Re: [PATCH V2 3/6] virtio: dont reset vqs when SUSPEND

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

On Tue, Nov 07, 2023 at 05:27:23PM +0800, Zhu, Lingshan wrote:
> 
> 
> On 11/6/2023 5:49 PM, Michael S. Tsirkin wrote:
> > On Fri, Nov 03, 2023 at 06:34:34PM +0800, Zhu Lingshan wrote:
> > > When SUSPEND is set, device states and virtqueue states
> > > should be stablized, therefore the driver should not
> > > reset vqs when SUSPEND is set in device status.
> > > 
> > > Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
> > > ---
> > >   content.tex | 3 +++
> > >   1 file changed, 3 insertions(+)
> > > 
> > > diff --git a/content.tex b/content.tex
> > > index bcc9d4b..060b5c2 100644
> > > --- a/content.tex
> > > +++ b/content.tex
> > > @@ -444,6 +444,9 @@ \subsubsection{Virtqueue Reset}\label{sec:Basic Facilities of a Virtio Device /
> > >   The device MUST reset any state of a virtqueue to the default state,
> > >   including the available state and the used state.
> > > +If VIRTIO_F_SUSPEND is negotiated and SUSPEND is set in \field{device status},
> > > +the driver SHOULD NOT reset any virtqueues.
> > > +
> > >   \drivernormative{\paragraph}{Virtqueue Reset}{Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset / Virtqueue Reset}
> > >   After the driver tells the device to reset a queue, the driver MUST verify that
> > Seems somewhat arbitrary and breaks the claim that the
> > feature is orthogonal and can have uses besides migration.
> when suspended, the device is frozen.
> The driver is aware of this process and so should not reset the vqs I think.

Again that is only true because you want to use it for migration.
But then you can't claim it's a generic facility.

> > 
> > 
> > 
> > > -- 
> > > 2.35.3