arch/x86/kvm/mmu.c

   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  *
  11  * Authors:
  12  *   Yaniv Kamay  <yaniv@qumranet.com>
  13  *   Avi Kivity   <avi@qumranet.com>
  14  *
  15  * This work is licensed under the terms of the GNU GPL, version 2.  See
  16  * the COPYING file in the top-level directory.
  17  *
  18  */
  19
  20 #include "mmu.h"
  21
  22 #include <linux/kvm_host.h>
  23 #include <linux/types.h>
  24 #include <linux/string.h>
  25 #include <linux/mm.h>
  26 #include <linux/highmem.h>
  27 #include <linux/module.h>
  28 #include <linux/swap.h>
  29 #include <linux/hugetlb.h>
  30 #include <linux/compiler.h>
  31
  32 #include <asm/page.h>
  33 #include <asm/cmpxchg.h>
  34 #include <asm/io.h>
  35 #include <asm/vmx.h>
  36
  37 /*
  38  * When setting this variable to true it enables Two-Dimensional-Paging
  39  * where the hardware walks 2 page tables:
  40  * 1. the guest-virtual to guest-physical
  41  * 2. while doing 1. it walks guest-physical to host-physical
  42  * If the hardware supports that we don't need to do shadow paging.
  43  */
  44 bool tdp_enabled = false;
  45
  46 #undef MMU_DEBUG
  47
  48 #undef AUDIT
  49
  50 #ifdef AUDIT
  51 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg);
  52 #else
  53 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg) {}
  54 #endif
  55
  56 #ifdef MMU_DEBUG
  57
  58 #define pgprintk(x...) do { if (dbg) printk(x); } while (0)
  59 #define rmap_printk(x...) do { if (dbg) printk(x); } while (0)
  60
  61 #else
  62
  63 #define pgprintk(x...) do { } while (0)
  64 #define rmap_printk(x...) do { } while (0)
  65
  66 #endif
  67
  68 #if defined(MMU_DEBUG) || defined(AUDIT)
  69 static int dbg = 0;
  70 module_param(dbg, bool, 0644);
  71 #endif
  72
  73 static int oos_shadow = 1;
  74 module_param(oos_shadow, bool, 0644);
  75
  76 #ifndef MMU_DEBUG
  77 #define ASSERT(x) do { } while (0)
  78 #else
  79 #define ASSERT(x)                                                       \
  80         if (!(x)) {                                                     \
  81                 printk(KERN_WARNING "assertion failed %s:%d: %s\n",     \
  82                        __FILE__, __LINE__, #x);                         \
  83         }
  84 #endif
  85
  86 #define PT_FIRST_AVAIL_BITS_SHIFT 9
  87 #define PT64_SECOND_AVAIL_BITS_SHIFT 52
  88
  89 #define VALID_PAGE(x) ((x) != INVALID_PAGE)
  90
  91 #define PT64_LEVEL_BITS 9
  92
  93 #define PT64_LEVEL_SHIFT(level) \
  94                 (PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS)
  95
  96 #define PT64_LEVEL_MASK(level) \
  97                 (((1ULL << PT64_LEVEL_BITS) - 1) << PT64_LEVEL_SHIFT(level))
  98
  99 #define PT64_INDEX(address, level)\
 100         (((address) >> PT64_LEVEL_SHIFT(level)) & ((1 << PT64_LEVEL_BITS) - 1))
 101
 102
 103 #define PT32_LEVEL_BITS 10
 104
 105 #define PT32_LEVEL_SHIFT(level) \
 106                 (PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS)
 107
 108 #define PT32_LEVEL_MASK(level) \
 109                 (((1ULL << PT32_LEVEL_BITS) - 1) << PT32_LEVEL_SHIFT(level))
 110
 111 #define PT32_INDEX(address, level)\
 112         (((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))
 113
 114
 115 #define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))
 116 #define PT64_DIR_BASE_ADDR_MASK \
 117         (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))
 118
 119 #define PT32_BASE_ADDR_MASK PAGE_MASK
 120 #define PT32_DIR_BASE_ADDR_MASK \
 121         (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
 122
 123 #define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK \
 124                         | PT64_NX_MASK)
 125
 126 #define PFERR_PRESENT_MASK (1U << 0)
 127 #define PFERR_WRITE_MASK (1U << 1)
 128 #define PFERR_USER_MASK (1U << 2)
 129 #define PFERR_FETCH_MASK (1U << 4)
 130
 131 #define PT_DIRECTORY_LEVEL 2
 132 #define PT_PAGE_TABLE_LEVEL 1
 133
 134 #define RMAP_EXT 4
 135
 136 #define ACC_EXEC_MASK    1
 137 #define ACC_WRITE_MASK   PT_WRITABLE_MASK
 138 #define ACC_USER_MASK    PT_USER_MASK
 139 #define ACC_ALL          (ACC_EXEC_MASK | ACC_WRITE_MASK | ACC_USER_MASK)
 140
 141 #define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)
 142
 143 struct kvm_rmap_desc {
 144         u64 *shadow_ptes[RMAP_EXT];
 145         struct kvm_rmap_desc *more;
 146 };
 147
 148 struct kvm_shadow_walk_iterator {
 149         u64 addr;
 150         hpa_t shadow_addr;
 151         int level;
 152         u64 *sptep;
 153         unsigned index;
 154 };
 155
 156 #define for_each_shadow_entry(_vcpu, _addr, _walker)    \
 157         for (shadow_walk_init(&(_walker), _vcpu, _addr);        \
 158              shadow_walk_okay(&(_walker));                      \
 159              shadow_walk_next(&(_walker)))
 160
 161
 162 struct kvm_unsync_walk {
 163         int (*entry) (struct kvm_mmu_page *sp, struct kvm_unsync_walk *walk);
 164 };
 165
 166 typedef int (*mmu_parent_walk_fn) (struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp);
 167
 168 static struct kmem_cache *pte_chain_cache;
 169 static struct kmem_cache *rmap_desc_cache;
 170 static struct kmem_cache *mmu_page_header_cache;
 171
 172 static u64 __read_mostly shadow_trap_nonpresent_pte;
 173 static u64 __read_mostly shadow_notrap_nonpresent_pte;
 174 static u64 __read_mostly shadow_base_present_pte;
 175 static u64 __read_mostly shadow_nx_mask;
 176 static u64 __read_mostly shadow_x_mask; /* mutual exclusive with nx_mask */
 177 static u64 __read_mostly shadow_user_mask;
 178 static u64 __read_mostly shadow_accessed_mask;
 179 static u64 __read_mostly shadow_dirty_mask;
 180 static u64 __read_mostly shadow_mt_mask;
 181
 182 void kvm_mmu_set_nonpresent_ptes(u64 trap_pte, u64 notrap_pte)
 183 {
 184         shadow_trap_nonpresent_pte = trap_pte;
 185         shadow_notrap_nonpresent_pte = notrap_pte;
 186 }
 187 EXPORT_SYMBOL_GPL(kvm_mmu_set_nonpresent_ptes);
 188
 189 void kvm_mmu_set_base_ptes(u64 base_pte)
 190 {
 191         shadow_base_present_pte = base_pte;
 192 }
 193 EXPORT_SYMBOL_GPL(kvm_mmu_set_base_ptes);
 194
 195 void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
 196                 u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 mt_mask)
 197 {
 198         shadow_user_mask = user_mask;
 199         shadow_accessed_mask = accessed_mask;
 200         shadow_dirty_mask = dirty_mask;
 201         shadow_nx_mask = nx_mask;
 202         shadow_x_mask = x_mask;
 203         shadow_mt_mask = mt_mask;
 204 }
 205 EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);
 206
 207 static int is_write_protection(struct kvm_vcpu *vcpu)
 208 {
 209         return vcpu->arch.cr0 & X86_CR0_WP;
 210 }
 211
 212 static int is_cpuid_PSE36(void)
 213 {
 214         return 1;
 215 }
 216
 217 static int is_nx(struct kvm_vcpu *vcpu)
 218 {
 219         return vcpu->arch.shadow_efer & EFER_NX;
 220 }
 221
 222 static int is_present_pte(unsigned long pte)
 223 {
 224         return pte & PT_PRESENT_MASK;
 225 }
 226
 227 static int is_shadow_present_pte(u64 pte)
 228 {
 229         return pte != shadow_trap_nonpresent_pte
 230                 && pte != shadow_notrap_nonpresent_pte;
 231 }
 232
 233 static int is_large_pte(u64 pte)
 234 {
 235         return pte & PT_PAGE_SIZE_MASK;
 236 }
 237
 238 static int is_writeble_pte(unsigned long pte)
 239 {
 240         return pte & PT_WRITABLE_MASK;
 241 }
 242
 243 static int is_dirty_pte(unsigned long pte)
 244 {
 245         return pte & shadow_dirty_mask;
 246 }
 247
 248 static int is_rmap_pte(u64 pte)
 249 {
 250         return is_shadow_present_pte(pte);
 251 }
 252
 253 static pfn_t spte_to_pfn(u64 pte)
 254 {
 255         return (pte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
 256 }
 257
 258 static gfn_t pse36_gfn_delta(u32 gpte)
 259 {
 260         int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT;
 261
 262         return (gpte & PT32_DIR_PSE36_MASK) << shift;
 263 }
 264
 265 static void set_shadow_pte(u64 *sptep, u64 spte)
 266 {
 267 #ifdef CONFIG_X86_64
 268         set_64bit((unsigned long *)sptep, spte);
 269 #else
 270         set_64bit((unsigned long long *)sptep, spte);
 271 #endif
 272 }
 273
 274 static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
 275                                   struct kmem_cache *base_cache, int min)
 276 {
 277         void *obj;
 278
 279         if (cache->nobjs >= min)
 280                 return 0;
 281         while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
 282                 obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
 283                 if (!obj)
 284                         return -ENOMEM;
 285                 cache->objects[cache->nobjs++] = obj;
 286         }
 287         return 0;
 288 }
 289
 290 static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
 291 {
 292         while (mc->nobjs)
 293                 kfree(mc->objects[--mc->nobjs]);
 294 }
 295
 296 static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
 297                                        int min)
 298 {
 299         struct page *page;
 300
 301         if (cache->nobjs >= min)
 302                 return 0;
 303         while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
 304                 page = alloc_page(GFP_KERNEL);
 305                 if (!page)
 306                         return -ENOMEM;
 307                 set_page_private(page, 0);
 308                 cache->objects[cache->nobjs++] = page_address(page);
 309         }
 310         return 0;
 311 }
 312
 313 static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
 314 {
 315         while (mc->nobjs)
 316                 free_page((unsigned long)mc->objects[--mc->nobjs]);
 317 }
 318
 319 static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
 320 {
 321         int r;
 322
 323         r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_chain_cache,
 324                                    pte_chain_cache, 4);
 325         if (r)
 326                 goto out;
 327         r = mmu_topup_memory_cache(&vcpu->arch.mmu_rmap_desc_cache,
 328                                    rmap_desc_cache, 4);
 329         if (r)
 330                 goto out;
 331         r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
 332         if (r)
 333                 goto out;
 334         r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
 335                                    mmu_page_header_cache, 4);
 336 out:
 337         return r;
 338 }
 339
 340 static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
 341 {
 342         mmu_free_memory_cache(&vcpu->arch.mmu_pte_chain_cache);
 343         mmu_free_memory_cache(&vcpu->arch.mmu_rmap_desc_cache);
 344         mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache);
 345         mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache);
 346 }
 347
 348 static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc,
 349                                     size_t size)
 350 {
 351         void *p;
 352
 353         BUG_ON(!mc->nobjs);
 354         p = mc->objects[--mc->nobjs];
 355         return p;
 356 }
 357
 358 static struct kvm_pte_chain *mmu_alloc_pte_chain(struct kvm_vcpu *vcpu)
 359 {
 360         return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_chain_cache,
 361                                       sizeof(struct kvm_pte_chain));
 362 }
 363
 364 static void mmu_free_pte_chain(struct kvm_pte_chain *pc)
 365 {
 366         kfree(pc);
 367 }
 368
 369 static struct kvm_rmap_desc *mmu_alloc_rmap_desc(struct kvm_vcpu *vcpu)
 370 {
 371         return mmu_memory_cache_alloc(&vcpu->arch.mmu_rmap_desc_cache,
 372                                       sizeof(struct kvm_rmap_desc));
 373 }
 374
 375 static void mmu_free_rmap_desc(struct kvm_rmap_desc *rd)
 376 {
 377         kfree(rd);
 378 }
 379
 380 /*
 381  * Return the pointer to the largepage write count for a given
 382  * gfn, handling slots that are not large page aligned.
 383  */
 384 static int *slot_largepage_idx(gfn_t gfn, struct kvm_memory_slot *slot)
 385 {
 386         unsigned long idx;
 387
 388         idx = (gfn / KVM_PAGES_PER_HPAGE) -
 389               (slot->base_gfn / KVM_PAGES_PER_HPAGE);
 390         return &slot->lpage_info[idx].write_count;
 391 }
 392
 393 static void account_shadowed(struct kvm *kvm, gfn_t gfn)
 394 {
 395         int *write_count;
 396
 397         gfn = unalias_gfn(kvm, gfn);
 398         write_count = slot_largepage_idx(gfn,
 399                                          gfn_to_memslot_unaliased(kvm, gfn));
 400         *write_count += 1;
 401 }
 402
 403 static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn)
 404 {
 405         int *write_count;
 406
 407         gfn = unalias_gfn(kvm, gfn);
 408         write_count = slot_largepage_idx(gfn,
 409                                          gfn_to_memslot_unaliased(kvm, gfn));
 410         *write_count -= 1;
 411         WARN_ON(*write_count < 0);
 412 }
 413
 414 static int has_wrprotected_page(struct kvm *kvm, gfn_t gfn)
 415 {
 416         struct kvm_memory_slot *slot;
 417         int *largepage_idx;
 418
 419         gfn = unalias_gfn(kvm, gfn);
 420         slot = gfn_to_memslot_unaliased(kvm, gfn);
 421         if (slot) {
 422                 largepage_idx = slot_largepage_idx(gfn, slot);
 423                 return *largepage_idx;
 424         }
 425
 426         return 1;
 427 }
 428
 429 static int host_largepage_backed(struct kvm *kvm, gfn_t gfn)
 430 {
 431         struct vm_area_struct *vma;
 432         unsigned long addr;
 433         int ret = 0;
 434
 435         addr = gfn_to_hva(kvm, gfn);
 436         if (kvm_is_error_hva(addr))
 437                 return ret;
 438
 439         down_read(&current->mm->mmap_sem);
 440         vma = find_vma(current->mm, addr);
 441         if (vma && is_vm_hugetlb_page(vma))
 442                 ret = 1;
 443         up_read(&current->mm->mmap_sem);
 444
 445         return ret;
 446 }
 447
 448 static int is_largepage_backed(struct kvm_vcpu *vcpu, gfn_t large_gfn)
 449 {
 450         struct kvm_memory_slot *slot;
 451
 452         if (has_wrprotected_page(vcpu->kvm, large_gfn))
 453                 return 0;
 454
 455         if (!host_largepage_backed(vcpu->kvm, large_gfn))
 456                 return 0;
 457
 458         slot = gfn_to_memslot(vcpu->kvm, large_gfn);
 459         if (slot && slot->dirty_bitmap)
 460                 return 0;
 461
 462         return 1;
 463 }
 464
 465 /*
 466  * Take gfn and return the reverse mapping to it.
