1 /* 2 * Copyright (c) 2012, Microsoft Corporation. 3 * 4 * Author: 5 * K. Y. Srinivasan <kys@microsoft.com> 6 * 7 * This program is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License version 2 as published 9 * by the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, but 12 * WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or 14 * NON INFRINGEMENT. See the GNU General Public License for more 15 * details. 16 * 17 */ 18 19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 20 21 #include <linux/kernel.h> 22 #include <linux/jiffies.h> 23 #include <linux/mman.h> 24 #include <linux/delay.h> 25 #include <linux/init.h> 26 #include <linux/module.h> 27 #include <linux/slab.h> 28 #include <linux/kthread.h> 29 #include <linux/completion.h> 30 #include <linux/memory_hotplug.h> 31 #include <linux/memory.h> 32 #include <linux/notifier.h> 33 #include <linux/percpu_counter.h> 34 35 #include <linux/hyperv.h> 36 37 /* 38 * We begin with definitions supporting the Dynamic Memory protocol 39 * with the host. 40 * 41 * Begin protocol definitions. 42 */ 43 44 45 46 /* 47 * Protocol versions. The low word is the minor version, the high word the major 48 * version. 49 * 50 * History: 51 * Initial version 1.0 52 * Changed to 0.1 on 2009/03/25 53 * Changes to 0.2 on 2009/05/14 54 * Changes to 0.3 on 2009/12/03 55 * Changed to 1.0 on 2011/04/05 56 */ 57 58 #define DYNMEM_MAKE_VERSION(Major, Minor) ((__u32)(((Major) << 16) | (Minor))) 59 #define DYNMEM_MAJOR_VERSION(Version) ((__u32)(Version) >> 16) 60 #define DYNMEM_MINOR_VERSION(Version) ((__u32)(Version) & 0xff) 61 62 enum { 63 DYNMEM_PROTOCOL_VERSION_1 = DYNMEM_MAKE_VERSION(0, 3), 64 DYNMEM_PROTOCOL_VERSION_2 = DYNMEM_MAKE_VERSION(1, 0), 65 DYNMEM_PROTOCOL_VERSION_3 = DYNMEM_MAKE_VERSION(2, 0), 66 67 DYNMEM_PROTOCOL_VERSION_WIN7 = DYNMEM_PROTOCOL_VERSION_1, 68 DYNMEM_PROTOCOL_VERSION_WIN8 = DYNMEM_PROTOCOL_VERSION_2, 69 DYNMEM_PROTOCOL_VERSION_WIN10 = DYNMEM_PROTOCOL_VERSION_3, 70 71 DYNMEM_PROTOCOL_VERSION_CURRENT = DYNMEM_PROTOCOL_VERSION_WIN10 72 }; 73 74 75 76 /* 77 * Message Types 78 */ 79 80 enum dm_message_type { 81 /* 82 * Version 0.3 83 */ 84 DM_ERROR = 0, 85 DM_VERSION_REQUEST = 1, 86 DM_VERSION_RESPONSE = 2, 87 DM_CAPABILITIES_REPORT = 3, 88 DM_CAPABILITIES_RESPONSE = 4, 89 DM_STATUS_REPORT = 5, 90 DM_BALLOON_REQUEST = 6, 91 DM_BALLOON_RESPONSE = 7, 92 DM_UNBALLOON_REQUEST = 8, 93 DM_UNBALLOON_RESPONSE = 9, 94 DM_MEM_HOT_ADD_REQUEST = 10, 95 DM_MEM_HOT_ADD_RESPONSE = 11, 96 DM_VERSION_03_MAX = 11, 97 /* 98 * Version 1.0. 99 */ 100 DM_INFO_MESSAGE = 12, 101 DM_VERSION_1_MAX = 12 102 }; 103 104 105 /* 106 * Structures defining the dynamic memory management 107 * protocol. 108 */ 109 110 union dm_version { 111 struct { 112 __u16 minor_version; 113 __u16 major_version; 114 }; 115 __u32 version; 116 } __packed; 117 118 119 union dm_caps { 120 struct { 121 __u64 balloon:1; 122 __u64 hot_add:1; 123 /* 124 * To support guests that may have alignment 125 * limitations on hot-add, the guest can specify 126 * its alignment requirements; a value of n 127 * represents an alignment of 2^n in mega bytes. 128 */ 129 __u64 hot_add_alignment:4; 130 __u64 reservedz:58; 131 } cap_bits; 132 __u64 caps; 133 } __packed; 134 135 union dm_mem_page_range { 136 struct { 137 /* 138 * The PFN number of the first page in the range. 139 * 40 bits is the architectural limit of a PFN 140 * number for AMD64. 141 */ 142 __u64 start_page:40; 143 /* 144 * The number of pages in the range. 145 */ 146 __u64 page_cnt:24; 147 } finfo; 148 __u64 page_range; 149 } __packed; 150 151 152 153 /* 154 * The header for all dynamic memory messages: 155 * 156 * type: Type of the message. 157 * size: Size of the message in bytes; including the header. 158 * trans_id: The guest is responsible for manufacturing this ID. 159 */ 160 161 struct dm_header { 162 __u16 type; 163 __u16 size; 164 __u32 trans_id; 165 } __packed; 166 167 /* 168 * A generic message format for dynamic memory. 169 * Specific message formats are defined later in the file. 170 */ 171 172 struct dm_message { 173 struct dm_header hdr; 174 __u8 data[]; /* enclosed message */ 175 } __packed; 176 177 178 /* 179 * Specific message types supporting the dynamic memory protocol. 180 */ 181 182 /* 183 * Version negotiation message. Sent from the guest to the host. 184 * The guest is free to try different versions until the host 185 * accepts the version. 186 * 187 * dm_version: The protocol version requested. 188 * is_last_attempt: If TRUE, this is the last version guest will request. 189 * reservedz: Reserved field, set to zero. 190 */ 191 192 struct dm_version_request { 193 struct dm_header hdr; 194 union dm_version version; 195 __u32 is_last_attempt:1; 196 __u32 reservedz:31; 197 } __packed; 198 199 /* 200 * Version response message; Host to Guest and indicates 201 * if the host has accepted the version sent by the guest. 202 * 203 * is_accepted: If TRUE, host has accepted the version and the guest 204 * should proceed to the next stage of the protocol. FALSE indicates that 205 * guest should re-try with a different version. 206 * 207 * reservedz: Reserved field, set to zero. 208 */ 209 210 struct dm_version_response { 211 struct dm_header hdr; 212 __u64 is_accepted:1; 213 __u64 reservedz:63; 214 } __packed; 215 216 /* 217 * Message reporting capabilities. This is sent from the guest to the 218 * host. 219 */ 220 221 struct dm_capabilities { 222 struct dm_header hdr; 223 union dm_caps caps; 224 __u64 min_page_cnt; 225 __u64 max_page_number; 226 } __packed; 227 228 /* 229 * Response to the capabilities message. This is sent from the host to the 230 * guest. This message notifies if the host has accepted the guest's 231 * capabilities. If the host has not accepted, the guest must shutdown 232 * the service. 