Re: [PATCH v0 0/2] virtio-blk and vhost-user-blk cross-device migration

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Michael S. Tsirkin (mst@redhat.com) wrote:
> On Wed, Oct 06, 2021 at 09:28:50AM +0100, Dr. David Alan Gilbert wrote:
> > To me it feels the same as the distinction between vhost-kernel and qemu
> > backended virtio that we get in net and others - in principal it's just 
> > another implementation.
> 
> In net it's actually like this. Same -device, a different netdev.
> 
> > A tricky part is guaranteeing the set of visible virtio features between
> > implementations; we have that problem when we use vhost-kernel and run
> > on a newer/older kernel and gain virtio features; the same will be true
> > with vhost-user implementations.
> 
> That's not new but yes we need to work on this.
> 
> > But this would make the structure of a vhost-user implementation quite
> > different.
> > 
> > Dave
> 
> Right. That's why I'm reluctant to just add a new device type that
> has special compatibility requirements.

Hmm but there's already another layer of hack^Wabstraction in there isn't there -
there's already:
    virtio-blk-pci
    virtio-blk-device

created when the user specifies a virtio-blk device?

Dave


> > > 
> > > > > -- 
> > > > > MST
> > > > > 
> > > > -- 
> > > > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> > > 
> > -- 
> > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK