Re: [PATCH v1] UefiCpuPkg: Cpu feature data stored in memory may be migrated

Dong, Eric


Can you help to explain more why PeiAllocatePages does not have the problem while PeiAllocatePool has?


-----Original Message-----
From: Lou, Yun <yun.lou@...>
Sent: Wednesday, September 29, 2021 7:53 PM
Cc: Lou, Yun <yun.lou@...>; Ni, Ray <>; Dong, Eric <eric.dong@...>; Laszlo Ersek <lersek@...>; Kumar, Rahul1 <rahul1.kumar@...>
Subject: [PATCH v1] UefiCpuPkg: Cpu feature data stored in memory may be migrated


The memory allocated through "PeiAllocatePool" is located in HOB, and
in DXE phase, the HOB will be migrated to a different location.
After the migration, the data stored in the HOB stays the same, but the
address of pointer to the memory(such as the pointers in ACPI_CPU_DATA
structure) changes, which may cause "PiSmmCpuDxeSmm" driver can't find
the memory(the pointers in ACPI_CPU_DATA structure) that allocated in
"PeiRegisterCpuFeaturesLib", so use "PeiAllocatePages" to allocate
memory instead.

Signed-off-by: Jason Lou <yun.lou@...>
Cc: Ray Ni <>
Cc: Eric Dong <eric.dong@...>
Cc: Laszlo Ersek <lersek@...>
Cc: Rahul Kumar <rahul1.kumar@...>
UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
index 6e2ab79518..e9eba64914 100644
--- a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
+++ b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
@@ -153,7 +153,7 @@ CpuInitDataInitialize (
CpuFeaturesData->AcpiCpuData= AcpiCpuData;

CpuStatus = &AcpiCpuData->CpuFeatureInitData.CpuStatus;

- Location = AllocateZeroPool (sizeof (EFI_CPU_PHYSICAL_LOCATION) * NumberOfCpus);

+ Location = AllocatePages (EFI_SIZE_TO_PAGES (sizeof (EFI_CPU_PHYSICAL_LOCATION) * NumberOfCpus));

ASSERT (Location != NULL);

AcpiCpuData->CpuFeatureInitData.ApLocation = (EFI_PHYSICAL_ADDRESS)(UINTN)Location;

@@ -205,11 +205,11 @@ CpuInitDataInitialize (

// Collect valid core count in each package because not all cores are valid.


- ThreadCountPerPackage = AllocateZeroPool (sizeof (UINT32) * CpuStatus->PackageCount);

+ ThreadCountPerPackage = AllocatePages (EFI_SIZE_TO_PAGES (sizeof (UINT32) * CpuStatus->PackageCount));

ASSERT (ThreadCountPerPackage != NULL);

CpuStatus->ThreadCountPerPackage = (EFI_PHYSICAL_ADDRESS)(UINTN)ThreadCountPerPackage;

- ThreadCountPerCore = AllocateZeroPool (sizeof (UINT8) * CpuStatus->PackageCount * CpuStatus->MaxCoreCount);

+ ThreadCountPerCore = AllocatePages (EFI_SIZE_TO_PAGES (sizeof (UINT8) * CpuStatus->PackageCount * CpuStatus->MaxCoreCount));

ASSERT (ThreadCountPerCore != NULL);

CpuStatus->ThreadCountPerCore = (EFI_PHYSICAL_ADDRESS)(UINTN)ThreadCountPerCore;


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