1 files changed, 856 insertions, 0 deletions

diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
new file mode 100644
index 000000000..09fc4bc06
--- /dev/null
+++ b/drivers/net/xen-netback/interface.c
@@ -0,0 +1,856 @@
+/*
+ * Network-device interface management.
+ *
+ * Copyright (c) 2004-2005, Keir Fraser
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "common.h"
+
+#include <linux/kthread.h>
+#include <linux/sched/task.h>
+#include <linux/ethtool.h>
+#include <linux/rtnetlink.h>
+#include <linux/if_vlan.h>
+#include <linux/vmalloc.h>
+
+#include <xen/events.h>
+#include <asm/xen/hypercall.h>
+#include <xen/balloon.h>
+
+#define XENVIF_NAPI_WEIGHT  64
+
+/* Number of bytes allowed on the internal guest Rx queue. */
+#define XENVIF_RX_QUEUE_BYTES (XEN_NETIF_RX_RING_SIZE/2 * PAGE_SIZE)
+
+/* This function is used to set SKBTX_DEV_ZEROCOPY as well as
+ * increasing the inflight counter. We need to increase the inflight
+ * counter because core driver calls into xenvif_zerocopy_callback
+ * which calls xenvif_skb_zerocopy_complete.
+ */
+void xenvif_skb_zerocopy_prepare(struct xenvif_queue *queue,
+				 struct sk_buff *skb)
+{
+	skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
+	atomic_inc(&queue->inflight_packets);
+}
+
+void xenvif_skb_zerocopy_complete(struct xenvif_queue *queue)
+{
+	atomic_dec(&queue->inflight_packets);
+
+	/* Wake the dealloc thread _after_ decrementing inflight_packets so
+	 * that if kthread_stop() has already been called, the dealloc thread
+	 * does not wait forever with nothing to wake it.
+	 */
+	wake_up(&queue->dealloc_wq);
+}
+
+static int xenvif_schedulable(struct xenvif *vif)
+{
+	return netif_running(vif->dev) &&
+		test_bit(VIF_STATUS_CONNECTED, &vif->status) &&
+		!vif->disabled;
+}
+
+static bool xenvif_handle_tx_interrupt(struct xenvif_queue *queue)
+{
+	bool rc;
+
+	rc = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx);
+	if (rc)
+		napi_schedule(&queue->napi);
+	return rc;
+}
+
+static irqreturn_t xenvif_tx_interrupt(int irq, void *dev_id)
+{
+	struct xenvif_queue *queue = dev_id;
+	int old;
+
+	old = atomic_fetch_or(NETBK_TX_EOI, &queue->eoi_pending);
+	WARN(old & NETBK_TX_EOI, "Interrupt while EOI pending\n");
+
+	if (!xenvif_handle_tx_interrupt(queue)) {
+		atomic_andnot(NETBK_TX_EOI, &queue->eoi_pending);
+		xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int xenvif_poll(struct napi_struct *napi, int budget)
+{
+	struct xenvif_queue *queue =
+		container_of(napi, struct xenvif_queue, napi);
+	int work_done;
+
+	/* This vif is rogue, we pretend we've there is nothing to do
+	 * for this vif to deschedule it from NAPI. But this interface
+	 * will be turned off in thread context later.
+	 */
+	if (unlikely(queue->vif->disabled)) {
+		napi_complete(napi);
+		return 0;
+	}
+
+	work_done = xenvif_tx_action(queue, budget);
+
+	if (work_done < budget) {
+		napi_complete_done(napi, work_done);
+		/* If the queue is rate-limited, it shall be
+		 * rescheduled in the timer callback.
