Re: [edk2-devel] [PATCH V3 2/2] OvmfPkg: Update CcProbeLib to DxeCcProbeLib

["Min Xu" <min.m.xu@intel.com>]

On August 26, 2022 1:23 PM, Gerd Hoffmann wrote:
>   Hi,
> 
> > In DxeCcProbeLib we cache the GuestType in Ovmf work area in first-call.
> > After that the Guest type is returned with the cached value. So that
> > we don't need to worry about the access to Ovmf work area after
> > ExitBootService.
> 
> This only works in case the first call is early enough.
> Better use a CONSTRUCTOR instead.
> 
Thanks for reminder.
There is another situation that the first call of DxeCcProbeLib is earlier than its CONSTRUCTOR.
For example, in MdeModulePkg/Core/Dxe/DxeMain, BaseDebugLibSerialPortConstructor is called before DxeCcProbeLibConstructor. While CcProbe () is called in BaseDebugLibSerialPortConstructor.
So I would like to read the Cc guest type in both CONSTRUCTOR and CcProbe.

ProcessLibraryConstructorList (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EFI_STATUS  Status;

  Status = BaseDebugLibSerialPortConstructor ();
  ASSERT_RETURN_ERROR (Status);

  Status = DxeCcProbeLibConstructor ();
  ASSERT_RETURN_ERROR (Status);
  ...
  ...
}

Thanks
Min