 467  * Note: gfn must be unaliased before this function get called
 468  */
 469
 470 static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int lpage)
 471 {
 472         struct kvm_memory_slot *slot;
 473         unsigned long idx;
 474
 475         slot = gfn_to_memslot(kvm, gfn);
 476         if (!lpage)
 477                 return &slot->rmap[gfn - slot->base_gfn];
 478
 479         idx = (gfn / KVM_PAGES_PER_HPAGE) -
 480               (slot->base_gfn / KVM_PAGES_PER_HPAGE);
 481
 482         return &slot->lpage_info[idx].rmap_pde;
 483 }
 484
 485 /*
 486  * Reverse mapping data structures:
 487  *
 488  * If rmapp bit zero is zero, then rmapp point to the shadw page table entry
 489  * that points to page_address(page).
 490  *
 491  * If rmapp bit zero is one, (then rmap & ~1) points to a struct kvm_rmap_desc
 492  * containing more mappings.
 493  */
 494 static void rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn, int lpage)
 495 {
 496         struct kvm_mmu_page *sp;
 497         struct kvm_rmap_desc *desc;
 498         unsigned long *rmapp;
 499         int i;
 500
 501         if (!is_rmap_pte(*spte))
 502                 return;
 503         gfn = unalias_gfn(vcpu->kvm, gfn);
 504         sp = page_header(__pa(spte));
 505         sp->gfns[spte - sp->spt] = gfn;
 506         rmapp = gfn_to_rmap(vcpu->kvm, gfn, lpage);
 507         if (!*rmapp) {
 508                 rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte);
 509                 *rmapp = (unsigned long)spte;
 510         } else if (!(*rmapp & 1)) {
 511                 rmap_printk("rmap_add: %p %llx 1->many\n", spte, *spte);
 512                 desc = mmu_alloc_rmap_desc(vcpu);
 513                 desc->shadow_ptes[0] = (u64 *)*rmapp;
 514                 desc->shadow_ptes[1] = spte;
 515                 *rmapp = (unsigned long)desc | 1;
 516         } else {
 517                 rmap_printk("rmap_add: %p %llx many->many\n", spte, *spte);
 518                 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
 519                 while (desc->shadow_ptes[RMAP_EXT-1] && desc->more)
 520                         desc = desc->more;
 521                 if (desc->shadow_ptes[RMAP_EXT-1]) {
 522                         desc->more = mmu_alloc_rmap_desc(vcpu);
 523                         desc = desc->more;
 524                 }
 525                 for (i = 0; desc->shadow_ptes[i]; ++i)
 526                         ;
 527                 desc->shadow_ptes[i] = spte;
 528         }
 529 }
 530
 531 static void rmap_desc_remove_entry(unsigned long *rmapp,
 532                                    struct kvm_rmap_desc *desc,
 533                                    int i,
 534                                    struct kvm_rmap_desc *prev_desc)
 535 {
 536         int j;
 537
 538         for (j = RMAP_EXT - 1; !desc->shadow_ptes[j] && j > i; --j)
 539                 ;
 540         desc->shadow_ptes[i] = desc->shadow_ptes[j];
 541         desc->shadow_ptes[j] = NULL;
 542         if (j != 0)
 543                 return;
 544         if (!prev_desc && !desc->more)
 545                 *rmapp = (unsigned long)desc->shadow_ptes[0];
 546         else
 547                 if (prev_desc)
 548                         prev_desc->more = desc->more;
 549                 else
 550                         *rmapp = (unsigned long)desc->more | 1;
 551         mmu_free_rmap_desc(desc);
 552 }
 553
 554 static void rmap_remove(struct kvm *kvm, u64 *spte)
 555 {
 556         struct kvm_rmap_desc *desc;
 557         struct kvm_rmap_desc *prev_desc;
 558         struct kvm_mmu_page *sp;
 559         pfn_t pfn;
 560         unsigned long *rmapp;
 561         int i;
 562
 563         if (!is_rmap_pte(*spte))
 564                 return;
 565         sp = page_header(__pa(spte));
 566         pfn = spte_to_pfn(*spte);
 567         if (*spte & shadow_accessed_mask)
 568                 kvm_set_pfn_accessed(pfn);
 569         if (is_writeble_pte(*spte))
 570                 kvm_release_pfn_dirty(pfn);
 571         else
 572                 kvm_release_pfn_clean(pfn);
 573         rmapp = gfn_to_rmap(kvm, sp->gfns[spte - sp->spt], is_large_pte(*spte));
 574         if (!*rmapp) {
 575                 printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte);
 576                 BUG();
 577         } else if (!(*rmapp & 1)) {
 578                 rmap_printk("rmap_remove:  %p %llx 1->0\n", spte, *spte);
 579                 if ((u64 *)*rmapp != spte) {
 580                         printk(KERN_ERR "rmap_remove:  %p %llx 1->BUG\n",
 581                                spte, *spte);
 582                         BUG();
 583                 }
 584                 *rmapp = 0;
 585         } else {
 586                 rmap_printk("rmap_remove:  %p %llx many->many\n", spte, *spte);
 587                 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
 588                 prev_desc = NULL;
 589                 while (desc) {
 590                         for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i)
 591                                 if (desc->shadow_ptes[i] == spte) {
 592                                         rmap_desc_remove_entry(rmapp,
 593                                                                desc, i,
 594                                                                prev_desc);
 595                                         return;
 596                                 }
 597                         prev_desc = desc;
 598                         desc = desc->more;
 599                 }
 600                 BUG();
 601         }
 602 }
 603
 604 static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte)
 605 {
 606         struct kvm_rmap_desc *desc;
 607         struct kvm_rmap_desc *prev_desc;
 608         u64 *prev_spte;
 609         int i;
 610
 611         if (!*rmapp)
 612                 return NULL;
 613         else if (!(*rmapp & 1)) {
 614                 if (!spte)
 615                         return (u64 *)*rmapp;
 616                 return NULL;
 617         }
 618         desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
 619         prev_desc = NULL;
 620         prev_spte = NULL;
 621         while (desc) {
 622                 for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i) {
 623                         if (prev_spte == spte)
 624                                 return desc->shadow_ptes[i];
 625                         prev_spte = desc->shadow_ptes[i];
 626                 }
 627                 desc = desc->more;
 628         }
 629         return NULL;
 630 }
 631
 632 static int rmap_write_protect(struct kvm *kvm, u64 gfn)
 633 {
 634         unsigned long *rmapp;
 635         u64 *spte;
 636         int write_protected = 0;
 637
 638         gfn = unalias_gfn(kvm, gfn);
 639         rmapp = gfn_to_rmap(kvm, gfn, 0);
 640
 641         spte = rmap_next(kvm, rmapp, NULL);
 642         while (spte) {
 643                 BUG_ON(!spte);
 644                 BUG_ON(!(*spte & PT_PRESENT_MASK));
 645                 rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
 646                 if (is_writeble_pte(*spte)) {
 647                         set_shadow_pte(spte, *spte & ~PT_WRITABLE_MASK);
 648                         write_protected = 1;
 649                 }
 650                 spte = rmap_next(kvm, rmapp, spte);
 651         }
 652         if (write_protected) {
 653                 pfn_t pfn;
 654
 655                 spte = rmap_next(kvm, rmapp, NULL);
 656                 pfn = spte_to_pfn(*spte);
 657                 kvm_set_pfn_dirty(pfn);
 658         }
 659
 660         /* check for huge page mappings */
 661         rmapp = gfn_to_rmap(kvm, gfn, 1);
 662         spte = rmap_next(kvm, rmapp, NULL);
 663         while (spte) {
 664                 BUG_ON(!spte);
 665                 BUG_ON(!(*spte & PT_PRESENT_MASK));
 666                 BUG_ON((*spte & (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK)) != (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK));
 667                 pgprintk("rmap_write_protect(large): spte %p %llx %lld\n", spte, *spte, gfn);
 668                 if (is_writeble_pte(*spte)) {
 669                         rmap_remove(kvm, spte);
 670                         --kvm->stat.lpages;
 671                         set_shadow_pte(spte, shadow_trap_nonpresent_pte);
 672                         spte = NULL;
 673                         write_protected = 1;
 674                 }
 675                 spte = rmap_next(kvm, rmapp, spte);
 676         }
 677
 678         return write_protected;
 679 }
 680
 681 static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp)
 682 {
 683         u64 *spte;
 684         int need_tlb_flush = 0;
 685
 686         while ((spte = rmap_next(kvm, rmapp, NULL))) {
 687                 BUG_ON(!(*spte & PT_PRESENT_MASK));
 688                 rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", spte, *spte);
 689                 rmap_remove(kvm, spte);
 690                 set_shadow_pte(spte, shadow_trap_nonpresent_pte);
 691                 need_tlb_flush = 1;
 692         }
 693         return need_tlb_flush;
 694 }
 695
 696 static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
 697                           int (*handler)(struct kvm *kvm, unsigned long *rmapp))
 698 {
 699         int i;
 700         int retval = 0;
 701
 702         /*
 703          * If mmap_sem isn't taken, we can look the memslots with only
 704          * the mmu_lock by skipping over the slots with userspace_addr == 0.
 705          */
 706         for (i = 0; i < kvm->nmemslots; i++) {
 707                 struct kvm_memory_slot *memslot = &kvm->memslots[i];
 708                 unsigned long start = memslot->userspace_addr;
 709                 unsigned long end;
 710
 711                 /* mmu_lock protects userspace_addr */
 712                 if (!start)
 713                         continue;
 714
 715                 end = start + (memslot->npages << PAGE_SHIFT);
 716                 if (hva >= start && hva < end) {
 717                         gfn_t gfn_offset = (hva - start) >> PAGE_SHIFT;
 718                         retval |= handler(kvm, &memslot->rmap[gfn_offset]);
 719                         retval |= handler(kvm,
 720                                           &memslot->lpage_info[
 721                                                   gfn_offset /
 722                                                   KVM_PAGES_PER_HPAGE].rmap_pde);
 723                 }
 724         }
 725
 726         return retval;
 727 }
 728
 729 int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
 730 {
 731         return kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
 732 }
 733
 734 static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp)
 735 {
 736         u64 *spte;
 737         int young = 0;
 738
 739         /* always return old for EPT */
 740         if (!shadow_accessed_mask)
 741                 return 0;
 742
 743         spte = rmap_next(kvm, rmapp, NULL);
 744         while (spte) {
 745                 int _young;
 746                 u64 _spte = *spte;
 747                 BUG_ON(!(_spte & PT_PRESENT_MASK));
 748                 _young = _spte & PT_ACCESSED_MASK;
 749                 if (_young) {
 750                         young = 1;
 751                         clear_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte);
 752                 }
 753                 spte = rmap_next(kvm, rmapp, spte);
 754         }
 755         return young;
 756 }
 757
 758 int kvm_age_hva(struct kvm *kvm, unsigned long hva)
 759 {
 760         return kvm_handle_hva(kvm, hva, kvm_age_rmapp);
 761 }
 762
 763 #ifdef MMU_DEBUG
 764 static int is_empty_shadow_page(u64 *spt)
 765 {
 766         u64 *pos;
 767         u64 *end;
 768
 769         for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
 770                 if (is_shadow_present_pte(*pos)) {
 771                         printk(KERN_ERR "%s: %p %llx\n", __func__,
 772                                pos, *pos);
 773                         return 0;
 774                 }
 775         return 1;
 776 }
 777 #endif
 778
 779 static void kvm_mmu_free_page(struct kvm *kvm, struct kvm_mmu_page *sp)
 780 {
 781         ASSERT(is_empty_shadow_page(sp->spt));
 782         list_del(&sp->link);
 783         __free_page(virt_to_page(sp->spt));
 784         __free_page(virt_to_page(sp->gfns));
 785         kfree(sp);
 786         ++kvm->arch.n_free_mmu_pages;
 787 }
 788
 789 static unsigned kvm_page_table_hashfn(gfn_t gfn)
 790 {
 791         return gfn & ((1 << KVM_MMU_HASH_SHIFT) - 1);
 792 }
 793
 794 static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
 795                                                u64 *parent_pte)
 796 {
 797         struct kvm_mmu_page *sp;
 798
 799         sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache, sizeof *sp);
 800         sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
 801         sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
 802         set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
 803         list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
 804         INIT_LIST_HEAD(&sp->oos_link);
 805         bitmap_zero(sp->slot_bitmap, KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS);
 806         sp->multimapped = 0;
 807         sp->parent_pte = parent_pte;
 808         --vcpu->kvm->arch.n_free_mmu_pages;
 809         return sp;
 810 }
 811
 812 static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
 813                                     struct kvm_mmu_page *sp, u64 *parent_pte)
 814 {
 815         struct kvm_pte_chain *pte_chain;
 816         struct hlist_node *node;
 817         int i;
 818
 819         if (!parent_pte)
 820                 return;
 821         if (!sp->multimapped) {
 822                 u64 *old = sp->parent_pte;
 823
 824                 if (!old) {
 825                         sp->parent_pte = parent_pte;
 826                         return;
 827                 }
 828                 sp->multimapped = 1;
 829                 pte_chain = mmu_alloc_pte_chain(vcpu);
 830                 INIT_HLIST_HEAD(&sp->parent_ptes);
 831                 hlist_add_head(&pte_chain->link, &sp->parent_ptes);
 832                 pte_chain->parent_ptes[0] = old;
 833         }
 834         hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link) {
 835                 if (pte_chain->parent_ptes[NR_PTE_CHAIN_ENTRIES-1])
 836                         continue;
 837                 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i)
 838                         if (!pte_chain->parent_ptes[i]) {
 839                                 pte_chain->parent_ptes[i] = parent_pte;
 840                                 return;
 841                         }
 842         }
 843         pte_chain = mmu_alloc_pte_chain(vcpu);
 844         BUG_ON(!pte_chain);
 845         hlist_add_head(&pte_chain->link, &sp->parent_ptes);
 846         pte_chain->parent_ptes[0] = parent_pte;
 847 }
 848
 849 static void mmu_page_remove_parent_pte(struct kvm_mmu_page *sp,
 850                                        u64 *parent_pte)
 851 {
 852         struct kvm_pte_chain *pte_chain;
 853         struct hlist_node *node;
 854         int i;
 855
 856         if (!sp->multimapped) {
 857                 BUG_ON(sp->parent_pte != parent_pte);
 858                 sp->parent_pte = NULL;
 859                 return;
 860         }
 861         hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
 862                 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
 863                         if (!pte_chain->parent_ptes[i])
 864                                 break;
 865                         if (pte_chain->parent_ptes[i] != parent_pte)
 866                                 continue;
 867                         while (i + 1 < NR_PTE_CHAIN_ENTRIES
 868                                 && pte_chain->parent_ptes[i + 1]) {
