Re: [PATCH 2/3] UefiCpuPkg/CpuS3DataDxe: do not allocate useless register tables

["Laszlo Ersek" <lersek@redhat.com>]

Hi Star,

On 01/14/21 02:55, Zeng, Star wrote:
> Just think more, the change below needs a minor enhancement as below, otherwise the table will be overridden by the function's second call.

thank you for following up here -- could you or Ray please propose an
actual patch for RegisterCpuFeaturesLib, as I requested before?

Posting the patch is not necessary; I only need to fetch it from your
personal repo(s) -- you can even send me the repo / branch reference
off-list. I would include the RegisterCpuFeaturesLib patch in my v2
posting of this series.

Thanks!
Laszlo

> 
>> -----Original Message-----
>> From: Ni, Ray <ray.ni@intel.com>
>> Sent: Wednesday, January 13, 2021 4:12 PM
>> To: Zeng, Star <star.zeng@intel.com>; Laszlo Ersek <lersek@redhat.com>;
>> devel@edk2.groups.io
>> Cc: Dong, Eric <eric.dong@intel.com>; Philippe Mathieu-Daudé
>> <philmd@redhat.com>; Kumar, Rahul1 <rahul1.kumar@intel.com>
>> Subject: RE: [PATCH 2/3] UefiCpuPkg/CpuS3DataDxe: do not allocate useless
>> register tables
>>
>> Star,
>> Thanks for pointing that.
>> RegisterCpuFeaturesLib assumes [PreSmmInit]RegisterTable array is
>> allocated but CpuS3Data
>> doesn't do that.
>>
>> Can following change fix the problem?
>>
>> --- a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/RegisterCpuFeaturesLib.c
>> +++ b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/RegisterCpuFeaturesLib.c
>> @@ -937,21 +937,19 @@ GetAcpiCpuData (
>>    EFI_PROCESSOR_INFORMATION            ProcessorInfoBuffer;
>>
>>    AcpiCpuData = (ACPI_CPU_DATA *) (UINTN) PcdGet64
>> (PcdCpuS3DataAddress);
>> -  if (AcpiCpuData != NULL) {
>> -    return AcpiCpuData;
>> -  }
>> -
>> -  AcpiCpuData  = AllocatePages (EFI_SIZE_TO_PAGES (sizeof
>> (ACPI_CPU_DATA)));
>> -  ASSERT (AcpiCpuData != NULL);
>> +  if (AcpiCpuData == NULL) {
>> +    AcpiCpuData  = AllocatePages (EFI_SIZE_TO_PAGES (sizeof
>> (ACPI_CPU_DATA)));
>> +    ASSERT (AcpiCpuData != NULL);
>>
>> -  //
>> -  // Set PcdCpuS3DataAddress to the base address of the ACPI_CPU_DATA
>> structure
>> -  //
>> -  Status = PcdSet64S (PcdCpuS3DataAddress, (UINT64)(UINTN)AcpiCpuData);
>> -  ASSERT_EFI_ERROR (Status);
>> +    //
>> +    // Set PcdCpuS3DataAddress to the base address of the ACPI_CPU_DATA
>> structure
>> +    //
>> +    Status = PcdSet64S (PcdCpuS3DataAddress,
>> (UINT64)(UINTN)AcpiCpuData);
>> +    ASSERT_EFI_ERROR (Status);
>>
>> -  GetNumberOfProcessor (&NumberOfCpus, &NumberOfEnabledProcessors);
>> -  AcpiCpuData->NumberOfCpus = (UINT32)NumberOfCpus;
>> +    GetNumberOfProcessor (&NumberOfCpus,
>> &NumberOfEnabledProcessors);
>> +    AcpiCpuData->NumberOfCpus = (UINT32)NumberOfCpus;
>> +  }
>>
> 
> Add check as below here.
> 
> if (AcpiCpuData->RegisterTable == 0) {
> 
>>    //
>>    // Allocate buffer for empty RegisterTable and PreSmmInitRegisterTable
>> for all CPUs
>>
>> Thanks,
>> Ray
>>
>>> -----Original Message-----
>>> From: Zeng, Star <star.zeng@intel.com>
