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