perf test: Update event group check for support of uncore event

The event group test checks group creation for combinations of hw, sw
and uncore PMU events. Some of the uncore pmus may require additional
permission to access the counters.

For example, in case of hv_24x7, partition need to have permissions to
access hv_24x7 pmu counters. If not, event_open will fail. Hence add a
sanity check to see if event_open succeeds before proceeding with the
test.

Fixes: 9d9b22bedad13d96 ("perf test: Add event group test for events in multiple PMUs")
Signed-off-by: Athira Jajeev <[e-mail]>
Acked-by: Ravi Bangoria <[e-mail]>
Cc: Disha Goel <[e-mail]>
Cc: Ian Rogers <[e-mail]>
Cc: James Clark <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Kajol Jain <[e-mail]>
Cc: [e-mail]
Cc: Madhavan Srinivasan <[e-mail]>
Cc: Michael Ellerman <[e-mail]>
Cc: Nageswara R Sastry <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Ravi Bangoria <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/tests/event_groups.c

···
 static int setup_uncore_event(void)
 {
 	struct perf_pmu *pmu;
-	int i;
+	int i, fd;
 
 	if (list_empty(&pmus))
 		perf_pmu__scan(NULL);
···
 				pr_debug("Using %s for uncore pmu event\n", pmu->name);
 				types[2] = pmu->type;
 				configs[2] = uncore_pmus[i].config;
+				/*
+				 * Check if the chosen uncore pmu event can be
+				 * used in the test. For example, incase of accessing
+				 * hv_24x7 pmu counters, partition should have
+				 * additional permissions. If not, event open will
+				 * fail. So check if the event open succeeds
+				 * before proceeding.
+				 */
+				fd = event_open(types[2], configs[2], -1);
+				if (fd < 0)
+					return -1;
+				close(fd);
 				return 0;
 			}
 		}