[PATCH 1/4] drm/virtio: simplify virtio_gpu_alloc_cmd

[PATCH 1/4] drm/virtio: simplify virtio_gpu_alloc_cmd

[Gerd Hoffmann]

Just call virtio_gpu_alloc_cmd_resp with some fixed args
instead of duplicating most of the function body.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 drivers/gpu/drm/virtio/virtgpu_vq.c | 25 ++++++++-----------------
 1 file changed, 8 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index 5914e79d3429..6d6d55dc384e 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -109,23 +109,6 @@ virtio_gpu_get_vbuf(struct virtio_gpu_device *vgdev,
 	return vbuf;
 }
 
-static void *virtio_gpu_alloc_cmd(struct virtio_gpu_device *vgdev,
-				  struct virtio_gpu_vbuffer **vbuffer_p,
-				  int size)
-{
-	struct virtio_gpu_vbuffer *vbuf;
-
-	vbuf = virtio_gpu_get_vbuf(vgdev, size,
-				   sizeof(struct virtio_gpu_ctrl_hdr),
-				   NULL, NULL);
-	if (IS_ERR(vbuf)) {
-		*vbuffer_p = NULL;
-		return ERR_CAST(vbuf);
-	}
-	*vbuffer_p = vbuf;
-	return vbuf->buf;
-}
-
 static struct virtio_gpu_update_cursor*
 virtio_gpu_alloc_cursor(struct virtio_gpu_device *vgdev,
 			struct virtio_gpu_vbuffer **vbuffer_p)
@@ -161,6 +144,14 @@ static void *virtio_gpu_alloc_cmd_resp(struct virtio_gpu_device *vgdev,
 	return (struct virtio_gpu_command *)vbuf->buf;
 }
 
+static void *virtio_gpu_alloc_cmd(struct virtio_gpu_device *vgdev,
+				  struct virtio_gpu_vbuffer **vbuffer_p,
+				  int size)
+{
+	return virtio_gpu_alloc_cmd_resp(vgdev, NULL, vbuffer_p, size,
+					 sizeof(struct virtio_gpu_ctrl_hdr), NULL);
+}
+
 static void free_vbuf(struct virtio_gpu_device *vgdev,
 		      struct virtio_gpu_vbuffer *vbuf)
 {
-- 
2.18.1

[PATCH 2/4] drm/virtio: resource teardown tweaks

[Gerd Hoffmann]

Add new virtio_gpu_cleanup_object() helper function for object cleanup.
Wire up callback function for resource unref, do cleanup from callback
when we know the host stopped using the resource.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 drivers/gpu/drm/virtio/virtgpu_drv.h    |  3 ++-
 drivers/gpu/drm/virtio/virtgpu_object.c | 19 ++++++++++----
 drivers/gpu/drm/virtio/virtgpu_vq.c     | 35 ++++++++++++++++++++++---
 3 files changed, 48 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 7e69c06e168e..372dd248cf02 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -262,7 +262,7 @@ void virtio_gpu_cmd_create_resource(struct virtio_gpu_device *vgdev,
 				    struct virtio_gpu_object_array *objs,
 				    struct virtio_gpu_fence *fence);
 void virtio_gpu_cmd_unref_resource(struct virtio_gpu_device *vgdev,
-				   uint32_t resource_id);
+				   struct virtio_gpu_object *bo);
 void virtio_gpu_cmd_transfer_to_host_2d(struct virtio_gpu_device *vgdev,
 					uint64_t offset,
 					uint32_t width, uint32_t height,
@@ -355,6 +355,7 @@ void virtio_gpu_fence_event_process(struct virtio_gpu_device *vdev,
 				    u64 last_seq);
 
 /* virtio_gpu_object */
+void virtio_gpu_cleanup_object(struct virtio_gpu_object *bo);
 struct drm_gem_object *virtio_gpu_create_object(struct drm_device *dev,
 						size_t size);
 int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
index 017a9e0fc3bb..28a161af7503 100644
--- a/drivers/gpu/drm/virtio/virtgpu_object.c
+++ b/drivers/gpu/drm/virtio/virtgpu_object.c
@@ -61,6 +61,14 @@ static void virtio_gpu_resource_id_put(struct virtio_gpu_device *vgdev, uint32_t
 	}
 }
 
