ixgbe: add support for XDP_TX action

A couple design choices were made here. First I use a new ring
pointer structure xdp_ring[] in the adapter struct instead of
pushing the newly allocated XDP TX rings into the tx_ring[]
structure. This means we have to duplicate loops around rings
in places we want to initialize both TX rings and XDP rings.
But by making it explicit it is obvious when we are using XDP
rings and when we are using TX rings. Further we don't have
to do ring arithmatic which is error prone. As a proof point
for doing this my first patches used only a single ring structure
and introduced bugs in FCoE code and macvlan code paths.

Second I am aware this is not the most optimized version of
this code possible. I want to get baseline support in using
the most readable format possible and then once this series
is included I will optimize the TX path in another series
of patches.
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe.h

@@ -235,7 +235,11 @@ struct vf_macvlans {
 struct ixgbe_tx_buffer {
 	union ixgbe_adv_tx_desc *next_to_watch;
 	unsigned long time_stamp;
+	union {
 		struct sk_buff *skb;
+		/* XDP uses address ptr on irq_clean */
+		void *data;
+	};
 	unsigned int bytecount;
 	unsigned short gso_segs;
 	__be16 protocol;
@@ -288,6 +292,7 @@ enum ixgbe_ring_state_t {
 	__IXGBE_TX_XPS_INIT_DONE,
 	__IXGBE_TX_DETECT_HANG,
 	__IXGBE_HANG_CHECK_ARMED,
+	__IXGBE_TX_XDP_RING,
 };
 
 #define ring_uses_build_skb(ring) \
@@ -314,6 +319,12 @@ struct ixgbe_fwd_adapter {
 	set_bit(__IXGBE_RX_RSC_ENABLED, &(ring)->state)
 #define clear_ring_rsc_enabled(ring) \
 	clear_bit(__IXGBE_RX_RSC_ENABLED, &(ring)->state)
+#define ring_is_xdp(ring) \
+	test_bit(__IXGBE_TX_XDP_RING, &(ring)->state)
+#define set_ring_xdp(ring) \
+	set_bit(__IXGBE_TX_XDP_RING, &(ring)->state)
+#define clear_ring_xdp(ring) \
+	clear_bit(__IXGBE_TX_XDP_RING, &(ring)->state)
 struct ixgbe_ring {
 	struct ixgbe_ring *next;	/* pointer to next ring in q_vector */
 	struct ixgbe_q_vector *q_vector; /* backpointer to host q_vector */
@@ -380,6 +391,7 @@ enum ixgbe_ring_f_enum {
 #define IXGBE_MAX_FCOE_INDICES		8
 #define MAX_RX_QUEUES			(IXGBE_MAX_FDIR_INDICES + 1)
 #define MAX_TX_QUEUES			(IXGBE_MAX_FDIR_INDICES + 1)
+#define MAX_XDP_QUEUES			(IXGBE_MAX_FDIR_INDICES + 1)
 #define IXGBE_MAX_L2A_QUEUES		4
 #define IXGBE_BAD_L2A_QUEUE		3
 #define IXGBE_MAX_MACVLANS		31
@@ -623,6 +635,10 @@ struct ixgbe_adapter {
 	__be16 vxlan_port;
 	__be16 geneve_port;
 
+	/* XDP */
+	int num_xdp_queues;
+	struct ixgbe_ring *xdp_ring[MAX_XDP_QUEUES];
+
 	/* TX */
 	struct ixgbe_ring *tx_ring[MAX_TX_QUEUES] ____cacheline_aligned_in_smp;
 
@@ -669,6 +685,7 @@ struct ixgbe_adapter {
 
 	u64 tx_busy;
 	unsigned int tx_ring_count;
+	unsigned int xdp_ring_count;
 	unsigned int rx_ring_count;
 
 	u32 link_speed;

drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c

@@ -1071,15 +1071,19 @@ static int ixgbe_set_ringparam(struct net_device *netdev,
 	if (!netif_running(adapter->netdev)) {
 		for (i = 0; i < adapter->num_tx_queues; i++)
 			adapter->tx_ring[i]->count = new_tx_count;
+		for (i = 0; i < adapter->num_xdp_queues; i++)
+			adapter->xdp_ring[i]->count = new_tx_count;
 		for (i = 0; i < adapter->num_rx_queues; i++)
 			adapter->rx_ring[i]->count = new_rx_count;
 		adapter->tx_ring_count = new_tx_count;
+		adapter->xdp_ring_count = new_tx_count;
 		adapter->rx_ring_count = new_rx_count;
 		goto clear_reset;
 	}
 
