2 files changed, 402 insertions, 98 deletions

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 02a71021565e..c0830488a390 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -58,6 +58,9 @@ struct send_queue {
 
         /* 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 */
@@ -75,22 +78,34 @@ struct receive_queue {
 
         /* 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;
+        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;
+
         /* enable config space updates */
         bool config_enable;
 
@@ -105,6 +120,9 @@ struct virtnet_info {
 
         /* Lock for config space updates */
         struct mutex config_lock;
+
+        /* Does the affinity hint is set for virtqueues? */
+        bool affinity_hint_set;
 };
 
 struct skb_vnet_hdr {
@@ -125,6 +143,29 @@ struct padded_vnet_hdr {
         char padding[6];
 };
 
+/* 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 (virtqueue_get_queue_index(vq) - 1) / 2;
+}
+
+static int txq2vq(int txq)
+{
+        return txq * 2 + 1;
+}
+
+static int vq2rxq(struct virtqueue *vq)
+{
+        return virtqueue_get_queue_index(vq) / 2;
+}
+
+static int rxq2vq(int rxq)
+{
+        return rxq * 2;
+}
+
 static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
 {
         return (struct skb_vnet_hdr *)skb->cb;
@@ -165,7 +206,7 @@ static void skb_xmit_done(struct virtqueue *vq)
         virtqueue_disable_cb(vq);
 
         /* We were probably waiting for more output buffers. */
-        netif_wake_queue(vi->dev);
+        netif_wake_subqueue(vi->dev, vq2txq(vq));
 }
 
 static void set_skb_frag(struct sk_buff *skb, struct page *page,
@@ -502,7 +543,7 @@ static bool try_fill_recv(struct receive_queue *rq, gfp_t gfp)
 static void skb_recv_done(struct virtqueue *rvq)
 {
         struct virtnet_info *vi = rvq->vdev->priv;
-        struct receive_queue *rq = &vi->rq;
+        struct receive_queue *rq = &vi->rq[vq2rxq(rvq)];
 
         /* Schedule NAPI, Suppress further interrupts if successful. */
         if (napi_schedule_prep(&rq->napi)) {
@@ -532,15 +573,21 @@ 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->max_queue_pairs; i++) {
+                struct receive_queue *rq = &vi->rq[i];
 
-        napi_disable(&vi->rq.napi);
-        still_empty = !try_fill_recv(&vi->rq, GFP_KERNEL);
-        virtnet_napi_enable(&vi->rq);
+                napi_disable(&rq->napi);
+                still_empty = !try_fill_recv(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);
+                /* 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_poll(struct napi_struct *napi, int budget)
@@ -578,6 +625,21 @@ again:
         return received;
 }
 
+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++) {
+                /* Make sure we have some buffers: if oom use wq. */
+                if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
+                        schedule_delayed_work(&vi->refill, 0);
+                virtnet_napi_enable(&vi->rq[i]);
+        }
+
+        return 0;
+}
+
 static unsigned int free_old_xmit_skbs(struct send_queue *sq)
 {
         struct sk_buff *skb;
@@ -650,7 +712,8 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
 static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
         struct virtnet_info *vi = netdev_priv(dev);
-        struct send_queue *sq = &vi->sq;
+        int qnum = skb_get_queue_mapping(skb);
+        struct send_queue *sq = &vi->sq[qnum];
         int capacity;
 
