include/linux/virtio_blk.h

   1 #ifndef _LINUX_VIRTIO_BLK_H
   2 #define _LINUX_VIRTIO_BLK_H
   3 /* This header is BSD licensed so anyone can use the definitions to implement
   4  * compatible drivers/servers. */
   5 #include <linux/types.h>
   6 #include <linux/virtio_config.h>
   7
   8 /* The ID for virtio_block */
   9 #define VIRTIO_ID_BLOCK 2
  10
  11 /* Feature bits */
  12 #define VIRTIO_BLK_F_BARRIER    0       /* Does host support barriers? */
  13 #define VIRTIO_BLK_F_SIZE_MAX   1       /* Indicates maximum segment size */
  14 #define VIRTIO_BLK_F_SEG_MAX    2       /* Indicates maximum # of segments */
  15 #define VIRTIO_BLK_F_GEOMETRY   4       /* Legacy geometry available  */
  16 #define VIRTIO_BLK_F_RO         5       /* Disk is read-only */
  17 #define VIRTIO_BLK_F_BLK_SIZE   6       /* Block size of disk is available*/
  18
  19 struct virtio_blk_config
  20 {
  21         /* The capacity (in 512-byte sectors). */
  22         __u64 capacity;
  23         /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
  24         __u32 size_max;
  25         /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
  26         __u32 seg_max;
  27         /* geometry the device (if VIRTIO_BLK_F_GEOMETRY) */
  28         struct virtio_blk_geometry {
  29                 __u16 cylinders;
  30                 __u8 heads;
  31                 __u8 sectors;
  32         } geometry;
  33         /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
  34         __u32 blk_size;
  35 } __attribute__((packed));
  36
  37 /* These two define direction. */
  38 #define VIRTIO_BLK_T_IN         0
  39 #define VIRTIO_BLK_T_OUT        1
  40
  41 /* This bit says it's a scsi command, not an actual read or write. */
  42 #define VIRTIO_BLK_T_SCSI_CMD   2
  43
  44 /* Barrier before this op. */
  45 #define VIRTIO_BLK_T_BARRIER    0x80000000
  46
  47 /* This is the first element of the read scatter-gather list. */
  48 struct virtio_blk_outhdr
  49 {
  50         /* VIRTIO_BLK_T* */
  51         __u32 type;
  52         /* io priority. */
  53         __u32 ioprio;
  54         /* Sector (ie. 512 byte offset) */
  55         __u64 sector;
  56 };
  57
  58 /* And this is the final byte of the write scatter-gather list. */
  59 #define VIRTIO_BLK_S_OK         0
  60 #define VIRTIO_BLK_S_IOERR      1
  61 #define VIRTIO_BLK_S_UNSUPP     2
  62 #endif /* _LINUX_VIRTIO_BLK_H */