drivers/gpu/drm/i915/gem/i915_gem_ttm.c

   1 // SPDX-License-Identifier: MIT
   2 /*
   3  * Copyright © 2021 Intel Corporation
   4  */
   5
   6 #include <drm/ttm/ttm_bo_driver.h>
   7 #include <drm/ttm/ttm_placement.h>
   8
   9 #include "i915_drv.h"
  10 #include "intel_memory_region.h"
  11 #include "intel_region_ttm.h"
  12
  13 #include "gem/i915_gem_mman.h"
  14 #include "gem/i915_gem_object.h"
  15 #include "gem/i915_gem_region.h"
  16 #include "gem/i915_gem_ttm.h"
  17 #include "gem/i915_gem_ttm_move.h"
  18 #include "gem/i915_gem_ttm_pm.h"
  19
  20 #define I915_TTM_PRIO_PURGE     0
  21 #define I915_TTM_PRIO_NO_PAGES  1
  22 #define I915_TTM_PRIO_HAS_PAGES 2
  23
  24 /*
  25  * Size of struct ttm_place vector in on-stack struct ttm_placement allocs
  26  */
  27 #define I915_TTM_MAX_PLACEMENTS INTEL_REGION_UNKNOWN
  28
  29 /**
  30  * struct i915_ttm_tt - TTM page vector with additional private information
  31  * @ttm: The base TTM page vector.
  32  * @dev: The struct device used for dma mapping and unmapping.
  33  * @cached_rsgt: The cached scatter-gather table.
  34  * @is_shmem: Set if using shmem.
  35  * @filp: The shmem file, if using shmem backend.
  36  *
  37  * Note that DMA may be going on right up to the point where the page-
  38  * vector is unpopulated in delayed destroy. Hence keep the
  39  * scatter-gather table mapped and cached up to that point. This is
  40  * different from the cached gem object io scatter-gather table which
  41  * doesn't have an associated dma mapping.
  42  */
  43 struct i915_ttm_tt {
  44         struct ttm_tt ttm;
  45         struct device *dev;
  46         struct i915_refct_sgt cached_rsgt;
  47
  48         bool is_shmem;
  49         struct file *filp;
  50 };
  51
  52 static const struct ttm_place sys_placement_flags = {
  53         .fpfn = 0,
  54         .lpfn = 0,
  55         .mem_type = I915_PL_SYSTEM,
  56         .flags = 0,
  57 };
  58
  59 static struct ttm_placement i915_sys_placement = {
  60         .num_placement = 1,
  61         .placement = &sys_placement_flags,
  62         .num_busy_placement = 1,
  63         .busy_placement = &sys_placement_flags,
  64 };
  65
  66 /**
  67  * i915_ttm_sys_placement - Return the struct ttm_placement to be
  68  * used for an object in system memory.
  69  *
  70  * Rather than making the struct extern, use this
  71  * function.
  72  *
  73  * Return: A pointer to a static variable for sys placement.
  74  */
  75 struct ttm_placement *i915_ttm_sys_placement(void)
  76 {
  77         return &i915_sys_placement;
  78 }
  79
  80 static int i915_ttm_err_to_gem(int err)
  81 {
  82         /* Fastpath */
  83         if (likely(!err))
  84                 return 0;
  85
  86         switch (err) {
  87         case -EBUSY:
  88                 /*
  89                  * TTM likes to convert -EDEADLK to -EBUSY, and wants us to
  90                  * restart the operation, since we don't record the contending
  91                  * lock. We use -EAGAIN to restart.
  92                  */
  93                 return -EAGAIN;
  94         case -ENOSPC:
  95                 /*
  96                  * Memory type / region is full, and we can't evict.
  97                  * Except possibly system, that returns -ENOMEM;
  98                  */
  99                 return -ENXIO;
 100         default:
 101                 break;
 102         }
 103
 104         return err;
 105 }
 106
 107 static enum ttm_caching
 108 i915_ttm_select_tt_caching(const struct drm_i915_gem_object *obj)
 109 {
 110         /*
 111          * Objects only allowed in system get cached cpu-mappings, or when
 112          * evicting lmem-only buffers to system for swapping. Other objects get
 113          * WC mapping for now. Even if in system.
