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 32 /* Feature bits */ 33 #define VIRTIO_BLK_F_BARRIER 0 /* Does host support barriers? */ 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_SCSI 7 /* Supports scsi command passthru */ 40 #define VIRTIO_BLK_F_WCE 9 /* Writeback mode enabled after reset */ 41 #define VIRTIO_BLK_F_TOPOLOGY 10 /* Topology information is available */ 42 #define VIRTIO_BLK_F_CONFIG_WCE 11 /* Writeback mode available in config */ 43 44 #ifndef __KERNEL__ 45 /* Old (deprecated) name for VIRTIO_BLK_F_WCE. */ 46 #define VIRTIO_BLK_F_FLUSH VIRTIO_BLK_F_WCE 47 #endif 48 49 #define VIRTIO_BLK_ID_BYTES 20 /* ID string length */ 50 51 struct virtio_blk_config { 52 /* The capacity (in 512-byte sectors). */ 53 __u64 capacity; 54 /* The maximum segment size (if VIRTIO_BLK_F_SIZE_MAX) */ 55 __u32 size_max; 56 /* The maximum number of segments (if VIRTIO_BLK_F_SEG_MAX) */ 57 __u32 seg_max; 58 /* geometry the device (if VIRTIO_BLK_F_GEOMETRY) */ 59 struct virtio_blk_geometry { 60 __u16 cylinders; 61 __u8 heads; 62 __u8 sectors; 63 } geometry; 64 65 /* block size of device (if VIRTIO_BLK_F_BLK_SIZE) */ 66 __u32 blk_size; 67 68 /* the next 4 entries are guarded by VIRTIO_BLK_F_TOPOLOGY */ 69 /* exponent for physical block per logical block. */ 70 __u8 physical_block_exp; 71 /* alignment offset in logical blocks. */ 72 __u8 alignment_offset; 73 /* minimum I/O size without performance penalty in logical blocks. */ 74 __u16 min_io_size; 75 /* optimal sustained I/O size in logical blocks. */ 76 __u32 opt_io_size; 77 78 /* writeback mode (if VIRTIO_BLK_F_CONFIG_WCE) */ 79 __u8 wce; 80 } __attribute__((packed)); 81 82 /* 83 * Command types 84 * 85 * Usage is a bit tricky as some bits are used as flags and some are not. 86 * 87 * Rules: 88 * VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or 89 * VIRTIO_BLK_T_BARRIER. VIRTIO_BLK_T_FLUSH is a command of its own 90 * and may not be combined with any of the other flags. 91 */ 92 93 /* These two define direction. */ 94 #define VIRTIO_BLK_T_IN 0 95 #define VIRTIO_BLK_T_OUT 1 96 97 /* This bit says it's a scsi command, not an actual read or write. */ 98 #define VIRTIO_BLK_T_SCSI_CMD 2 99 100 /* Cache flush command */ 101 #define VIRTIO_BLK_T_FLUSH 4 102 103 /* Get device ID command */ 104 #define VIRTIO_BLK_T_GET_ID 8 105 106 /* Barrier before this op. */ 107 #define VIRTIO_BLK_T_BARRIER 0x80000000 108 109 /* This is the first element of the read scatter-gather list. */ 110 struct virtio_blk_outhdr { 111 /* VIRTIO_BLK_T* */ 112 __u32 type; 113 /* io priority. */ 114 __u32 ioprio; 115 /* Sector (ie. 512 byte offset) */ 116 __u64 sector; 117 }; 118 119 struct virtio_scsi_inhdr { 120 __u32 errors; 121 __u32 data_len; 122 __u32 sense_len; 123 __u32 residual; 124 }; 125 126 /* 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 */ 131