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 "vmx.h"
  21 #include "mmu.h"
  22
  23 #include <linux/kvm_host.h>
  24 #include <linux/types.h>
  25 #include <linux/string.h>
  26 #include <linux/mm.h>
  27 #include <linux/highmem.h>
  28 #include <linux/module.h>
  29 #include <linux/swap.h>
  30 #include <linux/hugetlb.h>
  31 #include <linux/compiler.h>
  32
  33 #include <asm/page.h>
  34 #include <asm/cmpxchg.h>
  35 #include <asm/io.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 #ifndef MMU_DEBUG
  74 #define ASSERT(x) do { } while (0)
  75 #else
  76 #define ASSERT(x)                                                       \
  77         if (!(x)) {                                                     \
  78                 printk(KERN_WARNING "assertion failed %s:%d: %s\n",     \
  79                        __FILE__, __LINE__, #x);                         \
  80         }
  81 #endif
  82
  83 #define PT_FIRST_AVAIL_BITS_SHIFT 9
  84 #define PT64_SECOND_AVAIL_BITS_SHIFT 52
  85
  86 #define VALID_PAGE(x) ((x) != INVALID_PAGE)
  87
  88 #define PT64_LEVEL_BITS 9
  89
  90 #define PT64_LEVEL_SHIFT(level) \
  91                 (PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS)
  92
  93 #define PT64_LEVEL_MASK(level) \
  94                 (((1ULL << PT64_LEVEL_BITS) - 1) << PT64_LEVEL_SHIFT(level))
  95
  96 #define PT64_INDEX(address, level)\
  97         (((address) >> PT64_LEVEL_SHIFT(level)) & ((1 << PT64_LEVEL_BITS) - 1))
  98
  99
 100 #define PT32_LEVEL_BITS 10
 101
 102 #define PT32_LEVEL_SHIFT(level) \
 103                 (PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS)
 104
 105 #define PT32_LEVEL_MASK(level) \
 106                 (((1ULL << PT32_LEVEL_BITS) - 1) << PT32_LEVEL_SHIFT(level))
 107
 108 #define PT32_INDEX(address, level)\
 109         (((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))
 110
 111
 112 #define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))
 113 #define PT64_DIR_BASE_ADDR_MASK \
 114         (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))
 115
 116 #define PT32_BASE_ADDR_MASK PAGE_MASK
 117 #define PT32_DIR_BASE_ADDR_MASK \
 118         (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
 119
 120 #define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK \
 121                         | PT64_NX_MASK)
 122
 123 #define PFERR_PRESENT_MASK (1U << 0)
 124 #define PFERR_WRITE_MASK (1U << 1)
 125 #define PFERR_USER_MASK (1U << 2)
 126 #define PFERR_FETCH_MASK (1U << 4)
 127
 128 #define PT_DIRECTORY_LEVEL 2
 129 #define PT_PAGE_TABLE_LEVEL 1
 130
 131 #define RMAP_EXT 4
 132
 133 #define ACC_EXEC_MASK    1
 134 #define ACC_WRITE_MASK   PT_WRITABLE_MASK
 135 #define ACC_USER_MASK    PT_USER_MASK
 136 #define ACC_ALL          (ACC_EXEC_MASK | ACC_WRITE_MASK | ACC_USER_MASK)
 137
 138 #define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)
 139
 140 struct kvm_rmap_desc {
 141         u64 *shadow_ptes[RMAP_EXT];
 142         struct kvm_rmap_desc *more;
 143 };
 144
 145 struct kvm_shadow_walk {
 146         int (*entry)(struct kvm_shadow_walk *walk, struct kvm_vcpu *vcpu,
 147                      u64 addr, u64 *spte, int level);
 148 };
 149
 150 static struct kmem_cache *pte_chain_cache;
 151 static struct kmem_cache *rmap_desc_cache;
 152 static struct kmem_cache *mmu_page_header_cache;
 153
 154 static u64 __read_mostly shadow_trap_nonpresent_pte;
 155 static u64 __read_mostly shadow_notrap_nonpresent_pte;
 156 static u64 __read_mostly shadow_base_present_pte;
 157 static u64 __read_mostly shadow_nx_mask;
 158 static u64 __read_mostly shadow_x_mask; /* mutual exclusive with nx_mask */
 159 static u64 __read_mostly shadow_user_mask;
 160 static u64 __read_mostly shadow_accessed_mask;
 161 static u64 __read_mostly shadow_dirty_mask;
 162
 163 void kvm_mmu_set_nonpresent_ptes(u64 trap_pte, u64 notrap_pte)
 164 {
 165         shadow_trap_nonpresent_pte = trap_pte;
 166         shadow_notrap_nonpresent_pte = notrap_pte;
 167 }
 168 EXPORT_SYMBOL_GPL(kvm_mmu_set_nonpresent_ptes);
 169
 170 void kvm_mmu_set_base_ptes(u64 base_pte)
 171 {
 172         shadow_base_present_pte = base_pte;
 173 }
 174 EXPORT_SYMBOL_GPL(kvm_mmu_set_base_ptes);
 175
 176 void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
 177                 u64 dirty_mask, u64 nx_mask, u64 x_mask)
 178 {
 179         shadow_user_mask = user_mask;
 180         shadow_accessed_mask = accessed_mask;
 181         shadow_dirty_mask = dirty_mask;
 182         shadow_nx_mask = nx_mask;
 183         shadow_x_mask = x_mask;
 184 }
 185 EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);
 186
 187 static int is_write_protection(struct kvm_vcpu *vcpu)
 188 {
 189         return vcpu->arch.cr0 & X86_CR0_WP;
 190 }
 191
 192 static int is_cpuid_PSE36(void)
 193 {
 194         return 1;
 195 }
 196
 197 static int is_nx(struct kvm_vcpu *vcpu)
 198 {
 199         return vcpu->arch.shadow_efer & EFER_NX;
 200 }
 201
 202 static int is_present_pte(unsigned long pte)
 203 {
 204         return pte & PT_PRESENT_MASK;
 205 }
 206
 207 static int is_shadow_present_pte(u64 pte)
 208 {
 209         return pte != shadow_trap_nonpresent_pte
 210                 && pte != shadow_notrap_nonpresent_pte;
 211 }
 212
 213 static int is_large_pte(u64 pte)
 214 {
 215         return pte & PT_PAGE_SIZE_MASK;
 216 }
 217
 218 static int is_writeble_pte(unsigned long pte)
 219 {
 220         return pte & PT_WRITABLE_MASK;
 221 }
 222
 223 static int is_dirty_pte(unsigned long pte)
 224 {
 225         return pte & shadow_dirty_mask;
 226 }
 227
 228 static int is_rmap_pte(u64 pte)
 229 {
 230         return is_shadow_present_pte(pte);
 231 }
 232
 233 static pfn_t spte_to_pfn(u64 pte)
 234 {
 235         return (pte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
 236 }
 237
 238 static gfn_t pse36_gfn_delta(u32 gpte)
 239 {
 240         int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT;
 241
 242         return (gpte & PT32_DIR_PSE36_MASK) << shift;
 243 }
 244
 245 static void set_shadow_pte(u64 *sptep, u64 spte)
 246 {
 247 #ifdef CONFIG_X86_64
 248         set_64bit((unsigned long *)sptep, spte);
 249 #else
 250         set_64bit((unsigned long long *)sptep, spte);
 251 #endif
 252 }
 253
 254 static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
 255                                   struct kmem_cache *base_cache, int min)
 256 {
 257         void *obj;
 258
 259         if (cache->nobjs >= min)
 260                 return 0;
 261         while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
 262                 obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
 263                 if (!obj)
 264                         return -ENOMEM;
 265                 cache->objects[cache->nobjs++] = obj;
 266         }
 267         return 0;
 268 }
 269
 270 static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
 271 {
 272         while (mc->nobjs)
 273                 kfree(mc->objects[--mc->nobjs]);
 274 }
 275
 276 static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
 277                                        int min)
 278 {
 279         struct page *page;
 280
 281         if (cache->nobjs >= min)
 282                 return 0;
 283         while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
 284                 page = alloc_page(GFP_KERNEL);
 285                 if (!page)
 286                         return -ENOMEM;
 287                 set_page_private(page, 0);
 288                 cache->objects[cache->nobjs++] = page_address(page);
 289         }
 290         return 0;
 291 }
 292
 293 static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
 294 {
 295         while (mc->nobjs)
 296                 free_page((unsigned long)mc->objects[--mc->nobjs]);
 297 }
 298
 299 static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
 300 {
 301         int r;
 302
 303         r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_chain_cache,
 304                                    pte_chain_cache, 4);
 305         if (r)
 306                 goto out;
 307         r = mmu_topup_memory_cache(&vcpu->arch.mmu_rmap_desc_cache,
 308                                    rmap_desc_cache, 1);
 309         if (r)
 310                 goto out;
 311         r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
 312         if (r)
 313                 goto out;
 314         r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
 315                                    mmu_page_header_cache, 4);
 316 out:
 317         return r;
 318 }
 319
 320 static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
 321 {
 322         mmu_free_memory_cache(&vcpu->arch.mmu_pte_chain_cache);
 323         mmu_free_memory_cache(&vcpu->arch.mmu_rmap_desc_cache);
 324         mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache);
 325         mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache);
 326 }
 327
 328 static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc,
 329                                     size_t size)
 330 {
 331         void *p;
 332
 333         BUG_ON(!mc->nobjs);
 334         p = mc->objects[--mc->nobjs];
 335         memset(p, 0, size);
 336         return p;
 337 }
 338
 339 static struct kvm_pte_chain *mmu_alloc_pte_chain(struct kvm_vcpu *vcpu)
 340 {
 341         return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_chain_cache,
 342                                       sizeof(struct kvm_pte_chain));
 343 }
 344
 345 static void mmu_free_pte_chain(struct kvm_pte_chain *pc)
 346 {
 347         kfree(pc);
 348 }
 349
 350 static struct kvm_rmap_desc *mmu_alloc_rmap_desc(struct kvm_vcpu *vcpu)
 351 {
 352         return mmu_memory_cache_alloc(&vcpu->arch.mmu_rmap_desc_cache,
 353                                       sizeof(struct kvm_rmap_desc));
 354 }
 355
 356 static void mmu_free_rmap_desc(struct kvm_rmap_desc *rd)
 357 {
 358         kfree(rd);
 359 }
 360
 361 /*
 362  * Return the pointer to the largepage write count for a given
 363  * gfn, handling slots that are not large page aligned.
