2 * SPDX-License-Identifier: BSD-3-Clause
4 * This header is BSD licensed so anyone can use the definitions to implement
5 * compatible drivers/servers.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of IBM nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
20 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
21 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 #define VTBLK_BSIZE 512
40 #define VIRTIO_BLK_F_BARRIER 0x0001 /* Does host support barriers? */
41 #define VIRTIO_BLK_F_SIZE_MAX 0x0002 /* Indicates maximum segment size */
42 #define VIRTIO_BLK_F_SEG_MAX 0x0004 /* Indicates maximum # of segments */
43 #define VIRTIO_BLK_F_GEOMETRY 0x0010 /* Legacy geometry available */
44 #define VIRTIO_BLK_F_RO 0x0020 /* Disk is read-only */
45 #define VIRTIO_BLK_F_BLK_SIZE 0x0040 /* Block size of disk is available*/
46 #define VIRTIO_BLK_F_SCSI 0x0080 /* Supports scsi command passthru */
47 #define VIRTIO_BLK_F_FLUSH 0x0200 /* Flush command supported */
48 #define VIRTIO_BLK_F_WCE 0x0200 /* Legacy alias for FLUSH */
49 #define VIRTIO_BLK_F_TOPOLOGY 0x0400 /* Topology information is available */
50 #define VIRTIO_BLK_F_CONFIG_WCE 0x0800 /* Writeback mode available in config */
51 #define VIRTIO_BLK_F_MQ 0x1000 /* Support more than one vq */
52 #define VIRTIO_BLK_F_DISCARD 0x2000 /* Trim blocks */
53 #define VIRTIO_BLK_F_WRITE_ZEROES 0x4000 /* Write zeros */
55 #define VIRTIO_BLK_ID_BYTES 20 /* ID string length */
57 struct virtio_blk_config {
58 /* The capacity (in 512-byte sectors). */
60 /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
62 /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
64 /* Geometry of the device (if VIRTIO_BLK_F_GEOMETRY) */
65 struct virtio_blk_geometry {
71 /* Block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
74 /* Topology of the device (if VIRTIO_BLK_F_TOPOLOGY) */
75 struct virtio_blk_topology {
76 /* Exponent for physical block per logical block. */
77 uint8_t physical_block_exp;
78 /* Alignment offset in logical blocks. */
79 uint8_t alignment_offset;
80 /* Minimum I/O size without performance penalty in logical
83 /* Optimal sustained I/O size in logical blocks. */
87 /* Writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */
90 /* Number of vqs, only available when VIRTIO_BLK_F_MQ is set */
92 uint32_t max_discard_sectors;
93 uint32_t max_discard_seg;
94 uint32_t discard_sector_alignment;
95 uint32_t max_write_zeroes_sectors;
96 uint32_t max_write_zeroes_seg;
97 uint8_t write_zeroes_may_unmap;
104 * Usage is a bit tricky as some bits are used as flags and some are not.
107 * VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
108 * VIRTIO_BLK_T_BARRIER. VIRTIO_BLK_T_FLUSH is a command of its own
109 * and may not be combined with any of the other flags.
112 /* These two define direction. */
113 #define VIRTIO_BLK_T_IN 0
114 #define VIRTIO_BLK_T_OUT 1
116 /* This bit says it's a scsi command, not an actual read or write. */
117 #define VIRTIO_BLK_T_SCSI_CMD 2
118 #define VIRTIO_BLK_T_SCSI_CMD_OUT 3
120 /* Cache flush command */
121 #define VIRTIO_BLK_T_FLUSH 4
122 #define VIRTIO_BLK_T_FLUSH_OUT 5
124 /* Get device ID command */
125 #define VIRTIO_BLK_T_GET_ID 8
127 /* Discard command */
128 #define VIRTIO_BLK_T_DISCARD 11
130 /* Write zeros command */
131 #define VIRTIO_BLK_T_WRITE_ZEROES 13
133 /* Barrier before this op. */
134 #define VIRTIO_BLK_T_BARRIER 0x80000000
136 /* ID string length */
137 #define VIRTIO_BLK_ID_BYTES 20
139 /* Unmap this range (only valid for write zeroes command) */
140 #define VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP 0x00000001
142 /* This is the first element of the read scatter-gather list. */
143 struct virtio_blk_outhdr {
148 /* Sector (ie. 512 byte offset) */
152 struct virtio_blk_discard_write_zeroes {
154 uint32_t num_sectors;
157 uint32_t reserved:31;
161 struct virtio_scsi_inhdr {
168 /* And this is the final byte of the write scatter-gather list. */
169 #define VIRTIO_BLK_S_OK 0
170 #define VIRTIO_BLK_S_IOERR 1
171 #define VIRTIO_BLK_S_UNSUPP 2
173 #endif /* _VIRTIO_BLK_H */