 114          */
 115         if (obj->mm.n_placements <= 1)
 116                 return ttm_cached;
 117
 118         return ttm_write_combined;
 119 }
 120
 121 static void
 122 i915_ttm_place_from_region(const struct intel_memory_region *mr,
 123                            struct ttm_place *place,
 124                            unsigned int flags)
 125 {
 126         memset(place, 0, sizeof(*place));
 127         place->mem_type = intel_region_to_ttm_type(mr);
 128
 129         if (flags & I915_BO_ALLOC_CONTIGUOUS)
 130                 place->flags = TTM_PL_FLAG_CONTIGUOUS;
 131 }
 132
 133 static void
 134 i915_ttm_placement_from_obj(const struct drm_i915_gem_object *obj,
 135                             struct ttm_place *requested,
 136                             struct ttm_place *busy,
 137                             struct ttm_placement *placement)
 138 {
 139         unsigned int num_allowed = obj->mm.n_placements;
 140         unsigned int flags = obj->flags;
 141         unsigned int i;
 142
 143         placement->num_placement = 1;
 144         i915_ttm_place_from_region(num_allowed ? obj->mm.placements[0] :
 145                                    obj->mm.region, requested, flags);
 146
 147         /* Cache this on object? */
 148         placement->num_busy_placement = num_allowed;
 149         for (i = 0; i < placement->num_busy_placement; ++i)
 150                 i915_ttm_place_from_region(obj->mm.placements[i], busy + i, flags);
 151
 152         if (num_allowed == 0) {
 153                 *busy = *requested;
 154                 placement->num_busy_placement = 1;
 155         }
 156
 157         placement->placement = requested;
 158         placement->busy_placement = busy;
 159 }
 160
 161 static int i915_ttm_tt_shmem_populate(struct ttm_device *bdev,
 162                                       struct ttm_tt *ttm,
 163                                       struct ttm_operation_ctx *ctx)
 164 {
 165         struct drm_i915_private *i915 = container_of(bdev, typeof(*i915), bdev);
 166         struct intel_memory_region *mr = i915->mm.regions[INTEL_MEMORY_SYSTEM];
 167         struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
 168         const unsigned int max_segment = i915_sg_segment_size();
 169         const size_t size = (size_t)ttm->num_pages << PAGE_SHIFT;
 170         struct file *filp = i915_tt->filp;
 171         struct sgt_iter sgt_iter;
 172         struct sg_table *st;
 173         struct page *page;
 174         unsigned long i;
 175         int err;
 176
 177         if (!filp) {
 178                 struct address_space *mapping;
 179                 gfp_t mask;
 180
 181                 filp = shmem_file_setup("i915-shmem-tt", size, VM_NORESERVE);
 182                 if (IS_ERR(filp))
 183                         return PTR_ERR(filp);
 184
 185                 mask = GFP_HIGHUSER | __GFP_RECLAIMABLE;
 186
 187                 mapping = filp->f_mapping;
 188                 mapping_set_gfp_mask(mapping, mask);
 189                 GEM_BUG_ON(!(mapping_gfp_mask(mapping) & __GFP_RECLAIM));
 190
 191                 i915_tt->filp = filp;
 192         }
 193
 194         st = &i915_tt->cached_rsgt.table;
 195         err = shmem_sg_alloc_table(i915, st, size, mr, filp->f_mapping,
 196                                    max_segment);
 197         if (err)
 198                 return err;
 199
 200         err = dma_map_sgtable(i915_tt->dev, st, DMA_BIDIRECTIONAL,
 201                               DMA_ATTR_SKIP_CPU_SYNC);
 202         if (err)
 203                 goto err_free_st;
 204
 205         i = 0;
 206         for_each_sgt_page(page, sgt_iter, st)
 207                 ttm->pages[i++] = page;
 208
 209         if (ttm->page_flags & TTM_TT_FLAG_SWAPPED)
 210                 ttm->page_flags &= ~TTM_TT_FLAG_SWAPPED;
 211
 212         return 0;
 213
 214 err_free_st:
 215         shmem_sg_free_table(st, filp->f_mapping, false, false);
 216
 217         return err;
 218 }
 219
 220 static void i915_ttm_tt_shmem_unpopulate(struct ttm_tt *ttm)
 221 {
 222         struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
 223         bool backup = ttm->page_flags & TTM_TT_FLAG_SWAPPED;
 224         struct sg_table *st = &i915_tt->cached_rsgt.table;
 225
 226         shmem_sg_free_table(st, file_inode(i915_tt->filp)->i_mapping,
 227                             backup, backup);
 228 }
 229
 230 static void i915_ttm_tt_release(struct kref *ref)
 231 {
 232         struct i915_ttm_tt *i915_tt =
 233                 container_of(ref, typeof(*i915_tt), cached_rsgt.kref);
 234         struct sg_table *st = &i915_tt->cached_rsgt.table;
 235
 236         GEM_WARN_ON(st->sgl);
 237
 238         kfree(i915_tt);
 239 }
 240
 241 static const struct i915_refct_sgt_ops tt_rsgt_ops = {
 242         .release = i915_ttm_tt_release
 243 };
 244
 245 static struct ttm_tt *i915_ttm_tt_create(struct ttm_buffer_object *bo,
 246                                          uint32_t page_flags)
 247 {
 248         struct ttm_resource_manager *man =
 249                 ttm_manager_type(bo->bdev, bo->resource->mem_type);
 250         struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
 251         enum ttm_caching caching;
 252         struct i915_ttm_tt *i915_tt;
 253         int ret;
 254
 255         if (!obj)
 256                 return NULL;
 257
 258         i915_tt = kzalloc(sizeof(*i915_tt), GFP_KERNEL);
 259         if (!i915_tt)
 260                 return NULL;
 261
 262         if (obj->flags & I915_BO_ALLOC_CPU_CLEAR &&
