In a vacuum, I 100% agree that guest_role is better than cpu_role or vcpu_role,
but the term "guest" has already been claimed for "L2" in far too many places.
While we're behind the bikeshed... the resulting:
union kvm_mmu_role cpu_role;
union kvm_mmu_page_role mmu_role;
is a mess. Again, I really like "mmu_role" in a vacuum, but juxtaposed with
union kvm_mmu_role cpu_role;
it's super confusing, e.g. I expected
union kvm_mmu_role mmu_role;