cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

interface.c (22511B)


      1/*
      2 * Network-device interface management.
      3 *
      4 * Copyright (c) 2004-2005, Keir Fraser
      5 *
      6 * This program is free software; you can redistribute it and/or
      7 * modify it under the terms of the GNU General Public License version 2
      8 * as published by the Free Software Foundation; or, when distributed
      9 * separately from the Linux kernel or incorporated into other
     10 * software packages, subject to the following license:
     11 *
     12 * Permission is hereby granted, free of charge, to any person obtaining a copy
     13 * of this source file (the "Software"), to deal in the Software without
     14 * restriction, including without limitation the rights to use, copy, modify,
     15 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
     16 * and to permit persons to whom the Software is furnished to do so, subject to
     17 * the following conditions:
     18 *
     19 * The above copyright notice and this permission notice shall be included in
     20 * all copies or substantial portions of the Software.
     21 *
     22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     23 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     24 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
     25 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     26 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     27 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
     28 * IN THE SOFTWARE.
     29 */
     30
     31#include "common.h"
     32
     33#include <linux/kthread.h>
     34#include <linux/sched/task.h>
     35#include <linux/ethtool.h>
     36#include <linux/rtnetlink.h>
     37#include <linux/if_vlan.h>
     38#include <linux/vmalloc.h>
     39
     40#include <xen/events.h>
     41#include <asm/xen/hypercall.h>
     42#include <xen/balloon.h>
     43
     44#define XENVIF_QUEUE_LENGTH 32
     45
     46/* Number of bytes allowed on the internal guest Rx queue. */
     47#define XENVIF_RX_QUEUE_BYTES (XEN_NETIF_RX_RING_SIZE/2 * PAGE_SIZE)
     48
     49/* This function is used to set SKBFL_ZEROCOPY_ENABLE as well as
     50 * increasing the inflight counter. We need to increase the inflight
     51 * counter because core driver calls into xenvif_zerocopy_callback
     52 * which calls xenvif_skb_zerocopy_complete.
     53 */
     54void xenvif_skb_zerocopy_prepare(struct xenvif_queue *queue,
     55				 struct sk_buff *skb)
     56{
     57	skb_shinfo(skb)->flags |= SKBFL_ZEROCOPY_ENABLE;
     58	atomic_inc(&queue->inflight_packets);
     59}
     60
     61void xenvif_skb_zerocopy_complete(struct xenvif_queue *queue)
     62{
     63	atomic_dec(&queue->inflight_packets);
     64
     65	/* Wake the dealloc thread _after_ decrementing inflight_packets so
     66	 * that if kthread_stop() has already been called, the dealloc thread
     67	 * does not wait forever with nothing to wake it.
     68	 */
     69	wake_up(&queue->dealloc_wq);
     70}
     71
     72int xenvif_schedulable(struct xenvif *vif)
     73{
     74	return netif_running(vif->dev) &&
     75		test_bit(VIF_STATUS_CONNECTED, &vif->status) &&
     76		!vif->disabled;
     77}
     78
     79static bool xenvif_handle_tx_interrupt(struct xenvif_queue *queue)
     80{
     81	bool rc;
     82
     83	rc = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx);
     84	if (rc)
     85		napi_schedule(&queue->napi);
     86	return rc;
     87}
     88
     89static irqreturn_t xenvif_tx_interrupt(int irq, void *dev_id)
     90{
     91	struct xenvif_queue *queue = dev_id;
     92	int old;
     93
     94	old = atomic_fetch_or(NETBK_TX_EOI, &queue->eoi_pending);
     95	WARN(old & NETBK_TX_EOI, "Interrupt while EOI pending\n");
     96
     97	if (!xenvif_handle_tx_interrupt(queue)) {
     98		atomic_andnot(NETBK_TX_EOI, &queue->eoi_pending);
     99		xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS);
    100	}
    101
    102	return IRQ_HANDLED;
    103}
    104
    105static int xenvif_poll(struct napi_struct *napi, int budget)
    106{
    107	struct xenvif_queue *queue =
    108		container_of(napi, struct xenvif_queue, napi);
    109	int work_done;
    110
    111	/* This vif is rogue, we pretend we've there is nothing to do
    112	 * for this vif to deschedule it from NAPI. But this interface
    113	 * will be turned off in thread context later.
