ixgbevf: Add support for XDP_TX action

This implements the XDP_TX action which is modeled on the ixgbe
implementation. However instead of using CPU id to determine which XDP
queue to use, this uses the received RX queue index, which is similar
to i40e. Doing this eliminates the restriction that number of CPUs not
exceed number of XDP queues that ixgbe has.

Also, based on the number of queues available, the number of TX queues
may be reduced when an XDP program is loaded in order to accommodate the
XDP queues.

Based largely on
commit 33fdc82f ("ixgbe: add support for XDP_TX action")
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbevf/ethtool.c

@@ -269,7 +269,7 @@ static int ixgbevf_set_ringparam(struct net_device *netdev,
 	struct ixgbevf_adapter *adapter = netdev_priv(netdev);
 	struct ixgbevf_ring *tx_ring = NULL, *rx_ring = NULL;
 	u32 new_rx_count, new_tx_count;
-	int i, err = 0;
+	int i, j, err = 0;
 
 	if ((ring->rx_mini_pending) || (ring->rx_jumbo_pending))
 		return -EINVAL;
@@ -293,15 +293,19 @@ static int ixgbevf_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;
 	}
 
 	if (new_tx_count != adapter->tx_ring_count) {
-		tx_ring = vmalloc(adapter->num_tx_queues * sizeof(*tx_ring));
+		tx_ring = vmalloc((adapter->num_tx_queues +
+				   adapter->num_xdp_queues) * sizeof(*tx_ring));
 		if (!tx_ring) {
 			err = -ENOMEM;
 			goto clear_reset;
@@ -324,6 +328,24 @@ static int ixgbevf_set_ringparam(struct net_device *netdev,
 				goto clear_reset;
 			}
 		}
+
+		for (j = 0; j < adapter->num_xdp_queues; i++, j++) {
+			/* clone ring and setup updated count */
+			tx_ring[i] = *adapter->xdp_ring[j];
+			tx_ring[i].count = new_tx_count;
+			err = ixgbevf_setup_tx_resources(&tx_ring[i]);
+			if (err) {
+				while (i) {
+					i--;
+					ixgbevf_free_tx_resources(&tx_ring[i]);
+				}
+
+				vfree(tx_ring);
+				tx_ring = NULL;
+
+				goto clear_reset;
+			}
+		}
 	}
 
 	if (new_rx_count != adapter->rx_ring_count) {
@@ -368,6 +390,12 @@ static int ixgbevf_set_ringparam(struct net_device *netdev,
 		}
 		adapter->tx_ring_count = new_tx_count;
 
+		for (j = 0; j < adapter->num_xdp_queues; i++, j++) {
+			ixgbevf_free_tx_resources(adapter->xdp_ring[j]);
+			*adapter->xdp_ring[j] = tx_ring[i];
+		}
+		adapter->xdp_ring_count = new_tx_count;
+
 		vfree(tx_ring);
 		tx_ring = NULL;
 	}
@@ -390,7 +418,8 @@ static int ixgbevf_set_ringparam(struct net_device *netdev,
 clear_reset:
 	/* free Tx resources if Rx error is encountered */
 	if (tx_ring) {
-		for (i = 0; i < adapter->num_tx_queues; i++)
+		for (i = 0;
+		     i < adapter->num_tx_queues + adapter->num_xdp_queues; i++)
 			ixgbevf_free_tx_resources(&tx_ring[i]);
 		vfree(tx_ring);
 	}

drivers/net/ethernet/intel/ixgbevf/ixgbevf.h

@@ -52,7 +52,11 @@
 struct ixgbevf_tx_buffer {
 	union ixgbe_adv_tx_desc *next_to_watch;
 	unsigned long time_stamp;
-	struct sk_buff *skb;
+	union {
+		struct sk_buff *skb;
+		/* XDP uses address ptr on irq_clean */
+		void *data;
+	};
 	unsigned int bytecount;
 	unsigned short gso_segs;
 	__be16 protocol;
@@ -95,8 +99,16 @@ enum ixgbevf_ring_state_t {
 	__IXGBEVF_RX_BUILD_SKB_ENABLED,
 	__IXGBEVF_TX_DETECT_HANG,
 	__IXGBEVF_HANG_CHECK_ARMED,
+	__IXGBEVF_TX_XDP_RING,
 };
 
+#define ring_is_xdp(ring) \
+		test_bit(__IXGBEVF_TX_XDP_RING, &(ring)->state)
+#define set_ring_xdp(ring) \
+		set_bit(__IXGBEVF_TX_XDP_RING, &(ring)->state)
+#define clear_ring_xdp(ring) \
+		clear_bit(__IXGBEVF_TX_XDP_RING, &(ring)->state)
+
 struct ixgbevf_ring {
 	struct ixgbevf_ring *next;
 	struct ixgbevf_q_vector *q_vector;	/* backpointer to q_vector */
@@ -139,6 +151,7 @@ struct ixgbevf_ring {
 
 #define MAX_RX_QUEUES IXGBE_VF_MAX_RX_QUEUES
 #define MAX_TX_QUEUES IXGBE_VF_MAX_TX_QUEUES
+#define MAX_XDP_QUEUES IXGBE_VF_MAX_TX_QUEUES
 #define IXGBEVF_MAX_RSS_QUEUES		2
 #define IXGBEVF_82599_RETA_SIZE		128	/* 128 entries */
 #define IXGBEVF_X550_VFRETA_SIZE	64	/* 64 entries */
@@ -339,6 +352,10 @@ struct ixgbevf_adapter {
 	u32 eims_enable_mask;
 	u32 eims_other;
 
+	/* XDP */
+	int num_xdp_queues;
+	struct ixgbevf_ring *xdp_ring[MAX_XDP_QUEUES];
+
 	/* TX */
 	int num_tx_queues;
 	struct ixgbevf_ring *tx_ring[MAX_TX_QUEUES]; /* One per active queue */
@@ -373,6 +390,7 @@ struct ixgbevf_adapter {
 	unsigned long state;
 	u64 tx_busy;
 	unsigned int tx_ring_count;
+	unsigned int xdp_ring_count;
 	unsigned int rx_ring_count;
 
 	u8 __iomem *io_addr; /* Mainly for iounmap use */