Re: [kvm-unit-tests PATCH] x86: pmu: Test WRMSR on a running counter

Vitaly Kuznetsov
2020-02-05T11:45:57Z

Eric Hankland <ehankland@google.com> writes:

> Ensure that the value of the counter was successfully set to 0 after
> writing it while the counter was running.
>
> Signed-off-by: Eric Hankland <ehankland@google.com>
> ---
> x86/pmu.c | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/x86/pmu.c b/x86/pmu.c
> index cb8c9e3..8a77993 100644
> --- a/x86/pmu.c
> +++ b/x86/pmu.c
> @@ -419,6 +419,21 @@ static void check_rdpmc(void)
> report_prefix_pop();
> }
>
> +static void check_running_counter_wrmsr(void)
> +{
> + pmu_counter_t evt = {
> + .ctr = MSR_IA32_PERFCTR0,
> + .config = EVNTSEL_OS | EVNTSEL_USR | gp_events[1].unit_sel,
> + .count = 0,
> + };
> +
> + start_event(&evt);
> + loop();
> + wrmsr(MSR_IA32_PERFCTR0, 0);
> + stop_event(&evt);
> + report("running counter wrmsr", evt.count < gp_events[1].min);
> +}
> +
> int main(int ac, char **av)
> {
> struct cpuid id = cpuid(10);
> @@ -453,6 +468,7 @@ int main(int ac, char **av)
> check_counters_many();
> check_counter_overflow();
> check_gp_counter_cmask();
> + check_running_counter_wrmsr();
>
> return report_summary();
> }
>

You shall not pass [-Werror]:

gcc -mno-red-zone -mno-sse -mno-sse2 -m64 -O1 -g -MMD -MF x86/.pmu.d -fno-strict-aliasing -Wall -Wwrite-strings -Wempty-body -Wuninitialized -Wignored-qualifiers -Werror -fno-omit-frame-pointer -Wno-frame-address -fno-pic -no-pie -Wclobbered -Wunused-but-set-parameter -Wmissing-parameter-type -Wold-style-declaration -Woverride-init -Wmissing-prototypes -Wstrict-prototypes -std=gnu99 -ffreestanding -I /home/vitty/workspace/Upstream/kvm-unit-tests/lib -I /home/vitty/workspace/Upstream/kvm-unit-tests/lib/x86 -I lib -c -o x86/pmu.o x86/pmu.c
x86/pmu.c: In function ‘check_running_counter_wrmsr’:
x86/pmu.c:435:44: error: passing argument 2 of ‘report’ makes pointer from integer without a cast [-Werror=int-conversion]
435 | report("running counter wrmsr", evt.count < gp_events[1].min);
| ~~~~~~~~~~^~~~~~~~~~~~~~~~~~
| |
| int
In file included from /home/vitty/workspace/Upstream/kvm-unit-tests/lib/x86/processor.h:4,
from x86/pmu.c:3:
/home/vitty/workspace/Upstream/kvm-unit-tests/lib/libcflat.h:102:43: note: expected ‘const char *’ but argument is of type ‘int’
102 | extern void report(bool pass, const char *msg_fmt, ...)
| ~~~~~~~~~~~~^~~~~~~
cc1: all warnings being treated as errors

--
Vitaly