 	/* allocate temporary buffer to store rings in */
 	i = max_t(int, adapter->num_tx_queues, adapter->num_rx_queues);
+	i = max_t(int, i, adapter->num_xdp_queues);
 	temp_ring = vmalloc(i * sizeof(struct ixgbe_ring));
 
 	if (!temp_ring) {
@@ -1111,12 +1115,33 @@ static int ixgbe_set_ringparam(struct net_device *netdev,
 			}
 		}
 
+		for (i = 0; i < adapter->num_xdp_queues; i++) {
+			memcpy(&temp_ring[i], adapter->xdp_ring[i],
+			       sizeof(struct ixgbe_ring));
+
+			temp_ring[i].count = new_tx_count;
+			err = ixgbe_setup_tx_resources(&temp_ring[i]);
+			if (err) {
+				while (i) {
+					i--;
+					ixgbe_free_tx_resources(&temp_ring[i]);
+				}
+				goto err_setup;
+			}
+		}
+
 		for (i = 0; i < adapter->num_tx_queues; i++) {
 			ixgbe_free_tx_resources(adapter->tx_ring[i]);
 
 			memcpy(adapter->tx_ring[i], &temp_ring[i],
 			       sizeof(struct ixgbe_ring));
 		}
+		for (i = 0; i < adapter->num_xdp_queues; i++) {
+			ixgbe_free_tx_resources(adapter->xdp_ring[i]);
+
+			memcpy(adapter->xdp_ring[i], &temp_ring[i],
+			       sizeof(struct ixgbe_ring));
+		}
 
 		adapter->tx_ring_count = new_tx_count;
 	}

drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c

@@ -267,12 +267,14 @@ static bool ixgbe_cache_ring_sriov(struct ixgbe_adapter *adapter)
  **/
 static bool ixgbe_cache_ring_rss(struct ixgbe_adapter *adapter)
 {
-	int i;
+	int i, reg_idx;
 
 	for (i = 0; i < adapter->num_rx_queues; i++)
 		adapter->rx_ring[i]->reg_idx = i;
-	for (i = 0; i < adapter->num_tx_queues; i++)
-		adapter->tx_ring[i]->reg_idx = i;
+	for (i = 0, reg_idx = 0; i < adapter->num_tx_queues; i++, reg_idx++)
+		adapter->tx_ring[i]->reg_idx = reg_idx;
+	for (i = 0; i < adapter->num_xdp_queues; i++, reg_idx++)
+		adapter->xdp_ring[i]->reg_idx = reg_idx;
 
 	return true;
 }
@@ -308,6 +310,11 @@ static void ixgbe_cache_ring_register(struct ixgbe_adapter *adapter)
 	ixgbe_cache_ring_rss(adapter);
 }
 
+static int ixgbe_xdp_queues(struct ixgbe_adapter *adapter)
+{
+	return adapter->xdp_prog ? nr_cpu_ids : 0;
+}
+
 #define IXGBE_RSS_64Q_MASK	0x3F
 #define IXGBE_RSS_16Q_MASK	0xF
 #define IXGBE_RSS_8Q_MASK	0x7
@@ -382,6 +389,7 @@ static bool ixgbe_set_dcb_sriov_queues(struct ixgbe_adapter *adapter)
 	adapter->num_rx_queues_per_pool = tcs;
 
 	adapter->num_tx_queues = vmdq_i * tcs;
+	adapter->num_xdp_queues = 0;
 	adapter->num_rx_queues = vmdq_i * tcs;
 
 #ifdef IXGBE_FCOE
@@ -479,6 +487,7 @@ static bool ixgbe_set_dcb_queues(struct ixgbe_adapter *adapter)
 		netdev_set_tc_queue(dev, i, rss_i, rss_i * i);
 
 	adapter->num_tx_queues = rss_i * tcs;
+	adapter->num_xdp_queues = 0;
 	adapter->num_rx_queues = rss_i * tcs;
 
 	return true;
@@ -549,6 +558,7 @@ static bool ixgbe_set_sriov_queues(struct ixgbe_adapter *adapter)
 
 	adapter->num_rx_queues = vmdq_i * rss_i;
 	adapter->num_tx_queues = vmdq_i * rss_i;
+	adapter->num_xdp_queues = 0;
 
