Re: [PATCH 00/10] Introduce TDVF Config-B (basic) in OvmfPkg

["Min Xu" <min.m.xu@intel.com>]

On December 15, 2021 6:42 PM, Gerd Hoffmann wrote:
> > Patch 2/3:
> > This patch-set leverage the PrePiLib and MemoryAllocationLib in
> > EmbeddedPkg. Some new funtions are added to meet the Tdvf Config-B
> > requirement.
> 
> Care to explain why this is needed?  How is tdvf different from other pei-less
> platforms?  Could we just place DXEFV directly in the firmware image, without
> wrapping it into FVMAIN_COMPACT for compression?
PrePiLib and MemoryAllocationLib in EmbeddedPkg can meet most of the requirement of TDVF Config-B, for example, the hob list functions, fw volume related functions, memory allocation functions, etc. 
But there are still TDVF specific function missed. For Example, EmbeddedPkg assumes the compressed section contains only one FV (DXE FV), so FfsProcessFvFile () can only handle this situation. But in TDVF's image, the compressed section contains 2 FV (PeiFV and DxeFV, this is because of *ONE BINARY* requirement). So FfsProcessFvFileEx () is added to handle this case.
I have to say, *ONE BINARY* requirement restricts us from changing the OVMF image layout, otherwise the current code (legacy guest, SEV guest, etc) will break.

Thanks
Min