Re: [virtio-comment] [PATCH v1 1/8] admin: Add theory of operation for device migration

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Nov 16, 2023 at 06:34:23AM +0000, Parav Pandit wrote:
> 
> 
> > From: Michael S. Tsirkin <mst@redhat.com>
> > Sent: Thursday, November 16, 2023 11:53 AM
> > 
> > On Thu, Nov 16, 2023 at 05:28:19AM +0000, Parav Pandit wrote:
> > > You continue to want to overload admin commands for dual purpose, does
> > not make sense to me.
> > 
> > dual -> as a transport and for migration? why can't they be used for this? I was
> > really hoping to cover these two cases when I proposed them.
> For following reasons.
> 
> 1. migration needs incremental reads of only changed context between two reads
> 
> 2. migration writes covers large part of the configurations not just virtio common config and device config.
> Such as configuration occurred through the CVQ. All of these is not needed when done from guest directly via member's own CVQ.
> 
> For backward compatible SIOV transport, one may need them to transport without above two properties.
> 
> 3. None of this transport is needed for PFs, VFs and non-backward compatible SIOVs.
> Each device to have its own transport that is not intercepted by the hypervisor and follow the equivalency principle uniformly for all 3 device types.
> 

To clarify. Above seems to justify why the admin commands for migration
must be distinct from admin commands for transport. But I don't see why
(e.g. two sets of) admin commands can not be used for both. Do you?

-- 
MST