+		 */
+		if (likely(!queue->rate_limited))
+			xenvif_napi_schedule_or_enable_events(queue);
+	}
+
+	return work_done;
+}
+
+static bool xenvif_handle_rx_interrupt(struct xenvif_queue *queue)
+{
+	bool rc;
+
+	rc = xenvif_have_rx_work(queue, false);
+	if (rc)
+		xenvif_kick_thread(queue);
+	return rc;
+}
+
+static irqreturn_t xenvif_rx_interrupt(int irq, void *dev_id)
+{
+	struct xenvif_queue *queue = dev_id;
+	int old;
+
+	old = atomic_fetch_or(NETBK_RX_EOI, &queue->eoi_pending);
+	WARN(old & NETBK_RX_EOI, "Interrupt while EOI pending\n");
+
+	if (!xenvif_handle_rx_interrupt(queue)) {
+		atomic_andnot(NETBK_RX_EOI, &queue->eoi_pending);
+		xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS);
+	}
+
+	return IRQ_HANDLED;
+}
+
+irqreturn_t xenvif_interrupt(int irq, void *dev_id)
+{
+	struct xenvif_queue *queue = dev_id;
+	int old;
+	bool has_rx, has_tx;
+
+	old = atomic_fetch_or(NETBK_COMMON_EOI, &queue->eoi_pending);
+	WARN(old, "Interrupt while EOI pending\n");
+
+	has_tx = xenvif_handle_tx_interrupt(queue);
+	has_rx = xenvif_handle_rx_interrupt(queue);
+
+	if (!has_rx && !has_tx) {
+		atomic_andnot(NETBK_COMMON_EOI, &queue->eoi_pending);
+		xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static u16 xenvif_select_queue(struct net_device *dev, struct sk_buff *skb,
+			       struct net_device *sb_dev)
+{
+	struct xenvif *vif = netdev_priv(dev);
+	unsigned int size = vif->hash.size;
+	unsigned int num_queues;
+
+	/* If queues are not set up internally - always return 0
+	 * as the packet going to be dropped anyway */
+	num_queues = READ_ONCE(vif->num_queues);
+	if (num_queues < 1)
+		return 0;
+
+	if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)
+		return netdev_pick_tx(dev, skb, NULL) %
+		       dev->real_num_tx_queues;
+
+	xenvif_set_skb_hash(vif, skb);
+
+	if (size == 0)
+		return skb_get_hash_raw(skb) % dev->real_num_tx_queues;
+
+	return vif->hash.mapping[vif->hash.mapping_sel]
+				[skb_get_hash_raw(skb) % size];
+}
+
+static netdev_tx_t
+xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct xenvif *vif = netdev_priv(dev);
+	struct xenvif_queue *queue = NULL;
+	unsigned int num_queues;
+	u16 index;
+	struct xenvif_rx_cb *cb;
+
+	BUG_ON(skb->dev != dev);
+
+	/* Drop the packet if queues are not set up.
+	 * This handler should be called inside an RCU read section
+	 * so we don't need to enter it here explicitly.
+	 */
+	num_queues = READ_ONCE(vif->num_queues);
+	if (num_queues < 1)
+		goto drop;
+
+	/* Obtain the queue to be used to transmit this packet */
+	index = skb_get_queue_mapping(skb);
+	if (index >= num_queues) {
+		pr_warn_ratelimited("Invalid queue %hu for packet on interface %s\n",
+				    index, vif->dev->name);
+		index %= num_queues;
+	}
+	queue = &vif->queues[index];
+
+	/* Drop the packet if queue is not ready */
+	if (queue->task == NULL ||
+	    queue->dealloc_task == NULL ||
+	    !xenvif_schedulable(vif))
+		goto drop;
+
+	if (vif->multicast_control && skb->pkt_type == PACKET_MULTICAST) {
+		struct ethhdr *eth = (struct ethhdr *)skb->data;
+
+		if (!xenvif_mcast_match(vif, eth->h_dest))
+			goto drop;
+	}
+
+	cb = XENVIF_RX_CB(skb);
+	cb->expires = jiffies + vif->drain_timeout;
+
+	/* If there is no hash algorithm configured then make sure there
+	 * is no hash information in the socket buffer otherwise it
+	 * would be incorrectly forwarded to the frontend.
