intel-iommu: Support IOMMU groups

Add IOMMU group support to Intel VT-d code. This driver sets up
devices ondemand, so make use of the add_device/remove_device
callbacks in IOMMU API to manage setting up the groups.

Signed-off-by: Alex Williamson <[e-mail]>
Signed-off-by: Joerg Roedel <[e-mail]>

drivers/iommu/intel-iommu.c

···
 	return 0;
 }
 
+static int intel_iommu_add_device(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct pci_dev *bridge, *dma_pdev;
+	struct iommu_group *group;
+	int ret;
+
+	if (!device_to_iommu(pci_domain_nr(pdev->bus),
+			     pdev->bus->number, pdev->devfn))
+		return -ENODEV;
+
+	bridge = pci_find_upstream_pcie_bridge(pdev);
+	if (bridge) {
+		if (pci_is_pcie(bridge))
+			dma_pdev = pci_get_domain_bus_and_slot(
+						pci_domain_nr(pdev->bus),
+						bridge->subordinate->number, 0);
+		else
+			dma_pdev = pci_dev_get(bridge);
+	} else
+		dma_pdev = pci_dev_get(pdev);
+
+	group = iommu_group_get(&dma_pdev->dev);
+	pci_dev_put(dma_pdev);
+	if (!group) {
+		group = iommu_group_alloc();
+		if (IS_ERR(group))
+			return PTR_ERR(group);
+	}
+
+	ret = iommu_group_add_device(group, dev);
+
+	iommu_group_put(group);
+	return ret;
+}
+
+static void intel_iommu_remove_device(struct device *dev)
+{
+	iommu_group_remove_device(dev);
+}
+
 static struct iommu_ops intel_iommu_ops = {
 	.domain_init	= intel_iommu_domain_init,
 	.domain_destroy = intel_iommu_domain_destroy,
···
 	.unmap		= intel_iommu_unmap,
 	.iova_to_phys	= intel_iommu_iova_to_phys,
 	.domain_has_cap = intel_iommu_domain_has_cap,
+	.add_device	= intel_iommu_add_device,
+	.remove_device	= intel_iommu_remove_device,
 	.pgsize_bitmap	= INTEL_IOMMU_PGSIZES,
 };