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/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 static u32 xstate_required_size(u64 xstate_bv)
  27 {
  28         int feature_bit = 0;
  29         u32 ret = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
  30
  31         xstate_bv &= XSTATE_EXTEND_MASK;
  32         while (xstate_bv) {
  33                 if (xstate_bv & 0x1) {
  34                         u32 eax, ebx, ecx, edx;
  35                         cpuid_count(0xD, feature_bit, &eax, &ebx, &ecx, &edx);
  36                         ret = max(ret, eax + ebx);
  37                 }
  38
  39                 xstate_bv >>= 1;
  40                 feature_bit++;
  41         }
  42
  43         return ret;
  44 }
  45
  46 u64 kvm_supported_xcr0(void)
  47 {
  48         u64 xcr0 = KVM_SUPPORTED_XCR0 & host_xcr0;
  49
  50         if (!kvm_x86_ops->mpx_supported())
  51                 xcr0 &= ~(XSTATE_BNDREGS | XSTATE_BNDCSR);
  52
  53         return xcr0;
  54 }
  55
  56 void kvm_update_cpuid(struct kvm_vcpu *vcpu)
  57 {
  58         struct kvm_cpuid_entry2 *best;
  59         struct kvm_lapic *apic = vcpu->arch.apic;
  60
  61         best = kvm_find_cpuid_entry(vcpu, 1, 0);
  62         if (!best)
  63                 return;
  64
  65         /* Update OSXSAVE bit */
  66         if (cpu_has_xsave && best->function == 0x1) {
  67                 best->ecx &= ~(bit(X86_FEATURE_OSXSAVE));
  68                 if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE))
  69                         best->ecx |= bit(X86_FEATURE_OSXSAVE);
  70         }
  71
  72         if (apic) {
  73                 if (best->ecx & bit(X86_FEATURE_TSC_DEADLINE_TIMER))
  74                         apic->lapic_timer.timer_mode_mask = 3 << 17;
  75                 else
  76                         apic->lapic_timer.timer_mode_mask = 1 << 17;
  77         }
  78
  79         best = kvm_find_cpuid_entry(vcpu, 0xD, 0);
  80         if (!best) {
  81                 vcpu->arch.guest_supported_xcr0 = 0;
  82                 vcpu->arch.guest_xstate_size = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
  83         } else {
  84                 vcpu->arch.guest_supported_xcr0 =
  85                         (best->eax | ((u64)best->edx << 32)) &
  86                         kvm_supported_xcr0();
  87                 vcpu->arch.guest_xstate_size = best->ebx =
  88                         xstate_required_size(vcpu->arch.xcr0);
  89         }
  90
  91         kvm_pmu_cpuid_update(vcpu);
  92 }
  93
  94 static int is_efer_nx(void)
  95 {
  96         unsigned long long efer = 0;
  97
  98         rdmsrl_safe(MSR_EFER, &efer);
  99         return efer & EFER_NX;
 100 }
 101
 102 static void cpuid_fix_nx_cap(struct kvm_vcpu *vcpu)
 103 {
 104         int i;
 105         struct kvm_cpuid_entry2 *e, *entry;
 106
 107         entry = NULL;
 108         for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
 109                 e = &vcpu->arch.cpuid_entries[i];
 110                 if (e->function == 0x80000001) {
 111                         entry = e;
 112                         break;
 113                 }
 114         }
 115         if (entry && (entry->edx & (1 << 20)) && !is_efer_nx()) {
 116                 entry->edx &= ~(1 << 20);
 117                 printk(KERN_INFO "kvm: guest NX capability removed\n");
 118         }
 119 }
 120
 121 /* when an old userspace process fills a new kernel module */
 122 int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
 123                              struct kvm_cpuid *cpuid,
 124                              struct kvm_cpuid_entry __user *entries)
 125 {
 126         int r, i;
 127         struct kvm_cpuid_entry *cpuid_entries;
 128
 129         r = -E2BIG;
 130         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
 131                 goto out;
 132         r = -ENOMEM;
 133         cpuid_entries = vmalloc(sizeof(struct kvm_cpuid_entry) * cpuid->nent);
 134         if (!cpuid_entries)
 135                 goto out;
 136         r = -EFAULT;
 137         if (copy_from_user(cpuid_entries, entries,
 138                            cpuid->nent * sizeof(struct kvm_cpuid_entry)))
 139                 goto out_free;
 140         for (i = 0; i < cpuid->nent; i++) {
 141                 vcpu->arch.cpuid_entries[i].function = cpuid_entries[i].function;
 142                 vcpu->arch.cpuid_entries[i].eax = cpuid_entries[i].eax;
 143                 vcpu->arch.cpuid_entries[i].ebx = cpuid_entries[i].ebx;
