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   1 /*
   2  * Kernel-based Virtual Machine driver for Linux
   3  *
   4  * This module enables machines with Intel VT-x extensions to run virtual
   5  * machines without emulation or binary translation.
   6  *
   7  * MMU support
   8  *
   9  * Copyright (C) 2006 Qumranet, Inc.
  10  *
  11  * Authors:
  12  *   Yaniv Kamay  <yaniv@qumranet.com>
  13  *   Avi Kivity   <avi@qumranet.com>
  14  *
  15  * This work is licensed under the terms of the GNU GPL, version 2.  See
  16  * the COPYING file in the top-level directory.
  17  *
  18  */
  19
  20 #include "mmu.h"
  21
  22 #include <linux/kvm_host.h>
  23 #include <linux/types.h>
  24 #include <linux/string.h>
  25 #include <linux/mm.h>
  26 #include <linux/highmem.h>
  27 #include <linux/module.h>
  28 #include <linux/swap.h>
  29 #include <linux/hugetlb.h>
  30 #include <linux/compiler.h>
  31
  32 #include <asm/page.h>
  33 #include <asm/cmpxchg.h>
  34 #include <asm/io.h>
  35 #include <asm/vmx.h>
  36
  37 /*
  38  * When setting this variable to true it enables Two-Dimensional-Paging
  39  * where the hardware walks 2 page tables:
  40  * 1. the guest-virtual to guest-physical
  41  * 2. while doing 1. it walks guest-physical to host-physical
  42  * If the hardware supports that we don't need to do shadow paging.
  43  */
  44 bool tdp_enabled = false;
  45
  46 #undef MMU_DEBUG
  47
  48 #undef AUDIT
  49
  50 #ifdef AUDIT
  51 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg);
  52 #else
  53 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg) {}
  54 #endif
  55
  56 #ifdef MMU_DEBUG
  57
  58 #define pgprintk(x...) do { if (dbg) printk(x); } while (0)
  59 #define rmap_printk(x...) do { if (dbg) printk(x); } while (0)
  60
  61 #else
  62
  63 #define pgprintk(x...) do { } while (0)
  64 #define rmap_printk(x...) do { } while (0)
  65
  66 #endif
  67
  68 #if defined(MMU_DEBUG) || defined(AUDIT)
  69 static int dbg = 0;
  70 module_param(dbg, bool, 0644);
  71 #endif
  72
  73 static int oos_shadow = 1;
  74 module_param(oos_shadow, bool, 0644);
  75
  76 #ifndef MMU_DEBUG
  77 #define ASSERT(x) do { } while (0)
  78 #else
  79 #define ASSERT(x)                                                       \
  80         if (!(x)) {                                                     \
  81                 printk(KERN_WARNING "assertion failed %s:%d: %s\n",     \
  82                        __FILE__, __LINE__, #x);                         \
  83         }
  84 #endif
  85
  86 #define PT_FIRST_AVAIL_BITS_SHIFT 9
  87 #define PT64_SECOND_AVAIL_BITS_SHIFT 52
  88
  89 #define VALID_PAGE(x) ((x) != INVALID_PAGE)
  90
  91 #define PT64_LEVEL_BITS 9
  92
  93 #define PT64_LEVEL_SHIFT(level) \
  94                 (PAGE_SHIFT + (level - 1) * PT64_LEVEL_BITS)
  95
  96 #define PT64_LEVEL_MASK(level) \
  97                 (((1ULL << PT64_LEVEL_BITS) - 1) << PT64_LEVEL_SHIFT(level))
  98
  99 #define PT64_INDEX(address, level)\
 100         (((address) >> PT64_LEVEL_SHIFT(level)) & ((1 << PT64_LEVEL_BITS) - 1))
 101
 102
 103 #define PT32_LEVEL_BITS 10
 104
 105 #define PT32_LEVEL_SHIFT(level) \
 106                 (PAGE_SHIFT + (level - 1) * PT32_LEVEL_BITS)
 107
 108 #define PT32_LEVEL_MASK(level) \
 109                 (((1ULL << PT32_LEVEL_BITS) - 1) << PT32_LEVEL_SHIFT(level))
 110
 111 #define PT32_INDEX(address, level)\
 112         (((address) >> PT32_LEVEL_SHIFT(level)) & ((1 << PT32_LEVEL_BITS) - 1))
 113
 114
 115 #define PT64_BASE_ADDR_MASK (((1ULL << 52) - 1) & ~(u64)(PAGE_SIZE-1))
 116 #define PT64_DIR_BASE_ADDR_MASK \
 117         (PT64_BASE_ADDR_MASK & ~((1ULL << (PAGE_SHIFT + PT64_LEVEL_BITS)) - 1))
 118
 119 #define PT32_BASE_ADDR_MASK PAGE_MASK
 120 #define PT32_DIR_BASE_ADDR_MASK \
 121         (PAGE_MASK & ~((1ULL << (PAGE_SHIFT + PT32_LEVEL_BITS)) - 1))
 122
 123 #define PT64_PERM_MASK (PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK \
 124                         | PT64_NX_MASK)
 125
 126 #define PFERR_PRESENT_MASK (1U << 0)
 127 #define PFERR_WRITE_MASK (1U << 1)
 128 #define PFERR_USER_MASK (1U << 2)
 129 #define PFERR_FETCH_MASK (1U << 4)
 130
 131 #define PT_DIRECTORY_LEVEL 2
 132 #define PT_PAGE_TABLE_LEVEL 1
 133
 134 #define RMAP_EXT 4
 135
 136 #define ACC_EXEC_MASK    1
 137 #define ACC_WRITE_MASK   PT_WRITABLE_MASK
 138 #define ACC_USER_MASK    PT_USER_MASK
 139 #define ACC_ALL          (ACC_EXEC_MASK | ACC_WRITE_MASK | ACC_USER_MASK)
 140
 141 #define SHADOW_PT_INDEX(addr, level) PT64_INDEX(addr, level)
 142
 143 struct kvm_rmap_desc {
 144         u64 *shadow_ptes[RMAP_EXT];
 145         struct kvm_rmap_desc *more;
 146 };
 147
 148 struct kvm_shadow_walk {
 149         int (*entry)(struct kvm_shadow_walk *walk, struct kvm_vcpu *vcpu,
 150                      u64 addr, u64 *spte, int level);
 151 };
 152
 153 struct kvm_unsync_walk {
 154         int (*entry) (struct kvm_mmu_page *sp, struct kvm_unsync_walk *walk);
 155 };
 156
 157 typedef int (*mmu_parent_walk_fn) (struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp);
 158
 159 static struct kmem_cache *pte_chain_cache;
 160 static struct kmem_cache *rmap_desc_cache;
 161 static struct kmem_cache *mmu_page_header_cache;
 162
 163 static u64 __read_mostly shadow_trap_nonpresent_pte;
 164 static u64 __read_mostly shadow_notrap_nonpresent_pte;
 165 static u64 __read_mostly shadow_base_present_pte;
 166 static u64 __read_mostly shadow_nx_mask;
 167 static u64 __read_mostly shadow_x_mask; /* mutual exclusive with nx_mask */
 168 static u64 __read_mostly shadow_user_mask;
 169 static u64 __read_mostly shadow_accessed_mask;
 170 static u64 __read_mostly shadow_dirty_mask;
 171 static u64 __read_mostly shadow_mt_mask;
 172
 173 void kvm_mmu_set_nonpresent_ptes(u64 trap_pte, u64 notrap_pte)
 174 {
 175         shadow_trap_nonpresent_pte = trap_pte;
 176         shadow_notrap_nonpresent_pte = notrap_pte;
 177 }
 178 EXPORT_SYMBOL_GPL(kvm_mmu_set_nonpresent_ptes);
 179
 180 void kvm_mmu_set_base_ptes(u64 base_pte)
 181 {
 182         shadow_base_present_pte = base_pte;
 183 }
 184 EXPORT_SYMBOL_GPL(kvm_mmu_set_base_ptes);
 185
 186 void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
 187                 u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 mt_mask)
 188 {
 189         shadow_user_mask = user_mask;
 190         shadow_accessed_mask = accessed_mask;
 191         shadow_dirty_mask = dirty_mask;
 192         shadow_nx_mask = nx_mask;
 193         shadow_x_mask = x_mask;
 194         shadow_mt_mask = mt_mask;
 195 }
 196 EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);
 197
 198 static int is_write_protection(struct kvm_vcpu *vcpu)
 199 {
 200         return vcpu->arch.cr0 & X86_CR0_WP;
 201 }
 202
 203 static int is_cpuid_PSE36(void)
 204 {
 205         return 1;
 206 }
 207
 208 static int is_nx(struct kvm_vcpu *vcpu)
 209 {
 210         return vcpu->arch.shadow_efer & EFER_NX;
 211 }
 212
 213 static int is_present_pte(unsigned long pte)
 214 {
 215         return pte & PT_PRESENT_MASK;
 216 }
 217
 218 static int is_shadow_present_pte(u64 pte)
 219 {
 220         return pte != shadow_trap_nonpresent_pte
 221                 && pte != shadow_notrap_nonpresent_pte;
 222 }
 223
 224 static int is_large_pte(u64 pte)
 225 {
 226         return pte & PT_PAGE_SIZE_MASK;
 227 }
 228
 229 static int is_writeble_pte(unsigned long pte)
 230 {
 231         return pte & PT_WRITABLE_MASK;
 232 }
 233
 234 static int is_dirty_pte(unsigned long pte)
 235 {
 236         return pte & shadow_dirty_mask;
 237 }
 238
 239 static int is_rmap_pte(u64 pte)
 240 {
 241         return is_shadow_present_pte(pte);
 242 }
 243
 244 static pfn_t spte_to_pfn(u64 pte)
 245 {
 246         return (pte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
 247 }
 248
 249 static gfn_t pse36_gfn_delta(u32 gpte)
 250 {
 251         int shift = 32 - PT32_DIR_PSE36_SHIFT - PAGE_SHIFT;
 252
 253         return (gpte & PT32_DIR_PSE36_MASK) << shift;
 254 }
 255
 256 static void set_shadow_pte(u64 *sptep, u64 spte)
 257 {
 258 #ifdef CONFIG_X86_64
 259         set_64bit((unsigned long *)sptep, spte);
 260 #else
 261         set_64bit((unsigned long long *)sptep, spte);
 262 #endif
 263 }
 264
 265 static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
 266                                   struct kmem_cache *base_cache, int min)
 267 {
 268         void *obj;
 269
 270         if (cache->nobjs >= min)
 271                 return 0;
 272         while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
 273                 obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
 274                 if (!obj)
 275                         return -ENOMEM;
 276                 cache->objects[cache->nobjs++] = obj;
 277         }
 278         return 0;
 279 }
 280
 281 static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
 282 {
 283         while (mc->nobjs)
 284                 kfree(mc->objects[--mc->nobjs]);
 285 }
 286
 287 static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
 288                                        int min)
 289 {
 290         struct page *page;
 291
 292         if (cache->nobjs >= min)
 293                 return 0;
 294         while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
 295                 page = alloc_page(GFP_KERNEL);
 296                 if (!page)
 297                         return -ENOMEM;
 298                 set_page_private(page, 0);
 299                 cache->objects[cache->nobjs++] = page_address(page);
 300         }
 301         return 0;
 302 }
 303
 304 static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
 305 {
 306         while (mc->nobjs)
 307                 free_page((unsigned long)mc->objects[--mc->nobjs]);
 308 }
 309
 310 static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
 311 {
 312         int r;
 313
 314         r = mmu_topup_memory_cache(&vcpu->arch.mmu_pte_chain_cache,
 315                                    pte_chain_cache, 4);
 316         if (r)
 317                 goto out;
 318         r = mmu_topup_memory_cache(&vcpu->arch.mmu_rmap_desc_cache,
 319                                    rmap_desc_cache, 4);
 320         if (r)
 321                 goto out;
 322         r = mmu_topup_memory_cache_page(&vcpu->arch.mmu_page_cache, 8);
 323         if (r)
 324                 goto out;
 325         r = mmu_topup_memory_cache(&vcpu->arch.mmu_page_header_cache,
 326                                    mmu_page_header_cache, 4);
 327 out:
 328         return r;
 329 }
 330
 331 static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
 332 {
 333         mmu_free_memory_cache(&vcpu->arch.mmu_pte_chain_cache);
 334         mmu_free_memory_cache(&vcpu->arch.mmu_rmap_desc_cache);
 335         mmu_free_memory_cache_page(&vcpu->arch.mmu_page_cache);
 336         mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache);
 337 }
 338
 339 static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc,
 340                                     size_t size)
 341 {
 342         void *p;
 343
 344         BUG_ON(!mc->nobjs);
 345         p = mc->objects[--mc->nobjs];
 346         memset(p, 0, size);
 347         return p;
 348 }
 349
 350 static struct kvm_pte_chain *mmu_alloc_pte_chain(struct kvm_vcpu *vcpu)
 351 {
 352         return mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_chain_cache,
 353                                       sizeof(struct kvm_pte_chain));
 354 }
 355
 356 static void mmu_free_pte_chain(struct kvm_pte_chain *pc)
 357 {
 358         kfree(pc);
 359 }
 360
 361 static struct kvm_rmap_desc *mmu_alloc_rmap_desc(struct kvm_vcpu *vcpu)
 362 {
 363         return mmu_memory_cache_alloc(&vcpu->arch.mmu_rmap_desc_cache,
 364                                       sizeof(struct kvm_rmap_desc));
 365 }
 366
 367 static void mmu_free_rmap_desc(struct kvm_rmap_desc *rd)
 368 {
 369         kfree(rd);
 370 }
 371
 372 /*
 373  * Return the pointer to the largepage write count for a given
 374  * gfn, handling slots that are not large page aligned.