    114	 */
    115	if (unlikely(queue->vif->disabled)) {
    116		napi_complete(napi);
    117		return 0;
    118	}
    119
    120	work_done = xenvif_tx_action(queue, budget);
    121
    122	if (work_done < budget) {
    123		napi_complete_done(napi, work_done);
    124		/* If the queue is rate-limited, it shall be
    125		 * rescheduled in the timer callback.
    126		 */
    127		if (likely(!queue->rate_limited))
    128			xenvif_napi_schedule_or_enable_events(queue);
    129	}
    130
    131	return work_done;
    132}
    133
    134static bool xenvif_handle_rx_interrupt(struct xenvif_queue *queue)
    135{
    136	bool rc;
    137
    138	rc = xenvif_have_rx_work(queue, false);
    139	if (rc)
    140		xenvif_kick_thread(queue);
    141	return rc;
    142}
    143
    144static irqreturn_t xenvif_rx_interrupt(int irq, void *dev_id)
    145{
    146	struct xenvif_queue *queue = dev_id;
    147	int old;
    148
    149	old = atomic_fetch_or(NETBK_RX_EOI, &queue->eoi_pending);
    150	WARN(old & NETBK_RX_EOI, "Interrupt while EOI pending\n");
    151
    152	if (!xenvif_handle_rx_interrupt(queue)) {
    153		atomic_andnot(NETBK_RX_EOI, &queue->eoi_pending);
    154		xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS);
    155	}
    156
    157	return IRQ_HANDLED;
    158}
    159
    160irqreturn_t xenvif_interrupt(int irq, void *dev_id)
    161{
    162	struct xenvif_queue *queue = dev_id;
    163	int old;
    164	bool has_rx, has_tx;
    165
    166	old = atomic_fetch_or(NETBK_COMMON_EOI, &queue->eoi_pending);
    167	WARN(old, "Interrupt while EOI pending\n");
    168
    169	has_tx = xenvif_handle_tx_interrupt(queue);
    170	has_rx = xenvif_handle_rx_interrupt(queue);
    171
    172	if (!has_rx && !has_tx) {
    173		atomic_andnot(NETBK_COMMON_EOI, &queue->eoi_pending);
    174		xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS);
    175	}
    176
    177	return IRQ_HANDLED;
    178}
    179
    180int xenvif_queue_stopped(struct xenvif_queue *queue)
    181{
    182	struct net_device *dev = queue->vif->dev;
    183	unsigned int id = queue->id;
    184	return netif_tx_queue_stopped(netdev_get_tx_queue(dev, id));
    185}
    186
    187void xenvif_wake_queue(struct xenvif_queue *queue)
    188{
    189	struct net_device *dev = queue->vif->dev;
    190	unsigned int id = queue->id;
    191	netif_tx_wake_queue(netdev_get_tx_queue(dev, id));
    192}
    193
    194static u16 xenvif_select_queue(struct net_device *dev, struct sk_buff *skb,
    195			       struct net_device *sb_dev)
    196{
    197	struct xenvif *vif = netdev_priv(dev);
    198	unsigned int size = vif->hash.size;
    199	unsigned int num_queues;
    200
    201	/* If queues are not set up internally - always return 0
    202	 * as the packet going to be dropped anyway */
    203	num_queues = READ_ONCE(vif->num_queues);
    204	if (num_queues < 1)
    205		return 0;
    206
    207	if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)
    208		return netdev_pick_tx(dev, skb, NULL) %
    209		       dev->real_num_tx_queues;
    210
    211	xenvif_set_skb_hash(vif, skb);
    212
    213	if (size == 0)
    214		return skb_get_hash_raw(skb) % dev->real_num_tx_queues;
    215
    216	return vif->hash.mapping[vif->hash.mapping_sel]
    217				[skb_get_hash_raw(skb) % size];
    218}
    219
    220static netdev_tx_t
    221xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
    222{
    223	struct xenvif *vif = netdev_priv(dev);
    224	struct xenvif_queue *queue = NULL;
    225	unsigned int num_queues;
    226	u16 index;
    227	struct xenvif_rx_cb *cb;
    228
    229	BUG_ON(skb->dev != dev);
    230
    231	/* Drop the packet if queues are not set up.
