This connects virtio-net to vhost net backend.

The code is structured in a way analogous to what we have with vnet

header capability in tap.  We start/stop backend on driver start/stop as

well as on save and vm start (for migration).

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

---

 hw/virtio-net.c |   67 +++++++++++++++++++++++++++++++++++++++++++++++++++++-

 1 files changed, 65 insertions(+), 2 deletions(-)

diff --git a/hw/virtio-net.c b/hw/virtio-net.c

index 02d9180..088029b 100644

--- a/hw/virtio-net.c

+++ b/hw/virtio-net.c

@@ -17,6 +17,7 @@

 #include "net/tap.h"

 #include "qemu-timer.h"

 #include "virtio-net.h"

+#include "vhost_net.h"

 #define VIRTIO_NET_VM_VERSION    11

@@ -47,6 +48,8 @@ typedef struct VirtIONet

     uint8_t nomulti;

     uint8_t nouni;

     uint8_t nobcast;

+    uint8_t vhost_started;

+    VMChangeStateEntry *vmstate;

     struct {

         int in_use;

         int first_multi;

@@ -114,6 +117,10 @@ static void virtio_net_reset(VirtIODevice *vdev)

     n->nomulti = 0;

     n->nouni = 0;

     n->nobcast = 0;

+    if (n->vhost_started) {

+        vhost_net_stop(tap_get_vhost_net(n->nic->nc.peer), vdev);

+        n->vhost_started = 0;

+    }

     /* Flush any MAC and VLAN filter table state */

     n->mac_table.in_use = 0;

@@ -172,7 +179,10 @@ static uint32_t virtio_net_get_features(VirtIODevice *vdev, uint32_t features)

         features &= ~(0x1 << VIRTIO_NET_F_HOST_UFO);

     }

-    return features;

+    if (!tap_get_vhost_net(n->nic->nc.peer)) {

+        return features;

+    }

+    return vhost_net_get_features(tap_get_vhost_net(n->nic->nc.peer), features);

 }

 static uint32_t virtio_net_bad_features(VirtIODevice *vdev)

@@ -690,6 +700,12 @@ static void virtio_net_save(QEMUFile *f, void *opaque)

 {

     VirtIONet *n = opaque;

+    if (n->vhost_started) {

+	/* TODO: should we really stop the backend?

+	 * If we don't, it might keep writing to memory. */

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

+	n->vhost_started = 0;

+    }

     virtio_save(&n->vdev, f);

     qemu_put_buffer(f, n->mac, ETH_ALEN);

@@ -802,7 +818,6 @@ static int virtio_net_load(QEMUFile *f, void *opaque, int version_id)

         qemu_mod_timer(n->tx_timer,

                        qemu_get_clock(vm_clock) + TX_TIMER_INTERVAL);

     }

-

     return 0;

 }

@@ -822,6 +837,47 @@ static NetClientInfo net_virtio_info = {

     .link_status_changed = virtio_net_set_link_status,

 };

+static void virtio_net_set_status(struct VirtIODevice *vdev)

+{

+    VirtIONet *n = to_virtio_net(vdev);

+    if (!n->nic->nc.peer) {

+        return;

+    }

+    if (n->nic->nc.peer->info->type != NET_CLIENT_TYPE_TAP) {

+        return;

+    }

+

+    if (!tap_get_vhost_net(n->nic->nc.peer)) {

+        return;

+    }

+    if (!!n->vhost_started == !!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) {

+        return;

+    }

+    if (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) {

+        int r = vhost_net_start(tap_get_vhost_net(n->nic->nc.peer), vdev);

+        if (r < 0) {

+            fprintf(stderr, "unable to start vhost net: %d: "

+                    "falling back on userspace virtio\n", -r);

+        } else {

+            n->vhost_started = 1;

+        }

+    } else {

+        vhost_net_stop(tap_get_vhost_net(n->nic->nc.peer), vdev);

+        n->vhost_started = 0;

+    }

+}

+

+static void virtio_net_vmstate_change(void *opaque, int running, int reason)

+{

+	VirtIONet *n = opaque;

+	if (!running) {

+		return;

+	}

+	/* This is called when vm is started, it will start vhost backend if it

+	 * appropriate e.g. after migration. */

+	virtio_net_set_status(&n->vdev);

+}

+

 VirtIODevice *virtio_net_init(DeviceState *dev, NICConf *conf)

 {

     VirtIONet *n;

@@ -837,6 +893,7 @@ VirtIODevice *virtio_net_init(DeviceState *dev, NICConf *conf)

     n->vdev.set_features = virtio_net_set_features;

     n->vdev.bad_features = virtio_net_bad_features;

     n->vdev.reset = virtio_net_reset;

+    n->vdev.set_status = virtio_net_set_status;

     n->rx_vq = virtio_add_queue(&n->vdev, 256, virtio_net_handle_rx);

     n->tx_vq = virtio_add_queue(&n->vdev, 256, virtio_net_handle_tx);

     n->ctrl_vq = virtio_add_queue(&n->vdev, 64, virtio_net_handle_ctrl);

@@ -859,6 +916,7 @@ VirtIODevice *virtio_net_init(DeviceState *dev, NICConf *conf)

     register_savevm("virtio-net", virtio_net_id++, VIRTIO_NET_VM_VERSION,

                     virtio_net_save, virtio_net_load, n);

+    n->vmstate = qemu_add_vm_change_state_handler(virtio_net_vmstate_change, n);

     return &n->vdev;

 }

@@ -866,6 +924,11 @@ VirtIODevice *virtio_net_init(DeviceState *dev, NICConf *conf)

 void virtio_net_exit(VirtIODevice *vdev)

 {

     VirtIONet *n = DO_UPCAST(VirtIONet, vdev, vdev);

+    qemu_del_vm_change_state_handler(n->vmstate);

+

+    if (n->vhost_started) {

+        vhost_net_stop(tap_get_vhost_net(n->nic->nc.peer), vdev);

+    }

     qemu_purge_queued_packets(&n->nic->nc);

-- 

1.6.6.144.g5c3af