LXR linux/drivers/net/ethernet/microsoft/mana/mana

   1// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
   2/* Copyright (c) 2021, Microsoft Corporation. */
   3
   4#include <linux/inetdevice.h>
   5#include <linux/etherdevice.h>
   6#include <linux/mm.h>
   7#include <linux/bpf.h>
   8#include <linux/bpf_trace.h>
   9#include <net/xdp.h>
  10
  11#include "mana.h"
  12
  13void mana_xdp_tx(struct sk_buff *skb, struct net_device *ndev)
  14{
  15        u16 txq_idx = skb_get_queue_mapping(skb);
  16        struct netdev_queue *ndevtxq;
  17        int rc;
  18
  19        __skb_push(skb, ETH_HLEN);
  20
  21        ndevtxq = netdev_get_tx_queue(ndev, txq_idx);
  22        __netif_tx_lock(ndevtxq, smp_processor_id());
  23
  24        rc = mana_start_xmit(skb, ndev);
  25
  26        __netif_tx_unlock(ndevtxq);
  27
  28        if (dev_xmit_complete(rc))
  29                return;
  30
  31        dev_kfree_skb_any(skb);
  32        ndev->stats.tx_dropped++;
  33}
  34
  35u32 mana_run_xdp(struct net_device *ndev, struct mana_rxq *rxq,
  36                 struct xdp_buff *xdp, void *buf_va, uint pkt_len)
  37{
  38        struct bpf_prog *prog;
  39        u32 act = XDP_PASS;
  40
  41        rcu_read_lock();
  42        prog = rcu_dereference(rxq->bpf_prog);
  43
  44        if (!prog)
  45                goto out;
  46
  47        xdp_init_buff(xdp, PAGE_SIZE, &rxq->xdp_rxq);
  48        xdp_prepare_buff(xdp, buf_va, XDP_PACKET_HEADROOM, pkt_len, false);
  49
  50        act = bpf_prog_run_xdp(prog, xdp);
  51
  52        switch (act) {
  53        case XDP_PASS:
  54        case XDP_TX:
  55        case XDP_DROP:
  56                break;
  57
  58        case XDP_ABORTED:
  59                trace_xdp_exception(ndev, prog, act);
  60                break;
  61
  62        default:
  63                bpf_warn_invalid_xdp_action(ndev, prog, act);
  64        }
  65
  66out:
  67        rcu_read_unlock();
  68
  69        return act;
  70}
  71
  72static unsigned int mana_xdp_fraglen(unsigned int len)
  73{
  74        return SKB_DATA_ALIGN(len) +
  75               SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
  76}
  77
  78struct bpf_prog *mana_xdp_get(struct mana_port_context *apc)
  79{
  80        ASSERT_RTNL();
  81
  82        return apc->bpf_prog;
  83}
  84
  85static struct bpf_prog *mana_chn_xdp_get(struct mana_port_context *apc)
  86{
  87        return rtnl_dereference(apc->rxqs[0]->bpf_prog);
  88}
  89
  90/* Set xdp program on channels */
  91void mana_chn_setxdp(struct mana_port_context *apc, struct bpf_prog *prog)
  92{
  93        struct bpf_prog *old_prog = mana_chn_xdp_get(apc);
  94        unsigned int num_queues = apc->num_queues;
  95        int i;
  96
  97        ASSERT_RTNL();
  98
  99        if (old_prog == prog)
 100                return;
 101
 102        if (prog)
 103                bpf_prog_add(prog, num_queues);
 104
 105        for (i = 0; i < num_queues; i++)
 106                rcu_assign_pointer(apc->rxqs[i]->bpf_prog, prog);
 107
 108        if (old_prog)
 109                for (i = 0; i < num_queues; i++)
 110                        bpf_prog_put(old_prog);
 111}
 112
 113static int mana_xdp_set(struct net_device *ndev, struct bpf_prog *prog,
 114                        struct netlink_ext_ack *extack)
 115{
 116        struct mana_port_context *apc = netdev_priv(ndev);
 117        struct bpf_prog *old_prog;
 118        int buf_max;
 119
 120        old_prog = mana_xdp_get(apc);
 121
 122        if (!old_prog && !prog)
 123                return 0;
 124
 125        buf_max = XDP_PACKET_HEADROOM + mana_xdp_fraglen(ndev->mtu + ETH_HLEN);
 126        if (prog && buf_max > PAGE_SIZE) {
 127                netdev_err(ndev, "XDP: mtu:%u too large, buf_max:%u\n",
 128                           ndev->mtu, buf_max);
 129                NL_SET_ERR_MSG_MOD(extack, "XDP: mtu too large");
 130
 131                return -EOPNOTSUPP;
 132        }
 133
 134        /* One refcnt of the prog is hold by the caller already, so
 135         * don't increase refcnt for this one.
 136         */
 137        apc->bpf_prog = prog;
 138
 139        if (old_prog)
 140                bpf_prog_put(old_prog);
 141
 142        if (apc->port_is_up)
 143                mana_chn_setxdp(apc, prog);
 144
 145        return 0;
 146}
 147
 148int mana_bpf(struct net_device *ndev, struct netdev_bpf *bpf)
 149{
 150        struct netlink_ext_ack *extack = bpf->extack;
 151        int ret;
 152
 153        switch (bpf->command) {
 154        case XDP_SETUP_PROG:
 155                return mana_xdp_set(ndev, bpf->prog, extack);
 156
 157        default:
 158                return -EOPNOTSUPP;
 159        }
 160
 161        return ret;
 162}
 163