It required quite a bit of trial and error because the components aren't very well documented and don't seem to be made for each other. I meant to publish something about it but never got around to it.
It'll likely be a lot of work to get going, but it might contain some valuable hints that I had to search for through mailing lists and reading the QEMU source. I remember needing a semi-custom kernel (maybe) and (I think) the rust version of virtiofsd.