ethtool: Support for configurable RSS hash function

This patch extends the set/get_rxfh ethtool-options for getting or
setting the RSS hash function.

It modifies drivers implementation of set/get_rxfh accordingly.

This change also delegates the responsibility of checking whether a
modification to a certain RX flow hash parameter is supported to the
driver implementation of set_rxfh.

User-kernel API is done through the new hfunc bitmask field in the
ethtool_rxfh struct. A bit set in the hfunc field is corresponding to an
index in the new string-set ETH_SS_RSS_HASH_FUNCS.

Got approval from most of the relevant driver maintainers that their
driver is using Toeplitz, and for the few that didn't answered, also
assumed it is Toeplitz.

Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Ariel Elior <ariel.elior@qlogic.com>
Cc: Prashant Sreedharan <prashant@broadcom.com>
Cc: Michael Chan <mchan@broadcom.com>
Cc: Hariprasad S <hariprasad@chelsio.com>
Cc: Sathya Perla <sathya.perla@emulex.com>
Cc: Subbu Seetharaman <subbu.seetharaman@emulex.com>
Cc: Ajit Khaparde <ajit.khaparde@emulex.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Cc: Bruce Allan <bruce.w.allan@intel.com>
Cc: Carolyn Wyborny <carolyn.wyborny@intel.com>
Cc: Don Skidmore <donald.c.skidmore@intel.com>
Cc: Greg Rose <gregory.v.rose@intel.com>
Cc: Matthew Vick <matthew.vick@intel.com>
Cc: John Ronciak <john.ronciak@intel.com>
Cc: Mitch Williams <mitch.a.williams@intel.com>
Cc: Amir Vadai <amirv@mellanox.com>
Cc: Solarflare linux maintainers <linux-net-drivers@solarflare.com>
Cc: Shradha Shah <sshah@solarflare.com>
Cc: Shreyas Bhatewara <sbhatewara@vmware.com>
Cc: "VMware, Inc." <pv-drivers@vmware.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Eyal Perry <eyalpe@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/amd/xgbe/xgbe-ethtool.c

@@ -511,7 +511,8 @@ static u32 xgbe_get_rxfh_indir_size(struct net_device *netdev)
 	return ARRAY_SIZE(pdata->rss_table);
 }
 
-static int xgbe_get_rxfh(struct net_device *netdev, u32 *indir, u8 *key)
+static int xgbe_get_rxfh(struct net_device *netdev, u32 *indir, u8 *key,
+			 u8 *hfunc)
 {
 	struct xgbe_prv_data *pdata = netdev_priv(netdev);
 	unsigned int i;
@@ -525,16 +526,22 @@ static int xgbe_get_rxfh(struct net_device *netdev, u32 *indir, u8 *key)
 	if (key)
 		memcpy(key, pdata->rss_key, sizeof(pdata->rss_key));
 
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+
 	return 0;
 }
 
 static int xgbe_set_rxfh(struct net_device *netdev, const u32 *indir,
-			 const u8 *key)
+			 const u8 *key, const u8 hfunc)
 {
 	struct xgbe_prv_data *pdata = netdev_priv(netdev);
 	struct xgbe_hw_if *hw_if = &pdata->hw_if;
 	unsigned int ret;
 
+	if (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP)
+		return -EOPNOTSUPP;
+
 	if (indir) {
 		ret = hw_if->set_rss_lookup_table(pdata, indir);
 		if (ret)

drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c

@@ -3358,12 +3358,18 @@ static u32 bnx2x_get_rxfh_indir_size(struct net_device *dev)
 	return T_ETH_INDIRECTION_TABLE_SIZE;
 }
 
-static int bnx2x_get_rxfh(struct net_device *dev, u32 *indir, u8 *key)
+static int bnx2x_get_rxfh(struct net_device *dev, u32 *indir, u8 *key,
+			  u8 *hfunc)
 {
 	struct bnx2x *bp = netdev_priv(dev);
 	u8 ind_table[T_ETH_INDIRECTION_TABLE_SIZE] = {0};
 	size_t i;
 
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+	if (!indir)
+		return 0;
+
 	/* Get the current configuration of the RSS indirection table */
 	bnx2x_get_rss_ind_table(&bp->rss_conf_obj, ind_table);
 
