virtio-net: Incorporate a DeviceState pointer and let savevm track instances

Stuff a pointer to the DeviceState into the VirtIONet structure so that
we can easily remove the vmstate entry later.  Also, let vmstate track
the instance number (it should always be zero internally since the
device path should now be unique).
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

hw/virtio-net.c

@@ -60,6 +60,7 @@ typedef struct VirtIONet
         uint8_t *macs;
     } mac_table;
     uint32_t *vlans;
+    DeviceState *qdev;
 } VirtIONet;
 
 /* TODO
@@ -890,7 +891,6 @@ static void virtio_net_vmstate_change(void *opaque, int running, int reason)
 VirtIODevice *virtio_net_init(DeviceState *dev, NICConf *conf)
 {
     VirtIONet *n;
-    static int virtio_net_id;
 
     n = (VirtIONet *)virtio_common_init("virtio-net", VIRTIO_ID_NET,
                                         sizeof(struct virtio_net_config),
@@ -923,7 +923,8 @@ VirtIODevice *virtio_net_init(DeviceState *dev, NICConf *conf)
 
     n->vlans = qemu_mallocz(MAX_VLAN >> 3);
 
-    register_savevm(NULL, "virtio-net", virtio_net_id++, VIRTIO_NET_VM_VERSION,
+    n->qdev = dev;
+    register_savevm(dev, "virtio-net", -1, VIRTIO_NET_VM_VERSION,
                     virtio_net_save, virtio_net_load, n);
     n->vmstate = qemu_add_vm_change_state_handler(virtio_net_vmstate_change, n);
 
@@ -941,7 +942,7 @@ void virtio_net_exit(VirtIODevice *vdev)
 
     qemu_purge_queued_packets(&n->nic->nc);
 
-    unregister_savevm(NULL, "virtio-net", n);
+    unregister_savevm(n->qdev, "virtio-net", n);
 
     qemu_free(n->mac_table.macs);
     qemu_free(n->vlans);