Subject: [PATCH net-next v18 12/12] virtio_net: Add get ethtool flow rules ops

From: Daniel Jurgens <[email-masked]>
Date: Tue, 3 Feb 2026 16:28:59 -0600

- Get total number of rules. There's no user interface for this. It is
  used to allocate an appropriately sized buffer for getting all the
  rules.

- Get specific rule
$ ethtool -u ens9 rule 0
	Filter: 0
		Rule Type: UDP over IPv4
		Src IP addr: 0.0.0.0 mask: 255.255.255.255
		Dest IP addr: 192.168.5.2 mask: 0.0.0.0
		TOS: 0x0 mask: 0xff
		Src port: 0 mask: 0xffff
		Dest port: 4321 mask: 0x0
		Action: Direct to queue 16

- Get all rules:
$ ethtool -u ens9
31 RX rings available
Total 2 rules

Filter: 0
        Rule Type: UDP over IPv4
        Src IP addr: 0.0.0.0 mask: 255.255.255.255
        Dest IP addr: 192.168.5.2 mask: 0.0.0.0
...

Filter: 1
        Flow Type: Raw Ethernet
        Src MAC addr: 00:00:00:00:00:00 mask: FF:FF:FF:FF:FF:FF
        Dest MAC addr: 08:11:22:33:44:54 mask: 00:00:00:00:00:00

Signed-off-by: Daniel Jurgens <[email-masked]>
Reviewed-by: Parav Pandit <[email-masked]>
Reviewed-by: Shahar Shitrit <[email-masked]>
Reviewed-by: Xuan Zhuo <[email-masked]>
---
v4: Answered questions about rules_limit overflow with no changes.

v12:
  - Use and set rule_cnt in virtnet_ethtool_get_all_flows. MST
  - Leave rc uninitiazed at the top of virtnet_get_rxnfc. MST
---
---
 drivers/net/virtio_net.c | 82 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 155f0ceab006..24e586ff6b14 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -313,6 +313,13 @@ static int virtnet_ethtool_flow_insert(struct virtnet_ff *ff,
 				       struct ethtool_rx_flow_spec *fs,
 				       u16 curr_queue_pairs);
 static int virtnet_ethtool_flow_remove(struct virtnet_ff *ff, int location);
+static int virtnet_ethtool_get_flow_count(struct virtnet_ff *ff,
+					  struct ethtool_rxnfc *info);
+static int virtnet_ethtool_get_flow(struct virtnet_ff *ff,
+				    struct ethtool_rxnfc *info);
+static int
+virtnet_ethtool_get_all_flows(struct virtnet_ff *ff,
+			      struct ethtool_rxnfc *info, u32 *rule_locs);
 
 #define VIRTNET_Q_TYPE_RX 0
 #define VIRTNET_Q_TYPE_TX 1
@@ -5596,6 +5603,28 @@ static u32 virtnet_get_rx_ring_count(struct net_device *dev)
 	return vi->curr_queue_pairs;
 }
 
+static int virtnet_get_rxnfc(struct net_device *dev, struct ethtool_rxnfc *info, u32 *rule_locs)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	int rc;
+
+	switch (info->cmd) {
+	case ETHTOOL_GRXCLSRLCNT:
+		rc = virtnet_ethtool_get_flow_count(&vi->ff, info);
+		break;
+	case ETHTOOL_GRXCLSRULE:
+		rc = virtnet_ethtool_get_flow(&vi->ff, info);
+		break;
+	case ETHTOOL_GRXCLSRLALL:
+		rc = virtnet_ethtool_get_all_flows(&vi->ff, info, rule_locs);
+		break;
+	default:
+		rc = -EOPNOTSUPP;
+	}
+
+	return rc;
+}
+
 static int virtnet_set_rxnfc(struct net_device *dev, struct ethtool_rxnfc *info)
 {
 	struct virtnet_info *vi = netdev_priv(dev);
@@ -5637,6 +5666,7 @@ static const struct ethtool_ops virtnet_ethtool_ops = {
 	.get_rxfh_fields = virtnet_get_hashflow,
 	.set_rxfh_fields = virtnet_set_hashflow,
 	.get_rx_ring_count = virtnet_get_rx_ring_count,
+	.get_rxnfc = virtnet_get_rxnfc,
 	.set_rxnfc = virtnet_set_rxnfc,
 };
 
@@ -6568,6 +6598,58 @@ static int virtnet_ethtool_flow_remove(struct virtnet_ff *ff, int location)
 	return err;
 }
 
+static int virtnet_ethtool_get_flow_count(struct virtnet_ff *ff,
+					  struct ethtool_rxnfc *info)
+{
+	if (!ff->ff_supported)
+		return -EOPNOTSUPP;
+
+	info->rule_cnt = ff->ethtool.num_rules;
+	info->data = le32_to_cpu(ff->ff_caps->rules_limit) | RX_CLS_LOC_SPECIAL;
+
+	return 0;
+}
+
+static int virtnet_ethtool_get_flow(struct virtnet_ff *ff,
+				    struct ethtool_rxnfc *info)
+{
+	struct virtnet_ethtool_rule *eth_rule;
+
+	if (!ff->ff_supported)
+		return -EOPNOTSUPP;
+
+	eth_rule = xa_load(&ff->ethtool.rules, info->fs.location);
+	if (!eth_rule)
+		return -ENOENT;
+
+	info->fs = eth_rule->flow_spec;
+
+	return 0;
+}
+
+static int
+virtnet_ethtool_get_all_flows(struct virtnet_ff *ff,
+			      struct ethtool_rxnfc *info, u32 *rule_locs)
+{
+	struct virtnet_ethtool_rule *eth_rule;
+	unsigned long i = 0;
+	int idx = 0;
+
+	if (!ff->ff_supported)
+		return -EOPNOTSUPP;
+
+	xa_for_each(&ff->ethtool.rules, i, eth_rule) {
+		if (idx == info->rule_cnt)
+			return -EMSGSIZE;
+		rule_locs[idx++] = i;
+	}
+
+	info->data = le32_to_cpu(ff->ff_caps->rules_limit);
+	info->rule_cnt = idx;
+
+	return 0;
+}
+
 static size_t get_mask_size(u16 type)
 {
 	switch (type) {
-- 
2.50.1