Initial import

1 files changed, 2041 insertions, 0 deletions

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
new file mode 100644
index 000000000..63c7810e1
--- /dev/null
+++ b/drivers/net/virtio_net.c
@@ -0,0 +1,2041 @@
+/* A network driver using virtio.
+ *
+ * Copyright 2007 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+//#define DEBUG
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/ethtool.h>
+#include <linux/module.h>
+#include <linux/virtio.h>
+#include <linux/virtio_net.h>
+#include <linux/scatterlist.h>
+#include <linux/if_vlan.h>
+#include <linux/slab.h>
+#include <linux/cpu.h>
+#include <linux/average.h>
+#include <net/busy_poll.h>
+
+static int napi_weight = NAPI_POLL_WEIGHT;
+module_param(napi_weight, int, 0444);
+
+static bool csum = true, gso = true;
+module_param(csum, bool, 0444);
+module_param(gso, bool, 0444);
+
+/* FIXME: MTU in config. */
+#define GOOD_PACKET_LEN (ETH_HLEN + VLAN_HLEN + ETH_DATA_LEN)
+#define GOOD_COPY_LEN	128
+
+/* Weight used for the RX packet size EWMA. The average packet size is used to
+ * determine the packet buffer size when refilling RX rings. As the entire RX
+ * ring may be refilled at once, the weight is chosen so that the EWMA will be
+ * insensitive to short-term, transient changes in packet size.
+ */
+#define RECEIVE_AVG_WEIGHT 64
+
+/* Minimum alignment for mergeable packet buffers. */
+#define MERGEABLE_BUFFER_ALIGN max(L1_CACHE_BYTES, 256)
+
+#define VIRTNET_DRIVER_VERSION "1.0.0"
+
+struct virtnet_stats {
+	struct u64_stats_sync tx_syncp;
+	struct u64_stats_sync rx_syncp;
+	u64 tx_bytes;
+	u64 tx_packets;
+
+	u64 rx_bytes;
+	u64 rx_packets;
+};
+
+/* Internal representation of a send virtqueue */
+struct send_queue {
+	/* Virtqueue associated with this send _queue */
+	struct virtqueue *vq;
+
+	/* TX: fragments + linear part + virtio header */
+	struct scatterlist sg[MAX_SKB_FRAGS + 2];
+
+	/* Name of the send queue: output.$index */
+	char name[40];
+};
+
+/* Internal representation of a receive virtqueue */
+struct receive_queue {
+	/* Virtqueue associated with this receive_queue */
+	struct virtqueue *vq;
+
+	struct napi_struct napi;
+
+	/* Chain pages by the private ptr. */
+	struct page *pages;
+
+	/* Average packet length for mergeable receive buffers. */
+	struct ewma mrg_avg_pkt_len;
+
+	/* Page frag for packet buffer allocation. */
+	struct page_frag alloc_frag;
+
+	/* RX: fragments + linear part + virtio header */
+	struct scatterlist sg[MAX_SKB_FRAGS + 2];
+
+	/* Name of this receive queue: input.$index */
+	char name[40];
+};
+
+struct virtnet_info {
+	struct virtio_device *vdev;
+	struct virtqueue *cvq;
+	struct net_device *dev;
+	struct send_queue *sq;
+	struct receive_queue *rq;
+	unsigned int status;
+
+	/* Max # of queue pairs supported by the device */
+	u16 max_queue_pairs;
+
+	/* # of queue pairs currently used by the driver */
+	u16 curr_queue_pairs;
+
+	/* I like... big packets and I cannot lie! */
+	bool big_packets;
+
+	/* Host will merge rx buffers for big packets (shake it! shake it!) */
+	bool mergeable_rx_bufs;
+
+	/* Has control virtqueue */
+	bool has_cvq;
+
+	/* Host can handle any s/g split between our header and packet data */
+	bool any_header_sg;
+
+	/* Packet virtio header size */
+	u8 hdr_len;
+
+	/* Active statistics */
+	struct virtnet_stats __percpu *stats;
+
+	/* Work struct for refilling if we run low on memory. */
+	struct delayed_work refill;
+
+	/* Work struct for config space updates */
+	struct work_struct config_work;
+
+	/* Does the affinity hint is set for virtqueues? */
+	bool affinity_hint_set;
+
+	/* CPU hot plug notifier */
+	struct notifier_block nb;
+};
+
+struct padded_vnet_hdr {
+	struct virtio_net_hdr_mrg_rxbuf hdr;
+	/*
+	 * hdr is in a separate sg buffer, and data sg buffer shares same page
+	 * with this header sg. This padding makes next sg 16 byte aligned
+	 * after the header.
+	 */
+	char padding[4];
+};
+
+/* Converting between virtqueue no. and kernel tx/rx queue no.
+ * 0:rx0 1:tx0 2:rx1 3:tx1 ... 2N:rxN 2N+1:txN 2N+2:cvq
+ */
+static int vq2txq(struct virtqueue *vq)
+{
+	return (vq->index - 1) / 2;
+}
+
+static int txq2vq(int txq)
+{
+	return txq * 2 + 1;
+}
+
+static int vq2rxq(struct virtqueue *vq)
+{
+	return vq->index / 2;
+}
+
+static int rxq2vq(int rxq)
+{
+	return rxq * 2;
+}
+
+static inline struct virtio_net_hdr_mrg_rxbuf *skb_vnet_hdr(struct sk_buff *skb)
+{
+	return (struct virtio_net_hdr_mrg_rxbuf *)skb->cb;
+}
+
+/*
+ * private is used to chain pages for big packets, put the whole
+ * most recent used list in the beginning for reuse
+ */
+static void give_pages(struct receive_queue *rq, struct page *page)
+{
+	struct page *end;
+
+	/* Find end of list, sew whole thing into vi->rq.pages. */
+	for (end = page; end->private; end = (struct page *)end->private);
+	end->private = (unsigned long)rq->pages;
+	rq->pages = page;
+}
+
+static struct page *get_a_page(struct receive_queue *rq, gfp_t gfp_mask)
+{
+	struct page *p = rq->pages;
+
+	if (p) {
+		rq->pages = (struct page *)p->private;
+		/* clear private here, it is used to chain pages */
+		p->private = 0;
+	} else
+		p = alloc_page(gfp_mask);
+	return p;
+}
+
+static void skb_xmit_done(struct virtqueue *vq)
+{
+	struct virtnet_info *vi = vq->vdev->priv;
+
+	/* Suppress further interrupts. */
+	virtqueue_disable_cb(vq);
+
+	/* We were probably waiting for more output buffers. */
+	netif_wake_subqueue(vi->dev, vq2txq(vq));
+}
+
+static unsigned int mergeable_ctx_to_buf_truesize(unsigned long mrg_ctx)
+{
+	unsigned int truesize = mrg_ctx & (MERGEABLE_BUFFER_ALIGN - 1);
+	return (truesize + 1) * MERGEABLE_BUFFER_ALIGN;
+}
+
+static void *mergeable_ctx_to_buf_address(unsigned long mrg_ctx)
+{
+	return (void *)(mrg_ctx & -MERGEABLE_BUFFER_ALIGN);
+
+}
+
+static unsigned long mergeable_buf_to_ctx(void *buf, unsigned int truesize)
+{
+	unsigned int size = truesize / MERGEABLE_BUFFER_ALIGN;
+	return (unsigned long)buf | (size - 1);
+}
+
+/* Called from bottom half context */
+static struct sk_buff *page_to_skb(struct virtnet_info *vi,
+				   struct receive_queue *rq,
+				   struct page *page, unsigned int offset,
+				   unsigned int len, unsigned int truesize)
+{
+	struct sk_buff *skb;
+	struct virtio_net_hdr_mrg_rxbuf *hdr;
+	unsigned int copy, hdr_len, hdr_padded_len;
+	char *p;
+
+	p = page_address(page) + offset;
+
+	/* copy small packet so we can reuse these pages for small data */
+	skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN);
+	if (unlikely(!skb))
+		return NULL;
+
+	hdr = skb_vnet_hdr(skb);
+
+	hdr_len = vi->hdr_len;
+	if (vi->mergeable_rx_bufs)
+		hdr_padded_len = sizeof *hdr;
+	else
+		hdr_padded_len = sizeof(struct padded_vnet_hdr);
+
+	memcpy(hdr, p, hdr_len);
+
+	len -= hdr_len;
+	offset += hdr_padded_len;
+	p += hdr_padded_len;
+
+	copy = len;
+	if (copy > skb_tailroom(skb))
+		copy = skb_tailroom(skb);
+	memcpy(skb_put(skb, copy), p, copy);
+
+	len -= copy;
+	offset += copy;
+
+	if (vi->mergeable_rx_bufs) {
+		if (len)
+			skb_add_rx_frag(skb, 0, page, offset, len, truesize);
+		else
+			put_page(page);
+		return skb;
+	}
+
+	/*
+	 * Verify that we can indeed put this data into a skb.
