static void virtio_scsi_push_event(VirtIOSCSI *s, SCSIDevice *dev,

                                   uint32_t event, uint32_t reason)

{

    VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);

    VirtIOSCSIReq *req = virtio_scsi_pop_req(s, vs->event_vq);

    VirtIOSCSIEvent *evt;

    VirtIODevice *vdev = VIRTIO_DEVICE(s);

    int in_size;



    if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) {

        return;

    }



    if (!req) {

        s->events_dropped = true;

        return;

    }



    if (req->elem.out_num || req->elem.in_num != 1) {

        virtio_scsi_bad_req();

    }



    if (s->events_dropped) {

        event |= VIRTIO_SCSI_T_EVENTS_MISSED;

        s->events_dropped = false;

    }



    in_size = req->elem.in_sg[0].iov_len;

    if (in_size < sizeof(VirtIOSCSIEvent)) {

        virtio_scsi_bad_req();

    }



    evt = req->resp.event;

    memset(evt, 0, sizeof(VirtIOSCSIEvent));

    evt->event = event;

    evt->reason = reason;

    if (!dev) {

        assert(event == VIRTIO_SCSI_T_NO_EVENT);

    } else {

        evt->lun[0] = 1;

        evt->lun[1] = dev->id;



        /* Linux wants us to keep the same encoding we use for REPORT LUNS.  */

        if (dev->lun >= 256) {

            evt->lun[2] = (dev->lun >> 8) | 0x40;

        }

        evt->lun[3] = dev->lun & 0xFF;

    }

    virtio_scsi_complete_req(req);

}
