Merge branch 'xdp'

Brenden Blanco says:

====================
Add driver bpf hook for early packet drop and forwarding

This patch set introduces new infrastructure for programmatically
processing packets in the earliest stages of rx, as part of an effort
others are calling eXpress Data Path (XDP) [1]. Start this effort by
introducing a new bpf program type for early packet filtering, before
even an skb has been allocated.

Extend on this with the ability to modify packet data and send back out
on the same port.

Patch 1 adds an API for bulk bpf prog refcnt incrememnt.
Patch 2 introduces the new prog type and helpers for validating the bpf
  program. A new userspace struct is defined containing only data and
  data_end as fields, with others to follow in the future.
In patch 3, create a new ndo to pass the fd to supported drivers.
In patch 4, expose a new rtnl option to userspace.
In patch 5, enable support in mlx4 driver.
In patch 6, create a sample drop and count program. With single core,
  achieved ~20 Mpps drop rate on a 40G ConnectX3-Pro. This includes
  packet data access, bpf array lookup, and increment.
In patch 7, add a page recycle facility to mlx4 rx, enabled when xdp is
  active.
In patch 8, add the XDP_TX type to bpf.h
In patch 9, add helper in tx patch for writing tx_desc
In patch 10, add support in mlx4 for packet data write and forwarding
In patch 11, turn on packet write support in the bpf verifier
In patch 12, add a sample program for packet write and forwarding. With
  single core, achieved ~10 Mpps rewrite and forwarding.

[1] https://github.com/iovisor/bpf-docs/blob/master/Express_Data_Path.pdf

v10:
 1/12: Add bulk refcnt api.
 5/12: Move prog from priv to ring. This attribute is still only set
   globally, but the path to finer granularity should be clear. No lock
   is taken, so some rings may operate on older programs for a time (one
   napi loop). Looked into options such as napi_synchronize, but they
   were deemed too slow (calls to msleep).
   Rename prog to xdp_prog. Add xdp_ring_num to help with accounting,
   used more heavily in later patches.
 7/12: Adjust to use per-ring xdp prog. Use priv->xdp_ring_num where
   before priv->prog was used to determine buffer allocations.
 9/12: Add cpu_to_be16 to vlan_tag in mxl4_en_xmit(). Remove unused variable
   from mlx4_en_xmit and unused params from build_inline_wqe.

v9:
 4/11: Add missing newline in en_err message.
 6/11: Move page_cache cleanup from mlx4_en_destroy_rx_ring to
   mlx4_en_deactivate_rx_ring. Move mlx4_en_moderation_update back to
   static. Remove calls to mlx4_en_alloc/free_resources in mlx4_xdp_set.
   Adopt instead the approach of mlx4_en_change_mtu to use a watchdog.
 9/11: Use a per-ring function pointer in tx to separate out the code
   for regular and recycle paths of tx completion handling. Add a helper
   function to init the recycle ring and callback, called just after
   activating tx. Remove extra tx ring resource requirement, and instead
   steal from the upper rings. This helps to avoid needing
   mlx4_en_alloc_resources. Add some hopefully meaningful error
   messages for the various error cases. Reverted some of the
   hard-to-follow logic that was accounting for the extra tx rings.

v8:
 1/11: Reduce WARN_ONCE to single line. Also, change act param of that
   function to u32 to match return type of bpf_prog_run_xdp.
 2/11: Clarify locking semantics in ndo comment.
 4/11: Add en_err warning in mlx4_xdp_set on num_frags/mtu violation.

v7:
 Addressing two of the major discussion points: return codes and ndo.
 The rest will be taken as todo items for separate patches.

 Add an XDP_ABORTED type, which explicitly falls through to DROP. The
 same result must be taken for the default case as well, as it is now
 well-defined API behavior.

 Merge ndo_xdp_* into a single ndo. The style is similar to
 ndo_setup_tc, but with less unidirectional naming convention. The IFLA
 parameter names are unchanged.

 TODOs:
 Add ethtool per-ring stats for aborted, default cases, maybe even drop
 and tx as well.
 Avoid duplicate dma sync operation in XDP_PASS case as mentioned by
 Saeed.

  1/12: Add XDP_ABORTED enum, reword API comment, and update commit
   message.
  2/12: Rewrite ndo_xdp_*() into single ndo_xdp() with type/union style
    calling convention.
  3/12: Switch to ndo_xdp callback.
  4/12: Add XDP_ABORTED case as a fall-through to XDP_DROP. Implement
    ndo_xdp.
 12/12: Dropped, this will need some more work.

v6:
  2/12: drop unnecessary netif_device_present check
  4/12, 6/12, 9/12: Reorder default case statement above drop case to
    remove some copy/paste.

v5:
  0/12: Rebase and remove previous 1/13 patch
  1/12: Fix nits from Daniel. Left the (void *) cast as-is, to be fixed
    in future. Add bpf_warn_invalid_xdp_action() helper, to be used when
    out of bounds action is returned by the program. Add a comment to
    bpf.h denoting the undefined nature of out of bounds returns.
  2/12: Switch to using bpf_prog_get_type(). Rename ndo_xdp_get() to
    ndo_xdp_attached().
  3/12: Add IFLA_XDP as a nested type, and add the associated nla_policy
    for the new subtypes IFLA_XDP_FD and IFLA_XDP_ATTACHED.
  4/12: Fixup the use of READ_ONCE in the ndos. Add a user of
    bpf_warn_invalid_xdp_action helper.
  5/12: Adjust to using the nested netlink options.
  6/12: kbuild was complaining about overflow of u16 on tile
    architecture...bump frag_stride to u32. The page_offset member that
    is computed from this was already u32.

v4:
  2/12: Add inline helper for calling xdp bpf prog under rcu
  3/12: Add detail to ndo comments
  5/12: Remove mlx4_call_xdp and use inline helper instead.
  6/12: Fix checkpatch complaints
  9/12: Introduce new patch 9/12 with common helper for tx_desc write
    Refactor to use common tx_desc write helper
 11/12: Fix checkpatch complaints

v3:
  Rewrite from v2 trying to incorporate feedback from multiple sources.
  Specifically, add ability to forward packets out the same port and
    allow packet modification.
  For packet forwarding, the driver reserves a dedicated set of tx rings
    for exclusive use by xdp. Upon completion, the pages on this ring are
    recycled directly back to a small per-rx-ring page cache without
    being dma unmapped.
  Use of the percpu skb is dropped in favor of a lightweight struct
    xdp_buff. The direct packet access feature is leveraged to remove
    dependence on the skb.
  The mlx4 driver implementation allocates a page-per-packet and maps it
    in PCI_DMA_BIDIRECTIONAL mode when the bpf program is activated.
  Naming is converted to use "xdp" instead of "phys_dev".

v2:
  1/5: Drop xdp from types, instead consistently use bpf_phys_dev_
    Introduce enum for return values from phys_dev hook
  2/5: Move prog->type check to just before invoking ndo
    Change ndo to take a bpf_prog * instead of fd
    Add ndo_bpf_get rather than keeping a bool in the netdev struct
  3/5: Use ndo_bpf_get to fetch bool
  4/5: Enforce that only 1 frag is ever given to bpf prog by disallowing
    mtu to increase beyond FRAG_SZ0 when bpf prog is running, or conversely
    to set a bpf prog when priv->num_frags > 1
    Rename pseudo_skb to bpf_phys_dev_md
    Implement ndo_bpf_get
    Add dma sync just before invoking prog
    Check for explicit bpf return code rather than nonzero
    Remove increment of rx_dropped
  5/5: Use explicit bpf return code in example
    Update commit log with higher pps numbers
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/infiniband/hw/mlx4/qp.c

@@ -232,7 +232,7 @@ static void stamp_send_wqe(struct mlx4_ib_qp *qp, int n, int size)
 		}
 	} else {
 		ctrl = buf = get_send_wqe(qp, n & (qp->sq.wqe_cnt - 1));
-		s = (ctrl->fence_size & 0x3f) << 4;
+		s = (ctrl->qpn_vlan.fence_size & 0x3f) << 4;
 		for (i = 64; i < s; i += 64) {
 			wqe = buf + i;
 			*wqe = cpu_to_be32(0xffffffff);
@@ -264,7 +264,7 @@ static void post_nop_wqe(struct mlx4_ib_qp *qp, int n, int size)
 		inl->byte_count = cpu_to_be32(1 << 31 | (size - s - sizeof *inl));
 	}
 	ctrl->srcrb_flags = 0;
-	ctrl->fence_size = size / 16;
+	ctrl->qpn_vlan.fence_size = size / 16;
 	/*
 	 * Make sure descriptor is fully written before setting ownership bit
 	 * (because HW can start executing as soon as we do).
@@ -1992,7 +1992,8 @@ static int __mlx4_ib_modify_qp(struct ib_qp *ibqp,
 			ctrl = get_send_wqe(qp, i);
 			ctrl->owner_opcode = cpu_to_be32(1 << 31);
 			if (qp->sq_max_wqes_per_wr == 1)
-				ctrl->fence_size = 1 << (qp->sq.wqe_shift - 4);
+				ctrl->qpn_vlan.fence_size =
+						1 << (qp->sq.wqe_shift - 4);
 
 			stamp_send_wqe(qp, i, 1 << qp->sq.wqe_shift);
 		}
@@ -3169,8 +3170,8 @@ int mlx4_ib_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr,
 		wmb();
 		*lso_wqe = lso_hdr_sz;
 
-		ctrl->fence_size = (wr->send_flags & IB_SEND_FENCE ?
-				    MLX4_WQE_CTRL_FENCE : 0) | size;
+		ctrl->qpn_vlan.fence_size = (wr->send_flags & IB_SEND_FENCE ?
+					     MLX4_WQE_CTRL_FENCE : 0) | size;
 
 		/*
 		 * Make sure descriptor is fully written before

drivers/net/ethernet/mellanox/mlx4/en_ethtool.c

@@ -1722,6 +1722,12 @@ static int mlx4_en_set_channels(struct net_device *dev,
 	    !channel->tx_count || !channel->rx_count)
 		return -EINVAL;
 
+	if (channel->tx_count * MLX4_EN_NUM_UP <= priv->xdp_ring_num) {
+		en_err(priv, "Minimum %d tx channels required with XDP on\n",
+		       priv->xdp_ring_num / MLX4_EN_NUM_UP + 1);
+		return -EINVAL;
+	}
+
 	mutex_lock(&mdev->state_lock);
 	if (priv->port_up) {
 		port_up = 1;
@@ -1740,7 +1746,8 @@ static int mlx4_en_set_channels(struct net_device *dev,
 		goto out;
 	}
 
