arch/arm64/kvm/hyp/pgtable.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Stand-alone page-table allocator for hyp stage-1 and guest stage-2.
   4  * No bombay mix was harmed in the writing of this file.
   5  *
   6  * Copyright (C) 2020 Google LLC
   7  * Author: Will Deacon <will@kernel.org>
   8  */
   9
  10 #include <linux/bitfield.h>
  11 #include <asm/kvm_pgtable.h>
  12 #include <asm/stage2_pgtable.h>
  13
  14
  15 #define KVM_PTE_TYPE                    BIT(1)
  16 #define KVM_PTE_TYPE_BLOCK              0
  17 #define KVM_PTE_TYPE_PAGE               1
  18 #define KVM_PTE_TYPE_TABLE              1
  19
  20 #define KVM_PTE_LEAF_ATTR_LO            GENMASK(11, 2)
  21
  22 #define KVM_PTE_LEAF_ATTR_LO_S1_ATTRIDX GENMASK(4, 2)
  23 #define KVM_PTE_LEAF_ATTR_LO_S1_AP      GENMASK(7, 6)
  24 #define KVM_PTE_LEAF_ATTR_LO_S1_AP_RO   3
  25 #define KVM_PTE_LEAF_ATTR_LO_S1_AP_RW   1
  26 #define KVM_PTE_LEAF_ATTR_LO_S1_SH      GENMASK(9, 8)
  27 #define KVM_PTE_LEAF_ATTR_LO_S1_SH_IS   3
  28 #define KVM_PTE_LEAF_ATTR_LO_S1_AF      BIT(10)
  29
  30 #define KVM_PTE_LEAF_ATTR_LO_S2_MEMATTR GENMASK(5, 2)
  31 #define KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R  BIT(6)
  32 #define KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W  BIT(7)
  33 #define KVM_PTE_LEAF_ATTR_LO_S2_SH      GENMASK(9, 8)
  34 #define KVM_PTE_LEAF_ATTR_LO_S2_SH_IS   3
  35 #define KVM_PTE_LEAF_ATTR_LO_S2_AF      BIT(10)
  36
  37 #define KVM_PTE_LEAF_ATTR_HI            GENMASK(63, 51)
  38
  39 #define KVM_PTE_LEAF_ATTR_HI_SW         GENMASK(58, 55)
  40
  41 #define KVM_PTE_LEAF_ATTR_HI_S1_XN      BIT(54)
  42
  43 #define KVM_PTE_LEAF_ATTR_HI_S2_XN      BIT(54)
  44
  45 #define KVM_PTE_LEAF_ATTR_S2_PERMS      (KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | \
  46                                          KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | \
  47                                          KVM_PTE_LEAF_ATTR_HI_S2_XN)
  48
  49 #define KVM_INVALID_PTE_OWNER_MASK      GENMASK(9, 2)
  50 #define KVM_MAX_OWNER_ID                1
  51
  52 struct kvm_pgtable_walk_data {
  53         struct kvm_pgtable              *pgt;
  54         struct kvm_pgtable_walker       *walker;
  55
  56         u64                             addr;
  57         u64                             end;
  58 };
  59
  60 #define KVM_PHYS_INVALID (-1ULL)
  61
  62 static bool kvm_phys_is_valid(u64 phys)
  63 {
  64         return phys < BIT(id_aa64mmfr0_parange_to_phys_shift(ID_AA64MMFR0_PARANGE_MAX));
  65 }
  66
  67 static bool kvm_block_mapping_supported(u64 addr, u64 end, u64 phys, u32 level)
  68 {
  69         u64 granule = kvm_granule_size(level);
  70
  71         if (!kvm_level_supports_block_mapping(level))
  72                 return false;
  73
  74         if (granule > (end - addr))
  75                 return false;
  76
  77         if (kvm_phys_is_valid(phys) && !IS_ALIGNED(phys, granule))
  78                 return false;
  79
  80         return IS_ALIGNED(addr, granule);
  81 }
  82
  83 static u32 kvm_pgtable_idx(struct kvm_pgtable_walk_data *data, u32 level)
  84 {
  85         u64 shift = kvm_granule_shift(level);
  86         u64 mask = BIT(PAGE_SHIFT - 3) - 1;
  87
  88         return (data->addr >> shift) & mask;
  89 }
  90
  91 static u32 __kvm_pgd_page_idx(struct kvm_pgtable *pgt, u64 addr)
  92 {
  93         u64 shift = kvm_granule_shift(pgt->start_level - 1); /* May underflow */
  94         u64 mask = BIT(pgt->ia_bits) - 1;
  95
  96         return (addr & mask) >> shift;
  97 }
  98
  99 static u32 kvm_pgd_page_idx(struct kvm_pgtable_walk_data *data)
 100 {
 101         return __kvm_pgd_page_idx(data->pgt, data->addr);
 102 }
 103
 104 static u32 kvm_pgd_pages(u32 ia_bits, u32 start_level)
 105 {
 106         struct kvm_pgtable pgt = {
 107                 .ia_bits        = ia_bits,
 108                 .start_level    = start_level,
 109         };
 110
 111         return __kvm_pgd_page_idx(&pgt, -1ULL) + 1;
 112 }
 113
 114 static bool kvm_pte_table(kvm_pte_t pte, u32 level)
 115 {
 116         if (level == KVM_PGTABLE_MAX_LEVELS - 1)
 117                 return false;
 118
 119         if (!kvm_pte_valid(pte))
 120                 return false;
 121
 122         return FIELD_GET(KVM_PTE_TYPE, pte) == KVM_PTE_TYPE_TABLE;
 123 }
 124
 125 static kvm_pte_t kvm_phys_to_pte(u64 pa)
 126 {
 127         kvm_pte_t pte = pa & KVM_PTE_ADDR_MASK;
 128
 129         if (PAGE_SHIFT == 16)
 130                 pte |= FIELD_PREP(KVM_PTE_ADDR_51_48, pa >> 48);
 131
 132         return pte;