 	/* disable ATR as it is not supported when VMDq is enabled */
 	adapter->flags &= ~IXGBE_FLAG_FDIR_HASH_CAPABLE;
@@ -669,6 +679,7 @@ static bool ixgbe_set_rss_queues(struct ixgbe_adapter *adapter)
 #endif /* IXGBE_FCOE */
 	adapter->num_rx_queues = rss_i;
 	adapter->num_tx_queues = rss_i;
+	adapter->num_xdp_queues = ixgbe_xdp_queues(adapter);
 
 	return true;
 }
@@ -689,6 +700,7 @@ static void ixgbe_set_num_queues(struct ixgbe_adapter *adapter)
 	/* Start with base case */
 	adapter->num_rx_queues = 1;
 	adapter->num_tx_queues = 1;
+	adapter->num_xdp_queues = 0;
 	adapter->num_rx_pools = adapter->num_rx_queues;
 	adapter->num_rx_queues_per_pool = 1;
 
@@ -719,8 +731,11 @@ static int ixgbe_acquire_msix_vectors(struct ixgbe_adapter *adapter)
 	struct ixgbe_hw *hw = &adapter->hw;
 	int i, vectors, vector_threshold;
 
-	/* We start by asking for one vector per queue pair */
+	/* We start by asking for one vector per queue pair with XDP queues
+	 * being stacked with TX queues.
+	 */
 	vectors = max(adapter->num_rx_queues, adapter->num_tx_queues);
+	vectors = max(vectors, adapter->num_xdp_queues);
 
 	/* It is easy to be greedy for MSI-X vectors. However, it really
 	 * doesn't do much good if we have a lot more vectors than CPUs. We'll
@@ -800,6 +815,8 @@ static void ixgbe_add_ring(struct ixgbe_ring *ring,
  * @v_idx: index of vector in adapter struct
  * @txr_count: total number of Tx rings to allocate
  * @txr_idx: index of first Tx ring to allocate
+ * @xdp_count: total number of XDP rings to allocate
+ * @xdp_idx: index of first XDP ring to allocate
  * @rxr_count: total number of Rx rings to allocate
  * @rxr_idx: index of first Rx ring to allocate
  *
@@ -808,6 +825,7 @@ static void ixgbe_add_ring(struct ixgbe_ring *ring,
 static int ixgbe_alloc_q_vector(struct ixgbe_adapter *adapter,
 				int v_count, int v_idx,
 				int txr_count, int txr_idx,
+				int xdp_count, int xdp_idx,
 				int rxr_count, int rxr_idx)
 {
 	struct ixgbe_q_vector *q_vector;
@@ -817,7 +835,7 @@ static int ixgbe_alloc_q_vector(struct ixgbe_adapter *adapter,
 	int ring_count, size;
 	u8 tcs = netdev_get_num_tc(adapter->netdev);
 
-	ring_count = txr_count + rxr_count;
+	ring_count = txr_count + rxr_count + xdp_count;
 	size = sizeof(struct ixgbe_q_vector) +
 	       (sizeof(struct ixgbe_ring) * ring_count);
 
@@ -909,6 +927,33 @@ static int ixgbe_alloc_q_vector(struct ixgbe_adapter *adapter,
 		ring++;
 	}
 
+	while (xdp_count) {
+		/* assign generic ring traits */
+		ring->dev = &adapter->pdev->dev;
+		ring->netdev = adapter->netdev;
+
+		/* configure backlink on ring */
+		ring->q_vector = q_vector;
+
+		/* update q_vector Tx values */
+		ixgbe_add_ring(ring, &q_vector->tx);
+
+		/* apply Tx specific ring traits */
+		ring->count = adapter->tx_ring_count;
+		ring->queue_index = xdp_idx;
+		set_ring_xdp(ring);
+
+		/* assign ring to adapter */
+		adapter->xdp_ring[xdp_idx] = ring;
+
+		/* update count and index */
+		xdp_count--;
+		xdp_idx++;
+
+		/* push pointer to next ring */
+		ring++;
+	}
+
 	while (rxr_count) {
 		/* assign generic ring traits */
 		ring->dev = &adapter->pdev->dev;
@@ -1002,17 +1047,18 @@ static int ixgbe_alloc_q_vectors(struct ixgbe_adapter *adapter)
 	int q_vectors = adapter->num_q_vectors;
 	int rxr_remaining = adapter->num_rx_queues;
 	int txr_remaining = adapter->num_tx_queues;
-	int rxr_idx = 0, txr_idx = 0, v_idx = 0;
+	int xdp_remaining = adapter->num_xdp_queues;
+	int rxr_idx = 0, txr_idx = 0, xdp_idx = 0, v_idx = 0;
 	int err;
 