+	 */
+	if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)
+		skb_clear_hash(skb);
+
+	if (!xenvif_rx_queue_tail(queue, skb))
+		goto drop;
+
+	xenvif_kick_thread(queue);
+
+	return NETDEV_TX_OK;
+
+ drop:
+	vif->dev->stats.tx_dropped++;
+	dev_kfree_skb_any(skb);
+	return NETDEV_TX_OK;
+}
+
+static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
+{
+	struct xenvif *vif = netdev_priv(dev);
+	struct xenvif_queue *queue = NULL;
+	unsigned int num_queues;
+	u64 rx_bytes = 0;
+	u64 rx_packets = 0;
+	u64 tx_bytes = 0;
+	u64 tx_packets = 0;
+	unsigned int index;
+
+	rcu_read_lock();
+	num_queues = READ_ONCE(vif->num_queues);
+
+	/* Aggregate tx and rx stats from each queue */
+	for (index = 0; index < num_queues; ++index) {
+		queue = &vif->queues[index];
+		rx_bytes += queue->stats.rx_bytes;
+		rx_packets += queue->stats.rx_packets;
+		tx_bytes += queue->stats.tx_bytes;
+		tx_packets += queue->stats.tx_packets;
+	}
+
+	rcu_read_unlock();
+
+	vif->dev->stats.rx_bytes = rx_bytes;
+	vif->dev->stats.rx_packets = rx_packets;
+	vif->dev->stats.tx_bytes = tx_bytes;
+	vif->dev->stats.tx_packets = tx_packets;
+
+	return &vif->dev->stats;
+}
+
+static void xenvif_up(struct xenvif *vif)
+{
+	struct xenvif_queue *queue = NULL;
+	unsigned int num_queues = vif->num_queues;
+	unsigned int queue_index;
+
+	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
+		queue = &vif->queues[queue_index];
+		napi_enable(&queue->napi);
+		enable_irq(queue->tx_irq);
+		if (queue->tx_irq != queue->rx_irq)
+			enable_irq(queue->rx_irq);
+		xenvif_napi_schedule_or_enable_events(queue);
+	}
+}
+
+static void xenvif_down(struct xenvif *vif)
+{
+	struct xenvif_queue *queue = NULL;
+	unsigned int num_queues = vif->num_queues;
+	unsigned int queue_index;
+
+	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
+		queue = &vif->queues[queue_index];
+		disable_irq(queue->tx_irq);
+		if (queue->tx_irq != queue->rx_irq)
+			disable_irq(queue->rx_irq);
+		napi_disable(&queue->napi);
+		del_timer_sync(&queue->credit_timeout);
+	}
+}
+
+static int xenvif_open(struct net_device *dev)
+{
+	struct xenvif *vif = netdev_priv(dev);
+	if (test_bit(VIF_STATUS_CONNECTED, &vif->status))
+		xenvif_up(vif);
+	netif_tx_start_all_queues(dev);
+	return 0;
+}
+
+static int xenvif_close(struct net_device *dev)
+{
+	struct xenvif *vif = netdev_priv(dev);
+	if (test_bit(VIF_STATUS_CONNECTED, &vif->status))
+		xenvif_down(vif);
+	netif_tx_stop_all_queues(dev);
+	return 0;
+}
+
+static int xenvif_change_mtu(struct net_device *dev, int mtu)
+{
+	struct xenvif *vif = netdev_priv(dev);
+	int max = vif->can_sg ? ETH_MAX_MTU - VLAN_ETH_HLEN : ETH_DATA_LEN;
+
+	if (mtu > max)
+		return -EINVAL;
+	dev->mtu = mtu;
+	return 0;
+}
+
+static netdev_features_t xenvif_fix_features(struct net_device *dev,
+	netdev_features_t features)
+{
+	struct xenvif *vif = netdev_priv(dev);
+
+	if (!vif->can_sg)
+		features &= ~NETIF_F_SG;
+	if (~(vif->gso_mask) & GSO_BIT(TCPV4))
+		features &= ~NETIF_F_TSO;
+	if (~(vif->gso_mask) & GSO_BIT(TCPV6))
+		features &= ~NETIF_F_TSO6;
+	if (!vif->ip_csum)
+		features &= ~NETIF_F_IP_CSUM;
+	if (!vif->ipv6_csum)
+		features &= ~NETIF_F_IPV6_CSUM;
+
+	return features;
+}
+
+static const struct xenvif_stat {
+	char name[ETH_GSTRING_LEN];
+	u16 offset;
+} xenvif_stats[] = {
+	{
+		"rx_gso_checksum_fixup",
+		offsetof(struct xenvif_stats, rx_gso_checksum_fixup)
+	},
+	/* If (sent != success + fail), there are probably packets never
+	 * freed up properly!
