Re: [virtio] RE: [virtio-comment] Re: [virtio] Re: [PATCH v10 04/10] admin: introduce virtio admin virtqueues

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

On Wed, Mar 08, 2023 at 01:17:44PM +0800, Jason Wang wrote:
> On Wed, Mar 8, 2023 at 3:09âAM Parav Pandit <parav@nvidia.com> wrote:
> >
> >
> >
> > > From: Stefan Hajnoczi <stefanha@redhat.com>
> > > Sent: Tuesday, March 7, 2023 2:04 PM
> >
> > > An alternative is unconditional out-of-order completion, where there are no
> > > per-command ordering rules. The driver must wait for a command to complete
> > > if it relies on the results of that command for its next command. I like this
> > > approach because it's less complex in the spec and for device implementers,
> > > while the burden on the driver implementer is still reasonable.
> > +1.
> 
> Note that this is the way current ctrl virtqueue works.
> 
> > This has best of both.
> > 1. Command ordering knowledge and hence the decision left to the one which issues them. (driver).
> > 2. Ability to execute multiple unrelated commands using a single AQ.
> > 3. stateless device in AQ command execution
> 
> Does this mean if we want to migrate AQ (not use AQ to migrate), we
> need to wait for the AQ command to be completed?
> 
> Thanks

As with any VQ, if you migrate while an operation is in progress
you need to figure out the internal device state.

> >
> >
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