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
  26 static void v1_tlb_flush_all(void *cookie)
  27 {
  28 }
  29
  30 static void v1_tlb_flush_walk(unsigned long iova, size_t size,
  31                                   size_t granule, void *cookie)
  32 {
  33 }
  34
  35 static void v1_tlb_add_page(struct iommu_iotlb_gather *gather,
  36                                          unsigned long iova, size_t granule,
  37                                          void *cookie)
  38 {
  39 }
  40
  41 static const struct iommu_flush_ops v1_flush_ops = {
  42         .tlb_flush_all  = v1_tlb_flush_all,
  43         .tlb_flush_walk = v1_tlb_flush_walk,
  44         .tlb_add_page   = v1_tlb_add_page,
  45 };
  46
  47 /*
  48  * Helper function to get the first pte of a large mapping
  49  */
  50 static u64 *first_pte_l7(u64 *pte, unsigned long *page_size,
  51                          unsigned long *count)
  52 {
  53         unsigned long pte_mask, pg_size, cnt;
  54         u64 *fpte;
  55
  56         pg_size  = PTE_PAGE_SIZE(*pte);
  57         cnt      = PAGE_SIZE_PTE_COUNT(pg_size);
  58         pte_mask = ~((cnt << 3) - 1);
  59         fpte     = (u64 *)(((unsigned long)pte) & pte_mask);
  60
  61         if (page_size)
  62                 *page_size = pg_size;
  63
  64         if (count)
  65                 *count = cnt;
  66
  67         return fpte;
  68 }
  69
  70 /****************************************************************************
  71  *
  72  * The functions below are used the create the page table mappings for
  73  * unity mapped regions.
  74  *
  75  ****************************************************************************/
  76
  77 static void free_pt_page(u64 *pt, struct list_head *freelist)
  78 {
  79         struct page *p = virt_to_page(pt);
  80
  81         list_add_tail(&p->lru, freelist);
  82 }
  83
  84 static void free_pt_lvl(u64 *pt, struct list_head *freelist, int lvl)
  85 {
  86         u64 *p;
  87         int i;
  88
  89         for (i = 0; i < 512; ++i) {
  90                 /* PTE present? */
  91                 if (!IOMMU_PTE_PRESENT(pt[i]))
  92                         continue;
  93
  94                 /* Large PTE? */
  95                 if (PM_PTE_LEVEL(pt[i]) == 0 ||
  96                     PM_PTE_LEVEL(pt[i]) == 7)
  97                         continue;
  98
  99                 /*
 100                  * Free the next level. No need to look at l1 tables here since
 101                  * they can only contain leaf PTEs; just free them directly.
 102                  */
 103                 p = IOMMU_PTE_PAGE(pt[i]);
 104                 if (lvl > 2)
 105                         free_pt_lvl(p, freelist, lvl - 1);
 106                 else
 107                         free_pt_page(p, freelist);
 108         }
 109
 110         free_pt_page(pt, freelist);
 111 }
 112
 113 static void free_sub_pt(u64 *root, int mode, struct list_head *freelist)
 114 {
 115         switch (mode) {
 116         case PAGE_MODE_NONE:
 117         case PAGE_MODE_7_LEVEL:
 118                 break;
 119         case PAGE_MODE_1_LEVEL:
 120                 free_pt_page(root, freelist);
 121                 break;
 122         case PAGE_MODE_2_LEVEL:
 123         case PAGE_MODE_3_LEVEL:
 124         case PAGE_MODE_4_LEVEL:
 125         case PAGE_MODE_5_LEVEL:
 126         case PAGE_MODE_6_LEVEL:
 127                 free_pt_lvl(root, freelist, mode);
 128                 break;
 129         default:
 130                 BUG();
 131         }
 132 }
 133
 134 void amd_iommu_domain_set_pgtable(struct protection_domain *domain,
 135                                   u64 *root, int mode)
 136 {
 137         u64 pt_root;
 138
 139         /* lowest 3 bits encode pgtable mode */
 140         pt_root = mode & 7;
 141         pt_root |= (u64)root;
 142
 143         amd_iommu_domain_set_pt_root(domain, pt_root);
 144 }
 145
 146 /*
 147  * This function is used to add another level to an IO page table. Adding
 148  * another level increases the size of the address space by 9 bits to a size up
 149  * to 64 bits.