 375  */
 376 static int *slot_largepage_idx(gfn_t gfn, struct kvm_memory_slot *slot)
 377 {
 378         unsigned long idx;
 379
 380         idx = (gfn / KVM_PAGES_PER_HPAGE) -
 381               (slot->base_gfn / KVM_PAGES_PER_HPAGE);
 382         return &slot->lpage_info[idx].write_count;
 383 }
 384
 385 static void account_shadowed(struct kvm *kvm, gfn_t gfn)
 386 {
 387         int *write_count;
 388
 389         gfn = unalias_gfn(kvm, gfn);
 390         write_count = slot_largepage_idx(gfn,
 391                                          gfn_to_memslot_unaliased(kvm, gfn));
 392         *write_count += 1;
 393 }
 394
 395 static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn)
 396 {
 397         int *write_count;
 398
 399         gfn = unalias_gfn(kvm, gfn);
 400         write_count = slot_largepage_idx(gfn,
 401                                          gfn_to_memslot_unaliased(kvm, gfn));
 402         *write_count -= 1;
 403         WARN_ON(*write_count < 0);
 404 }
 405
 406 static int has_wrprotected_page(struct kvm *kvm, gfn_t gfn)
 407 {
 408         struct kvm_memory_slot *slot;
 409         int *largepage_idx;
 410
 411         gfn = unalias_gfn(kvm, gfn);
 412         slot = gfn_to_memslot_unaliased(kvm, gfn);
 413         if (slot) {
 414                 largepage_idx = slot_largepage_idx(gfn, slot);
 415                 return *largepage_idx;
 416         }
 417
 418         return 1;
 419 }
 420
 421 static int host_largepage_backed(struct kvm *kvm, gfn_t gfn)
 422 {
 423         struct vm_area_struct *vma;
 424         unsigned long addr;
 425         int ret = 0;
 426
 427         addr = gfn_to_hva(kvm, gfn);
 428         if (kvm_is_error_hva(addr))
 429                 return ret;
 430
 431         down_read(&current->mm->mmap_sem);
 432         vma = find_vma(current->mm, addr);
 433         if (vma && is_vm_hugetlb_page(vma))
 434                 ret = 1;
 435         up_read(&current->mm->mmap_sem);
 436
 437         return ret;
 438 }
 439
 440 static int is_largepage_backed(struct kvm_vcpu *vcpu, gfn_t large_gfn)
 441 {
 442         struct kvm_memory_slot *slot;
 443
 444         if (has_wrprotected_page(vcpu->kvm, large_gfn))
 445                 return 0;
 446
 447         if (!host_largepage_backed(vcpu->kvm, large_gfn))
 448                 return 0;
 449
 450         slot = gfn_to_memslot(vcpu->kvm, large_gfn);
 451         if (slot && slot->dirty_bitmap)
 452                 return 0;
 453
 454         return 1;
 455 }
 456
 457 /*
 458  * Take gfn and return the reverse mapping to it.
 459  * Note: gfn must be unaliased before this function get called
 460  */
 461
 462 static unsigned long *gfn_to_rmap(struct kvm *kvm, gfn_t gfn, int lpage)
 463 {
 464         struct kvm_memory_slot *slot;
 465         unsigned long idx;
 466
 467         slot = gfn_to_memslot(kvm, gfn);
 468         if (!lpage)
 469                 return &slot->rmap[gfn - slot->base_gfn];
 470
 471         idx = (gfn / KVM_PAGES_PER_HPAGE) -
 472               (slot->base_gfn / KVM_PAGES_PER_HPAGE);
 473
 474         return &slot->lpage_info[idx].rmap_pde;
 475 }
 476
 477 /*
 478  * Reverse mapping data structures:
 479  *
 480  * If rmapp bit zero is zero, then rmapp point to the shadw page table entry
 481  * that points to page_address(page).
 482  *
 483  * If rmapp bit zero is one, (then rmap & ~1) points to a struct kvm_rmap_desc
 484  * containing more mappings.
 485  */
 486 static void rmap_add(struct kvm_vcpu *vcpu, u64 *spte, gfn_t gfn, int lpage)
 487 {
 488         struct kvm_mmu_page *sp;
 489         struct kvm_rmap_desc *desc;
 490         unsigned long *rmapp;
 491         int i;
 492
 493         if (!is_rmap_pte(*spte))
 494                 return;
 495         gfn = unalias_gfn(vcpu->kvm, gfn);
 496         sp = page_header(__pa(spte));
 497         sp->gfns[spte - sp->spt] = gfn;
 498         rmapp = gfn_to_rmap(vcpu->kvm, gfn, lpage);
 499         if (!*rmapp) {
 500                 rmap_printk("rmap_add: %p %llx 0->1\n", spte, *spte);
 501                 *rmapp = (unsigned long)spte;
 502         } else if (!(*rmapp & 1)) {
 503                 rmap_printk("rmap_add: %p %llx 1->many\n", spte, *spte);
 504                 desc = mmu_alloc_rmap_desc(vcpu);
 505                 desc->shadow_ptes[0] = (u64 *)*rmapp;
 506                 desc->shadow_ptes[1] = spte;
 507                 *rmapp = (unsigned long)desc | 1;
 508         } else {
 509                 rmap_printk("rmap_add: %p %llx many->many\n", spte, *spte);
 510                 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
 511                 while (desc->shadow_ptes[RMAP_EXT-1] && desc->more)
 512                         desc = desc->more;
 513                 if (desc->shadow_ptes[RMAP_EXT-1]) {
 514                         desc->more = mmu_alloc_rmap_desc(vcpu);
 515                         desc = desc->more;
 516                 }
 517                 for (i = 0; desc->shadow_ptes[i]; ++i)
 518                         ;
 519                 desc->shadow_ptes[i] = spte;
 520         }
 521 }
 522
 523 static void rmap_desc_remove_entry(unsigned long *rmapp,
 524                                    struct kvm_rmap_desc *desc,
 525                                    int i,
 526                                    struct kvm_rmap_desc *prev_desc)
 527 {
 528         int j;
 529
 530         for (j = RMAP_EXT - 1; !desc->shadow_ptes[j] && j > i; --j)
 531                 ;
 532         desc->shadow_ptes[i] = desc->shadow_ptes[j];
 533         desc->shadow_ptes[j] = NULL;
 534         if (j != 0)
 535                 return;
 536         if (!prev_desc && !desc->more)
 537                 *rmapp = (unsigned long)desc->shadow_ptes[0];
 538         else
 539                 if (prev_desc)
 540                         prev_desc->more = desc->more;
 541                 else
 542                         *rmapp = (unsigned long)desc->more | 1;
 543         mmu_free_rmap_desc(desc);
 544 }
 545
 546 static void rmap_remove(struct kvm *kvm, u64 *spte)
 547 {
 548         struct kvm_rmap_desc *desc;
 549         struct kvm_rmap_desc *prev_desc;
 550         struct kvm_mmu_page *sp;
 551         pfn_t pfn;
 552         unsigned long *rmapp;
 553         int i;
 554
 555         if (!is_rmap_pte(*spte))
 556                 return;
 557         sp = page_header(__pa(spte));
 558         pfn = spte_to_pfn(*spte);
 559         if (*spte & shadow_accessed_mask)
 560                 kvm_set_pfn_accessed(pfn);
 561         if (is_writeble_pte(*spte))
 562                 kvm_release_pfn_dirty(pfn);
 563         else
 564                 kvm_release_pfn_clean(pfn);
 565         rmapp = gfn_to_rmap(kvm, sp->gfns[spte - sp->spt], is_large_pte(*spte));
 566         if (!*rmapp) {
 567                 printk(KERN_ERR "rmap_remove: %p %llx 0->BUG\n", spte, *spte);
 568                 BUG();
 569         } else if (!(*rmapp & 1)) {
 570                 rmap_printk("rmap_remove:  %p %llx 1->0\n", spte, *spte);
 571                 if ((u64 *)*rmapp != spte) {
 572                         printk(KERN_ERR "rmap_remove:  %p %llx 1->BUG\n",
 573                                spte, *spte);
 574                         BUG();
 575                 }
 576                 *rmapp = 0;
 577         } else {
 578                 rmap_printk("rmap_remove:  %p %llx many->many\n", spte, *spte);
 579                 desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
 580                 prev_desc = NULL;
 581                 while (desc) {
 582                         for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i)
 583                                 if (desc->shadow_ptes[i] == spte) {
 584                                         rmap_desc_remove_entry(rmapp,
 585                                                                desc, i,
 586                                                                prev_desc);
 587                                         return;
 588                                 }
 589                         prev_desc = desc;
 590                         desc = desc->more;
 591                 }
 592                 BUG();
 593         }
 594 }
 595
 596 static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte)
 597 {
 598         struct kvm_rmap_desc *desc;
 599         struct kvm_rmap_desc *prev_desc;
 600         u64 *prev_spte;
 601         int i;
 602
 603         if (!*rmapp)
 604                 return NULL;
 605         else if (!(*rmapp & 1)) {
 606                 if (!spte)
 607                         return (u64 *)*rmapp;
 608                 return NULL;
 609         }
 610         desc = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
 611         prev_desc = NULL;
 612         prev_spte = NULL;
 613         while (desc) {
 614                 for (i = 0; i < RMAP_EXT && desc->shadow_ptes[i]; ++i) {
 615                         if (prev_spte == spte)
 616                                 return desc->shadow_ptes[i];
 617                         prev_spte = desc->shadow_ptes[i];
 618                 }
 619                 desc = desc->more;
 620         }
 621         return NULL;
 622 }
 623
 624 static void rmap_write_protect(struct kvm *kvm, u64 gfn)
 625 {
 626         unsigned long *rmapp;
 627         u64 *spte;
 628         int write_protected = 0;
 629
 630         gfn = unalias_gfn(kvm, gfn);
 631         rmapp = gfn_to_rmap(kvm, gfn, 0);
 632
 633         spte = rmap_next(kvm, rmapp, NULL);
 634         while (spte) {
 635                 BUG_ON(!spte);
 636                 BUG_ON(!(*spte & PT_PRESENT_MASK));
 637                 rmap_printk("rmap_write_protect: spte %p %llx\n", spte, *spte);
 638                 if (is_writeble_pte(*spte)) {
 639                         set_shadow_pte(spte, *spte & ~PT_WRITABLE_MASK);
 640                         write_protected = 1;
 641                 }
 642                 spte = rmap_next(kvm, rmapp, spte);
 643         }
 644         if (write_protected) {
 645                 pfn_t pfn;
 646
 647                 spte = rmap_next(kvm, rmapp, NULL);
 648                 pfn = spte_to_pfn(*spte);
 649                 kvm_set_pfn_dirty(pfn);
 650         }
 651
 652         /* check for huge page mappings */
 653         rmapp = gfn_to_rmap(kvm, gfn, 1);
 654         spte = rmap_next(kvm, rmapp, NULL);
 655         while (spte) {
 656                 BUG_ON(!spte);
 657                 BUG_ON(!(*spte & PT_PRESENT_MASK));
 658                 BUG_ON((*spte & (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK)) != (PT_PAGE_SIZE_MASK|PT_PRESENT_MASK));
 659                 pgprintk("rmap_write_protect(large): spte %p %llx %lld\n", spte, *spte, gfn);
 660                 if (is_writeble_pte(*spte)) {
 661                         rmap_remove(kvm, spte);
 662                         --kvm->stat.lpages;
 663                         set_shadow_pte(spte, shadow_trap_nonpresent_pte);
 664                         spte = NULL;
 665                         write_protected = 1;
 666                 }
 667                 spte = rmap_next(kvm, rmapp, spte);
 668         }
 669
 670         if (write_protected)
 671                 kvm_flush_remote_tlbs(kvm);
 672 }
 673
 674 static int kvm_unmap_rmapp(struct kvm *kvm, unsigned long *rmapp)
 675 {
 676         u64 *spte;
 677         int need_tlb_flush = 0;
 678
 679         while ((spte = rmap_next(kvm, rmapp, NULL))) {
 680                 BUG_ON(!(*spte & PT_PRESENT_MASK));
 681                 rmap_printk("kvm_rmap_unmap_hva: spte %p %llx\n", spte, *spte);
 682                 rmap_remove(kvm, spte);
 683                 set_shadow_pte(spte, shadow_trap_nonpresent_pte);
 684                 need_tlb_flush = 1;
 685         }
 686         return need_tlb_flush;
 687 }
 688
 689 static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
 690                           int (*handler)(struct kvm *kvm, unsigned long *rmapp))
 691 {
 692         int i;
 693         int retval = 0;
 694
 695         /*
 696          * If mmap_sem isn't taken, we can look the memslots with only
 697          * the mmu_lock by skipping over the slots with userspace_addr == 0.
