6.15-stable review patch. If anyone has any objections, please let me know.
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From: Mario Limonciello mario.limonciello@amd.com
[ Upstream commit 51c33f333bbf7bdb6aa2a327e3a3e4bbb2591511 ]
A BIOS upgrade has changed the IVRS DTE UID for a device that no longer matches the UID in the SSDT. In this case there is only one ACPI device on the system with that _HID but the _UID mismatch.
IVRS: ``` Subtable Type : F0 [Device Entry: ACPI HID Named Device] Device ID : 0060 Data Setting (decoded below) : 40 INITPass : 0 EIntPass : 0 NMIPass : 0 Reserved : 0 System MGMT : 0 LINT0 Pass : 1 LINT1 Pass : 0 ACPI HID : "MSFT0201" ACPI CID : 0000000000000000 UID Format : 02 UID Length : 09 UID : "_SB.MHSP" ```
SSDT: ``` Device (MHSP) { Name (_ADR, Zero) // _ADR: Address Name (_HID, "MSFT0201") // _HID: Hardware ID Name (_UID, One) // _UID: Unique ID ```
To handle this case; while enumerating ACPI devices in get_acpihid_device_id() count the number of matching ACPI devices with a matching _HID. If there is exactly one _HID match then accept it even if the UID doesn't match. Other operating systems allow this, but the current IVRS spec leaves some ambiguity whether to allow or disallow it. This should be clarified in future revisions of the spec. Output 'Firmware Bug' for this case to encourage it to be solved in the BIOS.
Signed-off-by: Mario Limonciello mario.limonciello@amd.com Reviewed-by: Vasant Hegde vasant.hegde@amd.com Link: https://lore.kernel.org/r/20250512173129.1274275-1-superm1@kernel.org Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iommu/amd/iommu.c | 33 ++++++++++++++++++++++++++++----- 1 file changed, 28 insertions(+), 5 deletions(-)
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c index f34209b08b4c5..a05e0eb1729bf 100644 --- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -241,7 +241,9 @@ static inline int get_acpihid_device_id(struct device *dev, struct acpihid_map_entry **entry) { struct acpi_device *adev = ACPI_COMPANION(dev); - struct acpihid_map_entry *p; + struct acpihid_map_entry *p, *p1 = NULL; + int hid_count = 0; + bool fw_bug;
if (!adev) return -ENODEV; @@ -249,12 +251,33 @@ static inline int get_acpihid_device_id(struct device *dev, list_for_each_entry(p, &acpihid_map, list) { if (acpi_dev_hid_uid_match(adev, p->hid, p->uid[0] ? p->uid : NULL)) { - if (entry) - *entry = p; - return p->devid; + p1 = p; + fw_bug = false; + hid_count = 1; + break; + } + + /* + * Count HID matches w/o UID, raise FW_BUG but allow exactly one match + */ + if (acpi_dev_hid_match(adev, p->hid)) { + p1 = p; + hid_count++; + fw_bug = true; } } - return -EINVAL; + + if (!p1) + return -EINVAL; + if (fw_bug) + dev_err_once(dev, FW_BUG "No ACPI device matched UID, but %d device%s matched HID.\n", + hid_count, hid_count > 1 ? "s" : ""); + if (hid_count > 1) + return -EINVAL; + if (entry) + *entry = p1; + + return p1->devid; }
static inline int get_device_sbdf_id(struct device *dev)