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: Jason Wang <jasowang@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/hw/virtio-net.c b/hw/virtio-net.c
index a967006cfc..f4146aafc8 100644
--- a/hw/virtio-net.c
+++ b/hw/virtio-net.c
@@ -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;
     }
 }