drivers/gpu/drm/vmwgfx/vmwgfx_mob.c

   1 /**************************************************************************
   2  *
   3  * Copyright © 2012 VMware, Inc., Palo Alto, CA., USA
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  21  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  22  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  23  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  24  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27
  28 #include "vmwgfx_drv.h"
  29
  30 /*
  31  * Currently the MOB interface does not support 64-bit page frame numbers.
  32  * This might change in the future to be similar to the GMR2 interface
  33  * when virtual machines support memory beyond 16TB.
  34  */
  35
  36 #define VMW_PPN_SIZE 4
  37
  38 /*
  39  * struct vmw_mob - Structure containing page table and metadata for a
  40  * Guest Memory OBject.
  41  *
  42  * @num_pages       Number of pages that make up the page table.
  43  * @pt_level        The indirection level of the page table. 0-2.
  44  * @pt_root_page    DMA address of the level 0 page of the page table.
  45  */
  46 struct vmw_mob {
  47         struct ttm_buffer_object *pt_bo;
  48         unsigned long num_pages;
  49         unsigned pt_level;
  50         dma_addr_t pt_root_page;
  51         uint32_t id;
  52 };
  53
  54 /*
  55  * struct vmw_otable - Guest Memory OBject table metadata
  56  *
  57  * @size:           Size of the table (page-aligned).
  58  * @page_table:     Pointer to a struct vmw_mob holding the page table.
  59  */
  60 struct vmw_otable {
  61         unsigned long size;
  62         struct vmw_mob *page_table;
  63 };
  64
  65 static int vmw_mob_pt_populate(struct vmw_private *dev_priv,
  66                                struct vmw_mob *mob);
  67 static void vmw_mob_pt_setup(struct vmw_mob *mob,
  68                              struct vmw_piter data_iter,
  69                              unsigned long num_data_pages);
  70
  71 /*
  72  * vmw_setup_otable_base - Issue an object table base setup command to
  73  * the device
  74  *
  75  * @dev_priv:       Pointer to a device private structure
  76  * @type:           Type of object table base
  77  * @offset          Start of table offset into dev_priv::otable_bo
  78  * @otable          Pointer to otable metadata;
  79  *
  80  * This function returns -ENOMEM if it fails to reserve fifo space,
  81  * and may block waiting for fifo space.
  82  */
  83 static int vmw_setup_otable_base(struct vmw_private *dev_priv,
  84                                  SVGAOTableType type,
  85                                  unsigned long offset,
  86                                  struct vmw_otable *otable)
  87 {
  88         struct {
  89                 SVGA3dCmdHeader header;
  90                 SVGA3dCmdSetOTableBase body;
  91         } *cmd;
  92         struct vmw_mob *mob;
  93         const struct vmw_sg_table *vsgt;
  94         struct vmw_piter iter;
  95         int ret;
  96
  97         BUG_ON(otable->page_table != NULL);
  98
  99         vsgt = vmw_bo_sg_table(dev_priv->otable_bo);
 100         vmw_piter_start(&iter, vsgt, offset >> PAGE_SHIFT);
 101         WARN_ON(!vmw_piter_next(&iter));
 102
 103         mob = vmw_mob_create(otable->size >> PAGE_SHIFT);
 104         if (unlikely(mob == NULL)) {
 105                 DRM_ERROR("Failed creating OTable page table.\n");
 106                 return -ENOMEM;
 107         }
 108
 109         if (otable->size <= PAGE_SIZE) {
 110                 mob->pt_level = SVGA3D_MOBFMT_PTDEPTH_0;
