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
  31 #include <asm/page.h>
  32 #include <asm/cmpxchg.h>
  33 #include <asm/io.h>
  34
  35 #undef MMU_DEBUG
  36
  37 #undef AUDIT
  38
  39 #ifdef AUDIT
  40 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg);
  41 #else
  42 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg) {}
  43 #endif
  44
  45 #ifdef MMU_DEBUG
  46
  47 #define pgprintk(x...) do { if (dbg) printk(x); } while (0)
  48 #define rmap_printk(x...) do { if (dbg) printk(x); } while (0)
  49
  50 #else
  51
  52 #define pgprintk(x...) do { } while (0)
  53 #define rmap_printk(x...) do { } while (0)
  54
  55 #endif
  56
  57 #if defined(MMU_DEBUG) || defined(AUDIT)
  58 static int dbg = 1;
  59 #endif
  60
  61 #ifndef MMU_DEBUG
  62 #define ASSERT(x) do { } while (0)
  63 #else
  64 #define ASSERT(x)                                                       \
  65         if (!(x)) {                                                     \
  66                 printk(KERN_WARNING "assertion failed %s:%d: %s\n",     \
  67                        __FILE__, __LINE__, #x);                         \
  68         }
  69 #endif
  70
  71 #define PT64_PT_BITS 9
  72 #define PT64_ENT_PER_PAGE (1 << PT64_PT_BITS)
  73 #define PT32_PT_BITS 10
  74 #define PT32_ENT_PER_PAGE (1 << PT32_PT_BITS)
  75
  76 #define PT_WRITABLE_SHIFT 1
  77
  78 #define PT_PRESENT_MASK (1ULL << 0)
  79 #define PT_WRITABLE_MASK (1ULL << PT_WRITABLE_SHIFT)
  80 #define PT_USER_MASK (1ULL << 2)
  81 #define PT_PWT_MASK (1ULL << 3)
  82 #define PT_PCD_MASK (1ULL << 4)
  83 #define PT_ACCESSED_MASK (1ULL << 5)
  84 #define PT_DIRTY_MASK (1ULL << 6)
  85 #define PT_PAGE_SIZE_MASK (1ULL << 7)
  86 #define PT_PAT_MASK (1ULL << 7)
  87 #define PT_GLOBAL_MASK (1ULL << 8)
  88 #define PT64_NX_SHIFT 63
  89 #define PT64_NX_MASK (1ULL << PT64_NX_SHIFT)
  90
  91 #define PT_PAT_SHIFT 7
  92 #define PT_DIR_PAT_SHIFT 12
  93 #define PT_DIR_PAT_MASK (1ULL << PT_DIR_PAT_SHIFT)
  94
  95 #define PT32_DIR_PSE36_SIZE 4
  96 #define PT32_DIR_PSE36_SHIFT 13
  97 #define PT32_DIR_PSE36_MASK \
  98         (((1ULL << PT32_DIR_PSE36_SIZE) - 1) << PT32_DIR_PSE36_SHIFT)
  99
 100
 101 #define PT_FIRST_AVAIL_BITS_SHIFT 9
 102 #define PT64_SECOND_AVAIL_BITS_SHIFT 52
 103
 104 #define PT_SHADOW_IO_MARK (1ULL << PT_FIRST_AVAIL_BITS_SHIFT)
 105
 106 #define VALID_PAGE(x) ((x) != INVALID_PAGE)
 107
 108 #define PT64_LEVEL_BITS 9
 109
 110 #define PT64_LEVEL_SHIFT(level) \
 111                 (PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS)
 112
 113 #define PT64_LEVEL_MASK(level) \
 114                 (((1ULL << PT64_LEVEL_BITS) - 1) << PT64_LEVEL_SHIFT(level))
 115
 116 #define PT64_INDEX(address, level)\
 117         (((address) >> PT64_LEVEL_SHIFT(level)) & ((1 << PT64_LEVEL_BITS) - 1))
 118
 119
 120 #define PT32_LEVEL_BITS 10
 121
 122 #define PT32_LEVEL_SHIFT(level) \
 123                 (PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS)
 124
 125 #define PT32_LEVEL_MASK(level) \
 126                 (((1ULL << PT32_LEVEL_BITS) - 1) << PT32_LEVEL_SHIFT(level))
 127
 128 #define PT32_INDEX(address, level)\
 129         (((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))
 130
 131
 132 #define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))
 133 #define PT64_DIR_BASE_ADDR_MASK \
 134         (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))
 135
 136 #define PT32_BASE_ADDR_MASK PAGE_MASK
 137 #define PT32_DIR_BASE_ADDR_MASK \
 138         (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
 139
 140 #define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK \
 141                         | PT64_NX_MASK)
 142
 143 #define PFERR_PRESENT_MASK (1U << 0)
 144 #define PFERR_WRITE_MASK (1U << 1)
 145 #define PFERR_USER_MASK (1U << 2)
 146 #define PFERR_FETCH_MASK (1U << 4)
 147
 148 #define PT64_ROOT_LEVEL 4
 149 #define PT32_ROOT_LEVEL 2
 150 #define PT32E_ROOT_LEVEL 3
 151
 152 #define PT_DIRECTORY_LEVEL 2
 153 #define PT_PAGE_TABLE_LEVEL 1
 154
 155 #define RMAP_EXT 4
 156
 157 #define ACC_EXEC_MASK    1
 158 #define ACC_WRITE_MASK   PT_WRITABLE_MASK
 159 #define ACC_USER_MASK    PT_USER_MASK
 160 #define ACC_ALL          (ACC_EXEC_MASK | ACC_WRITE_MASK | ACC_USER_MASK)
 161
 162 struct kvm_rmap_desc {
 163         u64 *shadow_ptes[RMAP_EXT];
 164         struct kvm_rmap_desc *more;
 165 };
 166
 167 static struct kmem_cache *pte_chain_cache;
 168 static struct kmem_cache *rmap_desc_cache;
 169 static struct kmem_cache *mmu_page_header_cache;
 170
 171 static u64 __read_mostly shadow_trap_nonpresent_pte;
 172 static u64 __read_mostly shadow_notrap_nonpresent_pte;
 173
 174 void kvm_mmu_set_nonpresent_ptes(u64 trap_pte, u64 notrap_pte)
 175 {
 176         shadow_trap_nonpresent_pte = trap_pte;
 177         shadow_notrap_nonpresent_pte = notrap_pte;
 178 }
 179 EXPORT_SYMBOL_GPL(kvm_mmu_set_nonpresent_ptes);
 180
 181 static int is_write_protection(struct kvm_vcpu *vcpu)
 182 {
 183         return vcpu->arch.cr0 & X86_CR0_WP;
 184 }
 185
 186 static int is_cpuid_PSE36(void)
 187 {
 188         return 1;
 189 }
 190
 191 static int is_nx(struct kvm_vcpu *vcpu)
 192 {
 193         return vcpu->arch.shadow_efer & EFER_NX;
 194 }
 195
 196 static int is_present_pte(unsigned long pte)
 197 {
 198         return pte & PT_PRESENT_MASK;
 199 }
 200
 201 static int is_shadow_present_pte(u64 pte)
 202 {
 203         pte &= ~PT_SHADOW_IO_MARK;
 204         return pte != shadow_trap_nonpresent_pte
 205                 && pte != shadow_notrap_nonpresent_pte;
 206 }
 207
 208 static int is_writeble_pte(unsigned long pte)
 209 {
 210         return pte & PT_WRITABLE_MASK;
 211 }
 212
 213 static int is_dirty_pte(unsigned long pte)
 214 {
 215         return pte & PT_DIRTY_MASK;
 216 }
 217
 218 static int is_io_pte(unsigned long pte)
 219 {
 220         return pte & PT_SHADOW_IO_MARK;
 221 }
 222
 223 static int is_rmap_pte(u64 pte)
 224 {
 225         return is_shadow_present_pte(pte);
 226 }
 227
 228 static gfn_t pse36_gfn_delta(u32 gpte)
 229 {
 230         int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT;
 231
 232         return (gpte & PT32_DIR_PSE36_MASK) << shift;
 233 }
 234
 235 static void set_shadow_pte(u64 *sptep, u64 spte)
 236 {
 237 #ifdef CONFIG_X86_64
 238         set_64bit((unsigned long *)sptep, spte);
 239 #else
 240         set_64bit((unsigned long long *)sptep, spte);
 241 #endif
 242 }
 243
 244 static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
 245                                   struct kmem_cache *base_cache, int min)
 246 {
 247         void *obj;
 248
 249         if (cache->nobjs >= min)
 250                 return 0;
 251         while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
 252                 obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
 253                 if (!obj)
 254                         return -ENOMEM;
 255                 cache->objects[cache->nobjs++] = obj;
 256         }
 257         return 0;
 258 }
 259
 260 static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
 261 {
 262         while (mc->nobjs)
 263                 kfree(mc->objects[--mc->nobjs]);
 264 }
 265
 266 static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
 267                                        int min)
 268 {
 269         struct page *page;
 270
 271         if (cache->nobjs >= min)
 272                 return 0;
 273         while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
 274                 page = alloc_page(GFP_KERNEL);
 275                 if (!page)
 276                         return -ENOMEM;
 277                 set_page_private(page, 0);
 278                 cache->objects[cache->nobjs++] = page_address(page);
 279         }
 280         return 0;
 281 }
 282
 283 static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
 284 {
 285         while (mc->nobjs)
 286                 free_page((unsigned long)mc->objects[--mc->nobjs]);
 287 }
 288
 289 static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
 290 {
 291         int r;
 292
 293         r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_chain_cache,
