include/linux/virtio_blk.h

   1 #ifndef _LINUX_VIRTIO_BLK_H
   2 #define _LINUX_VIRTIO_BLK_H
   3 #include <linux/virtio_config.h>
   4
   5 /* The ID for virtio_block */
   6 #define VIRTIO_ID_BLOCK 2
   7
   8 /* Feature bits */
   9 #define VIRTIO_BLK_F_BARRIER    0       /* Does host support barriers? */
  10 #define VIRTIO_BLK_F_SIZE_MAX   1       /* Indicates maximum segment size */
  11 #define VIRTIO_BLK_F_SEG_MAX    2       /* Indicates maximum # of segments */
  12 #define VIRTIO_BLK_F_GEOMETRY   4       /* Legacy geometry available  */
  13 #define VIRTIO_BLK_F_RO         5       /* Disk is read-only */
  14
  15 struct virtio_blk_config
  16 {
  17         /* The capacity (in 512-byte sectors). */
  18         __u64 capacity;
  19         /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
  20         __u32 size_max;
  21         /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
  22         __u32 seg_max;
  23         /* geometry the device (if VIRTIO_BLK_F_GEOMETRY) */
  24         struct virtio_blk_geometry {
  25                 __u16 cylinders;
  26                 __u8 heads;
  27                 __u8 sectors;
  28         } geometry;
  29 } __attribute__((packed));
  30
  31 /* These two define direction. */
  32 #define VIRTIO_BLK_T_IN         0
  33 #define VIRTIO_BLK_T_OUT        1
  34
  35 /* This bit says it's a scsi command, not an actual read or write. */
  36 #define VIRTIO_BLK_T_SCSI_CMD   2
  37
  38 /* Barrier before this op. */
  39 #define VIRTIO_BLK_T_BARRIER    0x80000000
  40
  41 /* This is the first element of the read scatter-gather list. */
  42 struct virtio_blk_outhdr
  43 {
  44         /* VIRTIO_BLK_T* */
  45         __u32 type;
  46         /* io priority. */
  47         __u32 ioprio;
  48         /* Sector (ie. 512 byte offset) */
  49         __u64 sector;
  50 };
  51
  52 /* And this is the final byte of the write scatter-gather list. */
  53 #define VIRTIO_BLK_S_OK         0
  54 #define VIRTIO_BLK_S_IOERR      1
  55 #define VIRTIO_BLK_S_UNSUPP     2
  56 #endif /* _LINUX_VIRTIO_BLK_H */