sriov vf get iommu group kernel code trace

VF device driver call:

pci_enable_sriov -> sriov_enable -> pci_iov_add_virtfn -> pci_device_add -> device_add ->

    blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
                                             BUS_NOTIFY_ADD_DEVICE, dev);

pci bus register a iommu notifier will be called when device_add start to notify:

static int __init pci_iommu_init(void)
{
        if (iommu_detected)
                intel_iommu_init();

        return 0;
}

/* Must execute after PCI subsystem */
fs_initcall(pci_iommu_init);

intel_iommu_init -> iommu_bus_init -> “nb->notifier_call = iommu_bus_notifier;”

        if (action == BUS_NOTIFY_ADD_DEVICE) {
                if (ops->add_device)
                        return ops->add_device(dev);

ops->add_device:

static struct iommu_ops intel_iommu_ops = {
        .capable        = intel_iommu_capable,
        .domain_alloc   = intel_iommu_domain_alloc,
        .domain_free    = intel_iommu_domain_free,
        .attach_dev     = intel_iommu_attach_device,
        .detach_dev     = intel_iommu_detach_device,
        .map            = intel_iommu_map,
        .unmap          = intel_iommu_unmap,
        .map_sg         = default_iommu_map_sg,
        .iova_to_phys   = intel_iommu_iova_to_phys,
        .add_device     =intel_iommu_add_device,
        .remove_device  = intel_iommu_remove_device,
        .pgsize_bitmap  = INTEL_IOMMU_PGSIZES,
};

intel_iommu_add_device:

static int intel_iommu_add_device(struct device *dev)
{
        struct intel_iommu *iommu;
        struct iommu_group *group;
        u8 bus, devfn;

        iommu = device_to_iommu(dev, &bus, &devfn);
        if (!iommu)
                return -ENODEV;

        iommu_device_link(iommu->iommu_dev, dev);

        group = iommu_group_get_for_dev(dev);

        if (IS_ERR(group))
                return PTR_ERR(group);

        iommu_group_put(group);
        return 0;
}

iommu_group_get_for_dev: