Commit 7c212823 authored by Ravi Bangoria's avatar Ravi Bangoria Committed by Peter Zijlstra
Browse files

perf/amd: Prevent grouping of IBS events 



IBS PMUs can have only one event active at any point in time. Restrict
grouping of multiple IBS events.

Reported-by: default avatarSandipan Das <sandipan.das@amd.com>
Signed-off-by: default avatarRavi Bangoria <ravi.bangoria@amd.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230620091603.269-1-ravi.bangoria@amd.com
parent 06c2afb8

arch/x86/events/amd/ibs.c

+26 −0
Original line number Diff line number Diff line
@@ -247,11 +247,33 @@ int forward_event_to_ibs(struct perf_event *event) 
	return -ENOENT;

}



/*

 * Grouping of IBS events is not possible since IBS can have only

 * one event active at any point in time.

 */

static int validate_group(struct perf_event *event)

{

	struct perf_event *sibling;



	if (event->group_leader == event)

		return 0;



	if (event->group_leader->pmu == event->pmu)

		return -EINVAL;



	for_each_sibling_event(sibling, event->group_leader) {

		if (sibling->pmu == event->pmu)

			return -EINVAL;

	}

	return 0;

}



static int perf_ibs_init(struct perf_event *event)

{

	struct hw_perf_event *hwc = &event->hw;

	struct perf_ibs *perf_ibs;

	u64 max_cnt, config;

	int ret;



	perf_ibs = get_ibs_pmu(event->attr.type);

	if (!perf_ibs)
@@ -265,6 +287,10 @@ static int perf_ibs_init(struct perf_event *event) 
	if (config & ~perf_ibs->config_mask)

		return -EINVAL;



	ret = validate_group(event);

	if (ret)

		return ret;



	if (hwc->sample_period) {

		if (config & perf_ibs->cnt_mask)

			/* raw max_cnt may not be set */