any primer on running bhyve guests sharing disk with host ?

Hi,
in order to do some kernel testing, I would like to run bhyve guests
using (through NFS, probably) the host's file system.
diskless(8) is probably one way to go, i was wondering if
someone has instructions for that.
Specifically:
- how to "bhyveload" a kernel (rather than the full disk image);
  as an alternative, given a kernel, something to build an image
  that can be passed to bhyveload

- how to pass the necessary config (rootpath) to the client
  without having to rely on a specialized dhcp server

I used to be familiar with diskless configs, so i can probably sort
out the server side myself.

	cheers
	luigi