Hi,
I've encountered a problem that some of /proc/net/ files can't be accessed in unprivileged containers, because it is owned by nobody:nogroup (-1:-1) and have 440 permissions.
This exact issue was solved in LXC project by unsharing netns: https://github.com/lxc/lxc/commit/5b1e83cbc498cd3edeaf13afa987d530299a35a7 . Maybe it could be similarly fixed on libvirt-lxc?
BR,
John H.