Re: [PATCH v9 01/10] s390x/cpus: Make absence of multithreading clear

[Pierre Morel]

On 9/5/22 13:32, Nico Boehr wrote:
> Quoting Pierre Morel (2022-09-02 09:55:22)
> > S390x do not support multithreading in the guest.
> > Do not let admin falsely specify multithreading on QEMU
> > smp commandline.
> >
> > Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> > ---
> >   hw/s390x/s390-virtio-ccw.c | 3 +++
> >   1 file changed, 3 insertions(+)
> >
> > diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
> > index 70229b102b..b5ca154e2f 100644
> > --- a/hw/s390x/s390-virtio-ccw.c
> > +++ b/hw/s390x/s390-virtio-ccw.c
> > @@ -86,6 +86,9 @@ static void s390_init_cpus(MachineState *machine)
> >       MachineClass *mc = MACHINE_GET_CLASS(machine);
> >       int i;
> >   
> > +    /* Explicitely do not support threads */
>            ^
>            Explicitly
>
> > +    assert(machine->smp.threads == 1);
>
> It might be nicer to give a better error message to the user.
> What do you think about something like (broken whitespace ahead):
>
>      if (machine->smp.threads != 1) {if (machine->smp.threads != 1) {
>          error_setg(&error_fatal, "More than one thread specified, but 
> multithreading unsupported");
>          return;
>      }


OK, I think I wanted to do this and I changed my mind, obviously, I do 
not recall why.
I will do almost the same but after a look at error.h I will use 
error_report()/exit() instead of error_setg()/return as in:


+    /* Explicitly do not support threads */
+    if (machine->smp.threads != 1) {
+        error_report("More than one thread specified, but 
multithreading unsupported");
+        exit(1);
+    }


Thanks,

Regards,
Pierre

--
Pierre Morel
IBM Lab Boeblingen