diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 374c129..5efadad 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -92,6 +92,7 @@
 	struct list_head dev_data_list;	  /* For global dev_data_list */
 	struct protection_domain *domain; /* Domain the device is bound to */
 	u16 devid;			  /* PCI Device ID */
+	u16 alias;			  /* Alias Device ID */
 	bool iommu_v2;			  /* Device can make use of IOMMUv2 */
 	bool passthrough;		  /* Device is identity mapped */
 	struct {
@@ -166,6 +167,13 @@
 	return container_of(dom, struct protection_domain, domain);
 }
 
+static inline u16 get_device_id(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+
+	return PCI_DEVID(pdev->bus->number, pdev->devfn);
+}
+
 static struct iommu_dev_data *alloc_dev_data(u16 devid)
 {
 	struct iommu_dev_data *dev_data;
@@ -203,6 +211,68 @@
 	return dev_data;
 }
 
+static int __last_alias(struct pci_dev *pdev, u16 alias, void *data)
+{
+	*(u16 *)data = alias;
+	return 0;
+}
+
+static u16 get_alias(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	u16 devid, ivrs_alias, pci_alias;
+
+	devid = get_device_id(dev);
+	ivrs_alias = amd_iommu_alias_table[devid];
+	pci_for_each_dma_alias(pdev, __last_alias, &pci_alias);
+
+	if (ivrs_alias == pci_alias)
+		return ivrs_alias;
+
+	/*
+	 * DMA alias showdown
+	 *
+	 * The IVRS is fairly reliable in telling us about aliases, but it
+	 * can't know about every screwy device.  If we don't have an IVRS
+	 * reported alias, use the PCI reported alias.  In that case we may
+	 * still need to initialize the rlookup and dev_table entries if the
+	 * alias is to a non-existent device.
+	 */
+	if (ivrs_alias == devid) {
+		if (!amd_iommu_rlookup_table[pci_alias]) {
+			amd_iommu_rlookup_table[pci_alias] =
+				amd_iommu_rlookup_table[devid];
+			memcpy(amd_iommu_dev_table[pci_alias].data,
+			       amd_iommu_dev_table[devid].data,
+			       sizeof(amd_iommu_dev_table[pci_alias].data));
+		}
+
+		return pci_alias;
+	}
+
+	pr_info("AMD-Vi: Using IVRS reported alias %02x:%02x.%d "
+		"for device %s[%04x:%04x], kernel reported alias "
+		"%02x:%02x.%d\n", PCI_BUS_NUM(ivrs_alias), PCI_SLOT(ivrs_alias),
+		PCI_FUNC(ivrs_alias), dev_name(dev), pdev->vendor, pdev->device,
+		PCI_BUS_NUM(pci_alias), PCI_SLOT(pci_alias),
+		PCI_FUNC(pci_alias));
+
+	/*
+	 * If we don't have a PCI DMA alias and the IVRS alias is on the same
+	 * bus, then the IVRS table may know about a quirk that we don't.
+	 */
+	if (pci_alias == devid &&
+	    PCI_BUS_NUM(ivrs_alias) == pdev->bus->number) {
+		pdev->dev_flags |= PCI_DEV_FLAGS_DMA_ALIAS_DEVFN;
+		pdev->dma_alias_devfn = ivrs_alias & 0xff;
+		pr_info("AMD-Vi: Added PCI DMA alias %02x.%d for %s\n",
+			PCI_SLOT(ivrs_alias), PCI_FUNC(ivrs_alias),
+			dev_name(dev));
+	}
+
+	return ivrs_alias;
+}
+
 static struct iommu_dev_data *find_dev_data(u16 devid)
 {
 	struct iommu_dev_data *dev_data;
@@ -215,13 +285,6 @@
 	return dev_data;
 }
 
-static inline u16 get_device_id(struct device *dev)
-{
-	struct pci_dev *pdev = to_pci_dev(dev);
-
-	return PCI_DEVID(pdev->bus->number, pdev->devfn);
-}
-
 static struct iommu_dev_data *get_dev_data(struct device *dev)
 {
 	return dev->archdata.iommu;
@@ -349,6 +412,8 @@
 	if (!dev_data)
 		return -ENOMEM;
 
+	dev_data->alias = get_alias(dev);
+
 	if (pci_iommuv2_capable(pdev)) {
 		struct amd_iommu *iommu;
 
@@ -369,7 +434,7 @@
 	u16 devid, alias;
 
 	devid = get_device_id(dev);
-	alias = amd_iommu_alias_table[devid];
+	alias = get_alias(dev);
 
 	memset(&amd_iommu_dev_table[devid], 0, sizeof(struct dev_table_entry));
 	memset(&amd_iommu_dev_table[alias], 0, sizeof(struct dev_table_entry));
@@ -1061,7 +1126,7 @@
 	int ret;
 
 	iommu = amd_iommu_rlookup_table[dev_data->devid];
-	alias = amd_iommu_alias_table[dev_data->devid];
+	alias = dev_data->alias;
 
 	ret = iommu_flush_dte(iommu, dev_data->devid);
 	if (!ret && alias != dev_data->devid)
@@ -2039,7 +2104,7 @@
 	bool ats;
 
 	iommu = amd_iommu_rlookup_table[dev_data->devid];
-	alias = amd_iommu_alias_table[dev_data->devid];
+	alias = dev_data->alias;
 	ats   = dev_data->ats.enabled;
 
 	/* Update data structures */
@@ -2073,7 +2138,7 @@
 		return;
 
 	iommu = amd_iommu_rlookup_table[dev_data->devid];
-	alias = amd_iommu_alias_table[dev_data->devid];
+	alias = dev_data->alias;
 
 	/* decrease reference counters */
 	dev_data->domain->dev_iommu[iommu->index] -= 1;