Comment 4 for bug 1832248

I was able to reproduce on a devstack bionic:
local.conf:TARGET_BRANCH=stable/ussuri
nova-cpu.conf:[libvirt]\hw_machine_type = x86_64=q35

And comment out os-brick patch workaround:
/usr/local/lib/python3.8/dist-packages/os_brick/initiator/linuxscsi.py:
602 #if use_multipath:
603 if True:

bionic comes with 3 qemu release:
1:4.0+dfsg-0ubuntu9.8~cloud0
1:2.11+dfsg-1ubuntu7.32
1:2.11+dfsg-1ubuntu7
test is failling with all 3 releases.

while bisecting qemu from 4.0 to 4.2.1 it start to work
with this commit:

2841ab435bca9f102311e01bf157d5fa878935dc is the first bad commit
commit 2841ab435bca9f102311e01bf157d5fa878935dc
Author: Michael S. Tsirkin <email address hidden>
Date: Fri Jun 21 00:12:22 2019 -0400

 pcie: check that slt ctrl changed before deleting

 During boot, linux would sometimes overwrites control of a powered off
 slot before powering it on. Unfortunately QEMU interprets that as a
 power off request and ejects the device.
....

~/qemu$ git branch -a --contains 2841ab435bca9f102311e01bf157d5fa878935dc
  master
  remotes/origin/master
  remotes/origin/stable-4.1
  remotes/origin/stable-4.2
  remotes/origin/stable-5.0

That's why it is fixed since focal (qemu-4.2.3)