 294                                    pte_chain_cache, 4);
 295         if (r)
 296                 goto out;
 297         r = mmu_topup_memory_cache(&vcpu->arch.mmu_rmap_desc_cache,
 298                                    rmap_desc_cache, 1);
 299         if (r)
 300                 goto out;
 301         r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
 302         if (r)
 303                 goto out;
 304         r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
 305                                    mmu_page_header_cache, 4);
 306 out:
 307         return r;
 308 }
 309
 310 static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
 311 {
 312         mmu_free_memory_cache(&vcpu->arch.mmu_pte_chain_cache);
 313         mmu_free_memory_cache(&vcpu->arch.mmu_rmap_desc_cache);
 314         mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache);
 315         mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache);
 316 }
 317
 318 static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc,
 319                                     size_t size)
 320 {
 321         void *p;
 322
 323         BUG_ON(!mc->nobjs);
 324         p = mc->objects[--mc->nobjs];
 325         memset(p, 0, size);
 326         return p;
 327 }
 328
 329 static struct kvm_pte_chain *mmu_alloc_pte_chain(struct kvm_vcpu *vcpu)
 330 {
 331         return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_chain_cache,
 332                                       sizeof(struct kvm_pte_chain));
 333 }
 334
 335 static void mmu_free_pte_chain(struct kvm_pte_chain *pc)
 336 {
 337         kfree(pc);
 338 }
 339
 340 static struct kvm_rmap_desc *mmu_alloc_rmap_desc(struct kvm_vcpu *vcpu)
 341 {
 342         return mmu_memory_cache_alloc(&vcpu->arch.mmu_rmap_desc_cache,
 343                                       sizeof(struct kvm_rmap_desc));
 344 }
 345
 346 static void mmu_free_rmap_desc(struct kvm_rmap_desc *rd)
 347 {
 348         kfree(rd);
 349 }
 350
 351 /*
 352  * Take gfn and return the reverse mapping to it.
 353  * Note: gfn must be unaliased before this function get called
 354  */
 355
 356 static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn)
 357 {
 358         struct kvm_memory_slot *slot;
 359
 360         slot = gfn_to_memslot(kvm, gfn);
 361         return &slot->rmap[gfn - slot->base_gfn];
 362 }
 363
 364 /*
 365  * Reverse mapping data structures:
 366  *
 367  * If rmapp bit zero is zero, then rmapp point to the shadw page table entry
 368  * that points to page_address(page).
 369  *
 370  * If rmapp bit zero is one, (then rmap & ~1) points to a struct kvm_rmap_desc
 371  * containing more mappings.
 372  */
 373 static void rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn)
 374 {
 375         struct kvm_mmu_page *sp;
 376         struct kvm_rmap_desc *desc;
 377         unsigned long *rmapp;
 378         int i;
 379
 380         if (!is_rmap_pte(*spte))
 381                 return;
 382         gfn = unalias_gfn(vcpu->kvm, gfn);
 383         sp = page_header(__pa(spte));
 384         sp->gfns[spte - sp->spt] = gfn;
 385         rmapp = gfn_to_rmap(vcpu->kvm, gfn);
 386         if (!*rmapp) {
 387                 rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte);
 388                 *rmapp = (unsigned long)spte;
 389         } else if (!(*rmapp & 1)) {
 390                 rmap_printk("rmap_add: %p %llx 1->many\n", spte, *spte);
 391                 desc = mmu_alloc_rmap_desc(vcpu);
 392                 desc->shadow_ptes[0] = (u64 *)*rmapp;
 393                 desc->shadow_ptes[1] = spte;
 394                 *rmapp = (unsigned long)desc | 1;
 395         } else {
 396                 rmap_printk("rmap_add: %p %llx many->many\n", spte, *spte);
 397                 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
 398                 while (desc->shadow_ptes[RMAP_EXT-1] && desc->more)
 399                         desc = desc->more;
 400                 if (desc->shadow_ptes[RMAP_EXT-1]) {
 401                         desc->more = mmu_alloc_rmap_desc(vcpu);
 402                         desc = desc->more;
 403                 }
 404                 for (i = 0; desc->shadow_ptes[i]; ++i)
 405                         ;
 406                 desc->shadow_ptes[i] = spte;
 407         }
 408 }
 409
 410 static void rmap_desc_remove_entry(unsigned long *rmapp,
 411                                    struct kvm_rmap_desc *desc,
 412                                    int i,
 413                                    struct kvm_rmap_desc *prev_desc)
 414 {
 415         int j;
 416
 417         for (j = RMAP_EXT - 1; !desc->shadow_ptes[j] && j > i; --j)
 418                 ;
 419         desc->shadow_ptes[i] = desc->shadow_ptes[j];
 420         desc->shadow_ptes[j] = NULL;
 421         if (j != 0)
 422                 return;
 423         if (!prev_desc && !desc->more)
 424                 *rmapp = (unsigned long)desc->shadow_ptes[0];
 425         else
 426                 if (prev_desc)
 427                         prev_desc->more = desc->more;
 428                 else
 429                         *rmapp = (unsigned long)desc->more | 1;
 430         mmu_free_rmap_desc(desc);
 431 }
 432
 433 static void rmap_remove(struct kvm *kvm, u64 *spte)
 434 {
 435         struct kvm_rmap_desc *desc;
 436         struct kvm_rmap_desc *prev_desc;
 437         struct kvm_mmu_page *sp;
 438         struct page *page;
 439         unsigned long *rmapp;
 440         int i;
 441
 442         if (!is_rmap_pte(*spte))
 443                 return;
 444         sp = page_header(__pa(spte));
 445         page = pfn_to_page((*spte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT);
 446         mark_page_accessed(page);
 447         if (is_writeble_pte(*spte))
 448                 kvm_release_page_dirty(page);
 449         else
 450                 kvm_release_page_clean(page);
 451         rmapp = gfn_to_rmap(kvm, sp->gfns[spte - sp->spt]);
 452         if (!*rmapp) {
 453                 printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte);
 454                 BUG();
 455         } else if (!(*rmapp & 1)) {
 456                 rmap_printk("rmap_remove:  %p %llx 1->0\n", spte, *spte);
 457                 if ((u64 *)*rmapp != spte) {
 458                         printk(KERN_ERR "rmap_remove:  %p %llx 1->BUG\n",
 459                                spte, *spte);
 460                         BUG();
 461                 }
 462                 *rmapp = 0;
 463         } else {
 464                 rmap_printk("rmap_remove:  %p %llx many->many\n", spte, *spte);
 465                 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
 466                 prev_desc = NULL;
 467                 while (desc) {
 468                         for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i)
 469                                 if (desc->shadow_ptes[i] == spte) {
 470                                         rmap_desc_remove_entry(rmapp,
 471                                                                desc, i,
 472                                                                prev_desc);
 473                                         return;
 474                                 }
 475                         prev_desc = desc;
 476                         desc = desc->more;
 477                 }
 478                 BUG();
 479         }
 480 }
 481
 482 static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte)
 483 {
 484         struct kvm_rmap_desc *desc;
 485         struct kvm_rmap_desc *prev_desc;
 486         u64 *prev_spte;
 487         int i;
 488
 489         if (!*rmapp)
 490                 return NULL;
 491         else if (!(*rmapp & 1)) {
 492                 if (!spte)
 493                         return (u64 *)*rmapp;
 494                 return NULL;
 495         }
 496         desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
 497         prev_desc = NULL;
 498         prev_spte = NULL;
 499         while (desc) {
 500                 for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i) {
 501                         if (prev_spte == spte)