 133 }
 134
 135 static kvm_pte_t *kvm_pte_follow(kvm_pte_t pte, struct kvm_pgtable_mm_ops *mm_ops)
 136 {
 137         return mm_ops->phys_to_virt(kvm_pte_to_phys(pte));
 138 }
 139
 140 static void kvm_clear_pte(kvm_pte_t *ptep)
 141 {
 142         WRITE_ONCE(*ptep, 0);
 143 }
 144
 145 static void kvm_set_table_pte(kvm_pte_t *ptep, kvm_pte_t *childp,
 146                               struct kvm_pgtable_mm_ops *mm_ops)
 147 {
 148         kvm_pte_t old = *ptep, pte = kvm_phys_to_pte(mm_ops->virt_to_phys(childp));
 149
 150         pte |= FIELD_PREP(KVM_PTE_TYPE, KVM_PTE_TYPE_TABLE);
 151         pte |= KVM_PTE_VALID;
 152
 153         WARN_ON(kvm_pte_valid(old));
 154         smp_store_release(ptep, pte);
 155 }
 156
 157 static kvm_pte_t kvm_init_valid_leaf_pte(u64 pa, kvm_pte_t attr, u32 level)
 158 {
 159         kvm_pte_t pte = kvm_phys_to_pte(pa);
 160         u64 type = (level == KVM_PGTABLE_MAX_LEVELS - 1) ? KVM_PTE_TYPE_PAGE :
 161                                                            KVM_PTE_TYPE_BLOCK;
 162
 163         pte |= attr & (KVM_PTE_LEAF_ATTR_LO | KVM_PTE_LEAF_ATTR_HI);
 164         pte |= FIELD_PREP(KVM_PTE_TYPE, type);
 165         pte |= KVM_PTE_VALID;
 166
 167         return pte;
 168 }
 169
 170 static kvm_pte_t kvm_init_invalid_leaf_owner(u8 owner_id)
 171 {
 172         return FIELD_PREP(KVM_INVALID_PTE_OWNER_MASK, owner_id);
 173 }
 174
 175 static int kvm_pgtable_visitor_cb(struct kvm_pgtable_walk_data *data, u64 addr,
 176                                   u32 level, kvm_pte_t *ptep,
 177                                   enum kvm_pgtable_walk_flags flag)
 178 {
 179         struct kvm_pgtable_walker *walker = data->walker;
 180         return walker->cb(addr, data->end, level, ptep, flag, walker->arg);
 181 }
 182
 183 static int __kvm_pgtable_walk(struct kvm_pgtable_walk_data *data,
 184                               kvm_pte_t *pgtable, u32 level);
 185
 186 static inline int __kvm_pgtable_visit(struct kvm_pgtable_walk_data *data,
 187                                       kvm_pte_t *ptep, u32 level)
 188 {
 189         int ret = 0;
 190         u64 addr = data->addr;
 191         kvm_pte_t *childp, pte = *ptep;
 192         bool table = kvm_pte_table(pte, level);
 193         enum kvm_pgtable_walk_flags flags = data->walker->flags;
 194
 195         if (table && (flags & KVM_PGTABLE_WALK_TABLE_PRE)) {
 196                 ret = kvm_pgtable_visitor_cb(data, addr, level, ptep,
 197                                              KVM_PGTABLE_WALK_TABLE_PRE);
 198         }
 199
 200         if (!table && (flags & KVM_PGTABLE_WALK_LEAF)) {
 201                 ret = kvm_pgtable_visitor_cb(data, addr, level, ptep,
 202                                              KVM_PGTABLE_WALK_LEAF);
 203                 pte = *ptep;
 204                 table = kvm_pte_table(pte, level);
 205         }
 206
 207         if (ret)
 208                 goto out;
 209
 210         if (!table) {
 211                 data->addr = ALIGN_DOWN(data->addr, kvm_granule_size(level));
 212                 data->addr += kvm_granule_size(level);
 213                 goto out;
 214         }
 215
 216         childp = kvm_pte_follow(pte, data->pgt->mm_ops);
 217         ret = __kvm_pgtable_walk(data, childp, level + 1);
 218         if (ret)
 219                 goto out;
 220
 221         if (flags & KVM_PGTABLE_WALK_TABLE_POST) {
 222                 ret = kvm_pgtable_visitor_cb(data, addr, level, ptep,
 223                                              KVM_PGTABLE_WALK_TABLE_POST);
 224         }
 225
 226 out:
 227         return ret;
 228 }
 229
 230 static int __kvm_pgtable_walk(struct kvm_pgtable_walk_data *data,
 231                               kvm_pte_t *pgtable, u32 level)
 232 {
 233         u32 idx;
 234         int ret = 0;
 235
 236         if (WARN_ON_ONCE(level >= KVM_PGTABLE_MAX_LEVELS))
 237                 return -EINVAL;
 238
 239         for (idx = kvm_pgtable_idx(data, level); idx < PTRS_PER_PTE; ++idx) {
 240                 kvm_pte_t *ptep = &pgtable[idx];
 241
 242                 if (data->addr >= data->end)
 243                         break;
 244
 245                 ret = __kvm_pgtable_visit(data, ptep, level);
 246                 if (ret)
 247                         break;
 248         }
 249
 250         return ret;
 251 }
 252
 253 static int _kvm_pgtable_walk(struct kvm_pgtable_walk_data *data)
 254 {
 255         u32 idx;
 256         int ret = 0;
 257         struct kvm_pgtable *pgt = data->pgt;
 258         u64 limit = BIT(pgt->ia_bits);
 259
