[CHERRY-PICK] MdeModulePkg: Don't Allow Guard Pages to Cross Bin Boundaries#1774
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os-d merged 1 commit intomicrosoft:release/202511from Apr 23, 2026
Merged
[CHERRY-PICK] MdeModulePkg: Don't Allow Guard Pages to Cross Bin Boundaries#1774os-d merged 1 commit intomicrosoft:release/202511from
os-d merged 1 commit intomicrosoft:release/202511from
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…daries Currently, the DXE page allocator does not ensure that guard page allocations stay within the bin that it is attempting to allocate within. As a result, S4 resume is jeopardized by bins expanding due to guard pages, either into other bins or out of bins. This is caught by a new assert in CoreGetMemoryMap() to ensure the bins are correct. This fixes this by changing the internal heap guard API to return the adjusted size and start address of a proposed allocation. The page allocator then can ensure that the adjusted allocation still fits within the bin it is attempting to allocate within; if not, it will search for another descriptor. Signed-off-by: Oliver Smith-Denny <osde@microsoft.com> (cherry picked from commit 0f2dc7558713f1774bb7317e9fdcd371fcbb10cc)
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Workflow run: https://github.com/microsoft/mu_basecore/actions/runs/24849449116 This comment was automatically generated by the Mu QEMU PR Validation workflow. |
apop5
approved these changes
Apr 23, 2026
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## release/202511 #1774 +/- ##
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Coverage ? 1.84%
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Files ? 1151
Lines ? 376642
Branches ? 3196
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Hits ? 6936
Misses ? 369650
Partials ? 56
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cfernald
approved these changes
Apr 23, 2026
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Description
Currently, the DXE page allocator does not ensure that guard page allocations stay within the bin that it is attempting to allocate within. As a result, S4 resume is jeopardized by bins expanding due to guard pages, either into other bins or out of bins. This is caught by a new assert in CoreGetMemoryMap() to ensure the bins are correct.
This fixes this by changing the internal heap guard API to return the adjusted size and start address of a proposed allocation. The page allocator then can ensure that the adjusted allocation still fits within the bin it is attempting to allocate within; if not, it will search for another descriptor.
(cherry picked from edk2 commit 0f2dc7558713f1774bb7317e9fdcd371fcbb10cc)
How This Was Tested
On OvmfPkg and a physical Intel system.
Integration Instructions
N/A.