Class Desc

src/device/virtio/virt_queue/split.hpp:80–91

   * @see virtio-v1.2#2.7.5 The Virtqueue Descriptor Table
   */
  struct [[gnu::packed]] Desc {
    /// Descriptor Table 对齐要求(字节)
    static constexpr size_t kAlign = 16;
    /// 缓冲区的客户机物理地址 (little-endian)
    uint64_t addr;
    /// 缓冲区长度(字节) (little-endian)
    uint32_t len;
    /// 标志位: DescFlags (little-endian)
    uint16_t flags;
    /// 下一个描述符的索引(当 flags & kDescFNext 时有效) (little-endian)
    uint16_t next;
  };

  /**
   * @brief Virtqueue Available Ring