drivers/vfio/vfio_iommu_spapr_tce.c

   1 /*
   2  * VFIO: IOMMU DMA mapping support for TCE on POWER
   3  *
   4  * Copyright (C) 2013 IBM Corp.  All rights reserved.
   5  *     Author: Alexey Kardashevskiy <[email protected]>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * Derived from original vfio_iommu_type1.c:
  12  * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
  13  *     Author: Alex Williamson <[email protected]>
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/pci.h>
  18 #include <linux/slab.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/err.h>
  21 #include <linux/vfio.h>
  22 #include <linux/vmalloc.h>
  23 #include <asm/iommu.h>
  24 #include <asm/tce.h>
  25 #include <asm/mmu_context.h>
  26
  27 #define DRIVER_VERSION  "0.1"
  28 #define DRIVER_AUTHOR   "[email protected]"
  29 #define DRIVER_DESC     "VFIO IOMMU SPAPR TCE"
  30
  31 static void tce_iommu_detach_group(void *iommu_data,
  32                 struct iommu_group *iommu_group);
  33
  34 static long try_increment_locked_vm(long npages)
  35 {
  36         long ret = 0, locked, lock_limit;
  37
  38         if (!current || !current->mm)
  39                 return -ESRCH; /* process exited */
  40
  41         if (!npages)
  42                 return 0;
  43
  44         down_write(&current->mm->mmap_sem);
  45         locked = current->mm->locked_vm + npages;
  46         lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
  47         if (locked > lock_limit && !capable(CAP_IPC_LOCK))
  48                 ret = -ENOMEM;
  49         else
  50                 current->mm->locked_vm += npages;
  51
  52         pr_debug("[%d] RLIMIT_MEMLOCK +%ld %ld/%ld%s\n", current->pid,
  53                         npages << PAGE_SHIFT,
  54                         current->mm->locked_vm << PAGE_SHIFT,
  55                         rlimit(RLIMIT_MEMLOCK),
  56                         ret ? " - exceeded" : "");
  57
  58         up_write(&current->mm->mmap_sem);
  59
  60         return ret;
  61 }
  62
  63 static void decrement_locked_vm(long npages)
  64 {
  65         if (!current || !current->mm || !npages)
  66                 return; /* process exited */
  67
  68         down_write(&current->mm->mmap_sem);
  69         if (WARN_ON_ONCE(npages > current->mm->locked_vm))
  70                 npages = current->mm->locked_vm;
  71         current->mm->locked_vm -= npages;
  72         pr_debug("[%d] RLIMIT_MEMLOCK -%ld %ld/%ld\n", current->pid,
  73                         npages << PAGE_SHIFT,
  74                         current->mm->locked_vm << PAGE_SHIFT,
  75                         rlimit(RLIMIT_MEMLOCK));
  76         up_write(&current->mm->mmap_sem);
  77 }
  78
  79 /*
  80  * VFIO IOMMU fd for SPAPR_TCE IOMMU implementation
  81  *
  82  * This code handles mapping and unmapping of user data buffers
  83  * into DMA'ble space using the IOMMU
  84  */
  85
  86 struct tce_iommu_group {
  87         struct list_head next;
  88         struct iommu_group *grp;
  89 };
  90
  91 /*
  92  * The container descriptor supports only a single group per container.
  93  * Required by the API as the container is not supplied with the IOMMU group
  94  * at the moment of initialization.
  95  */
  96 struct tce_container {
  97         struct mutex lock;
  98         bool enabled;
  99         bool v2;
 100         unsigned long locked_pages;
 101         struct iommu_table *tables[IOMMU_TABLE_GROUP_MAX_TABLES];
 102         struct list_head group_list;
 103 };
 104
 105 static long tce_iommu_unregister_pages(struct tce_container *container,
 106                 __u64 vaddr, __u64 size)
 107 {
 108         struct mm_iommu_table_group_mem_t *mem;
 109
 110         if ((vaddr & ~PAGE_MASK) || (size & ~PAGE_MASK))
 111                 return -EINVAL;
 112
 113         mem = mm_iommu_find(vaddr, size >> PAGE_SHIFT);
 114         if (!mem)
 115                 return -ENOENT;
 116
 117         return mm_iommu_put(mem);
 118 }
 119
 120 static long tce_iommu_register_pages(struct tce_container *container,
 121                 __u64 vaddr, __u64 size)
 122 {
 123         long ret = 0;
 124         struct mm_iommu_table_group_mem_t *mem = NULL;
 125         unsigned long entries = size >> PAGE_SHIFT;
 126
 127         if ((vaddr & ~PAGE_MASK) || (size & ~PAGE_MASK) ||
 128                         ((vaddr + size) < vaddr))
 129                 return -EINVAL;
 130
 131         ret = mm_iommu_get(vaddr, entries, &mem);
 132         if (ret)
 133                 return ret;
 134
 135         container->enabled = true;
 136
 137         return 0;
 138 }
 139
 140 static long tce_iommu_userspace_view_alloc(struct iommu_table *tbl)
 141 {
 142         unsigned long cb = _ALIGN_UP(sizeof(tbl->it_userspace[0]) *
 143                         tbl->it_size, PAGE_SIZE);
 144         unsigned long *uas;
 145         long ret;
 146
 147         BUG_ON(tbl->it_userspace);
 148
 149         ret = try_increment_locked_vm(cb >> PAGE_SHIFT);
 150         if (ret)
 151                 return ret;
 152
 153         uas = vzalloc(cb);
 154         if (!uas) {
 155                 decrement_locked_vm(cb >> PAGE_SHIFT);
 156                 return -ENOMEM;
 157         }
 158         tbl->it_userspace = uas;
 159
 160         return 0;
 161 }
 162
 163 static void tce_iommu_userspace_view_free(struct iommu_table *tbl)
 164 {
 165         unsigned long cb = _ALIGN_UP(sizeof(tbl->it_userspace[0]) *
 166                         tbl->it_size, PAGE_SIZE);
 167
 168         if (!tbl->it_userspace)
 169                 return;
 170
 171         vfree(tbl->it_userspace);
 172         tbl->it_userspace = NULL;
 173         decrement_locked_vm(cb >> PAGE_SHIFT);
 174 }
 175
 176 static bool tce_page_is_contained(struct page *page, unsigned page_shift)
 177 {
 178         /*
 179          * Check that the TCE table granularity is not bigger than the size of
 180          * a page we just found. Otherwise the hardware can get access to
 181          * a bigger memory chunk that it should.
