drivers/iommu/amd/io_pgtable.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * CPU-agnostic AMD IO page table allocator.
   4  *
   5  * Copyright (C) 2020 Advanced Micro Devices, Inc.
   6  * Author: Suravee Suthikulpanit <[email protected]>
   7  */
   8
   9 #define pr_fmt(fmt)     "AMD-Vi: " fmt
  10 #define dev_fmt(fmt)    pr_fmt(fmt)
  11
  12 #include <linux/atomic.h>
  13 #include <linux/bitops.h>
  14 #include <linux/io-pgtable.h>
  15 #include <linux/kernel.h>
  16 #include <linux/sizes.h>
  17 #include <linux/slab.h>
  18 #include <linux/types.h>
  19 #include <linux/dma-mapping.h>
  20
  21 #include <asm/barrier.h>
  22
  23 #include "amd_iommu_types.h"
  24 #include "amd_iommu.h"
  25 #include "../iommu-pages.h"
  26
  27 /*
  28  * Helper function to get the first pte of a large mapping
  29  */
  30 static u64 *first_pte_l7(u64 *pte, unsigned long *page_size,
  31                          unsigned long *count)
  32 {
  33         unsigned long pte_mask, pg_size, cnt;
  34         u64 *fpte;
  35
  36         pg_size  = PTE_PAGE_SIZE(*pte);
  37         cnt      = PAGE_SIZE_PTE_COUNT(pg_size);
  38         pte_mask = ~((cnt << 3) - 1);
  39         fpte     = (u64 *)(((unsigned long)pte) & pte_mask);
  40
  41         if (page_size)
  42                 *page_size = pg_size;
  43
  44         if (count)
  45                 *count = cnt;
  46
  47         return fpte;
  48 }
  49
  50 /****************************************************************************
  51  *
  52  * The functions below are used the create the page table mappings for
  53  * unity mapped regions.
  54  *
  55  ****************************************************************************/
  56
  57 static void free_pt_page(u64 *pt, struct list_head *freelist)
  58 {
  59         struct page *p = virt_to_page(pt);
  60
  61         list_add_tail(&p->lru, freelist);
  62 }
  63
  64 static void free_pt_lvl(u64 *pt, struct list_head *freelist, int lvl)
  65 {
  66         u64 *p;
  67         int i;
  68
  69         for (i = 0; i < 512; ++i) {
  70                 /* PTE present? */
  71                 if (!IOMMU_PTE_PRESENT(pt[i]))
  72                         continue;
  73
  74                 /* Large PTE? */
  75                 if (PM_PTE_LEVEL(pt[i]) == 0 ||
  76                     PM_PTE_LEVEL(pt[i]) == 7)
  77                         continue;
  78
  79                 /*
  80                  * Free the next level. No need to look at l1 tables here since
  81                  * they can only contain leaf PTEs; just free them directly.
  82                  */
  83                 p = IOMMU_PTE_PAGE(pt[i]);
  84                 if (lvl > 2)
  85                         free_pt_lvl(p, freelist, lvl - 1);
  86                 else
  87                         free_pt_page(p, freelist);
  88         }
  89
  90         free_pt_page(pt, freelist);
  91 }
  92
  93 static void free_sub_pt(u64 *root, int mode, struct list_head *freelist)
  94 {
  95         switch (mode) {
  96         case PAGE_MODE_NONE:
  97         case PAGE_MODE_7_LEVEL:
  98                 break;
  99         case PAGE_MODE_1_LEVEL:
 100                 free_pt_page(root, freelist);
 101                 break;
 102         case PAGE_MODE_2_LEVEL:
 103         case PAGE_MODE_3_LEVEL:
 104         case PAGE_MODE_4_LEVEL:
 105         case PAGE_MODE_5_LEVEL:
 106         case PAGE_MODE_6_LEVEL:
 107                 free_pt_lvl(root, freelist, mode);
 108                 break;
 109         default:
 110                 BUG();
 111         }
 112 }
 113
 114 /*
 115  * This function is used to add another level to an IO page table. Adding
 116  * another level increases the size of the address space by 9 bits to a size up
 117  * to 64 bits.