+void virtio_gpu_cleanup_object(struct virtio_gpu_object *bo)
+{
+	struct virtio_gpu_device *vgdev = bo->base.base.dev->dev_private;
+
+	virtio_gpu_resource_id_put(vgdev, bo->hw_res_handle);
+	drm_gem_shmem_free_object(&bo->base.base);
+}
+
 static void virtio_gpu_free_object(struct drm_gem_object *obj)
 {
 	struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj);
@@ -68,11 +76,12 @@ static void virtio_gpu_free_object(struct drm_gem_object *obj)
 
 	if (bo->pages)
 		virtio_gpu_object_detach(vgdev, bo);
-	if (bo->created)
-		virtio_gpu_cmd_unref_resource(vgdev, bo->hw_res_handle);
-	virtio_gpu_resource_id_put(vgdev, bo->hw_res_handle);
-
-	drm_gem_shmem_free_object(obj);
+	if (bo->created) {
+		virtio_gpu_cmd_unref_resource(vgdev, bo);
+		/* completion handler calls virtio_gpu_cleanup_object() */
+		return;
+	}
+	virtio_gpu_cleanup_object(bo);
 }
 
 static const struct drm_gem_object_funcs virtio_gpu_gem_funcs = {
diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index 6d6d55dc384e..6e8097e4c214 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -152,6 +152,15 @@ static void *virtio_gpu_alloc_cmd(struct virtio_gpu_device *vgdev,
 					 sizeof(struct virtio_gpu_ctrl_hdr), NULL);
 }
 
+static void *virtio_gpu_alloc_cmd_cb(struct virtio_gpu_device *vgdev,
+				     struct virtio_gpu_vbuffer **vbuffer_p,
+				     int size,
+				     virtio_gpu_resp_cb cb)
+{
+	return virtio_gpu_alloc_cmd_resp(vgdev, cb, vbuffer_p, size,
+					 sizeof(struct virtio_gpu_ctrl_hdr), NULL);
+}
+
 static void free_vbuf(struct virtio_gpu_device *vgdev,
 		      struct virtio_gpu_vbuffer *vbuf)
 {
@@ -494,17 +503,37 @@ void virtio_gpu_cmd_create_resource(struct virtio_gpu_device *vgdev,
 	bo->created = true;
 }
 
+static void virtio_gpu_cmd_unref_cb(struct virtio_gpu_device *vgdev,
+				    struct virtio_gpu_vbuffer *vbuf)
+{
+	struct virtio_gpu_object *bo;
+
+	bo = gem_to_virtio_gpu_obj(vbuf->objs->objs[0]);
+	kfree(vbuf->objs);
+	vbuf->objs = NULL;
+
+	virtio_gpu_cleanup_object(bo);
+}
+
 void virtio_gpu_cmd_unref_resource(struct virtio_gpu_device *vgdev,
-				   uint32_t resource_id)
+				   struct virtio_gpu_object *bo)
 {
 	struct virtio_gpu_resource_unref *cmd_p;
 	struct virtio_gpu_vbuffer *vbuf;
 
-	cmd_p = virtio_gpu_alloc_cmd(vgdev, &vbuf, sizeof(*cmd_p));
+	cmd_p = virtio_gpu_alloc_cmd_cb(vgdev, &vbuf, sizeof(*cmd_p),
+					virtio_gpu_cmd_unref_cb);
 	memset(cmd_p, 0, sizeof(*cmd_p));
 
 	cmd_p->hdr.type = cpu_to_le32(VIRTIO_GPU_CMD_RESOURCE_UNREF);
-	cmd_p->resource_id = cpu_to_le32(resource_id);
+	cmd_p->resource_id = cpu_to_le32(bo->hw_res_handle);
+
+	/*
+	 * We are in the release callback and do NOT want refcount
+	 * bo, so do NOT use virtio_gpu_array_add_obj().
+	 */
+	vbuf->objs = virtio_gpu_array_alloc(1);
+	vbuf->objs->objs[0] = &bo->base.base;
 
 	virtio_gpu_queue_ctrl_buffer(vgdev, vbuf);
 }
-- 
2.18.1

[PATCH 3/4] drm/virtio: move mapping teardown to virtio_gpu_cleanup_object()

[Gerd Hoffmann]

Stop sending DETACH_BACKING commands, that will happening anyway when
releasing resources via UNREF.  Handle guest-side cleanup in
virtio_gpu_cleanup_object(), called when the host finished processing
the UNREF command.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 drivers/gpu/drm/virtio/virtgpu_drv.h    |  2 --
 drivers/gpu/drm/virtio/virtgpu_object.c | 14 ++++++--
 drivers/gpu/drm/virtio/virtgpu_vq.c     | 46 -------------------------
 3 files changed, 12 insertions(+), 50 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 372dd248cf02..15fb3c12f22f 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -280,8 +280,6 @@ void virtio_gpu_cmd_set_scanout(struct virtio_gpu_device *vgdev,
 int virtio_gpu_object_attach(struct virtio_gpu_device *vgdev,
 			     struct virtio_gpu_object *obj,
 			     struct virtio_gpu_fence *fence);
-void virtio_gpu_object_detach(struct virtio_gpu_device *vgdev,
-			      struct virtio_gpu_object *obj);
 int virtio_gpu_attach_status_page(struct virtio_gpu_device *vgdev);
 int virtio_gpu_detach_status_page(struct virtio_gpu_device *vgdev);
 void virtio_gpu_cursor_ping(struct virtio_gpu_device *vgdev,
diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
index 28a161af7503..bce2b3d843fe 100644
--- 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-mapping.h>
 #include <linux/moduleparam.h>
 
