Re: [virtio] [PATCH v3 1/1] virtio-ccw: introduce revisions

[Cornelia Huck <cornelia.huck@de.ibm.com>]

On Tue, 05 Nov 2013 16:59:19 +1030
Rusty Russell <rusty@au1.ibm.com> wrote:

> Cornelia Huck <cornelia.huck@de.ibm.com> writes:
> > Provide a new ccw that allows devices and drivers to operate on selected
> > revision levels.
> >
> > VIRTIO-42
> >
> > Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
> >
> > ---
> >
> > Changes v2 -> v3:
> >  - Reset will not clear the revision; instead, the revision is cleared
> >    when the subchannel is disabled
> 
> Does this work properly across kexec scenarios?

Kexec on s390 will do a diagnose (hypercall) that triggers (among other
things) a channel subsystem reset, which in turn includes disabling all
subchannels. This means the kexeced guest will be presented with an
unset revision.

> 
> Cheers,
> Rusty.