MtrrLibSetBelow1MBMemoryAttribute() may be called multiple times. It's possible that in a 2nd call, Modified[0] is set to TRUE in 1st call but ClearMasks[0] and OrMasks[0] is uninitialized in 2nd call. It causes FixedSettings->Mtrr[0] be set to random data.
The patch fixes this issue by introducing a local Modified[] array and only updates FixedSettings->Mtrr[] when LocalModified[i] is TRUE. Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Ruiyu Ni <[email protected]> Cc: Hao A Wu <[email protected]> --- UefiCpuPkg/Library/MtrrLib/MtrrLib.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) diff --git a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c index cb22558103..200becdd4a 100644 --- a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c +++ b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c @@ -2114,22 +2114,32 @@ MtrrLibSetBelow1MBMemoryAttribute ( UINT64 OrMask; UINT64 ClearMasks[ARRAY_SIZE (mMtrrLibFixedMtrrTable)]; UINT64 OrMasks[ARRAY_SIZE (mMtrrLibFixedMtrrTable)]; + BOOLEAN LocalModified[ARRAY_SIZE (mMtrrLibFixedMtrrTable)]; ASSERT (BaseAddress < BASE_1MB); + SetMem (LocalModified, sizeof (LocalModified), FALSE); + + // + // (Value & ~0 | 0) still equals to (Value) + // + SetMem64 (ClearMasks, sizeof (ClearMasks), 0); + SetMem64 (OrMasks, sizeof (OrMasks), 0); + MsrIndex = (UINT32)-1; while ((BaseAddress < BASE_1MB) && (Length != 0)) { Status = MtrrLibProgramFixedMtrr (Type, &BaseAddress, &Length, &MsrIndex, &ClearMask, &OrMask); if (RETURN_ERROR (Status)) { return Status; } - ClearMasks[MsrIndex] = ClearMask; - OrMasks[MsrIndex] = OrMask; - Modified[MsrIndex] = TRUE; + ClearMasks[MsrIndex] = ClearMask; + OrMasks[MsrIndex] = OrMask; + Modified[MsrIndex] = TRUE; + LocalModified[MsrIndex] = TRUE; } for (MsrIndex = 0; MsrIndex < ARRAY_SIZE (mMtrrLibFixedMtrrTable); MsrIndex++) { - if (Modified[MsrIndex]) { + if (LocalModified[MsrIndex]) { FixedSettings->Mtrr[MsrIndex] = (FixedSettings->Mtrr[MsrIndex] & ~ClearMasks[MsrIndex]) | OrMasks[MsrIndex]; } } @@ -2354,6 +2364,7 @@ MtrrSetMemoryAttributesInMtrrSettings ( // // 3. Apply the below-1MB memory attribute settings. // + ZeroMem (WorkingFixedSettings.Mtrr, sizeof (WorkingFixedSettings.Mtrr)); for (Index = 0; Index < RangeCount; Index++) { if (Ranges[Index].BaseAddress >= BASE_1MB) { continue; -- 2.12.2.windows.2 _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