 364  */
 365 static int *slot_largepage_idx(gfn_t gfn, struct kvm_memory_slot *slot)
 366 {
 367         unsigned long idx;
 368
 369         idx = (gfn / KVM_PAGES_PER_HPAGE) -
 370               (slot->base_gfn / KVM_PAGES_PER_HPAGE);
 371         return &slot->lpage_info[idx].write_count;
 372 }
 373
 374 static void account_shadowed(struct kvm *kvm, gfn_t gfn)
 375 {
 376         int *write_count;
 377
 378         write_count = slot_largepage_idx(gfn, gfn_to_memslot(kvm, gfn));
 379         *write_count += 1;
 380 }
 381
 382 static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn)
 383 {
 384         int *write_count;
 385
 386         write_count = slot_largepage_idx(gfn, gfn_to_memslot(kvm, gfn));
 387         *write_count -= 1;
 388         WARN_ON(*write_count < 0);
 389 }
 390
 391 static int has_wrprotected_page(struct kvm *kvm, gfn_t gfn)
 392 {
 393         struct kvm_memory_slot *slot = gfn_to_memslot(kvm, gfn);
 394         int *largepage_idx;
 395
 396         if (slot) {
 397                 largepage_idx = slot_largepage_idx(gfn, slot);
 398                 return *largepage_idx;
 399         }
 400
 401         return 1;
 402 }
 403
 404 static int host_largepage_backed(struct kvm *kvm, gfn_t gfn)
 405 {
 406         struct vm_area_struct *vma;
 407         unsigned long addr;
 408         int ret = 0;
 409
 410         addr = gfn_to_hva(kvm, gfn);
 411         if (kvm_is_error_hva(addr))
 412                 return ret;
 413
 414         down_read(&current->mm->mmap_sem);
 415         vma = find_vma(current->mm, addr);
 416         if (vma && is_vm_hugetlb_page(vma))
 417                 ret = 1;
 418         up_read(&current->mm->mmap_sem);
 419
 420         return ret;
 421 }
 422
 423 static int is_largepage_backed(struct kvm_vcpu *vcpu, gfn_t large_gfn)
 424 {
 425         struct kvm_memory_slot *slot;
 426
 427         if (has_wrprotected_page(vcpu->kvm, large_gfn))
 428                 return 0;
 429
 430         if (!host_largepage_backed(vcpu->kvm, large_gfn))
 431                 return 0;
 432
 433         slot = gfn_to_memslot(vcpu->kvm, large_gfn);
 434         if (slot && slot->dirty_bitmap)
 435                 return 0;
 436
 437         return 1;
 438 }
 439
 440 /*
 441  * Take gfn and return the reverse mapping to it.
 442  * Note: gfn must be unaliased before this function get called
 443  */
 444
 445 static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int lpage)
 446 {
 447         struct kvm_memory_slot *slot;
 448         unsigned long idx;
 449
 450         slot = gfn_to_memslot(kvm, gfn);
 451         if (!lpage)
 452                 return &slot->rmap[gfn - slot->base_gfn];
 453
 454         idx = (gfn / KVM_PAGES_PER_HPAGE) -
 455               (slot->base_gfn / KVM_PAGES_PER_HPAGE);
 456
 457         return &slot->lpage_info[idx].rmap_pde;
 458 }
 459
 460 /*
 461  * Reverse mapping data structures:
 462  *
 463  * If rmapp bit zero is zero, then rmapp point to the shadw page table entry
 464  * that points to page_address(page).
 465  *
 466  * If rmapp bit zero is one, (then rmap & ~1) points to a struct kvm_rmap_desc
 467  * containing more mappings.
 468  */
 469 static void rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn, int lpage)
 470 {
 471         struct kvm_mmu_page *sp;
 472         struct kvm_rmap_desc *desc;
 473         unsigned long *rmapp;
 474         int i;
 475
 476         if (!is_rmap_pte(*spte))
 477                 return;
 478         gfn = unalias_gfn(vcpu->kvm, gfn);
 479         sp = page_header(__pa(spte));
 480         sp->gfns[spte - sp->spt] = gfn;
 481         rmapp = gfn_to_rmap(vcpu->kvm, gfn, lpage);
 482         if (!*rmapp) {
 483                 rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte);
 484                 *rmapp = (unsigned long)spte;
 485         } else if (!(*rmapp & 1)) {
 486                 rmap_printk("rmap_add: %p %llx 1->many\n", spte, *spte);
 487                 desc = mmu_alloc_rmap_desc(vcpu);
 488                 desc->shadow_ptes[0] = (u64 *)*rmapp;
 489                 desc->shadow_ptes[1] = spte;
 490                 *rmapp = (unsigned long)desc | 1;
 491         } else {
 492                 rmap_printk("rmap_add: %p %llx many->many\n", spte, *spte);
 493                 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
 494                 while (desc->shadow_ptes[RMAP_EXT-1] && desc->more)
 495                         desc = desc->more;
 496                 if (desc->shadow_ptes[RMAP_EXT-1]) {
 497                         desc->more = mmu_alloc_rmap_desc(vcpu);
 498                         desc = desc->more;
 499                 }
 500                 for (i = 0; desc->shadow_ptes[i]; ++i)
 501                         ;
 502                 desc->shadow_ptes[i] = spte;
 503         }
 504 }
 505
 506 static void rmap_desc_remove_entry(unsigned long *rmapp,
 507                                    struct kvm_rmap_desc *desc,
 508                                    int i,
 509                                    struct kvm_rmap_desc *prev_desc)
 510 {
 511         int j;
 512
 513         for (j = RMAP_EXT - 1; !desc->shadow_ptes[j] && j > i; --j)
 514                 ;
 515         desc->shadow_ptes[i] = desc->shadow_ptes[j];
 516         desc->shadow_ptes[j] = NULL;
 517         if (j != 0)
 518                 return;
 519         if (!prev_desc && !desc->more)
 520                 *rmapp = (unsigned long)desc->shadow_ptes[0];
 521         else
 522                 if (prev_desc)
 523                         prev_desc->more = desc->more;
 524                 else
 525                         *rmapp = (unsigned long)desc->more | 1;
 526         mmu_free_rmap_desc(desc);
 527 }
 528
 529 static void rmap_remove(struct kvm *kvm, u64 *spte)
 530 {
 531         struct kvm_rmap_desc *desc;
 532         struct kvm_rmap_desc *prev_desc;
 533         struct kvm_mmu_page *sp;
 534         pfn_t pfn;
 535         unsigned long *rmapp;
 536         int i;
 537
 538         if (!is_rmap_pte(*spte))
 539                 return;
 540         sp = page_header(__pa(spte));
 541         pfn = spte_to_pfn(*spte);
 542         if (*spte & shadow_accessed_mask)
 543                 kvm_set_pfn_accessed(pfn);
 544         if (is_writeble_pte(*spte))
 545                 kvm_release_pfn_dirty(pfn);
 546         else
 547                 kvm_release_pfn_clean(pfn);
 548         rmapp = gfn_to_rmap(kvm, sp->gfns[spte - sp->spt], is_large_pte(*spte));
 549         if (!*rmapp) {
 550                 printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte);
 551                 BUG();
 552         } else if (!(*rmapp & 1)) {
 553                 rmap_printk("rmap_remove:  %p %llx 1->0\n", spte, *spte);
 554                 if ((u64 *)*rmapp != spte) {
 555                         printk(KERN_ERR "rmap_remove:  %p %llx 1->BUG\n",
 556                                spte, *spte);
 557                         BUG();
 558                 }
 559                 *rmapp = 0;
 560         } else {
 561                 rmap_printk("rmap_remove:  %p %llx many->many\n", spte, *spte);
 562                 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
 563                 prev_desc = NULL;
 564                 while (desc) {
 565                         for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i)
 566                                 if (desc->shadow_ptes[i] == spte) {
 567                                         rmap_desc_remove_entry(rmapp,
 568                                                                desc, i,
 569                                                                prev_desc);
 570                                         return;
 571                                 }
 572                         prev_desc = desc;
 573                         desc = desc->more;
 574                 }
 575                 BUG();
 576         }
 577 }
 578
 579 static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte)
 580 {
 581         struct kvm_rmap_desc *desc;
 582         struct kvm_rmap_desc *prev_desc;
 583         u64 *prev_spte;
 584         int i;
 585
 586         if (!*rmapp)
 587                 return NULL;
 588         else if (!(*rmapp & 1)) {
 589                 if (!spte)
 590                         return (u64 *)*rmapp;
 591                 return NULL;
 592         }
 593         desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
 594         prev_desc = NULL;
 595         prev_spte = NULL;
 596         while (desc) {
 597                 for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i) {
 598                         if (prev_spte == spte)
 599                                 return desc->shadow_ptes[i];
 600                         prev_spte = desc->shadow_ptes[i];
 601                 }
 602                 desc = desc->more;
 603         }
 604         return NULL;
 605 }
 606
 607 static void rmap_write_protect(struct kvm *kvm, u64 gfn)
 608 {
 609         unsigned long *rmapp;
 610         u64 *spte;
 611         int write_protected = 0;
 612
 613         gfn = unalias_gfn(kvm, gfn);
 614         rmapp = gfn_to_rmap(kvm, gfn, 0);
 615
 616         spte = rmap_next(kvm, rmapp, NULL);
 617         while (spte) {
 618                 BUG_ON(!spte);
 619                 BUG_ON(!(*spte & PT_PRESENT_MASK));
 620                 rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
 621                 if (is_writeble_pte(*spte)) {
 622                         set_shadow_pte(spte, *spte & ~PT_WRITABLE_MASK);
 623                         write_protected = 1;
 624                 }
 625                 spte = rmap_next(kvm, rmapp, spte);
 626         }
 627         if (write_protected) {
 628                 pfn_t pfn;
 629
 630                 spte = rmap_next(kvm, rmapp, NULL);
 631                 pfn = spte_to_pfn(*spte);
 632                 kvm_set_pfn_dirty(pfn);
 633         }
 634
 635         /* check for huge page mappings */
 636         rmapp = gfn_to_rmap(kvm, gfn, 1);
 637         spte = rmap_next(kvm, rmapp, NULL);
 638         while (spte) {
 639                 BUG_ON(!spte);
 640                 BUG_ON(!(*spte & PT_PRESENT_MASK));
 641                 BUG_ON((*spte & (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK)) != (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK));
 642                 pgprintk("rmap_write_protect(large): spte %p %llx %lld\n", spte, *spte, gfn);
 643                 if (is_writeble_pte(*spte)) {
 644                         rmap_remove(kvm, spte);
 645                         --kvm->stat.lpages;
 646                         set_shadow_pte(spte, shadow_trap_nonpresent_pte);
 647                         spte = NULL;
 648                         write_protected = 1;
 649                 }
 650                 spte = rmap_next(kvm, rmapp, spte);
 651         }
 652
 653         if (write_protected)
 654                 kvm_flush_remote_tlbs(kvm);
 655
 656         account_shadowed(kvm, gfn);
 657 }
 658
 659 static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp)
 660 {
 661         u64 *spte;
 662         int need_tlb_flush = 0;
 663
 664         while ((spte = rmap_next(kvm, rmapp, NULL))) {
 665                 BUG_ON(!(*spte & PT_PRESENT_MASK));
 666                 rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", spte, *spte);
 667                 rmap_remove(kvm, spte);
 668                 set_shadow_pte(spte, shadow_trap_nonpresent_pte);
 669                 need_tlb_flush = 1;
 670         }
 671         return need_tlb_flush;
 672 }
 673
 674 static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
 675                           int (*handler)(struct kvm *kvm, unsigned long *rmapp))
 676 {
 677         int i;
 678         int retval = 0;
 679
 680         /*
 681          * If mmap_sem isn't taken, we can look the memslots with only
 682          * the mmu_lock by skipping over the slots with userspace_addr == 0.