 263             man->use_tt)
 264                 page_flags |= TTM_TT_FLAG_ZERO_ALLOC;
 265
 266         caching = i915_ttm_select_tt_caching(obj);
 267         if (i915_gem_object_is_shrinkable(obj) && caching == ttm_cached) {
 268                 page_flags |= TTM_TT_FLAG_EXTERNAL |
 269                               TTM_TT_FLAG_EXTERNAL_MAPPABLE;
 270                 i915_tt->is_shmem = true;
 271         }
 272
 273         ret = ttm_tt_init(&i915_tt->ttm, bo, page_flags, caching);
 274         if (ret)
 275                 goto err_free;
 276
 277         __i915_refct_sgt_init(&i915_tt->cached_rsgt, bo->base.size,
 278                               &tt_rsgt_ops);
 279
 280         i915_tt->dev = obj->base.dev->dev;
 281
 282         return &i915_tt->ttm;
 283
 284 err_free:
 285         kfree(i915_tt);
 286         return NULL;
 287 }
 288
 289 static int i915_ttm_tt_populate(struct ttm_device *bdev,
 290                                 struct ttm_tt *ttm,
 291                                 struct ttm_operation_ctx *ctx)
 292 {
 293         struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
 294
 295         if (i915_tt->is_shmem)
 296                 return i915_ttm_tt_shmem_populate(bdev, ttm, ctx);
 297
 298         return ttm_pool_alloc(&bdev->pool, ttm, ctx);
 299 }
 300
 301 static void i915_ttm_tt_unpopulate(struct ttm_device *bdev, struct ttm_tt *ttm)
 302 {
 303         struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
 304         struct sg_table *st = &i915_tt->cached_rsgt.table;
 305
 306         if (st->sgl)
 307                 dma_unmap_sgtable(i915_tt->dev, st, DMA_BIDIRECTIONAL, 0);
 308
 309         if (i915_tt->is_shmem) {
 310                 i915_ttm_tt_shmem_unpopulate(ttm);
 311         } else {
 312                 sg_free_table(st);
 313                 ttm_pool_free(&bdev->pool, ttm);
 314         }
 315 }
 316
 317 static void i915_ttm_tt_destroy(struct ttm_device *bdev, struct ttm_tt *ttm)
 318 {
 319         struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
 320
 321         if (i915_tt->filp)
 322                 fput(i915_tt->filp);
 323
 324         ttm_tt_fini(ttm);
 325         i915_refct_sgt_put(&i915_tt->cached_rsgt);
 326 }
 327
 328 static bool i915_ttm_eviction_valuable(struct ttm_buffer_object *bo,
 329                                        const struct ttm_place *place)
 330 {
 331         struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
 332
 333         if (!obj)
 334                 return false;
 335
 336         /*
 337          * EXTERNAL objects should never be swapped out by TTM, instead we need
 338          * to handle that ourselves. TTM will already skip such objects for us,
 339          * but we would like to avoid grabbing locks for no good reason.
 340          */
 341         if (bo->ttm && bo->ttm->page_flags & TTM_TT_FLAG_EXTERNAL)
 342                 return false;
 343
 344         /* Will do for now. Our pinned objects are still on TTM's LRU lists */
 345         return i915_gem_object_evictable(obj);
 346 }
 347
 348 static void i915_ttm_evict_flags(struct ttm_buffer_object *bo,
 349                                  struct ttm_placement *placement)
 350 {
 351         *placement = i915_sys_placement;
 352 }
 353
 354 /**
 355  * i915_ttm_free_cached_io_rsgt - Free object cached LMEM information
 356  * @obj: The GEM object
 357  * This function frees any LMEM-related information that is cached on
 358  * the object. For example the radix tree for fast page lookup and the
 359  * cached refcounted sg-table
 360  */
 361 void i915_ttm_free_cached_io_rsgt(struct drm_i915_gem_object *obj)
 362 {
 363         struct radix_tree_iter iter;
 364         void __rcu **slot;
 365
 366         if (!obj->ttm.cached_io_rsgt)
 367                 return;
 368
 369         rcu_read_lock();
 370         radix_tree_for_each_slot(slot, &obj->ttm.get_io_page.radix, &iter, 0)
 371                 radix_tree_delete(&obj->ttm.get_io_page.radix, iter.index);
 372         rcu_read_unlock();
 373
 374         i915_refct_sgt_put(obj->ttm.cached_io_rsgt);
 375         obj->ttm.cached_io_rsgt = NULL;
 376 }
 377
 378 /**
 379  * i915_ttm_purge - Clear an object of its memory
 380  * @obj: The object
 381  *
 382  * This function is called to clear an object of it's memory when it is
 383  * marked as not needed anymore.
 384  *
 385  * Return: 0 on success, negative error code on failure.
 386  */
 387 int i915_ttm_purge(struct drm_i915_gem_object *obj)
 388 {
 389         struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
 390         struct i915_ttm_tt *i915_tt =
 391                 container_of(bo->ttm, typeof(*i915_tt), ttm);
 392         struct ttm_operation_ctx ctx = {
 393                 .interruptible = true,
 394                 .no_wait_gpu = false,
 395         };
 396         struct ttm_placement place = {};
 397         int ret;
 398
 399         if (obj->mm.madv == __I915_MADV_PURGED)
 400                 return 0;
 401
 402         ret = ttm_bo_validate(bo, &place, &ctx);
 403         if (ret)
 404                 return ret;
 405
 406         if (bo->ttm && i915_tt->filp) {
 407                 /*
 408                  * The below fput(which eventually calls shmem_truncate) might
 409                  * be delayed by worker, so when directly called to purge the
 410                  * pages(like by the shrinker) we should try to be more
 411                  * aggressive and release the pages immediately.
