I know it's possible to create a 9p fs shared between guest and host. It would be awesome if we could automate the creation+reuse of such a fs when used with the -i flag.

@nathanchance also mentioned https://virtio-fs.gitlab.io/. If that works, then let's use that; the ends are more important to me than the means (so I don't care whether we ultimately use 9p or virtiofs). I'd like to be able to copy coverage and profile data out of a guest back to a host.