Intel UMIP KVM Support Ejected From Linux 4.15, Will Have To Wait To Linux 4.16

Intel UMIP support landed in Linux 4.15 as part of the x86 updates. User-Mode Instruction Prevention is for preventing certain instructions from being executed outside of ring level zero and will be supported by future Intel CPUs. Support for UMIP within the KVM virtualization space though will have to wait until Linux 4.16.

Submitted a few days ago were extra KVM changes for Linux 4.15 that included the Intel UMIP support on the KVM side for supporting this feature with KVM guests.

Linus had pulled in these changes but then decided to unpull it for not enough testing. Linus wrote, "So I pulled it, but then checked, None of this was in linux-next 20171117 either, So I unpulled it."

So due to not getting enough exposure via linux-next for these secondary KVM updates, they will have to wait until Linux 4.16. The KVM-side work on supporting AMD Secure Encrypted Virtualization (SEV) with EPYC CPUs also was already known for having to wait until 4.16 for additional testing while the generic SEV code has landed for 4.15.