vhost: Change the sequence of device start

This patch is part of adding vhost-user vhost_dev_start support. The
motivation is to improve backend configuration speed and reduce live
migration VM downtime.

Moving the device start routines after finishing all the necessary device
and VQ configuration, further aligning to the virtio specification for
"device initialization sequence".

Following patch will add vhost-user vhost_dev_start support.

Signed-off-by: Yajun Wu <yajunw@nvidia.com>
Acked-by: Parav Pandit <parav@nvidia.com>

Message-Id: <20221017064452.1226514-2-yajunw@nvidia.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Yajun Wu 2022-10-17 14:44:51 +08:00 committed by Michael S. Tsirkin
parent 1b2b12376c
commit 8b67fe0065
2 changed files with 16 additions and 13 deletions

View File

@ -168,13 +168,6 @@ static int vhost_user_blk_start(VirtIODevice *vdev, Error **errp)
goto err_guest_notifiers;
}
ret = vhost_dev_start(&s->dev, vdev);
if (ret < 0) {
error_setg_errno(errp, -ret, "Error starting vhost");
goto err_guest_notifiers;
}
s->started_vu = true;
/* guest_notifier_mask/pending not used yet, so just unmask
* everything here. virtio-pci will do the right thing by
* enabling/disabling irqfd.
@ -183,9 +176,20 @@ static int vhost_user_blk_start(VirtIODevice *vdev, Error **errp)
vhost_virtqueue_mask(&s->dev, vdev, i, false);
}
s->dev.vq_index_end = s->dev.nvqs;
ret = vhost_dev_start(&s->dev, vdev);
if (ret < 0) {
error_setg_errno(errp, -ret, "Error starting vhost");
goto err_guest_notifiers;
}
s->started_vu = true;
return ret;
err_guest_notifiers:
for (i = 0; i < s->dev.nvqs; i++) {
vhost_virtqueue_mask(&s->dev, vdev, i, true);
}
k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false);
err_host_notifiers:
vhost_dev_disable_notifiers(&s->dev, vdev);

View File

@ -389,21 +389,20 @@ int vhost_net_start(VirtIODevice *dev, NetClientState *ncs,
} else {
peer = qemu_get_peer(ncs, n->max_queue_pairs);
}
r = vhost_net_start_one(get_vhost_net(peer), dev);
if (r < 0) {
goto err_start;
}
if (peer->vring_enable) {
/* restore vring enable state */
r = vhost_set_vring_enable(peer, peer->vring_enable);
if (r < 0) {
vhost_net_stop_one(get_vhost_net(peer), dev);
goto err_start;
}
}
r = vhost_net_start_one(get_vhost_net(peer), dev);
if (r < 0) {
goto err_start;
}
}
return 0;