Merge branch 'ethtool-rss-support-rss_set-via-netlink'

Jakub Kicinski says:

====================
ethtool: rss: support RSS_SET via Netlink

Support configuring RSS settings via Netlink.
Creating and removing contexts remains for the following series.

v2: https://lore.kernel.org/[email protected]
v1: https://lore.kernel.org/[email protected]
====================

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: kuba-moo

Documentation/netlink/specs/ethtool.yaml

@@ -158,6 +158,26 @@ definitions:
       -
         name: pse-event-sw-pw-control-error
         doc: PSE faced an error managing the power control from software
+  -
+    name: input-xfrm
+    doc: RSS hash function transformations.
+    type: flags
+    enum-name:
+    name-prefix: rxh-xfrm-
+    header: linux/ethtool.h
+    entries:
+      -
+        name: sym-xor
+        doc: >-
+          XOR the corresponding source and destination fields of each specified
+          protocol. Both copies of the XOR'ed fields are fed into the RSS and
+          RXHASH calculation. Note that this XORing reduces the input set
+          entropy and could be exploited to reduce the RSS queue spread.
+      -
+        name: sym-or-xor
+        doc: >-
+          Similar to SYM_XOR, except that one copy of the XOR'ed fields is
+          replaced by an OR of the same fields.
   -
     name: rxfh-fields
     name-prefix: rxh-
@@ -1621,6 +1641,7 @@ attribute-sets:
       -
         name: input-xfrm
         type: u32
+        enum: input-xfrm
       -
         name: start-context
         type: u32
@@ -2643,6 +2664,22 @@ operations:
         attributes:
           - header
           - events
+    -
+      name: rss-set
+      doc: Set RSS params.
+
+      attribute-set: rss
+
+      do:
+        request:
+          attributes:
+            - header
+            - context
+            - hfunc
+            - indir
+            - hkey
+            - input-xfrm
+            - flow-hash
     -
       name: rss-ntf
       doc: |

Documentation/networking/ethtool-netlink.rst

@@ -239,6 +239,7 @@ Userspace to kernel:
   ``ETHTOOL_MSG_PHY_GET``               get Ethernet PHY information
   ``ETHTOOL_MSG_TSCONFIG_GET``          get hw timestamping configuration
   ``ETHTOOL_MSG_TSCONFIG_SET``          set hw timestamping configuration
+  ``ETHTOOL_MSG_RSS_SET``               set RSS settings
   ===================================== =================================
 
 Kernel to userspace:
@@ -292,6 +293,7 @@ Kernel to userspace:
   ``ETHTOOL_MSG_TSCONFIG_GET_REPLY``       hw timestamping configuration
   ``ETHTOOL_MSG_TSCONFIG_SET_REPLY``       new hw timestamping configuration
   ``ETHTOOL_MSG_PSE_NTF``                  PSE events notification
+  ``ETHTOOL_MSG_RSS_NTF``                  RSS settings notification
   ======================================== =================================
 
 ``GET`` requests are sent by userspace applications to retrieve device
@@ -1989,6 +1991,29 @@ hfunc. Current supported options are symmetric-xor and symmetric-or-xor.
 ETHTOOL_A_RSS_FLOW_HASH carries per-flow type bitmask of which header
 fields are included in the hash calculation.
 
+RSS_SET
+=======
+
+Request contents:
+
+=====================================  ======  ==============================
+  ``ETHTOOL_A_RSS_HEADER``             nested  request header
+  ``ETHTOOL_A_RSS_CONTEXT``            u32     context number
+  ``ETHTOOL_A_RSS_HFUNC``              u32     RSS hash func
+  ``ETHTOOL_A_RSS_INDIR``              binary  Indir table bytes
+  ``ETHTOOL_A_RSS_HKEY``               binary  Hash key bytes
+  ``ETHTOOL_A_RSS_INPUT_XFRM``         u32     RSS input data transformation
+  ``ETHTOOL_A_RSS_FLOW_HASH``          nested  Header fields included in hash
+=====================================  ======  ==============================
+
+``ETHTOOL_A_RSS_INDIR`` is the minimal RSS table the user expects. Kernel and
+the device driver may replicate the table if its smaller than smallest table
+size supported by the device. For example if user requests ``[0, 1]`` but the
+device needs at least 8 entries - the real table in use will end up being
+``[0, 1, 0, 1, 0, 1, 0, 1]``. Most devices require the table size to be power
+of 2, so tables which size is not a power of 2 will likely be rejected.
+Using table of size 0 will reset the indirection table to the default.
+
 PLCA_GET_CFG
 ============
 
