arch/x86/kvm/paging_tmpl.h

   1 /*
   2  * Kernel-based Virtual Machine driver for Linux
   3  *
   4  * This module enables machines with Intel VT-x extensions to run virtual
   5  * machines without emulation or binary translation.
   6  *
   7  * MMU support
   8  *
   9  * Copyright (C) 2006 Qumranet, Inc.
  10  * Copyright 2010 Red Hat, Inc. and/or its affiliates.
  11  *
  12  * Authors:
  13  *   Yaniv Kamay  <yaniv@qumranet.com>
  14  *   Avi Kivity   <avi@qumranet.com>
  15  *
  16  * This work is licensed under the terms of the GNU GPL, version 2.  See
  17  * the COPYING file in the top-level directory.
  18  *
  19  */
  20
  21 /*
  22  * We need the mmu code to access both 32-bit and 64-bit guest ptes,
  23  * so the code in this file is compiled twice, once per pte size.
  24  */
  25
  26 #if PTTYPE == 64
  27         #define pt_element_t u64
  28         #define guest_walker guest_walker64
  29         #define FNAME(name) paging##64_##name
  30         #define PT_BASE_ADDR_MASK PT64_BASE_ADDR_MASK
  31         #define PT_LVL_ADDR_MASK(lvl) PT64_LVL_ADDR_MASK(lvl)
  32         #define PT_LVL_OFFSET_MASK(lvl) PT64_LVL_OFFSET_MASK(lvl)
  33         #define PT_INDEX(addr, level) PT64_INDEX(addr, level)
  34         #define PT_LEVEL_MASK(level) PT64_LEVEL_MASK(level)
  35         #define PT_LEVEL_BITS PT64_LEVEL_BITS
  36         #ifdef CONFIG_X86_64
  37         #define PT_MAX_FULL_LEVELS 4
  38         #define CMPXCHG cmpxchg
  39         #else
  40         #define CMPXCHG cmpxchg64
  41         #define PT_MAX_FULL_LEVELS 2
  42         #endif
  43 #elif PTTYPE == 32
  44         #define pt_element_t u32
  45         #define guest_walker guest_walker32
  46         #define FNAME(name) paging##32_##name
  47         #define PT_BASE_ADDR_MASK PT32_BASE_ADDR_MASK
  48         #define PT_LVL_ADDR_MASK(lvl) PT32_LVL_ADDR_MASK(lvl)
  49         #define PT_LVL_OFFSET_MASK(lvl) PT32_LVL_OFFSET_MASK(lvl)
  50         #define PT_INDEX(addr, level) PT32_INDEX(addr, level)
  51         #define PT_LEVEL_MASK(level) PT32_LEVEL_MASK(level)
  52         #define PT_LEVEL_BITS PT32_LEVEL_BITS
  53         #define PT_MAX_FULL_LEVELS 2
  54         #define CMPXCHG cmpxchg
  55 #else
  56         #error Invalid PTTYPE value
  57 #endif
  58
  59 #define gpte_to_gfn_lvl FNAME(gpte_to_gfn_lvl)
  60 #define gpte_to_gfn(pte) gpte_to_gfn_lvl((pte), PT_PAGE_TABLE_LEVEL)
  61
  62 /*
  63  * The guest_walker structure emulates the behavior of the hardware page
  64  * table walker.
