Re: [PATCH kvm-unit-tests v1 2/6] s390x: smp: Test SIGP RESTART against stopped CPU

[Eric Farman <farman@linux.ibm.com>]

On Fri, 2022-03-04 at 11:43 +0100, Janosch Frank wrote:
> On 3/3/22 22:04, Eric Farman wrote:
> > test_restart() makes two smp_cpu_restart() calls against CPU 1.
> > It claims to perform both of them against running (operating) CPUs,
> > but the first invocation tries to achieve this by calling
> > smp_cpu_stop() to CPU 0. This will be rejected by the library.
> 
> I played myself there :)

:)

> 
> > Let's fix this by making the first restart operate on a stopped
> > CPU,
> > to ensure it gets test coverage instead of relying on other
> > callers.
> > 
> > Fixes: 166da884d ("s390x: smp: Add restart when running test")
> > Signed-off-by: Eric Farman <farman@linux.ibm.com>
> 
> If you want to you can add a report_pass() after the first wait flag.

I did in patch 5. I can move that here, but that patch has some
additional prefix changes for those reports, so didn't want to move TOO
much of that to this fix.

> 
> Reviewed-by: Janosch Frank <frankja@linux.ibm.com>

Thank you!

> 
> > ---
> >   s390x/smp.c | 8 ++------
> >   1 file changed, 2 insertions(+), 6 deletions(-)
> > 
> > diff --git a/s390x/smp.c b/s390x/smp.c
> > index 068ac74d..2f4af820 100644
> > --- a/s390x/smp.c
> > +++ b/s390x/smp.c
> > @@ -50,10 +50,6 @@ static void test_start(void)
> >   	report_pass("start");
> >   }
> >   
> > -/*
> > - * Does only test restart when the target is running.
> > - * The other tests do restarts when stopped multiple times
> > already.
> > - */
> >   static void test_restart(void)
> >   {
> >   	struct cpu *cpu = smp_cpu_from_idx(1);
> > @@ -62,8 +58,8 @@ static void test_restart(void)
> >   	lc->restart_new_psw.mask = extract_psw_mask();
> >   	lc->restart_new_psw.addr = (unsigned long)test_func;
> >   
> > -	/* Make sure cpu is running */
> > -	smp_cpu_stop(0);
> > +	/* Make sure cpu is stopped */
> > +	smp_cpu_stop(1);
> >   	set_flag(0);
> >   	smp_cpu_restart(1);
> >   	wait_for_flag();