Re: [PATCH V2 09/10] OvmfPkg: Update DxeAcpiTimerLib to read HostBridgeDevId in PlatformInfoHob

["Gerd Hoffmann" <kraxel@redhat.com>]

On Tue, Feb 08, 2022 at 08:20:20AM +0000, Xu, Min M wrote:
> On January 27, 2022 9:49 PM, Gerd Hoffmann wrote:
> > > +  EFI_HOB_GUID_TYPE      *GuidHob;
> > > +  EFI_HOB_PLATFORM_INFO  *PlatformInfo = NULL;
> > 
> > >    // Query Host Bridge DID to determine platform type
> > > +  // Tdx guest stores the HostBridgePciDevId in a GuidHob.
> > > +  // So we first check if this HOB exists
> > 
> > Hmm, wouldn't it be better to create and use the PlatformInfo for both PEI-
> > based and PEI-less boot?
> > 
> > > -  HostBridgeDevId = PcdGet16 (PcdOvmfHostBridgePciDevId);
> > > +  GuidHob = GetFirstGuidHob (&gUefiOvmfPkgTdxPlatformGuid);  if
> > > + (GuidHob != NULL) {
> > > +    PlatformInfo    = (EFI_HOB_PLATFORM_INFO *)GET_GUID_HOB_DATA
> > (GuidHob);
> > > +    HostBridgeDevId = PlatformInfo->HostBridgePciDevId;  } else {
> > > +    HostBridgeDevId = PcdGet16 (PcdOvmfHostBridgePciDevId);  }
> > 
> > We would not need that kind of checks in the first place then.
> > 
> As we agreed at the first stage, only OvmfPkg/PlatformPei will be refactored with PlatformInitLib. 
> OvmfPkg/Bhyve/PlatformPei and OvmfPkg/XenPlatformPei will be refactored in the future. HostBridgeDevId is set to PcdOvmfHostBridgePciDevId in these 2 platforms.
> So we have to check both EFI_HOB_PLATFORM_INFO and PcdOvmfHostBridgePciDevId.

Ok.  Can you add a comment explaining this?

thanks,
  Gerd