233 * 234 * is_accepted: Indicates if the host has accepted guest's capabilities. 235 * reservedz: Must be 0. 236 */ 237 238 struct dm_capabilities_resp_msg { 239 struct dm_header hdr; 240 __u64 is_accepted:1; 241 __u64 reservedz:63; 242 } __packed; 243 244 /* 245 * This message is used to report memory pressure from the guest. 246 * This message is not part of any transaction and there is no 247 * response to this message. 248 * 249 * num_avail: Available memory in pages. 250 * num_committed: Committed memory in pages. 251 * page_file_size: The accumulated size of all page files 252 * in the system in pages. 253 * zero_free: The nunber of zero and free pages. 254 * page_file_writes: The writes to the page file in pages. 255 * io_diff: An indicator of file cache efficiency or page file activity, 256 * calculated as File Cache Page Fault Count - Page Read Count. 257 * This value is in pages. 258 * 259 * Some of these metrics are Windows specific and fortunately 260 * the algorithm on the host side that computes the guest memory 261 * pressure only uses num_committed value. 262 */ 263 264 struct dm_status { 265 struct dm_header hdr; 266 __u64 num_avail; 267 __u64 num_committed; 268 __u64 page_file_size; 269 __u64 zero_free; 270 __u32 page_file_writes; 271 __u32 io_diff; 272 } __packed; 273 274 275 /* 276 * Message to ask the guest to allocate memory - balloon up message. 277 * This message is sent from the host to the guest. The guest may not be 278 * able to allocate as much memory as requested. 279 * 280 * num_pages: number of pages to allocate. 281 */ 282 283 struct dm_balloon { 284 struct dm_header hdr; 285 __u32 num_pages; 286 __u32 reservedz; 287 } __packed; 288 289 290 /* 291 * Balloon response message; this message is sent from the guest 292 * to the host in response to the balloon message. 293 * 294 * reservedz: Reserved; must be set to zero. 295 * more_pages: If FALSE, this is the last message of the transaction. 296 * if TRUE there will atleast one more message from the guest. 297 * 298 * range_count: The number of ranges in the range array. 299 * 300 * range_array: An array of page ranges returned to the host. 301 * 302 */ 303 304 struct dm_balloon_response { 305 struct dm_header hdr; 306 __u32 reservedz; 307 __u32 more_pages:1; 308 __u32 range_count:31; 309 union dm_mem_page_range range_array[]; 310 } __packed; 311 312 /* 313 * Un-balloon message; this message is sent from the host 314 * to the guest to give guest more memory. 315 * 316 * more_pages: If FALSE, this is the last message of the transaction. 317 * if TRUE there will atleast one more message from the guest. 318 * 319 * reservedz: Reserved; must be set to zero. 320 * 321 * range_count: The number of ranges in the range array. 322 * 323 * range_array: An array of page ranges returned to the host. 324 * 325 */ 326 327 struct dm_unballoon_request { 328 struct dm_header hdr; 329 __u32 more_pages:1; 330 __u32 reservedz:31; 331 __u32 range_count; 332 union dm_mem_page_range range_array[]; 333 } __packed; 334 335 /* 336 * Un-balloon response message; this message is sent from the guest 337 * to the host in response to an unballoon request. 338 * 339 */ 340 341 struct dm_unballoon_response { 342 struct dm_header hdr; 343 } __packed; 344 345 346 /* 347 * Hot add request message. Message sent from the host to the guest. 348 * 349 * mem_range: Memory range to hot add. 350 * 351 * On Linux we currently don't support this since we cannot hot add 352 * arbitrary granularity of memory. 353 */ 354 355 struct dm_hot_add { 356 struct dm_header hdr; 357 union dm_mem_page_range range; 358 } __packed; 359 360 /* 361 * Hot add response message. 362 * This message is sent by the guest to report the status of a hot add request. 363 * If page_count is less than the requested page count, then the host should 364 * assume all further hot add requests will fail, since this indicates that 365 * the guest has hit an upper physical memory barrier. 366 * 367 * Hot adds may also fail due to low resources; in this case, the guest must 368 * not complete this message until the hot add can succeed, and the host must 369 * not send a new hot add request until the response is sent. 370 * If VSC fails to hot add memory DYNMEM_NUMBER_OF_UNSUCCESSFUL_HOTADD_ATTEMPTS 371 * times it fails the request. 372 * 373 * 374 * page_count: number of pages that were successfully hot added. 375 * 376 * result: result of the operation 1: success, 0: failure. 377 * 378 */ 379 380 struct dm_hot_add_response { 381 struct dm_header hdr; 382 __u32 page_count; 383 __u32 result; 384 } __packed; 385 386 /* 387 * Types of information sent from host to the guest. 388 */ 389 390 enum dm_info_type { 391 INFO_TYPE_MAX_PAGE_CNT = 0, 392 MAX_INFO_TYPE 393 }; 394 395 396 /* 397 * Header for the information message. 398 */ 399 400 struct dm_info_header { 401 enum dm_info_type type; 402 __u32 data_size; 403 } __packed; 404 405 /* 406 * This message is sent from the host to the guest to pass 407 * some relevant information (win8 addition). 408 * 409 * reserved: no used. 410 * info_size: size of the information blob. 411 * info: information blob. 412 */ 413 414 struct dm_info_msg { 415 struct dm_header hdr; 416 __u32 reserved; 417 __u32 info_size; 418 __u8 info[]; 419 }; 420 421 /* 422 * End protocol definitions. 423 */ 424 425 /* 426 * State to manage hot adding memory into the guest. 