KVM: MMU: Simplify kvm_mmu_zap_page()

The twisty maze of conditionals can be reduced.

[joerg: fix tlb flushing]
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

arch/x86/kvm/mmu.c

@@ -955,7 +955,6 @@ static void kvm_mmu_page_unlink_children(struct kvm *kvm,
 				rmap_remove(kvm, &pt[i]);
 			pt[i] = shadow_trap_nonpresent_pte;
 		}
-		kvm_flush_remote_tlbs(kvm);
 		return;
 	}
 
@@ -974,7 +973,6 @@ static void kvm_mmu_page_unlink_children(struct kvm *kvm,
 		}
 		pt[i] = shadow_trap_nonpresent_pte;
 	}
-	kvm_flush_remote_tlbs(kvm);
 }
 
 static void kvm_mmu_put_page(struct kvm_mmu_page *sp, u64 *parent_pte)
@@ -1016,18 +1014,16 @@ static void kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp)
 	++kvm->stat.mmu_shadow_zapped;
 	kvm_mmu_page_unlink_children(kvm, sp);
 	kvm_mmu_unlink_parents(kvm, sp);
-	if (!sp->root_count) {
-		if (!sp->role.metaphysical && !sp->role.invalid)
+	kvm_flush_remote_tlbs(kvm);
+	if (!sp->role.invalid && !sp->role.metaphysical)
 		unaccount_shadowed(kvm, sp->gfn);
+	if (!sp->root_count) {
 		hlist_del(&sp->hash_link);
 		kvm_mmu_free_page(kvm, sp);
 	} else {
-		int invalid = sp->role.invalid;
-		list_move(&sp->link, &kvm->arch.active_mmu_pages);
 		sp->role.invalid = 1;
+		list_move(&sp->link, &kvm->arch.active_mmu_pages);
 		kvm_reload_remote_mmus(kvm);
-		if (!sp->role.metaphysical && !invalid)
-			unaccount_shadowed(kvm, sp->gfn);
 	}
 	kvm_mmu_reset_last_pte_updated(kvm);
 }
@@ -1842,7 +1838,7 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
 	index = kvm_page_table_hashfn(gfn);
 	bucket = &vcpu->kvm->arch.mmu_page_hash[index];
 	hlist_for_each_entry_safe(sp, node, n, bucket, hash_link) {
-		if (sp->gfn != gfn || sp->role.metaphysical)
+		if (sp->gfn != gfn || sp->role.metaphysical || sp->role.invalid)
 			continue;
 		pte_size = sp->role.glevels == PT32_ROOT_LEVEL ? 4 : 8;
 		misaligned = (offset ^ (offset + bytes - 1)) & ~(pte_size - 1);