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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: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230620091603.269-1-ravi.bangoria@amd.com
This commit is contained in:
Ravi Bangoria 2023-06-20 14:46:03 +05:30 committed by Peter Zijlstra
parent 06c2afb862
commit 7c2128235e
1 changed files with 26 additions and 0 deletions
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26
arch/x86/events/amd/ibs.c
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@ -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 */