Re: [PATCH v8 4/4] drm/virtio: wire blob ioctl creation to userptr objects

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] drm/virtio: resource loss on resume for userptr blobs
--

commit 260e023045965d09441bfc27b3e47cf7b409d5b4
Author: Honglei Huang <honghuan@amd.com>

drm/virtio: wire blob ioctl creation to userptr objects

This commit integrates userptr into the blob resource creation ioctl.
It adds validation and wires up virtio_gpu_userptr_create() for guest
blob allocations.

> diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
[ ... ]
> @@ -538,7 +561,9 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
>  				      vfpriv->ctx_id, NULL, NULL);
>  	}
>  
> -	if (guest_blob)
> +	if (guest_blob && params.userptr)
> +		ret = virtio_gpu_userptr_create(vgdev, file, &params, &bo);

[Severity: High]
Does this code handle system hibernation properly for userptr objects?

When virtio_gpu_userptr_create() in drivers/gpu/drm/virtio/virtgpu_userptr.c
successfully allocates the object, it returns without saving bo->params or
calling virtio_gpu_add_object_to_restore_list():

	virtio_gpu_cmd_resource_create_blob(vgdev, &userptr->base, params, ents,
					    nents);

	*bo_ptr = &userptr->base;
	return 0;

Consequently, these objects are permanently lost when the system resumes from
hibernation because their host-side resources are not re-created. Subsequent
GPU commands referencing these resources will fail.

Additionally, if these userptr objects were added to the obj_restore_list, it
seems virtio_gpu_object_restore_all() in drivers/gpu/drm/virtio/virtgpu_object.c
would crash:

	if (bo->params.blob || bo->attached) {
		ret = virtio_gpu_object_shmem_init(vgdev, bo, &ents,
						   &nents);
		if (ret)
			break;
	}

This logic assumes all non-imported blobs are backed by drm_gem_shmem_object,
but userptr blobs are not.

> +	else if (guest_blob)
>  		ret = virtio_gpu_object_create(vgdev, &params, &bo, NULL);
>  	else if (!guest_blob && host3d_blob)
>  		ret = virtio_gpu_vram_create(vgdev, &params, &bo);

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260918075600.2197253-1-honghuan@amd.com?part=4