The following commit has been merged into the perf/core branch of tip:
Commit-ID: 7c2128235eff99b448af8f4b5b2933495bf1a440
Gitweb: https://git.kernel.org/tip/7c2128235eff99b448af8f4b5b2933495bf1a440
Author: Ravi Bangoria <ravi.bangoria@xxxxxxx>
AuthorDate: Tue, 20 Jun 2023 14:46:03 +05:30
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Mon, 10 Jul 2023 09:52:34 +02:00
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@xxxxxxx>
Signed-off-by: Ravi Bangoria <ravi.bangoria@xxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20230620091603.269-1-ravi.bangoria@xxxxxxx
---
arch/x86/events/amd/ibs.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
index 3710148..74e6642 100644
--- a/arch/x86/events/amd/ibs.c
+++ b/arch/x86/events/amd/ibs.c
@@ -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 */
|