managed save returns "migration with virtiofs device is not supported"

[Francesc Guasch]

Hello. I have a virtual machine with a virtiofs entry configured.

When I try to do a managed save it fails with this message:

     libvirt error code: 55, message: Requested operation is not valid:
     migration with virtiofs device is not supported

This is libvirt 8.0.0 that comes with Ubuntu 22.04. I have seen
the current release in git is libvirt 8.5 . I will try to build
from source and try again if you think this was not the expected
behaviour.

This is the filesystem entry:

<filesystem type='mount' accessmode='passthrough'>
   <driver type='virtiofs'/>
   <source dir='/home/shared'/>
   <target dir='home_shared'/>
   <address type='pci' domain='0x0000' bus='0x01' slot='0x00'
	 function='0x0'/>
</filesystem>

Sorry if this is not the right place to ask. I can write an
issue in gitlab or whatever is more appropriate.

Thanks !