David Airlie has provided an update this week at Linux.Conf.Au on his VirtIO GPU support for having guest OpenGL acceleration within Linux KVM/QEMU virtual machines.
For months now David has been working on Virgil3D
for finally being able to offer 3D guest VM acceleration support
while VirtualBox and VMware virtualization solutions have already been offering this pass-through 2D/3D support for years.
For those interested in an update on Virgil3D, David Airlie talked about it at LCA 2014 yesterday in Australia. The video recording of his talk can be found at linux.org.au
(MP4 file). I don't yet have any notes on the VirtIO GPU update since I'm still travelling and haven't had a chance to watch the video yet.