drm/vmwgfx: Use TTM handles instead of SIDs as user-space surface handles.

Improve the command verifier to catch all occurences of surface handles,
and translate to SIDs.

This way DMA buffers and 3D surfaces share a common handle space,
which makes it possible for the kms code to differentiate.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

4 files changed, 209 insertions, 111 deletions

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
index 43546d0..e61bd85 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
@@ -123,6 +123,7 @@ struct vmw_sw_context{
 	uint32_t last_cid;
 	bool cid_valid;
 	uint32_t last_sid;
+	uint32_t sid_translation;
 	bool sid_valid;
 	struct ttm_object_file *tfile;
 	struct list_head validate_nodes;
@@ -317,9 +318,10 @@ extern void vmw_surface_res_free(struct vmw_resource *res);
 extern int vmw_surface_init(struct vmw_private *dev_priv,
 			    struct vmw_surface *srf,
 			    void (*res_free) (struct vmw_resource *res));
-extern int vmw_user_surface_lookup(struct vmw_private *dev_priv,
-				   struct ttm_object_file *tfile,
-				   int sid, struct vmw_surface **out);
+extern int vmw_user_surface_lookup_handle(struct vmw_private *dev_priv,
+					  struct ttm_object_file *tfile,
+					  uint32_t handle,
+					  struct vmw_surface **out);
 extern int vmw_surface_destroy_ioctl(struct drm_device *dev, void *data,
 				     struct drm_file *file_priv);
 extern int vmw_surface_define_ioctl(struct drm_device *dev, void *data,
@@ -328,7 +330,7 @@ extern int vmw_surface_reference_ioctl(struct drm_device *dev, void *data,
 				       struct drm_file *file_priv);
 extern int vmw_surface_check(struct vmw_private *dev_priv,
 			     struct ttm_object_file *tfile,
-			     int id);
+			     uint32_t handle, int *id);
 extern void vmw_dmabuf_bo_free(struct ttm_buffer_object *bo);
 extern int vmw_dmabuf_init(struct vmw_private *dev_priv,
 			   struct vmw_dma_buffer *vmw_bo,
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
index 7e73cf5..2e92da5 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
@@ -73,21 +73,32 @@ static int vmw_cmd_cid_check(struct vmw_private *dev_priv,
 
 static int vmw_cmd_sid_check(struct vmw_private *dev_priv,
 			     struct vmw_sw_context *sw_context,
-			     uint32_t sid)
+			     uint32_t *sid)
 {
-	if (unlikely((!sw_context->sid_valid || sid != sw_context->last_sid) &&
-		     sid != SVGA3D_INVALID_ID)) {
-		int ret = vmw_surface_check(dev_priv, sw_context->tfile, sid);
+	if (*sid == SVGA3D_INVALID_ID)
+		return 0;
+
+	if (unlikely((!sw_context->sid_valid  ||
+		      *sid != sw_context->last_sid))) {
+		int real_id;
+		int ret = vmw_surface_check(dev_priv, sw_context->tfile,
+					    *sid, &real_id);
 
 		if (unlikely(ret != 0)) {
-			DRM_ERROR("Could ot find or use surface %u\n",
-				  (unsigned) sid);
+			DRM_ERROR("Could ot find or use surface 0x%08x "
+				  "address 0x%08lx\n",
+				  (unsigned int) *sid,
+				  (unsigned long) sid);
 			return ret;
 		}
 
-		sw_context->last_sid = sid;
+		sw_context->last_sid = *sid;
 		sw_context->sid_valid = true;
-	}
+		*sid = real_id;
+		sw_context->sid_translation = real_id;
+	} else
+		*sid = sw_context->sid_translation;
+
 	return 0;
 }
 