 144                 vcpu->arch.cpuid_entries[i].ecx = cpuid_entries[i].ecx;
 145                 vcpu->arch.cpuid_entries[i].edx = cpuid_entries[i].edx;
 146                 vcpu->arch.cpuid_entries[i].index = 0;
 147                 vcpu->arch.cpuid_entries[i].flags = 0;
 148                 vcpu->arch.cpuid_entries[i].padding[0] = 0;
 149                 vcpu->arch.cpuid_entries[i].padding[1] = 0;
 150                 vcpu->arch.cpuid_entries[i].padding[2] = 0;
 151         }
 152         vcpu->arch.cpuid_nent = cpuid->nent;
 153         cpuid_fix_nx_cap(vcpu);
 154         r = 0;
 155         kvm_apic_set_version(vcpu);
 156         kvm_x86_ops->cpuid_update(vcpu);
 157         kvm_update_cpuid(vcpu);
 158
 159 out_free:
 160         vfree(cpuid_entries);
 161 out:
 162         return r;
 163 }
 164
 165 int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
 166                               struct kvm_cpuid2 *cpuid,
 167                               struct kvm_cpuid_entry2 __user *entries)
 168 {
 169         int r;
 170
 171         r = -E2BIG;
 172         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
 173                 goto out;
 174         r = -EFAULT;
 175         if (copy_from_user(&vcpu->arch.cpuid_entries, entries,
 176                            cpuid->nent * sizeof(struct kvm_cpuid_entry2)))
 177                 goto out;
 178         vcpu->arch.cpuid_nent = cpuid->nent;
 179         kvm_apic_set_version(vcpu);
 180         kvm_x86_ops->cpuid_update(vcpu);
 181         kvm_update_cpuid(vcpu);
 182         return 0;
 183
 184 out:
 185         return r;
 186 }
 187
 188 int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
 189                               struct kvm_cpuid2 *cpuid,
 190                               struct kvm_cpuid_entry2 __user *entries)
 191 {
 192         int r;
 193
 194         r = -E2BIG;
 195         if (cpuid->nent < vcpu->arch.cpuid_nent)
 196                 goto out;
 197         r = -EFAULT;
 198         if (copy_to_user(entries, &vcpu->arch.cpuid_entries,
 199                          vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2)))
 200                 goto out;
 201         return 0;
 202
 203 out:
 204         cpuid->nent = vcpu->arch.cpuid_nent;
 205         return r;
 206 }
 207
 208 static void cpuid_mask(u32 *word, int wordnum)
 209 {
 210         *word &= boot_cpu_data.x86_capability[wordnum];
 211 }
 212
 213 static void do_cpuid_1_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 214                            u32 index)
 215 {
 216         entry->function = function;
 217         entry->index = index;
 218         cpuid_count(entry->function, entry->index,
 219                     &entry->eax, &entry->ebx, &entry->ecx, &entry->edx);
 220         entry->flags = 0;
 221 }
 222
 223 #define F(x) bit(X86_FEATURE_##x)
 224
 225 static int __do_cpuid_ent_emulated(struct kvm_cpuid_entry2 *entry,
 226                                    u32 func, u32 index, int *nent, int maxnent)
 227 {
 228         switch (func) {
 229         case 0:
 230                 entry->eax = 1;         /* only one leaf currently */
 231                 ++*nent;
 232                 break;
 233         case 1:
 234                 entry->ecx = F(MOVBE);
 235                 ++*nent;
 236                 break;
 237         default:
 238                 break;
 239         }
 240
 241         entry->function = func;
 242         entry->index = index;
 243
 244         return 0;
 245 }
 246
 247 static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 248                                  u32 index, int *nent, int maxnent)
 249 {
 250         int r;
 251         unsigned f_nx = is_efer_nx() ? F(NX) : 0;
 252 #ifdef CONFIG_X86_64
 253         unsigned f_gbpages = (kvm_x86_ops->get_lpage_level() == PT_PDPE_LEVEL)
 254                                 ? F(GBPAGES) : 0;
 255         unsigned f_lm = F(LM);
 256 #else
 257         unsigned f_gbpages = 0;
 258         unsigned f_lm = 0;
 259 #endif
 260         unsigned f_rdtscp = kvm_x86_ops->rdtscp_supported() ? F(RDTSCP) : 0;
 261         unsigned f_invpcid = kvm_x86_ops->invpcid_supported() ? F(INVPCID) : 0;
 262         unsigned f_mpx = kvm_x86_ops->mpx_supported() ? F(MPX) : 0;
 263
 264         /* cpuid 1.edx */
 265         const u32 kvm_supported_word0_x86_features =
 266                 F(FPU) | F(VME) | F(DE) | F(PSE) |
 267                 F(TSC) | F(MSR) | F(PAE) | F(MCE) |
 268                 F(CX8) | F(APIC) | 0 /* Reserved */ | F(SEP) |
