linux/arch/mips/kvm/mmu.c
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   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
  28static 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
  45static 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
  51static 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
  60void 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 */
  75static 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 */
 111pgd_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 */
 136static 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 */
 173static 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
 185static 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
 202static 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
 230static 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
 258static 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 */
 299bool 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)                                    \
 307static 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 */                                 \
 331static 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                                                                        \
 354static 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                                                                        \
 377static 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
 406BUILD_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 */
 423int 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 */
 441void 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
 458BUILD_PTE_RANGE_OP(mkold, pte_mkold)
 459
 460static 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
 468static 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
 508static 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
 515int 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
 523static 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
 554int 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        return 0;
 563}
 564
 565static int kvm_age_hva_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end,
 566                               struct kvm_memory_slot *memslot, void *data)
 567{
 568        return kvm_mips_mkold_gpa_pt(kvm, gfn, gfn_end);
 569}
 570
 571static int kvm_test_age_hva_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end,
 572                                    struct kvm_memory_slot *memslot, void *data)
 573{
 574        gpa_t gpa = gfn << PAGE_SHIFT;
 575        pte_t *gpa_pte = kvm_mips_pte_for_gpa(kvm, NULL, gpa);
 576
 577        if (!gpa_pte)
 578                return 0;
 579        return pte_young(*gpa_pte);
 580}
 581
 582int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end)
 583{
 584        return handle_hva_to_gpa(kvm, start, end, kvm_age_hva_handler, NULL);
 585}
 586
 587int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
 588{
 589        return handle_hva_to_gpa(kvm, hva, hva, kvm_test_age_hva_handler, NULL);
 590}
 591
 592/**
 593 * _kvm_mips_map_page_fast() - Fast path GPA fault handler.
 594 * @vcpu:               VCPU pointer.
 595 * @gpa:                Guest physical address of fault.
 596 * @write_fault:        Whether the fault was due to a write.
 597 * @out_entry:          New PTE for @gpa (written on success unless NULL).
 598 * @out_buddy:          New PTE for @gpa's buddy (written on success unless
 599 *                      NULL).
 600 *
 601 * Perform fast path GPA fault handling, doing all that can be done without
 602 * calling into KVM. This handles marking old pages young (for idle page
 603 * tracking), and dirtying of clean pages (for dirty page logging).
 604 *
 605 * Returns:     0 on success, in which case we can update derived mappings and
 606 *              resume guest execution.
 607 *              -EFAULT on failure due to absent GPA mapping or write to
 608 *              read-only page, in which case KVM must be consulted.
 609 */
 610static int _kvm_mips_map_page_fast(struct kvm_vcpu *vcpu, unsigned long gpa,
 611                                   bool write_fault,
 612                                   pte_t *out_entry, pte_t *out_buddy)
 613{
 614        struct kvm *kvm = vcpu->kvm;
 615        gfn_t gfn = gpa >> PAGE_SHIFT;
 616        pte_t *ptep;
 617        kvm_pfn_t pfn = 0;      /* silence bogus GCC warning */
 618        bool pfn_valid = false;
 619        int ret = 0;
 620
 621        spin_lock(&kvm->mmu_lock);
 622
 623        /* Fast path - just check GPA page table for an existing entry */
 624        ptep = kvm_mips_pte_for_gpa(kvm, NULL, gpa);
 625        if (!ptep || !pte_present(*ptep)) {
 626                ret = -EFAULT;
 627                goto out;
 628        }
 629
 630        /* Track access to pages marked old */
 631        if (!pte_young(*ptep)) {
 632                set_pte(ptep, pte_mkyoung(*ptep));
 633                pfn = pte_pfn(*ptep);
 634                pfn_valid = true;
 635                /* call kvm_set_pfn_accessed() after unlock */
 636        }
 637        if (write_fault && !pte_dirty(*ptep)) {
 638                if (!pte_write(*ptep)) {
 639                        ret = -EFAULT;
 640                        goto out;
 641                }
 642
 643                /* Track dirtying of writeable pages */
 644                set_pte(ptep, pte_mkdirty(*ptep));
 645                pfn = pte_pfn(*ptep);
 646                mark_page_dirty(kvm, gfn);
 647                kvm_set_pfn_dirty(pfn);
 648        }
 649
 650        if (out_entry)
 651                *out_entry = *ptep;
 652        if (out_buddy)
 653                *out_buddy = *ptep_buddy(ptep);
 654
 655out:
 656        spin_unlock(&kvm->mmu_lock);
 657        if (pfn_valid)
 658                kvm_set_pfn_accessed(pfn);
 659        return ret;
 660}
 661
 662/**
 663 * kvm_mips_map_page() - Map a guest physical page.
