"MSI-X is not supported by interrupt controller" when launching aarch64 instance on pike

[Jason Hobbs]

Attempting to launch an aarch64 nova-compute-kvm instance on pike fails with the error: "MSI-X is not supported by interrupt controller".

Longer form of the error: http://paste.ubuntu.com/26184308/

To reproduce, deploy openstack using the openstack-base bundle with juju (https://jujucharms.com/openstack-base/). This deploys on ubuntu xenial using pike packages.

Then, configure tenants/users/networks/images in openstack, including uploading a xenial cloud image to glance.

Then, try to start an instance.

Expected result is that the instance starts without errors, but the actual result is that it fails with the error above.