 182          */
 183         return (PAGE_SHIFT + compound_order(compound_head(page))) >= page_shift;
 184 }
 185
 186 static inline bool tce_groups_attached(struct tce_container *container)
 187 {
 188         return !list_empty(&container->group_list);
 189 }
 190
 191 static long tce_iommu_find_table(struct tce_container *container,
 192                 phys_addr_t ioba, struct iommu_table **ptbl)
 193 {
 194         long i;
 195
 196         for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
 197                 struct iommu_table *tbl = container->tables[i];
 198
 199                 if (tbl) {
 200                         unsigned long entry = ioba >> tbl->it_page_shift;
 201                         unsigned long start = tbl->it_offset;
 202                         unsigned long end = start + tbl->it_size;
 203
 204                         if ((start <= entry) && (entry < end)) {
 205                                 *ptbl = tbl;
 206                                 return i;
 207                         }
 208                 }
 209         }
 210
 211         return -1;
 212 }
 213
 214 static int tce_iommu_find_free_table(struct tce_container *container)
 215 {
 216         int i;
 217
 218         for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
 219                 if (!container->tables[i])
 220                         return i;
 221         }
 222
 223         return -ENOSPC;
 224 }
 225
 226 static int tce_iommu_enable(struct tce_container *container)
 227 {
 228         int ret = 0;
 229         unsigned long locked;
 230         struct iommu_table_group *table_group;
 231         struct tce_iommu_group *tcegrp;
 232
 233         if (!current->mm)
 234                 return -ESRCH; /* process exited */
 235
 236         if (container->enabled)
 237                 return -EBUSY;
 238
 239         /*
 240          * When userspace pages are mapped into the IOMMU, they are effectively
 241          * locked memory, so, theoretically, we need to update the accounting
 242          * of locked pages on each map and unmap.  For powerpc, the map unmap
 243          * paths can be very hot, though, and the accounting would kill
 244          * performance, especially since it would be difficult to impossible
 245          * to handle the accounting in real mode only.
 246          *
 247          * To address that, rather than precisely accounting every page, we
 248          * instead account for a worst case on locked memory when the iommu is
 249          * enabled and disabled.  The worst case upper bound on locked memory
 250          * is the size of the whole iommu window, which is usually relatively
 251          * small (compared to total memory sizes) on POWER hardware.
 252          *
 253          * Also we don't have a nice way to fail on H_PUT_TCE due to ulimits,
 254          * that would effectively kill the guest at random points, much better
 255          * enforcing the limit based on the max that the guest can map.
 256          *
 257          * Unfortunately at the moment it counts whole tables, no matter how
 258          * much memory the guest has. I.e. for 4GB guest and 4 IOMMU groups
 259          * each with 2GB DMA window, 8GB will be counted here. The reason for
 260          * this is that we cannot tell here the amount of RAM used by the guest
 261          * as this information is only available from KVM and VFIO is
 262          * KVM agnostic.
 263          *
 264          * So we do not allow enabling a container without a group attached
 265          * as there is no way to know how much we should increment
 266          * the locked_vm counter.
 267          */
 268         if (!tce_groups_attached(container))
 269                 return -ENODEV;
 270
 271         tcegrp = list_first_entry(&container->group_list,
 272                         struct tce_iommu_group, next);
 273         table_group = iommu_group_get_iommudata(tcegrp->grp);
 274         if (!table_group)
 275                 return -ENODEV;
 276
 277         if (!table_group->tce32_size)
 278                 return -EPERM;
 279
 280         locked = table_group->tce32_size >> PAGE_SHIFT;
 281         ret = try_increment_locked_vm(locked);
 282         if (ret)
 283                 return ret;
 284
 285         container->locked_pages = locked;
 286
 287         container->enabled = true;
 288
 289         return ret;
 290 }
 291
 292 static void tce_iommu_disable(struct tce_container *container)
 293 {
 294         if (!container->enabled)
 295                 return;
 296
 297         container->enabled = false;
 298
 299         if (!current->mm)
 300                 return;
 301
 302         decrement_locked_vm(container->locked_pages);
 303 }
 304
 305 static void *tce_iommu_open(unsigned long arg)
 306 {
 307         struct tce_container *container;
 308
 309         if ((arg != VFIO_SPAPR_TCE_IOMMU) && (arg != VFIO_SPAPR_TCE_v2_IOMMU)) {
 310                 pr_err("tce_vfio: Wrong IOMMU type\n");
 311                 return ERR_PTR(-EINVAL);
 312         }
 313
 314         container = kzalloc(sizeof(*container), GFP_KERNEL);
 315         if (!container)
 316                 return ERR_PTR(-ENOMEM);
 317
 318         mutex_init(&container->lock);
 319         INIT_LIST_HEAD_RCU(&container->group_list);
 320
 321         container->v2 = arg == VFIO_SPAPR_TCE_v2_IOMMU;
 322
 323         return container;
 324 }
 325
 326 static int tce_iommu_clear(struct tce_container *container,
 327                 struct iommu_table *tbl,
 328                 unsigned long entry, unsigned long pages);
 329 static void tce_iommu_free_table(struct iommu_table *tbl);
 330
 331 static void tce_iommu_release(void *iommu_data)
 332 {
 333         struct tce_container *container = iommu_data;
 334         struct iommu_table_group *table_group;
 335         struct tce_iommu_group *tcegrp;
 336         long i;
 337
 338         while (tce_groups_attached(container)) {
 339                 tcegrp = list_first_entry(&container->group_list,
 340                                 struct tce_iommu_group, next);
 341                 table_group = iommu_group_get_iommudata(tcegrp->grp);
 342                 tce_iommu_detach_group(iommu_data, tcegrp->grp);
 343         }
 344
 345         /*
 346          * If VFIO created a table, it was not disposed
 347          * by tce_iommu_detach_group() so do it now.
