[PATCH iwl-next v5 0/3] igb: add RSS key get/set support

[PATCH iwl-next v5 0/3] igb: add RSS key get/set support

[Takashi Kozu]

This series adds ethtool get/set support for the RSS hash key in the igb
driver.
- `ethtool -x <dev>` to display the RSS key
- `ethtool -X <dev> hkey <key>` to configure the RSS key

Without patch:

# ethtool -x $DEV | grep key -A1
RSS hash key:
Operation not supported
# ethtool -X $DEV hkey 00:00:00:00:00:00:00:00:00:00:00:00:000
Cannot set RX flow hash configuration:
  Hash key setting not supported


With patch:

# ethtool -x $DEV | grep key -A1
RSS hash key:
86:5d:11:56:bd:6f:20:38:3b:f8:bb:df:00:3a:b0:24:95:9f:f9:f4:25:a3:01:3e:4a:15:d6:7c:4d:af:39:7e:4a:95:f2:fd:f6:b6:26:f7

# ethtool -X $DEV hkey 00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00
# ethtool -x $DEV | grep key -A1
RSS hash key:
00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00

<Changelog>
  v5:
      - delete 'has_user_rss_key' flag because it's unnecessary. 

  v4: 
      - modify the position of the declaration in the igb_write_rss_key() so that it is at the start of the block.

  v3: 
      - add ASSERT_RTNL() to explicitly show that an rtnl lock is being used
      - Move netdev_rss_key_fill() function from igb_setup_mrqc() to igb_sw_init()
      - Add kernel-doc header to igb_write_rss_key()

      <Test>
      - tools/testing/selftests/drivers/net/hw/rss_api.py is successful
      Run the following command

      # NETIF=enp0s3 python tools/testing/selftests/drivers/net/hw/rss_api.py | grep -v "# Exception" 

      Then, I checked the diffs before and after applying the patch

      $ diff beforePatch.txt afterPatch.txt 
      9c9
      < not ok 6 rss_api.test_rxfh_nl_set_key
      ---
      > ok 6 rss_api.test_rxfh_nl_set_key
      16c16
      < # Totals: pass:4 fail:8 xfail:0 xpass:0 skip:0 error:0
      ---
      > # Totals: pass:5 fail:7 xfail:0 xpass:0 skip:0 error:0

      The failing tests originally fails due to hardware.

      - tools/testing/selftests/drivers/net/hw/toeplitz.py is untested since there is no actual hardware, but since the logic around wr32() is preserved as it is, key writing to the device remain the same.
      

  v2: Fix typos (igc_* → igb_*) 
      https://lore.kernel.org/intel-wired-lan/20260108052020.84218-5-takkozu@amazon.com/T/

  v1: https://lore.kernel.org/all/20251205082106.4028-5-takkozu@amazon.com/

Takashi Kozu (3):
  igb: prepare for RSS key get/set support
  igb: expose RSS key via ethtool get_rxfh
  igb: allow configuring RSS key via ethtool set_rxfh

 drivers/net/ethernet/intel/igb/igb.h         |  3 +
 drivers/net/ethernet/intel/igb/igb_ethtool.c | 85 ++++++++++++++------
 drivers/net/ethernet/intel/igb/igb_main.c    |  8 +-
 3 files changed, 66 insertions(+), 30 deletions(-)

-- 
2.52.0

[PATCH iwl-next v5 1/3] igb: prepare for RSS key get/set support

[Takashi Kozu]

Store the RSS key inside struct igb_adapter and introduce the
igb_write_rss_key() helper function. This allows the driver to program
the E1000 registers using a persistent RSS key, instead of using a
stack-local buffer in igb_setup_mrqc().

Reviewed-by: Piotr Kwapulinski <piotr.kwapulinski@intel.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Takashi Kozu <takkozu@amazon.com>
---
 drivers/net/ethernet/intel/igb/igb.h         |  3 +++
 drivers/net/ethernet/intel/igb/igb_ethtool.c | 21 ++++++++++++++++++++
 drivers/net/ethernet/intel/igb/igb_main.c    |  8 ++++----
 3 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h
index 0fff1df81b7b..8c9b02058cec 100644
--- a/drivers/net/ethernet/intel/igb/igb.h
+++ b/drivers/net/ethernet/intel/igb/igb.h
@@ -495,6 +495,7 @@ struct hwmon_buff {
 #define IGB_N_PEROUT	2
 #define IGB_N_SDP	4
 #define IGB_RETA_SIZE	128
+#define IGB_RSS_KEY_SIZE	40
 
