Re: [PATCH 0/9] add LOG_UNSUPP log type + mark hcalls as unsupp

[Peter Maydell]

On Mon, 7 Mar 2022 at 19:19, Daniel Henrique Barboza
<danielhb413@gmail.com> wrote:
>
> Hi,
>
> I got a lot of noise trying to debug an AIX guest in a pseries machine when 
> running with
> '-d unimp'. The reason is that there is no distinction between features
> (in my case, hypercalls) that are unimplemented because we never considered,
> versus features that we made a design choice not to implement.
>
> This series adds a new log type, LOG_UNSUPP, as a way to filter the
> second case. After changing the log level of existing unsupported
> pseries hypercalls, -d unimp was reporting just the ones that I need to
> worry about and decide whether we should implement it or mark as
> unsupported in our model. After this series there's still one hypercall
> thgat is being thrown by AIX. We'll deal with that another day.

So the intention of the distinction is:
  LOG_UNIMP: we don't implement this, but we should
  LOG_UNSUPP: we don't implement this, and that's OK because it's optional

?

I think I'd be happier about adding a new log category if we had
some examples of where we should be using it other than just in
the spapr hcall code, to indicate that it's a bit more broadly
useful. If this is a distinction that only makes sense for that
narrow use case, then as Philippe says a tracepoint might be a
better choice.

thanks
-- PMM