ice: Add slow path offload stats on port representor in switchdev

Implement callbacks to check for stats and fetch port representor stats.
Stats are taken from RX/TX ring corresponding to port representor and show
the number of bytes/packets that were not offloaded.

To see slow path stats run:
ifstat -x cpu_hits -a
Signed-off-by: NMarcin Szycik <marcin.szycik@linux.intel.com>
Tested-by: NSandeep Penigalapati <sandeep.penigalapati@intel.com>
Signed-off-by: NTony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/ice/ice.h

@@ -833,6 +833,9 @@ u16 ice_get_avail_rxq_count(struct ice_pf *pf);
 int ice_vsi_recfg_qs(struct ice_vsi *vsi, int new_rx, int new_tx);
 void ice_update_vsi_stats(struct ice_vsi *vsi);
 void ice_update_pf_stats(struct ice_pf *pf);
+void
+ice_fetch_u64_stats_per_ring(struct u64_stats_sync *syncp,
+			     struct ice_q_stats stats, u64 *pkts, u64 *bytes);
 int ice_up(struct ice_vsi *vsi);
 int ice_down(struct ice_vsi *vsi);
 int ice_vsi_cfg(struct ice_vsi *vsi);

drivers/net/ethernet/intel/ice/ice_main.c

@@ -6113,9 +6113,9 @@ int ice_up(struct ice_vsi *vsi)
  * This function fetches stats from the ring considering the atomic operations
  * that needs to be performed to read u64 values in 32 bit machine.
  */
-static void
-ice_fetch_u64_stats_per_ring(struct u64_stats_sync *syncp, struct ice_q_stats stats,
-			     u64 *pkts, u64 *bytes)
+void
+ice_fetch_u64_stats_per_ring(struct u64_stats_sync *syncp,
+			     struct ice_q_stats stats, u64 *pkts, u64 *bytes)
 {
 	unsigned int start;
 

drivers/net/ethernet/intel/ice/ice_repr.c

@@ -142,6 +142,59 @@ ice_repr_get_devlink_port(struct net_device *netdev)
 	return &repr->vf->devlink_port;
 }
 
+/**
+ * ice_repr_sp_stats64 - get slow path stats for port representor
+ * @dev: network interface device structure
+ * @stats: netlink stats structure
+ *
+ * RX/TX stats are being swapped here to be consistent with VF stats. In slow
+ * path, port representor receives data when the corresponding VF is sending it
+ * (and vice versa), TX and RX bytes/packets are effectively swapped on port
+ * representor.
+ */
+static int
+ice_repr_sp_stats64(const struct net_device *dev,
+		    struct rtnl_link_stats64 *stats)
+{
+	struct ice_netdev_priv *np = netdev_priv(dev);
+	int vf_id = np->repr->vf->vf_id;
+	struct ice_tx_ring *tx_ring;
+	struct ice_rx_ring *rx_ring;
+	u64 pkts, bytes;
+
+	tx_ring = np->vsi->tx_rings[vf_id];
+	ice_fetch_u64_stats_per_ring(&tx_ring->syncp, tx_ring->stats,
+				     &pkts, &bytes);
+	stats->rx_packets = pkts;
+	stats->rx_bytes = bytes;
+
+	rx_ring = np->vsi->rx_rings[vf_id];
+	ice_fetch_u64_stats_per_ring(&rx_ring->syncp, rx_ring->stats,
+				     &pkts, &bytes);
+	stats->tx_packets = pkts;
+	stats->tx_bytes = bytes;
+	stats->tx_dropped = rx_ring->rx_stats.alloc_page_failed +
+			    rx_ring->rx_stats.alloc_buf_failed;
+
+	return 0;
+}
+
+static bool
+ice_repr_ndo_has_offload_stats(const struct net_device *dev, int attr_id)
+{
+	return attr_id == IFLA_OFFLOAD_XSTATS_CPU_HIT;
+}
+
+static int
+ice_repr_ndo_get_offload_stats(int attr_id, const struct net_device *dev,
+			       void *sp)
+{
+	if (attr_id == IFLA_OFFLOAD_XSTATS_CPU_HIT)
+		return ice_repr_sp_stats64(dev, (struct rtnl_link_stats64 *)sp);
+
+	return -EINVAL;
+}
+
 static int
 ice_repr_setup_tc_cls_flower(struct ice_repr *repr,
 			     struct flow_cls_offload *flower)
@@ -199,6 +252,8 @@ static const struct net_device_ops ice_repr_netdev_ops = {
 	.ndo_start_xmit = ice_eswitch_port_start_xmit,
 	.ndo_get_devlink_port = ice_repr_get_devlink_port,
 	.ndo_setup_tc = ice_repr_setup_tc,
+	.ndo_has_offload_stats = ice_repr_ndo_has_offload_stats,
+	.ndo_get_offload_stats = ice_repr_ndo_get_offload_stats,
 };
 
 /**