  65  */
  66 struct guest_walker {
  67         int level;
  68         gfn_t table_gfn[PT_MAX_FULL_LEVELS];
  69         pt_element_t ptes[PT_MAX_FULL_LEVELS];
  70         pt_element_t prefetch_ptes[PTE_PREFETCH_NUM];
  71         gpa_t pte_gpa[PT_MAX_FULL_LEVELS];
  72         unsigned pt_access;
  73         unsigned pte_access;
  74         gfn_t gfn;
  75         u32 error_code;
  76 };
  77
  78 static gfn_t gpte_to_gfn_lvl(pt_element_t gpte, int lvl)
  79 {
  80         return (gpte & PT_LVL_ADDR_MASK(lvl)) >> PAGE_SHIFT;
  81 }
  82
  83 static bool FNAME(cmpxchg_gpte)(struct kvm *kvm,
  84                          gfn_t table_gfn, unsigned index,
  85                          pt_element_t orig_pte, pt_element_t new_pte)
  86 {
  87         pt_element_t ret;
  88         pt_element_t *table;
  89         struct page *page;
  90
  91         page = gfn_to_page(kvm, table_gfn);
  92
  93         table = kmap_atomic(page, KM_USER0);
  94         ret = CMPXCHG(&table[index], orig_pte, new_pte);
  95         kunmap_atomic(table, KM_USER0);
  96
  97         kvm_release_page_dirty(page);
  98
  99         return (ret != orig_pte);
 100 }
 101
 102 static unsigned FNAME(gpte_access)(struct kvm_vcpu *vcpu, pt_element_t gpte)
 103 {
 104         unsigned access;
 105
 106         access = (gpte & (PT_WRITABLE_MASK | PT_USER_MASK)) | ACC_EXEC_MASK;
 107 #if PTTYPE == 64
 108         if (vcpu->arch.mmu.nx)
 109                 access &= ~(gpte >> PT64_NX_SHIFT);
 110 #endif
 111         return access;
 112 }
 113
 114 /*
 115  * Fetch a guest pte for a guest virtual address
 116  */
 117 static int FNAME(walk_addr_generic)(struct guest_walker *walker,
 118                                     struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
 119                                     gva_t addr, u32 access)
 120 {
 121         pt_element_t pte;
 122         gfn_t table_gfn;
 123         unsigned index, pt_access, uninitialized_var(pte_access);
 124         gpa_t pte_gpa;
 125         bool eperm, present, rsvd_fault;
 126         int offset, write_fault, user_fault, fetch_fault;
 127
 128         write_fault = access & PFERR_WRITE_MASK;
 129         user_fault = access & PFERR_USER_MASK;
 130         fetch_fault = access & PFERR_FETCH_MASK;
 131
 132         trace_kvm_mmu_pagetable_walk(addr, write_fault, user_fault,
 133                                      fetch_fault);
 134 walk:
 135         present = true;
 136         eperm = rsvd_fault = false;
 137         walker->level = mmu->root_level;
 138         pte           = mmu->get_cr3(vcpu);
 139
 140 #if PTTYPE == 64
 141         if (walker->level == PT32E_ROOT_LEVEL) {
 142                 pte = kvm_pdptr_read_mmu(vcpu, mmu, (addr >> 30) & 3);
 143                 trace_kvm_mmu_paging_element(pte, walker->level);
 144                 if (!is_present_gpte(pte)) {
 145                         present = false;
 146                         goto error;
 147                 }
 148                 --walker->level;
 149         }
 150 #endif
 151         ASSERT((!is_long_mode(vcpu) && is_pae(vcpu)) ||
 152                (mmu->get_cr3(vcpu) & CR3_NONPAE_RESERVED_BITS) == 0);
 153
 154         pt_access = ACC_ALL;
 155
 156         for (;;) {
 157                 index = PT_INDEX(addr, walker->level);
 158
 159                 table_gfn = gpte_to_gfn(pte);
 160                 offset    = index * sizeof(pt_element_t);
 161                 pte_gpa   = gfn_to_gpa(table_gfn) + offset;
 162                 walker->table_gfn[walker->level - 1] = table_gfn;
 163                 walker->pte_gpa[walker->level - 1] = pte_gpa;
 164
 165                 if (kvm_read_guest_page_mmu(vcpu, mmu, table_gfn, &pte,
 166                                             offset, sizeof(pte),
 167                                             PFERR_USER_MASK|PFERR_WRITE_MASK)) {
 168                         present = false;
 169                         break;
 170                 }
 171
 172                 trace_kvm_mmu_paging_element(pte, walker->level);
 173
 174                 if (!is_present_gpte(pte)) {
 175                         present = false;
 176                         break;
 177                 }
 178
 179                 if (is_rsvd_bits_set(&vcpu->arch.mmu, pte, walker->level)) {
 180                         rsvd_fault = true;
 181                         break;
 182                 }
 183
 184                 if (write_fault && !is_writable_pte(pte))
 185                         if (user_fault || is_write_protection(vcpu))
 186                                 eperm = true;
 187
 188                 if (user_fault && !(pte & PT_USER_MASK))
 189                         eperm = true;
 190
 191 #if PTTYPE == 64
 192                 if (fetch_fault && (pte & PT64_NX_MASK))
