Re: [net-next rfc v7 2/3] virtio_net: multiqueue support

Michael S. Tsirkin
2012-12-02T16:06:31Z

On Tue, Nov 27, 2012 at 06:15:59PM +0800, Jason Wang wrote:
> This addes multiqueue support to virtio_net driver. In multiple queue modes, the
> driver expects the number of queue paris is equal to the number of vcpus. To
> eliminate the contention bettwen vcpus and virtqueues, per-cpu virtqueue pairs
> were implemented through:
>
> - select the txq based on the smp processor id.
> - smp affinity hint were set to the vcpu that owns the queue pairs.
>
> Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
> drivers/net/virtio_net.c | 454 ++++++++++++++++++++++++++++++---------
> include/uapi/linux/virtio_net.h | 16 ++
> 2 files changed, 371 insertions(+), 99 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 7975133..bcaa6e5 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -84,17 +84,25 @@ struct virtnet_info {
> struct virtio_device *vdev;
> struct virtqueue *cvq;
> struct net_device *dev;
> - struct napi_struct napi;
> - 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;
>
> @@ -126,6 +134,34 @@ struct padded_vnet_hdr {
> char padding[6];
> };
>
> +static const struct ethtool_ops virtnet_ethtool_ops;
> +
> +/*
> + * Converting between virtqueue no. and kernel tx/rx queue no.
> + * 0:rx0 1:tx0 2:cvq 3:rx1 4:tx1 ... 2N+1:rxN 2N+2:txN
> + */

Weird, this isn't what spec v5 says: it says
0:rx0 1:tx0 2: rx1 3: tx1 .... vcq
We can change the spec to match but keeping all rx/tx
together seems a bit prettier?