>>> Sent: Wednesday, January 13, 2021 3:17 PM
>>> To: Ni, Ray <ray.ni@intel.com>; Laszlo Ersek <lersek@redhat.com>;
>>> devel@edk2.groups.io
>>> Cc: Dong, Eric <eric.dong@intel.com>; Philippe Mathieu-Daudé
>>> <philmd@redhat.com>; Kumar, Rahul1 <rahul1.kumar@intel.com>; Zeng,
>> Star
>>> <star.zeng@intel.com>
>>> Subject: RE: [PATCH 2/3] UefiCpuPkg/CpuS3DataDxe: do not allocate
>> useless
>>> register tables
>>>
>>> DxeRegisterCpuFeaturesLib still has some execution sequence dependency
>> to
>>> UefiCpuPkg CpuS3DataDxe.
>>> There is ASSERT to happen at
>>>
>> https://github.com/tianocore/edk2/blob/master/UefiCpuPkg/Library/Regist
>> erC
>>> puFeaturesLib/RegisterCpuFeaturesLib.c#L1059 when CpuS3DataDxe with
>> this
>>> patch runs before DxeRegisterCpuFeaturesLib.
>>>
>>> Thanks,
>>> Star
>>> -----Original Message-----
>>> From: Ni, Ray <ray.ni@intel.com>
>>> Sent: Wednesday, January 13, 2021 2:12 PM
>>> To: Laszlo Ersek <lersek@redhat.com>; devel@edk2.groups.io
>>> Cc: Dong, Eric <eric.dong@intel.com>; Philippe Mathieu-Daudé
>>> <philmd@redhat.com>; Kumar, Rahul1 <rahul1.kumar@intel.com>; Zeng,
>> Star
>>> <star.zeng@intel.com>
>>> Subject: RE: [PATCH 2/3] UefiCpuPkg/CpuS3DataDxe: do not allocate
>> useless
>>> register tables
>>>
>>> Reviewed-by: Ray Ni <ray.ni@intel.com>
>>>
>>> (I guess you don't want to put Redhat copyright in the patch 1&2 so the
>>> copyright year is not updated.
>>> Since it's a simple change that make the logic more neat, I am ok with that.)
>>>
>>> Will you create a pull request to merge all 3 patches together?
>>>
>>>> -----Original Message-----
>>>> From: Laszlo Ersek <lersek@redhat.com>
>>>> Sent: Wednesday, January 13, 2021 3:20 AM
>>>> To: devel@edk2.groups.io
>>>> Cc: Dong, Eric <eric.dong@intel.com>; Philippe Mathieu-Daudé
>>>> <philmd@redhat.com>; Kumar, Rahul1 <rahul1.kumar@intel.com>; Ni,
>> Ray
>>>> <ray.ni@intel.com>; Zeng, Star <star.zeng@intel.com>
>>>> Subject: [PATCH 2/3] UefiCpuPkg/CpuS3DataDxe: do not allocate useless
>>>> register tables
>>>>
>>>> CpuS3DataDxe allocates the "RegisterTable" and
>> "PreSmmInitRegisterTable"
>>>> arrays in ACPI_CPU_DATA just so every processor in the system can have
>>>> its own empty register table, matched by APIC ID. This has never been
>>>> useful in practice.
>>>>
>>>> Given commit e992cc3f4859 ("UefiCpuPkg PiSmmCpuDxeSmm: Reduce
>>> SMRAM
>>>> consumption in CpuS3.c", 2021-01-11), simply leave both
>>>> "AcpiCpuData->RegisterTable" and "AcpiCpuData-
>>> PreSmmInitRegisterTable"
>>>> initialized to the zero address. This simplifies the driver, and saves
>>>> both normal RAM (boot services data type memory) and -- in
>>>> PiSmmCpuDxeSmm
>>>> -- SMRAM.
>>>>
>>>> Cc: Eric Dong <eric.dong@intel.com>
>>>> Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
>>>> Cc: Rahul Kumar <rahul1.kumar@intel.com>
>>>> Cc: Ray Ni <ray.ni@intel.com>
>>>> Cc: Star Zeng <star.zeng@intel.com>
>>>> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3159
>>>> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