 502                                 return desc->shadow_ptes[i];
 503                         prev_spte = desc->shadow_ptes[i];
 504                 }
 505                 desc = desc->more;
 506         }
 507         return NULL;
 508 }
 509
 510 static void rmap_write_protect(struct kvm *kvm, u64 gfn)
 511 {
 512         unsigned long *rmapp;
 513         u64 *spte;
 514         int write_protected = 0;
 515
 516         gfn = unalias_gfn(kvm, gfn);
 517         rmapp = gfn_to_rmap(kvm, gfn);
 518
 519         spte = rmap_next(kvm, rmapp, NULL);
 520         while (spte) {
 521                 BUG_ON(!spte);
 522                 BUG_ON(!(*spte & PT_PRESENT_MASK));
 523                 rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
 524                 if (is_writeble_pte(*spte)) {
 525                         set_shadow_pte(spte, *spte & ~PT_WRITABLE_MASK);
 526                         write_protected = 1;
 527                 }
 528                 spte = rmap_next(kvm, rmapp, spte);
 529         }
 530         if (write_protected)
 531                 kvm_flush_remote_tlbs(kvm);
 532 }
 533
 534 #ifdef MMU_DEBUG
 535 static int is_empty_shadow_page(u64 *spt)
 536 {
 537         u64 *pos;
 538         u64 *end;
 539
 540         for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
 541                 if ((*pos & ~PT_SHADOW_IO_MARK) != shadow_trap_nonpresent_pte) {
 542                         printk(KERN_ERR "%s: %p %llx\n", __FUNCTION__,
 543                                pos, *pos);
 544                         return 0;
 545                 }
 546         return 1;
 547 }
 548 #endif
 549
 550 static void kvm_mmu_free_page(struct kvm *kvm, struct kvm_mmu_page *sp)
 551 {
 552         ASSERT(is_empty_shadow_page(sp->spt));
 553         list_del(&sp->link);
 554         __free_page(virt_to_page(sp->spt));
 555         __free_page(virt_to_page(sp->gfns));
 556         kfree(sp);
 557         ++kvm->arch.n_free_mmu_pages;
 558 }
 559
 560 static unsigned kvm_page_table_hashfn(gfn_t gfn)
 561 {
 562         return gfn;
 563 }
 564
 565 static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
 566                                                u64 *parent_pte)
 567 {
 568         struct kvm_mmu_page *sp;
 569
 570         sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache, sizeof *sp);
 571         sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
 572         sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
 573         set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
 574         list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
 575         ASSERT(is_empty_shadow_page(sp->spt));
 576         sp->slot_bitmap = 0;
 577         sp->multimapped = 0;
 578         sp->parent_pte = parent_pte;
 579         --vcpu->kvm->arch.n_free_mmu_pages;
 580         return sp;
 581 }
 582
 583 static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
 584                                     struct kvm_mmu_page *sp, u64 *parent_pte)
 585 {
 586         struct kvm_pte_chain *pte_chain;
 587         struct hlist_node *node;
 588         int i;
 589
 590         if (!parent_pte)
 591                 return;
 592         if (!sp->multimapped) {
 593                 u64 *old = sp->parent_pte;
 594
 595                 if (!old) {
 596                         sp->parent_pte = parent_pte;
 597                         return;
 598                 }
 599                 sp->multimapped = 1;
 600                 pte_chain = mmu_alloc_pte_chain(vcpu);
 601                 INIT_HLIST_HEAD(&sp->parent_ptes);
 602                 hlist_add_head(&pte_chain->link, &sp->parent_ptes);
 603                 pte_chain->parent_ptes[0] = old;
 604         }
 605         hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link) {
 606                 if (pte_chain->parent_ptes[NR_PTE_CHAIN_ENTRIES-1])
 607                         continue;
 608                 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i)
 609                         if (!pte_chain->parent_ptes[i]) {
 610                                 pte_chain->parent_ptes[i] = parent_pte;
 611                                 return;
 612                         }
 613         }
 614         pte_chain = mmu_alloc_pte_chain(vcpu);
 615         BUG_ON(!pte_chain);
 616         hlist_add_head(&pte_chain->link, &sp->parent_ptes);
 617         pte_chain->parent_ptes[0] = parent_pte;
 618 }
 619
 620 static void mmu_page_remove_parent_pte(struct kvm_mmu_page *sp,
 621                                        u64 *parent_pte)
 622 {
 623         struct kvm_pte_chain *pte_chain;
 624         struct hlist_node *node;
 625         int i;
 626
 627         if (!sp->multimapped) {
 628                 BUG_ON(sp->parent_pte != parent_pte);
 629                 sp->parent_pte = NULL;
 630                 return;
 631         }
 632         hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
 633                 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
 634                         if (!pte_chain->parent_ptes[i])
 635                                 break;
 636                         if (pte_chain->parent_ptes[i] != parent_pte)
 637                                 continue;
 638                         while (i + 1 < NR_PTE_CHAIN_ENTRIES
 639                                 && pte_chain->parent_ptes[i + 1]) {
 640                                 pte_chain->parent_ptes[i]
 641                                         = pte_chain->parent_ptes[i + 1];
 642                                 ++i;
 643                         }
 644                         pte_chain->parent_ptes[i] = NULL;
 645                         if (i == 0) {
 646                                 hlist_del(&pte_chain->link);
 647                                 mmu_free_pte_chain(pte_chain);
 648                                 if (hlist_empty(&sp->parent_ptes)) {
 649                                         sp->multimapped = 0;
 650                                         sp->parent_pte = NULL;
 651                                 }
 652                         }
 653                         return;
 654                 }
 655         BUG();
 656 }
 657
 658 static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm *kvm, gfn_t gfn)
 659 {
 660         unsigned index;
 661         struct hlist_head *bucket;
 662         struct kvm_mmu_page *sp;
 663         struct hlist_node *node;
 664
 665         pgprintk("%s: looking for gfn %lx\n", __FUNCTION__, gfn);
 666         index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
 667         bucket = &kvm->arch.mmu_page_hash[index];
 668         hlist_for_each_entry(sp, node, bucket, hash_link)
 669                 if (sp->gfn == gfn && !sp->role.metaphysical) {
 670                         pgprintk("%s: found role %x\n",
 671                                  __FUNCTION__, sp->role.word);
 672                         return sp;
 673                 }
 674         return NULL;
 675 }
 676
 677 static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
 678                                              gfn_t gfn,
 679                                              gva_t gaddr,
 680                                              unsigned level,
 681                                              int metaphysical,
 682                                              unsigned access,
 683                                              u64 *parent_pte)
 684 {
 685         union kvm_mmu_page_role role;
 686         unsigned index;
 687         unsigned quadrant;
 688         struct hlist_head *bucket;
 689         struct kvm_mmu_page *sp;
 690         struct hlist_node *node;
 691
 692         role.word = 0;
 693         role.glevels = vcpu->arch.mmu.root_level;
 694         role.level = level;
 695         role.metaphysical = metaphysical;
 696         role.access = access;
 697         if (vcpu->arch.mmu.root_level <= PT32_ROOT_LEVEL) {
 698                 quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
 699                 quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
 700                 role.quadrant = quadrant;
 701         }
