netdev - Re: [PATCH iwl-next v8 06/11] igc: set the RX packet buffer size for TSN mode

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250305225803.kozn26ilnrnjrgbz@skbuf>
Date: Thu, 6 Mar 2025 00:58:03 +0200
From: Vladimir Oltean <vladimir.oltean@....com>
To: Faizal Rahim <faizal.abdul.rahim@...ux.intel.com>
Cc: Tony Nguyen <anthony.l.nguyen@...el.com>,
	Przemek Kitszel <przemyslaw.kitszel@...el.com>,
	Andrew Lunn <andrew+netdev@...n.ch>,
	"David S . Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Maxime Coquelin <mcoquelin.stm32@...il.com>,
	Alexandre Torgue <alexandre.torgue@...s.st.com>,
	Simon Horman <horms@...nel.org>,
	Russell King <linux@...linux.org.uk>,
	Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	Jesper Dangaard Brouer <hawk@...nel.org>,
	John Fastabend <john.fastabend@...il.com>,
	Furong Xu <0x1207@...il.com>,
	Russell King <rmk+kernel@...linux.org.uk>,
	Serge Semin <fancer.lancer@...il.com>,
	Xiaolei Wang <xiaolei.wang@...driver.com>,
	Suraj Jaiswal <quic_jsuraj@...cinc.com>,
	Kory Maincent <kory.maincent@...tlin.com>,
	Gal Pressman <gal@...dia.com>,
	Jesper Nilsson <jesper.nilsson@...s.com>,
	Choong Yong Liang <yong.liang.choong@...ux.intel.com>,
	Chwee-Lin Choong <chwee.lin.choong@...el.com>,
	Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>,
	Vinicius Costa Gomes <vinicius.gomes@...el.com>,
	intel-wired-lan@...ts.osuosl.org, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-stm32@...md-mailman.stormreply.com,
	linux-arm-kernel@...ts.infradead.org, bpf@...r.kernel.org
Subject: Re: [PATCH iwl-next v8 06/11] igc: set the RX packet buffer size for
 TSN mode

On Wed, Mar 05, 2025 at 08:00:21AM -0500, Faizal Rahim wrote:
> In preparation for supporting frame preemption, when entering TSN mode
> set the receive packet buffer to 16KB for the Express MAC, 16KB for
> the Preemptible MAC and 2KB for the BMC, according to the datasheet
> section 7.1.3.2.
> 
> Co-developed-by: Vinicius Costa Gomes <vinicius.gomes@...el.com>
> Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@...el.com>
> Signed-off-by: Faizal Rahim <faizal.abdul.rahim@...ux.intel.com>
> ---
>  drivers/net/ethernet/intel/igc/igc_defines.h |  3 +++
>  drivers/net/ethernet/intel/igc/igc_tsn.c     | 13 +++++++++++--
>  2 files changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/igc/igc_defines.h b/drivers/net/ethernet/intel/igc/igc_defines.h
> index 516ef70c98e9..b19ac6f30dac 100644
> --- a/drivers/net/ethernet/intel/igc/igc_defines.h
> +++ b/drivers/net/ethernet/intel/igc/igc_defines.h
> @@ -402,6 +402,9 @@
>  
>   /* 7KB bytes buffer for each tx queue (total 4 queues) + 4KB for BMC*/
>  #define IGC_TXPBSIZE_TSN	0x041c71c7
> +/* 15KB for EXP + 15KB for BE + 2KB for BMC */
> +#define IGC_RXPBSIZE_TSN	0x0000f08f
> +#define IGC_RXPBSIZE_SIZE_MASK	0x0001FFFF

Does 0x0000f08f have any further meaning, does it represent anything
bitwise? (similar question for IGC_TXPBSIZE_TSN in the previous patch).
I don't see the correlation between the values mentioned in the comment
and the magic constant. If RXPBPSIZE has a bitwise meaning, maybe you
could rewrite the magic value with macros for each field.