arch/mips/kvm/mmu.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * KVM/MIPS MMU handling in the KVM module.
   7  *
   8  * Copyright (C) 2012  MIPS Technologies, Inc.  All rights reserved.
   9  * Authors: Sanjay Lal <sanjayl@kymasys.com>
  10  */
  11
  12 #include <linux/highmem.h>
  13 #include <linux/kvm_host.h>
  14 #include <linux/uaccess.h>
  15 #include <asm/mmu_context.h>
  16 #include <asm/pgalloc.h>
  17
  18 /*
  19  * KVM_MMU_CACHE_MIN_PAGES is the number of GPA page table translation levels
  20  * for which pages need to be cached.
  21  */
  22 #if defined(__PAGETABLE_PMD_FOLDED)
  23 #define KVM_MMU_CACHE_MIN_PAGES 1
  24 #else
  25 #define KVM_MMU_CACHE_MIN_PAGES 2
  26 #endif
  27
  28 static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
  29                                   int min, int max)
  30 {
  31         void *page;
  32
  33         BUG_ON(max > KVM_NR_MEM_OBJS);
  34         if (cache->nobjs >= min)
  35                 return 0;
  36         while (cache->nobjs < max) {
  37                 page = (void *)__get_free_page(GFP_KERNEL);
  38                 if (!page)
  39                         return -ENOMEM;
  40                 cache->objects[cache->nobjs++] = page;
  41         }
  42         return 0;
  43 }
  44
  45 static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
  46 {
  47         while (mc->nobjs)
  48                 free_page((unsigned long)mc->objects[--mc->nobjs]);
  49 }
  50
  51 static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
  52 {
  53         void *p;
  54
  55         BUG_ON(!mc || !mc->nobjs);
  56         p = mc->objects[--mc->nobjs];
  57         return p;
  58 }
  59
  60 void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu)
  61 {
  62         mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
  63 }
  64
  65 /**
  66  * kvm_pgd_init() - Initialise KVM GPA page directory.
  67  * @page:       Pointer to page directory (PGD) for KVM GPA.
  68  *
  69  * Initialise a KVM GPA page directory with pointers to the invalid table, i.e.
  70  * representing no mappings. This is similar to pgd_init(), however it
  71  * initialises all the page directory pointers, not just the ones corresponding
  72  * to the userland address space (since it is for the guest physical address
  73  * space rather than a virtual address space).
  74  */
  75 static void kvm_pgd_init(void *page)
  76 {
  77         unsigned long *p, *end;
  78         unsigned long entry;
  79
  80 #ifdef __PAGETABLE_PMD_FOLDED
  81         entry = (unsigned long)invalid_pte_table;
  82 #else
  83         entry = (unsigned long)invalid_pmd_table;
  84 #endif
  85
  86         p = (unsigned long *)page;
  87         end = p + PTRS_PER_PGD;
  88
  89         do {
  90                 p[0] = entry;
  91                 p[1] = entry;
  92                 p[2] = entry;
  93                 p[3] = entry;
  94                 p[4] = entry;
  95                 p += 8;
  96                 p[-3] = entry;
  97                 p[-2] = entry;
  98                 p[-1] = entry;
  99         } while (p != end);
 100 }
 101
 102 /**
 103  * kvm_pgd_alloc() - Allocate and initialise a KVM GPA page directory.
 104  *
 105  * Allocate a blank KVM GPA page directory (PGD) for representing guest physical
 106  * to host physical page mappings.
 107  *
 108  * Returns:     Pointer to new KVM GPA page directory.
 109  *              NULL on allocation failure.
 110  */
 111 pgd_t *kvm_pgd_alloc(void)
 112 {
 113         pgd_t *ret;
 114
 115         ret = (pgd_t *)__get_free_pages(GFP_KERNEL, PGD_ORDER);
 116         if (ret)
 117                 kvm_pgd_init(ret);
 118
 119         return ret;
 120 }
 121
 122 /**
 123  * kvm_mips_walk_pgd() - Walk page table with optional allocation.
 124  * @pgd:        Page directory pointer.
 125  * @addr:       Address to index page table using.
 126  * @cache:      MMU page cache to allocate new page tables from, or NULL.
 127  *
 128  * Walk the page tables pointed to by @pgd to find the PTE corresponding to the
 129  * address @addr. If page tables don't exist for @addr, they will be created
 130  * from the MMU cache if @cache is not NULL.
 131  *
 132  * Returns:     Pointer to pte_t corresponding to @addr.
 133  *              NULL if a page table doesn't exist for @addr and !@cache.
 134  *              NULL if a page table allocation failed.
 135  */
 136 static pte_t *kvm_mips_walk_pgd(pgd_t *pgd, struct kvm_mmu_memory_cache *cache,
 137                                 unsigned long addr)
 138 {
 139         pud_t *pud;
 140         pmd_t *pmd;
 141
 142         pgd += pgd_index(addr);
 143         if (pgd_none(*pgd)) {
 144                 /* Not used on MIPS yet */
 145                 BUG();
 146                 return NULL;
 147         }
 148         pud = pud_offset(pgd, addr);
 149         if (pud_none(*pud)) {
 150                 pmd_t *new_pmd;
 151
 152                 if (!cache)
 153                         return NULL;
 154                 new_pmd = mmu_memory_cache_alloc(cache);
 155                 pmd_init((unsigned long)new_pmd,
 156                          (unsigned long)invalid_pte_table);
 157                 pud_populate(NULL, pud, new_pmd);
 158         }
 159         pmd = pmd_offset(pud, addr);
 160         if (pmd_none(*pmd)) {
 161                 pte_t *new_pte;
 162
 163                 if (!cache)
 164                         return NULL;
 165                 new_pte = mmu_memory_cache_alloc(cache);
 166                 clear_page(new_pte);
 167                 pmd_populate_kernel(NULL, pmd, new_pte);
 168         }
 169         return pte_offset(pmd, addr);
 170 }
 171
 172 /* Caller must hold kvm->mm_lock */
 173 static pte_t *kvm_mips_pte_for_gpa(struct kvm *kvm,
 174                                    struct kvm_mmu_memory_cache *cache,
 175                                    unsigned long addr)
 176 {
 177         return kvm_mips_walk_pgd(kvm->arch.gpa_mm.pgd, cache, addr);
 178 }
 179
 180 /*
 181  * kvm_mips_flush_gpa_{pte,pmd,pud,pgd,pt}.
 182  * Flush a range of guest physical address space from the VM's GPA page tables.