 702         pgprintk("%s: looking gfn %lx role %x\n", __FUNCTION__,
 703                  gfn, role.word);
 704         index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
 705         bucket = &vcpu->kvm->arch.mmu_page_hash[index];
 706         hlist_for_each_entry(sp, node, bucket, hash_link)
 707                 if (sp->gfn == gfn && sp->role.word == role.word) {
 708                         mmu_page_add_parent_pte(vcpu, sp, parent_pte);
 709                         pgprintk("%s: found\n", __FUNCTION__);
 710                         return sp;
 711                 }
 712         ++vcpu->kvm->stat.mmu_cache_miss;
 713         sp = kvm_mmu_alloc_page(vcpu, parent_pte);
 714         if (!sp)
 715                 return sp;
 716         pgprintk("%s: adding gfn %lx role %x\n", __FUNCTION__, gfn, role.word);
 717         sp->gfn = gfn;
 718         sp->role = role;
 719         hlist_add_head(&sp->hash_link, bucket);
 720         vcpu->arch.mmu.prefetch_page(vcpu, sp);
 721         if (!metaphysical)
 722                 rmap_write_protect(vcpu->kvm, gfn);
 723         return sp;
 724 }
 725
 726 static void kvm_mmu_page_unlink_children(struct kvm *kvm,
 727                                          struct kvm_mmu_page *sp)
 728 {
 729         unsigned i;
 730         u64 *pt;
 731         u64 ent;
 732
 733         pt = sp->spt;
 734
 735         if (sp->role.level == PT_PAGE_TABLE_LEVEL) {
 736                 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
 737                         if (is_shadow_present_pte(pt[i]))
 738                                 rmap_remove(kvm, &pt[i]);
 739                         pt[i] = shadow_trap_nonpresent_pte;
 740                 }
 741                 kvm_flush_remote_tlbs(kvm);
 742                 return;
 743         }
 744
 745         for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
 746                 ent = pt[i];
 747
 748                 pt[i] = shadow_trap_nonpresent_pte;
 749                 if (!is_shadow_present_pte(ent))
 750                         continue;
 751                 ent &= PT64_BASE_ADDR_MASK;
 752                 mmu_page_remove_parent_pte(page_header(ent), &pt[i]);
 753         }
 754         kvm_flush_remote_tlbs(kvm);
 755 }
 756
 757 static void kvm_mmu_put_page(struct kvm_mmu_page *sp, u64 *parent_pte)
 758 {
 759         mmu_page_remove_parent_pte(sp, parent_pte);
 760 }
 761
 762 static void kvm_mmu_reset_last_pte_updated(struct kvm *kvm)
 763 {
 764         int i;
 765
 766         for (i = 0; i < KVM_MAX_VCPUS; ++i)
 767                 if (kvm->vcpus[i])
 768                         kvm->vcpus[i]->arch.last_pte_updated = NULL;
 769 }
 770
 771 static void kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp)
 772 {
 773         u64 *parent_pte;
 774
 775         ++kvm->stat.mmu_shadow_zapped;
 776         while (sp->multimapped || sp->parent_pte) {
 777                 if (!sp->multimapped)
 778                         parent_pte = sp->parent_pte;
 779                 else {
 780                         struct kvm_pte_chain *chain;
 781
 782                         chain = container_of(sp->parent_ptes.first,
 783                                              struct kvm_pte_chain, link);
 784                         parent_pte = chain->parent_ptes[0];
 785                 }
 786                 BUG_ON(!parent_pte);
 787                 kvm_mmu_put_page(sp, parent_pte);
 788                 set_shadow_pte(parent_pte, shadow_trap_nonpresent_pte);
 789         }
 790         kvm_mmu_page_unlink_children(kvm, sp);
 791         if (!sp->root_count) {
 792                 hlist_del(&sp->hash_link);
 793                 kvm_mmu_free_page(kvm, sp);
 794         } else
 795                 list_move(&sp->link, &kvm->arch.active_mmu_pages);
 796         kvm_mmu_reset_last_pte_updated(kvm);
 797 }
 798
 799 /*
 800  * Changing the number of mmu pages allocated to the vm
 801  * Note: if kvm_nr_mmu_pages is too small, you will get dead lock
 802  */
 803 void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages)
 804 {
 805         /*
 806          * If we set the number of mmu pages to be smaller be than the
 807          * number of actived pages , we must to free some mmu pages before we
 808          * change the value
 809          */
 810
 811         if ((kvm->arch.n_alloc_mmu_pages - kvm->arch.n_free_mmu_pages) >
 812             kvm_nr_mmu_pages) {
 813                 int n_used_mmu_pages = kvm->arch.n_alloc_mmu_pages
 814                                        - kvm->arch.n_free_mmu_pages;
 815
 816                 while (n_used_mmu_pages > kvm_nr_mmu_pages) {
 817                         struct kvm_mmu_page *page;
 818
 819                         page = container_of(kvm->arch.active_mmu_pages.prev,
 820                                             struct kvm_mmu_page, link);
 821                         kvm_mmu_zap_page(kvm, page);
 822                         n_used_mmu_pages--;
 823                 }
 824                 kvm->arch.n_free_mmu_pages = 0;
 825         }
 826         else
 827                 kvm->arch.n_free_mmu_pages += kvm_nr_mmu_pages
 828                                          - kvm->arch.n_alloc_mmu_pages;
 829
 830         kvm->arch.n_alloc_mmu_pages = kvm_nr_mmu_pages;
 831 }
 832
 833 static int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
 834 {
 835         unsigned index;
 836         struct hlist_head *bucket;
 837         struct kvm_mmu_page *sp;
 838         struct hlist_node *node, *n;
 839         int r;
 840
 841         pgprintk("%s: looking for gfn %lx\n", __FUNCTION__, gfn);
 842         r = 0;
 843         index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
 844         bucket = &kvm->arch.mmu_page_hash[index];
 845         hlist_for_each_entry_safe(sp, node, n, bucket, hash_link)
 846                 if (sp->gfn == gfn && !sp->role.metaphysical) {
 847                         pgprintk("%s: gfn %lx role %x\n", __FUNCTION__, gfn,
 848                                  sp->role.word);
 849                         kvm_mmu_zap_page(kvm, sp);
 850                         r = 1;
 851                 }
 852         return r;
 853 }
 854
 855 static void mmu_unshadow(struct kvm *kvm, gfn_t gfn)
 856 {
 857         struct kvm_mmu_page *sp;
 858
 859         while ((sp = kvm_mmu_lookup_page(kvm, gfn)) != NULL) {
 860                 pgprintk("%s: zap %lx %x\n", __FUNCTION__, gfn, sp->role.word);
 861                 kvm_mmu_zap_page(kvm, sp);
 862         }
 863 }
 864
 865 static void page_header_update_slot(struct kvm *kvm, void *pte, gfn_t gfn)
 866 {
 867         int slot = memslot_id(kvm, gfn_to_memslot(kvm, gfn));
 868         struct kvm_mmu_page *sp = page_header(__pa(pte));
 869
 870         __set_bit(slot, &sp->slot_bitmap);
 871 }
 872
 873 struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva)
 874 {
 875         struct page *page;
 876
 877         gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva);
 878
 879         if (gpa == UNMAPPED_GVA)
 880                 return NULL;
 881
 882         down_read(&current->mm->mmap_sem);
 883         page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);
 884         up_read(&current->mm->mmap_sem);
 885
 886         return page;
 887 }
 888
 889 static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
 890                          unsigned pt_access, unsigned pte_access,
 891                          int user_fault, int write_fault, int dirty,
 892                          int *ptwrite, gfn_t gfn, struct page *page)
 893 {
 894         u64 spte;
 895         int was_rmapped = is_rmap_pte(*shadow_pte);
 896         int was_writeble = is_writeble_pte(*shadow_pte);
 897
 898         pgprintk("%s: spte %llx access %x write_fault %d"
 899                  " user_fault %d gfn %lx\n",
 900                  __FUNCTION__, *shadow_pte, pt_access,
 901                  write_fault, user_fault, gfn);
 902
 903         /*
 904          * We don't set the accessed bit, since we sometimes want to see
 905          * whether the guest actually used the pte (in order to detect
 906          * demand paging).
