netdev - Re: [PATCH bpf-next v2 4/6] selftests/bpf: skip verifier tests for unsupported map types

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Date:   Wed, 19 Dec 2018 00:25:04 +0100
From:   Daniel Borkmann <daniel@...earbox.net>
To:     Stanislav Fomichev <sdf@...gle.com>, netdev@...r.kernel.org,
        ast@...nel.org
Cc:     davem@...emloft.net, ecree@...arflare.com,
        quentin.monnet@...ronome.com
Subject: Re: [PATCH bpf-next v2 4/6] selftests/bpf: skip verifier tests for
 unsupported map types

On 12/17/2018 07:25 PM, Stanislav Fomichev wrote:
> Use recently introduced bpf_map_type_supported() to skip tests in the
> test_verifier if map creation (create_map) fails. It's handled
> explicitly for each fixup, i.e. if bpf_create_map returns negative fd,
> we probe the kernel for the appropriate map support and skip the
> test is map type is not supported.
> 
> Signed-off-by: Stanislav Fomichev <sdf@...gle.com>
> ---
>  tools/testing/selftests/bpf/test_verifier.c | 34 +++++++++++++++++++--
>  1 file changed, 31 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
> index 124d21306c27..d267f5248b5d 100644
> --- a/tools/testing/selftests/bpf/test_verifier.c
> +++ b/tools/testing/selftests/bpf/test_verifier.c
> @@ -14221,10 +14221,20 @@ static int create_cgroup_storage(bool percpu)
>  	return fd;
>  }
>  
> +static bool skip_unsupported_map(int ret, enum bpf_map_type map_type)
> +{
> +	if (ret < 0 && !bpf_map_type_supported(map_type)) {
> +		printf("SKIP (unsupported map type %d)\n", map_type);
> +		skips++;
> +		return true;
> +	}
> +	return false;
> +}
> +
>  static char bpf_vlog[UINT_MAX >> 8];
>  
> -static void do_test_fixup(struct bpf_test *test, enum bpf_map_type prog_type,
> -			  struct bpf_insn *prog, int *map_fds)
> +static int do_test_fixup(struct bpf_test *test, enum bpf_map_type prog_type,
> +			 struct bpf_insn *prog, int *map_fds)
>  {
>  	int *fixup_map_hash_8b = test->fixup_map_hash_8b;
>  	int *fixup_map_hash_48b = test->fixup_map_hash_48b;
> @@ -14309,6 +14319,9 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_map_type prog_type,
>  
>  	if (*fixup_cgroup_storage) {
>  		map_fds[7] = create_cgroup_storage(false);
> +		if (skip_unsupported_map(map_fds[7],
> +					 BPF_MAP_TYPE_CGROUP_STORAGE))
> +			return -1;
>  		do {
>  			prog[*fixup_cgroup_storage].imm = map_fds[7];
>  			fixup_cgroup_storage++;
> @@ -14317,6 +14330,9 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_map_type prog_type,
>  
>  	if (*fixup_percpu_cgroup_storage) {
>  		map_fds[8] = create_cgroup_storage(true);
> +		if (skip_unsupported_map(map_fds[8],
> +					 BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE))
> +			return -1;
>  		do {
>  			prog[*fixup_percpu_cgroup_storage].imm = map_fds[8];
>  			fixup_percpu_cgroup_storage++;
> @@ -14325,6 +14341,8 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_map_type prog_type,
>  	if (*fixup_map_sockmap) {
>  		map_fds[9] = create_map(BPF_MAP_TYPE_SOCKMAP, sizeof(int),
>  					sizeof(int), 1);
> +		if (skip_unsupported_map(map_fds[9], BPF_MAP_TYPE_SOCKMAP))
> +			return -1;
>  		do {
>  			prog[*fixup_map_sockmap].imm = map_fds[9];
>  			fixup_map_sockmap++;
> @@ -14333,6 +14351,8 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_map_type prog_type,
>  	if (*fixup_map_sockhash) {
>  		map_fds[10] = create_map(BPF_MAP_TYPE_SOCKHASH, sizeof(int),
>  					sizeof(int), 1);
> +		if (skip_unsupported_map(map_fds[10], BPF_MAP_TYPE_SOCKHASH))
> +			return -1;
>  		do {
>  			prog[*fixup_map_sockhash].imm = map_fds[10];
>  			fixup_map_sockhash++;
> @@ -14341,6 +14361,8 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_map_type prog_type,
>  	if (*fixup_map_xskmap) {
>  		map_fds[11] = create_map(BPF_MAP_TYPE_XSKMAP, sizeof(int),
>  					sizeof(int), 1);
> +		if (skip_unsupported_map(map_fds[11], BPF_MAP_TYPE_XSKMAP))
> +			return -1;
>  		do {
>  			prog[*fixup_map_xskmap].imm = map_fds[11];
>  			fixup_map_xskmap++;
> @@ -14349,11 +14371,16 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_map_type prog_type,
>  	if (*fixup_map_stacktrace) {
>  		map_fds[12] = create_map(BPF_MAP_TYPE_STACK_TRACE, sizeof(u32),
>  					 sizeof(u64), 1);
> +		if (skip_unsupported_map(map_fds[12],
> +					 BPF_MAP_TYPE_STACK_TRACE))
> +			return -1;

Nit: Could probably be slightly simplified by moving this into and by reworking
create_{map,cgroup_storage}() a bit.

>  		do {
>  			prog[*fixup_map_stacktrace].imm = map_fds[12];
>  			fixup_map_stacktrace++;
>  		} while (fixup_map_stacktrace);
>  	}
> +
> +	return 0;
>  }
>  
>  static int set_admin(bool admin)
> @@ -14401,7 +14428,8 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
>  
>  	if (!prog_type)
>  		prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
> -	do_test_fixup(test, prog_type, prog, map_fds);
> +	if (do_test_fixup(test, prog_type, prog, map_fds) < 0)
> +		return;
>  	prog_len = probe_filter_length(prog);
>  
>  	pflags = 0;
>