427 * The range start_pfn : end_pfn specifies the range 428 * that the host has asked us to hot add. The range 429 * start_pfn : ha_end_pfn specifies the range that we have 430 * currently hot added. We hot add in multiples of 128M 431 * chunks; it is possible that we may not be able to bring 432 * online all the pages in the region. The range 433 * covered_end_pfn defines the pages that can 434 * be brough online. 435 */ 436 437 struct hv_hotadd_state { 438 struct list_head list; 439 unsigned long start_pfn; 440 unsigned long covered_end_pfn; 441 unsigned long ha_end_pfn; 442 unsigned long end_pfn; 443 }; 444 445 struct balloon_state { 446 __u32 num_pages; 447 struct work_struct wrk; 448 }; 449 450 struct hot_add_wrk { 451 union dm_mem_page_range ha_page_range; 452 union dm_mem_page_range ha_region_range; 453 struct work_struct wrk; 454 }; 455 456 static bool hot_add = true; 457 static bool do_hot_add; 458 /* 459 * Delay reporting memory pressure by 460 * the specified number of seconds. 461 */ 462 static uint pressure_report_delay = 45; 463 464 /* 465 * The last time we posted a pressure report to host. 466 */ 467 static unsigned long last_post_time; 468 469 module_param(hot_add, bool, (S_IRUGO | S_IWUSR)); 470 MODULE_PARM_DESC(hot_add, "If set attempt memory hot_add"); 471 472 module_param(pressure_report_delay, uint, (S_IRUGO | S_IWUSR)); 473 MODULE_PARM_DESC(pressure_report_delay, "Delay in secs in reporting pressure"); 474 static atomic_t trans_id = ATOMIC_INIT(0); 475 476 static int dm_ring_size = (5 * PAGE_SIZE); 477 478 /* 479 * Driver specific state. 480 */ 481 482 enum hv_dm_state { 483 DM_INITIALIZING = 0, 484 DM_INITIALIZED, 485 DM_BALLOON_UP, 486 DM_BALLOON_DOWN, 487 DM_HOT_ADD, 488 DM_INIT_ERROR 489 }; 490 491 492 static __u8 recv_buffer[PAGE_SIZE]; 493 static __u8 *send_buffer; 494 #define PAGES_IN_2M 512 495 #define HA_CHUNK (32 * 1024) 496 497 struct hv_dynmem_device { 498 struct hv_device *dev; 499 enum hv_dm_state state; 500 struct completion host_event; 501 struct completion config_event; 502 503 /* 504 * Number of pages we have currently ballooned out. 505 */ 506 unsigned int num_pages_ballooned; 507 unsigned int num_pages_onlined; 508 unsigned int num_pages_added; 509 510 /* 511 * State to manage the ballooning (up) operation. 512 */ 513 struct balloon_state balloon_wrk; 514 515 /* 516 * State to execute the "hot-add" operation. 517 */ 518 struct hot_add_wrk ha_wrk; 519 520 /* 521 * This state tracks if the host has specified a hot-add 522 * region. 523 */ 524 bool host_specified_ha_region; 525 526 /* 527 * State to synchronize hot-add. 528 */ 529 struct completion ol_waitevent; 530 bool ha_waiting; 531 /* 532 * This thread handles hot-add 533 * requests from the host as well as notifying 534 * the host with regards to memory pressure in 535 * the guest. 536 */ 537 struct task_struct *thread; 538 539 struct mutex ha_region_mutex; 540 541 /* 542 * A list of hot-add regions. 543 */ 544 struct list_head ha_region_list; 545 546 /* 547 * We start with the highest version we can support 548 * and downgrade based on the host; we save here the 549 * next version to try. 550 */ 551 __u32 next_version; 552 }; 553 554 static struct hv_dynmem_device dm_device; 555 556 static void post_status(struct hv_dynmem_device *dm); 557 558 #ifdef CONFIG_MEMORY_HOTPLUG 559 static int hv_memory_notifier(struct notifier_block *nb, unsigned long val, 560 void *v) 561 { 562 struct memory_notify *mem = (struct memory_notify *)v; 563 564 switch (val) { 565 case MEM_GOING_ONLINE: 566 mutex_lock(&dm_device.ha_region_mutex); 567 break; 568 569 case MEM_ONLINE: 570 dm_device.num_pages_onlined += mem->nr_pages; 571 case MEM_CANCEL_ONLINE: 572 if (val == MEM_ONLINE || 573 mutex_is_locked(&dm_device.ha_region_mutex)) 574 mutex_unlock(&dm_device.ha_region_mutex); 575 if (dm_device.ha_waiting) { 576 dm_device.ha_waiting = false; 577 complete(&dm_device.ol_waitevent); 578 } 579 break; 580 581 case MEM_OFFLINE: 582 mutex_lock(&dm_device.ha_region_mutex); 583 dm_device.num_pages_onlined -= mem->nr_pages; 584 mutex_unlock(&dm_device.ha_region_mutex); 585 break; 586 case MEM_GOING_OFFLINE: 587 case MEM_CANCEL_OFFLINE: 588 break; 589 } 590 return NOTIFY_OK; 591 } 592 593 static struct notifier_block hv_memory_nb = { 594 .notifier_call = hv_memory_notifier, 595 .priority = 0 596 }; 597 598 599 static void hv_bring_pgs_online(unsigned long start_pfn, unsigned long size) 600 { 601 int i; 602 603 for (i = 0; i < size; i++) { 604 struct page *pg; 605 pg = pfn_to_page(start_pfn + i); 606 __online_page_set_limits(pg); 607 __online_page_increment_counters(pg); 608 __online_page_free(pg); 609 } 610 } 611 612 static void hv_mem_hot_add(unsigned long start, unsigned long size, 613 unsigned long pfn_count, 614 struct hv_hotadd_state *has) 615 { 616 int ret = 0; 617 int i, nid; 618 unsigned long start_pfn; 619 unsigned long processed_pfn; 620 unsigned long total_pfn = pfn_count; 621 622 for (i = 0; i < (size/HA_CHUNK); i++) { 623 start_pfn = start + (i * HA_CHUNK); 624 has->ha_end_pfn += HA_CHUNK; 625 626 if (total_pfn > HA_CHUNK) { 627 processed_pfn = HA_CHUNK; 628 total_pfn -= HA_CHUNK; 629 } else { 630 processed_pfn = total_pfn; 631 total_pfn = 0; 632 } 633 634 has->covered_end_pfn += processed_pfn; 635 636 init_completion(&dm_device.ol_waitevent); 637 dm_device.ha_waiting = true; 638 639 mutex_unlock(&dm_device.ha_region_mutex); 640 nid = memory_add_physaddr_to_nid(PFN_PHYS(start_pfn)); 641 ret = add_memory(nid, PFN_PHYS((start_pfn)), 642 (HA_CHUNK << PAGE_SHIFT)); 643 644 if (ret) { 645 pr_info("hot_add memory failed error is %d\n", ret); 646 if (ret == -EEXIST) { 647 /* 648 * This error indicates that the error 649 * is not a transient failure. This is the 650 * case where the guest's physical address map 651 * precludes hot adding memory. Stop all further 652 * memory hot-add. 653 */ 654 do_hot_add = false; 655 } 656 has->ha_end_pfn -= HA_CHUNK; 657 has->covered_end_pfn -= processed_pfn; 658 mutex_lock(&dm_device.ha_region_mutex); 659 break; 660 } 661 662 /* 663 * Wait for the memory block to be onlined. 664 * Since the hot add has succeeded, it is ok to 665 * proceed even if the pages in the hot added region 666 * have not been "onlined" within the allowed time. 667 */ 668 wait_for_completion_timeout(&dm_device.ol_waitevent, 5*HZ); 669 mutex_lock(&dm_device.ha_region_mutex); 670 post_status(&dm_device); 671 } 672 673 return; 674 } 675 676 static void hv_online_page(struct page *pg) 677 { 678 struct list_head *cur; 679 struct hv_hotadd_state *has; 680 unsigned long cur_start_pgp; 681 unsigned long cur_end_pgp; 682 683 list_for_each(cur, &dm_device.ha_region_list) { 684 has = list_entry(cur, struct hv_hotadd_state, list); 685 cur_start_pgp = (unsigned long)pfn_to_page(has->start_pfn); 686 cur_end_pgp = (unsigned long)pfn_to_page(has->covered_end_pfn); 687 688 if (((unsigned long)pg >= cur_start_pgp) && 689 ((unsigned long)pg < cur_end_pgp)) { 690 /* 691 * This frame is currently backed; online the 692 * page. 693 */ 694 __online_page_set_limits(pg); 695 __online_page_increment_counters(pg); 696 __online_page_free(pg); 697 } 698 } 699 } 700 701 static bool pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt) 702 { 703 struct list_head *cur; 704 struct hv_hotadd_state *has; 705 unsigned long residual, new_inc; 706 707 if (list_empty(&dm_device.ha_region_list)) 708 return false; 709 710 list_for_each(cur, &dm_device.ha_region_list) { 711 has = list_entry(cur, struct hv_hotadd_state, list); 712 713 /* 714 * If the pfn range we are dealing with is not in the current 715 * "hot add block", move on. 716 */ 717 if ((start_pfn >= has->end_pfn)) 718 continue; 719 /* 720 * If the current hot add-request extends beyond 721 * our current limit; extend it. 722 */ 723 if ((start_pfn + pfn_cnt) > has->end_pfn) { 724 residual = (start_pfn + pfn_cnt - has->end_pfn); 725 /* 726 * Extend the region by multiples of HA_CHUNK. 727 */ 728 new_inc = (residual / HA_CHUNK) * HA_CHUNK; 729 if (residual % HA_CHUNK) 730 new_inc += HA_CHUNK; 731 732 has->end_pfn += new_inc; 733 } 734 735 /* 736 * If the current start pfn is not where the covered_end 737 * is, update it. 738 */ 739 740 if (has->covered_end_pfn != start_pfn) 741 has->covered_end_pfn = start_pfn; 742 743 return true; 744 745 } 746 747 return false; 748 } 749 750 static unsigned long handle_pg_range(unsigned long pg_start, 751 unsigned long pg_count) 752 { 753 unsigned long start_pfn = pg_start; 754 unsigned long pfn_cnt = pg_count; 755 unsigned long size; 756 struct list_head *cur; 757 struct hv_hotadd_state *has; 758 unsigned long pgs_ol = 0; 759 unsigned long old_covered_state; 760 761 if (list_empty(&dm_device.ha_region_list)) 762 return 0; 763 764 list_for_each(cur, &dm_device.ha_region_list) { 765 has = list_entry(cur, struct hv_hotadd_state, list); 766 767 /* 768 * If the pfn range we are dealing with is not in the current 769 * "hot add block", move on. 770 */ 771 if ((start_pfn >= has->end_pfn)) 772 continue; 773 774 old_covered_state = has->covered_end_pfn; 775 776 if (start_pfn < has->ha_end_pfn) { 777 /* 778 * This is the case where we are backing pages 779 * in an already hot added region. Bring 780 * these pages online first. 781 */ 782 pgs_ol = has->ha_end_pfn - start_pfn; 783 if (pgs_ol > pfn_cnt) 784 pgs_ol = pfn_cnt; 785 786 /* 787 * Check if the corresponding memory block is already 788 * online by checking its last previously backed page. 789 * In case it is we need to bring rest (which was not 790 * backed previously) online too. 791 */ 792 if (start_pfn > has->start_pfn && 793 !PageReserved(pfn_to_page(start_pfn - 1))) 794 hv_bring_pgs_online(start_pfn, pgs_ol); 795 796 has->covered_end_pfn += pgs_ol; 797 pfn_cnt -= pgs_ol; 798 } 799 800 if ((has->ha_end_pfn < has->end_pfn) && (pfn_cnt > 0)) { 801 /* 802 * We have some residual hot add range 803 * that needs to be hot added; hot add 804 * it now. Hot add a multiple of 805 * of HA_CHUNK that fully covers the pages 806 * we have. 807 */ 808 size = (has->end_pfn - has->ha_end_pfn); 809 if (pfn_cnt <= size) { 810 size = ((pfn_cnt / HA_CHUNK) * HA_CHUNK); 811 if (pfn_cnt % HA_CHUNK) 812 size += HA_CHUNK; 813 } else { 814 pfn_cnt = size; 815 } 816 hv_mem_hot_add(has->ha_end_pfn, size, pfn_cnt, has); 817 } 818 /* 819 * If we managed to online any pages that were given to us, 820 * we declare success. 821 */ 822 return has->covered_end_pfn - old_covered_state; 823 824 } 825 826 return 0; 827 } 828 829 static unsigned long process_hot_add(unsigned long pg_start, 830 unsigned long pfn_cnt, 831 unsigned long rg_start, 832 unsigned long rg_size) 833 { 834 struct hv_hotadd_state *ha_region = NULL; 835 836 if (pfn_cnt == 0) 837 return 0; 838 839 if (!dm_device.host_specified_ha_region) 840 if (pfn_covered(pg_start, pfn_cnt)) 841 goto do_pg_range; 842 843 /* 844 * If the host has specified a hot-add range; deal with it first. 