A side effect of supporting the SPE in guests is that we prevent the host from collecting data whilst inside a guest thus creating a black-out window. This occurs because instead of emulating the SPE, we share it with our guests.
Let's accurately describe our capabilities by using the perf exclude flags to prevent !exclude_guest and exclude_host flags from being used. Signed-off-by: Andrew Murray <[email protected]> --- drivers/perf/arm_spe_pmu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c index 2d24af4cfcab..3703dbf459de 100644 --- a/drivers/perf/arm_spe_pmu.c +++ b/drivers/perf/arm_spe_pmu.c @@ -679,6 +679,9 @@ static int arm_spe_pmu_event_init(struct perf_event *event) if (attr->exclude_idle) return -EOPNOTSUPP; + if (!attr->exclude_guest || attr->exclude_host) + return -EOPNOTSUPP; + /* * Feedback-directed frequency throttling doesn't work when we * have a buffer of samples. We'd need to manually count the -- 2.21.0 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
