Hi  Daniel, 

     Thanks for your help about my bug fix. Now I find that I can't delete instance with nvram. The problem is really serious for AArch64, since it always needs uefi.

     I'm now working on this bug: https://bugs.launchpad.net/ubuntu/+source/nova/+bug/1567807, it's about Nova can't delete instance which has been booted by UEFI. 

     I find that you have upload a patch in 2015:   https://www.redhat.com/archives/libvir-list/2015-February/msg00915.html , to fix libvirt don't refuse to delete instance with NVRAM. I have a question that the patch status is ? I see that your patch has not been merged. Do we need to modify the Nova code to add support to delete nvram instance? Or just wait for Libvirt to fix? Maybe I can help when we need to modify Nova.

      Thanks Daniel ~ Looking forward to your response~