Virtiofs xattr options on domain xml

[ksobrenat32]

Hi!

I have a debian 11 (bullseye) machine running libvirtd version 7.0.0 and 
a RHEL 9 virtual machine that I need to share a disk and though about 
virtiofs.

The disk is a btrfs disk and I have successfully mount it with:

     <filesystem type='mount' accessmode='passthrough'>
       <driver type='virtiofs' queue='1024'/>
       <binary path='/usr/lib/qemu/virtiofsd' xattr='on'>
         <cache mode='always'/>
         <lock posix='on' flock='on'/>
       </binary>
       <source dir='/mnt/WD-Disk'/>
       <target dir='media'/>
       <alias name='fs0'/>
       <address type='pci' domain='0x0000' bus='0x07' slot='0x00' 
function='0x0'/>
     </filesystem>

The problem I have is with selinux, when I try to change the context of 
a file inside the virtual machine I get a 'Operation not permitted' 
error, I can change the context in the Debian host and see the changes 
in the virtual machine but I would want to be able to change the context 
from the vm to able to use podman containers with selinux enabled.

I see on the docs 
https://qemu.readthedocs.io/en/latest/tools/virtiofsd.html#selinux-support 
you can run virtiofsd with a xattr option so it is compatible with 
selinux but I do not find a way to change the domain xml to add this 
option, is there a way to add this option? Does a better option exists 
(maybe on the guest side)?