 260         if (data->addr > limit || data->end > limit)
 261                 return -ERANGE;
 262
 263         if (!pgt->pgd)
 264                 return -EINVAL;
 265
 266         for (idx = kvm_pgd_page_idx(data); data->addr < data->end; ++idx) {
 267                 kvm_pte_t *ptep = &pgt->pgd[idx * PTRS_PER_PTE];
 268
 269                 ret = __kvm_pgtable_walk(data, ptep, pgt->start_level);
 270                 if (ret)
 271                         break;
 272         }
 273
 274         return ret;
 275 }
 276
 277 int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size,
 278                      struct kvm_pgtable_walker *walker)
 279 {
 280         struct kvm_pgtable_walk_data walk_data = {
 281                 .pgt    = pgt,
 282                 .addr   = ALIGN_DOWN(addr, PAGE_SIZE),
 283                 .end    = PAGE_ALIGN(walk_data.addr + size),
 284                 .walker = walker,
 285         };
 286
 287         return _kvm_pgtable_walk(&walk_data);
 288 }
 289
 290 struct leaf_walk_data {
 291         kvm_pte_t       pte;
 292         u32             level;
 293 };
 294
 295 static int leaf_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
 296                        enum kvm_pgtable_walk_flags flag, void * const arg)
 297 {
 298         struct leaf_walk_data *data = arg;
 299
 300         data->pte   = *ptep;
 301         data->level = level;
 302
 303         return 0;
 304 }
 305
 306 int kvm_pgtable_get_leaf(struct kvm_pgtable *pgt, u64 addr,
 307                          kvm_pte_t *ptep, u32 *level)
 308 {
 309         struct leaf_walk_data data;
 310         struct kvm_pgtable_walker walker = {
 311                 .cb     = leaf_walker,
 312                 .flags  = KVM_PGTABLE_WALK_LEAF,
 313                 .arg    = &data,
 314         };
 315         int ret;
 316
 317         ret = kvm_pgtable_walk(pgt, ALIGN_DOWN(addr, PAGE_SIZE),
 318                                PAGE_SIZE, &walker);
 319         if (!ret) {
 320                 if (ptep)
 321                         *ptep  = data.pte;
 322                 if (level)
 323                         *level = data.level;
 324         }
 325
 326         return ret;
 327 }
 328
 329 struct hyp_map_data {
 330         u64                             phys;
 331         kvm_pte_t                       attr;
 332         struct kvm_pgtable_mm_ops       *mm_ops;
 333 };
 334
 335 static int hyp_set_prot_attr(enum kvm_pgtable_prot prot, kvm_pte_t *ptep)
 336 {
 337         bool device = prot & KVM_PGTABLE_PROT_DEVICE;
 338         u32 mtype = device ? MT_DEVICE_nGnRE : MT_NORMAL;
 339         kvm_pte_t attr = FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_ATTRIDX, mtype);
 340         u32 sh = KVM_PTE_LEAF_ATTR_LO_S1_SH_IS;
 341         u32 ap = (prot & KVM_PGTABLE_PROT_W) ? KVM_PTE_LEAF_ATTR_LO_S1_AP_RW :
 342                                                KVM_PTE_LEAF_ATTR_LO_S1_AP_RO;
 343
 344         if (!(prot & KVM_PGTABLE_PROT_R))
 345                 return -EINVAL;
 346
 347         if (prot & KVM_PGTABLE_PROT_X) {
 348                 if (prot & KVM_PGTABLE_PROT_W)
 349                         return -EINVAL;
 350
 351                 if (device)
 352                         return -EINVAL;
 353         } else {
 354                 attr |= KVM_PTE_LEAF_ATTR_HI_S1_XN;
 355         }
 356
 357         attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_AP, ap);
 358         attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_SH, sh);
 359         attr |= KVM_PTE_LEAF_ATTR_LO_S1_AF;
 360         attr |= prot & KVM_PTE_LEAF_ATTR_HI_SW;
 361         *ptep = attr;
 362
 363         return 0;
 364 }
 365
 366 enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte)
 367 {
 368         enum kvm_pgtable_prot prot = pte & KVM_PTE_LEAF_ATTR_HI_SW;
 369         u32 ap;
 370
 371         if (!kvm_pte_valid(pte))
 372                 return prot;
 373
 374         if (!(pte & KVM_PTE_LEAF_ATTR_HI_S1_XN))
 375                 prot |= KVM_PGTABLE_PROT_X;
 376
 377         ap = FIELD_GET(KVM_PTE_LEAF_ATTR_LO_S1_AP, pte);
 378         if (ap == KVM_PTE_LEAF_ATTR_LO_S1_AP_RO)
 379                 prot |= KVM_PGTABLE_PROT_R;
 380         else if (ap == KVM_PTE_LEAF_ATTR_LO_S1_AP_RW)
 381                 prot |= KVM_PGTABLE_PROT_RW;
 382
 383         return prot;
 384 }
 385
 386 static bool hyp_pte_needs_update(kvm_pte_t old, kvm_pte_t new)
 387 {
 388         /*
 389          * Tolerate KVM recreating the exact same mapping, or changing software
 390          * bits if the existing mapping was valid.