 111                 mob->pt_root_page = vmw_piter_dma_addr(&iter);
 112         } else if (vsgt->num_regions == 1) {
 113                 mob->pt_level = SVGA3D_MOBFMT_RANGE;
 114                 mob->pt_root_page = vmw_piter_dma_addr(&iter);
 115         } else {
 116                 ret = vmw_mob_pt_populate(dev_priv, mob);
 117                 if (unlikely(ret != 0))
 118                         goto out_no_populate;
 119
 120                 vmw_mob_pt_setup(mob, iter, otable->size >> PAGE_SHIFT);
 121         }
 122
 123         cmd = vmw_fifo_reserve(dev_priv, sizeof(*cmd));
 124         if (unlikely(cmd == NULL)) {
 125                 DRM_ERROR("Failed reserving FIFO space for OTable setup.\n");
 126                 goto out_no_fifo;
 127         }
 128
 129         memset(cmd, 0, sizeof(*cmd));
 130         cmd->header.id = SVGA_3D_CMD_SET_OTABLE_BASE;
 131         cmd->header.size = sizeof(cmd->body);
 132         cmd->body.type = type;
 133         cmd->body.baseAddress = mob->pt_root_page >> PAGE_SHIFT;
 134         cmd->body.sizeInBytes = otable->size;
 135         cmd->body.validSizeInBytes = 0;
 136         cmd->body.ptDepth = mob->pt_level;
 137
 138         vmw_fifo_commit(dev_priv, sizeof(*cmd));
 139         otable->page_table = mob;
 140
 141         return 0;
 142
 143 out_no_fifo:
 144 out_no_populate:
 145         vmw_mob_destroy(mob);
 146         return ret;
 147 }
 148
 149 /*
 150  * vmw_takedown_otable_base - Issue an object table base takedown command
 151  * to the device
 152  *
 153  * @dev_priv:       Pointer to a device private structure
 154  * @type:           Type of object table base
 155  *
 156  */
 157 static void vmw_takedown_otable_base(struct vmw_private *dev_priv,
 158                                      SVGAOTableType type,
 159                                      struct vmw_otable *otable)
 160 {
 161         struct {
 162                 SVGA3dCmdHeader header;
 163                 SVGA3dCmdSetOTableBase body;
 164         } *cmd;
 165         struct ttm_buffer_object *bo = otable->page_table->pt_bo;
 166
 167         if (otable->page_table == NULL)
 168                 return;
 169
 170         cmd = vmw_fifo_reserve(dev_priv, sizeof(*cmd));
 171         if (unlikely(cmd == NULL))
 172                 DRM_ERROR("Failed reserving FIFO space for OTable setup.\n");
 173
 174         memset(cmd, 0, sizeof(*cmd));
 175         cmd->header.id = SVGA_3D_CMD_SET_OTABLE_BASE;
 176         cmd->header.size = sizeof(cmd->body);
 177         cmd->body.type = type;
 178         cmd->body.baseAddress = 0;
 179         cmd->body.sizeInBytes = 0;
 180         cmd->body.validSizeInBytes = 0;
 181         cmd->body.ptDepth = SVGA3D_MOBFMT_INVALID;
 182         vmw_fifo_commit(dev_priv, sizeof(*cmd));
 183
 184         if (bo) {
 185                 int ret;
 186
 187                 ret = ttm_bo_reserve(bo, false, true, false, false);
 188                 BUG_ON(ret != 0);
 189
 190                 vmw_fence_single_bo(bo, NULL);
 191                 ttm_bo_unreserve(bo);
 192         }
 193
 194         vmw_mob_destroy(otable->page_table);
 195         otable->page_table = NULL;
 196 }
 197
 198 /*
 199  * vmw_otables_setup - Set up guest backed memory object tables
 200  *
 201  * @dev_priv:       Pointer to a device private structure
 202  *
 203  * Takes care of the device guest backed surface
 204  * initialization, by setting up the guest backed memory object tables.
 205  * Returns 0 on success and various error codes on failure. A succesful return
 206  * means the object tables can be taken down using the vmw_otables_takedown
 207  * function.
