qemu: virtio fails with version 2.5 on ppc64el (slof update needed)

[Samuel Gauthier]

Virtio interfaces are not detected correctly when booting a cloud image with mitaka qemu-2.5 on ppc64el.

Reproduction
============

First, I installed mitaka's ppc qemu.

# apt-get install software-properties-common
# add-apt-repository cloud-archive:mitaka
# apt-get update
# apt-get install qemu-system qemu qemu-slof qemu-system-ppc

I disabled hyperthreading on the ppc64 cores to be able to boot vms (as stated here: https://wiki.ubuntu.com/ppc64el/CommonQuestions#How_to_use_Ubuntu_as_a_hypervisor.3F)

# ppc64_cpu --smt=off

I then tried to boot the ppc64el ubuntu cloud image.

Qemu tells that "64-bit PCI space not supported yet!". Virtio interfaces fail to be detected.

# /usr/bin/qemu-system-ppc64le -k fr --enable-kvm -m 512 -smp 4 -device virtio-net,mac=de:ad:de:01:02:03,netdev=user.0,addr=03 -netdev user,id=user.0 -hda "./trusty-server-cloudimg-ppc64el-disk1.img" -snapshot -nographic
SLOF **********************************************************************
QEMU Starting
Build Date = Jan 28 2015 21:06:32
FW Version = buildd@ release 20140630
Press "s" to enter Open Firmware.

Populating /vdevice methods
Populating /vdevice/vty@71000000
Populating /vdevice/nvram@71000001
Populating /vdevice/v-scsi@71000002
SCSI: Looking for devices
8000000000000000 DISK : "QEMU QEMU HARDDISK 2.5+"
8200000000000000 CD-ROM : "QEMU QEMU CD-ROM 2.5+"
Populating /pci@800000020000000

Warning: 64-bit PCI space not supported yet! 100000000 10120000000
Adapters on 0800000020000000
00 0000 (D) : 1234 1111 qemu vga
00 0800 (D) : 106b 003f serial bus [ usb-ohci ]
00 1800 (D) : 1af4 1000 virtio [ net ]
No NVRAM common partition, re-initializing...
Installing QEMU fb
(...)
[ 0.294288] virtio-pci: probe of 0000:00:03.0 failed with error -12
(...)
Cloud-init v. 0.7.5 running 'init' at Fri, 08 Apr 2016 09:21:00 +0000. Up 132.57 seconds.
ci-info: +++++++++++++++++++Net device info++++++++++++++++++++
ci-info: +--------+------+-----------+-----------+------------+
ci-info: | Device | Up | Address | Mask | Hw-Address |
ci-info: +--------+------+-----------+-----------+------------+
ci-info: | lo | True | 127.0.0.1 | 255.0.0.0 | . |
ci-info: +--------+------+-----------+-----------+------------+

Workaround
==========

Installing the qemu-slof version generated for Xenial fixes the problem.

# wget http://launchpadlibrarian.net/235682819/qemu-slof_20151103+dfsg-1ubuntu1_all.deb
# dpkg -i qemu-slof_20151103+dfsg-1ubuntu1_all.deb
# /usr/bin/qemu-system-ppc64le -k fr --enable-kvm -m 512 -smp 4 -device virtio-net,mac=de:ad:de:01:02:03,netdev=user.0,addr=03 -netdev user,id=user.0 -hda "./trusty-server-cloudimg-ppc64el-disk1.img" -snapshot -nographic
SLOF **********************************************************************
QEMU Starting
Build Date = Jan 29 2016 18:58:37
FW Version = buildd@ release 20151103
Press "s" to enter Open Firmware.

Populating /vdevice methods
Populating /vdevice/vty@71000000
Populating /vdevice/nvram@71000001
Populating /vdevice/v-scsi@71000002
SCSI: Looking for devices
8000000000000000 DISK : "QEMU QEMU HARDDISK 2.5+"
8200000000000000 CD-ROM : "QEMU QEMU CD-ROM 2.5+"
Populating /pci@800000020000000
00 1800 (D) : 1af4 1000 virtio [ net ]
00 0800 (D) : 106b 003f serial bus [ usb-ohci ]
00 0000 (D) : 1234 1111 qemu vga
No NVRAM common partition, re-initializing...
Installing QEMU fb
(...)
Cloud-init v. 0.7.5 running 'init' at Fri, 08 Apr 2016 09:33:48 +0000. Up 3.35 seconds.
ci-info: +++++++++++++++++++++++++Net device info+++++++++++++++++++++++++
ci-info: +--------+------+-----------+---------------+-------------------+
ci-info: | Device | Up | Address | Mask | Hw-Address |
ci-info: +--------+------+-----------+---------------+-------------------+
ci-info: | lo | True | 127.0.0.1 | 255.0.0.0 | . |
ci-info: | eth0 | True | 10.0.2.15 | 255.255.255.0 | de:ad:de:01:02:03 |
ci-info: +--------+------+-----------+---------------+-------------------+

I think that an update of qemu-slof in the mitaka's cloud-archive is needed, as it was done in Xenial here:
https://bugs.launchpad.net/ubuntu/+source/slof/+bug/1539646

[James Page (james-page)]

Backporting this package to the UCA Is somewhat tricky as it required a powerpc architecture builder, which we don't enable for the cloud archive....

I'll chat with the foundations team and see what we can do.

[Breno Leitão (breno-leitao)]

I am wondering if we should make qemu dependent on certain qemu-slo version, in order to avoid this problem.

I think that just depending on qemu-slof might cause this problem every time that qemu package is being 'imported" into cloud archive.

[James Page (james-page)]

 slof (20151103+dfsg-1ubuntu1~cloud0) trusty-mitaka; urgency=medium
 .
   * New package for the Ubuntu Cloud Archive.
 .
 slof (20151103+dfsg-1ubuntu1) xenial; urgency=low
 .
   * Merge from Debian unstable. Remaining changes:
     - Support building using a cross-compiler.
   * Add XS-Build-Indep-Architecture: powerpc to debian/control as well, so
     that we build on powerpc in Launchpad and don't need the cross-compiler
     by default (making this upstreamable to Debian).
   * Since the package can now be cross- or natively-built, and there is no
     package that provides gcc-powerpc-linux-gnu on powerpc, drop this
     build-dependency. Those who are cross-building will just need to install
     the cross-compiler by hand.