 869                                 pte_chain->parent_ptes[i]
 870                                         = pte_chain->parent_ptes[i + 1];
 871                                 ++i;
 872                         }
 873                         pte_chain->parent_ptes[i] = NULL;
 874                         if (i == 0) {
 875                                 hlist_del(&pte_chain->link);
 876                                 mmu_free_pte_chain(pte_chain);
 877                                 if (hlist_empty(&sp->parent_ptes)) {
 878                                         sp->multimapped = 0;
 879                                         sp->parent_pte = NULL;
 880                                 }
 881                         }
 882                         return;
 883                 }
 884         BUG();
 885 }
 886
 887
 888 static void mmu_parent_walk(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
 889                             mmu_parent_walk_fn fn)
 890 {
 891         struct kvm_pte_chain *pte_chain;
 892         struct hlist_node *node;
 893         struct kvm_mmu_page *parent_sp;
 894         int i;
 895
 896         if (!sp->multimapped && sp->parent_pte) {
 897                 parent_sp = page_header(__pa(sp->parent_pte));
 898                 fn(vcpu, parent_sp);
 899                 mmu_parent_walk(vcpu, parent_sp, fn);
 900                 return;
 901         }
 902         hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
 903                 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
 904                         if (!pte_chain->parent_ptes[i])
 905                                 break;
 906                         parent_sp = page_header(__pa(pte_chain->parent_ptes[i]));
 907                         fn(vcpu, parent_sp);
 908                         mmu_parent_walk(vcpu, parent_sp, fn);
 909                 }
 910 }
 911
 912 static void kvm_mmu_update_unsync_bitmap(u64 *spte)
 913 {
 914         unsigned int index;
 915         struct kvm_mmu_page *sp = page_header(__pa(spte));
 916
 917         index = spte - sp->spt;
 918         if (!__test_and_set_bit(index, sp->unsync_child_bitmap))
 919                 sp->unsync_children++;
 920         WARN_ON(!sp->unsync_children);
 921 }
 922
 923 static void kvm_mmu_update_parents_unsync(struct kvm_mmu_page *sp)
 924 {
 925         struct kvm_pte_chain *pte_chain;
 926         struct hlist_node *node;
 927         int i;
 928
 929         if (!sp->parent_pte)
 930                 return;
 931
 932         if (!sp->multimapped) {
 933                 kvm_mmu_update_unsync_bitmap(sp->parent_pte);
 934                 return;
 935         }
 936
 937         hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
 938                 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
 939                         if (!pte_chain->parent_ptes[i])
 940                                 break;
 941                         kvm_mmu_update_unsync_bitmap(pte_chain->parent_ptes[i]);
 942                 }
 943 }
 944
 945 static int unsync_walk_fn(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
 946 {
 947         kvm_mmu_update_parents_unsync(sp);
 948         return 1;
 949 }
 950
 951 static void kvm_mmu_mark_parents_unsync(struct kvm_vcpu *vcpu,
 952                                         struct kvm_mmu_page *sp)
 953 {
 954         mmu_parent_walk(vcpu, sp, unsync_walk_fn);
 955         kvm_mmu_update_parents_unsync(sp);
 956 }
 957
 958 static void nonpaging_prefetch_page(struct kvm_vcpu *vcpu,
 959                                     struct kvm_mmu_page *sp)
 960 {
 961         int i;
 962
 963         for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
 964                 sp->spt[i] = shadow_trap_nonpresent_pte;
 965 }
 966
 967 static int nonpaging_sync_page(struct kvm_vcpu *vcpu,
 968                                struct kvm_mmu_page *sp)
 969 {
 970         return 1;
 971 }
 972
 973 static void nonpaging_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
 974 {
 975 }
 976
 977 #define KVM_PAGE_ARRAY_NR 16
 978
 979 struct kvm_mmu_pages {
 980         struct mmu_page_and_offset {
 981                 struct kvm_mmu_page *sp;
 982                 unsigned int idx;
 983         } page[KVM_PAGE_ARRAY_NR];
 984         unsigned int nr;
 985 };
 986
 987 #define for_each_unsync_children(bitmap, idx)           \
 988         for (idx = find_first_bit(bitmap, 512);         \
 989              idx < 512;                                 \
 990              idx = find_next_bit(bitmap, 512, idx+1))
 991
 992 static int mmu_pages_add(struct kvm_mmu_pages *pvec, struct kvm_mmu_page *sp,
 993                          int idx)
 994 {
 995         int i;
 996
 997         if (sp->unsync)
 998                 for (i=0; i < pvec->nr; i++)
 999                         if (pvec->page[i].sp == sp)
1000                                 return 0;
1001
1002         pvec->page[pvec->nr].sp = sp;
1003         pvec->page[pvec->nr].idx = idx;
1004         pvec->nr++;
1005         return (pvec->nr == KVM_PAGE_ARRAY_NR);
1006 }
1007
1008 static int __mmu_unsync_walk(struct kvm_mmu_page *sp,
1009                            struct kvm_mmu_pages *pvec)
1010 {
1011         int i, ret, nr_unsync_leaf = 0;
1012
1013         for_each_unsync_children(sp->unsync_child_bitmap, i) {
1014                 u64 ent = sp->spt[i];
1015
1016                 if (is_shadow_present_pte(ent) && !is_large_pte(ent)) {
1017                         struct kvm_mmu_page *child;
1018                         child = page_header(ent & PT64_BASE_ADDR_MASK);
1019
1020                         if (child->unsync_children) {
1021                                 if (mmu_pages_add(pvec, child, i))
1022                                         return -ENOSPC;
1023
1024                                 ret = __mmu_unsync_walk(child, pvec);
1025                                 if (!ret)
1026                                         __clear_bit(i, sp->unsync_child_bitmap);
1027                                 else if (ret > 0)
1028                                         nr_unsync_leaf += ret;
1029                                 else
1030                                         return ret;
1031                         }
1032
1033                         if (child->unsync) {
1034                                 nr_unsync_leaf++;
1035                                 if (mmu_pages_add(pvec, child, i))
1036                                         return -ENOSPC;
1037                         }
1038                 }
1039         }
1040
1041         if (find_first_bit(sp->unsync_child_bitmap, 512) == 512)
1042                 sp->unsync_children = 0;
1043
1044         return nr_unsync_leaf;
1045 }
1046
1047 static int mmu_unsync_walk(struct kvm_mmu_page *sp,
1048                            struct kvm_mmu_pages *pvec)
1049 {
1050         if (!sp->unsync_children)
1051                 return 0;
1052
1053         mmu_pages_add(pvec, sp, 0);
1054         return __mmu_unsync_walk(sp, pvec);
1055 }
1056
1057 static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm *kvm, gfn_t gfn)
1058 {
1059         unsigned index;
1060         struct hlist_head *bucket;
1061         struct kvm_mmu_page *sp;
1062         struct hlist_node *node;
1063
1064         pgprintk("%s: looking for gfn %lx\n", __func__, gfn);
1065         index = kvm_page_table_hashfn(gfn);
1066         bucket = &kvm->arch.mmu_page_hash[index];
1067         hlist_for_each_entry(sp, node, bucket, hash_link)
1068                 if (sp->gfn == gfn && !sp->role.direct
1069                     && !sp->role.invalid) {
1070                         pgprintk("%s: found role %x\n",
1071                                  __func__, sp->role.word);
1072                         return sp;
1073                 }
1074         return NULL;
1075 }
1076
1077 static void kvm_unlink_unsync_global(struct kvm *kvm, struct kvm_mmu_page *sp)
1078 {
1079         list_del(&sp->oos_link);
1080         --kvm->stat.mmu_unsync_global;
1081 }
1082
1083 static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
1084 {
1085         WARN_ON(!sp->unsync);
1086         sp->unsync = 0;
1087         if (sp->global)
1088                 kvm_unlink_unsync_global(kvm, sp);
1089         --kvm->stat.mmu_unsync;
1090 }
1091
1092 static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp);
1093
1094 static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
1095 {
1096         if (sp->role.glevels != vcpu->arch.mmu.root_level) {
1097                 kvm_mmu_zap_page(vcpu->kvm, sp);
1098                 return 1;
1099         }
1100
1101         if (rmap_write_protect(vcpu->kvm, sp->gfn))
1102                 kvm_flush_remote_tlbs(vcpu->kvm);
1103         kvm_unlink_unsync_page(vcpu->kvm, sp);
1104         if (vcpu->arch.mmu.sync_page(vcpu, sp)) {
1105                 kvm_mmu_zap_page(vcpu->kvm, sp);
1106                 return 1;
1107         }
1108
1109         kvm_mmu_flush_tlb(vcpu);
1110         return 0;
1111 }
1112
1113 struct mmu_page_path {
1114         struct kvm_mmu_page *parent[PT64_ROOT_LEVEL-1];
1115         unsigned int idx[PT64_ROOT_LEVEL-1];
1116 };
1117
1118 #define for_each_sp(pvec, sp, parents, i)                       \
1119                 for (i = mmu_pages_next(&pvec, &parents, -1),   \
1120                         sp = pvec.page[i].sp;                   \
1121                         i < pvec.nr && ({ sp = pvec.page[i].sp; 1;});   \
1122                         i = mmu_pages_next(&pvec, &parents, i))
1123
1124 static int mmu_pages_next(struct kvm_mmu_pages *pvec,
1125                           struct mmu_page_path *parents,
1126                           int i)
1127 {
1128         int n;
1129
1130         for (n = i+1; n < pvec->nr; n++) {
1131                 struct kvm_mmu_page *sp = pvec->page[n].sp;
1132
1133                 if (sp->role.level == PT_PAGE_TABLE_LEVEL) {
1134                         parents->idx[0] = pvec->page[n].idx;
1135                         return n;
1136                 }
1137
1138                 parents->parent[sp->role.level-2] = sp;
1139                 parents->idx[sp->role.level-1] = pvec->page[n].idx;
1140         }
1141
1142         return n;
1143 }
1144
1145 static void mmu_pages_clear_parents(struct mmu_page_path *parents)
1146 {
1147         struct kvm_mmu_page *sp;
1148         unsigned int level = 0;
1149
1150         do {
1151                 unsigned int idx = parents->idx[level];
1152
1153                 sp = parents->parent[level];
1154                 if (!sp)
1155                         return;
1156
1157                 --sp->unsync_children;
1158                 WARN_ON((int)sp->unsync_children < 0);
1159                 __clear_bit(idx, sp->unsync_child_bitmap);
1160                 level++;
1161         } while (level < PT64_ROOT_LEVEL-1 && !sp->unsync_children);
1162 }
1163
1164 static void kvm_mmu_pages_init(struct kvm_mmu_page *parent,
1165                                struct mmu_page_path *parents,
1166                                struct kvm_mmu_pages *pvec)
1167 {
1168         parents->parent[parent->role.level-1] = NULL;
1169         pvec->nr = 0;
1170 }
1171
1172 static void mmu_sync_children(struct kvm_vcpu *vcpu,
1173                               struct kvm_mmu_page *parent)
1174 {
1175         int i;
1176         struct kvm_mmu_page *sp;
1177         struct mmu_page_path parents;
1178         struct kvm_mmu_pages pages;
1179
1180         kvm_mmu_pages_init(parent, &parents, &pages);
1181         while (mmu_unsync_walk(parent, &pages)) {
1182                 int protected = 0;
1183
1184                 for_each_sp(pages, sp, parents, i)
1185                         protected |= rmap_write_protect(vcpu->kvm, sp->gfn);
1186
1187                 if (protected)
1188                         kvm_flush_remote_tlbs(vcpu->kvm);
1189
1190                 for_each_sp(pages, sp, parents, i) {
1191                         kvm_sync_page(vcpu, sp);
1192                         mmu_pages_clear_parents(&parents);
1193                 }
1194                 cond_resched_lock(&vcpu->kvm->mmu_lock);
1195                 kvm_mmu_pages_init(parent, &parents, &pages);
1196         }
1197 }
1198
1199 static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
1200                                              gfn_t gfn,
1201                                              gva_t gaddr,
1202                                              unsigned level,
1203                                              int direct,
1204                                              unsigned access,
1205                                              u64 *parent_pte)
1206 {
1207         union kvm_mmu_page_role role;
1208         unsigned index;
1209         unsigned quadrant;
1210         struct hlist_head *bucket;
1211         struct kvm_mmu_page *sp;
1212         struct hlist_node *node, *tmp;
1213
1214         role = vcpu->arch.mmu.base_role;
1215         role.level = level;
1216         role.direct = direct;
1217         role.access = access;
1218         if (vcpu->arch.mmu.root_level <= PT32_ROOT_LEVEL) {
1219                 quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
1220                 quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
1221                 role.quadrant = quadrant;
1222         }
1223         pgprintk("%s: looking gfn %lx role %x\n", __func__,
1224                  gfn, role.word);
1225         index = kvm_page_table_hashfn(gfn);
1226         bucket = &vcpu->kvm->arch.mmu_page_hash[index];
1227         hlist_for_each_entry_safe(sp, node, tmp, bucket, hash_link)
1228                 if (sp->gfn == gfn) {
1229                         if (sp->unsync)
1230                                 if (kvm_sync_page(vcpu, sp))
1231                                         continue;
1232
1233                         if (sp->role.word != role.word)
1234                                 continue;
1235
1236                         mmu_page_add_parent_pte(vcpu, sp, parent_pte);
1237                         if (sp->unsync_children) {
1238                                 set_bit(KVM_REQ_MMU_SYNC, &vcpu->requests);
1239                                 kvm_mmu_mark_parents_unsync(vcpu, sp);
1240                         }
1241                         pgprintk("%s: found\n", __func__);
1242                         return sp;
1243                 }
1244         ++vcpu->kvm->stat.mmu_cache_miss;
1245         sp = kvm_mmu_alloc_page(vcpu, parent_pte);
1246         if (!sp)
1247                 return sp;
1248         pgprintk("%s: adding gfn %lx role %x\n", __func__, gfn, role.word);
1249         sp->gfn = gfn;
1250         sp->role = role;
1251         sp->global = 0;
1252         hlist_add_head(&sp->hash_link, bucket);
1253         if (!direct) {
1254                 if (rmap_write_protect(vcpu->kvm, gfn))
1255                         kvm_flush_remote_tlbs(vcpu->kvm);
1256                 account_shadowed(vcpu->kvm, gfn);
1257         }
1258         if (shadow_trap_nonpresent_pte != shadow_notrap_nonpresent_pte)
1259                 vcpu->arch.mmu.prefetch_page(vcpu, sp);
1260         else
1261                 nonpaging_prefetch_page(vcpu, sp);
1262         return sp;
1263 }
1264
1265 static void shadow_walk_init(struct kvm_shadow_walk_iterator *iterator,
1266                              struct kvm_vcpu *vcpu, u64 addr)
1267 {
1268         iterator->addr = addr;
1269         iterator->shadow_addr = vcpu->arch.mmu.root_hpa;
1270         iterator->level = vcpu->arch.mmu.shadow_root_level;
1271         if (iterator->level == PT32E_ROOT_LEVEL) {
1272                 iterator->shadow_addr
1273                         = vcpu->arch.mmu.pae_root[(addr >> 30) & 3];
1274                 iterator->shadow_addr &= PT64_BASE_ADDR_MASK;
1275                 --iterator->level;
1276                 if (!iterator->shadow_addr)
1277                         iterator->level = 0;
1278         }
1279 }
1280
1281 static bool shadow_walk_okay(struct kvm_shadow_walk_iterator *iterator)
