KVM: x86/mmu: Zap SPTEs on MTRR update iff guest MTRRs are honored

When guest MTRRs are updated, zap SPTEs and do zap range calcluation if and
only if KVM's MMU is honoring guest MTRRs, which is the only time that KVM
incorporates the guest's MTRR type into the final memtype.

Suggested-by: Chao Gao <[email protected]>
Suggested-by: Sean Christopherson <[email protected]>
Cc: Kai Huang <[email protected]>
Signed-off-by: Yan Zhao <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[sean: rephrase shortlog]
Signed-off-by: Sean Christopherson <[email protected]>

Author: yanzhao56

arch/x86/kvm/mtrr.c

@@ -320,7 +320,7 @@ static void update_mtrr(struct kvm_vcpu *vcpu, u32 msr)
 	struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state;
 	gfn_t start, end;
 
-	if (!tdp_enabled || !kvm_arch_has_noncoherent_dma(vcpu->kvm))
+	if (!kvm_mmu_honors_guest_mtrrs(vcpu->kvm))
 		return;
 
 	if (!mtrr_is_enabled(mtrr_state) && msr != MSR_MTRRdefType)