Re: [edk2-devel] [PATCH v1] UefiCpuPkg/PiSmmCpuDxeSmm: Use processor extended information

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

On 11/7/23 03:43, Wu, Jiaxin wrote:
> Processor extended information is filled when
> CPU_V2_EXTENDED_TOPOLOGY is set in parameter ProcessorNumber
> from GetProcessorInfo() (See commit: 1fadd18d).
> 
> This filed value is retrieved from CPUID leaf 1FH, which is
> a preferred superset to leaf 0BH.
> 
> Since Intel recommends first use the CPUID leaf 1FH instead of
> leaf 0BH, this patch change to use the processor extended
> information, which can reflect the value from CPUID leaf 1FH.
> 
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Ray Ni <ray.ni@intel.com>
> Cc: Rahul Kumar <rahul1.kumar@intel.com>
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Cc: Star Zeng <star.zeng@intel.com>
> Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com>
> ---
>  UefiCpuPkg/PiSmmCpuDxeSmm/CpuService.c | 10 ++++++++++
>  UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c  |  6 +++---
>  2 files changed, 13 insertions(+), 3 deletions(-)
> 
> diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/CpuService.c b/UefiCpuPkg/PiSmmCpuDxeSmm/CpuService.c
> index 391b64e9f2..c0485b0519 100644
> --- a/UefiCpuPkg/PiSmmCpuDxeSmm/CpuService.c
> +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/CpuService.c
> @@ -169,10 +169,20 @@ SmmAddProcessor (
>          &gSmmCpuPrivate->ProcessorInfo[Index].Location.Package,
>          &gSmmCpuPrivate->ProcessorInfo[Index].Location.Core,
>          &gSmmCpuPrivate->ProcessorInfo[Index].Location.Thread
>          );
>  
> +      GetProcessorLocation2ByApicId (
> +        (UINT32)ProcessorId,
> +        &gSmmCpuPrivate->ProcessorInfo[Index].ExtendedInformation.Location2.Package,
> +        &gSmmCpuPrivate->ProcessorInfo[Index].ExtendedInformation.Location2.Die,
> +        &gSmmCpuPrivate->ProcessorInfo[Index].ExtendedInformation.Location2.Tile,
> +        &gSmmCpuPrivate->ProcessorInfo[Index].ExtendedInformation.Location2.Module,
> +        &gSmmCpuPrivate->ProcessorInfo[Index].ExtendedInformation.Location2.Core,
> +        &gSmmCpuPrivate->ProcessorInfo[Index].ExtendedInformation.Location2.Thread
> +        );
> +
>        *ProcessorNumber                 = Index;
>        gSmmCpuPrivate->Operation[Index] = SmmCpuAdd;
>        return EFI_SUCCESS;
>      }
>    }
> diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
> index 25d058c5b9..c61562c867 100644
> --- a/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
> +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/MpService.c
> @@ -177,11 +177,11 @@ IsPackageFirstThread (
>    IN UINTN  CpuIndex
>    )
>  {
>    UINT32  PackageIndex;
>  
> -  PackageIndex =  gSmmCpuPrivate->ProcessorInfo[CpuIndex].Location.Package;
> +  PackageIndex =  gSmmCpuPrivate->ProcessorInfo[CpuIndex].ExtendedInformation.Location2.Package;
>  
>    ASSERT (mPackageFirstThreadIndex != NULL);
>  
>    //
>    // Set the value of mPackageFirstThreadIndex[PackageIndex].
> @@ -1834,12 +1834,12 @@ InitPackageFirstThreadIndexInfo (
>  
>    //
>    // Count the number of package, set to max PackageId + 1
>    //
>    for (Index = 0; Index < mNumberOfCpus; Index++) {
> -    if (PackageId < gSmmCpuPrivate->ProcessorInfo[Index].Location.Package) {
> -      PackageId = gSmmCpuPrivate->ProcessorInfo[Index].Location.Package;
> +    if (PackageId < gSmmCpuPrivate->ProcessorInfo[Index].ExtendedInformation.Location2.Package) {
> +      PackageId = gSmmCpuPrivate->ProcessorInfo[Index].ExtendedInformation.Location2.Package;
>      }
>    }
>  
>    PackageCount = PackageId + 1;
>  

The patch looks OK to me, but:

- I would like to test it with CPU hotplug (later, likely under v2), and

- I think this should be two patches.

First, the SmmAddProcessor() function should be extended just to
complete commit 1fadd18d. (BTW I highly appreciate the reference to
commit 1fadd18d; otherwise I couldn't find where the *coldplugged* CPUs'
locations were retrieved!)

Then the Package calculations should be updated separately -- mostly
because I would appreciate a concrete description in that separate
commit message why the difference matters. Clearly you have a use case
where the v1 and v2 package numbers differ, and recording that in the
commit history would be great.

Thanks
Laszlo



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