 enum igb_filter_match_flags {
 	IGB_FILTER_FLAG_ETHER_TYPE = 0x1,
@@ -655,6 +656,7 @@ struct igb_adapter {
 	struct i2c_client *i2c_client;
 	u32 rss_indir_tbl_init;
 	u8 rss_indir_tbl[IGB_RETA_SIZE];
+	u8 rss_key[IGB_RSS_KEY_SIZE];
 
 	unsigned long link_check_timeout;
 	int copper_tries;
@@ -735,6 +737,7 @@ void igb_down(struct igb_adapter *);
 void igb_reinit_locked(struct igb_adapter *);
 void igb_reset(struct igb_adapter *);
 int igb_reinit_queues(struct igb_adapter *);
+void igb_write_rss_key(struct igb_adapter *adapter);
 void igb_write_rss_indir_tbl(struct igb_adapter *);
 int igb_set_spd_dplx(struct igb_adapter *, u32, u8);
 int igb_setup_tx_resources(struct igb_ring *);
diff --git a/drivers/net/ethernet/intel/igb/igb_ethtool.c b/drivers/net/ethernet/intel/igb/igb_ethtool.c
index b507576b28b2..a93069b761a6 100644
--- a/drivers/net/ethernet/intel/igb/igb_ethtool.c
+++ b/drivers/net/ethernet/intel/igb/igb_ethtool.c
@@ -3019,6 +3019,27 @@ static int igb_set_rxnfc(struct net_device *dev, struct ethtool_rxnfc *cmd)
 	return ret;
 }
 
+/**
+ * igb_write_rss_key - Program the RSS key into device registers
+ * @adapter: board private structure
+ *
+ * Write the RSS key stored in adapter->rss_key to the E1000 hardware registers.
+ * Each 32-bit chunk of the key is read using get_unaligned_le32() and written
+ * to the appropriate register.
+ */
+void igb_write_rss_key(struct igb_adapter *adapter)
+{
+	struct e1000_hw *hw = &adapter->hw;
+
+	ASSERT_RTNL();
+
+	for (int i = 0; i < IGB_RSS_KEY_SIZE / 4; i++) {
+		u32 val = get_unaligned_le32(&adapter->rss_key[i * 4]);
+
+		wr32(E1000_RSSRK(i), val);
+	}
+}
+
 static int igb_get_eee(struct net_device *netdev, struct ethtool_keee *edata)
 {
 	struct igb_adapter *adapter = netdev_priv(netdev);
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index dbea37269d2c..c703011b19ec 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -4050,6 +4050,9 @@ static int igb_sw_init(struct igb_adapter *adapter)
 
 	pci_read_config_word(pdev, PCI_COMMAND, &hw->bus.pci_cmd_word);
 
+	/* init RSS key */
+	netdev_rss_key_fill(adapter->rss_key, sizeof(adapter->rss_key));
+
 	/* set default ring sizes */
 	adapter->tx_ring_count = IGB_DEFAULT_TXD;
 	adapter->rx_ring_count = IGB_DEFAULT_RXD;
@@ -4525,11 +4528,8 @@ static void igb_setup_mrqc(struct igb_adapter *adapter)
 	struct e1000_hw *hw = &adapter->hw;
 	u32 mrqc, rxcsum;
 	u32 j, num_rx_queues;
-	u32 rss_key[10];
 
-	netdev_rss_key_fill(rss_key, sizeof(rss_key));
-	for (j = 0; j < 10; j++)
-		wr32(E1000_RSSRK(j), rss_key[j]);
+	igb_write_rss_key(adapter);
 
 	num_rx_queues = adapter->rss_queues;
 
-- 
2.52.0

[PATCH iwl-next v5 2/3] igb: expose RSS key via ethtool get_rxfh

[Takashi Kozu]

Implement igb_get_rxfh_key_size() and extend
igb_get_rxfh() to return the RSS key to userspace.

This can be tested using `ethtool -x <dev>`.

Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Takashi Kozu <takkozu@amazon.com>
---
 drivers/net/ethernet/intel/igb/igb_ethtool.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb_ethtool.c b/drivers/net/ethernet/intel/igb/igb_ethtool.c
index a93069b761a6..b387121f0ea7 100644
--- a/drivers/net/ethernet/intel/igb/igb_ethtool.c
+++ b/drivers/net/ethernet/intel/igb/igb_ethtool.c
@@ -3297,10 +3297,12 @@ static int igb_get_rxfh(struct net_device *netdev,
 	int i;
 
 	rxfh->hfunc = ETH_RSS_HASH_TOP;
-	if (!rxfh->indir)
-		return 0;
-	for (i = 0; i < IGB_RETA_SIZE; i++)
-		rxfh->indir[i] = adapter->rss_indir_tbl[i];
+	if (rxfh->indir)
+		for (i = 0; i < IGB_RETA_SIZE; i++)
+			rxfh->indir[i] = adapter->rss_indir_tbl[i];
+
+	if (rxfh->key)
+		memcpy(rxfh->key, adapter->rss_key, sizeof(adapter->rss_key));
 
 	return 0;
 }
@@ -3340,6 +3342,11 @@ void igb_write_rss_indir_tbl(struct igb_adapter *adapter)
 	}
 }
 
+static u32 igb_get_rxfh_key_size(struct net_device *netdev)
+{
+	return IGB_RSS_KEY_SIZE;
+}
+
 static int igb_set_rxfh(struct net_device *netdev,
 			struct ethtool_rxfh_param *rxfh,
 			struct netlink_ext_ack *extack)
@@ -3504,6 +3511,7 @@ static const struct ethtool_ops igb_ethtool_ops = {
 	.get_module_eeprom	= igb_get_module_eeprom,
 	.get_rxfh_indir_size	= igb_get_rxfh_indir_size,
 	.get_rxfh		= igb_get_rxfh,
+	.get_rxfh_key_size	= igb_get_rxfh_key_size,
 	.set_rxfh		= igb_set_rxfh,
 	.get_rxfh_fields	= igb_get_rxfh_fields,
 	.set_rxfh_fields	= igb_set_rxfh_fields,
-- 
2.52.0

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

[Takashi Kozu]

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>
---
 drivers/net/ethernet/intel/igb/igb_ethtool.c | 48 +++++++++++---------
 1 file changed, 26 insertions(+), 22 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb_ethtool.c b/drivers/net/ethernet/intel/igb/igb_ethtool.c
index b387121f0ea7..b4eef14c09d5 100644
--- a/drivers/net/ethernet/intel/igb/igb_ethtool.c
+++ b/drivers/net/ethernet/intel/igb/igb_ethtool.c
@@ -3357,35 +3357,39 @@ static int igb_set_rxfh(struct net_device *netdev,
 	u32 num_queues;
 
 	/* We do not allow change in unsupported parameters */
-	if (rxfh->key ||
-	    (rxfh->hfunc != ETH_RSS_HASH_NO_CHANGE &&
-	     rxfh->hfunc != ETH_RSS_HASH_TOP))
+	if (rxfh->hfunc != ETH_RSS_HASH_NO_CHANGE &&
+	    rxfh->hfunc != ETH_RSS_HASH_TOP)
 		return -EOPNOTSUPP;
-	if (!rxfh->indir)
-		return 0;
 
-	num_queues = adapter->rss_queues;
+	if (rxfh->indir) {
+		num_queues = adapter->rss_queues;
 
-	switch (hw->mac.type) {
-	case e1000_82576:
-		/* 82576 supports 2 RSS queues for SR-IOV */
-		if (adapter->vfs_allocated_count)
-			num_queues = 2;
-		break;
-	default:
-		break;
-	}
+		switch (hw->mac.type) {
+		case e1000_82576:
+			/* 82576 supports 2 RSS queues for SR-IOV */
+			if (adapter->vfs_allocated_count)
+				num_queues = 2;
+			break;
+		default:
+			break;
+		}
 
-	/* Verify user input. */
-	for (i = 0; i < IGB_RETA_SIZE; i++)
-		if (rxfh->indir[i] >= num_queues)
-			return -EINVAL;
+		/* Verify user input. */
+		for (i = 0; i < IGB_RETA_SIZE; i++)
+			if (rxfh->indir[i] >= num_queues)
+				return -EINVAL;
 
 
-	for (i = 0; i < IGB_RETA_SIZE; i++)
-		adapter->rss_indir_tbl[i] = rxfh->indir[i];
+		for (i = 0; i < IGB_RETA_SIZE; i++)
+			adapter->rss_indir_tbl[i] = rxfh->indir[i];
+
+		igb_write_rss_indir_tbl(adapter);
+	}
 