1282 {
1283         if (iterator->level < PT_PAGE_TABLE_LEVEL)
1284                 return false;
1285         iterator->index = SHADOW_PT_INDEX(iterator->addr, iterator->level);
1286         iterator->sptep = ((u64 *)__va(iterator->shadow_addr)) + iterator->index;
1287         return true;
1288 }
1289
1290 static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator)
1291 {
1292         iterator->shadow_addr = *iterator->sptep & PT64_BASE_ADDR_MASK;
1293         --iterator->level;
1294 }
1295
1296 static void kvm_mmu_page_unlink_children(struct kvm *kvm,
1297                                          struct kvm_mmu_page *sp)
1298 {
1299         unsigned i;
1300         u64 *pt;
1301         u64 ent;
1302
1303         pt = sp->spt;
1304
1305         if (sp->role.level == PT_PAGE_TABLE_LEVEL) {
1306                 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
1307                         if (is_shadow_present_pte(pt[i]))
1308                                 rmap_remove(kvm, &pt[i]);
1309                         pt[i] = shadow_trap_nonpresent_pte;
1310                 }
1311                 return;
1312         }
1313
1314         for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
1315                 ent = pt[i];
1316
1317                 if (is_shadow_present_pte(ent)) {
1318                         if (!is_large_pte(ent)) {
1319                                 ent &= PT64_BASE_ADDR_MASK;
1320                                 mmu_page_remove_parent_pte(page_header(ent),
1321                                                            &pt[i]);
1322                         } else {
1323                                 --kvm->stat.lpages;
1324                                 rmap_remove(kvm, &pt[i]);
1325                         }
1326                 }
1327                 pt[i] = shadow_trap_nonpresent_pte;
1328         }
1329 }
1330
1331 static void kvm_mmu_put_page(struct kvm_mmu_page *sp, u64 *parent_pte)
1332 {
1333         mmu_page_remove_parent_pte(sp, parent_pte);
1334 }
1335
1336 static void kvm_mmu_reset_last_pte_updated(struct kvm *kvm)
1337 {
1338         int i;
1339
1340         for (i = 0; i < KVM_MAX_VCPUS; ++i)
1341                 if (kvm->vcpus[i])
1342                         kvm->vcpus[i]->arch.last_pte_updated = NULL;
1343 }
1344
1345 static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp)
1346 {
1347         u64 *parent_pte;
1348
1349         while (sp->multimapped || sp->parent_pte) {
1350                 if (!sp->multimapped)
1351                         parent_pte = sp->parent_pte;
1352                 else {
1353                         struct kvm_pte_chain *chain;
1354
1355                         chain = container_of(sp->parent_ptes.first,
1356                                              struct kvm_pte_chain, link);
1357                         parent_pte = chain->parent_ptes[0];
1358                 }
1359                 BUG_ON(!parent_pte);
1360                 kvm_mmu_put_page(sp, parent_pte);
1361                 set_shadow_pte(parent_pte, shadow_trap_nonpresent_pte);
1362         }
1363 }
1364
1365 static int mmu_zap_unsync_children(struct kvm *kvm,
1366                                    struct kvm_mmu_page *parent)
1367 {
1368         int i, zapped = 0;
1369         struct mmu_page_path parents;
1370         struct kvm_mmu_pages pages;
1371
1372         if (parent->role.level == PT_PAGE_TABLE_LEVEL)
1373                 return 0;
1374
1375         kvm_mmu_pages_init(parent, &parents, &pages);
1376         while (mmu_unsync_walk(parent, &pages)) {
1377                 struct kvm_mmu_page *sp;
1378
1379                 for_each_sp(pages, sp, parents, i) {
1380                         kvm_mmu_zap_page(kvm, sp);
1381                         mmu_pages_clear_parents(&parents);
1382                 }
1383                 zapped += pages.nr;
1384                 kvm_mmu_pages_init(parent, &parents, &pages);
1385         }
1386
1387         return zapped;
1388 }
1389
1390 static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp)
1391 {
1392         int ret;
1393         ++kvm->stat.mmu_shadow_zapped;
1394         ret = mmu_zap_unsync_children(kvm, sp);
1395         kvm_mmu_page_unlink_children(kvm, sp);
1396         kvm_mmu_unlink_parents(kvm, sp);
1397         kvm_flush_remote_tlbs(kvm);
1398         if (!sp->role.invalid && !sp->role.direct)
1399                 unaccount_shadowed(kvm, sp->gfn);
1400         if (sp->unsync)
1401                 kvm_unlink_unsync_page(kvm, sp);
1402         if (!sp->root_count) {
1403                 hlist_del(&sp->hash_link);
1404                 kvm_mmu_free_page(kvm, sp);
1405         } else {
1406                 sp->role.invalid = 1;
1407                 list_move(&sp->link, &kvm->arch.active_mmu_pages);
1408                 kvm_reload_remote_mmus(kvm);
1409         }
1410         kvm_mmu_reset_last_pte_updated(kvm);
1411         return ret;
1412 }
1413
1414 /*
1415  * Changing the number of mmu pages allocated to the vm
1416  * Note: if kvm_nr_mmu_pages is too small, you will get dead lock
1417  */
1418 void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages)
1419 {
1420         /*
1421          * If we set the number of mmu pages to be smaller be than the
1422          * number of actived pages , we must to free some mmu pages before we
1423          * change the value
1424          */
1425
1426         if ((kvm->arch.n_alloc_mmu_pages - kvm->arch.n_free_mmu_pages) >
1427             kvm_nr_mmu_pages) {
1428                 int n_used_mmu_pages = kvm->arch.n_alloc_mmu_pages
1429                                        - kvm->arch.n_free_mmu_pages;
1430
1431                 while (n_used_mmu_pages > kvm_nr_mmu_pages) {
1432                         struct kvm_mmu_page *page;
1433
1434                         page = container_of(kvm->arch.active_mmu_pages.prev,
1435                                             struct kvm_mmu_page, link);
1436                         kvm_mmu_zap_page(kvm, page);
1437                         n_used_mmu_pages--;
1438                 }
1439                 kvm->arch.n_free_mmu_pages = 0;
1440         }
1441         else
1442                 kvm->arch.n_free_mmu_pages += kvm_nr_mmu_pages
1443                                          - kvm->arch.n_alloc_mmu_pages;
1444
1445         kvm->arch.n_alloc_mmu_pages = kvm_nr_mmu_pages;
1446 }
1447
1448 static int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
1449 {
1450         unsigned index;
1451         struct hlist_head *bucket;
1452         struct kvm_mmu_page *sp;
1453         struct hlist_node *node, *n;
1454         int r;
1455
1456         pgprintk("%s: looking for gfn %lx\n", __func__, gfn);
1457         r = 0;
1458         index = kvm_page_table_hashfn(gfn);
1459         bucket = &kvm->arch.mmu_page_hash[index];
1460         hlist_for_each_entry_safe(sp, node, n, bucket, hash_link)
1461                 if (sp->gfn == gfn && !sp->role.direct) {
1462                         pgprintk("%s: gfn %lx role %x\n", __func__, gfn,
1463                                  sp->role.word);
1464                         r = 1;
1465                         if (kvm_mmu_zap_page(kvm, sp))
1466                                 n = bucket->first;
1467                 }
1468         return r;
1469 }
1470
1471 static void mmu_unshadow(struct kvm *kvm, gfn_t gfn)
1472 {
1473         unsigned index;
1474         struct hlist_head *bucket;
1475         struct kvm_mmu_page *sp;
1476         struct hlist_node *node, *nn;
1477
1478         index = kvm_page_table_hashfn(gfn);
1479         bucket = &kvm->arch.mmu_page_hash[index];
1480         hlist_for_each_entry_safe(sp, node, nn, bucket, hash_link) {
1481                 if (sp->gfn == gfn && !sp->role.direct
1482                     && !sp->role.invalid) {
1483                         pgprintk("%s: zap %lx %x\n",
1484                                  __func__, gfn, sp->role.word);
1485                         kvm_mmu_zap_page(kvm, sp);
1486                 }
1487         }
1488 }
1489
1490 static void page_header_update_slot(struct kvm *kvm, void *pte, gfn_t gfn)
1491 {
1492         int slot = memslot_id(kvm, gfn_to_memslot(kvm, gfn));
1493         struct kvm_mmu_page *sp = page_header(__pa(pte));
1494
1495         __set_bit(slot, sp->slot_bitmap);
1496 }
1497
1498 static void mmu_convert_notrap(struct kvm_mmu_page *sp)
1499 {
1500         int i;
1501         u64 *pt = sp->spt;
1502
1503         if (shadow_trap_nonpresent_pte == shadow_notrap_nonpresent_pte)
1504                 return;
1505
1506         for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
1507                 if (pt[i] == shadow_notrap_nonpresent_pte)
1508                         set_shadow_pte(&pt[i], shadow_trap_nonpresent_pte);
1509         }
1510 }
1511
1512 struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva)
1513 {
1514         struct page *page;
1515
1516         gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva);
1517
1518         if (gpa == UNMAPPED_GVA)
1519                 return NULL;
1520
1521         page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);
1522
1523         return page;
1524 }
1525
1526 /*
1527  * The function is based on mtrr_type_lookup() in
1528  * arch/x86/kernel/cpu/mtrr/generic.c
1529  */
1530 static int get_mtrr_type(struct mtrr_state_type *mtrr_state,
1531                          u64 start, u64 end)
1532 {
1533         int i;
1534         u64 base, mask;
1535         u8 prev_match, curr_match;
1536         int num_var_ranges = KVM_NR_VAR_MTRR;
1537
1538         if (!mtrr_state->enabled)
1539                 return 0xFF;
1540
1541         /* Make end inclusive end, instead of exclusive */
1542         end--;
1543
1544         /* Look in fixed ranges. Just return the type as per start */
1545         if (mtrr_state->have_fixed && (start < 0x100000)) {
1546                 int idx;
1547
1548                 if (start < 0x80000) {
1549                         idx = 0;
1550                         idx += (start >> 16);
1551                         return mtrr_state->fixed_ranges[idx];
1552                 } else if (start < 0xC0000) {
1553                         idx = 1 * 8;
1554                         idx += ((start - 0x80000) >> 14);
1555                         return mtrr_state->fixed_ranges[idx];
1556                 } else if (start < 0x1000000) {
1557                         idx = 3 * 8;
1558                         idx += ((start - 0xC0000) >> 12);
1559                         return mtrr_state->fixed_ranges[idx];
1560                 }
1561         }
1562
1563         /*
1564          * Look in variable ranges
1565          * Look of multiple ranges matching this address and pick type
1566          * as per MTRR precedence
1567          */
1568         if (!(mtrr_state->enabled & 2))
1569                 return mtrr_state->def_type;
1570
1571         prev_match = 0xFF;
1572         for (i = 0; i < num_var_ranges; ++i) {
1573                 unsigned short start_state, end_state;
1574
1575                 if (!(mtrr_state->var_ranges[i].mask_lo & (1 << 11)))
1576                         continue;
1577
1578                 base = (((u64)mtrr_state->var_ranges[i].base_hi) << 32) +
1579                        (mtrr_state->var_ranges[i].base_lo & PAGE_MASK);
1580                 mask = (((u64)mtrr_state->var_ranges[i].mask_hi) << 32) +
1581                        (mtrr_state->var_ranges[i].mask_lo & PAGE_MASK);
1582
1583                 start_state = ((start & mask) == (base & mask));
1584                 end_state = ((end & mask) == (base & mask));
1585                 if (start_state != end_state)
1586                         return 0xFE;
1587
1588                 if ((start & mask) != (base & mask))
1589                         continue;
1590
1591                 curr_match = mtrr_state->var_ranges[i].base_lo & 0xff;
1592                 if (prev_match == 0xFF) {
1593                         prev_match = curr_match;
1594                         continue;
1595                 }
1596
1597                 if (prev_match == MTRR_TYPE_UNCACHABLE ||
1598                     curr_match == MTRR_TYPE_UNCACHABLE)
1599                         return MTRR_TYPE_UNCACHABLE;
1600
1601                 if ((prev_match == MTRR_TYPE_WRBACK &&
1602                      curr_match == MTRR_TYPE_WRTHROUGH) ||
1603                     (prev_match == MTRR_TYPE_WRTHROUGH &&
1604                      curr_match == MTRR_TYPE_WRBACK)) {
1605                         prev_match = MTRR_TYPE_WRTHROUGH;
1606                         curr_match = MTRR_TYPE_WRTHROUGH;
1607                 }
1608
1609                 if (prev_match != curr_match)
1610                         return MTRR_TYPE_UNCACHABLE;
1611         }
1612
1613         if (prev_match != 0xFF)
1614                 return prev_match;
1615
1616         return mtrr_state->def_type;
1617 }
1618
1619 static u8 get_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)
1620 {
1621         u8 mtrr;
1622
1623         mtrr = get_mtrr_type(&vcpu->arch.mtrr_state, gfn << PAGE_SHIFT,
1624                              (gfn << PAGE_SHIFT) + PAGE_SIZE);
1625         if (mtrr == 0xfe || mtrr == 0xff)
1626                 mtrr = MTRR_TYPE_WRBACK;
1627         return mtrr;
1628 }
1629
1630 static int kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
1631 {
1632         unsigned index;
1633         struct hlist_head *bucket;
1634         struct kvm_mmu_page *s;
1635         struct hlist_node *node, *n;
1636
1637         index = kvm_page_table_hashfn(sp->gfn);
1638         bucket = &vcpu->kvm->arch.mmu_page_hash[index];
1639         /* don't unsync if pagetable is shadowed with multiple roles */
1640         hlist_for_each_entry_safe(s, node, n, bucket, hash_link) {
1641                 if (s->gfn != sp->gfn || s->role.direct)
1642                         continue;
1643                 if (s->role.word != sp->role.word)
1644                         return 1;
1645         }
1646         ++vcpu->kvm->stat.mmu_unsync;
1647         sp->unsync = 1;
1648
1649         if (sp->global) {
1650                 list_add(&sp->oos_link, &vcpu->kvm->arch.oos_global_pages);
1651                 ++vcpu->kvm->stat.mmu_unsync_global;
1652         } else
1653                 kvm_mmu_mark_parents_unsync(vcpu, sp);
1654
1655         mmu_convert_notrap(sp);
1656         return 0;
1657 }
1658
1659 static int mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn,
1660                                   bool can_unsync)
1661 {
1662         struct kvm_mmu_page *shadow;
1663
1664         shadow = kvm_mmu_lookup_page(vcpu->kvm, gfn);
1665         if (shadow) {
1666                 if (shadow->role.level != PT_PAGE_TABLE_LEVEL)
1667                         return 1;
1668                 if (shadow->unsync)
1669                         return 0;
1670                 if (can_unsync && oos_shadow)
1671                         return kvm_unsync_page(vcpu, shadow);
1672                 return 1;
1673         }
1674         return 0;
1675 }
1676
1677 static int set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
1678                     unsigned pte_access, int user_fault,
1679                     int write_fault, int dirty, int largepage,
1680                     int global, gfn_t gfn, pfn_t pfn, bool speculative,
1681                     bool can_unsync)
1682 {
1683         u64 spte;
1684         int ret = 0;
1685         u64 mt_mask = shadow_mt_mask;
1686         struct kvm_mmu_page *sp = page_header(__pa(shadow_pte));
1687
1688         if (!global && sp->global) {
1689                 sp->global = 0;
1690                 if (sp->unsync) {
1691                         kvm_unlink_unsync_global(vcpu->kvm, sp);
1692                         kvm_mmu_mark_parents_unsync(vcpu, sp);
1693                 }
1694         }
1695
1696         /*
1697          * We don't set the accessed bit, since we sometimes want to see
1698          * whether the guest actually used the pte (in order to detect
1699          * demand paging).
