[PATCH v13 11/22] vfio-iommufd: Split bind/attach into two steps

[Yi Liu <yi.l.liu@xxxxxxxxx>]

This aligns the bind/attach logic with the coming vfio device cdev support.

Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Tested-by: Terrence Xu <terrence.xu@xxxxxxxxx>
Tested-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
Tested-by: Matthew Rosato <mjrosato@xxxxxxxxxxxxx>
Tested-by: Yanting Jiang <yanting.jiang@xxxxxxxxx>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@xxxxxxxxxx>
Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
---
 drivers/vfio/group.c   | 17 +++++++++++++----
 drivers/vfio/iommufd.c | 35 +++++++++++++++++------------------
 drivers/vfio/vfio.h    |  9 +++++++++
 3 files changed, 39 insertions(+), 22 deletions(-)

diff --git a/drivers/vfio/group.c b/drivers/vfio/group.c
index b8b77daf7aa6..41a09a2df690 100644
--- a/drivers/vfio/group.c
+++ b/drivers/vfio/group.c
@@ -207,9 +207,13 @@ static int vfio_df_group_open(struct vfio_device_file *df)
 	}
 
 	ret = vfio_df_open(df);
-	if (ret) {
-		df->iommufd = NULL;
+	if (ret)
 		goto out_put_kvm;
+
+	if (df->iommufd && device->open_count == 1) {
+		ret = vfio_iommufd_compat_attach_ioas(device, df->iommufd);
+		if (ret)
+			goto out_close_device;
 	}
 
 	/*
@@ -218,12 +222,17 @@ static int vfio_df_group_open(struct vfio_device_file *df)
 	 */
 	smp_store_release(&df->access_granted, true);
 
+	mutex_unlock(&device->dev_set->lock);
+	mutex_unlock(&device->group->group_lock);
+	return 0;
+
+out_close_device:
+	vfio_df_close(df);
 out_put_kvm:
+	df->iommufd = NULL;
 	if (device->open_count == 0)
 		vfio_device_put_kvm(device);
-
 	mutex_unlock(&device->dev_set->lock);
-
 out_unlock:
 	mutex_unlock(&device->group->group_lock);
 	return ret;
diff --git a/drivers/vfio/iommufd.c b/drivers/vfio/iommufd.c
index 36f838dad084..91fdae69bb45 100644
--- a/drivers/vfio/iommufd.c
+++ b/drivers/vfio/iommufd.c
@@ -20,33 +20,32 @@ bool vfio_iommufd_device_has_compat_ioas(struct vfio_device *vdev,
 
 int vfio_iommufd_bind(struct vfio_device *vdev, struct iommufd_ctx *ictx)
 {
-	u32 ioas_id;
 	u32 device_id;
+
+	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);
+}
+
+int vfio_iommufd_compat_attach_ioas(struct vfio_device *vdev,
+				    struct iommufd_ctx *ictx)
+{
+	u32 ioas_id;
 	int ret;
 
 	lockdep_assert_held(&vdev->dev_set->lock);
 
-	ret = vdev->ops->bind_iommufd(vdev, ictx, &device_id);
-	if (ret)
-		return ret;
+	/* compat noiommu does not need to do ioas attach */
+	if (vfio_device_is_noiommu(vdev))
+		return 0;
 
 	ret = iommufd_vfio_compat_ioas_get_id(ictx, &ioas_id);
 	if (ret)
-		goto err_unbind;
-	ret = vdev->ops->attach_ioas(vdev, &ioas_id);
-	if (ret)
-		goto err_unbind;
-
-	/*
-	 * The legacy path has no way to return the device id or the selected
-	 * pt_id
-	 */
-	return 0;
+		return ret;
 
-err_unbind:
-	if (vdev->ops->unbind_iommufd)
-		vdev->ops->unbind_iommufd(vdev);
-	return ret;
+	/* The legacy path has no way to return the selected pt_id */
+	return vdev->ops->attach_ioas(vdev, &ioas_id);
 }
 
 void vfio_iommufd_unbind(struct vfio_device *vdev)
diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h
index 300cab04f4e1..04755379940c 100644
--- a/drivers/vfio/vfio.h
+++ b/drivers/vfio/vfio.h
@@ -238,6 +238,8 @@ 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_iommufd_compat_attach_ioas(struct vfio_device *device,
+				    struct iommufd_ctx *ictx);
 #else
 static inline bool
 vfio_iommufd_device_has_compat_ioas(struct vfio_device *vdev,
@@ -255,6 +257,13 @@ static inline int vfio_iommufd_bind(struct vfio_device *device,
 static inline void vfio_iommufd_unbind(struct vfio_device *device)
 {
 }
+
+static inline int
+vfio_iommufd_compat_attach_ioas(struct vfio_device *device,
+				struct iommufd_ctx *ictx)
+{
+	return -EOPNOTSUPP;
+}
 #endif
 
 #if IS_ENABLED(CONFIG_VFIO_VIRQFD)
-- 
2.34.1