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 \ 25 ({ cpus_have_final_cap(ARM64_KVM_HVHE) ? 2 : 3; }) 26#define KVM_PTE_LEAF_ATTR_LO_S1_AP_RW \ 27 ({ cpus_have_final_cap(ARM64_KVM_HVHE) ? 0 : 1; }) 28#define KVM_PTE_LEAF_ATTR_LO_S1_SH GENMASK(9, 8) 29#define KVM_PTE_LEAF_ATTR_LO_S1_SH_IS 3 30#define KVM_PTE_LEAF_ATTR_LO_S1_AF BIT(10) 31 32#define KVM_PTE_LEAF_ATTR_LO_S2_MEMATTR GENMASK(5, 2) 33#define KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R BIT(6) 34#define KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W BIT(7) 35#define KVM_PTE_LEAF_ATTR_LO_S2_SH GENMASK(9, 8) 36#define KVM_PTE_LEAF_ATTR_LO_S2_SH_IS 3 37#define KVM_PTE_LEAF_ATTR_LO_S2_AF BIT(10) 38 39#define KVM_PTE_LEAF_ATTR_HI GENMASK(63, 50) 40 41#define KVM_PTE_LEAF_ATTR_HI_SW GENMASK(58, 55) 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_HI_S1_GP BIT(50) 48 49#define KVM_PTE_LEAF_ATTR_S2_PERMS (KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R | \ 50 KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | \ 51 KVM_PTE_LEAF_ATTR_HI_S2_XN) 52 53#define KVM_INVALID_PTE_OWNER_MASK GENMASK(9, 2) 54#define KVM_MAX_OWNER_ID 1 55 56/* 57 * Used to indicate a pte for which a 'break-before-make' sequence is in 58 * progress. 59 */ 60#define KVM_INVALID_PTE_LOCKED BIT(10) 61 62struct kvm_pgtable_walk_data { 63 struct kvm_pgtable_walker *walker; 64 65 const u64 start; 66 u64 addr; 67 const u64 end; 68}; 69 70static bool kvm_pgtable_walk_skip_bbm_tlbi(const struct kvm_pgtable_visit_ctx *ctx) 71{ 72 return unlikely(ctx->flags & KVM_PGTABLE_WALK_SKIP_BBM_TLBI); 73} 74 75static bool kvm_pgtable_walk_skip_cmo(const struct kvm_pgtable_visit_ctx *ctx) 76{ 77 return unlikely(ctx->flags & KVM_PGTABLE_WALK_SKIP_CMO); 78} 79 80static bool kvm_phys_is_valid(u64 phys) 81{ 82 u64 parange_max = kvm_get_parange_max(); 83 u8 shift = id_aa64mmfr0_parange_to_phys_shift(parange_max); 84 85 return phys < BIT(shift); 86} 87 88static bool kvm_block_mapping_supported(const struct kvm_pgtable_visit_ctx *ctx, u64 phys) 89{ 90 u64 granule = kvm_granule_size(ctx->level); 91 92 if (!kvm_level_supports_block_mapping(ctx->level)) 93 return false; 94 95 if (granule > (ctx->end - ctx->addr)) 96 return false; 97 98 if (kvm_phys_is_valid(phys) && !IS_ALIGNED(phys, granule)) 99 return false; 100 101 return IS_ALIGNED(ctx->addr, granule); 102} 103 104static u32 kvm_pgtable_idx(struct kvm_pgtable_walk_data *data, s8 level) 105{ 106 u64 shift = kvm_granule_shift(level); 107 u64 mask = BIT(PAGE_SHIFT - 3) - 1; 108 109 return (data->addr >> shift) & mask; 110} 111 112static u32 kvm_pgd_page_idx(struct kvm_pgtable *pgt, u64 addr) 113{ 114 u64 shift = kvm_granule_shift(pgt->start_level - 1); /* May underflow */ 115 u64 mask = BIT(pgt->ia_bits) - 1; 116 117 return (addr & mask) >> shift; 118} 119 120static u32 kvm_pgd_pages(u32 ia_bits, s8 start_level) 121{ 122 struct kvm_pgtable pgt = { 123 .ia_bits = ia_bits, 124 .start_level = start_level, 125 }; 126 127 return kvm_pgd_page_idx(&pgt, -1ULL) + 1; 128} 129 130static bool kvm_pte_table(kvm_pte_t pte, s8 level) 131{ 132 if (level == KVM_PGTABLE_LAST_LEVEL) 133 return false; 134 135 if (!kvm_pte_valid(pte)) 136 return false; 137 138 return FIELD_GET(KVM_PTE_TYPE, pte) == KVM_PTE_TYPE_TABLE; 139} 140 141static kvm_pte_t *kvm_pte_follow(kvm_pte_t pte, struct kvm_pgtable_mm_ops *mm_ops) 142{ 143 return mm_ops->phys_to_virt(kvm_pte_to_phys(pte)); 144} 145 146static void kvm_clear_pte(kvm_pte_t *ptep) 147{ 148 WRITE_ONCE(*ptep, 0); 149} 150 151static kvm_pte_t kvm_init_table_pte(kvm_pte_t *childp, struct kvm_pgtable_mm_ops *mm_ops) 152{ 153 kvm_pte_t pte = kvm_phys_to_pte(mm_ops->virt_to_phys(childp)); 154 155 pte |= FIELD_PREP(KVM_PTE_TYPE, KVM_PTE_TYPE_TABLE); 156 pte |= KVM_PTE_VALID; 157 return pte; 158} 159 160static kvm_pte_t kvm_init_valid_leaf_pte(u64 pa, kvm_pte_t attr, s8 level) 161{ 162 kvm_pte_t pte = kvm_phys_to_pte(pa); 163 u64 type = (level == KVM_PGTABLE_LAST_LEVEL) ? KVM_PTE_TYPE_PAGE : 164 KVM_PTE_TYPE_BLOCK; 165 166 pte |= attr & (KVM_PTE_LEAF_ATTR_LO | KVM_PTE_LEAF_ATTR_HI); 167 pte |= FIELD_PREP(KVM_PTE_TYPE, type); 168 pte |= KVM_PTE_VALID; 169 170 return pte; 171} 172 173static kvm_pte_t kvm_init_invalid_leaf_owner(u8 owner_id) 174{ 175 return FIELD_PREP(KVM_INVALID_PTE_OWNER_MASK, owner_id); 176} 177 178static int kvm_pgtable_visitor_cb(struct kvm_pgtable_walk_data *data, 179 const struct kvm_pgtable_visit_ctx *ctx, 180 enum kvm_pgtable_walk_flags visit) 181{ 182 struct kvm_pgtable_walker *walker = data->walker; 183 184 /* Ensure the appropriate lock is held (e.g. RCU lock for stage-2 MMU) */ 185 WARN_ON_ONCE(kvm_pgtable_walk_shared(ctx) && !kvm_pgtable_walk_lock_held()); 186 return walker->cb(ctx, visit); 187} 188 189static bool kvm_pgtable_walk_continue(const struct kvm_pgtable_walker *walker, 190 int r) 191{ 192 /* 193 * Visitor callbacks return EAGAIN when the conditions that led to a 194 * fault are no longer reflected in the page tables due to a race to 195 * update a PTE. In the context of a fault handler this is interpreted 196 * as a signal to retry guest execution. 197 * 198 * Ignore the return code altogether for walkers outside a fault handler 199 * (e.g. write protecting a range of memory) and chug along with the 200 * page table walk. 201 */ 202 if (r == -EAGAIN) 203 return !