On Fri, Aug 29, 2014 at 07:22:18PM +0200, Benoît Canet wrote:
> Listening at Palo's suggestion I started discussing privately with
> Andy about integrating LIO and the QEMU block layer together using
> tcmu-runner: https://github.com/agrover/tcmu-runner.

I looked at this briefly when Andy posted the userspace target patches
to the target-devel list.

The easiest approach is to write a tool similar to qemu-nbd that speaks
the userspace target protocol (i.e. mmap the shared memory).

If the tcmu setup code is involved, maybe providing a libtcmu with the
setup code would be useful.  I suspect that other projects may want to
integrate userspace target support too.  It's easier to let people add
it to their codebase rather than hope they bring their codebase into
tcmu-runner.

The qemu-lio tool would live in the QEMU codebase and reuse all the
infrastructure.  For example, it could include a QMP monitor just like
the one you are adding to qemu-nbd.

Stefan