 412                  */
 413                 shmem_truncate_range(file_inode(i915_tt->filp),
 414                                      0, (loff_t)-1);
 415                 fput(fetch_and_zero(&i915_tt->filp));
 416         }
 417
 418         obj->write_domain = 0;
 419         obj->read_domains = 0;
 420         i915_ttm_adjust_gem_after_move(obj);
 421         i915_ttm_free_cached_io_rsgt(obj);
 422         obj->mm.madv = __I915_MADV_PURGED;
 423
 424         return 0;
 425 }
 426
 427 static int i915_ttm_shrinker_release_pages(struct drm_i915_gem_object *obj,
 428                                            bool no_wait_gpu,
 429                                            bool should_writeback)
 430 {
 431         struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
 432         struct i915_ttm_tt *i915_tt =
 433                 container_of(bo->ttm, typeof(*i915_tt), ttm);
 434         struct ttm_operation_ctx ctx = {
 435                 .interruptible = true,
 436                 .no_wait_gpu = no_wait_gpu,
 437         };
 438         struct ttm_placement place = {};
 439         int ret;
 440
 441         if (!bo->ttm || bo->resource->mem_type != TTM_PL_SYSTEM)
 442                 return 0;
 443
 444         GEM_BUG_ON(!i915_tt->is_shmem);
 445
 446         if (!i915_tt->filp)
 447                 return 0;
 448
 449         ret = ttm_bo_wait_ctx(bo, &ctx);
 450         if (ret)
 451                 return ret;
 452
 453         switch (obj->mm.madv) {
 454         case I915_MADV_DONTNEED:
 455                 return i915_ttm_purge(obj);
 456         case __I915_MADV_PURGED:
 457                 return 0;
 458         }
 459
 460         if (bo->ttm->page_flags & TTM_TT_FLAG_SWAPPED)
 461                 return 0;
 462
 463         bo->ttm->page_flags |= TTM_TT_FLAG_SWAPPED;
 464         ret = ttm_bo_validate(bo, &place, &ctx);
 465         if (ret) {
 466                 bo->ttm->page_flags &= ~TTM_TT_FLAG_SWAPPED;
 467                 return ret;
 468         }
 469
 470         if (should_writeback)
 471                 __shmem_writeback(obj->base.size, i915_tt->filp->f_mapping);
 472
 473         return 0;
 474 }
 475
 476 static void i915_ttm_delete_mem_notify(struct ttm_buffer_object *bo)
 477 {
 478         struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
 479
 480         if (likely(obj)) {
 481                 __i915_gem_object_pages_fini(obj);
 482                 i915_ttm_free_cached_io_rsgt(obj);
 483         }
 484 }
 485
 486 static struct i915_refct_sgt *i915_ttm_tt_get_st(struct ttm_tt *ttm)
 487 {
 488         struct i915_ttm_tt *i915_tt = container_of(ttm, typeof(*i915_tt), ttm);
 489         struct sg_table *st;
 490         int ret;
 491
 492         if (i915_tt->cached_rsgt.table.sgl)
 493                 return i915_refct_sgt_get(&i915_tt->cached_rsgt);
 494
 495         st = &i915_tt->cached_rsgt.table;
 496         ret = sg_alloc_table_from_pages_segment(st,
 497                         ttm->pages, ttm->num_pages,
 498                         0, (unsigned long)ttm->num_pages << PAGE_SHIFT,
 499                         i915_sg_segment_size(), GFP_KERNEL);
 500         if (ret) {
 501                 st->sgl = NULL;
 502                 return ERR_PTR(ret);
 503         }
 504
 505         ret = dma_map_sgtable(i915_tt->dev, st, DMA_BIDIRECTIONAL, 0);
 506         if (ret) {
 507                 sg_free_table(st);
 508                 return ERR_PTR(ret);
 509         }
 510
 511         return i915_refct_sgt_get(&i915_tt->cached_rsgt);
 512 }
 513
 514 /**
 515  * i915_ttm_resource_get_st - Get a refcounted sg-table pointing to the
 516  * resource memory
 517  * @obj: The GEM object used for sg-table caching
 518  * @res: The struct ttm_resource for which an sg-table is requested.
 519  *
 520  * This function returns a refcounted sg-table representing the memory
 521  * pointed to by @res. If @res is the object's current resource it may also
 522  * cache the sg_table on the object or attempt to access an already cached
 523  * sg-table. The refcounted sg-table needs to be put when no-longer in use.
 524  *
 525  * Return: A valid pointer to a struct i915_refct_sgt or error pointer on
 526  * failure.
 527  */
 528 struct i915_refct_sgt *
 529 i915_ttm_resource_get_st(struct drm_i915_gem_object *obj,
 530                          struct ttm_resource *res)
 531 {
 532         struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
 533
 534         if (!i915_ttm_gtt_binds_lmem(res))
 535                 return i915_ttm_tt_get_st(bo->ttm);
 536
 537         /*
 538          * If CPU mapping differs, we need to add the ttm_tt pages to
 539          * the resulting st. Might make sense for GGTT.
 540          */
 541         GEM_WARN_ON(!i915_ttm_cpu_maps_iomem(res));
 542         if (bo->resource == res) {
 543                 if (!obj->ttm.cached_io_rsgt) {
 544                         struct i915_refct_sgt *rsgt;
 545
 546                         rsgt = intel_region_ttm_resource_to_rsgt(obj->mm.region,
 547                                                                  res);
 548                         if (IS_ERR(rsgt))
 549                                 return rsgt;
 550
 551                         obj->ttm.cached_io_rsgt = rsgt;
 552                 }
 553                 return i915_refct_sgt_get(obj->ttm.cached_io_rsgt);
 554         }
 555
 556         return intel_region_ttm_resource_to_rsgt(obj->mm.region, res);
 557 }
 558
 559 static int i915_ttm_truncate(struct drm_i915_gem_object *obj)
 560 {
 561         struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
 562         int err;
 563
 564         WARN_ON_ONCE(obj->mm.madv == I915_MADV_WILLNEED);
 565
 566         err = i915_ttm_move_notify(bo);
 567         if (err)
 568                 return err;
 569
 570         return i915_ttm_purge(obj);
 571 }
 572
 573 static void i915_ttm_swap_notify(struct ttm_buffer_object *bo)
 574 {
 575         struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
 576         int ret;
 577
 578         if (!obj)
 579                 return;
 580
 581         ret = i915_ttm_move_notify(bo);
 582         GEM_WARN_ON(ret);
 583         GEM_WARN_ON(obj->ttm.cached_io_rsgt);
 584         if (!ret && obj->mm.madv != I915_MADV_WILLNEED)
 585                 i915_ttm_purge(obj);
 586 }
 587
 588 static int i915_ttm_io_mem_reserve(struct ttm_device *bdev, struct ttm_resource *mem)
 589 {
 590         if (!i915_ttm_cpu_maps_iomem(mem))
 591                 return 0;
 592
 593         mem->bus.caching = ttm_write_combined;
 594         mem->bus.is_iomem = true;
 595
 596         return 0;
 597 }
 598
 599 static unsigned long i915_ttm_io_mem_pfn(struct ttm_buffer_object *bo,
 600                                          unsigned long page_offset)
 601 {
 602         struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
 603         struct scatterlist *sg;
 604         unsigned long base;
 605         unsigned int ofs;
 606
 607         GEM_BUG_ON(!obj);
 608         GEM_WARN_ON(bo->ttm);
 609
 610         base = obj->mm.region->iomap.base - obj->mm.region->region.start;
 611         sg = __i915_gem_object_get_sg(obj, &obj->ttm.get_io_page, page_offset, &ofs, true);
 612
 613         return ((base + sg_dma_address(sg)) >> PAGE_SHIFT) + ofs;
 614 }
 615
 616 /*
 617  * All callbacks need to take care not to downcast a struct ttm_buffer_object
 618  * without checking its subclass, since it might be a TTM ghost object.
