[edk2-devel] [PATCH v3 1/1] UefiCpuPkg: Clean up save state boundary checks and comments.

[Mark Wilson]

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2956

In functions ReadSaveStateRegisterByIndex and WriteSaveStateRegister:
* check width > 4 instead of >= 4 when writing upper 32 bytes.
  - This improves the code but will not affect functionality.

Cc: Eric Dong <eric.dong at intel.com>
Cc: Ray Ni <ray.ni at intel.com>
Signed-off-by: Mark Wilson <Mark.Wilson at amd.com>
---
 UefiCpuPkg/PiSmmCpuDxeSmm/SmramSaveState.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/SmramSaveState.c b/UefiCpuPkg/PiSmmCpuDxeSmm/SmramSaveState.c
index 661cc51f361a..0ab5e1ba0f14 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/SmramSaveState.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/SmramSaveState.c
@@ -315,12 +315,12 @@ ReadSaveStateRegisterByIndex (
     }

 

     //

-    // Write lower 32-bits of return buffer

+    // Write at most 4 of the lower bytes of the return buffer

     //

     CopyMem(Buffer, (UINT8 *)CpuSaveState + mSmmCpuWidthOffset[RegisterIndex].Offset64Lo, MIN(4, Width));

-    if (Width >= 4) {

+    if (Width > 4) {

       //

-      // Write upper 32-bits of return buffer

+      // Write at most 4 of the upper bytes of the return buffer

       //

       CopyMem((UINT8 *)Buffer + 4, (UINT8 *)CpuSaveState + mSmmCpuWidthOffset[RegisterIndex].Offset64Hi, Width - 4);

     }

@@ -539,12 +539,12 @@ WriteSaveStateRegister (
     }

 

     //

-    // Write lower 32-bits of SMM State register

+    // Write at most 4 of the lower bytes of SMM State register

     //

     CopyMem((UINT8 *)CpuSaveState + mSmmCpuWidthOffset[RegisterIndex].Offset64Lo, Buffer, MIN (4, Width));

-    if (Width >= 4) {

+    if (Width > 4) {

       //

-      // Write upper 32-bits of SMM State register

+      // Write at most 4 of the upper bytes of SMM State register

       //

       CopyMem((UINT8 *)CpuSaveState + mSmmCpuWidthOffset[RegisterIndex].Offset64Hi, (UINT8 *)Buffer + 4, Width - 4);

     }

-- 
2.28.0.windows.1



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