nfp: allow control message reception on data queues

Port id 0xffffffff is reserved for control messages.  Allow reception
of messages with this id on data queues.  Hand off a raw buffer to
the higher layer code, without allocating SKB for max efficiency.
The RX handle can't modify or keep the buffer, after it returns
buffer is handed back over to the NIC RX free buffer list.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

drivers/net/ethernet/netronome/nfp/nfp_app.c

@@ -172,6 +172,8 @@ struct nfp_app *nfp_app_alloc(struct nfp_pf *pf, enum nfp_app_id id)
 
 	if (WARN_ON(!apps[id]->name || !apps[id]->vnic_alloc))
 		return ERR_PTR(-EINVAL);
+	if (WARN_ON(!apps[id]->ctrl_msg_rx && apps[id]->ctrl_msg_rx_raw))
+		return ERR_PTR(-EINVAL);
 
 	app = kzalloc(sizeof(*app), GFP_KERNEL);
 	if (!app)

drivers/net/ethernet/netronome/nfp/nfp_app.h

@@ -98,6 +98,7 @@ extern const struct nfp_app_type app_abm;
  * @start:	start application logic
  * @stop:	stop application logic
  * @ctrl_msg_rx:    control message handler
+ * @ctrl_msg_rx_raw:	handler for control messages from data queues
  * @setup_tc:	setup TC ndo
  * @bpf:	BPF ndo offload-related calls
  * @xdp_offload:    offload an XDP program
@@ -150,6 +151,8 @@ struct nfp_app_type {
 	void (*stop)(struct nfp_app *app);
 
 	void (*ctrl_msg_rx)(struct nfp_app *app, struct sk_buff *skb);
+	void (*ctrl_msg_rx_raw)(struct nfp_app *app, const void *data,
+				unsigned int len);
 
 	int (*setup_tc)(struct nfp_app *app, struct net_device *netdev,
 			enum tc_setup_type type, void *type_data);
@@ -318,6 +321,11 @@ static inline bool nfp_app_ctrl_has_meta(struct nfp_app *app)
 	return app->type->ctrl_has_meta;
 }
 
+static inline bool nfp_app_ctrl_uses_data_vnics(struct nfp_app *app)
+{
+	return app && app->type->ctrl_msg_rx_raw;
+}
+
 static inline const char *nfp_app_extra_cap(struct nfp_app *app,
 					    struct nfp_net *nn)
 {
@@ -381,6 +389,15 @@ static inline void nfp_app_ctrl_rx(struct nfp_app *app, struct sk_buff *skb)
 	app->type->ctrl_msg_rx(app, skb);
 }
 
+static inline void
+nfp_app_ctrl_rx_raw(struct nfp_app *app, const void *data, unsigned int len)
+{
+	trace_devlink_hwmsg(priv_to_devlink(app->pf), true, 0, data, len);
+
+	if (app && app->type->ctrl_msg_rx_raw)
+		app->type->ctrl_msg_rx_raw(app, data, len);
+}
+
 static inline int nfp_app_eswitch_mode_get(struct nfp_app *app, u16 *mode)
 {
 	if (!app->type->eswitch_mode_get)

drivers/net/ethernet/netronome/nfp/nfp_net_common.c

@@ -1759,6 +1759,14 @@ static int nfp_net_rx(struct nfp_net_rx_ring *rx_ring, int budget)
 
 		if (likely(!meta.portid)) {
 			netdev = dp->netdev;
+		} else if (meta.portid == NFP_META_PORT_ID_CTRL) {
+			struct nfp_net *nn = netdev_priv(dp->netdev);
+
+			nfp_app_ctrl_rx_raw(nn->app, rxbuf->frag + pkt_off,
+					    pkt_len);
+			nfp_net_rx_give_one(dp, rx_ring, rxbuf->frag,
+					    rxbuf->dma_addr);
+			continue;
 		} else {
 			struct nfp_net *nn;
 
@@ -3857,6 +3865,9 @@ int nfp_net_init(struct nfp_net *nn)
 		nn->dp.mtu = NFP_NET_DEFAULT_MTU;
 	nn->dp.fl_bufsz = nfp_net_calc_fl_bufsz(&nn->dp);
 
+	if (nfp_app_ctrl_uses_data_vnics(nn->app))
+		nn->dp.ctrl |= nn->cap & NFP_NET_CFG_CTRL_CMSG_DATA;
+
 	if (nn->cap & NFP_NET_CFG_CTRL_RSS_ANY) {
 		nfp_net_rss_init(nn);
 		nn->dp.ctrl |= nn->cap & NFP_NET_CFG_CTRL_RSS2 ?:

drivers/net/ethernet/netronome/nfp/nfp_net_ctrl.h

@@ -127,6 +127,7 @@
 #define   NFP_NET_CFG_CTRL_GATHER	  (0x1 <<  9) /* Gather DMA */
 #define   NFP_NET_CFG_CTRL_LSO		  (0x1 << 10) /* LSO/TSO (version 1) */
 #define   NFP_NET_CFG_CTRL_CTAG_FILTER	  (0x1 << 11) /* VLAN CTAG filtering */
+#define   NFP_NET_CFG_CTRL_CMSG_DATA	  (0x1 << 12) /* RX cmsgs on data Qs */
 #define   NFP_NET_CFG_CTRL_RINGCFG	  (0x1 << 16) /* Ring runtime changes */
 #define   NFP_NET_CFG_CTRL_RSS		  (0x1 << 17) /* RSS (version 1) */
 #define   NFP_NET_CFG_CTRL_IRQMOD	  (0x1 << 18) /* Interrupt moderation */