 208  */
 209 int vmw_otables_setup(struct vmw_private *dev_priv)
 210 {
 211         unsigned long offset;
 212         unsigned long bo_size;
 213         struct vmw_otable *otables;
 214         SVGAOTableType i;
 215         int ret;
 216
 217         otables = kzalloc(SVGA_OTABLE_COUNT * sizeof(*otables),
 218                           GFP_KERNEL);
 219         if (unlikely(otables == NULL)) {
 220                 DRM_ERROR("Failed to allocate space for otable "
 221                           "metadata.\n");
 222                 return -ENOMEM;
 223         }
 224
 225         otables[SVGA_OTABLE_MOB].size =
 226                 VMWGFX_NUM_MOB * SVGA3D_OTABLE_MOB_ENTRY_SIZE;
 227         otables[SVGA_OTABLE_SURFACE].size =
 228                 VMWGFX_NUM_GB_SURFACE * SVGA3D_OTABLE_SURFACE_ENTRY_SIZE;
 229         otables[SVGA_OTABLE_CONTEXT].size =
 230                 VMWGFX_NUM_GB_CONTEXT * SVGA3D_OTABLE_CONTEXT_ENTRY_SIZE;
 231         otables[SVGA_OTABLE_SHADER].size =
 232                 VMWGFX_NUM_GB_SHADER * SVGA3D_OTABLE_SHADER_ENTRY_SIZE;
 233
 234         bo_size = 0;
 235         for (i = 0; i < SVGA_OTABLE_COUNT; ++i) {
 236                 otables[i].size =
 237                         (otables[i].size + PAGE_SIZE - 1) & PAGE_MASK;
 238                 bo_size += otables[i].size;
 239         }
 240
 241         ret = ttm_bo_create(&dev_priv->bdev, bo_size,
 242                             ttm_bo_type_device,
 243                             &vmw_sys_ne_placement,
 244                             0, false, NULL,
 245                             &dev_priv->otable_bo);
 246
 247         if (unlikely(ret != 0))
 248                 goto out_no_bo;
 249
 250         ret = ttm_bo_reserve(dev_priv->otable_bo, false, true, false, false);
 251         BUG_ON(ret != 0);
 252         ret = vmw_bo_driver.ttm_tt_populate(dev_priv->otable_bo->ttm);
 253         if (unlikely(ret != 0))
 254                 goto out_unreserve;
 255         ret = vmw_bo_map_dma(dev_priv->otable_bo);
 256         if (unlikely(ret != 0))
 257                 goto out_unreserve;
 258
 259         ttm_bo_unreserve(dev_priv->otable_bo);
 260
 261         offset = 0;
 262         for (i = 0; i < SVGA_OTABLE_COUNT; ++i) {
 263                 ret = vmw_setup_otable_base(dev_priv, i, offset,
 264                                             &otables[i]);
 265                 if (unlikely(ret != 0))
 266                         goto out_no_setup;
 267                 offset += otables[i].size;
 268         }
 269
 270         dev_priv->otables = otables;
 271         return 0;
 272
 273 out_unreserve:
 274         ttm_bo_unreserve(dev_priv->otable_bo);
 275 out_no_setup:
 276         for (i = 0; i < SVGA_OTABLE_COUNT; ++i)
 277                 vmw_takedown_otable_base(dev_priv, i, &otables[i]);
 278
 279         ttm_bo_unref(&dev_priv->otable_bo);
 280 out_no_bo:
 281         kfree(otables);
 282         return ret;
 283 }
 284
 285
 286 /*
 287  * vmw_otables_takedown - Take down guest backed memory object tables
 288  *
 289  * @dev_priv:       Pointer to a device private structure
 290  *
 291  * Take down the Guest Memory Object tables.
 292  */
 293 void vmw_otables_takedown(struct vmw_private *dev_priv)
 294 {
 295         SVGAOTableType i;
 296         struct ttm_buffer_object *bo = dev_priv->otable_bo;
 297         int ret;
 298
 299         for (i = 0; i < SVGA_OTABLE_COUNT; ++i)
 300                 vmw_takedown_otable_base(dev_priv, i,
 301                                          &dev_priv->otables[i]);
 302
 303         ret = ttm_bo_reserve(bo, false, true, false, false);
 304         BUG_ON(ret != 0);
 305
 306         vmw_fence_single_bo(bo, NULL);
 307         ttm_bo_unreserve(bo);
 308
 309         ttm_bo_unref(&dev_priv->otable_bo);
 310         kfree(dev_priv->otables);
 311         dev_priv->otables = NULL;
 312 }
 313
 314
 315 /*
 316  * vmw_mob_calculate_pt_pages - Calculate the number of page table pages
 317  * needed for a guest backed memory object.
