Re: [PATCH bpf-next v7 2/2] selftests/bpf: Add selftests for bpf_perf_event_output

[Song Liu]

> On Jun 26, 2019, at 4:58 PM, Allan Zhang <allanzhang@xxxxxxxxxx> wrote:
> 
> From: allanzhang <allanzhang@xxxxxxxxxx>
> 
> Software event output is only enabled by a few prog types.
> This test is to ensure that all supported types are enabled for
> bpf_perf_event_output successfully.
> 
> Signed-off-by: Allan Zhang <allanzhang@xxxxxxxxxx>

Acked-by: Song Liu <songliubraving@xxxxxx>

> ---
> tools/testing/selftests/bpf/test_verifier.c   | 12 ++-
> .../selftests/bpf/verifier/event_output.c     | 94 +++++++++++++++++++
> 2 files changed, 105 insertions(+), 1 deletion(-)
> create mode 100644 tools/testing/selftests/bpf/verifier/event_output.c
> 
> diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
> index c5514daf8865..5e98d7c37eb7 100644
> --- a/tools/testing/selftests/bpf/test_verifier.c
> +++ b/tools/testing/selftests/bpf/test_verifier.c
> @@ -50,7 +50,7 @@
> #define MAX_INSNS	BPF_MAXINSNS
> #define MAX_TEST_INSNS	1000000
> #define MAX_FIXUPS	8
> -#define MAX_NR_MAPS	18
> +#define MAX_NR_MAPS	19
> #define MAX_TEST_RUNS	8
> #define POINTER_VALUE	0xcafe4all
> #define TEST_DATA_LEN	64
> @@ -84,6 +84,7 @@ struct bpf_test {
> 	int fixup_map_array_wo[MAX_FIXUPS];
> 	int fixup_map_array_small[MAX_FIXUPS];
> 	int fixup_sk_storage_map[MAX_FIXUPS];
> +	int fixup_map_event_output[MAX_FIXUPS];
> 	const char *errstr;
> 	const char *errstr_unpriv;
> 	uint32_t retval, retval_unpriv, insn_processed;
> @@ -627,6 +628,7 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type,
> 	int *fixup_map_array_wo = test->fixup_map_array_wo;
> 	int *fixup_map_array_small = test->fixup_map_array_small;
> 	int *fixup_sk_storage_map = test->fixup_sk_storage_map;
> +	int *fixup_map_event_output = test->fixup_map_event_output;
> 
> 	if (test->fill_helper) {
> 		test->fill_insns = calloc(MAX_TEST_INSNS, sizeof(struct bpf_insn));
> @@ -788,6 +790,14 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type,
> 			fixup_sk_storage_map++;
> 		} while (*fixup_sk_storage_map);
> 	}
> +	if (*fixup_map_event_output) {
> +		map_fds[18] = __create_map(BPF_MAP_TYPE_PERF_EVENT_ARRAY,
> +					   sizeof(int), sizeof(int), 1, 0);
> +		do {
> +			prog[*fixup_map_event_output].imm = map_fds[18];
> +			fixup_map_event_output++;
> +		} while (*fixup_map_event_output);
> +	}
> }
> 
> static int set_admin(bool admin)
> diff --git a/tools/testing/selftests/bpf/verifier/event_output.c b/tools/testing/selftests/bpf/verifier/event_output.c
> new file mode 100644
> index 000000000000..130553e19eca
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/verifier/event_output.c
> @@ -0,0 +1,94 @@
> +/* instructions used to output a skb based software event, produced
> + * from code snippet:
> + * struct TMP {
> + *  uint64_t tmp;
> + * } tt;
> + * tt.tmp = 5;
> + * bpf_perf_event_output(skb, &connection_tracking_event_map, 0,
> + *			 &tt, sizeof(tt));
> + * return 1;
> + *
> + * the bpf assembly from llvm is:
> + *        0:       b7 02 00 00 05 00 00 00         r2 = 5
> + *        1:       7b 2a f8 ff 00 00 00 00         *(u64 *)(r10 - 8) = r2
> + *        2:       bf a4 00 00 00 00 00 00         r4 = r10
> + *        3:       07 04 00 00 f8 ff ff ff         r4 += -8
> + *        4:       18 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00    r2 = 0ll
> + *        6:       b7 03 00 00 00 00 00 00         r3 = 0
> + *        7:       b7 05 00 00 08 00 00 00         r5 = 8
> + *        8:       85 00 00 00 19 00 00 00         call 25
> + *        9:       b7 00 00 00 01 00 00 00         r0 = 1
> + *       10:       95 00 00 00 00 00 00 00         exit
> + *
> + *     The reason I put the code here instead of fill_helpers is that map fixup
> + *     is against the insns, instead of filled prog.
> + */
> +
> +#define __PERF_EVENT_INSNS__					\
> +	BPF_MOV64_IMM(BPF_REG_2, 5),				\
> +	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -8),		\
> +	BPF_MOV64_REG(BPF_REG_4, BPF_REG_10),			\
> +	BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, -8),			\
> +	BPF_LD_MAP_FD(BPF_REG_2, 0),				\
> +	BPF_MOV64_IMM(BPF_REG_3, 0),				\
> +	BPF_MOV64_IMM(BPF_REG_5, 8),				\
> +	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,		\
> +		     BPF_FUNC_perf_event_output),		\
> +	BPF_MOV64_IMM(BPF_REG_0, 1),				\
> +	BPF_EXIT_INSN(),
> +{
> +	"perfevent for sockops",
> +	.insns = { __PERF_EVENT_INSNS__ },
> +	.prog_type = BPF_PROG_TYPE_SOCK_OPS,
> +	.fixup_map_event_output = { 4 },
> +	.result = ACCEPT,
> +	.retval = 1,
> +},
> +{
> +	"perfevent for tc",
> +	.insns =  { __PERF_EVENT_INSNS__ },
> +	.prog_type = BPF_PROG_TYPE_SCHED_CLS,
> +	.fixup_map_event_output = { 4 },
> +	.result = ACCEPT,
> +	.retval = 1,
> +},
> +{
> +	"perfevent for lwt out",
> +	.insns =  { __PERF_EVENT_INSNS__ },
> +	.prog_type = BPF_PROG_TYPE_LWT_OUT,
> +	.fixup_map_event_output = { 4 },
> +	.result = ACCEPT,
> +	.retval = 1,
> +},
> +{
> +	"perfevent for xdp",
> +	.insns =  { __PERF_EVENT_INSNS__ },
> +	.prog_type = BPF_PROG_TYPE_XDP,
> +	.fixup_map_event_output = { 4 },
> +	.result = ACCEPT,
> +	.retval = 1,
> +},
> +{
> +	"perfevent for socket filter",
> +	.insns =  { __PERF_EVENT_INSNS__ },
> +	.prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
> +	.fixup_map_event_output = { 4 },
> +	.result = ACCEPT,
> +	.retval = 1,
> +},
> +{
> +	"perfevent for sk_skb",
> +	.insns =  { __PERF_EVENT_INSNS__ },
> +	.prog_type = BPF_PROG_TYPE_SK_SKB,
> +	.fixup_map_event_output = { 4 },
> +	.result = ACCEPT,
> +	.retval = 1,
> +},
> +{
> +	"perfevent for cgroup skb",
> +	.insns =  { __PERF_EVENT_INSNS__ },
> +	.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
> +	.fixup_map_event_output = { 4 },
> +	.result = ACCEPT,
> +	.retval = 1,
> +},
> -- 
> 2.22.0.410.gd8fdbe21b5-goog
>