root/drivers/gpu/drm/i915/gvt/dmabuf.c

DEFINITIONS

1. vgpu_gem_get_pages
2. vgpu_gem_put_pages
3. dmabuf_gem_object_free
4. dmabuf_obj_get
5. dmabuf_obj_put
6. vgpu_gem_release
7. vgpu_create_gem
8. validate_hotspot
9. vgpu_get_plane_info
10. pick_dmabuf_by_info
11. pick_dmabuf_by_num
12. update_fb_info
13. intel_vgpu_query_plane
14. intel_vgpu_get_dmabuf
15. intel_vgpu_dmabuf_cleanup

   1 /*
   2  * Copyright 2017 Intel Corporation. All rights reserved.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *    Zhiyuan Lv <zhiyuan.lv@intel.com>
  25  *
  26  * Contributors:
  27  *    Xiaoguang Chen
  28  *    Tina Zhang <tina.zhang@intel.com>
  29  */
  30 
  31 #include <linux/dma-buf.h>
  32 #include <linux/vfio.h>
  33 
  34 #include "i915_drv.h"
  35 #include "gvt.h"
  36 
  37 #define GEN8_DECODE_PTE(pte) (pte & GENMASK_ULL(63, 12))
  38 
  39 static int vgpu_gem_get_pages(
  40                 struct drm_i915_gem_object *obj)
  41 {
  42         struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
  43         struct sg_table *st;
  44         struct scatterlist *sg;
  45         int i, ret;
  46         gen8_pte_t __iomem *gtt_entries;
  47         struct intel_vgpu_fb_info *fb_info;
  48         u32 page_num;
  49 
  50         fb_info = (struct intel_vgpu_fb_info *)obj->gvt_info;
  51         if (WARN_ON(!fb_info))
  52                 return -ENODEV;
  53 
  54         st = kmalloc(sizeof(*st), GFP_KERNEL);
  55         if (unlikely(!st))
  56                 return -ENOMEM;
  57 
  58         page_num = obj->base.size >> PAGE_SHIFT;
  59         ret = sg_alloc_table(st, page_num, GFP_KERNEL);
  60         if (ret) {
  61                 kfree(st);
  62                 return ret;
  63         }
  64         gtt_entries = (gen8_pte_t __iomem *)dev_priv->ggtt.gsm +
  65                 (fb_info->start >> PAGE_SHIFT);
  66         for_each_sg(st->sgl, sg, page_num, i) {
  67                 sg->offset = 0;
  68                 sg->length = PAGE_SIZE;
  69                 sg_dma_address(sg) =
  70                         GEN8_DECODE_PTE(readq(&gtt_entries[i]));
  71                 sg_dma_len(sg) = PAGE_SIZE;
  72         }
  73 
  74         __i915_gem_object_set_pages(obj, st, PAGE_SIZE);
  75 
  76         return 0;
  77 }
  78 
  79 static void vgpu_gem_put_pages(struct drm_i915_gem_object *obj,
  80                 struct sg_table *pages)
  81 {
  82         sg_free_table(pages);
  83         kfree(pages);
  84 }
  85 
  86 static void dmabuf_gem_object_free(struct kref *kref)
  87 {
  88         struct intel_vgpu_dmabuf_obj *obj =
  89                 container_of(kref, struct intel_vgpu_dmabuf_obj, kref);
  90         struct intel_vgpu *vgpu = obj->vgpu;
  91         struct list_head *pos;
  92         struct intel_vgpu_dmabuf_obj *dmabuf_obj;
  93 
  94         if (vgpu && vgpu->active && !list_empty(&vgpu->dmabuf_obj_list_head)) {
  95                 list_for_each(pos, &vgpu->dmabuf_obj_list_head) {
  96                         dmabuf_obj = container_of(pos,
  97                                         struct intel_vgpu_dmabuf_obj, list);
  98                         if (dmabuf_obj == obj) {
  99                                 list_del(pos);
 100                                 intel_gvt_hypervisor_put_vfio_device(vgpu);
 101                                 idr_remove(&vgpu->object_idr,
 102                                            dmabuf_obj->dmabuf_id);