 #include "virtgpu_drv.h"
@@ -65,6 +66,17 @@ void virtio_gpu_cleanup_object(struct virtio_gpu_object *bo)
 {
 	struct virtio_gpu_device *vgdev = bo->base.base.dev->dev_private;
 
+	if (bo->pages) {
+		if (bo->mapped) {
+			dma_unmap_sg(vgdev->vdev->dev.parent,
+				     bo->pages->sgl, bo->mapped,
+				     DMA_TO_DEVICE);
+			bo->mapped = 0;
+		}
+		sg_free_table(bo->pages);
+		bo->pages = NULL;
+		drm_gem_shmem_unpin(&bo->base.base);
+	}
 	virtio_gpu_resource_id_put(vgdev, bo->hw_res_handle);
 	drm_gem_shmem_free_object(&bo->base.base);
 }
@@ -74,8 +86,6 @@ static void virtio_gpu_free_object(struct drm_gem_object *obj)
 	struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj);
 	struct virtio_gpu_device *vgdev = bo->base.base.dev->dev_private;
 
-	if (bo->pages)
-		virtio_gpu_object_detach(vgdev, bo);
 	if (bo->created) {
 		virtio_gpu_cmd_unref_resource(vgdev, bo);
 		/* completion handler calls virtio_gpu_cleanup_object() */
diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index 6e8097e4c214..e258186bedb2 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -538,22 +538,6 @@ void virtio_gpu_cmd_unref_resource(struct virtio_gpu_device *vgdev,
 	virtio_gpu_queue_ctrl_buffer(vgdev, vbuf);
 }
 
-static void virtio_gpu_cmd_resource_inval_backing(struct virtio_gpu_device *vgdev,
-						  uint32_t resource_id,
-						  struct virtio_gpu_fence *fence)
-{
-	struct virtio_gpu_resource_detach_backing *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));
-
-	cmd_p->hdr.type = cpu_to_le32(VIRTIO_GPU_CMD_RESOURCE_DETACH_BACKING);
-	cmd_p->resource_id = cpu_to_le32(resource_id);
-
-	virtio_gpu_queue_fenced_ctrl_buffer(vgdev, vbuf, &cmd_p->hdr, fence);
-}
-
 void virtio_gpu_cmd_set_scanout(struct virtio_gpu_device *vgdev,
 				uint32_t scanout_id, uint32_t resource_id,
 				uint32_t width, uint32_t height,
@@ -1148,36 +1132,6 @@ int virtio_gpu_object_attach(struct virtio_gpu_device *vgdev,
 	return 0;
 }
 
-void virtio_gpu_object_detach(struct virtio_gpu_device *vgdev,
-			      struct virtio_gpu_object *obj)
-{
-	bool use_dma_api = !virtio_has_iommu_quirk(vgdev->vdev);
-
-	if (WARN_ON_ONCE(!obj->pages))
-		return;
-
-	if (use_dma_api && obj->mapped) {
-		struct virtio_gpu_fence *fence = virtio_gpu_fence_alloc(vgdev);
-		/* detach backing and wait for the host process it ... */
-		virtio_gpu_cmd_resource_inval_backing(vgdev, obj->hw_res_handle, fence);
-		dma_fence_wait(&fence->f, true);
-		dma_fence_put(&fence->f);
-
-		/* ... then tear down iommu mappings */
-		dma_unmap_sg(vgdev->vdev->dev.parent,
-			     obj->pages->sgl, obj->mapped,
-			     DMA_TO_DEVICE);
-		obj->mapped = 0;
-	} else {
-		virtio_gpu_cmd_resource_inval_backing(vgdev, obj->hw_res_handle, NULL);
-	}
-
-	sg_free_table(obj->pages);
-	obj->pages = NULL;
-
-	drm_gem_shmem_unpin(&obj->base.base);
-}
-
 void virtio_gpu_cursor_ping(struct virtio_gpu_device *vgdev,
 			    struct virtio_gpu_output *output)
 {
-- 
2.18.1

[PATCH 4/4] drm/virtio: move virtio_gpu_mem_entry initialization to new function

[Gerd Hoffmann]

Introduce new virtio_gpu_object_shmem_init() helper function which will
create the virtio_gpu_mem_entry array, containing the backing storage
information for the host.  For the most path this just moves code from
virtio_gpu_object_attach().

