[PATCH 4.18 48/53] iommu/amd: Return devid as alias for ACPI HID devices

[Greg Kroah-Hartman]

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Arindam Nath <arindam.nath@xxxxxxx>

[ Upstream commit 5ebb1bc2d63d90dd204169e21fd7a0b4bb8c776e ]

ACPI HID devices do not actually have an alias for
them in the IVRS. But dev_data->alias is still used
for indexing into the IOMMU device table for devices
being handled by the IOMMU. So for ACPI HID devices,
we simply return the corresponding devid as an alias,
as parsed from IVRS table.

Signed-off-by: Arindam Nath <arindam.nath@xxxxxxx>
Fixes: 2bf9a0a12749 ('iommu/amd: Add iommu support for ACPI HID devices')
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/iommu/amd_iommu.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -246,7 +246,13 @@ static u16 get_alias(struct device *dev)
 
 	/* The callers make sure that get_device_id() does not fail here */
 	devid = get_device_id(dev);
+
+	/* For ACPI HID devices, we simply return the devid as such */
+	if (!dev_is_pci(dev))
+		return devid;
+
 	ivrs_alias = amd_iommu_alias_table[devid];
+
 	pci_for_each_dma_alias(pdev, __last_alias, &pci_alias);
 
 	if (ivrs_alias == pci_alias)