Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of IBM nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE. */
28#include <linux/types.h>
29#include <linux/virtio_ids.h>
30#include <linux/virtio_config.h>
31#include <linux/virtio_types.h>
32
33/* Feature bits */
34#define VIRTIO_BLK_F_BARRIER 0 /* Does host support barriers? */
35#define VIRTIO_BLK_F_SIZE_MAX 1 /* Indicates maximum segment size */
36#define VIRTIO_BLK_F_SEG_MAX 2 /* Indicates maximum # of segments */
37#define VIRTIO_BLK_F_GEOMETRY 4 /* Legacy geometry available */
38#define VIRTIO_BLK_F_RO 5 /* Disk is read-only */
39#define VIRTIO_BLK_F_BLK_SIZE 6 /* Block size of disk is available*/
40#define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */
41#define VIRTIO_BLK_F_WCE 9 /* Writeback mode enabled after reset */
42#define VIRTIO_BLK_F_TOPOLOGY 10 /* Topology information is available */
43#define VIRTIO_BLK_F_CONFIG_WCE 11 /* Writeback mode available in config */
44#define VIRTIO_BLK_F_MQ 12 /* support more than one vq */
45
46#ifndef __KERNEL__
47/* Old (deprecated) name for VIRTIO_BLK_F_WCE. */
48#define VIRTIO_BLK_F_FLUSH VIRTIO_BLK_F_WCE
49#endif
50
51#define VIRTIO_BLK_ID_BYTES 20 /* ID string length */
52
53struct virtio_blk_config {
54 /* The capacity (in 512-byte sectors). */
55 __u64 capacity;
56 /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
57 __u32 size_max;
58 /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
59 __u32 seg_max;
60 /* geometry the device (if VIRTIO_BLK_F_GEOMETRY) */
61 struct virtio_blk_geometry {
62 __u16 cylinders;
63 __u8 heads;
64 __u8 sectors;
65 } geometry;
66
67 /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
68 __u32 blk_size;
69
70 /* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY */
71 /* exponent for physical block per logical block. */
72 __u8 physical_block_exp;
73 /* alignment offset in logical blocks. */
74 __u8 alignment_offset;
75 /* minimum I/O size without performance penalty in logical blocks. */
76 __u16 min_io_size;
77 /* optimal sustained I/O size in logical blocks. */
78 __u32 opt_io_size;
79
80 /* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */
81 __u8 wce;
82 __u8 unused;
83
84 /* number of vqs, only available when VIRTIO_BLK_F_MQ is set */
85 __u16 num_queues;
86} __attribute__((packed));
87
88/*
89 * Command types
90 *
91 * Usage is a bit tricky as some bits are used as flags and some are not.
92 *
93 * Rules:
94 * VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
95 * VIRTIO_BLK_T_BARRIER. VIRTIO_BLK_T_FLUSH is a command of its own
96 * and may not be combined with any of the other flags.
97 */
98
99/* These two define direction. */
100#define VIRTIO_BLK_T_IN 0
101#define VIRTIO_BLK_T_OUT 1
102
103/* This bit says it's a scsi command, not an actual read or write. */
104#define VIRTIO_BLK_T_SCSI_CMD 2
105
106/* Cache flush command */
107#define VIRTIO_BLK_T_FLUSH 4
108
109/* Get device ID command */
110#define VIRTIO_BLK_T_GET_ID 8
111
112/* Barrier before this op. */
113#define VIRTIO_BLK_T_BARRIER 0x80000000
114
115/* This is the first element of the read scatter-gather list. */
116struct virtio_blk_outhdr {
117 /* VIRTIO_BLK_T* */
118 __virtio32 type;
119 /* io priority. */
120 __virtio32 ioprio;
121 /* Sector (ie. 512 byte offset) */
122 __virtio64 sector;
123};
124
125struct virtio_scsi_inhdr {
126 __virtio32 errors;
127 __virtio32 data_len;
128 __virtio32 sense_len;
129 __virtio32 residual;
130};
131
132/* And this is the final byte of the write scatter-gather list. */
133#define VIRTIO_BLK_S_OK 0
134#define VIRTIO_BLK_S_IOERR 1
135#define VIRTIO_BLK_S_UNSUPP 2
136#endif /* _LINUX_VIRTIO_BLK_H */