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 #define KVM_PTE_VALID BIT(0) 15 16 #define KVM_PTE_TYPE BIT(1) 17 #define KVM_PTE_TYPE_BLOCK 0 18 #define KVM_PTE_TYPE_PAGE 1 19 #define KVM_PTE_TYPE_TABLE 1 20 21 #define KVM_PTE_ADDR_MASK GENMASK(47, PAGE_SHIFT) 22 #define KVM_PTE_ADDR_51_48 GENMASK(15, 12) 23 24 #define KVM_PTE_LEAF_ATTR_LO GENMASK(11, 2) 25 26 #define KVM_PTE_LEAF_ATTR_LO_S1_ATTRIDX GENMASK(4, 2) 27 #define KVM_PTE_LEAF_ATTR_LO_S1_AP GENMASK(7, 6) 28 #define KVM_PTE_LEAF_ATTR_LO_S1_AP_RO 3 29 #define KVM_PTE_LEAF_ATTR_LO_S1_AP_RW 1 30 #define KVM_PTE_LEAF_ATTR_LO_S1_SH GENMASK(9, 8) 31 #define KVM_PTE_LEAF_ATTR_LO_S1_SH_IS 3 32 #define KVM_PTE_LEAF_ATTR_LO_S1_AF BIT(10) 33 34 #define KVM_PTE_LEAF_ATTR_LO_S2_MEMATTR GENMASK(5, 2) 35 #define KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R BIT(6) 36 #define KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W BIT(7) 37 #define KVM_PTE_LEAF_ATTR_LO_S2_SH GENMASK(9, 8) 38 #define KVM_PTE_LEAF_ATTR_LO_S2_SH_IS 3 39 #define KVM_PTE_LEAF_ATTR_LO_S2_AF BIT(10) 40 41 #define KVM_PTE_LEAF_ATTR_HI GENMASK(63, 51) 42 43 #define KVM_PTE_LEAF_ATTR_HI_S1_XN BIT(54) 44 45 #define KVM_PTE_LEAF_ATTR_HI_S2_XN BIT(54) 46 47 #define KVM_PTE_LEAF_ATTR_S2_PERMS (KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | \ 48 KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | \ 49 KVM_PTE_LEAF_ATTR_HI_S2_XN) 50 51 #define KVM_PTE_LEAF_ATTR_S2_IGNORED GENMASK(58, 55) 52 53 #define KVM_INVALID_PTE_OWNER_MASK GENMASK(63, 56) 54 #define KVM_MAX_OWNER_ID 1 55 56 struct kvm_pgtable_walk_data { 57 struct kvm_pgtable *pgt; 58 struct kvm_pgtable_walker *walker; 59 60 u64 addr; 61 u64 end; 62 }; 63 64 static u64 kvm_granule_shift(u32 level) 65 { 66 /* Assumes KVM_PGTABLE_MAX_LEVELS is 4 */ 67 return ARM64_HW_PGTABLE_LEVEL_SHIFT(level); 68 } 69 70 static u64 kvm_granule_size(u32 level) 71 { 72 return BIT(kvm_granule_shift(level)); 73 } 74 75 #define KVM_PHYS_INVALID (-1ULL) 76 77 static bool kvm_phys_is_valid(u64 phys) 78 { 79 return phys < BIT(id_aa64mmfr0_parange_to_phys_shift(ID_AA64MMFR0_PARANGE_MAX)); 80 } 81 82 static bool kvm_level_supports_block_mapping(u32 level) 83 { 84 /* 85 * Reject invalid block mappings and don't bother with 4TB mappings for 86 * 52-bit PAs. 87 */ 88 return !(level == 0 || (PAGE_SIZE != SZ_4K && level == 1)); 89 } 90 91 static bool kvm_block_mapping_supported(u64 addr, u64 end, u64 phys, u32 level) 92 { 93 u64 granule = kvm_granule_size(level); 94 95 if (!kvm_level_supports_block_mapping(level)) 96 return false; 97 98 if (granule > (end - addr)) 99 return false; 100 101 if (kvm_phys_is_valid(phys) && !IS_ALIGNED(phys, granule)) 102 return false; 103 104 return IS_ALIGNED(addr, granule); 105 } 106 107 static u32 kvm_pgtable_idx(struct kvm_pgtable_walk_data *data, u32 level) 108 { 109 u64 shift = kvm_granule_shift(level); 110 u64 mask = BIT(PAGE_SHIFT - 3) - 1; 111 112 return (data->addr >> shift) & mask; 113 } 114 115 static u32 __kvm_pgd_page_idx(struct kvm_pgtable *pgt, u64 addr) 116 { 117 u64 shift = kvm_granule_shift(pgt->start_level - 1); /* May underflow */ 118 u64 mask = BIT(pgt->ia_bits) - 1; 119 120 return (addr & mask) >> shift; 121 } 122 123 static u32 kvm_pgd_page_idx(struct kvm_pgtable_walk_data *data) 124 { 125 return __kvm_pgd_page_idx(data->pgt, data->addr); 126 } 127 128 static u32 kvm_pgd_pages(u32 ia_bits, u32 start_level) 129 { 130 struct kvm_pgtable pgt = { 131 .ia_bits = ia_bits, 132 .start_level = start_level, 133 }; 134 135 return __kvm_pgd_page_idx(&pgt, -1ULL) + 1; 136 } 137 138 static bool kvm_pte_valid(kvm_pte_t pte) 139 { 140 return pte & KVM_PTE_VALID; 141 } 142 143 static bool kvm_pte_table(kvm_pte_t pte, u32 level) 144 { 145 if (level == KVM_PGTABLE_MAX_LEVELS - 1) 146 return false; 147 148 if (!kvm_pte_valid(pte)) 149 return false; 150 151 return FIELD_GET(KVM_PTE_TYPE, pte) == KVM_PTE_TYPE_TABLE; 152 } 153 154 static u64 kvm_pte_to_phys(kvm_pte_t pte) 155 { 156 u64 pa = pte & KVM_PTE_ADDR_MASK; 157 158 if (PAGE_SHIFT == 16) 159 pa |= FIELD_GET(KVM_PTE_ADDR_51_48, pte) << 48; 160 161 return pa; 162 } 163 164 static kvm_pte_t kvm_phys_to_pte(u64 pa) 165 { 166 kvm_pte_t pte = pa & KVM_PTE_ADDR_MASK; 167 168 if (PAGE_SHIFT == 16) 169 pte |= FIELD_PREP(KVM_PTE_ADDR_51_48, pa >> 48); 170 171 return pte; 172 } 173 174 static kvm_pte_t *kvm_pte_follow(kvm_pte_t pte, struct kvm_pgtable_mm_ops *mm_ops) 175 { 176 return mm_ops->phys_to_virt(kvm_pte_to_phys(pte)); 177 } 178 179 static void kvm_clear_pte(kvm_pte_t *ptep) 180 { 181 WRITE_ONCE(*ptep, 0); 182 } 183 184 static void kvm_set_table_pte(kvm_pte_t *ptep, kvm_pte_t *childp, 185 struct kvm_pgtable_mm_ops *mm_ops) 186 { 187 kvm_pte_t old = *ptep, pte = kvm_phys_to_pte(mm_ops->virt_to_phys(childp)); 188 189 pte |= FIELD_PREP(KVM_PTE_TYPE, KVM_PTE_TYPE_TABLE); 190 pte |= KVM_PTE_VALID; 191 192 WARN_ON(kvm_pte_valid(old)); 193 smp_store_release(ptep, pte); 194 } 195 196 static kvm_pte_t kvm_init_valid_leaf_pte(u64 pa, kvm_pte_t attr, u32 level) 197 { 198 kvm_pte_t pte = kvm_phys_to_pte(pa); 199 u64 type = (level == KVM_PGTABLE_MAX_LEVELS - 1) ? KVM_PTE_TYPE_PAGE : 200 KVM_PTE_TYPE_BLOCK; 201 202 pte |= attr & (KVM_PTE_LEAF_ATTR_LO | KVM_PTE_LEAF_ATTR_HI); 203 pte |= FIELD_PREP(KVM_PTE_TYPE, type); 204 pte |= KVM_PTE_VALID; 205 206 return pte; 207 } 208 209 static kvm_pte_t kvm_init_invalid_leaf_owner(u8 owner_id) 210 { 211 return FIELD_PREP(KVM_INVALID_PTE_OWNER_MASK, owner_id); 212 } 213 214 static int kvm_pgtable_visitor_cb(struct kvm_pgtable_walk_data *data, u64 addr, 215 u32 level, kvm_pte_t *ptep, 216 enum kvm_pgtable_walk_flags flag) 217 { 218 struct kvm_pgtable_walker *walker = data->walker; 219 return walker->cb(addr, data->end, level, ptep, flag, walker->arg); 220 } 221 222 static int __kvm_pgtable_walk(struct kvm_pgtable_walk_data *data, 223 kvm_pte_t *pgtable, u32 level); 224 225 static inline int __kvm_pgtable_visit(struct kvm_pgtable_walk_data *data, 226 kvm_pte_t *ptep, u32 level) 227 { 228 int ret = 0; 229 u64 addr = data->addr; 230 kvm_pte_t *childp, pte = *ptep; 231 bool table = kvm_pte_table(pte, level); 232 enum kvm_pgtable_walk_flags flags = data->walker->flags; 233 234 if (table && (flags & KVM_PGTABLE_WALK_TABLE_PRE)) { 235 ret = kvm_pgtable_visitor_cb(data, addr, level, ptep, 236 KVM_PGTABLE_WALK_TABLE_PRE); 237 } 238 239 if (!table && (flags & KVM_PGTABLE_WALK_LEAF)) { 240 ret = kvm_pgtable_visitor_cb(data, addr, level, ptep, 241 KVM_PGTABLE_WALK_LEAF); 242 pte = *ptep; 243 table = kvm_pte_table(pte, level); 244 } 245 246 if (ret) 247 goto out; 248 249 if (!table) { 250 data->addr = ALIGN_DOWN(data->addr, kvm_granule_size(level)); 251 data->addr += kvm_granule_size(level); 252 goto out; 253 } 254 255 childp = kvm_pte_follow(pte, data->pgt->mm_ops); 256 ret = __kvm_pgtable_walk(data, childp, level + 1); 257 if (ret) 258 goto out; 259 260 if (flags & KVM_PGTABLE_WALK_TABLE_POST) { 261 ret = kvm_pgtable_visitor_cb(data, addr, level, ptep, 262 KVM_PGTABLE_WALK_TABLE_POST); 263 } 264 265 out: 266 return ret; 267 } 268 269 static int __kvm_pgtable_walk(struct kvm_pgtable_walk_data *data, 270 kvm_pte_t *pgtable, u32 level) 271 { 272 u32 idx; 273 int ret = 0; 274 275 if (WARN_ON_ONCE(level >= KVM_PGTABLE_MAX_LEVELS)) 276 return -EINVAL; 277 278 for (idx = kvm_pgtable_idx(data, level); idx < PTRS_PER_PTE; ++idx) { 279 kvm_pte_t *ptep = &pgtable[idx]; 280 281 if (data->addr >= data->end) 282 break; 283 284 ret = __kvm_pgtable_visit(data, ptep, level); 285 if (ret) 286 break; 287 } 288 289 return ret; 290 } 291 292 static int _kvm_pgtable_walk(struct kvm_pgtable_walk_data *data) 293 { 294 u32 idx; 295 int ret = 0; 296 struct kvm_pgtable *pgt = data->pgt; 297 u64 limit = BIT(pgt->ia_bits); 298 299 if (data->addr > limit || data->end > limit) 300 return -ERANGE; 301 302 if (!pgt->pgd) 303 return -EINVAL; 304 305 for (idx = kvm_pgd_page_idx(data); data->addr < data->end; ++idx) { 306 kvm_pte_t *ptep = &pgt->pgd[idx * PTRS_PER_PTE]; 307 308 ret = __kvm_pgtable_walk(data, ptep, pgt->start_level); 309 if (ret) 310 break; 311 } 312 313 return ret; 314 } 315 316 int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size, 317 struct kvm_pgtable_walker *walker) 318 { 319 struct kvm_pgtable_walk_data walk_data = { 320 .pgt = pgt, 321 .addr = ALIGN_DOWN(addr, PAGE_SIZE), 322 .end = PAGE_ALIGN(walk_data.addr + size), 323 .walker = walker, 324 }; 325 326 return _kvm_pgtable_walk(&walk_data); 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 *ptep = attr; 361 362 return 0; 363 } 364 365 static bool hyp_map_walker_try_leaf(u64 addr, u64 end, u32 level, 366 kvm_pte_t *ptep, struct hyp_map_data *data) 367 { 368 kvm_pte_t new, old = *ptep; 369 u64 granule = kvm_granule_size(level), phys = data->phys; 370 371 if (!kvm_block_mapping_supported(addr, end, phys, level)) 372 return false; 373 374 /* Tolerate KVM recreating the exact same mapping */ 375 new = kvm_init_valid_leaf_pte(phys, data->attr, level); 376 if (old != new && !WARN_ON(kvm_pte_valid(old))) 377 smp_store_release(ptep, new); 378 379 data->phys += granule; 380 return true; 381 } 382 383 static int hyp_map_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, 384 enum kvm_pgtable_walk_flags flag, void * const arg) 385 { 386 kvm_pte_t *childp; 387 struct hyp_map_data *data = arg; 388 struct kvm_pgtable_mm_ops *mm_ops = data->mm_ops; 389 390 if (hyp_map_walker_try_leaf(addr, end, level, ptep, arg)) 391 return 0; 392 393 if (WARN_ON(level == KVM_PGTABLE_MAX_LEVELS - 1)) 394 return -EINVAL; 395 396 childp = (kvm_pte_t *)mm_ops->zalloc_page(NULL); 397 if (!childp) 398 return -ENOMEM; 399 400 kvm_set_table_pte(ptep, childp, mm_ops); 401 return 0; 402 } 403 404 int kvm_pgtable_hyp_map(struct kvm_pgtable *pgt, u64 addr, u64 size, u64 phys, 405 enum kvm_pgtable_prot prot) 406 { 407 int ret; 408 struct hyp_map_data map_data = { 409 .phys = ALIGN_DOWN(phys, PAGE_SIZE), 410 .mm_ops = pgt->mm_ops, 411 }; 412 struct kvm_pgtable_walker walker = { 413 .cb = hyp_map_walker, 414 .flags = KVM_PGTABLE_WALK_LEAF, 415 .arg = &map_data, 416 }; 417 418 ret = hyp_set_prot_attr(prot, &map_data.attr); 419 if (ret) 420 return ret; 421 422 ret = kvm_pgtable_walk(pgt, addr, size, &walker); 423 dsb(ishst); 424 isb(); 425 return ret; 426 } 427 428 int kvm_pgtable_hyp_init(struct kvm_pgtable *pgt, u32 va_bits, 429 struct kvm_pgtable_mm_ops *mm_ops) 430 { 431 u64 levels = ARM64_HW_PGTABLE_LEVELS(va_bits); 432 433 pgt->pgd = (kvm_pte_t *)mm_ops->zalloc_page(NULL); 434 if (!pgt->pgd) 435 return -ENOMEM; 436 437 pgt->ia_bits = va_bits; 438 pgt->start_level = KVM_PGTABLE_MAX_LEVELS - levels; 439 pgt->mm_ops = mm_ops; 440 pgt->mmu = NULL; 441 return 0; 442 } 443 444 static int hyp_free_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, 445 enum kvm_pgtable_walk_flags flag, void * const arg) 446 { 447 struct kvm_pgtable_mm_ops *mm_ops = arg; 448 449 mm_ops->put_page((void *)kvm_pte_follow(*ptep, mm_ops)); 450 return 0; 451 } 452 453 void kvm_pgtable_hyp_destroy(struct kvm_pgtable *pgt) 454 { 455 struct kvm_pgtable_walker walker = { 456 .cb = hyp_free_walker, 457 .flags = KVM_PGTABLE_WALK_TABLE_POST, 458 .arg = pgt->mm_ops, 459 }; 460 461 WARN_ON(kvm_pgtable_walk(pgt, 0, BIT(pgt->ia_bits), &walker)); 462 pgt->mm_ops->put_page(pgt->pgd); 463 pgt->pgd = NULL; 464 } 465 466 struct stage2_map_data { 467 u64 phys; 468 kvm_pte_t attr; 469 u8 owner_id; 470 471 kvm_pte_t *anchor; 472 kvm_pte_t *childp; 473 474 struct kvm_s2_mmu *mmu; 475 void *memcache; 476 477 struct kvm_pgtable_mm_ops *mm_ops; 478 }; 479 480 u64 kvm_get_vtcr(u64 mmfr0, u64 mmfr1, u32 phys_shift) 481 { 482 u64 vtcr = VTCR_EL2_FLAGS; 483 u8 lvls; 484 485 vtcr |= kvm_get_parange(mmfr0) << VTCR_EL2_PS_SHIFT; 486 vtcr |= VTCR_EL2_T0SZ(phys_shift); 487 /* 488 * Use a minimum 2 level page table to prevent splitting 489 * host PMD huge pages at stage2. 