Commit a9f98bb5 authored by Jason Wang's avatar Jason Wang Committed by Anthony Liguori
Browse files

vhost: multiqueue support 



This patch lets vhost support multiqueue. The idea is simple, just launching
multiple threads of vhost and let each of vhost thread processing a subset of
the virtqueues of the device. After this change each emulated device can have
multiple vhost threads as its backend.

To do this, a virtqueue index were introduced to record to first virtqueue that
will be handled by this vhost_net device. Based on this and nvqs, vhost could
calculate its relative index to setup vhost_net device.

Since we may have many vhost/net devices for a virtio-net device. The setting of
guest notifiers were moved out of the starting/stopping of a specific vhost
thread. The vhost_net_{start|stop}() were renamed to
vhost_net_{start|stop}_one(), and a new vhost_net_{start|stop}() were introduced
to configure the guest notifiers and start/stop all vhost/vhost_net devices.

Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarAnthony Liguori <aliguori@us.ibm.com>
parent 264986e2

hw/vhost.c

+36 −46
Original line number Diff line number Diff line
@@ -616,14 +616,17 @@ static int vhost_virtqueue_start(struct vhost_dev *dev, 
{

    hwaddr s, l, a;

    int r;

    int vhost_vq_index = idx - dev->vq_index;

    struct vhost_vring_file file = {

        .index = idx,

        .index = vhost_vq_index

    };

    struct vhost_vring_state state = {

        .index = idx,

        .index = vhost_vq_index

    };

    struct VirtQueue *vvq = virtio_get_queue(vdev, idx);



    assert(idx >= dev->vq_index && idx < dev->vq_index + dev->nvqs);



    vq->num = state.num = virtio_queue_get_num(vdev, idx);

    r = ioctl(dev->control, VHOST_SET_VRING_NUM, &state);

    if (r) {
@@ -666,11 +669,12 @@ static int vhost_virtqueue_start(struct vhost_dev *dev, 
        goto fail_alloc_ring;

    }



    r = vhost_virtqueue_set_addr(dev, vq, idx, dev->log_enabled);

    r = vhost_virtqueue_set_addr(dev, vq, vhost_vq_index, dev->log_enabled);

    if (r < 0) {

        r = -errno;

        goto fail_alloc;

    }



    file.fd = event_notifier_get_fd(virtio_queue_get_host_notifier(vvq));

    r = ioctl(dev->control, VHOST_SET_VRING_KICK, &file);

    if (r) {
@@ -706,9 +710,10 @@ static void vhost_virtqueue_stop(struct vhost_dev *dev, 
                                    unsigned idx)

{

    struct vhost_vring_state state = {

        .index = idx,

        .index = idx - dev->vq_index

    };

    int r;

    assert(idx >= dev->vq_index && idx < dev->vq_index + dev->nvqs);

    r = ioctl(dev->control, VHOST_GET_VRING_BASE, &state);

    if (r < 0) {

        fprintf(stderr, "vhost VQ %d ring restore failed: %d\n", idx, r);
@@ -864,7 +869,9 @@ int vhost_dev_enable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev) 
    }



    for (i = 0; i < hdev->nvqs; ++i) {

        r = vdev->binding->set_host_notifier(vdev->binding_opaque, i, true);

        r = vdev->binding->set_host_notifier(vdev->binding_opaque,

                                             hdev->vq_index + i,

                                             true);

        if (r < 0) {

            fprintf(stderr, "vhost VQ %d notifier binding failed: %d\n", i, -r);

            goto fail_vq;
@@ -874,7 +881,9 @@ int vhost_dev_enable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev) 
    return 0;

fail_vq:

    while (--i >= 0) {

        r = vdev->binding->set_host_notifier(vdev->binding_opaque, i, false);

        r = vdev->binding->set_host_notifier(vdev->binding_opaque,

                                             hdev->vq_index + i,

                                             false);

        if (r < 0) {

            fprintf(stderr, "vhost VQ %d notifier cleanup error: %d\n", i, -r);

            fflush(stderr);
@@ -895,7 +904,9 @@ void vhost_dev_disable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev) 
    int i, r;



    for (i = 0; i < hdev->nvqs; ++i) {

        r = vdev->binding->set_host_notifier(vdev->binding_opaque, i, false);

        r = vdev->binding->set_host_notifier(vdev->binding_opaque,

                                             hdev->vq_index + i,

                                             false);

        if (r < 0) {

            fprintf(stderr, "vhost VQ %d notifier cleanup failed: %d\n", i, -r);

            fflush(stderr);
@@ -909,8 +920,9 @@ void vhost_dev_disable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev) 
 */

bool vhost_virtqueue_pending(struct vhost_dev *hdev, int n)