-	netif_set_real_num_tx_queues(dev, priv->tx_ring_num);
+	netif_set_real_num_tx_queues(dev, priv->tx_ring_num -
+							priv->xdp_ring_num);
 	netif_set_real_num_rx_queues(dev, priv->rx_ring_num);
 
 	if (dev->num_tc)

drivers/net/ethernet/mellanox/mlx4/en_netdev.c

@@ -31,6 +31,7 @@
  *
  */
 
+#include <linux/bpf.h>
 #include <linux/etherdevice.h>
 #include <linux/tcp.h>
 #include <linux/if_vlan.h>
@@ -1521,6 +1522,24 @@ static void mlx4_en_free_affinity_hint(struct mlx4_en_priv *priv, int ring_idx)
 	free_cpumask_var(priv->rx_ring[ring_idx]->affinity_mask);
 }
 
+static void mlx4_en_init_recycle_ring(struct mlx4_en_priv *priv,
+				      int tx_ring_idx)
+{
+	struct mlx4_en_tx_ring *tx_ring = priv->tx_ring[tx_ring_idx];
+	int rr_index;
+
+	rr_index = (priv->xdp_ring_num - priv->tx_ring_num) + tx_ring_idx;
+	if (rr_index >= 0) {
+		tx_ring->free_tx_desc = mlx4_en_recycle_tx_desc;
+		tx_ring->recycle_ring = priv->rx_ring[rr_index];
+		en_dbg(DRV, priv,
+		       "Set tx_ring[%d]->recycle_ring = rx_ring[%d]\n",
+		       tx_ring_idx, rr_index);
+	} else {
+		tx_ring->recycle_ring = NULL;
+	}
+}
+
 int mlx4_en_start_port(struct net_device *dev)
 {
 	struct mlx4_en_priv *priv = netdev_priv(dev);
@@ -1643,6 +1662,8 @@ int mlx4_en_start_port(struct net_device *dev)
 		}
 		tx_ring->tx_queue = netdev_get_tx_queue(dev, i);
 
+		mlx4_en_init_recycle_ring(priv, i);
+
 		/* Arm CQ for TX completions */
 		mlx4_en_arm_cq(priv, cq);
 
@@ -2112,6 +2133,11 @@ static int mlx4_en_change_mtu(struct net_device *dev, int new_mtu)
 		en_err(priv, "Bad MTU size:%d.\n", new_mtu);
 		return -EPERM;
 	}
+	if (priv->xdp_ring_num && MLX4_EN_EFF_MTU(new_mtu) > FRAG_SZ0) {
+		en_err(priv, "MTU size:%d requires frags but XDP running\n",
+		       new_mtu);
+		return -EOPNOTSUPP;
+	}
 	dev->mtu = new_mtu;
 
 	if (netif_running(dev)) {
@@ -2520,6 +2546,103 @@ static int mlx4_en_set_tx_maxrate(struct net_device *dev, int queue_index, u32 m
 	return err;
 }
 
+static int mlx4_xdp_set(struct net_device *dev, struct bpf_prog *prog)
+{
+	struct mlx4_en_priv *priv = netdev_priv(dev);
+	struct mlx4_en_dev *mdev = priv->mdev;
+	struct bpf_prog *old_prog;
+	int xdp_ring_num;
+	int port_up = 0;
+	int err;
+	int i;
+
+	xdp_ring_num = prog ? ALIGN(priv->rx_ring_num, MLX4_EN_NUM_UP) : 0;
+
+	/* No need to reconfigure buffers when simply swapping the
+	 * program for a new one.
+	 */
+	if (priv->xdp_ring_num == xdp_ring_num) {
+		if (prog) {
+			prog = bpf_prog_add(prog, priv->rx_ring_num - 1);
+			if (IS_ERR(prog))
+				return PTR_ERR(prog);
+		}
+		for (i = 0; i < priv->rx_ring_num; i++) {
+			/* This xchg is paired with READ_ONCE in the fastpath */
+			old_prog = xchg(&priv->rx_ring[i]->xdp_prog, prog);
+			if (old_prog)
+				bpf_prog_put(old_prog);
+		}
+		return 0;
+	}
+
+	if (priv->num_frags > 1) {
+		en_err(priv, "Cannot set XDP if MTU requires multiple frags\n");
+		return -EOPNOTSUPP;
+	}
+
+	if (priv->tx_ring_num < xdp_ring_num + MLX4_EN_NUM_UP) {
+		en_err(priv,
+		       "Minimum %d tx channels required to run XDP\n",
+		       (xdp_ring_num + MLX4_EN_NUM_UP) / MLX4_EN_NUM_UP);
+		return -EINVAL;
+	}
+
+	if (prog) {
+		prog = bpf_prog_add(prog, priv->rx_ring_num - 1);
+		if (IS_ERR(prog))
+			return PTR_ERR(prog);
+	}
+
+	mutex_lock(&mdev->state_lock);
+	if (priv->port_up) {
+		port_up = 1;
+		mlx4_en_stop_port(dev, 1);
+	}
+
+	priv->xdp_ring_num = xdp_ring_num;
+	netif_set_real_num_tx_queues(dev, priv->tx_ring_num -
+							priv->xdp_ring_num);
+
+	for (i = 0; i < priv->rx_ring_num; i++) {
+		old_prog = xchg(&priv->rx_ring[i]->xdp_prog, prog);
+		if (old_prog)
+			bpf_prog_put(old_prog);
+	}
+
+	if (port_up) {
+		err = mlx4_en_start_port(dev);
+		if (err) {
+			en_err(priv, "Failed starting port %d for XDP change\n",
+			       priv->port);
+			queue_work(mdev->workqueue, &priv->watchdog_task);
+		}
+	}
+
+	mutex_unlock(&mdev->state_lock);
+	return 0;
+}
+
+static bool mlx4_xdp_attached(struct net_device *dev)
+{
+	struct mlx4_en_priv *priv = netdev_priv(dev);
+
+	return !!priv->xdp_ring_num;
+}
+
+static int mlx4_xdp(struct net_device *dev, struct netdev_xdp *xdp)
+{
+	switch (xdp->command) {
+	case XDP_SETUP_PROG:
+		return mlx4_xdp_set(dev, xdp->prog);
+	case XDP_QUERY_PROG:
+		xdp->prog_attached = mlx4_xdp_attached(dev);
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
 static const struct net_device_ops mlx4_netdev_ops = {
 	.ndo_open		= mlx4_en_open,
 	.ndo_stop		= mlx4_en_close,
@@ -2548,6 +2671,7 @@ static const struct net_device_ops mlx4_netdev_ops = {
 	.ndo_udp_tunnel_del	= mlx4_en_del_vxlan_port,
 	.ndo_features_check	= mlx4_en_features_check,
 	.ndo_set_tx_maxrate	= mlx4_en_set_tx_maxrate,
+	.ndo_xdp		= mlx4_xdp,
 };
 
 static const struct net_device_ops mlx4_netdev_ops_master = {
@@ -2584,6 +2708,7 @@ static const struct net_device_ops mlx4_netdev_ops_master = {
 	.ndo_udp_tunnel_del	= mlx4_en_del_vxlan_port,
 	.ndo_features_check	= mlx4_en_features_check,
 	.ndo_set_tx_maxrate	= mlx4_en_set_tx_maxrate,
+	.ndo_xdp		= mlx4_xdp,
 };
 
 struct mlx4_en_bond {

drivers/net/ethernet/mellanox/mlx4/en_rx.c

@@ -32,6 +32,7 @@
  */
 
 #include <net/busy_poll.h>
+#include <linux/bpf.h>
 #include <linux/mlx4/cq.h>
 #include <linux/slab.h>
 #include <linux/mlx4/qp.h>
@@ -57,7 +58,7 @@ static int mlx4_alloc_pages(struct mlx4_en_priv *priv,
 	struct page *page;
 	dma_addr_t dma;
 
-	for (order = MLX4_EN_ALLOC_PREFER_ORDER; ;) {
+	for (order = frag_info->order; ;) {
 		gfp_t gfp = _gfp;
 
 		if (order)
@@ -70,7 +71,7 @@ static int mlx4_alloc_pages(struct mlx4_en_priv *priv,
 			return -ENOMEM;
 	}
 	dma = dma_map_page(priv->ddev, page, 0, PAGE_SIZE << order,
-			   PCI_DMA_FROMDEVICE);
+			   frag_info->dma_dir);
 	if (dma_mapping_error(priv->ddev, dma)) {
 		put_page(page);
 		return -ENOMEM;
@@ -124,7 +125,8 @@ out:
 	while (i--) {
 		if (page_alloc[i].page != ring_alloc[i].page) {
 			dma_unmap_page(priv->ddev, page_alloc[i].dma,
-				page_alloc[i].page_size, PCI_DMA_FROMDEVICE);
+				page_alloc[i].page_size,
+				priv->frag_info[i].dma_dir);
 			page = page_alloc[i].page;
 			/* Revert changes done by mlx4_alloc_pages */
 			page_ref_sub(page, page_alloc[i].page_size /
@@ -145,7 +147,7 @@ static void mlx4_en_free_frag(struct mlx4_en_priv *priv,
 
 	if (next_frag_end > frags[i].page_size)
 		dma_unmap_page(priv->ddev, frags[i].dma, frags[i].page_size,
-			       PCI_DMA_FROMDEVICE);
+			       frag_info->dma_dir);
 
 	if (frags[i].page)
 		put_page(frags[i].page);
@@ -176,7 +178,8 @@ out:
 
 		page_alloc = &ring->page_alloc[i];
 		dma_unmap_page(priv->ddev, page_alloc->dma,
-			       page_alloc->page_size, PCI_DMA_FROMDEVICE);
+			       page_alloc->page_size,
+			       priv->frag_info[i].dma_dir);
 		page = page_alloc->page;
 		/* Revert changes done by mlx4_alloc_pages */
 		page_ref_sub(page, page_alloc->page_size /
@@ -201,7 +204,7 @@ static void mlx4_en_destroy_allocator(struct mlx4_en_priv *priv,
 		       i, page_count(page_alloc->page));
 
 		dma_unmap_page(priv->ddev, page_alloc->dma,
-				page_alloc->page_size, PCI_DMA_FROMDEVICE);
+				page_alloc->page_size, frag_info->dma_dir);
 		while (page_alloc->page_offset + frag_info->frag_stride <
 		       page_alloc->page_size) {
 			put_page(page_alloc->page);
@@ -244,6 +247,12 @@ static int mlx4_en_prepare_rx_desc(struct mlx4_en_priv *priv,
 	struct mlx4_en_rx_alloc *frags = ring->rx_info +
 					(index << priv->log_rx_info);
 
+	if (ring->page_cache.index > 0) {
+		frags[0] = ring->page_cache.buf[--ring->page_cache.index];
+		rx_desc->data[0].addr = cpu_to_be64(frags[0].dma);
+		return 0;
+	}
+
 	return mlx4_en_alloc_frags(priv, rx_desc, frags, ring->page_alloc, gfp);
 }
 
@@ -502,6 +511,24 @@ void mlx4_en_recover_from_oom(struct mlx4_en_priv *priv)
 	}
 }
 