@@ -107,7 +118,8 @@ static int vmw_cmd_set_render_target_check(struct vmw_private *dev_priv,
 		return ret;
 
 	cmd = container_of(header, struct vmw_sid_cmd, header);
-	return vmw_cmd_sid_check(dev_priv, sw_context, cmd->body.target.sid);
+	ret = vmw_cmd_sid_check(dev_priv, sw_context, &cmd->body.target.sid);
+	return ret;
 }
 
 static int vmw_cmd_surface_copy_check(struct vmw_private *dev_priv,
@@ -121,10 +133,10 @@ static int vmw_cmd_surface_copy_check(struct vmw_private *dev_priv,
 	int ret;
 
 	cmd = container_of(header, struct vmw_sid_cmd, header);
-	ret = vmw_cmd_sid_check(dev_priv, sw_context, cmd->body.src.sid);
+	ret = vmw_cmd_sid_check(dev_priv, sw_context, &cmd->body.src.sid);
 	if (unlikely(ret != 0))
 		return ret;
-	return vmw_cmd_sid_check(dev_priv, sw_context, cmd->body.dest.sid);
+	return vmw_cmd_sid_check(dev_priv, sw_context, &cmd->body.dest.sid);
 }
 
 static int vmw_cmd_stretch_blt_check(struct vmw_private *dev_priv,
@@ -138,10 +150,10 @@ static int vmw_cmd_stretch_blt_check(struct vmw_private *dev_priv,
 	int ret;
 
 	cmd = container_of(header, struct vmw_sid_cmd, header);
-	ret = vmw_cmd_sid_check(dev_priv, sw_context, cmd->body.src.sid);
+	ret = vmw_cmd_sid_check(dev_priv, sw_context, &cmd->body.src.sid);
 	if (unlikely(ret != 0))
 		return ret;
-	return vmw_cmd_sid_check(dev_priv, sw_context, cmd->body.dest.sid);
+	return vmw_cmd_sid_check(dev_priv, sw_context, &cmd->body.dest.sid);
 }
 
 static int vmw_cmd_blt_surf_screen_check(struct vmw_private *dev_priv,
@@ -154,7 +166,7 @@ static int vmw_cmd_blt_surf_screen_check(struct vmw_private *dev_priv,
 	} *cmd;
 
 	cmd = container_of(header, struct vmw_sid_cmd, header);
-	return vmw_cmd_sid_check(dev_priv, sw_context, cmd->body.srcImage.sid);
+	return vmw_cmd_sid_check(dev_priv, sw_context, &cmd->body.srcImage.sid);
 }
 
 static int vmw_cmd_present_check(struct vmw_private *dev_priv,
@@ -167,7 +179,7 @@ static int vmw_cmd_present_check(struct vmw_private *dev_priv,
 	} *cmd;
 
 	cmd = container_of(header, struct vmw_sid_cmd, header);
-	return vmw_cmd_sid_check(dev_priv, sw_context, cmd->body.sid);
+	return vmw_cmd_sid_check(dev_priv, sw_context, &cmd->body.sid);
 }
 
 static int vmw_cmd_dma(struct vmw_private *dev_priv,
@@ -187,12 +199,7 @@ static int vmw_cmd_dma(struct vmw_private *dev_priv,
 	uint32_t cur_validate_node;
 	struct ttm_validate_buffer *val_buf;
 
-
 	cmd = container_of(header, struct vmw_dma_cmd, header);
-	ret = vmw_cmd_sid_check(dev_priv, sw_context, cmd->dma.host.sid);
-	if (unlikely(ret != 0))
-		return ret;
-
 	handle = cmd->dma.guest.ptr.gmrId;
 	ret = vmw_user_dmabuf_lookup(sw_context->tfile, handle, &vmw_bo);
 	if (unlikely(ret != 0)) {
@@ -228,14 +235,23 @@ static int vmw_cmd_dma(struct vmw_private *dev_priv,
 		++sw_context->cur_val_buf;
 	}
 
-	ret = vmw_user_surface_lookup(dev_priv, sw_context->tfile,
-				      cmd->dma.host.sid, &srf);
+	ret = vmw_user_surface_lookup_handle(dev_priv, sw_context->tfile,
+					     cmd->dma.host.sid, &srf);
 	if (ret) {
 		DRM_ERROR("could not find surface\n");
 		goto out_no_reloc;
 	}
 