{

    struct vhost_virtqueue *vq = hdev->vqs + n;

    struct vhost_virtqueue *vq = hdev->vqs + n - hdev->vq_index;

    assert(hdev->started);

    assert(n >= hdev->vq_index && n < hdev->vq_index + hdev->nvqs);

    return event_notifier_test_and_clear(&vq->masked_notifier);

}
@@ -919,15 +931,16 @@ void vhost_virtqueue_mask(struct vhost_dev *hdev, VirtIODevice *vdev, int n, 
                         bool mask)

{

    struct VirtQueue *vvq = virtio_get_queue(vdev, n);

    int r;

    int r, index = n - hdev->vq_index;



    assert(hdev->started);

    assert(n >= hdev->vq_index && n < hdev->vq_index + hdev->nvqs);



    struct vhost_vring_file file = {

        .index = n,

        .index = index

    };

    if (mask) {

        file.fd = event_notifier_get_fd(&hdev->vqs[n].masked_notifier);

        file.fd = event_notifier_get_fd(&hdev->vqs[index].masked_notifier);

    } else {

        file.fd = event_notifier_get_fd(virtio_queue_get_guest_notifier(vvq));

    }
@@ -942,20 +955,6 @@ int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev) 


    hdev->started = true;



    if (!vdev->binding->set_guest_notifiers) {

        fprintf(stderr, "binding does not support guest notifiers\n");

        r = -ENOSYS;

        goto fail;

    }



    r = vdev->binding->set_guest_notifiers(vdev->binding_opaque,

                                           hdev->nvqs,

                                           true);

    if (r < 0) {

        fprintf(stderr, "Error binding guest notifier: %d\n", -r);

        goto fail_notifiers;

    }



    r = vhost_dev_set_features(hdev, hdev->log_enabled);

    if (r < 0) {

        goto fail_features;
@@ -969,7 +968,7 @@ int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev) 
        r = vhost_virtqueue_start(hdev,

                                  vdev,

                                  hdev->vqs + i,

                                 i);

                                  hdev->vq_index + i);

        if (r < 0) {

            goto fail_vq;

        }
@@ -994,13 +993,11 @@ fail_vq: 
        vhost_virtqueue_stop(hdev,

                             vdev,

                             hdev->vqs + i,

                                i);

                             hdev->vq_index + i);

    }

    i = hdev->nvqs;

fail_mem:

fail_features:

    vdev->binding->set_guest_notifiers(vdev->binding_opaque, hdev->nvqs, false);

fail_notifiers:

fail:



    hdev->started = false;

    return r;
@@ -1009,29 +1006,22 @@ fail: 
/* Host notifiers must be enabled at this point. */

void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev)

{

    int i, r;

    int i;



    for (i = 0; i < hdev->nvqs; ++i) {

        vhost_virtqueue_stop(hdev,

                             vdev,

                             hdev->vqs + i,

                                i);

                             hdev->vq_index + i);

    }

    for (i = 0; i < hdev->n_mem_sections; ++i) {

        vhost_sync_dirty_bitmap(hdev, &hdev->mem_sections[i],

                                0, (hwaddr)~0x0ull);

    }

    r = vdev->binding->set_guest_notifiers(vdev->binding_opaque,

                                           hdev->nvqs,

                                           false);

    if (r < 0) {

        fprintf(stderr, "vhost guest notifier cleanup failed: %d\n", r);

        fflush(stderr);

    }

    assert (r >= 0);



    hdev->started = false;

    g_free(hdev->log);

    hdev->log = NULL;

    hdev->log_size = 0;

}

hw/vhost.h

+2 −0
Original line number Diff line number Diff line
@@ -35,6 +35,8 @@ struct vhost_dev { 
    MemoryRegionSection *mem_sections;

    struct vhost_virtqueue *vqs;

    int nvqs;

    /* the first virtuque which would be used by this vhost dev */

    int vq_index;

    unsigned long long features;

    unsigned long long acked_features;

    unsigned long long backend_features;

hw/vhost_net.c

+78 −8
Original line number Diff line number Diff line
@@ -140,12 +140,21 @@ bool vhost_net_query(VHostNetState *net, VirtIODevice *dev) 
    return vhost_dev_query(&net->dev, dev);

}



int vhost_net_start(struct vhost_net *net,

                    VirtIODevice *dev)

static int vhost_net_start_one(struct vhost_net *net,

                               VirtIODevice *dev,

                               int vq_index)

{

    struct vhost_vring_file file = { };

    int r;



    if (net->dev.started) {

        return 0;