 193                         eperm = true;
 194 #endif
 195
 196                 if (!eperm && !rsvd_fault && !(pte & PT_ACCESSED_MASK)) {
 197                         trace_kvm_mmu_set_accessed_bit(table_gfn, index,
 198                                                        sizeof(pte));
 199                         if (FNAME(cmpxchg_gpte)(vcpu->kvm, table_gfn,
 200                             index, pte, pte|PT_ACCESSED_MASK))
 201                                 goto walk;
 202                         mark_page_dirty(vcpu->kvm, table_gfn);
 203                         pte |= PT_ACCESSED_MASK;
 204                 }
 205
 206                 pte_access = pt_access & FNAME(gpte_access)(vcpu, pte);
 207
 208                 walker->ptes[walker->level - 1] = pte;
 209
 210                 if ((walker->level == PT_PAGE_TABLE_LEVEL) ||
 211                     ((walker->level == PT_DIRECTORY_LEVEL) &&
 212                                 is_large_pte(pte) &&
 213                                 (PTTYPE == 64 || is_pse(vcpu))) ||
 214                     ((walker->level == PT_PDPE_LEVEL) &&
 215                                 is_large_pte(pte) &&
 216                                 mmu->root_level == PT64_ROOT_LEVEL)) {
 217                         int lvl = walker->level;
 218                         gpa_t real_gpa;
 219                         gfn_t gfn;
 220                         u32 ac;
 221
 222                         gfn = gpte_to_gfn_lvl(pte, lvl);
 223                         gfn += (addr & PT_LVL_OFFSET_MASK(lvl)) >> PAGE_SHIFT;
 224
 225                         if (PTTYPE == 32 &&
 226                             walker->level == PT_DIRECTORY_LEVEL &&
 227                             is_cpuid_PSE36())
 228                                 gfn += pse36_gfn_delta(pte);
 229
 230                         ac = write_fault | fetch_fault | user_fault;
 231
 232                         real_gpa = mmu->translate_gpa(vcpu, gfn_to_gpa(gfn),
 233                                                       ac);
 234                         if (real_gpa == UNMAPPED_GVA)
 235                                 return 0;
 236
 237                         walker->gfn = real_gpa >> PAGE_SHIFT;
 238
 239                         break;
 240                 }
 241
 242                 pt_access = pte_access;
 243                 --walker->level;
 244         }
 245
 246         if (!present || eperm || rsvd_fault)
 247                 goto error;
 248
 249         if (write_fault && !is_dirty_gpte(pte)) {
 250                 bool ret;
 251
 252                 trace_kvm_mmu_set_dirty_bit(table_gfn, index, sizeof(pte));
 253                 ret = FNAME(cmpxchg_gpte)(vcpu->kvm, table_gfn, index, pte,
 254                             pte|PT_DIRTY_MASK);
 255                 if (ret)
 256                         goto walk;
 257                 mark_page_dirty(vcpu->kvm, table_gfn);
 258                 pte |= PT_DIRTY_MASK;
 259                 walker->ptes[walker->level - 1] = pte;
 260         }
 261
 262         walker->pt_access = pt_access;
 263         walker->pte_access = pte_access;
 264         pgprintk("%s: pte %llx pte_access %x pt_access %x\n",
 265                  __func__, (u64)pte, pte_access, pt_access);
 266         return 1;
 267
 268 error:
 269         walker->error_code = 0;
 270         if (present)
 271                 walker->error_code |= PFERR_PRESENT_MASK;
 272
 273         walker->error_code |= write_fault | user_fault;
 274
 275         if (fetch_fault && mmu->nx)
 276                 walker->error_code |= PFERR_FETCH_MASK;
 277         if (rsvd_fault)
 278                 walker->error_code |= PFERR_RSVD_MASK;
 279
 280         vcpu->arch.fault.address    = addr;
 281         vcpu->arch.fault.error_code = walker->error_code;
 282
 283         trace_kvm_mmu_walker_error(walker->error_code);
 284         return 0;
 285 }
 286
 287 static int FNAME(walk_addr)(struct guest_walker *walker,
 288                             struct kvm_vcpu *vcpu, gva_t addr, u32 access)
 289 {
 290         return FNAME(walk_addr_generic)(walker, vcpu, &vcpu->arch.mmu, addr,
 291                                         access);
 292 }
 293
 294 static int FNAME(walk_addr_nested)(struct guest_walker *walker,
 295                                    struct kvm_vcpu *vcpu, gva_t addr,
 296                                    u32 access)
 297 {
 298         return FNAME(walk_addr_generic)(walker, vcpu, &vcpu->arch.nested_mmu,
 299                                         addr, access);
 300 }
 301
 302 static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
 303                               u64 *spte, const void *pte)
 304 {
 305         pt_element_t gpte;
 306         unsigned pte_access;
 307         pfn_t pfn;
 308         u64 new_spte;
 309