+	 * This is here to handle cases when the device erroneously
+	 * tries to receive more than is possible. This is usually
+	 * the case of a broken device.
+	 */
+	if (unlikely(len > MAX_SKB_FRAGS * PAGE_SIZE)) {
+		net_dbg_ratelimited("%s: too much data\n", skb->dev->name);
+		dev_kfree_skb(skb);
+		return NULL;
+	}
+	BUG_ON(offset >= PAGE_SIZE);
+	while (len) {
+		unsigned int frag_size = min((unsigned)PAGE_SIZE - offset, len);
+		skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page, offset,
+				frag_size, truesize);
+		len -= frag_size;
+		page = (struct page *)page->private;
+		offset = 0;
+	}
+
+	if (page)
+		give_pages(rq, page);
+
+	return skb;
+}
+
+static struct sk_buff *receive_small(struct virtnet_info *vi, void *buf, unsigned int len)
+{
+	struct sk_buff * skb = buf;
+
+	len -= vi->hdr_len;
+	skb_trim(skb, len);
+
+	return skb;
+}
+
+static struct sk_buff *receive_big(struct net_device *dev,
+				   struct virtnet_info *vi,
+				   struct receive_queue *rq,
+				   void *buf,
+				   unsigned int len)
+{
+	struct page *page = buf;
+	struct sk_buff *skb = page_to_skb(vi, rq, page, 0, len, PAGE_SIZE);
+
+	if (unlikely(!skb))
+		goto err;
+
+	return skb;
+
+err:
+	dev->stats.rx_dropped++;
+	give_pages(rq, page);
+	return NULL;
+}
+
+static struct sk_buff *receive_mergeable(struct net_device *dev,
+					 struct virtnet_info *vi,
+					 struct receive_queue *rq,
+					 unsigned long ctx,
+					 unsigned int len)
+{
+	void *buf = mergeable_ctx_to_buf_address(ctx);
+	struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
+	u16 num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
+	struct page *page = virt_to_head_page(buf);
+	int offset = buf - page_address(page);
+	unsigned int truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
+
+	struct sk_buff *head_skb = page_to_skb(vi, rq, page, offset, len,
+					       truesize);
+	struct sk_buff *curr_skb = head_skb;
+
+	if (unlikely(!curr_skb))
+		goto err_skb;
+	while (--num_buf) {
+		int num_skb_frags;
+
+		ctx = (unsigned long)virtqueue_get_buf(rq->vq, &len);
+		if (unlikely(!ctx)) {
+			pr_debug("%s: rx error: %d buffers out of %d missing\n",
+				 dev->name, num_buf,
+				 virtio16_to_cpu(vi->vdev,
+						 hdr->num_buffers));
+			dev->stats.rx_length_errors++;
+			goto err_buf;
+		}
+
+		buf = mergeable_ctx_to_buf_address(ctx);
+		page = virt_to_head_page(buf);
+
+		num_skb_frags = skb_shinfo(curr_skb)->nr_frags;
+		if (unlikely(num_skb_frags == MAX_SKB_FRAGS)) {
+			struct sk_buff *nskb = alloc_skb(0, GFP_ATOMIC);
+
+			if (unlikely(!nskb))
+				goto err_skb;
+			if (curr_skb == head_skb)
+				skb_shinfo(curr_skb)->frag_list = nskb;
+			else
+				curr_skb->next = nskb;
+			curr_skb = nskb;
+			head_skb->truesize += nskb->truesize;
+			num_skb_frags = 0;
+		}
+		truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
+		if (curr_skb != head_skb) {
+			head_skb->data_len += len;
+			head_skb->len += len;
+			head_skb->truesize += truesize;
+		}
+		offset = buf - page_address(page);
+		if (skb_can_coalesce(curr_skb, num_skb_frags, page, offset)) {
+			put_page(page);
+			skb_coalesce_rx_frag(curr_skb, num_skb_frags - 1,
+					     len, truesize);
+		} else {
+			skb_add_rx_frag(curr_skb, num_skb_frags, page,
+					offset, len, truesize);
+		}
+	}
+
+	ewma_add(&rq->mrg_avg_pkt_len, head_skb->len);
+	return head_skb;
+
+err_skb:
+	put_page(page);
+	while (--num_buf) {
+		ctx = (unsigned long)virtqueue_get_buf(rq->vq, &len);
+		if (unlikely(!ctx)) {
+			pr_debug("%s: rx error: %d buffers missing\n",
+				 dev->name, num_buf);
+			dev->stats.rx_length_errors++;
+			break;
+		}
+		page = virt_to_head_page(mergeable_ctx_to_buf_address(ctx));
+		put_page(page);
+	}
+err_buf:
+	dev->stats.rx_dropped++;
+	dev_kfree_skb(head_skb);
+	return NULL;
+}
+
+static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
+			void *buf, unsigned int len)
+{
+	struct net_device *dev = vi->dev;
+	struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
+	struct sk_buff *skb;
+	struct virtio_net_hdr_mrg_rxbuf *hdr;
+
+	if (unlikely(len < vi->hdr_len + ETH_HLEN)) {
+		pr_debug("%s: short packet %i\n", dev->name, len);
+		dev->stats.rx_length_errors++;
+		if (vi->mergeable_rx_bufs) {
+			unsigned long ctx = (unsigned long)buf;
+			void *base = mergeable_ctx_to_buf_address(ctx);
+			put_page(virt_to_head_page(base));
+		} else if (vi->big_packets) {
+			give_pages(rq, buf);
+		} else {
+			dev_kfree_skb(buf);
+		}
+		return;
+	}
+
+	if (vi->mergeable_rx_bufs)
+		skb = receive_mergeable(dev, vi, rq, (unsigned long)buf, len);
+	else if (vi->big_packets)
+		skb = receive_big(dev, vi, rq, buf, len);
+	else
+		skb = receive_small(vi, buf, len);
+
+	if (unlikely(!skb))
+		return;
+
+	hdr = skb_vnet_hdr(skb);
+
+	u64_stats_update_begin(&stats->rx_syncp);
+	stats->rx_bytes += skb->len;
+	stats->rx_packets++;
+	u64_stats_update_end(&stats->rx_syncp);
+
+	if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
+		pr_debug("Needs csum!\n");
+		if (!skb_partial_csum_set(skb,
+			  virtio16_to_cpu(vi->vdev, hdr->hdr.csum_start),
+			  virtio16_to_cpu(vi->vdev, hdr->hdr.csum_offset)))
+			goto frame_err;
+	} else if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID) {
+		skb->ip_summed = CHECKSUM_UNNECESSARY;
+	}
+
+	skb->protocol = eth_type_trans(skb, dev);
+	pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
+		 ntohs(skb->protocol), skb->len, skb->pkt_type);
+
+	if (hdr->hdr.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
+		pr_debug("GSO!\n");
+		switch (hdr->hdr.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
+		case VIRTIO_NET_HDR_GSO_TCPV4:
+			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
+			break;
+		case VIRTIO_NET_HDR_GSO_UDP:
+			skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
+			break;
+		case VIRTIO_NET_HDR_GSO_TCPV6:
+			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
+			break;
+		default:
+			net_warn_ratelimited("%s: bad gso type %u.\n",