+	/**
+	 * Patch command stream with device SID.
+	 */
+
+	cmd->dma.host.sid = srf->res.id;
 	vmw_kms_cursor_snoop(srf, sw_context->tfile, bo, header);
+	/**
+	 * FIXME: May deadlock here when called from the
+	 * command parsing code.
+	 */
 	vmw_surface_unreference(&srf);
 
 out_no_reloc:
@@ -243,6 +259,90 @@ out_no_reloc:
 	return ret;
 }
 
+static int vmw_cmd_draw(struct vmw_private *dev_priv,
+			struct vmw_sw_context *sw_context,
+			SVGA3dCmdHeader *header)
+{
+	struct vmw_draw_cmd {
+		SVGA3dCmdHeader header;
+		SVGA3dCmdDrawPrimitives body;
+	} *cmd;
+	SVGA3dVertexDecl *decl = (SVGA3dVertexDecl *)(
+		(unsigned long)header + sizeof(*cmd));
+	SVGA3dPrimitiveRange *range;
+	uint32_t i;
+	uint32_t maxnum;
+	int ret;
+
+	ret = vmw_cmd_cid_check(dev_priv, sw_context, header);
+	if (unlikely(ret != 0))
+		return ret;
+
+	cmd = container_of(header, struct vmw_draw_cmd, header);
+	maxnum = (header->size - sizeof(cmd->body)) / sizeof(*decl);
+
+	if (unlikely(cmd->body.numVertexDecls > maxnum)) {
+		DRM_ERROR("Illegal number of vertex declarations.\n");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < cmd->body.numVertexDecls; ++i, ++decl) {
+		ret = vmw_cmd_sid_check(dev_priv, sw_context,
+					&decl->array.surfaceId);
+		if (unlikely(ret != 0))
+			return ret;
+	}
+
+	maxnum = (header->size - sizeof(cmd->body) -
+		  cmd->body.numVertexDecls * sizeof(*decl)) / sizeof(*range);
+	if (unlikely(cmd->body.numRanges > maxnum)) {
+		DRM_ERROR("Illegal number of index ranges.\n");
+		return -EINVAL;
+	}
+
+	range = (SVGA3dPrimitiveRange *) decl;
+	for (i = 0; i < cmd->body.numRanges; ++i, ++range) {
+		ret = vmw_cmd_sid_check(dev_priv, sw_context,
+					&range->indexArray.surfaceId);
+		if (unlikely(ret != 0))
+			return ret;
+	}
+	return 0;
+}
+
+
+static int vmw_cmd_tex_state(struct vmw_private *dev_priv,
+			     struct vmw_sw_context *sw_context,
+			     SVGA3dCmdHeader *header)
+{
+	struct vmw_tex_state_cmd {
+		SVGA3dCmdHeader header;
+		SVGA3dCmdSetTextureState state;
+	};
+
+	SVGA3dTextureState *last_state = (SVGA3dTextureState *)
+	  ((unsigned long) header + header->size + sizeof(header));
+	SVGA3dTextureState *cur_state = (SVGA3dTextureState *)
+		((unsigned long) header + sizeof(struct vmw_tex_state_cmd));
+	int ret;
+
+	ret = vmw_cmd_cid_check(dev_priv, sw_context, header);
+	if (unlikely(ret != 0))
+		return ret;
+
+	for (; cur_state < last_state; ++cur_state) {
+		if (likely(cur_state->name != SVGA3D_TS_BIND_TEXTURE))
+			continue;
+
+		ret = vmw_cmd_sid_check(dev_priv, sw_context,
+					&cur_state->value);
+		if (unlikely(ret != 0))
+			return ret;
+	}
+
+	return 0;
+}
+
 