 310         gpte = *(const pt_element_t *)pte;
 311         if (~gpte & (PT_PRESENT_MASK | PT_ACCESSED_MASK)) {
 312                 if (!is_present_gpte(gpte)) {
 313                         if (sp->unsync)
 314                                 new_spte = shadow_trap_nonpresent_pte;
 315                         else
 316                                 new_spte = shadow_notrap_nonpresent_pte;
 317                         __set_spte(spte, new_spte);
 318                 }
 319                 return;
 320         }
 321         pgprintk("%s: gpte %llx spte %p\n", __func__, (u64)gpte, spte);
 322         pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte);
 323         if (gpte_to_gfn(gpte) != vcpu->arch.update_pte.gfn)
 324                 return;
 325         pfn = vcpu->arch.update_pte.pfn;
 326         if (is_error_pfn(pfn))
 327                 return;
 328         if (mmu_notifier_retry(vcpu, vcpu->arch.update_pte.mmu_seq))
 329                 return;
 330         kvm_get_pfn(pfn);
 331         /*
 332          * we call mmu_set_spte() with reset_host_protection = true beacuse that
 333          * vcpu->arch.update_pte.pfn was fetched from get_user_pages(write = 1).
 334          */
 335         mmu_set_spte(vcpu, spte, sp->role.access, pte_access, 0, 0,
 336                      is_dirty_gpte(gpte), NULL, PT_PAGE_TABLE_LEVEL,
 337                      gpte_to_gfn(gpte), pfn, true, true);
 338 }
 339
 340 static bool FNAME(gpte_changed)(struct kvm_vcpu *vcpu,
 341                                 struct guest_walker *gw, int level)
 342 {
 343         pt_element_t curr_pte;
 344         gpa_t base_gpa, pte_gpa = gw->pte_gpa[level - 1];
 345         u64 mask;
 346         int r, index;
 347
 348         if (level == PT_PAGE_TABLE_LEVEL) {
 349                 mask = PTE_PREFETCH_NUM * sizeof(pt_element_t) - 1;
 350                 base_gpa = pte_gpa & ~mask;
 351                 index = (pte_gpa - base_gpa) / sizeof(pt_element_t);
 352
 353                 r = kvm_read_guest_atomic(vcpu->kvm, base_gpa,
 354                                 gw->prefetch_ptes, sizeof(gw->prefetch_ptes));
 355                 curr_pte = gw->prefetch_ptes[index];
 356         } else
 357                 r = kvm_read_guest_atomic(vcpu->kvm, pte_gpa,
 358                                   &curr_pte, sizeof(curr_pte));
 359
 360         return r || curr_pte != gw->ptes[level - 1];
 361 }
 362
 363 static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, struct guest_walker *gw,
 364                                 u64 *sptep)
 365 {
 366         struct kvm_mmu_page *sp;
 367         struct kvm_mmu *mmu = &vcpu->arch.mmu;
 368         pt_element_t *gptep = gw->prefetch_ptes;
 369         u64 *spte;
 370         int i;
 371
 372         sp = page_header(__pa(sptep));
 373
 374         if (sp->role.level > PT_PAGE_TABLE_LEVEL)
 375                 return;
 376
 377         if (sp->role.direct)
 378                 return __direct_pte_prefetch(vcpu, sp, sptep);
 379
 380         i = (sptep - sp->spt) & ~(PTE_PREFETCH_NUM - 1);
 381         spte = sp->spt + i;
 382
 383         for (i = 0; i < PTE_PREFETCH_NUM; i++, spte++) {
 384                 pt_element_t gpte;
 385                 unsigned pte_access;
 386                 gfn_t gfn;
 387                 pfn_t pfn;
 388                 bool dirty;
 389
 390                 if (spte == sptep)
 391                         continue;
 392
 393                 if (*spte != shadow_trap_nonpresent_pte)
 394                         continue;
 395
 396                 gpte = gptep[i];
 397
 398                 if (!is_present_gpte(gpte) ||
 399                       is_rsvd_bits_set(mmu, gpte, PT_PAGE_TABLE_LEVEL)) {
 400                         if (!sp->unsync)
 401                                 __set_spte(spte, shadow_notrap_nonpresent_pte);
 402                         continue;
 403                 }
 404
 405                 if (!(gpte & PT_ACCESSED_MASK))
 406                         continue;
 407
 408                 pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte);
 409                 gfn = gpte_to_gfn(gpte);
 410                 dirty = is_dirty_gpte(gpte);
 411                 pfn = pte_prefetch_gfn_to_pfn(vcpu, gfn,
 412                                       (pte_access & ACC_WRITE_MASK) && dirty);
 413                 if (is_error_pfn(pfn)) {
 414                         kvm_release_pfn_clean(pfn);
 415                         break;
 416                 }
 417
 418                 mmu_set_spte(vcpu, spte, sp->role.access, pte_access, 0, 0,
 419                              dirty, NULL, PT_PAGE_TABLE_LEVEL, gfn,
 420                              pfn, true, true);
 421         }
 422 }
 423
 424 /*
 425  * Fetch a shadow pte for a specific level in the paging hierarchy.
