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_FPSSE;
  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 void kvm_update_cpuid(struct kvm_vcpu *vcpu)
  47 {
  48         struct kvm_cpuid_entry2 *best;
  49         struct kvm_lapic *apic = vcpu->arch.apic;
  50
  51         best = kvm_find_cpuid_entry(vcpu, 1, 0);
  52         if (!best)
  53                 return;
  54
  55         /* Update OSXSAVE bit */
  56         if (cpu_has_xsave && best->function == 0x1) {
  57                 best->ecx &= ~(bit(X86_FEATURE_OSXSAVE));
  58                 if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE))
  59                         best->ecx |= bit(X86_FEATURE_OSXSAVE);
  60         }
  61
  62         if (apic) {
  63                 if (best->ecx & bit(X86_FEATURE_TSC_DEADLINE_TIMER))
  64                         apic->lapic_timer.timer_mode_mask = 3 << 17;
  65                 else
  66                         apic->lapic_timer.timer_mode_mask = 1 << 17;
  67         }
  68
  69         best = kvm_find_cpuid_entry(vcpu, 0xD, 0);
  70         if (!best) {
  71                 vcpu->arch.guest_supported_xcr0 = 0;
  72                 vcpu->arch.guest_xstate_size = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
  73         } else {
  74                 vcpu->arch.guest_supported_xcr0 =
  75                         (best->eax | ((u64)best->edx << 32)) &
  76                         host_xcr0 & KVM_SUPPORTED_XCR0;
  77                 vcpu->arch.guest_xstate_size =
  78                         xstate_required_size(vcpu->arch.guest_supported_xcr0);
  79         }
  80
  81         kvm_pmu_cpuid_update(vcpu);
  82 }
  83
  84 static int is_efer_nx(void)
  85 {
  86         unsigned long long efer = 0;
  87
  88         rdmsrl_safe(MSR_EFER, &efer);
  89         return efer & EFER_NX;
  90 }
  91
  92 static void cpuid_fix_nx_cap(struct kvm_vcpu *vcpu)
  93 {
  94         int i;
  95         struct kvm_cpuid_entry2 *e, *entry;
  96
  97         entry = NULL;
  98         for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
  99                 e = &vcpu->arch.cpuid_entries[i];
 100                 if (e->function == 0x80000001) {
 101                         entry = e;
 102                         break;
 103                 }
 104         }
 105         if (entry && (entry->edx & (1 << 20)) && !is_efer_nx()) {
 106                 entry->edx &= ~(1 << 20);
 107                 printk(KERN_INFO "kvm: guest NX capability removed\n");
 108         }
 109 }
 110
 111 /* when an old userspace process fills a new kernel module */
 112 int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
 113                              struct kvm_cpuid *cpuid,
 114                              struct kvm_cpuid_entry __user *entries)
 115 {
 116         int r, i;
 117         struct kvm_cpuid_entry *cpuid_entries;
 118
 119         r = -E2BIG;
 120         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
 121                 goto out;
 122         r = -ENOMEM;
 123         cpuid_entries = vmalloc(sizeof(struct kvm_cpuid_entry) * cpuid->nent);
 124         if (!cpuid_entries)
 125                 goto out;
 126         r = -EFAULT;
 127         if (copy_from_user(cpuid_entries, entries,
 128                            cpuid->nent * sizeof(struct kvm_cpuid_entry)))
 129                 goto out_free;
 130         for (i = 0; i < cpuid->nent; i++) {
 131                 vcpu->arch.cpuid_entries[i].function = cpuid_entries[i].function;
 132                 vcpu->arch.cpuid_entries[i].eax = cpuid_entries[i].eax;
 133                 vcpu->arch.cpuid_entries[i].ebx = cpuid_entries[i].ebx;
 134                 vcpu->arch.cpuid_entries[i].ecx = cpuid_entries[i].ecx;
 135                 vcpu->arch.cpuid_entries[i].edx = cpuid_entries[i].edx;
 136                 vcpu->arch.cpuid_entries[i].index = 0;
 137                 vcpu->arch.cpuid_entries[i].flags = 0;
 138                 vcpu->arch.cpuid_entries[i].padding[0] = 0;
 139                 vcpu->arch.cpuid_entries[i].padding[1] = 0;
 140                 vcpu->arch.cpuid_entries[i].padding[2] = 0;
 141         }
 142         vcpu->arch.cpuid_nent = cpuid->nent;
 143         cpuid_fix_nx_cap(vcpu);
 144         r = 0;
 145         kvm_apic_set_version(vcpu);
 146         kvm_x86_ops->cpuid_update(vcpu);
 147         kvm_update_cpuid(vcpu);
 148
