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 */ 204