 683          */
 684         for (i = 0; i < kvm->nmemslots; i++) {
 685                 struct kvm_memory_slot *memslot = &kvm->memslots[i];
 686                 unsigned long start = memslot->userspace_addr;
 687                 unsigned long end;
 688
 689                 /* mmu_lock protects userspace_addr */
 690                 if (!start)
 691                         continue;
 692
 693                 end = start + (memslot->npages << PAGE_SHIFT);
 694                 if (hva >= start && hva < end) {
 695                         gfn_t gfn_offset = (hva - start) >> PAGE_SHIFT;
 696                         retval |= handler(kvm, &memslot->rmap[gfn_offset]);
 697                         retval |= handler(kvm,
 698                                           &memslot->lpage_info[
 699                                                   gfn_offset /
 700                                                   KVM_PAGES_PER_HPAGE].rmap_pde);
 701                 }
 702         }
 703
 704         return retval;
 705 }
 706
 707 int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
 708 {
 709         return kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
 710 }
 711
 712 static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp)
 713 {
 714         u64 *spte;
 715         int young = 0;
 716
 717         /* always return old for EPT */
 718         if (!shadow_accessed_mask)
 719                 return 0;
 720
 721         spte = rmap_next(kvm, rmapp, NULL);
 722         while (spte) {
 723                 int _young;
 724                 u64 _spte = *spte;
 725                 BUG_ON(!(_spte & PT_PRESENT_MASK));
 726                 _young = _spte & PT_ACCESSED_MASK;
 727                 if (_young) {
 728                         young = 1;
 729                         clear_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte);
 730                 }
 731                 spte = rmap_next(kvm, rmapp, spte);
 732         }
 733         return young;
 734 }
 735
 736 int kvm_age_hva(struct kvm *kvm, unsigned long hva)
 737 {
 738         return kvm_handle_hva(kvm, hva, kvm_age_rmapp);
 739 }
 740
 741 #ifdef MMU_DEBUG
 742 static int is_empty_shadow_page(u64 *spt)
 743 {
 744         u64 *pos;
 745         u64 *end;
 746
 747         for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
 748                 if (is_shadow_present_pte(*pos)) {
 749                         printk(KERN_ERR "%s: %p %llx\n", __func__,
 750                                pos, *pos);
 751                         return 0;
 752                 }
 753         return 1;
 754 }
 755 #endif
 756
 757 static void kvm_mmu_free_page(struct kvm *kvm, struct kvm_mmu_page *sp)
 758 {
 759         ASSERT(is_empty_shadow_page(sp->spt));
 760         list_del(&sp->link);
 761         __free_page(virt_to_page(sp->spt));
 762         __free_page(virt_to_page(sp->gfns));
 763         kfree(sp);
 764         ++kvm->arch.n_free_mmu_pages;
 765 }
 766
 767 static unsigned kvm_page_table_hashfn(gfn_t gfn)
 768 {
 769         return gfn & ((1 << KVM_MMU_HASH_SHIFT) - 1);
 770 }
 771
 772 static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
 773                                                u64 *parent_pte)
 774 {
 775         struct kvm_mmu_page *sp;
 776
 777         sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache, sizeof *sp);
 778         sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
 779         sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
 780         set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
 781         list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
 782         ASSERT(is_empty_shadow_page(sp->spt));
 783         sp->slot_bitmap = 0;
 784         sp->multimapped = 0;
 785         sp->parent_pte = parent_pte;
 786         --vcpu->kvm->arch.n_free_mmu_pages;
 787         return sp;
 788 }
 789
 790 static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
 791                                     struct kvm_mmu_page *sp, u64 *parent_pte)
 792 {
 793         struct kvm_pte_chain *pte_chain;
 794         struct hlist_node *node;
 795         int i;
 796
 797         if (!parent_pte)
 798                 return;
 799         if (!sp->multimapped) {
 800                 u64 *old = sp->parent_pte;
 801
 802                 if (!old) {
 803                         sp->parent_pte = parent_pte;
 804                         return;
 805                 }
 806                 sp->multimapped = 1;
 807                 pte_chain = mmu_alloc_pte_chain(vcpu);
 808                 INIT_HLIST_HEAD(&sp->parent_ptes);
 809                 hlist_add_head(&pte_chain->link, &sp->parent_ptes);
 810                 pte_chain->parent_ptes[0] = old;
 811         }
 812         hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link) {
 813                 if (pte_chain->parent_ptes[NR_PTE_CHAIN_ENTRIES-1])
 814                         continue;
 815                 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i)
 816                         if (!pte_chain->parent_ptes[i]) {
 817                                 pte_chain->parent_ptes[i] = parent_pte;
 818                                 return;
 819                         }
 820         }
 821         pte_chain = mmu_alloc_pte_chain(vcpu);
 822         BUG_ON(!pte_chain);
 823         hlist_add_head(&pte_chain->link, &sp->parent_ptes);
 824         pte_chain->parent_ptes[0] = parent_pte;
 825 }
 826
 827 static void mmu_page_remove_parent_pte(struct kvm_mmu_page *sp,
 828                                        u64 *parent_pte)
 829 {
 830         struct kvm_pte_chain *pte_chain;
 831         struct hlist_node *node;
 832         int i;
 833
 834         if (!sp->multimapped) {
 835                 BUG_ON(sp->parent_pte != parent_pte);
 836                 sp->parent_pte = NULL;
 837                 return;
 838         }
 839         hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
 840                 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
 841                         if (!pte_chain->parent_ptes[i])
 842                                 break;
 843                         if (pte_chain->parent_ptes[i] != parent_pte)
 844                                 continue;
 845                         while (i + 1 < NR_PTE_CHAIN_ENTRIES
 846                                 && pte_chain->parent_ptes[i + 1]) {
 847                                 pte_chain->parent_ptes[i]
 848                                         = pte_chain->parent_ptes[i + 1];
 849                                 ++i;
 850                         }
 851                         pte_chain->parent_ptes[i] = NULL;
 852                         if (i == 0) {
 853                                 hlist_del(&pte_chain->link);
 854                                 mmu_free_pte_chain(pte_chain);
 855                                 if (hlist_empty(&sp->parent_ptes)) {
 856                                         sp->multimapped = 0;
 857                                         sp->parent_pte = NULL;
 858                                 }
 859                         }
 860                         return;
 861                 }
 862         BUG();
 863 }
 864
 865 static void nonpaging_prefetch_page(struct kvm_vcpu *vcpu,
 866                                     struct kvm_mmu_page *sp)
 867 {
 868         int i;
 869
 870         for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
 871                 sp->spt[i] = shadow_trap_nonpresent_pte;
 872 }
 873
 874 static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm *kvm, gfn_t gfn)
 875 {
 876         unsigned index;
 877         struct hlist_head *bucket;
 878         struct kvm_mmu_page *sp;
 879         struct hlist_node *node;
 880
 881         pgprintk("%s: looking for gfn %lx\n", __func__, gfn);
 882         index = kvm_page_table_hashfn(gfn);
 883         bucket = &kvm->arch.mmu_page_hash[index];
 884         hlist_for_each_entry(sp, node, bucket, hash_link)
 885                 if (sp->gfn == gfn && !sp->role.metaphysical
 886                     && !sp->role.invalid) {
 887                         pgprintk("%s: found role %x\n",
 888                                  __func__, sp->role.word);
 889                         return sp;
 890                 }
 891         return NULL;
 892 }
 893
 894 static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
 895                                              gfn_t gfn,
 896                                              gva_t gaddr,
 897                                              unsigned level,
 898                                              int metaphysical,
 899                                              unsigned access,
 900                                              u64 *parent_pte)
 901 {
 902         union kvm_mmu_page_role role;
 903         unsigned index;
 904         unsigned quadrant;
 905         struct hlist_head *bucket;
 906         struct kvm_mmu_page *sp;
 907         struct hlist_node *node;
 908
 909         role.word = 0;
 910         role.glevels = vcpu->arch.mmu.root_level;
 911         role.level = level;
 912         role.metaphysical = metaphysical;
 913         role.access = access;
 914         if (vcpu->arch.mmu.root_level <= PT32_ROOT_LEVEL) {
 915                 quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
 916                 quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
 917                 role.quadrant = quadrant;
 918         }
 919         pgprintk("%s: looking gfn %lx role %x\n", __func__,
 920                  gfn, role.word);
 921         index = kvm_page_table_hashfn(gfn);
 922         bucket = &vcpu->kvm->arch.mmu_page_hash[index];
 923         hlist_for_each_entry(sp, node, bucket, hash_link)
 924                 if (sp->gfn == gfn && sp->role.word == role.word) {
 925                         mmu_page_add_parent_pte(vcpu, sp, parent_pte);
 926                         pgprintk("%s: found\n", __func__);
 927                         return sp;
 928                 }
 929         ++vcpu->kvm->stat.mmu_cache_miss;
 930         sp = kvm_mmu_alloc_page(vcpu, parent_pte);
 931         if (!sp)
 932                 return sp;
 933         pgprintk("%s: adding gfn %lx role %x\n", __func__, gfn, role.word);
 934         sp->gfn = gfn;
 935         sp->role = role;
 936         hlist_add_head(&sp->hash_link, bucket);
 937         if (!metaphysical)
 938                 rmap_write_protect(vcpu->kvm, gfn);
 939         if (shadow_trap_nonpresent_pte != shadow_notrap_nonpresent_pte)
 940                 vcpu->arch.mmu.prefetch_page(vcpu, sp);
 941         else
 942                 nonpaging_prefetch_page(vcpu, sp);
 943         return sp;
 944 }
 945
 946 static int walk_shadow(struct kvm_shadow_walk *walker,
