Re: [kvm-unit-tests PATCH 04/17] arm: gic: Support no IRQs test case

[Auger Eric <eric.auger@redhat.com>]

Hi,

On 11/12/19 2:26 PM, Alexandru Elisei wrote:
> Hi,
> 
> On 11/8/19 2:42 PM, Andre Przywara wrote:
>> For some tests it would be important to check that an IRQ was *not*
>> triggered, for instance to test certain masking operations.
>>
>> Extend the check_added() function to recognise an empty cpumask to
>> detect this situation. The timeout duration is reduced, and the "no IRQs
> 
> Why is the timeout duration reduced?
> 
>> triggered" case is actually reported as a success in this case.
>>
>> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
>> ---
>>  arm/gic.c | 10 ++++++++--
>>  1 file changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/arm/gic.c b/arm/gic.c
>> index a114009..eca9188 100644
>> --- a/arm/gic.c
>> +++ b/arm/gic.c
>> @@ -66,9 +66,10 @@ static void check_acked(const char *testname, cpumask_t *mask)
>>  	int missing = 0, extra = 0, unexpected = 0;
>>  	int nr_pass, cpu, i;
>>  	bool bad = false;
>> +	bool noirqs = cpumask_empty(mask);
>>  
>>  	/* Wait up to 5s for all interrupts to be delivered */
> 
> This comment needs updating.
> 
>> -	for (i = 0; i < 50; ++i) {
>> +	for (i = 0; i < (noirqs ? 15 : 50); ++i) {
>>  		mdelay(100);
>>  		nr_pass = 0;
>>  		for_each_present_cpu(cpu) {
>> @@ -88,7 +89,7 @@ static void check_acked(const char *testname, cpumask_t *mask)
>>  				bad = true;
>>  			}
>>  		}
>> -		if (nr_pass == nr_cpus) {
>> +		if (!noirqs && nr_pass == nr_cpus) {
> 
> This condition is pretty hard to read - what you are doing here is making sure
> that when check_acked tests that no irqs have been received, you do the entire for
> loop and wait the entire timeout duration. Did I get that right?
> 
> How about this (compile tested only):
> 
> +               if (noirqs)
> +                       /* Wait for the entire timeout duration. */
> +                       continue;
> +
>                 if (nr_pass == nr_cpus) {
>                         report("%s", !bad, testname);
>                         if (i)
> 
>>  			report("%s", !bad, testname);
>>  			if (i>>  				report_info("took more than %d ms", i * 100);
>> @@ -96,6 +97,11 @@ static void check_acked(const char *testname, cpumask_t *mask)
>>  		}
>>  	}
>>  
>> +	if (noirqs && nr_pass == nr_cpus) {
>> +		report("%s", !bad, testname);

This one looks at the result of the last iteration (on timeout).

In case of noirqs I think we should be able to return a failure as soon
as an irq is detected where we do not expect it, without waiting for the
full delay?

Thanks

Eric
> 
> bad is true only when bad_sender[cpu] != -1 or bad_irq[cpu] != -1, which only get
> set in the irq or ipi handlesr, meaning when you do get an interrupt. If nr_pass
> == nr_cpus and noirqs, then you shouldn't have gotten an interrupt. I think it's
> safe to write it as report("%s", true, testname). I think a short comment above
> explaining why we do this check (timeout expired and we haven't gotten any
> interrupts) would also improve readability of the code, but that's up to you.
> 
> Thanks,
> Alex
>> +		return;
>> +	}
>> +
>>  	for_each_present_cpu(cpu) {
>>  		if (cpumask_test_cpu(cpu, mask)) {
>>  			if (!acked[cpu])
> _______________________________________________
> kvmarm mailing list
> kvmarm@lists.cs.columbia.edu
> https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
> 


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel