The length of time this situation has persisted has started to make me wonder. I wonder if for Nvidia it's really about making sure the consumer cards don't work on VMware and the other commercial hypervisors. I'd figure they're protecting their enterprise sales, and my guess is KVM and Xen don't have much enterprise market share, Amazon possibly notwithstanding. So if these cards run on KVM, maybe they don't care.

Still, I personally would be reluctant to drop big money on a consumer Nvidia card thinking that I'd always have the ability to use it under KVM with the latest driver. Nvidia could choose to close this particular hole at any time.