 118  */
 119 static bool increase_address_space(struct amd_io_pgtable *pgtable,
 120                                    unsigned long address,
 121                                    unsigned int page_size_level,
 122                                    gfp_t gfp)
 123 {
 124         struct io_pgtable_cfg *cfg = &pgtable->pgtbl.cfg;
 125         struct protection_domain *domain =
 126                 container_of(pgtable, struct protection_domain, iop);
 127         unsigned long flags;
 128         bool ret = true;
 129         u64 *pte;
 130
 131         pte = iommu_alloc_page_node(cfg->amd.nid, gfp);
 132         if (!pte)
 133                 return false;
 134
 135         spin_lock_irqsave(&domain->lock, flags);
 136
 137         if (address <= PM_LEVEL_SIZE(pgtable->mode) &&
 138             pgtable->mode - 1 >= page_size_level)
 139                 goto out;
 140
 141         ret = false;
 142         if (WARN_ON_ONCE(pgtable->mode == PAGE_MODE_6_LEVEL))
 143                 goto out;
 144
 145         *pte = PM_LEVEL_PDE(pgtable->mode, iommu_virt_to_phys(pgtable->root));
 146
 147         pgtable->root  = pte;
 148         pgtable->mode += 1;
 149         amd_iommu_update_and_flush_device_table(domain);
 150
 151         pte = NULL;
 152         ret = true;
 153
 154 out:
 155         spin_unlock_irqrestore(&domain->lock, flags);
 156         iommu_free_page(pte);
 157
 158         return ret;
 159 }
 160
 161 static u64 *alloc_pte(struct amd_io_pgtable *pgtable,
 162                       unsigned long address,
 163                       unsigned long page_size,
 164                       u64 **pte_page,
 165                       gfp_t gfp,
 166                       bool *updated)
 167 {
 168         unsigned long last_addr = address + (page_size - 1);
 169         struct io_pgtable_cfg *cfg = &pgtable->pgtbl.cfg;
 170         int level, end_lvl;
 171         u64 *pte, *page;
 172
 173         BUG_ON(!is_power_of_2(page_size));
 174
 175         while (last_addr > PM_LEVEL_SIZE(pgtable->mode) ||
 176                pgtable->mode - 1 < PAGE_SIZE_LEVEL(page_size)) {
 177                 /*
 178                  * Return an error if there is no memory to update the
 179                  * page-table.
 180                  */
 181                 if (!increase_address_space(pgtable, last_addr,
 182                                             PAGE_SIZE_LEVEL(page_size), gfp))
 183                         return NULL;
 184         }
 185
 186
 187         level   = pgtable->mode - 1;
 188         pte     = &pgtable->root[PM_LEVEL_INDEX(level, address)];
 189         address = PAGE_SIZE_ALIGN(address, page_size);
 190         end_lvl = PAGE_SIZE_LEVEL(page_size);
 191
 192         while (level > end_lvl) {
 193                 u64 __pte, __npte;
 194                 int pte_level;
 195
 196                 __pte     = *pte;
 197                 pte_level = PM_PTE_LEVEL(__pte);
 198
 199                 /*
 200                  * If we replace a series of large PTEs, we need
 201                  * to tear down all of them.
 202                  */
 203                 if (IOMMU_PTE_PRESENT(__pte) &&
 204                     pte_level == PAGE_MODE_7_LEVEL) {
 205                         unsigned long count, i;
 206                         u64 *lpte;
 207
 208                         lpte = first_pte_l7(pte, NULL, &count);
 209
 210                         /*
 211                          * Unmap the replicated PTEs that still match the
 212                          * original large mapping
 213                          */
 214                         for (i = 0; i < count; ++i)
 215                                 cmpxchg64(&lpte[i], __pte, 0ULL);
 216
 217                         *updated = true;
 218                         continue;
 219                 }
 220
 221                 if (!IOMMU_PTE_PRESENT(__pte) ||
 222                     pte_level == PAGE_MODE_NONE) {
 223                         page = iommu_alloc_page_node(cfg->amd.nid, gfp);
 224
 225                         if (!page)
 226                                 return NULL;
 227
 228                         __npte = PM_LEVEL_PDE(level, iommu_virt_to_phys(page));
 229
 230                         /* pte could have been changed somewhere. */
 231                         if (!try_cmpxchg64(pte, &__pte, __npte))
 232                                 iommu_free_page(page);
 233                         else if (IOMMU_PTE_PRESENT(__pte))
 234                                 *updated = true;
 235
 236                         continue;
 237                 }
 238
 239                 /* No level skipping support yet */
 240                 if (pte_level != level)
 241                         return NULL;
 242
 243                 level -= 1;
 244
 245                 pte = IOMMU_PTE_PAGE(__pte);
 246
 247                 if (pte_page && level == end_lvl)
 248                         *pte_page = pte;
 249
 250                 pte = &pte[PM_LEVEL_INDEX(level, address)];
 251         }
 252
 253         return pte;
 254 }
 255
 256 /*
 257  * This function checks if there is a PTE for a given dma address. If
 258  * there is one, it returns the pointer to it.