(walker->flags & KVM_PGTABLE_WALK_HANDLE_FAULT); 204 205 return !r; 206} 207 208static int __kvm_pgtable_walk(struct kvm_pgtable_walk_data *data, 209 struct kvm_pgtable_mm_ops *mm_ops, kvm_pteref_t pgtable, s8 level); 210 211static inline int __kvm_pgtable_visit(struct kvm_pgtable_walk_data *data, 212 struct kvm_pgtable_mm_ops *mm_ops, 213 kvm_pteref_t pteref, s8 level) 214{ 215 enum kvm_pgtable_walk_flags flags = data->walker->flags; 216 kvm_pte_t *ptep = kvm_dereference_pteref(data->walker, pteref); 217 struct kvm_pgtable_visit_ctx ctx = { 218 .ptep = ptep, 219 .old = READ_ONCE(*ptep), 220 .arg = data->walker->arg, 221 .mm_ops = mm_ops, 222 .start = data->start, 223 .addr = data->addr, 224 .end = data->end, 225 .level = level, 226 .flags = flags, 227 }; 228 int ret = 0; 229 bool reload = false; 230 kvm_pteref_t childp; 231 bool table = kvm_pte_table(ctx.old, level); 232 233 if (table && (ctx.flags & KVM_PGTABLE_WALK_TABLE_PRE)) { 234 ret = kvm_pgtable_visitor_cb(data, &ctx, KVM_PGTABLE_WALK_TABLE_PRE); 235 reload = true; 236 } 237 238 if (!table && (ctx.flags & KVM_PGTABLE_WALK_LEAF)) { 239 ret = kvm_pgtable_visitor_cb(data, &ctx, KVM_PGTABLE_WALK_LEAF); 240 reload = true; 241 } 242 243 /* 244 * Reload the page table after invoking the walker callback for leaf 245 * entries or after pre-order traversal, to allow the walker to descend 246 * into a newly installed or replaced table. 247 */ 248 if (reload) { 249 ctx.old = READ_ONCE(*ptep); 250 table = kvm_pte_table(ctx.old, level); 251 } 252 253 if (!kvm_pgtable_walk_continue(data->walker, ret)) 254 goto out; 255 256 if (!table) { 257 data->addr = ALIGN_DOWN(data->addr, kvm_granule_size(level)); 258 data->addr += kvm_granule_size(level); 259 goto out; 260 } 261 262 childp = (kvm_pteref_t)kvm_pte_follow(ctx.old, mm_ops); 263 ret = __kvm_pgtable_walk(data, mm_ops, childp, level + 1); 264 if (!kvm_pgtable_walk_continue(data->walker, ret)) 265 goto out; 266 267 if (ctx.flags & KVM_PGTABLE_WALK_TABLE_POST) 268 ret = kvm_pgtable_visitor_cb(data, &ctx, KVM_PGTABLE_WALK_TABLE_POST); 269 270out: 271 if (kvm_pgtable_walk_continue(data->walker, ret)) 272 return 0; 273 274 return ret; 275} 276 277static int __kvm_pgtable_walk(struct kvm_pgtable_walk_data *data, 278 struct kvm_pgtable_mm_ops *mm_ops, kvm_pteref_t pgtable, s8 level) 279{ 280 u32 idx; 281 int ret = 0; 282 283 if (WARN_ON_ONCE(level < KVM_PGTABLE_FIRST_LEVEL || 284 level > KVM_PGTABLE_LAST_LEVEL)) 285 return -EINVAL; 286 287 for (idx = kvm_pgtable_idx(data, level); idx < PTRS_PER_PTE; ++idx) { 288 kvm_pteref_t pteref = &pgtable[idx]; 289 290 if (data->addr >= data->end) 291 break; 292 293 ret = __kvm_pgtable_visit(data, mm_ops, pteref, level); 294 if (ret) 295 break; 296 } 297 298 return ret; 299} 300 301static int _kvm_pgtable_walk(struct kvm_pgtable *pgt, struct kvm_pgtable_walk_data *data) 302{ 303 u32 idx; 304 int ret = 0; 305 u64 limit = BIT(pgt->ia_bits); 306 307 if (data->addr > limit || data->end > limit) 308 return -ERANGE; 309 310 if (!pgt->pgd) 311 return -EINVAL; 312 313 for (idx = kvm_pgd_page_idx(pgt, data->addr); data->addr < data->end; ++idx) { 314 kvm_pteref_t pteref = &pgt->pgd[idx * PTRS_PER_PTE]; 315 316 ret = __kvm_pgtable_walk(data, pgt->mm_ops, pteref, pgt->start_level); 317 if (ret) 318 break; 319 } 320 321 return ret; 322} 323 324int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size, 325 struct kvm_pgtable_walker *walker) 326{ 327 struct kvm_pgtable_walk_data walk_data = { 328 .start = ALIGN_DOWN(addr, PAGE_SIZE), 329 .addr = ALIGN_DOWN(addr, PAGE_SIZE), 330 .end = PAGE_ALIGN(walk_data.addr + size), 331 .walker = walker, 332 }; 333 int r; 334 335 r = kvm_pgtable_walk_begin(walker); 336 if (r) 337 return r; 338 339 r = _kvm_pgtable_walk(pgt, &walk_data); 340 kvm_pgtable_walk_end(walker); 341 342 return r; 343} 344 345struct leaf_walk_data { 346 kvm_pte_t pte; 347 s8 level; 348}; 349 350static int leaf_walker(const struct kvm_pgtable_visit_ctx *ctx, 351 enum kvm_pgtable_walk_flags visit) 352{ 353 struct leaf_walk_data *data = ctx->arg; 354 355 data->pte = ctx->old; 356 data->level = ctx->level; 357 358 return 0; 359} 360 361int kvm_pgtable_get_leaf(struct kvm_pgtable *pgt, u64 addr, 362 kvm_pte_t *ptep, s8 *level) 363{ 364 struct leaf_walk_data data; 365 struct kvm_pgtable_walker walker = { 366 .cb = leaf_walker, 367 .flags = KVM_PGTABLE_WALK_LEAF, 368 .arg = &data, 369 }; 370 int ret; 371 372 ret = kvm_pgtable_walk(pgt, ALIGN_DOWN(addr, PAGE_SIZE), 373 PAGE_SIZE, &walker); 374 if (!ret) { 375 if (ptep) 376 *ptep = data.pte; 377 if (level) 378 *level = data.level; 379 } 380 381 return ret; 382} 383 384struct hyp_map_data { 385 const u64 phys; 386 kvm_pte_t attr; 387}; 388 389static int hyp_set_prot_attr(enum kvm_pgtable_prot prot, kvm_pte_t *ptep) 390{ 391 bool device = prot & KVM_PGTABLE_PROT_DEVICE; 392 u32 mtype = device ? MT_DEVICE_nGnRE : MT_NORMAL; 393 kvm_pte_t attr = FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_ATTRIDX, mtype); 394 u32 sh = KVM_PTE_LEAF_ATTR_LO_S1_SH_IS; 395 u32 ap = (prot & KVM_PGTABLE_PROT_W) ? KVM_PTE_LEAF_ATTR_LO_S1_AP_RW : 396 KVM_PTE_LEAF_ATTR_LO_S1_AP_RO; 397 398 if (!(prot & KVM_PGTABLE_PROT_R)) 399 return -EINVAL; 400 401 if (prot & KVM_PGTABLE_PROT_X) { 402 if (prot & KVM_PGTABLE_PROT_W) 403 return -EINVAL; 404 405 if (device) 406 return -EINVAL; 407 408 if (system_supports_bti_kernel()) 409 attr |= KVM_PTE_LEAF_ATTR_HI_S1_GP; 410 } else { 411 attr |= KVM_PTE_LEAF_ATTR_HI_S1_XN; 412 } 413 414 attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_AP, ap); 415 if (!kvm_lpa2_is_enabled()) 416 attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_SH, sh); 417 attr |= KVM_PTE_LEAF_ATTR_LO_S1_AF; 418 attr |= prot & KVM_PTE_LEAF_ATTR_HI_SW; 419 *ptep = attr; 420 421 return 0; 422} 423 424enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte) 425{ 426 enum kvm_pgtable_prot prot = pte & KVM_PTE_LEAF_ATTR_HI_SW; 427 u32 ap; 428 429 if (!kvm_pte_valid(pte)) 430 return prot; 431 432 if (!