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UefiCpuPkg/MtrrLib: Add internal function MtrrLibIsMtrrSupported. 

Add internal function MtrrLibIsMtrrSupported and
update IsMtrrSupported to call the new internal function.

Signed-off-by: Ray Ni <ray.ni@intel.com>

Cc: Eric Dong <eric.dong@intel.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
This commit is contained in:
Ray Ni 2022-09-29 12:02:56 +08:00 committed by mergify[bot]
parent 4ddd8ac3a2
commit bf03c4a52a
1 changed files with 60 additions and 23 deletions
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83
UefiCpuPkg/Library/MtrrLib/MtrrLib.c
View File

@ -5,7 +5,7 @@
Most of services in this library instance are suggested to be invoked by BSP only,
except for MtrrSetAllMtrrs() which is used to sync BSP's MTRR setting to APs.
Copyright (c) 2008 - 2020, Intel Corporation. All rights reserved.<BR>
Copyright (c) 2008 - 2023, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
@ -140,6 +140,64 @@ MtrrDebugPrintAllMtrrsWorker (
IN MTRR_SETTINGS *MtrrSetting
);
/**
Return whether MTRR is supported.
@param[out] FixedMtrrSupported Return whether fixed MTRR is supported.
@param[out] VariableMtrrCount Return the max number of variable MTRRs.
@retval TRUE MTRR is supported when either fixed MTRR is supported or max number
of variable MTRRs is not 0.
@retval FALSE MTRR is not supported when both fixed MTRR is not supported and max
number of variable MTRRs is 0.
**/
BOOLEAN
MtrrLibIsMtrrSupported (
OUT BOOLEAN *FixedMtrrSupported OPTIONAL,
OUT UINT32 *VariableMtrrCount OPTIONAL
)
{
CPUID_VERSION_INFO_EDX Edx;
MSR_IA32_MTRRCAP_REGISTER MtrrCap;
//
// Check CPUID(1).EDX[12] for MTRR capability
//
AsmCpuid (CPUID_VERSION_INFO, NULL, NULL, NULL, &Edx.Uint32);
if (Edx.Bits.MTRR == 0) {
if (FixedMtrrSupported != NULL) {
*FixedMtrrSupported = FALSE;
}
if (VariableMtrrCount != NULL) {
*VariableMtrrCount = 0;
}
return FALSE;
}
//
// Check the number of variable MTRRs and determine whether fixed MTRRs exist.
// If the count of variable MTRRs is zero and there are no fixed MTRRs,
// then return false
//
MtrrCap.Uint64 = AsmReadMsr64 (MSR_IA32_MTRRCAP);
ASSERT (MtrrCap.Bits.VCNT <= ARRAY_SIZE (((MTRR_VARIABLE_SETTINGS *)0)->Mtrr));
if (FixedMtrrSupported != NULL) {
*FixedMtrrSupported = (BOOLEAN)(MtrrCap.Bits.FIX == 1);
}
if (VariableMtrrCount != NULL) {
*VariableMtrrCount = MtrrCap.Bits.VCNT;
}
if ((MtrrCap.Bits.VCNT == 0) && (MtrrCap.Bits.FIX == 0)) {
return FALSE;
}
return TRUE;
}
/**
Worker function returns the variable MTRR count for the CPU.
@ -2847,28 +2905,7 @@ IsMtrrSupported (
VOID
)
{
CPUID_VERSION_INFO_EDX Edx;
MSR_IA32_MTRRCAP_REGISTER MtrrCap;
//
// Check CPUID(1).EDX[12] for MTRR capability
//
AsmCpuid (CPUID_VERSION_INFO, NULL, NULL, NULL, &Edx.Uint32);
if (Edx.Bits.MTRR == 0) {
return FALSE;
}
//
// Check number of variable MTRRs and fixed MTRRs existence.
// If number of variable MTRRs is zero, or fixed MTRRs do not
// exist, return false.
//
MtrrCap.Uint64 = AsmReadMsr64 (MSR_IA32_MTRRCAP);
if ((MtrrCap.Bits.VCNT == 0) || (MtrrCap.Bits.FIX == 0)) {
return FALSE;
}
return TRUE;
return MtrrLibIsMtrrSupported (NULL, NULL);
}
/**