 348          */
 349         for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
 350                 struct iommu_table *tbl = container->tables[i];
 351
 352                 if (!tbl)
 353                         continue;
 354
 355                 tce_iommu_clear(container, tbl, tbl->it_offset, tbl->it_size);
 356                 tce_iommu_free_table(tbl);
 357         }
 358
 359         tce_iommu_disable(container);
 360         mutex_destroy(&container->lock);
 361
 362         kfree(container);
 363 }
 364
 365 static void tce_iommu_unuse_page(struct tce_container *container,
 366                 unsigned long hpa)
 367 {
 368         struct page *page;
 369
 370         page = pfn_to_page(hpa >> PAGE_SHIFT);
 371         put_page(page);
 372 }
 373
 374 static int tce_iommu_prereg_ua_to_hpa(unsigned long tce, unsigned long size,
 375                 unsigned long *phpa, struct mm_iommu_table_group_mem_t **pmem)
 376 {
 377         long ret = 0;
 378         struct mm_iommu_table_group_mem_t *mem;
 379
 380         mem = mm_iommu_lookup(tce, size);
 381         if (!mem)
 382                 return -EINVAL;
 383
 384         ret = mm_iommu_ua_to_hpa(mem, tce, phpa);
 385         if (ret)
 386                 return -EINVAL;
 387
 388         *pmem = mem;
 389
 390         return 0;
 391 }
 392
 393 static void tce_iommu_unuse_page_v2(struct iommu_table *tbl,
 394                 unsigned long entry)
 395 {
 396         struct mm_iommu_table_group_mem_t *mem = NULL;
 397         int ret;
 398         unsigned long hpa = 0;
 399         unsigned long *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl, entry);
 400
 401         if (!pua || !current || !current->mm)
 402                 return;
 403
 404         ret = tce_iommu_prereg_ua_to_hpa(*pua, IOMMU_PAGE_SIZE(tbl),
 405                         &hpa, &mem);
 406         if (ret)
 407                 pr_debug("%s: tce %lx at #%lx was not cached, ret=%d\n",
 408                                 __func__, *pua, entry, ret);
 409         if (mem)
 410                 mm_iommu_mapped_dec(mem);
 411
 412         *pua = 0;
 413 }
 414
 415 static int tce_iommu_clear(struct tce_container *container,
 416                 struct iommu_table *tbl,
 417                 unsigned long entry, unsigned long pages)
 418 {
 419         unsigned long oldhpa;
 420         long ret;
 421         enum dma_data_direction direction;
 422
 423         for ( ; pages; --pages, ++entry) {
 424                 direction = DMA_NONE;
 425                 oldhpa = 0;
 426                 ret = iommu_tce_xchg(tbl, entry, &oldhpa, &direction);
 427                 if (ret)
 428                         continue;
 429
 430                 if (direction == DMA_NONE)
 431                         continue;
 432
 433                 if (container->v2) {
 434                         tce_iommu_unuse_page_v2(tbl, entry);
 435                         continue;
 436                 }
 437
 438                 tce_iommu_unuse_page(container, oldhpa);
 439         }
 440
 441         return 0;
 442 }
 443
 444 static int tce_iommu_use_page(unsigned long tce, unsigned long *hpa)
 445 {
 446         struct page *page = NULL;
 447         enum dma_data_direction direction = iommu_tce_direction(tce);
 448
 449         if (get_user_pages_fast(tce & PAGE_MASK, 1,
 450                         direction != DMA_TO_DEVICE, &page) != 1)
 451                 return -EFAULT;
 452
 453         *hpa = __pa((unsigned long) page_address(page));
 454
 455         return 0;
 456 }
 457
 458 static long tce_iommu_build(struct tce_container *container,
 459                 struct iommu_table *tbl,
 460                 unsigned long entry, unsigned long tce, unsigned long pages,
 461                 enum dma_data_direction direction)
 462 {
 463         long i, ret = 0;
 464         struct page *page;
 465         unsigned long hpa;
 466         enum dma_data_direction dirtmp;
 467
 468         for (i = 0; i < pages; ++i) {
 469                 unsigned long offset = tce & IOMMU_PAGE_MASK(tbl) & ~PAGE_MASK;
 470
 471                 ret = tce_iommu_use_page(tce, &hpa);
 472                 if (ret)
 473                         break;
 474
 475                 page = pfn_to_page(hpa >> PAGE_SHIFT);
 476                 if (!tce_page_is_contained(page, tbl->it_page_shift)) {
 477                         ret = -EPERM;
 478                         break;
 479                 }
 480
 481                 hpa |= offset;
 482                 dirtmp = direction;
 483                 ret = iommu_tce_xchg(tbl, entry + i, &hpa, &dirtmp);
 484                 if (ret) {
 485                         tce_iommu_unuse_page(container, hpa);
 486                         pr_err("iommu_tce: %s failed ioba=%lx, tce=%lx, ret=%ld\n",
 487                                         __func__, entry << tbl->it_page_shift,
 488                                         tce, ret);
 489                         break;
 490                 }
 491
 492                 if (dirtmp != DMA_NONE)
 493                         tce_iommu_unuse_page(container, hpa);
 494
 495                 tce += IOMMU_PAGE_SIZE(tbl);
 496         }
 497
 498         if (ret)
 499                 tce_iommu_clear(container, tbl, entry, i);
 500
 501         return ret;
 502 }
 503
 504 static long tce_iommu_build_v2(struct tce_container *container,
 505                 struct iommu_table *tbl,
