> From: Jason Gunthorpe <jgg@xxxxxxxxxx> > Sent: Tuesday, August 27, 2024 11:52 PM > > For SMMUv3 the parent must be a S2 domain, which can be composed > into a IOMMU_DOMAIN_NESTED. > > In future the S2 parent will also need a VMID linked to the VIOMMU and > even to KVM. > > Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx> Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>, with a nit: > @@ -3103,7 +3103,8 @@ arm_smmu_domain_alloc_user(struct device *dev, > u32 flags, > const struct iommu_user_data *user_data) > { > struct arm_smmu_master *master = dev_iommu_priv_get(dev); > - const u32 PAGING_FLAGS = IOMMU_HWPT_ALLOC_DIRTY_TRACKING; > + const u32 PAGING_FLAGS = IOMMU_HWPT_ALLOC_DIRTY_TRACKING | > + IOMMU_HWPT_ALLOC_NEST_PARENT; lowercase for variable name.