include/standard-headers/linux/virtio_blk.h

   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 #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 /* Old (deprecated) name for VIRTIO_BLK_F_FLUSH. */
  52 #define VIRTIO_BLK_F_WCE VIRTIO_BLK_F_FLUSH
  53 #endif /* !VIRTIO_BLK_NO_LEGACY */
  54
  55 #define VIRTIO_BLK_ID_BYTES     20      /* ID string length */
  56
  57 struct virtio_blk_config {
  58         /* The capacity (in 512-byte sectors). */
  59         __virtio64 capacity;
  60         /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
  61         __virtio32 size_max;
  62         /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
  63         __virtio32 seg_max;
  64         /* geometry of the device (if VIRTIO_BLK_F_GEOMETRY) */
  65         struct virtio_blk_geometry {
  66                 __virtio16 cylinders;
  67                 uint8_t heads;
  68                 uint8_t sectors;
  69         } geometry;
  70
  71         /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
  72         __virtio32 blk_size;
  73
  74         /* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY  */
  75         /* exponent for physical block per logical block. */
  76         uint8_t physical_block_exp;
  77         /* alignment offset in logical blocks. */
  78         uint8_t alignment_offset;
  79         /* minimum I/O size without performance penalty in logical blocks. */
  80         __virtio16 min_io_size;
  81         /* optimal sustained I/O size in logical blocks. */
  82         __virtio32 opt_io_size;
  83
  84         /* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */
  85         uint8_t wce;
  86         uint8_t unused;
  87
  88         /* number of vqs, only available when VIRTIO_BLK_F_MQ is set */
  89         __virtio16 num_queues;
  90
  91         /* the next 3 entries are guarded by VIRTIO_BLK_F_DISCARD */
  92         /*
  93          * The maximum discard sectors (in 512-byte sectors) for
  94          * one segment.
  95          */
  96         __virtio32 max_discard_sectors;
  97         /*
  98          * The maximum number of discard segments in a
  99          * discard command.
 100          */
 101         __virtio32 max_discard_seg;
 102         /* Discard commands must be aligned to this number of sectors. */
 103         __virtio32 discard_sector_alignment;
 104
 105         /* the next 3 entries are guarded by VIRTIO_BLK_F_WRITE_ZEROES */
 106         /*
 107          * The maximum number of write zeroes sectors (in 512-byte sectors) in
 108          * one segment.
 109          */
 110         __virtio32 max_write_zeroes_sectors;
 111         /*
 112          * The maximum number of segments in a write zeroes
 113          * command.
 114          */
 115         __virtio32 max_write_zeroes_seg;
 116         /*
 117          * Set if a VIRTIO_BLK_T_WRITE_ZEROES request may result in the
 118          * deallocation of one or more of the sectors.
 119          */
 120         uint8_t write_zeroes_may_unmap;
 121
 122         uint8_t unused1[3];
 123
 124         /* the next 3 entries are guarded by VIRTIO_BLK_F_SECURE_ERASE */
 125         /*
 126          * The maximum secure erase sectors (in 512-byte sectors) for
 127          * one segment.
 128          */
 129         __virtio32 max_secure_erase_sectors;
 130         /*
 131          * The maximum number of secure erase segments in a
 132          * secure erase command.
 133          */
 134         __virtio32 max_secure_erase_seg;
 135         /* Secure erase commands must be aligned to this number of sectors. */
 136         __virtio32 secure_erase_sector_alignment;
 137
 138 } QEMU_PACKED;
 139
 140 /*
 141  * Command types
 142  *
 143  * Usage is a bit tricky as some bits are used as flags and some are not.
 144  *
 145  * Rules:
 146  *   VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
 147  *   VIRTIO_BLK_T_BARRIER.  VIRTIO_BLK_T_FLUSH is a command of its own
 148  *   and may not be combined with any of the other flags.
 149  */
 150
 151 /* These two define direction. */
 152 #define VIRTIO_BLK_T_IN         0
 153 #define VIRTIO_BLK_T_OUT        1
 154
 155 #ifndef VIRTIO_BLK_NO_LEGACY
 156 /* This bit says it's a scsi command, not an actual read or write. */
 157 #define VIRTIO_BLK_T_SCSI_CMD   2
 158 #endif /* VIRTIO_BLK_NO_LEGACY */
 159
 160 /* Cache flush command */
 161 #define VIRTIO_BLK_T_FLUSH      4
 162
 163 /* Get device ID command */
 164 #define VIRTIO_BLK_T_GET_ID    8
 165
 166 /* Discard command */
 167 #define VIRTIO_BLK_T_DISCARD    11
 168
 169 /* Write zeroes command */
 170 #define VIRTIO_BLK_T_WRITE_ZEROES       13
 171
 172 /* Secure erase command */
 173 #define VIRTIO_BLK_T_SECURE_ERASE       14
 174
 175 #ifndef VIRTIO_BLK_NO_LEGACY
 176 /* Barrier before this op. */
 177 #define VIRTIO_BLK_T_BARRIER    0x80000000
 178 #endif /* !VIRTIO_BLK_NO_LEGACY */
 179
 180 /*
 181  * This comes first in the read scatter-gather list.
 182  * For legacy virtio, if VIRTIO_F_ANY_LAYOUT is not negotiated,
 183  * this is the first element of the read scatter-gather list.
 184  */
 185 struct virtio_blk_outhdr {
 186         /* VIRTIO_BLK_T* */
 187         __virtio32 type;
 188         /* io priority. */
 189         __virtio32 ioprio;
 190         /* Sector (ie. 512 byte offset) */
 191         __virtio64 sector;
 192 };
 193
 194 /* Unmap this range (only valid for write zeroes command) */
 195 #define VIRTIO_BLK_WRITE_ZEROES_FLAG_UNMAP      0x00000001
 196
 197 /* Discard/write zeroes range for each request. */
 198 struct virtio_blk_discard_write_zeroes {
 199         /* discard/write zeroes start sector */
 200         uint64_t sector;
 201         /* number of discard/write zeroes sectors */
 202         uint32_t num_sectors;
 203         /* flags for this range */
 204         uint32_t flags;
 205 };
 206
 207 #ifndef VIRTIO_BLK_NO_LEGACY
 208 struct virtio_scsi_inhdr {
 209         __virtio32 errors;
 210         __virtio32 data_len;
 211         __virtio32 sense_len;
 212         __virtio32 residual;
 213 };
 214 #endif /* !VIRTIO_BLK_NO_LEGACY */
 215
 216 /* And this is the final byte of the write scatter-gather list. */
 217 #define VIRTIO_BLK_S_OK         0
 218 #define VIRTIO_BLK_S_IOERR      1
 219 #define VIRTIO_BLK_S_UNSUPP     2
 220 #endif /* _LINUX_VIRTIO_BLK_H */