Linux Virtualization - Jun 2019 - [PATCH v3 09/12] drm/virtio: rework virtio_gpu_object_create fencing

Use gem reservation helpers and direct reservation_object_* calls
instead of ttm.

v3: Due to using the gem reservation object it is initialized and ready
for use before calling ttm_bo_init, so we can also drop the tricky fence
logic which checks whenever the command is in flight still.  We can
simply fence our object before submitting the virtio command and be done
with it.

Signed-off-by: Gerd Hoffmann <kraxel at redhat.com>
---
 drivers/gpu/drm/virtio/virtgpu_drv.h    |  6 ++-
 drivers/gpu/drm/virtio/virtgpu_object.c | 54 +++++++++----------------
 drivers/gpu/drm/virtio/virtgpu_vq.c     |  8 +++-
 3 files changed, 30 insertions(+), 38 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h
b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 573173c35c48..834cf7136c78 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -258,7 +258,8 @@ void virtio_gpu_free_vbufs(struct virtio_gpu_device *vgdev);
 void virtio_gpu_cmd_create_resource(struct virtio_gpu_device *vgdev,
 				    struct virtio_gpu_object *bo,
 				    struct virtio_gpu_object_params *params,
-				    struct virtio_gpu_fence *fence);
+				    struct virtio_gpu_fence *fence,
+				    struct drm_gem_object_array *objs);
 void virtio_gpu_cmd_unref_resource(struct virtio_gpu_device *vgdev,
 				   uint32_t resource_id);
 void virtio_gpu_cmd_transfer_to_host_2d(struct virtio_gpu_device *vgdev,
@@ -319,7 +320,8 @@ void
 virtio_gpu_cmd_resource_create_3d(struct virtio_gpu_device *vgdev,
 				  struct virtio_gpu_object *bo,
 				  struct virtio_gpu_object_params *params,
-				  struct virtio_gpu_fence *fence);
+				  struct virtio_gpu_fence *fence,
+				  struct drm_gem_object_array *objs);
 void virtio_gpu_ctrl_ack(struct virtqueue *vq);
 void virtio_gpu_cursor_ack(struct virtqueue *vq);
 void virtio_gpu_fence_ack(struct virtqueue *vq);
diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c
b/drivers/gpu/drm/virtio/virtgpu_object.c
index 82bfbf983fd2..ce33ffa45076 100644
--- a/drivers/gpu/drm/virtio/virtgpu_object.c
+++ b/drivers/gpu/drm/virtio/virtgpu_object.c
@@ -98,6 +98,7 @@ int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
 			     struct virtio_gpu_fence *fence)
 {
 	struct virtio_gpu_object *bo;
+	struct drm_gem_object_array *objs = NULL;
 	size_t acc_size;
 	int ret;
 
@@ -123,10 +124,27 @@ int virtio_gpu_object_create(struct virtio_gpu_device
*vgdev,
 	}
 	bo->dumb = params->dumb;
 
+	if (fence) {
+		struct ww_acquire_ctx ticket;
+
+		objs = drm_gem_array_alloc(1);
+		objs->objs[0] = &bo->gem_base;
+		drm_gem_object_get(objs->objs[0]);
+
+		ret = drm_gem_lock_reservations(objs->objs, objs->nents,
+						&ticket);
+		if (ret == 0)
+			reservation_object_add_excl_fence(objs->objs[0]->resv,
+							  &fence->f);
+		drm_gem_unlock_reservations(objs->objs, objs->nents, &ticket);
+	}
+
 	if (params->virgl) {
-		virtio_gpu_cmd_resource_create_3d(vgdev, bo, params, fence);
+		virtio_gpu_cmd_resource_create_3d(vgdev, bo, params,
+						  fence, objs);
 	} else {
-		virtio_gpu_cmd_create_resource(vgdev, bo, params, fence);
+		virtio_gpu_cmd_create_resource(vgdev, bo, params,
+					       fence, objs);
 	}
 
 	virtio_gpu_init_ttm_placement(bo);
@@ -139,38 +157,6 @@ int virtio_gpu_object_create(struct virtio_gpu_device
*vgdev,
 	if (ret != 0)
 		return ret;
 
