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
  42 /* Legacy feature bits */
  43 #ifndef VIRTIO_BLK_NO_LEGACY
  44 #define VIRTIO_BLK_F_BARRIER    0       /* Does host support barriers? */
  45 #define VIRTIO_BLK_F_SCSI       7       /* Supports scsi command passthru */
  46 #define VIRTIO_BLK_F_FLUSH      9       /* Flush command supported */
  47 #define VIRTIO_BLK_F_CONFIG_WCE 11      /* Writeback mode available in config */
  48 /* Old (deprecated) name for VIRTIO_BLK_F_FLUSH. */
  49 #define VIRTIO_BLK_F_WCE VIRTIO_BLK_F_FLUSH
  50 #endif /* !VIRTIO_BLK_NO_LEGACY */
  51
  52 #define VIRTIO_BLK_ID_BYTES     20      /* ID string length */
  53
  54 struct virtio_blk_config {
  55         /* The capacity (in 512-byte sectors). */
  56         uint64_t capacity;
  57         /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
  58         uint32_t size_max;
  59         /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
  60         uint32_t seg_max;
  61         /* geometry of the device (if VIRTIO_BLK_F_GEOMETRY) */
  62         struct virtio_blk_geometry {
  63                 uint16_t cylinders;
  64                 uint8_t heads;
  65                 uint8_t sectors;
  66         } geometry;
  67
  68         /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
  69         uint32_t blk_size;
  70
  71         /* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY  */
  72         /* exponent for physical block per logical block. */
  73         uint8_t physical_block_exp;
  74         /* alignment offset in logical blocks. */
  75         uint8_t alignment_offset;
  76         /* minimum I/O size without performance penalty in logical blocks. */
  77         uint16_t min_io_size;
  78         /* optimal sustained I/O size in logical blocks. */
  79         uint32_t opt_io_size;
  80
  81         /* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */
  82         uint8_t wce;
  83         uint8_t unused;
  84
  85         /* number of vqs, only available when VIRTIO_BLK_F_MQ is set */
  86         uint16_t num_queues;
  87 } QEMU_PACKED;
  88
  89 /*
  90  * Command types
  91  *
  92  * Usage is a bit tricky as some bits are used as flags and some are not.
  93  *
  94  * Rules:
  95  *   VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
  96  *   VIRTIO_BLK_T_BARRIER.  VIRTIO_BLK_T_FLUSH is a command of its own
  97  *   and may not be combined with any of the other flags.
  98  */
  99
 100 /* These two define direction. */
 101 #define VIRTIO_BLK_T_IN         0
 102 #define VIRTIO_BLK_T_OUT        1
 103
 104 #ifndef VIRTIO_BLK_NO_LEGACY
 105 /* This bit says it's a scsi command, not an actual read or write. */
 106 #define VIRTIO_BLK_T_SCSI_CMD   2
 107 #endif /* VIRTIO_BLK_NO_LEGACY */
 108
 109 /* Cache flush command */
 110 #define VIRTIO_BLK_T_FLUSH      4
 111
 112 /* Get device ID command */
 113 #define VIRTIO_BLK_T_GET_ID    8
 114
 115 #ifndef VIRTIO_BLK_NO_LEGACY
 116 /* Barrier before this op. */
 117 #define VIRTIO_BLK_T_BARRIER    0x80000000
 118 #endif /* !VIRTIO_BLK_NO_LEGACY */
 119
 120 /*
 121  * This comes first in the read scatter-gather list.
 122  * For legacy virtio, if VIRTIO_F_ANY_LAYOUT is not negotiated,
 123  * this is the first element of the read scatter-gather list.
 124  */
 125 struct virtio_blk_outhdr {
 126         /* VIRTIO_BLK_T* */
 127         __virtio32 type;
 128         /* io priority. */
 129         __virtio32 ioprio;
 130         /* Sector (ie. 512 byte offset) */
 131         __virtio64 sector;
 132 };
 133
 134 #ifndef VIRTIO_BLK_NO_LEGACY
 135 struct virtio_scsi_inhdr {
 136         __virtio32 errors;
 137         __virtio32 data_len;
 138         __virtio32 sense_len;
 139         __virtio32 residual;
 140 };
 141 #endif /* !VIRTIO_BLK_NO_LEGACY */
 142
 143 /* And this is the final byte of the write scatter-gather list. */
 144 #define VIRTIO_BLK_S_OK         0
 145 #define VIRTIO_BLK_S_IOERR      1
 146 #define VIRTIO_BLK_S_UNSUPP     2
 147 #endif /* _LINUX_VIRTIO_BLK_H */