(pte & KVM_PTE_LEAF_ATTR_HI_S1_XN)) 433 prot |= KVM_PGTABLE_PROT_X; 434 435 ap = FIELD_GET(KVM_PTE_LEAF_ATTR_LO_S1_AP, pte); 436 if (ap == KVM_PTE_LEAF_ATTR_LO_S1_AP_RO) 437 prot |= KVM_PGTABLE_PROT_R; 438 else if (ap == KVM_PTE_LEAF_ATTR_LO_S1_AP_RW) 439 prot |= KVM_PGTABLE_PROT_RW; 440 441 return prot; 442} 443 444static bool hyp_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx, 445 struct hyp_map_data *data) 446{ 447 u64 phys = data->phys + (ctx->addr - ctx->start); 448 kvm_pte_t new; 449 450 if (!kvm_block_mapping_supported(ctx, phys)) 451 return false; 452 453 new = kvm_init_valid_leaf_pte(phys, data->attr, ctx->level); 454 if (ctx->old == new) 455 return true; 456 if (!kvm_pte_valid(ctx->old)) 457 ctx->mm_ops->get_page(ctx->ptep); 458 else if (WARN_ON((ctx->old ^ new) & ~KVM_PTE_LEAF_ATTR_HI_SW)) 459 return false; 460 461 smp_store_release(ctx->ptep, new); 462 return true; 463} 464 465static int hyp_map_walker(const struct kvm_pgtable_visit_ctx *ctx, 466 enum kvm_pgtable_walk_flags visit) 467{ 468 kvm_pte_t *childp, new; 469 struct hyp_map_data *data = ctx->arg; 470 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops; 471 472 if (hyp_map_walker_try_leaf(ctx, data)) 473 return 0; 474 475 if (WARN_ON(ctx->level == KVM_PGTABLE_LAST_LEVEL)) 476 return -EINVAL; 477 478 childp = (kvm_pte_t *)mm_ops->zalloc_page(NULL); 479 if (!childp) 480 return -ENOMEM; 481 482 new = kvm_init_table_pte(childp, mm_ops); 483 mm_ops->get_page(ctx->ptep); 484 smp_store_release(ctx->ptep, new); 485 486 return 0; 487} 488 489int kvm_pgtable_hyp_map(struct kvm_pgtable *pgt, u64 addr, u64 size, u64 phys, 490 enum kvm_pgtable_prot prot) 491{ 492 int ret; 493 struct hyp_map_data map_data = { 494 .phys = ALIGN_DOWN(phys, PAGE_SIZE), 495 }; 496 struct kvm_pgtable_walker walker = { 497 .cb = hyp_map_walker, 498 .flags = KVM_PGTABLE_WALK_LEAF, 499 .arg = &map_data, 500 }; 501 502 ret = hyp_set_prot_attr(prot, &map_data.attr); 503 if (ret) 504 return ret; 505 506 ret = kvm_pgtable_walk(pgt, addr, size, &walker); 507 dsb(ishst); 508 isb(); 509 return ret; 510} 511 512static int hyp_unmap_walker(const struct kvm_pgtable_visit_ctx *ctx, 513 enum kvm_pgtable_walk_flags visit) 514{ 515 kvm_pte_t *childp = NULL; 516 u64 granule = kvm_granule_size(ctx->level); 517 u64 *unmapped = ctx->arg; 518 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops; 519 520 if (!kvm_pte_valid(ctx->old)) 521 return -EINVAL; 522 523 if (kvm_pte_table(ctx->old, ctx->level)) { 524 childp = kvm_pte_follow(ctx->old, mm_ops); 525 526 if (mm_ops->page_count(childp) != 1) 527 return 0; 528 529 kvm_clear_pte(ctx->ptep); 530 dsb(ishst); 531 __tlbi_level(vae2is, __TLBI_VADDR(ctx->addr, 0), TLBI_TTL_UNKNOWN); 532 } else { 533 if (ctx->end - ctx->addr < granule) 534 return -EINVAL; 535 536 kvm_clear_pte(ctx->ptep); 537 dsb(ishst); 538 __tlbi_level(vale2is, __TLBI_VADDR(ctx->addr, 0), ctx->level); 539 *unmapped += granule; 540 } 541 542 dsb(ish); 543 isb(); 544 mm_ops->put_page(ctx->ptep); 545 546 if (childp) 547 mm_ops->put_page(childp); 548 549 return 0; 550} 551 552u64 kvm_pgtable_hyp_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size) 553{ 554 u64 unmapped = 0; 555 struct kvm_pgtable_walker walker = { 556 .cb = hyp_unmap_walker, 557 .arg = &unmapped, 558 .flags = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST, 559 }; 560 561 if (!pgt->mm_ops->page_count) 562 return 0; 563 564 kvm_pgtable_walk(pgt, addr, size, &walker); 565 return unmapped; 566} 567 568int kvm_pgtable_hyp_init(struct kvm_pgtable *pgt, u32 va_bits, 569 struct kvm_pgtable_mm_ops *mm_ops) 570{ 571 s8 start_level = KVM_PGTABLE_LAST_LEVEL + 1 - 572 ARM64_HW_PGTABLE_LEVELS(va_bits); 573 574 if (start_level < KVM_PGTABLE_FIRST_LEVEL || 575 start_level > KVM_PGTABLE_LAST_LEVEL) 576 return -EINVAL; 577 578 pgt->pgd = (kvm_pteref_t)mm_ops->zalloc_page(NULL); 579 if (!pgt->pgd) 580 return -ENOMEM; 581 582 pgt->ia_bits = va_bits; 583 pgt->start_level = start_level; 584 pgt->mm_ops = mm_ops; 585 pgt->mmu = NULL; 586 pgt->force_pte_cb = NULL; 587 588 return 0; 589} 590 591static int hyp_free_walker(const struct kvm_pgtable_visit_ctx *ctx, 592 enum kvm_pgtable_walk_flags visit) 593{ 594 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops; 595 596 if (!kvm_pte_valid(ctx->old)) 597 return 0; 598 599 mm_ops->put_page(ctx->ptep); 600 601 if (kvm_pte_table(ctx->old, ctx->level)) 602 mm_ops->put_page(kvm_pte_follow(ctx->old, mm_ops)); 603 604 return 0; 605} 606 607void kvm_pgtable_hyp_destroy(struct kvm_pgtable *pgt) 608{ 609 struct kvm_pgtable_walker walker = { 610 .cb = hyp_free_walker, 611 .flags = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST, 612 }; 613 614 WARN_ON(kvm_pgtable_walk(pgt, 0, BIT(pgt->ia_bits), &walker)); 615 pgt->mm_ops->put_page(kvm_dereference_pteref(&walker, pgt->pgd)); 616 pgt->pgd = NULL; 617} 618 619struct stage2_map_data { 620 const u64 phys; 621 kvm_pte_t attr; 622 u8 owner_id; 623 624 kvm_pte_t *anchor; 625 kvm_pte_t *childp; 626 627 struct kvm_s2_mmu *mmu; 628 void *memcache; 629 630 /* Force mappings to page granularity */ 631 bool force_pte; 632}; 633 634u64 kvm_get_vtcr(u64 mmfr0, u64 mmfr1, u32 phys_shift) 635{ 636 u64 vtcr = VTCR_EL2_FLAGS; 637 s8 lvls; 638 639 vtcr |= kvm_get_parange(mmfr0) << VTCR_EL2_PS_SHIFT; 640 vtcr |= VTCR_EL2_T0SZ(phys_shift); 641 /* 642 * Use a minimum 2 level page table to prevent splitting 643 * host PMD huge pages at stage2. 644 */ 645 lvls = stage2_pgtable_levels(phys_shift); 646 if (lvls < 2) 647 lvls = 2; 648 649 /* 650 * When LPA2 is enabled, the HW supports an extra level of translation 651 * (for 5 in total) when using 4K pages. It also introduces VTCR_EL2.SL2 652 * to as an addition to SL0 to enable encoding this extra start level. 653 * However, since we always use concatenated pages for the first level 654 * lookup, we will never need this extra level and therefore do not need 655 * to touch SL2. 