 698          */
 699         for (i = 0; i < kvm->nmemslots; i++) {
 700                 struct kvm_memory_slot *memslot = &kvm->memslots[i];
 701                 unsigned long start = memslot->userspace_addr;
 702                 unsigned long end;
 703
 704                 /* mmu_lock protects userspace_addr */
 705                 if (!start)
 706                         continue;
 707
 708                 end = start + (memslot->npages << PAGE_SHIFT);
 709                 if (hva >= start && hva < end) {
 710                         gfn_t gfn_offset = (hva - start) >> PAGE_SHIFT;
 711                         retval |= handler(kvm, &memslot->rmap[gfn_offset]);
 712                         retval |= handler(kvm,
 713                                           &memslot->lpage_info[
 714                                                   gfn_offset /
 715                                                   KVM_PAGES_PER_HPAGE].rmap_pde);
 716                 }
 717         }
 718
 719         return retval;
 720 }
 721
 722 int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
 723 {
 724         return kvm_handle_hva(kvm, hva, kvm_unmap_rmapp);
 725 }
 726
 727 static int kvm_age_rmapp(struct kvm *kvm, unsigned long *rmapp)
 728 {
 729         u64 *spte;
 730         int young = 0;
 731
 732         /* always return old for EPT */
 733         if (!shadow_accessed_mask)
 734                 return 0;
 735
 736         spte = rmap_next(kvm, rmapp, NULL);
 737         while (spte) {
 738                 int _young;
 739                 u64 _spte = *spte;
 740                 BUG_ON(!(_spte & PT_PRESENT_MASK));
 741                 _young = _spte & PT_ACCESSED_MASK;
 742                 if (_young) {
 743                         young = 1;
 744                         clear_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte);
 745                 }
 746                 spte = rmap_next(kvm, rmapp, spte);
 747         }
 748         return young;
 749 }
 750
 751 int kvm_age_hva(struct kvm *kvm, unsigned long hva)
 752 {
 753         return kvm_handle_hva(kvm, hva, kvm_age_rmapp);
 754 }
 755
 756 #ifdef MMU_DEBUG
 757 static int is_empty_shadow_page(u64 *spt)
 758 {
 759         u64 *pos;
 760         u64 *end;
 761
 762         for (pos = spt, end = pos + PAGE_SIZE / sizeof(u64); pos != end; pos++)
 763                 if (is_shadow_present_pte(*pos)) {
 764                         printk(KERN_ERR "%s: %p %llx\n", __func__,
 765                                pos, *pos);
 766                         return 0;
 767                 }
 768         return 1;
 769 }
 770 #endif
 771
 772 static void kvm_mmu_free_page(struct kvm *kvm, struct kvm_mmu_page *sp)
 773 {
 774         ASSERT(is_empty_shadow_page(sp->spt));
 775         list_del(&sp->link);
 776         __free_page(virt_to_page(sp->spt));
 777         __free_page(virt_to_page(sp->gfns));
 778         kfree(sp);
 779         ++kvm->arch.n_free_mmu_pages;
 780 }
 781
 782 static unsigned kvm_page_table_hashfn(gfn_t gfn)
 783 {
 784         return gfn & ((1 << KVM_MMU_HASH_SHIFT) - 1);
 785 }
 786
 787 static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu,
 788                                                u64 *parent_pte)
 789 {
 790         struct kvm_mmu_page *sp;
 791
 792         sp = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache, sizeof *sp);
 793         sp->spt = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
 794         sp->gfns = mmu_memory_cache_alloc(&vcpu->arch.mmu_page_cache, PAGE_SIZE);
 795         set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
 796         list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages);
 797         ASSERT(is_empty_shadow_page(sp->spt));
 798         bitmap_zero(sp->slot_bitmap, KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS);
 799         sp->multimapped = 0;
 800         sp->parent_pte = parent_pte;
 801         --vcpu->kvm->arch.n_free_mmu_pages;
 802         return sp;
 803 }
 804
 805 static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu,
 806                                     struct kvm_mmu_page *sp, u64 *parent_pte)
 807 {
 808         struct kvm_pte_chain *pte_chain;
 809         struct hlist_node *node;
 810         int i;
 811
 812         if (!parent_pte)
 813                 return;
 814         if (!sp->multimapped) {
 815                 u64 *old = sp->parent_pte;
 816
 817                 if (!old) {
 818                         sp->parent_pte = parent_pte;
 819                         return;
 820                 }
 821                 sp->multimapped = 1;
 822                 pte_chain = mmu_alloc_pte_chain(vcpu);
 823                 INIT_HLIST_HEAD(&sp->parent_ptes);
 824                 hlist_add_head(&pte_chain->link, &sp->parent_ptes);
 825                 pte_chain->parent_ptes[0] = old;
 826         }
 827         hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link) {
 828                 if (pte_chain->parent_ptes[NR_PTE_CHAIN_ENTRIES-1])
 829                         continue;
 830                 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i)
 831                         if (!pte_chain->parent_ptes[i]) {
 832                                 pte_chain->parent_ptes[i] = parent_pte;
 833                                 return;
 834                         }
 835         }
 836         pte_chain = mmu_alloc_pte_chain(vcpu);
 837         BUG_ON(!pte_chain);
 838         hlist_add_head(&pte_chain->link, &sp->parent_ptes);
 839         pte_chain->parent_ptes[0] = parent_pte;
 840 }
 841
 842 static void mmu_page_remove_parent_pte(struct kvm_mmu_page *sp,
 843                                        u64 *parent_pte)
 844 {
 845         struct kvm_pte_chain *pte_chain;
 846         struct hlist_node *node;
 847         int i;
 848
 849         if (!sp->multimapped) {
 850                 BUG_ON(sp->parent_pte != parent_pte);
 851                 sp->parent_pte = NULL;
 852                 return;
 853         }
 854         hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
 855                 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
 856                         if (!pte_chain->parent_ptes[i])
 857                                 break;
 858                         if (pte_chain->parent_ptes[i] != parent_pte)
 859                                 continue;
 860                         while (i + 1 < NR_PTE_CHAIN_ENTRIES
 861                                 && pte_chain->parent_ptes[i + 1]) {
 862                                 pte_chain->parent_ptes[i]
 863                                         = pte_chain->parent_ptes[i + 1];
 864                                 ++i;
 865                         }
 866                         pte_chain->parent_ptes[i] = NULL;
 867                         if (i == 0) {
 868                                 hlist_del(&pte_chain->link);
 869                                 mmu_free_pte_chain(pte_chain);
 870                                 if (hlist_empty(&sp->parent_ptes)) {
 871                                         sp->multimapped = 0;
 872                                         sp->parent_pte = NULL;
 873                                 }
 874                         }
 875                         return;
 876                 }
 877         BUG();
 878 }
 879
 880
 881 static void mmu_parent_walk(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
 882                             mmu_parent_walk_fn fn)
 883 {
 884         struct kvm_pte_chain *pte_chain;
 885         struct hlist_node *node;
 886         struct kvm_mmu_page *parent_sp;
 887         int i;
 888
 889         if (!sp->multimapped && sp->parent_pte) {
 890                 parent_sp = page_header(__pa(sp->parent_pte));
 891                 fn(vcpu, parent_sp);
 892                 mmu_parent_walk(vcpu, parent_sp, fn);
 893                 return;
 894         }
 895         hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
 896                 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
 897                         if (!pte_chain->parent_ptes[i])
 898                                 break;
 899                         parent_sp = page_header(__pa(pte_chain->parent_ptes[i]));
 900                         fn(vcpu, parent_sp);
 901                         mmu_parent_walk(vcpu, parent_sp, fn);
 902                 }
 903 }
 904
 905 static void kvm_mmu_update_unsync_bitmap(u64 *spte)
 906 {
 907         unsigned int index;
 908         struct kvm_mmu_page *sp = page_header(__pa(spte));
 909
 910         index = spte - sp->spt;
 911         __set_bit(index, sp->unsync_child_bitmap);
 912         sp->unsync_children = 1;
 913 }
 914
 915 static void kvm_mmu_update_parents_unsync(struct kvm_mmu_page *sp)
 916 {
 917         struct kvm_pte_chain *pte_chain;
 918         struct hlist_node *node;
 919         int i;
 920
 921         if (!sp->parent_pte)
 922                 return;
 923
 924         if (!sp->multimapped) {
 925                 kvm_mmu_update_unsync_bitmap(sp->parent_pte);
 926                 return;
 927         }
 928
 929         hlist_for_each_entry(pte_chain, node, &sp->parent_ptes, link)
 930                 for (i = 0; i < NR_PTE_CHAIN_ENTRIES; ++i) {
 931                         if (!pte_chain->parent_ptes[i])
 932                                 break;
 933                         kvm_mmu_update_unsync_bitmap(pte_chain->parent_ptes[i]);
 934                 }
 935 }
 936
 937 static int unsync_walk_fn(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
 938 {
 939         sp->unsync_children = 1;
 940         kvm_mmu_update_parents_unsync(sp);
 941         return 1;
 942 }
 943
 944 static void kvm_mmu_mark_parents_unsync(struct kvm_vcpu *vcpu,
 945                                         struct kvm_mmu_page *sp)
 946 {
 947         mmu_parent_walk(vcpu, sp, unsync_walk_fn);
 948         kvm_mmu_update_parents_unsync(sp);
 949 }
 950
 951 static void nonpaging_prefetch_page(struct kvm_vcpu *vcpu,
 952                                     struct kvm_mmu_page *sp)
 953 {
 954         int i;
 955
 956         for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
 957                 sp->spt[i] = shadow_trap_nonpresent_pte;
 958 }
 959
 960 static int nonpaging_sync_page(struct kvm_vcpu *vcpu,
 961                                struct kvm_mmu_page *sp)
 962 {
 963         return 1;
 964 }
 965
 966 static void nonpaging_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
 967 {
 968 }
 969
 970 #define for_each_unsync_children(bitmap, idx)           \
 971         for (idx = find_first_bit(bitmap, 512);         \
 972              idx < 512;                                 \
 973              idx = find_next_bit(bitmap, 512, idx+1))
 974
 975 static int mmu_unsync_walk(struct kvm_mmu_page *sp,
 976                            struct kvm_unsync_walk *walker)
 977 {
 978         int i, ret;
 979
 980         if (!sp->unsync_children)
 981                 return 0;
 982
 983         for_each_unsync_children(sp->unsync_child_bitmap, i) {
 984                 u64 ent = sp->spt[i];
 985
 986                 if (is_shadow_present_pte(ent)) {
 987                         struct kvm_mmu_page *child;
 988                         child = page_header(ent & PT64_BASE_ADDR_MASK);
 989
 990                         if (child->unsync_children) {
 991                                 ret = mmu_unsync_walk(child, walker);
 992                                 if (ret)
 993                                         return ret;
 994                                 __clear_bit(i, sp->unsync_child_bitmap);
 995                         }
 996
 997                         if (child->unsync) {
 998                                 ret = walker->entry(child, walker);
 999                                 __clear_bit(i, sp->unsync_child_bitmap);
1000                                 if (ret)
1001                                         return ret;
1002                         }
1003                 }
1004         }
1005
1006         if (find_first_bit(sp->unsync_child_bitmap, 512) == 512)
1007                 sp->unsync_children = 0;
1008
1009         return 0;
1010 }
1011
1012 static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm *kvm, gfn_t gfn)
1013 {
1014         unsigned index;
1015         struct hlist_head *bucket;
1016         struct kvm_mmu_page *sp;
1017         struct hlist_node *node;
1018
1019         pgprintk("%s: looking for gfn %lx\n", __func__, gfn);
1020         index = kvm_page_table_hashfn(gfn);
1021         bucket = &kvm->arch.mmu_page_hash[index];
1022         hlist_for_each_entry(sp, node, bucket, hash_link)
1023                 if (sp->gfn == gfn && !sp->role.metaphysical
1024                     && !sp->role.invalid) {
1025                         pgprintk("%s: found role %x\n",
1026                                  __func__, sp->role.word);
1027                         return sp;
1028                 }
1029         return NULL;
1030 }
1031
1032 static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
1033 {
1034         WARN_ON(!sp->unsync);
1035         sp->unsync = 0;
1036         --kvm->stat.mmu_unsync;
1037 }
1038
1039 static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp);
1040
1041 static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
1042 {
1043         if (sp->role.glevels != vcpu->arch.mmu.root_level) {
1044                 kvm_mmu_zap_page(vcpu->kvm, sp);
1045                 return 1;
1046         }
1047
1048         rmap_write_protect(vcpu->kvm, sp->gfn);
1049         kvm_unlink_unsync_page(vcpu->kvm, sp);
1050         if (vcpu->arch.mmu.sync_page(vcpu, sp)) {
1051                 kvm_mmu_zap_page(vcpu->kvm, sp);
1052                 return 1;
1053         }
1054
1055         kvm_mmu_flush_tlb(vcpu);
1056         return 0;
1057 }
1058
1059 struct sync_walker {
1060         struct kvm_vcpu *vcpu;
1061         struct kvm_unsync_walk walker;
1062 };
1063
1064 static int mmu_sync_fn(struct kvm_mmu_page *sp, struct kvm_unsync_walk *walk)
1065 {
1066         struct sync_walker *sync_walk = container_of(walk, struct sync_walker,
1067                                                      walker);
1068         struct kvm_vcpu *vcpu = sync_walk->vcpu;
1069
1070         kvm_sync_page(vcpu, sp);
1071         return (need_resched() || spin_needbreak(&vcpu->kvm->mmu_lock));
1072 }
1073
1074 static void mmu_sync_children(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
1075 {
1076         struct sync_walker walker = {
1077                 .walker = { .entry = mmu_sync_fn, },
1078                 .vcpu = vcpu,
1079         };
1080
1081         while (mmu_unsync_walk(sp, &walker.walker))
1082                 cond_resched_lock(&vcpu->kvm->mmu_lock);
1083 }
1084
1085 static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
1086                                              gfn_t gfn,
1087                                              gva_t gaddr,
1088                                              unsigned level,
1089                                              int metaphysical,
1090                                              unsigned access,
1091                                              u64 *parent_pte)
1092 {
1093         union kvm_mmu_page_role role;
1094         unsigned index;
1095         unsigned quadrant;
1096         struct hlist_head *bucket;
1097         struct kvm_mmu_page *sp;
1098         struct hlist_node *node, *tmp;
1099
1100         role.word = 0;
1101         role.glevels = vcpu->arch.mmu.root_level;
1102         role.level = level;
1103         role.metaphysical = metaphysical;
1104         role.access = access;
1105         if (vcpu->arch.mmu.root_level <= PT32_ROOT_LEVEL) {
1106                 quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
1107                 quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
1108                 role.quadrant = quadrant;
1109         }
1110         pgprintk("%s: looking gfn %lx role %x\n", __func__,
1111                  gfn, role.word);
1112         index = kvm_page_table_hashfn(gfn);
1113         bucket = &vcpu->kvm->arch.mmu_page_hash[index];
1114         hlist_for_each_entry_safe(sp, node, tmp, bucket, hash_link)
1115                 if (sp->gfn == gfn) {
1116                         if (sp->unsync)
1117                                 if (kvm_sync_page(vcpu, sp))
1118                                         continue;
1119
1120                         if (sp->role.word != role.word)
1121                                 continue;
1122
1123                         mmu_page_add_parent_pte(vcpu, sp, parent_pte);
1124                         if (sp->unsync_children) {