 150  */
 151 static bool increase_address_space(struct protection_domain *domain,
 152                                    unsigned long address,
 153                                    gfp_t gfp)
 154 {
 155         unsigned long flags;
 156         bool ret = true;
 157         u64 *pte;
 158
 159         pte = (void *)get_zeroed_page(gfp);
 160         if (!pte)
 161                 return false;
 162
 163         spin_lock_irqsave(&domain->lock, flags);
 164
 165         if (address <= PM_LEVEL_SIZE(domain->iop.mode))
 166                 goto out;
 167
 168         ret = false;
 169         if (WARN_ON_ONCE(domain->iop.mode == PAGE_MODE_6_LEVEL))
 170                 goto out;
 171
 172         *pte = PM_LEVEL_PDE(domain->iop.mode, iommu_virt_to_phys(domain->iop.root));
 173
 174         domain->iop.root  = pte;
 175         domain->iop.mode += 1;
 176         amd_iommu_update_and_flush_device_table(domain);
 177         amd_iommu_domain_flush_complete(domain);
 178
 179         /*
 180          * Device Table needs to be updated and flushed before the new root can
 181          * be published.
 182          */
 183         amd_iommu_domain_set_pgtable(domain, pte, domain->iop.mode);
 184
 185         pte = NULL;
 186         ret = true;
 187
 188 out:
 189         spin_unlock_irqrestore(&domain->lock, flags);
 190         free_page((unsigned long)pte);
 191
 192         return ret;
 193 }
 194
 195 static u64 *alloc_pte(struct protection_domain *domain,
 196                       unsigned long address,
 197                       unsigned long page_size,
 198                       u64 **pte_page,
 199                       gfp_t gfp,
 200                       bool *updated)
 201 {
 202         int level, end_lvl;
 203         u64 *pte, *page;
 204
 205         BUG_ON(!is_power_of_2(page_size));
 206
 207         while (address > PM_LEVEL_SIZE(domain->iop.mode)) {
 208                 /*
 209                  * Return an error if there is no memory to update the
 210                  * page-table.
 211                  */
 212                 if (!increase_address_space(domain, address, gfp))
 213                         return NULL;
 214         }
 215
 216
 217         level   = domain->iop.mode - 1;
 218         pte     = &domain->iop.root[PM_LEVEL_INDEX(level, address)];
 219         address = PAGE_SIZE_ALIGN(address, page_size);
 220         end_lvl = PAGE_SIZE_LEVEL(page_size);
 221
 222         while (level > end_lvl) {
 223                 u64 __pte, __npte;
 224                 int pte_level;
 225
 226                 __pte     = *pte;
 227                 pte_level = PM_PTE_LEVEL(__pte);
 228
 229                 /*
 230                  * If we replace a series of large PTEs, we need
 231                  * to tear down all of them.
 232                  */
 233                 if (IOMMU_PTE_PRESENT(__pte) &&
 234                     pte_level == PAGE_MODE_7_LEVEL) {
 235                         unsigned long count, i;
 236                         u64 *lpte;
 237
 238                         lpte = first_pte_l7(pte, NULL, &count);
 239
 240                         /*
 241                          * Unmap the replicated PTEs that still match the
 242                          * original large mapping
 243                          */
 244                         for (i = 0; i < count; ++i)
 245                                 cmpxchg64(&lpte[i], __pte, 0ULL);
 246
 247                         *updated = true;
 248                         continue;
 249                 }
 250
 251                 if (!IOMMU_PTE_PRESENT(__pte) ||
 252                     pte_level == PAGE_MODE_NONE) {
 253                         page = (u64 *)get_zeroed_page(gfp);
 254
 255                         if (!page)
 256                                 return NULL;
 257
 258                         __npte = PM_LEVEL_PDE(level, iommu_virt_to_phys(page));
 259
 260                         /* pte could have been changed somewhere. */
 261                         if (!try_cmpxchg64(pte, &__pte, __npte))
 262                                 free_page((unsigned long)page);
 263                         else if (IOMMU_PTE_PRESENT(__pte))
 264                                 *updated = true;
 265
 266                         continue;
 267                 }
 268
 269                 /* No level skipping support yet */
 270                 if (pte_level != level)
 271                         return NULL;
 272
 273                 level -= 1;
 274
 275                 pte = IOMMU_PTE_PAGE(__pte);
 276
 277                 if (pte_page && level == end_lvl)
 278                         *pte_page = pte;
 279
 280                 pte = &pte[PM_LEVEL_INDEX(level, address)];
 281         }
 282
 283         return pte;
 284 }
 285
 286 /*
 287  * This function checks if there is a PTE for a given dma address. If
 288  * there is one, it returns the pointer to it.
