Re: [Qemu-devel] qemu-system-s390x command line

[Richard W.M. Jones]

On Sun, Aug 30, 2015 at 11:02:17PM +0200, Alexander Graf wrote:
> 
> 
> > Am 30.08.2015 um 22:11 schrieb Richard W.M. Jones <address@hidden>:
> > 
> > Hi Alex,
> > 
> > Do you or anyone have a working qemu-system-s390x command line I can
> > use as a starting point to boot a [TCG] guest?
> > 
> > So far I have tried variations of:
> > 
> > ~/d/qemu/s390x-softmmu/qemu-system-s390x -M s390-ccw-virtio -m 1024 -smp 1 
> > -drive file=s390x.img,if=none,id=disk0 -device 
> > virtio-blk-ccw,drive=disk0,id=hd0,bootindex=1 -drive 
> > file=Fedora-Server-DVD-s390x-22.iso
>
> Ok, 2 problems here. I'm not sure the iso is bootable - you are
> definitely best off to just use -kernel until you have sonething
> working and then move on to booting without. CD boot is something
> real mainframes don't do very often, so it's a pretty unmaintained
> code path in installation media.
>
> The other one is that we emulate most fancy new user level
> instructions of an ec12, but we only advertise ourselves as a z9 to
> the kernel. So you need to make sure that your kernel is compiled
> with support for old CPUs (RHEL7 for example is not).

Thanks Alex.  Stripping this back to the basics:

  ~/d/qemu/s390x-softmmu/qemu-system-s390x -M s390-ccw-virtio -m 1024 -smp 1 
-kernel kernel.img

with the kernel.img downloaded from

  http://mirrors.nic.cz/fedora-secondary/releases/22/Server/s390x/os/images/

just opens a window for a fraction of a second and then qemu exits.

I'm not married to that particular kernel, nor even to Fedora.  I just
want to get something that works as a starting point.  Is there a SUSE
or Debian kernel which boots?

> Once you get past these points, things should be very
> self-explanatory. Oh - and -kernel is 0 overhead on s390x, unlike
> x86.

Heh heh :-)

Rich.

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