virtio_blk.h 5.2 KB

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  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. /* Feature bits */
  33. #define VIRTIO_BLK_F_SIZE_MAX 1 /* Indicates maximum segment size */
  34. #define VIRTIO_BLK_F_SEG_MAX 2 /* Indicates maximum # of segments */
  35. #define VIRTIO_BLK_F_GEOMETRY 4 /* Legacy geometry available */
  36. #define VIRTIO_BLK_F_RO 5 /* Disk is read-only */
  37. #define VIRTIO_BLK_F_BLK_SIZE 6 /* Block size of disk is available*/
  38. #define VIRTIO_BLK_F_TOPOLOGY 10 /* Topology information is available */
  39. #define VIRTIO_BLK_F_MQ 12 /* support more than one vq */
  40. /* Legacy feature bits */
  41. #ifndef VIRTIO_BLK_NO_LEGACY
  42. #define VIRTIO_BLK_F_BARRIER 0 /* Does host support barriers? */
  43. #define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */
  44. #define VIRTIO_BLK_F_WCE 9 /* Writeback mode enabled after reset */
  45. #define VIRTIO_BLK_F_CONFIG_WCE 11 /* Writeback mode available in config */
  46. /* Old (deprecated) name for VIRTIO_BLK_F_WCE. */
  47. #define VIRTIO_BLK_F_FLUSH VIRTIO_BLK_F_WCE
  48. #endif /* !VIRTIO_BLK_NO_LEGACY */
  49. #define VIRTIO_BLK_ID_BYTES 20 /* ID string length */
  50. struct virtio_blk_config {
  51. /* The capacity (in 512-byte sectors). */
  52. __u64 capacity;
  53. /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */
  54. __u32 size_max;
  55. /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */
  56. __u32 seg_max;
  57. /* geometry of the device (if VIRTIO_BLK_F_GEOMETRY) */
  58. struct virtio_blk_geometry {
  59. __u16 cylinders;
  60. __u8 heads;
  61. __u8 sectors;
  62. } geometry;
  63. /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */
  64. __u32 blk_size;
  65. /* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY */
  66. /* exponent for physical block per logical block. */
  67. __u8 physical_block_exp;
  68. /* alignment offset in logical blocks. */
  69. __u8 alignment_offset;
  70. /* minimum I/O size without performance penalty in logical blocks. */
  71. __u16 min_io_size;
  72. /* optimal sustained I/O size in logical blocks. */
  73. __u32 opt_io_size;
  74. /* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */
  75. __u8 wce;
  76. __u8 unused;
  77. /* number of vqs, only available when VIRTIO_BLK_F_MQ is set */
  78. __u16 num_queues;
  79. } __attribute__((packed));
  80. /*
  81. * Command types
  82. *
  83. * Usage is a bit tricky as some bits are used as flags and some are not.
  84. *
  85. * Rules:
  86. * VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
  87. * VIRTIO_BLK_T_BARRIER. VIRTIO_BLK_T_FLUSH is a command of its own
  88. * and may not be combined with any of the other flags.
  89. */
  90. /* These two define direction. */
  91. #define VIRTIO_BLK_T_IN 0
  92. #define VIRTIO_BLK_T_OUT 1
  93. #ifndef VIRTIO_BLK_NO_LEGACY
  94. /* This bit says it's a scsi command, not an actual read or write. */
  95. #define VIRTIO_BLK_T_SCSI_CMD 2
  96. #endif /* VIRTIO_BLK_NO_LEGACY */
  97. /* Cache flush command */
  98. #define VIRTIO_BLK_T_FLUSH 4
  99. /* Get device ID command */
  100. #define VIRTIO_BLK_T_GET_ID 8
  101. #ifndef VIRTIO_BLK_NO_LEGACY
  102. /* Barrier before this op. */
  103. #define VIRTIO_BLK_T_BARRIER 0x80000000
  104. #endif /* !VIRTIO_BLK_NO_LEGACY */
  105. /*
  106. * This comes first in the read scatter-gather list.
  107. * For legacy virtio, if VIRTIO_F_ANY_LAYOUT is not negotiated,
  108. * this is the first element of the read scatter-gather list.
  109. */
  110. struct virtio_blk_outhdr {
  111. /* VIRTIO_BLK_T* */
  112. __virtio32 type;
  113. /* io priority. */
  114. __virtio32 ioprio;
  115. /* Sector (ie. 512 byte offset) */
  116. __virtio64 sector;
  117. };
  118. #ifndef VIRTIO_BLK_NO_LEGACY
  119. struct virtio_scsi_inhdr {
  120. __virtio32 errors;
  121. __virtio32 data_len;
  122. __virtio32 sense_len;
  123. __virtio32 residual;
  124. };
  125. #endif /* !VIRTIO_BLK_NO_LEGACY */
  126. /* And this is the final byte of the write scatter-gather list. */
  127. #define VIRTIO_BLK_S_OK 0
  128. #define VIRTIO_BLK_S_IOERR 1
  129. #define VIRTIO_BLK_S_UNSUPP 2
  130. #endif /* _LINUX_VIRTIO_BLK_H */