Jeremy Fitzhardinge | ad9a861 | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 1 | /****************************************************************************** |
| 2 | * grant_table.c |
| 3 | * |
| 4 | * Granting foreign access to our memory reservation. |
| 5 | * |
| 6 | * Copyright (c) 2005-2006, Christopher Clark |
| 7 | * Copyright (c) 2004-2005, K A Fraser |
| 8 | * |
| 9 | * This program is free software; you can redistribute it and/or |
| 10 | * modify it under the terms of the GNU General Public License version 2 |
| 11 | * as published by the Free Software Foundation; or, when distributed |
| 12 | * separately from the Linux kernel or incorporated into other |
| 13 | * software packages, subject to the following license: |
| 14 | * |
| 15 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
| 16 | * of this source file (the "Software"), to deal in the Software without |
| 17 | * restriction, including without limitation the rights to use, copy, modify, |
| 18 | * merge, publish, distribute, sublicense, and/or sell copies of the Software, |
| 19 | * and to permit persons to whom the Software is furnished to do so, subject to |
| 20 | * the following conditions: |
| 21 | * |
| 22 | * The above copyright notice and this permission notice shall be included in |
| 23 | * all copies or substantial portions of the Software. |
| 24 | * |
| 25 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 26 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 27 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| 28 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| 29 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| 30 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS |
| 31 | * IN THE SOFTWARE. |
| 32 | */ |
| 33 | |
| 34 | #include <linux/module.h> |
| 35 | #include <linux/sched.h> |
| 36 | #include <linux/mm.h> |
| 37 | #include <linux/vmalloc.h> |
| 38 | #include <linux/uaccess.h> |
| 39 | |
| 40 | #include <xen/interface/xen.h> |
| 41 | #include <xen/page.h> |
| 42 | #include <xen/grant_table.h> |
| 43 | |
| 44 | #include <asm/pgtable.h> |
| 45 | #include <asm/sync_bitops.h> |
| 46 | |
| 47 | |
| 48 | /* External tools reserve first few grant table entries. */ |
| 49 | #define NR_RESERVED_ENTRIES 8 |
| 50 | #define GNTTAB_LIST_END 0xffffffff |
| 51 | #define GREFS_PER_GRANT_FRAME (PAGE_SIZE / sizeof(struct grant_entry)) |
| 52 | |
| 53 | static grant_ref_t **gnttab_list; |
| 54 | static unsigned int nr_grant_frames; |
| 55 | static unsigned int boot_max_nr_grant_frames; |
| 56 | static int gnttab_free_count; |
| 57 | static grant_ref_t gnttab_free_head; |
| 58 | static DEFINE_SPINLOCK(gnttab_list_lock); |
| 59 | |
| 60 | static struct grant_entry *shared; |
| 61 | |
| 62 | static struct gnttab_free_callback *gnttab_free_callback_list; |
| 63 | |
| 64 | static int gnttab_expand(unsigned int req_entries); |
| 65 | |
| 66 | #define RPP (PAGE_SIZE / sizeof(grant_ref_t)) |
| 67 | |
| 68 | static inline grant_ref_t *__gnttab_entry(grant_ref_t entry) |
