KVM: MMU: Allow spte.w=1 for gpte.w=0 and cr0.wp=0 only in shadow mode

When tdp is enabled, the guest's cr0.wp shouldn't have any effect on spte
permissions.

Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/mmu.c

@@ -1882,7 +1882,8 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
 	spte |= (u64)pfn << PAGE_SHIFT;
 
 	if ((pte_access & ACC_WRITE_MASK)
-	    || (write_fault && !is_write_protection(vcpu) && !user_fault)) {
+	    || (!tdp_enabled && write_fault && !is_write_protection(vcpu)
+		&& !user_fault)) {
 
 		if (level > PT_PAGE_TABLE_LEVEL &&
 		    has_wrprotected_page(vcpu->kvm, gfn, level)) {