 947                        struct kvm_vcpu *vcpu, u64 addr)
 948 {
 949         hpa_t shadow_addr;
 950         int level;
 951         int r;
 952         u64 *sptep;
 953         unsigned index;
 954
 955         shadow_addr = vcpu->arch.mmu.root_hpa;
 956         level = vcpu->arch.mmu.shadow_root_level;
 957         if (level == PT32E_ROOT_LEVEL) {
 958                 shadow_addr = vcpu->arch.mmu.pae_root[(addr >> 30) & 3];
 959                 shadow_addr &= PT64_BASE_ADDR_MASK;
 960                 --level;
 961         }
 962
 963         while (level >= PT_PAGE_TABLE_LEVEL) {
 964                 index = SHADOW_PT_INDEX(addr, level);
 965                 sptep = ((u64 *)__va(shadow_addr)) + index;
 966                 r = walker->entry(walker, vcpu, addr, sptep, level);
 967                 if (r)
 968                         return r;
 969                 shadow_addr = *sptep & PT64_BASE_ADDR_MASK;
 970                 --level;
 971         }
 972         return 0;
 973 }
 974
 975 static void kvm_mmu_page_unlink_children(struct kvm *kvm,
 976                                          struct kvm_mmu_page *sp)
 977 {
 978         unsigned i;
 979         u64 *pt;
 980         u64 ent;
 981
 982         pt = sp->spt;
 983
 984         if (sp->role.level == PT_PAGE_TABLE_LEVEL) {
 985                 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
 986                         if (is_shadow_present_pte(pt[i]))
 987                                 rmap_remove(kvm, &pt[i]);
 988                         pt[i] = shadow_trap_nonpresent_pte;
 989                 }
 990                 return;
 991         }
 992
 993         for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
 994                 ent = pt[i];
 995
 996                 if (is_shadow_present_pte(ent)) {
 997                         if (!is_large_pte(ent)) {
 998                                 ent &= PT64_BASE_ADDR_MASK;
 999                                 mmu_page_remove_parent_pte(page_header(ent),
1000                                                            &pt[i]);
1001                         } else {
1002                                 --kvm->stat.lpages;
1003                                 rmap_remove(kvm, &pt[i]);
1004                         }
1005                 }
1006                 pt[i] = shadow_trap_nonpresent_pte;
1007         }
1008 }
1009
1010 static void kvm_mmu_put_page(struct kvm_mmu_page *sp, u64 *parent_pte)
1011 {
1012         mmu_page_remove_parent_pte(sp, parent_pte);
1013 }
1014
1015 static void kvm_mmu_reset_last_pte_updated(struct kvm *kvm)
1016 {
1017         int i;
1018
1019         for (i = 0; i < KVM_MAX_VCPUS; ++i)
1020                 if (kvm->vcpus[i])
1021                         kvm->vcpus[i]->arch.last_pte_updated = NULL;
1022 }
1023
1024 static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp)
1025 {
1026         u64 *parent_pte;
1027
1028         while (sp->multimapped || sp->parent_pte) {
1029                 if (!sp->multimapped)
1030                         parent_pte = sp->parent_pte;
1031                 else {
1032                         struct kvm_pte_chain *chain;
1033
1034                         chain = container_of(sp->parent_ptes.first,
1035                                              struct kvm_pte_chain, link);
1036                         parent_pte = chain->parent_ptes[0];
1037                 }
1038                 BUG_ON(!parent_pte);
1039                 kvm_mmu_put_page(sp, parent_pte);
1040                 set_shadow_pte(parent_pte, shadow_trap_nonpresent_pte);
1041         }
1042 }
1043
1044 static void kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp)
1045 {
1046         ++kvm->stat.mmu_shadow_zapped;
1047         kvm_mmu_page_unlink_children(kvm, sp);
1048         kvm_mmu_unlink_parents(kvm, sp);
1049         kvm_flush_remote_tlbs(kvm);
1050         if (!sp->role.invalid && !sp->role.metaphysical)
1051                 unaccount_shadowed(kvm, sp->gfn);
1052         if (!sp->root_count) {
1053                 hlist_del(&sp->hash_link);
1054                 kvm_mmu_free_page(kvm, sp);
1055         } else {
1056                 sp->role.invalid = 1;
1057                 list_move(&sp->link, &kvm->arch.active_mmu_pages);
1058                 kvm_reload_remote_mmus(kvm);
1059         }
1060         kvm_mmu_reset_last_pte_updated(kvm);
1061 }
1062
1063 /*
1064  * Changing the number of mmu pages allocated to the vm
1065  * Note: if kvm_nr_mmu_pages is too small, you will get dead lock
1066  */
1067 void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages)
1068 {
1069         /*
1070          * If we set the number of mmu pages to be smaller be than the
1071          * number of actived pages , we must to free some mmu pages before we
1072          * change the value
1073          */
1074
1075         if ((kvm->arch.n_alloc_mmu_pages - kvm->arch.n_free_mmu_pages) >
1076             kvm_nr_mmu_pages) {
1077                 int n_used_mmu_pages = kvm->arch.n_alloc_mmu_pages
1078                                        - kvm->arch.n_free_mmu_pages;
1079
1080                 while (n_used_mmu_pages > kvm_nr_mmu_pages) {
1081                         struct kvm_mmu_page *page;
1082
1083                         page = container_of(kvm->arch.active_mmu_pages.prev,
1084                                             struct kvm_mmu_page, link);
1085                         kvm_mmu_zap_page(kvm, page);
1086                         n_used_mmu_pages--;
1087                 }
1088                 kvm->arch.n_free_mmu_pages = 0;
1089         }
1090         else
1091                 kvm->arch.n_free_mmu_pages += kvm_nr_mmu_pages
1092                                          - kvm->arch.n_alloc_mmu_pages;
1093
1094         kvm->arch.n_alloc_mmu_pages = kvm_nr_mmu_pages;
1095 }
1096
1097 static int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
1098 {
1099         unsigned index;
1100         struct hlist_head *bucket;
1101         struct kvm_mmu_page *sp;
1102         struct hlist_node *node, *n;
1103         int r;
1104
1105         pgprintk("%s: looking for gfn %lx\n", __func__, gfn);
1106         r = 0;
1107         index = kvm_page_table_hashfn(gfn);
1108         bucket = &kvm->arch.mmu_page_hash[index];
1109         hlist_for_each_entry_safe(sp, node, n, bucket, hash_link)
1110                 if (sp->gfn == gfn && !sp->role.metaphysical) {
1111                         pgprintk("%s: gfn %lx role %x\n", __func__, gfn,
1112                                  sp->role.word);
1113                         kvm_mmu_zap_page(kvm, sp);
1114                         r = 1;
1115                 }
1116         return r;
1117 }
1118
1119 static void mmu_unshadow(struct kvm *kvm, gfn_t gfn)
1120 {
1121         struct kvm_mmu_page *sp;
1122
1123         while ((sp = kvm_mmu_lookup_page(kvm, gfn)) != NULL) {
1124                 pgprintk("%s: zap %lx %x\n", __func__, gfn, sp->role.word);
1125                 kvm_mmu_zap_page(kvm, sp);
1126         }
1127 }
1128
1129 static void page_header_update_slot(struct kvm *kvm, void *pte, gfn_t gfn)
1130 {
1131         int slot = memslot_id(kvm, gfn_to_memslot(kvm, gfn));
1132         struct kvm_mmu_page *sp = page_header(__pa(pte));
1133
1134         __set_bit(slot, &sp->slot_bitmap);
1135 }
1136
1137 struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva)
1138 {
1139         struct page *page;
1140
1141         gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva);
1142
1143         if (gpa == UNMAPPED_GVA)
1144                 return NULL;
1145
1146         page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);
1147
1148         return page;
1149 }
1150
1151 static int set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
1152                     unsigned pte_access, int user_fault,
1153                     int write_fault, int dirty, int largepage,
1154                     gfn_t gfn, pfn_t pfn, bool speculative)
1155 {
1156         u64 spte;
1157         int ret = 0;
1158         /*
1159          * We don't set the accessed bit, since we sometimes want to see
1160          * whether the guest actually used the pte (in order to detect
1161          * demand paging).
1162          */
1163         spte = shadow_base_present_pte | shadow_dirty_mask;
1164         if (!speculative)
1165                 spte |= shadow_accessed_mask;
1166         if (!dirty)
1167                 pte_access &= ~ACC_WRITE_MASK;
1168         if (pte_access & ACC_EXEC_MASK)
1169                 spte |= shadow_x_mask;
1170         else
1171                 spte |= shadow_nx_mask;
1172         if (pte_access & ACC_USER_MASK)
1173                 spte |= shadow_user_mask;
1174         if (largepage)
1175                 spte |= PT_PAGE_SIZE_MASK;
1176
1177         spte |= (u64)pfn << PAGE_SHIFT;
1178
1179         if ((pte_access & ACC_WRITE_MASK)
1180             || (write_fault && !is_write_protection(vcpu) && !user_fault)) {
1181                 struct kvm_mmu_page *shadow;
1182
1183                 spte |= PT_WRITABLE_MASK;
1184
1185                 shadow = kvm_mmu_lookup_page(vcpu->kvm, gfn);
1186                 if (shadow ||
1187                    (largepage && has_wrprotected_page(vcpu->kvm, gfn))) {
1188                         pgprintk("%s: found shadow page for %lx, marking ro\n",
1189                                  __func__, gfn);
1190                         ret = 1;
1191                         pte_access &= ~ACC_WRITE_MASK;
1192                         if (is_writeble_pte(spte)) {
1193                                 spte &= ~PT_WRITABLE_MASK;
1194                                 kvm_x86_ops->tlb_flush(vcpu);
1195                         }
1196                 }
1197         }
1198
1199         if (pte_access & ACC_WRITE_MASK)
1200                 mark_page_dirty(vcpu->kvm, gfn);
1201
1202         set_shadow_pte(shadow_pte, spte);
1203         return ret;
1204 }
1205
1206
1207 static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
1208                          unsigned pt_access, unsigned pte_access,
1209                          int user_fault, int write_fault, int dirty,
1210                          int *ptwrite, int largepage, gfn_t gfn,
1211                          pfn_t pfn, bool speculative)
1212 {
1213         int was_rmapped = 0;
1214         int was_writeble = is_writeble_pte(*shadow_pte);
1215
1216         pgprintk("%s: spte %llx access %x write_fault %d"
1217                  " user_fault %d gfn %lx\n",
1218                  __func__, *shadow_pte, pt_access,
1219                  write_fault, user_fault, gfn);
1220
1221         if (is_rmap_pte(*shadow_pte)) {
1222                 /*
1223                  * If we overwrite a PTE page pointer with a 2MB PMD, unlink
1224                  * the parent of the now unreachable PTE.