656 */ 657 vtcr |= VTCR_EL2_LVLS_TO_SL0(lvls); 658 659#ifdef CONFIG_ARM64_HW_AFDBM 660 /* 661 * Enable the Hardware Access Flag management, unconditionally 662 * on all CPUs. In systems that have asymmetric support for the feature 663 * this allows KVM to leverage hardware support on the subset of cores 664 * that implement the feature. 665 * 666 * The architecture requires VTCR_EL2.HA to be RES0 (thus ignored by 667 * hardware) on implementations that do not advertise support for the 668 * feature. As such, setting HA unconditionally is safe, unless you 669 * happen to be running on a design that has unadvertised support for 670 * HAFDBS. Here be dragons. 671 */ 672 if (!cpus_have_final_cap(ARM64_WORKAROUND_AMPERE_AC03_CPU_38)) 673 vtcr |= VTCR_EL2_HA; 674#endif /* CONFIG_ARM64_HW_AFDBM */ 675 676 if (kvm_lpa2_is_enabled()) 677 vtcr |= VTCR_EL2_DS; 678 679 /* Set the vmid bits */ 680 vtcr |= (get_vmid_bits(mmfr1) == 16) ? 681 VTCR_EL2_VS_16BIT : 682 VTCR_EL2_VS_8BIT; 683 684 return vtcr; 685} 686 687static bool stage2_has_fwb(struct kvm_pgtable *pgt) 688{ 689 if (!cpus_have_final_cap(ARM64_HAS_STAGE2_FWB)) 690 return false; 691 692 return !(pgt->flags & KVM_PGTABLE_S2_NOFWB); 693} 694 695void kvm_tlb_flush_vmid_range(struct kvm_s2_mmu *mmu, 696 phys_addr_t addr, size_t size) 697{ 698 unsigned long pages, inval_pages; 699 700 if (!system_supports_tlb_range()) { 701 kvm_call_hyp(__kvm_tlb_flush_vmid, mmu); 702 return; 703 } 704 705 pages = size >> PAGE_SHIFT; 706 while (pages > 0) { 707 inval_pages = min(pages, MAX_TLBI_RANGE_PAGES); 708 kvm_call_hyp(__kvm_tlb_flush_vmid_range, mmu, addr, inval_pages); 709 710 addr += inval_pages << PAGE_SHIFT; 711 pages -= inval_pages; 712 } 713} 714 715#define KVM_S2_MEMATTR(pgt, attr) PAGE_S2_MEMATTR(attr, stage2_has_fwb(pgt)) 716 717static int stage2_set_prot_attr(struct kvm_pgtable *pgt, enum kvm_pgtable_prot prot, 718 kvm_pte_t *ptep) 719{ 720 kvm_pte_t attr; 721 u32 sh = KVM_PTE_LEAF_ATTR_LO_S2_SH_IS; 722 723 switch (prot & (KVM_PGTABLE_PROT_DEVICE | 724 KVM_PGTABLE_PROT_NORMAL_NC)) { 725 case KVM_PGTABLE_PROT_DEVICE | KVM_PGTABLE_PROT_NORMAL_NC: 726 return -EINVAL; 727 case KVM_PGTABLE_PROT_DEVICE: 728 if (prot & KVM_PGTABLE_PROT_X) 729 return -EINVAL; 730 attr = KVM_S2_MEMATTR(pgt, DEVICE_nGnRE); 731 break; 732 case KVM_PGTABLE_PROT_NORMAL_NC: 733 if (prot & KVM_PGTABLE_PROT_X) 734 return -EINVAL; 735 attr = KVM_S2_MEMATTR(pgt, NORMAL_NC); 736 break; 737 default: 738 attr = KVM_S2_MEMATTR(pgt, NORMAL); 739 } 740 741 if (!(prot & KVM_PGTABLE_PROT_X)) 742 attr |= KVM_PTE_LEAF_ATTR_HI_S2_XN; 743 744 if (prot & KVM_PGTABLE_PROT_R) 745 attr |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R; 746 747 if (prot & KVM_PGTABLE_PROT_W) 748 attr |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W; 749 750 if (!kvm_lpa2_is_enabled()) 751 attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S2_SH, sh); 752 753 attr |= KVM_PTE_LEAF_ATTR_LO_S2_AF; 754 attr |= prot & KVM_PTE_LEAF_ATTR_HI_SW; 755 *ptep = attr; 756 757 return 0; 758} 759 760enum kvm_pgtable_prot kvm_pgtable_stage2_pte_prot(kvm_pte_t pte) 761{ 762 enum kvm_pgtable_prot prot = pte & KVM_PTE_LEAF_ATTR_HI_SW; 763 764 if (!kvm_pte_valid(pte)) 765 return prot; 766 767 if (pte & KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R) 768 prot |= KVM_PGTABLE_PROT_R; 769 if (pte & KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W) 770 prot |= KVM_PGTABLE_PROT_W; 771 if (!(pte & KVM_PTE_LEAF_ATTR_HI_S2_XN)) 772 prot |= KVM_PGTABLE_PROT_X; 773 774 return prot; 775} 776 777static bool stage2_pte_needs_update(kvm_pte_t old, kvm_pte_t new) 778{ 779 if (!kvm_pte_valid(old) || !kvm_pte_valid(new)) 780 return true; 781 782 return ((old ^ new) & (~KVM_PTE_LEAF_ATTR_S2_PERMS)); 783} 784 785static bool stage2_pte_is_counted(kvm_pte_t pte) 786{ 787 /* 788 * The refcount tracks valid entries as well as invalid entries if they 789 * encode ownership of a page to another entity than the page-table 790 * owner, whose id is 0. 791 */ 792 return !!pte; 793} 794 795static bool stage2_pte_is_locked(kvm_pte_t pte) 796{ 797 return !kvm_pte_valid(pte) && (pte & KVM_INVALID_PTE_LOCKED); 798} 799 800static bool stage2_try_set_pte(const struct kvm_pgtable_visit_ctx *ctx, kvm_pte_t new) 801{ 802 if (!kvm_pgtable_walk_shared(ctx)) { 803 WRITE_ONCE(*ctx->ptep, new); 804 return true; 805 } 806 807 return cmpxchg(ctx->ptep, ctx->old, new) == ctx->old; 808} 809 810/** 811 * stage2_try_break_pte() - Invalidates a pte according to the 812 * 'break-before-make' requirements of the 813 * architecture. 814 * 815 * @ctx: context of the visited pte. 816 * @mmu: stage-2 mmu 817 * 818 * Returns: true if the pte was successfully broken. 819 * 820 * If the removed pte was valid, performs the necessary serialization and TLB 821 * invalidation for the old value. For counted ptes, drops the reference count 822 * on the containing table page. 823 */ 824static bool stage2_try_break_pte(const struct kvm_pgtable_visit_ctx *ctx, 825 struct kvm_s2_mmu *mmu) 826{ 827 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops; 828 829 if (stage2_pte_is_locked(ctx->old)) { 830 /* 831 * Should never occur if this walker has exclusive access to the 832 * page tables. 833 */ 834 WARN_ON(!kvm_pgtable_walk_shared(ctx)); 835 return false; 836 } 837 838 if (!stage2_try_set_pte(ctx, KVM_INVALID_PTE_LOCKED)) 839 return false; 840 841 if (!kvm_pgtable_walk_skip_bbm_tlbi(ctx)) { 842 /* 843 * Perform the appropriate TLB invalidation based on the 844 * evicted pte value (if any). 