VMs running on latest kernel support LBR. However, bpf_get_branch_snapshot
couldn't stop the LBR before too many entries are flushed. Skip the test
for VMs before we find a proper fix for VMs.
Read the "flags" line from /proc/cpuinfo, if it contains "hypervisor",
skip test get_branch_snapshot.
Fixes: 025bd7c753aa (selftests/bpf: Add test for bpf_get_branch_snapshot)
Signed-off-by: Song Liu <songliubraving@xxxxxx>
---
.../bpf/prog_tests/get_branch_snapshot.c | 32 +++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/get_branch_snapshot.c b/tools/testing/selftests/bpf/prog_tests/get_branch_snapshot.c
index 67e86f8d86775..bf9d47a859449 100644
--- a/tools/testing/selftests/bpf/prog_tests/get_branch_snapshot.c
+++ b/tools/testing/selftests/bpf/prog_tests/get_branch_snapshot.c
@@ -6,6 +6,30 @@
static int *pfd_array;
static int cpu_cnt;
+static bool is_hypervisor(void)
+{
+ char *line = NULL;
+ bool ret = false;
+ size_t len;
+ FILE *fp;
+
+ fp = fopen("/proc/cpuinfo", "r");
+ if (!fp)
+ return false;
+
+ while (getline(&line, &len, fp) != -1) {
+ if (strstr(line, "flags") == line) {
+ if (strstr(line, "hypervisor") != NULL)
+ ret = true;
+ break;
+ }
+ }
+
+ free(line);
+ fclose(fp);
+ return ret;
+}
+
static int create_perf_events(void)
{
struct perf_event_attr attr = {0};
@@ -54,6 +78,14 @@ void test_get_branch_snapshot(void)
struct get_branch_snapshot *skel = NULL;
int err;
+ if (is_hypervisor()) {
+ /* As of today, LBR in hypervisor cannot be stopped before
+ * too many entries are flushed. Skip the test for now in
+ * hypervisor until we optimize the LBR in hypervisor.
+ */
+ test__skip();
+ return;
+ }
if (create_perf_events()) {
test__skip(); /* system doesn't support LBR */
goto cleanup;
--
2.30.2