845 */ 846 847 if (rg_size != 0) { 848 ha_region = kzalloc(sizeof(struct hv_hotadd_state), GFP_KERNEL); 849 if (!ha_region) 850 return 0; 851 852 INIT_LIST_HEAD(&ha_region->list); 853 854 list_add_tail(&ha_region->list, &dm_device.ha_region_list); 855 ha_region->start_pfn = rg_start; 856 ha_region->ha_end_pfn = rg_start; 857 ha_region->covered_end_pfn = pg_start; 858 ha_region->end_pfn = rg_start + rg_size; 859 } 860 861 do_pg_range: 862 /* 863 * Process the page range specified; bringing them 864 * online if possible. 865 */ 866 return handle_pg_range(pg_start, pfn_cnt); 867 } 868 869 #endif 870 871 static void hot_add_req(struct work_struct *dummy) 872 { 873 struct dm_hot_add_response resp; 874 #ifdef CONFIG_MEMORY_HOTPLUG 875 unsigned long pg_start, pfn_cnt; 876 unsigned long rg_start, rg_sz; 877 #endif 878 struct hv_dynmem_device *dm = &dm_device; 879 880 memset(&resp, 0, sizeof(struct dm_hot_add_response)); 881 resp.hdr.type = DM_MEM_HOT_ADD_RESPONSE; 882 resp.hdr.size = sizeof(struct dm_hot_add_response); 883 884 #ifdef CONFIG_MEMORY_HOTPLUG 885 mutex_lock(&dm_device.ha_region_mutex); 886 pg_start = dm->ha_wrk.ha_page_range.finfo.start_page; 887 pfn_cnt = dm->ha_wrk.ha_page_range.finfo.page_cnt; 888 889 rg_start = dm->ha_wrk.ha_region_range.finfo.start_page; 890 rg_sz = dm->ha_wrk.ha_region_range.finfo.page_cnt; 891 892 if ((rg_start == 0) && (!dm->host_specified_ha_region)) { 893 unsigned long region_size; 894 unsigned long region_start; 895 896 /* 897 * The host has not specified the hot-add region. 898 * Based on the hot-add page range being specified, 899 * compute a hot-add region that can cover the pages 900 * that need to be hot-added while ensuring the alignment 901 * and size requirements of Linux as it relates to hot-add. 902 */ 903 region_start = pg_start; 904 region_size = (pfn_cnt / HA_CHUNK) * HA_CHUNK; 905 if (pfn_cnt % HA_CHUNK) 906 region_size += HA_CHUNK; 907 908 region_start = (pg_start / HA_CHUNK) * HA_CHUNK; 909 910 rg_start = region_start; 911 rg_sz = region_size; 912 } 913 914 if (do_hot_add) 915 resp.page_count = process_hot_add(pg_start, pfn_cnt, 916 rg_start, rg_sz); 917 918 dm->num_pages_added += resp.page_count; 919 mutex_unlock(&dm_device.ha_region_mutex); 920 #endif 921 /* 922 * The result field of the response structure has the 923 * following semantics: 924 * 925 * 1. If all or some pages hot-added: Guest should return success. 926 * 927 * 2. If no pages could be hot-added: 928 * 929 * If the guest returns success, then the host 930 * will not attempt any further hot-add operations. This 931 * signifies a permanent failure. 932 * 933 * If the guest returns failure, then this failure will be 934 * treated as a transient failure and the host may retry the 935 * hot-add operation after some delay. 936 */ 937 if (resp.page_count > 0) 938 resp.result = 1; 939 else if (!do_hot_add) 940 resp.result = 1; 941 else 942 resp.result = 0; 943 944 if (!do_hot_add || (resp.page_count == 0)) 945 pr_info("Memory hot add failed\n"); 946 947 dm->state = DM_INITIALIZED; 948 resp.hdr.trans_id = atomic_inc_return(&trans_id); 949 vmbus_sendpacket(dm->dev->channel, &resp, 950 sizeof(struct dm_hot_add_response), 951 (unsigned long)NULL, 952 VM_PKT_DATA_INBAND, 0); 953 } 954 955 static void process_info(struct hv_dynmem_device *dm, struct dm_info_msg *msg) 956 { 957 struct dm_info_header *info_hdr; 958 959 info_hdr = (struct dm_info_header *)msg->info; 960 961 switch (info_hdr->type) { 962 case INFO_TYPE_MAX_PAGE_CNT: 963 pr_info("Received INFO_TYPE_MAX_PAGE_CNT\n"); 964 pr_info("Data Size is %d\n", info_hdr->data_size); 965 break; 966 default: 967 pr_info("Received Unknown type: %d\n", info_hdr->type); 968 } 969 } 970 971 static unsigned long compute_balloon_floor(void) 972 { 973 unsigned long min_pages; 974 #define MB2PAGES(mb) ((mb) << (20 - PAGE_SHIFT)) 975 /* Simple continuous piecewiese linear function: 976 * max MiB -> min MiB gradient 977 * 0 0 978 * 16 16 979 * 32 24 980 * 128 72 (1/2) 981 * 512 168 (1/4) 982 * 2048 360 (1/8) 983 * 8192 744 (1/16) 984 * 32768 1512 (1/32) 985 */ 986 if (totalram_pages < MB2PAGES(128)) 987 min_pages = MB2PAGES(8) + (totalram_pages >> 1); 988 else if (totalram_pages < MB2PAGES(512)) 989 min_pages = MB2PAGES(40) + (totalram_pages >> 2); 990 else if (totalram_pages < MB2PAGES(2048)) 991 min_pages = MB2PAGES(104) + (totalram_pages >> 3); 992 else if (totalram_pages < MB2PAGES(8192)) 993 min_pages = MB2PAGES(232) + (totalram_pages >> 4); 994 else 995 min_pages = MB2PAGES(488) + (totalram_pages >> 5); 996 #undef MB2PAGES 997 return min_pages; 998 } 999 1000 /* 1001 * Post our status as it relates memory pressure to the 1002 * host. Host expects the guests to post this status 1003 * periodically at 1 second intervals. 1004 * 1005 * The metrics specified in this protocol are very Windows 1006 * specific and so we cook up numbers here to convey our memory 1007 * pressure. 1008 */ 1009 1010 static void post_status(struct hv_dynmem_device *dm) 1011 { 1012 struct dm_status status; 1013 struct sysinfo val; 1014 unsigned long now = jiffies; 1015 unsigned long last_post = last_post_time; 1016 1017 if (pressure_report_delay > 0) { 1018 --pressure_report_delay; 1019 return; 1020 } 1021 1022 if (!time_after(now, (last_post_time + HZ))) 1023 return; 1024 1025 si_meminfo(&val); 1026 memset(&status, 0, sizeof(struct dm_status)); 1027 status.hdr.type = DM_STATUS_REPORT; 1028 status.hdr.size = sizeof(struct dm_status); 1029 status.hdr.trans_id = atomic_inc_return(&trans_id); 1030 1031 /* 1032 * The host expects the guest to report free and committed memory. 1033 * Furthermore, the host expects the pressure information to include 1034 * the ballooned out pages. For a given amount of memory that we are 1035 * managing we need to compute a floor below which we should not 1036 * balloon. Compute this and add it to the pressure report. 