@@ -3383,11 +3389,21 @@ static int bnx2x_get_rxfh(struct net_device *dev, u32 *indir, u8 *key)
 }
 
 static int bnx2x_set_rxfh(struct net_device *dev, const u32 *indir,
-			  const u8 *key)
+			  const u8 *key, const u8 hfunc)
 {
 	struct bnx2x *bp = netdev_priv(dev);
 	size_t i;
 
+	/* We require at least one supported parameter to be changed and no
+	 * change in any of the unsupported parameters
+	 */
+	if (key ||
+	    (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP))
+		return -EOPNOTSUPP;
+
+	if (!indir)
+		return 0;
+
 	for (i = 0; i < T_ETH_INDIRECTION_TABLE_SIZE; i++) {
 		/*
 		 * The same as in bnx2x_get_rxfh: we can't use a memcpy()

drivers/net/ethernet/broadcom/tg3.c

@@ -12561,22 +12561,38 @@ static u32 tg3_get_rxfh_indir_size(struct net_device *dev)
 	return size;
 }
 
-static int tg3_get_rxfh(struct net_device *dev, u32 *indir, u8 *key)
+static int tg3_get_rxfh(struct net_device *dev, u32 *indir, u8 *key, u8 *hfunc)
 {
 	struct tg3 *tp = netdev_priv(dev);
 	int i;
 
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+	if (!indir)
+		return 0;
+
 	for (i = 0; i < TG3_RSS_INDIR_TBL_SIZE; i++)
 		indir[i] = tp->rss_ind_tbl[i];
 
 	return 0;
 }
 
-static int tg3_set_rxfh(struct net_device *dev, const u32 *indir, const u8 *key)
+static int tg3_set_rxfh(struct net_device *dev, const u32 *indir, const u8 *key,
+			const u8 hfunc)
 {
 	struct tg3 *tp = netdev_priv(dev);
 	size_t i;
 
+	/* We require at least one supported parameter to be changed and no
+	 * change in any of the unsupported parameters
+	 */
+	if (key ||
+	    (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP))
+		return -EOPNOTSUPP;
+
+	if (!indir)
+		return 0;
+
 	for (i = 0; i < TG3_RSS_INDIR_TBL_SIZE; i++)
 		tp->rss_ind_tbl[i] = indir[i];
 

drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c

@@ -2923,21 +2923,35 @@ static u32 get_rss_table_size(struct net_device *dev)
 	return pi->rss_size;
 }
 
-static int get_rss_table(struct net_device *dev, u32 *p, u8 *key)
+static int get_rss_table(struct net_device *dev, u32 *p, u8 *key, u8 *hfunc)
 {
 	const struct port_info *pi = netdev_priv(dev);
 	unsigned int n = pi->rss_size;
 
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+	if (!p)
+		return 0;
 	while (n--)
 		p[n] = pi->rss[n];
 	return 0;
 }
 
-static int set_rss_table(struct net_device *dev, const u32 *p, const u8 *key)
+static int set_rss_table(struct net_device *dev, const u32 *p, const u8 *key,
+			 const u8 hfunc)
 {
 	unsigned int i;
 	struct port_info *pi = netdev_priv(dev);
 
+	/* We require at least one supported parameter to be changed and no
+	 * change in any of the unsupported parameters
+	 */
+	if (key ||
+	    (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP))
+		return -EOPNOTSUPP;
+	if (!p)
+		return 0;
+
 	for (i = 0; i < pi->rss_size; i++)
 		pi->rss[i] = p[i];
 	if (pi->adapter->flags & FULL_INIT_DONE)

drivers/net/ethernet/emulex/benet/be_ethtool.c

@@ -1171,7 +1171,8 @@ static u32 be_get_rxfh_key_size(struct net_device *netdev)
 	return RSS_HASH_KEY_LEN;
 }
 
-static int be_get_rxfh(struct net_device *netdev, u32 *indir, u8 *hkey)
+static int be_get_rxfh(struct net_device *netdev, u32 *indir, u8 *hkey,
+		       u8 *hfunc)
 {
 	struct be_adapter *adapter = netdev_priv(netdev);
 	int i;
@@ -1185,16 +1186,23 @@ static int be_get_rxfh(struct net_device *netdev, u32 *indir, u8 *hkey)
 	if (hkey)
 		memcpy(hkey, rss->rss_hkey, RSS_HASH_KEY_LEN);
 
