Re: [PATCH] virtio-ccw: commands on revision-less devices

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

On Tue, Feb 16, 2021 at 12:51:50PM +0100, Cornelia Huck wrote:
> On Tue, 16 Feb 2021 06:40:41 -0500
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
> 
> > On Tue, Feb 16, 2021 at 12:18:30PM +0100, Cornelia Huck wrote:
> > > The virtio standard specifies that any non-transitional device must
> > > reject commands prior to revision setting (which we do) and else
> > > assume revision 0 (legacy) if the driver sends a non-revision-setting
> > > command first. We neglected to do the latter.
> > > 
> > > Fortunately, nearly everything worked as intended anyway; the only
> > > problem was not properly rejecting revision setting after some other
> > > command had been issued. Easy to fix by setting revision to 0 if
> > > we see a non-revision command on a legacy-capable revision-less
> > > device.
> > > 
> > > Signed-off-by: Cornelia Huck <cohuck@redhat.com>  
> > 
> > Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
> > 
> > Feel free to merge.
> > 
> > Curious how was this discovered.
> 
> Code reading :)
> 
> I have not seen any errors in the wild.

Worth including in the commit log.

-- 
MST