Virtual GEM To Increase Mesa's Software Rasterizer Performance
It's been talked about before to make a fake DRM/GEM driver to enhance the performance of Mesa's Softpipe/LLVMpipe drivers while Zach Reizner of Google has been the one taking action recently on making it a reality.
The vGEM DRM driver is a virtual GEM driver with PRIME sharing and allows vGEM to import a GEM object from other drivers to mmap them to user-space. This virtual graphics memory manager can be used by Mesa's software rasterizer for enhanced performance.
dri-devel list. Hopefully vGEM will get ready for merging into an upcoming Linux kernel release to benefit those running (or just testing) on the software rasterizer.