1225                  */
1226                 if (largepage && !is_large_pte(*shadow_pte)) {
1227                         struct kvm_mmu_page *child;
1228                         u64 pte = *shadow_pte;
1229
1230                         child = page_header(pte & PT64_BASE_ADDR_MASK);
1231                         mmu_page_remove_parent_pte(child, shadow_pte);
1232                 } else if (pfn != spte_to_pfn(*shadow_pte)) {
1233                         pgprintk("hfn old %lx new %lx\n",
1234                                  spte_to_pfn(*shadow_pte), pfn);
1235                         rmap_remove(vcpu->kvm, shadow_pte);
1236                 } else {
1237                         if (largepage)
1238                                 was_rmapped = is_large_pte(*shadow_pte);
1239                         else
1240                                 was_rmapped = 1;
1241                 }
1242         }
1243         if (set_spte(vcpu, shadow_pte, pte_access, user_fault, write_fault,
1244                       dirty, largepage, gfn, pfn, speculative))
1245                 if (write_fault)
1246                         *ptwrite = 1;
1247
1248         pgprintk("%s: setting spte %llx\n", __func__, *shadow_pte);
1249         pgprintk("instantiating %s PTE (%s) at %ld (%llx) addr %p\n",
1250                  is_large_pte(*shadow_pte)? "2MB" : "4kB",
1251                  is_present_pte(*shadow_pte)?"RW":"R", gfn,
1252                  *shadow_pte, shadow_pte);
1253         if (!was_rmapped && is_large_pte(*shadow_pte))
1254                 ++vcpu->kvm->stat.lpages;
1255
1256         page_header_update_slot(vcpu->kvm, shadow_pte, gfn);
1257         if (!was_rmapped) {
1258                 rmap_add(vcpu, shadow_pte, gfn, largepage);
1259                 if (!is_rmap_pte(*shadow_pte))
1260                         kvm_release_pfn_clean(pfn);
1261         } else {
1262                 if (was_writeble)
1263                         kvm_release_pfn_dirty(pfn);
1264                 else
1265                         kvm_release_pfn_clean(pfn);
1266         }
1267         if (speculative) {
1268                 vcpu->arch.last_pte_updated = shadow_pte;
1269                 vcpu->arch.last_pte_gfn = gfn;
1270         }
1271 }
1272
1273 static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
1274 {
1275 }
1276
1277 struct direct_shadow_walk {
1278         struct kvm_shadow_walk walker;
1279         pfn_t pfn;
1280         int write;
1281         int largepage;
1282         int pt_write;
1283 };
1284
1285 static int direct_map_entry(struct kvm_shadow_walk *_walk,
1286                             struct kvm_vcpu *vcpu,
1287                             u64 addr, u64 *sptep, int level)
1288 {
1289         struct direct_shadow_walk *walk =
1290                 container_of(_walk, struct direct_shadow_walk, walker);
1291         struct kvm_mmu_page *sp;
1292         gfn_t pseudo_gfn;
1293         gfn_t gfn = addr >> PAGE_SHIFT;
1294
1295         if (level == PT_PAGE_TABLE_LEVEL
1296             || (walk->largepage && level == PT_DIRECTORY_LEVEL)) {
1297                 mmu_set_spte(vcpu, sptep, ACC_ALL, ACC_ALL,
1298                              0, walk->write, 1, &walk->pt_write,
1299                              walk->largepage, gfn, walk->pfn, false);
1300                 ++vcpu->stat.pf_fixed;
1301                 return 1;
1302         }
1303
1304         if (*sptep == shadow_trap_nonpresent_pte) {
1305                 pseudo_gfn = (addr & PT64_DIR_BASE_ADDR_MASK) >> PAGE_SHIFT;
1306                 sp = kvm_mmu_get_page(vcpu, pseudo_gfn, (gva_t)addr, level - 1,
1307                                       1, ACC_ALL, sptep);
1308                 if (!sp) {
1309                         pgprintk("nonpaging_map: ENOMEM\n");
1310                         kvm_release_pfn_clean(walk->pfn);
1311                         return -ENOMEM;
1312                 }
1313
1314                 set_shadow_pte(sptep,
1315                                __pa(sp->spt)
1316                                | PT_PRESENT_MASK | PT_WRITABLE_MASK
1317                                | shadow_user_mask | shadow_x_mask);
1318         }
1319         return 0;
1320 }
1321
1322 static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
1323                         int largepage, gfn_t gfn, pfn_t pfn)
1324 {
1325         int r;
1326         struct direct_shadow_walk walker = {
1327                 .walker = { .entry = direct_map_entry, },
1328                 .pfn = pfn,
1329                 .largepage = largepage,
1330                 .write = write,
1331                 .pt_write = 0,
1332         };
1333
1334         r = walk_shadow(&walker.walker, vcpu, gfn << PAGE_SHIFT);
1335         if (r < 0)
1336                 return r;
1337         return walker.pt_write;
1338 }
1339
1340 static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
1341 {
1342         int r;
1343         int largepage = 0;
1344         pfn_t pfn;
1345         unsigned long mmu_seq;
1346
1347         if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
1348                 gfn &= ~(KVM_PAGES_PER_HPAGE-1);
1349                 largepage = 1;
1350         }
1351
1352         mmu_seq = vcpu->kvm->mmu_notifier_seq;
1353         smp_rmb();
1354         pfn = gfn_to_pfn(vcpu->kvm, gfn);
1355
1356         /* mmio */
1357         if (is_error_pfn(pfn)) {
1358                 kvm_release_pfn_clean(pfn);
1359                 return 1;
1360         }
1361
1362         spin_lock(&vcpu->kvm->mmu_lock);
1363         if (mmu_notifier_retry(vcpu, mmu_seq))
1364                 goto out_unlock;
1365         kvm_mmu_free_some_pages(vcpu);
1366         r = __direct_map(vcpu, v, write, largepage, gfn, pfn);
1367         spin_unlock(&vcpu->kvm->mmu_lock);
1368
1369
1370         return r;
1371
1372 out_unlock:
1373         spin_unlock(&vcpu->kvm->mmu_lock);
1374         kvm_release_pfn_clean(pfn);
1375         return 0;
1376 }
1377
1378
1379 static void mmu_free_roots(struct kvm_vcpu *vcpu)
1380 {
1381         int i;
1382         struct kvm_mmu_page *sp;
1383
1384         if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
1385                 return;
1386         spin_lock(&vcpu->kvm->mmu_lock);
1387         if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
1388                 hpa_t root = vcpu->arch.mmu.root_hpa;
1389
1390                 sp = page_header(root);
1391                 --sp->root_count;
1392                 if (!sp->root_count && sp->role.invalid)
1393                         kvm_mmu_zap_page(vcpu->kvm, sp);
1394                 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
1395                 spin_unlock(&vcpu->kvm->mmu_lock);
1396                 return;
1397         }
1398         for (i = 0; i < 4; ++i) {
1399                 hpa_t root = vcpu->arch.mmu.pae_root[i];
1400
1401                 if (root) {
1402                         root &= PT64_BASE_ADDR_MASK;
1403                         sp = page_header(root);
1404                         --sp->root_count;
1405                         if (!sp->root_count && sp->role.invalid)
1406                                 kvm_mmu_zap_page(vcpu->kvm, sp);
1407                 }
1408                 vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
1409         }
1410         spin_unlock(&vcpu->kvm->mmu_lock);
1411         vcpu->arch.mmu.root_hpa = INVALID_PAGE;
1412 }
1413
1414 static void mmu_alloc_roots(struct kvm_vcpu *vcpu)
1415 {
1416         int i;
1417         gfn_t root_gfn;
1418         struct kvm_mmu_page *sp;
1419         int metaphysical = 0;
1420
1421         root_gfn = vcpu->arch.cr3 >> PAGE_SHIFT;
1422
1423         if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
1424                 hpa_t root = vcpu->arch.mmu.root_hpa;
1425
1426                 ASSERT(!VALID_PAGE(root));
1427                 if (tdp_enabled)
1428                         metaphysical = 1;
1429                 sp = kvm_mmu_get_page(vcpu, root_gfn, 0,
1430                                       PT64_ROOT_LEVEL, metaphysical,
1431                                       ACC_ALL, NULL);
1432                 root = __pa(sp->spt);
1433                 ++sp->root_count;
1434                 vcpu->arch.mmu.root_hpa = root;
1435                 return;
1436         }
1437         metaphysical = !is_paging(vcpu);
1438         if (tdp_enabled)
1439                 metaphysical = 1;
1440         for (i = 0; i < 4; ++i) {
1441                 hpa_t root = vcpu->arch.mmu.pae_root[i];
1442
1443                 ASSERT(!VALID_PAGE(root));
1444                 if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
1445                         if (!is_present_pte(vcpu->arch.pdptrs[i])) {
1446                                 vcpu->arch.mmu.pae_root[i] = 0;
1447                                 continue;
1448                         }
1449                         root_gfn = vcpu->arch.pdptrs[i] >> PAGE_SHIFT;
1450                 } else if (vcpu->arch.mmu.root_level == 0)
1451                         root_gfn = 0;
1452                 sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
1453                                       PT32_ROOT_LEVEL, metaphysical,
1454                                       ACC_ALL, NULL);
1455                 root = __pa(sp->spt);
1456                 ++sp->root_count;
1457                 vcpu->arch.mmu.pae_root[i] = root | PT_PRESENT_MASK;
1458         }
1459         vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
1460 }
1461
1462 static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr)
1463 {
1464         return vaddr;
1465 }
1466
1467 static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
1468                                 u32 error_code)
1469 {
1470         gfn_t gfn;
1471         int r;
1472
1473         pgprintk("%s: gva %lx error %x\n", __func__, gva, error_code);
1474         r = mmu_topup_memory_caches(vcpu);
1475         if (r)
1476                 return r;
1477
1478         ASSERT(vcpu);
1479         ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
1480
1481         gfn = gva >> PAGE_SHIFT;
1482
1483         return nonpaging_map(vcpu, gva & PAGE_MASK,
1484                              error_code & PFERR_WRITE_MASK, gfn);
1485 }
1486
1487 static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
1488                                 u32 error_code)
1489 {
1490         pfn_t pfn;
1491         int r;
1492         int largepage = 0;
1493         gfn_t gfn = gpa >> PAGE_SHIFT;
1494         unsigned long mmu_seq;
1495
1496         ASSERT(vcpu);
1497         ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
1498
1499         r = mmu_topup_memory_caches(vcpu);
1500         if (r)
1501                 return r;
1502
1503         if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
1504                 gfn &= ~(KVM_PAGES_PER_HPAGE-1);
1505                 largepage = 1;
1506         }
1507         mmu_seq = vcpu->kvm->mmu_notifier_seq;
1508         smp_rmb();
1509         pfn = gfn_to_pfn(vcpu->kvm, gfn);
1510         if (is_error_pfn(pfn)) {
1511                 kvm_release_pfn_clean(pfn);
1512                 return 1;
1513         }
1514         spin_lock(&vcpu->kvm->mmu_lock);
1515         if (mmu_notifier_retry(vcpu, mmu_seq))
1516                 goto out_unlock;
1517         kvm_mmu_free_some_pages(vcpu);
1518         r = __direct_map(vcpu, gpa, error_code & PFERR_WRITE_MASK,
1519                          largepage, gfn, pfn);
1520         spin_unlock(&vcpu->kvm->mmu_lock);
1521
1522         return r;
1523
1524 out_unlock:
1525         spin_unlock(&vcpu->kvm->mmu_lock);
1526         kvm_release_pfn_clean(pfn);
1527         return 0;
1528 }
1529
1530 static void nonpaging_free(struct kvm_vcpu *vcpu)
1531 {
1532         mmu_free_roots(vcpu);
1533 }
1534
1535 static int nonpaging_init_context(struct kvm_vcpu *vcpu)
1536 {
1537         struct kvm_mmu *context = &vcpu->arch.mmu;
1538
1539         context->new_cr3 = nonpaging_new_cr3;
1540         context->page_fault = nonpaging_page_fault;
1541         context->gva_to_gpa = nonpaging_gva_to_gpa;
1542         context->free = nonpaging_free;
1543         context->prefetch_page = nonpaging_prefetch_page;
1544         context->root_level = 0;
1545         context->shadow_root_level = PT32E_ROOT_LEVEL;
1546         context->root_hpa = INVALID_PAGE;
1547         return 0;
1548 }
1549
1550 void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
1551 {
1552         ++vcpu->stat.tlb_flush;
1553         kvm_x86_ops->tlb_flush(vcpu);
1554 }
1555
1556 static void paging_new_cr3(struct kvm_vcpu *vcpu)
1557 {
1558         pgprintk("%s: cr3 %lx\n", __func__, vcpu->arch.cr3);
1559         mmu_free_roots(vcpu);
1560 }
1561
1562 static void inject_page_fault(struct kvm_vcpu *vcpu,
1563                               u64 addr,
1564                               u32 err_code)
1565 {
1566         kvm_inject_page_fault(vcpu, addr, err_code);
1567 }
1568
1569 static void paging_free(struct kvm_vcpu *vcpu)
1570 {
1571         nonpaging_free(vcpu);
1572 }
1573
1574 #define PTTYPE 64
1575 #include "paging_tmpl.h"
1576 #undef PTTYPE
1577
1578 #define PTTYPE 32
1579 #include "paging_tmpl.h"
1580 #undef PTTYPE
1581
1582 static int paging64_init_context_common(struct kvm_vcpu *vcpu, int level)
1583 {
1584         struct kvm_mmu *context = &vcpu->arch.mmu;
1585
1586         ASSERT(is_pae(vcpu));
1587         context->new_cr3 = paging_new_cr3;
1588         context->page_fault = paging64_page_fault;
1589         context->gva_to_gpa = paging64_gva_to_gpa;
1590         context->prefetch_page = paging64_prefetch_page;
1591         context->free = paging_free;
1592         context->root_level = level;
1593         context->shadow_root_level = level;
1594         context->root_hpa = INVALID_PAGE;
1595         return 0;
1596 }
1597
1598 static int paging64_init_context(struct kvm_vcpu *vcpu)
1599 {
1600         return paging64_init_context_common(vcpu, PT64_ROOT_LEVEL);
1601 }
1602
1603 static int paging32_init_context(struct kvm_vcpu *vcpu)
1604 {
1605         struct kvm_mmu *context = &vcpu->arch.mmu;
1606
1607         context->new_cr3 = paging_new_cr3;
1608         context->page_fault = paging32_page_fault;
1609         context->gva_to_gpa = paging32_gva_to_gpa;
1610         context->free = paging_free;
1611         context->prefetch_page = paging32_prefetch_page;
1612         context->root_level = PT32_ROOT_LEVEL;
1613         context->shadow_root_level = PT32E_ROOT_LEVEL;
1614         context->root_hpa = INVALID_PAGE;
1615         return 0;
1616 }
1617
1618 static int paging32E_init_context(struct kvm_vcpu *vcpu)
1619 {
1620         return paging64_init_context_common(vcpu, PT32E_ROOT_LEVEL);
1621 }
1622
1623 static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
1624 {
1625         struct kvm_mmu *context = &vcpu->arch.mmu;
1626
1627         context->new_cr3 = nonpaging_new_cr3;
1628         context->page_fault = tdp_page_fault;
1629         context->free = nonpaging_free;
1630         context->prefetch_page = nonpaging_prefetch_page;
1631         context->shadow_root_level = kvm_x86_ops->get_tdp_level();
1632         context->root_hpa = INVALID_PAGE;
1633
1634         if (!is_paging(vcpu)) {
1635                 context->gva_to_gpa = nonpaging_gva_to_gpa;
1636                 context->root_level = 0;
1637         } else if (is_long_mode(vcpu)) {
1638                 context->gva_to_gpa = paging64_gva_to_gpa;
1639                 context->root_level = PT64_ROOT_LEVEL;
1640         } else if (is_pae(vcpu)) {
1641                 context->gva_to_gpa = paging64_gva_to_gpa;
1642                 context->root_level = PT32E_ROOT_LEVEL;
1643         } else {
1644                 context->gva_to_gpa = paging32_gva_to_gpa;
1645                 context->root_level = PT32_ROOT_LEVEL;
1646         }
1647
1648         return 0;
1649 }
1650
1651 static int init_kvm_softmmu(struct kvm_vcpu *vcpu)
1652 {
1653         ASSERT(vcpu);
1654         ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
1655
1656         if (!is_paging(vcpu))
1657                 return nonpaging_init_context(vcpu);
1658         else if (is_long_mode(vcpu))
1659                 return paging64_init_context(vcpu);
1660         else if (is_pae(vcpu))
1661                 return paging32E_init_context(vcpu);
1662         else
1663                 return paging32_init_context(vcpu);
1664 }
1665
1666 static int init_kvm_mmu(struct kvm_vcpu *vcpu)
1667 {
1668         vcpu->arch.update_pte.pfn = bad_pfn;
1669
1670         if (tdp_enabled)
1671                 return init_kvm_tdp_mmu(vcpu);
1672         else
1673                 return init_kvm_softmmu(vcpu);
1674 }
1675
1676 static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
1677 {
1678         ASSERT(vcpu);
1679         if (VALID_PAGE(vcpu->arch.mmu.root_hpa)) {
1680                 vcpu->arch.mmu.free(vcpu);
1681                 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
1682         }
1683 }
1684
1685 int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
1686 {
1687         destroy_kvm_mmu(vcpu);
1688         return init_kvm_mmu(vcpu);
1689 }
1690 EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
1691
1692 int kvm_mmu_load(struct kvm_vcpu *vcpu)
1693 {
1694         int r;
1695
1696         r = mmu_topup_memory_caches(vcpu);
1697         if (r)
1698                 goto out;
1699         spin_lock(&vcpu->kvm->mmu_lock);
1700         kvm_mmu_free_some_pages(vcpu);
1701         mmu_alloc_roots(vcpu);
1702         spin_unlock(&vcpu->kvm->mmu_lock);
1703         kvm_x86_ops->set_cr3(vcpu, vcpu->arch.mmu.root_hpa);
1704         kvm_mmu_flush_tlb(vcpu);
1705 out:
1706         return r;
1707 }
1708 EXPORT_SYMBOL_GPL(kvm_mmu_load);
1709
1710 void kvm_mmu_unload(struct kvm_vcpu *vcpu)
1711 {
1712         mmu_free_roots(vcpu);
1713 }
1714
1715 static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
1716                                   struct kvm_mmu_page *sp,
1717                                   u64 *spte)
1718 {
1719         u64 pte;
1720         struct kvm_mmu_page *child;
1721
1722         pte = *spte;
1723         if (is_shadow_present_pte(pte)) {
1724                 if (sp->role.level == PT_PAGE_TABLE_LEVEL ||
1725                     is_large_pte(pte))
1726                         rmap_remove(vcpu->kvm, spte);
1727                 else {
1728                         child = page_header(pte & PT64_BASE_ADDR_MASK);
1729                         mmu_page_remove_parent_pte(child, spte);
1730                 }
1731         }
1732         set_shadow_pte(spte, shadow_trap_nonpresent_pte);
1733         if (is_large_pte(pte))
1734                 --vcpu->kvm->stat.lpages;
1735 }
1736
1737 static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
1738                                   struct kvm_mmu_page *sp,
1739                                   u64 *spte,
1740                                   const void *new)
1741 {
1742         if (sp->role.level != PT_PAGE_TABLE_LEVEL) {
1743                 if (!vcpu->arch.update_pte.largepage ||
1744                     sp->role.glevels == PT32_ROOT_LEVEL) {
1745                         ++vcpu->kvm->stat.mmu_pde_zapped;
1746                         return;
1747                 }
1748         }
1749
1750         ++vcpu->kvm->stat.mmu_pte_updated;
1751         if (sp->role.glevels == PT32_ROOT_LEVEL)
1752                 paging32_update_pte(vcpu, sp, spte, new);
1753         else
1754                 paging64_update_pte(vcpu, sp, spte, new);
1755 }
1756
1757 static bool need_remote_flush(u64 old, u64 new)
1758 {
1759         if (!is_shadow_present_pte(old))
1760                 return false;
1761         if (!is_shadow_present_pte(new))
1762                 return true;
1763         if ((old ^ new) & PT64_BASE_ADDR_MASK)
1764                 return true;
1765         old ^= PT64_NX_MASK;
1766         new ^= PT64_NX_MASK;
1767         return (old & ~new & PT64_PERM_MASK) != 0;
1768 }
1769
1770 static void mmu_pte_write_flush_tlb(struct kvm_vcpu *vcpu, u64 old, u64 new)
1771 {
1772         if (need_remote_flush(old, new))
1773                 kvm_flush_remote_tlbs(vcpu->kvm);
1774         else
1775                 kvm_mmu_flush_tlb(vcpu);
1776 }
1777
1778 static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu)
1779 {
1780         u64 *spte = vcpu->arch.last_pte_updated;
1781
1782         return !!(spte && (*spte & shadow_accessed_mask));
1783 }
1784
1785 static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
1786                                           const u8 *new, int bytes)
1787 {
1788         gfn_t gfn;
1789         int r;
1790         u64 gpte = 0;
1791         pfn_t pfn;
1792
1793         vcpu->arch.update_pte.largepage = 0;
1794
1795         if (bytes != 4 && bytes != 8)
1796                 return;
1797
1798         /*
1799          * Assume that the pte write on a page table of the same type
1800          * as the current vcpu paging mode.  This is nearly always true
1801          * (might be false while changing modes).  Note it is verified later
1802          * by update_pte().
1803          */
1804         if (is_pae(vcpu)) {
1805                 /* Handle a 32-bit guest writing two halves of a 64-bit gpte */
1806                 if ((bytes == 4) && (gpa % 4 == 0)) {
1807                         r = kvm_read_guest(vcpu->kvm, gpa & ~(u64)7, &gpte, 8);
1808                         if (r)
1809                                 return;
1810                         memcpy((void *)&gpte + (gpa % 8), new, 4);
1811                 } else if ((bytes == 8) && (gpa % 8 == 0)) {
1812                         memcpy((void *)&gpte, new, 8);
1813                 }
1814         } else {
1815                 if ((bytes == 4) && (gpa % 4 == 0))
1816                         memcpy((void *)&gpte, new, 4);
1817         }
1818         if (!is_present_pte(gpte))
1819                 return;
1820         gfn = (gpte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
1821
1822         if (is_large_pte(gpte) && is_largepage_backed(vcpu, gfn)) {
1823                 gfn &= ~(KVM_PAGES_PER_HPAGE-1);
1824                 vcpu->arch.update_pte.largepage = 1;
1825         }
1826         vcpu->arch.update_pte.mmu_seq = vcpu->kvm->mmu_notifier_seq;
1827         smp_rmb();
1828         pfn = gfn_to_pfn(vcpu->kvm, gfn);
1829
1830         if (is_error_pfn(pfn)) {
1831                 kvm_release_pfn_clean(pfn);
1832                 return;
1833         }
1834         vcpu->arch.update_pte.gfn = gfn;
1835         vcpu->arch.update_pte.pfn = pfn;
1836 }
1837
1838 static void kvm_mmu_access_page(struct kvm_vcpu *vcpu, gfn_t gfn)
1839 {
1840         u64 *spte = vcpu->arch.last_pte_updated;
1841
1842         if (spte
1843             && vcpu->arch.last_pte_gfn == gfn
1844             && shadow_accessed_mask
1845             && !(*spte & shadow_accessed_mask)
1846             && is_shadow_present_pte(*spte))
1847                 set_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte);
1848 }
1849
1850 void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
1851                        const u8 *new, int bytes)
1852 {
1853         gfn_t gfn = gpa >> PAGE_SHIFT;
1854         struct kvm_mmu_page *sp;
1855         struct hlist_node *node, *n;
1856         struct hlist_head *bucket;
1857         unsigned index;
1858         u64 entry, gentry;
1859         u64 *spte;
1860         unsigned offset = offset_in_page(gpa);
1861         unsigned pte_size;
1862         unsigned page_offset;
1863         unsigned misaligned;
1864         unsigned quadrant;
1865         int level;
1866         int flooded = 0;
1867         int npte;
1868         int r;
1869
1870         pgprintk("%s: gpa %llx bytes %d\n", __func__, gpa, bytes);
1871         mmu_guess_page_from_pte_write(vcpu, gpa, new, bytes);
1872         spin_lock(&vcpu->kvm->mmu_lock);
1873         kvm_mmu_access_page(vcpu, gfn);
1874         kvm_mmu_free_some_pages(vcpu);
1875         ++vcpu->kvm->stat.mmu_pte_write;
1876         kvm_mmu_audit(vcpu, "pre pte write");
1877         if (gfn == vcpu->arch.last_pt_write_gfn
1878             && !last_updated_pte_accessed(vcpu)) {
1879                 ++vcpu->arch.last_pt_write_count;
1880                 if (vcpu->arch.last_pt_write_count >= 3)
1881                         flooded = 1;
1882         } else {
1883                 vcpu->arch.last_pt_write_gfn = gfn;
1884                 vcpu->arch.last_pt_write_count = 1;
1885                 vcpu->arch.last_pte_updated = NULL;
1886         }
1887         index = kvm_page_table_hashfn(gfn);
1888         bucket = &vcpu->kvm->arch.mmu_page_hash[index];
1889         hlist_for_each_entry_safe(sp, node, n, bucket, hash_link) {
1890                 if (sp->gfn != gfn || sp->role.metaphysical || sp->role.invalid)
1891                         continue;
1892                 pte_size = sp->role.glevels == PT32_ROOT_LEVEL ? 4 : 8;
1893                 misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
1894                 misaligned |= bytes < 4;
1895                 if (misaligned || flooded) {
1896                         /*
1897                          * Misaligned accesses are too much trouble to fix
1898                          * up; also, they usually indicate a page is not used
1899                          * as a page table.