 391          */
 392         if (old == new)
 393                 return false;
 394
 395         if (!kvm_pte_valid(old))
 396                 return true;
 397
 398         return !WARN_ON((old ^ new) & ~KVM_PTE_LEAF_ATTR_HI_SW);
 399 }
 400
 401 static bool hyp_map_walker_try_leaf(u64 addr, u64 end, u32 level,
 402                                     kvm_pte_t *ptep, struct hyp_map_data *data)
 403 {
 404         kvm_pte_t new, old = *ptep;
 405         u64 granule = kvm_granule_size(level), phys = data->phys;
 406
 407         if (!kvm_block_mapping_supported(addr, end, phys, level))
 408                 return false;
 409
 410         new = kvm_init_valid_leaf_pte(phys, data->attr, level);
 411         if (hyp_pte_needs_update(old, new))
 412                 smp_store_release(ptep, new);
 413
 414         data->phys += granule;
 415         return true;
 416 }
 417
 418 static int hyp_map_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
 419                           enum kvm_pgtable_walk_flags flag, void * const arg)
 420 {
 421         kvm_pte_t *childp;
 422         struct hyp_map_data *data = arg;
 423         struct kvm_pgtable_mm_ops *mm_ops = data->mm_ops;
 424
 425         if (hyp_map_walker_try_leaf(addr, end, level, ptep, arg))
 426                 return 0;
 427
 428         if (WARN_ON(level == KVM_PGTABLE_MAX_LEVELS - 1))
 429                 return -EINVAL;
 430
 431         childp = (kvm_pte_t *)mm_ops->zalloc_page(NULL);
 432         if (!childp)
 433                 return -ENOMEM;
 434
 435         kvm_set_table_pte(ptep, childp, mm_ops);
 436         return 0;
 437 }
 438
 439 int kvm_pgtable_hyp_map(struct kvm_pgtable *pgt, u64 addr, u64 size, u64 phys,
 440                         enum kvm_pgtable_prot prot)
 441 {
 442         int ret;
 443         struct hyp_map_data map_data = {
 444                 .phys   = ALIGN_DOWN(phys, PAGE_SIZE),
 445                 .mm_ops = pgt->mm_ops,
 446         };
 447         struct kvm_pgtable_walker walker = {
 448                 .cb     = hyp_map_walker,
 449                 .flags  = KVM_PGTABLE_WALK_LEAF,
 450                 .arg    = &map_data,
 451         };
 452
 453         ret = hyp_set_prot_attr(prot, &map_data.attr);
 454         if (ret)
 455                 return ret;
 456
 457         ret = kvm_pgtable_walk(pgt, addr, size, &walker);
 458         dsb(ishst);
 459         isb();
 460         return ret;
 461 }
 462
 463 int kvm_pgtable_hyp_init(struct kvm_pgtable *pgt, u32 va_bits,
 464                          struct kvm_pgtable_mm_ops *mm_ops)
 465 {
 466         u64 levels = ARM64_HW_PGTABLE_LEVELS(va_bits);
 467
 468         pgt->pgd = (kvm_pte_t *)mm_ops->zalloc_page(NULL);
 469         if (!pgt->pgd)
 470                 return -ENOMEM;
 471
 472         pgt->ia_bits            = va_bits;
 473         pgt->start_level        = KVM_PGTABLE_MAX_LEVELS - levels;
 474         pgt->mm_ops             = mm_ops;
 475         pgt->mmu                = NULL;
 476         pgt->force_pte_cb       = NULL;
 477
 478         return 0;
 479 }
 480
 481 static int hyp_free_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
 482                            enum kvm_pgtable_walk_flags flag, void * const arg)
 483 {
 484         struct kvm_pgtable_mm_ops *mm_ops = arg;
 485
 486         mm_ops->put_page((void *)kvm_pte_follow(*ptep, mm_ops));
 487         return 0;
 488 }
 489
 490 void kvm_pgtable_hyp_destroy(struct kvm_pgtable *pgt)
 491 {
 492         struct kvm_pgtable_walker walker = {
 493                 .cb     = hyp_free_walker,
 494                 .flags  = KVM_PGTABLE_WALK_TABLE_POST,
 495                 .arg    = pgt->mm_ops,
 496         };
 497
 498         WARN_ON(kvm_pgtable_walk(pgt, 0, BIT(pgt->ia_bits), &walker));
 499         pgt->mm_ops->put_page(pgt->pgd);
 500         pgt->pgd = NULL;
 501 }
 502
 503 struct stage2_map_data {
 504         u64                             phys;
 505         kvm_pte_t                       attr;
 506         u8                              owner_id;
 507
 508         kvm_pte_t                       *anchor;
 509         kvm_pte_t                       *childp;
 510
 511         struct kvm_s2_mmu               *mmu;
 512         void                            *memcache;
 513
 514         struct kvm_pgtable_mm_ops       *mm_ops;
 515
 516         /* Force mappings to page granularity */
 517         bool                            force_pte;
 518 };
 519
 520 u64 kvm_get_vtcr(u64 mmfr0, u64 mmfr1, u32 phys_shift)
 521 {
 522         u64 vtcr = VTCR_EL2_FLAGS;
 523         u8 lvls;
 524
 525         vtcr |= kvm_get_parange(mmfr0) << VTCR_EL2_PS_SHIFT;
 526         vtcr |= VTCR_EL2_T0SZ(phys_shift);
 527         /*
 528          * Use a minimum 2 level page table to prevent splitting
 529          * host PMD huge pages at stage2.
 530          */
 531         lvls = stage2_pgtable_levels(phys_shift);
 532         if (lvls < 2)
 533                 lvls = 2;
 534         vtcr |= VTCR_EL2_LVLS_TO_SL0(lvls);
 535
 536         /*
 537          * Enable the Hardware Access Flag management, unconditionally
 538          * on all CPUs. The features is RES0 on CPUs without the support
 539          * and must be ignored by the CPUs.
 540          */
 541         vtcr |= VTCR_EL2_HA;
 542
 543         /* Set the vmid bits */
 544         vtcr |= (get_vmid_bits(mmfr1) == 16) ?
