> From: Eric Auger <eric.auger@xxxxxxxxxx> > Sent: Monday, November 28, 2022 1:49 AM > > +struct iommu_ioas_copy { > > + __u32 size; > > + __u32 flags; > > + __u32 dst_ioas_id; > > + __u32 src_ioas_id; > is src_ioas_id == dst_ioas_id allowed? I suppose so. iommufd_ioas_copy() simply gets a reference to underlying iopt_pages according to [src_ioas_id, src_iova] and then map it into [dst_ioas_id, dst_iova]. It doesn’t matter whether iopt_pages comes from a same or different ioas. The only restriction is that the src/dst ranges don't overlap.