From: Daniel Borkmann <daniel@iogearbox.net>
To: Alexei Starovoitov <ast@kernel.org>, davem@davemloft.net
Cc: x86@kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org,
kernel-team@fb.com
Subject: Re: [PATCH v4 bpf-next 00/20] Introduce BPF trampoline
Date: Sat, 16 Nov 2019 01:01:11 +0100 [thread overview]
Message-ID: <04793b36-6a71-92cf-76f0-a4863300b35c@iogearbox.net> (raw)
In-Reply-To: <20191114185720.1641606-1-ast@kernel.org>
On 11/14/19 7:57 PM, Alexei Starovoitov wrote:
> Introduce BPF trampoline that works as a bridge between kernel functions, BPF
> programs and other BPF programs.
>
> The first use case is fentry/fexit BPF programs that are roughly equivalent to
> kprobe/kretprobe. Unlike k[ret]probe there is practically zero overhead to call
> a set of BPF programs before or after kernel function.
>
> The second use case is heavily influenced by pain points in XDP development.
> BPF trampoline allows attaching similar fentry/fexit BPF program to any
> networking BPF program. It's now possible to see packets on input and output of
> any XDP, TC, lwt, cgroup programs without disturbing them. This greatly helps
> BPF-based network troubleshooting.
>
> The third use case of BPF trampoline will be explored in the follow up patches.
> The BPF trampoline will be used to dynamicly link BPF programs. It's more
> generic mechanism than array and link list of programs used in tracing,
> networking, cgroups. In many cases it can be used as a replacement for
> bpf_tail_call-based program chaining. See [1] for long term design discussion.
>
> v3->v4:
> - Included Peter's
> "86/alternatives: Teach text_poke_bp() to emulate instructions" as a first patch.
> If it changes between now and merge window, I'll rebease to newer version.
> The patch is necessary to do s/text_poke/text_poke_bp/ in patch 3 to fix the race.
> - In patch 4 fixed bpf_trampoline creation race spotted by Andrii.
> - Added patch 15 that annotates prog->kern bpf context types. It made patches 16
> and 17 cleaner and more generic.
> - Addressed Andrii's feedback in other patches.
>
> v2->v3:
> - Addressed Song's and Andrii's comments
> - Fixed few minor bugs discovered while testing
> - Added one more libbpf patch
>
> v1->v2:
> - Addressed Andrii's comments
> - Added more test for fentry/fexit to kernel functions. Including stress test
> for maximum number of progs per trampoline.
> - Fixed a race btf_resolve_helper_id()
> - Added a patch to compare BTF types of functions arguments with actual types.
> - Added support for attaching BPF program to another BPF program via trampoline
> - Converted to use text_poke() API. That's the only viable mechanism to
> implement BPF-to-BPF attach. BPF-to-kernel attach can be refactored to use
> register_ftrace_direct() whenever it's available.
>
> [1]
> https://lore.kernel.org/bpf/20191112025112.bhzmrrh2pr76ssnh@ast-mbp.dhcp.thefacebook.com/
>
> Alexei Starovoitov (19):
> bpf: refactor x86 JIT into helpers
> bpf: Add bpf_arch_text_poke() helper
> bpf: Introduce BPF trampoline
> libbpf: Introduce btf__find_by_name_kind()
> libbpf: Add support to attach to fentry/fexit tracing progs
> selftest/bpf: Simple test for fentry/fexit
> bpf: Add kernel test functions for fentry testing
> selftests/bpf: Add test for BPF trampoline
> selftests/bpf: Add fexit tests for BPF trampoline
> selftests/bpf: Add combined fentry/fexit test
> selftests/bpf: Add stress test for maximum number of progs
> bpf: Reserve space for BPF trampoline in BPF programs
> bpf: Fix race in btf_resolve_helper_id()
> bpf: Annotate context types
> bpf: Compare BTF types of functions arguments with actual types
> bpf: Support attaching tracing BPF program to other BPF programs
> libbpf: Add support for attaching BPF programs to other BPF programs
> selftests/bpf: Extend test_pkt_access test
> selftests/bpf: Add a test for attaching BPF prog to another BPF prog
> and subprog
Applied, thanks!
