[Qemu-devel] [PATCH RFC 0/1] s390x: pci compat handling

[Cornelia Huck <cohuck@redhat.com>]

While playing around with compat machines a bit, I noticed that my
zpci detanglement patches broke migration from 2.7 to current master
(2.8 or newer are fine, which is why I did not notice that before.)

qemu 2.7 seems to create a savevm that a s390-next (or master) build
without the s390 phb chokes on:

qemu-system-s390x: Unknown savevm section or instance 'PCIBUS' 0

Creating the s390 phb for compat machines seems to cure this; still
RFC for the following reasons:

- I'm not sure what we're supposed to do on builds without pci. Fail
  creating the compat machines? Do we need a new set of _NOPCI compat
  machines for that?
- I don't understand why 2.7 fails, but 2.8 and later are fine. At
  least, I was not able to spot which commit changed the behaviour
  here... and I really want to understand this. Pointers welcome.
- I have not tested it extensively yet.

Patch is against s390-next.

Cornelia Huck (1):
  s390x/ccw: create s390 phb for compat reasons as well

 hw/s390x/s390-virtio-ccw.c         | 6 +++++-
 include/hw/s390x/s390-virtio-ccw.h | 1 +
 2 files changed, 6 insertions(+), 1 deletion(-)

-- 
2.13.5