 183  */
 184
 185 static bool kvm_mips_flush_gpa_pte(pte_t *pte, unsigned long start_gpa,
 186                                    unsigned long end_gpa)
 187 {
 188         int i_min = __pte_offset(start_gpa);
 189         int i_max = __pte_offset(end_gpa);
 190         bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PTE - 1);
 191         int i;
 192
 193         for (i = i_min; i <= i_max; ++i) {
 194                 if (!pte_present(pte[i]))
 195                         continue;
 196
 197                 set_pte(pte + i, __pte(0));
 198         }
 199         return safe_to_remove;
 200 }
 201
 202 static bool kvm_mips_flush_gpa_pmd(pmd_t *pmd, unsigned long start_gpa,
 203                                    unsigned long end_gpa)
 204 {
 205         pte_t *pte;
 206         unsigned long end = ~0ul;
 207         int i_min = __pmd_offset(start_gpa);
 208         int i_max = __pmd_offset(end_gpa);
 209         bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PMD - 1);
 210         int i;
 211
 212         for (i = i_min; i <= i_max; ++i, start_gpa = 0) {
 213                 if (!pmd_present(pmd[i]))
 214                         continue;
 215
 216                 pte = pte_offset(pmd + i, 0);
 217                 if (i == i_max)
 218                         end = end_gpa;
 219
 220                 if (kvm_mips_flush_gpa_pte(pte, start_gpa, end)) {
 221                         pmd_clear(pmd + i);
 222                         pte_free_kernel(NULL, pte);
 223                 } else {
 224                         safe_to_remove = false;
 225                 }
 226         }
 227         return safe_to_remove;
 228 }
 229
 230 static bool kvm_mips_flush_gpa_pud(pud_t *pud, unsigned long start_gpa,
 231                                    unsigned long end_gpa)
 232 {
 233         pmd_t *pmd;
 234         unsigned long end = ~0ul;
 235         int i_min = __pud_offset(start_gpa);
 236         int i_max = __pud_offset(end_gpa);
 237         bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PUD - 1);
 238         int i;
 239
 240         for (i = i_min; i <= i_max; ++i, start_gpa = 0) {
 241                 if (!pud_present(pud[i]))
 242                         continue;
 243
 244                 pmd = pmd_offset(pud + i, 0);
 245                 if (i == i_max)
 246                         end = end_gpa;
 247
 248                 if (kvm_mips_flush_gpa_pmd(pmd, start_gpa, end)) {
 249                         pud_clear(pud + i);
 250                         pmd_free(NULL, pmd);
 251                 } else {
 252                         safe_to_remove = false;
 253                 }
 254         }
 255         return safe_to_remove;
 256 }
 257
 258 static bool kvm_mips_flush_gpa_pgd(pgd_t *pgd, unsigned long start_gpa,
 259                                    unsigned long end_gpa)
 260 {
 261         pud_t *pud;
 262         unsigned long end = ~0ul;
 263         int i_min = pgd_index(start_gpa);
 264         int i_max = pgd_index(end_gpa);
 265         bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PGD - 1);
 266         int i;
 267
 268         for (i = i_min; i <= i_max; ++i, start_gpa = 0) {
 269                 if (!pgd_present(pgd[i]))
 270                         continue;
 271
 272                 pud = pud_offset(pgd + i, 0);
 273                 if (i == i_max)
 274                         end = end_gpa;
 275
 276                 if (kvm_mips_flush_gpa_pud(pud, start_gpa, end)) {
 277                         pgd_clear(pgd + i);
 278                         pud_free(NULL, pud);
 279                 } else {
 280                         safe_to_remove = false;
 281                 }
 282         }
 283         return safe_to_remove;
 284 }
 285
 286 /**
 287  * kvm_mips_flush_gpa_pt() - Flush a range of guest physical addresses.
 288  * @kvm:        KVM pointer.
 289  * @start_gfn:  Guest frame number of first page in GPA range to flush.
 290  * @end_gfn:    Guest frame number of last page in GPA range to flush.
 291  *
 292  * Flushes a range of GPA mappings from the GPA page tables.
 293  *
 294  * The caller must hold the @kvm->mmu_lock spinlock.
 295  *
 296  * Returns:     Whether its safe to remove the top level page directory because
 297  *              all lower levels have been removed.
 298  */
 299 bool kvm_mips_flush_gpa_pt(struct kvm *kvm, gfn_t start_gfn, gfn_t end_gfn)
 300 {
 301         return kvm_mips_flush_gpa_pgd(kvm->arch.gpa_mm.pgd,
 302                                       start_gfn << PAGE_SHIFT,
 303                                       end_gfn << PAGE_SHIFT);
 304 }
 305
 306 #define BUILD_PTE_RANGE_OP(name, op)                                    \
 307 static int kvm_mips_##name##_pte(pte_t *pte, unsigned long start,       \
 308                                  unsigned long end)                     \
 309 {                                                                       \
 310         int ret = 0;                                                    \
 311         int i_min = __pte_offset(start);                                \
 312         int i_max = __pte_offset(end);                                  \
 313         int i;                                                          \
 314         pte_t old, new;                                                 \
 315                                                                         \
 316         for (i = i_min; i <= i_max; ++i) {                              \
 317                 if (!pte_present(pte[i]))                               \
 318                         continue;                                       \
 319                                                                         \
 320                 old = pte[i];                                           \
 321                 new = op(old);                                          \
 322                 if (pte_val(new) == pte_val(old))                       \
 323                         continue;                                       \
 324                 set_pte(pte + i, new);                                  \
 325                 ret = 1;                                                \
 326         }                                                               \
 327         return ret;                                                     \
 328 }                                                                       \
 329                                                                         \
 330 /* returns true if anything was done */                                 \
 331 static int kvm_mips_##name##_pmd(pmd_t *pmd, unsigned long start,       \
 332                                  unsigned long end)                     \
 333 {                                                                       \
 334         int ret = 0;                                                    \
 335         pte_t *pte;                                                     \
 336         unsigned long cur_end = ~0ul;                                   \
 337         int i_min = __pmd_offset(start);                                \
 338         int i_max = __pmd_offset(end);                                  \
 339         int i;                                                          \
 340                                                                         \
 341         for (i = i_min; i <= i_max; ++i, start = 0) {                   \
 342                 if (!pmd_present(pmd[i]))                               \
 343                         continue;                                       \
 344                                                                         \
 345                 pte = pte_offset(pmd + i, 0);                           \
 346                 if (i == i_max)                                         \
 347                         cur_end = end;                                  \
 348                                                                         \