 545                 VTCR_EL2_VS_16BIT :
 546                 VTCR_EL2_VS_8BIT;
 547
 548         return vtcr;
 549 }
 550
 551 static bool stage2_has_fwb(struct kvm_pgtable *pgt)
 552 {
 553         if (!cpus_have_const_cap(ARM64_HAS_STAGE2_FWB))
 554                 return false;
 555
 556         return !(pgt->flags & KVM_PGTABLE_S2_NOFWB);
 557 }
 558
 559 #define KVM_S2_MEMATTR(pgt, attr) PAGE_S2_MEMATTR(attr, stage2_has_fwb(pgt))
 560
 561 static int stage2_set_prot_attr(struct kvm_pgtable *pgt, enum kvm_pgtable_prot prot,
 562                                 kvm_pte_t *ptep)
 563 {
 564         bool device = prot & KVM_PGTABLE_PROT_DEVICE;
 565         kvm_pte_t attr = device ? KVM_S2_MEMATTR(pgt, DEVICE_nGnRE) :
 566                             KVM_S2_MEMATTR(pgt, NORMAL);
 567         u32 sh = KVM_PTE_LEAF_ATTR_LO_S2_SH_IS;
 568
 569         if (!(prot & KVM_PGTABLE_PROT_X))
 570                 attr |= KVM_PTE_LEAF_ATTR_HI_S2_XN;
 571         else if (device)
 572                 return -EINVAL;
 573
 574         if (prot & KVM_PGTABLE_PROT_R)
 575                 attr |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R;
 576
 577         if (prot & KVM_PGTABLE_PROT_W)
 578                 attr |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W;
 579
 580         attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S2_SH, sh);
 581         attr |= KVM_PTE_LEAF_ATTR_LO_S2_AF;
 582         attr |= prot & KVM_PTE_LEAF_ATTR_HI_SW;
 583         *ptep = attr;
 584
 585         return 0;
 586 }
 587
 588 enum kvm_pgtable_prot kvm_pgtable_stage2_pte_prot(kvm_pte_t pte)
 589 {
 590         enum kvm_pgtable_prot prot = pte & KVM_PTE_LEAF_ATTR_HI_SW;
 591
 592         if (!kvm_pte_valid(pte))
 593                 return prot;
 594
 595         if (pte & KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R)
 596                 prot |= KVM_PGTABLE_PROT_R;
 597         if (pte & KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W)
 598                 prot |= KVM_PGTABLE_PROT_W;
 599         if (!(pte & KVM_PTE_LEAF_ATTR_HI_S2_XN))
 600                 prot |= KVM_PGTABLE_PROT_X;
 601
 602         return prot;
 603 }
 604
 605 static bool stage2_pte_needs_update(kvm_pte_t old, kvm_pte_t new)
 606 {
 607         if (!kvm_pte_valid(old) || !kvm_pte_valid(new))
 608                 return true;
 609
 610         return ((old ^ new) & (~KVM_PTE_LEAF_ATTR_S2_PERMS));
 611 }
 612
 613 static bool stage2_pte_is_counted(kvm_pte_t pte)
 614 {
 615         /*
 616          * The refcount tracks valid entries as well as invalid entries if they
 617          * encode ownership of a page to another entity than the page-table
 618          * owner, whose id is 0.
 619          */
 620         return !!pte;
 621 }
 622
 623 static void stage2_put_pte(kvm_pte_t *ptep, struct kvm_s2_mmu *mmu, u64 addr,
 624                            u32 level, struct kvm_pgtable_mm_ops *mm_ops)
 625 {
 626         /*
 627          * Clear the existing PTE, and perform break-before-make with
 628          * TLB maintenance if it was valid.
 629          */
 630         if (kvm_pte_valid(*ptep)) {
 631                 kvm_clear_pte(ptep);
 632                 kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu, addr, level);
 633         }
 634
 635         mm_ops->put_page(ptep);
 636 }
 637
 638 static bool stage2_pte_cacheable(struct kvm_pgtable *pgt, kvm_pte_t pte)
 639 {
 640         u64 memattr = pte & KVM_PTE_LEAF_ATTR_LO_S2_MEMATTR;
 641         return memattr == KVM_S2_MEMATTR(pgt, NORMAL);
 642 }
 643
 644 static bool stage2_pte_executable(kvm_pte_t pte)
 645 {
 646         return !(pte & KVM_PTE_LEAF_ATTR_HI_S2_XN);
 647 }
 648
 649 static bool stage2_leaf_mapping_allowed(u64 addr, u64 end, u32 level,
 650                                         struct stage2_map_data *data)
 651 {
 652         if (data->force_pte && (level < (KVM_PGTABLE_MAX_LEVELS - 1)))
 653                 return false;
 654
 655         return kvm_block_mapping_supported(addr, end, data->phys, level);
 656 }
 657
 658 static int stage2_map_walker_try_leaf(u64 addr, u64 end, u32 level,
 659                                       kvm_pte_t *ptep,
 660                                       struct stage2_map_data *data)
 661 {
 662         kvm_pte_t new, old = *ptep;
 663         u64 granule = kvm_granule_size(level), phys = data->phys;
 664         struct kvm_pgtable *pgt = data->mmu->pgt;
 665         struct kvm_pgtable_mm_ops *mm_ops = data->mm_ops;
 666
 667         if (!stage2_leaf_mapping_allowed(addr, end, level, data))
 668                 return -E2BIG;
 669
 670         if (kvm_phys_is_valid(phys))
 671                 new = kvm_init_valid_leaf_pte(phys, data->attr, level);
 672         else
 673                 new = kvm_init_invalid_leaf_owner(data->owner_id);
 674
 675         if (stage2_pte_is_counted(old)) {
 676                 /*
 677                  * Skip updating the PTE if we are trying to recreate the exact
 678                  * same mapping or only change the access permissions. Instead,
 679                  * the vCPU will exit one more time from guest if still needed
 680                  * and then go through the path of relaxing permissions.
 681                  */
 682                 if (!stage2_pte_needs_update(old, new))
 683                         return -EAGAIN;
 684
 685                 stage2_put_pte(ptep, data->mmu, addr, level, mm_ops);
 686         }
 687
 688         /* Perform CMOs before installation of the guest stage-2 PTE */
 689         if (mm_ops->dcache_clean_inval_poc && stage2_pte_cacheable(pgt, new))
 690                 mm_ops->dcache_clean_inval_poc(kvm_pte_follow(new, mm_ops),
 691                                                 granule);
 692
 693         if (mm_ops->icache_inval_pou && stage2_pte_executable(new))
 694                 mm_ops->icache_inval_pou(kvm_pte_follow(new, mm_ops), granule);
 695
 696         smp_store_release(ptep, new);
 697         if (stage2_pte_is_counted(new))
 698                 mm_ops->get_page(ptep);
 699         if (kvm_phys_is_valid(phys))
 700                 data->phys += granule;
 701         return 0;
 702 }
 703
 704 static int stage2_map_walk_table_pre(u64 addr, u64 end, u32 level,
 705                                      kvm_pte_t *ptep,
 706                                      struct stage2_map_data *data)
 707 {
 708         if (data->anchor)
 709                 return 0;
 710
 711         if (!stage2_leaf_mapping_allowed(addr, end, level, data))
 712                 return 0;
 713
 714         data->childp = kvm_pte_follow(*ptep, data->mm_ops);
 715         kvm_clear_pte(ptep);
 716
 717         /*
 718          * Invalidate the whole stage-2, as we may have numerous leaf
 719          * entries below us which would otherwise need invalidating
 720          * individually.