1125                                 set_bit(KVM_REQ_MMU_SYNC, &vcpu->requests);
1126                                 kvm_mmu_mark_parents_unsync(vcpu, sp);
1127                         }
1128                         pgprintk("%s: found\n", __func__);
1129                         return sp;
1130                 }
1131         ++vcpu->kvm->stat.mmu_cache_miss;
1132         sp = kvm_mmu_alloc_page(vcpu, parent_pte);
1133         if (!sp)
1134                 return sp;
1135         pgprintk("%s: adding gfn %lx role %x\n", __func__, gfn, role.word);
1136         sp->gfn = gfn;
1137         sp->role = role;
1138         hlist_add_head(&sp->hash_link, bucket);
1139         if (!metaphysical) {
1140                 rmap_write_protect(vcpu->kvm, gfn);
1141                 account_shadowed(vcpu->kvm, gfn);
1142         }
1143         if (shadow_trap_nonpresent_pte != shadow_notrap_nonpresent_pte)
1144                 vcpu->arch.mmu.prefetch_page(vcpu, sp);
1145         else
1146                 nonpaging_prefetch_page(vcpu, sp);
1147         return sp;
1148 }
1149
1150 static int walk_shadow(struct kvm_shadow_walk *walker,
1151                        struct kvm_vcpu *vcpu, u64 addr)
1152 {
1153         hpa_t shadow_addr;
1154         int level;
1155         int r;
1156         u64 *sptep;
1157         unsigned index;
1158
1159         shadow_addr = vcpu->arch.mmu.root_hpa;
1160         level = vcpu->arch.mmu.shadow_root_level;
1161         if (level == PT32E_ROOT_LEVEL) {
1162                 shadow_addr = vcpu->arch.mmu.pae_root[(addr >> 30) & 3];
1163                 shadow_addr &= PT64_BASE_ADDR_MASK;
1164                 --level;
1165         }
1166
1167         while (level >= PT_PAGE_TABLE_LEVEL) {
1168                 index = SHADOW_PT_INDEX(addr, level);
1169                 sptep = ((u64 *)__va(shadow_addr)) + index;
1170                 r = walker->entry(walker, vcpu, addr, sptep, level);
1171                 if (r)
1172                         return r;
1173                 shadow_addr = *sptep & PT64_BASE_ADDR_MASK;
1174                 --level;
1175         }
1176         return 0;
1177 }
1178
1179 static void kvm_mmu_page_unlink_children(struct kvm *kvm,
1180                                          struct kvm_mmu_page *sp)
1181 {
1182         unsigned i;
1183         u64 *pt;
1184         u64 ent;
1185
1186         pt = sp->spt;
1187
1188         if (sp->role.level == PT_PAGE_TABLE_LEVEL) {
1189                 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
1190                         if (is_shadow_present_pte(pt[i]))
1191                                 rmap_remove(kvm, &pt[i]);
1192                         pt[i] = shadow_trap_nonpresent_pte;
1193                 }
1194                 return;
1195         }
1196
1197         for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
1198                 ent = pt[i];
1199
1200                 if (is_shadow_present_pte(ent)) {
1201                         if (!is_large_pte(ent)) {
1202                                 ent &= PT64_BASE_ADDR_MASK;
1203                                 mmu_page_remove_parent_pte(page_header(ent),
1204                                                            &pt[i]);
1205                         } else {
1206                                 --kvm->stat.lpages;
1207                                 rmap_remove(kvm, &pt[i]);
1208                         }
1209                 }
1210                 pt[i] = shadow_trap_nonpresent_pte;
1211         }
1212 }
1213
1214 static void kvm_mmu_put_page(struct kvm_mmu_page *sp, u64 *parent_pte)
1215 {
1216         mmu_page_remove_parent_pte(sp, parent_pte);
1217 }
1218
1219 static void kvm_mmu_reset_last_pte_updated(struct kvm *kvm)
1220 {
1221         int i;
1222
1223         for (i = 0; i < KVM_MAX_VCPUS; ++i)
1224                 if (kvm->vcpus[i])
1225                         kvm->vcpus[i]->arch.last_pte_updated = NULL;
1226 }
1227
1228 static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp)
1229 {
1230         u64 *parent_pte;
1231
1232         while (sp->multimapped || sp->parent_pte) {
1233                 if (!sp->multimapped)
1234                         parent_pte = sp->parent_pte;
1235                 else {
1236                         struct kvm_pte_chain *chain;
1237
1238                         chain = container_of(sp->parent_ptes.first,
1239                                              struct kvm_pte_chain, link);
1240                         parent_pte = chain->parent_ptes[0];
1241                 }
1242                 BUG_ON(!parent_pte);
1243                 kvm_mmu_put_page(sp, parent_pte);
1244                 set_shadow_pte(parent_pte, shadow_trap_nonpresent_pte);
1245         }
1246 }
1247
1248 struct zap_walker {
1249         struct kvm_unsync_walk walker;
1250         struct kvm *kvm;
1251         int zapped;
1252 };
1253
1254 static int mmu_zap_fn(struct kvm_mmu_page *sp, struct kvm_unsync_walk *walk)
1255 {
1256         struct zap_walker *zap_walk = container_of(walk, struct zap_walker,
1257                                                      walker);
1258         kvm_mmu_zap_page(zap_walk->kvm, sp);
1259         zap_walk->zapped = 1;
1260         return 0;
1261 }
1262
1263 static int mmu_zap_unsync_children(struct kvm *kvm, struct kvm_mmu_page *sp)
1264 {
1265         struct zap_walker walker = {
1266                 .walker = { .entry = mmu_zap_fn, },
1267                 .kvm = kvm,
1268                 .zapped = 0,
1269         };
1270
1271         if (sp->role.level == PT_PAGE_TABLE_LEVEL)
1272                 return 0;
1273         mmu_unsync_walk(sp, &walker.walker);
1274         return walker.zapped;
1275 }
1276
1277 static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp)
1278 {
1279         int ret;
1280         ++kvm->stat.mmu_shadow_zapped;
1281         ret = mmu_zap_unsync_children(kvm, sp);
1282         kvm_mmu_page_unlink_children(kvm, sp);
1283         kvm_mmu_unlink_parents(kvm, sp);
1284         kvm_flush_remote_tlbs(kvm);
1285         if (!sp->role.invalid && !sp->role.metaphysical)
1286                 unaccount_shadowed(kvm, sp->gfn);
1287         if (sp->unsync)
1288                 kvm_unlink_unsync_page(kvm, sp);
1289         if (!sp->root_count) {
1290                 hlist_del(&sp->hash_link);
1291                 kvm_mmu_free_page(kvm, sp);
1292         } else {
1293                 sp->role.invalid = 1;
1294                 list_move(&sp->link, &kvm->arch.active_mmu_pages);
1295                 kvm_reload_remote_mmus(kvm);
1296         }
1297         kvm_mmu_reset_last_pte_updated(kvm);
1298         return ret;
1299 }
1300
1301 /*
1302  * Changing the number of mmu pages allocated to the vm
1303  * Note: if kvm_nr_mmu_pages is too small, you will get dead lock
1304  */
1305 void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages)
1306 {
1307         /*
1308          * If we set the number of mmu pages to be smaller be than the
1309          * number of actived pages , we must to free some mmu pages before we
1310          * change the value
1311          */
1312
1313         if ((kvm->arch.n_alloc_mmu_pages - kvm->arch.n_free_mmu_pages) >
1314             kvm_nr_mmu_pages) {
1315                 int n_used_mmu_pages = kvm->arch.n_alloc_mmu_pages
1316                                        - kvm->arch.n_free_mmu_pages;
1317
1318                 while (n_used_mmu_pages > kvm_nr_mmu_pages) {
1319                         struct kvm_mmu_page *page;
1320
1321                         page = container_of(kvm->arch.active_mmu_pages.prev,
1322                                             struct kvm_mmu_page, link);
1323                         kvm_mmu_zap_page(kvm, page);
1324                         n_used_mmu_pages--;
1325                 }
1326                 kvm->arch.n_free_mmu_pages = 0;
1327         }
1328         else
1329                 kvm->arch.n_free_mmu_pages += kvm_nr_mmu_pages
1330                                          - kvm->arch.n_alloc_mmu_pages;
1331
1332         kvm->arch.n_alloc_mmu_pages = kvm_nr_mmu_pages;
1333 }
1334
1335 static int kvm_mmu_unprotect_page(struct kvm *kvm, gfn_t gfn)
1336 {
1337         unsigned index;
1338         struct hlist_head *bucket;
1339         struct kvm_mmu_page *sp;
1340         struct hlist_node *node, *n;
1341         int r;
1342
1343         pgprintk("%s: looking for gfn %lx\n", __func__, gfn);
1344         r = 0;
1345         index = kvm_page_table_hashfn(gfn);
1346         bucket = &kvm->arch.mmu_page_hash[index];
1347         hlist_for_each_entry_safe(sp, node, n, bucket, hash_link)
1348                 if (sp->gfn == gfn && !sp->role.metaphysical) {
1349                         pgprintk("%s: gfn %lx role %x\n", __func__, gfn,
1350                                  sp->role.word);
1351                         r = 1;
1352                         if (kvm_mmu_zap_page(kvm, sp))
1353                                 n = bucket->first;
1354                 }
1355         return r;
1356 }
1357
1358 static void mmu_unshadow(struct kvm *kvm, gfn_t gfn)
1359 {
1360         struct kvm_mmu_page *sp;
1361
1362         while ((sp = kvm_mmu_lookup_page(kvm, gfn)) != NULL) {
1363                 pgprintk("%s: zap %lx %x\n", __func__, gfn, sp->role.word);
1364                 kvm_mmu_zap_page(kvm, sp);
1365         }
1366 }
1367
1368 static void page_header_update_slot(struct kvm *kvm, void *pte, gfn_t gfn)
1369 {
1370         int slot = memslot_id(kvm, gfn_to_memslot(kvm, gfn));
1371         struct kvm_mmu_page *sp = page_header(__pa(pte));
1372
1373         __set_bit(slot, sp->slot_bitmap);
1374 }
1375
1376 static void mmu_convert_notrap(struct kvm_mmu_page *sp)
1377 {
1378         int i;
1379         u64 *pt = sp->spt;
1380
1381         if (shadow_trap_nonpresent_pte == shadow_notrap_nonpresent_pte)
1382                 return;
1383
1384         for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
1385                 if (pt[i] == shadow_notrap_nonpresent_pte)
1386                         set_shadow_pte(&pt[i], shadow_trap_nonpresent_pte);
1387         }
1388 }
1389
1390 struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t gva)
1391 {
1392         struct page *page;
1393
1394         gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva);
1395
1396         if (gpa == UNMAPPED_GVA)
1397                 return NULL;
1398
1399         page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT);
1400
1401         return page;
1402 }
1403
1404 /*
1405  * The function is based on mtrr_type_lookup() in
1406  * arch/x86/kernel/cpu/mtrr/generic.c
1407  */
1408 static int get_mtrr_type(struct mtrr_state_type *mtrr_state,
1409                          u64 start, u64 end)
1410 {
1411         int i;
1412         u64 base, mask;
1413         u8 prev_match, curr_match;
1414         int num_var_ranges = KVM_NR_VAR_MTRR;
1415
1416         if (!mtrr_state->enabled)
1417                 return 0xFF;
1418
1419         /* Make end inclusive end, instead of exclusive */
1420         end--;
1421
1422         /* Look in fixed ranges. Just return the type as per start */
1423         if (mtrr_state->have_fixed && (start < 0x100000)) {
1424                 int idx;
1425
1426                 if (start < 0x80000) {
1427                         idx = 0;
1428                         idx += (start >> 16);
1429                         return mtrr_state->fixed_ranges[idx];
1430                 } else if (start < 0xC0000) {
1431                         idx = 1 * 8;
1432                         idx += ((start - 0x80000) >> 14);
1433                         return mtrr_state->fixed_ranges[idx];
1434                 } else if (start < 0x1000000) {
1435                         idx = 3 * 8;
1436                         idx += ((start - 0xC0000) >> 12);
1437                         return mtrr_state->fixed_ranges[idx];
1438                 }
1439         }
1440
1441         /*
1442          * Look in variable ranges
1443          * Look of multiple ranges matching this address and pick type
1444          * as per MTRR precedence
1445          */
1446         if (!(mtrr_state->enabled & 2))
1447                 return mtrr_state->def_type;
1448
1449         prev_match = 0xFF;
1450         for (i = 0; i < num_var_ranges; ++i) {
1451                 unsigned short start_state, end_state;
1452
1453                 if (!(mtrr_state->var_ranges[i].mask_lo & (1 << 11)))
1454                         continue;
1455
1456                 base = (((u64)mtrr_state->var_ranges[i].base_hi) << 32) +
1457                        (mtrr_state->var_ranges[i].base_lo & PAGE_MASK);
1458                 mask = (((u64)mtrr_state->var_ranges[i].mask_hi) << 32) +
1459                        (mtrr_state->var_ranges[i].mask_lo & PAGE_MASK);
1460
1461                 start_state = ((start & mask) == (base & mask));
1462                 end_state = ((end & mask) == (base & mask));
1463                 if (start_state != end_state)
1464                         return 0xFE;
1465
1466                 if ((start & mask) != (base & mask))
1467                         continue;
1468
1469                 curr_match = mtrr_state->var_ranges[i].base_lo & 0xff;
1470                 if (prev_match == 0xFF) {
1471                         prev_match = curr_match;
1472                         continue;
1473                 }
1474
1475                 if (prev_match == MTRR_TYPE_UNCACHABLE ||
1476                     curr_match == MTRR_TYPE_UNCACHABLE)
1477                         return MTRR_TYPE_UNCACHABLE;
1478
1479                 if ((prev_match == MTRR_TYPE_WRBACK &&
1480                      curr_match == MTRR_TYPE_WRTHROUGH) ||
1481                     (prev_match == MTRR_TYPE_WRTHROUGH &&
1482                      curr_match == MTRR_TYPE_WRBACK)) {
1483                         prev_match = MTRR_TYPE_WRTHROUGH;
1484                         curr_match = MTRR_TYPE_WRTHROUGH;
1485                 }
1486
1487                 if (prev_match != curr_match)
1488                         return MTRR_TYPE_UNCACHABLE;
1489         }
1490
1491         if (prev_match != 0xFF)
1492                 return prev_match;
1493
1494         return mtrr_state->def_type;
1495 }
1496
1497 static u8 get_memory_type(struct kvm_vcpu *vcpu, gfn_t gfn)
1498 {
1499         u8 mtrr;
1500
1501         mtrr = get_mtrr_type(&vcpu->arch.mtrr_state, gfn << PAGE_SHIFT,
1502                              (gfn << PAGE_SHIFT) + PAGE_SIZE);
1503         if (mtrr == 0xfe || mtrr == 0xff)
1504                 mtrr = MTRR_TYPE_WRBACK;
1505         return mtrr;
1506 }
1507
1508 static int kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
1509 {
1510         unsigned index;
1511         struct hlist_head *bucket;
1512         struct kvm_mmu_page *s;
1513         struct hlist_node *node, *n;
1514
1515         index = kvm_page_table_hashfn(sp->gfn);
1516         bucket = &vcpu->kvm->arch.mmu_page_hash[index];
1517         /* don't unsync if pagetable is shadowed with multiple roles */
1518         hlist_for_each_entry_safe(s, node, n, bucket, hash_link) {
1519                 if (s->gfn != sp->gfn || s->role.metaphysical)
1520                         continue;
1521                 if (s->role.word != sp->role.word)
1522                         return 1;
1523         }
1524         kvm_mmu_mark_parents_unsync(vcpu, sp);
1525         ++vcpu->kvm->stat.mmu_unsync;
1526         sp->unsync = 1;
1527         mmu_convert_notrap(sp);
1528         return 0;
1529 }
1530
1531 static int mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn,
1532                                   bool can_unsync)
1533 {
1534         struct kvm_mmu_page *shadow;
1535
1536         shadow = kvm_mmu_lookup_page(vcpu->kvm, gfn);
1537         if (shadow) {
1538                 if (shadow->role.level != PT_PAGE_TABLE_LEVEL)
1539                         return 1;
1540                 if (shadow->unsync)
1541                         return 0;
1542                 if (can_unsync && oos_shadow)
1543                         return kvm_unsync_page(vcpu, shadow);
1544                 return 1;
1545         }
1546         return 0;
1547 }
1548
1549 static int set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
1550                     unsigned pte_access, int user_fault,
1551                     int write_fault, int dirty, int largepage,
1552                     gfn_t gfn, pfn_t pfn, bool speculative,
1553                     bool can_unsync)
1554 {
1555         u64 spte;
1556         int ret = 0;
1557         u64 mt_mask = shadow_mt_mask;
1558
1559         /*
1560          * We don't set the accessed bit, since we sometimes want to see
1561          * whether the guest actually used the pte (in order to detect
1562          * demand paging).