 349                 ret |= kvm_mips_##name##_pte(pte, start, cur_end);      \
 350         }                                                               \
 351         return ret;                                                     \
 352 }                                                                       \
 353                                                                         \
 354 static int kvm_mips_##name##_pud(pud_t *pud, unsigned long start,       \
 355                                  unsigned long end)                     \
 356 {                                                                       \
 357         int ret = 0;                                                    \
 358         pmd_t *pmd;                                                     \
 359         unsigned long cur_end = ~0ul;                                   \
 360         int i_min = __pud_offset(start);                                \
 361         int i_max = __pud_offset(end);                                  \
 362         int i;                                                          \
 363                                                                         \
 364         for (i = i_min; i <= i_max; ++i, start = 0) {                   \
 365                 if (!pud_present(pud[i]))                               \
 366                         continue;                                       \
 367                                                                         \
 368                 pmd = pmd_offset(pud + i, 0);                           \
 369                 if (i == i_max)                                         \
 370                         cur_end = end;                                  \
 371                                                                         \
 372                 ret |= kvm_mips_##name##_pmd(pmd, start, cur_end);      \
 373         }                                                               \
 374         return ret;                                                     \
 375 }                                                                       \
 376                                                                         \
 377 static int kvm_mips_##name##_pgd(pgd_t *pgd, unsigned long start,       \
 378                                  unsigned long end)                     \
 379 {                                                                       \
 380         int ret = 0;                                                    \
 381         pud_t *pud;                                                     \
 382         unsigned long cur_end = ~0ul;                                   \
 383         int i_min = pgd_index(start);                                   \
 384         int i_max = pgd_index(end);                                     \
 385         int i;                                                          \
 386                                                                         \
 387         for (i = i_min; i <= i_max; ++i, start = 0) {                   \
 388                 if (!pgd_present(pgd[i]))                               \
 389                         continue;                                       \
 390                                                                         \
 391                 pud = pud_offset(pgd + i, 0);                           \
 392                 if (i == i_max)                                         \
 393                         cur_end = end;                                  \
 394                                                                         \
 395                 ret |= kvm_mips_##name##_pud(pud, start, cur_end);      \
 396         }                                                               \
 397         return ret;                                                     \
 398 }
 399
 400 /*
 401  * kvm_mips_mkclean_gpa_pt.
 402  * Mark a range of guest physical address space clean (writes fault) in the VM's
 403  * GPA page table to allow dirty page tracking.
 404  */
 405
 406 BUILD_PTE_RANGE_OP(mkclean, pte_mkclean)
 407
 408 /**
 409  * kvm_mips_mkclean_gpa_pt() - Make a range of guest physical addresses clean.
 410  * @kvm:        KVM pointer.
 411  * @start_gfn:  Guest frame number of first page in GPA range to flush.
 412  * @end_gfn:    Guest frame number of last page in GPA range to flush.
 413  *
 414  * Make a range of GPA mappings clean so that guest writes will fault and
 415  * trigger dirty page logging.
 416  *
 417  * The caller must hold the @kvm->mmu_lock spinlock.
 418  *
 419  * Returns:     Whether any GPA mappings were modified, which would require
 420  *              derived mappings (GVA page tables & TLB enties) to be
 421  *              invalidated.
 422  */
 423 int kvm_mips_mkclean_gpa_pt(struct kvm *kvm, gfn_t start_gfn, gfn_t end_gfn)
 424 {
 425         return kvm_mips_mkclean_pgd(kvm->arch.gpa_mm.pgd,
 426                                     start_gfn << PAGE_SHIFT,
 427                                     end_gfn << PAGE_SHIFT);
 428 }
 429
 430 /**
 431  * kvm_arch_mmu_enable_log_dirty_pt_masked() - write protect dirty pages
 432  * @kvm:        The KVM pointer
 433  * @slot:       The memory slot associated with mask
 434  * @gfn_offset: The gfn offset in memory slot
 435  * @mask:       The mask of dirty pages at offset 'gfn_offset' in this memory
 436  *              slot to be write protected
 437  *
 438  * Walks bits set in mask write protects the associated pte's. Caller must
 439  * acquire @kvm->mmu_lock.
 440  */
 441 void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
 442                 struct kvm_memory_slot *slot,
 443                 gfn_t gfn_offset, unsigned long mask)
 444 {
 445         gfn_t base_gfn = slot->base_gfn + gfn_offset;
 446         gfn_t start = base_gfn +  __ffs(mask);
 447         gfn_t end = base_gfn + __fls(mask);
 448
 449         kvm_mips_mkclean_gpa_pt(kvm, start, end);
 450 }
 451
 452 /*
 453  * kvm_mips_mkold_gpa_pt.
 454  * Mark a range of guest physical address space old (all accesses fault) in the
 455  * VM's GPA page table to allow detection of commonly used pages.
 456  */
 457
 458 BUILD_PTE_RANGE_OP(mkold, pte_mkold)
 459
 460 static int kvm_mips_mkold_gpa_pt(struct kvm *kvm, gfn_t start_gfn,
 461                                  gfn_t end_gfn)
 462 {
 463         return kvm_mips_mkold_pgd(kvm->arch.gpa_mm.pgd,
 464                                   start_gfn << PAGE_SHIFT,
 465                                   end_gfn << PAGE_SHIFT);
 466 }
 467
 468 static int handle_hva_to_gpa(struct kvm *kvm,
 469                              unsigned long start,
 470                              unsigned long end,
 471                              int (*handler)(struct kvm *kvm, gfn_t gfn,
 472                                             gpa_t gfn_end,
 473                                             struct kvm_memory_slot *memslot,
 474                                             void *data),
 475                              void *data)
 476 {
 477         struct kvm_memslots *slots;
 478         struct kvm_memory_slot *memslot;
 479         int ret = 0;
 480
 481         slots = kvm_memslots(kvm);
 482
 483         /* we only care about the pages that the guest sees */
 484         kvm_for_each_memslot(memslot, slots) {
 485                 unsigned long hva_start, hva_end;
 486                 gfn_t gfn, gfn_end;
 487
 488                 hva_start = max(start, memslot->userspace_addr);
 489                 hva_end = min(end, memslot->userspace_addr +
 490                                         (memslot->npages << PAGE_SHIFT));
 491                 if (hva_start >= hva_end)
 492                         continue;
 493
 494                 /*
 495                  * {gfn(page) | page intersects with [hva_start, hva_end)} =
 496                  * {gfn_start, gfn_start+1, ..., gfn_end-1}.