 259  */
 260 static u64 *fetch_pte(struct amd_io_pgtable *pgtable,
 261                       unsigned long address,
 262                       unsigned long *page_size)
 263 {
 264         int level;
 265         u64 *pte;
 266
 267         *page_size = 0;
 268
 269         if (address > PM_LEVEL_SIZE(pgtable->mode))
 270                 return NULL;
 271
 272         level      =  pgtable->mode - 1;
 273         pte        = &pgtable->root[PM_LEVEL_INDEX(level, address)];
 274         *page_size =  PTE_LEVEL_PAGE_SIZE(level);
 275
 276         while (level > 0) {
 277
 278                 /* Not Present */
 279                 if (!IOMMU_PTE_PRESENT(*pte))
 280                         return NULL;
 281
 282                 /* Large PTE */
 283                 if (PM_PTE_LEVEL(*pte) == PAGE_MODE_7_LEVEL ||
 284                     PM_PTE_LEVEL(*pte) == PAGE_MODE_NONE)
 285                         break;
 286
 287                 /* No level skipping support yet */
 288                 if (PM_PTE_LEVEL(*pte) != level)
 289                         return NULL;
 290
 291                 level -= 1;
 292
 293                 /* Walk to the next level */
 294                 pte        = IOMMU_PTE_PAGE(*pte);
 295                 pte        = &pte[PM_LEVEL_INDEX(level, address)];
 296                 *page_size = PTE_LEVEL_PAGE_SIZE(level);
 297         }
 298
 299         /*
 300          * If we have a series of large PTEs, make
 301          * sure to return a pointer to the first one.
 302          */
 303         if (PM_PTE_LEVEL(*pte) == PAGE_MODE_7_LEVEL)
 304                 pte = first_pte_l7(pte, page_size, NULL);
 305
 306         return pte;
 307 }
 308
 309 static void free_clear_pte(u64 *pte, u64 pteval, struct list_head *freelist)
 310 {
 311         u64 *pt;
 312         int mode;
 313
 314         while (!try_cmpxchg64(pte, &pteval, 0))
 315                 pr_warn("AMD-Vi: IOMMU pte changed since we read it\n");
 316
 317         if (!IOMMU_PTE_PRESENT(pteval))
 318                 return;
 319
 320         pt   = IOMMU_PTE_PAGE(pteval);
 321         mode = IOMMU_PTE_MODE(pteval);
 322
 323         free_sub_pt(pt, mode, freelist);
 324 }
 325
 326 /*
 327  * Generic mapping functions. It maps a physical address into a DMA
 328  * address space. It allocates the page table pages if necessary.
 329  * In the future it can be extended to a generic mapping function
 330  * supporting all features of AMD IOMMU page tables like level skipping
 331  * and full 64 bit address spaces.