 619  */
 620 static struct ttm_device_funcs i915_ttm_bo_driver = {
 621         .ttm_tt_create = i915_ttm_tt_create,
 622         .ttm_tt_populate = i915_ttm_tt_populate,
 623         .ttm_tt_unpopulate = i915_ttm_tt_unpopulate,
 624         .ttm_tt_destroy = i915_ttm_tt_destroy,
 625         .eviction_valuable = i915_ttm_eviction_valuable,
 626         .evict_flags = i915_ttm_evict_flags,
 627         .move = i915_ttm_move,
 628         .swap_notify = i915_ttm_swap_notify,
 629         .delete_mem_notify = i915_ttm_delete_mem_notify,
 630         .io_mem_reserve = i915_ttm_io_mem_reserve,
 631         .io_mem_pfn = i915_ttm_io_mem_pfn,
 632 };
 633
 634 /**
 635  * i915_ttm_driver - Return a pointer to the TTM device funcs
 636  *
 637  * Return: Pointer to statically allocated TTM device funcs.
 638  */
 639 struct ttm_device_funcs *i915_ttm_driver(void)
 640 {
 641         return &i915_ttm_bo_driver;
 642 }
 643
 644 static int __i915_ttm_get_pages(struct drm_i915_gem_object *obj,
 645                                 struct ttm_placement *placement)
 646 {
 647         struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
 648         struct ttm_operation_ctx ctx = {
 649                 .interruptible = true,
 650                 .no_wait_gpu = false,
 651         };
 652         int real_num_busy;
 653         int ret;
 654
 655         /* First try only the requested placement. No eviction. */
 656         real_num_busy = fetch_and_zero(&placement->num_busy_placement);
 657         ret = ttm_bo_validate(bo, placement, &ctx);
 658         if (ret) {
 659                 ret = i915_ttm_err_to_gem(ret);
 660                 /*
 661                  * Anything that wants to restart the operation gets to
 662                  * do that.
 663                  */
 664                 if (ret == -EDEADLK || ret == -EINTR || ret == -ERESTARTSYS ||
 665                     ret == -EAGAIN)
 666                         return ret;
 667
 668                 /*
 669                  * If the initial attempt fails, allow all accepted placements,
 670                  * evicting if necessary.
 671                  */
 672                 placement->num_busy_placement = real_num_busy;
 673                 ret = ttm_bo_validate(bo, placement, &ctx);
 674                 if (ret)
 675                         return i915_ttm_err_to_gem(ret);
 676         }
 677
 678         if (bo->ttm && !ttm_tt_is_populated(bo->ttm)) {
 679                 ret = ttm_tt_populate(bo->bdev, bo->ttm, &ctx);
 680                 if (ret)
 681                         return ret;
 682
 683                 i915_ttm_adjust_domains_after_move(obj);
 684                 i915_ttm_adjust_gem_after_move(obj);
 685         }
 686
 687         if (!i915_gem_object_has_pages(obj)) {
 688                 struct i915_refct_sgt *rsgt =
 689                         i915_ttm_resource_get_st(obj, bo->resource);
 690
 691                 if (IS_ERR(rsgt))
 692                         return PTR_ERR(rsgt);
 693
 694                 GEM_BUG_ON(obj->mm.rsgt);
 695                 obj->mm.rsgt = rsgt;
 696                 __i915_gem_object_set_pages(obj, &rsgt->table,
 697                                             i915_sg_dma_sizes(rsgt->table.sgl));
 698         }
 699
 700         i915_ttm_adjust_lru(obj);
 701         return ret;
 702 }
 703
 704 static int i915_ttm_get_pages(struct drm_i915_gem_object *obj)
 705 {
 706         struct ttm_place requested, busy[I915_TTM_MAX_PLACEMENTS];
 707         struct ttm_placement placement;
 708
 709         GEM_BUG_ON(obj->mm.n_placements > I915_TTM_MAX_PLACEMENTS);
 710
 711         /* Move to the requested placement. */
 712         i915_ttm_placement_from_obj(obj, &requested, busy, &placement);
 713
 714         return __i915_ttm_get_pages(obj, &placement);
 715 }
 716
 717 /**
 718  * DOC: Migration vs eviction
 719  *
 720  * GEM migration may not be the same as TTM migration / eviction. If
 721  * the TTM core decides to evict an object it may be evicted to a
 722  * TTM memory type that is not in the object's allowable GEM regions, or
 723  * in fact theoretically to a TTM memory type that doesn't correspond to
 724  * a GEM memory region. In that case the object's GEM region is not
 725  * updated, and the data is migrated back to the GEM region at
 726  * get_pages time. TTM may however set up CPU ptes to the object even
 727  * when it is evicted.
