On 01/25/2013 06:35 PM, Jason Wang wrote:
> 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: Jason Wang <jasowang@xxxxxxxxxx>
> ---
> hw/vhost.c | 82 +++++++++++++++++++++---------------------------
> hw/vhost.h | 2 +
> hw/vhost_net.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++-----
> hw/vhost_net.h | 6 ++-
> hw/virtio-net.c | 4 +-
> 5 files changed, 128 insertions(+), 58 deletions(-)
>
> diff --git a/hw/vhost.c b/hw/vhost.c
> index cee8aad..38257b9 100644
> --- a/hw/vhost.c
> +++ b/hw/vhost.c
> @@ -619,14 +619,17 @@ 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) {
> @@ -669,11 +672,12 @@ 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) {
> @@ -709,9 +713,10 @@ 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);
> @@ -867,7 +872,9 @@ 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;
> @@ -877,7 +884,9 @@ 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);
> @@ -898,7 +907,9 @@ 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);
> @@ -912,8 +923,9 @@ 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);
> }
>
> @@ -922,15 +934,16 @@ 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));
> }
> @@ -945,20 +958,6 @@ 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;
> @@ -970,9 +969,9 @@ int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
> }
> for (i = 0; i < hdev->nvqs; ++i) {
> r = vhost_virtqueue_start(hdev,
> - vdev,
> - hdev->vqs + i,
> - i);
> + vdev,
> + hdev->vqs + i,
> + hdev->vq_index + i);
> if (r < 0) {
> goto fail_vq;
> }
> @@ -995,15 +994,13 @@ fail_log:
> fail_vq:
> while (--i >= 0) {
> vhost_virtqueue_stop(hdev,
> - vdev,
> - hdev->vqs + i,
> - i);
> + vdev,
> + hdev->vqs + 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;
> @@ -1012,29 +1009,22 @@ 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);
> + vdev,
> + hdev->vqs + 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;
> }
> +
> diff --git a/hw/vhost.h b/hw/vhost.h
> index 44c61a5..f062d48 100644
> --- a/hw/vhost.h
> +++ b/hw/vhost.h
> @@ -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;
> diff --git a/hw/vhost_net.c b/hw/vhost_net.c
> index d3a04ca..c955611 100644
> --- a/hw/vhost_net.c
> +++ b/hw/vhost_net.c
> @@ -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,
> - VirtIODevice *dev)
> +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 +208,65 @@ void vhost_net_stop(struct vhost_net *net,
> vhost_dev_disable_notifiers(&net->dev, dev);
> }
>
> +int vhost_net_start(VirtIODevice *dev, NetClientState *ncs,
> + int start_queues, 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 = start_queues; i < total_queues; i++) {
> + vhost_net_stop_one(tap_get_vhost_net(ncs[i].peer), dev);
> + }
> +
Since kernel will support polling/writing when detached, there's no need
to stop the vhost threads that is polling the disabled queue here. This
can further simplify the interface between virtio-net and vhost.
Will send a new version.
> + for (i = 0; i < start_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,
> + start_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 start_queues, int total_queues)
> +{
> + int i, r;
> +
> + r = dev->binding->set_guest_notifiers(dev->binding_opaque,
> + start_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 +296,17 @@ 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 start_queues,
> + int total_queues)
> {
> return -ENOSYS;
> }
> -void vhost_net_stop(struct vhost_net *net,
> - VirtIODevice *dev)
> +void vhost_net_stop(VirtIODevice *dev,
> + NetClientState *ncs,
> + int start_queues,
> + int total_queues)
> {
> }
>
> diff --git a/hw/vhost_net.h b/hw/vhost_net.h
> index 88912b8..9fbd79d 100644
> --- a/hw/vhost_net.h
> +++ b/hw/vhost_net.h
> @@ -9,8 +9,10 @@ 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 start_queues, int total_queues);
> +void vhost_net_stop(VirtIODevice *dev, NetClientState *ncs,
> + int start_queues, int total_queues);
>
> void vhost_net_cleanup(VHostNetState *net);
>
> diff --git a/hw/virtio-net.c b/hw/virtio-net.c
> index 47f4ab4..2f49fd8 100644
> --- a/hw/virtio-net.c
> +++ b/hw/virtio-net.c
> @@ -129,14 +129,14 @@ 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, 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, 1);
> n->vhost_started = 0;
> }
> }
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
