vfio: clean up the check for mediated device in vfio_iommu_type1

Pass the group flags to ->attach_group and remove the messy check for
the bus type.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20210924155705.4258-12-hch@lst.deSigned-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/vfio.c

@@ -68,30 +68,6 @@ struct vfio_unbound_dev {
 	struct list_head		unbound_next;
 };
 
-enum vfio_group_type {
-	/*
-	 * Physical device with IOMMU backing.
-	 */
-	VFIO_IOMMU,
-
-	/*
-	 * Virtual device without IOMMU backing. The VFIO core fakes up an
-	 * iommu_group as the iommu_group sysfs interface is part of the
-	 * userspace ABI.  The user of these devices must not be able to
-	 * directly trigger unmediated DMA.
-	 */
-	VFIO_EMULATED_IOMMU,
-
-	/*
-	 * Physical device without IOMMU backing. The VFIO core fakes up an
-	 * iommu_group as the iommu_group sysfs interface is part of the
-	 * userspace ABI.  Users can trigger unmediated DMA by the device,
-	 * usage is highly dangerous, requires an explicit opt-in and will
-	 * taint the kernel.
-	 */
-	VFIO_NO_IOMMU,
-};
-
 struct vfio_group {
 	struct kref			kref;
 	int				minor;
@@ -219,7 +195,7 @@ static long vfio_noiommu_ioctl(void *iommu_data,
 }
 
 static int vfio_noiommu_attach_group(void *iommu_data,
-				     struct iommu_group *iommu_group)
+		struct iommu_group *iommu_group, enum vfio_group_type type)
 {
 	return 0;
 }
@@ -1129,7 +1105,8 @@ static int __vfio_container_attach_groups(struct vfio_container *container,
 	int ret = -ENODEV;
 
 	list_for_each_entry(group, &container->group_list, container_next) {
-		ret = driver->ops->attach_group(data, group->iommu_group);
+		ret = driver->ops->attach_group(data, group->iommu_group,
+						group->type);
 		if (ret)
 			goto unwind;
 	}
@@ -1387,7 +1364,8 @@ static int vfio_group_set_container(struct vfio_group *group, int container_fd)
 	driver = container->iommu_driver;
 	if (driver) {
 		ret = driver->ops->attach_group(container->iommu_data,
-						group->iommu_group);
+						group->iommu_group,
+						group->type);
 		if (ret)
 			goto unlock_out;
 	}

drivers/vfio/vfio.h

@@ -4,6 +4,30 @@
  *     Author: Alex Williamson <alex.williamson@redhat.com>
  */
 
+enum vfio_group_type {
+	/*
+	 * Physical device with IOMMU backing.
+	 */
+	VFIO_IOMMU,
+
+	/*
+	 * Virtual device without IOMMU backing. The VFIO core fakes up an
+	 * iommu_group as the iommu_group sysfs interface is part of the
+	 * userspace ABI.  The user of these devices must not be able to
+	 * directly trigger unmediated DMA.
+	 */
+	VFIO_EMULATED_IOMMU,
+
+	/*
+	 * Physical device without IOMMU backing. The VFIO core fakes up an
+	 * iommu_group as the iommu_group sysfs interface is part of the
+	 * userspace ABI.  Users can trigger unmediated DMA by the device,
+	 * usage is highly dangerous, requires an explicit opt-in and will
+	 * taint the kernel.
+	 */
+	VFIO_NO_IOMMU,
+};
+
 /* events for the backend driver notify callback */
 enum vfio_iommu_notify_type {
 	VFIO_IOMMU_CONTAINER_CLOSE = 0,
@@ -20,7 +44,8 @@ struct vfio_iommu_driver_ops {
 	long		(*ioctl)(void *iommu_data, unsigned int cmd,
 				 unsigned long arg);
 	int		(*attach_group)(void *iommu_data,
-					struct iommu_group *group);
+					struct iommu_group *group,
+					enum vfio_group_type);
 	void		(*detach_group)(void *iommu_data,
 					struct iommu_group *group);
 	int		(*pin_pages)(void *iommu_data,

drivers/vfio/vfio_iommu_spapr_tce.c

@@ -1239,7 +1239,7 @@ static long tce_iommu_take_ownership_ddw(struct tce_container *container,
 }
 
 static int tce_iommu_attach_group(void *iommu_data,
-		struct iommu_group *iommu_group)
+		struct iommu_group *iommu_group, enum vfio_group_type type)
 {
 	int ret = 0;
 	struct tce_container *container = iommu_data;

drivers/vfio/vfio_iommu_type1.c

@@ -36,7 +36,6 @@
 #include <linux/uaccess.h>
 #include <linux/vfio.h>
 #include <linux/workqueue.h>
-#include <linux/mdev.h>
 #include <linux/notifier.h>
 #include <linux/dma-iommu.h>
 #include <linux/irqdomain.h>
@@ -1934,20 +1933,6 @@ static bool vfio_iommu_has_sw_msi(struct list_head *group_resv_regions,
 	return ret;
 }
 
-static bool vfio_bus_is_mdev(struct bus_type *bus)
-{
-	struct bus_type *mdev_bus;
-	bool ret = false;
-
-	mdev_bus = symbol_get(mdev_bus_type);
-	if (mdev_bus) {
-		ret = (bus == mdev_bus);
-		symbol_put(mdev_bus_type);
-	}
-
-	return ret;
-}
-
 /*
  * This is a helper function to insert an address range to iova list.
  * The list is initially created with a single entry corresponding to
@@ -2172,7 +2157,7 @@ static void vfio_iommu_iova_insert_copy(struct vfio_iommu *iommu,
 }
 
 static int vfio_iommu_type1_attach_group(void *iommu_data,
-					 struct iommu_group *iommu_group)
+		struct iommu_group *iommu_group, enum vfio_group_type type)
 {
 	struct vfio_iommu *iommu = iommu_data;
 	struct vfio_iommu_group *group;
@@ -2207,7 +2192,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
 	if (ret)
 		goto out_free;
 
-	if (vfio_bus_is_mdev(bus)) {
+	if (type == VFIO_EMULATED_IOMMU) {
 		if (!iommu->external_domain) {
 			INIT_LIST_HEAD(&domain->group_list);
 			iommu->external_domain = domain;