2 files changed, 57 insertions, 5 deletions

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 7fa97a5e3ea..cb63cc5d94d 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -140,6 +140,9 @@ static void free_dev_data(struct iommu_dev_data *dev_data)
         list_del(&dev_data->dev_data_list);
         spin_unlock_irqrestore(&dev_data_list_lock, flags);
 
+        if (dev_data->group)
+                iommu_group_put(dev_data->group);
+
         kfree(dev_data);
 }
 
@@ -343,11 +346,25 @@ static int use_pdev_iommu_group(struct pci_dev *pdev, struct device *dev)
         return ret;
 }
 
+static int use_dev_data_iommu_group(struct iommu_dev_data *dev_data,
+                                    struct device *dev)
+{
+        if (!dev_data->group) {
+                struct iommu_group *group = iommu_group_alloc();
+                if (IS_ERR(group))
+                        return PTR_ERR(group);
+
+                dev_data->group = group;
+        }
+
+        return iommu_group_add_device(dev_data->group, dev);
+}
+
 static int init_iommu_group(struct device *dev)
 {
         struct iommu_dev_data *dev_data;
         struct iommu_group *group;
-        struct pci_dev *dma_pdev = NULL;
+        struct pci_dev *dma_pdev;
         int ret;
 
         group = iommu_group_get(dev);
@@ -362,18 +379,52 @@ static int init_iommu_group(struct device *dev)
 
         if (dev_data->alias_data) {
                 u16 alias;
+                struct pci_bus *bus;
+
+                if (dev_data->alias_data->group)
+                        goto use_group;
 
+                /*
+                 * If the alias device exists, it's effectively just a first
+                 * level quirk for finding the DMA source.
+                 */
                 alias = amd_iommu_alias_table[dev_data->devid];
                 dma_pdev = pci_get_bus_and_slot(alias >> 8, alias & 0xff);
-        }
+                if (dma_pdev) {
+                        dma_pdev = get_isolation_root(dma_pdev);
+                        goto use_pdev;
+                }
+
+                /*
+                 * If the alias is virtual, try to find a parent device
+                 * and test whether the IOMMU group is actualy rooted above
+                 * the alias.  Be careful to also test the parent device if
+                 * we think the alias is the root of the group.
+                 */
+                bus = pci_find_bus(0, alias >> 8);
+                if (!bus)
+                        goto use_group;
+
+                bus = find_hosted_bus(bus);
+                if (IS_ERR(bus) || !bus->self)
+                        goto use_group;
 
-        if (!dma_pdev)
-                dma_pdev = pci_dev_get(to_pci_dev(dev));
+                dma_pdev = get_isolation_root(pci_dev_get(bus->self));
+                if (dma_pdev != bus->self || (dma_pdev->multifunction &&
+                    !pci_acs_enabled(dma_pdev, REQ_ACS_FLAGS)))
+                        goto use_pdev;
+
+                pci_dev_put(dma_pdev);
+                goto use_group;
+        }
 
-        dma_pdev = get_isolation_root(dma_pdev);
+        dma_pdev = get_isolation_root(pci_dev_get(to_pci_dev(dev)));
+use_pdev:
         ret = use_pdev_iommu_group(dma_pdev, dev);
         pci_dev_put(dma_pdev);
         return ret;
+use_group:
+        return use_dev_data_iommu_group(dev_data->alias_data, dev);
 }
 
 static int iommu_init_device(struct device *dev)
diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
index c9aa3d079ff..e38ab438bb3 100644
--- a/drivers/iommu/amd_iommu_types.h
+++ b/drivers/iommu/amd_iommu_types.h
@@ -426,6 +426,7 @@ struct iommu_dev_data {
         struct iommu_dev_data *alias_data;/* The alias dev_data */
         struct protection_domain *domain; /* Domain the device is bound to */
         atomic_t bind;                    /* Domain attach reference count */
+        struct iommu_group *group;        /* IOMMU group for virtual aliases */
         u16 devid;                        /* PCI Device ID */
         bool iommu_v2;                    /* Device can make use of IOMMUv2 */
         bool passthrough;                 /* Default for device is pt_domain */