Looks like we are narrowing this down to a virtio device with no serial number. On a bionic host, if I manually add a serial number to the virtio device (in virt-manager, just before starting the installation, for example) then this works.
Looks like we are narrowing this down to a virtio device with no serial number. On a bionic host, if I manually add a serial number to the virtio device (in virt-manager, just before starting the installation, for example) then this works.