 664 * @vcpu:               VCPU pointer.
 665 * @gpa:                Guest physical address of fault.
 666 * @write_fault:        Whether the fault was due to a write.
 667 * @out_entry:          New PTE for @gpa (written on success unless NULL).
 668 * @out_buddy:          New PTE for @gpa's buddy (written on success unless
 669 *                      NULL).
 670 *
 671 * Handle GPA faults by creating a new GPA mapping (or updating an existing
 672 * one).
 673 *
 674 * This takes care of marking pages young or dirty (idle/dirty page tracking),
 675 * asking KVM for the corresponding PFN, and creating a mapping in the GPA page
 676 * tables. Derived mappings (GVA page tables and TLBs) must be handled by the
 677 * caller.
 678 *
 679 * Returns:     0 on success, in which case the caller may use the @out_entry
 680 *              and @out_buddy PTEs to update derived mappings and resume guest
 681 *              execution.
 682 *              -EFAULT if there is no memory region at @gpa or a write was
 683 *              attempted to a read-only memory region. This is usually handled
 684 *              as an MMIO access.
 685 */
 686static int kvm_mips_map_page(struct kvm_vcpu *vcpu, unsigned long gpa,
 687                             bool write_fault,
 688                             pte_t *out_entry, pte_t *out_buddy)
 689{
 690        struct kvm *kvm = vcpu->kvm;
 691        struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
 692        gfn_t gfn = gpa >> PAGE_SHIFT;
 693        int srcu_idx, err;
 694        kvm_pfn_t pfn;
 695        pte_t *ptep, entry, old_pte;
 696        bool writeable;
 697        unsigned long prot_bits;
 698        unsigned long mmu_seq;
 699
 700        /* Try the fast path to handle old / clean pages */
 701        srcu_idx = srcu_read_lock(&kvm->srcu);
 702        err = _kvm_mips_map_page_fast(vcpu, gpa, write_fault, out_entry,
 703                                      out_buddy);
 704        if (!err)
 705                goto out;
 706
 707        /* We need a minimum of cached pages ready for page table creation */
 708        err = mmu_topup_memory_cache(memcache, KVM_MMU_CACHE_MIN_PAGES,
 709                                     KVM_NR_MEM_OBJS);
 710        if (err)
 711                goto out;
 712
 713retry:
 714        /*
 715         * Used to check for invalidations in progress, of the pfn that is
 716         * returned by pfn_to_pfn_prot below.
 717         */
 718        mmu_seq = kvm->mmu_notifier_seq;
 719        /*
 720         * Ensure the read of mmu_notifier_seq isn't reordered with PTE reads in
 721         * gfn_to_pfn_prot() (which calls get_user_pages()), so that we don't
 722         * risk the page we get a reference to getting unmapped before we have a
 723         * chance to grab the mmu_lock without mmu_notifier_retry() noticing.
 724         *
 725         * This smp_rmb() pairs with the effective smp_wmb() of the combination
 726         * of the pte_unmap_unlock() after the PTE is zapped, and the
 727         * spin_lock() in kvm_mmu_notifier_invalidate_<page|range_end>() before
 728         * mmu_notifier_seq is incremented.
 729         */
 730        smp_rmb();
 731
 732        /* Slow path - ask KVM core whether we can access this GPA */
 733        pfn = gfn_to_pfn_prot(kvm, gfn, write_fault, &writeable);
 734        if (is_error_noslot_pfn(pfn)) {
 735                err = -EFAULT;
 736                goto out;
 737        }
 738
 739        spin_lock(&kvm->mmu_lock);
 740        /* Check if an invalidation has taken place since we got pfn */
 741        if (mmu_notifier_retry(kvm, mmu_seq)) {
 742                /*
 743                 * This can happen when mappings are changed asynchronously, but
 744                 * also synchronously if a COW is triggered by
 745                 * gfn_to_pfn_prot().