+					     dev->name, hdr->hdr.gso_type);
+			goto frame_err;
+		}
+
+		if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
+			skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
+
+		skb_shinfo(skb)->gso_size = virtio16_to_cpu(vi->vdev,
+							    hdr->hdr.gso_size);
+		if (skb_shinfo(skb)->gso_size == 0) {
+			net_warn_ratelimited("%s: zero gso size.\n", dev->name);
+			goto frame_err;
+		}
+
+		/* Header must be checked, and gso_segs computed. */
+		skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
+		skb_shinfo(skb)->gso_segs = 0;
+	}
+
+	skb_mark_napi_id(skb, &rq->napi);
+
+	netif_receive_skb(skb);
+	return;
+
+frame_err:
+	dev->stats.rx_frame_errors++;
+	dev_kfree_skb(skb);
+}
+
+static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq,
+			     gfp_t gfp)
+{
+	struct sk_buff *skb;
+	struct virtio_net_hdr_mrg_rxbuf *hdr;
+	int err;
+
+	skb = __netdev_alloc_skb_ip_align(vi->dev, GOOD_PACKET_LEN, gfp);
+	if (unlikely(!skb))
+		return -ENOMEM;
+
+	skb_put(skb, GOOD_PACKET_LEN);
+
+	hdr = skb_vnet_hdr(skb);
+	sg_init_table(rq->sg, MAX_SKB_FRAGS + 2);
+	sg_set_buf(rq->sg, hdr, vi->hdr_len);
+	skb_to_sgvec(skb, rq->sg + 1, 0, skb->len);
+
+	err = virtqueue_add_inbuf(rq->vq, rq->sg, 2, skb, gfp);
+	if (err < 0)
+		dev_kfree_skb(skb);
+
+	return err;
+}
+
+static int add_recvbuf_big(struct virtnet_info *vi, struct receive_queue *rq,
+			   gfp_t gfp)
+{
+	struct page *first, *list = NULL;
+	char *p;
+	int i, err, offset;
+
+	sg_init_table(rq->sg, MAX_SKB_FRAGS + 2);
+
+	/* page in rq->sg[MAX_SKB_FRAGS + 1] is list tail */
+	for (i = MAX_SKB_FRAGS + 1; i > 1; --i) {
+		first = get_a_page(rq, gfp);
+		if (!first) {
+			if (list)
+				give_pages(rq, list);
+			return -ENOMEM;
+		}
+		sg_set_buf(&rq->sg[i], page_address(first), PAGE_SIZE);
+
+		/* chain new page in list head to match sg */
+		first->private = (unsigned long)list;
+		list = first;
+	}
+
+	first = get_a_page(rq, gfp);
+	if (!first) {
+		give_pages(rq, list);
+		return -ENOMEM;
+	}
+	p = page_address(first);
+
+	/* rq->sg[0], rq->sg[1] share the same page */
+	/* a separated rq->sg[0] for header - required in case !any_header_sg */
+	sg_set_buf(&rq->sg[0], p, vi->hdr_len);
+
+	/* rq->sg[1] for data packet, from offset */
+	offset = sizeof(struct padded_vnet_hdr);
+	sg_set_buf(&rq->sg[1], p + offset, PAGE_SIZE - offset);
+
+	/* chain first in list head */
+	first->private = (unsigned long)list;
+	err = virtqueue_add_inbuf(rq->vq, rq->sg, MAX_SKB_FRAGS + 2,
+				  first, gfp);
+	if (err < 0)
+		give_pages(rq, first);
+
+	return err;
+}
+
+static unsigned int get_mergeable_buf_len(struct ewma *avg_pkt_len)
+{
+	const size_t hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
+	unsigned int len;
+
+	len = hdr_len + clamp_t(unsigned int, ewma_read(avg_pkt_len),
+			GOOD_PACKET_LEN, PAGE_SIZE - hdr_len);
+	return ALIGN(len, MERGEABLE_BUFFER_ALIGN);
+}
+
+static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp)
+{
+	struct page_frag *alloc_frag = &rq->alloc_frag;
+	char *buf;
+	unsigned long ctx;
+	int err;
+	unsigned int len, hole;
+
+	len = get_mergeable_buf_len(&rq->mrg_avg_pkt_len);
+	if (unlikely(!skb_page_frag_refill(len, alloc_frag, gfp)))
+		return -ENOMEM;
+
+	buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
+	ctx = mergeable_buf_to_ctx(buf, len);
+	get_page(alloc_frag->page);
+	alloc_frag->offset += len;
+	hole = alloc_frag->size - alloc_frag->offset;
+	if (hole < len) {
+		/* To avoid internal fragmentation, if there is very likely not
+		 * enough space for another buffer, add the remaining space to
+		 * the current buffer. This extra space is not included in
+		 * the truesize stored in ctx.
+		 */
+		len += hole;
+		alloc_frag->offset += hole;
+	}
+
+	sg_init_one(rq->sg, buf, len);
+	err = virtqueue_add_inbuf(rq->vq, rq->sg, 1, (void *)ctx, gfp);
+	if (err < 0)
+		put_page(virt_to_head_page(buf));
+
+	return err;
+}
+
+/*
+ * Returns false if we couldn't fill entirely (OOM).
+ *
+ * Normally run in the receive path, but can also be run from ndo_open
+ * before we're receiving packets, or from refill_work which is
+ * careful to disable receiving (using napi_disable).
+ */
+static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq,
+			  gfp_t gfp)
+{
+	int err;
+	bool oom;
+
+	gfp |= __GFP_COLD;
+	do {
+		if (vi->mergeable_rx_bufs)
+			err = add_recvbuf_mergeable(rq, gfp);
+		else if (vi->big_packets)
+			err = add_recvbuf_big(vi, rq, gfp);
+		else
+			err = add_recvbuf_small(vi, rq, gfp);
+
+		oom = err == -ENOMEM;
+		if (err)
+			break;
+	} while (rq->vq->num_free);
+	virtqueue_kick(rq->vq);
+	return !oom;
+}
+
+static void skb_recv_done(struct virtqueue *rvq)
+{
+	struct virtnet_info *vi = rvq->vdev->priv;
+	struct receive_queue *rq = &vi->rq[vq2rxq(rvq)];
+
+	/* Schedule NAPI, Suppress further interrupts if successful. */
+	if (napi_schedule_prep(&rq->napi)) {
+		virtqueue_disable_cb(rvq);
+		__napi_schedule(&rq->napi);
+	}
+}
+
+static void virtnet_napi_enable(struct receive_queue *rq)
+{
+	napi_enable(&rq->napi);
+
+	/* If all buffers were filled by other side before we napi_enabled, we
+	 * won't get another interrupt, so process any outstanding packets
+	 * now.  virtnet_poll wants re-enable the queue, so we disable here.
+	 * We synchronize against interrupts via NAPI_STATE_SCHED */
+	if (napi_schedule_prep(&rq->napi)) {
+		virtqueue_disable_cb(rq->vq);
+		local_bh_disable();
+		__napi_schedule(&rq->napi);
+		local_bh_enable();
+	}
+}
+
+static void refill_work(struct work_struct *work)
+{
+	struct virtnet_info *vi =
+		container_of(work, struct virtnet_info, refill.work);
+	bool still_empty;
+	int i;
+
+	for (i = 0; i < vi->curr_queue_pairs; i++) {
+		struct receive_queue *rq = &vi->rq[i];
+
+		napi_disable(&rq->napi);
+		still_empty = !try_fill_recv(vi, rq, GFP_KERNEL);
+		virtnet_napi_enable(rq);
+
+		/* In theory, this can happen: if we don't get any buffers in
+		 * we will *never* try to fill again.
