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_ids.h> 7#include <linux/virtio_config.h> 8 9/* Feature bits */ 10#define VIRTIO_BLK_F_BARRIER 0 /* Does host support barriers? */ 11#define VIRTIO_BLK_F_SIZE_MAX 1 /* Indicates maximum segment size */ 12#define VIRTIO_BLK_F_SEG_MAX 2 /* Indicates maximum # of segments */ 13#define VIRTIO_BLK_F_GEOMETRY 4 /* Legacy geometry available */ 14#define VIRTIO_BLK_F_RO 5 /* Disk is read-only */ 15#define VIRTIO_BLK_F_BLK_SIZE 6 /* Block size of disk is available*/ 16#define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */ 17#define VIRTIO_BLK_F_FLUSH 9 /* Cache flush command support */ 18#define VIRTIO_BLK_F_TOPOLOGY 10 /* Topology information is available */ 19 20#define VIRTIO_BLK_ID_BYTES 20 /* ID string length */ 21 22struct virtio_blk_config { 23 /* The capacity (in 512-byte sectors). */ 24 __u64 capacity; 25 /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */ 26 __u32 size_max; 27 /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */ 28 __u32 seg_max; 29 /* geometry the device (if VIRTIO_BLK_F_GEOMETRY) */ 30 struct virtio_blk_geometry { 31 __u16 cylinders; 32 __u8 heads; 33 __u8 sectors; 34 } geometry; 35 36 /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */ 37 __u32 blk_size; 38 39 /* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY */ 40 /* exponent for physical block per logical block. */ 41 __u8 physical_block_exp; 42 /* alignment offset in logical blocks. */ 43 __u8 alignment_offset; 44 /* minimum I/O size without performance penalty in logical blocks. */ 45 __u16 min_io_size; 46 /* optimal sustained I/O size in logical blocks. */ 47 __u32 opt_io_size; 48 49} __attribute__((packed)); 50 51/* 52 * Command types 53 * 54 * Usage is a bit tricky as some bits are used as flags and some are not. 55 * 56 * Rules: 57 * VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or 58 * VIRTIO_BLK_T_BARRIER. VIRTIO_BLK_T_FLUSH is a command of its own 59 * and may not be combined with any of the other flags. 60 */ 61 62/* These two define direction. */ 63#define VIRTIO_BLK_T_IN 0 64#define VIRTIO_BLK_T_OUT 1 65 66/* This bit says it's a scsi command, not an actual read or write. */ 67#define VIRTIO_BLK_T_SCSI_CMD 2 68 69/* Cache flush command */ 70#define VIRTIO_BLK_T_FLUSH 4 71 72/* Get device ID command */ 73#define VIRTIO_BLK_T_GET_ID 8 74 75/* Barrier before this op. */ 76#define VIRTIO_BLK_T_BARRIER 0x80000000 77 78/* This is the first element of the read scatter-gather list. */ 79struct virtio_blk_outhdr { 80 /* VIRTIO_BLK_T* */ 81 __u32 type; 82 /* io priority. */ 83 __u32 ioprio; 84 /* Sector (ie. 512 byte offset) */ 85 __u64 sector; 86}; 87 88struct virtio_scsi_inhdr { 89 __u32 errors; 90 __u32 data_len; 91 __u32 sense_len; 92 __u32 residual; 93}; 94 95/* And this is the final byte of the write scatter-gather list. */ 96#define VIRTIO_BLK_S_OK 0 97#define VIRTIO_BLK_S_IOERR 1 98#define VIRTIO_BLK_S_UNSUPP 2 99#endif /* _LINUX_VIRTIO_BLK_H */ 100