490 */ 491 lvls = stage2_pgtable_levels(phys_shift); 492 if (lvls < 2) 493 lvls = 2; 494 vtcr |= VTCR_EL2_LVLS_TO_SL0(lvls); 495 496 /* 497 * Enable the Hardware Access Flag management, unconditionally 498 * on all CPUs. The features is RES0 on CPUs without the support 499 * and must be ignored by the CPUs. 500 */ 501 vtcr |= VTCR_EL2_HA; 502 503 /* Set the vmid bits */ 504 vtcr |= (get_vmid_bits(mmfr1) == 16) ? 505 VTCR_EL2_VS_16BIT : 506 VTCR_EL2_VS_8BIT; 507 508 return vtcr; 509 } 510 511 static bool stage2_has_fwb(struct kvm_pgtable *pgt) 512 { 513 if (!cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) 514 return false; 515 516 return !(pgt->flags & KVM_PGTABLE_S2_NOFWB); 517 } 518 519 #define KVM_S2_MEMATTR(pgt, attr) PAGE_S2_MEMATTR(attr, stage2_has_fwb(pgt)) 520 521 static int stage2_set_prot_attr(struct kvm_pgtable *pgt, enum kvm_pgtable_prot prot, 522 kvm_pte_t *ptep) 523 { 524 bool device = prot & KVM_PGTABLE_PROT_DEVICE; 525 kvm_pte_t attr = device ? KVM_S2_MEMATTR(pgt, DEVICE_nGnRE) : 526 KVM_S2_MEMATTR(pgt, NORMAL); 527 u32 sh = KVM_PTE_LEAF_ATTR_LO_S2_SH_IS; 528 529 if (!(prot & KVM_PGTABLE_PROT_X)) 530 attr |= KVM_PTE_LEAF_ATTR_HI_S2_XN; 531 else if (device) 532 return -EINVAL; 533 534 if (prot & KVM_PGTABLE_PROT_R) 535 attr |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R; 536 537 if (prot & KVM_PGTABLE_PROT_W) 538 attr |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W; 539 540 attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S2_SH, sh); 541 attr |= KVM_PTE_LEAF_ATTR_LO_S2_AF; 542 *ptep = attr; 543 544 return 0; 545 } 546 547 static bool stage2_pte_needs_update(kvm_pte_t old, kvm_pte_t new) 548 { 549 if (!kvm_pte_valid(old) || !kvm_pte_valid(new)) 550 return true; 551 552 return ((old ^ new) & (~KVM_PTE_LEAF_ATTR_S2_PERMS)); 553 } 554 555 static bool stage2_pte_is_counted(kvm_pte_t pte) 556 { 557 /* 558 * The refcount tracks valid entries as well as invalid entries if they 559 * encode ownership of a page to another entity than the page-table 560 * owner, whose id is 0. 561 */ 562 return !!pte; 563 } 564 565 static void stage2_put_pte(kvm_pte_t *ptep, struct kvm_s2_mmu *mmu, u64 addr, 566 u32 level, struct kvm_pgtable_mm_ops *mm_ops) 567 { 568 /* 569 * Clear the existing PTE, and perform break-before-make with 570 * TLB maintenance if it was valid. 571 */ 572 if (kvm_pte_valid(*ptep)) { 573 kvm_clear_pte(ptep); 574 kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu, addr, level); 575 } 576 577 mm_ops->put_page(ptep); 578 } 579 580 static int stage2_map_walker_try_leaf(u64 addr, u64 end, u32 level, 581 kvm_pte_t *ptep, 582 struct stage2_map_data *data) 583 { 584 kvm_pte_t new, old = *ptep; 585 u64 granule = kvm_granule_size(level), phys = data->phys; 586 struct kvm_pgtable_mm_ops *mm_ops = data->mm_ops; 587 588 if (!kvm_block_mapping_supported(addr, end, phys, level)) 589 return -E2BIG; 590 591 if (kvm_phys_is_valid(phys)) 592 new = kvm_init_valid_leaf_pte(phys, data->attr, level); 593 else 594 new = kvm_init_invalid_leaf_owner(data->owner_id); 595 596 if (stage2_pte_is_counted(old)) { 597 /* 598 * Skip updating the PTE if we are trying to recreate the exact 599 * same mapping or only change the access permissions. Instead, 600 * the vCPU will exit one more time from guest if still needed 601 * and then go through the path of relaxing permissions. 