1700          */
1701         spte = shadow_base_present_pte | shadow_dirty_mask;
1702         if (!speculative)
1703                 spte |= shadow_accessed_mask;
1704         if (!dirty)
1705                 pte_access &= ~ACC_WRITE_MASK;
1706         if (pte_access & ACC_EXEC_MASK)
1707                 spte |= shadow_x_mask;
1708         else
1709                 spte |= shadow_nx_mask;
1710         if (pte_access & ACC_USER_MASK)
1711                 spte |= shadow_user_mask;
1712         if (largepage)
1713                 spte |= PT_PAGE_SIZE_MASK;
1714         if (mt_mask) {
1715                 if (!kvm_is_mmio_pfn(pfn)) {
1716                         mt_mask = get_memory_type(vcpu, gfn) <<
1717                                 kvm_x86_ops->get_mt_mask_shift();
1718                         mt_mask |= VMX_EPT_IGMT_BIT;
1719                 } else
1720                         mt_mask = MTRR_TYPE_UNCACHABLE <<
1721                                 kvm_x86_ops->get_mt_mask_shift();
1722                 spte |= mt_mask;
1723         }
1724
1725         spte |= (u64)pfn << PAGE_SHIFT;
1726
1727         if ((pte_access & ACC_WRITE_MASK)
1728             || (write_fault && !is_write_protection(vcpu) && !user_fault)) {
1729
1730                 if (largepage && has_wrprotected_page(vcpu->kvm, gfn)) {
1731                         ret = 1;
1732                         spte = shadow_trap_nonpresent_pte;
1733                         goto set_pte;
1734                 }
1735
1736                 spte |= PT_WRITABLE_MASK;
1737
1738                 /*
1739                  * Optimization: for pte sync, if spte was writable the hash
1740                  * lookup is unnecessary (and expensive). Write protection
1741                  * is responsibility of mmu_get_page / kvm_sync_page.
1742                  * Same reasoning can be applied to dirty page accounting.
1743                  */
1744                 if (!can_unsync && is_writeble_pte(*shadow_pte))
1745                         goto set_pte;
1746
1747                 if (mmu_need_write_protect(vcpu, gfn, can_unsync)) {
1748                         pgprintk("%s: found shadow page for %lx, marking ro\n",
1749                                  __func__, gfn);
1750                         ret = 1;
1751                         pte_access &= ~ACC_WRITE_MASK;
1752                         if (is_writeble_pte(spte))
1753                                 spte &= ~PT_WRITABLE_MASK;
1754                 }
1755         }
1756
1757         if (pte_access & ACC_WRITE_MASK)
1758                 mark_page_dirty(vcpu->kvm, gfn);
1759
1760 set_pte:
1761         set_shadow_pte(shadow_pte, spte);
1762         return ret;
1763 }
1764
1765 static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
1766                          unsigned pt_access, unsigned pte_access,
1767                          int user_fault, int write_fault, int dirty,
1768                          int *ptwrite, int largepage, int global,
1769                          gfn_t gfn, pfn_t pfn, bool speculative)
1770 {
1771         int was_rmapped = 0;
1772         int was_writeble = is_writeble_pte(*shadow_pte);
1773
1774         pgprintk("%s: spte %llx access %x write_fault %d"
1775                  " user_fault %d gfn %lx\n",
1776                  __func__, *shadow_pte, pt_access,
1777                  write_fault, user_fault, gfn);
1778
1779         if (is_rmap_pte(*shadow_pte)) {
1780                 /*
1781                  * If we overwrite a PTE page pointer with a 2MB PMD, unlink
1782                  * the parent of the now unreachable PTE.
1783                  */
1784                 if (largepage && !is_large_pte(*shadow_pte)) {
1785                         struct kvm_mmu_page *child;
1786                         u64 pte = *shadow_pte;
1787
1788                         child = page_header(pte & PT64_BASE_ADDR_MASK);
1789                         mmu_page_remove_parent_pte(child, shadow_pte);
1790                 } else if (pfn != spte_to_pfn(*shadow_pte)) {
1791                         pgprintk("hfn old %lx new %lx\n",
1792                                  spte_to_pfn(*shadow_pte), pfn);
1793                         rmap_remove(vcpu->kvm, shadow_pte);
1794                 } else
1795                         was_rmapped = 1;
1796         }
1797         if (set_spte(vcpu, shadow_pte, pte_access, user_fault, write_fault,
1798                       dirty, largepage, global, gfn, pfn, speculative, true)) {
1799                 if (write_fault)
1800                         *ptwrite = 1;
1801                 kvm_x86_ops->tlb_flush(vcpu);
1802         }
1803
1804         pgprintk("%s: setting spte %llx\n", __func__, *shadow_pte);
1805         pgprintk("instantiating %s PTE (%s) at %ld (%llx) addr %p\n",
1806                  is_large_pte(*shadow_pte)? "2MB" : "4kB",
1807                  is_present_pte(*shadow_pte)?"RW":"R", gfn,
1808                  *shadow_pte, shadow_pte);
1809         if (!was_rmapped && is_large_pte(*shadow_pte))
1810                 ++vcpu->kvm->stat.lpages;
1811
1812         page_header_update_slot(vcpu->kvm, shadow_pte, gfn);
1813         if (!was_rmapped) {
1814                 rmap_add(vcpu, shadow_pte, gfn, largepage);
1815                 if (!is_rmap_pte(*shadow_pte))
1816                         kvm_release_pfn_clean(pfn);
1817         } else {
1818                 if (was_writeble)
1819                         kvm_release_pfn_dirty(pfn);
1820                 else
1821                         kvm_release_pfn_clean(pfn);
1822         }
1823         if (speculative) {
1824                 vcpu->arch.last_pte_updated = shadow_pte;
1825                 vcpu->arch.last_pte_gfn = gfn;
1826         }
1827 }
1828
1829 static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
1830 {
1831 }
1832
1833 static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
1834                         int largepage, gfn_t gfn, pfn_t pfn)
1835 {
1836         struct kvm_shadow_walk_iterator iterator;
1837         struct kvm_mmu_page *sp;
1838         int pt_write = 0;
1839         gfn_t pseudo_gfn;
1840
1841         for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) {
1842                 if (iterator.level == PT_PAGE_TABLE_LEVEL
1843                     || (largepage && iterator.level == PT_DIRECTORY_LEVEL)) {
1844                         mmu_set_spte(vcpu, iterator.sptep, ACC_ALL, ACC_ALL,
1845                                      0, write, 1, &pt_write,
1846                                      largepage, 0, gfn, pfn, false);
1847                         ++vcpu->stat.pf_fixed;
1848                         break;
1849                 }
1850
1851                 if (*iterator.sptep == shadow_trap_nonpresent_pte) {
1852                         pseudo_gfn = (iterator.addr & PT64_DIR_BASE_ADDR_MASK) >> PAGE_SHIFT;
1853                         sp = kvm_mmu_get_page(vcpu, pseudo_gfn, iterator.addr,
1854                                               iterator.level - 1,
1855                                               1, ACC_ALL, iterator.sptep);
1856                         if (!sp) {
1857                                 pgprintk("nonpaging_map: ENOMEM\n");
1858                                 kvm_release_pfn_clean(pfn);
1859                                 return -ENOMEM;
1860                         }
1861
1862                         set_shadow_pte(iterator.sptep,
1863                                        __pa(sp->spt)
1864                                        | PT_PRESENT_MASK | PT_WRITABLE_MASK
1865                                        | shadow_user_mask | shadow_x_mask);
1866                 }
1867         }
1868         return pt_write;
1869 }
1870
1871 static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
1872 {
1873         int r;
1874         int largepage = 0;
1875         pfn_t pfn;
1876         unsigned long mmu_seq;
1877
1878         if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
1879                 gfn &= ~(KVM_PAGES_PER_HPAGE-1);
1880                 largepage = 1;
1881         }
1882
1883         mmu_seq = vcpu->kvm->mmu_notifier_seq;
1884         smp_rmb();
1885         pfn = gfn_to_pfn(vcpu->kvm, gfn);
1886
1887         /* mmio */
1888         if (is_error_pfn(pfn)) {
1889                 kvm_release_pfn_clean(pfn);
1890                 return 1;
1891         }
1892
1893         spin_lock(&vcpu->kvm->mmu_lock);
1894         if (mmu_notifier_retry(vcpu, mmu_seq))
1895                 goto out_unlock;
1896         kvm_mmu_free_some_pages(vcpu);
1897         r = __direct_map(vcpu, v, write, largepage, gfn, pfn);
1898         spin_unlock(&vcpu->kvm->mmu_lock);
1899
1900
1901         return r;
1902
1903 out_unlock:
1904         spin_unlock(&vcpu->kvm->mmu_lock);
1905         kvm_release_pfn_clean(pfn);
1906         return 0;
1907 }
1908
1909
1910 static void mmu_free_roots(struct kvm_vcpu *vcpu)
1911 {
1912         int i;
1913         struct kvm_mmu_page *sp;
1914
1915         if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
1916                 return;
1917         spin_lock(&vcpu->kvm->mmu_lock);
1918         if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
1919                 hpa_t root = vcpu->arch.mmu.root_hpa;
1920
1921                 sp = page_header(root);
1922                 --sp->root_count;
1923                 if (!sp->root_count && sp->role.invalid)
1924                         kvm_mmu_zap_page(vcpu->kvm, sp);
1925                 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
1926                 spin_unlock(&vcpu->kvm->mmu_lock);
1927                 return;
1928         }
1929         for (i = 0; i < 4; ++i) {
1930                 hpa_t root = vcpu->arch.mmu.pae_root[i];
1931
1932                 if (root) {
1933                         root &= PT64_BASE_ADDR_MASK;
1934                         sp = page_header(root);
1935                         --sp->root_count;
1936                         if (!sp->root_count && sp->role.invalid)
1937                                 kvm_mmu_zap_page(vcpu->kvm, sp);
1938                 }
1939                 vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
1940         }
1941         spin_unlock(&vcpu->kvm->mmu_lock);
1942         vcpu->arch.mmu.root_hpa = INVALID_PAGE;
1943 }
1944
1945 static void mmu_alloc_roots(struct kvm_vcpu *vcpu)
1946 {
1947         int i;
1948         gfn_t root_gfn;
1949         struct kvm_mmu_page *sp;
1950         int direct = 0;
1951
1952         root_gfn = vcpu->arch.cr3 >> PAGE_SHIFT;
1953
1954         if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
1955                 hpa_t root = vcpu->arch.mmu.root_hpa;
1956
1957                 ASSERT(!VALID_PAGE(root));
1958                 if (tdp_enabled)
1959                         direct = 1;
1960                 sp = kvm_mmu_get_page(vcpu, root_gfn, 0,
1961                                       PT64_ROOT_LEVEL, direct,
1962                                       ACC_ALL, NULL);
1963                 root = __pa(sp->spt);
1964                 ++sp->root_count;
1965                 vcpu->arch.mmu.root_hpa = root;
1966                 return;
1967         }
1968         direct = !is_paging(vcpu);
1969         if (tdp_enabled)
1970                 direct = 1;
1971         for (i = 0; i < 4; ++i) {
1972                 hpa_t root = vcpu->arch.mmu.pae_root[i];
1973
1974                 ASSERT(!VALID_PAGE(root));
1975                 if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
1976                         if (!is_present_pte(vcpu->arch.pdptrs[i])) {
1977                                 vcpu->arch.mmu.pae_root[i] = 0;
1978                                 continue;
1979                         }
1980                         root_gfn = vcpu->arch.pdptrs[i] >> PAGE_SHIFT;
1981                 } else if (vcpu->arch.mmu.root_level == 0)
1982                         root_gfn = 0;
1983                 sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
1984                                       PT32_ROOT_LEVEL, direct,
1985                                       ACC_ALL, NULL);
1986                 root = __pa(sp->spt);
1987                 ++sp->root_count;
1988                 vcpu->arch.mmu.pae_root[i] = root | PT_PRESENT_MASK;
1989         }
1990         vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
1991 }
1992
1993 static void mmu_sync_roots(struct kvm_vcpu *vcpu)
1994 {
1995         int i;
1996         struct kvm_mmu_page *sp;
1997
1998         if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
1999                 return;
2000         if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
2001                 hpa_t root = vcpu->arch.mmu.root_hpa;
2002                 sp = page_header(root);
2003                 mmu_sync_children(vcpu, sp);
2004                 return;
2005         }
2006         for (i = 0; i < 4; ++i) {
2007                 hpa_t root = vcpu->arch.mmu.pae_root[i];
2008
2009                 if (root) {
2010                         root &= PT64_BASE_ADDR_MASK;
