From 9730ca2d50e25ba114588ff72be1402333245cba Mon Sep 17 00:00:00 2001 From: Ruiyu Ni Date: Mon, 8 Jan 2018 18:11:39 +0800 Subject: [PATCH] UefiCpuPkg/MtrrLib: Fix bug that may calculate wrong MTRR result Code forgot to initialize the optional weight between adjacent vertices. It caused wrong MTRR result was calculated for some memory settings. The logic was incorrectly removed when converting from POC code. The patch adds back the initialization. Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Ruiyu Ni Reviewed-by: Eric Dong (cherry picked from commit ffb4c72d7b637d4ac377fc7da7575069f15c288e) --- UefiCpuPkg/Library/MtrrLib/MtrrLib.c | 37 +++++++++++++++++++--------- 1 file changed, 25 insertions(+), 12 deletions(-) diff --git a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c index 95a631315b..7847286805 100644 --- a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c +++ b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c @@ -1583,20 +1583,33 @@ MtrrLibCalculateMtrrs ( Vector[VectorCount - 1].Address = Base1; Weight = (UINT8 *) &Vector[VectorCount]; - // - // Set mandatory weight between any vector to max - // Set optional weight and between any vector and self->self to 0 - // E.g.: - // 00 FF FF FF - // 00 00 FF FF - // 00 00 00 FF - // 00 00 00 00 - // for (VectorIndex = 0; VectorIndex < VectorCount; VectorIndex++) { + // + // Set optional weight between vertices and self->self to 0 + // SetMem (&Weight[M(VectorIndex, 0)], VectorIndex + 1, 0); - if (VectorIndex != VectorCount - 1) { - Weight[M (VectorIndex, VectorIndex + 1)] = (DefaultType == Vector[VectorIndex].Type) ? 0 : 1; - SetMem (&Weight[M (VectorIndex, VectorIndex + 2)], VectorCount - VectorIndex - 2, MAX_WEIGHT); + // + // Set mandatory weight between vectors to MAX_WEIGHT + // + SetMem (&Weight[M (VectorIndex, VectorIndex + 1)], VectorCount - VectorIndex - 1, MAX_WEIGHT); + + // Final result looks like: + // 00 FF FF FF + // 00 00 FF FF + // 00 00 00 FF + // 00 00 00 00 + } + + // + // Set mandatory weight and optional weight for adjacent vertices + // + for (VectorIndex = 0; VectorIndex < VectorCount - 1; VectorIndex++) { + if (Vector[VectorIndex].Type != DefaultType) { + Weight[M (VectorIndex, VectorIndex + 1)] = 1; + Weight[O (VectorIndex, VectorIndex + 1)] = 0; + } else { + Weight[M (VectorIndex, VectorIndex + 1)] = 0; + Weight[O (VectorIndex, VectorIndex + 1)] = 1; } }