text: /* 
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to
   * deal in the Software without restriction, including without limitation the
   * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
   * sell copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
   * DEALINGS IN THE SOFTWARE.
   */
  #ifndef __XEN_BLKIF_H__
  #define __XEN_BLKIF_H__
  
  #include <public/io/ring.h>
  #include <public/io/blkif.h>
  #include <public/io/protocols.h>
  
  /* Not a real protocol.  Used to generate ring structs which contain
   * the elements common to all protocols only.  This way we get a
   * compiler-checkable way to use common struct elements, so we can
   * avoid using switch(protocol) in a number of places.  */
  
  /* i386 protocol version */
  
  #pragma pack(4)
  
  struct blkif_x86_32_request {
  	uint8_t        operation;    /* BLKIF_OP_???                         */
  	uint8_t        nr_segments;  /* number of segments                   */
  	blkif_vdev_t   handle;       /* only for read/write requests         */
  	uint64_t       id;           /* private guest value, echoed in resp  */
  	blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
  	struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
  };
  struct blkif_x86_32_response {
  	uint64_t        id;              /* copied from request */
  	uint8_t         operation;       /* copied from request */
  	int16_t         status;          /* BLKIF_RSP_???       */
  };
  typedef struct blkif_x86_32_request blkif_x86_32_request_t;
  typedef struct blkif_x86_32_response blkif_x86_32_response_t;
  
  #pragma pack()
  
  /* x86_64 protocol version */
  struct blkif_x86_64_request {
  	uint8_t        operation;    /* BLKIF_OP_???                         */
  	uint8_t        nr_segments;  /* number of segments                   */
  	blkif_vdev_t   handle;       /* only for read/write requests         */
  #if defined(__GNUC__)
  	uint64_t       __attribute__((__aligned__(8))) id;
  #else
  	uint8_t        pad[4];
  	uint64_t       id;
  #endif
  	blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */
  	struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
  };
  struct blkif_x86_64_response {
  #if defined(__GNUC__)
  	uint64_t       __attribute__((__aligned__(8))) id;
  #else
  	uint64_t       id;
  #endif
  	uint8_t         operation;       /* copied from request */
  	int16_t         status;          /* BLKIF_RSP_???       */
  };
  typedef struct blkif_x86_64_request blkif_x86_64_request_t;
  typedef struct blkif_x86_64_response blkif_x86_64_response_t;
  
  DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request, struct blkif_x86_32_response);
  DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request, struct blkif_x86_64_response);
  
  enum blkif_protocol {
  	BLKIF_PROTOCOL_NATIVE = 1,
  	BLKIF_PROTOCOL_X86_32 = 2,
  	BLKIF_PROTOCOL_X86_64 = 3,
  };
  
  #define	BLKIF_RING_SIZE	\
  	__RING_SIZE((blkif_sring_t *)NULL, PAGESIZE)
  #define	BLKIF_X86_32_RING_SIZE \
  	__RING_SIZE((blkif_x86_32_sring_t *)NULL, PAGESIZE)
  #define	BLKIF_X86_64_RING_SIZE \
  	__RING_SIZE((blkif_x86_64_sring_t *)NULL, PAGESIZE)
  
  #endif /* __XEN_BLKIF_H__ */
  