| 69 | { |
| 70 | return &gnttab_list[(entry) / RPP][(entry) % RPP]; |
| 71 | } |
| 72 | /* This can be used as an l-value */ |
| 73 | #define gnttab_entry(entry) (*__gnttab_entry(entry)) |
| 74 | |
| 75 | static int get_free_entries(unsigned count) |
| 76 | { |
| 77 | unsigned long flags; |
| 78 | int ref, rc; |
| 79 | grant_ref_t head; |
| 80 | |
| 81 | spin_lock_irqsave(&gnttab_list_lock, flags); |
| 82 | |
| 83 | if ((gnttab_free_count < count) && |
| 84 | ((rc = gnttab_expand(count - gnttab_free_count)) < 0)) { |
| 85 | spin_unlock_irqrestore(&gnttab_list_lock, flags); |
| 86 | return rc; |
| 87 | } |
| 88 | |
| 89 | ref = head = gnttab_free_head; |
| 90 | gnttab_free_count -= count; |
| 91 | while (count-- > 1) |
| 92 | head = gnttab_entry(head); |
| 93 | gnttab_free_head = gnttab_entry(head); |
| 94 | gnttab_entry(head) = GNTTAB_LIST_END; |
| 95 | |
| 96 | spin_unlock_irqrestore(&gnttab_list_lock, flags); |
| 97 | |
| 98 | return ref; |
| 99 | } |
| 100 | |
| 101 | static void do_free_callbacks(void) |
| 102 | { |
| 103 | struct gnttab_free_callback *callback, *next; |
| 104 | |
| 105 | callback = gnttab_free_callback_list; |
| 106 | gnttab_free_callback_list = NULL; |
| 107 | |
| 108 | while (callback != NULL) { |
| 109 | next = callback->next; |
| 110 | if (gnttab_free_count >= callback->count) { |
| 111 | callback->next = NULL; |
| 112 | callback->fn(callback->arg); |
| 113 | } else { |
| 114 | callback->next = gnttab_free_callback_list; |
| 115 | gnttab_free_callback_list = callback; |
| 116 | } |
| 117 | callback = next; |
| 118 | } |
| 119 | } |
| 120 | |
| 121 | static inline void check_free_callbacks(void) |
| 122 | { |
| 123 | if (unlikely(gnttab_free_callback_list)) |
| 124 | do_free_callbacks(); |
| 125 | } |
| 126 | |
| 127 | static void put_free_entry(grant_ref_t ref) |
| 128 | { |
| 129 | unsigned long flags; |
| 130 | spin_lock_irqsave(&gnttab_list_lock, flags); |
| 131 | gnttab_entry(ref) = gnttab_free_head; |
| 132 | gnttab_free_head = ref; |
| 133 | gnttab_free_count++; |
| 134 | check_free_callbacks(); |
| 135 | spin_unlock_irqrestore(&gnttab_list_lock, flags); |
| 136 | } |
| 137 | |
| 138 | static void update_grant_entry(grant_ref_t ref, domid_t domid, |
| 139 | unsigned long frame, unsigned flags) |
| 140 | { |
| 141 | /* |
| 142 | * Introducing a valid entry into the grant table: |
| 143 | * 1. Write ent->domid. |
| 144 | * 2. Write ent->frame: |
| 145 | * GTF_permit_access: Frame to which access is permitted. |
| 146 | * GTF_accept_transfer: Pseudo-phys frame slot being filled by new |
| 147 | * frame, or zero if none. |
| 148 | * 3. Write memory barrier (WMB). |
| 149 | * 4. Write ent->flags, inc. valid type. |
| 150 | */ |
| 151 | shared[ref].frame = frame; |
| 152 | shared[ref].domid = domid; |
| 153 | wmb(); |
| 154 | shared[ref].flags = flags; |
| 155 | } |
| 156 | |
| 157 | /* |
| 158 | * Public grant-issuing interface functions |
| 159 | */ |
| 160 | void gnttab_grant_foreign_access_ref(grant_ref_t ref, domid_t domid, |
