diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index 9a4af880e941..6e8804fe0095 100644
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -125,6 +125,19 @@ static void vfio_release_device_set(struct vfio_device *device)
 	xa_unlock(&vfio_device_set_xa);
 }
 
+unsigned int vfio_device_set_open_count(struct vfio_device_set *dev_set)
+{
+	struct vfio_device *cur;
+	unsigned int open_count = 0;
+
+	lockdep_assert_held(&dev_set->lock);
+
+	list_for_each_entry(cur, &dev_set->device_list, dev_set_list)
+		open_count += cur->open_count;
+	return open_count;
+}
+EXPORT_SYMBOL_GPL(vfio_device_set_open_count);
+
 /*
  * Group objects - create, release, get, put, search
  */
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index e7cebeb875dd..fdd393f70b19 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -189,6 +189,7 @@ int vfio_register_emulated_iommu_dev(struct vfio_device *device);
 void vfio_unregister_group_dev(struct vfio_device *device);
 
 int vfio_assign_device_set(struct vfio_device *device, void *set_id);
+unsigned int vfio_device_set_open_count(struct vfio_device_set *dev_set);
 
 int vfio_mig_get_next_state(struct vfio_device *device,
 			    enum vfio_device_mig_state cur_fsm,