         /* Free up any pending old buffers before queueing new ones. */
@@ -664,13 +727,14 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
                 if (likely(capacity == -ENOMEM)) {
                         if (net_ratelimit())
                                 dev_warn(&dev->dev,
-                                         "TX queue failure: out of memory\n");
+                                         "TXQ (%d) failure: out of memory\n",
+                                         qnum);
                 } else {
                         dev->stats.tx_fifo_errors++;
                         if (net_ratelimit())
                                 dev_warn(&dev->dev,
-                                         "Unexpected TX queue failure: %d\n",
-                                         capacity);
+                                         "Unexpected TXQ (%d) failure: %d\n",
+                                         qnum, capacity);
                 }
                 dev->stats.tx_dropped++;
                 kfree_skb(skb);
@@ -685,12 +749,12 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
         /* Apparently nice girls don't return TX_BUSY; stop the queue
          * before it gets out of hand.  Naturally, this wastes entries. */
         if (capacity < 2+MAX_SKB_FRAGS) {
-                netif_stop_queue(dev);
+                netif_stop_subqueue(dev, qnum);
                 if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
                         /* More just got used, free them then recheck. */
                         capacity += free_old_xmit_skbs(sq);
                         if (capacity >= 2+MAX_SKB_FRAGS) {
-                                netif_start_queue(dev);
+                                netif_start_subqueue(dev, qnum);
                                 virtqueue_disable_cb(sq->vq);
                         }
                 }
@@ -758,23 +822,13 @@ static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev,
 static void virtnet_netpoll(struct net_device *dev)
 {
         struct virtnet_info *vi = netdev_priv(dev);
+        int i;
 
-        napi_schedule(&vi->rq.napi);
+        for (i = 0; i < vi->curr_queue_pairs; i++)
+                napi_schedule(&vi->rq[i].napi);
 }
 #endif
 
-static int virtnet_open(struct net_device *dev)
-{
-        struct virtnet_info *vi = netdev_priv(dev);
-
-        /* Make sure we have some buffers: if oom use wq. */
-        if (!try_fill_recv(&vi->rq, GFP_KERNEL))
-                schedule_delayed_work(&vi->refill, 0);
-
-        virtnet_napi_enable(&vi->rq);
-        return 0;
-}
-
 /*
  * Send command via the control virtqueue and check status.  Commands
  * supported by the hypervisor, as indicated by feature bits, should
@@ -830,13 +884,39 @@ static void virtnet_ack_link_announce(struct virtnet_info *vi)
         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 = 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, 1, 0)){
+                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;
+
+        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);
-        napi_disable(&vi->rq.napi);
+
+        for (i = 0; i < vi->max_queue_pairs; i++)
+                napi_disable(&vi->rq[i].napi);
 
         return 0;
 }
@@ -943,13 +1023,41 @@ static int virtnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid)
         return 0;
 }
 
+static void virtnet_set_affinity(struct virtnet_info *vi, bool set)
+{
+        int i;
+
+        /* 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()) && set) {
+                if (vi->affinity_hint_set)
+                        set = false;
+                else
+                        return;
+        }
+
+        for (i = 0; i < vi->max_queue_pairs; i++) {
+                int cpu = set ? i : -1;
+                virtqueue_set_affinity(vi->rq[i].vq, cpu);
+                virtqueue_set_affinity(vi->sq[i].vq, cpu);
+        }
+
+        if (set)
+                vi->affinity_hint_set = true;
+        else
+                vi->affinity_hint_set = false;
+}
+
 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.vq);
-        ring->tx_max_pending = virtqueue_get_vring_size(vi->sq.vq);
+        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;
 }
@@ -984,6 +1092,21 @@ static int virtnet_change_mtu(struct net_device *dev, int new_mtu)
         return 0;
 }
 
+/* To avoid contending a lock hold by a vcpu who would exit to host, select the
+ * txq based on the processor id.
+ * TODO: handle cpu hotplug.
+ */
+static u16 virtnet_select_queue(struct net_device *dev, struct sk_buff *skb)
+{
+        int txq = skb_rx_queue_recorded(skb) ? skb_get_rx_queue(skb) :
+                  smp_processor_id();
+
+        while (unlikely(txq >= dev->real_num_tx_queues))
+                txq -= dev->real_num_tx_queues;
+
+        return txq;
+}
+
 static const struct net_device_ops virtnet_netdev = {
         .ndo_open            = virtnet_open,
         .ndo_stop            = virtnet_close,
@@ -995,6 +1118,7 @@ static const struct net_device_ops virtnet_netdev = {
         .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,
+        .ndo_select_queue     = virtnet_select_queue,
 #ifdef CONFIG_NET_POLL_CONTROLLER
         .ndo_poll_controller = virtnet_netpoll,
 #endif
@@ -1030,10 +1154,10 @@ static void virtnet_config_changed_work(struct work_struct *work)
 