    232	 * This handler should be called inside an RCU read section
    233	 * so we don't need to enter it here explicitly.
    234	 */
    235	num_queues = READ_ONCE(vif->num_queues);
    236	if (num_queues < 1)
    237		goto drop;
    238
    239	/* Obtain the queue to be used to transmit this packet */
    240	index = skb_get_queue_mapping(skb);
    241	if (index >= num_queues) {
    242		pr_warn_ratelimited("Invalid queue %hu for packet on interface %s\n",
    243				    index, vif->dev->name);
    244		index %= num_queues;
    245	}
    246	queue = &vif->queues[index];
    247
    248	/* Drop the packet if queue is not ready */
    249	if (queue->task == NULL ||
    250	    queue->dealloc_task == NULL ||
    251	    !xenvif_schedulable(vif))
    252		goto drop;
    253
    254	if (vif->multicast_control && skb->pkt_type == PACKET_MULTICAST) {
    255		struct ethhdr *eth = (struct ethhdr *)skb->data;
    256
    257		if (!xenvif_mcast_match(vif, eth->h_dest))
    258			goto drop;
    259	}
    260
    261	cb = XENVIF_RX_CB(skb);
    262	cb->expires = jiffies + vif->drain_timeout;
    263
    264	/* If there is no hash algorithm configured then make sure there
    265	 * is no hash information in the socket buffer otherwise it
    266	 * would be incorrectly forwarded to the frontend.
    267	 */
    268	if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)
    269		skb_clear_hash(skb);
    270
    271	xenvif_rx_queue_tail(queue, skb);
    272	xenvif_kick_thread(queue);
    273
    274	return NETDEV_TX_OK;
    275
    276 drop:
    277	vif->dev->stats.tx_dropped++;
    278	dev_kfree_skb(skb);
    279	return NETDEV_TX_OK;
    280}
    281
    282static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
    283{
    284	struct xenvif *vif = netdev_priv(dev);
    285	struct xenvif_queue *queue = NULL;
    286	unsigned int num_queues;
    287	u64 rx_bytes = 0;
    288	u64 rx_packets = 0;
    289	u64 tx_bytes = 0;
    290	u64 tx_packets = 0;
    291	unsigned int index;
    292
    293	rcu_read_lock();
    294	num_queues = READ_ONCE(vif->num_queues);
    295
    296	/* Aggregate tx and rx stats from each queue */
    297	for (index = 0; index < num_queues; ++index) {
    298		queue = &vif->queues[index];
    299		rx_bytes += queue->stats.rx_bytes;
    300		rx_packets += queue->stats.rx_packets;
    301		tx_bytes += queue->stats.tx_bytes;
    302		tx_packets += queue->stats.tx_packets;
    303	}
    304
    305	rcu_read_unlock();
    306
    307	vif->dev->stats.rx_bytes = rx_bytes;
    308	vif->dev->stats.rx_packets = rx_packets;
    309	vif->dev->stats.tx_bytes = tx_bytes;
    310	vif->dev->stats.tx_packets = tx_packets;
    311
    312	return &vif->dev->stats;
    313}
    314
    315static void xenvif_up(struct xenvif *vif)
    316{
    317	struct xenvif_queue *queue = NULL;
    318	unsigned int num_queues = vif->num_queues;
    319	unsigned int queue_index;
    320
    321	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
    322		queue = &vif->queues[queue_index];
    323		napi_enable(&queue->napi);
    324		enable_irq(queue->tx_irq);
    325		if (queue->tx_irq != queue->rx_irq)
    326			enable_irq(queue->rx_irq);
    327		xenvif_napi_schedule_or_enable_events(queue);
    328	}
    329}
    330
    331static void xenvif_down(struct xenvif *vif)
    332{
    333	struct xenvif_queue *queue = NULL;
    334	unsigned int num_queues = vif->num_queues;
    335	unsigned int queue_index;
    336
    337	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