 289  */
 290 static u64 *fetch_pte(struct amd_io_pgtable *pgtable,
 291                       unsigned long address,
 292                       unsigned long *page_size)
 293 {
 294         int level;
 295         u64 *pte;
 296
 297         *page_size = 0;
 298
 299         if (address > PM_LEVEL_SIZE(pgtable->mode))
 300                 return NULL;
 301
 302         level      =  pgtable->mode - 1;
 303         pte        = &pgtable->root[PM_LEVEL_INDEX(level, address)];
 304         *page_size =  PTE_LEVEL_PAGE_SIZE(level);
 305
 306         while (level > 0) {
 307
 308                 /* Not Present */
 309                 if (!IOMMU_PTE_PRESENT(*pte))
 310                         return NULL;
 311
 312                 /* Large PTE */
 313                 if (PM_PTE_LEVEL(*pte) == 7 ||
 314                     PM_PTE_LEVEL(*pte) == 0)
 315                         break;
 316
 317                 /* No level skipping support yet */
 318                 if (PM_PTE_LEVEL(*pte) != level)
 319                         return NULL;
 320
 321                 level -= 1;
 322
 323                 /* Walk to the next level */
 324                 pte        = IOMMU_PTE_PAGE(*pte);
 325                 pte        = &pte[PM_LEVEL_INDEX(level, address)];
 326                 *page_size = PTE_LEVEL_PAGE_SIZE(level);
 327         }
 328
 329         /*
 330          * If we have a series of large PTEs, make
 331          * sure to return a pointer to the first one.
 332          */
 333         if (PM_PTE_LEVEL(*pte) == PAGE_MODE_7_LEVEL)
 334                 pte = first_pte_l7(pte, page_size, NULL);
 335
 336         return pte;
 337 }
 338
 339 static void free_clear_pte(u64 *pte, u64 pteval, struct list_head *freelist)
 340 {
 341         u64 *pt;
 342         int mode;
 343
 344         while (!try_cmpxchg64(pte, &pteval, 0))
 345                 pr_warn("AMD-Vi: IOMMU pte changed since we read it\n");
 346
 347         if (!IOMMU_PTE_PRESENT(pteval))
 348                 return;
 349
 350         pt   = IOMMU_PTE_PAGE(pteval);
 351         mode = IOMMU_PTE_MODE(pteval);
 352
 353         free_sub_pt(pt, mode, freelist);
 354 }
 355
 356 /*
 357  * Generic mapping functions. It maps a physical address into a DMA
 358  * address space. It allocates the page table pages if necessary.
 359  * In the future it can be extended to a generic mapping function
 360  * supporting all features of AMD IOMMU page tables like level skipping
 361  * and full 64 bit address spaces.
 362  */
 363 static int iommu_v1_map_page(struct io_pgtable_ops *ops, unsigned long iova,
 364                           phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
 365 {
 366         struct protection_domain *dom = io_pgtable_ops_to_domain(ops);
 367         LIST_HEAD(freelist);
 368         bool updated = false;
 369         u64 __pte, *pte;
 370         int ret, i, count;
 371
 372         BUG_ON(!IS_ALIGNED(iova, size));
 373         BUG_ON(!IS_ALIGNED(paddr, size));
 374
 375         ret = -EINVAL;
 376         if (!(prot & IOMMU_PROT_MASK))
 377                 goto out;
 378
 379         count = PAGE_SIZE_PTE_COUNT(size);
 380         pte   = alloc_pte(dom, iova, size, NULL, gfp, &updated);
 381
 382         ret = -ENOMEM;
 383         if (!pte)
 384                 goto out;
 385
 386         for (i = 0; i < count; ++i)
 387                 free_clear_pte(&pte[i], pte[i], &freelist);
 388
 389         if (!list_empty(&freelist))
 390                 updated = true;
 391
 392         if (count > 1) {
 393                 __pte = PAGE_SIZE_PTE(__sme_set(paddr), size);
 394                 __pte |= PM_LEVEL_ENC(7) | IOMMU_PTE_PR | IOMMU_PTE_FC;
 395         } else
 396                 __pte = __sme_set(paddr) | IOMMU_PTE_PR | IOMMU_PTE_FC;
 397
 398         if (prot & IOMMU_PROT_IR)
 399                 __pte |= IOMMU_PTE_IR;
 400         if (prot & IOMMU_PROT_IW)
 401                 __pte |= IOMMU_PTE_IW;
 402
 403         for (i = 0; i < count; ++i)
 404                 pte[i] = __pte;
 405
 406         ret = 0;
 407
 408 out:
 409         if (updated) {
 410                 unsigned long flags;
 411
 412                 spin_lock_irqsave(&dom->lock, flags);
 413                 /*
 414                  * Flush domain TLB(s) and wait for completion. Any Device-Table
 415                  * Updates and flushing already happened in
 416                  * increase_address_space().