+		 */
+		if (still_empty)
+			schedule_delayed_work(&vi->refill, HZ/2);
+	}
+}
+
+static int virtnet_receive(struct receive_queue *rq, int budget)
+{
+	struct virtnet_info *vi = rq->vq->vdev->priv;
+	unsigned int len, received = 0;
+	void *buf;
+
+	while (received < budget &&
+	       (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {
+		receive_buf(vi, rq, buf, len);
+		received++;
+	}
+
+	if (rq->vq->num_free > virtqueue_get_vring_size(rq->vq) / 2) {
+		if (!try_fill_recv(vi, rq, GFP_ATOMIC))
+			schedule_delayed_work(&vi->refill, 0);
+	}
+
+	return received;
+}
+
+static int virtnet_poll(struct napi_struct *napi, int budget)
+{
+	struct receive_queue *rq =
+		container_of(napi, struct receive_queue, napi);
+	unsigned int r, received;
+
+	received = virtnet_receive(rq, budget);
+
+	/* Out of packets? */
+	if (received < budget) {
+		r = virtqueue_enable_cb_prepare(rq->vq);
+		napi_complete(napi);
+		if (unlikely(virtqueue_poll(rq->vq, r)) &&
+		    napi_schedule_prep(napi)) {
+			virtqueue_disable_cb(rq->vq);
+			__napi_schedule(napi);
+		}
+	}
+
+	return received;
+}
+
+#ifdef CONFIG_NET_RX_BUSY_POLL
+/* must be called with local_bh_disable()d */
+static int virtnet_busy_poll(struct napi_struct *napi)
+{
+	struct receive_queue *rq =
+		container_of(napi, struct receive_queue, napi);
+	struct virtnet_info *vi = rq->vq->vdev->priv;
+	int r, received = 0, budget = 4;
+
+	if (!(vi->status & VIRTIO_NET_S_LINK_UP))
+		return LL_FLUSH_FAILED;
+
+	if (!napi_schedule_prep(napi))
+		return LL_FLUSH_BUSY;
+
+	virtqueue_disable_cb(rq->vq);
+
+again:
+	received += virtnet_receive(rq, budget);
+
+	r = virtqueue_enable_cb_prepare(rq->vq);
+	clear_bit(NAPI_STATE_SCHED, &napi->state);
+	if (unlikely(virtqueue_poll(rq->vq, r)) &&
+	    napi_schedule_prep(napi)) {
+		virtqueue_disable_cb(rq->vq);
+		if (received < budget) {
+			budget -= received;
+			goto again;
+		} else {
+			__napi_schedule(napi);
+		}
+	}
+
+	return received;
+}
+#endif	/* CONFIG_NET_RX_BUSY_POLL */
+
+static int virtnet_open(struct net_device *dev)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	int i;
+
+	for (i = 0; i < vi->max_queue_pairs; i++) {
+		if (i < vi->curr_queue_pairs)
+			/* Make sure we have some buffers: if oom use wq. */
+			if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
+				schedule_delayed_work(&vi->refill, 0);
+		virtnet_napi_enable(&vi->rq[i]);
+	}
+
+	return 0;
+}
+
+static void free_old_xmit_skbs(struct send_queue *sq)
+{
+	struct sk_buff *skb;
+	unsigned int len;
+	struct virtnet_info *vi = sq->vq->vdev->priv;
+	struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
+
+	while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) {
+		pr_debug("Sent skb %p\n", skb);
+
+		u64_stats_update_begin(&stats->tx_syncp);
+		stats->tx_bytes += skb->len;
+		stats->tx_packets++;
+		u64_stats_update_end(&stats->tx_syncp);
+
+		dev_kfree_skb_any(skb);
+	}
+}
+
+static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
+{
+	struct virtio_net_hdr_mrg_rxbuf *hdr;
+	const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
+	struct virtnet_info *vi = sq->vq->vdev->priv;
+	unsigned num_sg;
+	unsigned hdr_len = vi->hdr_len;
+	bool can_push;
+
+	pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
+
+	can_push = vi->any_header_sg &&
+		!((unsigned long)skb->data & (__alignof__(*hdr) - 1)) &&
+		!skb_header_cloned(skb) && skb_headroom(skb) >= hdr_len;
+	/* Even if we can, don't push here yet as this would skew
+	 * csum_start offset below. */
+	if (can_push)
+		hdr = (struct virtio_net_hdr_mrg_rxbuf *)(skb->data - hdr_len);
+	else
+		hdr = skb_vnet_hdr(skb);
+
+	if (skb->ip_summed == CHECKSUM_PARTIAL) {
+		hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
+		hdr->hdr.csum_start = cpu_to_virtio16(vi->vdev,
+						skb_checksum_start_offset(skb));
+		hdr->hdr.csum_offset = cpu_to_virtio16(vi->vdev,
+							 skb->csum_offset);
+	} else {
+		hdr->hdr.flags = 0;
+		hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
+	}
+
+	if (skb_is_gso(skb)) {
+		hdr->hdr.hdr_len = cpu_to_virtio16(vi->vdev, skb_headlen(skb));
+		hdr->hdr.gso_size = cpu_to_virtio16(vi->vdev,
+						    skb_shinfo(skb)->gso_size);
+		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
+			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
+		else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
+			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
+		else if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
+			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_UDP;
+		else
+			BUG();
+		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_ECN)
+			hdr->hdr.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
+	} else {
+		hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
+		hdr->hdr.gso_size = hdr->hdr.hdr_len = 0;
+	}
+
+	if (vi->mergeable_rx_bufs)
+		hdr->num_buffers = 0;
+
+	sg_init_table(sq->sg, MAX_SKB_FRAGS + 2);
+	if (can_push) {
+		__skb_push(skb, hdr_len);
+		num_sg = skb_to_sgvec(skb, sq->sg, 0, skb->len);
+		/* Pull header back to avoid skew in tx bytes calculations. */
+		__skb_pull(skb, hdr_len);
+	} else {
+		sg_set_buf(sq->sg, hdr, hdr_len);
+		num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1;
+	}
+	return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, GFP_ATOMIC);
+}
+
+static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	int qnum = skb_get_queue_mapping(skb);
+	struct send_queue *sq = &vi->sq[qnum];
+	int err;
+	struct netdev_queue *txq = netdev_get_tx_queue(dev, qnum);
+	bool kick = !skb->xmit_more;
+
+	/* Free up any pending old buffers before queueing new ones. */
+	free_old_xmit_skbs(sq);
+
+	/* timestamp packet in software */
+	skb_tx_timestamp(skb);
+
+	/* Try to transmit */
+	err = xmit_skb(sq, skb);
+
+	/* This should not happen! */
+	if (unlikely(err)) {
+		dev->stats.tx_fifo_errors++;
+		if (net_ratelimit())
+			dev_warn(&dev->dev,
+				 "Unexpected TXQ (%d) queue failure: %d\n", qnum, err);
+		dev->stats.tx_dropped++;
+		dev_kfree_skb_any(skb);
+		return NETDEV_TX_OK;
+	}
+
+	/* Don't wait up for transmitted skbs to be freed. */
+	skb_orphan(skb);
+	nf_reset(skb);
+
+	/* If running out of space, stop queue to avoid getting packets that we
+	 * are then unable to transmit.
+	 * An alternative would be to force queuing layer to requeue the skb by
+	 * returning NETDEV_TX_BUSY. However, NETDEV_TX_BUSY should not be
+	 * returned in a normal path of operation: it means that driver is not
+	 * maintaining the TX queue stop/start state properly, and causes
+	 * the stack to do a non-trivial amount of useless work.
+	 * Since most packets only take 1 or 2 ring slots, stopping the queue
+	 * early means 16 slots are typically wasted.
+	 */
+	if (sq->vq->num_free < 2+MAX_SKB_FRAGS) {
+		netif_stop_subqueue(dev, qnum);
+		if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
+			/* More just got used, free them then recheck. */
+			free_old_xmit_skbs(sq);
+			if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
+				netif_start_subqueue(dev, qnum);
+				virtqueue_disable_cb(sq->vq);
+			}
+		}
+	}
+
+	if (kick || netif_xmit_stopped(txq))
+		virtqueue_kick(sq->vq);
+
+	return NETDEV_TX_OK;
+}
+
+/*
+ * Send command via the control virtqueue and check status.  Commands
+ * supported by the hypervisor, as indicated by feature bits, should
+ * never fail unless improperly formatted.
+ */
+static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
+				 struct scatterlist *out)
+{
+	struct scatterlist *sgs[4], hdr, stat;
+	struct virtio_net_ctrl_hdr ctrl;
+	virtio_net_ctrl_ack status = ~0;
+	unsigned out_num = 0, tmp;
+
+	/* Caller should know better */
+	BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ));
+
+	ctrl.class = class;
+	ctrl.cmd = cmd;
+	/* Add header */
+	sg_init_one(&hdr, &ctrl, sizeof(ctrl));
+	sgs[out_num++] = &hdr;
+
+	if (out)
+		sgs[out_num++] = out;
+
+	/* Add return status. */
+	sg_init_one(&stat, &status, sizeof(status));
+	sgs[out_num] = &stat;
+
+	BUG_ON(out_num + 1 > ARRAY_SIZE(sgs));
+	virtqueue_add_sgs(vi->cvq, sgs, out_num, 1, vi, GFP_ATOMIC);
+
+	if (unlikely(!virtqueue_kick(vi->cvq)))
+		return status == VIRTIO_NET_OK;
+
+	/* Spin for a response, the kick causes an ioport write, trapping
+	 * into the hypervisor, so the request should be handled immediately.