@@ -2440,7 +2465,7 @@ are netlink only.
   ``ETHTOOL_GPFLAGS``                 ``ETHTOOL_MSG_PRIVFLAGS_GET``
   ``ETHTOOL_SPFLAGS``                 ``ETHTOOL_MSG_PRIVFLAGS_SET``
   ``ETHTOOL_GRXFH``                   ``ETHTOOL_MSG_RSS_GET``
-  ``ETHTOOL_SRXFH``                   n/a
+  ``ETHTOOL_SRXFH``                   ``ETHTOOL_MSG_RSS_SET``
   ``ETHTOOL_GGRO``                    ``ETHTOOL_MSG_FEATURES_GET``
   ``ETHTOOL_SGRO``                    ``ETHTOOL_MSG_FEATURES_SET``
   ``ETHTOOL_GRXRINGS``                n/a
@@ -2455,7 +2480,7 @@ are netlink only.
   ``ETHTOOL_GRXNTUPLE``               n/a
   ``ETHTOOL_GSSET_INFO``              ``ETHTOOL_MSG_STRSET_GET``
   ``ETHTOOL_GRXFHINDIR``              ``ETHTOOL_MSG_RSS_GET``
-  ``ETHTOOL_SRXFHINDIR``              n/a
+  ``ETHTOOL_SRXFHINDIR``              ``ETHTOOL_MSG_RSS_SET``
   ``ETHTOOL_GFEATURES``               ``ETHTOOL_MSG_FEATURES_GET``
   ``ETHTOOL_SFEATURES``               ``ETHTOOL_MSG_FEATURES_SET``
   ``ETHTOOL_GCHANNELS``               ``ETHTOOL_MSG_CHANNELS_GET``

include/uapi/linux/ethtool_netlink_generated.h

@@ -840,6 +840,7 @@ enum {
 	ETHTOOL_MSG_PHY_GET,
 	ETHTOOL_MSG_TSCONFIG_GET,
 	ETHTOOL_MSG_TSCONFIG_SET,
+	ETHTOOL_MSG_RSS_SET,
 
 	__ETHTOOL_MSG_USER_CNT,
 	ETHTOOL_MSG_USER_MAX = (__ETHTOOL_MSG_USER_CNT - 1)

net/ethtool/common.c

@@ -806,6 +806,21 @@ int ethtool_check_rss_ctx_busy(struct net_device *dev, u32 rss_context)
 	return rc;
 }
 
+/* Check if fields configured for flow hash are symmetric - if src is included
+ * so is dst and vice versa.
+ */
+int ethtool_rxfh_config_is_sym(u64 rxfh)
+{
+	bool sym;
+
+	sym = rxfh == (rxfh & (RXH_IP_SRC | RXH_IP_DST |
+			       RXH_L4_B_0_1 | RXH_L4_B_2_3));
+	sym &= !!(rxfh & RXH_IP_SRC)   == !!(rxfh & RXH_IP_DST);
+	sym &= !!(rxfh & RXH_L4_B_0_1) == !!(rxfh & RXH_L4_B_2_3);
+
+	return sym;
+}
+
 int ethtool_check_ops(const struct ethtool_ops *ops)
 {
 	if (WARN_ON(ops->set_coalesce && !ops->supported_coalesce_params))

