diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index 5a55bef8e379a31eea469947c50e0f973f9171b0..2d74641b7f7bc5aa51a524e9a018e84cdb8fac9a 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -368,6 +368,8 @@ static int set_hpet_sid(struct irte *irte, u8 id)
 struct set_msi_sid_data {
 	struct pci_dev *pdev;
 	u16 alias;
+	int count;
+	int busmatch_count;
 };
 
 static int set_msi_sid_cb(struct pci_dev *pdev, u16 alias, void *opaque)
@@ -376,6 +378,10 @@ static int set_msi_sid_cb(struct pci_dev *pdev, u16 alias, void *opaque)
 
 	data->pdev = pdev;
 	data->alias = alias;
+	data->count++;
+
+	if (PCI_BUS_NUM(alias) == pdev->bus->number)
+		data->busmatch_count++;
 
 	return 0;
 }
@@ -387,6 +393,8 @@ static int set_msi_sid(struct irte *irte, struct pci_dev *dev)
 	if (!irte || !dev)
 		return -1;
 
+	data.count = 0;
+	data.busmatch_count = 0;
 	pci_for_each_dma_alias(dev, set_msi_sid_cb, &data);
 
 	/*
@@ -395,6 +403,11 @@ static int set_msi_sid(struct irte *irte, struct pci_dev *dev)
 	 * device is the case of a PCIe-to-PCI bridge, where the alias is for
 	 * the subordinate bus.  In this case we can only verify the bus.
 	 *
+	 * If there are multiple aliases, all with the same bus number,
+	 * then all we can do is verify the bus. This is typical in NTB
+	 * hardware which use proxy IDs where the device will generate traffic
+	 * from multiple devfn numbers on the same bus.
+	 *
 	 * If the alias device is on a different bus than our source device
 	 * then we have a topology based alias, use it.
 	 *
@@ -405,6 +418,8 @@ static int set_msi_sid(struct irte *irte, struct pci_dev *dev)
 	if (PCI_BUS_NUM(data.alias) != data.pdev->bus->number)
 		set_irte_verify_bus(irte, PCI_BUS_NUM(data.alias),
 				    dev->bus->number);
+	else if (data.count >= 2 && data.busmatch_count == data.count)
+		set_irte_verify_bus(irte, dev->bus->number, dev->bus->number);
 	else if (data.pdev->bus->number != dev->bus->number)
 		set_irte_sid(irte, SVT_VERIFY_SID_SQ, SQ_ALL_16, data.alias);
 	else