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+
 	return 0;
 }
 
 static int be_set_rxfh(struct net_device *netdev, const u32 *indir,
-		       const u8 *hkey)
+		       const u8 *hkey, const u8 hfunc)
 {
 	int rc = 0, i, j;
 	struct be_adapter *adapter = netdev_priv(netdev);
 	u8 rsstable[RSS_INDIR_TABLE_LEN];
 
+	/* We do not allow change in unsupported parameters */
+	if (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP)
+		return -EOPNOTSUPP;
+
 	if (indir) {
 		struct be_rx_obj *rxo;
 

drivers/net/ethernet/intel/fm10k/fm10k_ethtool.c

@@ -916,11 +916,15 @@ static u32 fm10k_get_rssrk_size(struct net_device *netdev)
 	return FM10K_RSSRK_SIZE * FM10K_RSSRK_ENTRIES_PER_REG;
 }
 
-static int fm10k_get_rssh(struct net_device *netdev, u32 *indir, u8 *key)
+static int fm10k_get_rssh(struct net_device *netdev, u32 *indir, u8 *key,
+			  u8 *hfunc)
 {
 	struct fm10k_intfc *interface = netdev_priv(netdev);
 	int i, err;
 
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+
 	err = fm10k_get_reta(netdev, indir);
 	if (err || !key)
 		return err;
@@ -932,12 +936,16 @@ static int fm10k_get_rssh(struct net_device *netdev, u32 *indir, u8 *key)
 }
 
 static int fm10k_set_rssh(struct net_device *netdev, const u32 *indir,
-			  const u8 *key)
+			  const u8 *key, const u8 hfunc)
 {
 	struct fm10k_intfc *interface = netdev_priv(netdev);
 	struct fm10k_hw *hw = &interface->hw;
 	int i, err;
 
+	/* We do not allow change in unsupported parameters */
+	if (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP)
+		return -EOPNOTSUPP;
+
 	err = fm10k_set_reta(netdev, indir);
 	if (err || !key)
 		return err;

drivers/net/ethernet/intel/i40evf/i40evf_ethtool.c

@@ -627,13 +627,19 @@ static u32 i40evf_get_rxfh_indir_size(struct net_device *netdev)
  *
  * Reads the indirection table directly from the hardware. Always returns 0.
  **/
-static int i40evf_get_rxfh(struct net_device *netdev, u32 *indir, u8 *key)
+static int i40evf_get_rxfh(struct net_device *netdev, u32 *indir, u8 *key,
+			   u8 *hfunc)
 {
 	struct i40evf_adapter *adapter = netdev_priv(netdev);
 	struct i40e_hw *hw = &adapter->hw;
 	u32 hlut_val;
 	int i, j;
 
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+	if (!indir)
+		return 0;
+
 	for (i = 0, j = 0; i <= I40E_VFQF_HLUT_MAX_INDEX; i++) {
 		hlut_val = rd32(hw, I40E_VFQF_HLUT(i));
 		indir[j++] = hlut_val & 0xff;
@@ -654,13 +660,20 @@ static int i40evf_get_rxfh(struct net_device *netdev, u32 *indir, u8 *key)
  * returns 0 after programming the table.
  **/
 static int i40evf_set_rxfh(struct net_device *netdev, const u32 *indir,
-			   const u8 *key)
+			   const u8 *key, const u8 hfunc)
 {
 	struct i40evf_adapter *adapter = netdev_priv(netdev);
 	struct i40e_hw *hw = &adapter->hw;
 	u32 hlut_val;
 	int i, j;
 
+	/* We do not allow change in unsupported parameters */
+	if (key ||
+	    (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP))
+		return -EOPNOTSUPP;
+	if (!indir)
+		return 0;
+
 	for (i = 0, j = 0; i <= I40E_VFQF_HLUT_MAX_INDEX; i++) {
 		hlut_val = indir[j++];
 		hlut_val |= indir[j++] << 8;

drivers/net/ethernet/intel/igb/igb_ethtool.c

@@ -2842,11 +2842,16 @@ static u32 igb_get_rxfh_indir_size(struct net_device *netdev)
 	return IGB_RETA_SIZE;
 }
 
-static int igb_get_rxfh(struct net_device *netdev, u32 *indir, u8 *key)
+static int igb_get_rxfh(struct net_device *netdev, u32 *indir, u8 *key,
+			u8 *hfunc)
 {
 	struct igb_adapter *adapter = netdev_priv(netdev);
 	int i;
 