    338		queue = &vif->queues[queue_index];
    339		disable_irq(queue->tx_irq);
    340		if (queue->tx_irq != queue->rx_irq)
    341			disable_irq(queue->rx_irq);
    342		napi_disable(&queue->napi);
    343		del_timer_sync(&queue->credit_timeout);
    344	}
    345}
    346
    347static int xenvif_open(struct net_device *dev)
    348{
    349	struct xenvif *vif = netdev_priv(dev);
    350	if (test_bit(VIF_STATUS_CONNECTED, &vif->status))
    351		xenvif_up(vif);
    352	netif_tx_start_all_queues(dev);
    353	return 0;
    354}
    355
    356static int xenvif_close(struct net_device *dev)
    357{
    358	struct xenvif *vif = netdev_priv(dev);
    359	if (test_bit(VIF_STATUS_CONNECTED, &vif->status))
    360		xenvif_down(vif);
    361	netif_tx_stop_all_queues(dev);
    362	return 0;
    363}
    364
    365static int xenvif_change_mtu(struct net_device *dev, int mtu)
    366{
    367	struct xenvif *vif = netdev_priv(dev);
    368	int max = vif->can_sg ? ETH_MAX_MTU - VLAN_ETH_HLEN : ETH_DATA_LEN;
    369
    370	if (mtu > max)
    371		return -EINVAL;
    372	dev->mtu = mtu;
    373	return 0;
    374}
    375
    376static netdev_features_t xenvif_fix_features(struct net_device *dev,
    377	netdev_features_t features)
    378{
    379	struct xenvif *vif = netdev_priv(dev);
    380
    381	if (!vif->can_sg)
    382		features &= ~NETIF_F_SG;
    383	if (~(vif->gso_mask) & GSO_BIT(TCPV4))
    384		features &= ~NETIF_F_TSO;
    385	if (~(vif->gso_mask) & GSO_BIT(TCPV6))
    386		features &= ~NETIF_F_TSO6;
    387	if (!vif->ip_csum)
    388		features &= ~NETIF_F_IP_CSUM;
    389	if (!vif->ipv6_csum)
    390		features &= ~NETIF_F_IPV6_CSUM;
    391
    392	return features;
    393}
    394
    395static const struct xenvif_stat {
    396	char name[ETH_GSTRING_LEN];
    397	u16 offset;
    398} xenvif_stats[] = {
    399	{
    400		"rx_gso_checksum_fixup",
    401		offsetof(struct xenvif_stats, rx_gso_checksum_fixup)
    402	},
    403	/* If (sent != success + fail), there are probably packets never
    404	 * freed up properly!
    405	 */
    406	{
    407		"tx_zerocopy_sent",
    408		offsetof(struct xenvif_stats, tx_zerocopy_sent),
    409	},
    410	{
    411		"tx_zerocopy_success",
    412		offsetof(struct xenvif_stats, tx_zerocopy_success),
    413	},
    414	{
    415		"tx_zerocopy_fail",
    416		offsetof(struct xenvif_stats, tx_zerocopy_fail)
    417	},
    418	/* Number of packets exceeding MAX_SKB_FRAG slots. You should use
    419	 * a guest with the same MAX_SKB_FRAG
    420	 */
    421	{
    422		"tx_frag_overflow",
    423		offsetof(struct xenvif_stats, tx_frag_overflow)
    424	},
    425};
    426
    427static int xenvif_get_sset_count(struct net_device *dev, int string_set)
    428{
    429	switch (string_set) {
    430	case ETH_SS_STATS:
    431		return ARRAY_SIZE(xenvif_stats);
    432	default:
    433		return -EINVAL;
    434	}
    435}
    436
    437static void xenvif_get_ethtool_stats(struct net_device *dev,
    438				     struct ethtool_stats *stats, u64 * data)
    439{
    440	struct xenvif *vif = netdev_priv(dev);
    441	unsigned int num_queues;
    442	int i;
    443	unsigned int queue_index;
    444
    445	rcu_read_lock();
    446	num_queues = READ_ONCE(vif->num_queues);
    447
    448	for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++) {
    449		unsigned long accum = 0;
    450		for (queue_index = 0; queue_index < num_queues; ++queue_index) {
    451			void *vif_stats = &vif->queues[queue_index].stats;
