virtio-iommu: Add notify_flag_changed() memory region callback

Add notify_flag_changed() to notice when memory listeners are added and
removed.

Acked-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Bharat Bhushan <bbhushan2@marvell.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Message-Id: <20201030180510.747225-7-jean-philippe@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
index 985257c..78e07aa 100644
--- a/hw/virtio/virtio-iommu.c
+++ b/hw/virtio/virtio-iommu.c
@@ -886,6 +886,19 @@
     qemu_mutex_unlock(&s->mutex);
 }
 
+static int virtio_iommu_notify_flag_changed(IOMMUMemoryRegion *iommu_mr,
+                                            IOMMUNotifierFlag old,
+                                            IOMMUNotifierFlag new,
+                                            Error **errp)
+{
+    if (old == IOMMU_NOTIFIER_NONE) {
+        trace_virtio_iommu_notify_flag_add(iommu_mr->parent_obj.name);
+    } else if (new == IOMMU_NOTIFIER_NONE) {
+        trace_virtio_iommu_notify_flag_del(iommu_mr->parent_obj.name);
+    }
+    return 0;
+}
+
 static void virtio_iommu_device_realize(DeviceState *dev, Error **errp)
 {
     VirtIODevice *vdev = VIRTIO_DEVICE(dev);
@@ -1116,6 +1129,7 @@
 
     imrc->translate = virtio_iommu_translate;
     imrc->replay = virtio_iommu_replay;
+    imrc->notify_flag_changed = virtio_iommu_notify_flag_changed;
 }
 
 static const TypeInfo virtio_iommu_info = {