1563          */
1564         spte = shadow_base_present_pte | shadow_dirty_mask;
1565         if (!speculative)
1566                 spte |= shadow_accessed_mask;
1567         if (!dirty)
1568                 pte_access &= ~ACC_WRITE_MASK;
1569         if (pte_access & ACC_EXEC_MASK)
1570                 spte |= shadow_x_mask;
1571         else
1572                 spte |= shadow_nx_mask;
1573         if (pte_access & ACC_USER_MASK)
1574                 spte |= shadow_user_mask;
1575         if (largepage)
1576                 spte |= PT_PAGE_SIZE_MASK;
1577         if (mt_mask) {
1578                 mt_mask = get_memory_type(vcpu, gfn) <<
1579                           kvm_x86_ops->get_mt_mask_shift();
1580                 spte |= mt_mask;
1581         }
1582
1583         spte |= (u64)pfn << PAGE_SHIFT;
1584
1585         if ((pte_access & ACC_WRITE_MASK)
1586             || (write_fault && !is_write_protection(vcpu) && !user_fault)) {
1587
1588                 if (largepage && has_wrprotected_page(vcpu->kvm, gfn)) {
1589                         ret = 1;
1590                         spte = shadow_trap_nonpresent_pte;
1591                         goto set_pte;
1592                 }
1593
1594                 spte |= PT_WRITABLE_MASK;
1595
1596                 /*
1597                  * Optimization: for pte sync, if spte was writable the hash
1598                  * lookup is unnecessary (and expensive). Write protection
1599                  * is responsibility of mmu_get_page / kvm_sync_page.
1600                  * Same reasoning can be applied to dirty page accounting.
1601                  */
1602                 if (!can_unsync && is_writeble_pte(*shadow_pte))
1603                         goto set_pte;
1604
1605                 if (mmu_need_write_protect(vcpu, gfn, can_unsync)) {
1606                         pgprintk("%s: found shadow page for %lx, marking ro\n",
1607                                  __func__, gfn);
1608                         ret = 1;
1609                         pte_access &= ~ACC_WRITE_MASK;
1610                         if (is_writeble_pte(spte))
1611                                 spte &= ~PT_WRITABLE_MASK;
1612                 }
1613         }
1614
1615         if (pte_access & ACC_WRITE_MASK)
1616                 mark_page_dirty(vcpu->kvm, gfn);
1617
1618 set_pte:
1619         set_shadow_pte(shadow_pte, spte);
1620         return ret;
1621 }
1622
1623 static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
1624                          unsigned pt_access, unsigned pte_access,
1625                          int user_fault, int write_fault, int dirty,
1626                          int *ptwrite, int largepage, gfn_t gfn,
1627                          pfn_t pfn, bool speculative)
1628 {
1629         int was_rmapped = 0;
1630         int was_writeble = is_writeble_pte(*shadow_pte);
1631
1632         pgprintk("%s: spte %llx access %x write_fault %d"
1633                  " user_fault %d gfn %lx\n",
1634                  __func__, *shadow_pte, pt_access,
1635                  write_fault, user_fault, gfn);
1636
1637         if (is_rmap_pte(*shadow_pte)) {
1638                 /*
1639                  * If we overwrite a PTE page pointer with a 2MB PMD, unlink
1640                  * the parent of the now unreachable PTE.
1641                  */
1642                 if (largepage && !is_large_pte(*shadow_pte)) {
1643                         struct kvm_mmu_page *child;
1644                         u64 pte = *shadow_pte;
1645
1646                         child = page_header(pte & PT64_BASE_ADDR_MASK);
1647                         mmu_page_remove_parent_pte(child, shadow_pte);
1648                 } else if (pfn != spte_to_pfn(*shadow_pte)) {
1649                         pgprintk("hfn old %lx new %lx\n",
1650                                  spte_to_pfn(*shadow_pte), pfn);
1651                         rmap_remove(vcpu->kvm, shadow_pte);
1652                 } else {
1653                         if (largepage)
1654                                 was_rmapped = is_large_pte(*shadow_pte);
1655                         else
1656                                 was_rmapped = 1;
1657                 }
1658         }
1659         if (set_spte(vcpu, shadow_pte, pte_access, user_fault, write_fault,
1660                       dirty, largepage, gfn, pfn, speculative, true)) {
1661                 if (write_fault)
1662                         *ptwrite = 1;
1663                 kvm_x86_ops->tlb_flush(vcpu);
1664         }
1665
1666         pgprintk("%s: setting spte %llx\n", __func__, *shadow_pte);
1667         pgprintk("instantiating %s PTE (%s) at %ld (%llx) addr %p\n",
1668                  is_large_pte(*shadow_pte)? "2MB" : "4kB",
1669                  is_present_pte(*shadow_pte)?"RW":"R", gfn,
1670                  *shadow_pte, shadow_pte);
1671         if (!was_rmapped && is_large_pte(*shadow_pte))
1672                 ++vcpu->kvm->stat.lpages;
1673
1674         page_header_update_slot(vcpu->kvm, shadow_pte, gfn);
1675         if (!was_rmapped) {
1676                 rmap_add(vcpu, shadow_pte, gfn, largepage);
1677                 if (!is_rmap_pte(*shadow_pte))
1678                         kvm_release_pfn_clean(pfn);
1679         } else {
1680                 if (was_writeble)
1681                         kvm_release_pfn_dirty(pfn);
1682                 else
1683                         kvm_release_pfn_clean(pfn);
1684         }
1685         if (speculative) {
1686                 vcpu->arch.last_pte_updated = shadow_pte;
1687                 vcpu->arch.last_pte_gfn = gfn;
1688         }
1689 }
1690
1691 static void nonpaging_new_cr3(struct kvm_vcpu *vcpu)
1692 {
1693 }
1694
1695 struct direct_shadow_walk {
1696         struct kvm_shadow_walk walker;
1697         pfn_t pfn;
1698         int write;
1699         int largepage;
1700         int pt_write;
1701 };
1702
1703 static int direct_map_entry(struct kvm_shadow_walk *_walk,
1704                             struct kvm_vcpu *vcpu,
1705                             u64 addr, u64 *sptep, int level)
1706 {
1707         struct direct_shadow_walk *walk =
1708                 container_of(_walk, struct direct_shadow_walk, walker);
1709         struct kvm_mmu_page *sp;
1710         gfn_t pseudo_gfn;
1711         gfn_t gfn = addr >> PAGE_SHIFT;
1712
1713         if (level == PT_PAGE_TABLE_LEVEL
1714             || (walk->largepage && level == PT_DIRECTORY_LEVEL)) {
1715                 mmu_set_spte(vcpu, sptep, ACC_ALL, ACC_ALL,
1716                              0, walk->write, 1, &walk->pt_write,
1717                              walk->largepage, gfn, walk->pfn, false);
1718                 ++vcpu->stat.pf_fixed;
1719                 return 1;
1720         }
1721
1722         if (*sptep == shadow_trap_nonpresent_pte) {
1723                 pseudo_gfn = (addr & PT64_DIR_BASE_ADDR_MASK) >> PAGE_SHIFT;
1724                 sp = kvm_mmu_get_page(vcpu, pseudo_gfn, (gva_t)addr, level - 1,
1725                                       1, ACC_ALL, sptep);
1726                 if (!sp) {
1727                         pgprintk("nonpaging_map: ENOMEM\n");
1728                         kvm_release_pfn_clean(walk->pfn);
1729                         return -ENOMEM;
1730                 }
1731
1732                 set_shadow_pte(sptep,
1733                                __pa(sp->spt)
1734                                | PT_PRESENT_MASK | PT_WRITABLE_MASK
1735                                | shadow_user_mask | shadow_x_mask);
1736         }
1737         return 0;
1738 }
1739
1740 static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write,
1741                         int largepage, gfn_t gfn, pfn_t pfn)
1742 {
1743         int r;
1744         struct direct_shadow_walk walker = {
1745                 .walker = { .entry = direct_map_entry, },
1746                 .pfn = pfn,
1747                 .largepage = largepage,
1748                 .write = write,
1749                 .pt_write = 0,
1750         };
1751
1752         r = walk_shadow(&walker.walker, vcpu, gfn << PAGE_SHIFT);
1753         if (r < 0)
1754                 return r;
1755         return walker.pt_write;
1756 }
1757
1758 static int nonpaging_map(struct kvm_vcpu *vcpu, gva_t v, int write, gfn_t gfn)
1759 {
1760         int r;
1761         int largepage = 0;
1762         pfn_t pfn;
1763         unsigned long mmu_seq;
1764
1765         if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
1766                 gfn &= ~(KVM_PAGES_PER_HPAGE-1);
1767                 largepage = 1;
1768         }
1769
1770         mmu_seq = vcpu->kvm->mmu_notifier_seq;
1771         smp_rmb();
1772         pfn = gfn_to_pfn(vcpu->kvm, gfn);
1773
1774         /* mmio */
1775         if (is_error_pfn(pfn)) {
1776                 kvm_release_pfn_clean(pfn);
1777                 return 1;
1778         }
1779
1780         spin_lock(&vcpu->kvm->mmu_lock);
1781         if (mmu_notifier_retry(vcpu, mmu_seq))
1782                 goto out_unlock;
1783         kvm_mmu_free_some_pages(vcpu);
1784         r = __direct_map(vcpu, v, write, largepage, gfn, pfn);
1785         spin_unlock(&vcpu->kvm->mmu_lock);
1786
1787
1788         return r;
1789
1790 out_unlock:
1791         spin_unlock(&vcpu->kvm->mmu_lock);
1792         kvm_release_pfn_clean(pfn);
1793         return 0;
1794 }
1795
1796
1797 static void mmu_free_roots(struct kvm_vcpu *vcpu)
1798 {
1799         int i;
1800         struct kvm_mmu_page *sp;
1801
1802         if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
1803                 return;
1804         spin_lock(&vcpu->kvm->mmu_lock);
1805         if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
1806                 hpa_t root = vcpu->arch.mmu.root_hpa;
1807
1808                 sp = page_header(root);
1809                 --sp->root_count;
1810                 if (!sp->root_count && sp->role.invalid)
1811                         kvm_mmu_zap_page(vcpu->kvm, sp);
1812                 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
1813                 spin_unlock(&vcpu->kvm->mmu_lock);
1814                 return;
1815         }
1816         for (i = 0; i < 4; ++i) {
1817                 hpa_t root = vcpu->arch.mmu.pae_root[i];
1818
1819                 if (root) {
1820                         root &= PT64_BASE_ADDR_MASK;
1821                         sp = page_header(root);
1822                         --sp->root_count;
1823                         if (!sp->root_count && sp->role.invalid)
1824                                 kvm_mmu_zap_page(vcpu->kvm, sp);
1825                 }
1826                 vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
1827         }
1828         spin_unlock(&vcpu->kvm->mmu_lock);
1829         vcpu->arch.mmu.root_hpa = INVALID_PAGE;
1830 }
1831
1832 static void mmu_alloc_roots(struct kvm_vcpu *vcpu)
1833 {
1834         int i;
1835         gfn_t root_gfn;
1836         struct kvm_mmu_page *sp;
1837         int metaphysical = 0;
1838
1839         root_gfn = vcpu->arch.cr3 >> PAGE_SHIFT;
1840
1841         if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
1842                 hpa_t root = vcpu->arch.mmu.root_hpa;
1843
1844                 ASSERT(!VALID_PAGE(root));
1845                 if (tdp_enabled)
1846                         metaphysical = 1;
1847                 sp = kvm_mmu_get_page(vcpu, root_gfn, 0,
1848                                       PT64_ROOT_LEVEL, metaphysical,
1849                                       ACC_ALL, NULL);
1850                 root = __pa(sp->spt);
1851                 ++sp->root_count;
1852                 vcpu->arch.mmu.root_hpa = root;
1853                 return;
1854         }
1855         metaphysical = !is_paging(vcpu);
1856         if (tdp_enabled)
1857                 metaphysical = 1;
1858         for (i = 0; i < 4; ++i) {
1859                 hpa_t root = vcpu->arch.mmu.pae_root[i];
1860
1861                 ASSERT(!VALID_PAGE(root));
1862                 if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
1863                         if (!is_present_pte(vcpu->arch.pdptrs[i])) {
1864                                 vcpu->arch.mmu.pae_root[i] = 0;
1865                                 continue;
1866                         }
1867                         root_gfn = vcpu->arch.pdptrs[i] >> PAGE_SHIFT;
1868                 } else if (vcpu->arch.mmu.root_level == 0)
1869                         root_gfn = 0;
1870                 sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30,
1871                                       PT32_ROOT_LEVEL, metaphysical,
1872                                       ACC_ALL, NULL);
1873                 root = __pa(sp->spt);
1874                 ++sp->root_count;
1875                 vcpu->arch.mmu.pae_root[i] = root | PT_PRESENT_MASK;
1876         }
1877         vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
1878 }
1879
1880 static void mmu_sync_roots(struct kvm_vcpu *vcpu)
1881 {
1882         int i;
1883         struct kvm_mmu_page *sp;
1884
1885         if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
1886                 return;
1887         if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
1888                 hpa_t root = vcpu->arch.mmu.root_hpa;
1889                 sp = page_header(root);
1890                 mmu_sync_children(vcpu, sp);
1891                 return;
1892         }
1893         for (i = 0; i < 4; ++i) {
1894                 hpa_t root = vcpu->arch.mmu.pae_root[i];
1895
1896                 if (root) {
1897                         root &= PT64_BASE_ADDR_MASK;
1898                         sp = page_header(root);
1899                         mmu_sync_children(vcpu, sp);
1900                 }
1901         }
1902 }
1903
1904 void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
1905 {
1906         spin_lock(&vcpu->kvm->mmu_lock);
1907         mmu_sync_roots(vcpu);
1908         spin_unlock(&vcpu->kvm->mmu_lock);
1909 }
1910
1911 static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr)
1912 {
1913         return vaddr;
1914 }
1915
1916 static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
1917                                 u32 error_code)
1918 {
1919         gfn_t gfn;
1920         int r;
1921
1922         pgprintk("%s: gva %lx error %x\n", __func__, gva, error_code);
1923         r = mmu_topup_memory_caches(vcpu);
1924         if (r)
1925                 return r;
1926
1927         ASSERT(vcpu);
1928         ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
1929
1930         gfn = gva >> PAGE_SHIFT;
1931
1932         return nonpaging_map(vcpu, gva & PAGE_MASK,
1933                              error_code & PFERR_WRITE_MASK, gfn);
1934 }
1935
1936 static int tdp_page_fault(struct kvm_vcpu *vcpu, gva_t gpa,
1937                                 u32 error_code)
1938 {
1939         pfn_t pfn;
1940         int r;
1941         int largepage = 0;
1942         gfn_t gfn = gpa >> PAGE_SHIFT;
1943         unsigned long mmu_seq;
1944
1945         ASSERT(vcpu);
1946         ASSERT(VALID_PAGE(vcpu->arch.mmu.root_hpa));
1947
1948         r = mmu_topup_memory_caches(vcpu);
1949         if (r)
1950                 return r;
1951
1952         if (is_largepage_backed(vcpu, gfn & ~(KVM_PAGES_PER_HPAGE-1))) {
1953                 gfn &= ~(KVM_PAGES_PER_HPAGE-1);
1954                 largepage = 1;
1955         }
1956         mmu_seq = vcpu->kvm->mmu_notifier_seq;
1957         smp_rmb();
1958         pfn = gfn_to_pfn(vcpu->kvm, gfn);
1959         if (is_error_pfn(pfn)) {
1960                 kvm_release_pfn_clean(pfn);
1961                 return 1;
1962         }
1963         spin_lock(&vcpu->kvm->mmu_lock);
1964         if (mmu_notifier_retry(vcpu, mmu_seq))
1965                 goto out_unlock;
1966         kvm_mmu_free_some_pages(vcpu);
1967         r = __direct_map(vcpu, gpa, error_code & PFERR_WRITE_MASK,
1968                          largepage, gfn, pfn);
1969         spin_unlock(&vcpu->kvm->mmu_lock);
1970
1971         return r;
1972
1973 out_unlock:
1974         spin_unlock(&vcpu->kvm->mmu_lock);
1975         kvm_release_pfn_clean(pfn);
1976         return 0;
1977 }
1978
1979 static void nonpaging_free(struct kvm_vcpu *vcpu)
1980 {
1981         mmu_free_roots(vcpu);
1982 }
1983
1984 static int nonpaging_init_context(struct kvm_vcpu *vcpu)
1985 {
1986         struct kvm_mmu *context = &vcpu->arch.mmu;
1987
1988         context->new_cr3 = nonpaging_new_cr3;
1989         context->page_fault = nonpaging_page_fault;
1990         context->gva_to_gpa = nonpaging_gva_to_gpa;
1991         context->free = nonpaging_free;
1992         context->prefetch_page = nonpaging_prefetch_page;
1993         context->sync_page = nonpaging_sync_page;
1994         context->invlpg = nonpaging_invlpg;
1995         context->root_level = 0;
1996         context->shadow_root_level = PT32E_ROOT_LEVEL;
1997         context->root_hpa = INVALID_PAGE;
1998         return 0;
1999 }
2000
2001 void kvm_mmu_flush_tlb(struct kvm_vcpu *vcpu)
2002 {
2003         ++vcpu->stat.tlb_flush;
2004         kvm_x86_ops->tlb_flush(vcpu);
2005 }
2006
2007 static void paging_new_cr3(struct kvm_vcpu *vcpu)
2008 {
2009         pgprintk("%s: cr3 %lx\n", __func__, vcpu->arch.cr3);
2010         mmu_free_roots(vcpu);
2011 }
2012
2013 static void inject_page_fault(struct kvm_vcpu *vcpu,
2014                               u64 addr,
2015                               u32 err_code)
2016 {
2017         kvm_inject_page_fault(vcpu, addr, err_code);
2018 }
2019
2020 static void paging_free(struct kvm_vcpu *vcpu)
2021 {
2022         nonpaging_free(vcpu);
2023 }
2024
2025 #define PTTYPE 64
2026 #include "paging_tmpl.h"
2027 #undef PTTYPE
2028
2029 #define PTTYPE 32
2030 #include "paging_tmpl.h"
2031 #undef PTTYPE
2032
2033 static int paging64_init_context_common(struct kvm_vcpu *vcpu, int level)
2034 {
2035         struct kvm_mmu *context = &vcpu->arch.mmu;
2036
2037         ASSERT(is_pae(vcpu));
2038         context->new_cr3 = paging_new_cr3;
2039         context->page_fault = paging64_page_fault;
2040         context->gva_to_gpa = paging64_gva_to_gpa;
2041         context->prefetch_page = paging64_prefetch_page;
2042         context->sync_page = paging64_sync_page;
2043         context->invlpg = paging64_invlpg;
2044         context->free = paging_free;
2045         context->root_level = level;
2046         context->shadow_root_level = level;
2047         context->root_hpa = INVALID_PAGE;
2048         return 0;
2049 }
2050
2051 static int paging64_init_context(struct kvm_vcpu *vcpu)
2052 {
2053         return paging64_init_context_common(vcpu, PT64_ROOT_LEVEL);
2054 }
2055
2056 static int paging32_init_context(struct kvm_vcpu *vcpu)
2057 {
2058         struct kvm_mmu *context = &vcpu->arch.mmu;
2059
2060         context->new_cr3 = paging_new_cr3;
2061         context->page_fault = paging32_page_fault;
2062         context->gva_to_gpa = paging32_gva_to_gpa;
2063         context->free = paging_free;
2064         context->prefetch_page = paging32_prefetch_page;
2065         context->sync_page = paging32_sync_page;
2066         context->invlpg = paging32_invlpg;
2067         context->root_level = PT32_ROOT_LEVEL;
2068         context->shadow_root_level = PT32E_ROOT_LEVEL;
2069         context->root_hpa = INVALID_PAGE;
2070         return 0;
2071 }
2072
2073 static int paging32E_init_context(struct kvm_vcpu *vcpu)
2074 {
2075         return paging64_init_context_common(vcpu, PT32E_ROOT_LEVEL);
2076 }
2077
2078 static int init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
2079 {
2080         struct kvm_mmu *context = &vcpu->arch.mmu;
2081
2082         context->new_cr3 = nonpaging_new_cr3;
2083         context->page_fault = tdp_page_fault;
2084         context->free = nonpaging_free;
2085         context->prefetch_page = nonpaging_prefetch_page;
2086         context->sync_page = nonpaging_sync_page;
2087         context->invlpg = nonpaging_invlpg;
2088         context->shadow_root_level = kvm_x86_ops->get_tdp_level();
2089         context->root_hpa = INVALID_PAGE;
2090
2091         if (!is_paging(vcpu)) {
2092                 context->gva_to_gpa = nonpaging_gva_to_gpa;
2093                 context->root_level = 0;
2094         } else if (is_long_mode(vcpu)) {
2095                 context->gva_to_gpa = paging64_gva_to_gpa;
2096                 context->root_level = PT64_ROOT_LEVEL;
2097         } else if (is_pae(vcpu)) {
2098                 context->gva_to_gpa = paging64_gva_to_gpa;
2099                 context->root_level = PT32E_ROOT_LEVEL;
2100         } else {
2101                 context->gva_to_gpa = paging32_gva_to_gpa;
2102                 context->root_level = PT32_ROOT_LEVEL;
2103         }
2104
2105         return 0;
2106 }
2107
2108 static int init_kvm_softmmu(struct kvm_vcpu *vcpu)
2109 {
2110         ASSERT(vcpu);
2111         ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
2112
2113         if (!is_paging(vcpu))
2114                 return nonpaging_init_context(vcpu);
2115         else if (is_long_mode(vcpu))
2116                 return paging64_init_context(vcpu);
2117         else if (is_pae(vcpu))
2118                 return paging32E_init_context(vcpu);
2119         else
2120                 return paging32_init_context(vcpu);
2121 }
2122
2123 static int init_kvm_mmu(struct kvm_vcpu *vcpu)
2124 {
2125         vcpu->arch.update_pte.pfn = bad_pfn;
2126
2127         if (tdp_enabled)
2128                 return init_kvm_tdp_mmu(vcpu);
2129         else
2130                 return init_kvm_softmmu(vcpu);
2131 }
2132
2133 static void destroy_kvm_mmu(struct kvm_vcpu *vcpu)
2134 {
2135         ASSERT(vcpu);
2136         if (VALID_PAGE(vcpu->arch.mmu.root_hpa)) {
2137                 vcpu->arch.mmu.free(vcpu);
2138                 vcpu->arch.mmu.root_hpa = INVALID_PAGE;
2139         }
2140 }
2141
2142 int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
2143 {
2144         destroy_kvm_mmu(vcpu);
2145         return init_kvm_mmu(vcpu);
2146 }
2147 EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
2148
2149 int kvm_mmu_load(struct kvm_vcpu *vcpu)
2150 {
2151         int r;
2152
2153         r = mmu_topup_memory_caches(vcpu);
2154         if (r)
2155                 goto out;
2156         spin_lock(&vcpu->kvm->mmu_lock);
2157         kvm_mmu_free_some_pages(vcpu);
2158         mmu_alloc_roots(vcpu);
2159         mmu_sync_roots(vcpu);
2160         spin_unlock(&vcpu->kvm->mmu_lock);
2161         kvm_x86_ops->set_cr3(vcpu, vcpu->arch.mmu.root_hpa);
2162         kvm_mmu_flush_tlb(vcpu);
2163 out:
2164         return r;
2165 }
2166 EXPORT_SYMBOL_GPL(kvm_mmu_load);
2167
2168 void kvm_mmu_unload(struct kvm_vcpu *vcpu)
2169 {
2170         mmu_free_roots(vcpu);
2171 }
2172
2173 static void mmu_pte_write_zap_pte(struct kvm_vcpu *vcpu,
2174                                   struct kvm_mmu_page *sp,
2175                                   u64 *spte)
2176 {
2177         u64 pte;
2178         struct kvm_mmu_page *child;
2179
2180         pte = *spte;
2181         if (is_shadow_present_pte(pte)) {
2182                 if (sp->role.level == PT_PAGE_TABLE_LEVEL ||
2183                     is_large_pte(pte))
2184                         rmap_remove(vcpu->kvm, spte);
2185                 else {
2186                         child = page_header(pte & PT64_BASE_ADDR_MASK);
2187                         mmu_page_remove_parent_pte(child, spte);
2188                 }
2189         }
2190         set_shadow_pte(spte, shadow_trap_nonpresent_pte);
2191         if (is_large_pte(pte))
2192                 --vcpu->kvm->stat.lpages;
2193 }
2194
2195 static void mmu_pte_write_new_pte(struct kvm_vcpu *vcpu,
2196                                   struct kvm_mmu_page *sp,
2197                                   u64 *spte,
2198                                   const void *new)
2199 {
2200         if (sp->role.level != PT_PAGE_TABLE_LEVEL) {
2201                 if (!vcpu->arch.update_pte.largepage ||
2202                     sp->role.glevels == PT32_ROOT_LEVEL) {
2203                         ++vcpu->kvm->stat.mmu_pde_zapped;
2204                         return;
2205                 }
2206         }
2207
2208         ++vcpu->kvm->stat.mmu_pte_updated;
2209         if (sp->role.glevels == PT32_ROOT_LEVEL)
2210                 paging32_update_pte(vcpu, sp, spte, new);
2211         else
2212                 paging64_update_pte(vcpu, sp, spte, new);
2213 }
2214
2215 static bool need_remote_flush(u64 old, u64 new)
2216 {
2217         if (!is_shadow_present_pte(old))
2218                 return false;
2219         if (!is_shadow_present_pte(new))
2220                 return true;
2221         if ((old ^ new) & PT64_BASE_ADDR_MASK)
2222                 return true;
2223         old ^= PT64_NX_MASK;
2224         new ^= PT64_NX_MASK;
2225         return (old & ~new & PT64_PERM_MASK) != 0;
2226 }
2227
2228 static void mmu_pte_write_flush_tlb(struct kvm_vcpu *vcpu, u64 old, u64 new)
2229 {
2230         if (need_remote_flush(old, new))
2231                 kvm_flush_remote_tlbs(vcpu->kvm);
2232         else
2233                 kvm_mmu_flush_tlb(vcpu);
2234 }
2235
2236 static bool last_updated_pte_accessed(struct kvm_vcpu *vcpu)
2237 {
2238         u64 *spte = vcpu->arch.last_pte_updated;
2239
2240         return !!(spte && (*spte & shadow_accessed_mask));
2241 }
2242
2243 static void mmu_guess_page_from_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
2244                                           const u8 *new, int bytes)
2245 {
2246         gfn_t gfn;
2247         int r;
2248         u64 gpte = 0;
2249         pfn_t pfn;
2250
2251         vcpu->arch.update_pte.largepage = 0;
2252
2253         if (bytes != 4 && bytes != 8)
2254                 return;
2255
2256         /*
2257          * Assume that the pte write on a page table of the same type
2258          * as the current vcpu paging mode.  This is nearly always true
2259          * (might be false while changing modes).  Note it is verified later
2260          * by update_pte().