+	 */
+	while (!virtqueue_get_buf(vi->cvq, &tmp) &&
+	       !virtqueue_is_broken(vi->cvq))
+		cpu_relax();
+
+	return status == VIRTIO_NET_OK;
+}
+
+static int virtnet_set_mac_address(struct net_device *dev, void *p)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	struct virtio_device *vdev = vi->vdev;
+	int ret;
+	struct sockaddr *addr = p;
+	struct scatterlist sg;
+
+	ret = eth_prepare_mac_addr_change(dev, p);
+	if (ret)
+		return ret;
+
+	if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR)) {
+		sg_init_one(&sg, addr->sa_data, dev->addr_len);
+		if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
+					  VIRTIO_NET_CTRL_MAC_ADDR_SET, &sg)) {
+			dev_warn(&vdev->dev,
+				 "Failed to set mac address by vq command.\n");
+			return -EINVAL;
+		}
+	} else if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC) &&
+		   !virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) {
+		unsigned int i;
+
+		/* Naturally, this has an atomicity problem. */
+		for (i = 0; i < dev->addr_len; i++)
+			virtio_cwrite8(vdev,
+				       offsetof(struct virtio_net_config, mac) +
+				       i, addr->sa_data[i]);
+	}
+
+	eth_commit_mac_addr_change(dev, p);
+
+	return 0;
+}
+
+static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
+					       struct rtnl_link_stats64 *tot)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	int cpu;
+	unsigned int start;
+
+	for_each_possible_cpu(cpu) {
+		struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu);
+		u64 tpackets, tbytes, rpackets, rbytes;
+
+		do {
+			start = u64_stats_fetch_begin_irq(&stats->tx_syncp);
+			tpackets = stats->tx_packets;
+			tbytes   = stats->tx_bytes;
+		} while (u64_stats_fetch_retry_irq(&stats->tx_syncp, start));
+
+		do {
+			start = u64_stats_fetch_begin_irq(&stats->rx_syncp);
+			rpackets = stats->rx_packets;
+			rbytes   = stats->rx_bytes;
+		} while (u64_stats_fetch_retry_irq(&stats->rx_syncp, start));
+
+		tot->rx_packets += rpackets;
+		tot->tx_packets += tpackets;
+		tot->rx_bytes   += rbytes;
+		tot->tx_bytes   += tbytes;
+	}
+
+	tot->tx_dropped = dev->stats.tx_dropped;
+	tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
+	tot->rx_dropped = dev->stats.rx_dropped;
+	tot->rx_length_errors = dev->stats.rx_length_errors;
+	tot->rx_frame_errors = dev->stats.rx_frame_errors;
+
+	return tot;
+}
+
+#ifdef CONFIG_NET_POLL_CONTROLLER
+static void virtnet_netpoll(struct net_device *dev)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	int i;
+
+	for (i = 0; i < vi->curr_queue_pairs; i++)
+		napi_schedule(&vi->rq[i].napi);
+}
+#endif
+
+static void virtnet_ack_link_announce(struct virtnet_info *vi)
+{
+	rtnl_lock();
+	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
+				  VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL))
+		dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
+	rtnl_unlock();
+}
+
+static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
+{
+	struct scatterlist sg;
+	struct virtio_net_ctrl_mq s;
+	struct net_device *dev = vi->dev;
+
+	if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ))
+		return 0;
+
+	s.virtqueue_pairs = cpu_to_virtio16(vi->vdev, queue_pairs);
+	sg_init_one(&sg, &s, sizeof(s));
+
+	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
+				  VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET, &sg)) {
+		dev_warn(&dev->dev, "Fail to set num of queue pairs to %d\n",
+			 queue_pairs);
+		return -EINVAL;
+	} else {
+		vi->curr_queue_pairs = queue_pairs;
+		/* virtnet_open() will refill when device is going to up. */
+		if (dev->flags & IFF_UP)
+			schedule_delayed_work(&vi->refill, 0);
+	}
+
+	return 0;
+}
+
+static int virtnet_close(struct net_device *dev)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	int i;
+
+	/* Make sure refill_work doesn't re-enable napi! */
+	cancel_delayed_work_sync(&vi->refill);
+
+	for (i = 0; i < vi->max_queue_pairs; i++)
+		napi_disable(&vi->rq[i].napi);
+
+	return 0;
+}
+
+static void virtnet_set_rx_mode(struct net_device *dev)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	struct scatterlist sg[2];
+	u8 promisc, allmulti;
+	struct virtio_net_ctrl_mac *mac_data;
+	struct netdev_hw_addr *ha;
+	int uc_count;
+	int mc_count;
+	void *buf;
+	int i;
+
+	/* We can't dynamically set ndo_set_rx_mode, so return gracefully */
+	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
+		return;
+
+	promisc = ((dev->flags & IFF_PROMISC) != 0);
+	allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
+
+	sg_init_one(sg, &promisc, sizeof(promisc));
+
+	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
+				  VIRTIO_NET_CTRL_RX_PROMISC, sg))
+		dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
+			 promisc ? "en" : "dis");
+
+	sg_init_one(sg, &allmulti, sizeof(allmulti));
+
+	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
+				  VIRTIO_NET_CTRL_RX_ALLMULTI, sg))
+		dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
+			 allmulti ? "en" : "dis");
+
+	uc_count = netdev_uc_count(dev);
+	mc_count = netdev_mc_count(dev);
+	/* MAC filter - use one buffer for both lists */
+	buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
+		      (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
+	mac_data = buf;
+	if (!buf)
+		return;
+
+	sg_init_table(sg, 2);
+
+	/* Store the unicast list and count in the front of the buffer */
+	mac_data->entries = cpu_to_virtio32(vi->vdev, uc_count);
+	i = 0;
+	netdev_for_each_uc_addr(ha, dev)
+		memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
+
+	sg_set_buf(&sg[0], mac_data,
+		   sizeof(mac_data->entries) + (uc_count * ETH_ALEN));
+
+	/* multicast list and count fill the end */
+	mac_data = (void *)&mac_data->macs[uc_count][0];
+
+	mac_data->entries = cpu_to_virtio32(vi->vdev, mc_count);
+	i = 0;
+	netdev_for_each_mc_addr(ha, dev)
+		memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
+
+	sg_set_buf(&sg[1], mac_data,
+		   sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
+
+	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
+				  VIRTIO_NET_CTRL_MAC_TABLE_SET, sg))
+		dev_warn(&dev->dev, "Failed to set MAC filter table.\n");
+
+	kfree(buf);
+}
+
+static int virtnet_vlan_rx_add_vid(struct net_device *dev,
+				   __be16 proto, u16 vid)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	struct scatterlist sg;
+
+	sg_init_one(&sg, &vid, sizeof(vid));
+
+	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
+				  VIRTIO_NET_CTRL_VLAN_ADD, &sg))
+		dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
+	return 0;
+}
+
+static int virtnet_vlan_rx_kill_vid(struct net_device *dev,
+				    __be16 proto, u16 vid)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	struct scatterlist sg;
+
+	sg_init_one(&sg, &vid, sizeof(vid));
+
+	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
+				  VIRTIO_NET_CTRL_VLAN_DEL, &sg))
+		dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
+	return 0;
+}
+
+static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
+{
+	int i;
+
+	if (vi->affinity_hint_set) {
+		for (i = 0; i < vi->max_queue_pairs; i++) {
+			virtqueue_set_affinity(vi->rq[i].vq, -1);
+			virtqueue_set_affinity(vi->sq[i].vq, -1);
+		}
+
+		vi->affinity_hint_set = false;
+	}
+}
+
+static void virtnet_set_affinity(struct virtnet_info *vi)
+{
+	int i;
+	int cpu;
+
+	/* In multiqueue mode, when the number of cpu is equal to the number of
+	 * queue pairs, we let the queue pairs to be private to one cpu by
+	 * setting the affinity hint to eliminate the contention.
