[PATCH 0/1][SRU][Plucky/Oracular] Handle IOMMU IVRS entries with mismatched UID on AMD Strix or newer platforms

[You-Sheng Yang]

BugLink: https://bugs.launchpad.net/bugs/2115174

[ Impact ]

A BIOS upgrade has changed the IVRS DTE UID for a device that no longer
matches the UID in the SSDT and may potentially affect s0i3 on Linux
systems.

[ Test Plan ]

1. Dump IVRS table:
```
# install acpica-tools
$ sudo apt-get install --no-install-recommends --yes acpica-tools
$ sudo acpidump -o acpi.dump
$ acpixtract -a acpi.dump
$ iasl -d ivrs.dat

```

2. Search for subtable type F0 in decoded ivrs.dsl:
```
[176h 0374 001h]               Subtable Type : F0 [Device Entry: ACPI HID Named Device]
[177h 0375 002h]                   Device ID : 00A5
[179h 0377 001h] Data Setting (decoded below) : 40
                                    INITPass : 0
                                    EIntPass : 0
                                     NMIPass : 0
                                    Reserved : 0
                                 System MGMT : 0
                                  LINT0 Pass : 1
                                  LINT1 Pass : 0
[17Ah 0378 008h]                    ACPI HID : "AMDI0020"
[182h 0386 008h]                    ACPI CID : 0000000000000000
[18Ah 0394 001h]                  UID Format : 02
[18Bh 0395 001h]                  UID Length : 04
[18Ch 0396 004h]                         UID : "ID01"
```

3. Locate the MHSP device from SSDT tables:
```
 grep -n 'Device (MHSP)' -A4 ssdt*.dsl
ssdt34.dsl:25:        Device (MHSP)
ssdt34.dsl-26-        {
ssdt34.dsl-27-            Name (_ADR, Zero)  // _ADR: Address
ssdt34.dsl-28-            Name (_HID, "MSFT0201")  // _HID: Hardware ID
ssdt34.dsl-29-            Name (_UID, One)  // _UID: Unique ID
```

4. From IVRS the UID is "ID01" yet it's numeric 1 from SSDT, so this system
   is affected.

[ Where problems could occur ]

This restore the ability to match UID correctly as before. No side effect.

[ Other Info ]

Such BIOS upgrade may occur for Strix, Krackan, Strix Halo, and Gorgon
Point systems. Nominate for series with kernels >= v6.11 and < v6.16-rc1.

Mario Limonciello (1):
  iommu/amd: Allow matching ACPI HID devices without matching UIDs

 drivers/iommu/amd/iommu.c | 33 ++++++++++++++++++++++++++++-----
 1 file changed, 28 insertions(+), 5 deletions(-)

-- 
2.48.1