1037 * We also need to report all offline pages (num_pages_added - 1038 * num_pages_onlined) as committed to the host, otherwise it can try 1039 * asking us to balloon them out. 1040 */ 1041 status.num_avail = val.freeram; 1042 status.num_committed = vm_memory_committed() + 1043 dm->num_pages_ballooned + 1044 (dm->num_pages_added > dm->num_pages_onlined ? 1045 dm->num_pages_added - dm->num_pages_onlined : 0) + 1046 compute_balloon_floor(); 1047 1048 /* 1049 * If our transaction ID is no longer current, just don't 1050 * send the status. This can happen if we were interrupted 1051 * after we picked our transaction ID. 1052 */ 1053 if (status.hdr.trans_id != atomic_read(&trans_id)) 1054 return; 1055 1056 /* 1057 * If the last post time that we sampled has changed, 1058 * we have raced, don't post the status. 1059 */ 1060 if (last_post != last_post_time) 1061 return; 1062 1063 last_post_time = jiffies; 1064 vmbus_sendpacket(dm->dev->channel, &status, 1065 sizeof(struct dm_status), 1066 (unsigned long)NULL, 1067 VM_PKT_DATA_INBAND, 0); 1068 1069 } 1070 1071 static void free_balloon_pages(struct hv_dynmem_device *dm, 1072 union dm_mem_page_range *range_array) 1073 { 1074 int num_pages = range_array->finfo.page_cnt; 1075 __u64 start_frame = range_array->finfo.start_page; 1076 struct page *pg; 1077 int i; 1078 1079 for (i = 0; i < num_pages; i++) { 1080 pg = pfn_to_page(i + start_frame); 1081 __free_page(pg); 1082 dm->num_pages_ballooned--; 1083 } 1084 } 1085 1086 1087 1088 static unsigned int alloc_balloon_pages(struct hv_dynmem_device *dm, 1089 unsigned int num_pages, 1090 struct dm_balloon_response *bl_resp, 1091 int alloc_unit) 1092 { 1093 unsigned int i = 0; 1094 struct page *pg; 1095 1096 if (num_pages < alloc_unit) 1097 return 0; 1098 1099 for (i = 0; (i * alloc_unit) < num_pages; i++) { 1100 if (bl_resp->hdr.size + sizeof(union dm_mem_page_range) > 1101 PAGE_SIZE) 1102 return i * alloc_unit; 1103 1104 /* 1105 * We execute this code in a thread context. Furthermore, 1106 * we don't want the kernel to try too hard. 1107 */ 1108 pg = alloc_pages(GFP_HIGHUSER | __GFP_NORETRY | 1109 __GFP_NOMEMALLOC | __GFP_NOWARN, 1110 get_order(alloc_unit << PAGE_SHIFT)); 1111 1112 if (!pg) 1113 return i * alloc_unit; 1114 1115 dm->num_pages_ballooned += alloc_unit; 1116 1117 /* 1118 * If we allocatted 2M pages; split them so we 1119 * can free them in any order we get. 1120 */ 1121 1122 if (alloc_unit != 1) 1123 split_page(pg, get_order(alloc_unit << PAGE_SHIFT)); 1124 1125 bl_resp->range_count++; 1126 bl_resp->range_array[i].finfo.start_page = 1127 page_to_pfn(pg); 1128 bl_resp->range_array[i].finfo.page_cnt = alloc_unit; 1129 bl_resp->hdr.size += sizeof(union dm_mem_page_range); 1130 1131 } 1132 1133 return num_pages; 1134 } 1135 1136 1137 1138 static void balloon_up(struct work_struct *dummy) 1139 { 1140 unsigned int num_pages = dm_device.balloon_wrk.num_pages; 1141 unsigned int num_ballooned = 0; 1142 struct dm_balloon_response *bl_resp; 1143 int alloc_unit; 1144 int ret; 1145 bool done = false; 1146 int i; 1147 struct sysinfo val; 1148 unsigned long floor; 1149 1150 /* The host balloons pages in 2M granularity. */ 1151 WARN_ON_ONCE(num_pages % PAGES_IN_2M != 0); 1152 1153 /* 1154 * We will attempt 2M allocations. However, if we fail to 1155 * allocate 2M chunks, we will go back to 4k allocations. 1156 */ 1157 alloc_unit = 512; 1158 1159 si_meminfo(&val); 1160 floor = compute_balloon_floor(); 1161 1162 /* Refuse to balloon below the floor, keep the 2M granularity. */ 1163 if (val.freeram < num_pages || val.freeram - num_pages < floor) { 1164 num_pages = val.freeram > floor ? (val.freeram - floor) : 0; 1165 num_pages -= num_pages % PAGES_IN_2M; 1166 } 1167 1168 while (!done) { 1169 bl_resp = (struct dm_balloon_response *)send_buffer; 1170 memset(send_buffer, 0, PAGE_SIZE); 1171 bl_resp->hdr.type = DM_BALLOON_RESPONSE; 1172 bl_resp->hdr.size = sizeof(struct dm_balloon_response); 1173 bl_resp->more_pages = 1; 1174 1175 1176 num_pages -= num_ballooned; 1177 num_ballooned = alloc_balloon_pages(&dm_device, num_pages, 1178 bl_resp, alloc_unit); 1179 1180 if (alloc_unit != 1 && num_ballooned == 0) { 1181 alloc_unit = 1; 1182 continue; 1183 } 1184 1185 if (num_ballooned == 0 || num_ballooned == num_pages) { 1186 bl_resp->more_pages = 0; 1187 done = true; 1188 dm_device.state = DM_INITIALIZED; 1189 } 1190 1191 /* 1192 * We are pushing a lot of data through the channel; 1193 * deal with transient failures caused because of the 1194 * lack of space in the ring buffer. 1195 */ 1196 1197 do { 1198 bl_resp->hdr.trans_id = atomic_inc_return(&trans_id); 1199 ret = vmbus_sendpacket(dm_device.dev->channel, 1200 bl_resp, 1201 bl_resp->hdr.size, 1202 (unsigned long)NULL, 1203 VM_PKT_DATA_INBAND, 0); 1204 1205 if (ret == -EAGAIN) 1206 msleep(20); 1207 post_status(&dm_device); 1208 } while (ret == -EAGAIN); 1209 1210 if (ret) { 1211 /* 1212 * Free up the memory we allocatted. 