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
44 /* Legacy feature bits */
45 #ifndef VIRTIO_BLK_NO_LEGACY
46 #define VIRTIO_BLK_F_BARRIER 0 /* Does host support barriers? */
47 #define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */
48 #define VIRTIO_BLK_F_FLUSH 9 /* Flush command supported */
49 #define VIRTIO_BLK_F_CONFIG_WCE 11 /* Writeback mode available in config */
50 #ifndef __KERNEL__
51 /* Old (deprecated) name for VIRTIO_BLK_F_FLUSH. */
52 #define VIRTIO_BLK_F_WCE VIRTIO_BLK_F_FLUSH
53 #endif
54 #endif /* !VIRTIO_BLK_NO_LEGACY */
55
56 #define VIRTIO_BLK_ID_BYTES 20 /* ID string length */
57
58 struct virtio_blk_config {
59 /* The capacity (in 512-byte sectors). */
60 __u64 capacity;
61 /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
62 __u32 size_max;
63 /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
64 __u32 seg_max;
65 /* geometry of the device (if VIRTIO_BLK_F_GEOMETRY) */
66 struct virtio_blk_geometry {
67 __u16 cylinders;
68 __u8 heads;
69 __u8 sectors;
70 } geometry;
71
72 /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
73 __u32 blk_size;
74
75 /* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY */
76 /* exponent for physical block per logical block. */
77 __u8 physical_block_exp;
78 /* alignment offset in logical blocks. */
79 __u8 alignment_offset;
80 /* minimum I/O size without performance penalty in logical blocks. */
81 __u16 min_io_size;
82 /* optimal sustained I/O size in logical blocks. */
83 __u32 opt_io_size;
84
85 /* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */
86 __u8 wce;
87 __u8 unused;
88
89 /* number of vqs, only available when VIRTIO_BLK_F_MQ is set */
90 __u16 num_queues;
91
92 /* the next 3 entries are guarded by VIRTIO_BLK_F_DISCARD */
93 /*
94 * The maximum discard sectors (in 512-byte sectors) for
95 * one segment.
96 */
97 __u32 max_discard_sectors;
98 /*
99 * The maximum number of discard segments in a
100 * discard command.
101 */
102 __u32 max_discard_seg;
103 /* Discard commands must be aligned to this number of sectors. */
104 __u32 discard_sector_alignment;
105
106 /* the next 3 entries are guarded by VIRTIO_BLK_F_WRITE_ZEROES */
107 /*
108 * The maximum number of write zeroes sectors (in 512-byte sectors) in
109 * one segment.
110 */
111 __u32 max_write_zeroes_sectors;
112 /*
113 * The maximum number of segments in a write zeroes
114 * command.
115 */
116 __u32 max_write_zeroes_seg;
117 /*
118 * Set if a VIRTIO_BLK_T_WRITE_ZEROES request may result in the
119 * deallocation of one or more of the sectors.
120 */
121 __u8 write_zeroes_may_unmap;
122
123 __u8 unused1[3];
124 } __attribute__((packed));
125
126 /*
127 * Command types
128 *
129 * Usage is a bit tricky as some bits are used as flags and some are not.
130 *
131 * Rules:
132 * VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
133 * VIRTIO_BLK_T_BARRIER. VIRTIO_BLK_T_FLUSH is a command of its own
134 * and may not be combined with any of the other flags.
135 */
136
137 /* These two define direction. */
138 #define VIRTIO_BLK_T_IN 0
139 #define VIRTIO_BLK_T_OUT 1
140
141 #ifndef VIRTIO_BLK_NO_LEGACY
142 /* This bit says it's a scsi command, not an actual read or write. */
143 #define VIRTIO_BLK_T_SCSI_CMD 2
144 #endif /* VIRTIO_BLK_NO_LEGACY */
145
146 /* Cache flush command */
147 #define VIRTIO_BLK_T_FLUSH 4
148
149 /* Get device ID command */
150 #define VIRTIO_BLK_T_GET_ID 8
151
152 /* Discard command */
153 #define VIRTIO_BLK_T_DISCARD 11
154
155 /* Write zeroes command */
156 #define VIRTIO_BLK_T_WRITE_ZEROES 13
157
158 #ifndef VIRTIO_BLK_NO_LEGACY
159 /* Barrier before this op. */
160 #define VIRTIO_BLK_T_BARRIER 0x80000000
161 #endif /* !VIRTIO_BLK_NO_LEGACY */
162
163 /*
164 * This comes first in the read scatter-gather list.
165 * For legacy virtio, if VIRTIO_F_ANY_LAYOUT is not negotiated,
166 * this is the first element of the read scatter-gather list.
167 */
168 struct virtio_blk_outhdr {
169 /* VIRTIO_BLK_T* */
170 __virtio32 type;
171 /* io priority. */
172 __virtio32 ioprio;
173 /* Sector (ie. 512 byte offset) */
174 __virtio64 sector;
175 };
176
177 /* Unmap this range (only valid for write zeroes command) */
178 #define VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP 0x00000001
179
180 /* Discard/write zeroes range for each request. */
181 struct virtio_blk_discard_write_zeroes {
182 /* discard/write zeroes start sector */
183 __le64 sector;
184 /* number of discard/write zeroes sectors */
185 __le32 num_sectors;
186 /* flags for this range */
187 __le32 flags;
188 };
189
190 #ifndef VIRTIO_BLK_NO_LEGACY
191 struct virtio_scsi_inhdr {
192 __virtio32 errors;
193 __virtio32 data_len;
194 __virtio32 sense_len;
195 __virtio32 residual;
196 };
197 #endif /* !VIRTIO_BLK_NO_LEGACY */
198
199 /* And this is the final byte of the write scatter-gather list. */
200 #define VIRTIO_BLK_S_OK 0
201 #define VIRTIO_BLK_S_IOERR 1
202 #define VIRTIO_BLK_S_UNSUPP 2
203 #endif /* _LINUX_VIRTIO_BLK_H */