 506                 unsigned long entry, unsigned long tce, unsigned long pages,
 507                 enum dma_data_direction direction)
 508 {
 509         long i, ret = 0;
 510         struct page *page;
 511         unsigned long hpa;
 512         enum dma_data_direction dirtmp;
 513
 514         for (i = 0; i < pages; ++i) {
 515                 struct mm_iommu_table_group_mem_t *mem = NULL;
 516                 unsigned long *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl,
 517                                 entry + i);
 518
 519                 ret = tce_iommu_prereg_ua_to_hpa(tce, IOMMU_PAGE_SIZE(tbl),
 520                                 &hpa, &mem);
 521                 if (ret)
 522                         break;
 523
 524                 page = pfn_to_page(hpa >> PAGE_SHIFT);
 525                 if (!tce_page_is_contained(page, tbl->it_page_shift)) {
 526                         ret = -EPERM;
 527                         break;
 528                 }
 529
 530                 /* Preserve offset within IOMMU page */
 531                 hpa |= tce & IOMMU_PAGE_MASK(tbl) & ~PAGE_MASK;
 532                 dirtmp = direction;
 533
 534                 /* The registered region is being unregistered */
 535                 if (mm_iommu_mapped_inc(mem))
 536                         break;
 537
 538                 ret = iommu_tce_xchg(tbl, entry + i, &hpa, &dirtmp);
 539                 if (ret) {
 540                         /* dirtmp cannot be DMA_NONE here */
 541                         tce_iommu_unuse_page_v2(tbl, entry + i);
 542                         pr_err("iommu_tce: %s failed ioba=%lx, tce=%lx, ret=%ld\n",
 543                                         __func__, entry << tbl->it_page_shift,
 544                                         tce, ret);
 545                         break;
 546                 }
 547
 548                 if (dirtmp != DMA_NONE)
 549                         tce_iommu_unuse_page_v2(tbl, entry + i);
 550
 551                 *pua = tce;
 552
 553                 tce += IOMMU_PAGE_SIZE(tbl);
 554         }
 555
 556         if (ret)
 557                 tce_iommu_clear(container, tbl, entry, i);
 558
 559         return ret;
 560 }
 561
 562 static long tce_iommu_create_table(struct tce_container *container,
 563                         struct iommu_table_group *table_group,
 564                         int num,
 565                         __u32 page_shift,
 566                         __u64 window_size,
 567                         __u32 levels,
 568                         struct iommu_table **ptbl)
 569 {
 570         long ret, table_size;
 571
 572         table_size = table_group->ops->get_table_size(page_shift, window_size,
 573                         levels);
 574         if (!table_size)
 575                 return -EINVAL;
 576
 577         ret = try_increment_locked_vm(table_size >> PAGE_SHIFT);
 578         if (ret)
 579                 return ret;
 580
 581         ret = table_group->ops->create_table(table_group, num,
 582                         page_shift, window_size, levels, ptbl);
 583
 584         WARN_ON(!ret && !(*ptbl)->it_ops->free);
 585         WARN_ON(!ret && ((*ptbl)->it_allocated_size != table_size));
 586
 587         if (!ret && container->v2) {
 588                 ret = tce_iommu_userspace_view_alloc(*ptbl);
 589                 if (ret)
 590                         (*ptbl)->it_ops->free(*ptbl);
 591         }
 592
 593         if (ret)
 594                 decrement_locked_vm(table_size >> PAGE_SHIFT);
 595
 596         return ret;
 597 }
 598
 599 static void tce_iommu_free_table(struct iommu_table *tbl)
 600 {
 601         unsigned long pages = tbl->it_allocated_size >> PAGE_SHIFT;
 602
 603         tce_iommu_userspace_view_free(tbl);
 604         tbl->it_ops->free(tbl);
 605         decrement_locked_vm(pages);
 606 }
 607
 608 static long tce_iommu_create_window(struct tce_container *container,
 609                 __u32 page_shift, __u64 window_size, __u32 levels,
 610                 __u64 *start_addr)
 611 {
 612         struct tce_iommu_group *tcegrp;
 613         struct iommu_table_group *table_group;
 614         struct iommu_table *tbl = NULL;
 615         long ret, num;
 616
 617         num = tce_iommu_find_free_table(container);
 618         if (num < 0)
 619                 return num;
 620
 621         /* Get the first group for ops::create_table */
 622         tcegrp = list_first_entry(&container->group_list,
 623                         struct tce_iommu_group, next);
 624         table_group = iommu_group_get_iommudata(tcegrp->grp);
 625         if (!table_group)
 626                 return -EFAULT;
 627
 628         if (!(table_group->pgsizes & (1ULL << page_shift)))
 629                 return -EINVAL;
 630
 631         if (!table_group->ops->set_window || !table_group->ops->unset_window ||
 632                         !table_group->ops->get_table_size ||
 633                         !table_group->ops->create_table)
 634                 return -EPERM;
 635
 636         /* Create TCE table */
 637         ret = tce_iommu_create_table(container, table_group, num,
 638                         page_shift, window_size, levels, &tbl);
 639         if (ret)
 640                 return ret;
 641
 642         BUG_ON(!tbl->it_ops->free);
 643
 644         /*
 645          * Program the table to every group.
