Re: [PATCH v2] drm/vmwgfx: Fix gem refcounting and memory evictions

From: Martin Krastev krastevm@vmware.com

From: Zack Rusin zack@kde.org Date: Wed, 20 Apr 2022 at 07:03 Subject: [PATCH v2] drm/vmwgfx: Fix gem refcounting and memory evictions To: dri-devel@lists.freedesktop.org Cc: krastevm@vmware.com, mombasawalam@vmware.com

From: Zack Rusin zackr@vmware.com

v2: Add the last part of the ref count fix which was spotted by Philipp Sieweck where the ref count of cpu writers is off due to ERESTARTSYS or EBUSY during bo waits.

The initial GEM port broke refcounting on shareable (prime) surfaces and memory evictions. The prime surfaces broke because the parent surfaces weren't increasing the ref count on GEM surfaces, which meant that the memory backing textures could have been deleted while the texture was still accessible. The evictions broke due to a typo, the code was supposed to exit if the passed buffers were not vmw_buffer_object not if they were. They're tied because the evictions depend on having memory to actually evict.

This fixes crashes with XA state tracker which is used for xrender acceleration on xf86-video-vmware, apps/tests which use a lot of memory (a good test being the piglit's streaming-texture-leak) and desktops.

Signed-off-by: Zack Rusin zackr@vmware.com Fixes: 8afa13a0583f ("drm/vmwgfx: Implement DRIVER_GEM") Reported-by: Philipp Sieweck psi@informatik.uni-kiel.de Cc: stable@vger.kernel.org # v5.17+ Reviewed-by: Maaz Mombasawala mombasawalam@vmware.com

---

drivers/gpu/drm/vmwgfx/vmwgfx_bo.c | 43 ++++++++++++------------- drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 8 ++--- drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 7 +++- 3 files changed, 28 insertions(+), 30 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c index 31aecc46624b..04c8a378aeed 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c @@ -46,6 +46,21 @@ vmw_buffer_object(struct ttm_buffer_object *bo) return container_of(bo, struct vmw_buffer_object, base); }

+/**

• • bo_is_vmw - check if the buffer object is a &vmw_buffer_object
• • @bo: ttm buffer object to be checked
• • Uses destroy function associated with the object to determine if this is
• • a &vmw_buffer_object.
• • Returns:
• • true if the object is of &vmw_buffer_object type, false if not.
• */

+static bool bo_is_vmw(struct ttm_buffer_object *bo) +{

•   return bo->destroy == &vmw_bo_bo_free ||
  

•          bo->destroy == &vmw_gem_destroy;
  

+}

/**

• vmw_bo_pin_in_placement - Validate a buffer to placement.

@@ -615,8 +630,9 @@ int vmw_user_bo_synccpu_ioctl(struct drm_device *dev, void *data,

             ret = vmw_user_bo_synccpu_grab(vbo, arg->flags);
             vmw_bo_unreference(&vbo);

•           if (unlikely(ret != 0 && ret != -ERESTARTSYS &&
  

•                        ret != -EBUSY)) {
  

•           if (unlikely(ret != 0)) {
  

•                   if (ret == -ERESTARTSYS || ret == -EBUSY)
  

•                           return -EBUSY;
                     DRM_ERROR("Failed synccpu grab on handle 0x%08x.\n",
                               (unsigned int) arg->handle);
                     return ret;
  

@@ -798,7 +814,7 @@ int vmw_dumb_create(struct drm_file *file_priv, void vmw_bo_swap_notify(struct ttm_buffer_object *bo) { /* Is @bo embedded in a struct vmw_buffer_object? */

•   if (vmw_bo_is_vmw_bo(bo))
  

•   if (!bo_is_vmw(bo))
             return;
  
     /* Kill any cached kernel maps before swapout */
  

@@ -822,7 +838,7 @@ void vmw_bo_move_notify(struct ttm_buffer_object *bo, struct vmw_buffer_object *vbo;

     /* Make sure @bo is embedded in a struct vmw_buffer_object? */

•   if (vmw_bo_is_vmw_bo(bo))
  

•   if (!bo_is_vmw(bo))
             return;
  
     vbo = container_of(bo, struct vmw_buffer_object, base);
  