 721          */
 722         kvm_call_hyp(__kvm_tlb_flush_vmid, data->mmu);
 723         data->anchor = ptep;
 724         return 0;
 725 }
 726
 727 static int stage2_map_walk_leaf(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
 728                                 struct stage2_map_data *data)
 729 {
 730         struct kvm_pgtable_mm_ops *mm_ops = data->mm_ops;
 731         kvm_pte_t *childp, pte = *ptep;
 732         int ret;
 733
 734         if (data->anchor) {
 735                 if (stage2_pte_is_counted(pte))
 736                         mm_ops->put_page(ptep);
 737
 738                 return 0;
 739         }
 740
 741         ret = stage2_map_walker_try_leaf(addr, end, level, ptep, data);
 742         if (ret != -E2BIG)
 743                 return ret;
 744
 745         if (WARN_ON(level == KVM_PGTABLE_MAX_LEVELS - 1))
 746                 return -EINVAL;
 747
 748         if (!data->memcache)
 749                 return -ENOMEM;
 750
 751         childp = mm_ops->zalloc_page(data->memcache);
 752         if (!childp)
 753                 return -ENOMEM;
 754
 755         /*
 756          * If we've run into an existing block mapping then replace it with
 757          * a table. Accesses beyond 'end' that fall within the new table
 758          * will be mapped lazily.
 759          */
 760         if (stage2_pte_is_counted(pte))
 761                 stage2_put_pte(ptep, data->mmu, addr, level, mm_ops);
 762
 763         kvm_set_table_pte(ptep, childp, mm_ops);
 764         mm_ops->get_page(ptep);
 765
 766         return 0;
 767 }
 768
 769 static int stage2_map_walk_table_post(u64 addr, u64 end, u32 level,
 770                                       kvm_pte_t *ptep,
 771                                       struct stage2_map_data *data)
 772 {
 773         struct kvm_pgtable_mm_ops *mm_ops = data->mm_ops;
 774         kvm_pte_t *childp;
 775         int ret = 0;
 776
 777         if (!data->anchor)
 778                 return 0;
 779
 780         if (data->anchor == ptep) {
 781                 childp = data->childp;
 782                 data->anchor = NULL;
 783                 data->childp = NULL;
 784                 ret = stage2_map_walk_leaf(addr, end, level, ptep, data);
 785         } else {
 786                 childp = kvm_pte_follow(*ptep, mm_ops);
 787         }
 788
 789         mm_ops->put_page(childp);
 790         mm_ops->put_page(ptep);
 791
 792         return ret;
 793 }
 794
 795 /*
 796  * This is a little fiddly, as we use all three of the walk flags. The idea
 797  * is that the TABLE_PRE callback runs for table entries on the way down,
 798  * looking for table entries which we could conceivably replace with a
 799  * block entry for this mapping. If it finds one, then it sets the 'anchor'
 800  * field in 'struct stage2_map_data' to point at the table entry, before
 801  * clearing the entry to zero and descending into the now detached table.
 802  *
 803  * The behaviour of the LEAF callback then depends on whether or not the
 804  * anchor has been set. If not, then we're not using a block mapping higher
 805  * up the table and we perform the mapping at the existing leaves instead.
 806  * If, on the other hand, the anchor _is_ set, then we drop references to
 807  * all valid leaves so that the pages beneath the anchor can be freed.
 808  *
 809  * Finally, the TABLE_POST callback does nothing if the anchor has not
 810  * been set, but otherwise frees the page-table pages while walking back up
 811  * the page-table, installing the block entry when it revisits the anchor
 812  * pointer and clearing the anchor to NULL.
 813  */
 814 static int stage2_map_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
 815                              enum kvm_pgtable_walk_flags flag, void * const arg)
 816 {
 817         struct stage2_map_data *data = arg;
 818
 819         switch (flag) {
 820         case KVM_PGTABLE_WALK_TABLE_PRE:
 821                 return stage2_map_walk_table_pre(addr, end, level, ptep, data);
 822         case KVM_PGTABLE_WALK_LEAF:
 823                 return stage2_map_walk_leaf(addr, end, level, ptep, data);
 824         case KVM_PGTABLE_WALK_TABLE_POST:
 825                 return stage2_map_walk_table_post(addr, end, level, ptep, data);
 826         }
 827
 828         return -EINVAL;
 829 }
 830
 831 int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
 832                            u64 phys, enum kvm_pgtable_prot prot,
 833                            void *mc)
 834 {
 835         int ret;
 836         struct stage2_map_data map_data = {
 837                 .phys           = ALIGN_DOWN(phys, PAGE_SIZE),
 838                 .mmu            = pgt->mmu,
 839                 .memcache       = mc,
 840                 .mm_ops         = pgt->mm_ops,
 841                 .force_pte      = pgt->force_pte_cb && pgt->force_pte_cb(addr, addr + size, prot),
 842         };
 843         struct kvm_pgtable_walker walker = {
 844                 .cb             = stage2_map_walker,
 845                 .flags          = KVM_PGTABLE_WALK_TABLE_PRE |
 846                                   KVM_PGTABLE_WALK_LEAF |
 847                                   KVM_PGTABLE_WALK_TABLE_POST,
 848                 .arg            = &map_data,
 849         };
 850
 851         if (WARN_ON((pgt->flags & KVM_PGTABLE_S2_IDMAP) && (addr != phys)))
 852                 return -EINVAL;
 853
 854         ret = stage2_set_prot_attr(pgt, prot, &map_data.attr);
 855         if (ret)
 856                 return ret;
 857
 858         ret = kvm_pgtable_walk(pgt, addr, size, &walker);
 859         dsb(ishst);
 860         return ret;
 861 }
 862
 863 int kvm_pgtable_stage2_set_owner(struct kvm_pgtable *pgt, u64 addr, u64 size,
 864                                  void *mc, u8 owner_id)
 865 {
 866         int ret;
 867         struct stage2_map_data map_data = {
 868                 .phys           = KVM_PHYS_INVALID,
 869                 .mmu            = pgt->mmu,
 870                 .memcache       = mc,
 871                 .mm_ops         = pgt->mm_ops,
 872                 .owner_id       = owner_id,
 873                 .force_pte      = true,
 874         };
 875         struct kvm_pgtable_walker walker = {
 876                 .cb             = stage2_map_walker,
 877                 .flags          = KVM_PGTABLE_WALK_TABLE_PRE |
 878                                   KVM_PGTABLE_WALK_LEAF |