| 161 | unsigned long frame, int readonly) |
| 162 | { |
| 163 | update_grant_entry(ref, domid, frame, |
| 164 | GTF_permit_access | (readonly ? GTF_readonly : 0)); |
| 165 | } |
| 166 | EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access_ref); |
| 167 | |
| 168 | int gnttab_grant_foreign_access(domid_t domid, unsigned long frame, |
| 169 | int readonly) |
| 170 | { |
| 171 | int ref; |
| 172 | |
| 173 | ref = get_free_entries(1); |
| 174 | if (unlikely(ref < 0)) |
| 175 | return -ENOSPC; |
| 176 | |
| 177 | gnttab_grant_foreign_access_ref(ref, domid, frame, readonly); |
| 178 | |
| 179 | return ref; |
| 180 | } |
| 181 | EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access); |
| 182 | |
| 183 | int gnttab_query_foreign_access(grant_ref_t ref) |
| 184 | { |
| 185 | u16 nflags; |
| 186 | |
| 187 | nflags = shared[ref].flags; |
| 188 | |
| 189 | return (nflags & (GTF_reading|GTF_writing)); |
| 190 | } |
| 191 | EXPORT_SYMBOL_GPL(gnttab_query_foreign_access); |
| 192 | |
| 193 | int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly) |
| 194 | { |
| 195 | u16 flags, nflags; |
| 196 | |
| 197 | nflags = shared[ref].flags; |
| 198 | do { |
| 199 | flags = nflags; |
| 200 | if (flags & (GTF_reading|GTF_writing)) { |
| 201 | printk(KERN_ALERT "WARNING: g.e. still in use!\n"); |
| 202 | return 0; |
| 203 | } |
| 204 | } while ((nflags = sync_cmpxchg(&shared[ref].flags, flags, 0)) != flags); |
| 205 | |
| 206 | return 1; |
| 207 | } |
| 208 | EXPORT_SYMBOL_GPL(gnttab_end_foreign_access_ref); |
| 209 | |
| 210 | void gnttab_end_foreign_access(grant_ref_t ref, int readonly, |
| 211 | unsigned long page) |
| 212 | { |
| 213 | if (gnttab_end_foreign_access_ref(ref, readonly)) { |
| 214 | put_free_entry(ref); |
| 215 | if (page != 0) |
| 216 | free_page(page); |
| 217 | } else { |
| 218 | /* XXX This needs to be fixed so that the ref and page are |
| 219 | placed on a list to be freed up later. */ |
| 220 | printk(KERN_WARNING |
| 221 | "WARNING: leaking g.e. and page still in use!\n"); |
| 222 | } |
| 223 | } |
| 224 | EXPORT_SYMBOL_GPL(gnttab_end_foreign_access); |
| 225 | |
| 226 | int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn) |
| 227 | { |
| 228 | int ref; |
| 229 | |
| 230 | ref = get_free_entries(1); |
| 231 | if (unlikely(ref < 0)) |
| 232 | return -ENOSPC; |
| 233 | gnttab_grant_foreign_transfer_ref(ref, domid, pfn); |
| 234 | |
| 235 | return ref; |
| 236 | } |
| 237 | EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer); |
| 238 | |
| 239 | void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid, |
| 240 | unsigned long pfn) |
| 241 | { |
| 242 | update_grant_entry(ref, domid, pfn, GTF_accept_transfer); |
| 243 | } |
| 244 | EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref); |
| 245 | |
| 246 | unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref) |
| 247 | { |
| 248 | unsigned long frame; |
| 249 | u16 flags; |
| 250 | |
| 251 | /* |
| 252 | * If a transfer is not even yet started, try to reclaim the grant |