 149 out_free:
 150         vfree(cpuid_entries);
 151 out:
 152         return r;
 153 }
 154
 155 int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
 156                               struct kvm_cpuid2 *cpuid,
 157                               struct kvm_cpuid_entry2 __user *entries)
 158 {
 159         int r;
 160
 161         r = -E2BIG;
 162         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
 163                 goto out;
 164         r = -EFAULT;
 165         if (copy_from_user(&vcpu->arch.cpuid_entries, entries,
 166                            cpuid->nent * sizeof(struct kvm_cpuid_entry2)))
 167                 goto out;
 168         vcpu->arch.cpuid_nent = cpuid->nent;
 169         kvm_apic_set_version(vcpu);
 170         kvm_x86_ops->cpuid_update(vcpu);
 171         kvm_update_cpuid(vcpu);
 172         return 0;
 173
 174 out:
 175         return r;
 176 }
 177
 178 int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu,
 179                               struct kvm_cpuid2 *cpuid,
 180                               struct kvm_cpuid_entry2 __user *entries)
 181 {
 182         int r;
 183
 184         r = -E2BIG;
 185         if (cpuid->nent < vcpu->arch.cpuid_nent)
 186                 goto out;
 187         r = -EFAULT;
 188         if (copy_to_user(entries, &vcpu->arch.cpuid_entries,
 189                          vcpu->arch.cpuid_nent * sizeof(struct kvm_cpuid_entry2)))
 190                 goto out;
 191         return 0;
 192
 193 out:
 194         cpuid->nent = vcpu->arch.cpuid_nent;
 195         return r;
 196 }
 197
 198 static void cpuid_mask(u32 *word, int wordnum)
 199 {
 200         *word &= boot_cpu_data.x86_capability[wordnum];
 201 }
 202
 203 static void do_cpuid_1_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 204                            u32 index)
 205 {
 206         entry->function = function;
 207         entry->index = index;
 208         cpuid_count(entry->function, entry->index,
 209                     &entry->eax, &entry->ebx, &entry->ecx, &entry->edx);
 210         entry->flags = 0;
 211 }
 212
 213 static bool supported_xcr0_bit(unsigned bit)
 214 {
 215         u64 mask = ((u64)1 << bit);
 216
 217         return mask & KVM_SUPPORTED_XCR0 & host_xcr0;
 218 }
 219
 220 #define F(x) bit(X86_FEATURE_##x)
 221
 222 static int __do_cpuid_ent_emulated(struct kvm_cpuid_entry2 *entry,
 223                                    u32 func, u32 index, int *nent, int maxnent)
 224 {
 225         switch (func) {
 226         case 0:
 227                 entry->eax = 1;         /* only one leaf currently */
 228                 ++*nent;
 229                 break;
 230         case 1:
 231                 entry->ecx = F(MOVBE);
 232                 ++*nent;
 233                 break;
 234         default:
 235                 break;
 236         }
 237
 238         entry->function = func;
 239         entry->index = index;
 240
 241         return 0;
 242 }
 243
 244 static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 245                                  u32 index, int *nent, int maxnent)
 246 {
 247         int r;
 248         unsigned f_nx = is_efer_nx() ? F(NX) : 0;
 249 #ifdef CONFIG_X86_64
 250         unsigned f_gbpages = (kvm_x86_ops->get_lpage_level() == PT_PDPE_LEVEL)
 251                                 ? F(GBPAGES) : 0;
 252         unsigned f_lm = F(LM);
 253 #else
 254         unsigned f_gbpages = 0;
 255         unsigned f_lm = 0;
 256 #endif
 257         unsigned f_rdtscp = kvm_x86_ops->rdtscp_supported() ? F(RDTSCP) : 0;
 258         unsigned f_invpcid = kvm_x86_ops->invpcid_supported() ? F(INVPCID) : 0;
 259
 260         /* cpuid 1.edx */
 261         const u32 kvm_supported_word0_x86_features =
 262                 F(FPU) | F(VME) | F(DE) | F(PSE) |
 263                 F(TSC) | F(MSR) | F(PAE) | F(MCE) |
 264                 F(CX8) | F(APIC) | 0 /* Reserved */ | F(SEP) |
 265                 F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
 266                 F(PAT) | F(PSE36) | 0 /* PSN */ | F(CLFLSH) |
 267                 0 /* Reserved, DS, ACPI */ | F(MMX) |
 268                 F(FXSR) | F(XMM) | F(XMM2) | F(SELFSNOOP) |
 269                 0 /* HTT, TM, Reserved, PBE */;
 270         /* cpuid 0x80000001.edx */
 271         const u32 kvm_supported_word1_x86_features =
 272                 F(FPU) | F(VME) | F(DE) | F(PSE) |