 746                 */
 747                spin_unlock(&kvm->mmu_lock);
 748                kvm_release_pfn_clean(pfn);
 749                goto retry;
 750        }
 751
 752        /* Ensure page tables are allocated */
 753        ptep = kvm_mips_pte_for_gpa(kvm, memcache, gpa);
 754
 755        /* Set up the PTE */
 756        prot_bits = _PAGE_PRESENT | __READABLE | _page_cachable_default;
 757        if (writeable) {
 758                prot_bits |= _PAGE_WRITE;
 759                if (write_fault) {
 760                        prot_bits |= __WRITEABLE;
 761                        mark_page_dirty(kvm, gfn);
 762                        kvm_set_pfn_dirty(pfn);
 763                }
 764        }
 765        entry = pfn_pte(pfn, __pgprot(prot_bits));
 766
 767        /* Write the PTE */
 768        old_pte = *ptep;
 769        set_pte(ptep, entry);
 770
 771        err = 0;
 772        if (out_entry)
 773                *out_entry = *ptep;
 774        if (out_buddy)
 775                *out_buddy = *ptep_buddy(ptep);
 776
 777        spin_unlock(&kvm->mmu_lock);
 778        kvm_release_pfn_clean(pfn);
 779        kvm_set_pfn_accessed(pfn);
 780out:
 781        srcu_read_unlock(&kvm->srcu, srcu_idx);
 782        return err;
 783}
 784
 785static pte_t *kvm_trap_emul_pte_for_gva(struct kvm_vcpu *vcpu,
 786                                        unsigned long addr)
 787{
 788        struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
 789        pgd_t *pgdp;
 790        int ret;
 791
 792        /* We need a minimum of cached pages ready for page table creation */
 793        ret = mmu_topup_memory_cache(memcache, KVM_MMU_CACHE_MIN_PAGES,
 794                                     KVM_NR_MEM_OBJS);
 795        if (ret)
 796                return NULL;
 797
 798        if (KVM_GUEST_KERNEL_MODE(vcpu))
 799                pgdp = vcpu->arch.guest_kernel_mm.pgd;
 800        else
 801                pgdp = vcpu->arch.guest_user_mm.pgd;
 802
 803        return kvm_mips_walk_pgd(pgdp, memcache, addr);
 804}
 805
 806void kvm_trap_emul_invalidate_gva(struct kvm_vcpu *vcpu, unsigned long addr,
 807                                  bool user)
 808{
 809        pgd_t *pgdp;
 810        pte_t *ptep;
 811
 812        addr &= PAGE_MASK << 1;
 813
 814        pgdp = vcpu->arch.guest_kernel_mm.pgd;
 815        ptep = kvm_mips_walk_pgd(pgdp, NULL, addr);
 816        if (ptep) {
 817                ptep[0] = pfn_pte(0, __pgprot(0));
 818                ptep[1] = pfn_pte(0, __pgprot(0));
 819        }
 820
 821        if (user) {
 822                pgdp = vcpu->arch.guest_user_mm.pgd;
 823                ptep = kvm_mips_walk_pgd(pgdp, NULL, addr);
 824                if (ptep) {
 825                        ptep[0] = pfn_pte(0, __pgprot(0));
 826                        ptep[1] = pfn_pte(0, __pgprot(0));
 827                }
 828        }
 829}
 830
 831/*
 832 * kvm_mips_flush_gva_{pte,pmd,pud,pgd,pt}.
 833 * Flush a range of guest physical address space from the VM's GPA page tables.
 834 */
 835
 836static bool kvm_mips_flush_gva_pte(pte_t *pte, unsigned long start_gva,
 837                                   unsigned long end_gva)
 838{
 839        int i_min = __pte_offset(start_gva);
 840        int i_max = __pte_offset(end_gva);
 841        bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PTE - 1);
 842        int i;
 843
 844        /*
 845         * There's no freeing to do, so there's no point clearing individual
 846         * entries unless only part of the last level page table needs flushing.