 426  */
 427 static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr,
 428                          struct guest_walker *gw,
 429                          int user_fault, int write_fault, int hlevel,
 430                          int *ptwrite, pfn_t pfn)
 431 {
 432         unsigned access = gw->pt_access;
 433         struct kvm_mmu_page *sp = NULL;
 434         bool dirty = is_dirty_gpte(gw->ptes[gw->level - 1]);
 435         int top_level;
 436         unsigned direct_access;
 437         struct kvm_shadow_walk_iterator it;
 438
 439         if (!is_present_gpte(gw->ptes[gw->level - 1]))
 440                 return NULL;
 441
 442         direct_access = gw->pt_access & gw->pte_access;
 443         if (!dirty)
 444                 direct_access &= ~ACC_WRITE_MASK;
 445
 446         top_level = vcpu->arch.mmu.root_level;
 447         if (top_level == PT32E_ROOT_LEVEL)
 448                 top_level = PT32_ROOT_LEVEL;
 449         /*
 450          * Verify that the top-level gpte is still there.  Since the page
 451          * is a root page, it is either write protected (and cannot be
 452          * changed from now on) or it is invalid (in which case, we don't
 453          * really care if it changes underneath us after this point).
 454          */
 455         if (FNAME(gpte_changed)(vcpu, gw, top_level))
 456                 goto out_gpte_changed;
 457
 458         for (shadow_walk_init(&it, vcpu, addr);
 459              shadow_walk_okay(&it) && it.level > gw->level;
 460              shadow_walk_next(&it)) {
 461                 gfn_t table_gfn;
 462
 463                 drop_large_spte(vcpu, it.sptep);
 464
 465                 sp = NULL;
 466                 if (!is_shadow_present_pte(*it.sptep)) {
 467                         table_gfn = gw->table_gfn[it.level - 2];
 468                         sp = kvm_mmu_get_page(vcpu, table_gfn, addr, it.level-1,
 469                                               false, access, it.sptep);
 470                 }
 471
 472                 /*
 473                  * Verify that the gpte in the page we've just write
 474                  * protected is still there.