 103                                 kfree(dmabuf_obj->info);
 104                                 kfree(dmabuf_obj);
 105                                 break;
 106                         }
 107                 }
 108         } else {
 109                 /* Free the orphan dmabuf_objs here */
 110                 kfree(obj->info);
 111                 kfree(obj);
 112         }
 113 }
 114 
 115 
 116 static inline void dmabuf_obj_get(struct intel_vgpu_dmabuf_obj *obj)
 117 {
 118         kref_get(&obj->kref);
 119 }
 120 
 121 static inline void dmabuf_obj_put(struct intel_vgpu_dmabuf_obj *obj)
 122 {
 123         kref_put(&obj->kref, dmabuf_gem_object_free);
 124 }
 125 
 126 static void vgpu_gem_release(struct drm_i915_gem_object *gem_obj)
 127 {
 128 
 129         struct intel_vgpu_fb_info *fb_info = gem_obj->gvt_info;
 130         struct intel_vgpu_dmabuf_obj *obj = fb_info->obj;
 131         struct intel_vgpu *vgpu = obj->vgpu;
 132 
 133         if (vgpu) {
 134                 mutex_lock(&vgpu->dmabuf_lock);
 135                 gem_obj->base.dma_buf = NULL;
 136                 dmabuf_obj_put(obj);
 137                 mutex_unlock(&vgpu->dmabuf_lock);
 138         } else {
 139                 /* vgpu is NULL, as it has been removed already */
 140                 gem_obj->base.dma_buf = NULL;
 141                 dmabuf_obj_put(obj);
 142         }
 143 }
 144 
 145 static const struct drm_i915_gem_object_ops intel_vgpu_gem_ops = {
 146         .flags = I915_GEM_OBJECT_IS_PROXY,
 147         .get_pages = vgpu_gem_get_pages,
 148         .put_pages = vgpu_gem_put_pages,
 149         .release = vgpu_gem_release,
 150 };
 151 
 152 static struct drm_i915_gem_object *vgpu_create_gem(struct drm_device *dev,
 153                 struct intel_vgpu_fb_info *info)
 154 {
 155         struct drm_i915_private *dev_priv = to_i915(dev);
 156         struct drm_i915_gem_object *obj;
 157 
 158         obj = i915_gem_object_alloc();
 159         if (obj == NULL)
 160                 return NULL;
 161 
 162         drm_gem_private_object_init(dev, &obj->base,
 163                 roundup(info->size, PAGE_SIZE));
 164         i915_gem_object_init(obj, &intel_vgpu_gem_ops);
 165 
 166         obj->read_domains = I915_GEM_DOMAIN_GTT;
 167         obj->write_domain = 0;
 168         if (INTEL_GEN(dev_priv) >= 9) {
 169                 unsigned int tiling_mode = 0;
 170                 unsigned int stride = 0;
 171 
 172                 switch (info->drm_format_mod) {
 173                 case DRM_FORMAT_MOD_LINEAR:
 174                         tiling_mode = I915_TILING_NONE;
 175                         break;
 176                 case I915_FORMAT_MOD_X_TILED:
 177                         tiling_mode = I915_TILING_X;
 178                         stride = info->stride;
 179                         break;
 180                 case I915_FORMAT_MOD_Y_TILED:
 181                 case I915_FORMAT_MOD_Yf_TILED:
 182                         tiling_mode = I915_TILING_Y;
 183                         stride = info->stride;
 184                         break;
 185                 default:
 186                         gvt_dbg_core("invalid drm_format_mod %llx for tiling\n",
 187                                      info->drm_format_mod);
 188                 }
 189                 obj->tiling_and_stride = tiling_mode | stride;
 190         } else {
 191                 obj->tiling_and_stride = info->drm_format_mod ?
