Messages in this thread Patch in this message | | | Date | Fri, 21 Feb 2020 14:41:33 -0800 | Subject | [kvm-unit-tests PATCH] x86: pmu: Test perfctr overflow after WRMSR on a running counter | From | Eric Hankland <> |
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Ensure that a WRMSR on a running counter will correctly update when the counter should overflow (similar to the existing overflow test case but with the counter being written to while it is running).
Signed-off-by: Eric Hankland <ehankland@google.com> --- x86/pmu.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/x86/pmu.c b/x86/pmu.c index c8096b8..f45621a 100644 --- a/x86/pmu.c +++ b/x86/pmu.c @@ -422,17 +422,34 @@ static void check_rdpmc(void) static void check_running_counter_wrmsr(void) { + uint64_t status; pmu_counter_t evt = { .ctr = MSR_IA32_PERFCTR0, .config = EVNTSEL_OS | EVNTSEL_USR | gp_events[1].unit_sel, .count = 0, }; + report_prefix_push("running counter wrmsr"); + start_event(&evt); loop(); wrmsr(MSR_IA32_PERFCTR0, 0); stop_event(&evt); - report(evt.count < gp_events[1].min, "running counter wrmsr"); + report(evt.count < gp_events[1].min, "cntr"); + + /* clear status before overflow test */ + wrmsr(MSR_CORE_PERF_GLOBAL_OVF_CTRL, + rdmsr(MSR_CORE_PERF_GLOBAL_STATUS)); + + evt.count = 0; + start_event(&evt); + wrmsr(MSR_IA32_PERFCTR0, -1); + loop(); + stop_event(&evt); + status = rdmsr(MSR_CORE_PERF_GLOBAL_STATUS); + report(status & 1, "status"); + + report_prefix_pop(); } int main(int ac, char **av)
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