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+	if (!indir)
+		return 0;
 	for (i = 0; i < IGB_RETA_SIZE; i++)
 		indir[i] = adapter->rss_indir_tbl[i];
 
@@ -2889,13 +2894,20 @@ void igb_write_rss_indir_tbl(struct igb_adapter *adapter)
 }
 
 static int igb_set_rxfh(struct net_device *netdev, const u32 *indir,
-			const u8 *key)
+			const u8 *key, const u8 hfunc)
 {
 	struct igb_adapter *adapter = netdev_priv(netdev);
 	struct e1000_hw *hw = &adapter->hw;
 	int i;
 	u32 num_queues;
 
+	/* We do not allow change in unsupported parameters */
+	if (key ||
+	    (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP))
+		return -EOPNOTSUPP;
+	if (!indir)
+		return 0;
+
 	num_queues = adapter->rss_queues;
 
 	switch (hw->mac.type) {

drivers/net/ethernet/mellanox/mlx4/en_ethtool.c

@@ -978,7 +978,8 @@ static u32 mlx4_en_get_rxfh_key_size(struct net_device *netdev)
 	return MLX4_EN_RSS_KEY_SIZE;
 }
 
-static int mlx4_en_get_rxfh(struct net_device *dev, u32 *ring_index, u8 *key)
+static int mlx4_en_get_rxfh(struct net_device *dev, u32 *ring_index, u8 *key,
+			    u8 *hfunc)
 {
 	struct mlx4_en_priv *priv = netdev_priv(dev);
 	struct mlx4_en_rss_map *rss_map = &priv->rss_map;
@@ -990,16 +991,20 @@ static int mlx4_en_get_rxfh(struct net_device *dev, u32 *ring_index, u8 *key)
 	rss_rings = 1 << ilog2(rss_rings);
 
 	while (n--) {
+		if (!ring_index)
+			break;
 		ring_index[n] = rss_map->qps[n % rss_rings].qpn -
 			rss_map->base_qpn;
 	}
 	if (key)
 		memcpy(key, priv->rss_key, MLX4_EN_RSS_KEY_SIZE);
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
 	return err;
 }
 
 static int mlx4_en_set_rxfh(struct net_device *dev, const u32 *ring_index,
-			    const u8 *key)
+			    const u8 *key, const u8 hfunc)
 {
 	struct mlx4_en_priv *priv = netdev_priv(dev);
 	struct mlx4_en_dev *mdev = priv->mdev;
@@ -1008,6 +1013,10 @@ static int mlx4_en_set_rxfh(struct net_device *dev, const u32 *ring_index,
 	int i;
 	int rss_rings = 0;
 
+	/* We do not allow change in unsupported parameters */
+	if (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP)
+		return -EOPNOTSUPP;
+
 	/* Calculate RSS table size and make sure flows are spread evenly
 	 * between rings
 	 */

drivers/net/ethernet/sfc/ethtool.c

@@ -1086,19 +1086,29 @@ static u32 efx_ethtool_get_rxfh_indir_size(struct net_device *net_dev)
 		0 : ARRAY_SIZE(efx->rx_indir_table));
 }
 
-static int efx_ethtool_get_rxfh(struct net_device *net_dev, u32 *indir, u8 *key)
+static int efx_ethtool_get_rxfh(struct net_device *net_dev, u32 *indir, u8 *key,
+				u8 *hfunc)
 {
 	struct efx_nic *efx = netdev_priv(net_dev);
 
-	memcpy(indir, efx->rx_indir_table, sizeof(efx->rx_indir_table));
+	if (hfunc)
+		*hfunc = ETH_RSS_HASH_TOP;
+	if (indir)
+		memcpy(indir, efx->rx_indir_table, sizeof(efx->rx_indir_table));
 	return 0;
 }
 
-static int efx_ethtool_set_rxfh(struct net_device *net_dev,
-				const u32 *indir, const u8 *key)
+static int efx_ethtool_set_rxfh(struct net_device *net_dev, const u32 *indir,
+				const u8 *key, const u8 hfunc)
 {
 	struct efx_nic *efx = netdev_priv(net_dev);
 
+	/* We do not allow change in unsupported parameters */
+	if (key ||
+	    (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP))
+		return -EOPNOTSUPP;
+	if (!indir)
+		return 0;
 	memcpy(efx->rx_indir_table, indir, sizeof(efx->rx_indir_table));
 	efx->type->rx_push_rss_config(efx);
 	return 0;