845 */ 846 if (kvm_pte_table(ctx->old, ctx->level)) { 847 u64 size = kvm_granule_size(ctx->level); 848 u64 addr = ALIGN_DOWN(ctx->addr, size); 849 850 kvm_tlb_flush_vmid_range(mmu, addr, size); 851 } else if (kvm_pte_valid(ctx->old)) { 852 kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu, 853 ctx->addr, ctx->level); 854 } 855 } 856 857 if (stage2_pte_is_counted(ctx->old)) 858 mm_ops->put_page(ctx->ptep); 859 860 return true; 861} 862 863static void stage2_make_pte(const struct kvm_pgtable_visit_ctx *ctx, kvm_pte_t new) 864{ 865 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops; 866 867 WARN_ON(!stage2_pte_is_locked(*ctx->ptep)); 868 869 if (stage2_pte_is_counted(new)) 870 mm_ops->get_page(ctx->ptep); 871 872 smp_store_release(ctx->ptep, new); 873} 874 875static bool stage2_unmap_defer_tlb_flush(struct kvm_pgtable *pgt) 876{ 877 /* 878 * If FEAT_TLBIRANGE is implemented, defer the individual 879 * TLB invalidations until the entire walk is finished, and 880 * then use the range-based TLBI instructions to do the 881 * invalidations. Condition deferred TLB invalidation on the 882 * system supporting FWB as the optimization is entirely 883 * pointless when the unmap walker needs to perform CMOs. 884 */ 885 return system_supports_tlb_range() && stage2_has_fwb(pgt); 886} 887 888static void stage2_unmap_put_pte(const struct kvm_pgtable_visit_ctx *ctx, 889 struct kvm_s2_mmu *mmu, 890 struct kvm_pgtable_mm_ops *mm_ops) 891{ 892 struct kvm_pgtable *pgt = ctx->arg; 893 894 /* 895 * Clear the existing PTE, and perform break-before-make if it was 896 * valid. Depending on the system support, defer the TLB maintenance 897 * for the same until the entire unmap walk is completed. 898 */ 899 if (kvm_pte_valid(ctx->old)) { 900 kvm_clear_pte(ctx->ptep); 901 902 if (kvm_pte_table(ctx->old, ctx->level)) { 903 kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu, ctx->addr, 904 TLBI_TTL_UNKNOWN); 905 } else if (!stage2_unmap_defer_tlb_flush(pgt)) { 906 kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu, ctx->addr, 907 ctx->level); 908 } 909 } 910 911 mm_ops->put_page(ctx->ptep); 912} 913 914static bool stage2_pte_cacheable(struct kvm_pgtable *pgt, kvm_pte_t pte) 915{ 916 u64 memattr = pte & KVM_PTE_LEAF_ATTR_LO_S2_MEMATTR; 917 return memattr == KVM_S2_MEMATTR(pgt, NORMAL); 918} 919 920static bool stage2_pte_executable(kvm_pte_t pte) 921{ 922 return !(pte & KVM_PTE_LEAF_ATTR_HI_S2_XN); 923} 924 925static u64 stage2_map_walker_phys_addr(const struct kvm_pgtable_visit_ctx *ctx, 926 const struct stage2_map_data *data) 927{ 928 u64 phys = data->phys; 929 930 /* 931 * Stage-2 walks to update ownership data are communicated to the map 932 * walker using an invalid PA. Avoid offsetting an already invalid PA, 933 * which could overflow and make the address valid again. 934 */ 935 if (!kvm_phys_is_valid(phys)) 936 return phys; 937 938 /* 939 * Otherwise, work out the correct PA based on how far the walk has 940 * gotten. 941 */ 942 return phys + (ctx->addr - ctx->start); 943} 944 945static bool stage2_leaf_mapping_allowed(const struct kvm_pgtable_visit_ctx *ctx, 946 struct stage2_map_data *data) 947{ 948 u64 phys = stage2_map_walker_phys_addr(ctx, data); 949 950 if (data->force_pte && ctx->level < KVM_PGTABLE_LAST_LEVEL) 951 return false; 952 953 return kvm_block_mapping_supported(ctx, phys); 954} 955 956static int stage2_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx, 957 struct stage2_map_data *data) 958{ 959 kvm_pte_t new; 960 u64 phys = stage2_map_walker_phys_addr(ctx, data); 961 u64 granule = kvm_granule_size(ctx->level); 962 struct kvm_pgtable *pgt = data->mmu->pgt; 963 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops; 964 965 if (!stage2_leaf_mapping_allowed(ctx, data)) 966 return -E2BIG; 967 968 if (kvm_phys_is_valid(phys)) 969 new = kvm_init_valid_leaf_pte(phys, data->attr, ctx->level); 970 else 971 new = kvm_init_invalid_leaf_owner(data->owner_id); 972 973 /* 974 * Skip updating the PTE if we are trying to recreate the exact 975 * same mapping or only change the access permissions. Instead, 976 * the vCPU will exit one more time from guest if still needed 977 * and then go through the path of relaxing permissions. 978 */ 979 if (!stage2_pte_needs_update(ctx->old, new)) 980 return -EAGAIN; 981 982 if (!stage2_try_break_pte(ctx, data->mmu)) 983 return -EAGAIN; 984 985 /* Perform CMOs before installation of the guest stage-2 PTE */ 986 if (!kvm_pgtable_walk_skip_cmo(ctx) && mm_ops->dcache_clean_inval_poc && 987 stage2_pte_cacheable(pgt, new)) 988 mm_ops->dcache_clean_inval_poc(kvm_pte_follow(new, mm_ops), 989 granule); 990 991 if (!kvm_pgtable_walk_skip_cmo(ctx) && mm_ops->icache_inval_pou && 992 stage2_pte_executable(new)) 993 mm_ops->icache_inval_pou(kvm_pte_follow(new, mm_ops), granule); 994 995 stage2_make_pte(ctx, new); 996 997 return 0; 998} 999 1000static int stage2_map_walk_table_pre(const struct kvm_pgtable_visit_ctx *ctx, 1001 struct stage2_map_data *data) 1002{ 1003 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops; 1004 kvm_pte_t *childp = kvm_pte_follow(ctx->old, mm_ops); 1005 int ret; 1006 1007 if (!stage2_leaf_mapping_allowed(ctx, data)) 1008 return 0; 1009 1010 ret = stage2_map_walker_try_leaf(ctx, data); 1011 if (ret) 1012 return ret; 1013 1014 mm_ops->free_unlinked_table(childp, ctx->level); 1015 return 0; 1016} 1017 1018static int stage2_map_walk_leaf(const struct kvm_pgtable_visit_ctx *ctx, 1019 struct stage2_map_data *data) 1020{ 1021 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops; 1022 kvm_pte_t *childp, new; 1023 int ret; 1024 1025 ret = stage2_map_walker_try_leaf(ctx, data); 1026 if (ret != -E2BIG) 1027 return ret; 1028 1029 if (WARN_ON(ctx->level == KVM_PGTABLE_LAST_LEVEL)) 1030 return -EINVAL; 1031 1032 if (!data->memcache) 1033 return -ENOMEM; 1034 1035 childp = mm_ops->zalloc_page(data->memcache); 1036 if (!childp) 1037 return -ENOMEM; 1038 1039 if (!stage2_try_break_pte(ctx, data->mmu)) { 1040 mm_ops->put_page(childp); 1041 return -EAGAIN; 1042 } 1043 1044 /* 1045 * If we've run into an existing block mapping then replace it with 1046 * a table. Accesses beyond 'end' that fall within the new table 1047 * will be mapped lazily. 