         if (vi->status & VIRTIO_NET_S_LINK_UP) {
                 netif_carrier_on(vi->dev);
-                netif_wake_queue(vi->dev);
+                netif_tx_wake_all_queues(vi->dev);
         } else {
                 netif_carrier_off(vi->dev);
-                netif_stop_queue(vi->dev);
+                netif_tx_stop_all_queues(vi->dev);
         }
 done:
         mutex_unlock(&vi->config_lock);
@@ -1046,48 +1170,203 @@ static void virtnet_config_changed(struct virtio_device *vdev)
         schedule_work(&vi->config_work);
 }
 
+static void virtnet_free_queues(struct virtnet_info *vi)
+{
+        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_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 || vi->big_packets)
+                                give_pages(&vi->rq[i], buf);
+                        else
+                                dev_kfree_skb(buf);
+                        --vi->rq[i].num;
+                }
+                BUG_ON(vi->rq[i].num != 0);
+        }
+}
+
 static void virtnet_del_vqs(struct virtnet_info *vi)
 {
         struct virtio_device *vdev = vi->vdev;
 
+        virtnet_set_affinity(vi, false);
+
         vdev->config->del_vqs(vdev);
+
+        virtnet_free_queues(vi);
 }
 
-static int init_vqs(struct virtnet_info *vi)
+static int virtnet_find_vqs(struct virtnet_info *vi)
 {
-        struct virtqueue *vqs[3];
-        vq_callback_t *callbacks[] = { skb_recv_done, skb_xmit_done, NULL};
-        const char *names[] = { "input", "output", "control" };
-        int nvqs, err;
-
-        /* We expect two virtqueues, receive then send,
-         * and optionally control. */
-        nvqs = virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ? 3 : 2;
-
-        err = vi->vdev->config->find_vqs(vi->vdev, nvqs, vqs, callbacks, names);
-        if (err)
-                return err;
+        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";
+        }
 
-        vi->rq.vq = vqs[0];
-        vi->sq.vq = vqs[1];
+        /* 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;
+        }
 
-        if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) {
-                vi->cvq = vqs[2];
+        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_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->sq)
+                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);
+
+                sg_init_table(vi->rq[i].sg, ARRAY_SIZE(vi->rq[i].sg));
+                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;
+
+        virtnet_set_affinity(vi, true);
+        return 0;
+
+err_free:
+        virtnet_free_queues(vi);
+err:
+        return ret;
 }
 
 static int virtnet_probe(struct virtio_device *vdev)
 {
-        int err;
+        int i, err;
         struct net_device *dev;
         struct virtnet_info *vi;
+        u16 max_queue_pairs;
+
+        /* Find if host supports multiqueue virtio_net device */
+        err = virtio_config_val(vdev, VIRTIO_NET_F_MQ,
+                                offsetof(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(sizeof(struct virtnet_info));
+        dev = alloc_etherdev_mq(sizeof(struct virtnet_info), max_queue_pairs);
         if (!dev)
                 return -ENOMEM;
 
@@ -1133,22 +1412,17 @@ static int virtnet_probe(struct virtio_device *vdev)
 
         /* Set up our device-specific information */
         vi = netdev_priv(dev);
-        netif_napi_add(dev, &vi->rq.napi, virtnet_poll, napi_weight);
         vi->dev = dev;
         vi->vdev = vdev;
         vdev->priv = vi;
-        vi->rq.pages = NULL;
         vi->stats = alloc_percpu(struct virtnet_stats);
         err = -ENOMEM;
         if (vi->stats == NULL)
                 goto free;
 
-        INIT_DELAYED_WORK(&vi->refill, refill_work);
         mutex_init(&vi->config_lock);
         vi->config_enable = true;
         INIT_WORK(&vi->config_work, virtnet_config_changed_work);
-        sg_init_table(vi->rq.sg, ARRAY_SIZE(vi->rq.sg));
-        sg_init_table(vi->sq.sg, ARRAY_SIZE(vi->sq.sg));
 