prev parent reply other threads:[~2019-11-16 0:01 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-14 18:57 [PATCH v4 bpf-next 00/20] Introduce BPF trampoline Alexei Starovoitov
2019-11-14 18:57 ` [PATCH v4 bpf-next 01/20] x86/alternatives: Teach text_poke_bp() to emulate instructions Alexei Starovoitov
2019-11-14 18:57 ` [PATCH v4 bpf-next 02/20] bpf: refactor x86 JIT into helpers Alexei Starovoitov
2019-11-14 18:57 ` [PATCH v4 bpf-next 03/20] bpf: Add bpf_arch_text_poke() helper Alexei Starovoitov
2019-11-15 22:18 ` Andrii Nakryiko
2019-11-14 18:57 ` [PATCH v4 bpf-next 04/20] bpf: Introduce BPF trampoline Alexei Starovoitov
2019-11-14 18:57 ` [PATCH v4 bpf-next 05/20] libbpf: Introduce btf__find_by_name_kind() Alexei Starovoitov
2019-11-14 18:57 ` [PATCH v4 bpf-next 06/20] libbpf: Add support to attach to fentry/fexit tracing progs Alexei Starovoitov
2019-11-14 18:57 ` [PATCH v4 bpf-next 07/20] selftest/bpf: Simple test for fentry/fexit Alexei Starovoitov
2019-11-14 18:57 ` [PATCH v4 bpf-next 08/20] bpf: Add kernel test functions for fentry testing Alexei Starovoitov
2019-11-14 18:57 ` [PATCH v4 bpf-next 09/20] selftests/bpf: Add test for BPF trampoline Alexei Starovoitov
2019-11-14 18:57 ` [PATCH v4 bpf-next 10/20] selftests/bpf: Add fexit tests " Alexei Starovoitov
2019-11-14 18:57 ` [PATCH v4 bpf-next 11/20] selftests/bpf: Add combined fentry/fexit test Alexei Starovoitov
2019-11-14 18:57 ` [PATCH v4 bpf-next 12/20] selftests/bpf: Add stress test for maximum number of progs Alexei Starovoitov
2019-11-14 18:57 ` [PATCH v4 bpf-next 13/20] bpf: Reserve space for BPF trampoline in BPF programs Alexei Starovoitov
2019-11-14 18:57 ` [PATCH v4 bpf-next 14/20] bpf: Fix race in btf_resolve_helper_id() Alexei Starovoitov
2019-11-14 18:57 ` [PATCH v4 bpf-next 15/20] bpf: Annotate context types Alexei Starovoitov
2019-11-14 22:55 ` Song Liu
2019-11-14 23:01 ` Alexei Starovoitov
2019-11-14 23:19 ` Song Liu
2019-11-14 23:23 ` Song Liu
2019-11-14 18:57 ` [PATCH v4 bpf-next 16/20] bpf: Compare BTF types of functions arguments with actual types Alexei Starovoitov
2019-11-14 18:57 ` [PATCH v4 bpf-next 17/20] bpf: Support attaching tracing BPF program to other BPF programs Alexei Starovoitov
2019-11-14 23:30 ` Song Liu
2019-11-14 18:57 ` [PATCH v4 bpf-next 18/20] libbpf: Add support for attaching BPF programs " Alexei Starovoitov
2019-11-14 23:39 ` Song Liu
2019-11-14 18:57 ` [PATCH v4 bpf-next 19/20] selftests/bpf: Extend test_pkt_access test Alexei Starovoitov
2019-11-14 18:57 ` [PATCH v4 bpf-next 20/20] selftests/bpf: Add a test for attaching BPF prog to another BPF prog and subprog Alexei Starovoitov
2019-11-16 0:01 ` Daniel Borkmann [this message]
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