v4.19.13 snapshot.
diff --git a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c
new file mode 100644
index 0000000..6f0391f
--- /dev/null
+++ b/drivers/vfio/mdev/mdev_driver.c
@@ -0,0 +1,119 @@
+/*
+ * MDEV driver
+ *
+ * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+ * Author: Neo Jia <cjia@nvidia.com>
+ * Kirti Wankhede <kwankhede@nvidia.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/device.h>
+#include <linux/iommu.h>
+#include <linux/mdev.h>
+
+#include "mdev_private.h"
+
+static int mdev_attach_iommu(struct mdev_device *mdev)
+{
+ int ret;
+ struct iommu_group *group;
+
+ group = iommu_group_alloc();
+ if (IS_ERR(group))
+ return PTR_ERR(group);
+
+ ret = iommu_group_add_device(group, &mdev->dev);
+ if (!ret)
+ dev_info(&mdev->dev, "MDEV: group_id = %d\n",
+ iommu_group_id(group));
+
+ iommu_group_put(group);
+ return ret;
+}
+
+static void mdev_detach_iommu(struct mdev_device *mdev)
+{
+ iommu_group_remove_device(&mdev->dev);
+ dev_info(&mdev->dev, "MDEV: detaching iommu\n");
+}
+
+static int mdev_probe(struct device *dev)
+{
+ struct mdev_driver *drv = to_mdev_driver(dev->driver);
+ struct mdev_device *mdev = to_mdev_device(dev);
+ int ret;
+
+ ret = mdev_attach_iommu(mdev);
+ if (ret)
+ return ret;
+
+ if (drv && drv->probe) {
+ ret = drv->probe(dev);
+ if (ret)
+ mdev_detach_iommu(mdev);
+ }
+
+ return ret;
+}
+
+static int mdev_remove(struct device *dev)
+{
+ struct mdev_driver *drv = to_mdev_driver(dev->driver);
+ struct mdev_device *mdev = to_mdev_device(dev);
+
+ if (drv && drv->remove)
+ drv->remove(dev);
+
+ mdev_detach_iommu(mdev);
+
+ return 0;
+}
+
+struct bus_type mdev_bus_type = {
+ .name = "mdev",
+ .probe = mdev_probe,
+ .remove = mdev_remove,
+};
+EXPORT_SYMBOL_GPL(mdev_bus_type);
+
+/**
+ * mdev_register_driver - register a new MDEV driver
+ * @drv: the driver to register
+ * @owner: module owner of driver to be registered
+ *
+ * Returns a negative value on error, otherwise 0.
+ **/
+int mdev_register_driver(struct mdev_driver *drv, struct module *owner)
+{
+ /* initialize common driver fields */
+ drv->driver.name = drv->name;
+ drv->driver.bus = &mdev_bus_type;
+ drv->driver.owner = owner;
+
+ /* register with core */
+ return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL(mdev_register_driver);
+
+/*
+ * mdev_unregister_driver - unregister MDEV driver
+ * @drv: the driver to unregister
+ */
+void mdev_unregister_driver(struct mdev_driver *drv)
+{
+ driver_unregister(&drv->driver);
+}
+EXPORT_SYMBOL(mdev_unregister_driver);
+
+int mdev_bus_register(void)
+{
+ return bus_register(&mdev_bus_type);
+}
+
+void mdev_bus_unregister(void)
+{
+ bus_unregister(&mdev_bus_type);
+}