 907          */
 908         spte = PT_PRESENT_MASK | PT_DIRTY_MASK;
 909         if (!dirty)
 910                 pte_access &= ~ACC_WRITE_MASK;
 911         if (!(pte_access & ACC_EXEC_MASK))
 912                 spte |= PT64_NX_MASK;
 913
 914         spte |= PT_PRESENT_MASK;
 915         if (pte_access & ACC_USER_MASK)
 916                 spte |= PT_USER_MASK;
 917
 918         if (is_error_page(page)) {
 919                 set_shadow_pte(shadow_pte,
 920                                shadow_trap_nonpresent_pte | PT_SHADOW_IO_MARK);
 921                 kvm_release_page_clean(page);
 922                 return;
 923         }
 924
 925         spte |= page_to_phys(page);
 926
 927         if ((pte_access & ACC_WRITE_MASK)
 928             || (write_fault && !is_write_protection(vcpu) && !user_fault)) {
 929                 struct kvm_mmu_page *shadow;
 930
 931                 spte |= PT_WRITABLE_MASK;
 932                 if (user_fault) {
 933                         mmu_unshadow(vcpu->kvm, gfn);
 934                         goto unshadowed;
 935                 }
 936
 937                 shadow = kvm_mmu_lookup_page(vcpu->kvm, gfn);
 938                 if (shadow) {
 939                         pgprintk("%s: found shadow page for %lx, marking ro\n",
 940                                  __FUNCTION__, gfn);
 941                         pte_access &= ~ACC_WRITE_MASK;
 942                         if (is_writeble_pte(spte)) {
 943                                 spte &= ~PT_WRITABLE_MASK;
 944                                 kvm_x86_ops->tlb_flush(vcpu);
 945                         }
 946                         if (write_fault)
 947                                 *ptwrite = 1;
 948                 }
 949         }
 950
 951 unshadowed:
 952
 953         if (pte_access & ACC_WRITE_MASK)
 954                 mark_page_dirty(vcpu->kvm, gfn);
 955
 956         pgprintk("%s: setting spte %llx\n", __FUNCTION__, spte);
 957         set_shadow_pte(shadow_pte, spte);
 958         page_header_update_slot(vcpu->kvm, shadow_pte, gfn);
 959         if (!was_rmapped) {
 960                 rmap_add(vcpu, shadow_pte, gfn);
 961                 if (!is_rmap_pte(*shadow_pte))
 962                         kvm_release_page_clean(page);
 963         } else {
 964                 if (was_writeble)
 965                         kvm_release_page_dirty(page);
 966                 else
 967                         kvm_release_page_clean(page);
 968         }
 969         if (!ptwrite || !*ptwrite)
 970                 vcpu->arch.last_pte_updated = shadow_pte;
 971 }
 972
 973 static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
 974 {
 975 }
 976
 977 static int __nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write,
 978                            gfn_t gfn, struct page *page)
 979 {
 980         int level = PT32E_ROOT_LEVEL;
 981         hpa_t table_addr = vcpu->arch.mmu.root_hpa;
 982         int pt_write = 0;
 983
 984         for (; ; level--) {
 985                 u32 index = PT64_INDEX(v, level);
 986                 u64 *table;
 987
 988                 ASSERT(VALID_PAGE(table_addr));
 989                 table = __va(table_addr);
 990
 991                 if (level == 1) {
 992                         mmu_set_spte(vcpu, &table[index], ACC_ALL, ACC_ALL,
 993                                      0, write, 1, &pt_write, gfn, page);
 994                         return pt_write || is_io_pte(table[index]);
 995                 }
 996
 997                 if (table[index] == shadow_trap_nonpresent_pte) {
 998                         struct kvm_mmu_page *new_table;
 999                         gfn_t pseudo_gfn;
1000
1001                         pseudo_gfn = (v & PT64_DIR_BASE_ADDR_MASK)
1002                                 >> PAGE_SHIFT;
1003                         new_table = kvm_mmu_get_page(vcpu, pseudo_gfn,
1004                                                      v, level - 1,
1005                                                      1, ACC_ALL, &table[index]);
1006                         if (!new_table) {
1007                                 pgprintk("nonpaging_map: ENOMEM\n");
1008                                 kvm_release_page_clean(page);
1009                                 return -ENOMEM;
1010                         }
1011
1012                         table[index] = __pa(new_table->spt) | PT_PRESENT_MASK
1013                                 | PT_WRITABLE_MASK | PT_USER_MASK;
1014                 }
1015                 table_addr = table[index] & PT64_BASE_ADDR_MASK;
1016         }
1017 }
1018
1019 static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
1020 {
1021         int r;
1022
1023         struct page *page;
1024
1025         down_read(&vcpu->kvm->slots_lock);
1026
1027         down_read(&current->mm->mmap_sem);
1028         page = gfn_to_page(vcpu->kvm, gfn);
1029         up_read(&current->mm->mmap_sem);
1030
1031         spin_lock(&vcpu->kvm->mmu_lock);
1032         kvm_mmu_free_some_pages(vcpu);
1033         r = __nonpaging_map(vcpu, v, write, gfn, page);
1034         spin_unlock(&vcpu->kvm->mmu_lock);
1035
1036         up_read(&vcpu->kvm->slots_lock);
1037
1038         return r;
1039 }
1040
1041
1042 static void nonpaging_prefetch_page(struct kvm_vcpu *vcpu,
1043                                     struct kvm_mmu_page *sp)
1044 {
1045         int i;
1046
1047         for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
1048                 sp->spt[i] = shadow_trap_nonpresent_pte;
1049 }
1050
1051 static void mmu_free_roots(struct kvm_vcpu *vcpu)
1052 {
1053         int i;
1054         struct kvm_mmu_page *sp;
1055
1056         if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
1057                 return;
1058         spin_lock(&vcpu->kvm->mmu_lock);
1059 #ifdef CONFIG_X86_64
1060         if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
1061                 hpa_t root = vcpu->arch.mmu.root_hpa;
1062
1063                 sp = page_header(root);
1064                 --sp->root_count;
1065                 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
1066                 spin_unlock(&vcpu->kvm->mmu_lock);
1067                 return;
1068         }
1069 #endif
1070         for (i = 0; i < 4; ++i) {
1071                 hpa_t root = vcpu->arch.mmu.pae_root[i];
1072
1073                 if (root) {
1074                         root &= PT64_BASE_ADDR_MASK;
1075                         sp = page_header(root);
1076                         --sp->root_count;
1077                 }
1078                 vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
1079         }
1080         spin_unlock(&vcpu->kvm->mmu_lock);
1081         vcpu->arch.mmu.root_hpa = INVALID_PAGE;
1082 }
1083
1084 static void mmu_alloc_roots(struct kvm_vcpu *vcpu)
1085 {
1086         int i;
1087         gfn_t root_gfn;
1088         struct kvm_mmu_page *sp;
1089
1090         root_gfn = vcpu->arch.cr3 >> PAGE_SHIFT;
1091
1092 #ifdef CONFIG_X86_64
1093         if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
1094                 hpa_t root = vcpu->arch.mmu.root_hpa;
1095
1096                 ASSERT(!VALID_PAGE(root));
1097                 sp = kvm_mmu_get_page(vcpu, root_gfn, 0,
1098                                       PT64_ROOT_LEVEL, 0, ACC_ALL, NULL);
1099                 root = __pa(sp->spt);
1100                 ++sp->root_count;
1101                 vcpu->arch.mmu.root_hpa = root;
1102                 return;
1103         }
1104 #endif
1105         for (i = 0; i < 4; ++i) {
1106                 hpa_t root = vcpu->arch.mmu.pae_root[i];
1107
1108                 ASSERT(!VALID_PAGE(root));
1109                 if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
1110                         if (!is_present_pte(vcpu->arch.pdptrs[i])) {
1111                                 vcpu->arch.mmu.pae_root[i] = 0;
1112                                 continue;
1113                         }
1114                         root_gfn = vcpu->arch.pdptrs[i] >> PAGE_SHIFT;
1115                 } else if (vcpu->arch.mmu.root_level == 0)
1116                         root_gfn = 0;
1117                 sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
1118                                       PT32_ROOT_LEVEL, !is_paging(vcpu),
1119                                       ACC_ALL, NULL);
1120                 root = __pa(sp->spt);
1121                 ++sp->root_count;
1122                 vcpu->arch.mmu.pae_root[i] = root | PT_PRESENT_MASK;
1123         }
1124         vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
1125 }
1126
1127 static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr)
1128 {
1129         return vaddr;
1130 }
1131
1132 static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
1133                                 u32 error_code)
1134 {
1135         gfn_t gfn;
1136         int r;
1137
1138         pgprintk("%s: gva %lx error %x\n", __FUNCTION__, gva, error_code);
1139         r = mmu_topup_memory_caches(vcpu);
1140         if (r)
1141                 return r;
1142
1143         ASSERT(vcpu);
1144         ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
1145
1146         gfn = gva >> PAGE_SHIFT;
1147
1148         return nonpaging_map(vcpu, gva & PAGE_MASK,
1149                              error_code & PFERR_WRITE_MASK, gfn);
1150 }
1151
1152 static void nonpaging_free(struct kvm_vcpu *vcpu)
1153 {
1154         mmu_free_roots(vcpu);
1155 }
1156
1157 static int nonpaging_init_context(struct kvm_vcpu *vcpu)
1158 {
1159         struct kvm_mmu *context = &vcpu->arch.mmu;
1160
1161         context->new_cr3 = nonpaging_new_cr3;
1162         context->page_fault = nonpaging_page_fault;
1163         context->gva_to_gpa = nonpaging_gva_to_gpa;
1164         context->free = nonpaging_free;
1165         context->prefetch_page = nonpaging_prefetch_page;
1166         context->root_level = 0;
1167         context->shadow_root_level = PT32E_ROOT_LEVEL;
1168         context->root_hpa = INVALID_PAGE;
1169         return 0;
1170 }
1171
1172 void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
1173 {
1174         ++vcpu->stat.tlb_flush;
1175         kvm_x86_ops->tlb_flush(vcpu);
1176 }
1177
1178 static void paging_new_cr3(struct kvm_vcpu *vcpu)
