Merge tag 'kvm-x86-selftests-6.3' of https://github.com/kvm-x86/linux into HEAD

KVM selftests changes for 6.3:

 - Cache the CPU vendor (AMD vs. Intel) and use the info to emit the correct
   hypercall instruction instead of relying on KVM to patch in VMMCALL

 - A variety of one-off cleanups and fixes