net: mana: Add XDP support

Add support of XDP for the MANA driver.

Supported XDP actions:
	XDP_PASS, XDP_TX, XDP_DROP, XDP_ABORTED

XDP actions not yet supported:
	XDP_REDIRECT

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 162 insertions, 0 deletions

diff --git a/drivers/net/ethernet/microsoft/mana/mana_bpf.c b/drivers/net/ethernet/microsoft/mana/mana_bpf.c
new file mode 100644
index 000000000000..1bc8ff388341
--- /dev/null
+++ b/drivers/net/ethernet/microsoft/mana/mana_bpf.c
@@ -0,0 +1,162 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+/* Copyright (c) 2021, Microsoft Corporation. */
+
+#include <linux/inetdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/mm.h>
+#include <linux/bpf.h>
+#include <linux/bpf_trace.h>
+#include <net/xdp.h>
+
+#include "mana.h"
+
+void mana_xdp_tx(struct sk_buff *skb, struct net_device *ndev)
+{
+	u16 txq_idx = skb_get_queue_mapping(skb);
+	struct netdev_queue *ndevtxq;
+	int rc;
+
+	__skb_push(skb, ETH_HLEN);
+
+	ndevtxq = netdev_get_tx_queue(ndev, txq_idx);
+	__netif_tx_lock(ndevtxq, smp_processor_id());
+
+	rc = mana_start_xmit(skb, ndev);
+
+	__netif_tx_unlock(ndevtxq);
+
+	if (dev_xmit_complete(rc))
+		return;
+
+	dev_kfree_skb_any(skb);
+	ndev->stats.tx_dropped++;
+}
+
+u32 mana_run_xdp(struct net_device *ndev, struct mana_rxq *rxq,
+		 struct xdp_buff *xdp, void *buf_va, uint pkt_len)
+{
+	struct bpf_prog *prog;
+	u32 act = XDP_PASS;
+
+	rcu_read_lock();
+	prog = rcu_dereference(rxq->bpf_prog);
+
+	if (!prog)
+		goto out;
+
+	xdp_init_buff(xdp, PAGE_SIZE, &rxq->xdp_rxq);
+	xdp_prepare_buff(xdp, buf_va, XDP_PACKET_HEADROOM, pkt_len, false);
+
+	act = bpf_prog_run_xdp(prog, xdp);
+
+	switch (act) {
+	case XDP_PASS:
+	case XDP_TX:
+	case XDP_DROP:
+		break;
+
+	case XDP_ABORTED:
+		trace_xdp_exception(ndev, prog, act);
+		break;
+
+	default:
+		bpf_warn_invalid_xdp_action(act);
+	}
+
+out:
+	rcu_read_unlock();
+
+	return act;
+}
+
+static unsigned int mana_xdp_fraglen(unsigned int len)
+{
+	return SKB_DATA_ALIGN(len) +
+	       SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+}
+
+struct bpf_prog *mana_xdp_get(struct mana_port_context *apc)
+{
+	ASSERT_RTNL();
+
+	return apc->bpf_prog;
+}
+
+static struct bpf_prog *mana_chn_xdp_get(struct mana_port_context *apc)
+{
+	return rtnl_dereference(apc->rxqs[0]->bpf_prog);
+}
+
+/* Set xdp program on channels */
+void mana_chn_setxdp(struct mana_port_context *apc, struct bpf_prog *prog)
+{
+	struct bpf_prog *old_prog = mana_chn_xdp_get(apc);
+	unsigned int num_queues = apc->num_queues;
+	int i;
+
+	ASSERT_RTNL();
+
+	if (old_prog == prog)
+		return;
+
+	if (prog)
+		bpf_prog_add(prog, num_queues);
+
+	for (i = 0; i < num_queues; i++)
+		rcu_assign_pointer(apc->rxqs[i]->bpf_prog, prog);
+
+	if (old_prog)
+		for (i = 0; i < num_queues; i++)
+			bpf_prog_put(old_prog);
+}
+
+static int mana_xdp_set(struct net_device *ndev, struct bpf_prog *prog,
+			struct netlink_ext_ack *extack)
+{
+	struct mana_port_context *apc = netdev_priv(ndev);
+	struct bpf_prog *old_prog;
+	int buf_max;
+
+	old_prog = mana_xdp_get(apc);
+
+	if (!old_prog && !prog)
+		return 0;
+
+	buf_max = XDP_PACKET_HEADROOM + mana_xdp_fraglen(ndev->mtu + ETH_HLEN);
+	if (prog && buf_max > PAGE_SIZE) {
+		netdev_err(ndev, "XDP: mtu:%u too large, buf_max:%u\n",
+			   ndev->mtu, buf_max);
+		NL_SET_ERR_MSG_MOD(extack, "XDP: mtu too large");
+
+		return -EOPNOTSUPP;
+	}
+
+	/* One refcnt of the prog is hold by the caller already, so
+	 * don't increase refcnt for this one.
+	 */
+	apc->bpf_prog = prog;
+
+	if (old_prog)
+		bpf_prog_put(old_prog);
+
+	if (apc->port_is_up)
+		mana_chn_setxdp(apc, prog);
+
+	return 0;
+}
+
+int mana_bpf(struct net_device *ndev, struct netdev_bpf *bpf)
+{
+	struct netlink_ext_ack *extack = bpf->extack;
+	int ret;
+
+	switch (bpf->command) {
+	case XDP_SETUP_PROG:
+		return mana_xdp_set(ndev, bpf->prog, extack);
+
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return ret;
+}