 273                 F(TSC) | F(MSR) | F(PAE) | F(MCE) |
 274                 F(CX8) | F(APIC) | 0 /* Reserved */ | F(SYSCALL) |
 275                 F(MTRR) | F(PGE) | F(MCA) | F(CMOV) |
 276                 F(PAT) | F(PSE36) | 0 /* Reserved */ |
 277                 f_nx | 0 /* Reserved */ | F(MMXEXT) | F(MMX) |
 278                 F(FXSR) | F(FXSR_OPT) | f_gbpages | f_rdtscp |
 279                 0 /* Reserved */ | f_lm | F(3DNOWEXT) | F(3DNOW);
 280         /* cpuid 1.ecx */
 281         const u32 kvm_supported_word4_x86_features =
 282                 F(XMM3) | F(PCLMULQDQ) | 0 /* DTES64, MONITOR */ |
 283                 0 /* DS-CPL, VMX, SMX, EST */ |
 284                 0 /* TM2 */ | F(SSSE3) | 0 /* CNXT-ID */ | 0 /* Reserved */ |
 285                 F(FMA) | F(CX16) | 0 /* xTPR Update, PDCM */ |
 286                 F(PCID) | 0 /* Reserved, DCA */ | F(XMM4_1) |
 287                 F(XMM4_2) | F(X2APIC) | F(MOVBE) | F(POPCNT) |
 288                 0 /* Reserved*/ | F(AES) | F(XSAVE) | 0 /* OSXSAVE */ | F(AVX) |
 289                 F(F16C) | F(RDRAND);
 290         /* cpuid 0x80000001.ecx */
 291         const u32 kvm_supported_word6_x86_features =
 292                 F(LAHF_LM) | F(CMP_LEGACY) | 0 /*SVM*/ | 0 /* ExtApicSpace */ |
 293                 F(CR8_LEGACY) | F(ABM) | F(SSE4A) | F(MISALIGNSSE) |
 294                 F(3DNOWPREFETCH) | F(OSVW) | 0 /* IBS */ | F(XOP) |
 295                 0 /* SKINIT, WDT, LWP */ | F(FMA4) | F(TBM);
 296
 297         /* cpuid 0xC0000001.edx */
 298         const u32 kvm_supported_word5_x86_features =
 299                 F(XSTORE) | F(XSTORE_EN) | F(XCRYPT) | F(XCRYPT_EN) |
 300                 F(ACE2) | F(ACE2_EN) | F(PHE) | F(PHE_EN) |
 301                 F(PMM) | F(PMM_EN);
 302
 303         /* cpuid 7.0.ebx */
 304         const u32 kvm_supported_word9_x86_features =
 305                 F(FSGSBASE) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) |
 306                 F(BMI2) | F(ERMS) | f_invpcid | F(RTM);
 307
 308         /* all calls to cpuid_count() should be made on the same cpu */
 309         get_cpu();
 310
 311         r = -E2BIG;
 312
 313         if (*nent >= maxnent)
 314                 goto out;
 315
 316         do_cpuid_1_ent(entry, function, index);
 317         ++*nent;
 318
 319         switch (function) {
 320         case 0:
 321                 entry->eax = min(entry->eax, (u32)0xd);
 322                 break;
 323         case 1:
 324                 entry->edx &= kvm_supported_word0_x86_features;
 325                 cpuid_mask(&entry->edx, 0);
 326                 entry->ecx &= kvm_supported_word4_x86_features;
 327                 cpuid_mask(&entry->ecx, 4);
 328                 /* we support x2apic emulation even if host does not support
 329                  * it since we emulate x2apic in software */
 330                 entry->ecx |= F(X2APIC);
 331                 break;
 332         /* function 2 entries are STATEFUL. That is, repeated cpuid commands
 333          * may return different values. This forces us to get_cpu() before
 334          * issuing the first command, and also to emulate this annoying behavior
 335          * in kvm_emulate_cpuid() using KVM_CPUID_FLAG_STATE_READ_NEXT */
 336         case 2: {
 337                 int t, times = entry->eax & 0xff;
 338
 339                 entry->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
 340                 entry->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
 341                 for (t = 1; t < times; ++t) {
 342                         if (*nent >= maxnent)
 343                                 goto out;
 344
 345                         do_cpuid_1_ent(&entry[t], function, 0);
 346                         entry[t].flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
 347                         ++*nent;
 348                 }
 349                 break;
 350         }
 351         /* function 4 has additional index. */
 352         case 4: {
 353                 int i, cache_type;
 354
 355                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 356                 /* read more entries until cache_type is zero */
 357                 for (i = 1; ; ++i) {
 358                         if (*nent >= maxnent)
 359                                 goto out;
 360
