| 1 | /* $NetBSD: blkif.h,v 1.7 2016/07/07 06:55:40 msaitoh Exp $ */ |
| 2 | /****************************************************************************** |
| 3 | * blkif.h |
| 4 | * |
| 5 | * Unified block-device I/O interface for Xen guest OSes. |
| 6 | * |
| 7 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
| 8 | * of this software and associated documentation files (the "Software"), to |
| 9 | * deal in the Software without restriction, including without limitation the |
| 10 | * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or |
| 11 | * sell copies of the Software, and to permit persons to whom the Software is |
| 12 | * furnished to do so, subject to the following conditions: |
| 13 | * |
| 14 | * The above copyright notice and this permission notice shall be included in |
| 15 | * all copies or substantial portions of the Software. |
| 16 | * |
| 17 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 18 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 19 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| 20 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| 21 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| 22 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
| 23 | * DEALINGS IN THE SOFTWARE. |
| 24 | * |
| 25 | * Copyright (c) 2003-2004, Keir Fraser |
| 26 | */ |
| 27 | |
| 28 | #ifndef __XEN_PUBLIC_IO_BLKIF_H__ |
| 29 | #define __XEN_PUBLIC_IO_BLKIF_H__ |
| 30 | |
| 31 | #include "ring.h" |
| 32 | #include "../grant_table.h" |
| 33 | |
| 34 | /* |
| 35 | * Front->back notifications: When enqueuing a new request, sending a |
| 36 | * notification can be made conditional on req_event (i.e., the generic |
| 37 | * hold-off mechanism provided by the ring macros). Backends must set |
| 38 | * req_event appropriately (e.g., using RING_FINAL_CHECK_FOR_REQUESTS()). |
| 39 | * |
| 40 | * Back->front notifications: When enqueuing a new response, sending a |
| 41 | * notification can be made conditional on rsp_event (i.e., the generic |
| 42 | * hold-off mechanism provided by the ring macros). Frontends must set |
| 43 | * rsp_event appropriately (e.g., using RING_FINAL_CHECK_FOR_RESPONSES()). |
| 44 | */ |
| 45 | |
| 46 | #ifndef blkif_vdev_t |
| 47 | #define blkif_vdev_t uint16_t |
| 48 | #endif |
| 49 | #define blkif_sector_t uint64_t |
| 50 | |
| 51 | /* |
| 52 | * REQUEST CODES. |
| 53 | */ |
| 54 | #define BLKIF_OP_READ 0 |
| 55 | #define BLKIF_OP_WRITE 1 |
| 56 | /* |
| 57 | * Recognised only if "feature-barrier" is present in backend xenbus info. |
| 58 | * The "feature-barrier" node contains a boolean indicating whether barrier |
| 59 | * requests are likely to succeed or fail. Either way, a barrier request |
| 60 | * may fail at any time with BLKIF_RSP_EOPNOTSUPP if it is unsupported by |
| 61 | * the underlying block-device hardware. The boolean simply indicates whether |
| 62 | * or not it is worthwhile for the frontend to attempt barrier requests. |
| 63 | * If a backend does not recognise BLKIF_OP_WRITE_BARRIER, it should *not* |
| 64 | * create the "feature-barrier" node! |
| 65 | */ |
| 66 | #define BLKIF_OP_WRITE_BARRIER 2 |
| 67 | /* |
| 68 | * Recognised if "feature-flush-cache" is present in backend xenbus |
| 69 | * info. A flush will ask the underlying storage hardware to flush its |
| 70 | * non-volatile caches as appropriate. The "feature-flush-cache" node |
| 71 | * contains a boolean indicating whether flush requests are likely to |
| 72 | * succeed or fail. Either way, a flush request may fail at any time |
| 73 | * with BLKIF_RSP_EOPNOTSUPP if it is unsupported by the underlying |
| 74 | * block-device hardware. The boolean simply indicates whether or not it |
| 75 | * is worthwhile for the frontend to attempt flushes. If a backend does |
| 76 | * not recognise BLKIF_OP_WRITE_FLUSH_CACHE, it should *not* create the |
| 77 | * "feature-flush-cache" node! |
| 78 | */ |
| 79 | #define BLKIF_OP_FLUSH_DISKCACHE 3 |
| 80 | |
| 81 | /* |
| 82 | * Maximum scatter/gather segments per request. |
| 83 | * This is carefully chosen so that sizeof(blkif_ring_t) <= PAGE_SIZE. |
| 84 | * NB. This could be 12 if the ring indexes weren't stored in the same page. |
| 85 | */ |
| 86 | #define BLKIF_MAX_SEGMENTS_PER_REQUEST 11 |
| 87 | |
| 88 | struct blkif_request_segment { |