 728  * Gem forced migration using the i915_ttm_migrate() op, is allowed even
 729  * to regions that are not in the object's list of allowable placements.
 730  */
 731 static int i915_ttm_migrate(struct drm_i915_gem_object *obj,
 732                             struct intel_memory_region *mr)
 733 {
 734         struct ttm_place requested;
 735         struct ttm_placement placement;
 736         int ret;
 737
 738         i915_ttm_place_from_region(mr, &requested, obj->flags);
 739         placement.num_placement = 1;
 740         placement.num_busy_placement = 1;
 741         placement.placement = &requested;
 742         placement.busy_placement = &requested;
 743
 744         ret = __i915_ttm_get_pages(obj, &placement);
 745         if (ret)
 746                 return ret;
 747
 748         /*
 749          * Reinitialize the region bindings. This is primarily
 750          * required for objects where the new region is not in
 751          * its allowable placements.
 752          */
 753         if (obj->mm.region != mr) {
 754                 i915_gem_object_release_memory_region(obj);
 755                 i915_gem_object_init_memory_region(obj, mr);
 756         }
 757
 758         return 0;
 759 }
 760
 761 static void i915_ttm_put_pages(struct drm_i915_gem_object *obj,
 762                                struct sg_table *st)
 763 {
 764         /*
 765          * We're currently not called from a shrinker, so put_pages()
 766          * typically means the object is about to destroyed, or called
 767          * from move_notify(). So just avoid doing much for now.
 768          * If the object is not destroyed next, The TTM eviction logic
 769          * and shrinkers will move it out if needed.
 770          */
 771
 772         if (obj->mm.rsgt)
 773                 i915_refct_sgt_put(fetch_and_zero(&obj->mm.rsgt));
 774 }
 775
 776 /**
 777  * i915_ttm_adjust_lru - Adjust an object's position on relevant LRU lists.
 778  * @obj: The object
 779  */
 780 void i915_ttm_adjust_lru(struct drm_i915_gem_object *obj)
 781 {
 782         struct ttm_buffer_object *bo = i915_gem_to_ttm(obj);
 783         struct i915_ttm_tt *i915_tt =
 784                 container_of(bo->ttm, typeof(*i915_tt), ttm);
 785         bool shrinkable =
 786                 bo->ttm && i915_tt->filp && ttm_tt_is_populated(bo->ttm);
 787
 788         /*
 789          * Don't manipulate the TTM LRUs while in TTM bo destruction.
 790          * We're called through i915_ttm_delete_mem_notify().
 791          */
 792         if (!kref_read(&bo->kref))
 793                 return;
 794
 795         /*
 796          * We skip managing the shrinker LRU in set_pages() and just manage
 797          * everything here. This does at least solve the issue with having
 798          * temporary shmem mappings(like with evicted lmem) not being visible to
 799          * the shrinker. Only our shmem objects are shrinkable, everything else
 800          * we keep as unshrinkable.
 801          *
 802          * To make sure everything plays nice we keep an extra shrink pin in TTM
 803          * if the underlying pages are not currently shrinkable. Once we release
 804          * our pin, like when the pages are moved to shmem, the pages will then
 805          * be added to the shrinker LRU, assuming the caller isn't also holding
 806          * a pin.
 807          *
 808          * TODO: consider maybe also bumping the shrinker list here when we have
 809          * already unpinned it, which should give us something more like an LRU.
 810          *
 811          * TODO: There is a small window of opportunity for this function to
 812          * get called from eviction after we've dropped the last GEM refcount,
 813          * but before the TTM deleted flag is set on the object. Avoid
 814          * adjusting the shrinker list in such cases, since the object is
 815          * not available to the shrinker anyway due to its zero refcount.
 816          * To fix this properly we should move to a TTM shrinker LRU list for
 817          * these objects.
 818          */
 819         if (kref_get_unless_zero(&obj->base.refcount)) {
 820                 if (shrinkable != obj->mm.ttm_shrinkable) {
 821                         if (shrinkable) {
 822                                 if (obj->mm.madv == I915_MADV_WILLNEED)
 823                                         __i915_gem_object_make_shrinkable(obj);
 824                                 else
 825                                         __i915_gem_object_make_purgeable(obj);
 826                         } else {
 827                                 i915_gem_object_make_unshrinkable(obj);
 828                         }
 829
 830                         obj->mm.ttm_shrinkable = shrinkable;
 831                 }
 832                 i915_gem_object_put(obj);
 833         }
 834
 835         /*
 836          * Put on the correct LRU list depending on the MADV status
 837          */
 838         spin_lock(&bo->bdev->lru_lock);
 839         if (shrinkable) {
 840                 /* Try to keep shmem_tt from being considered for shrinking. */
 841                 bo->priority = TTM_MAX_BO_PRIORITY - 1;
 842         } else if (obj->mm.madv != I915_MADV_WILLNEED) {
 843                 bo->priority = I915_TTM_PRIO_PURGE;
 844         } else if (!i915_gem_object_has_pages(obj)) {
 845                 if (bo->priority < I915_TTM_PRIO_HAS_PAGES)
 846                         bo->priority = I915_TTM_PRIO_HAS_PAGES;
 847         } else {
 848                 if (bo->priority > I915_TTM_PRIO_NO_PAGES)
 849                         bo->priority = I915_TTM_PRIO_NO_PAGES;
 850         }
 851
 852         ttm_bo_move_to_lru_tail(bo, bo->resource, NULL);
 853         spin_unlock(&bo->bdev->lru_lock);
 854 }
 855
 856 /*
 857  * TTM-backed gem object destruction requires some clarification.
