ArmPkg: MmCommunicationDxe: Fix Comm Buffer Init#1803
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⏩ QEMU Validation SkippedThe PR was merged before validation completed. This comment was automatically generated by the Mu QEMU PR Validation workflow. |
makubacki
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May 20, 2026
makubacki
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May 20, 2026
Currently, MmCommunicationDxe expects the MM comm buffer to either be not added by the platform or added and allocated by the platform. However, not all platforms follow this pattern. This commit makes the handling more generic by checking to see if a GCD descriptor exists that covers this range. If it does, the capabilities are updated as needed. If only a partial desc exists for this range, the driver will fail as that is a platform misconfiguration. If the descriptor does not exist, the driver will add the buffer. Then, for all successful cases, the attributes are updated on the buffer to what the driver expects them to be. Signed-off-by: Oliver Smith-Denny <osde@microsoft.com>
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@makubacki I addressed the current feedback and re-tested, please re-review when you have a chance. |
kuqin12
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May 20, 2026
makubacki
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May 20, 2026
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Description
Currently, MmCommunicationDxe expects the MM comm buffer to either be not added by the platform or added and allocated by the platform. However, not all platforms follow this pattern.
This commit makes the handling more generic by checking to see if a GCD descriptor exists that covers this range. If it does, the capabilities are updated as needed. If only a partial desc exists for this range, the driver will fail as that is a platform misconfiguration.
If the descriptor does not exist, the driver will add the buffer.
Then, for all successful cases, the attributes are updated on the buffer to what the driver expects them to be.
This will be taken to edk2 in parallel.
How This Was Tested
Tested on an aarch64 platform that was producing the HOB but not having it allocated. This fixed it.
Integration Instructions
Platforms must either not produce a resource descriptor HOB for the MM Communicate Buffer or must produce a HOB fully covering the region.