 269                 F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
 270                 F(PAT) | F(PSE36) | 0 /* PSN */ | F(CLFLUSH) |
 271                 0 /* Reserved, DS, ACPI */ | F(MMX) |
 272                 F(FXSR) | F(XMM) | F(XMM2) | F(SELFSNOOP) |
 273                 0 /* HTT, TM, Reserved, PBE */;
 274         /* cpuid 0x80000001.edx */
 275         const u32 kvm_supported_word1_x86_features =
 276                 F(FPU) | F(VME) | F(DE) | F(PSE) |
 277                 F(TSC) | F(MSR) | F(PAE) | F(MCE) |
 278                 F(CX8) | F(APIC) | 0 /* Reserved */ | F(SYSCALL) |
 279                 F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
 280                 F(PAT) | F(PSE36) | 0 /* Reserved */ |
 281                 f_nx | 0 /* Reserved */ | F(MMXEXT) | F(MMX) |
 282                 F(FXSR) | F(FXSR_OPT) | f_gbpages | f_rdtscp |
 283                 0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW);
 284         /* cpuid 1.ecx */
 285         const u32 kvm_supported_word4_x86_features =
 286                 F(XMM3) | F(PCLMULQDQ) | 0 /* DTES64, MONITOR */ |
 287                 0 /* DS-CPL, VMX, SMX, EST */ |
 288                 0 /* TM2 */ | F(SSSE3) | 0 /* CNXT-ID */ | 0 /* Reserved */ |
 289                 F(FMA) | F(CX16) | 0 /* xTPR Update, PDCM */ |
 290                 F(PCID) | 0 /* Reserved, DCA */ | F(XMM4_1) |
 291                 F(XMM4_2) | F(X2APIC) | F(MOVBE) | F(POPCNT) |
 292                 0 /* Reserved*/ | F(AES) | F(XSAVE) | 0 /* OSXSAVE */ | F(AVX) |
 293                 F(F16C) | F(RDRAND);
 294         /* cpuid 0x80000001.ecx */
 295         const u32 kvm_supported_word6_x86_features =
 296                 F(LAHF_LM) | F(CMP_LEGACY) | 0 /*SVM*/ | 0 /* ExtApicSpace */ |
 297                 F(CR8_LEGACY) | F(ABM) | F(SSE4A) | F(MISALIGNSSE) |
 298                 F(3DNOWPREFETCH) | F(OSVW) | 0 /* IBS */ | F(XOP) |
 299                 0 /* SKINIT, WDT, LWP */ | F(FMA4) | F(TBM);
 300
 301         /* cpuid 0xC0000001.edx */
 302         const u32 kvm_supported_word5_x86_features =
 303                 F(XSTORE) | F(XSTORE_EN) | F(XCRYPT) | F(XCRYPT_EN) |
 304                 F(ACE2) | F(ACE2_EN) | F(PHE) | F(PHE_EN) |
 305                 F(PMM) | F(PMM_EN);
 306
 307         /* cpuid 7.0.ebx */
 308         const u32 kvm_supported_word9_x86_features =
 309                 F(FSGSBASE) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) |
 310                 F(BMI2) | F(ERMS) | f_invpcid | F(RTM) | f_mpx | F(RDSEED) |
 311                 F(ADX);
 312
 313         /* all calls to cpuid_count() should be made on the same cpu */
 314         get_cpu();
 315
 316         r = -E2BIG;
 317
 318         if (*nent >= maxnent)
 319                 goto out;
 320
 321         do_cpuid_1_ent(entry, function, index);
 322         ++*nent;
 323
 324         switch (function) {
 325         case 0:
 326                 entry->eax = min(entry->eax, (u32)0xd);
 327                 break;
 328         case 1:
 329                 entry->edx &= kvm_supported_word0_x86_features;
 330                 cpuid_mask(&entry->edx, 0);
 331                 entry->ecx &= kvm_supported_word4_x86_features;
 332                 cpuid_mask(&entry->ecx, 4);
 333                 /* we support x2apic emulation even if host does not support
 334                  * it since we emulate x2apic in software */
 335                 entry->ecx |= F(X2APIC);
 336                 break;
 337         /* function 2 entries are STATEFUL. That is, repeated cpuid commands
 338          * may return different values. This forces us to get_cpu() before
 339          * issuing the first command, and also to emulate this annoying behavior
 340          * in kvm_emulate_cpuid() using KVM_CPUID_FLAG_STATE_READ_NEXT */
 341         case 2: {
 342                 int t, times = entry->eax & 0xff;
 343
 344                 entry->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
 345                 entry->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
 346                 for (t = 1; t < times; ++t) {
 347                         if (*nent >= maxnent)
 348                                 goto out;
 349
 350                         do_cpuid_1_ent(&entry[t], function, 0);
 351                         entry[t].flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
 352                         ++*nent;
 353                 }
 354                 break;
 355         }
 356         /* function 4 has additional index. */
 357         case 4: {
 358                 int i, cache_type;
 359