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 drivers/gpu/drm/virtio/virtgpu_drv.h    |  4 ++
 drivers/gpu/drm/virtio/virtgpu_object.c | 49 +++++++++++++++++++++++++
 drivers/gpu/drm/virtio/virtgpu_vq.c     | 49 ++-----------------------
 3 files changed, 56 insertions(+), 46 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 15fb3c12f22f..be62a7469b04 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -71,6 +71,10 @@ struct virtio_gpu_object {
 
 	struct sg_table *pages;
 	uint32_t mapped;
+
+	struct virtio_gpu_mem_entry *ents;
+	unsigned int nents;
+
 	bool dumb;
 	bool created;
 };
diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
index bce2b3d843fe..4e82e269a1f4 100644
--- a/drivers/gpu/drm/virtio/virtgpu_object.c
+++ b/drivers/gpu/drm/virtio/virtgpu_object.c
@@ -121,6 +121,49 @@ struct drm_gem_object *virtio_gpu_create_object(struct drm_device *dev,
 	return &bo->base.base;
 }
 
+static int virtio_gpu_object_shmem_init(struct virtio_gpu_device *vgdev,
+					struct virtio_gpu_object *bo)
+{
+	bool use_dma_api = !virtio_has_iommu_quirk(vgdev->vdev);
+	struct scatterlist *sg;
+	int si, ret;
+
+	ret = drm_gem_shmem_pin(&bo->base.base);
+	if (ret < 0)
+		return -EINVAL;
+
+	bo->pages = drm_gem_shmem_get_sg_table(&bo->base.base);
+	if (bo->pages == NULL) {
+		drm_gem_shmem_unpin(&bo->base.base);
+		return -EINVAL;
+	}
+
+	if (use_dma_api) {
+		bo->mapped = dma_map_sg(vgdev->vdev->dev.parent,
+					 bo->pages->sgl, bo->pages->nents,
+					 DMA_TO_DEVICE);
+		bo->nents = bo->mapped;
+	} else {
+		bo->nents = bo->pages->nents;
+	}
+
+	bo->ents = kmalloc_array(bo->nents, sizeof(struct virtio_gpu_mem_entry),
+				 GFP_KERNEL);
+	if (!bo->ents) {
+		DRM_ERROR("failed to allocate ent list\n");
+		return -ENOMEM;
+	}
+
+	for_each_sg(bo->pages->sgl, sg, bo->nents, si) {
+		bo->ents[si].addr = cpu_to_le64(use_dma_api
+						? sg_dma_address(sg)
+						: sg_phys(sg));
+		bo->ents[si].length = cpu_to_le32(sg->length);
+		bo->ents[si].padding = 0;
+	}
+	return 0;
+}
+
 int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
 			     struct virtio_gpu_object_params *params,
 			     struct virtio_gpu_object **bo_ptr,
@@ -165,6 +208,12 @@ int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
 					       objs, fence);
 	}
 
+	ret = virtio_gpu_object_shmem_init(vgdev, bo);
+	if (ret != 0) {
+		virtio_gpu_free_object(&shmem_obj->base);
+		return ret;
+	}
+
 	ret = virtio_gpu_object_attach(vgdev, bo, NULL);
 	if (ret != 0) {
 		virtio_gpu_free_object(&shmem_obj->base);
diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index e258186bedb2..7db91376f2f2 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -1081,54 +1081,11 @@ int virtio_gpu_object_attach(struct virtio_gpu_device *vgdev,
 			     struct virtio_gpu_object *obj,
 			     struct virtio_gpu_fence *fence)
 {
-	bool use_dma_api = !virtio_has_iommu_quirk(vgdev->vdev);
-	struct virtio_gpu_mem_entry *ents;
-	struct scatterlist *sg;
-	int si, nents, ret;
-
-	if (WARN_ON_ONCE(!obj->created))
-		return -EINVAL;
-	if (WARN_ON_ONCE(obj->pages))
-		return -EINVAL;
-
-	ret = drm_gem_shmem_pin(&obj->base.base);
-	if (ret < 0)
-		return -EINVAL;
-
-	obj->pages = drm_gem_shmem_get_sg_table(&obj->base.base);
-	if (obj->pages == NULL) {
-		drm_gem_shmem_unpin(&obj->base.base);
-		return -EINVAL;
-	}
-
-	if (use_dma_api) {
-		obj->mapped = dma_map_sg(vgdev->vdev->dev.parent,
-					 obj->pages->sgl, obj->pages->nents,
-					 DMA_TO_DEVICE);
-		nents = obj->mapped;
-	} else {
-		nents = obj->pages->nents;
-	}
-
-	/* gets freed when the ring has consumed it */
-	ents = kmalloc_array(nents, sizeof(struct virtio_gpu_mem_entry),
-			     GFP_KERNEL);
-	if (!ents) {
-		DRM_ERROR("failed to allocate ent list\n");
-		return -ENOMEM;
-	}
-
-	for_each_sg(obj->pages->sgl, sg, nents, si) {
-		ents[si].addr = cpu_to_le64(use_dma_api
-					    ? sg_dma_address(sg)
-					    : sg_phys(sg));
-		ents[si].length = cpu_to_le32(sg->length);
-		ents[si].padding = 0;
-	}
-
 	virtio_gpu_cmd_resource_attach_backing(vgdev, obj->hw_res_handle,
-					       ents, nents,
+					       obj->ents, obj->nents,
 					       fence);
+	obj->ents = NULL;
+	obj->nents = 0;
 	return 0;
 }
 