1179 {
1180         pgprintk("%s: cr3 %lx\n", __FUNCTION__, vcpu->arch.cr3);
1181         mmu_free_roots(vcpu);
1182 }
1183
1184 static void inject_page_fault(struct kvm_vcpu *vcpu,
1185                               u64 addr,
1186                               u32 err_code)
1187 {
1188         kvm_inject_page_fault(vcpu, addr, err_code);
1189 }
1190
1191 static void paging_free(struct kvm_vcpu *vcpu)
1192 {
1193         nonpaging_free(vcpu);
1194 }
1195
1196 #define PTTYPE 64
1197 #include "paging_tmpl.h"
1198 #undef PTTYPE
1199
1200 #define PTTYPE 32
1201 #include "paging_tmpl.h"
1202 #undef PTTYPE
1203
1204 static int paging64_init_context_common(struct kvm_vcpu *vcpu, int level)
1205 {
1206         struct kvm_mmu *context = &vcpu->arch.mmu;
1207
1208         ASSERT(is_pae(vcpu));
1209         context->new_cr3 = paging_new_cr3;
1210         context->page_fault = paging64_page_fault;
1211         context->gva_to_gpa = paging64_gva_to_gpa;
1212         context->prefetch_page = paging64_prefetch_page;
1213         context->free = paging_free;
1214         context->root_level = level;
1215         context->shadow_root_level = level;
1216         context->root_hpa = INVALID_PAGE;
1217         return 0;
1218 }
1219
1220 static int paging64_init_context(struct kvm_vcpu *vcpu)
1221 {
1222         return paging64_init_context_common(vcpu, PT64_ROOT_LEVEL);
1223 }
1224
1225 static int paging32_init_context(struct kvm_vcpu *vcpu)
1226 {
1227         struct kvm_mmu *context = &vcpu->arch.mmu;
1228
1229         context->new_cr3 = paging_new_cr3;
1230         context->page_fault = paging32_page_fault;
1231         context->gva_to_gpa = paging32_gva_to_gpa;
1232         context->free = paging_free;
1233         context->prefetch_page = paging32_prefetch_page;
1234         context->root_level = PT32_ROOT_LEVEL;
1235         context->shadow_root_level = PT32E_ROOT_LEVEL;
1236         context->root_hpa = INVALID_PAGE;
1237         return 0;
1238 }
1239
1240 static int paging32E_init_context(struct kvm_vcpu *vcpu)
1241 {
1242         return paging64_init_context_common(vcpu, PT32E_ROOT_LEVEL);
1243 }
1244
1245 static int init_kvm_mmu(struct kvm_vcpu *vcpu)
1246 {
1247         ASSERT(vcpu);
1248         ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
1249
1250         if (!is_paging(vcpu))
1251                 return nonpaging_init_context(vcpu);
1252         else if (is_long_mode(vcpu))
1253                 return paging64_init_context(vcpu);
1254         else if (is_pae(vcpu))
1255                 return paging32E_init_context(vcpu);
1256         else
1257                 return paging32_init_context(vcpu);
1258 }
1259
1260 static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
1261 {
1262         ASSERT(vcpu);
1263         if (VALID_PAGE(vcpu->arch.mmu.root_hpa)) {
1264                 vcpu->arch.mmu.free(vcpu);
1265                 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
1266         }
1267 }
1268
1269 int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
1270 {
1271         destroy_kvm_mmu(vcpu);
1272         return init_kvm_mmu(vcpu);
1273 }
1274 EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
1275
1276 int kvm_mmu_load(struct kvm_vcpu *vcpu)
1277 {
1278         int r;
1279
1280         r = mmu_topup_memory_caches(vcpu);
1281         if (r)
1282                 goto out;
1283         spin_lock(&vcpu->kvm->mmu_lock);
1284         kvm_mmu_free_some_pages(vcpu);
1285         mmu_alloc_roots(vcpu);
1286         spin_unlock(&vcpu->kvm->mmu_lock);
1287         kvm_x86_ops->set_cr3(vcpu, vcpu->arch.mmu.root_hpa);
1288         kvm_mmu_flush_tlb(vcpu);
1289 out:
1290         return r;
1291 }
1292 EXPORT_SYMBOL_GPL(kvm_mmu_load);
1293
1294 void kvm_mmu_unload(struct kvm_vcpu *vcpu)
1295 {
1296         mmu_free_roots(vcpu);
1297 }
1298
1299 static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
1300                                   struct kvm_mmu_page *sp,
1301                                   u64 *spte)
1302 {
1303         u64 pte;
1304         struct kvm_mmu_page *child;
1305
1306         pte = *spte;
1307         if (is_shadow_present_pte(pte)) {
1308                 if (sp->role.level == PT_PAGE_TABLE_LEVEL)
1309                         rmap_remove(vcpu->kvm, spte);
1310                 else {
1311                         child = page_header(pte & PT64_BASE_ADDR_MASK);
1312                         mmu_page_remove_parent_pte(child, spte);
1313                 }
1314         }
1315         set_shadow_pte(spte, shadow_trap_nonpresent_pte);
1316 }
1317
1318 static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
1319                                   struct kvm_mmu_page *sp,
1320                                   u64 *spte,
1321                                   const void *new, int bytes,
1322                                   int offset_in_pte)
1323 {
1324         if (sp->role.level != PT_PAGE_TABLE_LEVEL) {
1325                 ++vcpu->kvm->stat.mmu_pde_zapped;
1326                 return;
1327         }
1328
1329         ++vcpu->kvm->stat.mmu_pte_updated;
1330         if (sp->role.glevels == PT32_ROOT_LEVEL)
1331                 paging32_update_pte(vcpu, sp, spte, new, bytes, offset_in_pte);
1332         else
1333                 paging64_update_pte(vcpu, sp, spte, new, bytes, offset_in_pte);
1334 }
1335
1336 static bool need_remote_flush(u64 old, u64 new)
1337 {
1338         if (!is_shadow_present_pte(old))
1339                 return false;
1340         if (!is_shadow_present_pte(new))
1341                 return true;
1342         if ((old ^ new) & PT64_BASE_ADDR_MASK)
1343                 return true;
1344         old ^= PT64_NX_MASK;
1345         new ^= PT64_NX_MASK;
1346         return (old & ~new & PT64_PERM_MASK) != 0;
1347 }
1348
1349 static void mmu_pte_write_flush_tlb(struct kvm_vcpu *vcpu, u64 old, u64 new)
1350 {
1351         if (need_remote_flush(old, new))
1352                 kvm_flush_remote_tlbs(vcpu->kvm);
1353         else
1354                 kvm_mmu_flush_tlb(vcpu);
1355 }
1356
1357 static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu)
1358 {
1359         u64 *spte = vcpu->arch.last_pte_updated;
1360
1361         return !!(spte && (*spte & PT_ACCESSED_MASK));
1362 }
1363
1364 static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
1365                                           const u8 *new, int bytes)
1366 {
1367         gfn_t gfn;
1368         int r;
1369         u64 gpte = 0;
1370         struct page *page;
1371
1372         if (bytes != 4 && bytes != 8)
1373                 return;
1374
1375         /*
1376          * Assume that the pte write on a page table of the same type
1377          * as the current vcpu paging mode.  This is nearly always true
1378          * (might be false while changing modes).  Note it is verified later
1379          * by update_pte().
1380          */
1381         if (is_pae(vcpu)) {
1382                 /* Handle a 32-bit guest writing two halves of a 64-bit gpte */
1383                 if ((bytes == 4) && (gpa % 4 == 0)) {
1384                         r = kvm_read_guest(vcpu->kvm, gpa & ~(u64)7, &gpte, 8);
1385                         if (r)
1386                                 return;
1387                         memcpy((void *)&gpte + (gpa % 8), new, 4);
1388                 } else if ((bytes == 8) && (gpa % 8 == 0)) {
1389                         memcpy((void *)&gpte, new, 8);
1390                 }
1391         } else {
1392                 if ((bytes == 4) && (gpa % 4 == 0))
1393                         memcpy((void *)&gpte, new, 4);
1394         }
1395         if (!is_present_pte(gpte))
1396                 return;
1397         gfn = (gpte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
1398
1399         down_read(&current->mm->mmap_sem);
1400         page = gfn_to_page(vcpu->kvm, gfn);
1401         up_read(&current->mm->mmap_sem);
1402
1403         vcpu->arch.update_pte.gfn = gfn;
1404         vcpu->arch.update_pte.page = gfn_to_page(vcpu->kvm, gfn);
1405 }
1406
1407 void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
1408                        const u8 *new, int bytes)
1409 {
1410         gfn_t gfn = gpa >> PAGE_SHIFT;
1411         struct kvm_mmu_page *sp;
1412         struct hlist_node *node, *n;
1413         struct hlist_head *bucket;
1414         unsigned index;
1415         u64 entry;
1416         u64 *spte;
1417         unsigned offset = offset_in_page(gpa);
1418         unsigned pte_size;
1419         unsigned page_offset;
1420         unsigned misaligned;
1421         unsigned quadrant;
1422         int level;
1423         int flooded = 0;
1424         int npte;
1425
1426         pgprintk("%s: gpa %llx bytes %d\n", __FUNCTION__, gpa, bytes);
1427         mmu_guess_page_from_pte_write(vcpu, gpa, new, bytes);
1428         spin_lock(&vcpu->kvm->mmu_lock);
1429         kvm_mmu_free_some_pages(vcpu);
1430         ++vcpu->kvm->stat.mmu_pte_write;
1431         kvm_mmu_audit(vcpu, "pre pte write");
1432         if (gfn == vcpu->arch.last_pt_write_gfn
1433             && !last_updated_pte_accessed(vcpu)) {
1434                 ++vcpu->arch.last_pt_write_count;
1435                 if (vcpu->arch.last_pt_write_count >= 3)
1436                         flooded = 1;
1437         } else {
1438                 vcpu->arch.last_pt_write_gfn = gfn;
1439                 vcpu->arch.last_pt_write_count = 1;
1440                 vcpu->arch.last_pte_updated = NULL;
1441         }
1442         index = kvm_page_table_hashfn(gfn) % KVM_NUM_MMU_PAGES;
1443         bucket = &vcpu->kvm->arch.mmu_page_hash[index];
1444         hlist_for_each_entry_safe(sp, node, n, bucket, hash_link) {
1445                 if (sp->gfn != gfn || sp->role.metaphysical)
1446                         continue;
1447                 pte_size = sp->role.glevels == PT32_ROOT_LEVEL ? 4 : 8;
1448                 misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
1449                 misaligned |= bytes < 4;
1450                 if (misaligned || flooded) {
1451                         /*
1452                          * Misaligned accesses are too much trouble to fix
1453                          * up; also, they usually indicate a page is not used
1454                          * as a page table.
