From: Lorenz Bauer <lmb@cloudflare.com>
To: Jakub Kicinski <kuba@kernel.org>
Cc: "Lorenzo Bianconi" <lorenzo@kernel.org>,
bpf <bpf@vger.kernel.org>, Networking <netdev@vger.kernel.org>,
"Lorenzo Bianconi" <lorenzo.bianconi@redhat.com>,
"David S . Miller" <davem@davemloft.net>,
"Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
shayagr@amazon.com, "John Fastabend" <john.fastabend@gmail.com>,
"David Ahern" <dsahern@kernel.org>,
"Jesper Dangaard Brouer" <brouer@redhat.com>,
"Eelco Chaudron" <echaudro@redhat.com>,
"Jason Wang" <jasowang@redhat.com>,
"Alexander Duyck" <alexander.duyck@gmail.com>,
"Saeed Mahameed" <saeed@kernel.org>,
"Maciej Fijalkowski" <maciej.fijalkowski@intel.com>,
"Karlsson, Magnus" <magnus.karlsson@intel.com>,
tirthendu.sarkar@intel.com,
"Toke Høiland-Jørgensen" <toke@redhat.com>
Subject: Re: [PATCH v14 bpf-next 00/18] mvneta: introduce XDP multi-buffer support
Date: Wed, 29 Sep 2021 11:41:53 +0100 [thread overview]
Message-ID: <CACAyw9-8t8RpJgJUTd7u6bOLnJ1xQsgK7z37QrL9T1FUaJ7WNQ@mail.gmail.com> (raw)
In-Reply-To: <20210916095539.4696ae27@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
On Thu, 16 Sept 2021 at 18:47, Jakub Kicinski <kuba@kernel.org> wrote:
>
> Won't applications end up building something like skb_header_pointer()
> based on bpf_xdp_adjust_data(), anyway? In which case why don't we
> provide them what they need?
>
> say:
>
> void *xdp_mb_pointer(struct xdp_buff *xdp_md, u32 flags,
> u32 offset, u32 len, void *stack_buf)
>
> flags and offset can be squashed into one u64 as needed. Helper returns
> pointer to packet data, either real one or stack_buf. Verifier has to
> be taught that the return value is NULL or a pointer which is safe with
> offsets up to @len.
>
> If the reason for access is write we'd also need:
>
> void *xdp_mb_pointer_flush(struct xdp_buff *xdp_md, u32 flags,
> u32 offset, u32 len, void *stack_buf)
Yes! This would be so much better than bpf_skb_load/store_bytes(),
especially if we can use it for both XDP and skb contexts as stated
elsewhere in this thread.
--
Lorenz Bauer | Systems Engineer
6th Floor, County Hall/The Riverside Building, SE1 7PB, UK
www.cloudflare.com
next prev parent reply other threads:[~2021-09-29 10:42 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-10 16:14 [PATCH v14 bpf-next 00/18] mvneta: introduce XDP multi-buffer support Lorenzo Bianconi
2021-09-10 16:14 ` [PATCH v14 bpf-next 01/18] net: skbuff: add size metadata to skb_shared_info for xdp Lorenzo Bianconi
2021-09-10 16:18 ` Jesper Dangaard Brouer
2021-09-10 16:14 ` [PATCH v14 bpf-next 02/18] xdp: introduce flags field in xdp_buff/xdp_frame Lorenzo Bianconi
2021-09-10 16:19 ` Jesper Dangaard Brouer
2021-09-10 16:14 ` [PATCH v14 bpf-next 03/18] net: mvneta: update mb bit before passing the xdp buffer to eBPF layer Lorenzo Bianconi
2021-09-20 8:25 ` Shay Agroskin
2021-09-20 8:37 ` Lorenzo Bianconi
2021-09-20 8:45 ` Shay Agroskin
2021-09-20 9:00 ` Lorenzo Bianconi