    }



    net->dev.nvqs = 2;

    net->dev.vqs = net->vqs;

    net->dev.vq_index = vq_index;



    r = vhost_dev_enable_notifiers(&net->dev, dev);

    if (r < 0) {

        goto fail_notifiers;
@@ -181,11 +190,15 @@ fail_notifiers: 
    return r;

}



void vhost_net_stop(struct vhost_net *net,

static void vhost_net_stop_one(struct vhost_net *net,

                               VirtIODevice *dev)

{

    struct vhost_vring_file file = { .fd = -1 };



    if (!net->dev.started) {

        return;

    }



    for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {

        int r = ioctl(net->dev.control, VHOST_NET_SET_BACKEND, &file);

        assert(r >= 0);
@@ -195,6 +208,61 @@ void vhost_net_stop(struct vhost_net *net, 
    vhost_dev_disable_notifiers(&net->dev, dev);

}



int vhost_net_start(VirtIODevice *dev, NetClientState *ncs,

                    int total_queues)

{

    int r, i = 0;



    if (!dev->binding->set_guest_notifiers) {

        error_report("binding does not support guest notifiers\n");

        r = -ENOSYS;

        goto err;

    }



    for (i = 0; i < total_queues; i++) {

        r = vhost_net_start_one(tap_get_vhost_net(ncs[i].peer), dev, i * 2);



        if (r < 0) {

            goto err;

        }

    }



    r = dev->binding->set_guest_notifiers(dev->binding_opaque,

                                          total_queues * 2,

                                          true);

    if (r < 0) {

        error_report("Error binding guest notifier: %d\n", -r);

        goto err;

    }



    return 0;



err:

    while (--i >= 0) {

        vhost_net_stop_one(tap_get_vhost_net(ncs[i].peer), dev);

    }

    return r;

}



void vhost_net_stop(VirtIODevice *dev, NetClientState *ncs,

                    int total_queues)

{

    int i, r;



    r = dev->binding->set_guest_notifiers(dev->binding_opaque,

                                          total_queues * 2,

                                          false);

    if (r < 0) {

        fprintf(stderr, "vhost guest notifier cleanup failed: %d\n", r);

        fflush(stderr);

    }

    assert(r >= 0);



    for (i = 0; i < total_queues; i++) {

        vhost_net_stop_one(tap_get_vhost_net(ncs[i].peer), dev);

    }

}



void vhost_net_cleanup(struct vhost_net *net)

{

    vhost_dev_cleanup(&net->dev);
@@ -224,13 +292,15 @@ bool vhost_net_query(VHostNetState *net, VirtIODevice *dev) 
    return false;

}



int vhost_net_start(struct vhost_net *net,

		    VirtIODevice *dev)

int vhost_net_start(VirtIODevice *dev,

                    NetClientState *ncs,

                    int total_queues)

{

    return -ENOSYS;

}

void vhost_net_stop(struct vhost_net *net,

		    VirtIODevice *dev)

void vhost_net_stop(VirtIODevice *dev,

                    NetClientState *ncs,

                    int total_queues)

{

}

hw/vhost_net.h

+2 −2
Original line number Diff line number Diff line
@@ -9,8 +9,8 @@ typedef struct vhost_net VHostNetState; 
VHostNetState *vhost_net_init(NetClientState *backend, int devfd, bool force);



bool vhost_net_query(VHostNetState *net, VirtIODevice *dev);

int vhost_net_start(VHostNetState *net, VirtIODevice *dev);

void vhost_net_stop(VHostNetState *net, VirtIODevice *dev);

int vhost_net_start(VirtIODevice *dev, NetClientState *ncs, int total_queues);

void vhost_net_stop(VirtIODevice *dev, NetClientState *ncs, int total_queues);



void vhost_net_cleanup(VHostNetState *net);

hw/virtio-net.c

+2 −2
Original line number Diff line number Diff line
@@ -130,14 +130,14 @@ static void virtio_net_vhost_status(VirtIONet *n, uint8_t status) 
            return;

        }

        n->vhost_started = 1;

        r = vhost_net_start(tap_get_vhost_net(nc->peer), &n->vdev);

        r = vhost_net_start(&n->vdev, nc, 1);

        if (r < 0) {

            error_report("unable to start vhost net: %d: "

                         "falling back on userspace virtio", -r);

            n->vhost_started = 0;

        }

    } else {

        vhost_net_stop(tap_get_vhost_net(nc->peer), &n->vdev);

        vhost_net_stop(&n->vdev, nc, 1);

        n->vhost_started = 0;

    }

}