Subject: [PATCH net-next v5 06/12] virtio_net: Create a FF group for ethtool steering

From: Daniel Jurgens <[email-masked]>
Date: Thu, 16 Oct 2025 00:00:49 -0500

All ethtool steering rules will go in one group, create it during
initialization.

Signed-off-by: Daniel Jurgens <[email-masked]>
Reviewed-by: Parav Pandit <[email-masked]>
Reviewed-by: Shahar Shitrit <[email-masked]>
---
v4: Documented UAPI
---
 drivers/net/virtio_net.c           | 29 +++++++++++++++++++++++++++++
 include/uapi/linux/virtio_net_ff.h | 15 +++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 39e1694b7bb6..4b00a130eb7a 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -284,6 +284,9 @@ static const struct virtnet_stat_desc virtnet_stats_tx_speed_desc_qstat[] = {
 	VIRTNET_STATS_DESC_TX_QSTAT(speed, ratelimit_packets, hw_drop_ratelimits),
 };
 
+#define VIRTNET_FF_ETHTOOL_GROUP_PRIORITY 1
+#define VIRTNET_FF_MAX_GROUPS 1
+
 struct virtnet_ff {
 	struct virtio_device *vdev;
 	bool ff_supported;
@@ -6791,6 +6794,7 @@ static void virtnet_ff_init(struct virtnet_ff *ff, struct virtio_device *vdev)
 	size_t ff_mask_size = sizeof(struct virtio_net_ff_cap_mask_data) +
 			      sizeof(struct virtio_net_ff_selector) *
 			      VIRTIO_NET_FF_MASK_TYPE_MAX;
+	struct virtio_net_resource_obj_ff_group ethtool_group = {};
 	struct virtio_admin_cmd_query_cap_id_result *cap_id_list;
 	struct virtio_net_ff_selector *sel;
 	int err;
@@ -6854,6 +6858,12 @@ static void virtnet_ff_init(struct virtnet_ff *ff, struct virtio_device *vdev)
 	if (err)
 		goto err_ff_action;
 
+	if (le32_to_cpu(ff->ff_caps->groups_limit) < VIRTNET_FF_MAX_GROUPS) {
+		err = -ENOSPC;
+		goto err_ff_action;
+	}
+	ff->ff_caps->groups_limit = cpu_to_le32(VIRTNET_FF_MAX_GROUPS);
+
 	err = virtio_admin_cap_set(vdev,
 				   VIRTIO_NET_FF_RESOURCE_CAP,
 				   ff->ff_caps,
@@ -6887,6 +6897,19 @@ static void virtnet_ff_init(struct virtnet_ff *ff, struct virtio_device *vdev)
 	if (err)
 		goto err_ff_action;
 
+	ethtool_group.group_priority = cpu_to_le16(VIRTNET_FF_ETHTOOL_GROUP_PRIORITY);
+
+	/* Use priority for the object ID. */
+	err = virtio_admin_obj_create(vdev,
+				      VIRTIO_NET_RESOURCE_OBJ_FF_GROUP,
+				      VIRTNET_FF_ETHTOOL_GROUP_PRIORITY,
+				      VIRTIO_ADMIN_GROUP_TYPE_SELF,
+				      0,
+				      &ethtool_group,
+				      sizeof(ethtool_group));
+	if (err)
+		goto err_ff_action;
+
 	ff->vdev = vdev;
 	ff->ff_supported = true;
 
@@ -6909,6 +6932,12 @@ static void virtnet_ff_cleanup(struct virtnet_ff *ff)
 	if (!ff->ff_supported)
 		return;
 
+	virtio_admin_obj_destroy(ff->vdev,
+				 VIRTIO_NET_RESOURCE_OBJ_FF_GROUP,
+				 VIRTNET_FF_ETHTOOL_GROUP_PRIORITY,
+				 VIRTIO_ADMIN_GROUP_TYPE_SELF,
+				 0);
+
 	kfree(ff->ff_actions);
 	kfree(ff->ff_mask);
 	kfree(ff->ff_caps);
diff --git a/include/uapi/linux/virtio_net_ff.h b/include/uapi/linux/virtio_net_ff.h
index 1a4738889403..eebaaf8f9468 100644
--- a/include/uapi/linux/virtio_net_ff.h
+++ b/include/uapi/linux/virtio_net_ff.h
@@ -12,6 +12,8 @@
 #define VIRTIO_NET_FF_SELECTOR_CAP 0x801
 #define VIRTIO_NET_FF_ACTION_CAP 0x802
 
+#define VIRTIO_NET_RESOURCE_OBJ_FF_GROUP 0x0200
+
 /**
  * struct virtio_net_ff_cap_data - Flow filter resource capability limits
  * @groups_limit: maximum number of flow filter groups supported by the device
@@ -88,4 +90,17 @@ struct virtio_net_ff_actions {
 	__u8 reserved[7];
 	__u8 actions[];
 };
+
+/**
+ * struct virtio_net_resource_obj_ff_group - Flow filter group object
+ * @group_priority: priority of the group used to order evaluation
+ *
+ * This structure is the payload for the VIRTIO_NET_RESOURCE_OBJ_FF_GROUP
+ * administrative object. Devices use @group_priority to order flow filter
+ * groups. Multi-byte fields are little-endian.
+ */
+struct virtio_net_resource_obj_ff_group {
+	__le16 group_priority;
+};
+
 #endif
-- 
2.50.1