aboutsummaryrefslogtreecommitdiff
path: root/include/standard-headers/linux/virtio_blk.h
blob: 2dcc90826ae7d30ccc7169355b43800c21551214 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
#ifndef _LINUX_VIRTIO_BLK_H
#define _LINUX_VIRTIO_BLK_H
/* This header is BSD licensed so anyone can use the definitions to implement
 * compatible drivers/servers.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of IBM nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE. */
#include "standard-headers/linux/types.h"
#include "standard-headers/linux/virtio_ids.h"
#include "standard-headers/linux/virtio_config.h"
#include "standard-headers/linux/virtio_types.h"

/* Feature bits */
#define VIRTIO_BLK_F_SIZE_MAX	1	/* Indicates maximum segment size */
#define VIRTIO_BLK_F_SEG_MAX	2	/* Indicates maximum # of segments */
#define VIRTIO_BLK_F_GEOMETRY	4	/* Legacy geometry available  */
#define VIRTIO_BLK_F_RO		5	/* Disk is read-only */
#define VIRTIO_BLK_F_BLK_SIZE	6	/* Block size of disk is available*/
#define VIRTIO_BLK_F_TOPOLOGY	10	/* Topology information is available */
#define VIRTIO_BLK_F_MQ		12	/* support more than one vq */
#define VIRTIO_BLK_F_DISCARD	13	/* DISCARD is supported */
#define VIRTIO_BLK_F_WRITE_ZEROES	14	/* WRITE ZEROES is supported */

/* Legacy feature bits */
#ifndef VIRTIO_BLK_NO_LEGACY
#define VIRTIO_BLK_F_BARRIER	0	/* Does host support barriers? */
#define VIRTIO_BLK_F_SCSI	7	/* Supports scsi command passthru */
#define VIRTIO_BLK_F_FLUSH	9	/* Flush command supported */
#define VIRTIO_BLK_F_CONFIG_WCE	11	/* Writeback mode available in config */
/* Old (deprecated) name for VIRTIO_BLK_F_FLUSH. */
#define VIRTIO_BLK_F_WCE VIRTIO_BLK_F_FLUSH
#endif /* !VIRTIO_BLK_NO_LEGACY */

#define VIRTIO_BLK_ID_BYTES	20	/* ID string length */

struct virtio_blk_config {
	/* The capacity (in 512-byte sectors). */
	__virtio64 capacity;
	/* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
	__virtio32 size_max;
	/* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
	__virtio32 seg_max;
	/* geometry of the device (if VIRTIO_BLK_F_GEOMETRY) */
	struct virtio_blk_geometry {
		__virtio16 cylinders;
		uint8_t heads;
		uint8_t sectors;
	} geometry;

	/* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
	__virtio32 blk_size;

	/* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY  */
	/* exponent for physical block per logical block. */
	uint8_t physical_block_exp;
	/* alignment offset in logical blocks. */
	uint8_t alignment_offset;
	/* minimum I/O size without performance penalty in logical blocks. */
	__virtio16 min_io_size;
	/* optimal sustained I/O size in logical blocks. */
	__virtio32 opt_io_size;

	/* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */
	uint8_t wce;
	uint8_t unused;

	/* number of vqs, only available when VIRTIO_BLK_F_MQ is set */
	__virtio16 num_queues;

	/* the next 3 entries are guarded by VIRTIO_BLK_F_DISCARD */
	/*
	 * The maximum discard sectors (in 512-byte sectors) for
	 * one segment.
	 */
	__virtio32 max_discard_sectors;
	/*
	 * The maximum number of discard segments in a
	 * discard command.
	 */
	__virtio32 max_discard_seg;
	/* Discard commands must be aligned to this number of sectors. */
	__virtio32 discard_sector_alignment;

	/* the next 3 entries are guarded by VIRTIO_BLK_F_WRITE_ZEROES */
	/*
	 * The maximum number of write zeroes sectors (in 512-byte sectors) in
	 * one segment.
	 */
	__virtio32 max_write_zeroes_sectors;
	/*
	 * The maximum number of segments in a write zeroes
	 * command.
	 */
	__virtio32 max_write_zeroes_seg;
	/*
	 * Set if a VIRTIO_BLK_T_WRITE_ZEROES request may result in the
	 * deallocation of one or more of the sectors.
	 */
	uint8_t write_zeroes_may_unmap;

	uint8_t unused1[3];
} QEMU_PACKED;

/*
 * Command types
 *
 * Usage is a bit tricky as some bits are used as flags and some are not.
 *
 * Rules:
 *   VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
 *   VIRTIO_BLK_T_BARRIER.  VIRTIO_BLK_T_FLUSH is a command of its own
 *   and may not be combined with any of the other flags.
 */

/* These two define direction. */
#define VIRTIO_BLK_T_IN		0
#define VIRTIO_BLK_T_OUT	1

#ifndef VIRTIO_BLK_NO_LEGACY
/* This bit says it's a scsi command, not an actual read or write. */
#define VIRTIO_BLK_T_SCSI_CMD	2
#endif /* VIRTIO_BLK_NO_LEGACY */

/* Cache flush command */
#define VIRTIO_BLK_T_FLUSH	4

/* Get device ID command */
#define VIRTIO_BLK_T_GET_ID    8

/* Discard command */
#define VIRTIO_BLK_T_DISCARD	11

/* Write zeroes command */
#define VIRTIO_BLK_T_WRITE_ZEROES	13

#ifndef VIRTIO_BLK_NO_LEGACY
/* Barrier before this op. */
#define VIRTIO_BLK_T_BARRIER	0x80000000
#endif /* !VIRTIO_BLK_NO_LEGACY */

/*
 * This comes first in the read scatter-gather list.
 * For legacy virtio, if VIRTIO_F_ANY_LAYOUT is not negotiated,
 * this is the first element of the read scatter-gather list.
 */
struct virtio_blk_outhdr {
	/* VIRTIO_BLK_T* */
	__virtio32 type;
	/* io priority. */
	__virtio32 ioprio;
	/* Sector (ie. 512 byte offset) */
	__virtio64 sector;
};

/* Unmap this range (only valid for write zeroes command) */
#define VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP	0x00000001

/* Discard/write zeroes range for each request. */
struct virtio_blk_discard_write_zeroes {
	/* discard/write zeroes start sector */
	uint64_t sector;
	/* number of discard/write zeroes sectors */
	uint32_t num_sectors;
	/* flags for this range */
	uint32_t flags;
};

#ifndef VIRTIO_BLK_NO_LEGACY
struct virtio_scsi_inhdr {
	__virtio32 errors;
	__virtio32 data_len;
	__virtio32 sense_len;
	__virtio32 residual;
};
#endif /* !VIRTIO_BLK_NO_LEGACY */

/* And this is the final byte of the write scatter-gather list. */
#define VIRTIO_BLK_S_OK		0
#define VIRTIO_BLK_S_IOERR	1
#define VIRTIO_BLK_S_UNSUPP	2
#endif /* _LINUX_VIRTIO_BLK_H */