Re: [Qemu-devel] RISC-V: Vector && DSP Extension

[Aleksandar Markovic]

On Thu, Aug 8, 2019 at 11:52 AM liuzhiwei <address@hidden> wrote:

> Hi all,
>
>     My workmate  and I have been working on Vector & Dsp extension, and
> I'd like to share develop status  with folks.
>
>     The spec references for  Vector extension is riscv-v-spec-0.7.1, and
> riscv-p-spec-0.5 for DSP extension.


Hello, Liu.

I will not answer your questions directly, however I want to bring to you
and others another perspective on this situation.

First, please provide the link to the specifications. Via Google, I found
that "riscv-v-spec-0.7.1" is titled "Working draft of the proposed RISC-V V
vector extension". I could not find "riscv-p-spec-0.5".

I am not sure what the QEMU policy towards "working draft proposal" type of
specification is. Peter, can you perhaps clarify that or any other related
issue?

I would advice some caution in these cases. The major issue is backward
compatibility, but there are other issues too. Let's say, fairness. If we
let emulation of a component based on a "working draft proposal" be
integrated into QEMU, this will set a precedent, and many other developer
would rightfully ask for their contributions based on drafts to be
integrated into QEMU. Our policy should be as equal as possible to all
contribution, large or small, riscv or alpha, cpu or device, tcg or kvm -
in my honest opinion. QEMU upstream should not be a collecting place for
all imaginable experimentations, certain criteria on what is appropriate
for upstreaming exist and must continue to exist.

Yours,
Aleksandar




> The code of vector extension is
> ready and under testing,  the first patch will be sent about two weeks
> later. After that we will forward working on DSP extension, and send the
> first patch in middle  October.
>
>      Could the maintainers  tell me whether the specs referenced are
> appropriate? Is anyone working on these extensions?  I'd like to get
> your status, and maybe discuss questions and work togather.
>
> Best Regards
>
> LIU Zhiwei
>
>
>
>