What were you trying to do that didn't work?

OpenStack is trying to use mtty/mdpy for testing vfio-mdev upstream without real hardware.

Unfortunately, when testing, we see that libvirt reports 'computer' as a parent for either a mtty mdev or a mdpy mdev, which makes accounting difficult since both devices are tangled.

Please provide the package NVR for which bug is seen:

How reproducible:

Steps to reproduce

1. 1. ensure that you built and loaded the mtty kernel module
      lsmod | grep mtty

1. create two mdevs, one from mtty and the other from mdpy devices

virsh nodedev-list --cap mdev --all
mdev_378d0ce4_e771_494f_91a4_388c0e89ab39_mtty
mdev_68c2a491_9a5f_4fc4_a16a_eabfbdf6e6a9_mdpy

1. ask libvirt to give you the device XML of each, you'll see that both are having 'computer' as parent instead of 'mtty'/'mdpy'

stack@sbauza-dev2:~$ virsh nodedev-dumpxml mdev_378d0ce4_e771_494f_91a4_388c0e89ab39_mtty
<device>
  <name>mdev_378d0ce4_e771_494f_91a4_388c0e89ab39_mtty</name>
  <path>/sys/devices/virtual/mtty/mtty/378d0ce4-e771-494f-91a4-388c0e89ab39</path>
  <parent>computer</parent>
  <driver>
    <name>mtty</name>
  </driver>
  <capability type='mdev'>
    <type id='mtty-1'/>
    <uuid>378d0ce4-e771-494f-91a4-388c0e89ab39</uuid>
    <iommuGroup number='0'/>
  </capability>
</device>

stack@sbauza-dev2:~$ virsh nodedev-dumpxml mdev_68c2a491_9a5f_4fc4_a16a_eabfbdf6e6a9_mdpy
<device>
  <name>mdev_68c2a491_9a5f_4fc4_a16a_eabfbdf6e6a9_mdpy</name>
  <path>/sys/devices/virtual/mdpy/mdpy/68c2a491-9a5f-4fc4-a16a-eabfbdf6e6a9</path>
  <parent>computer</parent>
  <driver>
    <name>mdpy</name>
  </driver>
  <capability type='mdev'>
    <type id='mdpy-hd'/>
    <uuid>68c2a491-9a5f-4fc4-a16a-eabfbdf6e6a9</uuid>
    <iommuGroup number='1'/>
  </capability>
</device>

Expected results

the parent value should be 'mdpy' or 'mtty' depending on the parent device.

Actual results

it says 'computer'