Comment 5 for bug 1755153

Just freed up my test system from the verification of the next upload.
Trying to reproduce the issue ...

Starting a trivial uvt guest:
$ uvt-simplestreams-libvirt --verbose sync --source http://cloud-images.ubuntu.com/daily arch=ppc64el label=daily release=bionic
$ uvt-kvm create --password=ubuntu cpaelzer-bionic release=bionic arch=ppc64el label=daily

Then adding the potential hotplug memory (without further changes)
That is 1.5G current and 10G max in 16 slots
  <maxMemory slots='16' unit='KiB'>10485760</maxMemory>
  <memory unit='KiB'>1572864</memory>
  <currentMemory unit='KiB'>1572864</currentMemory>

Attaching the hotplug mem xml (also simplified):
<memory model='dimm'>
        <target>
                <size unit='KiB'>524288</size>
        </target>
</memory>

I can confirm the reported issue with that:
ubuntu@wichita:~$ virsh attach-device cpaelzer-bionic hp512m.xml --live
error: Failed to attach device from hp512m.xml
error: this function is not supported by the connection driver: virSecurityManagerSetMemoryLabel