| 89 | grant_ref_t gref; /* reference to I/O buffer frame */ |
| 90 | /* @first_sect: first sector in frame to transfer (inclusive). */ |
| 91 | /* @last_sect: last sector in frame to transfer (inclusive). */ |
| 92 | uint8_t first_sect, last_sect; |
| 93 | }; |
| 94 | |
| 95 | /* native-type requests/responses (always used in frontends ) */ |
| 96 | |
| 97 | struct blkif_request { |
| 98 | uint8_t operation; /* BLKIF_OP_??? */ |
| 99 | uint8_t nr_segments; /* number of segments */ |
| 100 | blkif_vdev_t handle; /* only for read/write requests */ |
| 101 | uint64_t id; /* private guest value, echoed in resp */ |
| 102 | blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ |
| 103 | struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
| 104 | }; |
| 105 | typedef struct blkif_request blkif_request_t; |
| 106 | |
| 107 | struct blkif_response { |
| 108 | uint64_t id; /* copied from request */ |
| 109 | uint8_t operation; /* copied from request */ |
| 110 | int16_t status; /* BLKIF_RSP_??? */ |
| 111 | }; |
| 112 | typedef struct blkif_response blkif_response_t; |
| 113 | |
| 114 | /* i386 requests/responses */ |
| 115 | struct blkif_x86_32_request { |
| 116 | uint8_t operation; /* BLKIF_OP_??? */ |
| 117 | uint8_t nr_segments; /* number of segments */ |
| 118 | blkif_vdev_t handle; /* only for read/write requests */ |
| 119 | uint64_t id; /* private guest value, echoed in resp */ |
| 120 | blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ |
| 121 | struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
| 122 | } __packed; |
| 123 | typedef struct blkif_x86_32_request blkif_x86_32_request_t; |
| 124 | |
| 125 | struct blkif_x86_32_response { |
| 126 | uint64_t id; /* copied from request */ |
| 127 | uint8_t operation; /* copied from request */ |
| 128 | uint8_t _pad; |
| 129 | int16_t status; /* BLKIF_RSP_??? */ |
| 130 | } __packed; |
| 131 | typedef struct blkif_x86_32_response blkif_x86_32_response_t; |
| 132 | |
| 133 | /* amd64-type requests/responses (always used in frontends ) */ |
| 134 | |
| 135 | struct blkif_x86_64_request { |
| 136 | uint8_t operation; /* BLKIF_OP_??? */ |
| 137 | uint8_t nr_segments; /* number of segments */ |
| 138 | blkif_vdev_t handle; /* only for read/write requests */ |
| 139 | uint64_t __attribute__((__aligned__(8))) id;/* private guest value, echoed in resp */ |
| 140 | blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ |
| 141 | struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
| 142 | }; |
| 143 | typedef struct blkif_x86_64_request blkif_x86_64_request_t; |
| 144 | |
| 145 | struct blkif_x86_64_response { |
| 146 | uint64_t __attribute__((__aligned__(8))) id; /* copied from request */ |
| 147 | uint8_t operation; /* copied from request */ |
| 148 | int16_t status; /* BLKIF_RSP_??? */ |
| 149 | }; |
| 150 | typedef struct blkif_x86_64_response blkif_x86_64_response_t; |
| 151 | |
| 152 | /* |
| 153 | * STATUS RETURN CODES. |
| 154 | */ |
| 155 | /* Operation not supported (only happens on barrier writes). */ |
| 156 | #define BLKIF_RSP_EOPNOTSUPP -2 |
| 157 | /* Operation failed for some unspecified reason (-EIO). */ |
| 158 | #define BLKIF_RSP_ERROR -1 |
| 159 | /* Operation completed successfully. */ |
| 160 | #define BLKIF_RSP_OKAY 0 |
| 161 | |
| 162 | /* |
| 163 | * Generate blkif ring structures and types. |
| 164 | */ |
| 165 | |
| 166 | DEFINE_RING_TYPES(blkif, struct blkif_request, struct blkif_response); |
| 167 | DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request, struct blkif_x86_32_response); |
| 168 | DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request, struct blkif_x86_64_response); |
| 169 | |
| 170 | union blkif_back_ring_proto { |
| 171 | blkif_back_ring_t ring_n; /* native/common members */ |
| 172 | blkif_x86_32_back_ring_t ring_32; |
| 173 | blkif_x86_64_back_ring_t ring_64; |
| 174 | }; |
| 175 | typedef union blkif_back_ring_proto blkif_back_ring_proto_t; |
| 176 | |
| 177 | #define VDISK_CDROM 0x1 |
| 178 | #define VDISK_REMOVABLE 0x2 |
| 179 | #define VDISK_READONLY 0x4 |
| 180 | |
| 181 | #endif /* __XEN_PUBLIC_IO_BLKIF_H__ */ |
| 182 | |
| 183 | /* |
| 184 | * Local variables: |
| 185 | * mode: C |
| 186 | * c-set-style: "BSD" |
| 187 | * c-basic-offset: 4 |
| 188 | * tab-width: 4 |
| 189 | * indent-tabs-mode: nil |
| 190 | * End: |
| 191 | */ |
| 192 | |