+	 */
+	if (vi->curr_queue_pairs == 1 ||
+	    vi->max_queue_pairs != num_online_cpus()) {
+		virtnet_clean_affinity(vi, -1);
+		return;
+	}
+
+	i = 0;
+	for_each_online_cpu(cpu) {
+		virtqueue_set_affinity(vi->rq[i].vq, cpu);
+		virtqueue_set_affinity(vi->sq[i].vq, cpu);
+		netif_set_xps_queue(vi->dev, cpumask_of(cpu), i);
+		i++;
+	}
+
+	vi->affinity_hint_set = true;
+}
+
+static int virtnet_cpu_callback(struct notifier_block *nfb,
+			        unsigned long action, void *hcpu)
+{
+	struct virtnet_info *vi = container_of(nfb, struct virtnet_info, nb);
+
+	switch(action & ~CPU_TASKS_FROZEN) {
+	case CPU_ONLINE:
+	case CPU_DOWN_FAILED:
+	case CPU_DEAD:
+		virtnet_set_affinity(vi);
+		break;
+	case CPU_DOWN_PREPARE:
+		virtnet_clean_affinity(vi, (long)hcpu);
+		break;
+	default:
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static void virtnet_get_ringparam(struct net_device *dev,
+				struct ethtool_ringparam *ring)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+
+	ring->rx_max_pending = virtqueue_get_vring_size(vi->rq[0].vq);
+	ring->tx_max_pending = virtqueue_get_vring_size(vi->sq[0].vq);
+	ring->rx_pending = ring->rx_max_pending;
+	ring->tx_pending = ring->tx_max_pending;
+}
+
+
+static void virtnet_get_drvinfo(struct net_device *dev,
+				struct ethtool_drvinfo *info)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	struct virtio_device *vdev = vi->vdev;
+
+	strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
+	strlcpy(info->version, VIRTNET_DRIVER_VERSION, sizeof(info->version));
+	strlcpy(info->bus_info, virtio_bus_name(vdev), sizeof(info->bus_info));
+
+}
+
+/* TODO: Eliminate OOO packets during switching */
+static int virtnet_set_channels(struct net_device *dev,
+				struct ethtool_channels *channels)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	u16 queue_pairs = channels->combined_count;
+	int err;
+
+	/* We don't support separate rx/tx channels.
+	 * We don't allow setting 'other' channels.
+	 */
+	if (channels->rx_count || channels->tx_count || channels->other_count)
+		return -EINVAL;
+
+	if (queue_pairs > vi->max_queue_pairs || queue_pairs == 0)
+		return -EINVAL;
+
+	get_online_cpus();
+	err = virtnet_set_queues(vi, queue_pairs);
+	if (!err) {
+		netif_set_real_num_tx_queues(dev, queue_pairs);
+		netif_set_real_num_rx_queues(dev, queue_pairs);
+
+		virtnet_set_affinity(vi);
+	}
+	put_online_cpus();
+
+	return err;
+}
+
+static void virtnet_get_channels(struct net_device *dev,
+				 struct ethtool_channels *channels)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+
+	channels->combined_count = vi->curr_queue_pairs;
+	channels->max_combined = vi->max_queue_pairs;
+	channels->max_other = 0;
+	channels->rx_count = 0;
+	channels->tx_count = 0;
+	channels->other_count = 0;
+}
+
+static const struct ethtool_ops virtnet_ethtool_ops = {
+	.get_drvinfo = virtnet_get_drvinfo,
+	.get_link = ethtool_op_get_link,
+	.get_ringparam = virtnet_get_ringparam,
+	.set_channels = virtnet_set_channels,
+	.get_channels = virtnet_get_channels,
+	.get_ts_info = ethtool_op_get_ts_info,
+};
+
+#define MIN_MTU 68
+#define MAX_MTU 65535
+
+static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
+{
+	if (new_mtu < MIN_MTU || new_mtu > MAX_MTU)
+		return -EINVAL;
+	dev->mtu = new_mtu;
+	return 0;
+}
+
+static const struct net_device_ops virtnet_netdev = {
+	.ndo_open            = virtnet_open,
+	.ndo_stop   	     = virtnet_close,
+	.ndo_start_xmit      = start_xmit,
+	.ndo_validate_addr   = eth_validate_addr,
+	.ndo_set_mac_address = virtnet_set_mac_address,
+	.ndo_set_rx_mode     = virtnet_set_rx_mode,
+	.ndo_change_mtu	     = virtnet_change_mtu,
+	.ndo_get_stats64     = virtnet_stats,
+	.ndo_vlan_rx_add_vid = virtnet_vlan_rx_add_vid,
+	.ndo_vlan_rx_kill_vid = virtnet_vlan_rx_kill_vid,
+#ifdef CONFIG_NET_POLL_CONTROLLER
+	.ndo_poll_controller = virtnet_netpoll,
+#endif
+#ifdef CONFIG_NET_RX_BUSY_POLL
+	.ndo_busy_poll		= virtnet_busy_poll,
+#endif
+};
+
+static void virtnet_config_changed_work(struct work_struct *work)
+{
+	struct virtnet_info *vi =
+		container_of(work, struct virtnet_info, config_work);
+	u16 v;
+
+	if (virtio_cread_feature(vi->vdev, VIRTIO_NET_F_STATUS,
+				 struct virtio_net_config, status, &v) < 0)
+		return;
+
+	if (v & VIRTIO_NET_S_ANNOUNCE) {
+		netdev_notify_peers(vi->dev);
+		virtnet_ack_link_announce(vi);
+	}
+
+	/* Ignore unknown (future) status bits */
+	v &= VIRTIO_NET_S_LINK_UP;
+
+	if (vi->status == v)
+		return;
+
+	vi->status = v;
+
+	if (vi->status & VIRTIO_NET_S_LINK_UP) {
+		netif_carrier_on(vi->dev);
+		netif_tx_wake_all_queues(vi->dev);
+	} else {
+		netif_carrier_off(vi->dev);
+		netif_tx_stop_all_queues(vi->dev);
+	}
+}
+
+static void virtnet_config_changed(struct virtio_device *vdev)
+{
+	struct virtnet_info *vi = vdev->priv;
+
+	schedule_work(&vi->config_work);
+}
+
+static void virtnet_free_queues(struct virtnet_info *vi)
+{
+	int i;
+
+	for (i = 0; i < vi->max_queue_pairs; i++) {
+		napi_hash_del(&vi->rq[i].napi);
+		netif_napi_del(&vi->rq[i].napi);
+	}
+
+	kfree(vi->rq);
+	kfree(vi->sq);
+}
+
+static void free_receive_bufs(struct virtnet_info *vi)
+{
+	int i;
+
+	for (i = 0; i < vi->max_queue_pairs; i++) {
+		while (vi->rq[i].pages)
+			__free_pages(get_a_page(&vi->rq[i], GFP_KERNEL), 0);
+	}
+}
+
+static void free_receive_page_frags(struct virtnet_info *vi)
+{
+	int i;
+	for (i = 0; i < vi->max_queue_pairs; i++)
+		if (vi->rq[i].alloc_frag.page)
+			put_page(vi->rq[i].alloc_frag.page);
+}
+
+static void free_unused_bufs(struct virtnet_info *vi)
+{
+	void *buf;
+	int i;
+
+	for (i = 0; i < vi->max_queue_pairs; i++) {
+		struct virtqueue *vq = vi->sq[i].vq;
+		while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)
+			dev_kfree_skb(buf);
+	}
+
+	for (i = 0; i < vi->max_queue_pairs; i++) {
+		struct virtqueue *vq = vi->rq[i].vq;
+
+		while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
+			if (vi->mergeable_rx_bufs) {
+				unsigned long ctx = (unsigned long)buf;
+				void *base = mergeable_ctx_to_buf_address(ctx);
+				put_page(virt_to_head_page(base));
+			} else if (vi->big_packets) {
+				give_pages(&vi->rq[i], buf);
+			} else {
+				dev_kfree_skb(buf);
+			}
+		}
+	}
+}
+
+static void virtnet_del_vqs(struct virtnet_info *vi)
+{
+	struct virtio_device *vdev = vi->vdev;
+
+	virtnet_clean_affinity(vi, -1);
+
+	vdev->config->del_vqs(vdev);
+
+	virtnet_free_queues(vi);
+}
+
+static int virtnet_find_vqs(struct virtnet_info *vi)
+{
+	vq_callback_t **callbacks;
+	struct virtqueue **vqs;
+	int ret = -ENOMEM;
+	int i, total_vqs;
+	const char **names;
+
+	/* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
+	 * possible N-1 RX/TX queue pairs used in multiqueue mode, followed by
+	 * possible control vq.