 847         */
 848        if (safe_to_remove)
 849                return true;
 850
 851        for (i = i_min; i <= i_max; ++i) {
 852                if (!pte_present(pte[i]))
 853                        continue;
 854
 855                set_pte(pte + i, __pte(0));
 856        }
 857        return false;
 858}
 859
 860static bool kvm_mips_flush_gva_pmd(pmd_t *pmd, unsigned long start_gva,
 861                                   unsigned long end_gva)
 862{
 863        pte_t *pte;
 864        unsigned long end = ~0ul;
 865        int i_min = __pmd_offset(start_gva);
 866        int i_max = __pmd_offset(end_gva);
 867        bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PMD - 1);
 868        int i;
 869
 870        for (i = i_min; i <= i_max; ++i, start_gva = 0) {
 871                if (!pmd_present(pmd[i]))
 872                        continue;
 873
 874                pte = pte_offset(pmd + i, 0);
 875                if (i == i_max)
 876                        end = end_gva;
 877
 878                if (kvm_mips_flush_gva_pte(pte, start_gva, end)) {
 879                        pmd_clear(pmd + i);
 880                        pte_free_kernel(NULL, pte);
 881                } else {
 882                        safe_to_remove = false;
 883                }
 884        }
 885        return safe_to_remove;
 886}
 887
 888static bool kvm_mips_flush_gva_pud(pud_t *pud, unsigned long start_gva,
 889                                   unsigned long end_gva)
 890{
 891        pmd_t *pmd;
 892        unsigned long end = ~0ul;
 893        int i_min = __pud_offset(start_gva);
 894        int i_max = __pud_offset(end_gva);
 895        bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PUD - 1);
 896        int i;
 897
 898        for (i = i_min; i <= i_max; ++i, start_gva = 0) {
 899                if (!pud_present(pud[i]))
 900                        continue;
 901
 902                pmd = pmd_offset(pud + i, 0);
 903                if (i == i_max)
 904                        end = end_gva;
 905
 906                if (kvm_mips_flush_gva_pmd(pmd, start_gva, end)) {
 907                        pud_clear(pud + i);
 908                        pmd_free(NULL, pmd);
 909                } else {
 910                        safe_to_remove = false;
 911                }
 912        }
 913        return safe_to_remove;
 914}
 915
 916static bool kvm_mips_flush_gva_pgd(pgd_t *pgd, unsigned long start_gva,
 917                                   unsigned long end_gva)
 918{
 919        pud_t *pud;
 920        unsigned long end = ~0ul;
 921        int i_min = pgd_index(start_gva);
 922        int i_max = pgd_index(end_gva);
 923        bool safe_to_remove = (i_min == 0 && i_max == PTRS_PER_PGD - 1);
 924        int i;
 925
 926        for (i = i_min; i <= i_max; ++i, start_gva = 0) {
 927                if (!pgd_present(pgd[i]))
 928                        continue;
 929
 930                pud = pud_offset(pgd + i, 0);
 931                if (i == i_max)
 932                        end = end_gva;
 933
 934                if (kvm_mips_flush_gva_pud(pud, start_gva, end)) {
 935                        pgd_clear(pgd + i);
 936                        pud_free(NULL, pud);
 937                } else {
 938                        safe_to_remove = false;
 939                }
 940        }
 941        return safe_to_remove;
 942}
 943
 944void kvm_mips_flush_gva_pt(pgd_t *pgd, enum kvm_mips_flush flags)
 945{
 946        if (flags & KMF_GPA) {
 947                /* all of guest virtual address space could be affected */
 948                if (flags & KMF_KERN)
 949                        /* useg, kseg0, seg2/3 */
 950                        kvm_mips_flush_gva_pgd(pgd, 0, 0x7fffffff);
 951                else
 952                        /* useg */
 953                        kvm_mips_flush_gva_pgd(pgd, 0, 0x3fffffff);
 954        } else {
 955                /* useg */
 956                kvm_mips_flush_gva_pgd(pgd, 0, 0x3fffffff);
 957
 958                /* kseg2/3 */
 959                if (flags & KMF_KERN)
 960                        kvm_mips_flush_gva_pgd(pgd, 0x60000000, 0x7fffffff);
 961        }
 962}
 963
 964static pte_t kvm_mips_gpa_pte_to_gva_unmapped(pte_t pte)
 965{
 966        /*
 967         * Don't leak writeable but clean entries from GPA page tables. We don't
 968         * want the normal Linux tlbmod handler to handle dirtying when KVM
 969         * accesses guest memory.
