Re: [Qemu-devel] [PATCH v4 0/2] virtio: Move host features to backends

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

On Tue, Apr 28, 2015 at 07:34:29PM +0100, Peter Maydell wrote:
> On 28 April 2015 at 19:14, Michael S. Tsirkin <mst@redhat.com> wrote:
> > On Tue, Apr 28, 2015 at 04:35:16PM +0200, Michael S. Tsirkin wrote:
> >> On Tue, Apr 28, 2015 at 03:24:19PM +0200, Cornelia Huck wrote:
> >> > Yep, see my other reply... I'm not quite sure what's wrong with
> >> > event_idx on virtio-blk for s390-virtio, or I would gladly make this
> >> > consistent with the other transports. Any hints appreciated :)
> >>
> >> Is this still happening?
> >>
> >> It is possible that what was missing was
> >> 92045d80badc43c9f95897aad675dc7ef17a3b3f
> >> and/or
> >> a281ebc11a6917fbc27e1a93bb5772cd14e241fc
> >>
> >
> > Found this:
> > http://thread.gmane.org/gmane.comp.emulators.qemu/280334/focus=280357
> > so it's unlikely: these commits are from 2012, you saw
> > issues in 2014.
> >
> > We really need to fix it. virtio 1 work will be much easier if
> > we can just move features into virtio dev.
> 
> If the comments in that thread are correct, it suggests that
> *all* s390 virtio devices need to not have event_idx set, ie
> this is not particularly special to virtio-blk. In that case
> could we move the common properties to the base class where
> they belong, but have the s390 virtio base class override
> the properties to always suppress event-idx ?
> 
> -- PMM

That would be a reasonable work-around, yes.
I still hope we can resolve it properly though.

-- 
MST