+/* When the rx ring is running in page-per-packet mode, a released frame can go
+ * directly into a small cache, to avoid unmapping or touching the page
+ * allocator. In bpf prog performance scenarios, buffers are either forwarded
+ * or dropped, never converted to skbs, so every page can come directly from
+ * this cache when it is sized to be a multiple of the napi budget.
+ */
+bool mlx4_en_rx_recycle(struct mlx4_en_rx_ring *ring,
+			struct mlx4_en_rx_alloc *frame)
+{
+	struct mlx4_en_page_cache *cache = &ring->page_cache;
+
+	if (cache->index >= MLX4_EN_CACHE_SIZE)
+		return false;
+
+	cache->buf[cache->index++] = *frame;
+	return true;
+}
+
 void mlx4_en_destroy_rx_ring(struct mlx4_en_priv *priv,
 			     struct mlx4_en_rx_ring **pring,
 			     u32 size, u16 stride)
@@ -509,6 +536,8 @@ void mlx4_en_destroy_rx_ring(struct mlx4_en_priv *priv,
 	struct mlx4_en_dev *mdev = priv->mdev;
 	struct mlx4_en_rx_ring *ring = *pring;
 
+	if (ring->xdp_prog)
+		bpf_prog_put(ring->xdp_prog);
 	mlx4_free_hwq_res(mdev->dev, &ring->wqres, size * stride + TXBB_SIZE);
 	vfree(ring->rx_info);
 	ring->rx_info = NULL;
@@ -522,6 +551,16 @@ void mlx4_en_destroy_rx_ring(struct mlx4_en_priv *priv,
 void mlx4_en_deactivate_rx_ring(struct mlx4_en_priv *priv,
 				struct mlx4_en_rx_ring *ring)
 {
+	int i;
+
+	for (i = 0; i < ring->page_cache.index; i++) {
+		struct mlx4_en_rx_alloc *frame = &ring->page_cache.buf[i];
+
+		dma_unmap_page(priv->ddev, frame->dma, frame->page_size,
+			       priv->frag_info[0].dma_dir);
+		put_page(frame->page);
+	}
+	ring->page_cache.index = 0;
 	mlx4_en_free_rx_buf(priv, ring);
 	if (ring->stride <= TXBB_SIZE)
 		ring->buf -= TXBB_SIZE;
@@ -743,7 +782,10 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud
 	struct mlx4_en_rx_ring *ring = priv->rx_ring[cq->ring];
 	struct mlx4_en_rx_alloc *frags;
 	struct mlx4_en_rx_desc *rx_desc;
+	struct bpf_prog *xdp_prog;
+	int doorbell_pending;
 	struct sk_buff *skb;
+	int tx_index;
 	int index;
 	int nr;
 	unsigned int length;
@@ -759,6 +801,10 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud
 	if (budget <= 0)
 		return polled;
 
+	xdp_prog = READ_ONCE(ring->xdp_prog);
+	doorbell_pending = 0;
+	tx_index = (priv->tx_ring_num - priv->xdp_ring_num) + cq->ring;
+
 	/* We assume a 1:1 mapping between CQEs and Rx descriptors, so Rx
 	 * descriptor offset can be deduced from the CQE index instead of
 	 * reading 'cqe->index' */
@@ -835,6 +881,43 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud
 		l2_tunnel = (dev->hw_enc_features & NETIF_F_RXCSUM) &&
 			(cqe->vlan_my_qpn & cpu_to_be32(MLX4_CQE_L2_TUNNEL));
 
+		/* A bpf program gets first chance to drop the packet. It may
+		 * read bytes but not past the end of the frag.
+		 */
+		if (xdp_prog) {
+			struct xdp_buff xdp;
+			dma_addr_t dma;
+			u32 act;
+
+			dma = be64_to_cpu(rx_desc->data[0].addr);
+			dma_sync_single_for_cpu(priv->ddev, dma,
+						priv->frag_info[0].frag_size,
+						DMA_FROM_DEVICE);
+
+			xdp.data = page_address(frags[0].page) +
+							frags[0].page_offset;
+			xdp.data_end = xdp.data + length;
+
+			act = bpf_prog_run_xdp(xdp_prog, &xdp);
+			switch (act) {
+			case XDP_PASS:
+				break;
+			case XDP_TX:
+				if (!mlx4_en_xmit_frame(frags, dev,
+							length, tx_index,
+							&doorbell_pending))
+					goto consumed;
+				break;
+			default:
+				bpf_warn_invalid_xdp_action(act);
+			case XDP_ABORTED:
+			case XDP_DROP:
+				if (mlx4_en_rx_recycle(ring, frags))
+					goto consumed;
+				goto next;
+			}
+		}
+
 		if (likely(dev->features & NETIF_F_RXCSUM)) {
 			if (cqe->status & cpu_to_be16(MLX4_CQE_STATUS_TCP |
 						      MLX4_CQE_STATUS_UDP)) {
@@ -986,6 +1069,7 @@ next:
 		for (nr = 0; nr < priv->num_frags; nr++)
 			mlx4_en_free_frag(priv, frags, nr);
 
+consumed:
 		++cq->mcq.cons_index;
 		index = (cq->mcq.cons_index) & ring->size_mask;
 		cqe = mlx4_en_get_cqe(cq->buf, index, priv->cqe_size) + factor;
@@ -994,6 +1078,9 @@ next:
 	}
 
 out:
+	if (doorbell_pending)
+		mlx4_en_xmit_doorbell(priv->tx_ring[tx_index]);
+
 	AVG_PERF_COUNTER(priv->pstats.rx_coal_avg, polled);
 	mlx4_cq_set_ci(&cq->mcq);
 	wmb(); /* ensure HW sees CQ consumer before we post new buffers */
@@ -1061,22 +1148,35 @@ static const int frag_sizes[] = {
 
 void mlx4_en_calc_rx_buf(struct net_device *dev)
 {
+	enum dma_data_direction dma_dir = PCI_DMA_FROMDEVICE;
 	struct mlx4_en_priv *priv = netdev_priv(dev);
-	/* VLAN_HLEN is added twice,to support skb vlan tagged with multiple
-	 * headers. (For example: ETH_P_8021Q and ETH_P_8021AD).
-	 */
-	int eff_mtu = dev->mtu + ETH_HLEN + (2 * VLAN_HLEN);
+	int eff_mtu = MLX4_EN_EFF_MTU(dev->mtu);
+	int order = MLX4_EN_ALLOC_PREFER_ORDER;
+	u32 align = SMP_CACHE_BYTES;
 	int buf_size = 0;
 	int i = 0;
 
+	/* bpf requires buffers to be set up as 1 packet per page.
+	 * This only works when num_frags == 1.
+	 */
+	if (priv->xdp_ring_num) {
+		dma_dir = PCI_DMA_BIDIRECTIONAL;
+		/* This will gain efficient xdp frame recycling at the expense
+		 * of more costly truesize accounting
+		 */
+		align = PAGE_SIZE;
+		order = 0;
+	}
+
 	while (buf_size < eff_mtu) {
+		priv->frag_info[i].order = order;
 		priv->frag_info[i].frag_size =
 			(eff_mtu > buf_size + frag_sizes[i]) ?
 				frag_sizes[i] : eff_mtu - buf_size;
 		priv->frag_info[i].frag_prefix_size = buf_size;
 		priv->frag_info[i].frag_stride =
-				ALIGN(priv->frag_info[i].frag_size,
-				      SMP_CACHE_BYTES);
+				ALIGN(priv->frag_info[i].frag_size, align);
+		priv->frag_info[i].dma_dir = dma_dir;
 		buf_size += priv->frag_info[i].frag_size;
 		i++;
 	}

drivers/net/ethernet/mellanox/mlx4/en_tx.c

@@ -196,6 +196,7 @@ int mlx4_en_activate_tx_ring(struct mlx4_en_priv *priv,
 	ring->last_nr_txbb = 1;
 	memset(ring->tx_info, 0, ring->size * sizeof(struct mlx4_en_tx_info));
 	memset(ring->buf, 0, ring->buf_size);
+	ring->free_tx_desc = mlx4_en_free_tx_desc;
 
 	ring->qp_state = MLX4_QP_STATE_RST;
 	ring->doorbell_qpn = cpu_to_be32(ring->qp.qpn << 8);
@@ -265,10 +266,10 @@ static void mlx4_en_stamp_wqe(struct mlx4_en_priv *priv,
 }
 
 
-static u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv,
-				struct mlx4_en_tx_ring *ring,
-				int index, u8 owner, u64 timestamp,
-				int napi_mode)
+u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv,
+			 struct mlx4_en_tx_ring *ring,
+			 int index, u8 owner, u64 timestamp,
+			 int napi_mode)
 {
 	struct mlx4_en_tx_info *tx_info = &ring->tx_info[index];
 	struct mlx4_en_tx_desc *tx_desc = ring->buf + index * TXBB_SIZE;
@@ -344,6 +345,27 @@ static u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv,
 	return tx_info->nr_txbb;
 }
 
+u32 mlx4_en_recycle_tx_desc(struct mlx4_en_priv *priv,
+			    struct mlx4_en_tx_ring *ring,
+			    int index, u8 owner, u64 timestamp,
+			    int napi_mode)
+{
+	struct mlx4_en_tx_info *tx_info = &ring->tx_info[index];
+	struct mlx4_en_rx_alloc frame = {
+		.page = tx_info->page,
+		.dma = tx_info->map0_dma,
+		.page_offset = 0,
+		.page_size = PAGE_SIZE,
+	};
+
+	if (!mlx4_en_rx_recycle(ring->recycle_ring, &frame)) {
+		dma_unmap_page(priv->ddev, tx_info->map0_dma,
+			       PAGE_SIZE, priv->frag_info[0].dma_dir);
+		put_page(tx_info->page);
+	}
+
+	return tx_info->nr_txbb;
+}
 
 int mlx4_en_free_tx_buf(struct net_device *dev, struct mlx4_en_tx_ring *ring)
 {
@@ -362,7 +384,7 @@ int mlx4_en_free_tx_buf(struct net_device *dev, struct mlx4_en_tx_ring *ring)
 	}
 
 	while (ring->cons != ring->prod) {
-		ring->last_nr_txbb = mlx4_en_free_tx_desc(priv, ring,
+		ring->last_nr_txbb = ring->free_tx_desc(priv, ring,
 						ring->cons & ring->size_mask,
 						!!(ring->cons & ring->size), 0,
 						0 /* Non-NAPI caller */);
@@ -444,7 +466,7 @@ static bool mlx4_en_process_tx_cq(struct net_device *dev,
 				timestamp = mlx4_en_get_cqe_ts(cqe);
 
