Reviewed-by: Hao Wu <[email protected]>
Best Regards, Hao Wu > -----Original Message----- > From: Ni, Ruiyu > Sent: Thursday, October 19, 2017 10:49 AM > To: [email protected] > Cc: Wu, Hao A > Subject: [PATCH] UefiCpuPkg/MtrrLib: Fix bug that may incorrectly set <1MB > attribute > > 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