-- 
2.18.1

Re: [PATCH 2/4] drm/virtio: resource teardown tweaks

[Chia-I Wu]

On Wed, Feb 5, 2020 at 3:00 AM Gerd Hoffmann <kraxel@redhat.com> wrote:
>
> Add new virtio_gpu_cleanup_object() helper function for object cleanup.
> Wire up callback function for resource unref, do cleanup from callback
> when we know the host stopped using the resource.
>
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  drivers/gpu/drm/virtio/virtgpu_drv.h    |  3 ++-
>  drivers/gpu/drm/virtio/virtgpu_object.c | 19 ++++++++++----
>  drivers/gpu/drm/virtio/virtgpu_vq.c     | 35 ++++++++++++++++++++++---
>  3 files changed, 48 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
> index 7e69c06e168e..372dd248cf02 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_drv.h
> +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
> @@ -262,7 +262,7 @@ void virtio_gpu_cmd_create_resource(struct virtio_gpu_device *vgdev,
>                                     struct virtio_gpu_object_array *objs,
>                                     struct virtio_gpu_fence *fence);
>  void virtio_gpu_cmd_unref_resource(struct virtio_gpu_device *vgdev,
> -                                  uint32_t resource_id);
> +                                  struct virtio_gpu_object *bo);
>  void virtio_gpu_cmd_transfer_to_host_2d(struct virtio_gpu_device *vgdev,
>                                         uint64_t offset,
>                                         uint32_t width, uint32_t height,
> @@ -355,6 +355,7 @@ void virtio_gpu_fence_event_process(struct virtio_gpu_device *vdev,
>                                     u64 last_seq);
>
>  /* virtio_gpu_object */
> +void virtio_gpu_cleanup_object(struct virtio_gpu_object *bo);
>  struct drm_gem_object *virtio_gpu_create_object(struct drm_device *dev,
>                                                 size_t size);
>  int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
> diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
> index 017a9e0fc3bb..28a161af7503 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_object.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_object.c
> @@ -61,6 +61,14 @@ static void virtio_gpu_resource_id_put(struct virtio_gpu_device *vgdev, uint32_t
>         }
>  }
>
> +void virtio_gpu_cleanup_object(struct virtio_gpu_object *bo)
> +{
> +       struct virtio_gpu_device *vgdev = bo->base.base.dev->dev_private;
> +
> +       virtio_gpu_resource_id_put(vgdev, bo->hw_res_handle);
> +       drm_gem_shmem_free_object(&bo->base.base);
> +}
> +
>  static void virtio_gpu_free_object(struct drm_gem_object *obj)
>  {
>         struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj);
> @@ -68,11 +76,12 @@ static void virtio_gpu_free_object(struct drm_gem_object *obj)
>
>         if (bo->pages)
>                 virtio_gpu_object_detach(vgdev, bo);
> -       if (bo->created)
> -               virtio_gpu_cmd_unref_resource(vgdev, bo->hw_res_handle);
> -       virtio_gpu_resource_id_put(vgdev, bo->hw_res_handle);
> -
> -       drm_gem_shmem_free_object(obj);
> +       if (bo->created) {
> +               virtio_gpu_cmd_unref_resource(vgdev, bo);
> +               /* completion handler calls virtio_gpu_cleanup_object() */
nitpick: we don't need this comment when virtio_gpu_cmd_unref_cb is
defined by this file and passed to virtio_gpu_cmd_unref_resource.

I happen to be looking at our error handling paths.  I think we want
virtio_gpu_queue_fenced_ctrl_buffer to call vbuf->resp_cb on errors.


