Not to tangent (top post), but ...
This is where I leverage NetworkManager in general (and have a set of standard nmcli commands and Ansible tooling for common scenarios) ... _avoiding_ libvirtd altogether. I'm even debating about taking away the default 192.168.122/24 NAT subnet as standard in new builds with QEMU/KVM installed, just because of past issues with pre/post routing, or even IP address range conflicts (long story). It's easy to overlook those as well.
YMMV, including with oVirt.
I feel like I'm taking crazy pills! I'm reading the libvirt network XML
format documentation[1], and I can't figure out how to create a simple
bridged network - no NAT, no routing, no OVS, no macvtap, etc. I.e.,
just a Linux bridge with a single physical interface attached.
None of the 3 scenarios listed for <forward mode='bridge'> describe the
simple setup that I'm trying to create, so it looks like I'll need to
create the bridge separately. (It's not hard to do, it just seems like
such a weird gap the in the functionality.)
[1] https://libvirt.org/formatnetwork.html