> -----Original Message-----
> From: Larysa Zaremba <larysa.zare...@intel.com>
> Sent: Friday, April 26, 2024 8:41 AM
> To: Nguyen, Anthony L <anthony.l.ngu...@intel.com>; intel-wired-
> l...@lists.osuosl.org; linux-ker...@vger.kernel.org; net...@vger.kernel.org
> Cc: Zaremba, Larysa <larysa.zare...@intel.com>; Brady, Alan
> <alan.br...@intel.com>; Fijalkowski, Maciej <maciej.fijalkow...@intel.com>;
> Brandeburg, Jesse <jesse.brandeb...@intel.com>; Tantilov, Emil S
> <emil.s.tanti...@intel.com>; Linga, Pavan Kumar
> <pavan.kumar.li...@intel.com>; Hay, Joshua A <joshua.a....@intel.com>;
> Kitszel, Przemyslaw <przemyslaw.kits...@intel.com>; Bagnucki, Igor
> <igor.bagnu...@intel.com>
> Subject: [PATCH iwl-net] idpf: Interpret .set_channels() input differently
>
> Unlike ice, idpf does not check, if user has requested at least 1 combined
> channel. Instead, it relies on a check in the core code. Unfortunately, the
> check does not trigger for us because of the hacky .set_channels()
> interpretation logic that is not consistent with the core code.
>
> This naturally leads to user being able to trigger a crash with an invalid
> input. This is how:
>
> 1. ethtool -l <IFNAME> -> combined: 40
> 2. ethtool -L <IFNAME> rx 0 tx 0
> combined number is not specified, so command becomes {rx_count = 0,
> tx_count = 0, combined_count = 40}.
> 3. ethnl_set_channels checks, if there is at least 1 RX and 1 TX channel,
> comparing (combined_count + rx_count) and (combined_count + tx_count)
> to zero. Obviously, (40 + 0) is greater than zero, so the core code
> deems the input OK.
> 4. idpf interprets `rx 0 tx 0` as 0 channels and tries to proceed with such
> configuration.
>
> The issue has to be solved fundamentally, as current logic is also known to
> cause AF_XDP problems in ice [0].
>
> Interpret the command in a way that is more consistent with ethtool
> manual [1] (--show-channels and --set-channels) and new ice logic.
>
> Considering that in the idpf driver only the difference between RX and TX
> queues forms dedicated channels, change the correct way to set number of
> channels to:
>
> ethtool -L <IFNAME> combined 10 /* For symmetric queues */
> ethtool -L <IFNAME> combined 8 tx 2 rx 0 /* For asymmetric queues */
>
> [0] https://lore.kernel.org/netdev/20240418095857.2827-1-
> larysa.zare...@intel.com/
> [1] https://man7.org/linux/man-pages/man8/ethtool.8.html
>
> Fixes: 02cbfba1add5 ("idpf: add ethtool callbacks")
> Reviewed-by: Przemek Kitszel <przemyslaw.kits...@intel.com>
> Reviewed-by: Igor Bagnucki <igor.bagnu...@intel.com>
> Signed-off-by: Larysa Zaremba <larysa.zare...@intel.com>
> ---
> .../net/ethernet/intel/idpf/idpf_ethtool.c | 21 ++++++-------------
> 1 file changed, 6 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/idpf/idpf_ethtool.c
> b/drivers/net/ethernet/intel/idpf/idpf_ethtool.c
> index 986d429d1175..1cf3067a9c31 100644
> --- a/drivers/net/ethernet/intel/idpf/idpf_ethtool.c
> +++ b/drivers/net/ethernet/intel/idpf/idpf_ethtool.c
Tested-by: Krishneil Singh <krishneil.k.si...@intel.com>