 858  * Basically we have two possibilities here. We can either rely on the
 859  * i915 delayed destruction and put the TTM object when the object
 860  * is idle. This would be detected by TTM which would bypass the
 861  * TTM delayed destroy handling. The other approach is to put the TTM
 862  * object early and rely on the TTM destroyed handling, and then free
 863  * the leftover parts of the GEM object once TTM's destroyed list handling is
 864  * complete. For now, we rely on the latter for two reasons:
 865  * a) TTM can evict an object even when it's on the delayed destroy list,
 866  * which in theory allows for complete eviction.
 867  * b) There is work going on in TTM to allow freeing an object even when
 868  * it's not idle, and using the TTM destroyed list handling could help us
 869  * benefit from that.
 870  */
 871 static void i915_ttm_delayed_free(struct drm_i915_gem_object *obj)
 872 {
 873         GEM_BUG_ON(!obj->ttm.created);
 874
 875         ttm_bo_put(i915_gem_to_ttm(obj));
 876 }
 877
 878 static vm_fault_t vm_fault_ttm(struct vm_fault *vmf)
 879 {
 880         struct vm_area_struct *area = vmf->vma;
 881         struct ttm_buffer_object *bo = area->vm_private_data;
 882         struct drm_device *dev = bo->base.dev;
 883         struct drm_i915_gem_object *obj;
 884         vm_fault_t ret;
 885         int idx;
 886
 887         obj = i915_ttm_to_gem(bo);
 888         if (!obj)
 889                 return VM_FAULT_SIGBUS;
 890
 891         /* Sanity check that we allow writing into this object */
 892         if (unlikely(i915_gem_object_is_readonly(obj) &&
 893                      area->vm_flags & VM_WRITE))
 894                 return VM_FAULT_SIGBUS;
 895
 896         ret = ttm_bo_vm_reserve(bo, vmf);
 897         if (ret)
 898                 return ret;
 899
 900         if (obj->mm.madv != I915_MADV_WILLNEED) {
 901                 dma_resv_unlock(bo->base.resv);
 902                 return VM_FAULT_SIGBUS;
 903         }
 904
 905         if (drm_dev_enter(dev, &idx)) {
 906                 ret = ttm_bo_vm_fault_reserved(vmf, vmf->vma->vm_page_prot,
 907                                                TTM_BO_VM_NUM_PREFAULT);
 908                 drm_dev_exit(idx);
 909         } else {
 910                 ret = ttm_bo_vm_dummy_page(vmf, vmf->vma->vm_page_prot);
 911         }
 912         if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT))
 913                 return ret;
 914
 915         i915_ttm_adjust_lru(obj);
 916
 917         dma_resv_unlock(bo->base.resv);
 918         return ret;
 919 }
 920
 921 static int
 922 vm_access_ttm(struct vm_area_struct *area, unsigned long addr,
 923               void *buf, int len, int write)
 924 {
 925         struct drm_i915_gem_object *obj =
 926                 i915_ttm_to_gem(area->vm_private_data);
 927
 928         if (i915_gem_object_is_readonly(obj) && write)
 929                 return -EACCES;
 930
 931         return ttm_bo_vm_access(area, addr, buf, len, write);
 932 }
 933
 934 static void ttm_vm_open(struct vm_area_struct *vma)
 935 {
 936         struct drm_i915_gem_object *obj =
 937                 i915_ttm_to_gem(vma->vm_private_data);
 938
 939         GEM_BUG_ON(!obj);
 940         i915_gem_object_get(obj);
 941 }
 942
 943 static void ttm_vm_close(struct vm_area_struct *vma)
 944 {
 945         struct drm_i915_gem_object *obj =
 946                 i915_ttm_to_gem(vma->vm_private_data);
 947
 948         GEM_BUG_ON(!obj);
 949         i915_gem_object_put(obj);
 950 }
 951
 952 static const struct vm_operations_struct vm_ops_ttm = {
 953         .fault = vm_fault_ttm,
 954         .access = vm_access_ttm,
 955         .open = ttm_vm_open,
 956         .close = ttm_vm_close,
 957 };
 958
 959 static u64 i915_ttm_mmap_offset(struct drm_i915_gem_object *obj)
 960 {
 961         /* The ttm_bo must be allocated with I915_BO_ALLOC_USER */
 962         GEM_BUG_ON(!drm_mm_node_allocated(&obj->base.vma_node.vm_node));
 963
 964         return drm_vma_node_offset_addr(&obj->base.vma_node);
 965 }
 966
 967 static void i915_ttm_unmap_virtual(struct drm_i915_gem_object *obj)
 968 {
 969         ttm_bo_unmap_virtual(i915_gem_to_ttm(obj));
 970 }
 971
 972 static const struct drm_i915_gem_object_ops i915_gem_ttm_obj_ops = {
 973         .name = "i915_gem_object_ttm",
 974         .flags = I915_GEM_OBJECT_IS_SHRINKABLE |
 975                  I915_GEM_OBJECT_SELF_MANAGED_SHRINK_LIST,
 976
 977         .get_pages = i915_ttm_get_pages,
 978         .put_pages = i915_ttm_put_pages,
 979         .truncate = i915_ttm_truncate,
 980         .shrinker_release_pages = i915_ttm_shrinker_release_pages,
 981
 982         .adjust_lru = i915_ttm_adjust_lru,
 983         .delayed_free = i915_ttm_delayed_free,
 984         .migrate = i915_ttm_migrate,
 985
 986         .mmap_offset = i915_ttm_mmap_offset,
 987         .unmap_virtual = i915_ttm_unmap_virtual,
 988         .mmap_ops = &vm_ops_ttm,
 989 };
 990
 991 void i915_ttm_bo_destroy(struct ttm_buffer_object *bo)
 992 {
 993         struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo);
 994
 995         i915_gem_object_release_memory_region(obj);
 996         mutex_destroy(&obj->ttm.get_io_page.lock);
 997
 998         if (obj->ttm.created) {
 999                 /*
1000                  * We freely manage the shrinker LRU outide of the mm.pages life
1001                  * cycle. As a result when destroying the object we should be
1002                  * extra paranoid and ensure we remove it from the LRU, before
1003                  * we free the object.