 361                         cache_type = entry[i - 1].eax & 0x1f;
 362                         if (!cache_type)
 363                                 break;
 364                         do_cpuid_1_ent(&entry[i], function, i);
 365                         entry[i].flags |=
 366                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 367                         ++*nent;
 368                 }
 369                 break;
 370         }
 371         case 7: {
 372                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 373                 /* Mask ebx against host capability word 9 */
 374                 if (index == 0) {
 375                         entry->ebx &= kvm_supported_word9_x86_features;
 376                         cpuid_mask(&entry->ebx, 9);
 377                         // TSC_ADJUST is emulated
 378                         entry->ebx |= F(TSC_ADJUST);
 379                 } else
 380                         entry->ebx = 0;
 381                 entry->eax = 0;
 382                 entry->ecx = 0;
 383                 entry->edx = 0;
 384                 break;
 385         }
 386         case 9:
 387                 break;
 388         case 0xa: { /* Architectural Performance Monitoring */
 389                 struct x86_pmu_capability cap;
 390                 union cpuid10_eax eax;
 391                 union cpuid10_edx edx;
 392
 393                 perf_get_x86_pmu_capability(&cap);
 394
 395                 /*
 396                  * Only support guest architectural pmu on a host
 397                  * with architectural pmu.
 398                  */
 399                 if (!cap.version)
 400                         memset(&cap, 0, sizeof(cap));
 401
 402                 eax.split.version_id = min(cap.version, 2);
 403                 eax.split.num_counters = cap.num_counters_gp;
 404                 eax.split.bit_width = cap.bit_width_gp;
 405                 eax.split.mask_length = cap.events_mask_len;
 406
 407                 edx.split.num_counters_fixed = cap.num_counters_fixed;
 408                 edx.split.bit_width_fixed = cap.bit_width_fixed;
 409                 edx.split.reserved = 0;
 410
 411                 entry->eax = eax.full;
 412                 entry->ebx = cap.events_mask;
 413                 entry->ecx = 0;
 414                 entry->edx = edx.full;
 415                 break;
 416         }
 417         /* function 0xb has additional index. */
 418         case 0xb: {
 419                 int i, level_type;
 420
 421                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 422                 /* read more entries until level_type is zero */
 423                 for (i = 1; ; ++i) {
 424                         if (*nent >= maxnent)
 425                                 goto out;
 426
 427                         level_type = entry[i - 1].ecx & 0xff00;
 428                         if (!level_type)
 429                                 break;
 430                         do_cpuid_1_ent(&entry[i], function, i);
 431                         entry[i].flags |=
 432                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 433                         ++*nent;
 434                 }
 435                 break;
 436         }
 437         case 0xd: {
 438                 int idx, i;
 439
 440                 entry->eax &= host_xcr0 & KVM_SUPPORTED_XCR0;
 441                 entry->edx &= (host_xcr0 & KVM_SUPPORTED_XCR0) >> 32;
 442                 entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 443                 for (idx = 1, i = 1; idx < 64; ++idx) {
 444                         if (*nent >= maxnent)
 445                                 goto out;
 446
 447                         do_cpuid_1_ent(&entry[i], function, idx);
 448                         if (entry[i].eax == 0 || !supported_xcr0_bit(idx))
 449                                 continue;
 450                         entry[i].flags |=
 451                                KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
 452                         ++*nent;
 453                         ++i;
 454                 }
 455                 break;
 456         }
 457         case KVM_CPUID_SIGNATURE: {
 458                 static const char signature[12] = "KVMKVMKVM\0\0";
 459                 const u32 *sigptr = (const u32 *)signature;
 460                 entry->eax = KVM_CPUID_FEATURES;