@@ -843,22 +859,3 @@ void vmw_bo_move_notify(struct ttm_buffer_object *bo, if (mem->mem_type != VMW_PL_MOB && bo->resource->mem_type == VMW_PL_MOB) vmw_resource_unbind_list(vbo); }

-/**

• • vmw_bo_is_vmw_bo - check if the buffer object is a &vmw_buffer_object
• • @bo: buffer object to be checked
• • Uses destroy function associated with the object to determine if this is
• • a &vmw_buffer_object.
• • Returns:
• • true if the object is of &vmw_buffer_object type, false if not.
• */

-bool vmw_bo_is_vmw_bo(struct ttm_buffer_object *bo) -{

•   if (bo->destroy == &vmw_bo_bo_free ||
  

•       bo->destroy == &vmw_gem_destroy)
  

•           return true;
  

•   return false;
  

-} diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c index 72a17618ba0a..0c12faa4e533 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c @@ -1018,13 +1018,10 @@ static int vmw_driver_load(struct vmw_private *dev_priv, u32 pci_id) goto out_no_fman; }

•   drm_vma_offset_manager_init(&dev_priv->vma_manager,
  

•                               DRM_FILE_PAGE_OFFSET_START,
  

•                               DRM_FILE_PAGE_OFFSET_SIZE);
     ret = ttm_device_init(&dev_priv->bdev, &vmw_bo_driver,
                           dev_priv->drm.dev,
                           dev_priv->drm.anon_inode->i_mapping,
  

•                         &dev_priv->vma_manager,
  

•                         dev_priv->drm.vma_offset_manager,
                           dev_priv->map_mode == vmw_dma_alloc_coherent,
                           false);
     if (unlikely(ret != 0)) {
  

@@ -1195,7 +1192,6 @@ static void vmw_driver_unload(struct drm_device *dev) vmw_devcaps_destroy(dev_priv); vmw_vram_manager_fini(dev_priv); ttm_device_fini(&dev_priv->bdev);

•   drm_vma_offset_manager_destroy(&dev_priv->vma_manager);
     vmw_release_device_late(dev_priv);
     vmw_fence_manager_takedown(dev_priv->fman);
     if (dev_priv->capabilities & SVGA_CAP_IRQMASK)
  

@@ -1419,7 +1415,7 @@ vmw_get_unmapped_area(struct file *file, unsigned long uaddr, struct vmw_private *dev_priv = vmw_priv(file_priv->minor->dev);

     return drm_get_unmapped_area(file, uaddr, len, pgoff, flags,

•                                &dev_priv->vma_manager);
  

•                                dev_priv->drm.vma_offset_manager);
  

  }

  static int vmwgfx_pm_notifier(struct notifier_block *nb, unsigned long val,

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c index 00e8e27e4884..ace7ca150b03 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c @@ -683,6 +683,9 @@ static void vmw_user_surface_base_release(struct ttm_base_object **p_base) container_of(base, struct vmw_user_surface, prime.base); struct vmw_resource *res = &user_srf->srf.res;

•   if (base->shareable && res && res->backup)
  

•           drm_gem_object_put(&res->backup->base.base);
  

•    *p_base = NULL;
     vmw_resource_unreference(&res);
  

  }

@@ -857,6 +860,7 @@ int vmw_surface_define_ioctl(struct drm_device *dev, void *data, goto out_unlock; } vmw_bo_reference(res->backup);

•           drm_gem_object_get(&res->backup->base.base);
     }
  
     tmp = vmw_resource_reference(&srf->res);
  

@@ -1513,7 +1517,6 @@ vmw_gb_surface_define_internal(struct drm_device *dev, &res->backup); if (ret == 0) vmw_bo_reference(res->backup);

•    }
  
     if (unlikely(ret != 0)) {
  

@@ -1561,6 +1564,8 @@ vmw_gb_surface_define_internal(struct drm_device *dev,

drm_vma_node_offset_addr(&res->backup->base.base.vma_node); rep->buffer_size = res->backup->base.base.size; rep->buffer_handle = backup_handle;

•           if (user_srf->prime.base.shareable)
  

•                   drm_gem_object_get(&res->backup->base.base);
     } else {
             rep->buffer_map_handle = 0;
             rep->buffer_size = 0;
  

-- 2.32.0

LGTM!

Reviewed-by: Martin Krastev krastevm@vmware.com

Regards,

Martin