From aa67fdb4643616f04cb59b6d090010c371ab1a80 Mon Sep 17 00:00:00 2001 From: Song Liu Date: Wed, 6 Oct 2021 22:02:31 -0700 Subject: [PATCH] selftests/bpf: Skip the second half of get_branch_snapshot in vm VMs running on upstream 5.12+ kernel support LBR. However, bpf_get_branch_snapshot couldn't stop the LBR before too many entries are flushed. Skip the hit/waste test for VMs before we find a proper fix for LBR in VM. Fixes: 025bd7c753aa ("selftests/bpf: Add test for bpf_get_branch_snapshot") Signed-off-by: Song Liu Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20211007050231.728496-1-songliubraving@fb.com --- .../selftests/bpf/prog_tests/get_branch_snapshot.c | 34 ++++++++++++++++++++++ 1 file changed, 34 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 67e86f8d8677..e4f92feb7b32 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 (!strncmp(line, "flags", 5)) { + 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}; @@ -83,6 +107,16 @@ void test_get_branch_snapshot(void) goto cleanup; } + if (is_hypervisor()) { + /* As of today, LBR in hypervisor cannot be stopped before + * too many entries are flushed. Skip the hit/waste test + * for now in hypervisor until we optimize the LBR in + * hypervisor. + */ + test__skip(); + goto cleanup; + } + ASSERT_GT(skel->bss->test1_hits, 6, "find_looptest_in_lbr"); /* Given we stop LBR in software, we will waste a few entries. -- 2.11.0