For kicks, I wrote this program that uses libtracefs to search all CIDS
(1-255), and find the kvm guests that are attached to them.

It traces the sched_wakeup and kvm_exit, looking for:

 this_task -> wakeup -> wakeup -> kvm_exit

when doing a connect to a cid.

When it finds the pid that did a kvm_exit, it knows that's the PID that
is woken by the vhost worker task. It's a little slow, and I would
really like a better way to do this, but it's at least an option that
is available now.

-- Steve