| 253 | * reference and return failure (== 0). |
| 254 | */ |
| 255 | while (!((flags = shared[ref].flags) & GTF_transfer_committed)) { |
| 256 | if (sync_cmpxchg(&shared[ref].flags, flags, 0) == flags) |
| 257 | return 0; |
| 258 | cpu_relax(); |
| 259 | } |
| 260 | |
| 261 | /* If a transfer is in progress then wait until it is completed. */ |
| 262 | while (!(flags & GTF_transfer_completed)) { |
| 263 | flags = shared[ref].flags; |
| 264 | cpu_relax(); |
| 265 | } |
| 266 | |
| 267 | rmb(); /* Read the frame number /after/ reading completion status. */ |
| 268 | frame = shared[ref].frame; |
| 269 | BUG_ON(frame == 0); |
| 270 | |
| 271 | return frame; |
| 272 | } |
| 273 | EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref); |
| 274 | |
| 275 | unsigned long gnttab_end_foreign_transfer(grant_ref_t ref) |
| 276 | { |
| 277 | unsigned long frame = gnttab_end_foreign_transfer_ref(ref); |
| 278 | put_free_entry(ref); |
| 279 | return frame; |
| 280 | } |
| 281 | EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer); |
| 282 | |
| 283 | void gnttab_free_grant_reference(grant_ref_t ref) |
| 284 | { |
| 285 | put_free_entry(ref); |
| 286 | } |
| 287 | EXPORT_SYMBOL_GPL(gnttab_free_grant_reference); |
| 288 | |
| 289 | void gnttab_free_grant_references(grant_ref_t head) |
| 290 | { |
| 291 | grant_ref_t ref; |
| 292 | unsigned long flags; |
| 293 | int count = 1; |
| 294 | if (head == GNTTAB_LIST_END) |
| 295 | return; |
| 296 | spin_lock_irqsave(&gnttab_list_lock, flags); |
| 297 | ref = head; |
| 298 | while (gnttab_entry(ref) != GNTTAB_LIST_END) { |
| 299 | ref = gnttab_entry(ref); |
| 300 | count++; |
| 301 | } |
| 302 | gnttab_entry(ref) = gnttab_free_head; |
| 303 | gnttab_free_head = head; |
| 304 | gnttab_free_count += count; |
| 305 | check_free_callbacks(); |
| 306 | spin_unlock_irqrestore(&gnttab_list_lock, flags); |
| 307 | } |
| 308 | EXPORT_SYMBOL_GPL(gnttab_free_grant_references); |
| 309 | |
| 310 | int gnttab_alloc_grant_references(u16 count, grant_ref_t *head) |
| 311 | { |
| 312 | int h = get_free_entries(count); |
| 313 | |
| 314 | if (h < 0) |
| 315 | return -ENOSPC; |
| 316 | |
| 317 | *head = h; |
| 318 | |
| 319 | return 0; |
| 320 | } |
| 321 | EXPORT_SYMBOL_GPL(gnttab_alloc_grant_references); |
| 322 | |
| 323 | int gnttab_empty_grant_references(const grant_ref_t *private_head) |
| 324 | { |
| 325 | return (*private_head == GNTTAB_LIST_END); |
| 326 | } |
| 327 | EXPORT_SYMBOL_GPL(gnttab_empty_grant_references); |
| 328 | |
| 329 | int gnttab_claim_grant_reference(grant_ref_t *private_head) |
| 330 | { |
| 331 | grant_ref_t g = *private_head; |
| 332 | if (unlikely(g == GNTTAB_LIST_END)) |
| 333 | return -ENOSPC; |
| 334 | *private_head = gnttab_entry(g); |
| 335 | return g; |
| 336 | } |
| 337 | EXPORT_SYMBOL_GPL(gnttab_claim_grant_reference); |
| 338 | |
| 339 | void gnttab_release_grant_reference(grant_ref_t *private_head, |
| 340 | grant_ref_t release) |
| 341 | { |
| 342 | gnttab_entry(release) = *private_head; |
