On Thu, 10 Sep 2015 12:22:42 +0300 "Michael S. Tsirkin" <m...@redhat.com> wrote:
> On Thu, Sep 10, 2015 at 11:11:20AM +0200, Cornelia Huck wrote: > > On Thu, 10 Sep 2015 12:07:18 +0300 > > "Michael S. Tsirkin" <m...@redhat.com> wrote: > > > > > On Fri, Sep 04, 2015 at 10:54:29AM +0200, Cornelia Huck wrote: > > > > Let's enable revision 1 for virtio-ccw devices. We can always offer > > > > VERSION_1 as drivers in legacy mode won't be able to see it anyway. > > > > > > > > We have to introduce a way to set a lower maximum revision for a device > > > > to accommodate the following cases: > > > > - compat machines (to enforce legacy only) > > > > > > But you don't actually set this for any compat machines. > > > If you don't, this seems a bit pointless. > > > > Huh? The first hunk of this patch does this. > > Sure. Donnu how I could miss it, sorry. > > > > > > > > - virtio-blk with scsi support (version 1 + scsi is fenced by common > > > > code, with a user-configured max revision of 0 we can allow scsi > > > > via not offering VERSION_1) > > > > > > For this use, for pci users need to do disable_modern=true. > > > I find it unfortunate that for ccw one needs to do max_revision=0. > > > > I don't like the pci concept: much too coarse-grained and not very > > future proof. > > > > > > > > Revision numbers generally are a ccw specific concept. I'm not sure it > > > is wise to expose it to users. > > > > What is wrong about exposing transport-specific concepts? > > Nothing. Go ahead and expose as much of the low level as > makes sense. > > But it would be nice if there was also a portable way for people > that just want "virtio" and don't care about the low level details > of which transport it is. Proxy devices already look different depending on what transport you use, so I don't think it really matters. (And for most users, I'd expect they let a management layer take care of it anyway.) > > OTOH a conservative estimate of the # of people that will want > to play with this is pretty close to 0, so maybe it does not matter > much. The scsi vs. virtio-1 on ccw handling? Not very many (if anyone), yes. > > > > > > > > Signed-off-by: Cornelia Huck <cornelia.h...@de.ibm.com> > > > > --- > > > > hw/s390x/s390-virtio-ccw.c | 4 ++++ > > > > hw/s390x/virtio-ccw.c | 30 ++++++++++++++++++++++++++++-- > > > > hw/s390x/virtio-ccw.h | 6 ++++-- > > > > 3 files changed, 36 insertions(+), 4 deletions(-)