1048 */ 1049 new = kvm_init_table_pte(childp, mm_ops); 1050 stage2_make_pte(ctx, new); 1051 1052 return 0; 1053} 1054 1055/* 1056 * The TABLE_PRE callback runs for table entries on the way down, looking 1057 * for table entries which we could conceivably replace with a block entry 1058 * for this mapping. If it finds one it replaces the entry and calls 1059 * kvm_pgtable_mm_ops::free_unlinked_table() to tear down the detached table. 1060 * 1061 * Otherwise, the LEAF callback performs the mapping at the existing leaves 1062 * instead. 1063 */ 1064static int stage2_map_walker(const struct kvm_pgtable_visit_ctx *ctx, 1065 enum kvm_pgtable_walk_flags visit) 1066{ 1067 struct stage2_map_data *data = ctx->arg; 1068 1069 switch (visit) { 1070 case KVM_PGTABLE_WALK_TABLE_PRE: 1071 return stage2_map_walk_table_pre(ctx, data); 1072 case KVM_PGTABLE_WALK_LEAF: 1073 return stage2_map_walk_leaf(ctx, data); 1074 default: 1075 return -EINVAL; 1076 } 1077} 1078 1079int kvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size, 1080 u64 phys, enum kvm_pgtable_prot prot, 1081 void *mc, enum kvm_pgtable_walk_flags flags) 1082{ 1083 int ret; 1084 struct stage2_map_data map_data = { 1085 .phys = ALIGN_DOWN(phys, PAGE_SIZE), 1086 .mmu = pgt->mmu, 1087 .memcache = mc, 1088 .force_pte = pgt->force_pte_cb && pgt->force_pte_cb(addr, addr + size, prot), 1089 }; 1090 struct kvm_pgtable_walker walker = { 1091 .cb = stage2_map_walker, 1092 .flags = flags | 1093 KVM_PGTABLE_WALK_TABLE_PRE | 1094 KVM_PGTABLE_WALK_LEAF, 1095 .arg = &map_data, 1096 }; 1097 1098 if (WARN_ON((pgt->flags & KVM_PGTABLE_S2_IDMAP) && (addr != phys))) 1099 return -EINVAL; 1100 1101 ret = stage2_set_prot_attr(pgt, prot, &map_data.attr); 1102 if (ret) 1103 return ret; 1104 1105 ret = kvm_pgtable_walk(pgt, addr, size, &walker); 1106 dsb(ishst); 1107 return ret; 1108} 1109 1110int kvm_pgtable_stage2_set_owner(struct kvm_pgtable *pgt, u64 addr, u64 size, 1111 void *mc, u8 owner_id) 1112{ 1113 int ret; 1114 struct stage2_map_data map_data = { 1115 .phys = KVM_PHYS_INVALID, 1116 .mmu = pgt->mmu, 1117 .memcache = mc, 1118 .owner_id = owner_id, 1119 .force_pte = true, 1120 }; 1121 struct kvm_pgtable_walker walker = { 1122 .cb = stage2_map_walker, 1123 .flags = KVM_PGTABLE_WALK_TABLE_PRE | 1124 KVM_PGTABLE_WALK_LEAF, 1125 .arg = &map_data, 1126 }; 1127 1128 if (owner_id > KVM_MAX_OWNER_ID) 1129 return -EINVAL; 1130 1131 ret = kvm_pgtable_walk(pgt, addr, size, &walker); 1132 return ret; 1133} 1134 1135static int stage2_unmap_walker(const struct kvm_pgtable_visit_ctx *ctx, 1136 enum kvm_pgtable_walk_flags visit) 1137{ 1138 struct kvm_pgtable *pgt = ctx->arg; 1139 struct kvm_s2_mmu *mmu = pgt->mmu; 1140 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops; 1141 kvm_pte_t *childp = NULL; 1142 bool need_flush = false; 1143 1144 if (!kvm_pte_valid(ctx->old)) { 1145 if (stage2_pte_is_counted(ctx->old)) { 1146 kvm_clear_pte(ctx->ptep); 1147 mm_ops->put_page(ctx->ptep); 1148 } 1149 return 0; 1150 } 1151 1152 if (kvm_pte_table(ctx->old, ctx->level)) { 1153 childp = kvm_pte_follow(ctx->old, mm_ops); 1154 1155 if (mm_ops->page_count(childp) != 1) 1156 return 0; 1157 } else if (stage2_pte_cacheable(pgt, ctx->old)) { 1158 need_flush = !stage2_has_fwb(pgt); 1159 } 1160 1161 /* 1162 * This is similar to the map() path in that we unmap the entire 1163 * block entry and rely on the remaining portions being faulted 1164 * back lazily. 1165 */ 1166 stage2_unmap_put_pte(ctx, mmu, mm_ops); 1167 1168 if (need_flush && mm_ops->dcache_clean_inval_poc) 1169 mm_ops->dcache_clean_inval_poc(kvm_pte_follow(ctx->old, mm_ops), 1170 kvm_granule_size(ctx->level)); 1171 1172 if (childp) 1173 mm_ops->put_page(childp); 1174 1175 return 0; 1176} 1177 1178int kvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size) 1179{ 1180 int ret; 1181 struct kvm_pgtable_walker walker = { 1182 .cb = stage2_unmap_walker, 1183 .arg = pgt, 1184 .flags = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST, 1185 }; 1186 1187 ret = kvm_pgtable_walk(pgt, addr, size, &walker); 1188 if (stage2_unmap_defer_tlb_flush(pgt)) 1189 /* Perform the deferred TLB invalidations */ 1190 kvm_tlb_flush_vmid_range(pgt->mmu, addr, size); 1191 1192 return ret; 1193} 1194 1195struct stage2_attr_data { 1196 kvm_pte_t attr_set; 1197 kvm_pte_t attr_clr; 1198 kvm_pte_t pte; 1199 s8 level; 1200}; 1201 1202static int stage2_attr_walker(const struct kvm_pgtable_visit_ctx *ctx, 1203 enum kvm_pgtable_walk_flags visit) 1204{ 1205 kvm_pte_t pte = ctx->old; 1206 struct stage2_attr_data *data = ctx->arg; 1207 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops; 1208 1209 if (!kvm_pte_valid(ctx->old)) 1210 return -EAGAIN; 1211 1212 data->level = ctx->level; 1213 data->pte = pte; 1214 pte &= ~data->attr_clr; 1215 pte |= data->attr_set; 1216 1217 /* 1218 * We may race with the CPU trying to set the access flag here, 1219 * but worst-case the access flag update gets lost and will be 1220 * set on the next access instead. 1221 */ 1222 if (data->pte != pte) { 1223 /* 1224 * Invalidate instruction cache before updating the guest 1225 * stage-2 PTE if we are going to add executable permission. 