 497                  */
 498                 gfn = hva_to_gfn_memslot(hva_start, memslot);
 499                 gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot);
 500
 501                 ret |= handler(kvm, gfn, gfn_end, memslot, data);
 502         }
 503
 504         return ret;
 505 }
 506
 507
 508 static int kvm_unmap_hva_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end,
 509                                  struct kvm_memory_slot *memslot, void *data)
 510 {
 511         kvm_mips_flush_gpa_pt(kvm, gfn, gfn_end);
 512         return 1;
 513 }
 514
 515 int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end)
 516 {
 517         handle_hva_to_gpa(kvm, start, end, &kvm_unmap_hva_handler, NULL);
 518
 519         kvm_mips_callbacks->flush_shadow_all(kvm);
 520         return 0;
 521 }
 522
 523 static int kvm_set_spte_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end,
 524                                 struct kvm_memory_slot *memslot, void *data)
 525 {
 526         gpa_t gpa = gfn << PAGE_SHIFT;
 527         pte_t hva_pte = *(pte_t *)data;
 528         pte_t *gpa_pte = kvm_mips_pte_for_gpa(kvm, NULL, gpa);
 529         pte_t old_pte;
 530
 531         if (!gpa_pte)
 532                 return 0;
 533
 534         /* Mapping may need adjusting depending on memslot flags */
 535         old_pte = *gpa_pte;
 536         if (memslot->flags & KVM_MEM_LOG_DIRTY_PAGES && !pte_dirty(old_pte))
 537                 hva_pte = pte_mkclean(hva_pte);
 538         else if (memslot->flags & KVM_MEM_READONLY)
 539                 hva_pte = pte_wrprotect(hva_pte);
 540
 541         set_pte(gpa_pte, hva_pte);
 542
 543         /* Replacing an absent or old page doesn't need flushes */
 544         if (!pte_present(old_pte) || !pte_young(old_pte))
 545                 return 0;
 546
 547         /* Pages swapped, aged, moved, or cleaned require flushes */
 548         return !pte_present(hva_pte) ||
 549                !pte_young(hva_pte) ||
 550                pte_pfn(old_pte) != pte_pfn(hva_pte) ||
 551                (pte_dirty(old_pte) && !pte_dirty(hva_pte));
 552 }
 553
 554 void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
 555 {
 556         unsigned long end = hva + PAGE_SIZE;
 557         int ret;
 558
 559         ret = handle_hva_to_gpa(kvm, hva, end, &kvm_set_spte_handler, &pte);
 560         if (ret)
 561                 kvm_mips_callbacks->flush_shadow_all(kvm);
 562 }
 563
 564 static int kvm_age_hva_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end,
 565                                struct kvm_memory_slot *memslot, void *data)
 566 {
 567         return kvm_mips_mkold_gpa_pt(kvm, gfn, gfn_end);
 568 }
 569
 570 static int kvm_test_age_hva_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end,
 571                                     struct kvm_memory_slot *memslot, void *data)
 572 {
 573         gpa_t gpa = gfn << PAGE_SHIFT;
 574         pte_t *gpa_pte = kvm_mips_pte_for_gpa(kvm, NULL, gpa);
 575
 576         if (!gpa_pte)
 577                 return 0;
 578         return pte_young(*gpa_pte);
 579 }
 580
 581 int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end)
 582 {
 583         return handle_hva_to_gpa(kvm, start, end, kvm_age_hva_handler, NULL);
 584 }
 585
 586 int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
 587 {
 588         return handle_hva_to_gpa(kvm, hva, hva, kvm_test_age_hva_handler, NULL);
 589 }
 590
 591 /**
 592  * _kvm_mips_map_page_fast() - Fast path GPA fault handler.
 593  * @vcpu:               VCPU pointer.
 594  * @gpa:                Guest physical address of fault.
 595  * @write_fault:        Whether the fault was due to a write.
 596  * @out_entry:          New PTE for @gpa (written on success unless NULL).
 597  * @out_buddy:          New PTE for @gpa's buddy (written on success unless
 598  *                      NULL).
 599  *
 600  * Perform fast path GPA fault handling, doing all that can be done without
 601  * calling into KVM. This handles marking old pages young (for idle page
 602  * tracking), and dirtying of clean pages (for dirty page logging).
 603  *
 604  * Returns:     0 on success, in which case we can update derived mappings and
 605  *              resume guest execution.
 606  *              -EFAULT on failure due to absent GPA mapping or write to
 607  *              read-only page, in which case KVM must be consulted.
 608  */
 609 static int _kvm_mips_map_page_fast(struct kvm_vcpu *vcpu, unsigned long gpa,
 610                                    bool write_fault,
 611                                    pte_t *out_entry, pte_t *out_buddy)
 612 {
 613         struct kvm *kvm = vcpu->kvm;
 614         gfn_t gfn = gpa >> PAGE_SHIFT;
 615         pte_t *ptep;
 616         kvm_pfn_t pfn = 0;      /* silence bogus GCC warning */
 617         bool pfn_valid = false;
 618         int ret = 0;
 619
 620         spin_lock(&kvm->mmu_lock);
 621
 622         /* Fast path - just check GPA page table for an existing entry */
 623         ptep = kvm_mips_pte_for_gpa(kvm, NULL, gpa);
 624         if (!ptep || !pte_present(*ptep)) {
 625                 ret = -EFAULT;
 626                 goto out;
 627         }
 628
 629         /* Track access to pages marked old */
 630         if (!pte_young(*ptep)) {
 631                 set_pte(ptep, pte_mkyoung(*ptep));
 632                 pfn = pte_pfn(*ptep);
 633                 pfn_valid = true;
 634                 /* call kvm_set_pfn_accessed() after unlock */
 635         }
 636         if (write_fault && !pte_dirty(*ptep)) {
 637                 if (!pte_write(*ptep)) {
 638                         ret = -EFAULT;
 639                         goto out;
 640                 }
 641
 642                 /* Track dirtying of writeable pages */
 643                 set_pte(ptep, pte_mkdirty(*ptep));
 644                 pfn = pte_pfn(*ptep);
 645                 mark_page_dirty(kvm, gfn);
 646                 kvm_set_pfn_dirty(pfn);
 647         }
 648
 649         if (out_entry)
 650                 *out_entry = *ptep;
 651         if (out_buddy)
 652                 *out_buddy = *ptep_buddy(ptep);
 653
 654 out:
 655         spin_unlock(&kvm->mmu_lock);
 656         if (pfn_valid)
 657                 kvm_set_pfn_accessed(pfn);
 658         return ret;
 659 }
 660
 661 /**
 662  * kvm_mips_map_page() - Map a guest physical page.