 318  *
 319  * @data_pages:  Number of data pages in the memory object buffer.
 320  */
 321 static unsigned long vmw_mob_calculate_pt_pages(unsigned long data_pages)
 322 {
 323         unsigned long data_size = data_pages * PAGE_SIZE;
 324         unsigned long tot_size = 0;
 325
 326         while (likely(data_size > PAGE_SIZE)) {
 327                 data_size = DIV_ROUND_UP(data_size, PAGE_SIZE);
 328                 data_size *= VMW_PPN_SIZE;
 329                 tot_size += (data_size + PAGE_SIZE - 1) & PAGE_MASK;
 330         }
 331
 332         return tot_size >> PAGE_SHIFT;
 333 }
 334
 335 /*
 336  * vmw_mob_create - Create a mob, but don't populate it.
 337  *
 338  * @data_pages:  Number of data pages of the underlying buffer object.
 339  */
 340 struct vmw_mob *vmw_mob_create(unsigned long data_pages)
 341 {
 342         struct vmw_mob *mob = kzalloc(sizeof(*mob), GFP_KERNEL);
 343
 344         if (unlikely(mob == NULL))
 345                 return NULL;
 346
 347         mob->num_pages = vmw_mob_calculate_pt_pages(data_pages);
 348
 349         return mob;
 350 }
 351
 352 /*
 353  * vmw_mob_pt_populate - Populate the mob pagetable
 354  *
 355  * @mob:         Pointer to the mob the pagetable of which we want to
 356  *               populate.
 357  *
 358  * This function allocates memory to be used for the pagetable, and
 359  * adjusts TTM memory accounting accordingly. Returns ENOMEM if
 360  * memory resources aren't sufficient and may cause TTM buffer objects
 361  * to be swapped out by using the TTM memory accounting function.
 362  */
 363 static int vmw_mob_pt_populate(struct vmw_private *dev_priv,
 364                                struct vmw_mob *mob)
 365 {
 366         int ret;
 367         BUG_ON(mob->pt_bo != NULL);
 368
 369         ret = ttm_bo_create(&dev_priv->bdev, mob->num_pages * PAGE_SIZE,
 370                             ttm_bo_type_device,
 371                             &vmw_sys_ne_placement,
 372                             0, false, NULL, &mob->pt_bo);
 373         if (unlikely(ret != 0))
 374                 return ret;
 375
 376         ret = ttm_bo_reserve(mob->pt_bo, false, true, false, false);
 377
 378         BUG_ON(ret != 0);
 379         ret = vmw_bo_driver.ttm_tt_populate(mob->pt_bo->ttm);
 380         if (unlikely(ret != 0))
 381                 goto out_unreserve;
 382         ret = vmw_bo_map_dma(mob->pt_bo);
 383         if (unlikely(ret != 0))
 384                 goto out_unreserve;
 385
 386         ttm_bo_unreserve(mob->pt_bo);
 387
 388         return 0;
 389
 390 out_unreserve:
 391         ttm_bo_unreserve(mob->pt_bo);
 392         ttm_bo_unref(&mob->pt_bo);
 393
 394         return ret;
 395 }
 396
 397
 398 /*
 399  * vmw_mob_build_pt - Build a pagetable
 400  *
 401  * @data_addr:      Array of DMA addresses to the underlying buffer
 402  *                  object's data pages.
 403  * @num_data_pages: Number of buffer object data pages.
 404  * @pt_pages:       Array of page pointers to the page table pages.
 405  *
 406  * Returns the number of page table pages actually used.
 407  * Uses atomic kmaps of highmem pages to avoid TLB thrashing.