 typedef int (*vmw_cmd_func) (struct vmw_private *,
 			     struct vmw_sw_context *,
@@ -264,7 +364,7 @@ static vmw_cmd_func vmw_cmd_funcs[SVGA_3D_CMD_MAX] = {
 	VMW_CMD_DEF(SVGA_3D_CMD_SETRENDERSTATE, &vmw_cmd_cid_check),
 	VMW_CMD_DEF(SVGA_3D_CMD_SETRENDERTARGET,
 		    &vmw_cmd_set_render_target_check),
-	VMW_CMD_DEF(SVGA_3D_CMD_SETTEXTURESTATE, &vmw_cmd_cid_check),
+	VMW_CMD_DEF(SVGA_3D_CMD_SETTEXTURESTATE, &vmw_cmd_tex_state),
 	VMW_CMD_DEF(SVGA_3D_CMD_SETMATERIAL, &vmw_cmd_cid_check),
 	VMW_CMD_DEF(SVGA_3D_CMD_SETLIGHTDATA, &vmw_cmd_cid_check),
 	VMW_CMD_DEF(SVGA_3D_CMD_SETLIGHTENABLED, &vmw_cmd_cid_check),
@@ -276,7 +376,7 @@ static vmw_cmd_func vmw_cmd_funcs[SVGA_3D_CMD_MAX] = {
 	VMW_CMD_DEF(SVGA_3D_CMD_SHADER_DESTROY, &vmw_cmd_cid_check),
 	VMW_CMD_DEF(SVGA_3D_CMD_SET_SHADER, &vmw_cmd_cid_check),
 	VMW_CMD_DEF(SVGA_3D_CMD_SET_SHADER_CONST, &vmw_cmd_cid_check),
-	VMW_CMD_DEF(SVGA_3D_CMD_DRAW_PRIMITIVES, &vmw_cmd_cid_check),
+	VMW_CMD_DEF(SVGA_3D_CMD_DRAW_PRIMITIVES, &vmw_cmd_draw),
 	VMW_CMD_DEF(SVGA_3D_CMD_SETSCISSORRECT, &vmw_cmd_cid_check),
 	VMW_CMD_DEF(SVGA_3D_CMD_BEGIN_QUERY, &vmw_cmd_cid_check),
 	VMW_CMD_DEF(SVGA_3D_CMD_END_QUERY, &vmw_cmd_cid_check),
@@ -291,6 +391,7 @@ static int vmw_cmd_check(struct vmw_private *dev_priv,
 			 void *buf, uint32_t *size)
 {
 	uint32_t cmd_id;
+	uint32_t size_remaining = *size;
 	SVGA3dCmdHeader *header = (SVGA3dCmdHeader *) buf;
 	int ret;
 
@@ -304,6 +405,9 @@ static int vmw_cmd_check(struct vmw_private *dev_priv,
 	*size = le32_to_cpu(header->size) + sizeof(SVGA3dCmdHeader);
 
 	cmd_id -= SVGA_3D_CMD_BASE;
+	if (unlikely(*size > size_remaining))
+		goto out_err;
+
 	if (unlikely(cmd_id >= SVGA_3D_CMD_MAX - SVGA_3D_CMD_BASE))
 		goto out_err;
 
@@ -326,6 +430,7 @@ static int vmw_cmd_check_all(struct vmw_private *dev_priv,
 	int ret;
 
 	while (cur_size > 0) {
+		size = cur_size;
 		ret = vmw_cmd_check(dev_priv, sw_context, buf, &size);
 		if (unlikely(ret != 0))
 			return ret;
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index e9403be..b1af76e 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -106,8 +106,8 @@ int vmw_du_crtc_cursor_set(struct drm_crtc *crtc, struct drm_file *file_priv,
 	int ret;
 
 	if (handle) {
-		ret = vmw_user_surface_lookup(dev_priv, tfile,
-					      handle, &surface);
+		ret = vmw_user_surface_lookup_handle(dev_priv, tfile,
+						     handle, &surface);
 		if (!ret) {
 			if (!surface->snooper.image) {
 				DRM_ERROR("surface not suitable for cursor\n");
@@ -704,8 +704,8 @@ static struct drm_framebuffer *vmw_kms_fb_create(struct drm_device *dev,
 	struct vmw_dma_buffer *bo = NULL;
 	int ret;
 
-	ret = vmw_user_surface_lookup(dev_priv, tfile,
-				      mode_cmd->handle, &surface);
+	ret = vmw_user_surface_lookup_handle(dev_priv, tfile,
+					     mode_cmd->handle, &surface);
 	if (ret)
 		goto try_dmabuf;
 
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c b/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
index a1ceed0..c012d59 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
@@ -488,28 +488,44 @@ static void vmw_user_surface_free(struct vmw_resource *res)
 	kfree(user_srf);
 }
 