| 343 | *private_head = release; |
| 344 | } |
| 345 | EXPORT_SYMBOL_GPL(gnttab_release_grant_reference); |
| 346 | |
| 347 | void gnttab_request_free_callback(struct gnttab_free_callback *callback, |
| 348 | void (*fn)(void *), void *arg, u16 count) |
| 349 | { |
| 350 | unsigned long flags; |
| 351 | spin_lock_irqsave(&gnttab_list_lock, flags); |
| 352 | if (callback->next) |
| 353 | goto out; |
| 354 | callback->fn = fn; |
| 355 | callback->arg = arg; |
| 356 | callback->count = count; |
| 357 | callback->next = gnttab_free_callback_list; |
| 358 | gnttab_free_callback_list = callback; |
| 359 | check_free_callbacks(); |
| 360 | out: |
| 361 | spin_unlock_irqrestore(&gnttab_list_lock, flags); |
| 362 | } |
| 363 | EXPORT_SYMBOL_GPL(gnttab_request_free_callback); |
| 364 | |
| 365 | void gnttab_cancel_free_callback(struct gnttab_free_callback *callback) |
| 366 | { |
| 367 | struct gnttab_free_callback **pcb; |
| 368 | unsigned long flags; |
| 369 | |
| 370 | spin_lock_irqsave(&gnttab_list_lock, flags); |
| 371 | for (pcb = &gnttab_free_callback_list; *pcb; pcb = &(*pcb)->next) { |
| 372 | if (*pcb == callback) { |
| 373 | *pcb = callback->next; |
| 374 | break; |
| 375 | } |
| 376 | } |
| 377 | spin_unlock_irqrestore(&gnttab_list_lock, flags); |
| 378 | } |
| 379 | EXPORT_SYMBOL_GPL(gnttab_cancel_free_callback); |
| 380 | |
| 381 | static int grow_gnttab_list(unsigned int more_frames) |
| 382 | { |
| 383 | unsigned int new_nr_grant_frames, extra_entries, i; |
Michael Abd-El-Malek | bbc60c1 | 2008-04-04 02:33:48 -0700 | [diff] [blame] | 384 | unsigned int nr_glist_frames, new_nr_glist_frames; |
Jeremy Fitzhardinge | ad9a861 | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 385 | |
| 386 | new_nr_grant_frames = nr_grant_frames + more_frames; |
| 387 | extra_entries = more_frames * GREFS_PER_GRANT_FRAME; |
| 388 | |
Michael Abd-El-Malek | bbc60c1 | 2008-04-04 02:33:48 -0700 | [diff] [blame] | 389 | nr_glist_frames = (nr_grant_frames * GREFS_PER_GRANT_FRAME + RPP - 1) / RPP; |
| 390 | new_nr_glist_frames = |
| 391 | (new_nr_grant_frames * GREFS_PER_GRANT_FRAME + RPP - 1) / RPP; |
| 392 | for (i = nr_glist_frames; i < new_nr_glist_frames; i++) { |
Jeremy Fitzhardinge | ad9a861 | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 393 | gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_ATOMIC); |
| 394 | if (!gnttab_list[i]) |
| 395 | goto grow_nomem; |
| 396 | } |
| 397 | |
| 398 | |
| 399 | for (i = GREFS_PER_GRANT_FRAME * nr_grant_frames; |
| 400 | i < GREFS_PER_GRANT_FRAME * new_nr_grant_frames - 1; i++) |
| 401 | gnttab_entry(i) = i + 1; |
| 402 | |
| 403 | gnttab_entry(i) = gnttab_free_head; |
| 404 | gnttab_free_head = GREFS_PER_GRANT_FRAME * nr_grant_frames; |
| 405 | gnttab_free_count += extra_entries; |
| 406 | |
| 407 | nr_grant_frames = new_nr_grant_frames; |
| 408 | |
| 409 | check_free_callbacks(); |
| 410 | |
| 411 | return 0; |
| 412 | |
| 413 | grow_nomem: |
Michael Abd-El-Malek | bbc60c1 | 2008-04-04 02:33:48 -0700 | [diff] [blame] | 414 | for ( ; i >= nr_glist_frames; i--) |
