From: Lorenz Bauer <lmb@cloudflare.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: "David S . Miller" <davem@davemloft.net>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
mcroce@microsoft.com, bpf <bpf@vger.kernel.org>,
Kernel Team <kernel-team@fb.com>
Subject: Re: [PATCH RFC bpf-next 00/10] bpf: CO-RE support in the kernel.
Date: Mon, 27 Sep 2021 17:12:15 +0100 [thread overview]
Message-ID: <CACAyw99aR5sfGZ5OQuRrz6Rt+sOkm6B2vC=JfK1tPqdf6961tw@mail.gmail.com> (raw)
In-Reply-To: <20210924231313.jbg4cs3wk63ii54a@ast-mbp.lan>
On Sat, 25 Sept 2021 at 00:13, Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> On Thu, Sep 23, 2021 at 12:33:58PM +0100, Lorenz Bauer wrote:
> >
> > Some questions:
> > * How can this handle kernels that don't have built-in BTF? Not a
> > problem for myself, but some people have to deal with BTF-less distro
> > kernels by using pahole to generate external BTF from debug symbols.
> > Can we accommodate that?
>
> I think so, but it probably should be done as a generic feature:
> "populate kernel BTF".
> When kernel wasn't compiled with BTF there could be a way to
> populate it with such. Just like we do sys_bpf(BTF_LOAD)
> for program's BTF we can allow populating vmlinux BTF this way.
> Unlike builtin BTF it wouldn't be trusted for certain verifier assumptions,
> but better than nothing and more convenient than specifying BTF file
> on a side for every bpf prog load with traditional libbpf style.
From my POV we already have an API for external BTF (and I think
libbpf does too?) but would need a new API for "load kernel BTF".
Global state like this also doesn't work well for several individual
processes. Imagine multiple programs on the system trying to each
replace the kernel BTF, how would that work? Which one wins? Being
able to give my own fd for kernel BTF circumvents all those problems
and seems much cleaner to me.
Lorenz
--
Lorenz Bauer | Systems Engineer
6th Floor, County Hall/The Riverside Building, SE1 7PB, UK
www.cloudflare.com
next prev parent reply other threads:[~2021-09-27 16:12 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-17 21:57 [PATCH RFC bpf-next 00/10] bpf: CO-RE support in the kernel Alexei Starovoitov
2021-09-17 21:57 ` [PATCH RFC bpf-next 01/10] bpf: Prepare relo_core.c for kernel duty Alexei Starovoitov
2021-09-21 21:25 ` Andrii Nakryiko
2021-09-28 14:45 ` Matteo Croce
2021-09-28 16:37 ` Alexei Starovoitov
2021-09-28 17:11 ` Matteo Croce
2021-09-28 20:34 ` Alexei Starovoitov
2021-09-29 12:32 ` Matteo Croce
2021-09-29 17:38 ` Matteo Croce
2021-09-29 23:00 ` Alexei Starovoitov
2021-09-29 23:49 ` Matteo Croce
2021-10-22 0:48 ` Matteo Croce
2021-10-22 0:51 ` Alexei Starovoitov
2021-09-17 21:57 ` [PATCH RFC bpf-next 02/10] bpf: Define enum bpf_core_relo_kind as uapi Alexei Starovoitov
2021-09-21 21:27 ` Andrii Nakryiko
2021-09-17 21:57 ` [PATCH RFC bpf-next 03/10] bpf: Add proto of bpf_core_apply_relo() Alexei Starovoitov
2021-09-23 11:21 ` Lorenz Bauer
2021-09-23 18:48 ` Andrii Nakryiko
2021-09-17 21:57 ` [PATCH RFC bpf-next 04/10] bpf: Add bpf_core_add_cands() and wire it into bpf_core_apply_relo_insn() Alexei Starovoitov
2021-09-21 21:34 ` Andrii Nakryiko
2021-09-27 18:04 ` Matteo Croce
2021-09-17 21:57 ` [PATCH RFC bpf-next 05/10] libbpf: Use CO-RE in the kernel in light skeleton Alexei Starovoitov
2021-09-17 21:57 ` [PATCH RFC bpf-next 06/10] libbpf: Make gen_loader data aligned Alexei Starovoitov
2021-09-17 21:57 ` [PATCH RFC bpf-next 07/10] libbpf: Support init of inner maps in light skeleton Alexei Starovoitov
2021-09-17 21:57 ` [PATCH RFC bpf-next 08/10] selftests/bpf: Convert kfunc test with CO-RE to lskel Alexei Starovoitov
2021-09-17 21:57 ` [PATCH RFC bpf-next 09/10] selftests/bpf: Improve inner_map test coverage Alexei Starovoitov
2021-09-17 21:57 ` [PATCH RFC bpf-next 10/10] selftests/bpf: Convert map_ptr_kern test to use light skeleton Alexei Starovoitov
2021-09-23 11:33 ` [PATCH RFC bpf-next 00/10] bpf: CO-RE support in the kernel Lorenz Bauer
2021-09-23 18:52 ` Andrii Nakryiko
2021-09-24 23:13 ` Alexei Starovoitov
2021-09-27 16:12 ` Lorenz Bauer [this message]
2021-09-27 16:50 ` Alexei Starovoitov
2021-09-28 8:30 ` Lorenz Bauer
2021-09-28 16:35 ` Alexei Starovoitov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CACAyw99aR5sfGZ5OQuRrz6Rt+sOkm6B2vC=JfK1tPqdf6961tw@mail.gmail.com' \
--to=lmb@cloudflare.com \
--cc=alexei.starovoitov@gmail.com \
--cc=andrii@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=davem@davemloft.net \
--cc=john.fastabend@gmail.com \
--cc=kernel-team@fb.com \
--cc=mcroce@microsoft.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).