 663  * @vcpu:               VCPU pointer.
 664  * @gpa:                Guest physical address of fault.
 665  * @write_fault:        Whether the fault was due to a write.
 666  * @out_entry:          New PTE for @gpa (written on success unless NULL).
 667  * @out_buddy:          New PTE for @gpa's buddy (written on success unless
 668  *                      NULL).
 669  *
 670  * Handle GPA faults by creating a new GPA mapping (or updating an existing
 671  * one).
 672  *
 673  * This takes care of marking pages young or dirty (idle/dirty page tracking),
 674  * asking KVM for the corresponding PFN, and creating a mapping in the GPA page
 675  * tables. Derived mappings (GVA page tables and TLBs) must be handled by the
 676  * caller.
 677  *
 678  * Returns:     0 on success, in which case the caller may use the @out_entry
 679  *              and @out_buddy PTEs to update derived mappings and resume guest
 680  *              execution.
 681  *              -EFAULT if there is no memory region at @gpa or a write was
 682  *              attempted to a read-only memory region. This is usually handled
 683  *              as an MMIO access.
 684  */
 685 static int kvm_mips_map_page(struct kvm_vcpu *vcpu, unsigned long gpa,
 686                              bool write_fault,
 687                              pte_t *out_entry, pte_t *out_buddy)
 688 {
 689         struct kvm *kvm = vcpu->kvm;
 690         struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
 691         gfn_t gfn = gpa >> PAGE_SHIFT;
 692         int srcu_idx, err;
 693         kvm_pfn_t pfn;
 694         pte_t *ptep, entry, old_pte;
 695         bool writeable;
 696         unsigned long prot_bits;
 697         unsigned long mmu_seq;
 698
 699         /* Try the fast path to handle old / clean pages */
 700         srcu_idx = srcu_read_lock(&kvm->srcu);
 701         err = _kvm_mips_map_page_fast(vcpu, gpa, write_fault, out_entry,
 702                                       out_buddy);
 703         if (!err)
 704                 goto out;
 705
 706         /* We need a minimum of cached pages ready for page table creation */
 707         err = mmu_topup_memory_cache(memcache, KVM_MMU_CACHE_MIN_PAGES,
 708                                      KVM_NR_MEM_OBJS);
 709         if (err)
 710                 goto out;
 711
 712 retry:
 713         /*
 714          * Used to check for invalidations in progress, of the pfn that is
 715          * returned by pfn_to_pfn_prot below.
 716          */
 717         mmu_seq = kvm->mmu_notifier_seq;
 718         /*
 719          * Ensure the read of mmu_notifier_seq isn't reordered with PTE reads in
 720          * gfn_to_pfn_prot() (which calls get_user_pages()), so that we don't
 721          * risk the page we get a reference to getting unmapped before we have a
 722          * chance to grab the mmu_lock without mmu_notifier_retry() noticing.
 723          *
 724          * This smp_rmb() pairs with the effective smp_wmb() of the combination
 725          * of the pte_unmap_unlock() after the PTE is zapped, and the
 726          * spin_lock() in kvm_mmu_notifier_invalidate_<page|range_end>() before
 727          * mmu_notifier_seq is incremented.
 728          */
 729         smp_rmb();
 730
 731         /* Slow path - ask KVM core whether we can access this GPA */
 732         pfn = gfn_to_pfn_prot(kvm, gfn, write_fault, &writeable);
 733         if (is_error_noslot_pfn(pfn)) {
 734                 err = -EFAULT;
 735                 goto out;
 736         }
 737
 738         spin_lock(&kvm->mmu_lock);
 739         /* Check if an invalidation has taken place since we got pfn */
 740         if (mmu_notifier_retry(kvm, mmu_seq)) {
 741                 /*
 742                  * This can happen when mappings are changed asynchronously, but
 743                  * also synchronously if a COW is triggered by
 744                  * gfn_to_pfn_prot().
 745                  */
 746                 spin_unlock(&kvm->mmu_lock);
 747                 kvm_release_pfn_clean(pfn);
 748                 goto retry;
 749         }
 750
 751         /* Ensure page tables are allocated */
 752         ptep = kvm_mips_pte_for_gpa(kvm, memcache, gpa);
 753
 754         /* Set up the PTE */
 755         prot_bits = _PAGE_PRESENT | __READABLE | _page_cachable_default;
 756         if (writeable) {
 757                 prot_bits |= _PAGE_WRITE;
 758                 if (write_fault) {
 759                         prot_bits |= __WRITEABLE;
 760                         mark_page_dirty(kvm, gfn);
 761                         kvm_set_pfn_dirty(pfn);
 762                 }
 763         }
 764         entry = pfn_pte(pfn, __pgprot(prot_bits));
 765
 766         /* Write the PTE */
 767         old_pte = *ptep;
 768         set_pte(ptep, entry);
 769
 770         err = 0;
 771         if (out_entry)
 772                 *out_entry = *ptep;
 773         if (out_buddy)
 774                 *out_buddy = *ptep_buddy(ptep);
 775
 776         spin_unlock(&kvm->mmu_lock);
 777         kvm_release_pfn_clean(pfn);
 778         kvm_set_pfn_accessed(pfn);
 779 out:
 780         srcu_read_unlock(&kvm->srcu, srcu_idx);
 781         return err;
 782 }
 783
 784 static pte_t *kvm_trap_emul_pte_for_gva(struct kvm_vcpu *vcpu,
 785                                         unsigned long addr)
 786 {
 787         struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
 788         pgd_t *pgdp;
 789         int ret;
 790
 791         /* We need a minimum of cached pages ready for page table creation */
 792         ret = mmu_topup_memory_cache(memcache, KVM_MMU_CACHE_MIN_PAGES,
 793                                      KVM_NR_MEM_OBJS);
 794         if (ret)
 795                 return NULL;
 796
 797         if (KVM_GUEST_KERNEL_MODE(vcpu))
 798                 pgdp = vcpu->arch.guest_kernel_mm.pgd;
 799         else
 800                 pgdp = vcpu->arch.guest_user_mm.pgd;
 801
 802         return kvm_mips_walk_pgd(pgdp, memcache, addr);
 803 }
 804
 805 void kvm_trap_emul_invalidate_gva(struct kvm_vcpu *vcpu, unsigned long addr,
 806                                   bool user)
 807 {
 808         pgd_t *pgdp;
 809         pte_t *ptep;
 810
 811         addr &= PAGE_MASK << 1;
 812
 813         pgdp = vcpu->arch.guest_kernel_mm.pgd;
 814         ptep = kvm_mips_walk_pgd(pgdp, NULL, addr);
 815         if (ptep) {
 816                 ptep[0] = pfn_pte(0, __pgprot(0));
 817                 ptep[1] = pfn_pte(0, __pgprot(0));
 818         }
 819
 820         if (user) {
 821                 pgdp = vcpu->arch.guest_user_mm.pgd;
 822                 ptep = kvm_mips_walk_pgd(pgdp, NULL, addr);
 823                 if (ptep) {
 824                         ptep[0] = pfn_pte(0, __pgprot(0));
 825                         ptep[1] = pfn_pte(0, __pgprot(0));
 826                 }
 827         }
 828 }
 829
 830 /*
 831  * kvm_mips_flush_gva_{pte,pmd,pud,pgd,pt}.
