On Thu, Apr 14, 2022 at 03:46:04PM -0300, Jason Gunthorpe wrote: > The only user wants to get a pointer to the struct iommu_group associated > with the VFIO file being used. Instead of returning the group ID then > searching sysfs for that string just directly return the iommu_group > pointer already held by the vfio_group struct. > > It already has a safe lifetime due to the struct file kref. Except for the strange function pointer indirection this does looks sensible to me, but I wonder if we want to do this change even more high level: The only thing that needs the IOMMU group is the PPC kvm_spapr_tce_attach_iommu_group / kvm_spapr_tce_release_vfio_group helpers. And these use it only to find the iommu_table_group structure. Why can't we just have the vfio_group point to that table group diretly in vfio or the vfio SPAPR backend and remove all the convoluted lookups?