> +               return;
> +       }
> +       virtio_gpu_cleanup_object(bo);
>  }
>
>  static const struct drm_gem_object_funcs virtio_gpu_gem_funcs = {
> diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
> index 6d6d55dc384e..6e8097e4c214 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_vq.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
> @@ -152,6 +152,15 @@ static void *virtio_gpu_alloc_cmd(struct virtio_gpu_device *vgdev,
>                                          sizeof(struct virtio_gpu_ctrl_hdr), NULL);
>  }
>
> +static void *virtio_gpu_alloc_cmd_cb(struct virtio_gpu_device *vgdev,
> +                                    struct virtio_gpu_vbuffer **vbuffer_p,
> +                                    int size,
> +                                    virtio_gpu_resp_cb cb)
> +{
> +       return virtio_gpu_alloc_cmd_resp(vgdev, cb, vbuffer_p, size,
> +                                        sizeof(struct virtio_gpu_ctrl_hdr), NULL);
> +}
> +
>  static void free_vbuf(struct virtio_gpu_device *vgdev,
>                       struct virtio_gpu_vbuffer *vbuf)
>  {
> @@ -494,17 +503,37 @@ void virtio_gpu_cmd_create_resource(struct virtio_gpu_device *vgdev,
>         bo->created = true;
>  }
>
> +static void virtio_gpu_cmd_unref_cb(struct virtio_gpu_device *vgdev,
> +                                   struct virtio_gpu_vbuffer *vbuf)
> +{
> +       struct virtio_gpu_object *bo;
> +
> +       bo = gem_to_virtio_gpu_obj(vbuf->objs->objs[0]);
> +       kfree(vbuf->objs);
> +       vbuf->objs = NULL;
> +
> +       virtio_gpu_cleanup_object(bo);
> +}
> +
>  void virtio_gpu_cmd_unref_resource(struct virtio_gpu_device *vgdev,
> -                                  uint32_t resource_id)
> +                                  struct virtio_gpu_object *bo)
>  {
>         struct virtio_gpu_resource_unref *cmd_p;
>         struct virtio_gpu_vbuffer *vbuf;
>
> -       cmd_p = virtio_gpu_alloc_cmd(vgdev, &vbuf, sizeof(*cmd_p));
> +       cmd_p = virtio_gpu_alloc_cmd_cb(vgdev, &vbuf, sizeof(*cmd_p),
> +                                       virtio_gpu_cmd_unref_cb);
>         memset(cmd_p, 0, sizeof(*cmd_p));
>
>         cmd_p->hdr.type = cpu_to_le32(VIRTIO_GPU_CMD_RESOURCE_UNREF);
> -       cmd_p->resource_id = cpu_to_le32(resource_id);
> +       cmd_p->resource_id = cpu_to_le32(bo->hw_res_handle);
> +
> +       /*
> +        * We are in the release callback and do NOT want refcount
> +        * bo, so do NOT use virtio_gpu_array_add_obj().
> +        */
> +       vbuf->objs = virtio_gpu_array_alloc(1);
> +       vbuf->objs->objs[0] = &bo->base.base
This is an abuse of obj array.  Add "void *private_data;" to
virtio_gpu_vbuffer and use that maybe?

Otherwise, simply

  // abuse objs field to pass our private data; must reset in the resp_cb
  vbuf->objs = (virtio_gpu_object_array *) bo;

makes it easier to see what is going on.


>
>         virtio_gpu_queue_ctrl_buffer(vgdev, vbuf);
>  }
> --
> 2.18.1
>

Re: [PATCH 4/4] drm/virtio: move virtio_gpu_mem_entry initialization to new function

[Chia-I Wu]

