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

["Duran, Leo" <leo.duran@amd.com>]

> -----Original Message-----
> From: Laszlo Ersek [mailto:lersek@redhat.com]
> Sent: Wednesday, February 26, 2020 11:21 AM
> To: Duran, Leo <leo.duran@amd.com>; Ni, Ray <ray.ni@intel.com>;
> devel@edk2.groups.io; Wu, Hao A <hao.a.wu@intel.com>; Fu, Siyuan
> <siyuan.fu@intel.com>
> Cc: Dong, Eric <eric.dong@intel.com>
> Subject: Re: [edk2-devel] [PATCH 0/2] UefiCpuPkg/Library: Fix bug in
> MpInitLib
> 
> 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.
[Duran, Leo] 
Great point, Laszlo.
Indeed, global makes senses in the case!
I can prepare a v2-set to incorporate that.

Thanks,
Leo
 
> 
> Thanks
> Laszlo