netdev - Re: [PATCH net-next 1/2] ethtool: Symmetric OR-XOR RSS hash

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: <08135b32-c516-7f6b-f7a1-e5179840281c@gmail.com>
Date: Mon, 3 Feb 2025 19:15:28 +0000
From: Edward Cree <ecree.xilinx@...il.com>
To: Gal Pressman <gal@...dia.com>, "David S. Miller" <davem@...emloft.net>,
 Jakub Kicinski <kuba@...nel.org>
Cc: netdev@...r.kernel.org, Eric Dumazet <edumazet@...gle.com>,
 Paolo Abeni <pabeni@...hat.com>, Simon Horman <horms@...nel.org>,
 Jonathan Corbet <corbet@....net>, Tony Nguyen <anthony.l.nguyen@...el.com>,
 Przemek Kitszel <przemyslaw.kitszel@...el.com>,
 Andrew Lunn <andrew+netdev@...n.ch>, Tariq Toukan <tariqt@...dia.com>,
 Ahmed Zaki <ahmed.zaki@...el.com>, linux-doc@...r.kernel.org,
 Cosmin Ratiu <cratiu@...dia.com>
Subject: Re: [PATCH net-next 1/2] ethtool: Symmetric OR-XOR RSS hash

On 03/02/2025 15:00, Gal Pressman wrote:
> Add an additional type of symmetric RSS hash type: OR-XOR.
> The "Symmetric-OR-XOR" algorithm transforms the input as follows:
> 
> (SRC_IP | DST_IP, SRC_IP ^ DST_IP, SRC_PORT | DST_PORT, SRC_PORT ^ DST_PORT)
> 
> Change 'cap_rss_sym_xor_supported' to 'supported_input_xfrm', a bitmap
> of supported RXH_XFRM_* types.
> 
> Reviewed-by: Cosmin Ratiu <cratiu@...dia.com>
> Reviewed-by: Tariq Toukan <tariqt@...dia.com>
> Signed-off-by: Gal Pressman <gal@...dia.com>
> ---
>  Documentation/networking/ethtool-netlink.rst   |  2 +-
>  Documentation/networking/scaling.rst           | 14 ++++++++++----
>  drivers/net/ethernet/intel/iavf/iavf_ethtool.c |  2 +-
>  drivers/net/ethernet/intel/ice/ice_ethtool.c   |  2 +-
>  include/linux/ethtool.h                        |  5 ++---
>  include/uapi/linux/ethtool.h                   |  7 ++++---
>  net/ethtool/ioctl.c                            |  8 ++++----
>  7 files changed, 23 insertions(+), 17 deletions(-)
> 
> diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
> index 3770a2294509..aba83d97ff90 100644
> --- a/Documentation/networking/ethtool-netlink.rst
> +++ b/Documentation/networking/ethtool-netlink.rst
> @@ -1934,7 +1934,7 @@ ETHTOOL_A_RSS_INDIR attribute returns RSS indirection table where each byte
>  indicates queue number.
>  ETHTOOL_A_RSS_INPUT_XFRM attribute is a bitmap indicating the type of
>  transformation applied to the input protocol fields before given to the RSS
> -hfunc. Current supported option is symmetric-xor.
> +hfunc. Current supported option is symmetric-xor and symmetric-or-xor.

"options are"?

> diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
> index d1089b88efc7..b10ecc503b26 100644
> --- a/include/uapi/linux/ethtool.h
> +++ b/include/uapi/linux/ethtool.h
> @@ -2263,12 +2263,13 @@ static inline int ethtool_validate_duplex(__u8 duplex)
>  #define WOL_MODE_COUNT		8
>  
>  /* RSS hash function data
> - * XOR the corresponding source and destination fields of each specified
> - * protocol. Both copies of the XOR'ed fields are fed into the RSS and RXHASH
> - * calculation. Note that this XORing reduces the input set entropy and could
> + * XOR/OR the corresponding source and destination fields of each specified
> + * protocol. Both copies of the XOR/OR'ed fields are fed into the RSS and RXHASH
> + * calculation. Note that this operation reduces the input set entropy and could
>   * be exploited to reduce the RSS queue spread.
>   */
>  #define	RXH_XFRM_SYM_XOR	(1 << 0)
> +#define	RXH_XFRM_SYM_OR_XOR	(1 << 1)
>  #define	RXH_XFRM_NO_CHANGE	0xff

I think this should be two separate comments, one on RXH_XFRM_SYM_XOR and
 one on RXH_XFRM_SYM_OR_XOR, so that you can untangle the phrasing a bit.
E.g. there isn't such a thing as "Both copies of the XOR/OR'ed fields"; one
 has two copies of XOR and the other has a XOR and an OR.
Second comment could be something like "Similar to SYM_XOR except that one
 copy of the XOR'ed fields is replaced by an OR of the same fields."

Apart from this, patch LGTM.