2261          */
2262         if (is_pae(vcpu)) {
2263                 /* Handle a 32-bit guest writing two halves of a 64-bit gpte */
2264                 if ((bytes == 4) && (gpa % 4 == 0)) {
2265                         r = kvm_read_guest(vcpu->kvm, gpa & ~(u64)7, &gpte, 8);
2266                         if (r)
2267                                 return;
2268                         memcpy((void *)&gpte + (gpa % 8), new, 4);
2269                 } else if ((bytes == 8) && (gpa % 8 == 0)) {
2270                         memcpy((void *)&gpte, new, 8);
2271                 }
2272         } else {
2273                 if ((bytes == 4) && (gpa % 4 == 0))
2274                         memcpy((void *)&gpte, new, 4);
2275         }
2276         if (!is_present_pte(gpte))
2277                 return;
2278         gfn = (gpte & PT64_BASE_ADDR_MASK) >> PAGE_SHIFT;
2279
2280         if (is_large_pte(gpte) && is_largepage_backed(vcpu, gfn)) {
2281                 gfn &= ~(KVM_PAGES_PER_HPAGE-1);
2282                 vcpu->arch.update_pte.largepage = 1;
2283         }
2284         vcpu->arch.update_pte.mmu_seq = vcpu->kvm->mmu_notifier_seq;
2285         smp_rmb();
2286         pfn = gfn_to_pfn(vcpu->kvm, gfn);
2287
2288         if (is_error_pfn(pfn)) {
2289                 kvm_release_pfn_clean(pfn);
2290                 return;
2291         }
2292         vcpu->arch.update_pte.gfn = gfn;
2293         vcpu->arch.update_pte.pfn = pfn;
2294 }
2295
2296 static void kvm_mmu_access_page(struct kvm_vcpu *vcpu, gfn_t gfn)
2297 {
2298         u64 *spte = vcpu->arch.last_pte_updated;
2299
2300         if (spte
2301             && vcpu->arch.last_pte_gfn == gfn
2302             && shadow_accessed_mask
2303             && !(*spte & shadow_accessed_mask)
2304             && is_shadow_present_pte(*spte))
2305                 set_bit(PT_ACCESSED_SHIFT, (unsigned long *)spte);
2306 }
2307
2308 void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
2309                        const u8 *new, int bytes)
2310 {
2311         gfn_t gfn = gpa >> PAGE_SHIFT;
2312         struct kvm_mmu_page *sp;
2313         struct hlist_node *node, *n;
2314         struct hlist_head *bucket;
2315         unsigned index;
2316         u64 entry, gentry;
2317         u64 *spte;
2318         unsigned offset = offset_in_page(gpa);
2319         unsigned pte_size;
2320         unsigned page_offset;
2321         unsigned misaligned;
2322         unsigned quadrant;
2323         int level;
2324         int flooded = 0;
2325         int npte;
2326         int r;
2327
2328         pgprintk("%s: gpa %llx bytes %d\n", __func__, gpa, bytes);
2329         mmu_guess_page_from_pte_write(vcpu, gpa, new, bytes);
2330         spin_lock(&vcpu->kvm->mmu_lock);
2331         kvm_mmu_access_page(vcpu, gfn);
2332         kvm_mmu_free_some_pages(vcpu);
2333         ++vcpu->kvm->stat.mmu_pte_write;
2334         kvm_mmu_audit(vcpu, "pre pte write");
2335         if (gfn == vcpu->arch.last_pt_write_gfn
2336             && !last_updated_pte_accessed(vcpu)) {
2337                 ++vcpu->arch.last_pt_write_count;
2338                 if (vcpu->arch.last_pt_write_count >= 3)
2339                         flooded = 1;
2340         } else {
2341                 vcpu->arch.last_pt_write_gfn = gfn;
2342                 vcpu->arch.last_pt_write_count = 1;
2343                 vcpu->arch.last_pte_updated = NULL;
2344         }
2345         index = kvm_page_table_hashfn(gfn);
2346         bucket = &vcpu->kvm->arch.mmu_page_hash[index];
2347         hlist_for_each_entry_safe(sp, node, n, bucket, hash_link) {
2348                 if (sp->gfn != gfn || sp->role.metaphysical || sp->role.invalid)
2349                         continue;
2350                 pte_size = sp->role.glevels == PT32_ROOT_LEVEL ? 4 : 8;
2351                 misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);
2352                 misaligned |= bytes < 4;
2353                 if (misaligned || flooded) {
2354                         /*
2355                          * Misaligned accesses are too much trouble to fix
2356                          * up; also, they usually indicate a page is not used
2357                          * as a page table.
2358                          *
2359                          * If we're seeing too many writes to a page,
2360                          * it may no longer be a page table, or we may be
2361                          * forking, in which case it is better to unmap the
2362                          * page.
2363                          */
2364                         pgprintk("misaligned: gpa %llx bytes %d role %x\n",
2365                                  gpa, bytes, sp->role.word);
2366                         if (kvm_mmu_zap_page(vcpu->kvm, sp))
2367                                 n = bucket->first;
2368                         ++vcpu->kvm->stat.mmu_flooded;
2369                         continue;
2370                 }
2371                 page_offset = offset;
2372                 level = sp->role.level;
2373                 npte = 1;
2374                 if (sp->role.glevels == PT32_ROOT_LEVEL) {
2375                         page_offset <<= 1;      /* 32->64 */
2376                         /*
2377                          * A 32-bit pde maps 4MB while the shadow pdes map
2378                          * only 2MB.  So we need to double the offset again
2379                          * and zap two pdes instead of one.
2380                          */
2381                         if (level == PT32_ROOT_LEVEL) {
2382                                 page_offset &= ~7; /* kill rounding error */
2383                                 page_offset <<= 1;
2384                                 npte = 2;
2385                         }
2386                         quadrant = page_offset >> PAGE_SHIFT;
2387                         page_offset &= ~PAGE_MASK;
2388                         if (quadrant != sp->role.quadrant)
2389                                 continue;
2390                 }
2391                 spte = &sp->spt[page_offset / sizeof(*spte)];
2392                 if ((gpa & (pte_size - 1)) || (bytes < pte_size)) {
2393                         gentry = 0;
2394                         r = kvm_read_guest_atomic(vcpu->kvm,
2395                                                   gpa & ~(u64)(pte_size - 1),
2396                                                   &gentry, pte_size);
2397                         new = (const void *)&gentry;
2398                         if (r < 0)
2399                                 new = NULL;
2400                 }
2401                 while (npte--) {
2402                         entry = *spte;
2403                         mmu_pte_write_zap_pte(vcpu, sp, spte);
2404                         if (new)
2405                                 mmu_pte_write_new_pte(vcpu, sp, spte, new);
2406                         mmu_pte_write_flush_tlb(vcpu, entry, *spte);
2407                         ++spte;
2408                 }
2409         }
2410         kvm_mmu_audit(vcpu, "post pte write");
2411         spin_unlock(&vcpu->kvm->mmu_lock);
2412         if (!is_error_pfn(vcpu->arch.update_pte.pfn)) {
2413                 kvm_release_pfn_clean(vcpu->arch.update_pte.pfn);
2414                 vcpu->arch.update_pte.pfn = bad_pfn;
2415         }
2416 }
2417
2418 int kvm_mmu_unprotect_page_virt(struct kvm_vcpu *vcpu, gva_t gva)
2419 {
2420         gpa_t gpa;
2421         int r;
2422
2423         gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, gva);
2424
2425         spin_lock(&vcpu->kvm->mmu_lock);
2426         r = kvm_mmu_unprotect_page(vcpu->kvm, gpa >> PAGE_SHIFT);
2427         spin_unlock(&vcpu->kvm->mmu_lock);
2428         return r;
2429 }
2430 EXPORT_SYMBOL_GPL(kvm_mmu_unprotect_page_virt);
2431
2432 void __kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
2433 {
2434         while (vcpu->kvm->arch.n_free_mmu_pages < KVM_REFILL_PAGES) {
2435                 struct kvm_mmu_page *sp;
2436
2437                 sp = container_of(vcpu->kvm->arch.active_mmu_pages.prev,
2438                                   struct kvm_mmu_page, link);
2439                 kvm_mmu_zap_page(vcpu->kvm, sp);
2440                 ++vcpu->kvm->stat.mmu_recycled;
2441         }
2442 }
2443
2444 int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code)
2445 {
2446         int r;
2447         enum emulation_result er;
2448
2449         r = vcpu->arch.mmu.page_fault(vcpu, cr2, error_code);
2450         if (r < 0)
2451                 goto out;
2452
2453         if (!r) {
2454                 r = 1;
2455                 goto out;
2456         }
2457
2458         r = mmu_topup_memory_caches(vcpu);
2459         if (r)
2460                 goto out;
2461
2462         er = emulate_instruction(vcpu, vcpu->run, cr2, error_code, 0);
2463
2464         switch (er) {
2465         case EMULATE_DONE:
2466                 return 1;
2467         case EMULATE_DO_MMIO:
2468                 ++vcpu->stat.mmio_exits;
2469                 return 0;
2470         case EMULATE_FAIL:
2471                 kvm_report_emulation_failure(vcpu, "pagetable");
2472                 return 1;
2473         default:
2474                 BUG();
2475         }
2476 out:
2477         return r;
2478 }
2479 EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);
2480
2481 void kvm_mmu_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
2482 {
2483         spin_lock(&vcpu->kvm->mmu_lock);
2484         vcpu->arch.mmu.invlpg(vcpu, gva);
2485         spin_unlock(&vcpu->kvm->mmu_lock);
2486         kvm_mmu_flush_tlb(vcpu);
2487         ++vcpu->stat.invlpg;
2488 }
2489 EXPORT_SYMBOL_GPL(kvm_mmu_invlpg);
2490
2491 void kvm_enable_tdp(void)
2492 {
2493         tdp_enabled = true;
2494 }
2495 EXPORT_SYMBOL_GPL(kvm_enable_tdp);
2496
2497 void kvm_disable_tdp(void)
2498 {
2499         tdp_enabled = false;
2500 }
2501 EXPORT_SYMBOL_GPL(kvm_disable_tdp);
2502
2503 static void free_mmu_pages(struct kvm_vcpu *vcpu)
2504 {
2505         struct kvm_mmu_page *sp;
2506
2507         while (!list_empty(&vcpu->kvm->arch.active_mmu_pages)) {
2508                 sp = container_of(vcpu->kvm->arch.active_mmu_pages.next,
2509                                   struct kvm_mmu_page, link);
2510                 kvm_mmu_zap_page(vcpu->kvm, sp);
2511                 cond_resched();
2512         }
2513         free_page((unsigned long)vcpu->arch.mmu.pae_root);
2514 }
2515
2516 static int alloc_mmu_pages(struct kvm_vcpu *vcpu)
2517 {
2518         struct page *page;
2519         int i;
2520
2521         ASSERT(vcpu);
2522
2523         if (vcpu->kvm->arch.n_requested_mmu_pages)
2524                 vcpu->kvm->arch.n_free_mmu_pages =
2525                                         vcpu->kvm->arch.n_requested_mmu_pages;
2526         else
2527                 vcpu->kvm->arch.n_free_mmu_pages =
2528                                         vcpu->kvm->arch.n_alloc_mmu_pages;
2529         /*
2530          * When emulating 32-bit mode, cr3 is only 32 bits even on x86_64.
2531          * Therefore we need to allocate shadow page tables in the first
2532          * 4GB of memory, which happens to fit the DMA32 zone.
2533          */
2534         page = alloc_page(GFP_KERNEL | __GFP_DMA32);
2535         if (!page)
2536                 goto error_1;
2537         vcpu->arch.mmu.pae_root = page_address(page);
2538         for (i = 0; i < 4; ++i)
2539                 vcpu->arch.mmu.pae_root[i] = INVALID_PAGE;
2540
2541         return 0;
2542
2543 error_1:
2544         free_mmu_pages(vcpu);
2545         return -ENOMEM;
2546 }
2547
2548 int kvm_mmu_create(struct kvm_vcpu *vcpu)
2549 {
2550         ASSERT(vcpu);
2551         ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
2552
2553         return alloc_mmu_pages(vcpu);
2554 }
2555
2556 int kvm_mmu_setup(struct kvm_vcpu *vcpu)
2557 {
2558         ASSERT(vcpu);
2559         ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
2560
2561         return init_kvm_mmu(vcpu);
2562 }
2563
2564 void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
2565 {
2566         ASSERT(vcpu);
2567
2568         destroy_kvm_mmu(vcpu);
2569         free_mmu_pages(vcpu);
2570         mmu_free_memory_caches(vcpu);
2571 }
2572
2573 void kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot)
2574 {
2575         struct kvm_mmu_page *sp;
2576
2577         spin_lock(&kvm->mmu_lock);
2578         list_for_each_entry(sp, &kvm->arch.active_mmu_pages, link) {
2579                 int i;
2580                 u64 *pt;
2581
2582                 if (!test_bit(slot, sp->slot_bitmap))
2583                         continue;
2584
2585                 pt = sp->spt;
2586                 for (i = 0; i < PT64_ENT_PER_PAGE; ++i)
2587                         /* avoid RMW */
2588                         if (pt[i] & PT_WRITABLE_MASK)
2589                                 pt[i] &= ~PT_WRITABLE_MASK;
2590         }
2591         kvm_flush_remote_tlbs(kvm);
2592         spin_unlock(&kvm->mmu_lock);
2593 }
2594
2595 void kvm_mmu_zap_all(struct kvm *kvm)
2596 {
2597         struct kvm_mmu_page *sp, *node;
2598
2599         spin_lock(&kvm->mmu_lock);
2600         list_for_each_entry_safe(sp, node, &kvm->arch.active_mmu_pages, link)
2601                 if (kvm_mmu_zap_page(kvm, sp))
2602                         node = container_of(kvm->arch.active_mmu_pages.next,
2603                                             struct kvm_mmu_page, link);
2604         spin_unlock(&kvm->mmu_lock);
2605
2606         kvm_flush_remote_tlbs(kvm);
2607 }
2608
2609 static void kvm_mmu_remove_one_alloc_mmu_page(struct kvm *kvm)
2610 {
2611         struct kvm_mmu_page *page;
2612
2613         page = container_of(kvm->arch.active_mmu_pages.prev,
2614                             struct kvm_mmu_page, link);
2615         kvm_mmu_zap_page(kvm, page);
2616 }
2617
2618 static int mmu_shrink(int nr_to_scan, gfp_t gfp_mask)
2619 {
2620         struct kvm *kvm;
2621         struct kvm *kvm_freed = NULL;
2622         int cache_count = 0;
2623
2624         spin_lock(&kvm_lock);
2625
2626         list_for_each_entry(kvm, &vm_list, vm_list) {
2627                 int npages;
2628
2629                 if (!down_read_trylock(&kvm->slots_lock))
2630                         continue;
2631                 spin_lock(&kvm->mmu_lock);
2632                 npages = kvm->arch.n_alloc_mmu_pages -
2633                          kvm->arch.n_free_mmu_pages;
2634                 cache_count += npages;
2635                 if (!kvm_freed && nr_to_scan > 0 && npages > 0) {
2636                         kvm_mmu_remove_one_alloc_mmu_page(kvm);
2637                         cache_count--;
2638                         kvm_freed = kvm;
2639                 }
2640                 nr_to_scan--;
2641
2642                 spin_unlock(&kvm->mmu_lock);
2643                 up_read(&kvm->slots_lock);
2644         }
2645         if (kvm_freed)
2646                 list_move_tail(&kvm_freed->vm_list, &vm_list);
2647
2648         spin_unlock(&kvm_lock);
2649
2650         return cache_count;
2651 }
2652
2653 static struct shrinker mmu_shrinker = {
2654         .shrink = mmu_shrink,
2655         .seeks = DEFAULT_SEEKS * 10,
2656 };
2657
2658 static void mmu_destroy_caches(void)
2659 {
2660         if (pte_chain_cache)
2661                 kmem_cache_destroy(pte_chain_cache);
2662         if (rmap_desc_cache)
2663                 kmem_cache_destroy(rmap_desc_cache);
2664         if (mmu_page_header_cache)
2665                 kmem_cache_destroy(mmu_page_header_cache);
2666 }
2667
2668 void kvm_mmu_module_exit(void)
2669 {
2670         mmu_destroy_caches();
2671         unregister_shrinker(&mmu_shrinker);
2672 }
2673
2674 int kvm_mmu_module_init(void)
2675 {
2676         pte_chain_cache = kmem_cache_create("kvm_pte_chain",
2677                                             sizeof(struct kvm_pte_chain),
2678                                             0, 0, NULL);
2679         if (!pte_chain_cache)
2680                 goto nomem;
2681         rmap_desc_cache = kmem_cache_create("kvm_rmap_desc",
2682                                             sizeof(struct kvm_rmap_desc),
2683                                             0, 0, NULL);
2684         if (!rmap_desc_cache)
2685                 goto nomem;
2686
2687         mmu_page_header_cache = kmem_cache_create("kvm_mmu_page_header",
2688                                                   sizeof(struct kvm_mmu_page),
2689                                                   0, 0, NULL);
2690         if (!mmu_page_header_cache)
2691                 goto nomem;
2692
2693         register_shrinker(&mmu_shrinker);
2694
2695         return 0;
2696
2697 nomem:
2698         mmu_destroy_caches();
2699         return -ENOMEM;
2700 }
2701
2702 /*
2703  * Caculate mmu pages needed for kvm.
