Re: [PATCH kvm-unit-tests v2 2/6] s390x: smp: Test SIGP RESTART against stopped CPU

[Thomas Huth <thuth@redhat.com>]

On 11/03/2022 18.38, 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.
> 
> 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>
> Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
> Reviewed-by: Nico Boehr <nrb@linux.ibm.com>
> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
> ---
>   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);

It might be a good idea to check the return code of smp_cpu_stop() for 
success ... but that can also be done in a later patch, so for this one:

Reviewed-by: Thomas Huth <thuth@redhat.com>


>   	set_flag(0);
>   	smp_cpu_restart(1);
>   	wait_for_flag();