    452			accum += *(unsigned long *)(vif_stats + xenvif_stats[i].offset);
    453		}
    454		data[i] = accum;
    455	}
    456
    457	rcu_read_unlock();
    458}
    459
    460static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
    461{
    462	int i;
    463
    464	switch (stringset) {
    465	case ETH_SS_STATS:
    466		for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
    467			memcpy(data + i * ETH_GSTRING_LEN,
    468			       xenvif_stats[i].name, ETH_GSTRING_LEN);
    469		break;
    470	}
    471}
    472
    473static const struct ethtool_ops xenvif_ethtool_ops = {
    474	.get_link	= ethtool_op_get_link,
    475
    476	.get_sset_count = xenvif_get_sset_count,
    477	.get_ethtool_stats = xenvif_get_ethtool_stats,
    478	.get_strings = xenvif_get_strings,
    479};
    480
    481static const struct net_device_ops xenvif_netdev_ops = {
    482	.ndo_select_queue = xenvif_select_queue,
    483	.ndo_start_xmit	= xenvif_start_xmit,
    484	.ndo_get_stats	= xenvif_get_stats,
    485	.ndo_open	= xenvif_open,
    486	.ndo_stop	= xenvif_close,
    487	.ndo_change_mtu	= xenvif_change_mtu,
    488	.ndo_fix_features = xenvif_fix_features,
    489	.ndo_set_mac_address = eth_mac_addr,
    490	.ndo_validate_addr   = eth_validate_addr,
    491};
    492
    493struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
    494			    unsigned int handle)
    495{
    496	static const u8 dummy_addr[ETH_ALEN] = {
    497		0xfe, 0xff, 0xff, 0xff, 0xff, 0xff,
    498	};
    499	int err;
    500	struct net_device *dev;
    501	struct xenvif *vif;
    502	char name[IFNAMSIZ] = {};
    503
    504	snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
    505	/* Allocate a netdev with the max. supported number of queues.
    506	 * When the guest selects the desired number, it will be updated
    507	 * via netif_set_real_num_*_queues().
    508	 */
    509	dev = alloc_netdev_mq(sizeof(struct xenvif), name, NET_NAME_UNKNOWN,
    510			      ether_setup, xenvif_max_queues);
    511	if (dev == NULL) {
    512		pr_warn("Could not allocate netdev for %s\n", name);
    513		return ERR_PTR(-ENOMEM);
    514	}
    515
    516	SET_NETDEV_DEV(dev, parent);
    517
    518	vif = netdev_priv(dev);
    519
    520	vif->domid  = domid;
    521	vif->handle = handle;
    522	vif->can_sg = 1;
    523	vif->ip_csum = 1;
    524	vif->dev = dev;
    525	vif->disabled = false;
    526	vif->drain_timeout = msecs_to_jiffies(rx_drain_timeout_msecs);
    527	vif->stall_timeout = msecs_to_jiffies(rx_stall_timeout_msecs);
    528
    529	/* Start out with no queues. */
    530	vif->queues = NULL;
    531	vif->num_queues = 0;
    532
    533	vif->xdp_headroom = 0;
    534
    535	spin_lock_init(&vif->lock);
    536	INIT_LIST_HEAD(&vif->fe_mcast_addr);
    537
    538	dev->netdev_ops	= &xenvif_netdev_ops;
    539	dev->hw_features = NETIF_F_SG |
    540		NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
    541		NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_FRAGLIST;
    542	dev->features = dev->hw_features | NETIF_F_RXCSUM;
    543	dev->ethtool_ops = &xenvif_ethtool_ops;
    544
    545	dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
    546
    547	dev->min_mtu = ETH_MIN_MTU;
    548	dev->max_mtu = ETH_MAX_MTU - VLAN_ETH_HLEN;
    549
    550	/*
    551	 * Initialise a dummy MAC address. We choose the numerically
    552	 * largest non-broadcast address to prevent the address getting
    553	 * stolen by an Ethernet bridge for STP purposes.
    554	 * (FE:FF:FF:FF:FF:FF)
    555	 */
    556	eth_hw_addr_set(dev, dummy_addr);
    557
    558	netif_carrier_off(dev);
    559
    560	err = register_netdev(dev);
    561	if (err) {
    562		netdev_warn(dev, "Could not register device: err=%d\n", err);
    563		free_netdev(dev);
    564		return ERR_PTR(err);
    565	}
    566
    567	netdev_dbg(dev, "Successfully created xenvif\n");
    568
    569	__module_get(THIS_MODULE);
    570
    571	return vif;
    572}
    573
    574int xenvif_init_queue(struct xenvif_queue *queue)
    575{
    576	int err, i;
    577
    578	queue->credit_bytes = queue->remaining_credit = ~0UL;
    579	queue->credit_usec  = 0UL;
    580	timer_setup(&queue->credit_timeout, xenvif_tx_credit_callback, 0);
    581	queue->credit_window_start = get_jiffies_64();
    582
    583	queue->rx_queue_max = XENVIF_RX_QUEUE_BYTES;
    584
    585	skb_queue_head_init(&queue->rx_queue);
    586	skb_queue_head_init(&queue->tx_queue);
    587
    588	queue->pending_cons = 0;
    589	queue->pending_prod = MAX_PENDING_REQS;
    590	for (i = 0; i < MAX_PENDING_REQS; ++i)
    591		queue->pending_ring[i] = i;
    592
    593	spin_lock_init(&queue->callback_lock);
    594	spin_lock_init(&queue->response_lock);
    595
    596	/* If ballooning is disabled, this will consume real memory, so you
    597	 * better enable it. The long term solution would be to use just a
    598	 * bunch of valid page descriptors, without dependency on ballooning
    599	 */
    600	err = gnttab_alloc_pages(MAX_PENDING_REQS,
    601				 queue->mmap_pages);
    602	if (err) {
    603		netdev_err(queue->vif->dev, "Could not reserve mmap_pages\n");
    604		return -ENOMEM;
    605	}
    606
    607	for (i = 0; i < MAX_PENDING_REQS; i++) {
    608		queue->pending_tx_info[i].callback_struct = (struct ubuf_info)
    609			{ .callback = xenvif_zerocopy_callback,
    610			  { { .ctx = NULL,
    611			      .desc = i } } };
    612		queue->grant_tx_handle[i] = NETBACK_INVALID_HANDLE;
    613	}
    614
    615	return 0;
    616}
    617
    618void xenvif_carrier_on(struct xenvif *vif)
    619{
    620	rtnl_lock();
    621	if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
    622		dev_set_mtu(vif->dev, ETH_DATA_LEN);
    623	netdev_update_features(vif->dev);
    624	set_bit(VIF_STATUS_CONNECTED, &vif->status);
    625	if (netif_running(vif->dev))
    626		xenvif_up(vif);
    627	rtnl_unlock();
    628}
    629
    630int xenvif_connect_ctrl(struct xenvif *vif, grant_ref_t ring_ref,
    631			unsigned int evtchn)
    632{
    633	struct net_device *dev = vif->dev;
    634	struct xenbus_device *xendev = xenvif_to_xenbus_device(vif);
    635	void *addr;
    636	struct xen_netif_ctrl_sring *shared;
    637	RING_IDX rsp_prod, req_prod;
    638	int err;
    639
    640	err = xenbus_map_ring_valloc(xendev, &ring_ref, 1, &addr);
    641	if (err)
    642		goto err;
    643
    644	shared = (struct xen_netif_ctrl_sring *)addr;
    645	rsp_prod = READ_ONCE(shared->rsp_prod);
    646	req_prod = READ_ONCE(shared->req_prod);
    647