Jeremy Fitzhardinge | ad9a861 | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 415 | free_page((unsigned long) gnttab_list[i]); |
| 416 | return -ENOMEM; |
| 417 | } |
| 418 | |
| 419 | static unsigned int __max_nr_grant_frames(void) |
| 420 | { |
| 421 | struct gnttab_query_size query; |
| 422 | int rc; |
| 423 | |
| 424 | query.dom = DOMID_SELF; |
| 425 | |
| 426 | rc = HYPERVISOR_grant_table_op(GNTTABOP_query_size, &query, 1); |
| 427 | if ((rc < 0) || (query.status != GNTST_okay)) |
| 428 | return 4; /* Legacy max supported number of frames */ |
| 429 | |
| 430 | return query.max_nr_frames; |
| 431 | } |
| 432 | |
| 433 | static inline unsigned int max_nr_grant_frames(void) |
| 434 | { |
| 435 | unsigned int xen_max = __max_nr_grant_frames(); |
| 436 | |
| 437 | if (xen_max > boot_max_nr_grant_frames) |
| 438 | return boot_max_nr_grant_frames; |
| 439 | return xen_max; |
| 440 | } |
| 441 | |
| 442 | static int map_pte_fn(pte_t *pte, struct page *pmd_page, |
| 443 | unsigned long addr, void *data) |
| 444 | { |
| 445 | unsigned long **frames = (unsigned long **)data; |
| 446 | |
| 447 | set_pte_at(&init_mm, addr, pte, mfn_pte((*frames)[0], PAGE_KERNEL)); |
| 448 | (*frames)++; |
| 449 | return 0; |
| 450 | } |
| 451 | |
| 452 | static int unmap_pte_fn(pte_t *pte, struct page *pmd_page, |
| 453 | unsigned long addr, void *data) |
| 454 | { |
| 455 | |
| 456 | set_pte_at(&init_mm, addr, pte, __pte(0)); |
| 457 | return 0; |
| 458 | } |
| 459 | |
| 460 | static int gnttab_map(unsigned int start_idx, unsigned int end_idx) |
| 461 | { |
| 462 | struct gnttab_setup_table setup; |
| 463 | unsigned long *frames; |
| 464 | unsigned int nr_gframes = end_idx + 1; |
| 465 | int rc; |
| 466 | |
| 467 | frames = kmalloc(nr_gframes * sizeof(unsigned long), GFP_ATOMIC); |
| 468 | if (!frames) |
| 469 | return -ENOMEM; |
| 470 | |
| 471 | setup.dom = DOMID_SELF; |
| 472 | setup.nr_frames = nr_gframes; |
| 473 | setup.frame_list = frames; |
| 474 | |
| 475 | rc = HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1); |
| 476 | if (rc == -ENOSYS) { |
| 477 | kfree(frames); |
| 478 | return -ENOSYS; |
| 479 | } |
| 480 | |
| 481 | BUG_ON(rc || setup.status); |
| 482 | |
| 483 | if (shared == NULL) { |
| 484 | struct vm_struct *area; |
| 485 | area = alloc_vm_area(PAGE_SIZE * max_nr_grant_frames()); |
| 486 | BUG_ON(area == NULL); |
| 487 | shared = area->addr; |
| 488 | } |
| 489 | rc = apply_to_page_range(&init_mm, (unsigned long)shared, |
| 490 | PAGE_SIZE * nr_gframes, |
| 491 | map_pte_fn, &frames); |
| 492 | BUG_ON(rc); |
| 493 | frames -= nr_gframes; /* adjust after map_pte_fn() */ |
| 494 | |
| 495 | kfree(frames); |
| 496 | |
| 497 | return 0; |
| 498 | } |
| 499 | |
| 500 | static int gnttab_resume(void) |
| 501 | { |
| 502 | if (max_nr_grant_frames() < nr_grant_frames) |
| 503 | return -ENOSYS; |
| 504 | return gnttab_map(0, nr_grant_frames - 1); |
| 505 | } |
| 506 | |
| 507 | static int gnttab_suspend(void) |