On Wed, Feb 5, 2020 at 3:00 AM Gerd Hoffmann <kraxel@redhat.com> wrote:
>
> Introduce new virtio_gpu_object_shmem_init() helper function which will
> create the virtio_gpu_mem_entry array, containing the backing storage
> information for the host.  For the most path this just moves code from
> virtio_gpu_object_attach().
>
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  drivers/gpu/drm/virtio/virtgpu_drv.h    |  4 ++
>  drivers/gpu/drm/virtio/virtgpu_object.c | 49 +++++++++++++++++++++++++
>  drivers/gpu/drm/virtio/virtgpu_vq.c     | 49 ++-----------------------
>  3 files changed, 56 insertions(+), 46 deletions(-)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
> index 15fb3c12f22f..be62a7469b04 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_drv.h
> +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
> @@ -71,6 +71,10 @@ struct virtio_gpu_object {
>
>         struct sg_table *pages;
>         uint32_t mapped;
> +
> +       struct virtio_gpu_mem_entry *ents;
> +       unsigned int nents;
> +
>         bool dumb;
>         bool created;
>  };
> diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
> index bce2b3d843fe..4e82e269a1f4 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_object.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_object.c
> @@ -121,6 +121,49 @@ struct drm_gem_object *virtio_gpu_create_object(struct drm_device *dev,
>         return &bo->base.base;
>  }
>
> +static int virtio_gpu_object_shmem_init(struct virtio_gpu_device *vgdev,
> +                                       struct virtio_gpu_object *bo)
> +{
> +       bool use_dma_api = !virtio_has_iommu_quirk(vgdev->vdev);
> +       struct scatterlist *sg;
> +       int si, ret;
> +
> +       ret = drm_gem_shmem_pin(&bo->base.base);
> +       if (ret < 0)
> +               return -EINVAL;
> +
> +       bo->pages = drm_gem_shmem_get_sg_table(&bo->base.base);
> +       if (bo->pages == NULL) {
> +               drm_gem_shmem_unpin(&bo->base.base);
> +               return -EINVAL;
> +       }
> +
> +       if (use_dma_api) {
> +               bo->mapped = dma_map_sg(vgdev->vdev->dev.parent,
> +                                        bo->pages->sgl, bo->pages->nents,
> +                                        DMA_TO_DEVICE);
> +               bo->nents = bo->mapped;
> +       } else {
> +               bo->nents = bo->pages->nents;
> +       }
> +
> +       bo->ents = kmalloc_array(bo->nents, sizeof(struct virtio_gpu_mem_entry),
> +                                GFP_KERNEL);
> +       if (!bo->ents) {
> +               DRM_ERROR("failed to allocate ent list\n");
> +               return -ENOMEM;
> +       }
> +
> +       for_each_sg(bo->pages->sgl, sg, bo->nents, si) {
> +               bo->ents[si].addr = cpu_to_le64(use_dma_api
> +                                               ? sg_dma_address(sg)
> +                                               : sg_phys(sg));
> +               bo->ents[si].length = cpu_to_le32(sg->length);
> +               bo->ents[si].padding = 0;
> +       }
> +       return 0;
> +}
> +
>  int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
>                              struct virtio_gpu_object_params *params,
>                              struct virtio_gpu_object **bo_ptr,
> @@ -165,6 +208,12 @@ int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
>                                                objs, fence);
>         }
>
> +       ret = virtio_gpu_object_shmem_init(vgdev, bo);
> +       if (ret != 0) {
> +               virtio_gpu_free_object(&shmem_obj->base);
> +               return ret;
> +       }
> +
>         ret = virtio_gpu_object_attach(vgdev, bo, NULL);
>         if (ret != 0) {
>                 virtio_gpu_free_object(&shmem_obj->base);
> diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
> index e258186bedb2..7db91376f2f2 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_vq.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
> @@ -1081,54 +1081,11 @@ int virtio_gpu_object_attach(struct virtio_gpu_device *vgdev,
>                              struct virtio_gpu_object *obj,
>                              struct virtio_gpu_fence *fence)
>  {
> -       bool use_dma_api = !virtio_has_iommu_quirk(vgdev->vdev);
> -       struct virtio_gpu_mem_entry *ents;
> -       struct scatterlist *sg;
> -       int si, nents, ret;
> -
> -       if (WARN_ON_ONCE(!obj->created))
> -               return -EINVAL;
> -       if (WARN_ON_ONCE(obj->pages))
> -               return -EINVAL;
> -
> -       ret = drm_gem_shmem_pin(&obj->base.base);
> -       if (ret < 0)
> -               return -EINVAL;
> -
> -       obj->pages = drm_gem_shmem_get_sg_table(&obj->base.base);
> -       if (obj->pages == NULL) {
> -               drm_gem_shmem_unpin(&obj->base.base);
> -               return -EINVAL;
> -       }
> -
> -       if (use_dma_api) {
> -               obj->mapped = dma_map_sg(vgdev->vdev->dev.parent,
> -                                        obj->pages->sgl, obj->pages->nents,
> -                                        DMA_TO_DEVICE);
> -               nents = obj->mapped;
> -       } else {
> -               nents = obj->pages->nents;
> -       }
> -
> -       /* gets freed when the ring has consumed it */
> -       ents = kmalloc_array(nents, sizeof(struct virtio_gpu_mem_entry),
> -                            GFP_KERNEL);
> -       if (!ents) {
> -               DRM_ERROR("failed to allocate ent list\n");
> -               return -ENOMEM;
> -       }
> -
> -       for_each_sg(obj->pages->sgl, sg, nents, si) {
> -               ents[si].addr = cpu_to_le64(use_dma_api
> -                                           ? sg_dma_address(sg)
> -                                           : sg_phys(sg));
> -               ents[si].length = cpu_to_le32(sg->length);
> -               ents[si].padding = 0;
> -       }
> -
>         virtio_gpu_cmd_resource_attach_backing(vgdev, obj->hw_res_handle,
> -                                              ents, nents,
> +                                              obj->ents, obj->nents,
>                                                fence);
> +       obj->ents = NULL;
> +       obj->nents = 0;
Hm, if the entries are temporary, can we allocate and initialize them
in this function?

virtio_gpu_object_shmem_init will just pin and map pages.  Maybe
rename it to virtio_gpu_object_pin_pages (and add a helper
virtio_gpu_object_unpin_pages for use by virtio_gpu_cleanup_object).

Because we pin pages on object creation, virtio_gpu_gem_funcs does not
need to provide the optional pin/unpin hooks.

