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Date: Thu, 14 Oct 2021 08:04:38 +0200
From: "Gerd Hoffmann" <kraxel@redhat.com>
To: "Xu, Min M" <min.m.xu@intel.com>
Cc: "devel@edk2.groups.io" <devel@edk2.groups.io>,
	Brijesh Singh <brijesh.singh@amd.com>,
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Subject: Re: [edk2-devel] [PATCH V2 13/28] UefiCpuPkg: Enable Tdx support in MpInitLib
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On Thu, Oct 14, 2021 at 12:27:13AM +0000, Xu, Min M wrote:
> On October 12, 2021 6:32 PM, Gerd Hoffman wrote:
> >   Hi,
> > 
> > > +  do {
> > > +    AsmCpuid (0, &LargestEax, &Ebx, &Ecx, &Edx);
> > 
> > Again: this should use PCD.
> ConfidentialComputing PCD is set in PlatformPei. So any check of this PCD should be after PlatformPei.

Can we move that to the SEC phase?

> MpInitLib will be included in CpuMpPei. So if PCD is checked in MpInitLib, then we must assume CpuMpPei is called after PlatformPei.
> In current OVMF, CpuMpPei is called after PlatforPei. But I am not sure if it is always the case. Can we have such assumption?
> Based on above consideration, CPUID is used to probe if it is Tdx guest.

Not sure.  There are no explicit depex dependencies, so I suspect the
initialization order could change.

take care,
  Gerd