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


Ni, Ray
 

Eric,
it's related to how pool/page memory is allocated in PEI.

The PEI pool is allocated in HOB. HOB data is migrated by DXE core to a new location. The migration guarantees the HOB data is kept but doesn't fix up the ACPI_CPU_DATA pointer that points to the HOB data.

The PEI page is allocated between Phit->FreeMemoryTop and Phit->MemoryTop. The location is not changed in DXE.

Thanks,
Ray

-----Original Message-----
From: Dong, Eric <eric.dong@...>
Sent: Wednesday, September 29, 2021 10:36 PM
To: Lou, Yun <yun.lou@...>; devel@edk2.groups.io
Cc: Ni, Ray <ray.ni@...>; Laszlo Ersek <lersek@...>; Kumar, Rahul1 <rahul1.kumar@...>
Subject: RE: [PATCH v1] UefiCpuPkg: Cpu feature data stored in memory may be migrated

Hi,

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

Thanks,
Eric

-----Original Message-----
From: Lou, Yun <yun.lou@...>
Sent: Wednesday, September 29, 2021 7:53 PM
To: devel@edk2.groups.io
Cc: Lou, Yun <yun.lou@...>; Ni, Ray <ray.ni@...>; Dong, Eric <eric.dong@...>; Laszlo Ersek
<lersek@...>; Kumar, Rahul1 <rahul1.kumar@...>
Subject: [PATCH v1] UefiCpuPkg: Cpu feature data stored in memory may be migrated

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3634

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 <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;



--
2.28.0.windows.1

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