 360                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 361                 /* read more entries until cache_type is zero */
 362                 for (i = 1; ; ++i) {
 363                         if (*nent >= maxnent)
 364                                 goto out;
 365
 366                         cache_type = entry[i - 1].eax & 0x1f;
 367                         if (!cache_type)
 368                                 break;
 369                         do_cpuid_1_ent(&entry[i], function, i);
 370                         entry[i].flags |=
 371                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 372                         ++*nent;
 373                 }
 374                 break;
 375         }
 376         case 7: {
 377                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 378                 /* Mask ebx against host capability word 9 */
 379                 if (index == 0) {
 380                         entry->ebx &= kvm_supported_word9_x86_features;
 381                         cpuid_mask(&entry->ebx, 9);
 382                         // TSC_ADJUST is emulated
 383                         entry->ebx |= F(TSC_ADJUST);
 384                 } else
 385                         entry->ebx = 0;
 386                 entry->eax = 0;
 387                 entry->ecx = 0;
 388                 entry->edx = 0;
 389                 break;
 390         }
 391         case 9:
 392                 break;
 393         case 0xa: { /* Architectural Performance Monitoring */
 394                 struct x86_pmu_capability cap;
 395                 union cpuid10_eax eax;
 396                 union cpuid10_edx edx;
 397
 398                 perf_get_x86_pmu_capability(&cap);
 399
 400                 /*
 401                  * Only support guest architectural pmu on a host
 402                  * with architectural pmu.
 403                  */
 404                 if (!cap.version)
 405                         memset(&cap, 0, sizeof(cap));
 406
 407                 eax.split.version_id = min(cap.version, 2);
 408                 eax.split.num_counters = cap.num_counters_gp;
 409                 eax.split.bit_width = cap.bit_width_gp;
 410                 eax.split.mask_length = cap.events_mask_len;
 411
 412                 edx.split.num_counters_fixed = cap.num_counters_fixed;
 413                 edx.split.bit_width_fixed = cap.bit_width_fixed;
 414                 edx.split.reserved = 0;
 415
 416                 entry->eax = eax.full;
 417                 entry->ebx = cap.events_mask;
 418                 entry->ecx = 0;
 419                 entry->edx = edx.full;
 420                 break;
 421         }
 422         /* function 0xb has additional index. */
 423         case 0xb: {
 424                 int i, level_type;
 425
 426                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 427                 /* read more entries until level_type is zero */
 428                 for (i = 1; ; ++i) {
 429                         if (*nent >= maxnent)
 430                                 goto out;
 431
 432                         level_type = entry[i - 1].ecx & 0xff00;
 433                         if (!level_type)
 434                                 break;
 435                         do_cpuid_1_ent(&entry[i], function, i);
 436                         entry[i].flags |=
 437                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 438                         ++*nent;
 439                 }
 440                 break;
 441         }
 442         case 0xd: {
 443                 int idx, i;
 444                 u64 supported = kvm_supported_xcr0();
 445
 446                 entry->eax &= supported;
 447                 entry->edx &= supported >> 32;
 448                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 449                 for (idx = 1, i = 1; idx < 64; ++idx) {
 450                         u64 mask = ((u64)1 << idx);
 451                         if (*nent >= maxnent)
 452                                 goto out;
 453
 454                         do_cpuid_1_ent(&entry[i], function, idx);
 455                         if (entry[i].eax == 0 || !(supported & mask))
 456                                 continue;
 457                         entry[i].flags |=
 458                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 459                         ++*nent;
 460                         ++i;
 461                 }
 462                 break;
 463         }
 464         case KVM_CPUID_SIGNATURE: {