602 */ 603 if (!stage2_pte_needs_update(old, new)) 604 return -EAGAIN; 605 606 stage2_put_pte(ptep, data->mmu, addr, level, mm_ops); 607 } 608 609 smp_store_release(ptep, new); 610 if (stage2_pte_is_counted(new)) 611 mm_ops->get_page(ptep); 612 if (kvm_phys_is_valid(phys)) 613 data->phys += granule; 614 return 0; 615 } 616 617 static int stage2_map_walk_table_pre(u64 addr, u64 end, u32 level, 618 kvm_pte_t *ptep, 619 struct stage2_map_data *data) 620 { 621 if (data->anchor) 622 return 0; 623 624 if (!kvm_block_mapping_supported(addr, end, data->phys, level)) 625 return 0; 626 627 data->childp = kvm_pte_follow(*ptep, data->mm_ops); 628 kvm_clear_pte(ptep); 629 630 /* 631 * Invalidate the whole stage-2, as we may have numerous leaf 632 * entries below us which would otherwise need invalidating 633 * individually. 634 */ 635 kvm_call_hyp(__kvm_tlb_flush_vmid, data->mmu); 636 data->anchor = ptep; 637 return 0; 638 } 639 640 static int stage2_map_walk_leaf(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, 641 struct stage2_map_data *data) 642 { 643 struct kvm_pgtable_mm_ops *mm_ops = data->mm_ops; 644 kvm_pte_t *childp, pte = *ptep; 645 int ret; 646 647 if (data->anchor) { 648 if (stage2_pte_is_counted(pte)) 649 mm_ops->put_page(ptep); 650 651 return 0; 652 } 653 654 ret = stage2_map_walker_try_leaf(addr, end, level, ptep, data); 655 if (ret != -E2BIG) 656 return ret; 657 658 if (WARN_ON(level == KVM_PGTABLE_MAX_LEVELS - 1)) 659 return -EINVAL; 660 661 if (!data->memcache) 662 return -ENOMEM; 663 664 childp = mm_ops->zalloc_page(data->memcache); 665 if (!childp) 666 return -ENOMEM; 667 668 /* 669 * If we've run into an existing block mapping then replace it with 670 * a table. Accesses beyond 'end' that fall within the new table 671 * will be mapped lazily. 672 */ 673 if (stage2_pte_is_counted(pte)) 674 stage2_put_pte(ptep, data->mmu, addr, level, mm_ops); 675 676 kvm_set_table_pte(ptep, childp, mm_ops); 677 mm_ops->get_page(ptep); 678 679 return 0; 680 } 681 682 static int stage2_map_walk_table_post(u64 addr, u64 end, u32 level, 683 kvm_pte_t *ptep, 684 struct stage2_map_data *data) 685 { 686 struct kvm_pgtable_mm_ops *mm_ops = data->mm_ops; 687 kvm_pte_t *childp; 688 int ret = 0; 689 690 if (!data->anchor) 691 return 0; 692 693 if (data->anchor == ptep) { 694 childp = data->childp; 695 data->anchor = NULL; 696 data->childp = NULL; 697 ret = stage2_map_walk_leaf(addr, end, level, ptep, data); 698 } else { 699 childp = kvm_pte_follow(*ptep, mm_ops); 700 } 701 702 mm_ops->put_page(childp); 703 mm_ops->put_page(ptep); 704 705 return ret; 706 } 707 708 /* 709 * This is a little fiddly, as we use all three of the walk flags. The idea 710 * is that the TABLE_PRE callback runs for table entries on the way down, 711 * looking for table entries which we could conceivably replace with a 712 * block entry for this mapping. If it finds one, then it sets the 'anchor' 713 * field in 'struct stage2_map_data' to point at the table entry, before 714 * clearing the entry to zero and descending into the now detached table. 715 * 716 * The behaviour of the LEAF callback then depends on whether or not the 717 * anchor has been set. If not, then we're not using a block mapping higher 718 * up the table and we perform the mapping at the existing leaves instead. 719 * If, on the other hand, the anchor _is_ set, then we drop references to 720 * all valid leaves so that the pages beneath the anchor can be freed. 