Re: [PATCH v11 net-next 12/12] bpf: mini eBPF library, test stubs and verifier testsuite

From: Daniel Borkmann
Date: Wed Sep 10 2014 - 07:35:57 EST


On 09/10/2014 07:10 AM, Alexei Starovoitov wrote:
1.
the library includes a trivial set of BPF syscall wrappers:
int bpf_create_map(int key_size, int value_size, int max_entries);
int bpf_update_elem(int fd, void *key, void *value);
int bpf_lookup_elem(int fd, void *key, void *value);
int bpf_delete_elem(int fd, void *key);
int bpf_get_next_key(int fd, void *key, void *next_key);
int bpf_prog_load(enum bpf_prog_type prog_type,
const struct sock_filter_int *insns, int insn_len,
const char *license);
bpf_prog_load() stores verifier log into global bpf_log_buf[] array

2.
test stubs configure eBPF infra with 'unspec' map and program types.
These are fake types used by user space testsuite only.

3.
verifier tests valid and invalid programs and expects predefined
error log messages from kernel.
40 tests so far.

$ sudo ./test_verifier
#0 add+sub+mul OK
#1 unreachable OK
#2 unreachable2 OK
#3 out of range jump OK
#4 out of range jump2 OK
#5 test1 ld_imm64 OK
...

Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxxxx>

Since we already have an extensive BPF test suite, that is, lib/test_bpf.c,
which currently also does sanity checks for the classic BPF verifier, is
there a reason these verifier test cases cannot be extended/integrated there
as well but have to go to kernel/bpf/test_stub.c resp. samples/bpf/test_verifier.c ?
I don't like that we put testing code into kernel/bpf/ whereas we already
have a BPF test infrastructure in the kernel elsewhere.
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