Re: [Qemu-devel] [RFC] virtio-mmio: implement modern (v2) personality (virtio-1)

[Cornelia Huck]

On Wed, 31 Jul 2019 15:06:11 -0400
"Michael S. Tsirkin" <address@hidden> wrote:

> On Wed, Jul 31, 2019 at 03:55:51PM +0200, Cornelia Huck wrote:
> > On Tue, 30 Jul 2019 16:18:52 -0400
> > "Michael S. Tsirkin" <address@hidden> wrote:

> > > Make sure your guests
> > > are all up to date in preparation to the day when legacy will go away.  
> > 
> > If legacy goes away, legacy guests will be busted anyway :)  
> 
> It'll take a while for it to go away. But we can try to
> push guests in the direction of coding up modern
> support e.g. by forcing modern by default.

Actually, ccw defaulted to transitional devices right back when we
introduced support for virtio-1 - starting with QEMU 2.5.

I'm not sure how many (if any) supported guest OSs (various variants of
Linux) support virtio-ccw devices in legacy mode only. We can probably
neglect that issue, but I would not really complain if someone
submitted a patch to optionally turn off legacy support for ccw.