 465                 static const char signature[12] = "KVMKVMKVM\0\0";
 466                 const u32 *sigptr = (const u32 *)signature;
 467                 entry->eax = KVM_CPUID_FEATURES;
 468                 entry->ebx = sigptr[0];
 469                 entry->ecx = sigptr[1];
 470                 entry->edx = sigptr[2];
 471                 break;
 472         }
 473         case KVM_CPUID_FEATURES:
 474                 entry->eax = (1 << KVM_FEATURE_CLOCKSOURCE) |
 475                              (1 << KVM_FEATURE_NOP_IO_DELAY) |
 476                              (1 << KVM_FEATURE_CLOCKSOURCE2) |
 477                              (1 << KVM_FEATURE_ASYNC_PF) |
 478                              (1 << KVM_FEATURE_PV_EOI) |
 479                              (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |
 480                              (1 << KVM_FEATURE_PV_UNHALT);
 481
 482                 if (sched_info_on())
 483                         entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
 484
 485                 entry->ebx = 0;
 486                 entry->ecx = 0;
 487                 entry->edx = 0;
 488                 break;
 489         case 0x80000000:
 490                 entry->eax = min(entry->eax, 0x8000001a);
 491                 break;
 492         case 0x80000001:
 493                 entry->edx &= kvm_supported_word1_x86_features;
 494                 cpuid_mask(&entry->edx, 1);
 495                 entry->ecx &= kvm_supported_word6_x86_features;
 496                 cpuid_mask(&entry->ecx, 6);
 497                 break;
 498         case 0x80000008: {
 499                 unsigned g_phys_as = (entry->eax >> 16) & 0xff;
 500                 unsigned virt_as = max((entry->eax >> 8) & 0xff, 48U);
 501                 unsigned phys_as = entry->eax & 0xff;
 502
 503                 if (!g_phys_as)
 504                         g_phys_as = phys_as;
 505                 entry->eax = g_phys_as | (virt_as << 8);
 506                 entry->ebx = entry->edx = 0;
 507                 break;
 508         }
 509         case 0x80000019:
 510                 entry->ecx = entry->edx = 0;
 511                 break;
 512         case 0x8000001a:
 513                 break;
 514         case 0x8000001d:
 515                 break;
 516         /*Add support for Centaur's CPUID instruction*/
 517         case 0xC0000000:
 518                 /*Just support up to 0xC0000004 now*/
 519                 entry->eax = min(entry->eax, 0xC0000004);
 520                 break;
 521         case 0xC0000001:
 522                 entry->edx &= kvm_supported_word5_x86_features;
 523                 cpuid_mask(&entry->edx, 5);
 524                 break;
 525         case 3: /* Processor serial number */
 526         case 5: /* MONITOR/MWAIT */
 527         case 6: /* Thermal management */
 528         case 0x80000007: /* Advanced power management */
 529         case 0xC0000002:
 530         case 0xC0000003:
 531         case 0xC0000004:
 532         default:
 533                 entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
 534                 break;
 535         }
 536
 537         kvm_x86_ops->set_supported_cpuid(function, entry);
 538
 539         r = 0;
 540
 541 out:
 542         put_cpu();
 543
 544         return r;
 545 }
 546
 547 static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 func,
 548                         u32 idx, int *nent, int maxnent, unsigned int type)
 549 {
 550         if (type == KVM_GET_EMULATED_CPUID)
 551                 return __do_cpuid_ent_emulated(entry, func, idx, nent, maxnent);
 552
 553         return __do_cpuid_ent(entry, func, idx, nent, maxnent);
 554 }
 555
 556 #undef F
 557
 558 struct kvm_cpuid_param {
 559         u32 func;
 560         u32 idx;
 561         bool has_leaf_count;
 562         bool (*qualifier)(const struct kvm_cpuid_param *param);
 563 };
 564
 565 static bool is_centaur_cpu(const struct kvm_cpuid_param *param)
 566 {
 567         return boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR;
 568 }
 569
 570 static bool sanity_check_entries(struct kvm_cpuid_entry2 __user *entries,
 571                                  __u32 num_entries, unsigned int ioctl_type)
 572 {
 573         int i;
 574         __u32 pad[3];
 575
 576         if (ioctl_type != KVM_GET_EMULATED_CPUID)
 577                 return false;
 578
 579         /*
 580          * We want to make sure that ->padding is being passed clean from
 581          * userspace in case we want to use it for something in the future.
