Re: [RFC PATCH bpf-next 14/14] selftests/bpf: Add tests for BPF static calls

[Yonghong Song <yonghong.song@linux.dev>]

On 3/18/25 7:33 AM, Anton Protopopov wrote:
> Add self-tests to test new BPF_STATIC_BRANCH_JA jump instructions
> and the BPF_STATIC_KEY_UPDATE syscall.
>
> Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
> ---
>   .../bpf/prog_tests/bpf_static_keys.c          | 359 ++++++++++++++++++
>   .../selftests/bpf/progs/bpf_static_keys.c     | 131 +++++++
>   2 files changed, 490 insertions(+)
>   create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_static_keys.c
>   create mode 100644 tools/testing/selftests/bpf/progs/bpf_static_keys.c
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_static_keys.c b/tools/testing/selftests/bpf/prog_tests/bpf_static_keys.c
> new file mode 100644
> index 000000000000..3f105d36743b
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/bpf_static_keys.c
> @@ -0,0 +1,359 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <test_progs.h>
> +
> +#include <sys/syscall.h>
> +#include <bpf/bpf.h>
> +
> +#include "bpf_static_keys.skel.h"
> +
> +#define VAL_ON	7
> +#define VAL_OFF	3
> +
> +enum {
> +	OFF,
> +	ON
> +};
> +
> +static int _bpf_prog_load(struct bpf_insn *insns, __u32 insn_cnt)
> +{
> +	return bpf_prog_load(BPF_PROG_TYPE_XDP, NULL, "GPL", insns, insn_cnt, NULL);
> +}
> +
> +static int _bpf_static_key_update(int map_fd, __u32 on)
> +{
> +	LIBBPF_OPTS(bpf_static_key_update_opts, opts);
> +
> +	opts.on = on;
> +
> +	return bpf_static_key_update(map_fd, &opts);
> +}
> +
> +#define BPF_JMP32_OR_NOP(IMM, OFF)				\
> +	((struct bpf_insn) {					\
> +		.code  = BPF_JMP32 | BPF_JA | BPF_K,		\
> +		.dst_reg = 0,					\
> +		.src_reg = BPF_STATIC_BRANCH_JA,		\
> +		.off   = OFF,					\
> +		.imm   = IMM })
> +
> +#define BPF_JMP_OR_NOP(IMM, OFF)				\
> +	((struct bpf_insn) {					\
> +		.code  = BPF_JMP | BPF_JA | BPF_K,		\
> +		.dst_reg = 0,					\
> +		.src_reg = BPF_STATIC_BRANCH_JA,		\
> +		.off   = OFF,					\
> +		.imm   = IMM })
> +
> +#define BPF_NOP_OR_JMP32(IMM, OFF)				\
> +	((struct bpf_insn) {					\
> +		.code  = BPF_JMP32 | BPF_JA | BPF_K,		\
> +		.dst_reg = 0,					\
> +		.src_reg = BPF_STATIC_BRANCH_JA |		\
> +			   BPF_STATIC_BRANCH_NOP,		\
> +		.off   = OFF,					\
> +		.imm   = IMM })
> +
> +#define BPF_NOP_OR_JMP(IMM, OFF)				\
> +	((struct bpf_insn) {					\
> +		.code  = BPF_JMP | BPF_JA | BPF_K,		\
> +		.dst_reg = 0,					\
> +		.src_reg = BPF_STATIC_BRANCH_JA |		\
> +			   BPF_STATIC_BRANCH_NOP,		\
> +		.off   = OFF,					\
> +		.imm   = IMM })
> +
> +static const struct bpf_insn insns0[] = {
> +	BPF_JMP_OR_NOP(0, 1),
> +	BPF_NOP_OR_JMP(0, 1),
> +	BPF_JMP32_OR_NOP(1, 0),
> +	BPF_NOP_OR_JMP32(1, 0),
> +};
> +

[...]

> +
> +static void check_bpf_to_bpf_call(struct bpf_static_keys *skel,
> +				  struct bpf_map *key1,
> +				  struct bpf_map *key2)
> +{
> +	struct bpf_link *link;
> +
> +	link = bpf_program__attach(skel->progs.check_bpf_to_bpf_call);

there is no progcheck_bpf_to_bpf_call. Compilation will fail.

> +	if (!ASSERT_OK_PTR(link, "link"))
> +		return;
> +
> +	__check_multiple_keys(skel, key1, key2, 0, 303, 3030, 3333);
> +
> +	bpf_link__destroy(link);
> +}
> +
[...]