    648	BACK_RING_ATTACH(&vif->ctrl, shared, rsp_prod, XEN_PAGE_SIZE);
    649
    650	err = -EIO;
    651	if (req_prod - rsp_prod > RING_SIZE(&vif->ctrl))
    652		goto err_unmap;
    653
    654	err = bind_interdomain_evtchn_to_irq_lateeoi(xendev, evtchn);
    655	if (err < 0)
    656		goto err_unmap;
    657
    658	vif->ctrl_irq = err;
    659
    660	xenvif_init_hash(vif);
    661
    662	err = request_threaded_irq(vif->ctrl_irq, NULL, xenvif_ctrl_irq_fn,
    663				   IRQF_ONESHOT, "xen-netback-ctrl", vif);
    664	if (err) {
    665		pr_warn("Could not setup irq handler for %s\n", dev->name);
    666		goto err_deinit;
    667	}
    668
    669	return 0;
    670
    671err_deinit:
    672	xenvif_deinit_hash(vif);
    673	unbind_from_irqhandler(vif->ctrl_irq, vif);
    674	vif->ctrl_irq = 0;
    675
    676err_unmap:
    677	xenbus_unmap_ring_vfree(xendev, vif->ctrl.sring);
    678	vif->ctrl.sring = NULL;
    679
    680err:
    681	return err;
    682}
    683
    684static void xenvif_disconnect_queue(struct xenvif_queue *queue)
    685{
    686	if (queue->task) {
    687		kthread_stop(queue->task);
    688		put_task_struct(queue->task);
    689		queue->task = NULL;
    690	}
    691
    692	if (queue->dealloc_task) {
    693		kthread_stop(queue->dealloc_task);
    694		queue->dealloc_task = NULL;
    695	}
    696
    697	if (queue->napi.poll) {
    698		netif_napi_del(&queue->napi);
    699		queue->napi.poll = NULL;
    700	}
    701
    702	if (queue->tx_irq) {
    703		unbind_from_irqhandler(queue->tx_irq, queue);
    704		if (queue->tx_irq == queue->rx_irq)
    705			queue->rx_irq = 0;
    706		queue->tx_irq = 0;
    707	}
    708
    709	if (queue->rx_irq) {
    710		unbind_from_irqhandler(queue->rx_irq, queue);
    711		queue->rx_irq = 0;
    712	}
    713
    714	xenvif_unmap_frontend_data_rings(queue);
    715}
    716
    717int xenvif_connect_data(struct xenvif_queue *queue,
    718			unsigned long tx_ring_ref,
    719			unsigned long rx_ring_ref,
    720			unsigned int tx_evtchn,
    721			unsigned int rx_evtchn)
    722{
    723	struct xenbus_device *dev = xenvif_to_xenbus_device(queue->vif);
    724	struct task_struct *task;
    725	int err;
    726
    727	BUG_ON(queue->tx_irq);
    728	BUG_ON(queue->task);
    729	BUG_ON(queue->dealloc_task);
    730
    731	err = xenvif_map_frontend_data_rings(queue, tx_ring_ref,
    732					     rx_ring_ref);
    733	if (err < 0)
    734		goto err;
    735
    736	init_waitqueue_head(&queue->wq);
    737	init_waitqueue_head(&queue->dealloc_wq);
    738	atomic_set(&queue->inflight_packets, 0);
    739
    740	netif_napi_add(queue->vif->dev, &queue->napi, xenvif_poll,
    741			NAPI_POLL_WEIGHT);
    742
    743	queue->stalled = true;
    744
    745	task = kthread_run(xenvif_kthread_guest_rx, queue,
    746			   "%s-guest-rx", queue->name);
    747	if (IS_ERR(task))
    748		goto kthread_err;
    749	queue->task = task;
    750	/*
    751	 * Take a reference to the task in order to prevent it from being freed
    752	 * if the thread function returns before kthread_stop is called.
