[PATCH v4 08/30] KVM: x86/mmu: Check for !leaf=>leaf, not PFN change, in TDP MMU SP removal

[Paolo Bonzini <pbonzini@xxxxxxxxxx>]

From: Sean Christopherson <seanjc@xxxxxxxxxx>

Look for a !leaf=>leaf conversion instead of a PFN change when checking
if a SPTE change removed a TDP MMU shadow page.  Convert the PFN check
into a WARN, as KVM should never change the PFN of a shadow page (except
when its being zapped or replaced).