1900                          *
1901                          * If we're seeing too many writes to a page,
1902                          * it may no longer be a page table, or we may be
1903                          * forking, in which case it is better to unmap the
1904                          * page.
1905                          */
1906                         pgprintk("misaligned: gpa %llx bytes %d role %x\n",
1907                                  gpa, bytes, sp->role.word);
1908                         kvm_mmu_zap_page(vcpu->kvm, sp);
1909                         ++vcpu->kvm->stat.mmu_flooded;
1910                         continue;
1911                 }
1912                 page_offset = offset;
1913                 level = sp->role.level;
1914                 npte = 1;
1915                 if (sp->role.glevels == PT32_ROOT_LEVEL) {
1916                         page_offset <<= 1;      /* 32->64 */
1917                         /*
1918                          * A 32-bit pde maps 4MB while the shadow pdes map
1919                          * only 2MB.  So we need to double the offset again
1920                          * and zap two pdes instead of one.
1921                          */
1922                         if (level == PT32_ROOT_LEVEL) {
1923                                 page_offset &= ~7; /* kill rounding error */
1924                                 page_offset <<= 1;
1925                                 npte = 2;
1926                         }
1927                         quadrant = page_offset >> PAGE_SHIFT;
1928                         page_offset &= ~PAGE_MASK;
1929                         if (quadrant != sp->role.quadrant)
1930                                 continue;
1931                 }
1932                 spte = &sp->spt[page_offset / sizeof(*spte)];
1933                 if ((gpa & (pte_size - 1)) || (bytes < pte_size)) {
1934                         gentry = 0;
1935                         r = kvm_read_guest_atomic(vcpu->kvm,
1936                                                   gpa & ~(u64)(pte_size - 1),
1937                                                   &gentry, pte_size);
1938                         new = (const void *)&gentry;
1939                         if (r < 0)
1940                                 new = NULL;
1941                 }
1942                 while (npte--) {
1943                         entry = *spte;
1944                         mmu_pte_write_zap_pte(vcpu, sp, spte);
1945                         if (new)
1946                                 mmu_pte_write_new_pte(vcpu, sp, spte, new);
1947                         mmu_pte_write_flush_tlb(vcpu, entry, *spte);
1948                         ++spte;
1949                 }
1950         }
1951         kvm_mmu_audit(vcpu, "post pte write");
1952         spin_unlock(&vcpu->kvm->mmu_lock);
1953         if (!is_error_pfn(vcpu->arch.update_pte.pfn)) {
1954                 kvm_release_pfn_clean(vcpu->arch.update_pte.pfn);
1955                 vcpu->arch.update_pte.pfn = bad_pfn;
1956         }
1957 }
1958
1959 int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
1960 {
1961         gpa_t gpa;
1962         int r;
1963
1964         gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva);
1965
1966         spin_lock(&vcpu->kvm->mmu_lock);
1967         r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
1968         spin_unlock(&vcpu->kvm->mmu_lock);
1969         return r;
1970 }
1971 EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page_virt);
1972
1973 void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
1974 {
1975         while (vcpu->kvm->arch.n_free_mmu_pages < KVM_REFILL_PAGES) {
1976                 struct kvm_mmu_page *sp;
1977
1978                 sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev,
1979                                   struct kvm_mmu_page, link);
1980                 kvm_mmu_zap_page(vcpu->kvm, sp);
1981                 ++vcpu->kvm->stat.mmu_recycled;
1982         }
1983 }
1984
1985 int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code)
1986 {
1987         int r;
1988         enum emulation_result er;
1989
1990         r = vcpu->arch.mmu.page_fault(vcpu, cr2, error_code);
1991         if (r < 0)
1992                 goto out;
1993
1994         if (!r) {
1995                 r = 1;
1996                 goto out;
1997         }
1998
1999         r = mmu_topup_memory_caches(vcpu);
2000         if (r)
2001                 goto out;
2002
2003         er = emulate_instruction(vcpu, vcpu->run, cr2, error_code, 0);
2004
2005         switch (er) {
2006         case EMULATE_DONE:
2007                 return 1;
2008         case EMULATE_DO_MMIO:
2009                 ++vcpu->stat.mmio_exits;
2010                 return 0;
2011         case EMULATE_FAIL:
2012                 kvm_report_emulation_failure(vcpu, "pagetable");
2013                 return 1;
2014         default:
2015                 BUG();
2016         }
2017 out:
2018         return r;
2019 }
2020 EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);
2021
2022 void kvm_enable_tdp(void)
2023 {
2024         tdp_enabled = true;
2025 }
2026 EXPORT_SYMBOL_GPL(kvm_enable_tdp);
2027
2028 void kvm_disable_tdp(void)
2029 {
2030         tdp_enabled = false;
2031 }
2032 EXPORT_SYMBOL_GPL(kvm_disable_tdp);
2033
2034 static void free_mmu_pages(struct kvm_vcpu *vcpu)
2035 {
2036         struct kvm_mmu_page *sp;
2037
2038         while (!list_empty(&vcpu->kvm->arch.active_mmu_pages)) {
2039                 sp = container_of(vcpu->kvm->arch.active_mmu_pages.next,
2040                                   struct kvm_mmu_page, link);
2041                 kvm_mmu_zap_page(vcpu->kvm, sp);
2042                 cond_resched();
2043         }
2044         free_page((unsigned long)vcpu->arch.mmu.pae_root);
2045 }
2046
2047 static int alloc_mmu_pages(struct kvm_vcpu *vcpu)
2048 {
2049         struct page *page;
2050         int i;
2051
2052         ASSERT(vcpu);
2053
2054         if (vcpu->kvm->arch.n_requested_mmu_pages)
2055                 vcpu->kvm->arch.n_free_mmu_pages =
2056                                         vcpu->kvm->arch.n_requested_mmu_pages;
2057         else
2058                 vcpu->kvm->arch.n_free_mmu_pages =
2059                                         vcpu->kvm->arch.n_alloc_mmu_pages;
2060         /*
2061          * When emulating 32-bit mode, cr3 is only 32 bits even on x86_64.
2062          * Therefore we need to allocate shadow page tables in the first
2063          * 4GB of memory, which happens to fit the DMA32 zone.
2064          */
2065         page = alloc_page(GFP_KERNEL | __GFP_DMA32);
2066         if (!page)
2067                 goto error_1;
2068         vcpu->arch.mmu.pae_root = page_address(page);
2069         for (i = 0; i < 4; ++i)
2070                 vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
2071
2072         return 0;
2073
2074 error_1:
2075         free_mmu_pages(vcpu);
2076         return -ENOMEM;
2077 }
2078
2079 int kvm_mmu_create(struct kvm_vcpu *vcpu)
2080 {
2081         ASSERT(vcpu);
2082         ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
2083
2084         return alloc_mmu_pages(vcpu);
2085 }
2086
2087 int kvm_mmu_setup(struct kvm_vcpu *vcpu)
2088 {
2089         ASSERT(vcpu);
2090         ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
2091
2092         return init_kvm_mmu(vcpu);
2093 }
2094
2095 void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
2096 {
2097         ASSERT(vcpu);
2098
2099         destroy_kvm_mmu(vcpu);
2100         free_mmu_pages(vcpu);
2101         mmu_free_memory_caches(vcpu);
2102 }
2103
2104 void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
2105 {
2106         struct kvm_mmu_page *sp;
2107
2108         spin_lock(&kvm->mmu_lock);
2109         list_for_each_entry(sp, &kvm->arch.active_mmu_pages, link) {
2110                 int i;
2111                 u64 *pt;
2112
2113                 if (!test_bit(slot, &sp->slot_bitmap))
2114                         continue;
2115
2116                 pt = sp->spt;
2117                 for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
2118                         /* avoid RMW */
2119                         if (pt[i] & PT_WRITABLE_MASK)
2120                                 pt[i] &= ~PT_WRITABLE_MASK;
2121         }
2122         kvm_flush_remote_tlbs(kvm);
2123         spin_unlock(&kvm->mmu_lock);
2124 }
2125
2126 void kvm_mmu_zap_all(struct kvm *kvm)
2127 {
2128         struct kvm_mmu_page *sp, *node;
2129
2130         spin_lock(&kvm->mmu_lock);
2131         list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link)
2132                 kvm_mmu_zap_page(kvm, sp);
2133         spin_unlock(&kvm->mmu_lock);
2134
2135         kvm_flush_remote_tlbs(kvm);
2136 }
2137
2138 static void kvm_mmu_remove_one_alloc_mmu_page(struct kvm *kvm)
2139 {
2140         struct kvm_mmu_page *page;
2141
2142         page = container_of(kvm->arch.active_mmu_pages.prev,
2143                             struct kvm_mmu_page, link);
2144         kvm_mmu_zap_page(kvm, page);
2145 }
2146
2147 static int mmu_shrink(int nr_to_scan, gfp_t gfp_mask)
2148 {
2149         struct kvm *kvm;
2150         struct kvm *kvm_freed = NULL;
2151         int cache_count = 0;
2152
2153         spin_lock(&kvm_lock);
2154
2155         list_for_each_entry(kvm, &vm_list, vm_list) {
2156                 int npages;
2157
2158                 if (!down_read_trylock(&kvm->slots_lock))
2159                         continue;
2160                 spin_lock(&kvm->mmu_lock);
2161                 npages = kvm->arch.n_alloc_mmu_pages -
2162                          kvm->arch.n_free_mmu_pages;
2163                 cache_count += npages;
2164                 if (!kvm_freed && nr_to_scan > 0 && npages > 0) {
2165                         kvm_mmu_remove_one_alloc_mmu_page(kvm);
2166                         cache_count--;
2167                         kvm_freed = kvm;
2168                 }
2169                 nr_to_scan--;
2170
2171                 spin_unlock(&kvm->mmu_lock);
2172                 up_read(&kvm->slots_lock);
2173         }
2174         if (kvm_freed)
2175                 list_move_tail(&kvm_freed->vm_list, &vm_list);
2176
2177         spin_unlock(&kvm_lock);
2178
2179         return cache_count;
2180 }
2181
2182 static struct shrinker mmu_shrinker = {
2183         .shrink = mmu_shrink,
2184         .seeks = DEFAULT_SEEKS * 10,
2185 };
2186
2187 static void mmu_destroy_caches(void)
2188 {
2189         if (pte_chain_cache)
2190                 kmem_cache_destroy(pte_chain_cache);
2191         if (rmap_desc_cache)
2192                 kmem_cache_destroy(rmap_desc_cache);
2193         if (mmu_page_header_cache)
2194                 kmem_cache_destroy(mmu_page_header_cache);
2195 }
2196
2197 void kvm_mmu_module_exit(void)
2198 {
2199         mmu_destroy_caches();
2200         unregister_shrinker(&mmu_shrinker);
2201 }
2202
2203 int kvm_mmu_module_init(void)
2204 {
2205         pte_chain_cache = kmem_cache_create("kvm_pte_chain",
2206                                             sizeof(struct kvm_pte_chain),
2207                                             0, 0, NULL);
2208         if (!pte_chain_cache)
2209                 goto nomem;
2210         rmap_desc_cache = kmem_cache_create("kvm_rmap_desc",
2211                                             sizeof(struct kvm_rmap_desc),
2212                                             0, 0, NULL);
2213         if (!rmap_desc_cache)
2214                 goto nomem;
2215
2216         mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
2217                                                   sizeof(struct kvm_mmu_page),
2218                                                   0, 0, NULL);
2219         if (!mmu_page_header_cache)
2220                 goto nomem;
2221
2222         register_shrinker(&mmu_shrinker);
2223
2224         return 0;
2225
2226 nomem:
2227         mmu_destroy_caches();
2228         return -ENOMEM;
2229 }
2230
2231 /*
2232  * Caculate mmu pages needed for kvm.
