Re: [RFC v4 05/13] OvmfPkg/PlatformPei: Set memory encryption PCD when SEV is enabled

[Brijesh Singh <brijesh.singh@amd.com>]

On 05/11/2017 09:37 AM, Laszlo Ersek wrote:
>
> Please replace the last paragraph in the commit message with the
> following (mostly based on
> <http://mid.mail-archive.com/ec83b052-1af7-c985-35a3-0838c5943add@redhat.com>):
>
> ----
> The patch sets the memory encryption PCD. The PCD is consumed by the
> following edk2 modules, which manipulate page tables:
>
> - PEI phase modules: CapsulePei, DxeIplPeim, S3Resume2Pei.
>
>   CapsulePei is not used by OVMF. DxeIplPeim consumes the PCD at the
>   end of the PEI phase, when it builds the initial page tables for the
>   DXE core / DXE phase. S3Resume2Pei does not consume the PCD in its
>   entry point function, only when DxeIplPeim branches to the S3 resume
>   path at the end of the PEI phase, and calls S3Resume2Pei's
>   EFI_PEI_S3_RESUME2_PPI.S3RestoreConfig2() member function.
>
>   Therefore it is safe to set the PCD for these modules in PlatformPei.
>
> - DXE phase modules: BootScriptExecutorDxe, CpuDxe, PiSmmCpuDxeSmm.
>
>   They are all dispatched after the PEI phase, so setting the PCD for
>   them in PlatformPei is safe. (BootScriptExecutorDxe is launched "for
>   real" in the PEI phase during S3 resume, but it caches the PCD into a
>   static variable when its entry point is originally invoked in DXE.)
> ----
>

I will update the patch description, thanks for the write up.

-Brijesh