I contacted the people behind the the Fedora Seure Boot feature and got
the following responses, from Peter Jones:
Okay, to be honest I don't remember much about Xen's layout - dom0 is the
management kernel the hypervisor starts? So, depending on how xen works,
are probably more things that need to be done in the hypervisor than in
kernel, because the hypervisor is the part that does most physical memory
accesses, and that's where there's a worry about faking SB=0 and launching
At the very least, the hypervisor will a) need to be an efi binary, and b)
need to be signed with the fedora kernel-signing key. It may also need to
audited for any command line options that allow physical memory access or
other similar things, analogous to Matthew's kernel patch for linux.
We're still working out with rel-eng how getting things signed with that
going to work. I don't think there's really any necessity that it's
in a proper Feature, but if you feel like going that way, that's fine too.
and from Matthew Garrett:
Right. We can conceivably sign Xen as long as it's an EFI binary, but
I'd expect that it would have to enforce secure boot itself using the
So we need to get xen working with EFI, to lock xen down so it can't be
used to get around Secure Boot, and probably need to do some enforcement
of secure boot as well.
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