A number of people are working on integrating OpenBSD into Qubes.
In particular, OpenBSD's hardening and mitigations are potentially very
useful in talking to the NIC: Xen vulnerabilities have been repeatedly
found that would allow a guest with PCI access to compromise the entire
system, and on most machines the network card is a PCI device.
Additionally, wireless drivers on Linux leave some things to be desired
and the network stack is very exposed to the adversary compared to other
aspects of the system.
The limited scope of the networking VM in Qubes (it does not need much
in the way of bells and whistles, it simply talks to the NIC and passes
on data) means that it's much easier to use OpenBSD here than it would
be to use OpenBSD for e.g GUI applications.
Unfortunately, there are still significant issues (currently good
integration requires patching /etc/rc, among other things):
https://github.com/QubesOS/qubes-issues/issues/5294#issuecomment-707278609
As the commenter notes, this would be much easier if an OpenBSD
committer was interested in helping. Anyone?