+	 */
+	{
+		"tx_zerocopy_sent",
+		offsetof(struct xenvif_stats, tx_zerocopy_sent),
+	},
+	{
+		"tx_zerocopy_success",
+		offsetof(struct xenvif_stats, tx_zerocopy_success),
+	},
+	{
+		"tx_zerocopy_fail",
+		offsetof(struct xenvif_stats, tx_zerocopy_fail)
+	},
+	/* Number of packets exceeding MAX_SKB_FRAG slots. You should use
+	 * a guest with the same MAX_SKB_FRAG
+	 */
+	{
+		"tx_frag_overflow",
+		offsetof(struct xenvif_stats, tx_frag_overflow)
+	},
+};
+
+static int xenvif_get_sset_count(struct net_device *dev, int string_set)
+{
+	switch (string_set) {
+	case ETH_SS_STATS:
+		return ARRAY_SIZE(xenvif_stats);
+	default:
+		return -EINVAL;
+	}
+}
+
+static void xenvif_get_ethtool_stats(struct net_device *dev,
+				     struct ethtool_stats *stats, u64 * data)
+{
+	struct xenvif *vif = netdev_priv(dev);
+	unsigned int num_queues;
+	int i;
+	unsigned int queue_index;
+
+	rcu_read_lock();
+	num_queues = READ_ONCE(vif->num_queues);
+
+	for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++) {
+		unsigned long accum = 0;
+		for (queue_index = 0; queue_index < num_queues; ++queue_index) {
+			void *vif_stats = &vif->queues[queue_index].stats;
+			accum += *(unsigned long *)(vif_stats + xenvif_stats[i].offset);
+		}
+		data[i] = accum;
+	}
+
+	rcu_read_unlock();
+}
+
+static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
+{
+	int i;
+
+	switch (stringset) {
+	case ETH_SS_STATS:
+		for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
+			memcpy(data + i * ETH_GSTRING_LEN,
+			       xenvif_stats[i].name, ETH_GSTRING_LEN);
+		break;
+	}
+}
+
+static const struct ethtool_ops xenvif_ethtool_ops = {
+	.get_link	= ethtool_op_get_link,
+
+	.get_sset_count = xenvif_get_sset_count,
+	.get_ethtool_stats = xenvif_get_ethtool_stats,
+	.get_strings = xenvif_get_strings,
+};
+
+static const struct net_device_ops xenvif_netdev_ops = {
+	.ndo_select_queue = xenvif_select_queue,
+	.ndo_start_xmit	= xenvif_start_xmit,
+	.ndo_get_stats	= xenvif_get_stats,
+	.ndo_open	= xenvif_open,
+	.ndo_stop	= xenvif_close,
+	.ndo_change_mtu	= xenvif_change_mtu,
+	.ndo_fix_features = xenvif_fix_features,
+	.ndo_set_mac_address = eth_mac_addr,
+	.ndo_validate_addr   = eth_validate_addr,
+};
+
+struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
+			    unsigned int handle)
+{
+	int err;
+	struct net_device *dev;
+	struct xenvif *vif;
+	char name[IFNAMSIZ] = {};
+
+	snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
+	/* Allocate a netdev with the max. supported number of queues.
+	 * When the guest selects the desired number, it will be updated
+	 * via netif_set_real_num_*_queues().
