I think the commit message can have more details to help OVMF developers
understand the needs of this patch.
E.g.:
Before using SmmRelocationLib, the PiSmmCpuDxeSmm driver allocates the SMRAM
to be used for SMI handler + save state area of each processor from
Smst->AllocatePages().
With
SmmRelocationLib instance will reserve the memory from
gEfiSmmSmramMemoryGuid for the smbase relocation.
So, system must produce the gEfiSmmSmramMemoryGuid.
This patch is for the OVMF to produce the
gEfiSmmSmramMemoryGuid HOB.
Cc: Ard Biesheuvel
Cc: Jiewen Yao
Cc: Gerd Hoffmann
Cc: Ray Ni