit, nent = 0, r = -E2BIG, i;
 676         u32 func;
 677         static const struct kvm_cpuid_param param[] = {
 678                 { .func = 0, .has_leaf_count = true },
 679                 { .func = 0x80000000, .has_leaf_count = true },
 680                 { .func = 0xC0000000, .qualifier = is_centaur_cpu, .has_leaf_count = true },
 681                 { .func = KVM_CPUID_SIGNATURE },
 682                 { .func = KVM_CPUID_FEATURES },
 683         };
 684
 685         if (cpuid->nent < 1)
 686                 goto out;
 687         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
 688                 cpuid->nent = KVM_MAX_CPUID_ENTRIES;
 689
 690         if (sanity_check_entries(entries, cpuid->nent, type))
 691                 return -EINVAL;
 692
 693         r = -ENOMEM;
 694         cpuid_entries = vzalloc(sizeof(struct kvm_cpuid_entry2) * cpuid->nent);
 695         if (!cpuid_entries)
 696                 goto out;
 697
 698         r = 0;
 699         for (i = 0; i < ARRAY_SIZE(param); i++) {
 700                 const struct kvm_cpuid_param *ent = &param[i];
 701
 702                 if (ent->qualifier && !ent->qualifier(ent))
 703                         continue;
 704
 705                 r = do_cpuid_ent(&cpuid_entries[nent], ent->func, ent->idx,
 706                                 &nent, cpuid->nent, type);
 707
 708                 if (r)
 709                         goto out_free;
 710
 711                 if (!ent->has_leaf_count)
 712                         continue;
 713
 714                 limit = cpuid_entries[nent - 1].eax;
 715                 for (func = ent->func + 1; func <= limit && nent < cpuid->nent && r == 0; ++func)
 716                         r = do_cpuid_ent(&cpuid_entries[nent], func, ent->idx,
 717                                      &nent, cpuid->nent, type);
 718
 719                 if (r)
 720                         goto out_free;
 721         }
 722
 723         r = -EFAULT;
 724         if (copy_to_user(entries, cpuid_entries,
 725                          nent * sizeof(struct kvm_cpuid_entry2)))
 726                 goto out_free;
 727         cpuid->nent = nent;
 728         r = 0;
 729
 730 out_free:
 731         vfree(cpuid_entries);
 732 out:
 733         return r;
 734 }
 735
 736 static int move_to_next_stateful_cpuid_entry(struct kvm_vcpu *vcpu, int i)
 737 {
 738         struct kvm_cpuid_entry2 *e = &vcpu->arch.cpuid_entries[i];
 739         int j, nent = vcpu->arch.cpuid_nent;
 740
 741         e->flags &= ~KVM_CPUID_FLAG_STATE_READ_NEXT;
 742         /* when no next entry is found, the current entry[i] is reselected */
 743         for (j = i + 1; ; j = (j + 1) % nent) {
 744                 struct kvm_cpuid_entry2 *ej = &vcpu->arch.cpuid_entries[j];
 745                 if (ej->function == e->function) {
 746                         ej->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
 747                         return j;
 748                 }
 749         }
 750         return 0; /* silence gcc, even though control never reaches here */
 751 }
 752
 753 /* find an entry with matching function, matching index (if needed), and that
 754  * should be read next (if it's stateful) */
 755 static int is_matching_cpuid_entry(struct kvm_cpuid_entry2 *e,
 756         u32 function, u32 index)
 757 {
 758         if (e->function != function)
 759                 return 0;
 760         if ((e->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX) && e->index != index)
 761                 return 0;
 762         if ((e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC) &&
 763             !(e->flags & KVM_CPUID_FLAG_STATE_READ_NEXT))
 764                 return 0;
 765         return 1;
 766 }
 767
 768 struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
 769                                               u32 function, u32 index)
 770 {
 771         int i;
 772         struct kvm_cpuid_entry2 *best = NULL;
 773
 774         for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
 775                 struct kvm_cpuid_entry2 *e;
 776
 777                 e = &vcpu->arch.cpuid_entries[i];
 778                 if (is_matching_cpuid_entry(e, function, index)) {
 779                         if (e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC)
 780                                 move_to_next_stateful_cpuid_entry(vcpu, i);
 781                         best = e;
 782                         break;
 783                 }
 784         }
 785         return best;
 786 }
 787 EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry);
 788
 789 /*
 790  * If no match is found, check whether we exceed the vCPU's limit
 791  * and return the content of the highest valid _standard_ leaf instead.
 792  * This is to satisfy the CPUID specification.
 793  */
 794 static struct kvm_cpuid_entry2* check_cpuid_limit(struct kvm_vcpu *vcpu,
 795                                                   u32 function, u32 index)
 796 {
 797         struct kvm_cpuid_entry2 *maxlevel;
 798
 799         maxlevel = kvm_find_cpuid_entry(vcpu, function & 0x80000000, 0);
 800         if (!maxlevel || maxlevel->eax >= function)
 801                 return NULL;
 802         if (function & 0x80000000) {
 803                 maxlevel = kvm_find_cpuid_entry(vcpu, 0, 0);
 804                 if (!maxlevel)
 805                         return NULL;
 806         }
 807         return kvm_find_cpuid_entry(vcpu, maxlevel->eax, index);
 808 }
 809
 810 void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)
 811 {
 812         u32 function = *eax, index = *ecx;
 813         struct kvm_cpuid_entry2 *best;
 814
 815         best = kvm_find_cpuid_entry(vcpu, function, index);
 816
 817         if (!best)
 818                 best = check_cpuid_limit(vcpu, function, index);
 819
 820         /*
 821          * Perfmon not yet supported for L2 guest.
 822          */
 823         if (is_guest_mode(vcpu) && function == 0xa)
 824                 best = NULL;
 825
 826         if (best) {
 827                 *eax = best->eax;
 828                 *ebx = best->ebx;
 829                 *ecx = best->ecx;
 830                 *edx = best->edx;
 831         } else
 832                 *eax = *ebx = *ecx = *edx = 0;
 833         trace_kvm_cpuid(function, *eax, *ebx, *ecx, *edx);
 834 }
 835 EXPORT_SYMBOL_GPL(kvm_cpuid);
 836
 837 void kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
 838 {
 839         u32 function, eax, ebx, ecx, edx;
 840
 841         function = eax = kvm_register_read(vcpu, VCPU_REGS_RAX);
 842         ecx = kvm_register_read(vcpu, VCPU_REGS_RCX);
 843         kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx);
 844         kvm_register_write(vcpu, VCPU_REGS_RAX, eax);
 845         kvm_register_write(vcpu, VCPU_REGS_RBX, ebx);
 846         kvm_register_write(vcpu, VCPU_REGS_RCX, ecx);
 847         kvm_register_write(vcpu, VCPU_REGS_RDX, edx);
 848         kvm_x86_ops->skip_emulated_instruction(vcpu);
 849 }
 850 EXPORT_SYMBOL_GPL(kvm_emulate_cpuid);