From: Jakub Kicinski <kuba@kernel.org>
To: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Cc: netdev@vger.kernel.org, bpf@vger.kernel.org,
magnus.karlsson@intel.com, stfomichev@gmail.com,
pabeni@redhat.com, horms@kernel.org, larysa.zaremba@intel.com,
aleksander.lobakin@intel.com, bjorn@kernel.org
Subject: Re: [PATCH v6 net 4/8] xsk: validate MTU against usable frame size on bind
Date: Fri, 3 Apr 2026 17:03:57 -0700 [thread overview]
Message-ID: <20260403170357.14cb166a@kernel.org> (raw)
In-Reply-To: <20260402154958.562179-5-maciej.fijalkowski@intel.com>
On Thu, 2 Apr 2026 17:49:54 +0200 Maciej Fijalkowski wrote:
> AF_XDP bind currently accepts zero-copy pool configurations without
> verifying that the device MTU fits into the usable frame space provided
> by the UMEM chunk.
>
> This becomes a problem since we started to respect tailroom which is
> subtracted from chunk_size (among with headroom). 2k chunk size might
> not provide enough space for standard 1500 MTU, so let us catch such
> settings at bind time. Furthermore, validate whether underlying HW will
> be able to satisfy configured MTU wrt XSK's frame size multiplied by
> supported Rx buffer chain length (that is exposed via
> net_device::xdp_zc_max_segs).
For multi-buf - I suppose it's fine, but wouldn't this be potentially
a regression for setups which use single buf? Suddenly we expect the
user to provide space for shinfo which was not part of the initial
AF_XDP design?
next prev parent reply other threads:[~2026-04-04 0:03 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-02 15:49 [PATCH v6 net 0/8] xsk: tailroom reservation and MTU validation Maciej Fijalkowski
2026-04-02 15:49 ` [PATCH v6 net 1/8] xsk: tighten UMEM headroom validation to account for tailroom and min frame Maciej Fijalkowski
2026-04-04 0:01 ` Jakub Kicinski
2026-04-04 10:07 ` Maciej Fijalkowski
2026-04-02 15:49 ` [PATCH v6 net 2/8] xsk: respect tailroom for ZC setups Maciej Fijalkowski
2026-04-02 15:49 ` [PATCH v6 net 3/8] xsk: fix XDP_UMEM_SG_FLAG issues Maciej Fijalkowski
2026-04-03 23:56 ` Jakub Kicinski
2026-04-04 10:11 ` Maciej Fijalkowski
2026-04-07 1:45 ` Jakub Kicinski
2026-04-02 15:49 ` [PATCH v6 net 4/8] xsk: validate MTU against usable frame size on bind Maciej Fijalkowski
2026-04-04 0:03 ` Jakub Kicinski [this message]
2026-04-04 10:02 ` Maciej Fijalkowski
2026-04-06 18:00 ` Jakub Kicinski
2026-04-02 15:49 ` [PATCH v6 net 5/8] selftests: bpf: introduce a common routine for reading procfs Maciej Fijalkowski
2026-04-02 15:49 ` [PATCH v6 net 6/8] selftests: bpf: fix pkt grow tests Maciej Fijalkowski
2026-04-02 15:49 ` [PATCH v6 net 7/8] selftests: bpf: have a separate variable for drop test Maciej Fijalkowski
2026-04-02 15:49 ` [PATCH v6 net 8/8] selftests: bpf: adjust rx_dropped xskxceiver's test to respect tailroom Maciej Fijalkowski
2026-04-07 1:50 ` [PATCH v6 net 0/8] xsk: tailroom reservation and MTU validation patchwork-bot+netdevbpf
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