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

[Nico Boehr <nrb@xxxxxxxxxxxxx>]

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@xxxxxxxxxxxxx>
> ---
>  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) {
        error_setg(&error_fatal, "More than one thread specified, but multithreading unsupported");
        return;
    }