Re: [edk2-devel] [PATCH 0/2] UefiCpuPkg/Library: Fix bug in MpInitLib

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

On 02/26/20 16:46, Duran, Leo wrote:
> BTW,
> 
> I also considered adding a flag to CPU_MP_DATA to make the usage of PlatformId a bit more explicit.
> E.g., something like CpuMpData->CpuData[ProcessorNumber].IsValidPlatformId... So the init code would look like this:
> 
>   //
>   // NOTE: PlatformId is not relevant on AMD platforms.
>   //
>   if (StandardSignatureIsAuthenticAMD ()) {
>     CpuMpData->CpuData[ProcessorNumber].IsValidPlatformId = FALSE;
>   else {
>     PlatformIdMsr.Uint64 = AsmReadMsr64 (MSR_IA32_PLATFORM_ID);
>     CpuMpData->CpuData[ProcessorNumber].PlatformId = (UINT8)PlatformIdMsr.Bits.PlatformId;
>     CpuMpData->CpuData[ProcessorNumber].IsValidPlatformId = TRUE;
>   }
> 
> This way "IsValidPlatformId" could be checked prior to using "PlatformId".
> Anyway, that seemed a bit overkill, so I opted against it... thoughts?

I think a global flag is justified; in the above approach,
"IsValidPlatformId" would not vary across "ProcessorNumber", so it does
look like useless generality.

Thanks
Laszlo