perf test: AMD IBS swfilt skip kernel tests if paranoia is >1

If not root and the perf_event_paranoid is set >1 swfilt will fail to
open the event failing the test. Add check to skip the test in that
case.

Fixes: 0e71bcdcf1 ("perf test: Add AMD IBS sw filter test")
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Collin Funk <collin.funk1@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Link: https://lore.kernel.org/r/20250913000350.1306948-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/shell/amd-ibs-swfilt.sh

@@ -1,6 +1,10 @@
 #!/bin/bash
 # AMD IBS software filtering
 
+ParanoidAndNotRoot() {
+  [ "$(id -u)" != 0 ] && [ "$(cat /proc/sys/kernel/perf_event_paranoid)" -gt $1 ]
+}
+
 echo "check availability of IBS swfilt"
 
 # check if IBS PMU is available
@@ -16,6 +20,7 @@ if [ ! -f /sys/bus/event_source/devices/ibs_op/format/swfilt ]; then
 fi
 
 echo "run perf record with modifier and swfilt"
+err=0
 
 # setting any modifiers should fail
 perf record -B -e ibs_op//u -o /dev/null true 2> /dev/null
@@ -31,11 +36,17 @@ if [ $? -ne 0 ]; then
     exit 1
 fi
 
-# setting it with swfilt=1 should be fine
-perf record -B -e ibs_op/swfilt=1/k -o /dev/null true
-if [ $? -ne 0 ]; then
-    echo "[FAIL] IBS op PMU cannot handle swfilt for exclude_user"
-    exit 1
+if ! ParanoidAndNotRoot 1
+then
+    # setting it with swfilt=1 should be fine
+    perf record -B -e ibs_op/swfilt=1/k -o /dev/null true
+    if [ $? -ne 0 ]; then
+        echo "[FAIL] IBS op PMU cannot handle swfilt for exclude_user"
+        exit 1
+    fi
+else
+    echo "[SKIP] not root and perf_event_paranoid too high for exclude_user"
+    err=2
 fi
 
 # check ibs_fetch PMU as well
@@ -46,10 +57,16 @@ if [ $? -ne 0 ]; then
 fi
 
 # check system wide recording
-perf record -aB --synth=no -e ibs_op/swfilt/k -o /dev/null true
-if [ $? -ne 0 ]; then
-    echo "[FAIL] IBS op PMU cannot handle swfilt in system-wide mode"
-    exit 1
+if ! ParanoidAndNotRoot 0
+then
+    perf record -aB --synth=no -e ibs_op/swfilt/k -o /dev/null true
+    if [ $? -ne 0 ]; then
+        echo "[FAIL] IBS op PMU cannot handle swfilt in system-wide mode"
+        exit 1
+    fi
+else
+    echo "[SKIP] not root and perf_event_paranoid too high for system-wide/exclude_user"
+    err=2
 fi
 
 echo "check number of samples with swfilt"
@@ -60,8 +77,16 @@ if [ ${kernel_sample} -ne 0 ]; then
     exit 1
 fi
 
-user_sample=$(perf record -e ibs_fetch/swfilt/k -o- true | perf script -i- -F misc | grep -c ^U)
-if [ ${user_sample} -ne 0 ]; then
-    echo "[FAIL] unexpected user samples: " ${user_sample}
-    exit 1
+if ! ParanoidAndNotRoot 1
+then
+    user_sample=$(perf record -e ibs_fetch/swfilt/k -o- true | perf script -i- -F misc | grep -c ^U)
+    if [ ${user_sample} -ne 0 ]; then
+        echo "[FAIL] unexpected user samples: " ${user_sample}
+        exit 1
+    fi
+else
+    echo "[SKIP] not root and perf_event_paranoid too high for exclude_user"
+    err=2
 fi
+
+exit $err