text: /*
   * Virtio Block Device
   *
   * Copyright IBM, Corp. 2007
   *
   * Authors:
   *  Anthony Liguori   <aliguori@us.ibm.com>
   *
   * This work is licensed under the terms of the GNU GPL, version 2.  See
   * the COPYING file in the top-level directory.
   *
   */
  
  #ifndef QEMU_VIRTIO_BLK_H
  #define QEMU_VIRTIO_BLK_H
  
  #include "standard-headers/linux/virtio_blk.h"
  #include "hw/virtio/virtio.h"
  #include "hw/block/block.h"
  #include "sysemu/iothread.h"
  #include "sysemu/block-backend.h"
  
  #define TYPE_VIRTIO_BLK "virtio-blk-device"
  #define VIRTIO_BLK(obj) \
          OBJECT_CHECK(VirtIOBlock, (obj), TYPE_VIRTIO_BLK)
  
  /* This is the last element of the write scatter-gather list */
  struct virtio_blk_inhdr
  {
      unsigned char status;
  };
  
  struct VirtIOBlkConf
  {
      BlockConf conf;
      IOThread *iothread;
      char *serial;
      uint32_t request_merging;
      uint16_t num_queues;
      uint16_t queue_size;
      uint32_t max_discard_sectors;
      uint32_t max_write_zeroes_sectors;
  };
  
  struct VirtIOBlockDataPlane;
  
  struct VirtIOBlockReq;
  typedef struct VirtIOBlock {
      VirtIODevice parent_obj;
      BlockBackend *blk;
      void *rq;
      QEMUBH *bh;
      VirtIOBlkConf conf;
      unsigned short sector_mask;
      bool original_wce;
      VMChangeStateEntry *change;
      bool dataplane_disabled;
      bool dataplane_started;
      struct VirtIOBlockDataPlane *dataplane;
      uint64_t host_features;
      size_t config_size;
  } VirtIOBlock;
  
  typedef struct VirtIOBlockReq {
      VirtQueueElement elem;
      int64_t sector_num;
      VirtIOBlock *dev;
      VirtQueue *vq;
      struct virtio_blk_inhdr *in;
      struct virtio_blk_outhdr out;
      QEMUIOVector qiov;
      size_t in_len;
      struct VirtIOBlockReq *next;
      struct VirtIOBlockReq *mr_next;
      BlockAcctCookie acct;
  } VirtIOBlockReq;
  
  #define VIRTIO_BLK_MAX_MERGE_REQS 32
  
  typedef struct MultiReqBuffer {
      VirtIOBlockReq *reqs[VIRTIO_BLK_MAX_MERGE_REQS];
      unsigned int num_reqs;
      bool is_write;
  } MultiReqBuffer;
  
  bool virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq);
  
  #endif
  