2011                         sp = page_header(root);
2012                         mmu_sync_children(vcpu, sp);
2013                 }
2014         }
2015 }
2016
2017 static void mmu_sync_global(struct kvm_vcpu *vcpu)
2018 {
2019         struct kvm *kvm = vcpu->kvm;
2020         struct kvm_mmu_page *sp, *n;
2021
2022         list_for_each_entry_safe(sp, n, &kvm->arch.oos_global_pages, oos_link)
2023                 kvm_sync_page(vcpu, sp);
2024 }
2025
2026 void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
2027 {
2028         spin_lock(&vcpu->kvm->mmu_lock);
2029         mmu_sync_roots(vcpu);
2030         spin_unlock(&vcpu->kvm->mmu_lock);
2031 }
2032
2033 void kvm_mmu_sync_global(struct kvm_vcpu *vcpu)
2034 {
2035         spin_lock(&vcpu->kvm->mmu_lock);
2036         mmu_sync_global(vcpu);
2037         spin_unlock(&vcpu->kvm->mmu_lock);
2038 }
2039
2040 static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr)
2041 {
2042         return vaddr;
2043 }
2044
2045 static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
2046                                 u32 error_code)
2047 {
2048         gfn_t gfn;
2049         int r;
2050
2051         pgprintk("%s: gva %lx error %x\n", __func__, gva, error_code);
2052         r = mmu_topup_memory_caches(vcpu);
2053         if (r)
2054                 return r;
2055
2056         ASSERT(vcpu);
2057         ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
2058
2059         gfn = gva >> PAGE_SHIFT;
2060
2061         return nonpaging_map(vcpu, gva & PAGE_MASK,
2062                              error_code & PFERR_WRITE_MASK, gfn);
2063 }
2064
2065 static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
2066                                 u32 error_code)
2067 {
2068         pfn_t pfn;
2069         int r;
2070         int largepage = 0;
2071         gfn_t gfn = gpa >> PAGE_SHIFT;
2072         unsigned long mmu_seq;
2073
2074         ASSERT(vcpu);
2075         ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
2076
2077         r = mmu_topup_memory_caches(vcpu);
2078         if (r)
2079                 return r;
2080
2081         if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
2082                 gfn &= ~(KVM_PAGES_PER_HPAGE-1);
2083                 largepage = 1;
2084         }
2085         mmu_seq = vcpu->kvm->mmu_notifier_seq;
2086         smp_rmb();
2087         pfn = gfn_to_pfn(vcpu->kvm, gfn);
2088         if (is_error_pfn(pfn)) {
2089                 kvm_release_pfn_clean(pfn);
2090                 return 1;
2091         }
2092         spin_lock(&vcpu->kvm->mmu_lock);
2093         if (mmu_notifier_retry(vcpu, mmu_seq))
2094                 goto out_unlock;
2095         kvm_mmu_free_some_pages(vcpu);
2096         r = __direct_map(vcpu, gpa, error_code & PFERR_WRITE_MASK,
2097                          largepage, gfn, pfn);
2098         spin_unlock(&vcpu->kvm->mmu_lock);
2099
2100         return r;
2101
2102 out_unlock:
2103         spin_unlock(&vcpu->kvm->mmu_lock);
2104         kvm_release_pfn_clean(pfn);
2105         return 0;
2106 }
2107
2108 static void nonpaging_free(struct kvm_vcpu *vcpu)
2109 {
2110         mmu_free_roots(vcpu);
2111 }
2112
2113 static int nonpaging_init_context(struct kvm_vcpu *vcpu)
2114 {
2115         struct kvm_mmu *context = &vcpu->arch.mmu;
2116
2117         context->new_cr3 = nonpaging_new_cr3;
2118         context->page_fault = nonpaging_page_fault;
2119         context->gva_to_gpa = nonpaging_gva_to_gpa;
2120         context->free = nonpaging_free;
2121         context->prefetch_page = nonpaging_prefetch_page;
2122         context->sync_page = nonpaging_sync_page;
2123         context->invlpg = nonpaging_invlpg;
2124         context->root_level = 0;
2125         context->shadow_root_level = PT32E_ROOT_LEVEL;
2126         context->root_hpa = INVALID_PAGE;
2127         return 0;
2128 }
2129
2130 void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
2131 {
2132         ++vcpu->stat.tlb_flush;
2133         kvm_x86_ops->tlb_flush(vcpu);
2134 }
2135
2136 static void paging_new_cr3(struct kvm_vcpu *vcpu)
2137 {
2138         pgprintk("%s: cr3 %lx\n", __func__, vcpu->arch.cr3);
2139         mmu_free_roots(vcpu);
2140 }
2141
2142 static void inject_page_fault(struct kvm_vcpu *vcpu,
2143                               u64 addr,
2144                               u32 err_code)
2145 {
2146         kvm_inject_page_fault(vcpu, addr, err_code);
2147 }
2148
2149 static void paging_free(struct kvm_vcpu *vcpu)
2150 {
2151         nonpaging_free(vcpu);
2152 }
2153
2154 #define PTTYPE 64
2155 #include "paging_tmpl.h"
2156 #undef PTTYPE
2157
2158 #define PTTYPE 32
2159 #include "paging_tmpl.h"
2160 #undef PTTYPE
2161
2162 static int paging64_init_context_common(struct kvm_vcpu *vcpu, int level)
2163 {
2164         struct kvm_mmu *context = &vcpu->arch.mmu;
2165
2166         ASSERT(is_pae(vcpu));
2167         context->new_cr3 = paging_new_cr3;
2168         context->page_fault = paging64_page_fault;
2169         context->gva_to_gpa = paging64_gva_to_gpa;
2170         context->prefetch_page = paging64_prefetch_page;
2171         context->sync_page = paging64_sync_page;
2172         context->invlpg = paging64_invlpg;
2173         context->free = paging_free;
2174         context->root_level = level;
2175         context->shadow_root_level = level;
2176         context->root_hpa = INVALID_PAGE;
2177         return 0;
2178 }
2179
2180 static int paging64_init_context(struct kvm_vcpu *vcpu)
2181 {
2182         return paging64_init_context_common(vcpu, PT64_ROOT_LEVEL);
2183 }
2184
2185 static int paging32_init_context(struct kvm_vcpu *vcpu)
2186 {
2187         struct kvm_mmu *context = &vcpu->arch.mmu;
2188
2189         context->new_cr3 = paging_new_cr3;
2190         context->page_fault = paging32_page_fault;
2191         context->gva_to_gpa = paging32_gva_to_gpa;
2192         context->free = paging_free;
2193         context->prefetch_page = paging32_prefetch_page;
2194         context->sync_page = paging32_sync_page;
2195         context->invlpg = paging32_invlpg;
2196         context->root_level = PT32_ROOT_LEVEL;
2197         context->shadow_root_level = PT32E_ROOT_LEVEL;
2198         context->root_hpa = INVALID_PAGE;
2199         return 0;
2200 }
2201
2202 static int paging32E_init_context(struct kvm_vcpu *vcpu)
2203 {
2204         return paging64_init_context_common(vcpu, PT32E_ROOT_LEVEL);
2205 }
2206
2207 static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
2208 {
2209         struct kvm_mmu *context = &vcpu->arch.mmu;
2210
2211         context->new_cr3 = nonpaging_new_cr3;
2212         context->page_fault = tdp_page_fault;
2213         context->free = nonpaging_free;
2214         context->prefetch_page = nonpaging_prefetch_page;
2215         context->sync_page = nonpaging_sync_page;
2216         context->invlpg = nonpaging_invlpg;
2217         context->shadow_root_level = kvm_x86_ops->get_tdp_level();
2218         context->root_hpa = INVALID_PAGE;
2219
2220         if (!is_paging(vcpu)) {
2221                 context->gva_to_gpa = nonpaging_gva_to_gpa;
2222                 context->root_level = 0;
2223         } else if (is_long_mode(vcpu)) {
2224                 context->gva_to_gpa = paging64_gva_to_gpa;
2225                 context->root_level = PT64_ROOT_LEVEL;
2226         } else if (is_pae(vcpu)) {
2227                 context->gva_to_gpa = paging64_gva_to_gpa;
2228                 context->root_level = PT32E_ROOT_LEVEL;
2229         } else {
2230                 context->gva_to_gpa = paging32_gva_to_gpa;
2231                 context->root_level = PT32_ROOT_LEVEL;
2232         }
2233
2234         return 0;
2235 }
2236
2237 static int init_kvm_softmmu(struct kvm_vcpu *vcpu)
2238 {
2239         int r;
2240
2241         ASSERT(vcpu);
2242         ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
2243
2244         if (!is_paging(vcpu))
2245                 r = nonpaging_init_context(vcpu);
2246         else if (is_long_mode(vcpu))
2247                 r = paging64_init_context(vcpu);
2248         else if (is_pae(vcpu))
2249                 r = paging32E_init_context(vcpu);
2250         else
2251                 r = paging32_init_context(vcpu);
2252
2253         vcpu->arch.mmu.base_role.glevels = vcpu->arch.mmu.root_level;
2254
2255         return r;
2256 }
2257
2258 static int init_kvm_mmu(struct kvm_vcpu *vcpu)
2259 {
2260         vcpu->arch.update_pte.pfn = bad_pfn;
2261
2262         if (tdp_enabled)
2263                 return init_kvm_tdp_mmu(vcpu);
2264         else
2265                 return init_kvm_softmmu(vcpu);
2266 }
2267
2268 static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
2269 {
2270         ASSERT(vcpu);
2271         if (VALID_PAGE(vcpu->arch.mmu.root_hpa)) {
2272                 vcpu->arch.mmu.free(vcpu);
2273                 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
2274         }
2275 }
2276
2277 int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
2278 {
2279         destroy_kvm_mmu(vcpu);
2280         return init_kvm_mmu(vcpu);
2281 }
2282 EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
2283
2284 int kvm_mmu_load(struct kvm_vcpu *vcpu)
2285 {
2286         int r;
2287
2288         r = mmu_topup_memory_caches(vcpu);
2289         if (r)
2290                 goto out;
2291         spin_lock(&vcpu->kvm->mmu_lock);
2292         kvm_mmu_free_some_pages(vcpu);
2293         mmu_alloc_roots(vcpu);
2294         mmu_sync_roots(vcpu);
2295         spin_unlock(&vcpu->kvm->mmu_lock);
2296         kvm_x86_ops->set_cr3(vcpu, vcpu->arch.mmu.root_hpa);
2297         kvm_mmu_flush_tlb(vcpu);
2298 out:
2299         return r;
2300 }
2301 EXPORT_SYMBOL_GPL(kvm_mmu_load);
2302
2303 void kvm_mmu_unload(struct kvm_vcpu *vcpu)
2304 {
2305         mmu_free_roots(vcpu);
2306 }
2307
2308 static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
2309                                   struct kvm_mmu_page *sp,
2310                                   u64 *spte)
2311 {
2312         u64 pte;
2313         struct kvm_mmu_page *child;
2314
2315         pte = *spte;
2316         if (is_shadow_present_pte(pte)) {
2317                 if (sp->role.level == PT_PAGE_TABLE_LEVEL ||
2318                     is_large_pte(pte))
2319                         rmap_remove(vcpu->kvm, spte);
2320                 else {
2321                         child = page_header(pte & PT64_BASE_ADDR_MASK);
2322                         mmu_page_remove_parent_pte(child, spte);
2323                 }
2324         }
2325         set_shadow_pte(spte, shadow_trap_nonpresent_pte);
2326         if (is_large_pte(pte))
2327                 --vcpu->kvm->stat.lpages;
2328 }
2329
2330 static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
2331                                   struct kvm_mmu_page *sp,
2332                                   u64 *spte,
2333                                   const void *new)
2334 {
2335         if (sp->role.level != PT_PAGE_TABLE_LEVEL) {
2336                 if (!vcpu->arch.update_pte.largepage ||
2337                     sp->role.glevels == PT32_ROOT_LEVEL) {
2338                         ++vcpu->kvm->stat.mmu_pde_zapped;
2339                         return;
2340                 }
2341         }
2342
2343         ++vcpu->kvm->stat.mmu_pte_updated;
2344         if (sp->role.glevels == PT32_ROOT_LEVEL)
2345                 paging32_update_pte(vcpu, sp, spte, new);
2346         else
2347                 paging64_update_pte(vcpu, sp, spte, new);
2348 }
2349
2350 static bool need_remote_flush(u64 old, u64 new)
2351 {
2352         if (!is_shadow_present_pte(old))
2353                 return false;
2354         if (!is_shadow_present_pte(new))
2355                 return true;
2356         if ((old ^ new) & PT64_BASE_ADDR_MASK)
2357                 return true;
2358         old ^= PT64_NX_MASK;
2359         new ^= PT64_NX_MASK;
2360         return (old & ~new & PT64_PERM_MASK) != 0;
2361 }
2362
2363 static void mmu_pte_write_flush_tlb(struct kvm_vcpu *vcpu, u64 old, u64 new)
2364 {
2365         if (need_remote_flush(old, new))
2366                 kvm_flush_remote_tlbs(vcpu->kvm);
2367         else
2368                 kvm_mmu_flush_tlb(vcpu);
2369 }
2370
2371 static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu)
2372 {
2373         u64 *spte = vcpu->arch.last_pte_updated;
2374
2375         return !!(spte && (*spte & shadow_accessed_mask));
2376 }
2377
2378 static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
2379                                           const u8 *new, int bytes)
2380 {
2381         gfn_t gfn;
2382         int r;
2383         u64 gpte = 0;
2384         pfn_t pfn;
2385
2386         vcpu->arch.update_pte.largepage = 0;
2387
2388         if (bytes != 4 && bytes != 8)
2389                 return;
2390
2391         /*
2392          * Assume that the pte write on a page table of the same type
2393          * as the current vcpu paging mode.  This is nearly always true
2394          * (might be false while changing modes).  Note it is verified later
2395          * by update_pte().