1004                  *
1005                  * Touching the ttm_shrinkable outside of the object lock here
1006                  * should be safe now that the last GEM object ref was dropped.
1007                  */
1008                 if (obj->mm.ttm_shrinkable)
1009                         i915_gem_object_make_unshrinkable(obj);
1010
1011                 i915_ttm_backup_free(obj);
1012
1013                 /* This releases all gem object bindings to the backend. */
1014                 __i915_gem_free_object(obj);
1015
1016                 call_rcu(&obj->rcu, __i915_gem_free_object_rcu);
1017         } else {
1018                 __i915_gem_object_fini(obj);
1019         }
1020 }
1021
1022 /**
1023  * __i915_gem_ttm_object_init - Initialize a ttm-backed i915 gem object
1024  * @mem: The initial memory region for the object.
1025  * @obj: The gem object.
1026  * @size: Object size in bytes.
1027  * @flags: gem object flags.
1028  *
1029  * Return: 0 on success, negative error code on failure.
1030  */
1031 int __i915_gem_ttm_object_init(struct intel_memory_region *mem,
1032                                struct drm_i915_gem_object *obj,
1033                                resource_size_t size,
1034                                resource_size_t page_size,
1035                                unsigned int flags)
1036 {
1037         static struct lock_class_key lock_class;
1038         struct drm_i915_private *i915 = mem->i915;
1039         struct ttm_operation_ctx ctx = {
1040                 .interruptible = true,
1041                 .no_wait_gpu = false,
1042         };
1043         enum ttm_bo_type bo_type;
1044         int ret;
1045
1046         drm_gem_private_object_init(&i915->drm, &obj->base, size);
1047         i915_gem_object_init(obj, &i915_gem_ttm_obj_ops, &lock_class, flags);
1048
1049         /* Don't put on a region list until we're either locked or fully initialized. */
1050         obj->mm.region = mem;
1051         INIT_LIST_HEAD(&obj->mm.region_link);
1052
1053         INIT_RADIX_TREE(&obj->ttm.get_io_page.radix, GFP_KERNEL | __GFP_NOWARN);
1054         mutex_init(&obj->ttm.get_io_page.lock);
1055         bo_type = (obj->flags & I915_BO_ALLOC_USER) ? ttm_bo_type_device :
1056                 ttm_bo_type_kernel;
1057
1058         obj->base.vma_node.driver_private = i915_gem_to_ttm(obj);
1059
1060         /* Forcing the page size is kernel internal only */
1061         GEM_BUG_ON(page_size && obj->mm.n_placements);
1062
1063         /*
1064          * Keep an extra shrink pin to prevent the object from being made
1065          * shrinkable too early. If the ttm_tt is ever allocated in shmem, we
1066          * drop the pin. The TTM backend manages the shrinker LRU itself,
1067          * outside of the normal mm.pages life cycle.
1068          */
1069         i915_gem_object_make_unshrinkable(obj);
1070
1071         /*
1072          * If this function fails, it will call the destructor, but
1073          * our caller still owns the object. So no freeing in the
1074          * destructor until obj->ttm.created is true.
1075          * Similarly, in delayed_destroy, we can't call ttm_bo_put()
1076          * until successful initialization.
1077          */
1078         ret = ttm_bo_init_reserved(&i915->bdev, i915_gem_to_ttm(obj), size,
1079                                    bo_type, &i915_sys_placement,
1080                                    page_size >> PAGE_SHIFT,
1081                                    &ctx, NULL, NULL, i915_ttm_bo_destroy);
1082         if (ret)
1083                 return i915_ttm_err_to_gem(ret);
1084
1085         obj->ttm.created = true;
1086         i915_gem_object_release_memory_region(obj);
1087         i915_gem_object_init_memory_region(obj, mem);
1088         i915_ttm_adjust_domains_after_move(obj);
1089         i915_ttm_adjust_gem_after_move(obj);
1090         i915_gem_object_unlock(obj);
1091
1092         return 0;
1093 }
1094
1095 static const struct intel_memory_region_ops ttm_system_region_ops = {
1096         .init_object = __i915_gem_ttm_object_init,
1097         .release = intel_region_ttm_fini,
1098 };
1099
1100 struct intel_memory_region *
1101 i915_gem_ttm_system_setup(struct drm_i915_private *i915,
1102                           u16 type, u16 instance)
1103 {
1104         struct intel_memory_region *mr;
1105
1106         mr = intel_memory_region_create(i915, 0,
1107                                         totalram_pages() << PAGE_SHIFT,
1108                                         PAGE_SIZE, 0,
1109                                         type, instance,
1110                                         &ttm_system_region_ops);
1111         if (IS_ERR(mr))
1112                 return mr;
1113
1114         intel_memory_region_set_name(mr, "system-ttm");
1115         return mr;
1116 }