         /* If we can receive ANY GSO packets, we must allocate large ones. */
         if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) ||
@@ -1159,10 +1433,21 @@ static int virtnet_probe(struct virtio_device *vdev)
         if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
                 vi->mergeable_rx_bufs = true;
 
+        if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ))
+                vi->has_cvq = true;
+
+        /* 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;
 
+        netif_set_real_num_tx_queues(dev, 1);
+        netif_set_real_num_rx_queues(dev, 1);
+
         err = register_netdev(dev);
         if (err) {
                 pr_debug("virtio_net: registering device failed\n");
@@ -1170,12 +1455,15 @@ static int virtnet_probe(struct virtio_device *vdev)
         }
 
         /* Last of all, set up some receive buffers. */
-        try_fill_recv(&vi->rq, GFP_KERNEL);
-
-        /* If we didn't even get one input buffer, we're useless. */
-        if (vi->rq.num == 0) {
-                err = -ENOMEM;
-                goto unregister;
+        for (i = 0; i < vi->max_queue_pairs; i++) {
+                try_fill_recv(&vi->rq[i], GFP_KERNEL);
+
+                /* If we didn't even get one input buffer, we're useless. */
+                if (vi->rq[i].num == 0) {
+                        free_unused_bufs(vi);
+                        err = -ENOMEM;
+                        goto free_recv_bufs;
+                }
         }
 
         /* Assume link up if device can't report link status,
@@ -1188,12 +1476,16 @@ static int virtnet_probe(struct virtio_device *vdev)
                 netif_carrier_on(dev);
         }
 
-        pr_debug("virtnet: registered device %s\n", dev->name);
+        pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
+                 dev->name, max_queue_pairs);
+
         return 0;
 
-unregister:
+free_recv_bufs:
+        free_receive_bufs(vi);
         unregister_netdev(dev);
 free_vqs:
+        cancel_delayed_work_sync(&vi->refill);
         virtnet_del_vqs(vi);
 free_stats:
         free_percpu(vi->stats);
@@ -1202,28 +1494,6 @@ free:
         return err;
 }
 
-static void free_unused_bufs(struct virtnet_info *vi)
-{
-        void *buf;
-        while (1) {
-                buf = virtqueue_detach_unused_buf(vi->sq.vq);
-                if (!buf)
-                        break;
-                dev_kfree_skb(buf);
-        }
-        while (1) {
-                buf = virtqueue_detach_unused_buf(vi->rq.vq);
-                if (!buf)
-                        break;
-                if (vi->mergeable_rx_bufs || vi->big_packets)
-                        give_pages(&vi->rq, buf);
-                else
-                        dev_kfree_skb(buf);
-                --vi->rq.num;
-        }
-        BUG_ON(vi->rq.num != 0);
-}
-
 static void remove_vq_common(struct virtnet_info *vi)
 {
         vi->vdev->config->reset(vi->vdev);
@@ -1231,10 +1501,9 @@ static void remove_vq_common(struct virtnet_info *vi)
         /* Free unused buffers in both send and recv, if any. */
         free_unused_bufs(vi);
 
-        virtnet_del_vqs(vi);
+        free_receive_bufs(vi);
 
-        while (vi->rq.pages)
-                __free_pages(get_a_page(&vi->rq, GFP_KERNEL), 0);
+        virtnet_del_vqs(vi);
 }
 
 static void virtnet_remove(struct virtio_device *vdev)
@@ -1260,6 +1529,7 @@ static void virtnet_remove(struct virtio_device *vdev)
 static int virtnet_freeze(struct virtio_device *vdev)
 {
         struct virtnet_info *vi = vdev->priv;
+        int i;
 
