From 1c29d03869355a5e9dfafb88332c139d8c5c2215 Mon Sep 17 00:00:00 2001 From: Ruiyu Ni Date: Tue, 17 Oct 2017 09:46:27 +0800 Subject: [PATCH] UefiCpuPkg/MtrrLib: Fix MtrrDebugPrintAllMtrrsWorker to avoid hang ARRAY_SIZE(Mtrrs->Variables.Mtrr) was used in MtrrDebugPrintAllMtrrsWorker() to parse the MTRR registers. Instead, the actual variable MTRR count should be used. Otherwise, the uninitialized random data in MtrrSetting may cause MtrrLibSetMemoryType() hang. Steven Shi found this bug in QEMU when using Q35 chip. Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Ruiyu Ni Reviewed-by: Steven Shi Cc: Laszlo Ersek --- UefiCpuPkg/Library/MtrrLib/MtrrLib.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c index 2fd1d0153e..cb22558103 100644 --- a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c +++ b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c @@ -2776,6 +2776,7 @@ MtrrDebugPrintAllMtrrsWorker ( UINTN RangeCount; UINT64 MtrrValidBitsMask; UINT64 MtrrValidAddressMask; + UINT32 VariableMtrrCount; MTRR_MEMORY_RANGE Ranges[ ARRAY_SIZE (mMtrrLibFixedMtrrTable) * sizeof (UINT64) + 2 * ARRAY_SIZE (Mtrrs->Variables.Mtrr) + 1 ]; @@ -2785,6 +2786,8 @@ MtrrDebugPrintAllMtrrsWorker ( return; } + VariableMtrrCount = GetVariableMtrrCountWorker (); + if (MtrrSetting != NULL) { Mtrrs = MtrrSetting; } else { @@ -2802,7 +2805,7 @@ MtrrDebugPrintAllMtrrsWorker ( DEBUG((DEBUG_CACHE, "Fixed MTRR[%02d] : %016lx\n", Index, Mtrrs->Fixed.Mtrr[Index])); } - for (Index = 0; Index < ARRAY_SIZE (Mtrrs->Variables.Mtrr); Index++) { + for (Index = 0; Index < VariableMtrrCount; Index++) { if (((MSR_IA32_MTRR_PHYSMASK_REGISTER *)&Mtrrs->Variables.Mtrr[Index].Mask)->Bits.V == 0) { // // If mask is not valid, then do not display range @@ -2829,11 +2832,11 @@ MtrrDebugPrintAllMtrrsWorker ( RangeCount = 1; MtrrLibGetRawVariableRanges ( - &Mtrrs->Variables, ARRAY_SIZE (Mtrrs->Variables.Mtrr), + &Mtrrs->Variables, VariableMtrrCount, MtrrValidBitsMask, MtrrValidAddressMask, RawVariableRanges ); MtrrLibApplyVariableMtrrs ( - RawVariableRanges, ARRAY_SIZE (RawVariableRanges), + RawVariableRanges, VariableMtrrCount, Ranges, ARRAY_SIZE (Ranges), &RangeCount ); -- 2.39.2