Re: [RFC PATCH 0/5] Deprecate/rename singlestep command line option

[Markus Armbruster <armbru@redhat.com>]

Peter Maydell <peter.maydell@linaro.org> writes:

> On Tue, 7 Feb 2023 at 15:56, Markus Armbruster <armbru@redhat.com> wrote:
>> > (3) what should we do about the HMP StatusInfo object?
>> >     I'm not sure how we handle compatibility for HMP.
>>
>> Uh, you mean *QMP*, don't you?
>
> Yes.
>
>> As you wrote above, StatusInfo is returned by query-status, which is a
>> stable interface.  Changes to members therefore require the usual
>> deprecation grace period.  We'd add a new member with a sane name, and
>> deprecate the old one.
>
> Question: is it worth creating a new 'one-insn-per-tb' member at all,
> or should we instead just make the 'singlestep' member optional and
> then stop emitting it (and as a corollary stop reporting it in
> HMP 'info status')? It seems kind of weird that we surface this
> specific slightly esoteric accelerator property and only this one
> in the StatusInfo struct.

Making a mandatory member of QMP output optional is an incompatible
change.  Not necessary here.

If you think the value is not worth reporting, deprecate @singlestep in
QMP, and drop it after a grace period.  You can drop it from HMP right
away, or together with QMP.