func: VirtIODevice *virtio_blk_init(DeviceState *dev, VirtIOBlkConf *blk)
  
  {
  
      VirtIOBlock *s;
  
      int cylinders, heads, secs;
  
      static int virtio_blk_id;
  
      DriveInfo *dinfo;
  
  
  
      if (!blk->conf.bs) {
  
          error_report("drive property not set");
  
          return NULL;
  
      }
  
      if (!bdrv_is_inserted(blk->conf.bs)) {
  
          error_report("Device needs media, but drive is empty");
  
          return NULL;
  
      }
  
  
  
      if (!blk->serial) {
  
          /* try to fall back to value set with legacy -drive serial=... */
  
          dinfo = drive_get_by_blockdev(blk->conf.bs);
  
          if (*dinfo->serial) {
  
              blk->serial = strdup(dinfo->serial);
  
          }
  
      }
  
  
  
      s = (VirtIOBlock *)virtio_common_init("virtio-blk", VIRTIO_ID_BLOCK,
  
                                            sizeof(struct virtio_blk_config),
  
                                            sizeof(VirtIOBlock));
  
  
  
      s->vdev.get_config = virtio_blk_update_config;
  
      s->vdev.get_features = virtio_blk_get_features;
  
      s->vdev.reset = virtio_blk_reset;
  
      s->bs = blk->conf.bs;
  
      s->conf = &blk->conf;
  
      s->blk = blk;
  
      s->rq = NULL;
  
      s->sector_mask = (s->conf->logical_block_size / BDRV_SECTOR_SIZE) - 1;
  
      bdrv_guess_geometry(s->bs, &cylinders, &heads, &secs);
  
  
  
      s->vq = virtio_add_queue(&s->vdev, 128, virtio_blk_handle_output);
  
  
  
      qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s);
  
      s->qdev = dev;
  
      register_savevm(dev, "virtio-blk", virtio_blk_id++, 2,
  
                      virtio_blk_save, virtio_blk_load, s);
  
      bdrv_set_dev_ops(s->bs, &virtio_block_ops, s);
  
      bdrv_set_buffer_alignment(s->bs, s->conf->logical_block_size);
  
  
  
      bdrv_iostatus_enable(s->bs);
  
      add_boot_device_path(s->conf->bootindex, dev, "/disk@0,0");
  
  
  
      return &s->vdev;
  
  }
  