1 /* SPDX-License-Identifier: BSD-3-Clause */ 2 /* 3 * Copyright (C) 2018, Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi> 4 * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com> 5 * 6 * From Linux kernel include/uapi/linux/virtio_blk.h 7 */ 8 9 #ifndef _LINUX_VIRTIO_BLK_H 10 #define _LINUX_VIRTIO_BLK_H 11 12 /* Feature bits */ 13 #define VIRTIO_BLK_F_SIZE_MAX 1 /* Indicates maximum segment size */ 14 #define VIRTIO_BLK_F_SEG_MAX 2 /* Indicates maximum # of segments */ 15 #define VIRTIO_BLK_F_GEOMETRY 4 /* Legacy geometry available */ 16 #define VIRTIO_BLK_F_RO 5 /* Disk is read-only */ 17 #define VIRTIO_BLK_F_BLK_SIZE 6 /* Block size of disk is available */ 18 #define VIRTIO_BLK_F_TOPOLOGY 10 /* Topology information is available */ 19 #define VIRTIO_BLK_F_MQ 12 /* Support more than one vq */ 20 #define VIRTIO_BLK_F_DISCARD 13 /* Discard is supported */ 21 #define VIRTIO_BLK_F_WRITE_ZEROES 14 /* Write zeroes is supported */ 22 23 /* Legacy feature bits */ 24 #ifndef VIRTIO_BLK_NO_LEGACY 25 #define VIRTIO_BLK_F_BARRIER 0 /* Does host support barriers? */ 26 #define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */ 27 #define VIRTIO_BLK_F_FLUSH 9 /* Flush command supported */ 28 #define VIRTIO_BLK_F_CONFIG_WCE 11 /* Writeback mode available in config */ 29 #ifndef __KERNEL__ 30 /* Old (deprecated) name for VIRTIO_BLK_F_FLUSH */ 31 #define VIRTIO_BLK_F_WCE VIRTIO_BLK_F_FLUSH 32 #endif 33 #endif /* !VIRTIO_BLK_NO_LEGACY */ 34 35 #define VIRTIO_BLK_ID_BYTES 20 /* ID string length */ 36 37 struct __packed virtio_blk_config { 38 /* The capacity (in 512-byte sectors) */ 39 __u64 capacity; 40 /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */ 41 __u32 size_max; 42 /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */ 43 __u32 seg_max; 44 /* geometry of the device (if VIRTIO_BLK_F_GEOMETRY) */ 45 struct virtio_blk_geometry { 46 __u16 cylinders; 47 __u8 heads; 48 __u8 sectors; 49 } geometry; 50 51 /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */ 52 __u32 blk_size; 53 54 /* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY */ 55 /* exponent for physical block per logical block */ 56 __u8 physical_block_exp; 57 /* alignment offset in logical blocks */ 58 __u8 alignment_offset; 59 /* minimum I/O size without performance penalty in logical blocks */ 60 __u16 min_io_size; 61 /* optimal sustained I/O size in logical blocks */ 62 __u32 opt_io_size; 63 64 /* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */ 65 __u8 wce; 66 __u8 unused; 67 68 /* number of vqs, only available when VIRTIO_BLK_F_MQ is set */ 69 __u16 num_queues; 70 71 /* the next 3 entries are guarded by VIRTIO_BLK_F_DISCARD */ 72 /* 73 * The maximum discard sectors (in 512-byte sectors) for 74 * one segment. 75 */ 76 __u32 max_discard_sectors; 77 /* 78 * The maximum number of discard segments in a 79 * discard command. 80 */ 81 __u32 max_discard_seg; 82 /* Discard commands must be aligned to this number of sectors. */ 83 __u32 discard_sector_alignment; 84 85 /* the next 3 entries are guarded by VIRTIO_BLK_F_WRITE_ZEROES */ 86 /* 87 * The maximum number of write zeroes sectors (in 512-byte sectors) in 88 * one segment. 89 */ 90 __u32 max_write_zeroes_sectors; 91 /* 92 * The maximum number of segments in a write zeroes 93 * command. 94 */ 95 __u32 max_write_zeroes_seg; 96 /* 97 * Set if a VIRTIO_BLK_T_WRITE_ZEROES request may result in the 98 * deallocation of one or more of the sectors. 99 */ 100 __u8 write_zeroes_may_unmap; 101 102 __u8 unused1[3]; 103 }; 104 105 /* 106 * Command types 107 * 108 * Usage is a bit tricky as some bits are used as flags and some are not. 109 * 110 * Rules: 111 * VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or 112 * VIRTIO_BLK_T_BARRIER. VIRTIO_BLK_T_FLUSH is a command of its own 113 * and may not be combined with any of the other flags. 114 */ 115 116 /* These two define direction */ 117 #define VIRTIO_BLK_T_IN 0 118 #define VIRTIO_BLK_T_OUT 1 119 120 #ifndef VIRTIO_BLK_NO_LEGACY 121 /* This bit says it's a scsi command, not an actual read or write */ 122 #define VIRTIO_BLK_T_SCSI_CMD 2 123 #endif /* VIRTIO_BLK_NO_LEGACY */ 124 125 /* Cache flush command */ 126 #define VIRTIO_BLK_T_FLUSH 4 127 128 /* Get device ID command */ 129 #define VIRTIO_BLK_T_GET_ID 8 130 131 /* Write zeroes command */ 132 #define VIRTIO_BLK_T_WRITE_ZEROES 13 133 134 #ifndef VIRTIO_BLK_NO_LEGACY 135 /* Barrier before this op */ 136 #define VIRTIO_BLK_T_BARRIER 0x80000000 137 #endif /* !VIRTIO_BLK_NO_LEGACY */ 138 139 /* 140 * This comes first in the read scatter-gather list. 141 * For legacy virtio, if VIRTIO_F_ANY_LAYOUT is not negotiated, 142 * this is the first element of the read scatter-gather list. 143 */ 144 struct virtio_blk_outhdr { 145 /* VIRTIO_BLK_T* */ 146 __virtio32 type; 147 /* io priority */ 148 __virtio32 ioprio; 149 /* Sector (ie. 512 byte offset) */ 150 __virtio64 sector; 151 }; 152 153 struct virtio_blk_discard_write_zeroes { 154 /* discard/write zeroes start sector */ 155 __virtio64 sector; 156 /* number of discard/write zeroes sectors */ 157 __virtio32 num_sectors; 158 /* flags for this range */ 159 __virtio32 flags; 160 }; 161 162 #ifndef VIRTIO_BLK_NO_LEGACY 163 struct virtio_scsi_inhdr { 164 __virtio32 errors; 165 __virtio32 data_len; 166 __virtio32 sense_len; 167 __virtio32 residual; 168 }; 169 #endif /* !VIRTIO_BLK_NO_LEGACY */ 170 171 /* And this is the final byte of the write scatter-gather list */ 172 #define VIRTIO_BLK_S_OK 0 173 #define VIRTIO_BLK_S_IOERR 1 174 #define VIRTIO_BLK_S_UNSUPP 2 175 176 #endif /* _LINUX_VIRTIO_BLK_H */ 177