How can I run a nested accelerated xserver? I've tried using Xephyr, including using the -fakexa but nothing seems to work. I also tried xnest, but xephyr was intended to be it's replacement and it too doesn't offer acceleration.
For Xephyr, it appears like work was done in the past to have xephyr support acceleration. It seems this work was never mainlined and/or no longer compiles against the current codebase.
Note that although I'm asking about xserver, I would be happy to hear about wayland, mir or whatever else that is capable of running nested with acceleration.