> +static int vq2txq(struct virtqueue *vq)
> +{
> + int index = virtqueue_get_queue_index(vq);
> + return index == 1 ? 0 : (index - 2) / 2;
> +}
> +
> +static int txq2vq(int txq)
> +{
> + return txq ? 2 * txq + 2 : 1;
> +}
> +
> +static int vq2rxq(struct virtqueue *vq)
> +{
> + int index = virtqueue_get_queue_index(vq);
> + return index ? (index - 1) / 2 : 0;
> +}
> +
> +static int rxq2vq(int rxq)
> +{
> + return rxq ? 2 * rxq + 1 : 0;
> +}
> +
> static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb)
> {
> return (struct skb_vnet_hdr *)skb->cb;
> @@ -166,7 +202,7 @@ 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,
> @@ -503,7 +539,7 @@ 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)) {
> @@ -650,7 +686,8 @@ 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 +701,14 @@ 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 +723,12 @@ 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 +796,13 @@ 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->rq.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 +858,53 @@ static void virtnet_ack_link_announce(struct virtnet_info *vi)
> rtnl_unlock();
> }
>
> +static int virtnet_set_queues(struct virtnet_info *vi)
> +{
> + struct scatterlist sg;
> + struct virtio_net_ctrl_rfs s;
> + struct net_device *dev = vi->dev;
> +
> + s.virtqueue_pairs = vi->curr_queue_pairs;
> + sg_init_one(&sg, &s, sizeof(s));
> +
> + if (!vi->has_cvq)
> + return -EINVAL;
> +
> + if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RFS,
> + VIRTIO_NET_CTRL_RFS_VQ_PAIRS_SET, &sg, 1, 0)){
> + dev_warn(&dev->dev, "Fail to set the number of queue pairs to"
> + " %d\n", vi->curr_queue_pairs);
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +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->rq[i].refill, 0);
> + virtnet_napi_enable(&vi->rq[i]);
> + }
> +
> + 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->rq.refill);
> - napi_disable(&vi->rq.napi);
> + for (i = 0; i < vi->max_queue_pairs; i++) {
> + cancel_delayed_work_sync(&vi->rq[i].refill);
> + napi_disable(&vi->rq[i].napi);
> + }
>
> return 0;
> }
> @@ -948,8 +1016,8 @@ static void virtnet_get_ringparam(struct net_device *dev,
> {
> 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;
> }
> @@ -967,12 +1035,6 @@ static void virtnet_get_drvinfo(struct net_device *dev,
>
> }
>
> -static const struct ethtool_ops virtnet_ethtool_ops = {
> - .get_drvinfo = virtnet_get_drvinfo,
> - .get_link = ethtool_op_get_link,
> - .get_ringparam = virtnet_get_ringparam,
> -};
> -
> #define MIN_MTU 68
> #define MAX_MTU 65535
>
> @@ -984,6 +1046,20 @@ 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.
> + */
> +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 +1071,7 @@ 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 +1107,10 @@ 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);
> @@ -1046,41 +1123,212 @@ static void virtnet_config_changed(struct virtio_device *vdev)
> schedule_work(&vi->config_work);
> }
>
> -static int init_vqs(struct virtnet_info *vi)
> +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);
> + }
> +}
> +
> +/* Free memory allocated for send and receive queues */
> +static void virtnet_free_queues(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;
> + kfree(vi->rq);
> + vi->rq = NULL;
> + kfree(vi->sq);
> + vi->sq = NULL;
> +}
>
> - /* We expect two virtqueues, receive then send,
> - * and optionally control. */
> - nvqs = virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ? 3 : 2;
> +static void free_unused_bufs(struct virtnet_info *vi)
> +{
> + void *buf;
> + int i;
>
> - err = vi->vdev->config->find_vqs(vi->vdev, nvqs, vqs, callbacks, names);
> - if (err)
> - return err;
> + 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);
> + }
>
> - vi->rq.vq = vqs[0];
> - vi->sq.vq = vqs[1];
> + for (i = 0; i < vi->max_queue_pairs; i++) {
> + struct virtqueue *vq = vi->rq[i].vq;
>
> - if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) {
> - vi->cvq = vqs[2];
> + 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_set_affinity(struct virtnet_info *vi, bool set)
> +{
> + int i;
> +
> + 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);
> + }
> +}
> +
> +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 virtnet_find_vqs(struct virtnet_info *vi)
> +{
> + vq_callback_t **callbacks;
> + struct virtqueue **vqs;
> + int ret = -ENOMEM;
> + int i, total_vqs;
> + char **names;
> +
> + /*
> + * We expect 1 RX virtqueue followed by 1 TX virtqueue, followd by
> + * possible control virtqueue, followed by RX/TX N-1 queue pairs used
> + * in multiqueue mode.
> + */
> + 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);
> + callbacks = kzalloc(total_vqs * sizeof(*callbacks), GFP_KERNEL);
> + if (!vqs || !callbacks)
> + goto err_mem;
> + names = kzalloc(total_vqs * sizeof(*names), GFP_KERNEL);
> + if (!names)
> + goto err_mem;
> +
> + /* Parameters for control virtqueue, if any */
> + if (vi->has_cvq) {
> + callbacks[2] = NULL;
> + names[2] = kasprintf(GFP_KERNEL, "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;
> + names[rxq2vq(i)] = kasprintf(GFP_KERNEL, "input.%d", i);
> + names[txq2vq(i)] = kasprintf(GFP_KERNEL, "output.%d", i);
> + }
> +
> + ret = vi->vdev->config->find_vqs(vi->vdev, total_vqs, vqs, callbacks,
> + (const char **)names);
> + if (ret)
> + goto err_names;
> +
> + if (vi->has_cvq) {
> + vi->cvq = vqs[2];
> 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(callbacks);
> + kfree(vqs);
> +
> + return 0;
> +
> +err_names:
> + for (i = 0; i < total_vqs * 2; i ++)
> + kfree(names[i]);
> + kfree(names);
> +
> +err_mem:
> + kfree(callbacks);
> + kfree(vqs);
> +
> + return ret;
> +}
> +
> +static int virtnet_alloc_queues(struct virtnet_info *vi)
> +{
> + int i;
> +
> + vi->sq = kzalloc(sizeof(vi->sq[0]) * vi->max_queue_pairs, GFP_KERNEL);
> + vi->rq = kzalloc(sizeof(vi->rq[0]) * vi->max_queue_pairs, GFP_KERNEL);
> + if (!vi->rq || !vi->sq)
> + goto err;
> +
> + /* setup initial receive and send queue parameters */
> + for (i = 0; i < vi->max_queue_pairs; i++) {
> + vi->rq[i].pages = NULL;
> + INIT_DELAYED_WORK(&vi->rq[i].refill, refill_work);
> + 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:
> + virtnet_free_queues(vi);
> + 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 curr_queue_pairs;

Probably a good idea to rename this max_queue_pairs.

> +
> + /* Find if host supports multiqueue virtio_net device */
> + err = virtio_config_val(vdev, VIRTIO_NET_F_RFS,
> + offsetof(struct virtio_net_config,
> + max_virtqueue_pairs), &curr_queue_pairs);
> +
> + /* We need at least 2 queue's */
> + if (err)
> + curr_queue_pairs = 1;

Let's also validate against VIRTIO_NET_CTRL_RFS_VQ_PAIRS_MIN
and VIRTIO_NET_CTRL_RFS_VQ_PAIRS_MAX.

