Re: [PATCH 00/16] Add Multi-Core Debug (MCD) API support

[Markus Armbruster <armbru@redhat.com>]

Alex Bennée <alex.bennee@linaro.org> writes:

> Markus Armbruster <armbru@redhat.com> writes:
>
>> Mario Fleischmann <mario.fleischmann@lauterbach.com> writes:
>>
>>> Apologies for the line wrapping in yesterday's answer. Should be fixed now.
>>>
>>> On 08.04.2025 09:00, Markus Armbruster wrote:

[...]

>>>> What about providing the MCD interface as a separate QMP-like protocol?
>>>> It gets its own QAPI schema, just like for qemu-ga.  Simplifies
>>>> compiling it out when not needed.
>>>>
>>>> It gets its own socket, just like the GDB stub.  Might reduce
>>>> interference between debugging and QMP.
>>>> 
>>>> Thoughts?  Alex, Philippe, care to chime in?
>>>
>>> Sound reasonable to me. Keeping in mind the size of generated QAPI code,
>>> an option to `./configure [...] --enable-mcd` is definitely advisable.
>>
>> Alex, Philippe?
>
> When I spoke to Mario at DVCon last year I liked the idea of re-using
> QMP instead of inventing yet another RPC interface for QEMU. QMP
> certainly has nicer properties than the gdbstub which has a very
> "organic" and "serial" feel to it.
>
> Are you suggesting we re-use the machinery but use an entirely separate
> socket with just the MCD namespace in it? I don't see that being a
> problem as long as we can test it properly in the CI.

Yes.

"Keep them separate" is only a gut feeling, though.  While I pay
attention to my gut feelings, I know they can be wrong.  I am soliciting
opinions.