perf test: Add AMD IBS sw filter test

The kernel v6.14 added 'swfilt' to support privilege filtering in
software so that IBS can be used by regular users.  Add a test case in
x86 to verify the behavior.

  $ sudo perf test -vv 'IBS software filter'
  113: AMD IBS software filtering:
  --- start ---
  test child forked, pid 178826
  check availability of IBS swfilt
  run perf record with modifier and swfilt
  [ perf record: Woken up 3 times to write data ]
  [ perf record: Captured and wrote 0.000 MB /dev/null ]
  [ perf record: Woken up 3 times to write data ]
  [ perf record: Captured and wrote 0.000 MB /dev/null ]
  [ perf record: Woken up 3 times to write data ]
  [ perf record: Captured and wrote 0.000 MB /dev/null ]
  [ perf record: Woken up 0 times to write data ]
  [ perf record: Captured and wrote 0.000 MB /dev/null ]
  check number of samples with swfilt
  [ perf record: Woken up 3 times to write data ]
  [ perf record: Captured and wrote 0.037 MB - ]
  [ perf record: Woken up 3 times to write data ]
  [ perf record: Captured and wrote 0.041 MB - ]
  ---- end(0) ----
  113: AMD IBS software filtering                                      : Ok

Reviewed-by: Ravi Bangoria <ravi.bangoria@amd.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> # On a 9950x3d
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250524002754.1266681-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

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

@@ -0,0 +1,67 @@
+#!/bin/sh
+# AMD IBS software filtering
+
+echo "check availability of IBS swfilt"
+
+# check if IBS PMU is available
+if [ ! -d /sys/bus/event_source/devices/ibs_op ]; then
+    echo "[SKIP] IBS PMU does not exist"
+    exit 2
+fi
+
+# check if IBS PMU has swfilt format
+if [ ! -f /sys/bus/event_source/devices/ibs_op/format/swfilt ]; then
+    echo "[SKIP] IBS PMU does not have swfilt"
+    exit 2
+fi
+
+echo "run perf record with modifier and swfilt"
+
+# setting any modifiers should fail
+perf record -B -e ibs_op//u -o /dev/null true 2> /dev/null
+if [ $? -eq 0 ]; then
+    echo "[FAIL] IBS PMU should not accept exclude_kernel"
+    exit 1
+fi
+
+# setting it with swfilt should be fine
+perf record -B -e ibs_op/swfilt/u -o /dev/null true
+if [ $? -ne 0 ]; then
+    echo "[FAIL] IBS op PMU cannot handle swfilt for exclude_kernel"
+    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
+fi
+
+# check ibs_fetch PMU as well
+perf record -B -e ibs_fetch/swfilt/u -o /dev/null true
+if [ $? -ne 0 ]; then
+    echo "[FAIL] IBS fetch PMU cannot handle swfilt for exclude_kernel"
+    exit 1
+fi
+
+# check system wide recording
+perf record -aB --synth=no -e ibs_op/swfilt/k -o /dev/null true
+if [ $? -ne 0 ]; then
+    echo "[FAIL] IBS op PMU cannot handle swfilt in system-wide mode"
+    exit 1
+fi
+
+echo "check number of samples with swfilt"
+
+kernel_sample=$(perf record -e ibs_op/swfilt/u -o- true | perf script -i- -F misc | grep -c ^K)
+if [ ${kernel_sample} -ne 0 ]; then
+    echo "[FAIL] unexpected kernel samples: " ${kernel_sample}
+    exit 1
+fi
+
+user_sample=$(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
+fi