 475                  */
 476                 if (FNAME(gpte_changed)(vcpu, gw, it.level - 1))
 477                         goto out_gpte_changed;
 478
 479                 if (sp)
 480                         link_shadow_page(it.sptep, sp);
 481         }
 482
 483         for (;
 484              shadow_walk_okay(&it) && it.level > hlevel;
 485              shadow_walk_next(&it)) {
 486                 gfn_t direct_gfn;
 487
 488                 validate_direct_spte(vcpu, it.sptep, direct_access);
 489
 490                 drop_large_spte(vcpu, it.sptep);
 491
 492                 if (is_shadow_present_pte(*it.sptep))
 493                         continue;
 494
 495                 direct_gfn = gw->gfn & ~(KVM_PAGES_PER_HPAGE(it.level) - 1);
 496
 497                 sp = kvm_mmu_get_page(vcpu, direct_gfn, addr, it.level-1,
 498                                       true, direct_access, it.sptep);
 499                 link_shadow_page(it.sptep, sp);
 500         }
 501
 502         mmu_set_spte(vcpu, it.sptep, access, gw->pte_access & access,
 503                      user_fault, write_fault, dirty, ptwrite, it.level,
 504                      gw->gfn, pfn, false, true);
 505         FNAME(pte_prefetch)(vcpu, gw, it.sptep);
 506
 507         return it.sptep;
 508
 509 out_gpte_changed:
 510         if (sp)
 511                 kvm_mmu_put_page(sp, it.sptep);
 512         kvm_release_pfn_clean(pfn);
 513         return NULL;
 514 }
 515
 516 /*
 517  * Page fault handler.  There are several causes for a page fault:
 518  *   - there is no shadow pte for the guest pte
 519  *   - write access through a shadow pte marked read only so that we can set
 520  *     the dirty bit
 521  *   - write access to a shadow pte marked read only so we can update the page
 522  *     dirty bitmap, when userspace requests it
 523  *   - mmio access; in this case we will never install a present shadow pte
 524  *   - normal guest page fault due to the guest pte marked not present, not
 525  *     writable, or not executable
 526  *
 527  *  Returns: 1 if we need to emulate the instruction, 0 otherwise, or
 528  *           a negative value on error.
 529  */
 530 static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
 531                                u32 error_code)
 532 {
 533         int write_fault = error_code & PFERR_WRITE_MASK;
 534         int user_fault = error_code & PFERR_USER_MASK;
 535         struct guest_walker walker;
 536         u64 *sptep;
 537         int write_pt = 0;
 538         int r;
 539         pfn_t pfn;
 540         int level = PT_PAGE_TABLE_LEVEL;
 541         unsigned long mmu_seq;
 542
 543         pgprintk("%s: addr %lx err %x\n", __func__, addr, error_code);
 544
 545         r = mmu_topup_memory_caches(vcpu);
 546         if (r)
 547                 return r;
 548
 549         /*
 550          * Look up the guest pte for the faulting address.
 551          */
 552         r = FNAME(walk_addr)(&walker, vcpu, addr, error_code);
 553
 554         /*
 555          * The page is not mapped by the guest.  Let the guest handle it.
 556          */
 557         if (!r) {
 558                 pgprintk("%s: guest page fault\n", __func__);
 559                 inject_page_fault(vcpu);
 560                 vcpu->arch.last_pt_write_count = 0; /* reset fork detector */
 561                 return 0;
 562         }
 563
 564         if (walker.level >= PT_DIRECTORY_LEVEL) {
 565                 level = min(walker.level, mapping_level(vcpu, walker.gfn));
 566                 walker.gfn = walker.gfn & ~(KVM_PAGES_PER_HPAGE(level) - 1);
 567         }
 568
 569         mmu_seq = vcpu->kvm->mmu_notifier_seq;
 570         smp_rmb();
 571
 572         if (try_async_pf(vcpu, walker.gfn, addr, &pfn))
 573                 return 0;
 574
 575         /* mmio */
 576         if (is_error_pfn(pfn))
 577                 return kvm_handle_bad_page(vcpu->kvm, walker.gfn, pfn);
 578
 579         spin_lock(&vcpu->kvm->mmu_lock);
 580         if (mmu_notifier_retry(vcpu, mmu_seq))
 581                 goto out_unlock;
 582
 583         trace_kvm_mmu_audit(vcpu, AUDIT_PRE_PAGE_FAULT);
 584         kvm_mmu_free_some_pages(vcpu);
 585         sptep = FNAME(fetch)(vcpu, addr, &walker, user_fault, write_fault,
 586                              level, &write_pt, pfn);
 587         (void)sptep;
 588         pgprintk("%s: shadow pte %p %llx ptwrite %d\n", __func__,
 589                  sptep, *sptep, write_pt);
 590
 591         if (!write_pt)
 592                 vcpu->arch.last_pt_write_count = 0; /* reset fork detector */
 593
 594         ++vcpu->stat.pf_fixed;
 595         trace_kvm_mmu_audit(vcpu, AUDIT_POST_PAGE_FAULT);
 596         spin_unlock(&vcpu->kvm->mmu_lock);
 597
 598         return write_pt;
 599
 600 out_unlock:
 601         spin_unlock(&vcpu->kvm->mmu_lock);
 602         kvm_release_pfn_clean(pfn);
 603         return 0;
