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authorRuiyu Ni <ruiyu.ni@intel.com>2018-01-18 14:13:32 +0800
committerRuiyu Ni <ruiyu.ni@intel.com>2018-01-24 11:14:09 +0800
commit15bb108d5f9d9167b4c42f8c003c21b2c90c329e (patch)
tree701e1adb65319be21fb0c6fddd4612388a6d9ac0 /UefiCpuPkg
parent0bc9d2d64a3569edf2de8035909904312b004cfb (diff)
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UefiCpuPkg/MtrrLib: Add comments to recommend to use batch-set API
MtrrSetMemoryAttributesInMtrrSettings() is a batch-set API. When setting multiple ranges of memory attributes, the single-set API (MtrrSetMemoryAttributeInMtrrSettings and MtrrSetMemoryAttribute) may fail, but batch-set API may succeed. Add comments to recommend caller to use batch-set API when setting multiple ranges. Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com> Reviewed-by: Ming Shao <ming.shao@intel.com> (cherry picked from commit bc6a8b78aa77cf63aa896c5dba0d948d4eebfa73)
Diffstat (limited to 'UefiCpuPkg')
-rw-r--r--UefiCpuPkg/Include/Library/MtrrLib.h10
-rw-r--r--UefiCpuPkg/Library/MtrrLib/MtrrLib.c10
2 files changed, 20 insertions, 0 deletions
diff --git a/UefiCpuPkg/Include/Library/MtrrLib.h b/UefiCpuPkg/Include/Library/MtrrLib.h
index d56f1057e1..f82c27ea0c 100644
--- a/UefiCpuPkg/Include/Library/MtrrLib.h
+++ b/UefiCpuPkg/Include/Library/MtrrLib.h
@@ -157,6 +157,11 @@ GetFirmwareVariableMtrrCount (
@retval RETURN_OUT_OF_RESOURCES There are not enough system resources to
modify the attributes of the memory
resource range.
+ Multiple memory range attributes setting by calling this API multiple
+ times may fail with status RETURN_OUT_OF_RESOURCES. It may not mean
+ the number of CPU MTRRs are too small to set such memory attributes.
+ Pass the multiple memory range attributes to one call of
+ MtrrSetMemoryAttributesInMtrrSettings() may succeed.
@retval RETURN_BUFFER_TOO_SMALL The fixed internal scratch buffer is too small for MTRR calculation.
Caller should use MtrrSetMemoryAttributesInMtrrSettings() to specify
external scratch buffer.
@@ -354,6 +359,11 @@ MtrrGetDefaultMemoryType (
BaseAddress and Length cannot be modified.
@retval RETURN_OUT_OF_RESOURCES There are not enough system resources to modify the attributes of
the memory resource range.
+ Multiple memory range attributes setting by calling this API multiple
+ times may fail with status RETURN_OUT_OF_RESOURCES. It may not mean
+ the number of CPU MTRRs are too small to set such memory attributes.
+ Pass the multiple memory range attributes to one call of
+ MtrrSetMemoryAttributesInMtrrSettings() may succeed.
@retval RETURN_BUFFER_TOO_SMALL The fixed internal scratch buffer is too small for MTRR calculation.
Caller should use MtrrSetMemoryAttributesInMtrrSettings() to specify
external scratch buffer.
diff --git a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
index 408de72825..611da362f3 100644
--- a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
+++ b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
@@ -2464,6 +2464,11 @@ MtrrSetMemoryAttributesInMtrrSettings (
BaseAddress and Length cannot be modified.
@retval RETURN_OUT_OF_RESOURCES There are not enough system resources to modify the attributes of
the memory resource range.
+ Multiple memory range attributes setting by calling this API multiple
+ times may fail with status RETURN_OUT_OF_RESOURCES. It may not mean
+ the number of CPU MTRRs are too small to set such memory attributes.
+ Pass the multiple memory range attributes to one call of
+ MtrrSetMemoryAttributesInMtrrSettings() may succeed.
@retval RETURN_BUFFER_TOO_SMALL The fixed internal scratch buffer is too small for MTRR calculation.
Caller should use MtrrSetMemoryAttributesInMtrrSettings() to specify
external scratch buffer.
@@ -2525,6 +2530,11 @@ MtrrSetMemoryAttributeInMtrrSettings (
@retval RETURN_OUT_OF_RESOURCES There are not enough system resources to
modify the attributes of the memory
resource range.
+ Multiple memory range attributes setting by calling this API multiple
+ times may fail with status RETURN_OUT_OF_RESOURCES. It may not mean
+ the number of CPU MTRRs are too small to set such memory attributes.
+ Pass the multiple memory range attributes to one call of
+ MtrrSetMemoryAttributesInMtrrSettings() may succeed.
@retval RETURN_BUFFER_TOO_SMALL The fixed internal scratch buffer is too small for MTRR calculation.
Caller should use MtrrSetMemoryAttributesInMtrrSettings() to specify
external scratch buffer.