While VirtualBox and VMware right now support 3D/OpenGL acceleration by passing the graphics commands onto the host machine for processing, QEMU/KVM does not but it's (hopefully) going to be changed soon by Red Hat. After a Gallium3D SPICE driver was long talked about, there's finally action happening per my posting a few days ago.
Airlie's posting came after an Oracle engineer talked about writing a Mesa driver for VirtualBox. At that time, David Airlie of Red Hat talked about how he was working on a Gallium3D driver for passing the graphics commands from a VM onto the host through QEMU for then executing on the host's hardware.
In a new mailing list post, David now says:
Red Hat is currently just letting me do the research on what a possible 3D [virtualization] solution for [QEMU] might look like and I'll probably make some sort of announcement in a few weeks if I get it to run gnome-shell smoothly, and not upside down. So you can use the code and if you want to make some of it shared I'm happy to contribute to something common. I've pushed a few fixes to the shader code over the last few days now that I have some piglit coverage.So with a bit of luck in a few weeks we will hopefully have some good news to pass along... With more Linux desktops requiring OpenGL support, this is certainly good news for QEMU/KVM to take on the competition from VMware and Oracle VM VirtualBox.