+	 */
+	dev = alloc_netdev_mq(sizeof(struct xenvif), name, NET_NAME_UNKNOWN,
+			      ether_setup, xenvif_max_queues);
+	if (dev == NULL) {
+		pr_warn("Could not allocate netdev for %s\n", name);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	SET_NETDEV_DEV(dev, parent);
+
+	vif = netdev_priv(dev);
+
+	vif->domid  = domid;
+	vif->handle = handle;
+	vif->can_sg = 1;
+	vif->ip_csum = 1;
+	vif->dev = dev;
+	vif->disabled = false;
+	vif->drain_timeout = msecs_to_jiffies(rx_drain_timeout_msecs);
+	vif->stall_timeout = msecs_to_jiffies(rx_stall_timeout_msecs);
+
+	/* Start out with no queues. */
+	vif->queues = NULL;
+	vif->num_queues = 0;
+
+	vif->xdp_headroom = 0;
+
+	spin_lock_init(&vif->lock);
+	INIT_LIST_HEAD(&vif->fe_mcast_addr);
+
+	dev->netdev_ops	= &xenvif_netdev_ops;
+	dev->hw_features = NETIF_F_SG |
+		NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
+		NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_FRAGLIST;
+	dev->features = dev->hw_features | NETIF_F_RXCSUM;
+	dev->ethtool_ops = &xenvif_ethtool_ops;
+
+	dev->min_mtu = ETH_MIN_MTU;
+	dev->max_mtu = ETH_MAX_MTU - VLAN_ETH_HLEN;
+
+	/*
+	 * Initialise a dummy MAC address. We choose the numerically
+	 * largest non-broadcast address to prevent the address getting
+	 * stolen by an Ethernet bridge for STP purposes.
+	 * (FE:FF:FF:FF:FF:FF)
+	 */
+	eth_broadcast_addr(dev->dev_addr);
+	dev->dev_addr[0] &= ~0x01;
+
+	netif_carrier_off(dev);
+
+	err = register_netdev(dev);
+	if (err) {
+		netdev_warn(dev, "Could not register device: err=%d\n", err);
+		free_netdev(dev);
+		return ERR_PTR(err);
+	}
+
+	netdev_dbg(dev, "Successfully created xenvif\n");
+
+	__module_get(THIS_MODULE);
+
+	return vif;
+}
+
+int xenvif_init_queue(struct xenvif_queue *queue)
+{
+	int err, i;
+
+	queue->credit_bytes = queue->remaining_credit = ~0UL;
+	queue->credit_usec  = 0UL;
+	timer_setup(&queue->credit_timeout, xenvif_tx_credit_callback, 0);
+	queue->credit_window_start = get_jiffies_64();
+
+	queue->rx_queue_max = XENVIF_RX_QUEUE_BYTES;
+
+	skb_queue_head_init(&queue->rx_queue);
+	skb_queue_head_init(&queue->tx_queue);
+
+	queue->pending_cons = 0;
+	queue->pending_prod = MAX_PENDING_REQS;
+	for (i = 0; i < MAX_PENDING_REQS; ++i)
+		queue->pending_ring[i] = i;
+
+	spin_lock_init(&queue->callback_lock);
+	spin_lock_init(&queue->response_lock);
+
+	/* If ballooning is disabled, this will consume real memory, so you
+	 * better enable it. The long term solution would be to use just a
+	 * bunch of valid page descriptors, without dependency on ballooning
+	 */
+	err = gnttab_alloc_pages(MAX_PENDING_REQS,
+				 queue->mmap_pages);
+	if (err) {
+		netdev_err(queue->vif->dev, "Could not reserve mmap_pages\n");
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < MAX_PENDING_REQS; i++) {
+		queue->pending_tx_info[i].callback_struct = (struct ubuf_info)
+			{ .callback = xenvif_zerocopy_callback,
+			  { { .ctx = NULL,
+			      .desc = i } } };
+		queue->grant_tx_handle[i] = NETBACK_INVALID_HANDLE;
+	}
+
+	return 0;
+}
+
+void xenvif_carrier_on(struct xenvif *vif)
+{
+	rtnl_lock();
+	if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
