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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_SIZE_MAX 1 /* Indicates maximum segment size */
35#define VIRTIO_BLK_F_SEG_MAX 2 /* Indicates maximum # of segments */
36#define VIRTIO_BLK_F_GEOMETRY 4 /* Legacy geometry available */
37#define VIRTIO_BLK_F_RO 5 /* Disk is read-only */
38#define VIRTIO_BLK_F_BLK_SIZE 6 /* Block size of disk is available*/
39#define VIRTIO_BLK_F_TOPOLOGY 10 /* Topology information is available */
40#define VIRTIO_BLK_F_MQ 12 /* support more than one vq */
41#define VIRTIO_BLK_F_DISCARD 13 /* DISCARD is supported */
42#define VIRTIO_BLK_F_WRITE_ZEROES 14 /* WRITE ZEROES is supported */
43#define VIRTIO_BLK_F_SECURE_ERASE 16 /* Secure Erase is supported */
44
45/* Legacy feature bits */
46#ifndef VIRTIO_BLK_NO_LEGACY
47#define VIRTIO_BLK_F_BARRIER 0 /* Does host support barriers? */
48#define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */
49#define VIRTIO_BLK_F_FLUSH 9 /* Flush command supported */
50#define VIRTIO_BLK_F_CONFIG_WCE 11 /* Writeback mode available in config */
51#ifndef __KERNEL__
52/* Old (deprecated) name for VIRTIO_BLK_F_FLUSH. */
53#define VIRTIO_BLK_F_WCE VIRTIO_BLK_F_FLUSH
54#endif
55#endif /* !VIRTIO_BLK_NO_LEGACY */
56
57#define VIRTIO_BLK_ID_BYTES 20 /* ID string length */
58
59struct virtio_blk_config {
60 /* The capacity (in 512-byte sectors). */
61 __virtio64 capacity;
62 /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
63 __virtio32 size_max;
64 /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
65 __virtio32 seg_max;
66 /* geometry of the device (if VIRTIO_BLK_F_GEOMETRY) */
67 struct virtio_blk_geometry {
68 __virtio16 cylinders;
69 __u8 heads;
70 __u8 sectors;
71 } geometry;
72
73 /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
74 __virtio32 blk_size;
75
76 /* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY */
77 /* exponent for physical block per logical block. */
78 __u8 physical_block_exp;
79 /* alignment offset in logical blocks. */
80 __u8 alignment_offset;
81 /* minimum I/O size without performance penalty in logical blocks. */
82 __virtio16 min_io_size;
83 /* optimal sustained I/O size in logical blocks. */
84 __virtio32 opt_io_size;
85
86 /* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */
87 __u8 wce;
88 __u8 unused;
89
90 /* number of vqs, only available when VIRTIO_BLK_F_MQ is set */
91 __virtio16 num_queues;
92
93 /* the next 3 entries are guarded by VIRTIO_BLK_F_DISCARD */
94 /*
95 * The maximum discard sectors (in 512-byte sectors) for
96 * one segment.
97 */
98 __virtio32 max_discard_sectors;
99 /*
100 * The maximum number of discard segments in a
101 * discard command.
102 */
103 __virtio32 max_discard_seg;
104 /* Discard commands must be aligned to this number of sectors. */
105 __virtio32 discard_sector_alignment;
106
107 /* the next 3 entries are guarded by VIRTIO_BLK_F_WRITE_ZEROES */
108 /*
109 * The maximum number of write zeroes sectors (in 512-byte sectors) in
110 * one segment.
111 */
112 __virtio32 max_write_zeroes_sectors;
113 /*
114 * The maximum number of segments in a write zeroes
115 * command.
116 */
117 __virtio32 max_write_zeroes_seg;
118 /*
119 * Set if a VIRTIO_BLK_T_WRITE_ZEROES request may result in the
120 * deallocation of one or more of the sectors.
121 */
122 __u8 write_zeroes_may_unmap;
123
124 __u8 unused1[3];
125
126 /* the next 3 entries are guarded by VIRTIO_BLK_F_SECURE_ERASE */
127 /*
128 * The maximum secure erase sectors (in 512-byte sectors) for
129 * one segment.
130 */
131 __virtio32 max_secure_erase_sectors;
132 /*
133 * The maximum number of secure erase segments in a
134 * secure erase command.
135 */
136 __virtio32 max_secure_erase_seg;
137 /* Secure erase commands must be aligned to this number of sectors. */
138 __virtio32 secure_erase_sector_alignment;
139
140} __attribute__((packed));
141
142/*
143 * Command types
144 *
145 * Usage is a bit tricky as some bits are used as flags and some are not.
146 *
147 * Rules:
148 * VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
149 * VIRTIO_BLK_T_BARRIER. VIRTIO_BLK_T_FLUSH is a command of its own
150 * and may not be combined with any of the other flags.
151 */
152
153/* These two define direction. */
154#define VIRTIO_BLK_T_IN 0
155#define VIRTIO_BLK_T_OUT 1
156
157#ifndef VIRTIO_BLK_NO_LEGACY
158/* This bit says it's a scsi command, not an actual read or write. */
159#define VIRTIO_BLK_T_SCSI_CMD 2
160#endif /* VIRTIO_BLK_NO_LEGACY */
161
162/* Cache flush command */
163#define VIRTIO_BLK_T_FLUSH 4
164
165/* Get device ID command */
166#define VIRTIO_BLK_T_GET_ID 8
167
168/* Discard command */
169#define VIRTIO_BLK_T_DISCARD 11
170
171/* Write zeroes command */
172#define VIRTIO_BLK_T_WRITE_ZEROES 13
173
174/* Secure erase command */
175#define VIRTIO_BLK_T_SECURE_ERASE 14
176
177#ifndef VIRTIO_BLK_NO_LEGACY
178/* Barrier before this op. */
179#define VIRTIO_BLK_T_BARRIER 0x80000000
180#endif /* !VIRTIO_BLK_NO_LEGACY */
181
182/*
183 * This comes first in the read scatter-gather list.
184 * For legacy virtio, if VIRTIO_F_ANY_LAYOUT is not negotiated,
185 * this is the first element of the read scatter-gather list.
186 */
187struct virtio_blk_outhdr {
188 /* VIRTIO_BLK_T* */
189 __virtio32 type;
190 /* io priority. */
191 __virtio32 ioprio;
192 /* Sector (ie. 512 byte offset) */
193 __virtio64 sector;
194};
195
196/* Unmap this range (only valid for write zeroes command) */
197#define VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP 0x00000001
198
199/* Discard/write zeroes range for each request. */
200struct virtio_blk_discard_write_zeroes {
201 /* discard/write zeroes start sector */
202 __le64 sector;
203 /* number of discard/write zeroes sectors */
204 __le32 num_sectors;
205 /* flags for this range */
206 __le32 flags;
207};
208
209#ifndef VIRTIO_BLK_NO_LEGACY
210struct virtio_scsi_inhdr {
211 __virtio32 errors;
212 __virtio32 data_len;
213 __virtio32 sense_len;
214 __virtio32 residual;
215};
216#endif /* !VIRTIO_BLK_NO_LEGACY */
217
218/* And this is the final byte of the write scatter-gather list. */
219#define VIRTIO_BLK_S_OK 0
220#define VIRTIO_BLK_S_IOERR 1
221#define VIRTIO_BLK_S_UNSUPP 2
222#endif /* _LINUX_VIRTIO_BLK_H */