 646          * Groups have been tested for compatibility at the attach time.
 647          */
 648         list_for_each_entry(tcegrp, &container->group_list, next) {
 649                 table_group = iommu_group_get_iommudata(tcegrp->grp);
 650
 651                 ret = table_group->ops->set_window(table_group, num, tbl);
 652                 if (ret)
 653                         goto unset_exit;
 654         }
 655
 656         container->tables[num] = tbl;
 657
 658         /* Return start address assigned by platform in create_table() */
 659         *start_addr = tbl->it_offset << tbl->it_page_shift;
 660
 661         return 0;
 662
 663 unset_exit:
 664         list_for_each_entry(tcegrp, &container->group_list, next) {
 665                 table_group = iommu_group_get_iommudata(tcegrp->grp);
 666                 table_group->ops->unset_window(table_group, num);
 667         }
 668         tce_iommu_free_table(tbl);
 669
 670         return ret;
 671 }
 672
 673 static long tce_iommu_remove_window(struct tce_container *container,
 674                 __u64 start_addr)
 675 {
 676         struct iommu_table_group *table_group = NULL;
 677         struct iommu_table *tbl;
 678         struct tce_iommu_group *tcegrp;
 679         int num;
 680
 681         num = tce_iommu_find_table(container, start_addr, &tbl);
 682         if (num < 0)
 683                 return -EINVAL;
 684
 685         BUG_ON(!tbl->it_size);
 686
 687         /* Detach groups from IOMMUs */
 688         list_for_each_entry(tcegrp, &container->group_list, next) {
 689                 table_group = iommu_group_get_iommudata(tcegrp->grp);
 690
 691                 /*
 692                  * SPAPR TCE IOMMU exposes the default DMA window to
 693                  * the guest via dma32_window_start/size of
 694                  * VFIO_IOMMU_SPAPR_TCE_GET_INFO. Some platforms allow
 695                  * the userspace to remove this window, some do not so
 696                  * here we check for the platform capability.
 697                  */
 698                 if (!table_group->ops || !table_group->ops->unset_window)
 699                         return -EPERM;
 700
 701                 table_group->ops->unset_window(table_group, num);
 702         }
 703
 704         /* Free table */
 705         tce_iommu_clear(container, tbl, tbl->it_offset, tbl->it_size);
 706         tce_iommu_free_table(tbl);
 707         container->tables[num] = NULL;
 708
 709         return 0;
 710 }
 711
 712 static long tce_iommu_ioctl(void *iommu_data,
 713                                  unsigned int cmd, unsigned long arg)
 714 {
 715         struct tce_container *container = iommu_data;
 716         unsigned long minsz, ddwsz;
 717         long ret;
 718
 719         switch (cmd) {
 720         case VFIO_CHECK_EXTENSION:
 721                 switch (arg) {
 722                 case VFIO_SPAPR_TCE_IOMMU:
 723                 case VFIO_SPAPR_TCE_v2_IOMMU:
 724                         ret = 1;
 725                         break;
 726                 default:
 727                         ret = vfio_spapr_iommu_eeh_ioctl(NULL, cmd, arg);
 728                         break;
 729                 }
 730
 731                 return (ret < 0) ? 0 : ret;
 732
 733         case VFIO_IOMMU_SPAPR_TCE_GET_INFO: {
 734                 struct vfio_iommu_spapr_tce_info info;
 735                 struct tce_iommu_group *tcegrp;
 736                 struct iommu_table_group *table_group;
 737
 738                 if (!tce_groups_attached(container))
 739                         return -ENXIO;
 740
 741                 tcegrp = list_first_entry(&container->group_list,
 742                                 struct tce_iommu_group, next);
 743                 table_group = iommu_group_get_iommudata(tcegrp->grp);
 744
 745                 if (!table_group)
 746                         return -ENXIO;
 747
 748                 minsz = offsetofend(struct vfio_iommu_spapr_tce_info,
 749                                 dma32_window_size);
 750
 751                 if (copy_from_user(&info, (void __user *)arg, minsz))
 752                         return -EFAULT;
 753
 754                 if (info.argsz < minsz)
 755                         return -EINVAL;
 756
 757                 info.dma32_window_start = table_group->tce32_start;
 758                 info.dma32_window_size = table_group->tce32_size;
 759                 info.flags = 0;
 760                 memset(&info.ddw, 0, sizeof(info.ddw));
 761
 762                 if (table_group->max_dynamic_windows_supported &&
 763                                 container->v2) {
 764                         info.flags |= VFIO_IOMMU_SPAPR_INFO_DDW;
 765                         info.ddw.pgsizes = table_group->pgsizes;
 766                         info.ddw.max_dynamic_windows_supported =
 767                                 table_group->max_dynamic_windows_supported;
 768                         info.ddw.levels = table_group->max_levels;
 769                 }
 770
 771                 ddwsz = offsetofend(struct vfio_iommu_spapr_tce_info, ddw);
 772
 773                 if (info.argsz >= ddwsz)
 774                         minsz = ddwsz;
 775
 776                 if (copy_to_user((void __user *)arg, &info, minsz))
 777                         return -EFAULT;
 778
 779                 return 0;
 780         }
 781         case VFIO_IOMMU_MAP_DMA: {
 782                 struct vfio_iommu_type1_dma_map param;
 783                 struct iommu_table *tbl = NULL;
 784                 long num;
 785                 enum dma_data_direction direction;
 786
 787                 if (!container->enabled)
 788                         return -EPERM;
 789
 790                 minsz = offsetofend(struct vfio_iommu_type1_dma_map, size);
 791
 792                 if (copy_from_user(&param, (void __user *)arg, minsz))
 793                         return -EFAULT;
 794
 795                 if (param.argsz < minsz)
 796                         return -EINVAL;
 797
 798                 if (param.flags & ~(VFIO_DMA_MAP_FLAG_READ |