>>>> ---
>>>>
>>>> Notes:
>>>>     Tested by temporarily replacing OvmfPkgPkg/CpuS3DataDxe in the
>>>> OVMF
>>>> IA32
>>>>     and IA32X64 platforms with this driver -- this driver works OK in OVMF
>>>>     as long as no CPUs are hot-plugged.
>>>>
>>>>  UefiCpuPkg/CpuS3DataDxe/CpuS3Data.c | 32 --------------------
>>>>  1 file changed, 32 deletions(-)
>>>>
>>>> diff --git a/UefiCpuPkg/CpuS3DataDxe/CpuS3Data.c
>>>> b/UefiCpuPkg/CpuS3DataDxe/CpuS3Data.c
>>>> index 2be335d91903..078af36cfb41 100644
>>>> --- a/UefiCpuPkg/CpuS3DataDxe/CpuS3Data.c
>>>> +++ b/UefiCpuPkg/CpuS3DataDxe/CpuS3Data.c
>>>> @@ -165,10 +165,6 @@ CpuS3DataInitialize (
>>>>    UINTN                      NumberOfCpus;
>>>>    UINTN                      NumberOfEnabledProcessors;
>>>>    VOID                       *Stack;
>>>> -  UINTN                      TableSize;
>>>> -  CPU_REGISTER_TABLE         *RegisterTable;
>>>> -  UINTN                      Index;
>>>> -  EFI_PROCESSOR_INFORMATION  ProcessorInfoBuffer;
>>>>    UINTN                      GdtSize;
>>>>    UINTN                      IdtSize;
>>>>    VOID                       *Gdt;
>>>> @@ -255,34 +251,6 @@ CpuS3DataInitialize (
>>>>      AcpiCpuData->PreSmmInitRegisterTable = OldAcpiCpuData-
>>>>> PreSmmInitRegisterTable;
>>>>      AcpiCpuData->ApLocation              = OldAcpiCpuData->ApLocation;
>>>>      CopyMem (&AcpiCpuData->CpuStatus, &OldAcpiCpuData->CpuStatus,
>>>> sizeof (CPU_STATUS_INFORMATION));
>>>> -  } else {
>>>> -    //
>>>> -    // Allocate buffer for empty RegisterTable and
>> PreSmmInitRegisterTable
>>> for
>>>> all CPUs
>>>> -    //
>>>> -    TableSize = 2 * NumberOfCpus * sizeof (CPU_REGISTER_TABLE);
>>>> -    RegisterTable = (CPU_REGISTER_TABLE *)AllocateZeroPages
>> (TableSize);
>>>> -    ASSERT (RegisterTable != NULL);
>>>> -
>>>> -    for (Index = 0; Index < NumberOfCpus; Index++) {
>>>> -      Status = MpServices->GetProcessorInfo (
>>>> -                           MpServices,
>>>> -                           Index,
>>>> -                           &ProcessorInfoBuffer
>>>> -                           );
>>>> -      ASSERT_EFI_ERROR (Status);
>>>> -
>>>> -      RegisterTable[Index].InitialApicId      =
>>>> (UINT32)ProcessorInfoBuffer.ProcessorId;
>>>> -      RegisterTable[Index].TableLength        = 0;
>>>> -      RegisterTable[Index].AllocatedSize      = 0;
>>>> -      RegisterTable[Index].RegisterTableEntry = 0;
>>>> -
>>>> -      RegisterTable[NumberOfCpus + Index].InitialApicId      =
>>>> (UINT32)ProcessorInfoBuffer.ProcessorId;
>>>> -      RegisterTable[NumberOfCpus + Index].TableLength        = 0;
>>>> -      RegisterTable[NumberOfCpus + Index].AllocatedSize      = 0;
>>>> -      RegisterTable[NumberOfCpus + Index].RegisterTableEntry = 0;
>>>> -    }
>>>> -    AcpiCpuData->RegisterTable           =
>>>> (EFI_PHYSICAL_ADDRESS)(UINTN)RegisterTable;
>>>> -    AcpiCpuData->PreSmmInitRegisterTable =
>>>> (EFI_PHYSICAL_ADDRESS)(UINTN)(RegisterTable + NumberOfCpus);
>>>>    }
>>>>
>>>>    //
>>>> --
>>>> 2.19.1.3.g30247aa5d201
>>>>
>