Hi,

> +  if (sizeof (UINTN) == sizeof (UINT64)) {
> +    //
> +    // Check Page5Level Support or not.
> +    //
> +    Cr4.UintN         = AsmReadCr4 ();
> +    Page5LevelSupport = (Cr4.Bits.LA57 ? TRUE : FALSE);
> +
> +    //
> +    // Check Page1G Support or not.
> +    //
> +    Page1GSupport = FALSE;
> +    AsmCpuid (CPUID_EXTENDED_FUNCTION, &RegEax, NULL, NULL, NULL);
> +    if (RegEax >= CPUID_EXTENDED_CPU_SIG) {
> +      AsmCpuid (CPUID_EXTENDED_CPU_SIG, NULL, NULL, NULL, &RegEdx.Uint32);
> +      if (RegEdx.Bits.Page1GB != 0) {
> +        Page1GSupport = TRUE;
> +      }
> +    }
> +
> +    //
> +    // Decide Paging Mode according Page5LevelSupport & Page1GSupport.
> +    //
> +    if (Page5LevelSupport) {
> +      PagingMode = Page1GSupport ? Paging5Level1GB : Paging5Level;
> +    } else {
> +      PagingMode = Page1GSupport ? Paging4Level1GB : Paging4Level;
> +    }
> +  } else {
> +    PagingMode = PagingPae;
> +  }

I'm wondering whenever CpuPageTableLib should get a function for this?
I suspect there a multiple places in edk2 which will need this
functionality ...

take care,
  Gerd