 799                                 VFIO_DMA_MAP_FLAG_WRITE))
 800                         return -EINVAL;
 801
 802                 num = tce_iommu_find_table(container, param.iova, &tbl);
 803                 if (num < 0)
 804                         return -ENXIO;
 805
 806                 if ((param.size & ~IOMMU_PAGE_MASK(tbl)) ||
 807                                 (param.vaddr & ~IOMMU_PAGE_MASK(tbl)))
 808                         return -EINVAL;
 809
 810                 /* iova is checked by the IOMMU API */
 811                 if (param.flags & VFIO_DMA_MAP_FLAG_READ) {
 812                         if (param.flags & VFIO_DMA_MAP_FLAG_WRITE)
 813                                 direction = DMA_BIDIRECTIONAL;
 814                         else
 815                                 direction = DMA_TO_DEVICE;
 816                 } else {
 817                         if (param.flags & VFIO_DMA_MAP_FLAG_WRITE)
 818                                 direction = DMA_FROM_DEVICE;
 819                         else
 820                                 return -EINVAL;
 821                 }
 822
 823                 ret = iommu_tce_put_param_check(tbl, param.iova, param.vaddr);
 824                 if (ret)
 825                         return ret;
 826
 827                 if (container->v2)
 828                         ret = tce_iommu_build_v2(container, tbl,
 829                                         param.iova >> tbl->it_page_shift,
 830                                         param.vaddr,
 831                                         param.size >> tbl->it_page_shift,
 832                                         direction);
 833                 else
 834                         ret = tce_iommu_build(container, tbl,
 835                                         param.iova >> tbl->it_page_shift,
 836                                         param.vaddr,
 837                                         param.size >> tbl->it_page_shift,
 838                                         direction);
 839
 840                 iommu_flush_tce(tbl);
 841
 842                 return ret;
 843         }
 844         case VFIO_IOMMU_UNMAP_DMA: {
 845                 struct vfio_iommu_type1_dma_unmap param;
 846                 struct iommu_table *tbl = NULL;
 847                 long num;
 848
 849                 if (!container->enabled)
 850                         return -EPERM;
 851
 852                 minsz = offsetofend(struct vfio_iommu_type1_dma_unmap,
 853                                 size);
 854
 855                 if (copy_from_user(&param, (void __user *)arg, minsz))
 856                         return -EFAULT;
 857
 858                 if (param.argsz < minsz)
 859                         return -EINVAL;
 860
 861                 /* No flag is supported now */
 862                 if (param.flags)
 863                         return -EINVAL;
 864
 865                 num = tce_iommu_find_table(container, param.iova, &tbl);
 866                 if (num < 0)
 867                         return -ENXIO;
 868
 869                 if (param.size & ~IOMMU_PAGE_MASK(tbl))
 870                         return -EINVAL;
 871
 872                 ret = iommu_tce_clear_param_check(tbl, param.iova, 0,
 873                                 param.size >> tbl->it_page_shift);
 874                 if (ret)
 875                         return ret;
 876
 877                 ret = tce_iommu_clear(container, tbl,
 878                                 param.iova >> tbl->it_page_shift,
 879                                 param.size >> tbl->it_page_shift);
 880                 iommu_flush_tce(tbl);
 881
 882                 return ret;
 883         }
 884         case VFIO_IOMMU_SPAPR_REGISTER_MEMORY: {
 885                 struct vfio_iommu_spapr_register_memory param;
 886
 887                 if (!container->v2)
 888                         break;
 889
 890                 minsz = offsetofend(struct vfio_iommu_spapr_register_memory,
 891                                 size);
 892
 893                 if (copy_from_user(&param, (void __user *)arg, minsz))
 894                         return -EFAULT;
 895
 896                 if (param.argsz < minsz)
 897                         return -EINVAL;
 898
 899                 /* No flag is supported now */
 900                 if (param.flags)
 901                         return -EINVAL;
 902
 903                 mutex_lock(&container->lock);
 904                 ret = tce_iommu_register_pages(container, param.vaddr,
 905                                 param.size);
 906                 mutex_unlock(&container->lock);
 907
 908                 return ret;
 909         }
 910         case VFIO_IOMMU_SPAPR_UNREGISTER_MEMORY: {
 911                 struct vfio_iommu_spapr_register_memory param;
 912
 913                 if (!container->v2)
 914                         break;
 915
 916                 minsz = offsetofend(struct vfio_iommu_spapr_register_memory,
 917                                 size);
 918
 919                 if (copy_from_user(&param, (void __user *)arg, minsz))
 920                         return -EFAULT;
 921
 922                 if (param.argsz < minsz)
 923                         return -EINVAL;
 924
 925                 /* No flag is supported now */
 926                 if (param.flags)
 927                         return -EINVAL;
 928
 929                 mutex_lock(&container->lock);
 930                 ret = tce_iommu_unregister_pages(container, param.vaddr,
 931                                 param.size);
 932                 mutex_unlock(&container->lock);
 933
 934                 return ret;
 935         }
 936         case VFIO_IOMMU_ENABLE:
 937                 if (container->v2)
 938                         break;
 939
 940                 mutex_lock(&container->lock);
 941                 ret = tce_iommu_enable(container);
 942                 mutex_unlock(&container->lock);
 943                 return ret;
 944
 945
 946         case VFIO_IOMMU_DISABLE:
 947                 if (container->v2)
