virtio_read_device_config
virtio_read_device_config(dev, 0, &blkcfg,
virtio_read_device_config(dev,
virtio_read_device_config(_dev, \
void virtio_read_device_config(device_t dev, bus_size_t offset,
virtio_read_device_config(dev, offset, &val, sizeof(type)); \