 408  */
 409 static unsigned long vmw_mob_build_pt(struct vmw_piter *data_iter,
 410                                       unsigned long num_data_pages,
 411                                       struct vmw_piter *pt_iter)
 412 {
 413         unsigned long pt_size = num_data_pages * VMW_PPN_SIZE;
 414         unsigned long num_pt_pages = DIV_ROUND_UP(pt_size, PAGE_SIZE);
 415         unsigned long pt_page;
 416         uint32_t *addr, *save_addr;
 417         unsigned long i;
 418         struct page *page;
 419
 420         for (pt_page = 0; pt_page < num_pt_pages; ++pt_page) {
 421                 page = vmw_piter_page(pt_iter);
 422
 423                 save_addr = addr = kmap_atomic(page);
 424
 425                 for (i = 0; i < PAGE_SIZE / VMW_PPN_SIZE; ++i) {
 426                         u32 tmp = vmw_piter_dma_addr(data_iter) >> PAGE_SHIFT;
 427                         *addr++ = tmp;
 428                         if (unlikely(--num_data_pages == 0))
 429                                 break;
 430                         WARN_ON(!vmw_piter_next(data_iter));
 431                 }
 432                 kunmap_atomic(save_addr);
 433                 vmw_piter_next(pt_iter);
 434         }
 435
 436         return num_pt_pages;
 437 }
 438
 439 /*
 440  * vmw_mob_build_pt - Set up a multilevel mob pagetable
 441  *
 442  * @mob:            Pointer to a mob whose page table needs setting up.
 443  * @data_addr       Array of DMA addresses to the buffer object's data
 444  *                  pages.
 445  * @num_data_pages: Number of buffer object data pages.
 446  *
 447  * Uses tail recursion to set up a multilevel mob page table.
 448  */
 449 static void vmw_mob_pt_setup(struct vmw_mob *mob,
 450                              struct vmw_piter data_iter,
 451                              unsigned long num_data_pages)
 452 {
 453         unsigned long num_pt_pages = 0;
 454         struct ttm_buffer_object *bo = mob->pt_bo;
 455         struct vmw_piter save_pt_iter;
 456         struct vmw_piter pt_iter;
 457         const struct vmw_sg_table *vsgt;
 458         int ret;
 459
 460         ret = ttm_bo_reserve(bo, false, true, false, 0);
 461         BUG_ON(ret != 0);
 462
 463         vsgt = vmw_bo_sg_table(bo);
 464         vmw_piter_start(&pt_iter, vsgt, 0);
 465         BUG_ON(!vmw_piter_next(&pt_iter));
 466         mob->pt_level = 0;
 467         while (likely(num_data_pages > 1)) {
 468                 ++mob->pt_level;
 469                 BUG_ON(mob->pt_level > 2);
 470                 save_pt_iter = pt_iter;
 471                 num_pt_pages = vmw_mob_build_pt(&data_iter, num_data_pages,
 472                                                 &pt_iter);
 473                 data_iter = save_pt_iter;
 474                 num_data_pages = num_pt_pages;
 475         }
 476
 477         mob->pt_root_page = vmw_piter_dma_addr(&save_pt_iter);
 478         ttm_bo_unreserve(bo);
 479 }
 480
 481 /*
 482  * vmw_mob_destroy - Destroy a mob, unpopulating first if necessary.
 483  *
 484  * @mob:            Pointer to a mob to destroy.
 485  */
 486 void vmw_mob_destroy(struct vmw_mob *mob)
 487 {
 488         if (mob->pt_bo)
 489                 ttm_bo_unref(&mob->pt_bo);
 490         kfree(mob);
 491 }
 492
 493 /*
 494  * vmw_mob_unbind - Hide a mob from the device.
 495  *
 496  * @dev_priv:       Pointer to a device private.
 497  * @mob_id:         Device id of the mob to unbind.
 498  */
 499 void vmw_mob_unbind(struct vmw_private *dev_priv,
 500                     struct vmw_mob *mob)
 501 {
 502         struct {
 503                 SVGA3dCmdHeader header;
 504                 SVGA3dCmdDestroyGBMob body;
 505         } *cmd;
 506         int ret;
 507         struct ttm_buffer_object *bo = mob->pt_bo;
 508
 509         if (bo) {
 510                 ret = ttm_bo_reserve(bo, false, true, false, 0);
 511                 /*
 512                  * Noone else should be using this buffer.