    753	 */
    754	get_task_struct(task);
    755
    756	task = kthread_run(xenvif_dealloc_kthread, queue,
    757			   "%s-dealloc", queue->name);
    758	if (IS_ERR(task))
    759		goto kthread_err;
    760	queue->dealloc_task = task;
    761
    762	if (tx_evtchn == rx_evtchn) {
    763		/* feature-split-event-channels == 0 */
    764		err = bind_interdomain_evtchn_to_irqhandler_lateeoi(
    765			dev, tx_evtchn, xenvif_interrupt, 0,
    766			queue->name, queue);
    767		if (err < 0)
    768			goto err;
    769		queue->tx_irq = queue->rx_irq = err;
    770		disable_irq(queue->tx_irq);
    771	} else {
    772		/* feature-split-event-channels == 1 */
    773		snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name),
    774			 "%s-tx", queue->name);
    775		err = bind_interdomain_evtchn_to_irqhandler_lateeoi(
    776			dev, tx_evtchn, xenvif_tx_interrupt, 0,
    777			queue->tx_irq_name, queue);
    778		if (err < 0)
    779			goto err;
    780		queue->tx_irq = err;
    781		disable_irq(queue->tx_irq);
    782
    783		snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name),
    784			 "%s-rx", queue->name);
    785		err = bind_interdomain_evtchn_to_irqhandler_lateeoi(
    786			dev, rx_evtchn, xenvif_rx_interrupt, 0,
    787			queue->rx_irq_name, queue);
    788		if (err < 0)
    789			goto err;
    790		queue->rx_irq = err;
    791		disable_irq(queue->rx_irq);
    792	}
    793
    794	return 0;
    795
    796kthread_err:
    797	pr_warn("Could not allocate kthread for %s\n", queue->name);
    798	err = PTR_ERR(task);
    799err:
    800	xenvif_disconnect_queue(queue);
    801	return err;
    802}
    803
    804void xenvif_carrier_off(struct xenvif *vif)
    805{
    806	struct net_device *dev = vif->dev;
    807
    808	rtnl_lock();
    809	if (test_and_clear_bit(VIF_STATUS_CONNECTED, &vif->status)) {
    810		netif_carrier_off(dev); /* discard queued packets */
    811		if (netif_running(dev))
    812			xenvif_down(vif);
    813	}
    814	rtnl_unlock();
    815}
    816
    817void xenvif_disconnect_data(struct xenvif *vif)
    818{
    819	struct xenvif_queue *queue = NULL;
    820	unsigned int num_queues = vif->num_queues;
    821	unsigned int queue_index;
    822
    823	xenvif_carrier_off(vif);
    824
    825	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
    826		queue = &vif->queues[queue_index];
    827
    828		xenvif_disconnect_queue(queue);
    829	}
    830
    831	xenvif_mcast_addr_list_free(vif);
    832}
    833
    834void xenvif_disconnect_ctrl(struct xenvif *vif)
    835{
    836	if (vif->ctrl_irq) {
    837		xenvif_deinit_hash(vif);
    838		unbind_from_irqhandler(vif->ctrl_irq, vif);
    839		vif->ctrl_irq = 0;
    840	}
    841
    842	if (vif->ctrl.sring) {
    843		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
    844					vif->ctrl.sring);
    845		vif->ctrl.sring = NULL;
    846	}
    847}
    848
    849/* Reverse the relevant parts of xenvif_init_queue().
    850 * Used for queue teardown from xenvif_free(), and on the
    851 * error handling paths in xenbus.c:connect().
    852 */
    853void xenvif_deinit_queue(struct xenvif_queue *queue)
    854{
    855	gnttab_free_pages(MAX_PENDING_REQS, queue->mmap_pages);
    856}
    857
    858void xenvif_free(struct xenvif *vif)
    859{
    860	struct xenvif_queue *queues = vif->queues;
    861	unsigned int num_queues = vif->num_queues;
    862	unsigned int queue_index;
    863
    864	unregister_netdev(vif->dev);
    865	free_netdev(vif->dev);
    866
    867	for (queue_index = 0; queue_index < num_queues; ++queue_index)
    868		xenvif_deinit_queue(&queues[queue_index]);
    869	vfree(queues);
    870
    871	module_put(THIS_MODULE);
    872}