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 #define VIRTIO_BLK_F_SCSI       7       /* Supports scsi command passthru */
  19 #define VIRTIO_BLK_F_IDENTIFY   8       /* ATA IDENTIFY supported */
  20
  21 #define VIRTIO_BLK_ID_BYTES     (sizeof(__u16[256]))    /* IDENTIFY DATA */
  22
  23 struct virtio_blk_config {
  24         /* The capacity (in 512-byte sectors). */
  25         __u64 capacity;
  26         /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
  27         __u32 size_max;
  28         /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
  29         __u32 seg_max;
  30         /* geometry the device (if VIRTIO_BLK_F_GEOMETRY) */
  31         struct virtio_blk_geometry {
  32                 __u16 cylinders;
  33                 __u8 heads;
  34                 __u8 sectors;
  35         } geometry;
  36         /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
  37         __u32 blk_size;
  38         __u8 identify[VIRTIO_BLK_ID_BYTES];
  39 } __attribute__((packed));
  40
  41 /* These two define direction. */
  42 #define VIRTIO_BLK_T_IN         0
  43 #define VIRTIO_BLK_T_OUT        1
  44
  45 /* This bit says it's a scsi command, not an actual read or write. */
  46 #define VIRTIO_BLK_T_SCSI_CMD   2
  47
  48 /* Barrier before this op. */
  49 #define VIRTIO_BLK_T_BARRIER    0x80000000
  50
  51 /* This is the first element of the read scatter-gather list. */
  52 struct virtio_blk_outhdr {
  53         /* VIRTIO_BLK_T* */
  54         __u32 type;
  55         /* io priority. */
  56         __u32 ioprio;
  57         /* Sector (ie. 512 byte offset) */
  58         __u64 sector;
  59 };
  60
  61 struct virtio_scsi_inhdr {
  62         __u32 errors;
  63         __u32 data_len;
  64         __u32 sense_len;
  65         __u32 residual;
  66 };
  67
  68 /* And this is the final byte of the write scatter-gather list. */
  69 #define VIRTIO_BLK_S_OK         0
  70 #define VIRTIO_BLK_S_IOERR      1
  71 #define VIRTIO_BLK_S_UNSUPP     2
  72 #endif /* _LINUX_VIRTIO_BLK_H */