 192                                         I915_TILING_X : 0;
 193         }
 194 
 195         return obj;
 196 }
 197 
 198 static bool validate_hotspot(struct intel_vgpu_cursor_plane_format *c)
 199 {
 200         if (c && c->x_hot <= c->width && c->y_hot <= c->height)
 201                 return true;
 202         else
 203                 return false;
 204 }
 205 
 206 static int vgpu_get_plane_info(struct drm_device *dev,
 207                 struct intel_vgpu *vgpu,
 208                 struct intel_vgpu_fb_info *info,
 209                 int plane_id)
 210 {
 211         struct intel_vgpu_primary_plane_format p;
 212         struct intel_vgpu_cursor_plane_format c;
 213         int ret, tile_height = 1;
 214 
 215         memset(info, 0, sizeof(*info));
 216 
 217         if (plane_id == DRM_PLANE_TYPE_PRIMARY) {
 218                 ret = intel_vgpu_decode_primary_plane(vgpu, &p);
 219                 if (ret)
 220                         return ret;
 221                 info->start = p.base;
 222                 info->start_gpa = p.base_gpa;
 223                 info->width = p.width;
 224                 info->height = p.height;
 225                 info->stride = p.stride;
 226                 info->drm_format = p.drm_format;
 227 
 228                 switch (p.tiled) {
 229                 case PLANE_CTL_TILED_LINEAR:
 230                         info->drm_format_mod = DRM_FORMAT_MOD_LINEAR;
 231                         break;
 232                 case PLANE_CTL_TILED_X:
 233                         info->drm_format_mod = I915_FORMAT_MOD_X_TILED;
 234                         tile_height = 8;
 235                         break;
 236                 case PLANE_CTL_TILED_Y:
 237                         info->drm_format_mod = I915_FORMAT_MOD_Y_TILED;
 238                         tile_height = 32;
 239                         break;
 240                 case PLANE_CTL_TILED_YF:
 241                         info->drm_format_mod = I915_FORMAT_MOD_Yf_TILED;
 242                         tile_height = 32;
 243                         break;
 244                 default:
 245                         gvt_vgpu_err("invalid tiling mode: %x\n", p.tiled);
 246                 }
 247         } else if (plane_id == DRM_PLANE_TYPE_CURSOR) {
 248                 ret = intel_vgpu_decode_cursor_plane(vgpu, &c);
 249                 if (ret)
 250                         return ret;
 251                 info->start = c.base;
 252                 info->start_gpa = c.base_gpa;
 253                 info->width = c.width;
 254                 info->height = c.height;
 255                 info->stride = c.width * (c.bpp / 8);
 256                 info->drm_format = c.drm_format;
 257                 info->drm_format_mod = 0;
 258                 info->x_pos = c.x_pos;
 259                 info->y_pos = c.y_pos;
 260 
 261                 if (validate_hotspot(&c)) {
 262                         info->x_hot = c.x_hot;
 263                         info->y_hot = c.y_hot;
 264                 } else {
 265                         info->x_hot = UINT_MAX;
 266                         info->y_hot = UINT_MAX;
 267                 }
 268         } else {
 269                 gvt_vgpu_err("invalid plane id:%d\n", plane_id);
 270                 return -EINVAL;
 271         }
 272 
 273         info->size = info->stride * roundup(info->height, tile_height);
 274         if (info->size == 0) {
 275                 gvt_vgpu_err("fb size is zero\n");
 276                 return -EINVAL;
 277         }
 278 
 279         if (info->start & (PAGE_SIZE - 1)) {
 280                 gvt_vgpu_err("Not aligned fb address:0x%llx\n", info->start);
 281                 return -EFAULT;
 282         }
 283 
 284         if (!intel_gvt_ggtt_validate_range(vgpu, info->start, info->size)) {
 285                 gvt_vgpu_err("invalid gma addr\n");
 286                 return -EFAULT;
 287         }
 288 
 289         return 0;
 290 }
 291 
 292 static struct intel_vgpu_dmabuf_obj *
 293 pick_dmabuf_by_info(struct intel_vgpu *vgpu,
 294                     struct intel_vgpu_fb_info *latest_info)
 295 {
 296         struct list_head *pos;