         /* Prevent config work handler from accessing the device */
         mutex_lock(&vi->config_lock);
@@ -1270,7 +1540,10 @@ static int virtnet_freeze(struct virtio_device *vdev)
         cancel_delayed_work_sync(&vi->refill);
 
         if (netif_running(vi->dev))
-                napi_disable(&vi->rq.napi);
+                for (i = 0; i < vi->max_queue_pairs; i++) {
+                        napi_disable(&vi->rq[i].napi);
+                        netif_napi_del(&vi->rq[i].napi);
+                }
 
         remove_vq_common(vi);
 
@@ -1282,24 +1555,28 @@ static int virtnet_freeze(struct virtio_device *vdev)
 static int virtnet_restore(struct virtio_device *vdev)
 {
         struct virtnet_info *vi = vdev->priv;
-        int err;
+        int err, i;
 
         err = init_vqs(vi);
         if (err)
                 return err;
 
         if (netif_running(vi->dev))
-                virtnet_napi_enable(&vi->rq);
+                for (i = 0; i < vi->max_queue_pairs; i++)
+                        virtnet_napi_enable(&vi->rq[i]);
 
         netif_device_attach(vi->dev);
 
-        if (!try_fill_recv(&vi->rq, GFP_KERNEL))
-                schedule_delayed_work(&vi->refill, 0);
+        for (i = 0; i < vi->max_queue_pairs; i++)
+                if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
+                        schedule_delayed_work(&vi->refill, 0);
 
         mutex_lock(&vi->config_lock);
         vi->config_enable = true;
         mutex_unlock(&vi->config_lock);
 
+        virtnet_set_queues(vi, vi->curr_queue_pairs);
+
         return 0;
 }
 #endif
@@ -1317,7 +1594,7 @@ static unsigned int features[] = {
         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_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ,
 };
 
 static struct virtio_driver virtio_net_driver = {
diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h
index 2470f541af50..848e3584d7c8 100644
--- a/include/uapi/linux/virtio_net.h
+++ b/include/uapi/linux/virtio_net.h
@@ -51,6 +51,8 @@
 #define VIRTIO_NET_F_CTRL_RX_EXTRA 20   /* Extra RX mode control support */
 #define VIRTIO_NET_F_GUEST_ANNOUNCE 21  /* Guest can announce device on the
                                          * network */
+#define VIRTIO_NET_F_MQ 22      /* Device supports Receive Flow
+                                         * Steering */
 
 #define VIRTIO_NET_S_LINK_UP    1       /* Link is up */
 #define VIRTIO_NET_S_ANNOUNCE   2       /* Announcement is needed */
@@ -60,6 +62,11 @@ struct virtio_net_config {
         __u8 mac[6];
         /* See VIRTIO_NET_F_STATUS and VIRTIO_NET_S_* above */
         __u16 status;
+        /* Maximum number of each of transmit and receive queues;
+         * see VIRTIO_NET_F_MQ and VIRTIO_NET_CTRL_MQ.
+         * Legal values are between 1 and 0x8000
+         */
+        __u16 max_virtqueue_pairs;
 } __attribute__((packed));
 
 /* This is the first element of the scatter-gather list.  If you don't
@@ -166,4 +173,24 @@ struct virtio_net_ctrl_mac {
 #define VIRTIO_NET_CTRL_ANNOUNCE       3
  #define VIRTIO_NET_CTRL_ANNOUNCE_ACK         0
 
+/*
+ * Control Receive Flow Steering
+ *
+ * The command VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET
+ * enables Receive Flow Steering, specifying the number of the transmit and
+ * receive queues that will be used. After the command is consumed and acked by
+ * the device, the device will not steer new packets on receive virtqueues
+ * other than specified nor read from transmit virtqueues other than specified.
+ * Accordingly, driver should not transmit new packets  on virtqueues other than
+ * specified.
+ */
+struct virtio_net_ctrl_mq {
+        u16 virtqueue_pairs;
+};
+
+#define VIRTIO_NET_CTRL_MQ   4
+ #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET        0
+ #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN        1
+ #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX        0x8000
+
 #endif /* _LINUX_VIRTIO_NET_H */