Comment 13 for bug 1830268

Hmm, we just don't need the xenial portion.
As already mentioned at the backport the code was way different then.

I can start a VMX defined guest on Xenial:

  <cpu match='exact'>
    <model fallback='allow'>core2duo</model>
    <vendor>Intel</vendor>
    <feature policy='require' name='vmx'/>
  </cpu>

And it becomes -cpu core2duo,+vmx for qemu commandline.
So Xenial is actually "invalid" as the issue described here doesn't apply there.