 297         struct intel_vgpu_fb_info *fb_info;
 298         struct intel_vgpu_dmabuf_obj *dmabuf_obj = NULL;
 299         struct intel_vgpu_dmabuf_obj *ret = NULL;
 300 
 301         list_for_each(pos, &vgpu->dmabuf_obj_list_head) {
 302                 dmabuf_obj = container_of(pos, struct intel_vgpu_dmabuf_obj,
 303                                                 list);
 304                 if ((dmabuf_obj == NULL) ||
 305                     (dmabuf_obj->info == NULL))
 306                         continue;
 307 
 308                 fb_info = (struct intel_vgpu_fb_info *)dmabuf_obj->info;
 309                 if ((fb_info->start == latest_info->start) &&
 310                     (fb_info->start_gpa == latest_info->start_gpa) &&
 311                     (fb_info->size == latest_info->size) &&
 312                     (fb_info->drm_format_mod == latest_info->drm_format_mod) &&
 313                     (fb_info->drm_format == latest_info->drm_format) &&
 314                     (fb_info->width == latest_info->width) &&
 315                     (fb_info->height == latest_info->height)) {
 316                         ret = dmabuf_obj;
 317                         break;
 318                 }
 319         }
 320 
 321         return ret;
 322 }
 323 
 324 static struct intel_vgpu_dmabuf_obj *
 325 pick_dmabuf_by_num(struct intel_vgpu *vgpu, u32 id)
 326 {
 327         struct list_head *pos;
 328         struct intel_vgpu_dmabuf_obj *dmabuf_obj = NULL;
 329         struct intel_vgpu_dmabuf_obj *ret = NULL;
 330 
 331         list_for_each(pos, &vgpu->dmabuf_obj_list_head) {
 332                 dmabuf_obj = container_of(pos, struct intel_vgpu_dmabuf_obj,
 333                                                 list);
 334                 if (!dmabuf_obj)
 335                         continue;
 336 
 337                 if (dmabuf_obj->dmabuf_id == id) {
 338                         ret = dmabuf_obj;
 339                         break;
 340                 }
 341         }
 342 
 343         return ret;
 344 }
 345 
 346 static void update_fb_info(struct vfio_device_gfx_plane_info *gvt_dmabuf,
 347                       struct intel_vgpu_fb_info *fb_info)
 348 {
 349         gvt_dmabuf->drm_format = fb_info->drm_format;
 350         gvt_dmabuf->drm_format_mod = fb_info->drm_format_mod;
 351         gvt_dmabuf->width = fb_info->width;
 352         gvt_dmabuf->height = fb_info->height;
 353         gvt_dmabuf->stride = fb_info->stride;
 354         gvt_dmabuf->size = fb_info->size;
 355         gvt_dmabuf->x_pos = fb_info->x_pos;
 356         gvt_dmabuf->y_pos = fb_info->y_pos;
 357         gvt_dmabuf->x_hot = fb_info->x_hot;
 358         gvt_dmabuf->y_hot = fb_info->y_hot;
 359 }
 360 
 361 int intel_vgpu_query_plane(struct intel_vgpu *vgpu, void *args)
 362 {
 363         struct drm_device *dev = &vgpu->gvt->dev_priv->drm;
 364         struct vfio_device_gfx_plane_info *gfx_plane_info = args;
 365         struct intel_vgpu_dmabuf_obj *dmabuf_obj;
 366         struct intel_vgpu_fb_info fb_info;
 367         int ret = 0;
 368 
 369         if (gfx_plane_info->flags == (VFIO_GFX_PLANE_TYPE_DMABUF |
 370                                        VFIO_GFX_PLANE_TYPE_PROBE))
 371                 return ret;
 372         else if ((gfx_plane_info->flags & ~VFIO_GFX_PLANE_TYPE_DMABUF) ||
 373                         (!gfx_plane_info->flags))
 374                 return -EINVAL;
 375 
 376         ret = vgpu_get_plane_info(dev, vgpu, &fb_info,
 377                                         gfx_plane_info->drm_plane_type);
 378         if (ret != 0)
 379                 goto out;
 380 
 381         mutex_lock(&vgpu->dmabuf_lock);
 382         /* If exists, pick up the exposed dmabuf_obj */
 383         dmabuf_obj = pick_dmabuf_by_info(vgpu, &fb_info);
 384         if (dmabuf_obj) {
 385                 update_fb_info(gfx_plane_info, &fb_info);
 386                 gfx_plane_info->dmabuf_id = dmabuf_obj->dmabuf_id;
 387 
 388                 /* This buffer may be released between query_plane ioctl and
 389                  * get_dmabuf ioctl. Add the refcount to make sure it won't
 390                  * be released between the two ioctls.
