Re: [Qemu-devel] [PATCH] s390x: Switch to s390-ccw machine as default

[Aurelien Jarno <aurelien@aurel32.net>]

On 2015-06-17 16:00, Christian Borntraeger wrote:
> Am 17.06.2015 um 15:46 schrieb Aurelien Jarno:
> > On 2015-06-16 23:08, Alexander Graf wrote:
> >> We now finally have TCG support for the basic set of instructions necessary
> >> to run the s390-ccw machine. That means in any aspect possible that machine
> >> type is now superior to the legacy s390-virtio machine.
> >>
> >> Switch over to the ccw machine as default. That way people don't get a halfway
> >> broken machine with the s390x target.
> > 
> > It seems the current s390x-ccw firmware doesn't allow to boot on a
> > virtio-scsi-ccw disk (but this is not a regression compared to the
> > s390-virtio machine). virtio-scsi has some advantages over virtio-blk,
> > like the possibility to do thin-provisioning. Of course one can use a
> > small virtio-blk for the /boot partition, and virtio-scsi for the
> > remaining disks.
> > 
> > Do you think it would possible to add it? Given a virtio-scsi device can
> > provide multiple disks, how can we pass the disk to boot on to the
> > firmware? Currently it seems we pass the ccw device in GR7, but not more
> > details.
> 
> Yes, we look into that, Integrating this into s390 specifics without adding
> hacks that have to last forever will take most of the time. We have to 
> consider aspects like loadparm, the existing interfaces for the zfcp
> connectivity in the diag308 handler and so on (so that /sys/firmware/ipl/
> reflects the disks) - so give us some time to do it properly to see
> how this can be integrated.

Great, thanks for working on that.

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                 http://www.aurel32.net