On Mon, Jul 17, 2023 at 01:08:31PM -0600, Alex Williamson wrote: > What would that mechanism be? We've been iterating on getting the > serialization and buffering correct, but I don't know of another means > that combines the notification with a value, so we'd likely end up with > an eventfd only for notification and a separate ring buffer for > notification values. All FDs do this. You just have to make a FD with custom file_operations that does what this wants. The uAPI shouldn't be able to tell if the FD is backing it with an eventfd or otherwise. Have the kernel return the FD instead of accepting it. Follow the basic design of eg mlx5vf_save_fops Jason