2396          */
2397         if (is_pae(vcpu)) {
2398                 /* Handle a 32-bit guest writing two halves of a 64-bit gpte */
2399                 if ((bytes == 4) && (gpa % 4 == 0)) {
2400                         r = kvm_read_guest(vcpu->kvm, gpa & ~(u64)7, &gpte, 8);
2401                         if (r)
2402                                 return;
2403                         memcpy((void *)&gpte + (gpa % 8), new, 4);
2404                 } else if ((bytes == 8) && (gpa % 8 == 0)) {
2405                         memcpy((void *)&gpte, new, 8);
2406                 }
2407         } else {
2408                 if ((bytes == 4) && (gpa % 4 == 0))
2409                         memcpy((void *)&gpte, new, 4);
2410         }
2411         if (!is_present_pte(gpte))
2412                 return;
2413         gfn = (gpte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
2414
2415         if (is_large_pte(gpte) && is_largepage_backed(vcpu, gfn)) {
2416                 gfn &= ~(KVM_PAGES_PER_HPAGE-1);
2417                 vcpu->arch.update_pte.largepage = 1;
2418         }
2419         vcpu->arch.update_pte.mmu_seq = vcpu->kvm->mmu_notifier_seq;
2420         smp_rmb();
2421         pfn = gfn_to_pfn(vcpu->kvm, gfn);
2422
2423         if (is_error_pfn(pfn)) {
2424                 kvm_release_pfn_clean(pfn);
2425                 return;
2426         }
2427         vcpu->arch.update_pte.gfn = gfn;
2428         vcpu->arch.update_pte.pfn = pfn;
2429 }
2430
2431 static void kvm_mmu_access_page(struct kvm_vcpu *vcpu, gfn_t gfn)
2432 {
2433         u64 *spte = vcpu->arch.last_pte_updated;
2434
2435         if (spte
2436             && vcpu->arch.last_pte_gfn == gfn
2437             && shadow_accessed_mask
2438             && !(*spte & shadow_accessed_mask)
2439             && is_shadow_present_pte(*spte))
2440                 set_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte);
2441 }
2442
2443 void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
2444                        const u8 *new, int bytes,
2445                        bool guest_initiated)
2446 {
2447         gfn_t gfn = gpa >> PAGE_SHIFT;
2448         struct kvm_mmu_page *sp;
2449         struct hlist_node *node, *n;
2450         struct hlist_head *bucket;
2451         unsigned index;
2452         u64 entry, gentry;
2453         u64 *spte;
2454         unsigned offset = offset_in_page(gpa);
2455         unsigned pte_size;
2456         unsigned page_offset;
2457         unsigned misaligned;
2458         unsigned quadrant;
2459         int level;
2460         int flooded = 0;
2461         int npte;
2462         int r;
2463
2464         pgprintk("%s: gpa %llx bytes %d\n", __func__, gpa, bytes);
2465         mmu_guess_page_from_pte_write(vcpu, gpa, new, bytes);
2466         spin_lock(&vcpu->kvm->mmu_lock);
2467         kvm_mmu_access_page(vcpu, gfn);
2468         kvm_mmu_free_some_pages(vcpu);
2469         ++vcpu->kvm->stat.mmu_pte_write;
2470         kvm_mmu_audit(vcpu, "pre pte write");
2471         if (guest_initiated) {
2472                 if (gfn == vcpu->arch.last_pt_write_gfn
2473                     && !last_updated_pte_accessed(vcpu)) {
2474                         ++vcpu->arch.last_pt_write_count;
2475                         if (vcpu->arch.last_pt_write_count >= 3)
2476                                 flooded = 1;
2477                 } else {
2478                         vcpu->arch.last_pt_write_gfn = gfn;
2479                         vcpu->arch.last_pt_write_count = 1;
2480                         vcpu->arch.last_pte_updated = NULL;
2481                 }
2482         }
2483         index = kvm_page_table_hashfn(gfn);
2484         bucket = &vcpu->kvm->arch.mmu_page_hash[index];
2485         hlist_for_each_entry_safe(sp, node, n, bucket, hash_link) {
2486                 if (sp->gfn != gfn || sp->role.direct || sp->role.invalid)
2487                         continue;
2488                 pte_size = sp->role.glevels == PT32_ROOT_LEVEL ? 4 : 8;
2489                 misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
2490                 misaligned |= bytes < 4;
2491                 if (misaligned || flooded) {
2492                         /*
2493                          * Misaligned accesses are too much trouble to fix
2494                          * up; also, they usually indicate a page is not used
2495                          * as a page table.
2496                          *
2497                          * If we're seeing too many writes to a page,
2498                          * it may no longer be a page table, or we may be
2499                          * forking, in which case it is better to unmap the
2500                          * page.
2501                          */
2502                         pgprintk("misaligned: gpa %llx bytes %d role %x\n",
2503                                  gpa, bytes, sp->role.word);
2504                         if (kvm_mmu_zap_page(vcpu->kvm, sp))
2505                                 n = bucket->first;
2506                         ++vcpu->kvm->stat.mmu_flooded;
2507                         continue;
2508                 }
2509                 page_offset = offset;
2510                 level = sp->role.level;
2511                 npte = 1;
2512                 if (sp->role.glevels == PT32_ROOT_LEVEL) {
2513                         page_offset <<= 1;      /* 32->64 */
2514                         /*
2515                          * A 32-bit pde maps 4MB while the shadow pdes map
2516                          * only 2MB.  So we need to double the offset again
2517                          * and zap two pdes instead of one.
2518                          */
2519                         if (level == PT32_ROOT_LEVEL) {
2520                                 page_offset &= ~7; /* kill rounding error */
2521                                 page_offset <<= 1;
2522                                 npte = 2;
2523                         }
2524                         quadrant = page_offset >> PAGE_SHIFT;
2525                         page_offset &= ~PAGE_MASK;
2526                         if (quadrant != sp->role.quadrant)
2527                                 continue;
2528                 }
2529                 spte = &sp->spt[page_offset / sizeof(*spte)];
2530                 if ((gpa & (pte_size - 1)) || (bytes < pte_size)) {
2531                         gentry = 0;
2532                         r = kvm_read_guest_atomic(vcpu->kvm,
2533                                                   gpa & ~(u64)(pte_size - 1),
2534                                                   &gentry, pte_size);
2535                         new = (const void *)&gentry;
2536                         if (r < 0)
2537                                 new = NULL;
2538                 }
2539                 while (npte--) {
2540                         entry = *spte;
2541                         mmu_pte_write_zap_pte(vcpu, sp, spte);
2542                         if (new)
2543                                 mmu_pte_write_new_pte(vcpu, sp, spte, new);
2544                         mmu_pte_write_flush_tlb(vcpu, entry, *spte);
2545                         ++spte;
2546                 }
2547         }
2548         kvm_mmu_audit(vcpu, "post pte write");
2549         spin_unlock(&vcpu->kvm->mmu_lock);
2550         if (!is_error_pfn(vcpu->arch.update_pte.pfn)) {
2551                 kvm_release_pfn_clean(vcpu->arch.update_pte.pfn);
2552                 vcpu->arch.update_pte.pfn = bad_pfn;
2553         }
2554 }
2555
2556 int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
2557 {
2558         gpa_t gpa;
2559         int r;
2560
2561         gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva);
2562
2563         spin_lock(&vcpu->kvm->mmu_lock);
2564         r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
2565         spin_unlock(&vcpu->kvm->mmu_lock);
2566         return r;
2567 }
2568 EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page_virt);
2569
2570 void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
2571 {
2572         while (vcpu->kvm->arch.n_free_mmu_pages < KVM_REFILL_PAGES) {
2573                 struct kvm_mmu_page *sp;
2574
2575                 sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev,
2576                                   struct kvm_mmu_page, link);
2577                 kvm_mmu_zap_page(vcpu->kvm, sp);
2578                 ++vcpu->kvm->stat.mmu_recycled;
2579         }
2580 }
2581
2582 int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code)
2583 {
2584         int r;
2585         enum emulation_result er;
2586
2587         r = vcpu->arch.mmu.page_fault(vcpu, cr2, error_code);
2588         if (r < 0)
2589                 goto out;
2590
2591         if (!r) {
2592                 r = 1;
2593                 goto out;
2594         }
2595
2596         r = mmu_topup_memory_caches(vcpu);
2597         if (r)
2598                 goto out;
2599
2600         er = emulate_instruction(vcpu, vcpu->run, cr2, error_code, 0);
2601
2602         switch (er) {
2603         case EMULATE_DONE:
2604                 return 1;
2605         case EMULATE_DO_MMIO:
2606                 ++vcpu->stat.mmio_exits;
2607                 return 0;
2608         case EMULATE_FAIL:
2609                 kvm_report_emulation_failure(vcpu, "pagetable");
2610                 return 1;
2611         default:
2612                 BUG();
2613         }
2614 out:
2615         return r;
2616 }
2617 EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);
2618
2619 void kvm_mmu_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
2620 {
2621         vcpu->arch.mmu.invlpg(vcpu, gva);
2622         kvm_mmu_flush_tlb(vcpu);
2623         ++vcpu->stat.invlpg;
2624 }
2625 EXPORT_SYMBOL_GPL(kvm_mmu_invlpg);
2626
2627 void kvm_enable_tdp(void)
2628 {
2629         tdp_enabled = true;
2630 }
2631 EXPORT_SYMBOL_GPL(kvm_enable_tdp);
2632
2633 void kvm_disable_tdp(void)
2634 {
2635         tdp_enabled = false;
2636 }
2637 EXPORT_SYMBOL_GPL(kvm_disable_tdp);
2638
2639 static void free_mmu_pages(struct kvm_vcpu *vcpu)
2640 {
2641         struct kvm_mmu_page *sp;
2642
2643         while (!list_empty(&vcpu->kvm->arch.active_mmu_pages)) {
2644                 sp = container_of(vcpu->kvm->arch.active_mmu_pages.next,
2645                                   struct kvm_mmu_page, link);
2646                 kvm_mmu_zap_page(vcpu->kvm, sp);
2647                 cond_resched();
2648         }
2649         free_page((unsigned long)vcpu->arch.mmu.pae_root);
2650 }
2651
2652 static int alloc_mmu_pages(struct kvm_vcpu *vcpu)
2653 {
2654         struct page *page;
2655         int i;
2656
2657         ASSERT(vcpu);
2658
2659         if (vcpu->kvm->arch.n_requested_mmu_pages)
2660                 vcpu->kvm->arch.n_free_mmu_pages =
2661                                         vcpu->kvm->arch.n_requested_mmu_pages;
2662         else
2663                 vcpu->kvm->arch.n_free_mmu_pages =
2664                                         vcpu->kvm->arch.n_alloc_mmu_pages;
2665         /*
2666          * When emulating 32-bit mode, cr3 is only 32 bits even on x86_64.
2667          * Therefore we need to allocate shadow page tables in the first
2668          * 4GB of memory, which happens to fit the DMA32 zone.