-int vmw_user_surface_lookup(struct vmw_private *dev_priv,
-			    struct ttm_object_file *tfile,
-			    int sid, struct vmw_surface **out)
+int vmw_user_surface_lookup_handle(struct vmw_private *dev_priv,
+				   struct ttm_object_file *tfile,
+				   uint32_t handle, struct vmw_surface **out)
 {
 	struct vmw_resource *res;
 	struct vmw_surface *srf;
 	struct vmw_user_surface *user_srf;
+	struct ttm_base_object *base;
+	int ret = -EINVAL;
 
-	res = vmw_resource_lookup(dev_priv, &dev_priv->surface_idr, sid);
-	if (unlikely(res == NULL))
+	base = ttm_base_object_lookup(tfile, handle);
+	if (unlikely(base == NULL))
 		return -EINVAL;
 
-	if (res->res_free != &vmw_user_surface_free)
-		return -EINVAL;
+	if (unlikely(base->object_type != VMW_RES_SURFACE))
+		goto out_bad_resource;
 
-	srf = container_of(res, struct vmw_surface, res);
-	user_srf = container_of(srf, struct vmw_user_surface, srf);
-	if (user_srf->base.tfile != tfile && !user_srf->base.shareable)
-		return -EPERM;
+	user_srf = container_of(base, struct vmw_user_surface, base);
+	srf = &user_srf->srf;
+	res = &srf->res;
+
+	read_lock(&dev_priv->resource_lock);
+
+	if (!res->avail || res->res_free != &vmw_user_surface_free) {
+		read_unlock(&dev_priv->resource_lock);
+		goto out_bad_resource;
+	}
+
+	kref_get(&res->kref);
+	read_unlock(&dev_priv->resource_lock);
 
 	*out = srf;
-	return 0;
+	ret = 0;
+
+out_bad_resource:
+	ttm_base_object_unref(&base);
+
+	return ret;
 }
 
 static void vmw_user_surface_base_release(struct ttm_base_object **p_base)
@@ -526,35 +542,10 @@ static void vmw_user_surface_base_release(struct ttm_base_object **p_base)
 int vmw_surface_destroy_ioctl(struct drm_device *dev, void *data,
 			      struct drm_file *file_priv)
 {
-	struct vmw_private *dev_priv = vmw_priv(dev);
-	struct vmw_resource *res;
-	struct vmw_surface *srf;
-	struct vmw_user_surface *user_srf;
 	struct drm_vmw_surface_arg *arg = (struct drm_vmw_surface_arg *)data;
 	struct ttm_object_file *tfile = vmw_fpriv(file_priv)->tfile;
-	int ret = 0;
-
-	res = vmw_resource_lookup(dev_priv, &dev_priv->surface_idr, arg->sid);
-	if (unlikely(res == NULL))
-		return -EINVAL;
-
-	if (res->res_free != &vmw_user_surface_free) {
-		ret = -EINVAL;
-		goto out;
-	}
 
-	srf = container_of(res, struct vmw_surface, res);
-	user_srf = container_of(srf, struct vmw_user_surface, srf);
-	if (user_srf->base.tfile != tfile && !user_srf->base.shareable) {
-		ret = -EPERM;
-		goto out;
-	}
-
-	ttm_ref_object_base_unref(tfile, user_srf->base.hash.key,
-				  TTM_REF_USAGE);
-out:
-	vmw_resource_unreference(&res);
-	return ret;
+	return ttm_ref_object_base_unref(tfile, arg->sid, TTM_REF_USAGE);
 }
 
 int vmw_surface_define_ioctl(struct drm_device *dev, void *data,
@@ -649,7 +640,10 @@ int vmw_surface_define_ioctl(struct drm_device *dev, void *data,
 	}
 	srf->snooper.crtc = NULL;
 
-	rep->sid = res->id;
+	rep->sid = user_srf->base.hash.key;
+	if (rep->sid == SVGA3D_INVALID_ID)
+		DRM_ERROR("Created bad Surface ID.\n");
+
 	vmw_resource_unreference(&res);
 	return 0;
 out_err1:
@@ -662,39 +656,33 @@ out_err0:
 int vmw_surface_reference_ioctl(struct drm_device *dev, void *data,
 				struct drm_file *file_priv)
 {
-	struct vmw_private *dev_priv = vmw_priv(dev);
 	union drm_vmw_surface_reference_arg *arg =
 	    (union drm_vmw_surface_reference_arg *)data;
 	struct drm_vmw_surface_arg *req = &arg->req;
 	struct drm_vmw_surface_create_req *rep = &arg->rep;
 	struct ttm_object_file *tfile = vmw_fpriv(file_priv)->tfile;
-	struct vmw_resource *res;
 	struct vmw_surface *srf;
 	struct vmw_user_surface *user_srf;
 	struct drm_vmw_size __user *user_sizes;
-	int ret;
+	struct ttm_base_object *base;
+	int ret = -EINVAL;
 
