Anil gives an overview of Docker and FreeBSD as well as OpenBSD and how they interact.
Guest Support for bhyve
Illumos
MacOS
Nested Virtualization Not asked for very often and requires a lot of effort. Mostly a developer ask and the developers are not a significant enough group to make it a high priority.
9P filesystem support Not POSIX enough to work correctly? There is a VIRTIO spec.
Process Level Virtualization
Live Migration There is a snapshot and restore implementation which is up on github and is the best place to start.
Live device attach and remove
GPU Pass through Frequently requested by requires some magic, 1:1, mappings for the BAR.
SGX Support Still too new but now that we have a driver from Ruslan there is renewed interest. May be a very large piece of work to get it going. The hope is that Ruslan will look at this.
aarch64 Google SoC project a couple of years ago got bhyve going on 32 bit ARM. For 64 bit there are things that need to be updated. Supposedly a small number of lines of code need to be changed to get 64 bit working based on the current code. Andrew Turner has reviewed some of this work and is looking for the right way forwards.
Virtual IO-MMU There are proposals in the Linux world for how to do this and there is interest in how to spec this out.
Questions about Xen They are looking into new machines to boot on as the current 300 series boxes are bridked. packet.net is mentioned.