 832  * Flush a range of guest physical address space from the VM's GPA page tables.
 833  */
 834
 835 static bool kvm_mips_flush_gva_pte(pte_t *pte, unsigned long start_gva,
 836                                    unsigned long end_gva)
 837 {
 838         int i_min = __pte_offset(start_gva);
 839         int i_max = __pte_offset(end_gva);
 840         bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PTE - 1);
 841         int i;
 842
 843         /*
 844          * There's no freeing to do, so there's no point clearing individual
 845          * entries unless only part of the last level page table needs flushing.
 846          */
 847         if (safe_to_remove)
 848                 return true;
 849
 850         for (i = i_min; i <= i_max; ++i) {
 851                 if (!pte_present(pte[i]))
 852                         continue;
 853
 854                 set_pte(pte + i, __pte(0));
 855         }
 856         return false;
 857 }
 858
 859 static bool kvm_mips_flush_gva_pmd(pmd_t *pmd, unsigned long start_gva,
 860                                    unsigned long end_gva)
 861 {
 862         pte_t *pte;
 863         unsigned long end = ~0ul;
 864         int i_min = __pmd_offset(start_gva);
 865         int i_max = __pmd_offset(end_gva);
 866         bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PMD - 1);
 867         int i;
 868
 869         for (i = i_min; i <= i_max; ++i, start_gva = 0) {
 870                 if (!pmd_present(pmd[i]))
 871                         continue;
 872
 873                 pte = pte_offset(pmd + i, 0);
 874                 if (i == i_max)
 875                         end = end_gva;
 876
 877                 if (kvm_mips_flush_gva_pte(pte, start_gva, end)) {
 878                         pmd_clear(pmd + i);
 879                         pte_free_kernel(NULL, pte);
 880                 } else {
 881                         safe_to_remove = false;
 882                 }
 883         }
 884         return safe_to_remove;
 885 }
 886
 887 static bool kvm_mips_flush_gva_pud(pud_t *pud, unsigned long start_gva,
 888                                    unsigned long end_gva)
 889 {
 890         pmd_t *pmd;
 891         unsigned long end = ~0ul;
 892         int i_min = __pud_offset(start_gva);
 893         int i_max = __pud_offset(end_gva);
 894         bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PUD - 1);
 895         int i;
 896
 897         for (i = i_min; i <= i_max; ++i, start_gva = 0) {
 898                 if (!pud_present(pud[i]))
 899                         continue;
 900
 901                 pmd = pmd_offset(pud + i, 0);
 902                 if (i == i_max)
 903                         end = end_gva;
 904
 905                 if (kvm_mips_flush_gva_pmd(pmd, start_gva, end)) {
 906                         pud_clear(pud + i);
 907                         pmd_free(NULL, pmd);
 908                 } else {
 909                         safe_to_remove = false;
 910                 }
 911         }
 912         return safe_to_remove;
 913 }
 914
 915 static bool kvm_mips_flush_gva_pgd(pgd_t *pgd, unsigned long start_gva,
 916                                    unsigned long end_gva)
 917 {
 918         pud_t *pud;
 919         unsigned long end = ~0ul;
 920         int i_min = pgd_index(start_gva);
 921         int i_max = pgd_index(end_gva);
 922         bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PGD - 1);
 923         int i;
 924
 925         for (i = i_min; i <= i_max; ++i, start_gva = 0) {
 926                 if (!pgd_present(pgd[i]))
 927                         continue;
 928
 929                 pud = pud_offset(pgd + i, 0);
 930                 if (i == i_max)
 931                         end = end_gva;
 932
 933                 if (kvm_mips_flush_gva_pud(pud, start_gva, end)) {
 934                         pgd_clear(pgd + i);
 935                         pud_free(NULL, pud);
 936                 } else {
 937                         safe_to_remove = false;
 938                 }
 939         }
 940         return safe_to_remove;
 941 }
 942
 943 void kvm_mips_flush_gva_pt(pgd_t *pgd, enum kvm_mips_flush flags)
 944 {
 945         if (flags & KMF_GPA) {
 946                 /* all of guest virtual address space could be affected */
 947                 if (flags & KMF_KERN)
 948                         /* useg, kseg0, seg2/3 */
 949                         kvm_mips_flush_gva_pgd(pgd, 0, 0x7fffffff);
 950                 else
 951                         /* useg */
 952                         kvm_mips_flush_gva_pgd(pgd, 0, 0x3fffffff);
 953         } else {
 954                 /* useg */
 955                 kvm_mips_flush_gva_pgd(pgd, 0, 0x3fffffff);
 956
 957                 /* kseg2/3 */
 958                 if (flags & KMF_KERN)
 959                         kvm_mips_flush_gva_pgd(pgd, 0x60000000, 0x7fffffff);
 960         }
 961 }
 962
 963 static pte_t kvm_mips_gpa_pte_to_gva_unmapped(pte_t pte)
 964 {
 965         /*
 966          * Don't leak writeable but clean entries from GPA page tables. We don't
 967          * want the normal Linux tlbmod handler to handle dirtying when KVM
 968          * accesses guest memory.
