A KMS driver for the QXL virtual graphics adapter has been talked about before and even a virtual Gallium3D driver, so that the open-source Linux KVM stack with Red Hat's QXL can compete with the graphics options presented by VMware and Oracle's VirtualBox.
QEMU still doesn't have any useful guest 3D acceleration support and up to now didn't even have any good KMS driver. Previously there was the Cirrus KMS driver for QEMU, but that never ended up being merged into the Linux kernel. Fortunately, this QXL KMS driver is likely to be merged and has served as a proposed feature for Fedora.
David Airlie announced his QXL KMS driver on the dri-devel mailing list with the two patches to introduce the driver. There's also DRM library (libdrm) changes, but he may end up merging that into just the xf86-video-qxl DDX.
This KMS/DRM driver for QXL puts the open-source virtualization stack one step closer to good guest graphics support in QEMU, but there's still much work left before seeing a Gallium3D driver.