 	/* only one q_vector if MSI-X is disabled. */
 	if (!(adapter->flags & IXGBE_FLAG_MSIX_ENABLED))
 		q_vectors = 1;
 
-	if (q_vectors >= (rxr_remaining + txr_remaining)) {
+	if (q_vectors >= (rxr_remaining + txr_remaining + xdp_remaining)) {
 		for (; rxr_remaining; v_idx++) {
 			err = ixgbe_alloc_q_vector(adapter, q_vectors, v_idx,
-						   0, 0, 1, rxr_idx);
+						   0, 0, 0, 0, 1, rxr_idx);
 
 			if (err)
 				goto err_out;
@@ -1026,8 +1072,11 @@ static int ixgbe_alloc_q_vectors(struct ixgbe_adapter *adapter)
 	for (; v_idx < q_vectors; v_idx++) {
 		int rqpv = DIV_ROUND_UP(rxr_remaining, q_vectors - v_idx);
 		int tqpv = DIV_ROUND_UP(txr_remaining, q_vectors - v_idx);
+		int xqpv = DIV_ROUND_UP(xdp_remaining, q_vectors - v_idx);
+
 		err = ixgbe_alloc_q_vector(adapter, q_vectors, v_idx,
 					   tqpv, txr_idx,
+					   xqpv, xdp_idx,
 					   rqpv, rxr_idx);
 
 		if (err)
@@ -1036,14 +1085,17 @@ static int ixgbe_alloc_q_vectors(struct ixgbe_adapter *adapter)
 		/* update counts and index */
 		rxr_remaining -= rqpv;
 		txr_remaining -= tqpv;
+		xdp_remaining -= xqpv;
 		rxr_idx++;
 		txr_idx++;
+		xdp_idx += xqpv;
 	}
 
 	return 0;
 
 err_out:
 	adapter->num_tx_queues = 0;
+	adapter->num_xdp_queues = 0;
 	adapter->num_rx_queues = 0;
 	adapter->num_q_vectors = 0;
 
@@ -1066,6 +1118,7 @@ static void ixgbe_free_q_vectors(struct ixgbe_adapter *adapter)
 	int v_idx = adapter->num_q_vectors;
 
 	adapter->num_tx_queues = 0;
+	adapter->num_xdp_queues = 0;
 	adapter->num_rx_queues = 0;
 	adapter->num_q_vectors = 0;
 
@@ -1172,9 +1225,10 @@ int ixgbe_init_interrupt_scheme(struct ixgbe_adapter *adapter)
 
 	ixgbe_cache_ring_register(adapter);
 
-	e_dev_info("Multiqueue %s: Rx Queue count = %u, Tx Queue count = %u\n",
+	e_dev_info("Multiqueue %s: Rx Queue count = %u, Tx Queue count = %u XDP Queue count = %u\n",
 		   (adapter->num_rx_queues > 1) ? "Enabled" : "Disabled",
-		   adapter->num_rx_queues, adapter->num_tx_queues);
+		   adapter->num_rx_queues, adapter->num_tx_queues,
+		   adapter->num_xdp_queues);
 
 	set_bit(__IXGBE_DOWN, &adapter->state);
 
@@ -1195,6 +1249,7 @@ int ixgbe_init_interrupt_scheme(struct ixgbe_adapter *adapter)
 void ixgbe_clear_interrupt_scheme(struct ixgbe_adapter *adapter)
 {
 	adapter->num_tx_queues = 0;
+	adapter->num_xdp_queues = 0;
 	adapter->num_rx_queues = 0;
 
 	ixgbe_free_q_vectors(adapter);