-	igb_write_rss_indir_tbl(adapter);
+	if (rxfh->key) {
+		memcpy(adapter->rss_key, rxfh->key, sizeof(adapter->rss_key));
+		igb_write_rss_key(adapter);
+	}
 
 	return 0;
 }
-- 
2.52.0

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

[Kohei Enju]

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/

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

[Simon Horman]

This is an AI-generated review of your patch. The human sending this
email says "I'm releasing this report for completeness. And while I
do think it is correct. I don't think it needs to block progress"

For local reproduction steps see https://netdev-ai.bots.linux.dev/ai-local.html
---
igb: allow configuring RSS key via ethtool set_rxfh

This patch adds support for configuring the RSS key via ethtool's
set_rxfh interface. The change accepts a userspace-provided RSS key,
stores it in the adapter structure, and writes it to hardware registers.

> Change igc_set_rxfh() to accept and save a userspace-provided
> RSS key.

This isn't a code bug, but the commit message references "igc_set_rxfh()"
when the function being modified is actually igb_set_rxfh() in
drivers/net/ethernet/intel/igb/igb_ethtool.c. This typo was noted by
Aleksandr Loktionov in the v1 review:
https://lore.kernel.org/intel-wired-lan/IA3PR11MB89860A16782937C7E8C2E2DEE5A7A@IA3PR11MB8986.namprd11.prod.outlook.com/

Should this be corrected to igb_set_rxfh() to match the actual code?

Re: [PATCH iwl-next v5 0/3] igb: add RSS key get/set support

[Simon Horman]

On Tue, Jan 27, 2026 at 05:54:07PM +0900, Takashi Kozu wrote:
> This series adds ethtool get/set support for the RSS hash key in the igb
> driver.
> - `ethtool -x <dev>` to display the RSS key
> - `ethtool -X <dev> hkey <key>` to configure the RSS key

...

Thanks,

The AI review automation did flag a typo in patch 3/3,
which I have released in the form of a response to that patch.

That notwithstanding, overall this series looks good to me.

Reviewed-by: Simon Horman <horms@kernel.org>

Re: [Intel-wired-lan] [iwl-next, v5, 3/3] igb: allow configuring RSS key via ethtool set_rxfh

[Takashi Kozu]

> From: Simon Horman <horms@kernel.org>
> To: takkozu@amazon.com
> Cc: Simon Horman <horms@kernel.org>,
> anthony.l.nguyen@intel.com, andrew+netdev@lunn.ch,
> davem@davemloft.net, aleksandr.loktionov@intel.com,
> przemyslaw.kitszel@intel.com, kuba@kernel.org,
> netdev@vger.kernel.org, enjuk@amazon.com, pabeni@redhat.com,
> intel-wired-lan@lists.osuosl.org, edumazet@google.com,
> piotr.kwapulinski@intel.com, pmenzel@molgen.mpg.de
> Subject: Re: [iwl-next,v5,3/3] igb: allow configuring RSS key via ethtool set_rxfh
> Date: Mon, 2 Feb 2026 10:25:20 +0000 [thread overview]
> Message-ID: <20260202102520.1844644-1-horms@kernel.org> (raw)
> In-Reply-To: <20260127085410.79645-8-takkozu@amazon.com>
> 
> This is an AI-generated review of your patch. The human sending this
> email says "I'm releasing this report for completeness. And while I
> do think it is correct. I don't think it needs to block progress"
> 
> For local reproduction steps see https://netdev-ai.bots.linux.dev/ai-local.html
> ---
> igb: allow configuring RSS key via ethtool set_rxfh
> 
> This patch adds support for configuring the RSS key via ethtool's
> set_rxfh interface. The change accepts a userspace-provided RSS key,
> stores it in the adapter structure, and writes it to hardware registers.
> 
> > Change igc_set_rxfh() to accept and save a userspace-provided
> > RSS key.
> 
> This isn't a code bug, but the commit message references "igc_set_rxfh()"
> when the function being modified is actually igb_set_rxfh() in
> drivers/net/ethernet/intel/igb/igb_ethtool.c. This typo was noted by
> Aleksandr Loktionov in the v1 review:
> https://lore.kernel.org/intel-wired-lan/IA3PR11MB89860A16782937C7E8C2E2DEE5A7A@IA3PR11MB8986.namprd11.prod.outlook.com/
> 
> Should this be corrected to igb_set_rxfh() to match the actual code?

Thank you for pointing out.
I'll fix it and send it as v6.