Isolating Xwayland in a VM

In my last post, Qubes-lite with KVM and Wayland, I described setting up a QubesOS-inspired Linux system that runs applications in virtual machines. A Wayland proxy running in each VM connects its applications to the host Wayland compositor over virtwl, allowing them to appear on the desktop alongside normal host applications. In this post, I extend this to support X11 applications using Xwayland.