 461                 entry->ebx = sigptr[0];
 462                 entry->ecx = sigptr[1];
 463                 entry->edx = sigptr[2];
 464                 break;
 465         }
 466         case KVM_CPUID_FEATURES:
 467                 entry->eax = (1 << KVM_FEATURE_CLOCKSOURCE) |
 468                              (1 << KVM_FEATURE_NOP_IO_DELAY) |
 469                              (1 << KVM_FEATURE_CLOCKSOURCE2) |
 470                              (1 << KVM_FEATURE_ASYNC_PF) |
 471                              (1 << KVM_FEATURE_PV_EOI) |
 472                              (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |
 473                              (1 << KVM_FEATURE_PV_UNHALT);
 474
 475                 if (sched_info_on())
 476                         entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);
 477
 478                 entry->ebx = 0;
 479                 entry->ecx = 0;
 480                 entry->edx = 0;
 481                 break;
 482         case 0x80000000:
 483                 entry->eax = min(entry->eax, 0x8000001a);
 484                 break;
 485         case 0x80000001:
 486                 entry->edx &= kvm_supported_word1_x86_features;
 487                 cpuid_mask(&entry->edx, 1);
 488                 entry->ecx &= kvm_supported_word6_x86_features;
 489                 cpuid_mask(&entry->ecx, 6);
 490                 break;
 491         case 0x80000008: {
 492                 unsigned g_phys_as = (entry->eax >> 16) & 0xff;
 493                 unsigned virt_as = max((entry->eax >> 8) & 0xff, 48U);
 494                 unsigned phys_as = entry->eax & 0xff;
 495
 496                 if (!g_phys_as)
 497                         g_phys_as = phys_as;
 498                 entry->eax = g_phys_as | (virt_as << 8);
 499                 entry->ebx = entry->edx = 0;
 500                 break;
 501         }
 502         case 0x80000019:
 503                 entry->ecx = entry->edx = 0;
 504                 break;
 505         case 0x8000001a:
 506                 break;
 507         case 0x8000001d:
 508                 break;
 509         /*Add support for Centaur's CPUID instruction*/
 510         case 0xC0000000:
 511                 /*Just support up to 0xC0000004 now*/
 512                 entry->eax = min(entry->eax, 0xC0000004);
 513                 break;
 514         case 0xC0000001:
 515                 entry->edx &= kvm_supported_word5_x86_features;
 516                 cpuid_mask(&entry->edx, 5);
 517                 break;
 518         case 3: /* Processor serial number */
 519         case 5: /* MONITOR/MWAIT */
 520         case 6: /* Thermal management */
 521         case 0x80000007: /* Advanced power management */
 522         case 0xC0000002:
 523         case 0xC0000003:
 524         case 0xC0000004:
 525         default:
 526                 entry->eax = entry->ebx = entry->ecx = entry->edx = 0;
 527                 break;
 528         }
 529
 530         kvm_x86_ops->set_supported_cpuid(function, entry);
 531
 532         r = 0;
 533
 534 out:
 535         put_cpu();
 536
 537         return r;
 538 }
 539
 540 static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 func,
 541                         u32 idx, int *nent, int maxnent, unsigned int type)
 542 {
 543         if (type == KVM_GET_EMULATED_CPUID)
 544                 return __do_cpuid_ent_emulated(entry, func, idx, nent, maxnent);
 545
 546         return __do_cpuid_ent(entry, func, idx, nent, maxnent);
 547 }
 548
 549 #undef F
 550
 551 struct kvm_cpuid_param {
 552         u32 func;
 553         u32 idx;
 554         bool has_leaf_count;
 555         bool (*qualifier)(const struct kvm_cpuid_param *param);
 556 };
 557
 558 static bool is_centaur_cpu(const struct kvm_cpuid_param *param)
 559 {
 560         return boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR;
 561 }
 562
 563 static bool sanity_check_entries(struct kvm_cpuid_entry2 __user *entries,
 564                                  __u32 num_entries, unsigned int ioctl_type)
 565 {
 566         int i;
 567         __u32 pad[3];
 568
 569         if (ioctl_type != KVM_GET_EMULATED_CPUID)
 570                 return false;
 571
 572         /*
 573          * We want to make sure that ->padding is being passed clean from
 574          * userspace in case we want to use it for something in the future.
