Re: [PATCH v5 1/2] UefiCpuPkg/SmmCpuFeaturesLib: Use global variables to replace macros

["Duran, Leo" <leo.duran@amd.com>]

> -----Original Message-----
> From: Paolo Bonzini [mailto:pbonzini@redhat.com]
> Sent: Tuesday, October 17, 2017 9:37 AM
> To: Laszlo Ersek <lersek@redhat.com>; Duran, Leo <leo.duran@amd.com>;
> edk2-devel@lists.01.org; Jiewen Yao <jiewen.yao@intel.com>
> Cc: Ruiyu Ni <ruiyu.ni@intel.com>; Michael D Kinney
> <michael.d.kinney@intel.com>; Jordan Justen <jordan.l.justen@intel.com>;
> Liming Gao <liming.gao@intel.com>
> Subject: Re: [PATCH v5 1/2] UefiCpuPkg/SmmCpuFeaturesLib: Use global
> variables to replace macros
> 
> On 17/10/2017 16:23, Laszlo Ersek wrote:
> >> For the SRAM_SAVE_STATE_MAP_OFFSET:
> >> I propose returning the value by a function in SmmCpuFeaturesLib...
> > This has crossed my mind (superficially :) ), and I support your idea.
> >
> > Paolo, can you please comment?
> 
> I don't see a reason why AMD must use a state save map that only covers the
> last 512 bytes rather than the whole 1024, even if the first half is unused...
> 
> Paolo

To me, 
- This proposed library function seems appropriate in the context of CPU features (i..e, this is not a hack)
- I'd argue having to save & restore 512 "unused" bytes per SMI is significant overheard that can be avoided.
- The proposed change is not intrusive not does it add significant amount of code.

Is there a technical reason for a "thumbs down"?
Thanks,
Leo