On 2022/4/12 15:39, Tian, Kevin wrote:
From: Lu Baolu <baolu...@linux.intel.com> Sent: Sunday, April 10, 2022 6:25 PM @@ -898,6 +941,20 @@ int iommu_group_add_device(struct iommu_group *group, struct device *dev) list_add_tail(&device->list, &group->devices); if (group->domain && !iommu_is_attach_deferred(dev)) ret = __iommu_attach_device(group->domain, dev); + + /* + * Use standard PCI bus topology, isolation features, and DMA + * alias quirks to set the immutable singleton attribute. If + * the device came from DT, assume it is static and then + * singleton can know from the device count in the group. + */ + if (dev_is_pci(dev)) + group->immutable_singleton = + pci_immutably_isolated(to_pci_dev(dev)); + else if (is_of_node(dev_fwnode(dev))) + group->immutable_singleton = + (iommu_group_device_count(group) == 1); +btw probably we also want to check when a 2nd device is added to a group marked as singleton, just in case some weird thing happens?
It depends on how we judge whether the group to which a DT device belongs is a singleton. As I explained in another thread, current trick doesn't support doing this. Best regards, baolu _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