2021-09-10 16:14 ` [PATCH v14 bpf-next 04/18] net: mvneta: simplify mvneta_swbm_add_rx_fragment management Lorenzo Bianconi
2021-09-10 16:14 ` [PATCH v14 bpf-next 05/18] net: xdp: add xdp_update_skb_shared_info utility routine Lorenzo Bianconi
2021-09-10 16:14 ` [PATCH v14 bpf-next 06/18] net: marvell: rely on " Lorenzo Bianconi
2021-09-10 16:14 ` [PATCH v14 bpf-next 07/18] xdp: add multi-buff support to xdp_return_{buff/frame} Lorenzo Bianconi
2021-09-10 16:14 ` [PATCH v14 bpf-next 08/18] net: mvneta: add multi buffer support to XDP_TX Lorenzo Bianconi
2021-09-10 16:14 ` [PATCH v14 bpf-next 09/18] net: mvneta: enable jumbo frames for XDP Lorenzo Bianconi
2021-09-10 16:14 ` [PATCH v14 bpf-next 10/18] bpf: add multi-buff support to the bpf_xdp_adjust_tail() API Lorenzo Bianconi
2021-09-16 16:55 ` Jakub Kicinski
2021-09-17 10:02 ` Lorenzo Bianconi
2021-09-17 13:03 ` Jakub Kicinski
2021-09-10 16:14 ` [PATCH v14 bpf-next 11/18] bpf: introduce bpf_xdp_get_buff_len helper Lorenzo Bianconi
2021-09-10 16:14 ` [PATCH v14 bpf-next 12/18] bpf: add multi-buffer support to xdp copy helpers Lorenzo Bianconi
2021-09-10 16:14 ` [PATCH v14 bpf-next 13/18] bpf: move user_size out of bpf_test_init Lorenzo Bianconi
2021-09-10 16:14 ` [PATCH v14 bpf-next 14/18] bpf: introduce multibuff support to bpf_prog_test_run_xdp() Lorenzo Bianconi
2021-09-10 16:14 ` [PATCH v14 bpf-next 15/18] bpf: test_run: add xdp_shared_info pointer in bpf_test_finish signature Lorenzo Bianconi
2021-09-10 16:14 ` [PATCH v14 bpf-next 16/18] bpf: update xdp_adjust_tail selftest to include multi-buffer Lorenzo Bianconi
2021-09-10 16:14 ` [PATCH v14 bpf-next 17/18] net: xdp: introduce bpf_xdp_adjust_data helper Lorenzo Bianconi
2021-09-10 16:14 ` [PATCH v14 bpf-next 18/18] bpf: add bpf_xdp_adjust_data selftest Lorenzo Bianconi
2021-09-16 16:55 ` [PATCH v14 bpf-next 00/18] mvneta: introduce XDP multi-buffer support Jakub Kicinski
2021-09-17 14:51 ` Lorenzo Bianconi
2021-09-17 18:33 ` Jakub Kicinski
2021-09-17 18:43 ` Alexei Starovoitov
2021-09-17 19:00 ` Jakub Kicinski
2021-09-17 19:10 ` Alexei Starovoitov
2021-09-17 22:07 ` John Fastabend
2021-09-18 11:53 ` Toke Høiland-Jørgensen
2021-09-20 18:02 ` Jakub Kicinski
2021-09-20 21:01 ` Toke Høiland-Jørgensen
2021-09-20 21:25 ` Jakub Kicinski
2021-09-20 22:44 ` Toke Høiland-Jørgensen
2021-09-21 10:03 ` Eelco Chaudron
2021-09-28 11:48 ` Magnus Karlsson
2021-09-29 10:36 ` Lorenz Bauer
2021-09-29 12:25 ` Toke Høiland-Jørgensen
2021-09-29 12:32 ` Lorenz Bauer
2021-09-29 17:48 ` Jakub Kicinski
2021-09-29 17:46 ` Jakub Kicinski
2021-09-29 10:41 ` Lorenz Bauer [this message]
2021-09-29 12:10 ` Toke Høiland-Jørgensen
2021-09-29 12:38 ` Lorenz Bauer
2021-09-29 18:54 ` Alexei Starovoitov
2021-09-29 19:22 ` Jakub Kicinski
2021-09-29 20:39 ` Toke Høiland-Jørgensen
2021-10-01 9:03 ` Lorenzo Bianconi
2021-10-01 18:35 ` Jakub Kicinski
2021-10-06 9:32 ` Lorenzo Bianconi
2021-10-06 10:08 ` Eelco Chaudron
2021-10-06 12:15 ` Lorenzo Bianconi
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