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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 | /* * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation; or, when distributed * separately from the Linux kernel or incorporated into other * software packages, subject to the following license: * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this source file (the "Software"), to deal in the Software without * restriction, including without limitation the rights to use, copy, modify, * merge, publish, distribute, sublicense, and/or sell copies of the Software, * and to permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS * IN THE SOFTWARE. */ #ifndef __XEN_BLKIF__BACKEND__COMMON_H__ #define __XEN_BLKIF__BACKEND__COMMON_H__ #include <linux/module.h> #include <linux/interrupt.h> #include <linux/slab.h> #include <linux/blkdev.h> #include <linux/vmalloc.h> #include <linux/wait.h> #include <linux/io.h> #include <linux/rbtree.h> #include <asm/setup.h> #include <asm/hypervisor.h> #include <xen/grant_table.h> #include <xen/page.h> #include <xen/xenbus.h> #include <xen/interface/io/ring.h> #include <xen/interface/io/blkif.h> #include <xen/interface/io/protocols.h> extern unsigned int xen_blkif_max_ring_order; extern unsigned int xenblk_max_queues; /* * This is the maximum number of segments that would be allowed in indirect * requests. This value will also be passed to the frontend. */ #define MAX_INDIRECT_SEGMENTS 256 /* * Xen use 4K pages. The guest may use different page size (4K or 64K) * Number of Xen pages per segment */ #define XEN_PAGES_PER_SEGMENT (PAGE_SIZE / XEN_PAGE_SIZE) #define XEN_PAGES_PER_INDIRECT_FRAME \ (XEN_PAGE_SIZE/sizeof(struct blkif_request_segment)) #define SEGS_PER_INDIRECT_FRAME \ (XEN_PAGES_PER_INDIRECT_FRAME / XEN_PAGES_PER_SEGMENT) #define MAX_INDIRECT_PAGES \ ((MAX_INDIRECT_SEGMENTS + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME) #define INDIRECT_PAGES(_segs) DIV_ROUND_UP(_segs, XEN_PAGES_PER_INDIRECT_FRAME) /* Not a real protocol. Used to generate ring structs which contain * the elements common to all protocols only. This way we get a * compiler-checkable way to use common struct elements, so we can * avoid using switch(protocol) in a number of places. */ struct blkif_common_request { char dummy; }; /* i386 protocol version */ struct blkif_x86_32_request_rw { uint8_t nr_segments; /* number of segments */ blkif_vdev_t handle; /* only for read/write requests */ uint64_t id; /* private guest value, echoed in resp */ blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; } __attribute__((__packed__)); struct blkif_x86_32_request_discard { uint8_t flag; /* BLKIF_DISCARD_SECURE or zero */ blkif_vdev_t _pad1; /* was "handle" for read/write requests */ uint64_t id; /* private guest value, echoed in resp */ blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ uint64_t nr_sectors; } __attribute__((__packed__)); struct blkif_x86_32_request_other { uint8_t _pad1; blkif_vdev_t _pad2; uint64_t id; /* private guest value, echoed in resp */ } __attribute__((__packed__)); struct blkif_x86_32_request_indirect { uint8_t indirect_op; uint16_t nr_segments; uint64_t id; blkif_sector_t sector_number; blkif_vdev_t handle; uint16_t _pad1; grant_ref_t indirect_grefs[BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST]; /* * The maximum number of indirect segments (and pages) that will * be used is determined by MAX_INDIRECT_SEGMENTS, this value * is also exported to the guest (via xenstore * feature-max-indirect-segments entry), so the frontend knows how * many indirect segments the backend supports. */ uint64_t _pad2; /* make it 64 byte aligned */ } __attribute__((__packed__)); struct blkif_x86_32_request { uint8_t operation; /* BLKIF_OP_??? */ union { struct blkif_x86_32_request_rw rw; struct blkif_x86_32_request_discard discard; struct blkif_x86_32_request_other other; struct blkif_x86_32_request_indirect indirect; } u; } __attribute__((__packed__)); /* x86_64 protocol version */ struct blkif_x86_64_request_rw { uint8_t nr_segments; /* number of segments */ blkif_vdev_t handle; /* only for read/write requests */ uint32_t _pad1; /* offsetof(blkif_reqest..,u.rw.id)==8 */ uint64_t id; blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; } __attribute__((__packed__)); struct blkif_x86_64_request_discard { uint8_t flag; /* BLKIF_DISCARD_SECURE or zero */ blkif_vdev_t _pad1; /* was "handle" for read/write requests */ uint32_t _pad2; /* offsetof(blkif_..,u.discard.id)==8 */ uint64_t id; blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ uint64_t nr_sectors; } __attribute__((__packed__)); struct blkif_x86_64_request_other { uint8_t _pad1; blkif_vdev_t _pad2; uint32_t _pad3; /* offsetof(blkif_..,u.discard.id)==8 */ uint64_t id; /* private guest value, echoed in resp */ } __attribute__((__packed__)); struct blkif_x86_64_request_indirect { uint8_t indirect_op; uint16_t nr_segments; uint32_t _pad1; /* offsetof(blkif_..,u.indirect.id)==8 */ uint64_t id; blkif_sector_t sector_number; blkif_vdev_t handle; uint16_t _pad2; grant_ref_t indirect_grefs[BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST]; /* * The maximum number of indirect segments (and pages) that will * be used is determined by MAX_INDIRECT_SEGMENTS, this value * is also exported to the guest (via xenstore * feature-max-indirect-segments entry), so the frontend knows how * many indirect segments the backend supports. */ uint32_t _pad3; /* make it 64 byte aligned */ } __attribute__((__packed__)); struct blkif_x86_64_request { uint8_t operation; /* BLKIF_OP_??? */ union { struct blkif_x86_64_request_rw rw; struct blkif_x86_64_request_discard discard; struct blkif_x86_64_request_other other; struct blkif_x86_64_request_indirect indirect; } u; } __attribute__((__packed__)); DEFINE_RING_TYPES(blkif_common, struct blkif_common_request, struct blkif_response); DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request, struct blkif_response __packed); DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request, struct blkif_response); union blkif_back_rings { struct blkif_back_ring native; struct blkif_common_back_ring common; struct blkif_x86_32_back_ring x86_32; struct blkif_x86_64_back_ring x86_64; }; enum blkif_protocol { BLKIF_PROTOCOL_NATIVE = 1, BLKIF_PROTOCOL_X86_32 = 2, BLKIF_PROTOCOL_X86_64 = 3, }; /* * Default protocol if the frontend doesn't specify one. */ #ifdef CONFIG_X86 # define BLKIF_PROTOCOL_DEFAULT BLKIF_PROTOCOL_X86_32 #else # define BLKIF_PROTOCOL_DEFAULT BLKIF_PROTOCOL_NATIVE #endif struct xen_vbd { /* What the domain refers to this vbd as. */ blkif_vdev_t handle; /* Non-zero -> read-only */ unsigned char readonly; /* VDISK_xxx */ unsigned char type; /* phys device that this vbd maps to. */ u32 pdevice; struct block_device *bdev; /* Cached size parameter. */ sector_t size; unsigned int flush_support:1; unsigned int discard_secure:1; /* Connect-time cached feature_persistent parameter value */ unsigned int feature_gnt_persistent_parm:1; /* Persistent grants feature negotiation result */ unsigned int feature_gnt_persistent:1; unsigned int overflow_max_grants:1; }; struct backend_info; /* Number of requests that we can fit in a ring */ #define XEN_BLKIF_REQS_PER_PAGE 32 struct persistent_gnt { struct page *page; grant_ref_t gnt; grant_handle_t handle; unsigned long last_used; bool active; struct rb_node node; struct list_head remove_node; }; /* Per-ring information. */ struct xen_blkif_ring { /* Physical parameters of the comms window. */ unsigned int