 332  */
 333 static int iommu_v1_map_pages(struct io_pgtable_ops *ops, unsigned long iova,
 334                               phys_addr_t paddr, size_t pgsize, size_t pgcount,
 335                               int prot, gfp_t gfp, size_t *mapped)
 336 {
 337         struct amd_io_pgtable *pgtable = io_pgtable_ops_to_data(ops);
 338         LIST_HEAD(freelist);
 339         bool updated = false;
 340         u64 __pte, *pte;
 341         int ret, i, count;
 342         size_t size = pgcount << __ffs(pgsize);
 343         unsigned long o_iova = iova;
 344
 345         BUG_ON(!IS_ALIGNED(iova, pgsize));
 346         BUG_ON(!IS_ALIGNED(paddr, pgsize));
 347
 348         ret = -EINVAL;
 349         if (!(prot & IOMMU_PROT_MASK))
 350                 goto out;
 351
 352         while (pgcount > 0) {
 353                 count = PAGE_SIZE_PTE_COUNT(pgsize);
 354                 pte   = alloc_pte(pgtable, iova, pgsize, NULL, gfp, &updated);
 355
 356                 ret = -ENOMEM;
 357                 if (!pte)
 358                         goto out;
 359
 360                 for (i = 0; i < count; ++i)
 361                         free_clear_pte(&pte[i], pte[i], &freelist);
 362
 363                 if (!list_empty(&freelist))
 364                         updated = true;
 365
 366                 if (count > 1) {
 367                         __pte = PAGE_SIZE_PTE(__sme_set(paddr), pgsize);
 368                         __pte |= PM_LEVEL_ENC(7) | IOMMU_PTE_PR | IOMMU_PTE_FC;
 369                 } else
 370                         __pte = __sme_set(paddr) | IOMMU_PTE_PR | IOMMU_PTE_FC;
 371
 372                 if (prot & IOMMU_PROT_IR)
 373                         __pte |= IOMMU_PTE_IR;
 374                 if (prot & IOMMU_PROT_IW)
 375                         __pte |= IOMMU_PTE_IW;
 376
 377                 for (i = 0; i < count; ++i)
 378                         pte[i] = __pte;
 379
 380                 iova  += pgsize;
 381                 paddr += pgsize;
 382                 pgcount--;
 383                 if (mapped)
 384                         *mapped += pgsize;
 385         }
 386
 387         ret = 0;
 388
 389 out:
 390         if (updated) {
 391                 struct protection_domain *dom = io_pgtable_ops_to_domain(ops);
 392                 unsigned long flags;
 393
 394                 spin_lock_irqsave(&dom->lock, flags);
 395                 /*
 396                  * Flush domain TLB(s) and wait for completion. Any Device-Table
 397                  * Updates and flushing already happened in
 398                  * increase_address_space().
 399                  */
 400                 amd_iommu_domain_flush_pages(dom, o_iova, size);
 401                 spin_unlock_irqrestore(&dom->lock, flags);
 402         }
 403
 404         /* Everything flushed out, free pages now */
 405         iommu_put_pages_list(&freelist);
 406
 407         return ret;
 408 }
 409
 410 static unsigned long iommu_v1_unmap_pages(struct io_pgtable_ops *ops,
 411                                           unsigned long iova,
 412                                           size_t pgsize, size_t pgcount,
 413                                           struct iommu_iotlb_gather *gather)
 414 {
 415         struct amd_io_pgtable *pgtable = io_pgtable_ops_to_data(ops);
 416         unsigned long long unmapped;
 417         unsigned long unmap_size;
 418         u64 *pte;
 419         size_t size = pgcount << __ffs(pgsize);
 420
 421         BUG_ON(!is_power_of_2(pgsize));
 422
 423         unmapped = 0;
 424
 425         while (unmapped < size) {
 426                 pte = fetch_pte(pgtable, iova, &unmap_size);
 427                 if (pte) {
 428                         int i, count;
 429
 430                         count = PAGE_SIZE_PTE_COUNT(unmap_size);
 431                         for (i = 0; i < count; i++)
 432                                 pte[i] = 0ULL;
 433                 } else {
 434                         return unmapped;
 435                 }
 436
 437                 iova = (iova & ~(unmap_size - 1)) + unmap_size;
 438                 unmapped += unmap_size;
 439         }
 440
 441         return unmapped;
 442 }
 443
 444 static phys_addr_t iommu_v1_iova_to_phys(struct io_pgtable_ops *ops, unsigned long iova)
 445 {
 446         struct amd_io_pgtable *pgtable = io_pgtable_ops_to_data(ops);
 447         unsigned long offset_mask, pte_pgsize;
 448         u64 *pte, __pte;
 449
 450         pte = fetch_pte(pgtable, iova, &pte_pgsize);
 451
 452         if (!pte || !IOMMU_PTE_PRESENT(*pte))
 453                 return 0;
 454
 455         offset_mask = pte_pgsize - 1;
 456         __pte       = __sme_clr(*pte & PM_ADDR_MASK);
 457
 458         return (__pte & ~offset_mask) | (iova & offset_mask);
 459 }
 460
 461 static bool pte_test_and_clear_dirty(u64 *ptep, unsigned long size,
 462                                      unsigned long flags)
 463 {
 464         bool test_only = flags & IOMMU_DIRTY_NO_CLEAR;
 465         bool dirty = false;
 466         int i, count;
 467
 468         /*
 469          * 2.2.3.2 Host Dirty Support
 470          * When a non-default page size is used , software must OR the
 471          * Dirty bits in all of the replicated host PTEs used to map
 472          * the page. The IOMMU does not guarantee the Dirty bits are
 473          * set in all of the replicated PTEs. Any portion of the page
 474          * may have been written even if the Dirty bit is set in only
 475          * one of the replicated PTEs.