-	res = vmw_resource_lookup(dev_priv, &dev_priv->surface_idr, req->sid);
-	if (unlikely(res == NULL))
+	base = ttm_base_object_lookup(tfile, req->sid);
+	if (unlikely(base == NULL)) {
+		DRM_ERROR("Could not find surface to reference.\n");
 		return -EINVAL;
-
-	if (res->res_free != &vmw_user_surface_free) {
-		ret = -EINVAL;
-		goto out;
 	}
 
-	srf = container_of(res, struct vmw_surface, res);
-	user_srf = container_of(srf, struct vmw_user_surface, srf);
-	if (user_srf->base.tfile != tfile && !user_srf->base.shareable) {
-		DRM_ERROR("Tried to reference none shareable surface\n");
-		ret = -EPERM;
-		goto out;
-	}
+	if (unlikely(base->object_type != VMW_RES_SURFACE))
+		goto out_bad_resource;
+
+	user_srf = container_of(base, struct vmw_user_surface, base);
+	srf = &user_srf->srf;
 
 	ret = ttm_ref_object_add(tfile, &user_srf->base, TTM_REF_USAGE, NULL);
 	if (unlikely(ret != 0)) {
 		DRM_ERROR("Could not add a reference to a surface.\n");
-		goto out;
+		goto out_no_reference;
 	}
 
 	rep->flags = srf->flags;
@@ -706,40 +694,43 @@ int vmw_surface_reference_ioctl(struct drm_device *dev, void *data,
 	if (user_sizes)
 		ret = copy_to_user(user_sizes, srf->sizes,
 				   srf->num_sizes * sizeof(*srf->sizes));
-	if (unlikely(ret != 0)) {
+	if (unlikely(ret != 0))
 		DRM_ERROR("copy_to_user failed %p %u\n",
 			  user_sizes, srf->num_sizes);
-		/**
-		 * FIXME: Unreference surface here?
-		 */
-		goto out;
-	}
-out:
-	vmw_resource_unreference(&res);
+out_bad_resource:
+out_no_reference:
+	ttm_base_object_unref(&base);
+
 	return ret;
 }
 
 int vmw_surface_check(struct vmw_private *dev_priv,
 		      struct ttm_object_file *tfile,
-		      int id)
+		      uint32_t handle, int *id)
 {
-	struct vmw_resource *res;
-	int ret = 0;
+	struct ttm_base_object *base;
+	struct vmw_user_surface *user_srf;
 
-	read_lock(&dev_priv->resource_lock);
-	res = idr_find(&dev_priv->surface_idr, id);
-	if (res && res->avail) {
-		struct vmw_surface *srf =
-			container_of(res, struct vmw_surface, res);
-		struct vmw_user_surface *usrf =
-			container_of(srf, struct vmw_user_surface, srf);
+	int ret = -EPERM;
 
-		if (usrf->base.tfile != tfile && !usrf->base.shareable)
-			ret = -EPERM;
-	} else
-		ret = -EINVAL;
-	read_unlock(&dev_priv->resource_lock);
+	base = ttm_base_object_lookup(tfile, handle);
+	if (unlikely(base == NULL))
+		return -EINVAL;
+
+	if (unlikely(base->object_type != VMW_RES_SURFACE))
+		goto out_bad_surface;
 
+	user_srf = container_of(base, struct vmw_user_surface, base);
+	*id = user_srf->srf.res.id;
+	ret = 0;
+
+out_bad_surface:
+	/**
+	 * FIXME: May deadlock here when called from the
+	 * command parsing code.
+	 */
+
+	ttm_base_object_unref(&base);
 	return ret;
 }