>         return 0;
>  }
>
> --
> 2.18.1
>

Re: [PATCH 2/4] drm/virtio: resource teardown tweaks

[Gerd Hoffmann]

> > -
> > -       drm_gem_shmem_free_object(obj);
> > +       if (bo->created) {
> > +               virtio_gpu_cmd_unref_resource(vgdev, bo);
> > +               /* completion handler calls virtio_gpu_cleanup_object() */
> nitpick: we don't need this comment when virtio_gpu_cmd_unref_cb is
> defined by this file and passed to virtio_gpu_cmd_unref_resource.

I want virtio_gpu_cmd_unref_cb + virtio_gpu_cmd_unref_resource being
placed next to each other so it is easier to see how they work hand in
hand.

> I happen to be looking at our error handling paths.  I think we want
> virtio_gpu_queue_fenced_ctrl_buffer to call vbuf->resp_cb on errors.

/me was thinking about that too.  Yes, we will need either that,
or a separate vbuf->error_cb callback.  That'll be another patch
though.

> > +       /*
> > +        * We are in the release callback and do NOT want refcount
> > +        * bo, so do NOT use virtio_gpu_array_add_obj().
> > +        */
> > +       vbuf->objs = virtio_gpu_array_alloc(1);
> > +       vbuf->objs->objs[0] = &bo->base.base
> This is an abuse of obj array.  Add "void *private_data;" to
> virtio_gpu_vbuffer and use that maybe?

I'd name that *cb_data, but yes, that makes sense.

cheers,
  Gerd

Re: [PATCH 4/4] drm/virtio: move virtio_gpu_mem_entry initialization to new function

[Gerd Hoffmann]

  Hi,

> >         virtio_gpu_cmd_resource_attach_backing(vgdev, obj->hw_res_handle,
> > -                                              ents, nents,
> > +                                              obj->ents, obj->nents,
> >                                                fence);
> > +       obj->ents = NULL;
> > +       obj->nents = 0;
> Hm, if the entries are temporary, can we allocate and initialize them
> in this function?

Well, the plan for CREATE_RESOURCE_BLOB is to use obj->ents too ...

cheers,
  Gerd

Re: [PATCH 2/4] drm/virtio: resource teardown tweaks

[Chia-I Wu]

On Wed, Feb 5, 2020 at 10:43 PM Gerd Hoffmann <kraxel@redhat.com> wrote:
>
> > > -
> > > -       drm_gem_shmem_free_object(obj);
> > > +       if (bo->created) {
> > > +               virtio_gpu_cmd_unref_resource(vgdev, bo);
> > > +               /* completion handler calls virtio_gpu_cleanup_object() */
> > nitpick: we don't need this comment when virtio_gpu_cmd_unref_cb is
> > defined by this file and passed to virtio_gpu_cmd_unref_resource.
>
> I want virtio_gpu_cmd_unref_cb + virtio_gpu_cmd_unref_resource being
> placed next to each other so it is easier to see how they work hand in
> hand.
>
> > I happen to be looking at our error handling paths.  I think we want
> > virtio_gpu_queue_fenced_ctrl_buffer to call vbuf->resp_cb on errors.
>
> /me was thinking about that too.  Yes, we will need either that,
> or a separate vbuf->error_cb callback.  That'll be another patch
> though.
Or the new virtio_gpu_queue_ctrl_sgs can return errors rather than
eating errors.

Yeah, that should be another patch.
>
> > > +       /*
> > > +        * We are in the release callback and do NOT want refcount
> > > +        * bo, so do NOT use virtio_gpu_array_add_obj().
> > > +        */
> > > +       vbuf->objs = virtio_gpu_array_alloc(1);
> > > +       vbuf->objs->objs[0] = &bo->base.base
> > This is an abuse of obj array.  Add "void *private_data;" to
> > virtio_gpu_vbuffer and use that maybe?
>
> I'd name that *cb_data, but yes, that makes sense.
Sounds great.
>
> cheers,
>   Gerd
>

Re: [PATCH 4/4] drm/virtio: move virtio_gpu_mem_entry initialization to new function

[Chia-I Wu]

On Thu, Feb 6, 2020 at 12:55 AM Gerd Hoffmann <kraxel@redhat.com> wrote:
>
>   Hi,
>
> > >         virtio_gpu_cmd_resource_attach_backing(vgdev, obj->hw_res_handle,
> > > -                                              ents, nents,
> > > +                                              obj->ents, obj->nents,
> > >                                                fence);
> > > +       obj->ents = NULL;
> > > +       obj->nents = 0;
> > Hm, if the entries are temporary, can we allocate and initialize them
> > in this function?
>
> Well, the plan for CREATE_RESOURCE_BLOB is to use obj->ents too ...
Is obj->ents needed after CREATE_RESOURCE_BLOB?  If not, having yet
another helper

  ents = virtio_gpu_object_alloc_mem_entries(..., &count);

seems cleaner.  We would also be able to get rid of virtio_gpu_object_attach.

>
> cheers,
>   Gerd
>