 			/* free next descriptor */
-			last_nr_txbb = mlx4_en_free_tx_desc(
+			last_nr_txbb = ring->free_tx_desc(
 					priv, ring, ring_index,
 					!!((ring_cons + txbbs_skipped) &
 					ring->size), timestamp, napi_budget);
@@ -476,6 +498,9 @@ static bool mlx4_en_process_tx_cq(struct net_device *dev,
 	ACCESS_ONCE(ring->last_nr_txbb) = last_nr_txbb;
 	ACCESS_ONCE(ring->cons) = ring_cons + txbbs_skipped;
 
+	if (ring->free_tx_desc == mlx4_en_recycle_tx_desc)
+		return done < budget;
+
 	netdev_tx_completed_queue(ring->tx_queue, packets, bytes);
 
 	/* Wakeup Tx queue if this stopped, and ring is not full.
@@ -631,8 +656,7 @@ static int get_real_size(const struct sk_buff *skb,
 static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc,
 			     const struct sk_buff *skb,
 			     const struct skb_shared_info *shinfo,
-			     int real_size, u16 *vlan_tag,
-			     int tx_ind, void *fragptr)
+			     void *fragptr)
 {
 	struct mlx4_wqe_inline_seg *inl = &tx_desc->inl;
 	int spc = MLX4_INLINE_ALIGN - CTRL_SIZE - sizeof *inl;
@@ -700,10 +724,66 @@ static void mlx4_bf_copy(void __iomem *dst, const void *src,
 	__iowrite64_copy(dst, src, bytecnt / 8);
 }
 
+void mlx4_en_xmit_doorbell(struct mlx4_en_tx_ring *ring)
+{
+	wmb();
+	/* Since there is no iowrite*_native() that writes the
+	 * value as is, without byteswapping - using the one
+	 * the doesn't do byteswapping in the relevant arch
+	 * endianness.
+	 */
+#if defined(__LITTLE_ENDIAN)
+	iowrite32(
+#else
+	iowrite32be(
+#endif
+		  ring->doorbell_qpn,
+		  ring->bf.uar->map + MLX4_SEND_DOORBELL);
+}
+
+static void mlx4_en_tx_write_desc(struct mlx4_en_tx_ring *ring,
+				  struct mlx4_en_tx_desc *tx_desc,
+				  union mlx4_wqe_qpn_vlan qpn_vlan,
+				  int desc_size, int bf_index,
+				  __be32 op_own, bool bf_ok,
+				  bool send_doorbell)
+{
+	tx_desc->ctrl.qpn_vlan = qpn_vlan;
+
+	if (bf_ok) {
+		op_own |= htonl((bf_index & 0xffff) << 8);
+		/* Ensure new descriptor hits memory
+		 * before setting ownership of this descriptor to HW
+		 */
+		dma_wmb();
+		tx_desc->ctrl.owner_opcode = op_own;
+
+		wmb();
+
+		mlx4_bf_copy(ring->bf.reg + ring->bf.offset, &tx_desc->ctrl,
+			     desc_size);
+
+		wmb();
+
+		ring->bf.offset ^= ring->bf.buf_size;
+	} else {
+		/* Ensure new descriptor hits memory
+		 * before setting ownership of this descriptor to HW
+		 */
+		dma_wmb();
+		tx_desc->ctrl.owner_opcode = op_own;
+		if (send_doorbell)
+			mlx4_en_xmit_doorbell(ring);
+		else
+			ring->xmit_more++;
+	}
+}
+
 netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct skb_shared_info *shinfo = skb_shinfo(skb);
 	struct mlx4_en_priv *priv = netdev_priv(dev);
+	union mlx4_wqe_qpn_vlan	qpn_vlan = {};
 	struct device *ddev = priv->ddev;
 	struct mlx4_en_tx_ring *ring;
 	struct mlx4_en_tx_desc *tx_desc;
@@ -715,7 +795,6 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
 	int real_size;
 	u32 index, bf_index;
 	__be32 op_own;
-	u16 vlan_tag = 0;
 	u16 vlan_proto = 0;
 	int i_frag;
 	int lso_header_size;
@@ -725,6 +804,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
 	bool stop_queue;
 	bool inline_ok;
 	u32 ring_cons;
+	bool bf_ok;
 
 	tx_ind = skb_get_queue_mapping(skb);
 	ring = priv->tx_ring[tx_ind];
@@ -749,9 +829,17 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
 		goto tx_drop;
 	}
 
+	bf_ok = ring->bf_enabled;
 	if (skb_vlan_tag_present(skb)) {
-		vlan_tag = skb_vlan_tag_get(skb);
+		qpn_vlan.vlan_tag = cpu_to_be16(skb_vlan_tag_get(skb));
 		vlan_proto = be16_to_cpu(skb->vlan_proto);
+		if (vlan_proto == ETH_P_8021AD)
+			qpn_vlan.ins_vlan = MLX4_WQE_CTRL_INS_SVLAN;
+		else if (vlan_proto == ETH_P_8021Q)
+			qpn_vlan.ins_vlan = MLX4_WQE_CTRL_INS_CVLAN;
+		else
+			qpn_vlan.ins_vlan = 0;
+		bf_ok = false;
 	}
 
 	netdev_txq_bql_enqueue_prefetchw(ring->tx_queue);
@@ -771,6 +859,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
 	else {
 		tx_desc = (struct mlx4_en_tx_desc *) ring->bounce_buf;
 		bounce = true;
+		bf_ok = false;
 	}
 
 	/* Save skb in tx_info ring */
@@ -907,8 +996,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
 	AVG_PERF_COUNTER(priv->pstats.tx_pktsz_avg, skb->len);
 
 	if (tx_info->inl)
-		build_inline_wqe(tx_desc, skb, shinfo, real_size, &vlan_tag,
-				 tx_ind, fragptr);
+		build_inline_wqe(tx_desc, skb, shinfo, fragptr);
 
 	if (skb->encapsulation) {
 		union {
@@ -946,60 +1034,15 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	real_size = (real_size / 16) & 0x3f;
 
-	if (ring->bf_enabled && desc_size <= MAX_BF && !bounce &&
-	    !skb_vlan_tag_present(skb) && send_doorbell) {
-		tx_desc->ctrl.bf_qpn = ring->doorbell_qpn |
-				       cpu_to_be32(real_size);
-
-		op_own |= htonl((bf_index & 0xffff) << 8);
-		/* Ensure new descriptor hits memory
-		 * before setting ownership of this descriptor to HW
-		 */
-		dma_wmb();
-		tx_desc->ctrl.owner_opcode = op_own;
-
-		wmb();
+	bf_ok &= desc_size <= MAX_BF && send_doorbell;
 
-		mlx4_bf_copy(ring->bf.reg + ring->bf.offset, &tx_desc->ctrl,
-			     desc_size);
-
-		wmb();
-
-		ring->bf.offset ^= ring->bf.buf_size;
-	} else {
-		tx_desc->ctrl.vlan_tag = cpu_to_be16(vlan_tag);
-		if (vlan_proto == ETH_P_8021AD)
-			tx_desc->ctrl.ins_vlan = MLX4_WQE_CTRL_INS_SVLAN;
-		else if (vlan_proto == ETH_P_8021Q)
-			tx_desc->ctrl.ins_vlan = MLX4_WQE_CTRL_INS_CVLAN;
-		else
-			tx_desc->ctrl.ins_vlan = 0;
-
-		tx_desc->ctrl.fence_size = real_size;
+	if (bf_ok)
+		qpn_vlan.bf_qpn = ring->doorbell_qpn | cpu_to_be32(real_size);
+	else
+		qpn_vlan.fence_size = real_size;
 
-		/* Ensure new descriptor hits memory
-		 * before setting ownership of this descriptor to HW
-		 */
-		dma_wmb();
-		tx_desc->ctrl.owner_opcode = op_own;
-		if (send_doorbell) {
-			wmb();
-			/* Since there is no iowrite*_native() that writes the
-			 * value as is, without byteswapping - using the one
-			 * the doesn't do byteswapping in the relevant arch
-			 * endianness.
-			 */
-#if defined(__LITTLE_ENDIAN)
-			iowrite32(
-#else
-			iowrite32be(
-#endif
-				  ring->doorbell_qpn,
-				  ring->bf.uar->map + MLX4_SEND_DOORBELL);
-		} else {
-			ring->xmit_more++;
-		}
-	}
+	mlx4_en_tx_write_desc(ring, tx_desc, qpn_vlan, desc_size, bf_index,
+			      op_own, bf_ok, send_doorbell);
 
 	if (unlikely(stop_queue)) {
 		/* If queue was emptied after the if (stop_queue) , and before
@@ -1034,3 +1077,106 @@ tx_drop:
 	return NETDEV_TX_OK;
 }
 
+netdev_tx_t mlx4_en_xmit_frame(struct mlx4_en_rx_alloc *frame,
+			       struct net_device *dev, unsigned int length,
+			       int tx_ind, int *doorbell_pending)
+{
+	struct mlx4_en_priv *priv = netdev_priv(dev);
+	union mlx4_wqe_qpn_vlan	qpn_vlan = {};
+	struct mlx4_en_tx_ring *ring;
+	struct mlx4_en_tx_desc *tx_desc;
+	struct mlx4_wqe_data_seg *data;
+	struct mlx4_en_tx_info *tx_info;
+	int index, bf_index;
+	bool send_doorbell;
+	int nr_txbb = 1;
+	bool stop_queue;
+	dma_addr_t dma;
+	int real_size;
+	__be32 op_own;
+	u32 ring_cons;
+	bool bf_ok;
+
+	BUILD_BUG_ON_MSG(ALIGN(CTRL_SIZE + DS_SIZE, TXBB_SIZE) != TXBB_SIZE,
+			 "mlx4_en_xmit_frame requires minimum size tx desc");
+
+	ring = priv->tx_ring[tx_ind];
+
+	if (!priv->port_up)
+		goto tx_drop;
+
+	if (mlx4_en_is_tx_ring_full(ring))
+		goto tx_drop;
+
+	/* fetch ring->cons far ahead before needing it to avoid stall */
+	ring_cons = READ_ONCE(ring->cons);
+
+	index = ring->prod & ring->size_mask;
+	tx_info = &ring->tx_info[index];
+
+	bf_ok = ring->bf_enabled;
+
+	/* Track current inflight packets for performance analysis */
+	AVG_PERF_COUNTER(priv->pstats.inflight_avg,
+			 (u32)(ring->prod - ring_cons - 1));
+
+	bf_index = ring->prod;
+	tx_desc = ring->buf + index * TXBB_SIZE;
+	data = &tx_desc->data;
+
+	dma = frame->dma;
+
+	tx_info->page = frame->page;
+	frame->page = NULL;
+	tx_info->map0_dma = dma;
+	tx_info->map0_byte_count = length;
+	tx_info->nr_txbb = nr_txbb;
+	tx_info->nr_bytes = max_t(unsigned int, length, ETH_ZLEN);
+	tx_info->data_offset = (void *)data - (void *)tx_desc;
+	tx_info->ts_requested = 0;
+	tx_info->nr_maps = 1;
+	tx_info->linear = 1;
+	tx_info->inl = 0;
+
+	dma_sync_single_for_device(priv->ddev, dma, length, PCI_DMA_TODEVICE);
+
+	data->addr = cpu_to_be64(dma);
+	data->lkey = ring->mr_key;
+	dma_wmb();
+	data->byte_count = cpu_to_be32(length);
+
+	/* tx completion can avoid cache line miss for common cases */
+	tx_desc->ctrl.srcrb_flags = priv->ctrl_flags;
+
+	op_own = cpu_to_be32(MLX4_OPCODE_SEND) |
+		((ring->prod & ring->size) ?
+		 cpu_to_be32(MLX4_EN_BIT_DESC_OWN) : 0);
+
+	ring->packets++;
+	ring->bytes += tx_info->nr_bytes;
+	AVG_PERF_COUNTER(priv->pstats.tx_pktsz_avg, length);
+
+	ring->prod += nr_txbb;
+
+	stop_queue = mlx4_en_is_tx_ring_full(ring);
+	send_doorbell = stop_queue ||
+				*doorbell_pending > MLX4_EN_DOORBELL_BUDGET;
+	bf_ok &= send_doorbell;
+
+	real_size = ((CTRL_SIZE + nr_txbb * DS_SIZE) / 16) & 0x3f;
+
+	if (bf_ok)
+		qpn_vlan.bf_qpn = ring->doorbell_qpn | cpu_to_be32(real_size);
+	else
+		qpn_vlan.fence_size = real_size;
+
+	mlx4_en_tx_write_desc(ring, tx_desc, qpn_vlan, TXBB_SIZE, bf_index,
+			      op_own, bf_ok, send_doorbell);
+	*doorbell_pending = send_doorbell ? 0 : *doorbell_pending + 1;
+
+	return NETDEV_TX_OK;
+
+tx_drop:
+	ring->tx_dropped++;
+	return NETDEV_TX_BUSY;
+}