 575          *
 576          * Sadly, this wasn't enforced for KVM_GET_SUPPORTED_CPUID and so we
 577          * have to give ourselves satisfied only with the emulated side. /me
 578          * sheds a tear.
 579          */
 580         for (i = 0; i < num_entries; i++) {
 581                 if (copy_from_user(pad, entries[i].padding, sizeof(pad)))
 582                         return true;
 583
 584                 if (pad[0] || pad[1] || pad[2])
 585                         return true;
 586         }
 587         return false;
 588 }
 589
 590 int kvm_dev_ioctl_get_cpuid(struct kvm_cpuid2 *cpuid,
 591                             struct kvm_cpuid_entry2 __user *entries,
 592                             unsigned int type)
 593 {
 594         struct kvm_cpuid_entry2 *cpuid_entries;
 595         int limit, nent = 0, r = -E2BIG, i;
 596         u32 func;
 597         static const struct kvm_cpuid_param param[] = {
 598                 { .func = 0, .has_leaf_count = true },
 599                 { .func = 0x80000000, .has_leaf_count = true },
 600                 { .func = 0xC0000000, .qualifier = is_centaur_cpu, .has_leaf_count = true },
 601                 { .func = KVM_CPUID_SIGNATURE },
 602                 { .func = KVM_CPUID_FEATURES },
 603         };
 604
 605         if (cpuid->nent < 1)
 606                 goto out;
 607         if (cpuid->nent > KVM_MAX_CPUID_ENTRIES)
 608                 cpuid->nent = KVM_MAX_CPUID_ENTRIES;
 609
 610         if (sanity_check_entries(entries, cpuid->nent, type))
 611                 return -EINVAL;
 612
 613         r = -ENOMEM;
 614         cpuid_entries = vzalloc(sizeof(struct kvm_cpuid_entry2) * cpuid->nent);
 615         if (!cpuid_entries)
 616                 goto out;
 617
 618         r = 0;
 619         for (i = 0; i < ARRAY_SIZE(param); i++) {
 620                 const struct kvm_cpuid_param *ent = &param[i];
 621
 622                 if (ent->qualifier && !ent->qualifier(ent))
 623                         continue;
 624
 625                 r = do_cpuid_ent(&cpuid_entries[nent], ent->func, ent->idx,
 626                                 &nent, cpuid->nent, type);
 627
 628                 if (r)
 629                         goto out_free;
 630
 631                 if (!ent->has_leaf_count)
 632                         continue;
 633
 634                 limit = cpuid_entries[nent - 1].eax;
 635                 for (func = ent->func + 1; func <= limit && nent < cpuid->nent && r == 0; ++func)
 636                         r = do_cpuid_ent(&cpuid_entries[nent], func, ent->idx,
 637                                      &nent, cpuid->nent, type);
 638
 639                 if (r)
 640                         goto out_free;
 641         }
 642
 643         r = -EFAULT;
 644         if (copy_to_user(entries, cpuid_entries,
 645                          nent * sizeof(struct kvm_cpuid_entry2)))
 646                 goto out_free;
 647         cpuid->nent = nent;
 648         r = 0;
 649
 650 out_free:
 651         vfree(cpuid_entries);
 652 out:
 653         return r;
 654 }
 655
 656 static int move_to_next_stateful_cpuid_entry(struct kvm_vcpu *vcpu, int i)
 657 {
 658         struct kvm_cpuid_entry2 *e = &vcpu->arch.cpuid_entries[i];
 659         int j, nent = vcpu->arch.cpuid_nent;
 660
 661         e->flags &= ~KVM_CPUID_FLAG_STATE_READ_NEXT;
 662         /* when no next entry is found, the current entry[i] is reselected */
 663         for (j = i + 1; ; j = (j + 1) % nent) {
 664                 struct kvm_cpuid_entry2 *ej = &vcpu->arch.cpuid_entries[j];
 665                 if (ej->function == e->function) {
 666                         ej->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
 667                         return j;
 668                 }
 669         }
 670         return 0; /* silence gcc, even though control never reaches here */
 671 }
 672
 673 /* find an entry with matching function, matching index (if needed), and that
 674  * should be read next (if it's stateful) */