 476          */
 477         count = PAGE_SIZE_PTE_COUNT(size);
 478         for (i = 0; i < count && test_only; i++) {
 479                 if (test_bit(IOMMU_PTE_HD_BIT, (unsigned long *)&ptep[i])) {
 480                         dirty = true;
 481                         break;
 482                 }
 483         }
 484
 485         for (i = 0; i < count && !test_only; i++) {
 486                 if (test_and_clear_bit(IOMMU_PTE_HD_BIT,
 487                                        (unsigned long *)&ptep[i])) {
 488                         dirty = true;
 489                 }
 490         }
 491
 492         return dirty;
 493 }
 494
 495 static int iommu_v1_read_and_clear_dirty(struct io_pgtable_ops *ops,
 496                                          unsigned long iova, size_t size,
 497                                          unsigned long flags,
 498                                          struct iommu_dirty_bitmap *dirty)
 499 {
 500         struct amd_io_pgtable *pgtable = io_pgtable_ops_to_data(ops);
 501         unsigned long end = iova + size - 1;
 502
 503         do {
 504                 unsigned long pgsize = 0;
 505                 u64 *ptep, pte;
 506
 507                 ptep = fetch_pte(pgtable, iova, &pgsize);
 508                 if (ptep)
 509                         pte = READ_ONCE(*ptep);
 510                 if (!ptep || !IOMMU_PTE_PRESENT(pte)) {
 511                         pgsize = pgsize ?: PTE_LEVEL_PAGE_SIZE(0);
 512                         iova += pgsize;
 513                         continue;
 514                 }
 515
 516                 /*
 517                  * Mark the whole IOVA range as dirty even if only one of
 518                  * the replicated PTEs were marked dirty.
 519                  */
 520                 if (pte_test_and_clear_dirty(ptep, pgsize, flags))
 521                         iommu_dirty_bitmap_record(dirty, iova, pgsize);
 522                 iova += pgsize;
 523         } while (iova < end);
 524
 525         return 0;
 526 }
 527
 528 /*
 529  * ----------------------------------------------------
 530  */
 531 static void v1_free_pgtable(struct io_pgtable *iop)
 532 {
 533         struct amd_io_pgtable *pgtable = container_of(iop, struct amd_io_pgtable, pgtbl);
 534         LIST_HEAD(freelist);
 535
 536         if (pgtable->mode == PAGE_MODE_NONE)
 537                 return;
 538
 539         /* Page-table is not visible to IOMMU anymore, so free it */
 540         BUG_ON(pgtable->mode < PAGE_MODE_NONE ||
 541                pgtable->mode > PAGE_MODE_6_LEVEL);
 542
 543         free_sub_pt(pgtable->root, pgtable->mode, &freelist);
 544         iommu_put_pages_list(&freelist);
 545 }
 546
 547 static struct io_pgtable *v1_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
 548 {
 549         struct amd_io_pgtable *pgtable = io_pgtable_cfg_to_data(cfg);
 550
 551         pgtable->root = iommu_alloc_page_node(cfg->amd.nid, GFP_KERNEL);
 552         if (!pgtable->root)
 553                 return NULL;
 554         pgtable->mode = PAGE_MODE_3_LEVEL;
 555
 556         cfg->pgsize_bitmap  = amd_iommu_pgsize_bitmap;
 557         cfg->ias            = IOMMU_IN_ADDR_BIT_SIZE;
 558         cfg->oas            = IOMMU_OUT_ADDR_BIT_SIZE;
 559
 560         pgtable->pgtbl.ops.map_pages    = iommu_v1_map_pages;
 561         pgtable->pgtbl.ops.unmap_pages  = iommu_v1_unmap_pages;
 562         pgtable->pgtbl.ops.iova_to_phys = iommu_v1_iova_to_phys;
 563         pgtable->pgtbl.ops.read_and_clear_dirty = iommu_v1_read_and_clear_dirty;
 564
 565         return &pgtable->pgtbl;
 566 }
 567
 568 struct io_pgtable_init_fns io_pgtable_amd_iommu_v1_init_fns = {
 569         .alloc  = v1_alloc_pgtable,
 570         .free   = v1_free_pgtable,
 571 };