 879                                   KVM_PGTABLE_WALK_TABLE_POST,
 880                 .arg            = &map_data,
 881         };
 882
 883         if (owner_id > KVM_MAX_OWNER_ID)
 884                 return -EINVAL;
 885
 886         ret = kvm_pgtable_walk(pgt, addr, size, &walker);
 887         return ret;
 888 }
 889
 890 static int stage2_unmap_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
 891                                enum kvm_pgtable_walk_flags flag,
 892                                void * const arg)
 893 {
 894         struct kvm_pgtable *pgt = arg;
 895         struct kvm_s2_mmu *mmu = pgt->mmu;
 896         struct kvm_pgtable_mm_ops *mm_ops = pgt->mm_ops;
 897         kvm_pte_t pte = *ptep, *childp = NULL;
 898         bool need_flush = false;
 899
 900         if (!kvm_pte_valid(pte)) {
 901                 if (stage2_pte_is_counted(pte)) {
 902                         kvm_clear_pte(ptep);
 903                         mm_ops->put_page(ptep);
 904                 }
 905                 return 0;
 906         }
 907
 908         if (kvm_pte_table(pte, level)) {
 909                 childp = kvm_pte_follow(pte, mm_ops);
 910
 911                 if (mm_ops->page_count(childp) != 1)
 912                         return 0;
 913         } else if (stage2_pte_cacheable(pgt, pte)) {
 914                 need_flush = !stage2_has_fwb(pgt);
 915         }
 916
 917         /*
 918          * This is similar to the map() path in that we unmap the entire
 919          * block entry and rely on the remaining portions being faulted
 920          * back lazily.
 921          */
 922         stage2_put_pte(ptep, mmu, addr, level, mm_ops);
 923
 924         if (need_flush) {
 925                 kvm_pte_t *pte_follow = kvm_pte_follow(pte, mm_ops);
 926
 927                 dcache_clean_inval_poc((unsigned long)pte_follow,
 928                                     (unsigned long)pte_follow +
 929                                             kvm_granule_size(level));
 930         }
 931
 932         if (childp)
 933                 mm_ops->put_page(childp);
 934
 935         return 0;
 936 }
 937
 938 int kvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size)
 939 {
 940         struct kvm_pgtable_walker walker = {
 941                 .cb     = stage2_unmap_walker,
 942                 .arg    = pgt,
 943                 .flags  = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST,
 944         };
 945
 946         return kvm_pgtable_walk(pgt, addr, size, &walker);
 947 }
 948
 949 struct stage2_attr_data {
 950         kvm_pte_t                       attr_set;
 951         kvm_pte_t                       attr_clr;
 952         kvm_pte_t                       pte;
 953         u32                             level;
 954         struct kvm_pgtable_mm_ops       *mm_ops;
 955 };
 956
 957 static int stage2_attr_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
 958                               enum kvm_pgtable_walk_flags flag,
 959                               void * const arg)
 960 {
 961         kvm_pte_t pte = *ptep;
 962         struct stage2_attr_data *data = arg;
 963         struct kvm_pgtable_mm_ops *mm_ops = data->mm_ops;
 964
 965         if (!kvm_pte_valid(pte))
 966                 return 0;
 967
 968         data->level = level;
 969         data->pte = pte;
 970         pte &= ~data->attr_clr;
 971         pte |= data->attr_set;
 972
 973         /*
 974          * We may race with the CPU trying to set the access flag here,
 975          * but worst-case the access flag update gets lost and will be
 976          * set on the next access instead.
 977          */
 978         if (data->pte != pte) {
 979                 /*
 980                  * Invalidate instruction cache before updating the guest
 981                  * stage-2 PTE if we are going to add executable permission.
 982                  */
 983                 if (mm_ops->icache_inval_pou &&
 984                     stage2_pte_executable(pte) && !stage2_pte_executable(*ptep))
 985                         mm_ops->icache_inval_pou(kvm_pte_follow(pte, mm_ops),
 986                                                   kvm_granule_size(level));
 987                 WRITE_ONCE(*ptep, pte);
 988         }
 989
 990         return 0;
 991 }
 992
 993 static int stage2_update_leaf_attrs(struct kvm_pgtable *pgt, u64 addr,
 994                                     u64 size, kvm_pte_t attr_set,
 995                                     kvm_pte_t attr_clr, kvm_pte_t *orig_pte,
 996                                     u32 *level)
 997 {
 998         int ret;
 999         kvm_pte_t attr_mask = KVM_PTE_LEAF_ATTR_LO | KVM_PTE_LEAF_ATTR_HI;
1000         struct stage2_attr_data data = {
1001                 .attr_set       = attr_set & attr_mask,
1002                 .attr_clr       = attr_clr & attr_mask,
1003                 .mm_ops         = pgt->mm_ops,
1004         };
1005         struct kvm_pgtable_walker walker = {
1006                 .cb             = stage2_attr_walker,
1007                 .arg            = &data,
1008                 .flags          = KVM_PGTABLE_WALK_LEAF,
1009         };
1010
1011         ret = kvm_pgtable_walk(pgt, addr, size, &walker);
1012         if (ret)
1013                 return ret;
1014
1015         if (orig_pte)
1016                 *orig_pte = data.pte;
1017
1018         if (level)
1019                 *level = data.level;
1020         return 0;
1021 }
1022
1023 int kvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size)
1024 {
1025         return stage2_update_leaf_attrs(pgt, addr, size, 0,
1026                                         KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W,
1027                                         NULL, NULL);
1028 }
1029
1030 kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr)
1031 {
1032         kvm_pte_t pte = 0;
1033         stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0,
1034                                  &pte, NULL);
1035         dsb(ishst);
1036         return pte;
1037 }
1038
1039 kvm_pte_t kvm_pgtable_stage2_mkold(struct kvm_pgtable *pgt, u64 addr)
1040 {
1041         kvm_pte_t pte = 0;
1042         stage2_update_leaf_attrs(pgt, addr, 1, 0, KVM_PTE_LEAF_ATTR_LO_S2_AF,
1043                                  &pte, NULL);
1044         /*
1045          * "But where's the TLBI?!", you scream.
