Re: [RFC PATCH 0/2] riscv: Adding custom CSR related Kconfig options

[Richard Henderson]

On 9/6/21 9:05 AM, Alistair Francis wrote:
> I honestly don't see a scenario where that happens. The maintenance
> overhead and confusion of changing the CPUs at build time is too high.

Yes indeed.  One qemu image should support all cpu variations at once.

> I also don't think we should need that for CSR accesses. Custom
> instructions are a whole different can of worms.

Custom instruction sets are manageable.

In general, we use separate decodetree instances, and select on them at a high level of 
translation.  We have examples of this in both target/arm/ and target/mips/ dealing with 
different ISAs.

Prod me when you get to that point.


r~