2704  */
2705 unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
2706 {
2707         int i;
2708         unsigned int nr_mmu_pages;
2709         unsigned int  nr_pages = 0;
2710
2711         for (i = 0; i < kvm->nmemslots; i++)
2712                 nr_pages += kvm->memslots[i].npages;
2713
2714         nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000;
2715         nr_mmu_pages = max(nr_mmu_pages,
2716                         (unsigned int) KVM_MIN_ALLOC_MMU_PAGES);
2717
2718         return nr_mmu_pages;
2719 }
2720
2721 static void *pv_mmu_peek_buffer(struct kvm_pv_mmu_op_buffer *buffer,
2722                                 unsigned len)
2723 {
2724         if (len > buffer->len)
2725                 return NULL;
2726         return buffer->ptr;
2727 }
2728
2729 static void *pv_mmu_read_buffer(struct kvm_pv_mmu_op_buffer *buffer,
2730                                 unsigned len)
2731 {
2732         void *ret;
2733
2734         ret = pv_mmu_peek_buffer(buffer, len);
2735         if (!ret)
2736                 return ret;
2737         buffer->ptr += len;
2738         buffer->len -= len;
2739         buffer->processed += len;
2740         return ret;
2741 }
2742
2743 static int kvm_pv_mmu_write(struct kvm_vcpu *vcpu,
2744                              gpa_t addr, gpa_t value)
2745 {
2746         int bytes = 8;
2747         int r;
2748
2749         if (!is_long_mode(vcpu) && !is_pae(vcpu))
2750                 bytes = 4;
2751
2752         r = mmu_topup_memory_caches(vcpu);
2753         if (r)
2754                 return r;
2755
2756         if (!emulator_write_phys(vcpu, addr, &value, bytes))
2757                 return -EFAULT;
2758
2759         return 1;
2760 }
2761
2762 static int kvm_pv_mmu_flush_tlb(struct kvm_vcpu *vcpu)
2763 {
2764         kvm_x86_ops->tlb_flush(vcpu);
2765         set_bit(KVM_REQ_MMU_SYNC, &vcpu->requests);
2766         return 1;
2767 }
2768
2769 static int kvm_pv_mmu_release_pt(struct kvm_vcpu *vcpu, gpa_t addr)
2770 {
2771         spin_lock(&vcpu->kvm->mmu_lock);
2772         mmu_unshadow(vcpu->kvm, addr >> PAGE_SHIFT);
2773         spin_unlock(&vcpu->kvm->mmu_lock);
2774         return 1;
2775 }
2776
2777 static int kvm_pv_mmu_op_one(struct kvm_vcpu *vcpu,
2778                              struct kvm_pv_mmu_op_buffer *buffer)
2779 {
2780         struct kvm_mmu_op_header *header;
2781
2782         header = pv_mmu_peek_buffer(buffer, sizeof *header);
2783         if (!header)
2784                 return 0;
2785         switch (header->op) {
2786         case KVM_MMU_OP_WRITE_PTE: {
2787                 struct kvm_mmu_op_write_pte *wpte;
2788
2789                 wpte = pv_mmu_read_buffer(buffer, sizeof *wpte);
2790                 if (!wpte)
2791                         return 0;
2792                 return kvm_pv_mmu_write(vcpu, wpte->pte_phys,
2793                                         wpte->pte_val);
2794         }
2795         case KVM_MMU_OP_FLUSH_TLB: {
2796                 struct kvm_mmu_op_flush_tlb *ftlb;
2797
2798                 ftlb = pv_mmu_read_buffer(buffer, sizeof *ftlb);
2799                 if (!ftlb)
2800                         return 0;
2801                 return kvm_pv_mmu_flush_tlb(vcpu);
2802         }
2803         case KVM_MMU_OP_RELEASE_PT: {
2804                 struct kvm_mmu_op_release_pt *rpt;
2805
2806                 rpt = pv_mmu_read_buffer(buffer, sizeof *rpt);
2807                 if (!rpt)
2808                         return 0;
2809                 return kvm_pv_mmu_release_pt(vcpu, rpt->pt_phys);
2810         }
2811         default: return 0;
2812         }
2813 }
2814
2815 int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes,
2816                   gpa_t addr, unsigned long *ret)
2817 {
2818         int r;
2819         struct kvm_pv_mmu_op_buffer *buffer = &vcpu->arch.mmu_op_buffer;
2820
2821         buffer->ptr = buffer->buf;
2822         buffer->len = min_t(unsigned long, bytes, sizeof buffer->buf);
2823         buffer->processed = 0;
2824
2825         r = kvm_read_guest(vcpu->kvm, addr, buffer->buf, buffer->len);
2826         if (r)
2827                 goto out;
2828
2829         while (buffer->len) {
2830                 r = kvm_pv_mmu_op_one(vcpu, buffer);
2831                 if (r < 0)
2832                         goto out;
2833                 if (r == 0)
2834                         break;
2835         }
2836
2837         r = 1;
2838 out:
2839         *ret = buffer->processed;
2840         return r;
2841 }
2842
2843 #ifdef AUDIT
2844
2845 static const char *audit_msg;
2846
2847 static gva_t canonicalize(gva_t gva)
2848 {
2849 #ifdef CONFIG_X86_64
2850         gva = (long long)(gva << 16) >> 16;
2851 #endif
2852         return gva;
2853 }
2854
2855 static void audit_mappings_page(struct kvm_vcpu *vcpu, u64 page_pte,
2856                                 gva_t va, int level)
2857 {
2858         u64 *pt = __va(page_pte & PT64_BASE_ADDR_MASK);
2859         int i;
2860         gva_t va_delta = 1ul << (PAGE_SHIFT + 9 * (level - 1));
2861
2862         for (i = 0; i < PT64_ENT_PER_PAGE; ++i, va += va_delta) {
2863                 u64 ent = pt[i];
2864
2865                 if (ent == shadow_trap_nonpresent_pte)
2866                         continue;
2867
2868                 va = canonicalize(va);
2869                 if (level > 1) {
2870                         if (ent == shadow_notrap_nonpresent_pte)
2871                                 printk(KERN_ERR "audit: (%s) nontrapping pte"
2872                                        " in nonleaf level: levels %d gva %lx"
2873                                        " level %d pte %llx\n", audit_msg,
2874                                        vcpu->arch.mmu.root_level, va, level, ent);
2875
2876                         audit_mappings_page(vcpu, ent, va, level - 1);
2877                 } else {
2878                         gpa_t gpa = vcpu->arch.mmu.gva_to_gpa(vcpu, va);
2879                         hpa_t hpa = (hpa_t)gpa_to_pfn(vcpu, gpa) << PAGE_SHIFT;
2880
2881                         if (is_shadow_present_pte(ent)
2882                             && (ent & PT64_BASE_ADDR_MASK) != hpa)
2883                                 printk(KERN_ERR "xx audit error: (%s) levels %d"
2884                                        " gva %lx gpa %llx hpa %llx ent %llx %d\n",
2885                                        audit_msg, vcpu->arch.mmu.root_level,
2886                                        va, gpa, hpa, ent,
2887                                        is_shadow_present_pte(ent));
2888                         else if (ent == shadow_notrap_nonpresent_pte
2889                                  && !is_error_hpa(hpa))
2890                                 printk(KERN_ERR "audit: (%s) notrap shadow,"
2891                                        " valid guest gva %lx\n", audit_msg, va);
2892                         kvm_release_pfn_clean(pfn);
2893
2894                 }
2895         }
2896 }
2897
2898 static void audit_mappings(struct kvm_vcpu *vcpu)
2899 {
2900         unsigned i;
2901
2902         if (vcpu->arch.mmu.root_level == 4)
2903                 audit_mappings_page(vcpu, vcpu->arch.mmu.root_hpa, 0, 4);
2904         else
2905                 for (i = 0; i < 4; ++i)
2906                         if (vcpu->arch.mmu.pae_root[i] & PT_PRESENT_MASK)
2907                                 audit_mappings_page(vcpu,
2908                                                     vcpu->arch.mmu.pae_root[i],
2909                                                     i << 30,
2910                                                     2);
2911 }
2912
2913 static int count_rmaps(struct kvm_vcpu *vcpu)
2914 {
2915         int nmaps = 0;
2916         int i, j, k;
2917
2918         for (i = 0; i < KVM_MEMORY_SLOTS; ++i) {
2919                 struct kvm_memory_slot *m = &vcpu->kvm->memslots[i];
2920                 struct kvm_rmap_desc *d;
2921
2922                 for (j = 0; j < m->npages; ++j) {
2923                         unsigned long *rmapp = &m->rmap[j];
2924
2925                         if (!*rmapp)
2926                                 continue;
2927                         if (!(*rmapp & 1)) {
2928                                 ++nmaps;
2929                                 continue;
2930                         }
2931                         d = (struct kvm_rmap_desc *)(*rmapp & ~1ul);
2932                         while (d) {
2933                                 for (k = 0; k < RMAP_EXT; ++k)
2934                                         if (d->shadow_ptes[k])
2935                                                 ++nmaps;
2936                                         else
2937                                                 break;
2938                                 d = d->more;
2939                         }
2940                 }
2941         }
2942         return nmaps;
2943 }
2944
2945 static int count_writable_mappings(struct kvm_vcpu *vcpu)
2946 {
2947         int nmaps = 0;
2948         struct kvm_mmu_page *sp;
2949         int i;
2950
2951         list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
2952                 u64 *pt = sp->spt;
2953
2954                 if (sp->role.level != PT_PAGE_TABLE_LEVEL)
2955                         continue;
2956
2957                 for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
2958                         u64 ent = pt[i];
2959
2960                         if (!(ent & PT_PRESENT_MASK))
2961                                 continue;
2962                         if (!(ent & PT_WRITABLE_MASK))
2963                                 continue;
2964                         ++nmaps;
2965                 }
2966         }
2967         return nmaps;
2968 }
2969
2970 static void audit_rmap(struct kvm_vcpu *vcpu)
2971 {
2972         int n_rmap = count_rmaps(vcpu);
2973         int n_actual = count_writable_mappings(vcpu);
2974
2975         if (n_rmap != n_actual)
2976                 printk(KERN_ERR "%s: (%s) rmap %d actual %d\n",
2977                        __func__, audit_msg, n_rmap, n_actual);
2978 }
2979
2980 static void audit_write_protection(struct kvm_vcpu *vcpu)
2981 {
2982         struct kvm_mmu_page *sp;
2983         struct kvm_memory_slot *slot;
2984         unsigned long *rmapp;
2985         gfn_t gfn;
2986
2987         list_for_each_entry(sp, &vcpu->kvm->arch.active_mmu_pages, link) {
2988                 if (sp->role.metaphysical)
2989                         continue;
2990
2991                 gfn = unalias_gfn(vcpu->kvm, sp->gfn);
2992                 slot = gfn_to_memslot_unaliased(vcpu->kvm, sp->gfn);
2993                 rmapp = &slot->rmap[gfn - slot->base_gfn];
2994                 if (*rmapp)
2995                         printk(KERN_ERR "%s: (%s) shadow page has writable"
2996                                " mappings: gfn %lx role %x\n",
2997                                __func__, audit_msg, sp->gfn,
2998                                sp->role.word);
2999         }
3000 }
3001
3002 static void kvm_mmu_audit(struct kvm_vcpu *vcpu, const char *msg)
3003 {
3004         int olddbg = dbg;
3005
3006         dbg = 0;
3007         audit_msg = msg;
3008         audit_rmap(vcpu);
3009         audit_write_protection(vcpu);
3010         audit_mappings(vcpu);
3011         dbg = olddbg;
3012 }
3013
3014 #endif