+		dev_set_mtu(vif->dev, ETH_DATA_LEN);
+	netdev_update_features(vif->dev);
+	set_bit(VIF_STATUS_CONNECTED, &vif->status);
+	if (netif_running(vif->dev))
+		xenvif_up(vif);
+	rtnl_unlock();
+}
+
+int xenvif_connect_ctrl(struct xenvif *vif, grant_ref_t ring_ref,
+			unsigned int evtchn)
+{
+	struct net_device *dev = vif->dev;
+	void *addr;
+	struct xen_netif_ctrl_sring *shared;
+	RING_IDX rsp_prod, req_prod;
+	int err;
+
+	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
+				     &ring_ref, 1, &addr);
+	if (err)
+		goto err;
+
+	shared = (struct xen_netif_ctrl_sring *)addr;
+	rsp_prod = READ_ONCE(shared->rsp_prod);
+	req_prod = READ_ONCE(shared->req_prod);
+
+	BACK_RING_ATTACH(&vif->ctrl, shared, rsp_prod, XEN_PAGE_SIZE);
+
+	err = -EIO;
+	if (req_prod - rsp_prod > RING_SIZE(&vif->ctrl))
+		goto err_unmap;
+
+	err = bind_interdomain_evtchn_to_irq_lateeoi(vif->domid, evtchn);
+	if (err < 0)
+		goto err_unmap;
+
+	vif->ctrl_irq = err;
+
+	xenvif_init_hash(vif);
+
+	err = request_threaded_irq(vif->ctrl_irq, NULL, xenvif_ctrl_irq_fn,
+				   IRQF_ONESHOT, "xen-netback-ctrl", vif);
+	if (err) {
+		pr_warn("Could not setup irq handler for %s\n", dev->name);
+		goto err_deinit;
+	}
+
+	return 0;
+
+err_deinit:
+	xenvif_deinit_hash(vif);
+	unbind_from_irqhandler(vif->ctrl_irq, vif);
+	vif->ctrl_irq = 0;
+
+err_unmap:
+	xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
+				vif->ctrl.sring);
+	vif->ctrl.sring = NULL;
+
+err:
+	return err;
+}
+
+static void xenvif_disconnect_queue(struct xenvif_queue *queue)
+{
+	if (queue->task) {
+		kthread_stop(queue->task);
+		put_task_struct(queue->task);
+		queue->task = NULL;
+	}
+
+	if (queue->dealloc_task) {
+		kthread_stop(queue->dealloc_task);
+		queue->dealloc_task = NULL;
+	}
+
+	if (queue->napi.poll) {
+		netif_napi_del(&queue->napi);
+		queue->napi.poll = NULL;
+	}
+
+	if (queue->tx_irq) {
+		unbind_from_irqhandler(queue->tx_irq, queue);
+		if (queue->tx_irq == queue->rx_irq)
+			queue->rx_irq = 0;
+		queue->tx_irq = 0;
+	}
+
+	if (queue->rx_irq) {
+		unbind_from_irqhandler(queue->rx_irq, queue);
+		queue->rx_irq = 0;
+	}
+
+	xenvif_unmap_frontend_data_rings(queue);
+}
+
+int xenvif_connect_data(struct xenvif_queue *queue,
+			unsigned long tx_ring_ref,
+			unsigned long rx_ring_ref,
+			unsigned int tx_evtchn,
+			unsigned int rx_evtchn)
+{
+	struct task_struct *task;
+	int err;
+
+	BUG_ON(queue->tx_irq);
+	BUG_ON(queue->task);
+	BUG_ON(queue->dealloc_task);
+
+	err = xenvif_map_frontend_data_rings(queue, tx_ring_ref,
+					     rx_ring_ref);
+	if (err < 0)
+		goto err;
+
+	init_waitqueue_head(&queue->wq);
+	init_waitqueue_head(&queue->dealloc_wq);
+	atomic_set(&queue->inflight_packets, 0);
+
+	netif_napi_add(queue->vif->dev, &queue->napi, xenvif_poll,
+			XENVIF_NAPI_WEIGHT);
+
+	queue->stalled = true;
+
+	task = kthread_run(xenvif_kthread_guest_rx, queue,
+			   "%s-guest-rx", queue->name);
+	if (IS_ERR(task))
+		goto kthread_err;
+	queue->task = task;
+	/*
+	 * Take a reference to the task in order to prevent it from being freed
+	 * if the thread function returns before kthread_stop is called.
