Re: [PATCH v6 06/11] qapi: add failover negotiated event

[Jens Freimann]

On Fri, Oct 25, 2019 at 04:03:54PM +0200, Markus Armbruster wrote:
> Bear with me, I know next to nothing about failover.
>
> Jens Freimann <address@hidden> writes:
>
> > This event is sent to let libvirt know that VIRTIO_NET_F_STANDBY feature
> > was enabled. The primary device this virtio-net device is associated
> > with, will now be hotplugged via qdev_device_add().
>
> Passive voice deftly avoids telling the reader who will do the
> hot-plugging.  Intentional?

Not really, it's in the comment to the event. The hotplug will be
done by the virtio-net device code that activates the feature, in
virtio_net_set_features().

> > Signed-off-by: Jens Freimann <address@hidden>
> > Acked-by: Cornelia Huck <address@hidden>
> > ---
> >  qapi/net.json | 19 +++++++++++++++++++
> >  1 file changed, 19 insertions(+)
> >
> > diff --git a/qapi/net.json b/qapi/net.json
> > index 728990f4fb..ea6eeee4f7 100644
> > --- a/qapi/net.json
> > +++ b/qapi/net.json
> > @@ -737,3 +737,22 @@
> >  ##
> >  { 'command': 'announce-self', 'boxed': true,
> >    'data' : 'AnnounceParameters'}
> > +
> > +##
> > +# @FAILOVER_NEGOTIATED:
> > +#
> > +# Emitted when VIRTIO_NET_F_STANDBY was enabled during feature negotiation.
> > +# Failover primary devices which were hidden (not hotplugged when requested)
> > +# before will now be hotplugged by the virtio-net standby device.
> > +#
> > +# device-id: QEMU device id of the unplugged device
>
> @device-id is new since v5.
>
> A quick skim of
> https://www.kernel.org/doc/html/latest/networking/net_failover.html
> tells me there are three devices involved: master, primary slave,
> standby slave.  Which one is @device-id?  Or am I confused?

Yes, the device-id is new and it's the device-id of the standby (i.e.
virtio-net) device.

regards,
Jens