1226 */ 1227 if (mm_ops->icache_inval_pou && 1228 stage2_pte_executable(pte) && !stage2_pte_executable(ctx->old)) 1229 mm_ops->icache_inval_pou(kvm_pte_follow(pte, mm_ops), 1230 kvm_granule_size(ctx->level)); 1231 1232 if (!stage2_try_set_pte(ctx, pte)) 1233 return -EAGAIN; 1234 } 1235 1236 return 0; 1237} 1238 1239static int stage2_update_leaf_attrs(struct kvm_pgtable *pgt, u64 addr, 1240 u64 size, kvm_pte_t attr_set, 1241 kvm_pte_t attr_clr, kvm_pte_t *orig_pte, 1242 s8 *level, enum kvm_pgtable_walk_flags flags) 1243{ 1244 int ret; 1245 kvm_pte_t attr_mask = KVM_PTE_LEAF_ATTR_LO | KVM_PTE_LEAF_ATTR_HI; 1246 struct stage2_attr_data data = { 1247 .attr_set = attr_set & attr_mask, 1248 .attr_clr = attr_clr & attr_mask, 1249 }; 1250 struct kvm_pgtable_walker walker = { 1251 .cb = stage2_attr_walker, 1252 .arg = &data, 1253 .flags = flags | KVM_PGTABLE_WALK_LEAF, 1254 }; 1255 1256 ret = kvm_pgtable_walk(pgt, addr, size, &walker); 1257 if (ret) 1258 return ret; 1259 1260 if (orig_pte) 1261 *orig_pte = data.pte; 1262 1263 if (level) 1264 *level = data.level; 1265 return 0; 1266} 1267 1268int kvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size) 1269{ 1270 return stage2_update_leaf_attrs(pgt, addr, size, 0, 1271 KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W, 1272 NULL, NULL, 0); 1273} 1274 1275kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr) 1276{ 1277 kvm_pte_t pte = 0; 1278 int ret; 1279 1280 ret = stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0, 1281 &pte, NULL, 1282 KVM_PGTABLE_WALK_HANDLE_FAULT | 1283 KVM_PGTABLE_WALK_SHARED); 1284 if (!ret) 1285 dsb(ishst); 1286 1287 return pte; 1288} 1289 1290struct stage2_age_data { 1291 bool mkold; 1292 bool young; 1293}; 1294 1295static int stage2_age_walker(const struct kvm_pgtable_visit_ctx *ctx, 1296 enum kvm_pgtable_walk_flags visit) 1297{ 1298 kvm_pte_t new = ctx->old & ~KVM_PTE_LEAF_ATTR_LO_S2_AF; 1299 struct stage2_age_data *data = ctx->arg; 1300 1301 if (!kvm_pte_valid(ctx->old) || new == ctx->old) 1302 return 0; 1303 1304 data->young = true; 1305 1306 /* 1307 * stage2_age_walker() is always called while holding the MMU lock for 1308 * write, so this will always succeed. Nonetheless, this deliberately 1309 * follows the race detection pattern of the other stage-2 walkers in 1310 * case the locking mechanics of the MMU notifiers is ever changed. 1311 */ 1312 if (data->mkold && !stage2_try_set_pte(ctx, new)) 1313 return -EAGAIN; 1314 1315 /* 1316 * "But where's the TLBI?!", you scream. 1317 * "Over in the core code", I sigh. 1318 * 1319 * See the '->clear_flush_young()' callback on the KVM mmu notifier. 1320 */ 1321 return 0; 1322} 1323 1324bool kvm_pgtable_stage2_test_clear_young(struct kvm_pgtable *pgt, u64 addr, 1325 u64 size, bool mkold) 1326{ 1327 struct stage2_age_data data = { 1328 .mkold = mkold, 1329 }; 1330 struct kvm_pgtable_walker walker = { 1331 .cb = stage2_age_walker, 1332 .arg = &data, 1333 .flags = KVM_PGTABLE_WALK_LEAF, 1334 }; 1335 1336 WARN_ON(kvm_pgtable_walk(pgt, addr, size, &walker)); 1337 return data.young; 1338} 1339 1340int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr, 1341 enum kvm_pgtable_prot prot) 1342{ 1343 int ret; 1344 s8 level; 1345 kvm_pte_t set = 0, clr = 0; 1346 1347 if (prot & KVM_PTE_LEAF_ATTR_HI_SW) 1348 return -EINVAL; 1349 1350 if (prot & KVM_PGTABLE_PROT_R) 1351 set |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_R; 1352 1353 if (prot & KVM_PGTABLE_PROT_W) 1354 set |= KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W; 1355 1356 if (prot & KVM_PGTABLE_PROT_X) 1357 clr |= KVM_PTE_LEAF_ATTR_HI_S2_XN; 1358 1359 ret = stage2_update_leaf_attrs(pgt, addr, 1, set, clr, NULL, &level, 1360 KVM_PGTABLE_WALK_HANDLE_FAULT | 1361 KVM_PGTABLE_WALK_SHARED); 1362 if (!ret || ret == -EAGAIN) 1363 kvm_call_hyp(__kvm_tlb_flush_vmid_ipa_nsh, pgt->mmu, addr, level); 1364 return ret; 1365} 1366 1367static int stage2_flush_walker(const struct kvm_pgtable_visit_ctx *ctx, 1368 enum kvm_pgtable_walk_flags visit) 1369{ 1370 struct kvm_pgtable *pgt = ctx->arg; 1371 struct kvm_pgtable_mm_ops *mm_ops = pgt->mm_ops; 1372 1373 if (!kvm_pte_valid(ctx->old) || !stage2_pte_cacheable(pgt, ctx->old)) 1374 return 0; 1375 1376 if (mm_ops->dcache_clean_inval_poc) 1377 mm_ops->dcache_clean_inval_poc(kvm_pte_follow(ctx->old, mm_ops), 1378 kvm_granule_size(ctx->level)); 1379 return 0; 1380} 1381 1382int kvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size) 1383{ 1384 struct kvm_pgtable_walker walker = { 1385 .cb = stage2_flush_walker, 1386 .flags = KVM_PGTABLE_WALK_LEAF, 1387 .arg = pgt, 1388 }; 1389 1390 if (stage2_has_fwb(pgt)) 1391 return 0; 1392 1393 return kvm_pgtable_walk(pgt, addr, size, &walker); 1394} 1395 1396kvm_pte_t *kvm_pgtable_stage2_create_unlinked(struct kvm_pgtable *pgt, 1397 u64 phys, s8 level, 1398 enum kvm_pgtable_prot prot, 1399 void *mc, bool force_pte) 1400{ 1401 struct stage2_map_data map_data = { 1402 .phys = phys, 1403 .mmu = pgt->mmu, 1404 .memcache = mc, 1405 .force_pte = force_pte, 1406 }; 1407 struct kvm_pgtable_walker walker = { 1408 .cb = stage2_map_walker, 1409 .flags = KVM_PGTABLE_WALK_LEAF | 1410 KVM_PGTABLE_WALK_SKIP_BBM_TLBI | 1411 KVM_PGTABLE_WALK_SKIP_CMO, 1412 .arg = &map_data, 1413 }; 1414 /* 1415 * The input address (.addr) is irrelevant for walking an 1416 * unlinked table. Construct an ambiguous IA range to map 1417 * kvm_granule_size(level) worth of memory. 1418 */ 1419 struct kvm_pgtable_walk_data data = { 1420 .walker = &walker, 1421 .addr = 0, 1422 .end = kvm_granule_size(level), 1423 }; 1424 struct kvm_pgtable_mm_ops *mm_ops = pgt->mm_ops; 1425 kvm_pte_t *pgtable; 1426 int ret; 1427 1428 if (!IS_ALIGNED(phys, kvm_granule_size(level))) 1429 return ERR_PTR(-EINVAL); 1430 1431 ret = stage2_set_prot_attr(pgt, prot, &map_data.attr); 1432 if (ret) 1433 return ERR_PTR(ret); 1434 1435 pgtable = mm_ops->zalloc_page(mc); 1436 if (!pgtable) 1437 return ERR_PTR(-ENOMEM); 1438 1439 ret = __kvm_pgtable_walk(&data, mm_ops, (kvm_pteref_t)pgtable, 1440 level + 1); 1441 if (ret) { 1442 kvm_pgtable_stage2_free_unlinked(mm_ops, pgtable, level); 1443 return ERR_PTR(ret); 1444 } 1445 1446 return pgtable; 1447} 1448 1449/* 1450 * Get the number of page-tables needed to replace a block with a 1451 * fully populated tree up to the PTE entries. Note that @level is 1452 * interpreted as in "level @level entry". 1453 */ 1454static int stage2_block_get_nr_page_tables(s8 level) 1455{ 1456 switch (level) { 1457 case 1: 1458 return PTRS_PER_PTE + 1; 1459 case 2: 1460 return 1; 1461 case 3: 1462 return 0; 1463 default: 1464 WARN_ON_ONCE(level < KVM_PGTABLE_MIN_BLOCK_LEVEL || 1465 level > KVM_PGTABLE_LAST_LEVEL); 1466 return -EINVAL; 1467 }; 1468} 1469 1470static int stage2_split_walker(const struct kvm_pgtable_visit_ctx *ctx, 1471 enum kvm_pgtable_walk_flags visit) 1472{ 1473 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops; 1474 struct kvm_mmu_memory_cache *mc = ctx->arg; 1475 struct kvm_s2_mmu *mmu; 1476 kvm_pte_t pte = ctx->old, new, *childp; 1477 enum kvm_pgtable_prot prot; 1478 s8 level = ctx->level; 1479 bool force_pte; 1480 int nr_pages; 1481 u64 phys; 1482 1483 /* No huge-pages exist at the last level */ 1484 if (level == KVM_PGTABLE_LAST_LEVEL) 1485 return 0; 1486 1487 /* We only split valid block mappings */ 1488 if (!kvm_pte_valid(pte)) 1489 return 0; 1490 1491 nr_pages = stage2_block_get_nr_page_tables(level); 1492 if (nr_pages < 0) 1493 return nr_pages; 1494 1495 if (mc->nobjs >= nr_pages) { 1496 /* Build a tree mapped down to the PTE granularity. */ 1497 force_pte = true; 1498 } else { 1499 /* 1500 * Don't force PTEs, so create_unlinked() below does 1501 * not populate the tree up to the PTE level. The 1502 * consequence is that the call will require a single 1503 * page of level 2 entries at level 1, or a single 1504 * page of PTEs at level 2. If we are at level 1, the 1505 * PTEs will be created recursively. 1506 */ 1507 force_pte = false; 1508 nr_pages = 1; 1509 } 1510 1511 if (mc->nobjs < nr_pages) 1512 return -ENOMEM; 1513 1514 mmu = container_of(mc, struct kvm_s2_mmu, split_page_cache); 1515 phys = kvm_pte_to_phys(pte); 1516 prot = kvm_pgtable_stage2_pte_prot(pte); 1517 1518 childp = kvm_pgtable_stage2_create_unlinked(mmu->pgt, phys, 1519 level, prot, mc, force_pte); 1520 if (IS_ERR(childp)) 1521 return PTR_ERR(childp); 1522 1523 if (!stage2_try_break_pte(ctx, mmu)) { 1524 kvm_pgtable_stage2_free_unlinked(mm_ops, childp, level); 1525 return -EAGAIN; 1526 } 1527 1528 /* 1529 * Note, the contents of the page table are guaranteed to be made 1530 * visible before the new PTE is assigned because stage2_make_pte() 1531 * writes the PTE using smp_store_release(). 1532 */ 1533 new = kvm_init_table_pte(childp, mm_ops); 1534 stage2_make_pte(ctx, new); 1535 dsb(ishst); 1536 return 0; 1537} 1538 1539int kvm_pgtable_stage2_split(struct kvm_pgtable *pgt, u64 addr, u64 size, 1540 struct kvm_mmu_memory_cache *mc) 1541{ 1542 struct kvm_pgtable_walker walker = { 1543 .cb = stage2_split_walker, 1544 .flags = KVM_PGTABLE_WALK_LEAF, 1545 .arg = mc, 1546 }; 1547 1548 return kvm_pgtable_walk(pgt, addr, size, &walker); 1549} 1550 1551int __kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu, 1552 struct kvm_pgtable_mm_ops *mm_ops, 1553 enum kvm_pgtable_stage2_flags flags, 1554 kvm_pgtable_force_pte_cb_t force_pte_cb) 1555{ 1556 size_t pgd_sz; 1557 u64 vtcr = mmu->vtcr; 1558 u32 ia_bits = VTCR_EL2_IPA(vtcr); 1559 u32 sl0 = FIELD_GET(VTCR_EL2_SL0_MASK, vtcr); 1560 s8 start_level = VTCR_EL2_TGRAN_SL0_BASE - sl0; 1561 1562 pgd_sz = kvm_pgd_pages(ia_bits, start_level) * PAGE_SIZE; 1563 pgt->pgd = (kvm_pteref_t)mm_ops->zalloc_pages_exact(pgd_sz); 1564 if (!pgt->pgd) 1565 return -ENOMEM; 1566 1567 pgt->ia_bits = ia_bits; 1568 pgt->start_level = start_level; 1569 pgt->mm_ops = mm_ops; 1570 pgt->mmu = mmu; 1571 pgt->flags = flags; 1572 pgt->force_pte_cb = force_pte_cb; 1573 1574 /* Ensure zeroed PGD pages are visible to the hardware walker */ 1575 dsb(ishst); 1576 return 0; 1577} 1578 1579size_t kvm_pgtable_stage2_pgd_size(u64 vtcr) 1580{ 1581 u32 ia_bits = VTCR_EL2_IPA(vtcr); 1582 u32 sl0 = FIELD_GET(VTCR_EL2_SL0_MASK, vtcr); 1583 s8 start_level = VTCR_EL2_TGRAN_SL0_BASE - sl0; 1584 1585 return kvm_pgd_pages(ia_bits, start_level) * PAGE_SIZE; 1586} 1587 1588static int stage2_free_walker(const struct kvm_pgtable_visit_ctx *ctx, 1589 enum kvm_pgtable_walk_flags visit) 1590{ 1591 struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops; 1592 1593 if (!stage2_pte_is_counted(ctx->old)) 1594 return 0; 1595 1596 mm_ops->put_page(ctx->ptep); 1597 1598 if (kvm_pte_table(ctx->old, ctx->level)) 1599 mm_ops->put_page(kvm_pte_follow(ctx->old, mm_ops)); 1600 1601 return 0; 1602} 1603 1604void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt) 1605{ 1606 size_t pgd_sz; 1607 struct kvm_pgtable_walker walker = { 1608 .cb = stage2_free_walker, 1609 .flags = KVM_PGTABLE_WALK_LEAF | 1610 KVM_PGTABLE_WALK_TABLE_POST, 1611 }; 1612 1613 WARN_ON(kvm_pgtable_walk(pgt, 0, BIT(pgt->ia_bits), &walker)); 1614 pgd_sz = kvm_pgd_pages(pgt->ia_bits, pgt->start_level) * PAGE_SIZE; 1615 pgt->mm_ops->free_pages_exact(kvm_dereference_pteref(&walker, pgt->pgd), pgd_sz); 1616 pgt->pgd = NULL; 1617} 1618 1619void kvm_pgtable_stage2_free_unlinked(struct kvm_pgtable_mm_ops *mm_ops, void *pgtable, s8 level) 1620{ 1621 kvm_pteref_t ptep = (kvm_pteref_t)pgtable; 1622 struct kvm_pgtable_walker walker = { 1623 .cb = stage2_free_walker, 1624 .flags = KVM_PGTABLE_WALK_LEAF | 1625 KVM_PGTABLE_WALK_TABLE_POST, 1626 }; 1627 struct kvm_pgtable_walk_data data = { 1628 .walker = &walker, 1629 1630 /* 1631 * At this point the IPA really doesn't matter, as the page 1632 * table being traversed has already been removed from the stage 1633 * 2. Set an appropriate range to cover the entire page table. 1634 */ 1635 .addr = 0, 1636 .end = kvm_granule_size(level), 1637 }; 1638 1639 WARN_ON(__kvm_pgtable_walk(&data, mm_ops, ptep, level + 1)); 1640 1641 WARN_ON(mm_ops->page_count(pgtable) != 1); 1642 mm_ops->put_page(pgtable); 1643} 1644