drivers/net/ethernet/mellanox/mlx4/mlx4_en.h

@@ -132,6 +132,7 @@ enum {
 					 MLX4_EN_NUM_UP)
 
 #define MLX4_EN_DEFAULT_TX_WORK		256
+#define MLX4_EN_DOORBELL_BUDGET		8
 
 /* Target number of packets to coalesce with interrupt moderation */
 #define MLX4_EN_RX_COAL_TARGET	44
@@ -164,6 +165,10 @@ enum {
 #define MLX4_LOOPBACK_TEST_PAYLOAD (HEADER_COPY_SIZE - ETH_HLEN)
 
 #define MLX4_EN_MIN_MTU		46
+/* VLAN_HLEN is added twice,to support skb vlan tagged with multiple
+ * headers. (For example: ETH_P_8021Q and ETH_P_8021AD).
+ */
+#define MLX4_EN_EFF_MTU(mtu)	((mtu) + ETH_HLEN + (2 * VLAN_HLEN))
 #define ETH_BCAST		0xffffffffffffULL
 
 #define MLX4_EN_LOOPBACK_RETRIES	5
@@ -215,7 +220,10 @@ enum cq_type {
 
 
 struct mlx4_en_tx_info {
-	struct sk_buff *skb;
+	union {
+		struct sk_buff *skb;
+		struct page *page;
+	};
 	dma_addr_t	map0_dma;
 	u32		map0_byte_count;
 	u32		nr_txbb;
@@ -255,6 +263,14 @@ struct mlx4_en_rx_alloc {
 	u32		page_size;
 };
 
+#define MLX4_EN_CACHE_SIZE (2 * NAPI_POLL_WEIGHT)
+struct mlx4_en_page_cache {
+	u32 index;
+	struct mlx4_en_rx_alloc buf[MLX4_EN_CACHE_SIZE];
+};
+
+struct mlx4_en_priv;
+
 struct mlx4_en_tx_ring {
 	/* cache line used and dirtied in tx completion
 	 * (mlx4_en_free_tx_buf())
@@ -288,6 +304,11 @@ struct mlx4_en_tx_ring {
 	__be32			mr_key;
 	void			*buf;
 	struct mlx4_en_tx_info	*tx_info;
+	struct mlx4_en_rx_ring	*recycle_ring;
+	u32			(*free_tx_desc)(struct mlx4_en_priv *priv,
+						struct mlx4_en_tx_ring *ring,
+						int index, u8 owner,
+						u64 timestamp, int napi_mode);
 	u8			*bounce_buf;
 	struct mlx4_qp_context	context;
 	int			qpn;
@@ -319,6 +340,8 @@ struct mlx4_en_rx_ring {
 	u8  fcs_del;
 	void *buf;
 	void *rx_info;
+	struct bpf_prog *xdp_prog;
+	struct mlx4_en_page_cache page_cache;
 	unsigned long bytes;
 	unsigned long packets;
 	unsigned long csum_ok;
@@ -438,7 +461,9 @@ struct mlx4_en_mc_list {
 struct mlx4_en_frag_info {
 	u16 frag_size;
 	u16 frag_prefix_size;
-	u16 frag_stride;
+	u32 frag_stride;
+	enum dma_data_direction dma_dir;
+	int order;
 };
 
 #ifdef CONFIG_MLX4_EN_DCB
@@ -558,6 +583,7 @@ struct mlx4_en_priv {
 	struct mlx4_en_frag_info frag_info[MLX4_EN_MAX_RX_FRAGS];
 	u16 num_frags;
 	u16 log_rx_info;
+	int xdp_ring_num;
 
 	struct mlx4_en_tx_ring **tx_ring;
 	struct mlx4_en_rx_ring *rx_ring[MAX_RX_RINGS];
@@ -663,6 +689,12 @@ void mlx4_en_tx_irq(struct mlx4_cq *mcq);
 u16 mlx4_en_select_queue(struct net_device *dev, struct sk_buff *skb,
 			 void *accel_priv, select_queue_fallback_t fallback);
 netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev);
+netdev_tx_t mlx4_en_xmit_frame(struct mlx4_en_rx_alloc *frame,
+			       struct net_device *dev, unsigned int length,
+			       int tx_ind, int *doorbell_pending);
+void mlx4_en_xmit_doorbell(struct mlx4_en_tx_ring *ring);
+bool mlx4_en_rx_recycle(struct mlx4_en_rx_ring *ring,
+			struct mlx4_en_rx_alloc *frame);
 
 int mlx4_en_create_tx_ring(struct mlx4_en_priv *priv,
 			   struct mlx4_en_tx_ring **pring,
@@ -691,6 +723,14 @@ int mlx4_en_process_rx_cq(struct net_device *dev,
 			  int budget);
 int mlx4_en_poll_rx_cq(struct napi_struct *napi, int budget);
 int mlx4_en_poll_tx_cq(struct napi_struct *napi, int budget);
+u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv,
+			 struct mlx4_en_tx_ring *ring,
+			 int index, u8 owner, u64 timestamp,
+			 int napi_mode);
+u32 mlx4_en_recycle_tx_desc(struct mlx4_en_priv *priv,
+			    struct mlx4_en_tx_ring *ring,
+			    int index, u8 owner, u64 timestamp,
+			    int napi_mode);
 void mlx4_en_fill_qp_context(struct mlx4_en_priv *priv, int size, int stride,
 		int is_tx, int rss, int qpn, int cqn, int user_prio,
 		struct mlx4_qp_context *context);

include/linux/bpf.h

@@ -224,6 +224,7 @@ void bpf_register_map_type(struct bpf_map_type_list *tl);
 
 struct bpf_prog *bpf_prog_get(u32 ufd);
 struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type);
+struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i);
 struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog);
 void bpf_prog_put(struct bpf_prog *prog);
 

include/linux/filter.h

@@ -368,6 +368,11 @@ struct bpf_skb_data_end {
 	void *data_end;
 };
 
+struct xdp_buff {
+	void *data;
+	void *data_end;
+};
+
 /* compute the linear packet data range [data, data_end) which
  * will be accessed by cls_bpf and act_bpf programs
  */
@@ -429,6 +434,18 @@ static inline u32 bpf_prog_run_clear_cb(const struct bpf_prog *prog,
 	return BPF_PROG_RUN(prog, skb);
 }
 
+static inline u32 bpf_prog_run_xdp(const struct bpf_prog *prog,
+				   struct xdp_buff *xdp)
+{
+	u32 ret;
+
+	rcu_read_lock();
+	ret = BPF_PROG_RUN(prog, (void *)xdp);
+	rcu_read_unlock();
+
+	return ret;
+}
+
 static inline unsigned int bpf_prog_size(unsigned int proglen)
 {
 	return max(sizeof(struct bpf_prog),
@@ -509,6 +526,7 @@ bool bpf_helper_changes_skb_data(void *func);
 
 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
 				       const struct bpf_insn *patch, u32 len);
+void bpf_warn_invalid_xdp_action(u32 act);
 
 #ifdef CONFIG_BPF_JIT
 extern int bpf_jit_enable;

include/linux/mlx4/qp.h

@@ -291,16 +291,18 @@ enum {
 	MLX4_WQE_CTRL_FORCE_LOOPBACK	= 1 << 0,
 };
 
+union mlx4_wqe_qpn_vlan {
+	struct {
+		__be16	vlan_tag;
+		u8	ins_vlan;
+		u8	fence_size;
+	};
+	__be32		bf_qpn;
+};
+
 struct mlx4_wqe_ctrl_seg {
 	__be32			owner_opcode;
-	union {
-		struct {
-			__be16			vlan_tag;
-			u8			ins_vlan;
-			u8			fence_size;
-		};
-		__be32			bf_qpn;
-	};
+	union mlx4_wqe_qpn_vlan	qpn_vlan;
 	/*
 	 * High 24 bits are SRC remote buffer; low 8 bits are flags:
 	 * [7]   SO (strong ordering)

include/linux/netdevice.h

@@ -63,6 +63,7 @@ struct wpan_dev;
 struct mpls_dev;
 /* UDP Tunnel offloads */
 struct udp_tunnel_info;
+struct bpf_prog;
 
 void netdev_set_default_ethtool_ops(struct net_device *dev,
 				    const struct ethtool_ops *ops);
@@ -799,6 +800,33 @@ struct tc_to_netdev {
 	};
 };
 
+/* These structures hold the attributes of xdp state that are being passed
+ * to the netdevice through the xdp op.
+ */
+enum xdp_netdev_command {
+	/* Set or clear a bpf program used in the earliest stages of packet
+	 * rx. The prog will have been loaded as BPF_PROG_TYPE_XDP. The callee
+	 * is responsible for calling bpf_prog_put on any old progs that are
+	 * stored. In case of error, the callee need not release the new prog
+	 * reference, but on success it takes ownership and must bpf_prog_put
+	 * when it is no longer used.
+	 */
+	XDP_SETUP_PROG,
+	/* Check if a bpf program is set on the device.  The callee should
+	 * return true if a program is currently attached and running.
+	 */
+	XDP_QUERY_PROG,
+};
+
+struct netdev_xdp {
+	enum xdp_netdev_command command;
+	union {
+		/* XDP_SETUP_PROG */
+		struct bpf_prog *prog;
+		/* XDP_QUERY_PROG */
+		bool prog_attached;
+	};
+};
 