 391                  */
 392                 if (!dmabuf_obj->initref) {
 393                         dmabuf_obj->initref = true;
 394                         dmabuf_obj_get(dmabuf_obj);
 395                 }
 396                 ret = 0;
 397                 gvt_dbg_dpy("vgpu%d: re-use dmabuf_obj ref %d, id %d\n",
 398                             vgpu->id, kref_read(&dmabuf_obj->kref),
 399                             gfx_plane_info->dmabuf_id);
 400                 mutex_unlock(&vgpu->dmabuf_lock);
 401                 goto out;
 402         }
 403 
 404         mutex_unlock(&vgpu->dmabuf_lock);
 405 
 406         /* Need to allocate a new one*/
 407         dmabuf_obj = kmalloc(sizeof(struct intel_vgpu_dmabuf_obj), GFP_KERNEL);
 408         if (unlikely(!dmabuf_obj)) {
 409                 gvt_vgpu_err("alloc dmabuf_obj failed\n");
 410                 ret = -ENOMEM;
 411                 goto out;
 412         }
 413 
 414         dmabuf_obj->info = kmalloc(sizeof(struct intel_vgpu_fb_info),
 415                                    GFP_KERNEL);
 416         if (unlikely(!dmabuf_obj->info)) {
 417                 gvt_vgpu_err("allocate intel vgpu fb info failed\n");
 418                 ret = -ENOMEM;
 419                 goto out_free_dmabuf;
 420         }
 421         memcpy(dmabuf_obj->info, &fb_info, sizeof(struct intel_vgpu_fb_info));
 422 
 423         ((struct intel_vgpu_fb_info *)dmabuf_obj->info)->obj = dmabuf_obj;
 424 
 425         dmabuf_obj->vgpu = vgpu;
 426 
 427         ret = idr_alloc(&vgpu->object_idr, dmabuf_obj, 1, 0, GFP_NOWAIT);
 428         if (ret < 0)
 429                 goto out_free_info;
 430         gfx_plane_info->dmabuf_id = ret;
 431         dmabuf_obj->dmabuf_id = ret;
 432 
 433         dmabuf_obj->initref = true;
 434 
 435         kref_init(&dmabuf_obj->kref);
 436 
 437         mutex_lock(&vgpu->dmabuf_lock);
 438         if (intel_gvt_hypervisor_get_vfio_device(vgpu)) {
 439                 gvt_vgpu_err("get vfio device failed\n");
 440                 mutex_unlock(&vgpu->dmabuf_lock);
 441                 goto out_free_info;
 442         }
 443         mutex_unlock(&vgpu->dmabuf_lock);
 444 
 445         update_fb_info(gfx_plane_info, &fb_info);
 446 
 447         INIT_LIST_HEAD(&dmabuf_obj->list);
 448         mutex_lock(&vgpu->dmabuf_lock);
 449         list_add_tail(&dmabuf_obj->list, &vgpu->dmabuf_obj_list_head);
 450         mutex_unlock(&vgpu->dmabuf_lock);
 451 
 452         gvt_dbg_dpy("vgpu%d: %s new dmabuf_obj ref %d, id %d\n", vgpu->id,
 453                     __func__, kref_read(&dmabuf_obj->kref), ret);
 454 
 455         return 0;
 456 
 457 out_free_info:
 458         kfree(dmabuf_obj->info);
 459 out_free_dmabuf:
 460         kfree(dmabuf_obj);
 461 out:
 462         /* ENODEV means plane isn't ready, which might be a normal case. */
 463         return (ret == -ENODEV) ? 0 : ret;
 464 }
 465 
 466 /* To associate an exposed dmabuf with the dmabuf_obj */
 467 int intel_vgpu_get_dmabuf(struct intel_vgpu *vgpu, unsigned int dmabuf_id)
 468 {
 469         struct drm_device *dev = &vgpu->gvt->dev_priv->drm;
 470         struct intel_vgpu_dmabuf_obj *dmabuf_obj;
 471         struct drm_i915_gem_object *obj;
