Re: [PATCH iwl-next,v2 1/1] igc: Add wildcard rule support to ethtool NFC using Default Queue

[Brett Creeley]

On 6/19/2025 8:37 AM, Song Yoong Siang wrote:
> Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding.
>
>
> Introduce support for a lowest priority wildcard (catch-all) rule in
> ethtool's Network Flow Classification (NFC) for the igc driver. The
> wildcard rule directs all unmatched network traffic, including traffic not
> captured by Receive Side Scaling (RSS), to a specified queue. This
> functionality utilizes the Default Queue feature available in I225/I226
> hardware.
>
> The implementation has been validated on Intel ADL-S systems with two
> back-to-back connected I226 network interfaces.
>
> Testing Procedure:
> 1. On the Device Under Test (DUT), verify the initial statistic:
>     $ ethtool -S enp1s0 | grep rx_q.*packets
>          rx_queue_0_packets: 0
>          rx_queue_1_packets: 0
>          rx_queue_2_packets: 0
>          rx_queue_3_packets: 0
>
> 2. From the Link Partner, send 10 ARP packets:
>     $ arping -c 10 -I enp170s0 169.254.1.2
>
> 3. On the DUT, verify the packet reception on Queue 0:
>     $ ethtool -S enp1s0 | grep rx_q.*packets
>          rx_queue_0_packets: 10
>          rx_queue_1_packets: 0
>          rx_queue_2_packets: 0
>          rx_queue_3_packets: 0
>
> 4. On the DUT, add a wildcard rule to route all packets to Queue 3:
>     $ sudo ethtool -N enp1s0 flow-type ether queue 3
>
> 5. From the Link Partner, send another 10 ARP packets:
>     $ arping -c 10 -I enp170s0 169.254.1.2
>
> 6. Now, packets are routed to Queue 3 by the wildcard (Default Queue) rule:
>     $ ethtool -S enp1s0 | grep rx_q.*packets
>          rx_queue_0_packets: 10
>          rx_queue_1_packets: 0
>          rx_queue_2_packets: 0
>          rx_queue_3_packets: 10
>
> 7. On the DUT, add a EtherType rule to route ARP packet to Queue 1:
>     $ sudo ethtool -N enp1s0 flow-type ether proto 0x0806 queue 1
>
> 8. From the Link Partner, send another 10 ARP packets:
>     $ arping -c 10 -I enp170s0 169.254.1.2
>
> 9. Now, packets are routed to Queue 1 by the EtherType rule because it is
>     higher priority than the wildcard (Default Queue) rule:
>     $ ethtool -S enp1s0 | grep rx_q.*packets
>          rx_queue_0_packets: 10
>          rx_queue_1_packets: 10
>          rx_queue_2_packets: 0
>          rx_queue_3_packets: 10
>
> 10. On the DUT, delete all the NFC rules:
>      $ sudo ethtool -N enp1s0 delete 63
>      $ sudo ethtool -N enp1s0 delete 64
>
> 11. From the Link Partner, send another 10 ARP packets:
>      $ arping -c 10 -I enp170s0 169.254.1.2
>
> 12. Now, packets are routed to Queue 0 because the value of Default Queue
>      is reset back to 0:
>      $ ethtool -S enp1s0 | grep rx_q.*packets
>           rx_queue_0_packets: 20
>           rx_queue_1_packets: 10
>           rx_queue_2_packets: 0
>           rx_queue_3_packets: 10
>
> Co-developed-by: Blanco Alcaine Hector <hector.blanco.alcaine@xxxxxxxxx>
> Signed-off-by: Blanco Alcaine Hector <hector.blanco.alcaine@xxxxxxxxx>
> Signed-off-by: Song Yoong Siang <yoong.siang.song@xxxxxxxxx>
> ---
> V2:
>    - use Ethtool wildcard rule instead of extra uAPI (Jakub Kicinski & Jacob Keller)
>    - combine MRQC register definitions into a single location (Kurt Kanzenbach)
>    - use FIELD_PREP (Kurt Kanzenbach)
>    - use RCT rule (Wojciech Drewek)
>    - no need brackets for single line code (Wojciech Drewek)
>    - use imperative mood in commit message (Marcin Szycik)
>    - ensure igc_ prefix in function name (Marcin Szycik)
>
> V1: https://patchwork.ozlabs.org/project/intel-wired-lan/cover/20240730012212.775814-1-yoong.siang.song@xxxxxxxxx/
> ---
>   drivers/net/ethernet/intel/igc/igc.h         | 15 ++++++-------
>   drivers/net/ethernet/intel/igc/igc_defines.h |  4 ++++
>   drivers/net/ethernet/intel/igc/igc_ethtool.c | 18 ++++++++++++++++
>   drivers/net/ethernet/intel/igc/igc_main.c    | 22 ++++++++++++++++++++
>   4 files changed, 52 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/igc/igc.h b/drivers/net/ethernet/intel/igc/igc.h
> index 1525ae25fd3e..c580ecc954be 100644
> --- a/drivers/net/ethernet/intel/igc/igc.h
> +++ b/drivers/net/ethernet/intel/igc/igc.h
> @@ -406,10 +406,6 @@ extern char igc_driver_name[];
>   #define IGC_FLAG_RSS_FIELD_IPV4_UDP    BIT(6)
>   #define IGC_FLAG_RSS_FIELD_IPV6_UDP    BIT(7)
>
> -#define IGC_MRQC_ENABLE_RSS_MQ         0x00000002
> -#define IGC_MRQC_RSS_FIELD_IPV4_UDP    0x00400000
> -#define IGC_MRQC_RSS_FIELD_IPV6_UDP    0x00800000
> -

Small nit, but moving these fields seems like a separate patch since 
moving them isn't part of the wildcard rule changes.

Thanks,

Brett

>   /* RX-desc Write-Back format RSS Type's */
>   enum igc_rss_type_num {
>          IGC_RSS_TYPE_NO_HASH            = 0,
> @@ -635,6 +631,7 @@ enum igc_filter_match_flags {
>          IGC_FILTER_FLAG_DST_MAC_ADDR =  BIT(3),
>          IGC_FILTER_FLAG_USER_DATA =     BIT(4),
>          IGC_FILTER_FLAG_VLAN_ETYPE =    BIT(5),
> +       IGC_FILTER_FLAG_DEFAULT_QUEUE = BIT(6),
>   };

<snip>