1046          * "Over in the core code", I sigh.
1047          *
1048          * See the '->clear_flush_young()' callback on the KVM mmu notifier.
1049          */
1050         return pte;
1051 }
1052
1053 bool kvm_pgtable_stage2_is_young(struct kvm_pgtable *pgt, u64 addr)
1054 {
1055         kvm_pte_t pte = 0;
1056         stage2_update_leaf_attrs(pgt, addr, 1, 0, 0, &pte, NULL);
1057         return pte & KVM_PTE_LEAF_ATTR_LO_S2_AF;
1058 }
1059
1060 int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr,
1061                                    enum kvm_pgtable_prot prot)
1062 {
1063         int ret;
1064         u32 level;
1065         kvm_pte_t set = 0, clr = 0;
1066
1067         if (prot & KVM_PTE_LEAF_ATTR_HI_SW)
1068                 return -EINVAL;
1069
1070         if (prot & KVM_PGTABLE_PROT_R)
1071                 set |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R;
1072
1073         if (prot & KVM_PGTABLE_PROT_W)
1074                 set |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W;
1075
1076         if (prot & KVM_PGTABLE_PROT_X)
1077                 clr |= KVM_PTE_LEAF_ATTR_HI_S2_XN;
1078
1079         ret = stage2_update_leaf_attrs(pgt, addr, 1, set, clr, NULL, &level);
1080         if (!ret)
1081                 kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, pgt->mmu, addr, level);
1082         return ret;
1083 }
1084
1085 static int stage2_flush_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
1086                                enum kvm_pgtable_walk_flags flag,
1087                                void * const arg)
1088 {
1089         struct kvm_pgtable *pgt = arg;
1090         struct kvm_pgtable_mm_ops *mm_ops = pgt->mm_ops;
1091         kvm_pte_t pte = *ptep;
1092         kvm_pte_t *pte_follow;
1093
1094         if (!kvm_pte_valid(pte) || !stage2_pte_cacheable(pgt, pte))
1095                 return 0;
1096
1097         pte_follow = kvm_pte_follow(pte, mm_ops);
1098         dcache_clean_inval_poc((unsigned long)pte_follow,
1099                             (unsigned long)pte_follow +
1100                                     kvm_granule_size(level));
1101         return 0;
1102 }
1103
1104 int kvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size)
1105 {
1106         struct kvm_pgtable_walker walker = {
1107                 .cb     = stage2_flush_walker,
1108                 .flags  = KVM_PGTABLE_WALK_LEAF,
1109                 .arg    = pgt,
1110         };
1111
1112         if (stage2_has_fwb(pgt))
1113                 return 0;
1114
1115         return kvm_pgtable_walk(pgt, addr, size, &walker);
1116 }
1117
1118
1119 int __kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_arch *arch,
1120                               struct kvm_pgtable_mm_ops *mm_ops,
1121                               enum kvm_pgtable_stage2_flags flags,
1122                               kvm_pgtable_force_pte_cb_t force_pte_cb)
1123 {
1124         size_t pgd_sz;
1125         u64 vtcr = arch->vtcr;
1126         u32 ia_bits = VTCR_EL2_IPA(vtcr);
1127         u32 sl0 = FIELD_GET(VTCR_EL2_SL0_MASK, vtcr);
1128         u32 start_level = VTCR_EL2_TGRAN_SL0_BASE - sl0;
1129
1130         pgd_sz = kvm_pgd_pages(ia_bits, start_level) * PAGE_SIZE;
1131         pgt->pgd = mm_ops->zalloc_pages_exact(pgd_sz);
1132         if (!pgt->pgd)
1133                 return -ENOMEM;
1134
1135         pgt->ia_bits            = ia_bits;
1136         pgt->start_level        = start_level;
1137         pgt->mm_ops             = mm_ops;
1138         pgt->mmu                = &arch->mmu;
1139         pgt->flags              = flags;
1140         pgt->force_pte_cb       = force_pte_cb;
1141
1142         /* Ensure zeroed PGD pages are visible to the hardware walker */
1143         dsb(ishst);
1144         return 0;
1145 }
1146
1147 static int stage2_free_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
1148                               enum kvm_pgtable_walk_flags flag,
1149                               void * const arg)
1150 {
1151         struct kvm_pgtable_mm_ops *mm_ops = arg;
1152         kvm_pte_t pte = *ptep;
1153
1154         if (!stage2_pte_is_counted(pte))
1155                 return 0;
1156
1157         mm_ops->put_page(ptep);
1158
1159         if (kvm_pte_table(pte, level))
1160                 mm_ops->put_page(kvm_pte_follow(pte, mm_ops));
1161
1162         return 0;
1163 }
1164
1165 void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt)
1166 {
1167         size_t pgd_sz;
1168         struct kvm_pgtable_walker walker = {
1169                 .cb     = stage2_free_walker,
1170                 .flags  = KVM_PGTABLE_WALK_LEAF |
1171                           KVM_PGTABLE_WALK_TABLE_POST,
1172                 .arg    = pgt->mm_ops,
1173         };
1174
1175         WARN_ON(kvm_pgtable_walk(pgt, 0, BIT(pgt->ia_bits), &walker));
1176         pgd_sz = kvm_pgd_pages(pgt->ia_bits, pgt->start_level) * PAGE_SIZE;
1177         pgt->mm_ops->free_pages_exact(pgt->pgd, pgd_sz);
1178         pgt->pgd = NULL;
1179 }