2669          */
2670         page = alloc_page(GFP_KERNEL | __GFP_DMA32);
2671         if (!page)
2672                 goto error_1;
2673         vcpu->arch.mmu.pae_root = page_address(page);
2674         for (i = 0; i < 4; ++i)
2675                 vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
2676
2677         return 0;
2678
2679 error_1:
2680         free_mmu_pages(vcpu);
2681         return -ENOMEM;
2682 }
2683
2684 int kvm_mmu_create(struct kvm_vcpu *vcpu)
2685 {
2686         ASSERT(vcpu);
2687         ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
2688
2689         return alloc_mmu_pages(vcpu);
2690 }
2691
2692 int kvm_mmu_setup(struct kvm_vcpu *vcpu)
2693 {
2694         ASSERT(vcpu);
2695         ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
2696
2697         return init_kvm_mmu(vcpu);
2698 }
2699
2700 void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
2701 {
2702         ASSERT(vcpu);
2703
2704         destroy_kvm_mmu(vcpu);
2705         free_mmu_pages(vcpu);
2706         mmu_free_memory_caches(vcpu);
2707 }
2708
2709 void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
2710 {
2711         struct kvm_mmu_page *sp;
2712
2713         spin_lock(&kvm->mmu_lock);
2714         list_for_each_entry(sp, &kvm->arch.active_mmu_pages, link) {
2715                 int i;
2716                 u64 *pt;
2717
2718                 if (!test_bit(slot, sp->slot_bitmap))
2719                         continue;
2720
2721                 pt = sp->spt;
2722                 for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
2723                         /* avoid RMW */
2724                         if (pt[i] & PT_WRITABLE_MASK)
2725                                 pt[i] &= ~PT_WRITABLE_MASK;
2726         }
2727         kvm_flush_remote_tlbs(kvm);
2728         spin_unlock(&kvm->mmu_lock);
2729 }
2730
2731 void kvm_mmu_zap_all(struct kvm *kvm)
2732 {
2733         struct kvm_mmu_page *sp, *node;
2734
2735         spin_lock(&kvm->mmu_lock);
2736         list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link)
2737                 if (kvm_mmu_zap_page(kvm, sp))
2738                         node = container_of(kvm->arch.active_mmu_pages.next,
2739                                             struct kvm_mmu_page, link);
2740         spin_unlock(&kvm->mmu_lock);
2741
2742         kvm_flush_remote_tlbs(kvm);
2743 }
2744
2745 static void kvm_mmu_remove_one_alloc_mmu_page(struct kvm *kvm)
2746 {
2747         struct kvm_mmu_page *page;
2748
2749         page = container_of(kvm->arch.active_mmu_pages.prev,
2750                             struct kvm_mmu_page, link);
2751         kvm_mmu_zap_page(kvm, page);
2752 }
2753
2754 static int mmu_shrink(int nr_to_scan, gfp_t gfp_mask)
2755 {
2756         struct kvm *kvm;
2757         struct kvm *kvm_freed = NULL;
2758         int cache_count = 0;
2759
2760         spin_lock(&kvm_lock);
2761
2762         list_for_each_entry(kvm, &vm_list, vm_list) {
2763                 int npages;
2764
2765                 if (!down_read_trylock(&kvm->slots_lock))
2766                         continue;
2767                 spin_lock(&kvm->mmu_lock);
2768                 npages = kvm->arch.n_alloc_mmu_pages -
2769                          kvm->arch.n_free_mmu_pages;
2770                 cache_count += npages;
2771                 if (!kvm_freed && nr_to_scan > 0 && npages > 0) {
2772                         kvm_mmu_remove_one_alloc_mmu_page(kvm);
2773                         cache_count--;
2774                         kvm_freed = kvm;
2775                 }
2776                 nr_to_scan--;
2777
2778                 spin_unlock(&kvm->mmu_lock);
2779                 up_read(&kvm->slots_lock);
2780         }
2781         if (kvm_freed)
2782                 list_move_tail(&kvm_freed->vm_list, &vm_list);
2783
2784         spin_unlock(&kvm_lock);
2785
2786         return cache_count;
2787 }
2788
2789 static struct shrinker mmu_shrinker = {
2790         .shrink = mmu_shrink,
2791         .seeks = DEFAULT_SEEKS * 10,
2792 };
2793
2794 static void mmu_destroy_caches(void)
2795 {
2796         if (pte_chain_cache)
2797                 kmem_cache_destroy(pte_chain_cache);
2798         if (rmap_desc_cache)
2799                 kmem_cache_destroy(rmap_desc_cache);
2800         if (mmu_page_header_cache)
2801                 kmem_cache_destroy(mmu_page_header_cache);
2802 }
2803
2804 void kvm_mmu_module_exit(void)
2805 {
2806         mmu_destroy_caches();
2807         unregister_shrinker(&mmu_shrinker);
2808 }
2809
2810 int kvm_mmu_module_init(void)
2811 {
2812         pte_chain_cache = kmem_cache_create("kvm_pte_chain",
2813                                             sizeof(struct kvm_pte_chain),
2814                                             0, 0, NULL);
2815         if (!pte_chain_cache)
2816                 goto nomem;
2817         rmap_desc_cache = kmem_cache_create("kvm_rmap_desc",
2818                                             sizeof(struct kvm_rmap_desc),
2819                                             0, 0, NULL);
2820         if (!rmap_desc_cache)
2821                 goto nomem;
2822
2823         mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
2824                                                   sizeof(struct kvm_mmu_page),
2825                                                   0, 0, NULL);
2826         if (!mmu_page_header_cache)
2827                 goto nomem;
2828
2829         register_shrinker(&mmu_shrinker);
2830
2831         return 0;
2832
2833 nomem:
2834         mmu_destroy_caches();
2835         return -ENOMEM;
2836 }
2837
2838 /*
2839  * Caculate mmu pages needed for kvm.
2840  */
2841 unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
2842 {
2843         int i;
2844         unsigned int nr_mmu_pages;
2845         unsigned int  nr_pages = 0;
2846
2847         for (i = 0; i < kvm->nmemslots; i++)
2848                 nr_pages += kvm->memslots[i].npages;
2849
2850         nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000;
2851         nr_mmu_pages = max(nr_mmu_pages,
2852                         (unsigned int) KVM_MIN_ALLOC_MMU_PAGES);
2853
2854         return nr_mmu_pages;
2855 }
2856
2857 static void *pv_mmu_peek_buffer(struct kvm_pv_mmu_op_buffer *buffer,
2858                                 unsigned len)
2859 {
2860         if (len > buffer->len)
2861                 return NULL;
2862         return buffer->ptr;
2863 }
2864
2865 static void *pv_mmu_read_buffer(struct kvm_pv_mmu_op_buffer *buffer,
2866                                 unsigned len)
2867 {
2868         void *ret;
2869
2870         ret = pv_mmu_peek_buffer(buffer, len);
2871         if (!ret)
2872                 return ret;
2873         buffer->ptr += len;
2874         buffer->len -= len;
2875         buffer->processed += len;
2876         return ret;
2877 }
2878
2879 static int kvm_pv_mmu_write(struct kvm_vcpu *vcpu,
2880                              gpa_t addr, gpa_t value)
2881 {
2882         int bytes = 8;
2883         int r;
2884
2885         if (!is_long_mode(vcpu) && !is_pae(vcpu))
2886                 bytes = 4;
2887
2888         r = mmu_topup_memory_caches(vcpu);
2889         if (r)
2890                 return r;
2891
2892         if (!emulator_write_phys(vcpu, addr, &value, bytes))
2893                 return -EFAULT;
2894
2895         return 1;
2896 }
2897
2898 static int kvm_pv_mmu_flush_tlb(struct kvm_vcpu *vcpu)
2899 {
2900         kvm_set_cr3(vcpu, vcpu->arch.cr3);
2901         return 1;
2902 }
2903
2904 static int kvm_pv_mmu_release_pt(struct kvm_vcpu *vcpu, gpa_t addr)
2905 {
2906         spin_lock(&vcpu->kvm->mmu_lock);
2907         mmu_unshadow(vcpu->kvm, addr >> PAGE_SHIFT);
2908         spin_unlock(&vcpu->kvm->mmu_lock);
2909         return 1;
2910 }
2911
2912 static int kvm_pv_mmu_op_one(struct kvm_vcpu *vcpu,
2913                              struct kvm_pv_mmu_op_buffer *buffer)
2914 {
2915         struct kvm_mmu_op_header *header;
2916
2917         header = pv_mmu_peek_buffer(buffer, sizeof *header);
2918         if (!header)
2919                 return 0;
2920         switch (header->op) {
2921         case KVM_MMU_OP_WRITE_PTE: {
2922                 struct kvm_mmu_op_write_pte *wpte;
2923
2924                 wpte = pv_mmu_read_buffer(buffer, sizeof *wpte);
2925                 if (!wpte)
2926                         return 0;
2927                 return kvm_pv_mmu_write(vcpu, wpte->pte_phys,
2928                                         wpte->pte_val);
2929         }
2930         case KVM_MMU_OP_FLUSH_TLB: {
2931                 struct kvm_mmu_op_flush_tlb *ftlb;
2932
2933                 ftlb = pv_mmu_read_buffer(buffer, sizeof *ftlb);
2934                 if (!ftlb)
2935                         return 0;
2936                 return kvm_pv_mmu_flush_tlb(vcpu);
2937         }
2938         case KVM_MMU_OP_RELEASE_PT: {
2939                 struct kvm_mmu_op_release_pt *rpt;
2940
2941                 rpt = pv_mmu_read_buffer(buffer, sizeof *rpt);
2942                 if (!rpt)
2943                         return 0;
2944                 return kvm_pv_mmu_release_pt(vcpu, rpt->pt_phys);
2945         }
2946         default: return 0;
2947         }
2948 }
2949
2950 int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes,
2951                   gpa_t addr, unsigned long *ret)
2952 {
2953         int r;
2954         struct kvm_pv_mmu_op_buffer *buffer = &vcpu->arch.mmu_op_buffer;
2955
2956         buffer->ptr = buffer->buf;
2957         buffer->len = min_t(unsigned long, bytes, sizeof buffer->buf);
2958         buffer->processed = 0;
2959
2960         r = kvm_read_guest(vcpu->kvm, addr, buffer->buf, buffer->len);
2961         if (r)
2962                 goto out;
2963
2964         while (buffer->len) {
2965                 r = kvm_pv_mmu_op_one(vcpu, buffer);
2966                 if (r < 0)
2967                         goto out;
2968                 if (r == 0)
2969                         break;
2970         }
2971
2972         r = 1;
2973 out:
2974         *ret = buffer->processed;
2975         return r;
2976 }
2977
2978 #ifdef AUDIT
2979
2980 static const char *audit_msg;
2981
2982 static gva_t canonicalize(gva_t gva)
2983 {
2984 #ifdef CONFIG_X86_64
2985         gva = (long long)(gva << 16) >> 16;
2986 #endif
2987         return gva;
2988 }
2989
2990 static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
2991                                 gva_t va, int level)
2992 {
2993         u64 *pt = __va(page_pte & PT64_BASE_ADDR_MASK);
2994         int i;
2995         gva_t va_delta = 1ul << (PAGE_SHIFT + 9 * (level - 1));
2996
2997         for (i = 0; i < PT64_ENT_PER_PAGE; ++i, va += va_delta) {
2998                 u64 ent = pt[i];
2999
3000                 if (ent == shadow_trap_nonpresent_pte)
3001                         continue;
3002
3003                 va = canonicalize(va);
3004                 if (level > 1) {
3005                         if (ent == shadow_notrap_nonpresent_pte)
3006                                 printk(KERN_ERR "audit: (%s) nontrapping pte"
3007                                        " in nonleaf level: levels %d gva %lx"
3008                                        " level %d pte %llx\n", audit_msg,
3009                                        vcpu->arch.mmu.root_level, va, level, ent);
3010
3011                         audit_mappings_page(vcpu, ent, va, level - 1);
3012                 } else {
3013                         gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, va);
3014                         hpa_t hpa = (hpa_t)gpa_to_pfn(vcpu, gpa) << PAGE_SHIFT;
3015
3016                         if (is_shadow_present_pte(ent)
3017                             && (ent & PT64_BASE_ADDR_MASK) != hpa)
3018                                 printk(KERN_ERR "xx audit error: (%s) levels %d"
3019                                        " gva %lx gpa %llx hpa %llx ent %llx %d\n",
3020                                        audit_msg, vcpu->arch.mmu.root_level,
3021                                        va, gpa, hpa, ent,
3022                                        is_shadow_present_pte(ent));
3023                         else if (ent == shadow_notrap_nonpresent_pte
3024                                  && !is_error_hpa(hpa))
3025                                 printk(KERN_ERR "audit: (%s) notrap shadow,"
3026                                        " valid guest gva %lx\n", audit_msg, va);
3027                         kvm_release_pfn_clean(pfn);
3028
3029                 }
3030         }
3031 }
3032
3033 static void audit_mappings(struct kvm_vcpu *vcpu)
3034 {
3035         unsigned i;
3036
3037         if (vcpu->arch.mmu.root_level == 4)
3038                 audit_mappings_page(vcpu, vcpu->arch.mmu.root_hpa, 0, 4);
3039         else
3040                 for (i = 0; i < 4; ++i)
3041                         if (vcpu->arch.mmu.pae_root[i] & PT_PRESENT_MASK)
3042                                 audit_mappings_page(vcpu,
3043                                                     vcpu->arch.mmu.pae_root[i],
3044                                                     i << 30,
3045                                                     2);
3046 }
3047
3048 static int count_rmaps(struct kvm_vcpu *vcpu)
3049 {
3050         int nmaps = 0;
3051         int i, j, k;
3052
3053         for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
3054                 struct kvm_memory_slot *m = &vcpu->kvm->memslots[i];
3055                 struct kvm_rmap_desc *d;
3056
3057                 for (j = 0; j < m->npages; ++j) {
3058                         unsigned long *rmapp = &m->rmap[j];
3059
3060                         if (!*rmapp)
3061                                 continue;
3062                         if (!(*rmapp & 1)) {
3063                                 ++nmaps;
3064                                 continue;
3065                         }
3066                         d = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
3067                         while (d) {
3068                                 for (k = 0; k < RMAP_EXT; ++k)
3069                                         if (d->shadow_ptes[k])
3070                                                 ++nmaps;
3071                                         else
3072                                                 break;
3073                                 d = d->more;
3074                         }
3075                 }
3076         }
3077         return nmaps;
3078 }
3079
3080 static int count_writable_mappings(struct kvm_vcpu *vcpu)
3081 {
3082         int nmaps = 0;
3083         struct kvm_mmu_page *sp;
3084         int i;
3085
3086         list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
3087                 u64 *pt = sp->spt;
3088
3089                 if (sp->role.level != PT_PAGE_TABLE_LEVEL)
3090                         continue;
3091
3092                 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
3093                         u64 ent = pt[i];
3094
3095                         if (!(ent & PT_PRESENT_MASK))
3096                                 continue;
3097                         if (!(ent & PT_WRITABLE_MASK))
3098                                 continue;
3099                         ++nmaps;
3100                 }
3101         }
3102         return nmaps;
3103 }
3104
3105 static void audit_rmap(struct kvm_vcpu *vcpu)
3106 {
3107         int n_rmap = count_rmaps(vcpu);
3108         int n_actual = count_writable_mappings(vcpu);
3109
3110         if (n_rmap != n_actual)
3111                 printk(KERN_ERR "%s: (%s) rmap %d actual %d\n",
3112                        __func__, audit_msg, n_rmap, n_actual);
3113 }
3114
3115 static void audit_write_protection(struct kvm_vcpu *vcpu)
3116 {
3117         struct kvm_mmu_page *sp;
3118         struct kvm_memory_slot *slot;
3119         unsigned long *rmapp;
3120         gfn_t gfn;
3121
3122         list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
3123                 if (sp->role.direct)
3124                         continue;
3125
3126                 gfn = unalias_gfn(vcpu->kvm, sp->gfn);
3127                 slot = gfn_to_memslot_unaliased(vcpu->kvm, sp->gfn);
3128                 rmapp = &slot->rmap[gfn - slot->base_gfn];
3129                 if (*rmapp)
3130                         printk(KERN_ERR "%s: (%s) shadow page has writable"
3131                                " mappings: gfn %lx role %x\n",
3132                                __func__, audit_msg, sp->gfn,
3133                                sp->role.word);
3134         }
3135 }
3136
3137 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg)
3138 {
3139         int olddbg = dbg;
3140
3141         dbg = 0;
3142         audit_msg = msg;
3143         audit_rmap(vcpu);
3144         audit_write_protection(vcpu);
3145         audit_mappings(vcpu);
3146         dbg = olddbg;
3147 }
3148
3149 #endif