 /*
  * This structure defines the management hooks for network devices.
@@ -1087,6 +1115,9 @@ struct tc_to_netdev {
  *	appropriate rx headroom value allows avoiding skb head copy on
  *	forward. Setting a negative value resets the rx headroom to the
  *	default value.
+ * int (*ndo_xdp)(struct net_device *dev, struct netdev_xdp *xdp);
+ *	This function is used to set or query state related to XDP on the
+ *	netdevice. See definition of enum xdp_netdev_command for details.
  *
  */
 struct net_device_ops {
@@ -1271,6 +1302,8 @@ struct net_device_ops {
 						       struct sk_buff *skb);
 	void			(*ndo_set_rx_headroom)(struct net_device *dev,
 						       int needed_headroom);
+	int			(*ndo_xdp)(struct net_device *dev,
+					   struct netdev_xdp *xdp);
 };
 
 /**
@@ -3257,6 +3290,7 @@ int dev_get_phys_port_id(struct net_device *dev,
 int dev_get_phys_port_name(struct net_device *dev,
 			   char *name, size_t len);
 int dev_change_proto_down(struct net_device *dev, bool proto_down);
+int dev_change_xdp_fd(struct net_device *dev, int fd);
 struct sk_buff *validate_xmit_skb_list(struct sk_buff *skb, struct net_device *dev);
 struct sk_buff *dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
 				    struct netdev_queue *txq, int *ret);

include/uapi/linux/bpf.h

@@ -94,6 +94,7 @@ enum bpf_prog_type {
 	BPF_PROG_TYPE_SCHED_CLS,
 	BPF_PROG_TYPE_SCHED_ACT,
 	BPF_PROG_TYPE_TRACEPOINT,
+	BPF_PROG_TYPE_XDP,
 };
 
 #define BPF_PSEUDO_MAP_FD	1
@@ -439,4 +440,24 @@ struct bpf_tunnel_key {
 	__u32 tunnel_label;
 };
 
+/* User return codes for XDP prog type.
+ * A valid XDP program must return one of these defined values. All other
+ * return codes are reserved for future use. Unknown return codes will result
+ * in packet drop.
+ */
+enum xdp_action {
+	XDP_ABORTED = 0,
+	XDP_DROP,
+	XDP_PASS,
+	XDP_TX,
+};
+
+/* user accessible metadata for XDP packet hook
+ * new fields must be added to the end of this structure
+ */
+struct xdp_md {
+	__u32 data;
+	__u32 data_end;
+};
+
 #endif /* _UAPI__LINUX_BPF_H__ */

include/uapi/linux/if_link.h

@@ -156,6 +156,7 @@ enum {
 	IFLA_GSO_MAX_SEGS,
 	IFLA_GSO_MAX_SIZE,
 	IFLA_PAD,
+	IFLA_XDP,
 	__IFLA_MAX
 };
 
@@ -843,4 +844,15 @@ enum {
 };
 #define LINK_XSTATS_TYPE_MAX (__LINK_XSTATS_TYPE_MAX - 1)
 
+/* XDP section */
+
+enum {
+	IFLA_XDP_UNSPEC,
+	IFLA_XDP_FD,
+	IFLA_XDP_ATTACHED,
+	__IFLA_XDP_MAX,
+};
+
+#define IFLA_XDP_MAX (__IFLA_XDP_MAX - 1)
+
 #endif /* _UAPI_LINUX_IF_LINK_H */

kernel/bpf/syscall.c

@@ -670,14 +670,20 @@ static struct bpf_prog *____bpf_prog_get(struct fd f)
 	return f.file->private_data;
 }
 
-struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog)
+struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i)
 {
-	if (atomic_inc_return(&prog->aux->refcnt) > BPF_MAX_REFCNT) {
-		atomic_dec(&prog->aux->refcnt);
+	if (atomic_add_return(i, &prog->aux->refcnt) > BPF_MAX_REFCNT) {
+		atomic_sub(i, &prog->aux->refcnt);
 		return ERR_PTR(-EBUSY);
 	}
 	return prog;
 }
+EXPORT_SYMBOL_GPL(bpf_prog_add);
+
+struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog)
+{
+	return bpf_prog_add(prog, 1);
+}
 
 static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *type)
 {

kernel/bpf/verifier.c

@@ -653,6 +653,16 @@ static int check_map_access(struct verifier_env *env, u32 regno, int off,
 
 #define MAX_PACKET_OFF 0xffff
 
+static bool may_write_pkt_data(enum bpf_prog_type type)
+{
+	switch (type) {
+	case BPF_PROG_TYPE_XDP:
+		return true;
+	default:
+		return false;
+	}
+}
+
 static int check_packet_access(struct verifier_env *env, u32 regno, int off,
 			       int size)
 {
@@ -713,6 +723,7 @@ static int check_ptr_alignment(struct verifier_env *env, struct reg_state *reg,
 	switch (env->prog->type) {
 	case BPF_PROG_TYPE_SCHED_CLS:
 	case BPF_PROG_TYPE_SCHED_ACT:
+	case BPF_PROG_TYPE_XDP:
 		break;
 	default:
 		verbose("verifier is misconfigured\n");
@@ -805,10 +816,15 @@ static int check_mem_access(struct verifier_env *env, u32 regno, int off,
 			err = check_stack_read(state, off, size, value_regno);
 		}
 	} else if (state->regs[regno].type == PTR_TO_PACKET) {
-		if (t == BPF_WRITE) {
+		if (t == BPF_WRITE && !may_write_pkt_data(env->prog->type)) {
 			verbose("cannot write into packet\n");
 			return -EACCES;
 		}
+		if (t == BPF_WRITE && value_regno >= 0 &&
+		    is_pointer_value(env, value_regno)) {
+			verbose("R%d leaks addr into packet\n", value_regno);
+			return -EACCES;
+		}
 		err = check_packet_access(env, regno, off, size);
 		if (!err && t == BPF_READ && value_regno >= 0)
 			mark_reg_unknown_value(state->regs, value_regno);

net/core/dev.c

@@ -94,6 +94,7 @@
 #include <linux/ethtool.h>
 #include <linux/notifier.h>
 #include <linux/skbuff.h>
+#include <linux/bpf.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
 #include <net/busy_poll.h>
@@ -6614,6 +6615,38 @@ int dev_change_proto_down(struct net_device *dev, bool proto_down)
 }
 EXPORT_SYMBOL(dev_change_proto_down);
 
+/**
+ *	dev_change_xdp_fd - set or clear a bpf program for a device rx path
+ *	@dev: device
+ *	@fd: new program fd or negative value to clear
+ *
+ *	Set or clear a bpf program for a device
+ */
+int dev_change_xdp_fd(struct net_device *dev, int fd)
+{
+	const struct net_device_ops *ops = dev->netdev_ops;
+	struct bpf_prog *prog = NULL;
+	struct netdev_xdp xdp = {};
+	int err;
+
+	if (!ops->ndo_xdp)
+		return -EOPNOTSUPP;
+	if (fd >= 0) {
+		prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_XDP);
+		if (IS_ERR(prog))
+			return PTR_ERR(prog);
+	}
+
+	xdp.command = XDP_SETUP_PROG;
+	xdp.prog = prog;
+	err = ops->ndo_xdp(dev, &xdp);
+	if (err < 0 && prog)
+		bpf_prog_put(prog);
+
+	return err;
+}
+EXPORT_SYMBOL(dev_change_xdp_fd);
+
 /**
  *	dev_new_index	-	allocate an ifindex
  *	@net: the applicable net namespace

net/core/filter.c

@@ -2410,6 +2410,12 @@ tc_cls_act_func_proto(enum bpf_func_id func_id)
 	}
 }
 
+static const struct bpf_func_proto *
+xdp_func_proto(enum bpf_func_id func_id)
+{
+	return sk_filter_func_proto(func_id);
+}
+
 static bool __is_valid_access(int off, int size, enum bpf_access_type type)
 {
 	if (off < 0 || off >= sizeof(struct __sk_buff))
@@ -2477,6 +2483,44 @@ static bool tc_cls_act_is_valid_access(int off, int size,
 	return __is_valid_access(off, size, type);
 }
 
+static bool __is_valid_xdp_access(int off, int size,
+				  enum bpf_access_type type)
+{
+	if (off < 0 || off >= sizeof(struct xdp_md))
+		return false;
+	if (off % size != 0)
+		return false;
+	if (size != 4)
+		return false;
+
+	return true;
+}
+
+static bool xdp_is_valid_access(int off, int size,
+				enum bpf_access_type type,
+				enum bpf_reg_type *reg_type)
+{
+	if (type == BPF_WRITE)
+		return false;
+
+	switch (off) {
+	case offsetof(struct xdp_md, data):
+		*reg_type = PTR_TO_PACKET;
+		break;
+	case offsetof(struct xdp_md, data_end):
+		*reg_type = PTR_TO_PACKET_END;
+		break;
+	}
+
+	return __is_valid_xdp_access(off, size, type);
+}
+
+void bpf_warn_invalid_xdp_action(u32 act)
+{
+	WARN_ONCE(1, "Illegal XDP return value %u, expect packet loss\n", act);
+}
+EXPORT_SYMBOL_GPL(bpf_warn_invalid_xdp_action);
+
 static u32 bpf_net_convert_ctx_access(enum bpf_access_type type, int dst_reg,
 				      int src_reg, int ctx_off,
 				      struct bpf_insn *insn_buf,
@@ -2628,6 +2672,29 @@ static u32 bpf_net_convert_ctx_access(enum bpf_access_type type, int dst_reg,
 	return insn - insn_buf;
 }
 
+static u32 xdp_convert_ctx_access(enum bpf_access_type type, int dst_reg,
+				  int src_reg, int ctx_off,
+				  struct bpf_insn *insn_buf,
+				  struct bpf_prog *prog)
+{
+	struct bpf_insn *insn = insn_buf;
+
+	switch (ctx_off) {
+	case offsetof(struct xdp_md, data):
+		*insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct xdp_buff, data)),
+				      dst_reg, src_reg,
+				      offsetof(struct xdp_buff, data));
+		break;
+	case offsetof(struct xdp_md, data_end):
+		*insn++ = BPF_LDX_MEM(bytes_to_bpf_size(FIELD_SIZEOF(struct xdp_buff, data_end)),
+				      dst_reg, src_reg,
+				      offsetof(struct xdp_buff, data_end));
+		break;
+	}
+
+	return insn - insn_buf;
+}
+
 static const struct bpf_verifier_ops sk_filter_ops = {
 	.get_func_proto		= sk_filter_func_proto,
 	.is_valid_access	= sk_filter_is_valid_access,
@@ -2640,6 +2707,12 @@ static const struct bpf_verifier_ops tc_cls_act_ops = {
 	.convert_ctx_access	= bpf_net_convert_ctx_access,
 };
 