net/ethtool/common.h

@@ -44,6 +44,7 @@ int ethtool_check_max_channel(struct net_device *dev,
 			      struct ethtool_channels channels,
 			      struct genl_info *info);
 int ethtool_check_rss_ctx_busy(struct net_device *dev, u32 rss_context);
+int ethtool_rxfh_config_is_sym(u64 rxfh);
 
 void ethtool_ringparam_get_cfg(struct net_device *dev,
 			       struct ethtool_ringparam *param,

net/ethtool/ioctl.c

@@ -1027,9 +1027,7 @@ static int ethtool_check_xfrm_rxfh(u32 input_xfrm, u64 rxfh)
 	 */
 	if ((input_xfrm != RXH_XFRM_NO_CHANGE &&
 	     input_xfrm & (RXH_XFRM_SYM_XOR | RXH_XFRM_SYM_OR_XOR)) &&
-	    ((rxfh & ~(RXH_IP_SRC | RXH_IP_DST | RXH_L4_B_0_1 | RXH_L4_B_2_3)) ||
-	     (!!(rxfh & RXH_IP_SRC) ^ !!(rxfh & RXH_IP_DST)) ||
-	     (!!(rxfh & RXH_L4_B_0_1) ^ !!(rxfh & RXH_L4_B_2_3))))
+	    !ethtool_rxfh_config_is_sym(rxfh))
 		return -EINVAL;
 
 	return 0;

net/ethtool/netlink.c

@@ -405,6 +405,7 @@ ethnl_default_requests[__ETHTOOL_MSG_USER_CNT] = {
 	[ETHTOOL_MSG_PSE_GET]		= &ethnl_pse_request_ops,
 	[ETHTOOL_MSG_PSE_SET]		= &ethnl_pse_request_ops,
 	[ETHTOOL_MSG_RSS_GET]		= &ethnl_rss_request_ops,
+	[ETHTOOL_MSG_RSS_SET]		= &ethnl_rss_request_ops,
 	[ETHTOOL_MSG_PLCA_GET_CFG]	= &ethnl_plca_cfg_request_ops,
 	[ETHTOOL_MSG_PLCA_SET_CFG]	= &ethnl_plca_cfg_request_ops,
 	[ETHTOOL_MSG_PLCA_GET_STATUS]	= &ethnl_plca_status_request_ops,
@@ -1504,6 +1505,13 @@ static const struct genl_ops ethtool_genl_ops[] = {
 		.policy = ethnl_tsconfig_set_policy,
 		.maxattr = ARRAY_SIZE(ethnl_tsconfig_set_policy) - 1,
 	},
+	{
+		.cmd	= ETHTOOL_MSG_RSS_SET,
+		.flags	= GENL_UNS_ADMIN_PERM,
+		.doit	= ethnl_default_set_doit,
+		.policy = ethnl_rss_set_policy,
+		.maxattr = ARRAY_SIZE(ethnl_rss_set_policy) - 1,
+	},
 };
 
 static const struct genl_multicast_group ethtool_nl_mcgrps[] = {

net/ethtool/netlink.h

@@ -484,6 +484,7 @@ extern const struct nla_policy ethnl_module_set_policy[ETHTOOL_A_MODULE_POWER_MO
 extern const struct nla_policy ethnl_pse_get_policy[ETHTOOL_A_PSE_HEADER + 1];
 extern const struct nla_policy ethnl_pse_set_policy[ETHTOOL_A_PSE_MAX + 1];
 extern const struct nla_policy ethnl_rss_get_policy[ETHTOOL_A_RSS_START_CONTEXT + 1];
+extern const struct nla_policy ethnl_rss_set_policy[ETHTOOL_A_RSS_FLOW_HASH + 1];
 extern const struct nla_policy ethnl_plca_get_cfg_policy[ETHTOOL_A_PLCA_HEADER + 1];
 extern const struct nla_policy ethnl_plca_set_cfg_policy[ETHTOOL_A_PLCA_MAX + 1];
 extern const struct nla_policy ethnl_plca_get_status_policy[ETHTOOL_A_PLCA_HEADER + 1];