virtio_blk.h (6948B)
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 "standard-headers/linux/types.h" 29 #include "standard-headers/linux/virtio_ids.h" 30 #include "standard-headers/linux/virtio_config.h" 31 #include "standard-headers/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 /* Old (deprecated) name for VIRTIO_BLK_F_FLUSH. */ 51 #define VIRTIO_BLK_F_WCE VIRTIO_BLK_F_FLUSH 52 #endif /* !VIRTIO_BLK_NO_LEGACY */ 53 54 #define VIRTIO_BLK_ID_BYTES 20 /* ID string length */ 55 56 struct virtio_blk_config { 57 /* The capacity (in 512-byte sectors). */ 58 __virtio64 capacity; 59 /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */ 60 __virtio32 size_max; 61 /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */ 62 __virtio32 seg_max; 63 /* geometry of the device (if VIRTIO_BLK_F_GEOMETRY) */ 64 struct virtio_blk_geometry { 65 __virtio16 cylinders; 66 uint8_t heads; 67 uint8_t sectors; 68 } geometry; 69 70 /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */ 71 __virtio32 blk_size; 72 73 /* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY */ 74 /* exponent for physical block per logical block. */ 75 uint8_t physical_block_exp; 76 /* alignment offset in logical blocks. */ 77 uint8_t alignment_offset; 78 /* minimum I/O size without performance penalty in logical blocks. */ 79 __virtio16 min_io_size; 80 /* optimal sustained I/O size in logical blocks. */ 81 __virtio32 opt_io_size; 82 83 /* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */ 84 uint8_t wce; 85 uint8_t unused; 86 87 /* number of vqs, only available when VIRTIO_BLK_F_MQ is set */ 88 __virtio16 num_queues; 89 90 /* the next 3 entries are guarded by VIRTIO_BLK_F_DISCARD */ 91 /* 92 * The maximum discard sectors (in 512-byte sectors) for 93 * one segment. 94 */ 95 __virtio32 max_discard_sectors; 96 /* 97 * The maximum number of discard segments in a 98 * discard command. 99 */ 100 __virtio32 max_discard_seg; 101 /* Discard commands must be aligned to this number of sectors. */ 102 __virtio32 discard_sector_alignment; 103 104 /* the next 3 entries are guarded by VIRTIO_BLK_F_WRITE_ZEROES */ 105 /* 106 * The maximum number of write zeroes sectors (in 512-byte sectors) in 107 * one segment. 108 */ 109 __virtio32 max_write_zeroes_sectors; 110 /* 111 * The maximum number of segments in a write zeroes 112 * command. 113 */ 114 __virtio32 max_write_zeroes_seg; 115 /* 116 * Set if a VIRTIO_BLK_T_WRITE_ZEROES request may result in the 117 * deallocation of one or more of the sectors. 118 */ 119 uint8_t write_zeroes_may_unmap; 120 121 uint8_t unused1[3]; 122 } QEMU_PACKED; 123 124 /* 125 * Command types 126 * 127 * Usage is a bit tricky as some bits are used as flags and some are not. 128 * 129 * Rules: 130 * VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or 131 * VIRTIO_BLK_T_BARRIER. VIRTIO_BLK_T_FLUSH is a command of its own 132 * and may not be combined with any of the other flags. 133 */ 134 135 /* These two define direction. */ 136 #define VIRTIO_BLK_T_IN 0 137 #define VIRTIO_BLK_T_OUT 1 138 139 #ifndef VIRTIO_BLK_NO_LEGACY 140 /* This bit says it's a scsi command, not an actual read or write. */ 141 #define VIRTIO_BLK_T_SCSI_CMD 2 142 #endif /* VIRTIO_BLK_NO_LEGACY */ 143 144 /* Cache flush command */ 145 #define VIRTIO_BLK_T_FLUSH 4 146 147 /* Get device ID command */ 148 #define VIRTIO_BLK_T_GET_ID 8 149 150 /* Discard command */ 151 #define VIRTIO_BLK_T_DISCARD 11 152 153 /* Write zeroes command */ 154 #define VIRTIO_BLK_T_WRITE_ZEROES 13 155 156 #ifndef VIRTIO_BLK_NO_LEGACY 157 /* Barrier before this op. */ 158 #define VIRTIO_BLK_T_BARRIER 0x80000000 159 #endif /* !VIRTIO_BLK_NO_LEGACY */ 160 161 /* 162 * This comes first in the read scatter-gather list. 163 * For legacy virtio, if VIRTIO_F_ANY_LAYOUT is not negotiated, 164 * this is the first element of the read scatter-gather list. 165 */ 166 struct virtio_blk_outhdr { 167 /* VIRTIO_BLK_T* */ 168 __virtio32 type; 169 /* io priority. */ 170 __virtio32 ioprio; 171 /* Sector (ie. 512 byte offset) */ 172 __virtio64 sector; 173 }; 174 175 /* Unmap this range (only valid for write zeroes command) */ 176 #define VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP 0x00000001 177 178 /* Discard/write zeroes range for each request. */ 179 struct virtio_blk_discard_write_zeroes { 180 /* discard/write zeroes start sector */ 181 uint64_t sector; 182 /* number of discard/write zeroes sectors */ 183 uint32_t num_sectors; 184 /* flags for this range */ 185 uint32_t flags; 186 }; 187 188 #ifndef VIRTIO_BLK_NO_LEGACY 189 struct virtio_scsi_inhdr { 190 __virtio32 errors; 191 __virtio32 data_len; 192 __virtio32 sense_len; 193 __virtio32 residual; 194 }; 195 #endif /* !VIRTIO_BLK_NO_LEGACY */ 196 197 /* And this is the final byte of the write scatter-gather list. */ 198 #define VIRTIO_BLK_S_OK 0 199 #define VIRTIO_BLK_S_IOERR 1 200 #define VIRTIO_BLK_S_UNSUPP 2 201 #endif /* _LINUX_VIRTIO_BLK_H */