vfio: Record devid in vfio_device_file

.bind_iommufd() will generate an ID to represent this bond, which is
needed by userspace for further usage. Store devid in vfio_device_file
to avoid passing the pointer in multiple places.
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Terrence Xu <terrence.xu@intel.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Matthew Rosato <mjrosato@linux.ibm.com>
Tested-by: Yanting Jiang <yanting.jiang@intel.com>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Tested-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20230718135551.6592-13-yi.l.liu@intel.comSigned-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/iommufd.c

@@ -18,14 +18,14 @@ bool vfio_iommufd_device_has_compat_ioas(struct vfio_device *vdev,
 	return !iommufd_vfio_compat_ioas_get_id(ictx, &ioas_id);
 }
 
-int vfio_iommufd_bind(struct vfio_device *vdev, struct iommufd_ctx *ictx)
+int vfio_df_iommufd_bind(struct vfio_device_file *df)
 {
-	u32 device_id;
+	struct vfio_device *vdev = df->device;
+	struct iommufd_ctx *ictx = df->iommufd;
 
 	lockdep_assert_held(&vdev->dev_set->lock);
 
-	/* The legacy path has no way to return the device id */
-	return vdev->ops->bind_iommufd(vdev, ictx, &device_id);
+	return vdev->ops->bind_iommufd(vdev, ictx, &df->devid);
 }
 
 int vfio_iommufd_compat_attach_ioas(struct vfio_device *vdev,
@@ -48,8 +48,10 @@ int vfio_iommufd_compat_attach_ioas(struct vfio_device *vdev,
 	return vdev->ops->attach_ioas(vdev, &ioas_id);
 }
 
-void vfio_iommufd_unbind(struct vfio_device *vdev)
+void vfio_df_iommufd_unbind(struct vfio_device_file *df)
 {
+	struct vfio_device *vdev = df->device;
+
 	lockdep_assert_held(&vdev->dev_set->lock);
 
 	if (vfio_device_is_noiommu(vdev))

drivers/vfio/vfio.h

@@ -21,6 +21,7 @@ struct vfio_device_file {
 	struct vfio_group *group;
 
 	u8 access_granted;
+	u32 devid; /* only valid when iommufd is valid */
 	spinlock_t kvm_ref_lock; /* protect kvm field */
 	struct kvm *kvm;
 	struct iommufd_ctx *iommufd; /* protected by struct vfio_device_set::lock */
@@ -236,8 +237,8 @@ static inline void vfio_container_cleanup(void)
 #if IS_ENABLED(CONFIG_IOMMUFD)
 bool vfio_iommufd_device_has_compat_ioas(struct vfio_device *vdev,
 					 struct iommufd_ctx *ictx);
-int vfio_iommufd_bind(struct vfio_device *device, struct iommufd_ctx *ictx);
-void vfio_iommufd_unbind(struct vfio_device *device);
+int vfio_df_iommufd_bind(struct vfio_device_file *df);
+void vfio_df_iommufd_unbind(struct vfio_device_file *df);
 int vfio_iommufd_compat_attach_ioas(struct vfio_device *device,
 				    struct iommufd_ctx *ictx);
 #else
@@ -248,13 +249,12 @@ vfio_iommufd_device_has_compat_ioas(struct vfio_device *vdev,
 	return false;
 }
 
-static inline int vfio_iommufd_bind(struct vfio_device *device,
-				    struct iommufd_ctx *ictx)
+static inline int vfio_df_iommufd_bind(struct vfio_device_file *fd)
 {
 	return -EOPNOTSUPP;
 }
 
-static inline void vfio_iommufd_unbind(struct vfio_device *device)
+static inline void vfio_df_iommufd_unbind(struct vfio_device_file *df)
 {
 }
 

drivers/vfio/vfio_main.c

@@ -446,7 +446,7 @@ static int vfio_df_device_first_open(struct vfio_device_file *df)
 		return -ENODEV;
 
 	if (iommufd)
-		ret = vfio_iommufd_bind(device, iommufd);
+		ret = vfio_df_iommufd_bind(df);
 	else
 		ret = vfio_device_group_use_iommu(device);
 	if (ret)
@@ -461,7 +461,7 @@ static int vfio_df_device_first_open(struct vfio_device_file *df)
 
 err_unuse_iommu:
 	if (iommufd)
-		vfio_iommufd_unbind(device);
+		vfio_df_iommufd_unbind(df);
 	else
 		vfio_device_group_unuse_iommu(device);
 err_module_put:
@@ -479,7 +479,7 @@ static void vfio_df_device_last_close(struct vfio_device_file *df)
 	if (device->ops->close_device)
 		device->ops->close_device(device);
 	if (iommufd)
-		vfio_iommufd_unbind(device);
+		vfio_df_iommufd_unbind(df);
 	else
 		vfio_device_group_unuse_iommu(device);
 	module_put(device->dev->driver->owner);