1213 */ 1214 pr_info("Balloon response failed\n"); 1215 1216 for (i = 0; i < bl_resp->range_count; i++) 1217 free_balloon_pages(&dm_device, 1218 &bl_resp->range_array[i]); 1219 1220 done = true; 1221 } 1222 } 1223 1224 } 1225 1226 static void balloon_down(struct hv_dynmem_device *dm, 1227 struct dm_unballoon_request *req) 1228 { 1229 union dm_mem_page_range *range_array = req->range_array; 1230 int range_count = req->range_count; 1231 struct dm_unballoon_response resp; 1232 int i; 1233 1234 for (i = 0; i < range_count; i++) { 1235 free_balloon_pages(dm, &range_array[i]); 1236 complete(&dm_device.config_event); 1237 } 1238 1239 if (req->more_pages == 1) 1240 return; 1241 1242 memset(&resp, 0, sizeof(struct dm_unballoon_response)); 1243 resp.hdr.type = DM_UNBALLOON_RESPONSE; 1244 resp.hdr.trans_id = atomic_inc_return(&trans_id); 1245 resp.hdr.size = sizeof(struct dm_unballoon_response); 1246 1247 vmbus_sendpacket(dm_device.dev->channel, &resp, 1248 sizeof(struct dm_unballoon_response), 1249 (unsigned long)NULL, 1250 VM_PKT_DATA_INBAND, 0); 1251 1252 dm->state = DM_INITIALIZED; 1253 } 1254 1255 static void balloon_onchannelcallback(void *context); 1256 1257 static int dm_thread_func(void *dm_dev) 1258 { 1259 struct hv_dynmem_device *dm = dm_dev; 1260 1261 while (!kthread_should_stop()) { 1262 wait_for_completion_interruptible_timeout( 1263 &dm_device.config_event, 1*HZ); 1264 /* 1265 * The host expects us to post information on the memory 1266 * pressure every second. 1267 */ 1268 reinit_completion(&dm_device.config_event); 1269 post_status(dm); 1270 } 1271 1272 return 0; 1273 } 1274 1275 1276 static void version_resp(struct hv_dynmem_device *dm, 1277 struct dm_version_response *vresp) 1278 { 1279 struct dm_version_request version_req; 1280 int ret; 1281 1282 if (vresp->is_accepted) { 1283 /* 1284 * We are done; wakeup the 1285 * context waiting for version 1286 * negotiation. 1287 */ 1288 complete(&dm->host_event); 1289 return; 1290 } 1291 /* 1292 * If there are more versions to try, continue 1293 * with negotiations; if not 1294 * shutdown the service since we are not able 1295 * to negotiate a suitable version number 1296 * with the host. 1297 */ 1298 if (dm->next_version == 0) 1299 goto version_error; 1300 1301 memset(&version_req, 0, sizeof(struct dm_version_request)); 1302 version_req.hdr.type = DM_VERSION_REQUEST; 1303 version_req.hdr.size = sizeof(struct dm_version_request); 1304 version_req.hdr.trans_id = atomic_inc_return(&trans_id); 1305 version_req.version.version = dm->next_version; 1306 1307 /* 1308 * Set the next version to try in case current version fails. 1309 * Win7 protocol ought to be the last one to try. 1310 */ 1311 switch (version_req.version.version) { 1312 case DYNMEM_PROTOCOL_VERSION_WIN8: 1313 dm->next_version = DYNMEM_PROTOCOL_VERSION_WIN7; 1314 version_req.is_last_attempt = 0; 1315 break; 1316 default: 1317 dm->next_version = 0; 1318 version_req.is_last_attempt = 1; 1319 } 1320 1321 ret = vmbus_sendpacket(dm->dev->channel, &version_req, 1322 sizeof(struct dm_version_request), 1323 (unsigned long)NULL, 1324 VM_PKT_DATA_INBAND, 0); 1325 1326 if (ret) 1327 goto version_error; 1328 1329 return; 1330 1331 version_error: 1332 dm->state = DM_INIT_ERROR; 1333 complete(&dm->host_event); 1334 } 1335 1336 static void cap_resp(struct hv_dynmem_device *dm, 1337 struct dm_capabilities_resp_msg *cap_resp) 1338 { 1339 if (!cap_resp->is_accepted) { 1340 pr_info("Capabilities not accepted by host\n"); 1341 dm->state = DM_INIT_ERROR; 1342 } 1343 complete(&dm->host_event); 1344 } 1345 1346 static void balloon_onchannelcallback(void *context) 1347 { 1348 struct hv_device *dev = context; 1349 u32 recvlen; 1350 u64 requestid; 1351 struct dm_message *dm_msg; 1352 struct dm_header *dm_hdr; 1353 struct hv_dynmem_device *dm = hv_get_drvdata(dev); 1354 struct dm_balloon *bal_msg; 1355 struct dm_hot_add *ha_msg; 1356 union dm_mem_page_range *ha_pg_range; 1357 union dm_mem_page_range *ha_region; 1358 1359 memset(recv_buffer, 0, sizeof(recv_buffer)); 1360 vmbus_recvpacket(dev->channel, recv_buffer, 1361 PAGE_SIZE, &recvlen, &requestid); 1362 1363 if (recvlen > 0) { 1364 dm_msg = (struct dm_message *)recv_buffer; 1365 dm_hdr = &dm_msg->hdr; 1366 1367 switch (dm_hdr->type) { 1368 case DM_VERSION_RESPONSE: 1369 version_resp(dm, 1370 (struct dm_version_response *)dm_msg); 1371 break; 1372 1373 case DM_CAPABILITIES_RESPONSE: 1374 cap_resp(dm, 1375 (struct dm_capabilities_resp_msg *)dm_msg); 1376 break; 1377 1378 case DM_BALLOON_REQUEST: 1379 if (dm->state == DM_BALLOON_UP) 1380 pr_warn("Currently ballooning\n"); 1381 bal_msg = (struct dm_balloon *)recv_buffer; 1382 dm->state = DM_BALLOON_UP; 1383 dm_device.balloon_wrk.num_pages = bal_msg->num_pages; 1384 schedule_work(&dm_device.balloon_wrk.wrk); 1385 break; 1386 1387 case DM_UNBALLOON_REQUEST: 1388 dm->state = DM_BALLOON_DOWN; 1389 balloon_down(dm, 1390 (struct dm_unballoon_request *)recv_buffer); 1391 break; 1392 1393 case DM_MEM_HOT_ADD_REQUEST: 1394 if (dm->state == DM_HOT_ADD) 1395 pr_warn("Currently hot-adding\n"); 1396 dm->state = DM_HOT_ADD; 1397 ha_msg = (struct dm_hot_add *)recv_buffer; 1398 if (ha_msg->hdr.size == sizeof(struct dm_hot_add)) { 1399 /* 1400 * This is a normal hot-add request specifying 1401 * hot-add memory. 1402 */ 1403 ha_pg_range = &ha_msg->range; 1404 dm->ha_wrk.ha_page_range = *ha_pg_range; 1405 dm->ha_wrk.ha_region_range.page_range = 0; 1406 } else { 1407 /* 1408 * Host is specifying that we first hot-add 1409 * a region and then partially populate this 1410 * region. 1411 */ 1412 dm->host_specified_ha_region = true; 1413 ha_pg_range = &ha_msg->range; 1414 ha_region = &ha_pg_range[1]; 1415 dm->ha_wrk.ha_page_range = *ha_pg_range; 1416 dm->ha_wrk.ha_region_range = *ha_region; 1417 } 1418 schedule_work(&dm_device.ha_wrk.wrk); 1419 break; 1420 1421 case DM_INFO_MESSAGE: 1422 process_info(dm, (struct dm_info_msg *)dm_msg); 1423 break; 1424 1425 default: 1426 pr_err("Unhandled message: type: %d\n", dm_hdr->type); 1427 1428 } 1429 } 1430 1431 } 1432 1433 static int balloon_probe(struct hv_device *dev, 1434 const struct hv_vmbus_device_id *dev_id) 1435 { 1436 int ret; 1437 unsigned long t; 1438 struct dm_version_request version_req; 1439 struct dm_capabilities cap_msg; 1440 1441 do_hot_add = hot_add; 1442 1443 /* 1444 * First allocate a send buffer. 