drm/virtio: Ensure framebuffers for dGPU residing in local memory

Leverage the new fields in dmabuf attachment to obtained information about the imported buffers. In atomic check, we must return an error when the user space is trying to present a framebuffer in system memory (without DMABUF_ATTACH_FLAG_LMEM being set) on discrete GPU backing display. Tracked-On: OAM-129610 Signed-off-by: Weifeng Liu <[email protected]>
projectceladon · Feb 24, 2025 · 2a826f4 · 2a826f4
1 parent 5f92a9e
commit 2a826f4
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Showing 3 changed files with 26 additions and 3 deletions.
diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
@@ -23,6 +23,7 @@
  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
+#include <linux/dma-buf.h>
 #include <linux/dma-mapping.h>
 #include <linux/moduleparam.h>
 

diff --git a/drivers/gpu/drm/virtio/virtgpu_plane.c b/drivers/gpu/drm/virtio/virtgpu_plane.c
@@ -23,6 +23,8 @@
  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
+#include <linux/dma-buf.h>
+
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_damage_helper.h>
 #include <drm/drm_fourcc.h>
@@ -264,6 +266,26 @@ static int virtio_gpu_plane_atomic_check(struct drm_plane *plane,
 	if (IS_ERR(crtc_state))
                 return PTR_ERR(crtc_state);
 
+	/* Ensure lmem objects from i915_ag are attached to dGPU backing CRTC */
+	if (vgdev->output_cap_mask & (1lu << drm_crtc_index(new_plane_state->crtc))) {
+		for (int i = 0; i < DRM_FORMAT_MAX_PLANES; ++i) {
+			struct drm_gem_object *obj = new_plane_state->fb->obj[i];
+			if (!obj)
+				break;
+
+			if (!obj->import_attach)
+				return -EINVAL;
+
+			if (!(obj->import_attach->flags & DMABUF_ATTACH_FLAG_LMEM)) {
+				drm_dbg(vgdev->ddev, "cannot use non-i915_ag "
+					"buffer for crtc %u, driver name %s\n",
+					drm_crtc_index(new_plane_state->crtc),
+					obj->dev->driver->name);
+				return -EINVAL;
+			}
+		}
+	}
+
 	if(vgdev->has_scaling && (new_plane_state->fb->format->format != DRM_FORMAT_C8)) {
 		min_scale = 1;
 		max_scale = 0x30000-1;
@@ -322,7 +344,6 @@ static void virtio_gpu_resource_flush(struct drm_plane *plane,
 	struct virtio_gpu_object *bo;
 	struct virtio_gpu_object_array *objs = NULL;
 	struct virtio_gpu_fence *fence = NULL;
-	int i;
 
 	vgfb = to_virtio_gpu_framebuffer(plane->state->fb);
 	bo = gem_to_virtio_gpu_obj(vgfb->base.obj[0]);

diff --git a/drivers/gpu/drm/virtio/virtgpu_prime.c b/drivers/gpu/drm/virtio/virtgpu_prime.c
@@ -180,8 +180,9 @@ struct drm_gem_object *virtgpu_gem_prime_import(struct drm_device *dev,
 	}
 	spin_unlock(&dma_buf->name_lock);
 
-	attach = ____dma_buf_dynamic_attach(dma_buf, attach_dev, NULL, NULL,
-					    p2p);
+	attach = ____dma_buf_dynamic_attach(dma_buf, attach_dev,
+					    DMA_BUF_DRIVER_TYPE_ID_VIRTIO_GPU,
+					    0, NULL, NULL, p2p);
 	if (IS_ERR(attach))
 		return ERR_CAST(attach);