 582          *
 583          * Sadly, this wasn't enforced for KVM_GET_SUPPORTED_CPUID and so we
 584          * have to give ourselves satisfied only with the emulated side. /me
 585          * sheds a tear.
 586          */
 587         for (i = 0; i < num_entries; i++) {
 588                 if (copy_from_user(pad, entries[i].padding, sizeof(pad)))
 589                         return true;
 590
 591                 if (pad[0] || pad[1] || pad[2])
 592                         return true;
 593         }
 594         return false;
 595 }
 596
 597 int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
 598                             struct kvm_cpuid_entry2 __user *entries,
 599                             unsigned int type)
 600 {
 601         struct kvm_cpuid_entry2 *cpuid_entries;
 602         int limit, nent = 0, r = -E2BIG, i;
 603         u32 func;
 604         static const struct kvm_cpuid_param param[] = {
 605                 { .func = 0, .has_leaf_count = true },
 606                 { .func = 0x80000000, .has_leaf_count = true },
 607                 { .func = 0xC0000000, .qualifier = is_centaur_cpu, .has_leaf_count = true },
 608                 { .func = KVM_CPUID_SIGNATURE },
 609                 { .func = KVM_CPUID_FEATURES },
 610         };
 611
 612         if (cpuid->nent < 1)
 613                 goto out;
 614         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
 615                 cpuid->nent = KVM_MAX_CPUID_ENTRIES;
 616
 617         if (sanity_check_entries(entries, cpuid->nent, type))
 618                 return -EINVAL;
 619
 620         r = -ENOMEM;
 621         cpuid_entries = vzalloc(sizeof(struct kvm_cpuid_entry2) * cpuid->nent);
 622         if (!cpuid_entries)
 623                 goto out;
 624
 625         r = 0;
 626         for (i = 0; i < ARRAY_SIZE(param); i++) {
 627                 const struct kvm_cpuid_param *ent = &param[i];
 628
 629                 if (ent->qualifier && !ent->qualifier(ent))
 630                         continue;
 631
 632                 r = do_cpuid_ent(&cpuid_entries[nent], ent->func, ent->idx,
 633                                 &nent, cpuid->nent, type);
 634
 635                 if (r)
 636                         goto out_free;
 637
 638                 if (!ent->has_leaf_count)
 639                         continue;
 640
 641                 limit = cpuid_entries[nent - 1].eax;
 642                 for (func = ent->func + 1; func <= limit && nent < cpuid->nent && r == 0; ++func)
 643                         r = do_cpuid_ent(&cpuid_entries[nent], func, ent->idx,
 644                                      &nent, cpuid->nent, type);
 645
 646                 if (r)
 647                         goto out_free;
 648         }
 649
 650         r = -EFAULT;
 651         if (copy_to_user(entries, cpuid_entries,
 652                          nent * sizeof(struct kvm_cpuid_entry2)))
 653                 goto out_free;
 654         cpuid->nent = nent;
 655         r = 0;
 656
 657 out_free:
 658         vfree(cpuid_entries);
 659 out:
 660         return r;
 661 }
 662
 663 static int move_to_next_stateful_cpuid_entry(struct kvm_vcpu *vcpu, int i)
 664 {
 665         struct kvm_cpuid_entry2 *e = &vcpu->arch.cpuid_entries[i];
 666         int j, nent = vcpu->arch.cpuid_nent;
 667
 668         e->flags &= ~KVM_CPUID_FLAG_STATE_READ_NEXT;
 669         /* when no next entry is found, the current entry[i] is reselected */
 670         for (j = i + 1; ; j = (j + 1) % nent) {
 671                 struct kvm_cpuid_entry2 *ej = &vcpu->arch.cpuid_entries[j];
 672                 if (ej->function == e->function) {
 673                         ej->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
 674                         return j;
 675                 }
 676         }
 677         return 0; /* silence gcc, even though control never reaches here */
 678 }
 679
 680 /* find an entry with matching function, matching index (if needed), and that
 681  * should be read next (if it's stateful) */