721 * 722 * Finally, the TABLE_POST callback does nothing if the anchor has not 723 * been set, but otherwise frees the page-table pages while walking back up 724 * the page-table, installing the block entry when it revisits the anchor 725 * pointer and clearing the anchor to NULL. 726 */ 727 static int stage2_map_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, 728 enum kvm_pgtable_walk_flags flag, void * const arg) 729 { 730 struct stage2_map_data *data = arg; 731 732 switch (flag) { 733 case KVM_PGTABLE_WALK_TABLE_PRE: 734 return stage2_map_walk_table_pre(addr, end, level, ptep, data); 735 case KVM_PGTABLE_WALK_LEAF: 736 return stage2_map_walk_leaf(addr, end, level, ptep, data); 737 case KVM_PGTABLE_WALK_TABLE_POST: 738 return stage2_map_walk_table_post(addr, end, level, ptep, data); 739 } 740 741 return -EINVAL; 742 } 743 744 int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size, 745 u64 phys, enum kvm_pgtable_prot prot, 746 void *mc) 747 { 748 int ret; 749 struct stage2_map_data map_data = { 750 .phys = ALIGN_DOWN(phys, PAGE_SIZE), 751 .mmu = pgt->mmu, 752 .memcache = mc, 753 .mm_ops = pgt->mm_ops, 754 }; 755 struct kvm_pgtable_walker walker = { 756 .cb = stage2_map_walker, 757 .flags = KVM_PGTABLE_WALK_TABLE_PRE | 758 KVM_PGTABLE_WALK_LEAF | 759 KVM_PGTABLE_WALK_TABLE_POST, 760 .arg = &map_data, 761 }; 762 763 if (WARN_ON((pgt->flags & KVM_PGTABLE_S2_IDMAP) && (addr != phys))) 764 return -EINVAL; 765 766 ret = stage2_set_prot_attr(pgt, prot, &map_data.attr); 767 if (ret) 768 return ret; 769 770 ret = kvm_pgtable_walk(pgt, addr, size, &walker); 771 dsb(ishst); 772 return ret; 773 } 774 775 int kvm_pgtable_stage2_set_owner(struct kvm_pgtable *pgt, u64 addr, u64 size, 776 void *mc, u8 owner_id) 777 { 778 int ret; 779 struct stage2_map_data map_data = { 780 .phys = KVM_PHYS_INVALID, 781 .mmu = pgt->mmu, 782 .memcache = mc, 783 .mm_ops = pgt->mm_ops, 784 .owner_id = owner_id, 785 }; 786 struct kvm_pgtable_walker walker = { 787 .cb = stage2_map_walker, 788 .flags = KVM_PGTABLE_WALK_TABLE_PRE | 789 KVM_PGTABLE_WALK_LEAF | 790 KVM_PGTABLE_WALK_TABLE_POST, 791 .arg = &map_data, 792 }; 793 794 if (owner_id > KVM_MAX_OWNER_ID) 795 return -EINVAL; 796 797 ret = kvm_pgtable_walk(pgt, addr, size, &walker); 798 return ret; 799 } 800 801 static bool stage2_pte_cacheable(struct kvm_pgtable *pgt, kvm_pte_t pte) 802 { 803 u64 memattr = pte & KVM_PTE_LEAF_ATTR_LO_S2_MEMATTR; 804 return memattr == KVM_S2_MEMATTR(pgt, NORMAL); 805 } 806 807 static int stage2_unmap_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, 808 enum kvm_pgtable_walk_flags flag, 809 void * const arg) 810 { 811 struct kvm_pgtable *pgt = arg; 812 struct kvm_s2_mmu *mmu = pgt->mmu; 813 struct kvm_pgtable_mm_ops *mm_ops = pgt->mm_ops; 814 kvm_pte_t pte = *ptep, *childp = NULL; 815 bool need_flush = false; 816 817 if (!kvm_pte_valid(pte)) { 818 if (stage2_pte_is_counted(pte)) { 819 kvm_clear_pte(ptep); 820 mm_ops->put_page(ptep); 821 } 822 return 0; 823 } 824 825 if (kvm_pte_table(pte, level)) { 826 childp = kvm_pte_follow(pte, mm_ops); 827 828 if (mm_ops->page_count(childp) != 1) 829 return 0; 830 } else if (stage2_pte_cacheable(pgt, pte)) { 831 need_flush = !stage2_has_fwb(pgt); 832 } 833 834 /* 835 * This is similar to the map() path in that we unmap the entire 836 * block entry and rely on the remaining portions being faulted 837 * back lazily. 838 */ 839 stage2_put_pte(ptep, mmu, addr, level, mm_ops); 840 841 if (need_flush) { 842 __flush_dcache_area(kvm_pte_follow(pte, mm_ops), 843 kvm_granule_size(level)); 844 } 845 846 if (childp) 847 mm_ops->put_page(childp); 848 849 return 0; 850 } 851 852 int kvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size) 853 { 854 struct kvm_pgtable_walker walker = { 855 .cb = stage2_unmap_walker, 856 .arg = pgt, 857 .flags = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST, 858 }; 859 860 return kvm_pgtable_walk(pgt, addr, size, &walker); 861 } 862 863 struct stage2_attr_data { 864 kvm_pte_t attr_set; 865 kvm_pte_t attr_clr; 866 kvm_pte_t pte; 867 u32 level; 868 }; 869 870 static int stage2_attr_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, 871 enum kvm_pgtable_walk_flags flag, 872 void * const arg) 873 { 874 kvm_pte_t pte = *ptep; 875 struct stage2_attr_data *data = arg; 876 877 if (!kvm_pte_valid(pte)) 878 return 0; 879 880 data->level = level; 881 data->pte = pte; 882 pte &= ~data->attr_clr; 883 pte |= data->attr_set; 884 885 /* 886 * We may race with the CPU trying to set the access flag here, 887 * but worst-case the access flag update gets lost and will be 888 * set on the next access instead. 