Gerd,
The S3 path has been 64bit ready.
Can you check if OVMF pei64 image can do s3?

At least internally in some real platform we tested s3 flow with 64bit PEI.

Thanks,
Ray

thanks,
ray
From: Gerd Hoffmann <kraxel@redhat.com>
Sent: Monday, May 22, 2023 8:06:46 PM
To: Ard Biesheuvel <ardb@kernel.org>
Cc: edk2-devel-groups-io <devel@edk2.groups.io>; Ni, Ray <ray.ni@intel.com>; Yao, Jiewen <jiewen.yao@intel.com>; Laszlo Ersek <lersek@redhat.com>; Taylor Beebe <t@taylorbeebe.com>; Oliver Smith-Denny <osd@smith-denny.com>
Subject: Re: managing memory attributes in PEI
 
> So my questions are:
> - do we need to retain mixed IA32 / X64 support, and if so, why? (I
> think it is related to SMM emulation but I need someone to confirm
> this)

Yes, it's SMM related.  S3 suspend in SMM-enabled builds requires
32bit PEI.

Intel seems to be working on removing the IA32 dependency, by adding
full X64 support to various places in the code base.  There have been
numerous patch sets on the list over the last months, some of them
are merged meanwhile.  As far I know the patch series addressing the
suspend problem is not yet merged (Ray, Jiewen, please correct me if
I'm wrong).

So, right now we still need that, but I expect that to change in near
future.

take care,
  Gerd