diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index e4d358195e54..9a56ca2fa257 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -822,6 +822,8 @@ int __kvm_set_memory_region(struct kvm *kvm,
 		old_memslots = kvm->memslots;
 		rcu_assign_pointer(kvm->memslots, slots);
 		synchronize_srcu_expedited(&kvm->srcu);
+		/* slot was deleted or moved, clear iommu mapping */
+		kvm_iommu_unmap_pages(kvm, &old);
 		/* From this point no new shadow pages pointing to a deleted,
 		 * or moved, memslot will be created.
 		 *
@@ -837,20 +839,19 @@ int __kvm_set_memory_region(struct kvm *kvm,
 	if (r)
 		goto out_free;
 
-	/* map/unmap the pages in iommu page table */
-	if (npages) {
-		r = kvm_iommu_map_pages(kvm, &new);
-		if (r)
-			goto out_free;
-	} else
-		kvm_iommu_unmap_pages(kvm, &old);
-
 	r = -ENOMEM;
 	slots = kmemdup(kvm->memslots, sizeof(struct kvm_memslots),
 			GFP_KERNEL);
 	if (!slots)
 		goto out_free;
 
+	/* map new memory slot into the iommu */
+	if (npages) {
+		r = kvm_iommu_map_pages(kvm, &new);
+		if (r)
+			goto out_slots;
+	}
+
 	/* actual memory is freed via old in kvm_free_physmem_slot below */
 	if (!npages) {
 		new.dirty_bitmap = NULL;
@@ -869,6 +870,8 @@ int __kvm_set_memory_region(struct kvm *kvm,
 
 	return 0;
 
+out_slots:
+	kfree(slots);
 out_free:
 	kvm_free_physmem_slot(&new, &old);
 out: