On Wed, Jun 16, 2021 at 10:38:02PM +0800, Zhangfei Gao wrote: > +++ b/include/linux/iommu.h > @@ -87,6 +87,7 @@ struct iommu_domain { > void *handler_token; > struct iommu_domain_geometry geometry; > void *iova_cookie; > + int nested; This should probably be a bool : 1; Also this needs a user, so please just queue up a variant of this for the code that eventually relies on this information.