Re: [edk2-devel] [edk2-staging/RiscV64QemuVirt PATCH V4 10/34] OvmfPkg/Sec: Add RISC-V support

["Sunil V L" <sunilvl@ventanamicro.com>]

On Sat, Oct 15, 2022 at 03:50:02PM +0000, Chang, Abner wrote:
> [AMD Official Use Only - General]
> 
> Hi Sunil, this is my comment for both 9/34 and 10/34.
> The original RISC-V SecCore implementation can be used by RiscVVirt and the RISC-V platforms under edk2-platform. So my plan back to half year ago was to have SecCore under UefiCpuPkg, that would be Riscv64SecCore because current the SecCore under UeficpuPkg is hard to be leveraged. With this, one RISC-V SecCore driver can be used by RiscVVirt and RISC-V platforms. Of course we have to move some Pcds to under PCD Riscv64 arch section in UEfiCpuPkg.dec. Even through having PcdRiscVDbtFvBase(Size) for Riscv64 in UefiCpuPkg.dec makes sense to me because Device Tree is part of RISC-V processor initialization.
> Could you please take some time having this change? I think that is doable and also an ideal implementation for RISC-V.
> 
Hi Abner,

Having SEC as part of SecCoreNative in UefiCpuPkg was my original
proposal when I had sent the RFC series to discuss in the design
meeting. But if you remember, Mike provided 2 major feedbacks in the
meeting which made me to move to OvmfPkg.

1) We should not add FDF related PCD variables in common packges like
UefiCpuPkg/MdeModulePkg. OvmfPkg is the only package (ofcourse ArmVirtPkg
also currently) which is an exception to this since it actually has
platform implementation useful for CI coverage.

2) Avoid new circular dependencies. We will have to use EmbeddedPkg in
UefiCpuPkg/MdeModulePkg for FDT if we use SecCore in UefiCpuPkg.

It made sense to me and OvmfPkg already had the required PCD variables
and modules. Also, qemu virt can support different features (boot from
flash vs memory, number of flash devices etc) compared to real platforms.
So, it will be hard to use the same design for both virt machine and real
platforms. The original SecCore in edk2-platforms can be continued to be
used by real platforms. Like Ray suggested, I plan to look at
MinPlatformPkg design for real platforms in edk2-platforms repo which
will make the design flexible.

Thanks
Sunil

> Thanks
> Abner