+	 */
+	get_task_struct(task);
+
+	task = kthread_run(xenvif_dealloc_kthread, queue,
+			   "%s-dealloc", queue->name);
+	if (IS_ERR(task))
+		goto kthread_err;
+	queue->dealloc_task = task;
+
+	if (tx_evtchn == rx_evtchn) {
+		/* feature-split-event-channels == 0 */
+		err = bind_interdomain_evtchn_to_irqhandler_lateeoi(
+			queue->vif->domid, tx_evtchn, xenvif_interrupt, 0,
+			queue->name, queue);
+		if (err < 0)
+			goto err;
+		queue->tx_irq = queue->rx_irq = err;
+		disable_irq(queue->tx_irq);
+	} else {
+		/* feature-split-event-channels == 1 */
+		snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name),
+			 "%s-tx", queue->name);
+		err = bind_interdomain_evtchn_to_irqhandler_lateeoi(
+			queue->vif->domid, tx_evtchn, xenvif_tx_interrupt, 0,
+			queue->tx_irq_name, queue);
+		if (err < 0)
+			goto err;
+		queue->tx_irq = err;
+		disable_irq(queue->tx_irq);
+
+		snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name),
+			 "%s-rx", queue->name);
+		err = bind_interdomain_evtchn_to_irqhandler_lateeoi(
+			queue->vif->domid, rx_evtchn, xenvif_rx_interrupt, 0,
+			queue->rx_irq_name, queue);
+		if (err < 0)
+			goto err;
+		queue->rx_irq = err;
+		disable_irq(queue->rx_irq);
+	}
+
+	return 0;
+
+kthread_err:
+	pr_warn("Could not allocate kthread for %s\n", queue->name);
+	err = PTR_ERR(task);
+err:
+	xenvif_disconnect_queue(queue);
+	return err;
+}
+
+void xenvif_carrier_off(struct xenvif *vif)
+{
+	struct net_device *dev = vif->dev;
+
+	rtnl_lock();
+	if (test_and_clear_bit(VIF_STATUS_CONNECTED, &vif->status)) {
+		netif_carrier_off(dev); /* discard queued packets */
+		if (netif_running(dev))
+			xenvif_down(vif);
+	}
+	rtnl_unlock();
+}
+
+void xenvif_disconnect_data(struct xenvif *vif)
+{
+	struct xenvif_queue *queue = NULL;
+	unsigned int num_queues = vif->num_queues;
+	unsigned int queue_index;
+
+	xenvif_carrier_off(vif);
+
+	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
+		queue = &vif->queues[queue_index];
+
+		xenvif_disconnect_queue(queue);
+	}
+
+	xenvif_mcast_addr_list_free(vif);
+}
+
+void xenvif_disconnect_ctrl(struct xenvif *vif)
+{
+	if (vif->ctrl_irq) {
+		xenvif_deinit_hash(vif);
+		unbind_from_irqhandler(vif->ctrl_irq, vif);
+		vif->ctrl_irq = 0;
+	}
+
+	if (vif->ctrl.sring) {
+		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
+					vif->ctrl.sring);
+		vif->ctrl.sring = NULL;
+	}
+}
+
+/* Reverse the relevant parts of xenvif_init_queue().
+ * Used for queue teardown from xenvif_free(), and on the
+ * error handling paths in xenbus.c:connect().
+ */
+void xenvif_deinit_queue(struct xenvif_queue *queue)
+{
+	gnttab_free_pages(MAX_PENDING_REQS, queue->mmap_pages);
+}
+
+void xenvif_free(struct xenvif *vif)
+{
+	struct xenvif_queue *queues = vif->queues;
+	unsigned int num_queues = vif->num_queues;
+	unsigned int queue_index;
+
+	unregister_netdev(vif->dev);
+	free_netdev(vif->dev);
+
+	for (queue_index = 0; queue_index < num_queues; ++queue_index)
+		xenvif_deinit_queue(&queues[queue_index]);
+	vfree(queues);
+
+	module_put(THIS_MODULE);
+}