irq; union blkif_back_rings blk_rings; void *blk_ring; /* Private fields. */ spinlock_t blk_ring_lock; wait_queue_head_t wq; atomic_t inflight; bool active; /* One thread per blkif ring. */ struct task_struct *xenblkd; unsigned int waiting_reqs; /* List of all 'pending_req' available */ struct list_head pending_free; /* And its spinlock. */ spinlock_t pending_free_lock; wait_queue_head_t pending_free_wq; /* Tree to store persistent grants. */ struct rb_root persistent_gnts; unsigned int persistent_gnt_c; atomic_t persistent_gnt_in_use; unsigned long next_lru; /* Statistics. */ unsigned long st_print; unsigned long long st_rd_req; unsigned long long st_wr_req; unsigned long long st_oo_req; unsigned long long st_f_req; unsigned long long st_ds_req; unsigned long long st_rd_sect; unsigned long long st_wr_sect; /* Used by the kworker that offload work from the persistent purge. */ struct list_head persistent_purge_list; struct work_struct persistent_purge_work; /* Buffer of free pages to map grant refs. */ struct gnttab_page_cache free_pages; struct work_struct free_work; /* Thread shutdown wait queue. */ wait_queue_head_t shutdown_wq; struct xen_blkif *blkif; }; struct xen_blkif { /* Unique identifier for this interface. */ domid_t domid; unsigned int handle; /* Comms information. */ enum blkif_protocol blk_protocol; /* The VBD attached to this interface. */ struct xen_vbd vbd; /* Back pointer to the backend_info. */ struct backend_info *be; atomic_t refcnt; /* for barrier (drain) requests */ struct completion drain_complete; atomic_t drain; struct work_struct free_work; unsigned int nr_ring_pages; bool multi_ref; /* All rings for this device. */ struct xen_blkif_ring *rings; unsigned int nr_rings; unsigned long buffer_squeeze_end; }; struct seg_buf { unsigned long offset; unsigned int nsec; }; struct grant_page { struct page *page; struct persistent_gnt *persistent_gnt; grant_handle_t handle; grant_ref_t gref; }; /* * Each outstanding request that we've passed to the lower device layers has a * 'pending_req' allocated to it. Each buffer_head that completes decrements * the pendcnt towards zero. When it hits zero, the specified domain has a * response queued for it, with the saved 'id' passed back. */ struct pending_req { struct xen_blkif_ring *ring; u64 id; int nr_segs; atomic_t pendcnt; unsigned short operation; int status; struct list_head free_list; struct grant_page *segments[MAX_INDIRECT_SEGMENTS]; /* Indirect descriptors */ struct grant_page *indirect_pages[MAX_INDIRECT_PAGES]; struct seg_buf seg[MAX_INDIRECT_SEGMENTS]; struct bio *biolist[MAX_INDIRECT_SEGMENTS]; struct gnttab_unmap_grant_ref unmap[MAX_INDIRECT_SEGMENTS]; struct page *unmap_pages[MAX_INDIRECT_SEGMENTS]; struct gntab_unmap_queue_data gnttab_unmap_data; }; #define vbd_sz(_v) bdev_nr_sectors((_v)->bdev) #define xen_blkif_get(_b) (atomic_inc(&(_b)->refcnt)) #define xen_blkif_put(_b) \ do { \ if (atomic_dec_and_test(&(_b)->refcnt)) \ schedule_work(&(_b)->free_work);\ } while (0) struct phys_req { unsigned short dev; blkif_sector_t nr_sects; struct block_device *bdev; blkif_sector_t sector_number; }; int xen_blkif_interface_init(void); void xen_blkif_interface_fini(void); int xen_blkif_xenbus_init(void); void xen_blkif_xenbus_fini(void); irqreturn_t xen_blkif_be_int(int irq, void *dev_id); int xen_blkif_schedule(void *arg); void xen_blkbk_free_caches(struct xen_blkif_ring *ring); int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt, struct backend_info *be, int state); int xen_blkbk_barrier(struct xenbus_transaction xbt, struct backend_info *be, int state); struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be); void xen_blkbk_unmap_purged_grants(struct work_struct *work); #endif /* __XEN_BLKIF__BACKEND__COMMON_H__ */ |