1455                          *
1456                          * If we're seeing too many writes to a page,
1457                          * it may no longer be a page table, or we may be
1458                          * forking, in which case it is better to unmap the
1459                          * page.
1460                          */
1461                         pgprintk("misaligned: gpa %llx bytes %d role %x\n",
1462                                  gpa, bytes, sp->role.word);
1463                         kvm_mmu_zap_page(vcpu->kvm, sp);
1464                         ++vcpu->kvm->stat.mmu_flooded;
1465                         continue;
1466                 }
1467                 page_offset = offset;
1468                 level = sp->role.level;
1469                 npte = 1;
1470                 if (sp->role.glevels == PT32_ROOT_LEVEL) {
1471                         page_offset <<= 1;      /* 32->64 */
1472                         /*
1473                          * A 32-bit pde maps 4MB while the shadow pdes map
1474                          * only 2MB.  So we need to double the offset again
1475                          * and zap two pdes instead of one.
1476                          */
1477                         if (level == PT32_ROOT_LEVEL) {
1478                                 page_offset &= ~7; /* kill rounding error */
1479                                 page_offset <<= 1;
1480                                 npte = 2;
1481                         }
1482                         quadrant = page_offset >> PAGE_SHIFT;
1483                         page_offset &= ~PAGE_MASK;
1484                         if (quadrant != sp->role.quadrant)
1485                                 continue;
1486                 }
1487                 spte = &sp->spt[page_offset / sizeof(*spte)];
1488                 while (npte--) {
1489                         entry = *spte;
1490                         mmu_pte_write_zap_pte(vcpu, sp, spte);
1491                         mmu_pte_write_new_pte(vcpu, sp, spte, new, bytes,
1492                                               page_offset & (pte_size - 1));
1493                         mmu_pte_write_flush_tlb(vcpu, entry, *spte);
1494                         ++spte;
1495                 }
1496         }
1497         kvm_mmu_audit(vcpu, "post pte write");
1498         spin_unlock(&vcpu->kvm->mmu_lock);
1499         if (vcpu->arch.update_pte.page) {
1500                 kvm_release_page_clean(vcpu->arch.update_pte.page);
1501                 vcpu->arch.update_pte.page = NULL;
1502         }
1503 }
1504
1505 int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
1506 {
1507         gpa_t gpa;
1508         int r;
1509
1510         down_read(&vcpu->kvm->slots_lock);
1511         gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva);
1512         up_read(&vcpu->kvm->slots_lock);
1513
1514         spin_lock(&vcpu->kvm->mmu_lock);
1515         r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
1516         spin_unlock(&vcpu->kvm->mmu_lock);
1517         return r;
1518 }
1519
1520 void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
1521 {
1522         while (vcpu->kvm->arch.n_free_mmu_pages < KVM_REFILL_PAGES) {
1523                 struct kvm_mmu_page *sp;
1524
1525                 sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev,
1526                                   struct kvm_mmu_page, link);
1527                 kvm_mmu_zap_page(vcpu->kvm, sp);
1528                 ++vcpu->kvm->stat.mmu_recycled;
1529         }
1530 }
1531
1532 int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code)
1533 {
1534         int r;
1535         enum emulation_result er;
1536
1537         r = vcpu->arch.mmu.page_fault(vcpu, cr2, error_code);
1538         if (r < 0)
1539                 goto out;
1540
1541         if (!r) {
1542                 r = 1;
1543                 goto out;
1544         }
1545
1546         r = mmu_topup_memory_caches(vcpu);
1547         if (r)
1548                 goto out;
1549
1550         er = emulate_instruction(vcpu, vcpu->run, cr2, error_code, 0);
1551
1552         switch (er) {
1553         case EMULATE_DONE:
1554                 return 1;
1555         case EMULATE_DO_MMIO:
1556                 ++vcpu->stat.mmio_exits;
1557                 return 0;
1558         case EMULATE_FAIL:
1559                 kvm_report_emulation_failure(vcpu, "pagetable");
1560                 return 1;
1561         default:
1562                 BUG();
1563         }
1564 out:
1565         return r;
1566 }
1567 EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);
1568
1569 static void free_mmu_pages(struct kvm_vcpu *vcpu)
1570 {
1571         struct kvm_mmu_page *sp;
1572
1573         while (!list_empty(&vcpu->kvm->arch.active_mmu_pages)) {
1574                 sp = container_of(vcpu->kvm->arch.active_mmu_pages.next,
1575                                   struct kvm_mmu_page, link);
1576                 kvm_mmu_zap_page(vcpu->kvm, sp);
1577         }
1578         free_page((unsigned long)vcpu->arch.mmu.pae_root);
1579 }
1580
1581 static int alloc_mmu_pages(struct kvm_vcpu *vcpu)
1582 {
1583         struct page *page;
1584         int i;
1585
1586         ASSERT(vcpu);
1587
1588         if (vcpu->kvm->arch.n_requested_mmu_pages)
1589                 vcpu->kvm->arch.n_free_mmu_pages =
1590                                         vcpu->kvm->arch.n_requested_mmu_pages;
1591         else
1592                 vcpu->kvm->arch.n_free_mmu_pages =
1593                                         vcpu->kvm->arch.n_alloc_mmu_pages;
1594         /*
1595          * When emulating 32-bit mode, cr3 is only 32 bits even on x86_64.
1596          * Therefore we need to allocate shadow page tables in the first
1597          * 4GB of memory, which happens to fit the DMA32 zone.