 970         */
 971        if (!pte_dirty(pte))
 972                pte = pte_wrprotect(pte);
 973
 974        return pte;
 975}
 976
 977static pte_t kvm_mips_gpa_pte_to_gva_mapped(pte_t pte, long entrylo)
 978{
 979        /* Guest EntryLo overrides host EntryLo */
 980        if (!(entrylo & ENTRYLO_D))
 981                pte = pte_mkclean(pte);
 982
 983        return kvm_mips_gpa_pte_to_gva_unmapped(pte);
 984}
 985
 986#ifdef CONFIG_KVM_MIPS_VZ
 987int kvm_mips_handle_vz_root_tlb_fault(unsigned long badvaddr,
 988                                      struct kvm_vcpu *vcpu,
 989                                      bool write_fault)
 990{
 991        int ret;
 992
 993        ret = kvm_mips_map_page(vcpu, badvaddr, write_fault, NULL, NULL);
 994        if (ret)
 995                return ret;
 996
 997        /* Invalidate this entry in the TLB */
 998        return kvm_vz_host_tlb_inv(vcpu, badvaddr);
 999}
1000#endif
1001
1002/* XXXKYMA: Must be called with interrupts disabled */
1003int kvm_mips_handle_kseg0_tlb_fault(unsigned long badvaddr,
1004                                    struct kvm_vcpu *vcpu,
1005                                    bool write_fault)
1006{
1007        unsigned long gpa;
1008        pte_t pte_gpa[2], *ptep_gva;
1009        int idx;
1010
1011        if (KVM_GUEST_KSEGX(badvaddr) != KVM_GUEST_KSEG0) {
1012                kvm_err("%s: Invalid BadVaddr: %#lx\n", __func__, badvaddr);
1013                kvm_mips_dump_host_tlbs();
1014                return -1;
1015        }
1016
1017        /* Get the GPA page table entry */
1018        gpa = KVM_GUEST_CPHYSADDR(badvaddr);
1019        idx = (badvaddr >> PAGE_SHIFT) & 1;
1020        if (kvm_mips_map_page(vcpu, gpa, write_fault, &pte_gpa[idx],
1021                              &pte_gpa[!idx]) < 0)
1022                return -1;
1023
1024        /* Get the GVA page table entry */
1025        ptep_gva = kvm_trap_emul_pte_for_gva(vcpu, badvaddr & ~PAGE_SIZE);
1026        if (!ptep_gva) {
1027                kvm_err("No ptep for gva %lx\n", badvaddr);
1028                return -1;
1029        }
1030
1031        /* Copy a pair of entries from GPA page table to GVA page table */
1032        ptep_gva[0] = kvm_mips_gpa_pte_to_gva_unmapped(pte_gpa[0]);
1033        ptep_gva[1] = kvm_mips_gpa_pte_to_gva_unmapped(pte_gpa[1]);
1034
1035        /* Invalidate this entry in the TLB, guest kernel ASID only */
1036        kvm_mips_host_tlb_inv(vcpu, badvaddr, false, true);
1037        return 0;
1038}
1039
1040int kvm_mips_handle_mapped_seg_tlb_fault(struct kvm_vcpu *vcpu,
1041                                         struct kvm_mips_tlb *tlb,
1042                                         unsigned long gva,
1043                                         bool write_fault)
1044{
1045        struct kvm *kvm = vcpu->kvm;
1046        long tlb_lo[2];
1047        pte_t pte_gpa[2], *ptep_buddy, *ptep_gva;
1048        unsigned int idx = TLB_LO_IDX(*tlb, gva);
1049        bool kernel = KVM_GUEST_KERNEL_MODE(vcpu);
1050
1051        tlb_lo[0] = tlb->tlb_lo[0];
1052        tlb_lo[1] = tlb->tlb_lo[1];
1053
1054        /*
1055         * The commpage address must not be mapped to anything else if the guest
1056         * TLB contains entries nearby, or commpage accesses will break.
