Re: [PATCH iwl-next v5 3/3] igb: allow configuring RSS key via ethtool set_rxfh

[Kohei Enju <kohei@enjuk.jp>]

On Tue, 27 Jan 2026 17:54:10 +0900, Takashi Kozu wrote:

> Change igc_set_rxfh() to accept and save a userspace-provided
> RSS key. When a key is provided, store it in the adapter and write the
> E1000 registers accordingly.
> 
> This can be tested using `ethtool -X <dev> hkey <key>`.
> 
> Signed-off-by: Takashi Kozu <takkozu@amazon.com>

Tested with Intel Corporation I350 Gigabit Network Connection and
confirmed that toeplitz.py and test_rxfh_nl_set_key in rss_api.py
succeeded.

 # tools/testing/selftests/drivers/net/hw/toeplitz.py | grep -E "^# Totals"
 # Totals: pass:12 fail:0 xfail:0 xpass:0 skip:0 error:0

 # tools/testing/selftests/drivers/net/hw/rss_api.py | grep test_rxfh_nl_set_key
 ok 6 rss_api.test_rxfh_nl_set_key

Also checked that RSS hash key remains through admin down & up.
 # ethtool -X $DEV hkey be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef
 # ethtool -x $DEV | grep key -A 1
 RSS hash key:
 be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef
 # ip link set dev $DEV down && ip link set dev $DEV up
 # ethtool -x $DEV | grep key -A 1
 RSS hash key:
 be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef:be:ef

Tested-by: Kohei Enju <kohei@enjuk.jp>

Note: 
Toeplitz test needs correct handling of setting skb->hash and its rss
type, so I applied the patch below in advance.

https://lore.kernel.org/intel-wired-lan/20260122134809.7765-1-kohei@enjuk.jp/