Re: [PATCH v2 08/22] vfio: Enforce preserved devices are retrieved via LIVEUPDATE_SESSION_RETRIEVE_FD

[Alex Williamson]

On Thu, 26 Feb 2026 23:27:47 +0000
David Matlack <dmatlack@xxxxxxxxxx> wrote:

> On 2026-02-26 04:15 PM, Alex Williamson wrote:
> > On Thu, 29 Jan 2026 21:24:55 +0000 David Matlack <dmatlack@xxxxxxxxxx> wrote:  
> 
> > > +	/*
> > > +	 * This device was preserved across a Live Update. Accessing it via
> > > +	 * VFIO_GROUP_GET_DEVICE_FD is not allowed.
> > > +	 */
> > > +	if (vfio_liveupdate_incoming_is_preserved(device)) {
> > > +		vfio_device_put_registration(device);
> > > +		return -EBUSY;  
> > 
> > Is this an EPERM issue then?  
> 
> I was thinking EBUSY in the sense that the device is only temporarily
> inaccesible through this interface due it being in a preserved state as
> part of a Live Update. Once the preserved device file is retreived and
> closed, the device can be accessed again through
> VFIO_GROUP_GET_DEVICE_FD.
> 
> EPERM might lead to confusion that there is a filesystem permission
> issue?

Ok, fair explanation.  Thanks,

Alex