 604 }
 605
 606 static void FNAME(invlpg)(struct kvm_vcpu *vcpu, gva_t gva)
 607 {
 608         struct kvm_shadow_walk_iterator iterator;
 609         struct kvm_mmu_page *sp;
 610         gpa_t pte_gpa = -1;
 611         int level;
 612         u64 *sptep;
 613         int need_flush = 0;
 614
 615         spin_lock(&vcpu->kvm->mmu_lock);
 616
 617         for_each_shadow_entry(vcpu, gva, iterator) {
 618                 level = iterator.level;
 619                 sptep = iterator.sptep;
 620
 621                 sp = page_header(__pa(sptep));
 622                 if (is_last_spte(*sptep, level)) {
 623                         int offset, shift;
 624
 625                         if (!sp->unsync)
 626                                 break;
 627
 628                         shift = PAGE_SHIFT -
 629                                   (PT_LEVEL_BITS - PT64_LEVEL_BITS) * level;
 630                         offset = sp->role.quadrant << shift;
 631
 632                         pte_gpa = (sp->gfn << PAGE_SHIFT) + offset;
 633                         pte_gpa += (sptep - sp->spt) * sizeof(pt_element_t);
 634
 635                         if (is_shadow_present_pte(*sptep)) {
 636                                 if (is_large_pte(*sptep))
 637                                         --vcpu->kvm->stat.lpages;
 638                                 drop_spte(vcpu->kvm, sptep,
 639                                           shadow_trap_nonpresent_pte);
 640                                 need_flush = 1;
 641                         } else
 642                                 __set_spte(sptep, shadow_trap_nonpresent_pte);
 643                         break;
 644                 }
 645
 646                 if (!is_shadow_present_pte(*sptep) || !sp->unsync_children)
 647                         break;
 648         }
 649
 650         if (need_flush)
 651                 kvm_flush_remote_tlbs(vcpu->kvm);
 652
 653         atomic_inc(&vcpu->kvm->arch.invlpg_counter);
 654
 655         spin_unlock(&vcpu->kvm->mmu_lock);
 656
 657         if (pte_gpa == -1)
 658                 return;
 659
 660         if (mmu_topup_memory_caches(vcpu))
 661                 return;
 662         kvm_mmu_pte_write(vcpu, pte_gpa, NULL, sizeof(pt_element_t), 0);
 663 }
 664
 665 static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t vaddr, u32 access,
 666                                u32 *error)
 667 {
 668         struct guest_walker walker;
 669         gpa_t gpa = UNMAPPED_GVA;
 670         int r;
 671
 672         r = FNAME(walk_addr)(&walker, vcpu, vaddr, access);
 673
 674         if (r) {
 675                 gpa = gfn_to_gpa(walker.gfn);
 676                 gpa |= vaddr & ~PAGE_MASK;
 677         } else if (error)
 678                 *error = walker.error_code;
 679
 680         return gpa;
 681 }
 682
 683 static gpa_t FNAME(gva_to_gpa_nested)(struct kvm_vcpu *vcpu, gva_t vaddr,
 684                                       u32 access, u32 *error)
 685 {
 686         struct guest_walker walker;
 687         gpa_t gpa = UNMAPPED_GVA;
 688         int r;
 689
 690         r = FNAME(walk_addr_nested)(&walker, vcpu, vaddr, access);
 691
 692         if (r) {
 693                 gpa = gfn_to_gpa(walker.gfn);
 694                 gpa |= vaddr & ~PAGE_MASK;
 695         } else if (error)
 696                 *error = walker.error_code;
 697
 698         return gpa;
 699 }
 700
 701 static void FNAME(prefetch_page)(struct kvm_vcpu *vcpu,
 702                                  struct kvm_mmu_page *sp)
 703 {
 704         int i, j, offset, r;
 705         pt_element_t pt[256 / sizeof(pt_element_t)];
 706         gpa_t pte_gpa;
 707
 708         if (sp->role.direct
 709             || (PTTYPE == 32 && sp->role.level > PT_PAGE_TABLE_LEVEL)) {
 710                 nonpaging_prefetch_page(vcpu, sp);
 711                 return;
 712         }
 713
 714         pte_gpa = gfn_to_gpa(sp->gfn);
 715         if (PTTYPE == 32) {
 716                 offset = sp->role.quadrant << PT64_LEVEL_BITS;
 717                 pte_gpa += offset * sizeof(pt_element_t);
 718         }
 719
 720         for (i = 0; i < PT64_ENT_PER_PAGE; i += ARRAY_SIZE(pt)) {
 721                 r = kvm_read_guest_atomic(vcpu->kvm, pte_gpa, pt, sizeof pt);
 722                 pte_gpa += ARRAY_SIZE(pt) * sizeof(pt_element_t);
 723                 for (j = 0; j < ARRAY_SIZE(pt); ++j)
 724                         if (r || is_present_gpte(pt[j]))
 725                                 sp->spt[i+j] = shadow_trap_nonpresent_pte;
 726                         else
 727                                 sp->spt[i+j] = shadow_notrap_nonpresent_pte;
 728         }
 729 }
 730
 731 /*
 732  * Using the cached information from sp->gfns is safe because:
 733  * - The spte has a reference to the struct page, so the pfn for a given gfn
 734  *   can't change unless all sptes pointing to it are nuked first.
