From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Martin KaFai Lau <kafai@fb.com>
Cc: bpf@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
kernel-team@fb.com, netdev@vger.kernel.org
Subject: Re: [PATCH v2 bpf-next 03/14] bpf: Support bpf program calling kernel function
Date: Fri, 26 Mar 2021 20:59:34 -0700 [thread overview]
Message-ID: <20210327035934.7cyxbli73qqjwnqv@ast-mbp> (raw)
In-Reply-To: <20210325015142.1544736-1-kafai@fb.com>
On Wed, Mar 24, 2021 at 06:51:42PM -0700, Martin KaFai Lau wrote:
> ref_tname = btf_name_by_offset(btf, ref_t->name_off);
> - if (btf_get_prog_ctx_type(log, btf, t, env->prog->type, i)) {
> + if (btf_is_kernel(btf)) {
> + const struct btf_type *reg_ref_t;
> + const struct btf *reg_btf;
> + const char *reg_ref_tname;
> + u32 reg_ref_id;
> +
> + if (!btf_type_is_struct(ref_t)) {
> + bpf_log(log, "kernel function %s args#%d pointer type %s %s is not supported\n",
> + func_name, i, btf_type_str(ref_t),
> + ref_tname);
> + return -EINVAL;
> + }
Looks great. Applied to bpf-next.
Please follow up:
- the argument restriction of scalar and ptr_to_btf_id above should be easy to overcome.
I think either if (ptr_to_mem_ok) bit will be able to handle it
or ptr_to_btf_id can point to int/long type.
I hope some minor refactoring of these two cases will make kfunc calling more usable.
And since the code will be common would be great to add ptr_to_btf_id support
to global funcs as well. Currently ptr to struct is ptr_to_mem, so all types
inside the struct are just memory.
- please update selftest/bpf/README.rst with llvm diff url that added support for
extern funcs in BTF.
- please update bpf_design_QA.rst to make it clear that kfunc calling is not an ABI.
The kernel functions protos will change and progs will be rejected by the verifier.
Pretty much what is already in this commit log. Just copy paste into the doc, so it
doesn't get lost in git history.
next prev parent reply other threads:[~2021-03-27 4:00 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-25 1:51 [PATCH v2 bpf-next 00/14] bpf: Support calling kernel function Martin KaFai Lau
2021-03-25 1:51 ` [PATCH v2 bpf-next 01/14] bpf: Simplify freeing logic in linfo and jited_linfo Martin KaFai Lau
2021-03-25 1:51 ` [PATCH v2 bpf-next 02/14] bpf: Refactor btf_check_func_arg_match Martin KaFai Lau
2021-03-25 1:51 ` [PATCH v2 bpf-next 03/14] bpf: Support bpf program calling kernel function Martin KaFai Lau
2021-03-25 22:02 ` Toke Høiland-Jørgensen
2021-03-25 23:09 ` Martin KaFai Lau
2021-03-26 10:11 ` Toke Høiland-Jørgensen
2021-03-26 14:20 ` Alexei Starovoitov
2021-03-26 15:14 ` Toke Høiland-Jørgensen
2021-03-27 3:59 ` Alexei Starovoitov [this message]
2021-03-25 1:51 ` [PATCH v2 bpf-next 04/14] bpf: Support kernel function call in x86-32 Martin KaFai Lau
2021-03-25 1:51 ` [PATCH v2 bpf-next 05/14] tcp: Rename bictcp function prefix to cubictcp Martin KaFai Lau
2021-03-25 1:52 ` [PATCH v2 bpf-next 06/14] bpf: tcp: Put some tcp cong functions in allowlist for bpf-tcp-cc Martin KaFai Lau
2021-03-25 1:52 ` [PATCH v2 bpf-next 07/14] libbpf: Refactor bpf_object__resolve_ksyms_btf_id Martin KaFai Lau
2021-03-25 1:52 ` [PATCH v2 bpf-next 08/14] libbpf: Refactor codes for finding btf id of a kernel symbol Martin KaFai Lau
2021-03-25 1:52 ` [PATCH v2 bpf-next 09/14] libbpf: Rename RELO_EXTERN to RELO_EXTERN_VAR Martin KaFai Lau
2021-03-25 1:52 ` [PATCH v2 bpf-next 10/14] libbpf: Record extern sym relocation first Martin KaFai Lau
2021-03-25 1:52 ` [PATCH v2 bpf-next 11/14] libbpf: Support extern kernel function Martin KaFai Lau
2021-03-25 1:52 ` [PATCH v2 bpf-next 12/14] bpf: selftests: Rename bictcp to bpf_cubic Martin KaFai Lau
2021-03-25 1:52 ` [PATCH v2 bpf-next 13/14] bpf: selftests: bpf_cubic and bpf_dctcp calling kernel functions Martin KaFai Lau
2021-03-25 1:52 ` [PATCH v2 bpf-next 14/14] bpf: selftests: Add kfunc_call test Martin KaFai Lau
2021-03-27 3:50 ` [PATCH v2 bpf-next 00/14] bpf: Support calling kernel function patchwork-bot+netdevbpf
2021-03-27 21:25 ` Cong Wang
2021-03-27 21:28 ` Alexei Starovoitov
2021-03-27 22:07 ` Cong Wang
2021-03-27 22:53 ` Alexei Starovoitov
2021-03-28 20:13 ` Cong Wang
2021-03-29 1:24 ` Martin KaFai Lau
2021-03-29 16:06 ` Lorenz Bauer
2021-03-29 19:08 ` Martin KaFai Lau
2021-03-31 6:44 ` Andrii Nakryiko
2021-04-01 19:51 ` Martin KaFai Lau
2021-04-01 19:52 ` Andrii Nakryiko
2021-03-29 20:18 ` Cong Wang
2021-03-30 9:43 ` Lorenz Bauer
2021-03-30 14:35 ` Alexei Starovoitov
2021-03-30 19:58 ` Cong Wang
2021-03-30 21:43 ` Martin KaFai Lau
2021-03-31 3:28 ` [External] " Jiang Wang .
2021-03-31 4:55 ` Martin KaFai Lau
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