+static const struct bpf_verifier_ops xdp_ops = {
+	.get_func_proto		= xdp_func_proto,
+	.is_valid_access	= xdp_is_valid_access,
+	.convert_ctx_access	= xdp_convert_ctx_access,
+};
+
 static struct bpf_prog_type_list sk_filter_type __read_mostly = {
 	.ops	= &sk_filter_ops,
 	.type	= BPF_PROG_TYPE_SOCKET_FILTER,
@@ -2655,11 +2728,17 @@ static struct bpf_prog_type_list sched_act_type __read_mostly = {
 	.type	= BPF_PROG_TYPE_SCHED_ACT,
 };
 
+static struct bpf_prog_type_list xdp_type __read_mostly = {
+	.ops	= &xdp_ops,
+	.type	= BPF_PROG_TYPE_XDP,
+};
+
 static int __init register_sk_filter_ops(void)
 {
 	bpf_register_prog_type(&sk_filter_type);
 	bpf_register_prog_type(&sched_cls_type);
 	bpf_register_prog_type(&sched_act_type);
+	bpf_register_prog_type(&xdp_type);
 
 	return 0;
 }

net/core/rtnetlink.c

@@ -891,6 +891,16 @@ static size_t rtnl_port_size(const struct net_device *dev,
 		return port_self_size;
 }
 
+static size_t rtnl_xdp_size(const struct net_device *dev)
+{
+	size_t xdp_size = nla_total_size(1);	/* XDP_ATTACHED */
+
+	if (!dev->netdev_ops->ndo_xdp)
+		return 0;
+	else
+		return xdp_size;
+}
+
 static noinline size_t if_nlmsg_size(const struct net_device *dev,
 				     u32 ext_filter_mask)
 {
@@ -927,6 +937,7 @@ static noinline size_t if_nlmsg_size(const struct net_device *dev,
 	       + nla_total_size(MAX_PHYS_ITEM_ID_LEN) /* IFLA_PHYS_PORT_ID */
 	       + nla_total_size(MAX_PHYS_ITEM_ID_LEN) /* IFLA_PHYS_SWITCH_ID */
 	       + nla_total_size(IFNAMSIZ) /* IFLA_PHYS_PORT_NAME */
+	       + rtnl_xdp_size(dev) /* IFLA_XDP */
 	       + nla_total_size(1); /* IFLA_PROTO_DOWN */
 
 }
@@ -1211,6 +1222,33 @@ static int rtnl_fill_link_ifmap(struct sk_buff *skb, struct net_device *dev)
 	return 0;
 }
 
+static int rtnl_xdp_fill(struct sk_buff *skb, struct net_device *dev)
+{
+	struct netdev_xdp xdp_op = {};
+	struct nlattr *xdp;
+	int err;
+
+	if (!dev->netdev_ops->ndo_xdp)
+		return 0;
+	xdp = nla_nest_start(skb, IFLA_XDP);
+	if (!xdp)
+		return -EMSGSIZE;
+	xdp_op.command = XDP_QUERY_PROG;
+	err = dev->netdev_ops->ndo_xdp(dev, &xdp_op);
+	if (err)
+		goto err_cancel;
+	err = nla_put_u8(skb, IFLA_XDP_ATTACHED, xdp_op.prog_attached);
+	if (err)
+		goto err_cancel;
+
+	nla_nest_end(skb, xdp);
+	return 0;
+
+err_cancel:
+	nla_nest_cancel(skb, xdp);
+	return err;
+}
+
 static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
 			    int type, u32 pid, u32 seq, u32 change,
 			    unsigned int flags, u32 ext_filter_mask)
@@ -1307,6 +1345,9 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
 	if (rtnl_port_fill(skb, dev, ext_filter_mask))
 		goto nla_put_failure;
 
+	if (rtnl_xdp_fill(skb, dev))
+		goto nla_put_failure;
+
 	if (dev->rtnl_link_ops || rtnl_have_link_slave_info(dev)) {
 		if (rtnl_link_fill(skb, dev) < 0)
 			goto nla_put_failure;
@@ -1392,6 +1433,7 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
 	[IFLA_PHYS_SWITCH_ID]	= { .type = NLA_BINARY, .len = MAX_PHYS_ITEM_ID_LEN },
 	[IFLA_LINK_NETNSID]	= { .type = NLA_S32 },
 	[IFLA_PROTO_DOWN]	= { .type = NLA_U8 },
+	[IFLA_XDP]		= { .type = NLA_NESTED },
 };
 
 static const struct nla_policy ifla_info_policy[IFLA_INFO_MAX+1] = {
@@ -1429,6 +1471,11 @@ static const struct nla_policy ifla_port_policy[IFLA_PORT_MAX+1] = {
 	[IFLA_PORT_RESPONSE]	= { .type = NLA_U16, },
 };
 
+static const struct nla_policy ifla_xdp_policy[IFLA_XDP_MAX + 1] = {
+	[IFLA_XDP_FD]		= { .type = NLA_S32 },
+	[IFLA_XDP_ATTACHED]	= { .type = NLA_U8 },
+};
+
 static const struct rtnl_link_ops *linkinfo_to_kind_ops(const struct nlattr *nla)
 {
 	const struct rtnl_link_ops *ops = NULL;
@@ -2054,6 +2101,23 @@ static int do_setlink(const struct sk_buff *skb,
 		status |= DO_SETLINK_NOTIFY;
 	}
 
+	if (tb[IFLA_XDP]) {
+		struct nlattr *xdp[IFLA_XDP_MAX + 1];
+
+		err = nla_parse_nested(xdp, IFLA_XDP_MAX, tb[IFLA_XDP],
+				       ifla_xdp_policy);
+		if (err < 0)
+			goto errout;
+
+		if (xdp[IFLA_XDP_FD]) {
+			err = dev_change_xdp_fd(dev,
+						nla_get_s32(xdp[IFLA_XDP_FD]));
+			if (err)
+				goto errout;
+			status |= DO_SETLINK_NOTIFY;
+		}
+	}
+
 errout:
 	if (status & DO_SETLINK_MODIFIED) {
 		if (status & DO_SETLINK_NOTIFY)

samples/bpf/Makefile

@@ -21,6 +21,8 @@ hostprogs-y += spintest
 hostprogs-y += map_perf_test
 hostprogs-y += test_overhead
 hostprogs-y += test_cgrp2_array_pin
+hostprogs-y += xdp1
+hostprogs-y += xdp2
 
 test_verifier-objs := test_verifier.o libbpf.o
 test_maps-objs := test_maps.o libbpf.o
@@ -42,6 +44,9 @@ spintest-objs := bpf_load.o libbpf.o spintest_user.o
 map_perf_test-objs := bpf_load.o libbpf.o map_perf_test_user.o
 test_overhead-objs := bpf_load.o libbpf.o test_overhead_user.o
 test_cgrp2_array_pin-objs := libbpf.o test_cgrp2_array_pin.o
+xdp1-objs := bpf_load.o libbpf.o xdp1_user.o
+# reuse xdp1 source intentionally
+xdp2-objs := bpf_load.o libbpf.o xdp1_user.o
 
 # Tell kbuild to always build the programs
 always := $(hostprogs-y)
@@ -64,6 +69,8 @@ always += test_overhead_tp_kern.o
 always += test_overhead_kprobe_kern.o
 always += parse_varlen.o parse_simple.o parse_ldabs.o
 always += test_cgrp2_tc_kern.o
+always += xdp1_kern.o
+always += xdp2_kern.o
 
 HOSTCFLAGS += -I$(objtree)/usr/include
 
@@ -84,6 +91,8 @@ HOSTLOADLIBES_offwaketime += -lelf
 HOSTLOADLIBES_spintest += -lelf
 HOSTLOADLIBES_map_perf_test += -lelf -lrt
 HOSTLOADLIBES_test_overhead += -lelf -lrt
+HOSTLOADLIBES_xdp1 += -lelf
+HOSTLOADLIBES_xdp2 += -lelf
 
 # Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:
 #  make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang

samples/bpf/bpf_load.c

@@ -50,6 +50,7 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
 	bool is_kprobe = strncmp(event, "kprobe/", 7) == 0;
 	bool is_kretprobe = strncmp(event, "kretprobe/", 10) == 0;
 	bool is_tracepoint = strncmp(event, "tracepoint/", 11) == 0;
+	bool is_xdp = strncmp(event, "xdp", 3) == 0;
 	enum bpf_prog_type prog_type;
 	char buf[256];
 	int fd, efd, err, id;
@@ -66,6 +67,8 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
 		prog_type = BPF_PROG_TYPE_KPROBE;
 	} else if (is_tracepoint) {
 		prog_type = BPF_PROG_TYPE_TRACEPOINT;
+	} else if (is_xdp) {
+		prog_type = BPF_PROG_TYPE_XDP;
 	} else {
 		printf("Unknown event '%s'\n", event);
 		return -1;
@@ -79,6 +82,9 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
 
 	prog_fd[prog_cnt++] = fd;
 
