[nova] iothread support with Libvirt

Hi, I haven't found anything that indicates Nova supports adding iothreads parameters to the Libvirt XML file. I had asked various performance related questions a couple years back, including asking if iothreads were available, but I didn't get any response (so assumed the answer was no). So I'm just checking again to see if this has been a consideration to help improve a VM's storage performance - specifically with extremely high-speed storage in the host. Or is there a way to add iothread-related parameters without Nova being involved (such as modifying a template)? Thanks! Eric