 735  */
 736 static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
 737                             bool clear_unsync)
 738 {
 739         int i, offset, nr_present;
 740         bool reset_host_protection;
 741         gpa_t first_pte_gpa;
 742
 743         offset = nr_present = 0;
 744
 745         /* direct kvm_mmu_page can not be unsync. */
 746         BUG_ON(sp->role.direct);
 747
 748         if (PTTYPE == 32)
 749                 offset = sp->role.quadrant << PT64_LEVEL_BITS;
 750
 751         first_pte_gpa = gfn_to_gpa(sp->gfn) + offset * sizeof(pt_element_t);
 752
 753         for (i = 0; i < PT64_ENT_PER_PAGE; i++) {
 754                 unsigned pte_access;
 755                 pt_element_t gpte;
 756                 gpa_t pte_gpa;
 757                 gfn_t gfn;
 758
 759                 if (!is_shadow_present_pte(sp->spt[i]))
 760                         continue;
 761
 762                 pte_gpa = first_pte_gpa + i * sizeof(pt_element_t);
 763
 764                 if (kvm_read_guest_atomic(vcpu->kvm, pte_gpa, &gpte,
 765                                           sizeof(pt_element_t)))
 766                         return -EINVAL;
 767
 768                 gfn = gpte_to_gfn(gpte);
 769                 if (is_rsvd_bits_set(&vcpu->arch.mmu, gpte, PT_PAGE_TABLE_LEVEL)
 770                       || gfn != sp->gfns[i] || !is_present_gpte(gpte)
 771                       || !(gpte & PT_ACCESSED_MASK)) {
 772                         u64 nonpresent;
 773
 774                         if (is_present_gpte(gpte) || !clear_unsync)
 775                                 nonpresent = shadow_trap_nonpresent_pte;
 776                         else
 777                                 nonpresent = shadow_notrap_nonpresent_pte;
 778                         drop_spte(vcpu->kvm, &sp->spt[i], nonpresent);
 779                         continue;
 780                 }
 781
 782                 nr_present++;
 783                 pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte);
 784                 if (!(sp->spt[i] & SPTE_HOST_WRITEABLE)) {
 785                         pte_access &= ~ACC_WRITE_MASK;
 786                         reset_host_protection = 0;
 787                 } else {
 788                         reset_host_protection = 1;
 789                 }
 790                 set_spte(vcpu, &sp->spt[i], pte_access, 0, 0,
 791                          is_dirty_gpte(gpte), PT_PAGE_TABLE_LEVEL, gfn,
 792                          spte_to_pfn(sp->spt[i]), true, false,
 793                          reset_host_protection);
 794         }
 795
 796         return !nr_present;
 797 }
 798
 799 #undef pt_element_t
 800 #undef guest_walker
 801 #undef FNAME
 802 #undef PT_BASE_ADDR_MASK
 803 #undef PT_INDEX
 804 #undef PT_LEVEL_MASK
 805 #undef PT_LVL_ADDR_MASK
 806 #undef PT_LVL_OFFSET_MASK
 807 #undef PT_LEVEL_BITS
 808 #undef PT_MAX_FULL_LEVELS
 809 #undef gpte_to_gfn
 810 #undef gpte_to_gfn_lvl
 811 #undef CMPXCHG