cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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mana_bpf.c (3272B)

      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}