>
> /* 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), curr_queue_pairs);
> if (!dev)
> return -ENOMEM;
>
> @@ -1126,22 +1374,17 @@ 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->rq.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) ||
> @@ -1152,10 +1395,21 @@ 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 = curr_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");
> @@ -1163,12 +1417,15 @@ 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,
> @@ -1181,13 +1438,20 @@ 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, curr_queue_pairs);
> +
> return 0;
>
> -unregister:
> +free_recv_bufs:
> + free_receive_bufs(vi);
> unregister_netdev(dev);
> +
> free_vqs:
> - vdev->config->del_vqs(vdev);
> + for (i = 0; i <curr_queue_pairs; i++)
> + cancel_delayed_work_sync(&vi->rq[i].refill);
> + virtnet_del_vqs(vi);
> +
> free_stats:
> free_percpu(vi->stats);
> free:
> @@ -1195,28 +1459,6 @@ 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);
> @@ -1224,10 +1466,9 @@ static void remove_vq_common(struct virtnet_info *vi)
> /* Free unused buffers in both send and recv, if any. */
> free_unused_bufs(vi);
>
> - vi->vdev->config->del_vqs(vi->vdev);
> + free_receive_bufs(vi);
>
> - while (vi->rq.pages)
> - __free_pages(get_a_page(&vi->rq, GFP_KERNEL), 0);
> + virtnet_del_vqs(vi);
> }
>
> static void __devexit virtnet_remove(struct virtio_device *vdev)
> @@ -1253,6 +1494,7 @@ static void __devexit 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);
> @@ -1260,10 +1502,14 @@ static int virtnet_freeze(struct virtio_device *vdev)
> mutex_unlock(&vi->config_lock);
>
> netif_device_detach(vi->dev);
> - cancel_delayed_work_sync(&vi->rq.refill);
> + for (i = 0; i < vi->max_queue_pairs; i++)
> + cancel_delayed_work_sync(&vi->rq[i].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);
>
> @@ -1275,24 +1521,28 @@ 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->rq.refill, 0);
> + for (i = 0; i < vi->max_queue_pairs; i++)
> + if (!try_fill_recv(&vi->rq[i], GFP_KERNEL))
> + schedule_delayed_work(&vi->rq[i].refill, 0);
>
> mutex_lock(&vi->config_lock);
> vi->config_enable = true;
> mutex_unlock(&vi->config_lock);
>
> + BUG_ON(virtnet_set_queues(vi));
> +

Won't this always fail when control vq is off?

> return 0;
> }
> #endif
> @@ -1310,7 +1560,7 @@ 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_RFS,
> };
>
> static struct virtio_driver virtio_net_driver = {
> @@ -1328,6 +1578,12 @@ static struct virtio_driver virtio_net_driver = {
> #endif
> };
>
> +static const struct ethtool_ops virtnet_ethtool_ops = {
> + .get_drvinfo = virtnet_get_drvinfo,
> + .get_link = ethtool_op_get_link,
> + .get_ringparam = virtnet_get_ringparam,
> +};
> +
> static int __init init(void)
> {
> return register_virtio_driver(&virtio_net_driver);
> diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h
> index 2470f54..6056cec 100644
> --- a/include/uapi/linux/virtio_net.h
> +++ b/include/uapi/linux/virtio_net.h
> @@ -51,6 +51,7 @@
> #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_RFS 22 /* Device supports multiple TXQ/RXQ */
>
> #define VIRTIO_NET_S_LINK_UP 1 /* Link is up */
> #define VIRTIO_NET_S_ANNOUNCE 2 /* Announcement is needed */
> @@ -60,6 +61,8 @@ struct virtio_net_config {
> __u8 mac[6];
> /* See VIRTIO_NET_F_STATUS and VIRTIO_NET_S_* above */
> __u16 status;
> + /* Total number of RX/TX queues */
> + __u16 max_virtqueue_pairs;
> } __attribute__((packed));
>
> /* This is the first element of the scatter-gather list. If you don't
> @@ -166,4 +169,17 @@ struct virtio_net_ctrl_mac {
> #define VIRTIO_NET_CTRL_ANNOUNCE 3
> #define VIRTIO_NET_CTRL_ANNOUNCE_ACK 0
>
> +/*
> + * Control multiqueue
> + *
> + */
> +struct virtio_net_ctrl_rfs {
> + u16 virtqueue_pairs;
> +};
> +
> +#define VIRTIO_NET_CTRL_RFS 4
> + #define VIRTIO_NET_CTRL_RFS_VQ_PAIRS_SET 0
> + #define VIRTIO_NET_CTRL_RFS_VQ_PAIRS_MIN 1
> + #define VIRTIO_NET_CTRL_RFS_VQ_PAIRS_MAX 0x8000
> +
> #endif /* _LINUX_VIRTIO_NET_H */
> --
> 1.7.1