1057         */
1058        if (!((gva ^ KVM_GUEST_COMMPAGE_ADDR) & VPN2_MASK & (PAGE_MASK << 1)))
1059                tlb_lo[TLB_LO_IDX(*tlb, KVM_GUEST_COMMPAGE_ADDR)] = 0;
1060
1061        /* Get the GPA page table entry */
1062        if (kvm_mips_map_page(vcpu, mips3_tlbpfn_to_paddr(tlb_lo[idx]),
1063                              write_fault, &pte_gpa[idx], NULL) < 0)
1064                return -1;
1065
1066        /* And its GVA buddy's GPA page table entry if it also exists */
1067        pte_gpa[!idx] = pfn_pte(0, __pgprot(0));
1068        if (tlb_lo[!idx] & ENTRYLO_V) {
1069                spin_lock(&kvm->mmu_lock);
1070                ptep_buddy = kvm_mips_pte_for_gpa(kvm, NULL,
1071                                        mips3_tlbpfn_to_paddr(tlb_lo[!idx]));
1072                if (ptep_buddy)
1073                        pte_gpa[!idx] = *ptep_buddy;
1074                spin_unlock(&kvm->mmu_lock);
1075        }
1076
1077        /* Get the GVA page table entry pair */
1078        ptep_gva = kvm_trap_emul_pte_for_gva(vcpu, gva & ~PAGE_SIZE);
1079        if (!ptep_gva) {
1080                kvm_err("No ptep for gva %lx\n", gva);
1081                return -1;
1082        }
1083
1084        /* Copy a pair of entries from GPA page table to GVA page table */
1085        ptep_gva[0] = kvm_mips_gpa_pte_to_gva_mapped(pte_gpa[0], tlb_lo[0]);
1086        ptep_gva[1] = kvm_mips_gpa_pte_to_gva_mapped(pte_gpa[1], tlb_lo[1]);
1087
1088        /* Invalidate this entry in the TLB, current guest mode ASID only */
1089        kvm_mips_host_tlb_inv(vcpu, gva, !kernel, kernel);
1090
1091        kvm_debug("@ %#lx tlb_lo0: 0x%08lx tlb_lo1: 0x%08lx\n", vcpu->arch.pc,
1092                  tlb->tlb_lo[0], tlb->tlb_lo[1]);
1093
1094        return 0;
1095}
1096
1097int kvm_mips_handle_commpage_tlb_fault(unsigned long badvaddr,
1098                                       struct kvm_vcpu *vcpu)
1099{
1100        kvm_pfn_t pfn;
1101        pte_t *ptep;
1102
1103        ptep = kvm_trap_emul_pte_for_gva(vcpu, badvaddr);
1104        if (!ptep) {
1105                kvm_err("No ptep for commpage %lx\n", badvaddr);
1106                return -1;
1107        }
1108
1109        pfn = PFN_DOWN(virt_to_phys(vcpu->arch.kseg0_commpage));
1110        /* Also set valid and dirty, so refill handler doesn't have to */
1111        *ptep = pte_mkyoung(pte_mkdirty(pfn_pte(pfn, PAGE_SHARED)));
1112
1113        /* Invalidate this entry in the TLB, guest kernel ASID only */
1114        kvm_mips_host_tlb_inv(vcpu, badvaddr, false, true);
1115        return 0;
1116}
1117
1118/**
1119 * kvm_mips_migrate_count() - Migrate timer.
1120 * @vcpu:       Virtual CPU.
1121 *
1122 * Migrate CP0_Count hrtimer to the current CPU by cancelling and restarting it
1123 * if it was running prior to being cancelled.
1124 *
1125 * Must be called when the VCPU is migrated to a different CPU to ensure that
1126 * timer expiry during guest execution interrupts the guest and causes the
1127 * interrupt to be delivered in a timely manner.
1128 */
1129static void kvm_mips_migrate_count(struct kvm_vcpu *vcpu)
1130{
1131        if (hrtimer_cancel(&vcpu->arch.comparecount_timer))
1132                hrtimer_restart(&vcpu->arch.comparecount_timer);
1133}
1134
1135/* Restore ASID once we are scheduled back after preemption */
1136void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
1137{
1138        unsigned long flags;
1139
1140        kvm_debug("%s: vcpu %p, cpu: %d\n", __func__, vcpu, cpu);
1141
1142        local_irq_save(flags);
1143
1144        vcpu->cpu = cpu;
1145        if (vcpu->arch.last_sched_cpu != cpu) {
1146                kvm_debug("[%d->%d]KVM VCPU[%d] switch\n",
1147                          vcpu->arch.last_sched_cpu, cpu, vcpu->vcpu_id);
1148                /*
1149                 * Migrate the timer interrupt to the current CPU so that it
1150                 * always interrupts the guest and synchronously triggers a
1151                 * guest timer interrupt.
