Your statement about how the kernel only mediates access to the GPU is exactly right. GPU drivers have long followed an "exokernel" approach: the kernel just en

Your statement about how the kernel only mediates access to the GPU is exactly right. GPU drivers have long followed an "exokernel" approach: the kernel just ensures that access to the hardware is multiplexed with enforced security boundaries, everything else -- the actual abstracting over hardware differences -- is done by userspace libraries. It's somewhat amusing to me that the people who discuss exokernels rarely talk about GPUs, even though that's the one area of computing where exokernel ideas are universally deployed today.