 682 static int is_matching_cpuid_entry(struct kvm_cpuid_entry2 *e,
 683         u32 function, u32 index)
 684 {
 685         if (e->function != function)
 686                 return 0;
 687         if ((e->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX) && e->index != index)
 688                 return 0;
 689         if ((e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC) &&
 690             !(e->flags & KVM_CPUID_FLAG_STATE_READ_NEXT))
 691                 return 0;
 692         return 1;
 693 }
 694
 695 struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
 696                                               u32 function, u32 index)
 697 {
 698         int i;
 699         struct kvm_cpuid_entry2 *best = NULL;
 700
 701         for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
 702                 struct kvm_cpuid_entry2 *e;
 703
 704                 e = &vcpu->arch.cpuid_entries[i];
 705                 if (is_matching_cpuid_entry(e, function, index)) {
 706                         if (e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC)
 707                                 move_to_next_stateful_cpuid_entry(vcpu, i);
 708                         best = e;
 709                         break;
 710                 }
 711         }
 712         return best;
 713 }
 714 EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry);
 715
 716 int cpuid_maxphyaddr(struct kvm_vcpu *vcpu)
 717 {
 718         struct kvm_cpuid_entry2 *best;
 719
 720         best = kvm_find_cpuid_entry(vcpu, 0x80000000, 0);
 721         if (!best || best->eax < 0x80000008)
 722                 goto not_found;
 723         best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
 724         if (best)
 725                 return best->eax & 0xff;
 726 not_found:
 727         return 36;
 728 }
 729
 730 /*
 731  * If no match is found, check whether we exceed the vCPU's limit
 732  * and return the content of the highest valid _standard_ leaf instead.
 733  * This is to satisfy the CPUID specification.
 734  */
 735 static struct kvm_cpuid_entry2* check_cpuid_limit(struct kvm_vcpu *vcpu,
 736                                                   u32 function, u32 index)
 737 {
 738         struct kvm_cpuid_entry2 *maxlevel;
 739
 740         maxlevel = kvm_find_cpuid_entry(vcpu, function & 0x80000000, 0);
 741         if (!maxlevel || maxlevel->eax >= function)
 742                 return NULL;
 743         if (function & 0x80000000) {
 744                 maxlevel = kvm_find_cpuid_entry(vcpu, 0, 0);
 745                 if (!maxlevel)
 746                         return NULL;
 747         }
 748         return kvm_find_cpuid_entry(vcpu, maxlevel->eax, index);
 749 }
 750
 751 void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)
 752 {
 753         u32 function = *eax, index = *ecx;
 754         struct kvm_cpuid_entry2 *best;
 755
 756         best = kvm_find_cpuid_entry(vcpu, function, index);
 757
 758         if (!best)
 759                 best = check_cpuid_limit(vcpu, function, index);
 760
 761         if (best) {
 762                 *eax = best->eax;
 763                 *ebx = best->ebx;
 764                 *ecx = best->ecx;
 765                 *edx = best->edx;
 766         } else
 767                 *eax = *ebx = *ecx = *edx = 0;
 768         trace_kvm_cpuid(function, *eax, *ebx, *ecx, *edx);
 769 }
 770 EXPORT_SYMBOL_GPL(kvm_cpuid);
 771
 772 void kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
 773 {
 774         u32 function, eax, ebx, ecx, edx;
 775
 776         function = eax = kvm_register_read(vcpu, VCPU_REGS_RAX);
 777         ecx = kvm_register_read(vcpu, VCPU_REGS_RCX);
 778         kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx);
 779         kvm_register_write(vcpu, VCPU_REGS_RAX, eax);
 780         kvm_register_write(vcpu, VCPU_REGS_RBX, ebx);
 781         kvm_register_write(vcpu, VCPU_REGS_RCX, ecx);
 782         kvm_register_write(vcpu, VCPU_REGS_RDX, edx);
 783         kvm_x86_ops->skip_emulated_instruction(vcpu);
 784 }
 785 EXPORT_SYMBOL_GPL(kvm_emulate_cpuid);