On Mon, Jan 20, 2020 at 04:56:06PM -0500, Michael S. Tsirkin wrote:

quoted

For vfio? vfio is the only thing I am aware doing
that, and this is not vfio..

vfio is not doing anything. anyone can use a combination
of unbind and driver_override to attach a driver to a device.

It's not a great interface but it's there without any code,
and it will stay there without maintainance overhead
if we later add a nicer one.

Well, it is not a great interface, and it is only really used in
normal cases by vfio.

I don't think it is a good idea to design new subsystems with that
idea in mind, particularly since detatching the vdpa driver would not
trigger destruction of the underlying dynamic resource (ie the SF).

We need a way to trigger that destruction..

Jason