+	 */
+	total_vqs = vi->max_queue_pairs * 2 +
+		    virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ);
+
+	/* Allocate space for find_vqs parameters */
+	vqs = kzalloc(total_vqs * sizeof(*vqs), GFP_KERNEL);
+	if (!vqs)
+		goto err_vq;
+	callbacks = kmalloc(total_vqs * sizeof(*callbacks), GFP_KERNEL);
+	if (!callbacks)
+		goto err_callback;
+	names = kmalloc(total_vqs * sizeof(*names), GFP_KERNEL);
+	if (!names)
+		goto err_names;
+
+	/* Parameters for control virtqueue, if any */
+	if (vi->has_cvq) {
+		callbacks[total_vqs - 1] = NULL;
+		names[total_vqs - 1] = "control";
+	}
+
+	/* Allocate/initialize parameters for send/receive virtqueues */
+	for (i = 0; i < vi->max_queue_pairs; i++) {
+		callbacks[rxq2vq(i)] = skb_recv_done;
+		callbacks[txq2vq(i)] = skb_xmit_done;
+		sprintf(vi->rq[i].name, "input.%d", i);
+		sprintf(vi->sq[i].name, "output.%d", i);
+		names[rxq2vq(i)] = vi->rq[i].name;
+		names[txq2vq(i)] = vi->sq[i].name;
+	}
+
+	ret = vi->vdev->config->find_vqs(vi->vdev, total_vqs, vqs, callbacks,
+					 names);
+	if (ret)
+		goto err_find;
+
+	if (vi->has_cvq) {
+		vi->cvq = vqs[total_vqs - 1];
+		if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
+			vi->dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
+	}
+
+	for (i = 0; i < vi->max_queue_pairs; i++) {
+		vi->rq[i].vq = vqs[rxq2vq(i)];
+		vi->sq[i].vq = vqs[txq2vq(i)];
+	}
+
+	kfree(names);
+	kfree(callbacks);
+	kfree(vqs);
+
+	return 0;
+
+err_find:
+	kfree(names);
+err_names:
+	kfree(callbacks);
+err_callback:
+	kfree(vqs);
+err_vq:
+	return ret;
+}
+
+static int virtnet_alloc_queues(struct virtnet_info *vi)
+{
+	int i;
+
+	vi->sq = kzalloc(sizeof(*vi->sq) * vi->max_queue_pairs, GFP_KERNEL);
+	if (!vi->sq)
+		goto err_sq;
+	vi->rq = kzalloc(sizeof(*vi->rq) * vi->max_queue_pairs, GFP_KERNEL);
+	if (!vi->rq)
+		goto err_rq;
+
+	INIT_DELAYED_WORK(&vi->refill, refill_work);
+	for (i = 0; i < vi->max_queue_pairs; i++) {
+		vi->rq[i].pages = NULL;
+		netif_napi_add(vi->dev, &vi->rq[i].napi, virtnet_poll,
+			       napi_weight);
+		napi_hash_add(&vi->rq[i].napi);
+
+		sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
+		ewma_init(&vi->rq[i].mrg_avg_pkt_len, 1, RECEIVE_AVG_WEIGHT);
+		sg_init_table(vi->sq[i].sg, ARRAY_SIZE(vi->sq[i].sg));
+	}
+
+	return 0;
+
+err_rq:
+	kfree(vi->sq);
+err_sq:
+	return -ENOMEM;
+}
+
+static int init_vqs(struct virtnet_info *vi)
+{
+	int ret;
+
+	/* Allocate send & receive queues */
+	ret = virtnet_alloc_queues(vi);
+	if (ret)
+		goto err;
+
+	ret = virtnet_find_vqs(vi);
+	if (ret)
+		goto err_free;
+
+	get_online_cpus();
+	virtnet_set_affinity(vi);
+	put_online_cpus();
+
+	return 0;
+
+err_free:
+	virtnet_free_queues(vi);
+err:
+	return ret;
+}
+
+#ifdef CONFIG_SYSFS
+static ssize_t mergeable_rx_buffer_size_show(struct netdev_rx_queue *queue,
+		struct rx_queue_attribute *attribute, char *buf)
+{
+	struct virtnet_info *vi = netdev_priv(queue->dev);
+	unsigned int queue_index = get_netdev_rx_queue_index(queue);
+	struct ewma *avg;
+
+	BUG_ON(queue_index >= vi->max_queue_pairs);
+	avg = &vi->rq[queue_index].mrg_avg_pkt_len;
+	return sprintf(buf, "%u\n", get_mergeable_buf_len(avg));
+}
+
+static struct rx_queue_attribute mergeable_rx_buffer_size_attribute =
+	__ATTR_RO(mergeable_rx_buffer_size);
+
+static struct attribute *virtio_net_mrg_rx_attrs[] = {
+	&mergeable_rx_buffer_size_attribute.attr,
+	NULL
+};
+
+static const struct attribute_group virtio_net_mrg_rx_group = {
+	.name = "virtio_net",
+	.attrs = virtio_net_mrg_rx_attrs
+};
+#endif
+
+static bool virtnet_fail_on_feature(struct virtio_device *vdev,
+				    unsigned int fbit,
+				    const char *fname, const char *dname)
+{
+	if (!virtio_has_feature(vdev, fbit))
+		return false;
+
+	dev_err(&vdev->dev, "device advertises feature %s but not %s",
+		fname, dname);
+
+	return true;
+}
+
+#define VIRTNET_FAIL_ON(vdev, fbit, dbit)			\
+	virtnet_fail_on_feature(vdev, fbit, #fbit, dbit)
+
+static bool virtnet_validate_features(struct virtio_device *vdev)
+{
+	if (!virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ) &&
+	    (VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_RX,
+			     "VIRTIO_NET_F_CTRL_VQ") ||
+	     VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_VLAN,
+			     "VIRTIO_NET_F_CTRL_VQ") ||
+	     VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_GUEST_ANNOUNCE,
+			     "VIRTIO_NET_F_CTRL_VQ") ||
+	     VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_MQ, "VIRTIO_NET_F_CTRL_VQ") ||
+	     VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR,
+			     "VIRTIO_NET_F_CTRL_VQ"))) {
+		return false;
+	}
+
+	return true;
+}
+
+static int virtnet_probe(struct virtio_device *vdev)
+{
+	int i, err;
+	struct net_device *dev;
+	struct virtnet_info *vi;
+	u16 max_queue_pairs;
+
+	if (!vdev->config->get) {
+		dev_err(&vdev->dev, "%s failure: config access disabled\n",
+			__func__);
+		return -EINVAL;
+	}
+
+	if (!virtnet_validate_features(vdev))
+		return -EINVAL;
+
+	/* Find if host supports multiqueue virtio_net device */
+	err = virtio_cread_feature(vdev, VIRTIO_NET_F_MQ,
+				   struct virtio_net_config,
+				   max_virtqueue_pairs, &max_queue_pairs);
+
+	/* We need at least 2 queue's */
+	if (err || max_queue_pairs < VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN ||
+	    max_queue_pairs > VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX ||
+	    !virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
+		max_queue_pairs = 1;
+
+	/* Allocate ourselves a network device with room for our info */
+	dev = alloc_etherdev_mq(sizeof(struct virtnet_info), max_queue_pairs);
+	if (!dev)
+		return -ENOMEM;
+
+	/* Set up network device as normal. */
+	dev->priv_flags |= IFF_UNICAST_FLT | IFF_LIVE_ADDR_CHANGE;
+	dev->netdev_ops = &virtnet_netdev;
+	dev->features = NETIF_F_HIGHDMA;
+
+	dev->ethtool_ops = &virtnet_ethtool_ops;
+	SET_NETDEV_DEV(dev, &vdev->dev);
+
+	/* Do we support "hardware" checksums? */
+	if (virtio_has_feature(vdev, VIRTIO_NET_F_CSUM)) {
+		/* This opens up the world of extra features. */
+		dev->hw_features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
+		if (csum)
+			dev->features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
+
+		if (virtio_has_feature(vdev, VIRTIO_NET_F_GSO)) {
+			dev->hw_features |= NETIF_F_TSO | NETIF_F_UFO
+				| NETIF_F_TSO_ECN | NETIF_F_TSO6;
+		}
+		/* Individual feature bits: what can host handle? */
+		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO4))
+			dev->hw_features |= NETIF_F_TSO;
+		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_TSO6))
+			dev->hw_features |= NETIF_F_TSO6;
+		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_ECN))
+			dev->hw_features |= NETIF_F_TSO_ECN;
+		if (virtio_has_feature(vdev, VIRTIO_NET_F_HOST_UFO))
+			dev->hw_features |= NETIF_F_UFO;
+
+		dev->features |= NETIF_F_GSO_ROBUST;
+
+		if (gso)
+			dev->features |= dev->hw_features & (NETIF_F_ALL_TSO|NETIF_F_UFO);
