From: John Fastabend <john.fastabend@gmail.com>
To: Eelco Chaudron <echaudro@redhat.com>,
John Fastabend <john.fastabend@gmail.com>
Cc: Lorenzo Bianconi <lorenzo@kernel.org>,
bpf@vger.kernel.org, netdev@vger.kernel.org,
lorenzo.bianconi@redhat.com, davem@davemloft.net,
kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net,
shayagr@amazon.com, sameehj@amazon.com, dsahern@kernel.org,
brouer@redhat.com, jasowang@redhat.com,
alexander.duyck@gmail.com, saeed@kernel.org,
maciej.fijalkowski@intel.com, magnus.karlsson@intel.com,
tirthendu.sarkar@intel.com
Subject: Re: [PATCH v9 bpf-next 10/14] bpf: add multi-buffer support to xdp copy helpers
Date: Thu, 24 Jun 2021 07:28:32 -0700 [thread overview]
Message-ID: <60d49690a87ae_2e84a2082c@john-XPS-13-9370.notmuch> (raw)
In-Reply-To: <34E2BF41-03E0-4DEC-ABF3-72C8FF7B4E4A@redhat.com>
Eelco Chaudron wrote:
>
>
> On 23 Jun 2021, at 1:49, John Fastabend wrote:
>
> > Lorenzo Bianconi wrote:
> >> From: Eelco Chaudron <echaudro@redhat.com>
> >>
> >> This patch adds support for multi-buffer for the following helpers:
> >> - bpf_xdp_output()
> >> - bpf_perf_event_output()
> >>
> >> Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
> >> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> >> ---
> >
> > Ah ok so at least xdp_output will work with all bytes. But this is
> > getting close to having access into the frags so I think doing
> > the last bit shouldn't be too hard?
>
>
> Guess you are talking about multi-buffer access in the XDP program?
>
> I did suggest an API a while back, https://lore.kernel.org/bpf/FD3E6E08-DE78-4FBA-96F6-646C93E88631@redhat.com/ but I had/have not time to work on it. Guess the difficult part is to convince the verifier to allow the data to be accessed.
Ah great I think we had the same idea I called it xdp_pull_data()
though.
Whats the complication though it looks like it can be done by simply
moving the data and data_end pointers around then marking them
invalidated. This way the verifier knows the program needs to
rewrite them. I can probably look more into next week.
From my first glance it looks relatively straight forward to do
now. I really would like to avoid yet another iteration of
programs features I have to discover and somehow work around
if we can get the helper into this series. If you really don't
have time I can probably take a look early next week on an
RFC for something like above helper.
.John
next prev parent reply other threads:[~2021-06-24 14:28 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-14 12:49 [PATCH v9 bpf-next 00/14] mvneta: introduce XDP multi-buffer support Lorenzo Bianconi
2021-06-14 12:49 ` [PATCH v9 bpf-next 01/14] net: skbuff: add data_len field to skb_shared_info Lorenzo Bianconi
2021-06-28 19:58 ` Alexander Duyck
2021-06-29 12:44 ` Lorenzo Bianconi
2021-06-29 17:08 ` Jakub Kicinski
2021-06-29 18:18 ` Alexander Duyck
2021-06-29 18:37 ` Jakub Kicinski
2021-06-29 19:11 ` Jesper Dangaard Brouer
2021-06-29 19:18 ` Lorenzo Bianconi
2021-06-29 20:45 ` Alexander Duyck
2021-06-14 12:49 ` [PATCH v9 bpf-next 02/14] xdp: introduce flags field in xdp_buff/xdp_frame Lorenzo Bianconi
2021-06-28 20:14 ` Alexander Duyck
2021-06-29 12:43 ` Lorenzo Bianconi
2021-06-29 13:07 ` Alexander Duyck
2021-06-29 13:25 ` Lorenzo Bianconi
2021-07-05 15:52 ` Lorenzo Bianconi
2021-07-05 21:35 ` Alexander Duyck
2021-07-06 11:53 ` Lorenzo Bianconi
2021-07-06 14:04 ` Alexander Duyck
2021-07-06 17:47 ` Lorenzo Bianconi
2021-06-14 12:49 ` [PATCH v9 bpf-next 03/14] net: mvneta: update mb bit before passing the xdp buffer to eBPF layer Lorenzo Bianconi
2021-06-14 12:49 ` [PATCH v9 bpf-next 04/14] xdp: add multi-buff support to xdp_return_{buff/frame} Lorenzo Bianconi
2021-06-14 12:49 ` [PATCH v9 bpf-next 05/14] net: mvneta: add multi buffer support to XDP_TX Lorenzo Bianconi
2021-06-14 12:49 ` [PATCH v9 bpf-next 06/14] net: mvneta: enable jumbo frames for XDP Lorenzo Bianconi
2021-06-14 12:49 ` [PATCH v9 bpf-next 07/14] net: xdp: add multi-buff support to xdp_build_skb_from_frame Lorenzo Bianconi
2021-06-28 21:05 ` Alexander Duyck
2021-06-29 18:34 ` Lorenzo Bianconi
2021-06-14 12:49 ` [PATCH v9 bpf-next 08/14] bpf: add multi-buff support to the bpf_xdp_adjust_tail() API Lorenzo Bianconi
2021-06-22 23:37 ` John Fastabend
2021-06-24 9:26 ` Eelco Chaudron
2021-06-24 14:24 ` John Fastabend
2021-06-24 15:16 ` Zvi Effron
2021-06-29 13:19 ` Lorenzo Bianconi
2021-06-29 13:27 ` Toke Høiland-Jørgensen
2021-07-06 21:44 ` Backwards compatibility for XDP multi-buff (was: Re: [PATCH v9 bpf-next 08/14] bpf: add multi-buff support to the bpf_xdp_adjust_tail() API) Toke Høiland-Jørgensen
2021-06-14 12:49 ` [PATCH v9 bpf-next 09/14] bpf: introduce bpf_xdp_get_buff_len helper Lorenzo Bianconi
2021-06-14 12:49 ` [PATCH v9 bpf-next 10/14] bpf: add multi-buffer support to xdp copy helpers Lorenzo Bianconi
2021-06-22 23:49 ` John Fastabend
2021-06-24 9:42 ` Eelco Chaudron
2021-06-24 14:28 ` John Fastabend [this message]
2021-06-25 8:25 ` Eelco Chaudron
2021-06-29 13:23 ` Lorenzo Bianconi
2021-07-06 10:15 ` Eelco Chaudron
2021-06-14 12:49 ` [PATCH v9 bpf-next 11/14] bpf: move user_size out of bpf_test_init Lorenzo Bianconi
2021-06-14 12:49 ` [PATCH v9 bpf-next 12/14] bpf: introduce multibuff support to bpf_prog_test_run_xdp() Lorenzo Bianconi
2021-06-14 12:49 ` [PATCH v9 bpf-next 13/14] bpf: test_run: add xdp_shared_info pointer in bpf_test_finish signature Lorenzo Bianconi
2021-06-14 12:49 ` [PATCH v9 bpf-next 14/14] bpf: update xdp_adjust_tail selftest to include multi-buffer Lorenzo Bianconi
2021-06-22 23:18 ` [PATCH v9 bpf-next 00/14] mvneta: introduce XDP multi-buffer support John Fastabend
2021-06-23 3:41 ` David Ahern
2021-06-23 5:48 ` John Fastabend
2021-06-23 14:40 ` David Ahern
2021-06-24 14:22 ` John Fastabend
2021-07-01 7:56 ` Magnus Karlsson
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