 969          */
 970         if (!pte_dirty(pte))
 971                 pte = pte_wrprotect(pte);
 972
 973         return pte;
 974 }
 975
 976 static pte_t kvm_mips_gpa_pte_to_gva_mapped(pte_t pte, long entrylo)
 977 {
 978         /* Guest EntryLo overrides host EntryLo */
 979         if (!(entrylo & ENTRYLO_D))
 980                 pte = pte_mkclean(pte);
 981
 982         return kvm_mips_gpa_pte_to_gva_unmapped(pte);
 983 }
 984
 985 #ifdef CONFIG_KVM_MIPS_VZ
 986 int kvm_mips_handle_vz_root_tlb_fault(unsigned long badvaddr,
 987                                       struct kvm_vcpu *vcpu,
 988                                       bool write_fault)
 989 {
 990         int ret;
 991
 992         ret = kvm_mips_map_page(vcpu, badvaddr, write_fault, NULL, NULL);
 993         if (ret)
 994                 return ret;
 995
 996         /* Invalidate this entry in the TLB */
 997         return kvm_vz_host_tlb_inv(vcpu, badvaddr);
 998 }
 999 #endif
1000
1001 /* XXXKYMA: Must be called with interrupts disabled */
1002 int kvm_mips_handle_kseg0_tlb_fault(unsigned long badvaddr,
1003                                     struct kvm_vcpu *vcpu,
1004                                     bool write_fault)
1005 {
1006         unsigned long gpa;
1007         pte_t pte_gpa[2], *ptep_gva;
1008         int idx;
1009
1010         if (KVM_GUEST_KSEGX(badvaddr) != KVM_GUEST_KSEG0) {
1011                 kvm_err("%s: Invalid BadVaddr: %#lx\n", __func__, badvaddr);
1012                 kvm_mips_dump_host_tlbs();
1013                 return -1;
1014         }
1015
1016         /* Get the GPA page table entry */
1017         gpa = KVM_GUEST_CPHYSADDR(badvaddr);
1018         idx = (badvaddr >> PAGE_SHIFT) & 1;
1019         if (kvm_mips_map_page(vcpu, gpa, write_fault, &pte_gpa[idx],
1020                               &pte_gpa[!idx]) < 0)
1021                 return -1;
1022
1023         /* Get the GVA page table entry */
1024         ptep_gva = kvm_trap_emul_pte_for_gva(vcpu, badvaddr & ~PAGE_SIZE);
1025         if (!ptep_gva) {
1026                 kvm_err("No ptep for gva %lx\n", badvaddr);
1027                 return -1;
1028         }
1029
1030         /* Copy a pair of entries from GPA page table to GVA page table */
1031         ptep_gva[0] = kvm_mips_gpa_pte_to_gva_unmapped(pte_gpa[0]);
1032         ptep_gva[1] = kvm_mips_gpa_pte_to_gva_unmapped(pte_gpa[1]);
1033
1034         /* Invalidate this entry in the TLB, guest kernel ASID only */
1035         kvm_mips_host_tlb_inv(vcpu, badvaddr, false, true);
1036         return 0;
1037 }
1038
1039 int kvm_mips_handle_mapped_seg_tlb_fault(struct kvm_vcpu *vcpu,
1040                                          struct kvm_mips_tlb *tlb,
1041                                          unsigned long gva,
1042                                          bool write_fault)
1043 {
1044         struct kvm *kvm = vcpu->kvm;
1045         long tlb_lo[2];
1046         pte_t pte_gpa[2], *ptep_buddy, *ptep_gva;
1047         unsigned int idx = TLB_LO_IDX(*tlb, gva);
1048         bool kernel = KVM_GUEST_KERNEL_MODE(vcpu);
1049
1050         tlb_lo[0] = tlb->tlb_lo[0];
1051         tlb_lo[1] = tlb->tlb_lo[1];
1052
1053         /*
1054          * The commpage address must not be mapped to anything else if the guest
1055          * TLB contains entries nearby, or commpage accesses will break.
1056          */
1057         if (!((gva ^ KVM_GUEST_COMMPAGE_ADDR) & VPN2_MASK & (PAGE_MASK << 1)))
1058                 tlb_lo[TLB_LO_IDX(*tlb, KVM_GUEST_COMMPAGE_ADDR)] = 0;
1059
1060         /* Get the GPA page table entry */
1061         if (kvm_mips_map_page(vcpu, mips3_tlbpfn_to_paddr(tlb_lo[idx]),
1062                               write_fault, &pte_gpa[idx], NULL) < 0)
1063                 return -1;
1064
1065         /* And its GVA buddy's GPA page table entry if it also exists */
1066         pte_gpa[!idx] = pfn_pte(0, __pgprot(0));
1067         if (tlb_lo[!idx] & ENTRYLO_V) {
1068                 spin_lock(&kvm->mmu_lock);
1069                 ptep_buddy = kvm_mips_pte_for_gpa(kvm, NULL,
1070                                         mips3_tlbpfn_to_paddr(tlb_lo[!idx]));
1071                 if (ptep_buddy)
1072                         pte_gpa[!idx] = *ptep_buddy;
1073                 spin_unlock(&kvm->mmu_lock);
1074         }
1075
1076         /* Get the GVA page table entry pair */
1077         ptep_gva = kvm_trap_emul_pte_for_gva(vcpu, gva & ~PAGE_SIZE);
1078         if (!ptep_gva) {
1079                 kvm_err("No ptep for gva %lx\n", gva);
1080                 return -1;
1081         }
1082
1083         /* Copy a pair of entries from GPA page table to GVA page table */
1084         ptep_gva[0] = kvm_mips_gpa_pte_to_gva_mapped(pte_gpa[0], tlb_lo[0]);
1085         ptep_gva[1] = kvm_mips_gpa_pte_to_gva_mapped(pte_gpa[1], tlb_lo[1]);
1086
1087         /* Invalidate this entry in the TLB, current guest mode ASID only */
1088         kvm_mips_host_tlb_inv(vcpu, gva, !kernel, kernel);
1089
1090         kvm_debug("@ %#lx tlb_lo0: 0x%08lx tlb_lo1: 0x%08lx\n", vcpu->arch.pc,
1091                   tlb->tlb_lo[0], tlb->tlb_lo[1]);
1092
1093         return 0;
1094 }
1095
1096 int kvm_mips_handle_commpage_tlb_fault(unsigned long badvaddr,
1097                                        struct kvm_vcpu *vcpu)
1098 {
1099         kvm_pfn_t pfn;
1100         pte_t *ptep;
1101
1102         ptep = kvm_trap_emul_pte_for_gva(vcpu, badvaddr);
1103         if (!ptep) {
1104                 kvm_err("No ptep for commpage %lx\n", badvaddr);
1105                 return -1;
1106         }
1107
1108         pfn = PFN_DOWN(virt_to_phys(vcpu->arch.kseg0_commpage));
1109         /* Also set valid and dirty, so refill handler doesn't have to */
1110         *ptep = pte_mkyoung(pte_mkdirty(pfn_pte(pfn, PAGE_SHARED)));
1111
1112         /* Invalidate this entry in the TLB, guest kernel ASID only */
1113         kvm_mips_host_tlb_inv(vcpu, badvaddr, false, true);
1114         return 0;
1115 }
1116
1117 /**
1118  * kvm_mips_migrate_count() - Migrate timer.