+	if (is_xdp)
+		return 0;
+
 	if (is_socket) {
 		event += 6;
 		if (*event != '/')
@@ -319,6 +325,7 @@ int load_bpf_file(char *path)
 			if (memcmp(shname_prog, "kprobe/", 7) == 0 ||
 			    memcmp(shname_prog, "kretprobe/", 10) == 0 ||
 			    memcmp(shname_prog, "tracepoint/", 11) == 0 ||
+			    memcmp(shname_prog, "xdp", 3) == 0 ||
 			    memcmp(shname_prog, "socket", 6) == 0)
 				load_and_attach(shname_prog, insns, data_prog->d_size);
 		}
@@ -336,6 +343,7 @@ int load_bpf_file(char *path)
 		if (memcmp(shname, "kprobe/", 7) == 0 ||
 		    memcmp(shname, "kretprobe/", 10) == 0 ||
 		    memcmp(shname, "tracepoint/", 11) == 0 ||
+		    memcmp(shname, "xdp", 3) == 0 ||
 		    memcmp(shname, "socket", 6) == 0)
 			load_and_attach(shname, data->d_buf, data->d_size);
 	}

samples/bpf/xdp1_kern.c

@@ -0,0 +1,93 @@
+/* Copyright (c) 2016 PLUMgrid
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#define KBUILD_MODNAME "foo"
+#include <uapi/linux/bpf.h>
+#include <linux/in.h>
+#include <linux/if_ether.h>
+#include <linux/if_packet.h>
+#include <linux/if_vlan.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include "bpf_helpers.h"
+
+struct bpf_map_def SEC("maps") dropcnt = {
+	.type = BPF_MAP_TYPE_PERCPU_ARRAY,
+	.key_size = sizeof(u32),
+	.value_size = sizeof(long),
+	.max_entries = 256,
+};
+
+static int parse_ipv4(void *data, u64 nh_off, void *data_end)
+{
+	struct iphdr *iph = data + nh_off;
+
+	if (iph + 1 > data_end)
+		return 0;
+	return iph->protocol;
+}
+
+static int parse_ipv6(void *data, u64 nh_off, void *data_end)
+{
+	struct ipv6hdr *ip6h = data + nh_off;
+
+	if (ip6h + 1 > data_end)
+		return 0;
+	return ip6h->nexthdr;
+}
+
+SEC("xdp1")
+int xdp_prog1(struct xdp_md *ctx)
+{
+	void *data_end = (void *)(long)ctx->data_end;
+	void *data = (void *)(long)ctx->data;
+	struct ethhdr *eth = data;
+	int rc = XDP_DROP;
+	long *value;
+	u16 h_proto;
+	u64 nh_off;
+	u32 index;
+
+	nh_off = sizeof(*eth);
+	if (data + nh_off > data_end)
+		return rc;
+
+	h_proto = eth->h_proto;
+
+	if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
+		struct vlan_hdr *vhdr;
+
+		vhdr = data + nh_off;
+		nh_off += sizeof(struct vlan_hdr);
+		if (data + nh_off > data_end)
+			return rc;
+		h_proto = vhdr->h_vlan_encapsulated_proto;
+	}
+	if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
+		struct vlan_hdr *vhdr;
+
+		vhdr = data + nh_off;
+		nh_off += sizeof(struct vlan_hdr);
+		if (data + nh_off > data_end)
+			return rc;
+		h_proto = vhdr->h_vlan_encapsulated_proto;
+	}
+
+	if (h_proto == htons(ETH_P_IP))
+		index = parse_ipv4(data, nh_off, data_end);
+	else if (h_proto == htons(ETH_P_IPV6))
+		index = parse_ipv6(data, nh_off, data_end);
+	else
+		index = 0;
+
+	value = bpf_map_lookup_elem(&dropcnt, &index);
+	if (value)
+		*value += 1;
+
+	return rc;
+}
+
+char _license[] SEC("license") = "GPL";

samples/bpf/xdp1_user.c

@@ -0,0 +1,181 @@
+/* Copyright (c) 2016 PLUMgrid
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#include <linux/bpf.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <assert.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include "bpf_load.h"
+#include "libbpf.h"
+
+static int set_link_xdp_fd(int ifindex, int fd)
+{
+	struct sockaddr_nl sa;
+	int sock, seq = 0, len, ret = -1;
+	char buf[4096];
+	struct nlattr *nla, *nla_xdp;
+	struct {
+		struct nlmsghdr  nh;
+		struct ifinfomsg ifinfo;
+		char             attrbuf[64];
+	} req;
+	struct nlmsghdr *nh;
+	struct nlmsgerr *err;
+
+	memset(&sa, 0, sizeof(sa));
+	sa.nl_family = AF_NETLINK;
+
+	sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
+	if (sock < 0) {
+		printf("open netlink socket: %s\n", strerror(errno));
+		return -1;
+	}
+
+	if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
+		printf("bind to netlink: %s\n", strerror(errno));
+		goto cleanup;
+	}
+
+	memset(&req, 0, sizeof(req));
+	req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
+	req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
+	req.nh.nlmsg_type = RTM_SETLINK;
+	req.nh.nlmsg_pid = 0;
+	req.nh.nlmsg_seq = ++seq;
+	req.ifinfo.ifi_family = AF_UNSPEC;
+	req.ifinfo.ifi_index = ifindex;
+	nla = (struct nlattr *)(((char *)&req)
+				+ NLMSG_ALIGN(req.nh.nlmsg_len));
+	nla->nla_type = NLA_F_NESTED | 43/*IFLA_XDP*/;
+
+	nla_xdp = (struct nlattr *)((char *)nla + NLA_HDRLEN);
+	nla_xdp->nla_type = 1/*IFLA_XDP_FD*/;
+	nla_xdp->nla_len = NLA_HDRLEN + sizeof(int);
+	memcpy((char *)nla_xdp + NLA_HDRLEN, &fd, sizeof(fd));
+	nla->nla_len = NLA_HDRLEN + nla_xdp->nla_len;
+
+	req.nh.nlmsg_len += NLA_ALIGN(nla->nla_len);
+
+	if (send(sock, &req, req.nh.nlmsg_len, 0) < 0) {
+		printf("send to netlink: %s\n", strerror(errno));
+		goto cleanup;
+	}
+
+	len = recv(sock, buf, sizeof(buf), 0);
+	if (len < 0) {
+		printf("recv from netlink: %s\n", strerror(errno));
+		goto cleanup;
+	}
+
+	for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len);
+	     nh = NLMSG_NEXT(nh, len)) {
+		if (nh->nlmsg_pid != getpid()) {
+			printf("Wrong pid %d, expected %d\n",
+			       nh->nlmsg_pid, getpid());
+			goto cleanup;
+		}
+		if (nh->nlmsg_seq != seq) {
+			printf("Wrong seq %d, expected %d\n",
+			       nh->nlmsg_seq, seq);
+			goto cleanup;
+		}
+		switch (nh->nlmsg_type) {
+		case NLMSG_ERROR:
+			err = (struct nlmsgerr *)NLMSG_DATA(nh);
+			if (!err->error)
+				continue;
+			printf("nlmsg error %s\n", strerror(-err->error));
+			goto cleanup;
+		case NLMSG_DONE:
+			break;
+		}
+	}
+
+	ret = 0;
+
+cleanup:
+	close(sock);
+	return ret;
+}
+
+static int ifindex;
+
+static void int_exit(int sig)
+{
+	set_link_xdp_fd(ifindex, -1);
+	exit(0);
+}
+
+/* simple per-protocol drop counter
+ */
+static void poll_stats(int interval)
+{
+	unsigned int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
+	const unsigned int nr_keys = 256;
+	__u64 values[nr_cpus], prev[nr_keys][nr_cpus];
+	__u32 key;
+	int i;
+
+	memset(prev, 0, sizeof(prev));
+
+	while (1) {
+		sleep(interval);
+
+		for (key = 0; key < nr_keys; key++) {
+			__u64 sum = 0;
+
+			assert(bpf_lookup_elem(map_fd[0], &key, values) == 0);
+			for (i = 0; i < nr_cpus; i++)
+				sum += (values[i] - prev[key][i]);
+			if (sum)
+				printf("proto %u: %10llu pkt/s\n",
+				       key, sum / interval);
+			memcpy(prev[key], values, sizeof(values));
+		}
+	}
+}
+
+int main(int ac, char **argv)
+{
+	char filename[256];
+
+	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+
+	if (ac != 2) {
+		printf("usage: %s IFINDEX\n", argv[0]);
+		return 1;
+	}
+
+	ifindex = strtoul(argv[1], NULL, 0);
+
+	if (load_bpf_file(filename)) {
+		printf("%s", bpf_log_buf);
+		return 1;
+	}
+
+	if (!prog_fd[0]) {
+		printf("load_bpf_file: %s\n", strerror(errno));
+		return 1;
+	}
+
+	signal(SIGINT, int_exit);
+
+	if (set_link_xdp_fd(ifindex, prog_fd[0]) < 0) {
+		printf("link set xdp fd failed\n");
+		return 1;
+	}
+
+	poll_stats(2);
+
+	return 0;
+}

samples/bpf/xdp2_kern.c

@@ -0,0 +1,114 @@
+/* Copyright (c) 2016 PLUMgrid
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#define KBUILD_MODNAME "foo"
+#include <uapi/linux/bpf.h>
+#include <linux/in.h>
+#include <linux/if_ether.h>
+#include <linux/if_packet.h>
+#include <linux/if_vlan.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include "bpf_helpers.h"
+
+struct bpf_map_def SEC("maps") dropcnt = {
+	.type = BPF_MAP_TYPE_PERCPU_ARRAY,
+	.key_size = sizeof(u32),
+	.value_size = sizeof(long),
+	.max_entries = 256,
+};
+
+static void swap_src_dst_mac(void *data)
+{
+	unsigned short *p = data;
+	unsigned short dst[3];
+
+	dst[0] = p[0];
+	dst[1] = p[1];
+	dst[2] = p[2];
+	p[0] = p[3];
+	p[1] = p[4];
+	p[2] = p[5];
+	p[3] = dst[0];
+	p[4] = dst[1];
+	p[5] = dst[2];
+}
+
+static int parse_ipv4(void *data, u64 nh_off, void *data_end)
+{
+	struct iphdr *iph = data + nh_off;
+
+	if (iph + 1 > data_end)
+		return 0;
+	return iph->protocol;
+}
+
+static int parse_ipv6(void *data, u64 nh_off, void *data_end)
+{
+	struct ipv6hdr *ip6h = data + nh_off;
+
+	if (ip6h + 1 > data_end)
+		return 0;
+	return ip6h->nexthdr;
+}
+
+SEC("xdp1")
+int xdp_prog1(struct xdp_md *ctx)
+{
+	void *data_end = (void *)(long)ctx->data_end;
+	void *data = (void *)(long)ctx->data;
+	struct ethhdr *eth = data;
+	int rc = XDP_DROP;
+	long *value;
+	u16 h_proto;
+	u64 nh_off;
+	u32 index;
+
+	nh_off = sizeof(*eth);
+	if (data + nh_off > data_end)
+		return rc;
+
+	h_proto = eth->h_proto;
+
+	if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
+		struct vlan_hdr *vhdr;
+
+		vhdr = data + nh_off;
+		nh_off += sizeof(struct vlan_hdr);
+		if (data + nh_off > data_end)
+			return rc;
+		h_proto = vhdr->h_vlan_encapsulated_proto;
+	}
+	if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
+		struct vlan_hdr *vhdr;
+
+		vhdr = data + nh_off;
+		nh_off += sizeof(struct vlan_hdr);
+		if (data + nh_off > data_end)
+			return rc;
+		h_proto = vhdr->h_vlan_encapsulated_proto;
+	}
+
+	if (h_proto == htons(ETH_P_IP))
+		index = parse_ipv4(data, nh_off, data_end);
+	else if (h_proto == htons(ETH_P_IPV6))
+		index = parse_ipv6(data, nh_off, data_end);
+	else
+		index = 0;
+
+	value = bpf_map_lookup_elem(&dropcnt, &index);
+	if (value)
+		*value += 1;
+
+	if (index == 17) {
+		swap_src_dst_mac(data);
+		rc = XDP_TX;
+	}
+
+	return rc;
+}
+
+char _license[] SEC("license") = "GPL";