 513                  */
 514                 BUG_ON(ret != 0);
 515         }
 516
 517         cmd = vmw_fifo_reserve(dev_priv, sizeof(*cmd));
 518         if (unlikely(cmd == NULL)) {
 519                 DRM_ERROR("Failed reserving FIFO space for Memory "
 520                           "Object unbinding.\n");
 521         }
 522         cmd->header.id = SVGA_3D_CMD_DESTROY_GB_MOB;
 523         cmd->header.size = sizeof(cmd->body);
 524         cmd->body.mobid = mob->id;
 525         vmw_fifo_commit(dev_priv, sizeof(*cmd));
 526         if (bo) {
 527                 vmw_fence_single_bo(bo, NULL);
 528                 ttm_bo_unreserve(bo);
 529         }
 530         vmw_3d_resource_dec(dev_priv, false);
 531 }
 532
 533 /*
 534  * vmw_mob_bind - Make a mob visible to the device after first
 535  *                populating it if necessary.
 536  *
 537  * @dev_priv:       Pointer to a device private.
 538  * @mob:            Pointer to the mob we're making visible.
 539  * @data_addr:      Array of DMA addresses to the data pages of the underlying
 540  *                  buffer object.
 541  * @num_data_pages: Number of data pages of the underlying buffer
 542  *                  object.
 543  * @mob_id:         Device id of the mob to bind
 544  *
 545  * This function is intended to be interfaced with the ttm_tt backend
 546  * code.
 547  */
 548 int vmw_mob_bind(struct vmw_private *dev_priv,
 549                  struct vmw_mob *mob,
 550                  const struct vmw_sg_table *vsgt,
 551                  unsigned long num_data_pages,
 552                  int32_t mob_id)
 553 {
 554         int ret;
 555         bool pt_set_up = false;
 556         struct vmw_piter data_iter;
 557         struct {
 558                 SVGA3dCmdHeader header;
 559                 SVGA3dCmdDefineGBMob body;
 560         } *cmd;
 561
 562         mob->id = mob_id;
 563         vmw_piter_start(&data_iter, vsgt, 0);
 564         if (unlikely(!vmw_piter_next(&data_iter)))
 565                 return 0;
 566
 567         if (likely(num_data_pages == 1)) {
 568                 mob->pt_level = SVGA3D_MOBFMT_PTDEPTH_0;
 569                 mob->pt_root_page = vmw_piter_dma_addr(&data_iter);
 570         } else if (vsgt->num_regions == 1) {
 571                 mob->pt_level = SVGA3D_MOBFMT_RANGE;
 572                 mob->pt_root_page = vmw_piter_dma_addr(&data_iter);
 573         } else if (unlikely(mob->pt_bo == NULL)) {
 574                 ret = vmw_mob_pt_populate(dev_priv, mob);
 575                 if (unlikely(ret != 0))
 576                         return ret;
 577
 578                 vmw_mob_pt_setup(mob, data_iter, num_data_pages);
 579                 pt_set_up = true;
 580         }
 581
 582         (void) vmw_3d_resource_inc(dev_priv, false);
 583
 584         cmd = vmw_fifo_reserve(dev_priv, sizeof(*cmd));
 585         if (unlikely(cmd == NULL)) {
 586                 DRM_ERROR("Failed reserving FIFO space for Memory "
 587                           "Object binding.\n");
 588                 goto out_no_cmd_space;
 589         }
 590
 591         cmd->header.id = SVGA_3D_CMD_DEFINE_GB_MOB;
 592         cmd->header.size = sizeof(cmd->body);
 593         cmd->body.mobid = mob_id;
 594         cmd->body.ptDepth = mob->pt_level;
 595         cmd->body.base = mob->pt_root_page >> PAGE_SHIFT;
 596         cmd->body.sizeInBytes = num_data_pages * PAGE_SIZE;
 597
 598         vmw_fifo_commit(dev_priv, sizeof(*cmd));
 599
 600         return 0;
 601
 602 out_no_cmd_space:
 603         vmw_3d_resource_dec(dev_priv, false);
 604         if (pt_set_up)
 605                 ttm_bo_unref(&mob->pt_bo);
 606
 607         return -ENOMEM;
 608 }