1152                 */
1153                kvm_mips_migrate_count(vcpu);
1154        }
1155
1156        /* restore guest state to registers */
1157        kvm_mips_callbacks->vcpu_load(vcpu, cpu);
1158
1159        local_irq_restore(flags);
1160}
1161
1162/* ASID can change if another task is scheduled during preemption */
1163void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
1164{
1165        unsigned long flags;
1166        int cpu;
1167
1168        local_irq_save(flags);
1169
1170        cpu = smp_processor_id();
1171        vcpu->arch.last_sched_cpu = cpu;
1172        vcpu->cpu = -1;
1173
1174        /* save guest state in registers */
1175        kvm_mips_callbacks->vcpu_put(vcpu, cpu);
1176
1177        local_irq_restore(flags);
1178}
1179
1180/**
1181 * kvm_trap_emul_gva_fault() - Safely attempt to handle a GVA access fault.
1182 * @vcpu:       Virtual CPU.
1183 * @gva:        Guest virtual address to be accessed.
1184 * @write:      True if write attempted (must be dirtied and made writable).
1185 *
1186 * Safely attempt to handle a GVA fault, mapping GVA pages if necessary, and
1187 * dirtying the page if @write so that guest instructions can be modified.
1188 *
1189 * Returns:     KVM_MIPS_MAPPED on success.
1190 *              KVM_MIPS_GVA if bad guest virtual address.
1191 *              KVM_MIPS_GPA if bad guest physical address.
1192 *              KVM_MIPS_TLB if guest TLB not present.
1193 *              KVM_MIPS_TLBINV if guest TLB present but not valid.
1194 *              KVM_MIPS_TLBMOD if guest TLB read only.
1195 */
1196enum kvm_mips_fault_result kvm_trap_emul_gva_fault(struct kvm_vcpu *vcpu,
1197                                                   unsigned long gva,
1198                                                   bool write)
1199{
1200        struct mips_coproc *cop0 = vcpu->arch.cop0;
1201        struct kvm_mips_tlb *tlb;
1202        int index;
1203
1204        if (KVM_GUEST_KSEGX(gva) == KVM_GUEST_KSEG0) {
1205                if (kvm_mips_handle_kseg0_tlb_fault(gva, vcpu, write) < 0)
1206                        return KVM_MIPS_GPA;
1207        } else if ((KVM_GUEST_KSEGX(gva) < KVM_GUEST_KSEG0) ||
1208                   KVM_GUEST_KSEGX(gva) == KVM_GUEST_KSEG23) {
1209                /* Address should be in the guest TLB */
1210                index = kvm_mips_guest_tlb_lookup(vcpu, (gva & VPN2_MASK) |
1211                          (kvm_read_c0_guest_entryhi(cop0) & KVM_ENTRYHI_ASID));
1212                if (index < 0)
1213                        return KVM_MIPS_TLB;
1214                tlb = &vcpu->arch.guest_tlb[index];
1215
1216                /* Entry should be valid, and dirty for writes */
1217                if (!TLB_IS_VALID(*tlb, gva))
1218                        return KVM_MIPS_TLBINV;
1219                if (write && !TLB_IS_DIRTY(*tlb, gva))
1220                        return KVM_MIPS_TLBMOD;
1221
1222                if (kvm_mips_handle_mapped_seg_tlb_fault(vcpu, tlb, gva, write))
1223                        return KVM_MIPS_GPA;
1224        } else {
1225                return KVM_MIPS_GVA;
1226        }
1227
1228        return KVM_MIPS_MAPPED;
1229}
1230
1231int kvm_get_inst(u32 *opc, struct kvm_vcpu *vcpu, u32 *out)
1232{
1233        int err;
1234
1235        if (WARN(IS_ENABLED(CONFIG_KVM_MIPS_VZ),
1236                 "Expect BadInstr/BadInstrP registers to be used with VZ\n"))
1237                return -EINVAL;
1238
1239retry:
1240        kvm_trap_emul_gva_lockless_begin(vcpu);
1241        err = get_user(*out, opc);
1242        kvm_trap_emul_gva_lockless_end(vcpu);
1243
1244        if (unlikely(err)) {
1245                /*
1246                 * Try to handle the fault, maybe we just raced with a GVA
1247                 * invalidation.
1248                 */
1249                err = kvm_trap_emul_gva_fault(vcpu, (unsigned long)opc,
1250                                              false);
1251                if (unlikely(err)) {
1252                        kvm_err("%s: illegal address: %p\n",
1253                                __func__, opc);
1254                        return -EFAULT;
1255                }
1256
1257                /* Hopefully it'll work now */
1258                goto retry;
1259        }
1260        return 0;
1261}
1262