 948                         break;
 949
 950                 mutex_lock(&container->lock);
 951                 tce_iommu_disable(container);
 952                 mutex_unlock(&container->lock);
 953                 return 0;
 954
 955         case VFIO_EEH_PE_OP: {
 956                 struct tce_iommu_group *tcegrp;
 957
 958                 ret = 0;
 959                 list_for_each_entry(tcegrp, &container->group_list, next) {
 960                         ret = vfio_spapr_iommu_eeh_ioctl(tcegrp->grp,
 961                                         cmd, arg);
 962                         if (ret)
 963                                 return ret;
 964                 }
 965                 return ret;
 966         }
 967
 968         case VFIO_IOMMU_SPAPR_TCE_CREATE: {
 969                 struct vfio_iommu_spapr_tce_create create;
 970
 971                 if (!container->v2)
 972                         break;
 973
 974                 if (!tce_groups_attached(container))
 975                         return -ENXIO;
 976
 977                 minsz = offsetofend(struct vfio_iommu_spapr_tce_create,
 978                                 start_addr);
 979
 980                 if (copy_from_user(&create, (void __user *)arg, minsz))
 981                         return -EFAULT;
 982
 983                 if (create.argsz < minsz)
 984                         return -EINVAL;
 985
 986                 if (create.flags)
 987                         return -EINVAL;
 988
 989                 mutex_lock(&container->lock);
 990
 991                 ret = tce_iommu_create_window(container, create.page_shift,
 992                                 create.window_size, create.levels,
 993                                 &create.start_addr);
 994
 995                 mutex_unlock(&container->lock);
 996
 997                 if (!ret && copy_to_user((void __user *)arg, &create, minsz))
 998                         ret = -EFAULT;
 999
1000                 return ret;
1001         }
1002         case VFIO_IOMMU_SPAPR_TCE_REMOVE: {
1003                 struct vfio_iommu_spapr_tce_remove remove;
1004
1005                 if (!container->v2)
1006                         break;
1007
1008                 if (!tce_groups_attached(container))
1009                         return -ENXIO;
1010
1011                 minsz = offsetofend(struct vfio_iommu_spapr_tce_remove,
1012                                 start_addr);
1013
1014                 if (copy_from_user(&remove, (void __user *)arg, minsz))
1015                         return -EFAULT;
1016
1017                 if (remove.argsz < minsz)
1018                         return -EINVAL;
1019
1020                 if (remove.flags)
1021                         return -EINVAL;
1022
1023                 mutex_lock(&container->lock);
1024
1025                 ret = tce_iommu_remove_window(container, remove.start_addr);
1026
1027                 mutex_unlock(&container->lock);
1028
1029                 return ret;
1030         }
1031         }
1032
1033         return -ENOTTY;
1034 }
1035
1036 static void tce_iommu_release_ownership(struct tce_container *container,
1037                 struct iommu_table_group *table_group)
1038 {
1039         int i;
1040
1041         for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
1042                 struct iommu_table *tbl = container->tables[i];
1043
1044                 if (!tbl)
1045                         continue;
1046
1047                 tce_iommu_clear(container, tbl, tbl->it_offset, tbl->it_size);
1048                 tce_iommu_userspace_view_free(tbl);
1049                 if (tbl->it_map)
1050                         iommu_release_ownership(tbl);
1051
1052                 container->tables[i] = NULL;
1053         }
1054 }
1055
1056 static int tce_iommu_take_ownership(struct tce_container *container,
1057                 struct iommu_table_group *table_group)
1058 {
1059         int i, j, rc = 0;
1060
1061         for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
1062                 struct iommu_table *tbl = table_group->tables[i];
1063
1064                 if (!tbl || !tbl->it_map)
1065                         continue;
1066
1067                 rc = tce_iommu_userspace_view_alloc(tbl);
1068                 if (!rc)
1069                         rc = iommu_take_ownership(tbl);
1070
1071                 if (rc) {
1072                         for (j = 0; j < i; ++j)
1073                                 iommu_release_ownership(
1074                                                 table_group->tables[j]);
1075
1076                         return rc;
1077                 }
1078         }
1079
1080         for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i)
1081                 container->tables[i] = table_group->tables[i];
1082
1083         return 0;
1084 }
1085
1086 static void tce_iommu_release_ownership_ddw(struct tce_container *container,
1087                 struct iommu_table_group *table_group)
1088 {
1089         long i;
1090
1091         if (!table_group->ops->unset_window) {
1092                 WARN_ON_ONCE(1);
1093                 return;
1094         }
1095
1096         for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i)
1097                 table_group->ops->unset_window(table_group, i);
1098
1099         table_group->ops->release_ownership(table_group);
1100 }
1101
1102 static long tce_iommu_take_ownership_ddw(struct tce_container *container,
1103                 struct iommu_table_group *table_group)
1104 {
1105         long i, ret = 0;
1106         struct iommu_table *tbl = NULL;
1107
1108         if (!table_group->ops->create_table || !table_group->ops->set_window ||
1109                         !table_group->ops->release_ownership) {
1110                 WARN_ON_ONCE(1);
1111                 return -EFAULT;
1112         }
1113
1114         table_group->ops->take_ownership(table_group);
1115
1116         /*
1117          * If it the first group attached, check if there is
1118          * a default DMA window and create one if none as
1119          * the userspace expects it to exist.
