kernel crash kvm guest on power8

subject is extremely vague, I'll give all the information I have here.
We've got a number of kvm guests running on a power8 host:

$ head -n 5 /proc/cpuinfo
processor : 0
cpu : POWER8E (raw), altivec supported
clock : 4116.000000MHz
revision : 2.0 (pvr 004b 0200)

$ rpm -qf `which qemu-system-ppc64`
qemu-system-ppc-1.6.0-2.pkvm2_1.9.2.ppc64

$ uname -r
3.10.23-900.pkvm2_1.1.ppc64

$ ps axw | grep [s]tilson-01
 83440 pts/1 S+ 0:00 /bin/bash /home/shared/bin/guest-start stilson-01
 83459 pts/1 Sl+ 4882:24 qemu-system-ppc64 -enable-kvm -M pseries -cpu host -smp cores=2,threads=1 -m 8G -net nic,macaddr=52:54:00:00:43:81 -net tap,script=no,downscript=no,ifname=tap4381 -device spapr-vscsi -drive file=/var/lib/libvirt/images/shared/stilson-01/disk1.img -drive file=/var/lib/libvirt/images/shared/stilson-01/eph0.img -nographic -vga none

The ppc64el Ubuntu 14.04 guest was found dead, and showed on console:

[708665.375169] Unable to handle kernel paging request for data at address 0x00bf0000
[708665.375321] Faulting instruction address: 0xc0000000004b790c
[708665.375388] Oops: Kernel access of bad area, sig: 11 [#1]
[708665.375440] SMP NR_CPUS=2048 NUMA pSeries
[708665.375513] Modules linked in: 8021q garp mrp ebtable_broute ebtable_filter sunrpc nfnetlink_queue nfnetlink_log nfnetlink btrfs raid6_pq xor ufs msdos xfs libcrc32c veth xt_conntrack ipt_REJECT ip6table_filter ip6_tables ebtable_nat ebtables xt_CHECKSUM iptable_mangle ipt_MASQUERADE iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack xt_tcpudp bridge stp llc iptable_filter ip_tables x_tables dm_crypt
[708665.376496] CPU: 0 PID: 270 Comm: cgmanager Not tainted 3.13.0-32-generic #57-Ubuntu
[708665.376644] task: c0000001fa55be10 ti: c0000001f8d68000 task.ti: c0000001f8d68000
[708665.376786] NIP: c0000000004b790c LR: c0000000004b78d8 CTR: c0000000004b7860
[708665.376931] REGS: c0000001f8d6b680 TRAP: 0300 Not tainted (3.13.0-32-generic)
[708665.377084] MSR: 8000000000009033 <SF,EE,ME,IR,DR,RI,LE> CR: 42008484 XER: 20000000
[708665.377411] CFAR: c00000000000a86c DAR: 0000000000bf0000 DSISR: 40000000 SOFTE: 0
GPR00: c0000000004b4710 c0000001f8d6b900 c00000000164edb8 0000000000000000
GPR04: 0000000000000800 0000000000000000 0000000000000000 0000000000000000
GPR08: 0000000000000003 0000000000bf0000 0000000000bf0000 c0000000000172a0
GPR12: 0000000022002482 c00000000fe40000 fffffffffffffe80 fffffffffffffe90
GPR16: fffffffffffffea0 fffffffffffffeb0 fffffffffffffec0 0000000000000000
GPR20: 0000010003df8420 c0000000b1bfbe00 0000000000000400 0000000000000000
GPR24: 0000000000000001 c0000000015f2ed8 0000000000000000 c0000000b1bfbdc0
GPR28: c0000000016e4c80 c0000000016e4fc4 c0000000078e6600 c0000001f8d6b9d0
[708665.379401] NIP [c0000000004b790c] .tg_prfill_cpu_rwstat+0xac/0x180
[708665.379517] LR [c0000000004b78d8] .tg_prfill_cpu_rwstat+0x78/0x180
[708665.379643] Call Trace:
[708665.379694] [c0000001f8d6b900] [c000000130138e18] 0xc000000130138e18 (unreliable)
[708665.379854] [c0000001f8d6ba20] [c0000000004b4710] .blkcg_print_blkgs+0xf0/0x1b0
[708665.380026] [c0000001f8d6bae0] [c0000000004b7730] .tg_print_cpu_rwstat+0x50/0x80
[708665.380204] [c0000001f8d6bb70] [c0000000001381ec] .cgroup_seqfile_show+0x9c/0xc0
[708665.380384] [c0000001f8d6bc00] [c000000000287e98] .seq_read+0x158/0x570
[708665.380526] [c0000001f8d6bcf0] [c0000000002560d4] .vfs_read+0xc4/0x1f0
[708665.380679] [c0000001f8d6bd90] [c000000000256ef4] .SyS_read+0x64/0xe0
[708665.380811] [c0000001f8d6be30] [c00000000000a158] syscall_exit+0x0/0x98
[708665.380956] Instruction dump:
[708665.381040] 813d0000 3be100d0 7c6307b4 7f891800 409d00b0 3d420009 392a1ca8 786a1f24
[708665.381268] 7d49502a e93e01c8 7d495214 7d2ad214 <7cead02a> e9090008 e9490010 e9290018
[708665.381505] ---[ end trace 512b8ac8f55926fd ]---
[708665.387710]

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.13.0-32-generic 3.13.0-32.57
ProcVersionSignature: User Name 3.13.0-32.57-generic 3.13.11.4
Uname: Linux 3.13.0-32-generic ppc64le
AlsaDevices: Error: command ['ls', '-l', '/dev/snd/'] failed with exit code 2: ls: cannot access /dev/snd/: No such file or directory
AplayDevices: Error: [Errno 2] No such file or directory: 'aplay'
ApportVersion: 2.14.1-0ubuntu3.2
Architecture: ppc64el
ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord'
CRDA: Error: [Errno 2] No such file or directory: 'iw'
Date: Thu Jul 31 14:32:40 2014
Lspci:

Lsusb: Error: command ['lsusb'] failed with exit code 1: unable to initialize libusb: -99
PciMultimedia:

ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcFB:

ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinux-3.13.0-32-generic root=UUID=44b83b05-4fa2-4d3f-b3af-4c8a4d097f90 ro console=hvc0 earlyprintk
RelatedPackageVersions:
 linux-restricted-modules-3.13.0-32-generic N/A
 linux-backports-modules-3.13.0-32-generic N/A
 linux-firmware N/A
RfKill: Error: [Errno 2] No such file or directory: 'rfkill'
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)