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

["Liming Gao" <liming.gao@intel.com>]

Leo:
  Now, we enter into Hard Feature Freeze phase until edk2-stable202002 tag is created at 2020-02-28. Only critical bug fix is still allowed.

  Do you request to catch this fix into this stable tag? If yes, please work closely with UefiCpuPkg maintainers to catch the stable tag release schedule 2020-02-28.

Thanks
Liming
> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Ni, Ray
> Sent: Wednesday, February 26, 2020 3:57 PM
> To: Laszlo Ersek <lersek@redhat.com>; devel@edk2.groups.io; leo.duran@amd.com; 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
> 
> Leo,
> 
> > > BTW, reading the PlatformId MSR was already being done by MicrocodeDetect(),
> > > but it never affected AMD-based platforms as the flow never gets that far, since
> > > the Detect routine bails out early when it finds the size of the patch is zero.
> 
> You are saying that PlatformId MSR access is not performed by CPU in old code because of the zero size uCode.
> But now with Hao or Siyuan's change, the PlatformId MSR access is always performed even when there is no uCode. It sounds like a
> regression to optimization to me.
> Did you evaluate the path to avoid accessing PlatformID MSR when uCode doesn't exist? So that the API to detect AMD processor is not
> needed at all.
> 
> Thanks,
> Ray
> 
>