[arm64][libvirt] firmware metadata files not found for arm64 on ubuntu 18.04

[Rico Lin]

From devstack arm64 job patch [1], I found this error [2][3] when using bionic images on arm64 environment:

Failed to build and run instance: nova.exception.InternalError: Failed to locate firmware descriptor files
Traceback (most recent call last):
  File "/opt/stack/nova/nova/compute/manager.py", line 2393, in _build_and_run_instance
    accel_info=accel_info)
  File "/opt/stack/nova/nova/virt/libvirt/driver.py", line 3880, in spawn
    mdevs=mdevs, accel_info=accel_info)
  File "/opt/stack/nova/nova/virt/libvirt/driver.py", line 6723, in _get_guest_xml
    context, mdevs, accel_info)
  File "/opt/stack/nova/nova/virt/libvirt/driver.py", line 6334, in _get_guest_config
    self._configure_guest_by_virt_type(guest, instance, image_meta, flavor)
  File "/opt/stack/nova/nova/virt/libvirt/driver.py", line 5945, in _configure_guest_by_virt_type
    has_secure_boot=guest.os_loader_secure)
  File "/opt/stack/nova/nova/virt/libvirt/host.py", line 1636, in get_loader
    for loader in self.loaders:
  File "/opt/stack/nova/nova/virt/libvirt/host.py", line 1619, in loaders
    self._loaders = _get_loaders()
  File "/opt/stack/nova/nova/virt/libvirt/host.py", line 102, in _get_loaders
    raise exception.InternalError(msg)
nova.exception.InternalError: Failed to locate firmware descriptor files

As I move [1] to use the focal version, this error message disappeared.
The wired part is I do can locate firmware descriptor files on my AWS bionic arm64 test environment right at the same demanded path. So I'm not sure what exactly happened there

[1] https://review.opendev.org/c/openstack/devstack/+/708317

[2] https://zuul.opendev.org/t/openstack/build/77b0d998c9f14e1b859467016dfb7852/log/controller/logs/screen-n-cpu.txt#9821
[3] http://paste.openstack.org/show/803786/

[Balazs Gibizer (balazs-gibizer)]

On master we are move from Bionic to Focal. As you reported this does not happen on Focal. Is this issue affecting one of our stable branches where we still have Bionic? I looked at [1] and I don't see this job running on stable branches.

I mark this Incomplete. If you can state which branch it affected then please set it back to New.

[1] https://zuul.opendev.org/t/openstack/builds?job_name=devstack-platform-arm64&project=openstack/devstack

[Launchpad Janitor (janitor)]

[Expired for OpenStack Compute (nova) because there has been no activity for 60 days.]