1120          */
1121         if (!tce_groups_attached(container) && !container->tables[0]) {
1122                 ret = tce_iommu_create_table(container,
1123                                 table_group,
1124                                 0, /* window number */
1125                                 IOMMU_PAGE_SHIFT_4K,
1126                                 table_group->tce32_size,
1127                                 1, /* default levels */
1128                                 &tbl);
1129                 if (ret)
1130                         goto release_exit;
1131                 else
1132                         container->tables[0] = tbl;
1133         }
1134
1135         /* Set all windows to the new group */
1136         for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) {
1137                 tbl = container->tables[i];
1138
1139                 if (!tbl)
1140                         continue;
1141
1142                 /* Set the default window to a new group */
1143                 ret = table_group->ops->set_window(table_group, i, tbl);
1144                 if (ret)
1145                         goto release_exit;
1146         }
1147
1148         return 0;
1149
1150 release_exit:
1151         for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i)
1152                 table_group->ops->unset_window(table_group, i);
1153
1154         table_group->ops->release_ownership(table_group);
1155
1156         return ret;
1157 }
1158
1159 static int tce_iommu_attach_group(void *iommu_data,
1160                 struct iommu_group *iommu_group)
1161 {
1162         int ret;
1163         struct tce_container *container = iommu_data;
1164         struct iommu_table_group *table_group;
1165         struct tce_iommu_group *tcegrp = NULL;
1166
1167         mutex_lock(&container->lock);
1168
1169         /* pr_debug("tce_vfio: Attaching group #%u to iommu %p\n",
1170                         iommu_group_id(iommu_group), iommu_group); */
1171         table_group = iommu_group_get_iommudata(iommu_group);
1172
1173         if (tce_groups_attached(container) && (!table_group->ops ||
1174                         !table_group->ops->take_ownership ||
1175                         !table_group->ops->release_ownership)) {
1176                 ret = -EBUSY;
1177                 goto unlock_exit;
1178         }
1179
1180         /* Check if new group has the same iommu_ops (i.e. compatible) */
1181         list_for_each_entry(tcegrp, &container->group_list, next) {
1182                 struct iommu_table_group *table_group_tmp;
1183
1184                 if (tcegrp->grp == iommu_group) {
1185                         pr_warn("tce_vfio: Group %d is already attached\n",
1186                                         iommu_group_id(iommu_group));
1187                         ret = -EBUSY;
1188                         goto unlock_exit;
1189                 }
1190                 table_group_tmp = iommu_group_get_iommudata(tcegrp->grp);
1191                 if (table_group_tmp->ops != table_group->ops) {
1192                         pr_warn("tce_vfio: Group %d is incompatible with group %d\n",
1193                                         iommu_group_id(iommu_group),
1194                                         iommu_group_id(tcegrp->grp));
1195                         ret = -EPERM;
1196                         goto unlock_exit;
1197                 }
1198         }
1199
1200         tcegrp = kzalloc(sizeof(*tcegrp), GFP_KERNEL);
1201         if (!tcegrp) {
1202                 ret = -ENOMEM;
1203                 goto unlock_exit;
1204         }
1205
1206         if (!table_group->ops || !table_group->ops->take_ownership ||
1207                         !table_group->ops->release_ownership)
1208                 ret = tce_iommu_take_ownership(container, table_group);
1209         else
1210                 ret = tce_iommu_take_ownership_ddw(container, table_group);
1211
1212         if (!ret) {
1213                 tcegrp->grp = iommu_group;
1214                 list_add(&tcegrp->next, &container->group_list);
1215         }
1216
1217 unlock_exit:
1218         if (ret && tcegrp)
1219                 kfree(tcegrp);
1220
1221         mutex_unlock(&container->lock);
1222
1223         return ret;
1224 }
1225
1226 static void tce_iommu_detach_group(void *iommu_data,
1227                 struct iommu_group *iommu_group)
1228 {
1229         struct tce_container *container = iommu_data;
1230         struct iommu_table_group *table_group;
1231         bool found = false;
1232         struct tce_iommu_group *tcegrp;
1233
1234         mutex_lock(&container->lock);
1235
1236         list_for_each_entry(tcegrp, &container->group_list, next) {
1237                 if (tcegrp->grp == iommu_group) {
1238                         found = true;
1239                         break;
1240                 }
1241         }
1242
1243         if (!found) {
1244                 pr_warn("tce_vfio: detaching unattached group #%u\n",
1245                                 iommu_group_id(iommu_group));
1246                 goto unlock_exit;
1247         }
1248
1249         list_del(&tcegrp->next);
1250         kfree(tcegrp);
1251
1252         table_group = iommu_group_get_iommudata(iommu_group);
1253         BUG_ON(!table_group);
1254
1255         if (!table_group->ops || !table_group->ops->release_ownership)
1256                 tce_iommu_release_ownership(container, table_group);
1257         else
1258                 tce_iommu_release_ownership_ddw(container, table_group);
1259
1260 unlock_exit:
1261         mutex_unlock(&container->lock);
1262 }
1263
1264 const struct vfio_iommu_driver_ops tce_iommu_driver_ops = {
1265         .name           = "iommu-vfio-powerpc",
1266         .owner          = THIS_MODULE,
1267         .open           = tce_iommu_open,
1268         .release        = tce_iommu_release,
1269         .ioctl          = tce_iommu_ioctl,
1270         .attach_group   = tce_iommu_attach_group,
1271         .detach_group   = tce_iommu_detach_group,
1272 };
1273
1274 static int __init tce_iommu_init(void)
1275 {
1276         return vfio_register_iommu_driver(&tce_iommu_driver_ops);
1277 }
1278
1279 static void __exit tce_iommu_cleanup(void)
1280 {
1281         vfio_unregister_iommu_driver(&tce_iommu_driver_ops);
1282 }
1283
1284 module_init(tce_iommu_init);
1285 module_exit(tce_iommu_cleanup);
1286
1287 MODULE_VERSION(DRIVER_VERSION);
1288 MODULE_LICENSE("GPL v2");
1289 MODULE_AUTHOR(DRIVER_AUTHOR);
1290 MODULE_DESCRIPTION(DRIVER_DESC);
1291