 472         struct dma_buf *dmabuf;
 473         int dmabuf_fd;
 474         int ret = 0;
 475 
 476         mutex_lock(&vgpu->dmabuf_lock);
 477 
 478         dmabuf_obj = pick_dmabuf_by_num(vgpu, dmabuf_id);
 479         if (dmabuf_obj == NULL) {
 480                 gvt_vgpu_err("invalid dmabuf id:%d\n", dmabuf_id);
 481                 ret = -EINVAL;
 482                 goto out;
 483         }
 484 
 485         obj = vgpu_create_gem(dev, dmabuf_obj->info);
 486         if (obj == NULL) {
 487                 gvt_vgpu_err("create gvt gem obj failed\n");
 488                 ret = -ENOMEM;
 489                 goto out;
 490         }
 491 
 492         obj->gvt_info = dmabuf_obj->info;
 493 
 494         dmabuf = i915_gem_prime_export(&obj->base, DRM_CLOEXEC | DRM_RDWR);
 495         if (IS_ERR(dmabuf)) {
 496                 gvt_vgpu_err("export dma-buf failed\n");
 497                 ret = PTR_ERR(dmabuf);
 498                 goto out_free_gem;
 499         }
 500 
 501         ret = dma_buf_fd(dmabuf, DRM_CLOEXEC | DRM_RDWR);
 502         if (ret < 0) {
 503                 gvt_vgpu_err("create dma-buf fd failed ret:%d\n", ret);
 504                 goto out_free_dmabuf;
 505         }
 506         dmabuf_fd = ret;
 507 
 508         dmabuf_obj_get(dmabuf_obj);
 509 
 510         if (dmabuf_obj->initref) {
 511                 dmabuf_obj->initref = false;
 512                 dmabuf_obj_put(dmabuf_obj);
 513         }
 514 
 515         mutex_unlock(&vgpu->dmabuf_lock);
 516 
 517         gvt_dbg_dpy("vgpu%d: dmabuf:%d, dmabuf ref %d, fd:%d\n"
 518                     "        file count: %ld, GEM ref: %d\n",
 519                     vgpu->id, dmabuf_obj->dmabuf_id,
 520                     kref_read(&dmabuf_obj->kref),
 521                     dmabuf_fd,
 522                     file_count(dmabuf->file),
 523                     kref_read(&obj->base.refcount));
 524 
 525         i915_gem_object_put(obj);
 526 
 527         return dmabuf_fd;
 528 
 529 out_free_dmabuf:
 530         dma_buf_put(dmabuf);
 531 out_free_gem:
 532         i915_gem_object_put(obj);
 533 out:
 534         mutex_unlock(&vgpu->dmabuf_lock);
 535         return ret;
 536 }
 537 
 538 void intel_vgpu_dmabuf_cleanup(struct intel_vgpu *vgpu)
 539 {
 540         struct list_head *pos, *n;
 541         struct intel_vgpu_dmabuf_obj *dmabuf_obj;
 542 
 543         mutex_lock(&vgpu->dmabuf_lock);
 544         list_for_each_safe(pos, n, &vgpu->dmabuf_obj_list_head) {
 545                 dmabuf_obj = container_of(pos, struct intel_vgpu_dmabuf_obj,
 546                                                 list);
 547                 dmabuf_obj->vgpu = NULL;
 548 
 549                 idr_remove(&vgpu->object_idr, dmabuf_obj->dmabuf_id);
 550                 intel_gvt_hypervisor_put_vfio_device(vgpu);
 551                 list_del(pos);
 552 
 553                 /* dmabuf_obj might be freed in dmabuf_obj_put */
 554                 if (dmabuf_obj->initref) {
 555                         dmabuf_obj->initref = false;
 556                         dmabuf_obj_put(dmabuf_obj);
 557                 }
 558 
 559         }
 560         mutex_unlock(&vgpu->dmabuf_lock);
 561 }