ethtool: rss: support setting input-xfrm via Netlink

Support configuring symmetric hashing via Netlink.
We have the flow field config prepared as part of SET handling,
so scan it for conflicts instead of querying the driver again.

Reviewed-by: Gal Pressman <gal@nvidia.com>
Link: https://patch.msgid.link/20250716000331.1378807-10-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 52 insertions, 2 deletions

diff --git a/net/ethtool/rss.c b/net/ethtool/rss.c
index 55260830639f..79de013da288 100644
--- a/net/ethtool/rss.c
+++ b/net/ethtool/rss.c
@@ -478,6 +478,8 @@ const struct nla_policy ethnl_rss_set_policy[ETHTOOL_A_RSS_START_CONTEXT + 1] =
 	[ETHTOOL_A_RSS_HFUNC] = NLA_POLICY_MIN(NLA_U32, 1),
 	[ETHTOOL_A_RSS_INDIR] = { .type = NLA_BINARY, },
 	[ETHTOOL_A_RSS_HKEY] = NLA_POLICY_MIN(NLA_BINARY, 1),
+	[ETHTOOL_A_RSS_INPUT_XFRM] =
+		NLA_POLICY_MAX(NLA_U32, RXH_XFRM_SYM_OR_XOR),
 };
 
 static int
@@ -487,6 +489,7 @@ ethnl_rss_set_validate(struct ethnl_req_info *req_info, struct genl_info *info)
 	struct rss_req_info *request = RSS_REQINFO(req_info);
 	struct nlattr **tb = info->attrs;
 	struct nlattr *bad_attr = NULL;
+	u32 input_xfrm;
 
 	if (request->rss_context && !ops->create_rxfh_context)
 		bad_attr = bad_attr ?: tb[ETHTOOL_A_RSS_CONTEXT];
@@ -494,8 +497,13 @@ ethnl_rss_set_validate(struct ethnl_req_info *req_info, struct genl_info *info)
 	if (request->rss_context && !ops->rxfh_per_ctx_key) {
 		bad_attr = bad_attr ?: tb[ETHTOOL_A_RSS_HFUNC];
 		bad_attr = bad_attr ?: tb[ETHTOOL_A_RSS_HKEY];
+		bad_attr = bad_attr ?: tb[ETHTOOL_A_RSS_INPUT_XFRM];
 	}
 
+	input_xfrm = nla_get_u32_default(tb[ETHTOOL_A_RSS_INPUT_XFRM], 0);
+	if (input_xfrm & ~ops->supported_input_xfrm)
+		bad_attr = bad_attr ?: tb[ETHTOOL_A_RSS_INPUT_XFRM];
+
 	if (bad_attr) {
 		NL_SET_BAD_ATTR(info->extack, bad_attr);
 		return -EOPNOTSUPP;
@@ -609,6 +617,33 @@ rss_set_prep_hkey(struct net_device *dev, struct genl_info *info,
 	return 0;
 }
 
+static int
+rss_check_rxfh_fields_sym(struct net_device *dev, struct genl_info *info,
+			  struct rss_reply_data *data, bool xfrm_sym)
+{
+	struct nlattr **tb = info->attrs;
+	int i;
+
+	if (!xfrm_sym)
+		return 0;
+	if (!data->has_flow_hash) {
+		NL_SET_ERR_MSG_ATTR(info->extack, tb[ETHTOOL_A_RSS_INPUT_XFRM],
+				    "hash field config not reported");
+		return -EINVAL;
+	}
+
+	for (i = 1; i < __ETHTOOL_A_FLOW_CNT; i++)
+		if (data->flow_hash[i] >= 0 &&
+		    !ethtool_rxfh_config_is_sym(data->flow_hash[i])) {
+			NL_SET_ERR_MSG_ATTR(info->extack,
+					    tb[ETHTOOL_A_RSS_INPUT_XFRM],
+					    "hash field config is not symmetric");
+			return -EINVAL;
+		}
+
+	return 0;
+}
+
 static void
 rss_set_ctx_update(struct ethtool_rxfh_context *ctx, struct nlattr **tb,
 		   struct rss_reply_data *data, struct ethtool_rxfh_param *rxfh)
@@ -627,16 +662,18 @@ rss_set_ctx_update(struct ethtool_rxfh_context *ctx, struct nlattr **tb,
 	}
 	if (rxfh->hfunc != ETH_RSS_HASH_NO_CHANGE)
 		ctx->hfunc = rxfh->hfunc;
+	if (rxfh->input_xfrm != RXH_XFRM_NO_CHANGE)
+		ctx->input_xfrm = rxfh->input_xfrm;
 }
 
 static int
 ethnl_rss_set(struct ethnl_req_info *req_info, struct genl_info *info)
 {
+	bool indir_reset = false, indir_mod, xfrm_sym = false;
 	struct rss_req_info *request = RSS_REQINFO(req_info);
 	struct ethtool_rxfh_context *ctx = NULL;
 	struct net_device *dev = req_info->dev;
 	struct ethtool_rxfh_param rxfh = {};
-	bool indir_reset = false, indir_mod;
 	struct nlattr **tb = info->attrs;
 	struct rss_reply_data data = {};
 	const struct ethtool_ops *ops;
@@ -666,7 +703,20 @@ ethnl_rss_set(struct ethnl_req_info *req_info, struct genl_info *info)
 	if (ret)
 		goto exit_free_indir;
 
-	rxfh.input_xfrm = RXH_XFRM_NO_CHANGE;
+	rxfh.input_xfrm = data.input_xfrm;
+	ethnl_update_u8(&rxfh.input_xfrm, tb[ETHTOOL_A_RSS_INPUT_XFRM], &mod);
+	/* For drivers which don't support input_xfrm it will be set to 0xff
+	 * in the RSS context info. In all other case input_xfrm != 0 means
+	 * symmetric hashing is requested.
+	 */
+	if (!request->rss_context || ops->rxfh_per_ctx_key)
+		xfrm_sym = !!rxfh.input_xfrm;
+	if (rxfh.input_xfrm == data.input_xfrm)
+		rxfh.input_xfrm = RXH_XFRM_NO_CHANGE;
+
+	ret = rss_check_rxfh_fields_sym(dev, info, &data, xfrm_sym);
+	if (ret)
+		goto exit_clean_data;
 
 	mutex_lock(&dev->ethtool->rss_lock);
 	if (request->rss_context) {