 417                  */
 418                 amd_iommu_domain_flush_tlb_pde(dom);
 419                 amd_iommu_domain_flush_complete(dom);
 420                 spin_unlock_irqrestore(&dom->lock, flags);
 421         }
 422
 423         /* Everything flushed out, free pages now */
 424         put_pages_list(&freelist);
 425
 426         return ret;
 427 }
 428
 429 static unsigned long iommu_v1_unmap_page(struct io_pgtable_ops *ops,
 430                                       unsigned long iova,
 431                                       size_t size,
 432                                       struct iommu_iotlb_gather *gather)
 433 {
 434         struct amd_io_pgtable *pgtable = io_pgtable_ops_to_data(ops);
 435         unsigned long long unmapped;
 436         unsigned long unmap_size;
 437         u64 *pte;
 438
 439         BUG_ON(!is_power_of_2(size));
 440
 441         unmapped = 0;
 442
 443         while (unmapped < size) {
 444                 pte = fetch_pte(pgtable, iova, &unmap_size);
 445                 if (pte) {
 446                         int i, count;
 447
 448                         count = PAGE_SIZE_PTE_COUNT(unmap_size);
 449                         for (i = 0; i < count; i++)
 450                                 pte[i] = 0ULL;
 451                 }
 452
 453                 iova = (iova & ~(unmap_size - 1)) + unmap_size;
 454                 unmapped += unmap_size;
 455         }
 456
 457         BUG_ON(unmapped && !is_power_of_2(unmapped));
 458
 459         return unmapped;
 460 }
 461
 462 static phys_addr_t iommu_v1_iova_to_phys(struct io_pgtable_ops *ops, unsigned long iova)
 463 {
 464         struct amd_io_pgtable *pgtable = io_pgtable_ops_to_data(ops);
 465         unsigned long offset_mask, pte_pgsize;
 466         u64 *pte, __pte;
 467
 468         pte = fetch_pte(pgtable, iova, &pte_pgsize);
 469
 470         if (!pte || !IOMMU_PTE_PRESENT(*pte))
 471                 return 0;
 472
 473         offset_mask = pte_pgsize - 1;
 474         __pte       = __sme_clr(*pte & PM_ADDR_MASK);
 475
 476         return (__pte & ~offset_mask) | (iova & offset_mask);
 477 }
 478
 479 /*
 480  * ----------------------------------------------------
 481  */
 482 static void v1_free_pgtable(struct io_pgtable *iop)
 483 {
 484         struct amd_io_pgtable *pgtable = container_of(iop, struct amd_io_pgtable, iop);
 485         struct protection_domain *dom;
 486         LIST_HEAD(freelist);
 487
 488         if (pgtable->mode == PAGE_MODE_NONE)
 489                 return;
 490
 491         dom = container_of(pgtable, struct protection_domain, iop);
 492
 493         /* Page-table is not visible to IOMMU anymore, so free it */
 494         BUG_ON(pgtable->mode < PAGE_MODE_NONE ||
 495                pgtable->mode > PAGE_MODE_6_LEVEL);
 496
 497         free_sub_pt(pgtable->root, pgtable->mode, &freelist);
 498
 499         /* Update data structure */
 500         amd_iommu_domain_clr_pt_root(dom);
 501
 502         /* Make changes visible to IOMMUs */
 503         amd_iommu_domain_update(dom);
 504
 505         put_pages_list(&freelist);
 506 }
 507
 508 static struct io_pgtable *v1_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
 509 {
 510         struct amd_io_pgtable *pgtable = io_pgtable_cfg_to_data(cfg);
 511
 512         cfg->pgsize_bitmap  = AMD_IOMMU_PGSIZES,
 513         cfg->ias            = IOMMU_IN_ADDR_BIT_SIZE,
 514         cfg->oas            = IOMMU_OUT_ADDR_BIT_SIZE,
 515         cfg->tlb            = &v1_flush_ops;
 516
 517         pgtable->iop.ops.map          = iommu_v1_map_page;
 518         pgtable->iop.ops.unmap        = iommu_v1_unmap_page;
 519         pgtable->iop.ops.iova_to_phys = iommu_v1_iova_to_phys;
 520
 521         return &pgtable->iop;
 522 }
 523
 524 struct io_pgtable_init_fns io_pgtable_amd_iommu_v1_init_fns = {
 525         .alloc  = v1_alloc_pgtable,
 526         .free   = v1_free_pgtable,
 527 };