+		/* (!csum && gso) case will be fixed by register_netdev() */
+	}
+	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_CSUM))
+		dev->features |= NETIF_F_RXCSUM;
+
+	dev->vlan_features = dev->features;
+
+	/* Configuration may specify what MAC to use.  Otherwise random. */
+	if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
+		virtio_cread_bytes(vdev,
+				   offsetof(struct virtio_net_config, mac),
+				   dev->dev_addr, dev->addr_len);
+	else
+		eth_hw_addr_random(dev);
+
+	/* Set up our device-specific information */
+	vi = netdev_priv(dev);
+	vi->dev = dev;
+	vi->vdev = vdev;
+	vdev->priv = vi;
+	vi->stats = alloc_percpu(struct virtnet_stats);
+	err = -ENOMEM;
+	if (vi->stats == NULL)
+		goto free;
+
+	for_each_possible_cpu(i) {
+		struct virtnet_stats *virtnet_stats;
+		virtnet_stats = per_cpu_ptr(vi->stats, i);
+		u64_stats_init(&virtnet_stats->tx_syncp);
+		u64_stats_init(&virtnet_stats->rx_syncp);
+	}
+
+	INIT_WORK(&vi->config_work, virtnet_config_changed_work);
+
+	/* If we can receive ANY GSO packets, we must allocate large ones. */
+	if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
+	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) ||
+	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN) ||
+	    virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_UFO))
+		vi->big_packets = true;
+
+	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
+		vi->mergeable_rx_bufs = true;
+
+	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF) ||
+	    virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
+		vi->hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf);
+	else
+		vi->hdr_len = sizeof(struct virtio_net_hdr);
+
+	if (virtio_has_feature(vdev, VIRTIO_F_ANY_LAYOUT))
+		vi->any_header_sg = true;
+
+	if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
+		vi->has_cvq = true;
+
+	if (vi->any_header_sg)
+		dev->needed_headroom = vi->hdr_len;
+
+	/* Use single tx/rx queue pair as default */
+	vi->curr_queue_pairs = 1;
+	vi->max_queue_pairs = max_queue_pairs;
+
+	/* Allocate/initialize the rx/tx queues, and invoke find_vqs */
+	err = init_vqs(vi);
+	if (err)
+		goto free_stats;
+
+#ifdef CONFIG_SYSFS
+	if (vi->mergeable_rx_bufs)
+		dev->sysfs_rx_queue_group = &virtio_net_mrg_rx_group;
+#endif
+	netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs);
+	netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs);
+
+	err = register_netdev(dev);
+	if (err) {
+		pr_debug("virtio_net: registering device failed\n");
+		goto free_vqs;
+	}
+
+	virtio_device_ready(vdev);
+
+	/* Last of all, set up some receive buffers. */
+	for (i = 0; i < vi->curr_queue_pairs; i++) {
+		try_fill_recv(vi, &vi->rq[i], GFP_KERNEL);
+
+		/* If we didn't even get one input buffer, we're useless. */
+		if (vi->rq[i].vq->num_free ==
+		    virtqueue_get_vring_size(vi->rq[i].vq)) {
+			free_unused_bufs(vi);
+			err = -ENOMEM;
+			goto free_recv_bufs;
+		}
+	}
+
+	vi->nb.notifier_call = &virtnet_cpu_callback;
+	err = register_hotcpu_notifier(&vi->nb);
+	if (err) {
+		pr_debug("virtio_net: registering cpu notifier failed\n");
+		goto free_recv_bufs;
+	}
+
+	/* Assume link up if device can't report link status,
+	   otherwise get link status from config. */
+	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
+		netif_carrier_off(dev);
+		schedule_work(&vi->config_work);
+	} else {
+		vi->status = VIRTIO_NET_S_LINK_UP;
+		netif_carrier_on(dev);
+	}
+
+	pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
+		 dev->name, max_queue_pairs);
+
+	return 0;
+
+free_recv_bufs:
+	vi->vdev->config->reset(vdev);
+
+	free_receive_bufs(vi);
+	unregister_netdev(dev);
+free_vqs:
+	cancel_delayed_work_sync(&vi->refill);
+	free_receive_page_frags(vi);
+	virtnet_del_vqs(vi);
+free_stats:
+	free_percpu(vi->stats);
+free:
+	free_netdev(dev);
+	return err;
+}
+
+static void remove_vq_common(struct virtnet_info *vi)
+{
+	vi->vdev->config->reset(vi->vdev);
+
+	/* Free unused buffers in both send and recv, if any. */
+	free_unused_bufs(vi);
+
+	free_receive_bufs(vi);
+
+	free_receive_page_frags(vi);
+
+	virtnet_del_vqs(vi);
+}
+
+static void virtnet_remove(struct virtio_device *vdev)
+{
+	struct virtnet_info *vi = vdev->priv;
+
+	unregister_hotcpu_notifier(&vi->nb);
+
+	/* Make sure no work handler is accessing the device. */
+	flush_work(&vi->config_work);
+
+	unregister_netdev(vi->dev);
+
+	remove_vq_common(vi);
+
+	free_percpu(vi->stats);
+	free_netdev(vi->dev);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int virtnet_freeze(struct virtio_device *vdev)
+{
+	struct virtnet_info *vi = vdev->priv;
+	int i;
+
+	unregister_hotcpu_notifier(&vi->nb);
+
+	/* Make sure no work handler is accessing the device */
+	flush_work(&vi->config_work);
+
+	netif_device_detach(vi->dev);
+	cancel_delayed_work_sync(&vi->refill);
+
+	if (netif_running(vi->dev)) {
+		for (i = 0; i < vi->max_queue_pairs; i++)
+			napi_disable(&vi->rq[i].napi);
+	}
+
+	remove_vq_common(vi);
+
+	return 0;
+}
+
+static int virtnet_restore(struct virtio_device *vdev)
+{
+	struct virtnet_info *vi = vdev->priv;
+	int err, i;
+
+	err = init_vqs(vi);
+	if (err)
+		return err;
+
+	virtio_device_ready(vdev);
+
+	if (netif_running(vi->dev)) {
+		for (i = 0; i < vi->curr_queue_pairs; i++)
+			if (!try_fill_recv(vi, &vi->rq[i], GFP_KERNEL))
+				schedule_delayed_work(&vi->refill, 0);
+
+		for (i = 0; i < vi->max_queue_pairs; i++)
+			virtnet_napi_enable(&vi->rq[i]);
+	}
+
+	netif_device_attach(vi->dev);
+
+	rtnl_lock();
+	virtnet_set_queues(vi, vi->curr_queue_pairs);
+	rtnl_unlock();
+
+	err = register_hotcpu_notifier(&vi->nb);
+	if (err)
+		return err;
+
+	return 0;
+}
+#endif
+
+static struct virtio_device_id id_table[] = {
+	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
+	{ 0 },
+};
+
+static unsigned int features[] = {
+	VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GUEST_CSUM,
+	VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC,
+	VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6,
+	VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
+	VIRTIO_NET_F_GUEST_ECN, VIRTIO_NET_F_GUEST_UFO,
+	VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
+	VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
+	VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ,
+	VIRTIO_NET_F_CTRL_MAC_ADDR,
+	VIRTIO_F_ANY_LAYOUT,
+};
+
+static struct virtio_driver virtio_net_driver = {
+	.feature_table = features,
+	.feature_table_size = ARRAY_SIZE(features),
+	.driver.name =	KBUILD_MODNAME,
+	.driver.owner =	THIS_MODULE,
+	.id_table =	id_table,
+	.probe =	virtnet_probe,
+	.remove =	virtnet_remove,
+	.config_changed = virtnet_config_changed,
+#ifdef CONFIG_PM_SLEEP
+	.freeze =	virtnet_freeze,
+	.restore =	virtnet_restore,
+#endif
+};
+
+module_virtio_driver(virtio_net_driver);
+
+MODULE_DEVICE_TABLE(virtio, id_table);
+MODULE_DESCRIPTION("Virtio network driver");
+MODULE_LICENSE("GPL");