 675 static int is_matching_cpuid_entry(struct kvm_cpuid_entry2 *e,
 676         u32 function, u32 index)
 677 {
 678         if (e->function != function)
 679                 return 0;
 680         if ((e->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX) && e->index != index)
 681                 return 0;
 682         if ((e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC) &&
 683             !(e->flags & KVM_CPUID_FLAG_STATE_READ_NEXT))
 684                 return 0;
 685         return 1;
 686 }
 687
 688 struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu,
 689                                               u32 function, u32 index)
 690 {
 691         int i;
 692         struct kvm_cpuid_entry2 *best = NULL;
 693
 694         for (i = 0; i < vcpu->arch.cpuid_nent; ++i) {
 695                 struct kvm_cpuid_entry2 *e;
 696
 697                 e = &vcpu->arch.cpuid_entries[i];
 698                 if (is_matching_cpuid_entry(e, function, index)) {
 699                         if (e->flags & KVM_CPUID_FLAG_STATEFUL_FUNC)
 700                                 move_to_next_stateful_cpuid_entry(vcpu, i);
 701                         best = e;
 702                         break;
 703                 }
 704         }
 705         return best;
 706 }
 707 EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry);
 708
 709 int cpuid_maxphyaddr(struct kvm_vcpu *vcpu)
 710 {
 711         struct kvm_cpuid_entry2 *best;
 712
 713         best = kvm_find_cpuid_entry(vcpu, 0x80000000, 0);
 714         if (!best || best->eax < 0x80000008)
 715                 goto not_found;
 716         best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0);
 717         if (best)
 718                 return best->eax & 0xff;
 719 not_found:
 720         return 36;
 721 }
 722
 723 /*
 724  * If no match is found, check whether we exceed the vCPU's limit
 725  * and return the content of the highest valid _standard_ leaf instead.
 726  * This is to satisfy the CPUID specification.
 727  */
 728 static struct kvm_cpuid_entry2* check_cpuid_limit(struct kvm_vcpu *vcpu,
 729                                                   u32 function, u32 index)
 730 {
 731         struct kvm_cpuid_entry2 *maxlevel;
 732
 733         maxlevel = kvm_find_cpuid_entry(vcpu, function & 0x80000000, 0);
 734         if (!maxlevel || maxlevel->eax >= function)
 735                 return NULL;
 736         if (function & 0x80000000) {
 737                 maxlevel = kvm_find_cpuid_entry(vcpu, 0, 0);
 738                 if (!maxlevel)
 739                         return NULL;
 740         }
 741         return kvm_find_cpuid_entry(vcpu, maxlevel->eax, index);
 742 }
 743
 744 void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)
 745 {
 746         u32 function = *eax, index = *ecx;
 747         struct kvm_cpuid_entry2 *best;
 748
 749         best = kvm_find_cpuid_entry(vcpu, function, index);
 750
 751         if (!best)
 752                 best = check_cpuid_limit(vcpu, function, index);
 753
 754         if (best) {
 755                 *eax = best->eax;
 756                 *ebx = best->ebx;
 757                 *ecx = best->ecx;
 758                 *edx = best->edx;
 759         } else
 760                 *eax = *ebx = *ecx = *edx = 0;
 761         trace_kvm_cpuid(function, *eax, *ebx, *ecx, *edx);
 762 }
 763 EXPORT_SYMBOL_GPL(kvm_cpuid);
 764
 765 void kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
 766 {
 767         u32 function, eax, ebx, ecx, edx;
 768
 769         function = eax = kvm_register_read(vcpu, VCPU_REGS_RAX);
 770         ecx = kvm_register_read(vcpu, VCPU_REGS_RCX);
 771         kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx);
 772         kvm_register_write(vcpu, VCPU_REGS_RAX, eax);
 773         kvm_register_write(vcpu, VCPU_REGS_RBX, ebx);
 774         kvm_register_write(vcpu, VCPU_REGS_RCX, ecx);
 775         kvm_register_write(vcpu, VCPU_REGS_RDX, edx);
 776         kvm_x86_ops->skip_emulated_instruction(vcpu);
 777 }
 778 EXPORT_SYMBOL_GPL(kvm_emulate_cpuid);