-	if (fence) {
-		struct virtio_gpu_fence_driver *drv = &vgdev->fence_drv;
-		struct list_head validate_list;
-		struct ttm_validate_buffer mainbuf;
-		struct ww_acquire_ctx ticket;
-		unsigned long irq_flags;
-		bool signaled;
-
-		INIT_LIST_HEAD(&validate_list);
-		memset(&mainbuf, 0, sizeof(struct ttm_validate_buffer));
-
-		/* use a gem reference since unref list undoes them */
-		drm_gem_object_get(&bo->gem_base);
-		mainbuf.bo = &bo->tbo;
-		list_add(&mainbuf.head, &validate_list);
-
-		ret = virtio_gpu_object_list_validate(&ticket, &validate_list);
-		if (ret == 0) {
-			spin_lock_irqsave(&drv->lock, irq_flags);
-			signaled = virtio_fence_signaled(&fence->f);
-			if (!signaled)
-				/* virtio create command still in flight */
-				ttm_eu_fence_buffer_objects(&ticket, &validate_list,
-							    &fence->f);
-			spin_unlock_irqrestore(&drv->lock, irq_flags);
-			if (signaled)
-				/* virtio create command finished */
-				ttm_eu_backoff_reservation(&ticket, &validate_list);
-		}
-		virtio_gpu_unref_list(&validate_list);
-	}
-
 	*bo_ptr = bo;
 	return 0;
 }
diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c
b/drivers/gpu/drm/virtio/virtgpu_vq.c
index 6efea4fca012..f0609b07f859 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -391,13 +391,15 @@ static int virtio_gpu_queue_cursor(struct
virtio_gpu_device *vgdev,
 void virtio_gpu_cmd_create_resource(struct virtio_gpu_device *vgdev,
 				    struct virtio_gpu_object *bo,
 				    struct virtio_gpu_object_params *params,
-				    struct virtio_gpu_fence *fence)
+				    struct virtio_gpu_fence *fence,
+				    struct drm_gem_object_array *objs)
 {
 	struct virtio_gpu_resource_create_2d *cmd_p;
 	struct virtio_gpu_vbuffer *vbuf;
 
 	cmd_p = virtio_gpu_alloc_cmd(vgdev, &vbuf, sizeof(*cmd_p));
 	memset(cmd_p, 0, sizeof(*cmd_p));
+	vbuf->objs = objs;
 
 	cmd_p->hdr.type = cpu_to_le32(VIRTIO_GPU_CMD_RESOURCE_CREATE_2D);
 	cmd_p->resource_id = cpu_to_le32(bo->hw_res_handle);
@@ -864,13 +866,15 @@ void
 virtio_gpu_cmd_resource_create_3d(struct virtio_gpu_device *vgdev,
 				  struct virtio_gpu_object *bo,
 				  struct virtio_gpu_object_params *params,
-				  struct virtio_gpu_fence *fence)
+				  struct virtio_gpu_fence *fence,
+				  struct drm_gem_object_array *objs)
 {
 	struct virtio_gpu_resource_create_3d *cmd_p;
 	struct virtio_gpu_vbuffer *vbuf;
 
 	cmd_p = virtio_gpu_alloc_cmd(vgdev, &vbuf, sizeof(*cmd_p));
 	memset(cmd_p, 0, sizeof(*cmd_p));
+	vbuf->objs = objs;
 
 	cmd_p->hdr.type = cpu_to_le32(VIRTIO_GPU_CMD_RESOURCE_CREATE_3D);
 	cmd_p->resource_id = cpu_to_le32(bo->hw_res_handle);
-- 
2.18.1