Keith Packard's Work On Better Supporting VR HMDs Under Linux With X.Org/DRM
A big part of this work is the concept of DRM leases, a new Vulkan extension, and other changes to the stack.
If you are looking for an overview of his current design approach, the video of his presentation at this week's XDC2017 is embedded below where he goes over the work. There's also the PDF slide deck.
There are Linux kernel, X.Org Server, RandR protocol, XCB, libdrm, and Mesa changes all needed for the DRM leasing concept that are all currently out of mainline. It will likely be well into 2018 before all of this is properly handled and easily available on the Linux desktop.