Borbein (ppc64el) got kernel and libvirt-bin updates.
I have removed the new kernels. We are booted on the
old 3.19.0-66-generic that was being used last week.

Virsh is still busted. All the vms I start are paused
instead of running. I cannor resume them. I cloned a
new vm and started; it too was paused.

I see this error in /var/log/libvirt/qemu/* starting o 2016-08-25

   error: kvm run failed Device or resource busy
   This is probably because your SMT is enabled.
   VCPU can only run on primary threads with all secondary threads offline.

https://pastebin.canonical.com/169032/

I see this bug that appears to be related
    https://bugs.launchpad.net/cloud-archive/+bug/1419842

I don't really know if smt is is mis set or we need to boot with an
older kernel?

I see
    $ sudo ppc64_cpu --smt
    SMT=8