The PCI PASID enabling interface guarantees that the address space used by each PASID is unique. This is achieved by checking that the PCI ACS path is enabled for the device. If the path is not enabled, then the PASID feature cannot be used. if (!pci_acs_path_enabled(pdev, NULL, PCI_ACS_RR | PCI_ACS_UF)) return -EINVAL; The PASID array is not an attribute of the IOMMU group. It is more natural to store the PASID array in the per-device IOMMU data. This makes the code clearer and easier to understand. No functional changes are intended. Please help review and suggest. Lu Baolu (2): iommu: Consolidate pasid dma ownership check iommu: Move pasid array from group to device include/linux/iommu.h | 2 + drivers/iommu/iommu.c | 105 +++++++++++++++++------------------------- 2 files changed, 43 insertions(+), 64 deletions(-) -- 2.34.1