[PATCH 0/2] Quality improvement of MtrrLib

[PATCH 0/2] Quality improvement of MtrrLib

[Ruiyu Ni]

The patch set fixes two bugs in MtrrLib.
With the two fixes, randomly generated 10000000 memory settings
can be set correctly.

Ruiyu Ni (2):
  UefiCpuPkg/MtrrLib: Fix a MTRR calculation bug
  UefiCpuPkg/MtrrLib: Fix an assertion bug

 UefiCpuPkg/Library/MtrrLib/MtrrLib.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

-- 
2.15.1.windows.2

[PATCH 1/2] UefiCpuPkg/MtrrLib: Fix a MTRR calculation bug

[Ruiyu Ni]

80                   A8   B0   B8   C0
+----------WB--------+-UC-+-WT-+-WB-+

For above memory settings, current code caused the final MTRR
settings miss [A8, B0, UC] when default memory type is UC.

The root cause is the code only checks the mandatory weight
between A8 to B0, but skips to check the optional weight.
The patch fixes this issue.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
---
 UefiCpuPkg/Library/MtrrLib/MtrrLib.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
index fafa15fd63..768d4d5cff 100644
--- a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
+++ b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
@@ -47,7 +47,7 @@ typedef struct {
   UINT64                 Address;
   UINT64                 Alignment;
   UINT64                 Length;
-  UINT8                  Type : 7;
+  MTRR_MEMORY_CACHE_TYPE Type : 7;
 
   //
   // Temprary use for calculating the best MTRR settings.
@@ -1429,7 +1429,7 @@ MtrrLibCalculateSubtractivePath (
           while (SubStart != SubStop) {
             Status = MtrrLibAppendVariableMtrr (
               Mtrrs, MtrrCapacity, MtrrCount,
-              Vertices[SubStart].Address, Vertices[SubStart].Length, (MTRR_MEMORY_CACHE_TYPE) Vertices[SubStart].Type
+              Vertices[SubStart].Address, Vertices[SubStart].Length, Vertices[SubStart].Type
             );
             if (RETURN_ERROR (Status)) {
               return Status;
@@ -1450,10 +1450,11 @@ MtrrLibCalculateSubtractivePath (
             Pre = Vertices[Cur].Previous;
             SubStop = Pre;
 
-            if (Weight[M (Pre, Cur)] != 0) {
+            if (Weight[M (Pre, Cur)] + Weight[O (Pre, Cur)] != 0) {
               Status = MtrrLibAppendVariableMtrr (
                 Mtrrs, MtrrCapacity, MtrrCount,
-                Vertices[Pre].Address, Vertices[Cur].Address - Vertices[Pre].Address, LowestPrecedentType
+                Vertices[Pre].Address, Vertices[Cur].Address - Vertices[Pre].Address,
+                (Pre != Cur - 1) ? LowestPrecedentType : Vertices[Pre].Type
               );
               if (RETURN_ERROR (Status)) {
                 return Status;
-- 
2.15.1.windows.2

[PATCH 2/2] UefiCpuPkg/MtrrLib: Fix an assertion bug

[Ruiyu Ni]

0                     40          f0         100
+---WT--+--UC--+--WT--+-----WB----+----UC----+

When calculating the shortest path from 0 to 100, the
MtrrLibCalculateLeastMtrrs() is called to update the
Vertices.Previous.
When calculating the shortest path from 0 to 40,
MtrrLibCalculateLeastMtrrs() is called recursively to update the
Vertices.Previous.
The second call corrupt the Previous value that will be used
later.
The patch removes the code that corrupts Previous.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
---
 UefiCpuPkg/Library/MtrrLib/MtrrLib.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
index 768d4d5cff..30b0df030b 100644
--- a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
+++ b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
@@ -1171,7 +1171,6 @@ MtrrLibCalculateLeastMtrrs (
 
   for (Index = Start; Index <= Stop; Index++) {
     Vertices[Index].Visited = FALSE;
-    Vertices[Index].Previous = VertexCount;
     Mandatory = Weight[M(Start,Index)];
     Vertices[Index].Weight = Mandatory;
     if (Mandatory != MAX_WEIGHT) {
-- 
2.15.1.windows.2

Re: [PATCH 0/2] Quality improvement of MtrrLib

[Dong, Eric]

Reviewed-by: Eric Dong <eric.dong@intel.com>

-----Original Message-----
From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Ruiyu Ni
Sent: Wednesday, January 10, 2018 1:40 PM
To: edk2-devel@lists.01.org
Subject: [edk2] [PATCH 0/2] Quality improvement of MtrrLib

The patch set fixes two bugs in MtrrLib.
With the two fixes, randomly generated 10000000 memory settings can be set correctly.

Ruiyu Ni (2):
  UefiCpuPkg/MtrrLib: Fix a MTRR calculation bug
  UefiCpuPkg/MtrrLib: Fix an assertion bug

 UefiCpuPkg/Library/MtrrLib/MtrrLib.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

--
2.15.1.windows.2

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