1119  * @vcpu:       Virtual CPU.
1120  *
1121  * Migrate CP0_Count hrtimer to the current CPU by cancelling and restarting it
1122  * if it was running prior to being cancelled.
1123  *
1124  * Must be called when the VCPU is migrated to a different CPU to ensure that
1125  * timer expiry during guest execution interrupts the guest and causes the
1126  * interrupt to be delivered in a timely manner.
1127  */
1128 static void kvm_mips_migrate_count(struct kvm_vcpu *vcpu)
1129 {
1130         if (hrtimer_cancel(&vcpu->arch.comparecount_timer))
1131                 hrtimer_restart(&vcpu->arch.comparecount_timer);
1132 }
1133
1134 /* Restore ASID once we are scheduled back after preemption */
1135 void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
1136 {
1137         unsigned long flags;
1138
1139         kvm_debug("%s: vcpu %p, cpu: %d\n", __func__, vcpu, cpu);
1140
1141         local_irq_save(flags);
1142
1143         vcpu->cpu = cpu;
1144         if (vcpu->arch.last_sched_cpu != cpu) {
1145                 kvm_debug("[%d->%d]KVM VCPU[%d] switch\n",
1146                           vcpu->arch.last_sched_cpu, cpu, vcpu->vcpu_id);
1147                 /*
1148                  * Migrate the timer interrupt to the current CPU so that it
1149                  * always interrupts the guest and synchronously triggers a
1150                  * guest timer interrupt.
1151                  */
1152                 kvm_mips_migrate_count(vcpu);
1153         }
1154
1155         /* restore guest state to registers */
1156         kvm_mips_callbacks->vcpu_load(vcpu, cpu);
1157
1158         local_irq_restore(flags);
1159 }
1160
1161 /* ASID can change if another task is scheduled during preemption */
1162 void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
1163 {
1164         unsigned long flags;
1165         int cpu;
1166
1167         local_irq_save(flags);
1168
1169         cpu = smp_processor_id();
1170         vcpu->arch.last_sched_cpu = cpu;
1171         vcpu->cpu = -1;
1172
1173         /* save guest state in registers */
1174         kvm_mips_callbacks->vcpu_put(vcpu, cpu);
1175
1176         local_irq_restore(flags);
1177 }
1178
1179 /**
1180  * kvm_trap_emul_gva_fault() - Safely attempt to handle a GVA access fault.
1181  * @vcpu:       Virtual CPU.
1182  * @gva:        Guest virtual address to be accessed.
1183  * @write:      True if write attempted (must be dirtied and made writable).
1184  *
1185  * Safely attempt to handle a GVA fault, mapping GVA pages if necessary, and
1186  * dirtying the page if @write so that guest instructions can be modified.
1187  *
1188  * Returns:     KVM_MIPS_MAPPED on success.
1189  *              KVM_MIPS_GVA if bad guest virtual address.
1190  *              KVM_MIPS_GPA if bad guest physical address.
1191  *              KVM_MIPS_TLB if guest TLB not present.
1192  *              KVM_MIPS_TLBINV if guest TLB present but not valid.
1193  *              KVM_MIPS_TLBMOD if guest TLB read only.
1194  */
1195 enum kvm_mips_fault_result kvm_trap_emul_gva_fault(struct kvm_vcpu *vcpu,
1196                                                    unsigned long gva,
1197                                                    bool write)
1198 {
1199         struct mips_coproc *cop0 = vcpu->arch.cop0;
1200         struct kvm_mips_tlb *tlb;
1201         int index;
1202
1203         if (KVM_GUEST_KSEGX(gva) == KVM_GUEST_KSEG0) {
1204                 if (kvm_mips_handle_kseg0_tlb_fault(gva, vcpu, write) < 0)
1205                         return KVM_MIPS_GPA;
1206         } else if ((KVM_GUEST_KSEGX(gva) < KVM_GUEST_KSEG0) ||
1207                    KVM_GUEST_KSEGX(gva) == KVM_GUEST_KSEG23) {
1208                 /* Address should be in the guest TLB */
1209                 index = kvm_mips_guest_tlb_lookup(vcpu, (gva & VPN2_MASK) |
1210                           (kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID));
1211                 if (index < 0)
1212                         return KVM_MIPS_TLB;
1213                 tlb = &vcpu->arch.guest_tlb[index];
1214
1215                 /* Entry should be valid, and dirty for writes */
1216                 if (!TLB_IS_VALID(*tlb, gva))
1217                         return KVM_MIPS_TLBINV;
1218                 if (write && !TLB_IS_DIRTY(*tlb, gva))
1219                         return KVM_MIPS_TLBMOD;
1220
1221                 if (kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb, gva, write))
1222                         return KVM_MIPS_GPA;
1223         } else {
1224                 return KVM_MIPS_GVA;
1225         }
1226
1227         return KVM_MIPS_MAPPED;
1228 }
1229
1230 int kvm_get_inst(u32 *opc, struct kvm_vcpu *vcpu, u32 *out)
1231 {
1232         int err;
1233
1234         if (WARN(IS_ENABLED(CONFIG_KVM_MIPS_VZ),
1235                  "Expect BadInstr/BadInstrP registers to be used with VZ\n"))
1236                 return -EINVAL;
1237
1238 retry:
1239         kvm_trap_emul_gva_lockless_begin(vcpu);
1240         err = get_user(*out, opc);
1241         kvm_trap_emul_gva_lockless_end(vcpu);
1242
1243         if (unlikely(err)) {
1244                 /*
1245                  * Try to handle the fault, maybe we just raced with a GVA
1246                  * invalidation.
1247                  */
1248                 err = kvm_trap_emul_gva_fault(vcpu, (unsigned long)opc,
1249                                               false);
1250                 if (unlikely(err)) {
1251                         kvm_err("%s: illegal address: %p\n",
1252                                 __func__, opc);
1253                         return -EFAULT;
1254                 }
1255
1256                 /* Hopefully it'll work now */
1257                 goto retry;
1258         }
1259         return 0;
1260 }