1445 */ 1446 1447 send_buffer = kmalloc(PAGE_SIZE, GFP_KERNEL); 1448 if (!send_buffer) 1449 return -ENOMEM; 1450 1451 ret = vmbus_open(dev->channel, dm_ring_size, dm_ring_size, NULL, 0, 1452 balloon_onchannelcallback, dev); 1453 1454 if (ret) 1455 goto probe_error0; 1456 1457 dm_device.dev = dev; 1458 dm_device.state = DM_INITIALIZING; 1459 dm_device.next_version = DYNMEM_PROTOCOL_VERSION_WIN8; 1460 init_completion(&dm_device.host_event); 1461 init_completion(&dm_device.config_event); 1462 INIT_LIST_HEAD(&dm_device.ha_region_list); 1463 mutex_init(&dm_device.ha_region_mutex); 1464 INIT_WORK(&dm_device.balloon_wrk.wrk, balloon_up); 1465 INIT_WORK(&dm_device.ha_wrk.wrk, hot_add_req); 1466 dm_device.host_specified_ha_region = false; 1467 1468 dm_device.thread = 1469 kthread_run(dm_thread_func, &dm_device, "hv_balloon"); 1470 if (IS_ERR(dm_device.thread)) { 1471 ret = PTR_ERR(dm_device.thread); 1472 goto probe_error1; 1473 } 1474 1475 #ifdef CONFIG_MEMORY_HOTPLUG 1476 set_online_page_callback(&hv_online_page); 1477 register_memory_notifier(&hv_memory_nb); 1478 #endif 1479 1480 hv_set_drvdata(dev, &dm_device); 1481 /* 1482 * Initiate the hand shake with the host and negotiate 1483 * a version that the host can support. We start with the 1484 * highest version number and go down if the host cannot 1485 * support it. 1486 */ 1487 memset(&version_req, 0, sizeof(struct dm_version_request)); 1488 version_req.hdr.type = DM_VERSION_REQUEST; 1489 version_req.hdr.size = sizeof(struct dm_version_request); 1490 version_req.hdr.trans_id = atomic_inc_return(&trans_id); 1491 version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN10; 1492 version_req.is_last_attempt = 0; 1493 1494 ret = vmbus_sendpacket(dev->channel, &version_req, 1495 sizeof(struct dm_version_request), 1496 (unsigned long)NULL, 1497 VM_PKT_DATA_INBAND, 0); 1498 if (ret) 1499 goto probe_error2; 1500 1501 t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ); 1502 if (t == 0) { 1503 ret = -ETIMEDOUT; 1504 goto probe_error2; 1505 } 1506 1507 /* 1508 * If we could not negotiate a compatible version with the host 1509 * fail the probe function. 1510 */ 1511 if (dm_device.state == DM_INIT_ERROR) { 1512 ret = -ETIMEDOUT; 1513 goto probe_error2; 1514 } 1515 /* 1516 * Now submit our capabilities to the host. 1517 */ 1518 memset(&cap_msg, 0, sizeof(struct dm_capabilities)); 1519 cap_msg.hdr.type = DM_CAPABILITIES_REPORT; 1520 cap_msg.hdr.size = sizeof(struct dm_capabilities); 1521 cap_msg.hdr.trans_id = atomic_inc_return(&trans_id); 1522 1523 cap_msg.caps.cap_bits.balloon = 1; 1524 cap_msg.caps.cap_bits.hot_add = 1; 1525 1526 /* 1527 * Specify our alignment requirements as it relates 1528 * memory hot-add. Specify 128MB alignment. 1529 */ 1530 cap_msg.caps.cap_bits.hot_add_alignment = 7; 1531 1532 /* 1533 * Currently the host does not use these 1534 * values and we set them to what is done in the 1535 * Windows driver. 1536 */ 1537 cap_msg.min_page_cnt = 0; 1538 cap_msg.max_page_number = -1; 1539 1540 ret = vmbus_sendpacket(dev->channel, &cap_msg, 1541 sizeof(struct dm_capabilities), 1542 (unsigned long)NULL, 1543 VM_PKT_DATA_INBAND, 0); 1544 if (ret) 1545 goto probe_error2; 1546 1547 t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ); 1548 if (t == 0) { 1549 ret = -ETIMEDOUT; 1550 goto probe_error2; 1551 } 1552 1553 /* 1554 * If the host does not like our capabilities, 1555 * fail the probe function. 1556 */ 1557 if (dm_device.state == DM_INIT_ERROR) { 1558 ret = -ETIMEDOUT; 1559 goto probe_error2; 1560 } 1561 1562 dm_device.state = DM_INITIALIZED; 1563 1564 return 0; 1565 1566 probe_error2: 1567 #ifdef CONFIG_MEMORY_HOTPLUG 1568 restore_online_page_callback(&hv_online_page); 1569 #endif 1570 kthread_stop(dm_device.thread); 1571 1572 probe_error1: 1573 vmbus_close(dev->channel); 1574 probe_error0: 1575 kfree(send_buffer); 1576 return ret; 1577 } 1578 1579 static int balloon_remove(struct hv_device *dev) 1580 { 1581 struct hv_dynmem_device *dm = hv_get_drvdata(dev); 1582 struct list_head *cur, *tmp; 1583 struct hv_hotadd_state *has; 1584 1585 if (dm->num_pages_ballooned != 0) 1586 pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned); 1587 1588 cancel_work_sync(&dm->balloon_wrk.wrk); 1589 cancel_work_sync(&dm->ha_wrk.wrk); 1590 1591 vmbus_close(dev->channel); 1592 kthread_stop(dm->thread); 1593 kfree(send_buffer); 1594 #ifdef CONFIG_MEMORY_HOTPLUG 1595 restore_online_page_callback(&hv_online_page); 1596 unregister_memory_notifier(&hv_memory_nb); 1597 #endif 1598 list_for_each_safe(cur, tmp, &dm->ha_region_list) { 1599 has = list_entry(cur, struct hv_hotadd_state, list); 1600 list_del(&has->list); 1601 kfree(has); 1602 } 1603 1604 return 0; 1605 } 1606 1607 static const struct hv_vmbus_device_id id_table[] = { 1608 /* Dynamic Memory Class ID */ 1609 /* 525074DC-8985-46e2-8057-A307DC18A502 */ 1610 { HV_DM_GUID, }, 1611 { }, 1612 }; 1613 1614 MODULE_DEVICE_TABLE(vmbus, id_table); 1615 1616 static struct hv_driver balloon_drv = { 1617 .name = "hv_balloon", 1618 .id_table = id_table, 1619 .probe = balloon_probe, 1620 .remove = balloon_remove, 1621 }; 1622 1623 static int __init init_balloon_drv(void) 1624 { 1625 1626 return vmbus_driver_register(&balloon_drv); 1627 } 1628 1629 module_init(init_balloon_drv); 1630 1631 MODULE_DESCRIPTION("Hyper-V Balloon"); 1632 MODULE_LICENSE("GPL"); 1633