Re: [PATCH 83/84] exec/poison: Do not poison CONFIG_SOFTMMU

[Richard Henderson]

On 5/8/23 16:19, Thomas Huth wrote:
> On 08/05/2023 17.14, Paolo Bonzini wrote:
> > On 5/8/23 16:27, Thomas Huth wrote:
> > > On 03/05/2023 09.23, Richard Henderson wrote:
> > > > If CONFIG_USER_ONLY is ok generically, so is CONFIG_SOFTMMU,
> > > > because they are exactly opposite.
> > >
> > > I thought there was a difference ... at least in the past?
> > > But looking at meson.build they seem to be handled quite equally now:
> > >
> > > common_ss.add_all(when: 'CONFIG_SOFTMMU', if_true: [softmmu_ss])
> > > common_ss.add_all(when: 'CONFIG_USER_ONLY', if_true: user_ss)
> > >
> > > Paolo, do you remember whether there was a difference in the past?
> >
> > No, I don't think so.  Really _none_ of them are okay in general, but now that we have 
> > softmmu_ss/user_ss there is a usecase for using them in "generic" sourcesets.  So 
> > perhaps we could have something like
> >
> > /* One of these is always defined in files that can use them.  */
> > #if !defined CONFIG_SOFTMMU && !defined CONFIG_USER_ONLY
> > #pragma GCC poison CONFIG_SOFTMMU
> > #pragma GCC poison CONFIG_USER_ONLY
> > #endif
>
> That's the thing that I had in mind:
>
> https://lists.gnu.org/archive/html/qemu-devel/2021-03/msg05269.html
>
> ... so instead of removing the poison from CONFIG_SOFTMMU, we should likely rather try to 
> get CONFIG_USER_ONLY poisoned, too.

A worthy goal, but a large job, just looking at "exec/cpu-common.h".

I will defer that to another patch set, and continue with non-poisoning of CONFIG_SOFTMMU 
for now.


r~