2233  */
2234 unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
2235 {
2236         int i;
2237         unsigned int nr_mmu_pages;
2238         unsigned int  nr_pages = 0;
2239
2240         for (i = 0; i < kvm->nmemslots; i++)
2241                 nr_pages += kvm->memslots[i].npages;
2242
2243         nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000;
2244         nr_mmu_pages = max(nr_mmu_pages,
2245                         (unsigned int) KVM_MIN_ALLOC_MMU_PAGES);
2246
2247         return nr_mmu_pages;
2248 }
2249
2250 static void *pv_mmu_peek_buffer(struct kvm_pv_mmu_op_buffer *buffer,
2251                                 unsigned len)
2252 {
2253         if (len > buffer->len)
2254                 return NULL;
2255         return buffer->ptr;
2256 }
2257
2258 static void *pv_mmu_read_buffer(struct kvm_pv_mmu_op_buffer *buffer,
2259                                 unsigned len)
2260 {
2261         void *ret;
2262
2263         ret = pv_mmu_peek_buffer(buffer, len);
2264         if (!ret)
2265                 return ret;
2266         buffer->ptr += len;
2267         buffer->len -= len;
2268         buffer->processed += len;
2269         return ret;
2270 }
2271
2272 static int kvm_pv_mmu_write(struct kvm_vcpu *vcpu,
2273                              gpa_t addr, gpa_t value)
2274 {
2275         int bytes = 8;
2276         int r;
2277
2278         if (!is_long_mode(vcpu) && !is_pae(vcpu))
2279                 bytes = 4;
2280
2281         r = mmu_topup_memory_caches(vcpu);
2282         if (r)
2283                 return r;
2284
2285         if (!emulator_write_phys(vcpu, addr, &value, bytes))
2286                 return -EFAULT;
2287
2288         return 1;
2289 }
2290
2291 static int kvm_pv_mmu_flush_tlb(struct kvm_vcpu *vcpu)
2292 {
2293         kvm_x86_ops->tlb_flush(vcpu);
2294         return 1;
2295 }
2296
2297 static int kvm_pv_mmu_release_pt(struct kvm_vcpu *vcpu, gpa_t addr)
2298 {
2299         spin_lock(&vcpu->kvm->mmu_lock);
2300         mmu_unshadow(vcpu->kvm, addr >> PAGE_SHIFT);
2301         spin_unlock(&vcpu->kvm->mmu_lock);
2302         return 1;
2303 }
2304
2305 static int kvm_pv_mmu_op_one(struct kvm_vcpu *vcpu,
2306                              struct kvm_pv_mmu_op_buffer *buffer)
2307 {
2308         struct kvm_mmu_op_header *header;
2309
2310         header = pv_mmu_peek_buffer(buffer, sizeof *header);
2311         if (!header)
2312                 return 0;
2313         switch (header->op) {
2314         case KVM_MMU_OP_WRITE_PTE: {
2315                 struct kvm_mmu_op_write_pte *wpte;
2316
2317                 wpte = pv_mmu_read_buffer(buffer, sizeof *wpte);
2318                 if (!wpte)
2319                         return 0;
2320                 return kvm_pv_mmu_write(vcpu, wpte->pte_phys,
2321                                         wpte->pte_val);
2322         }
2323         case KVM_MMU_OP_FLUSH_TLB: {
2324                 struct kvm_mmu_op_flush_tlb *ftlb;
2325
2326                 ftlb = pv_mmu_read_buffer(buffer, sizeof *ftlb);
2327                 if (!ftlb)
2328                         return 0;
2329                 return kvm_pv_mmu_flush_tlb(vcpu);
2330         }
2331         case KVM_MMU_OP_RELEASE_PT: {
2332                 struct kvm_mmu_op_release_pt *rpt;
2333
2334                 rpt = pv_mmu_read_buffer(buffer, sizeof *rpt);
2335                 if (!rpt)
2336                         return 0;
2337                 return kvm_pv_mmu_release_pt(vcpu, rpt->pt_phys);
2338         }
2339         default: return 0;
2340         }
2341 }
2342
2343 int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes,
2344                   gpa_t addr, unsigned long *ret)
2345 {
2346         int r;
2347         struct kvm_pv_mmu_op_buffer *buffer = &vcpu->arch.mmu_op_buffer;
2348
2349         buffer->ptr = buffer->buf;
2350         buffer->len = min_t(unsigned long, bytes, sizeof buffer->buf);
2351         buffer->processed = 0;
2352
2353         r = kvm_read_guest(vcpu->kvm, addr, buffer->buf, buffer->len);
2354         if (r)
2355                 goto out;
2356
2357         while (buffer->len) {
2358                 r = kvm_pv_mmu_op_one(vcpu, buffer);
2359                 if (r < 0)
2360                         goto out;
2361                 if (r == 0)
2362                         break;
2363         }
2364
2365         r = 1;
2366 out:
2367         *ret = buffer->processed;
2368         return r;
2369 }
2370
2371 #ifdef AUDIT
2372
2373 static const char *audit_msg;
2374
2375 static gva_t canonicalize(gva_t gva)
2376 {
2377 #ifdef CONFIG_X86_64
2378         gva = (long long)(gva << 16) >> 16;
2379 #endif
2380         return gva;
2381 }
2382
2383 static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
2384                                 gva_t va, int level)
2385 {
2386         u64 *pt = __va(page_pte & PT64_BASE_ADDR_MASK);
2387         int i;
2388         gva_t va_delta = 1ul << (PAGE_SHIFT + 9 * (level - 1));
2389
2390         for (i = 0; i < PT64_ENT_PER_PAGE; ++i, va += va_delta) {
2391                 u64 ent = pt[i];
2392
2393                 if (ent == shadow_trap_nonpresent_pte)
2394                         continue;
2395
2396                 va = canonicalize(va);
2397                 if (level > 1) {
2398                         if (ent == shadow_notrap_nonpresent_pte)
2399                                 printk(KERN_ERR "audit: (%s) nontrapping pte"
2400                                        " in nonleaf level: levels %d gva %lx"
2401                                        " level %d pte %llx\n", audit_msg,
2402                                        vcpu->arch.mmu.root_level, va, level, ent);
2403
2404                         audit_mappings_page(vcpu, ent, va, level - 1);
2405                 } else {
2406                         gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, va);
2407                         hpa_t hpa = (hpa_t)gpa_to_pfn(vcpu, gpa) << PAGE_SHIFT;
2408
2409                         if (is_shadow_present_pte(ent)
2410                             && (ent & PT64_BASE_ADDR_MASK) != hpa)
2411                                 printk(KERN_ERR "xx audit error: (%s) levels %d"
2412                                        " gva %lx gpa %llx hpa %llx ent %llx %d\n",
2413                                        audit_msg, vcpu->arch.mmu.root_level,
2414                                        va, gpa, hpa, ent,
2415                                        is_shadow_present_pte(ent));
2416                         else if (ent == shadow_notrap_nonpresent_pte
2417                                  && !is_error_hpa(hpa))
2418                                 printk(KERN_ERR "audit: (%s) notrap shadow,"
2419                                        " valid guest gva %lx\n", audit_msg, va);
2420                         kvm_release_pfn_clean(pfn);
2421
2422                 }
2423         }
2424 }
2425
2426 static void audit_mappings(struct kvm_vcpu *vcpu)
2427 {
2428         unsigned i;
2429
2430         if (vcpu->arch.mmu.root_level == 4)
2431                 audit_mappings_page(vcpu, vcpu->arch.mmu.root_hpa, 0, 4);
2432         else
2433                 for (i = 0; i < 4; ++i)
2434                         if (vcpu->arch.mmu.pae_root[i] & PT_PRESENT_MASK)
2435                                 audit_mappings_page(vcpu,
2436                                                     vcpu->arch.mmu.pae_root[i],
2437                                                     i << 30,
2438                                                     2);
2439 }
2440
2441 static int count_rmaps(struct kvm_vcpu *vcpu)
2442 {
2443         int nmaps = 0;
2444         int i, j, k;
2445
2446         for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
2447                 struct kvm_memory_slot *m = &vcpu->kvm->memslots[i];
2448                 struct kvm_rmap_desc *d;
2449
2450                 for (j = 0; j < m->npages; ++j) {
2451                         unsigned long *rmapp = &m->rmap[j];
2452
2453                         if (!*rmapp)
2454                                 continue;
2455                         if (!(*rmapp & 1)) {
2456                                 ++nmaps;
2457                                 continue;
2458                         }
2459                         d = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
2460                         while (d) {
2461                                 for (k = 0; k < RMAP_EXT; ++k)
2462                                         if (d->shadow_ptes[k])
2463                                                 ++nmaps;
2464                                         else
2465                                                 break;
2466                                 d = d->more;
2467                         }
2468                 }
2469         }
2470         return nmaps;
2471 }
2472
2473 static int count_writable_mappings(struct kvm_vcpu *vcpu)
2474 {
2475         int nmaps = 0;
2476         struct kvm_mmu_page *sp;
2477         int i;
2478
2479         list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
2480                 u64 *pt = sp->spt;
2481
2482                 if (sp->role.level != PT_PAGE_TABLE_LEVEL)
2483                         continue;
2484
2485                 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
2486                         u64 ent = pt[i];
2487
2488                         if (!(ent & PT_PRESENT_MASK))
2489                                 continue;
2490                         if (!(ent & PT_WRITABLE_MASK))
2491                                 continue;
2492                         ++nmaps;
2493                 }
2494         }
2495         return nmaps;
2496 }
2497
2498 static void audit_rmap(struct kvm_vcpu *vcpu)
2499 {
2500         int n_rmap = count_rmaps(vcpu);
2501         int n_actual = count_writable_mappings(vcpu);
2502
2503         if (n_rmap != n_actual)
2504                 printk(KERN_ERR "%s: (%s) rmap %d actual %d\n",
2505                        __func__, audit_msg, n_rmap, n_actual);
2506 }
2507
2508 static void audit_write_protection(struct kvm_vcpu *vcpu)
2509 {
2510         struct kvm_mmu_page *sp;
2511         struct kvm_memory_slot *slot;
2512         unsigned long *rmapp;
2513         gfn_t gfn;
2514
2515         list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
2516                 if (sp->role.metaphysical)
2517                         continue;
2518
2519                 slot = gfn_to_memslot(vcpu->kvm, sp->gfn);
2520                 gfn = unalias_gfn(vcpu->kvm, sp->gfn);
2521                 rmapp = &slot->rmap[gfn - slot->base_gfn];
2522                 if (*rmapp)
2523                         printk(KERN_ERR "%s: (%s) shadow page has writable"
2524                                " mappings: gfn %lx role %x\n",
2525                                __func__, audit_msg, sp->gfn,
2526                                sp->role.word);
2527         }
2528 }
2529
2530 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg)
2531 {
2532         int olddbg = dbg;
2533
2534         dbg = 0;
2535         audit_msg = msg;
2536         audit_rmap(vcpu);
2537         audit_write_protection(vcpu);
2538         audit_mappings(vcpu);
2539         dbg = olddbg;
2540 }
2541
2542 #endif