Raghav Gururajan <rvgn@disroot.org> writes:

> libvirt.libvirtError: Unable to read from
> '/sys/fs/cgroup/unified/machine/cgroup.controllers': No such file or
> directory

So, I've experienced this too. Even though this is a cgroup thing, I'm
pretty sure this isn't an issue with Linux.

I've tried reverting the changes in [1], and that seems to solve the
issue. Unfortunately, I don't have any insight in to what's different
between the problematic 5.5.0 release, and the working 5.4.0 release.

1: 458fe419232844d2021608d20dcd8f6e095eb2b4
https://git.savannah.gnu.org/cgit/guix.git/commit/?id=458fe419232844d2021608d20dcd8f6e095eb2b4