microsoft/mu_basecore v2025110002.0.0

v2025110002.0.0

Repository: microsoft/mu_basecore

Tag: v2025110002.0.0

Published: 2026-06-02T21:56:24Z

Prerelease: no

Release notes:

What's Changed

⚠️ Breaking Changes

[2511] MdeModulePkg/Variable: Remove Mu RT cache buffer allocation changes [Rebase \& FF] @makubacki (#1781)

Change Details

Description

Project Mu had changes to move UEFI variable runtime cache allocation to DXE instead of PEI. The Project Mu MM model allows the runtime buffer allocations to be unblocked for MM access in DXE and allocating in DXE did not cause RT buffer fragmentation in the memory map to better accommodate hibernate resume.

With PEI memory buckets being added in https://github.com/microsoft/mu_basecore/pull/1759 to Project Mu beginning with the 2511 branch, the upstream flow to allocate the RT cache buffer in PEI can be restored

This PR reverts commits that added DXE runtime cache buffer allocation support individually, so it is clear exactly what is reverted and these changes can be skipped on future Mu release branches.

---

1. Revert "[CHERRY-PICK] MdeModulePkg/VariableSmmRuntimeDxe: Fix EFI_UNSUPPORTED leak (#1668)" 2. Revert "MdeModulePkg/Variable: Add PCD to control RT cache allocation (#1588)" 3. Revert "MdeModulePkg/VariableSmmRuntimeDxe: Disable var RT cache on alloc failure" 4. Revert "MdeModulePkg/Variable: Move RT cache buffer allocation to DXE"

• [x] Impacts functionality?
• [ ] Impacts security?
• [x] Breaking change?
• [ ] Includes tests?
• [ ] Includes documentation?

How This Was Tested

• Boot on QEMU Q35 and a physical Intel platform with the change (and PEI memory buckets present)
• Compared resulting files with edk2 variable code taking into account other unrelated Mu changes

Integration Instructions

• gEfiMdeModulePkgTokenSpaceGuid.PcdMigrateVariableRuntimeCacheBufferAllocation is removed from MdeModulePkg.dec so delete any references in that in platform code.
• It is recommended to ensure the PEI memory buckets PR referenced in this PR's description is included in the Mu Basecore code used by the platform so PEI memory buckets can be used to reduce runtime memory fragmentation.

Full Changelog: https://github.com/microsoft/mu_basecore/compare/v2025110001.0.12...v2025110002.0.0