| 508 | { |
| 509 | apply_to_page_range(&init_mm, (unsigned long)shared, |
| 510 | PAGE_SIZE * nr_grant_frames, |
| 511 | unmap_pte_fn, NULL); |
| 512 | |
| 513 | return 0; |
| 514 | } |
| 515 | |
| 516 | static int gnttab_expand(unsigned int req_entries) |
| 517 | { |
| 518 | int rc; |
| 519 | unsigned int cur, extra; |
| 520 | |
| 521 | cur = nr_grant_frames; |
| 522 | extra = ((req_entries + (GREFS_PER_GRANT_FRAME-1)) / |
| 523 | GREFS_PER_GRANT_FRAME); |
| 524 | if (cur + extra > max_nr_grant_frames()) |
| 525 | return -ENOSPC; |
| 526 | |
| 527 | rc = gnttab_map(cur, cur + extra - 1); |
| 528 | if (rc == 0) |
| 529 | rc = grow_gnttab_list(extra); |
| 530 | |
| 531 | return rc; |
| 532 | } |
| 533 | |
| 534 | static int __devinit gnttab_init(void) |
| 535 | { |
| 536 | int i; |
Michael Abd-El-Malek | bbc60c1 | 2008-04-04 02:33:48 -0700 | [diff] [blame] | 537 | unsigned int max_nr_glist_frames, nr_glist_frames; |
Jeremy Fitzhardinge | ad9a861 | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 538 | unsigned int nr_init_grefs; |
| 539 | |
| 540 | if (!is_running_on_xen()) |
| 541 | return -ENODEV; |
| 542 | |
| 543 | nr_grant_frames = 1; |
| 544 | boot_max_nr_grant_frames = __max_nr_grant_frames(); |
| 545 | |
| 546 | /* Determine the maximum number of frames required for the |
| 547 | * grant reference free list on the current hypervisor. |
| 548 | */ |
| 549 | max_nr_glist_frames = (boot_max_nr_grant_frames * |
Michael Abd-El-Malek | bbc60c1 | 2008-04-04 02:33:48 -0700 | [diff] [blame] | 550 | GREFS_PER_GRANT_FRAME / RPP); |
Jeremy Fitzhardinge | ad9a861 | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 551 | |
| 552 | gnttab_list = kmalloc(max_nr_glist_frames * sizeof(grant_ref_t *), |
| 553 | GFP_KERNEL); |
| 554 | if (gnttab_list == NULL) |
| 555 | return -ENOMEM; |
| 556 | |
Michael Abd-El-Malek | bbc60c1 | 2008-04-04 02:33:48 -0700 | [diff] [blame] | 557 | nr_glist_frames = (nr_grant_frames * GREFS_PER_GRANT_FRAME + RPP - 1) / RPP; |
| 558 | for (i = 0; i < nr_glist_frames; i++) { |
Jeremy Fitzhardinge | ad9a861 | 2007-07-17 18:37:06 -0700 | [diff] [blame] | 559 | gnttab_list[i] = (grant_ref_t *)__get_free_page(GFP_KERNEL); |
| 560 | if (gnttab_list[i] == NULL) |
| 561 | goto ini_nomem; |
| 562 | } |
| 563 | |
| 564 | if (gnttab_resume() < 0) |
| 565 | return -ENODEV; |
| 566 | |
| 567 | nr_init_grefs = nr_grant_frames * GREFS_PER_GRANT_FRAME; |
| 568 | |
| 569 | for (i = NR_RESERVED_ENTRIES; i < nr_init_grefs - 1; i++) |
| 570 | gnttab_entry(i) = i + 1; |
| 571 | |
| 572 | gnttab_entry(nr_init_grefs - 1) = GNTTAB_LIST_END; |
| 573 | gnttab_free_count = nr_init_grefs - NR_RESERVED_ENTRIES; |
| 574 | gnttab_free_head = NR_RESERVED_ENTRIES; |
| 575 | |
| 576 | printk("Grant table initialized\n"); |
| 577 | return 0; |
| 578 | |
| 579 | ini_nomem: |
| 580 | for (i--; i >= 0; i--) |
| 581 | free_page((unsigned long)gnttab_list[i]); |
| 582 | kfree(gnttab_list); |
| 583 | return -ENOMEM; |
| 584 | } |
| 585 | |
| 586 | core_initcall(gnttab_init); |