1598          */
1599         page = alloc_page(GFP_KERNEL | __GFP_DMA32);
1600         if (!page)
1601                 goto error_1;
1602         vcpu->arch.mmu.pae_root = page_address(page);
1603         for (i = 0; i < 4; ++i)
1604                 vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
1605
1606         return 0;
1607
1608 error_1:
1609         free_mmu_pages(vcpu);
1610         return -ENOMEM;
1611 }
1612
1613 int kvm_mmu_create(struct kvm_vcpu *vcpu)
1614 {
1615         ASSERT(vcpu);
1616         ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
1617
1618         return alloc_mmu_pages(vcpu);
1619 }
1620
1621 int kvm_mmu_setup(struct kvm_vcpu *vcpu)
1622 {
1623         ASSERT(vcpu);
1624         ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
1625
1626         return init_kvm_mmu(vcpu);
1627 }
1628
1629 void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
1630 {
1631         ASSERT(vcpu);
1632
1633         destroy_kvm_mmu(vcpu);
1634         free_mmu_pages(vcpu);
1635         mmu_free_memory_caches(vcpu);
1636 }
1637
1638 void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
1639 {
1640         struct kvm_mmu_page *sp;
1641
1642         list_for_each_entry(sp, &kvm->arch.active_mmu_pages, link) {
1643                 int i;
1644                 u64 *pt;
1645
1646                 if (!test_bit(slot, &sp->slot_bitmap))
1647                         continue;
1648
1649                 pt = sp->spt;
1650                 for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
1651                         /* avoid RMW */
1652                         if (pt[i] & PT_WRITABLE_MASK)
1653                                 pt[i] &= ~PT_WRITABLE_MASK;
1654         }
1655 }
1656
1657 void kvm_mmu_zap_all(struct kvm *kvm)
1658 {
1659         struct kvm_mmu_page *sp, *node;
1660
1661         spin_lock(&kvm->mmu_lock);
1662         list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link)
1663                 kvm_mmu_zap_page(kvm, sp);
1664         spin_unlock(&kvm->mmu_lock);
1665
1666         kvm_flush_remote_tlbs(kvm);
1667 }
1668
1669 void kvm_mmu_module_exit(void)
1670 {
1671         if (pte_chain_cache)
1672                 kmem_cache_destroy(pte_chain_cache);
1673         if (rmap_desc_cache)
1674                 kmem_cache_destroy(rmap_desc_cache);
1675         if (mmu_page_header_cache)
1676                 kmem_cache_destroy(mmu_page_header_cache);
1677 }
1678
1679 int kvm_mmu_module_init(void)
1680 {
1681         pte_chain_cache = kmem_cache_create("kvm_pte_chain",
1682                                             sizeof(struct kvm_pte_chain),
1683                                             0, 0, NULL);
1684         if (!pte_chain_cache)
1685                 goto nomem;
1686         rmap_desc_cache = kmem_cache_create("kvm_rmap_desc",
1687                                             sizeof(struct kvm_rmap_desc),
1688                                             0, 0, NULL);
1689         if (!rmap_desc_cache)
1690                 goto nomem;
1691
1692         mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
1693                                                   sizeof(struct kvm_mmu_page),
1694                                                   0, 0, NULL);
1695         if (!mmu_page_header_cache)
1696                 goto nomem;
1697
1698         return 0;
1699
1700 nomem:
1701         kvm_mmu_module_exit();
1702         return -ENOMEM;
1703 }
1704
1705 /*
1706  * Caculate mmu pages needed for kvm.
1707  */
1708 unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
1709 {
1710         int i;
1711         unsigned int nr_mmu_pages;
1712         unsigned int  nr_pages = 0;
1713
1714         for (i = 0; i < kvm->nmemslots; i++)
1715                 nr_pages += kvm->memslots[i].npages;
1716
1717         nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000;
1718         nr_mmu_pages = max(nr_mmu_pages,
1719                         (unsigned int) KVM_MIN_ALLOC_MMU_PAGES);
1720
1721         return nr_mmu_pages;
1722 }
1723
1724 #ifdef AUDIT
1725
1726 static const char *audit_msg;
1727
1728 static gva_t canonicalize(gva_t gva)
1729 {
1730 #ifdef CONFIG_X86_64
1731         gva = (long long)(gva << 16) >> 16;
1732 #endif
1733         return gva;
1734 }
1735
1736 static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
1737                                 gva_t va, int level)
1738 {
1739         u64 *pt = __va(page_pte & PT64_BASE_ADDR_MASK);
1740         int i;
1741         gva_t va_delta = 1ul << (PAGE_SHIFT + 9 * (level - 1));
1742
1743         for (i = 0; i < PT64_ENT_PER_PAGE; ++i, va += va_delta) {
1744                 u64 ent = pt[i];
1745
1746                 if (ent == shadow_trap_nonpresent_pte)
1747                         continue;
1748
1749                 va = canonicalize(va);
1750                 if (level > 1) {
1751                         if (ent == shadow_notrap_nonpresent_pte)
1752                                 printk(KERN_ERR "audit: (%s) nontrapping pte"
1753                                        " in nonleaf level: levels %d gva %lx"
1754                                        " level %d pte %llx\n", audit_msg,
1755                                        vcpu->arch.mmu.root_level, va, level, ent);
1756
1757                         audit_mappings_page(vcpu, ent, va, level - 1);
1758                 } else {
1759                         gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, va);
1760                         struct page *page = gpa_to_page(vcpu, gpa);
1761                         hpa_t hpa = page_to_phys(page);
1762
1763                         if (is_shadow_present_pte(ent)
1764                             && (ent & PT64_BASE_ADDR_MASK) != hpa)
1765                                 printk(KERN_ERR "xx audit error: (%s) levels %d"
1766                                        " gva %lx gpa %llx hpa %llx ent %llx %d\n",
1767                                        audit_msg, vcpu->arch.mmu.root_level,
1768                                        va, gpa, hpa, ent,
1769                                        is_shadow_present_pte(ent));
1770                         else if (ent == shadow_notrap_nonpresent_pte
1771                                  && !is_error_hpa(hpa))
1772                                 printk(KERN_ERR "audit: (%s) notrap shadow,"
1773                                        " valid guest gva %lx\n", audit_msg, va);
1774                         kvm_release_page_clean(page);
1775
1776                 }
1777         }
1778 }
1779
1780 static void audit_mappings(struct kvm_vcpu *vcpu)
1781 {
1782         unsigned i;
1783
1784         if (vcpu->arch.mmu.root_level == 4)
1785                 audit_mappings_page(vcpu, vcpu->arch.mmu.root_hpa, 0, 4);
1786         else
1787                 for (i = 0; i < 4; ++i)
1788                         if (vcpu->arch.mmu.pae_root[i] & PT_PRESENT_MASK)
1789                                 audit_mappings_page(vcpu,
1790                                                     vcpu->arch.mmu.pae_root[i],
1791                                                     i << 30,
1792                                                     2);
1793 }
1794
1795 static int count_rmaps(struct kvm_vcpu *vcpu)
1796 {
1797         int nmaps = 0;
1798         int i, j, k;
1799
1800         for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
1801                 struct kvm_memory_slot *m = &vcpu->kvm->memslots[i];
1802                 struct kvm_rmap_desc *d;
1803
1804                 for (j = 0; j < m->npages; ++j) {
1805                         unsigned long *rmapp = &m->rmap[j];
1806
1807                         if (!*rmapp)
1808                                 continue;
1809                         if (!(*rmapp & 1)) {
1810                                 ++nmaps;
1811                                 continue;
1812                         }
1813                         d = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
1814                         while (d) {
1815                                 for (k = 0; k < RMAP_EXT; ++k)
1816                                         if (d->shadow_ptes[k])
1817                                                 ++nmaps;
1818                                         else
1819                                                 break;
1820                                 d = d->more;
1821                         }
1822                 }
1823         }
1824         return nmaps;
1825 }
1826
1827 static int count_writable_mappings(struct kvm_vcpu *vcpu)
1828 {
1829         int nmaps = 0;
1830         struct kvm_mmu_page *sp;
1831         int i;
1832
1833         list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
1834                 u64 *pt = sp->spt;
1835
1836                 if (sp->role.level != PT_PAGE_TABLE_LEVEL)
1837                         continue;
1838
1839                 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
1840                         u64 ent = pt[i];
1841
1842                         if (!(ent & PT_PRESENT_MASK))
1843                                 continue;
1844                         if (!(ent & PT_WRITABLE_MASK))
1845                                 continue;
1846                         ++nmaps;
1847                 }
1848         }
1849         return nmaps;
1850 }
1851
1852 static void audit_rmap(struct kvm_vcpu *vcpu)
1853 {
1854         int n_rmap = count_rmaps(vcpu);
1855         int n_actual = count_writable_mappings(vcpu);
1856
1857         if (n_rmap != n_actual)
1858                 printk(KERN_ERR "%s: (%s) rmap %d actual %d\n",
1859                        __FUNCTION__, audit_msg, n_rmap, n_actual);
1860 }
1861
1862 static void audit_write_protection(struct kvm_vcpu *vcpu)
1863 {
1864         struct kvm_mmu_page *sp;
1865         struct kvm_memory_slot *slot;
1866         unsigned long *rmapp;
1867         gfn_t gfn;
1868
1869         list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
1870                 if (sp->role.metaphysical)
1871                         continue;
1872
1873                 slot = gfn_to_memslot(vcpu->kvm, sp->gfn);
1874                 gfn = unalias_gfn(vcpu->kvm, sp->gfn);
1875                 rmapp = &slot->rmap[gfn - slot->base_gfn];
1876                 if (*rmapp)
1877                         printk(KERN_ERR "%s: (%s) shadow page has writable"
1878                                " mappings: gfn %lx role %x\n",
1879                                __FUNCTION__, audit_msg, sp->gfn,
1880                                sp->role.word);
1881         }
1882 }
1883
1884 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg)
1885 {
1886         int olddbg = dbg;
1887
1888         dbg = 0;
1889         audit_msg = msg;
1890         audit_rmap(vcpu);
1891         audit_write_protection(vcpu);
1892         audit_mappings(vcpu);
1893         dbg = olddbg;
1894 }
1895
1896 #endif