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_WCE	9	/* Writeback mode enabled after reset */
47 #define VIRTIO_BLK_F_CONFIG_WCE	11	/* Writeback mode available in config */
48 /* Old (deprecated) name for VIRTIO_BLK_F_WCE. */
49 #define VIRTIO_BLK_F_FLUSH VIRTIO_BLK_F_WCE
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 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 /* This is the first element of the read scatter-gather list. */
121 struct virtio_blk_outhdr {
122 	/* VIRTIO_BLK_T* */
123 	__virtio32 type;
124 	/* io priority. */
125 	__virtio32 ioprio;
126 	/* Sector (ie. 512 byte offset) */
127 	__virtio64 sector;
128 };
129 
130 #ifndef VIRTIO_BLK_NO_LEGACY
131 struct virtio_scsi_inhdr {
132 	__virtio32 errors;
133 	__virtio32 data_len;
134 	__virtio32 sense_len;
135 	__virtio32 residual;
136 };
137 #endif /* !VIRTIO_BLK_NO_LEGACY */
138 
139 /* And this is the final byte of the write scatter-gather list. */
140 #define VIRTIO_BLK_S_OK		0
141 #define VIRTIO_BLK_S_IOERR	1
142 #define VIRTIO_BLK_S_UNSUPP	2
143 #endif /* _LINUX_VIRTIO_BLK_H */
144