vfio-iommufd: Move noiommu compat validation out of vfio_iommufd_bind()

This moves the noiommu compat validation logic into vfio_df_group_open().
This is more consistent with what will be done in vfio device cdev path.

Reviewed-by: Kevin Tian <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Tested-by: Terrence Xu <[email protected]>
Tested-by: Nicolin Chen <[email protected]>
Tested-by: Matthew Rosato <[email protected]>
Tested-by: Yanting Jiang <[email protected]>
Tested-by: Shameer Kolothum <[email protected]>
Tested-by: Zhenzhong Duan <[email protected]>
Signed-off-by: Yi Liu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alex Williamson <[email protected]>

Author: yiliu1765

drivers/vfio/group.c

@@ -192,6 +192,19 @@ static int vfio_df_group_open(struct vfio_device_file *df)
 		vfio_device_group_get_kvm_safe(device);
 
 	df->iommufd = device->group->iommufd;
+	if (df->iommufd && vfio_device_is_noiommu(device) && device->open_count == 0) {
+		/*
+		 * Require no compat ioas to be assigned to proceed.  The basic
+		 * statement is that the user cannot have done something that
+		 * implies they expected translation to exist
+		 */
+		if (!capable(CAP_SYS_RAWIO) ||
+		    vfio_iommufd_device_has_compat_ioas(device, df->iommufd))
+			ret = -EPERM;
+		else
+			ret = 0;
+		goto out_put_kvm;
+	}
 
 	ret = vfio_df_open(df);
 	if (ret) {

drivers/vfio/iommufd.c

@@ -10,6 +10,14 @@
 MODULE_IMPORT_NS(IOMMUFD);
 MODULE_IMPORT_NS(IOMMUFD_VFIO);
 
+bool vfio_iommufd_device_has_compat_ioas(struct vfio_device *vdev,
+					 struct iommufd_ctx *ictx)
+{
+	u32 ioas_id;
+
+	return !iommufd_vfio_compat_ioas_get_id(ictx, &ioas_id);
+}
+
 int vfio_iommufd_bind(struct vfio_device *vdev, struct iommufd_ctx *ictx)
 {
 	u32 ioas_id;
@@ -18,20 +26,6 @@ int vfio_iommufd_bind(struct vfio_device *vdev, struct iommufd_ctx *ictx)
 
 	lockdep_assert_held(&vdev->dev_set->lock);
 
-	if (vfio_device_is_noiommu(vdev)) {
-		if (!capable(CAP_SYS_RAWIO))
-			return -EPERM;
-
-		/*
-		 * Require no compat ioas to be assigned to proceed. The basic
-		 * statement is that the user cannot have done something that
-		 * implies they expected translation to exist
-		 */
-		if (!iommufd_vfio_compat_ioas_get_id(ictx, &ioas_id))
-			return -EPERM;
-		return 0;
-	}
-
 	ret = vdev->ops->bind_iommufd(vdev, ictx, &device_id);
 	if (ret)
 		return ret;

drivers/vfio/vfio.h

@@ -234,9 +234,18 @@ static inline void vfio_container_cleanup(void)
 #endif
 
 #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);
 #else
+static inline bool
+vfio_iommufd_device_has_compat_ioas(struct vfio_device *vdev,
+				    struct iommufd_ctx *ictx)
+{
+	return false;
+}
+
 static inline int vfio_iommufd_bind(struct vfio_device *device,
 				    struct iommufd_ctx *ictx)
 {