889 */ 890 if (data->pte != pte) 891 WRITE_ONCE(*ptep, pte); 892 893 return 0; 894 } 895 896 static int stage2_update_leaf_attrs(struct kvm_pgtable *pgt, u64 addr, 897 u64 size, kvm_pte_t attr_set, 898 kvm_pte_t attr_clr, kvm_pte_t *orig_pte, 899 u32 *level) 900 { 901 int ret; 902 kvm_pte_t attr_mask = KVM_PTE_LEAF_ATTR_LO | KVM_PTE_LEAF_ATTR_HI; 903 struct stage2_attr_data data = { 904 .attr_set = attr_set & attr_mask, 905 .attr_clr = attr_clr & attr_mask, 906 }; 907 struct kvm_pgtable_walker walker = { 908 .cb = stage2_attr_walker, 909 .arg = &data, 910 .flags = KVM_PGTABLE_WALK_LEAF, 911 }; 912 913 ret = kvm_pgtable_walk(pgt, addr, size, &walker); 914 if (ret) 915 return ret; 916 917 if (orig_pte) 918 *orig_pte = data.pte; 919 920 if (level) 921 *level = data.level; 922 return 0; 923 } 924 925 int kvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size) 926 { 927 return stage2_update_leaf_attrs(pgt, addr, size, 0, 928 KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W, 929 NULL, NULL); 930 } 931 932 kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr) 933 { 934 kvm_pte_t pte = 0; 935 stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0, 936 &pte, NULL); 937 dsb(ishst); 938 return pte; 939 } 940 941 kvm_pte_t kvm_pgtable_stage2_mkold(struct kvm_pgtable *pgt, u64 addr) 942 { 943 kvm_pte_t pte = 0; 944 stage2_update_leaf_attrs(pgt, addr, 1, 0, KVM_PTE_LEAF_ATTR_LO_S2_AF, 945 &pte, NULL); 946 /* 947 * "But where's the TLBI?!", you scream. 948 * "Over in the core code", I sigh. 949 * 950 * See the '->clear_flush_young()' callback on the KVM mmu notifier. 951 */ 952 return pte; 953 } 954 955 bool kvm_pgtable_stage2_is_young(struct kvm_pgtable *pgt, u64 addr) 956 { 957 kvm_pte_t pte = 0; 958 stage2_update_leaf_attrs(pgt, addr, 1, 0, 0, &pte, NULL); 959 return pte & KVM_PTE_LEAF_ATTR_LO_S2_AF; 960 } 961 962 int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr, 963 enum kvm_pgtable_prot prot) 964 { 965 int ret; 966 u32 level; 967 kvm_pte_t set = 0, clr = 0; 968 969 if (prot & KVM_PGTABLE_PROT_R) 970 set |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R; 971 972 if (prot & KVM_PGTABLE_PROT_W) 973 set |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W; 974 975 if (prot & KVM_PGTABLE_PROT_X) 976 clr |= KVM_PTE_LEAF_ATTR_HI_S2_XN; 977 978 ret = stage2_update_leaf_attrs(pgt, addr, 1, set, clr, NULL, &level); 979 if (!ret) 980 kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, pgt->mmu, addr, level); 981 return ret; 982 } 983 984 static int stage2_flush_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, 985 enum kvm_pgtable_walk_flags flag, 986 void * const arg) 987 { 988 struct kvm_pgtable *pgt = arg; 989 struct kvm_pgtable_mm_ops *mm_ops = pgt->mm_ops; 990 kvm_pte_t pte = *ptep; 991 992 if (!kvm_pte_valid(pte) || !stage2_pte_cacheable(pgt, pte)) 993 return 0; 994 995 __flush_dcache_area(kvm_pte_follow(pte, mm_ops), kvm_granule_size(level)); 996 return 0; 997 } 998 999 int kvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size) 1000 { 1001 struct kvm_pgtable_walker walker = { 1002 .cb = stage2_flush_walker, 1003 .flags = KVM_PGTABLE_WALK_LEAF, 1004 .arg = pgt, 1005 }; 1006 1007 if (stage2_has_fwb(pgt)) 1008 return 0; 1009 1010 return kvm_pgtable_walk(pgt, addr, size, &walker); 1011 } 1012 1013 int kvm_pgtable_stage2_init_flags(struct kvm_pgtable *pgt, struct kvm_arch *arch, 1014 struct kvm_pgtable_mm_ops *mm_ops, 1015 enum kvm_pgtable_stage2_flags flags) 1016 { 1017 size_t pgd_sz; 1018 u64 vtcr = arch->vtcr; 1019 u32 ia_bits = VTCR_EL2_IPA(vtcr); 1020 u32 sl0 = FIELD_GET(VTCR_EL2_SL0_MASK, vtcr); 1021 u32 start_level = VTCR_EL2_TGRAN_SL0_BASE - sl0; 1022 1023 pgd_sz = kvm_pgd_pages(ia_bits, start_level) * PAGE_SIZE; 1024 pgt->pgd = mm_ops->zalloc_pages_exact(pgd_sz); 1025 if (!pgt->pgd) 1026 return -ENOMEM; 1027 1028 pgt->ia_bits = ia_bits; 1029 pgt->start_level = start_level; 1030 pgt->mm_ops = mm_ops; 1031 pgt->mmu = &arch->mmu; 1032 pgt->flags = flags; 1033 1034 /* Ensure zeroed PGD pages are visible to the hardware walker */ 1035 dsb(ishst); 1036 return 0; 1037 } 1038 1039 static int stage2_free_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep, 1040 enum kvm_pgtable_walk_flags flag, 1041 void * const arg) 1042 { 1043 struct kvm_pgtable_mm_ops *mm_ops = arg; 1044 kvm_pte_t pte = *ptep; 1045 1046 if (!stage2_pte_is_counted(pte)) 1047 return 0; 1048 1049 mm_ops->put_page(ptep); 1050 1051 if (kvm_pte_table(pte, level)) 1052 mm_ops->put_page(kvm_pte_follow(pte, mm_ops)); 1053 1054 return 0; 1055 } 1056 1057 void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt) 1058 { 1059 size_t pgd_sz; 1060 struct kvm_pgtable_walker walker = { 1061 .cb = stage2_free_walker, 1062 .flags = KVM_PGTABLE_WALK_LEAF | 1063 KVM_PGTABLE_WALK_TABLE_POST, 1064 .arg = pgt->mm_ops, 1065 }; 1066 1067 WARN_ON(kvm_pgtable_walk(pgt, 0, BIT(pgt->ia_bits), &walker)); 1068 pgd_sz = kvm_pgd_pages(pgt->ia_bits, pgt->start_level) * PAGE_SIZE; 1069 pgt->mm_ops->free_pages_exact(pgt->pgd, pgd_sz); 1070 pgt->pgd = NULL; 1071 } 1072 1073 #define KVM_PTE_LEAF_S2_COMPAT_MASK (KVM_PTE_LEAF_ATTR_S2_PERMS | \ 1074 KVM_PTE_LEAF_ATTR_LO_S2_MEMATTR | \ 1075 KVM_PTE_LEAF_ATTR_S2_IGNORED) 1076 1077 static int stage2_check_permission_walker(u64 addr, u64 end, u32 level, 1078 kvm_pte_t *ptep, 1079 enum kvm_pgtable_walk_flags flag, 1080 void * const arg) 1081 { 1082 kvm_pte_t old_attr, pte = *ptep, *new_attr = arg; 1083 1084 /* 1085 * Compatible mappings are either invalid and owned by the page-table 1086 * owner (whose id is 0), or valid with matching permission attributes. 1087 */ 1088 if (kvm_pte_valid(pte)) { 1089 old_attr = pte & KVM_PTE_LEAF_S2_COMPAT_MASK; 1090 if (old_attr != *new_attr) 1091 return -EEXIST; 1092 } else if (pte) { 1093 return -EEXIST; 1094 } 1095 1096 return 0; 1097 } 1098 1099 int kvm_pgtable_stage2_find_range(struct kvm_pgtable *pgt, u64 addr, 1100 enum kvm_pgtable_prot prot, 1101 struct kvm_mem_range *range) 1102 { 1103 kvm_pte_t attr; 1104 struct kvm_pgtable_walker check_perm_walker = { 1105 .cb = stage2_check_permission_walker, 1106 .flags = KVM_PGTABLE_WALK_LEAF, 1107 .arg = &attr, 1108 }; 1109 u64 granule, start, end; 1110 u32 level; 1111 int ret; 1112 1113 ret = stage2_set_prot_attr(pgt, prot, &attr); 1114 if (ret) 1115 return ret; 1116 attr &= KVM_PTE_LEAF_S2_COMPAT_MASK; 1117 1118 for (level = pgt->start_level; level < KVM_PGTABLE_MAX_LEVELS; level++) { 1119 granule = kvm_granule_size(level); 1120 start = ALIGN_DOWN(addr, granule); 1121 end = start + granule; 1122 1123 if (!kvm_level_supports_block_mapping(level)) 1124 continue; 1125 1126 if (start < range->start || range->end < end) 1127 continue; 1128 1129 /* 1130 * Check the presence of existing mappings with incompatible 1131 * permissions within the current block range, and try one level 1132 * deeper if one is found. 1133 */ 1134 ret = kvm_pgtable_walk(pgt, start, granule, &check_perm_walker); 1135 if (ret != -EEXIST) 1136 break; 1137 } 1138 1139 if (!ret) { 1140 range->start = start; 1141 range->end = end; 1142 } 1143 1144 return ret; 1145 } 1146