On Tue, Oct 01, 2019 at 06:49:35PM -0700, Gurchetan Singh wrote:
This doesn't really break userspace, since it always passes down 0 for stride/layer_stride currently. We could:
(1) modify UAPI now and add a VIRTGPU_PARAM_STRIDE_FIX feature
This I think. But IMO it's not a fix, it is an added feature ...
Also missing the big picture here. Why do we need this?
For guest object we don't have strides (virtio_gpu_resource_create_3d doesn't allow this).
For host objects the host should know the strides.
Which I think is the reason why the stride and layer_stride fields in the transfer commands are effectively unused ...
- /* TODO: add the correct stride / layer_stride. */ virtio_gpu_cmd_transfer_from_host_3d
(vgdev, vfpriv->ctx_id, offset, args->level, 0, 0,&box, objs, fence);
(vgdev, vfpriv->ctx_id, offset, args->level, args->stride,args->layer_stride, &box, objs, fence);
What happens with old userspace running on a new kernel?
I don't think we can simply use the args here without checking we actually got something from userspace ...
diff --git a/include/uapi/drm/virtgpu_drm.h b/include/uapi/drm/virtgpu_drm.h index f06a789f34cd..b2fc92c3d2be 100644 --- a/include/uapi/drm/virtgpu_drm.h +++ b/include/uapi/drm/virtgpu_drm.h @@ -117,6 +117,8 @@ struct drm_virtgpu_3d_transfer_to_host { struct drm_virtgpu_3d_box box; __u32 level; __u32 offset;
- __u32 stride;
- __u32 layer_stride;
};
cheers, Gerd