vfio: Add external user check extension interface

This lets us check extensions, particularly VFIO_DMA_CC_IOMMU using
the external user interface, allowing KVM to probe IOMMU coherency.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 24579a0312a0..81022a52bc34 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -96,5 +96,7 @@ extern void vfio_unregister_iommu_driver(
 extern struct vfio_group *vfio_group_get_external_user(struct file *filep);
 extern void vfio_group_put_external_user(struct vfio_group *group);
 extern int vfio_external_user_iommu_id(struct vfio_group *group);
+extern long vfio_external_check_extension(struct vfio_group *group,
+                                          unsigned long arg);
 
 #endif /* VFIO_H */