Hello,
Why LIBVIRT software/libs need to chown "near the root level" (home/blahblah/) when raw/vdi/vhd can contains lots of directories as /home/user/Virtual_HDs/desktop/daddy/private/bedroom/number2/hd.vdi ?
on ubuntu, "/media/hostname" can contains all our external HD's without relation with virtualization !!! :-(
another sample picked up in the net:
WARNING /home/jwright/virtualMachines/images/fedora25.qcow2 may not be
accessible by the hypervisor. You will need to grant the 'qemu' user
search permissions for the following directories: ['/home/jwright']