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 66 DYNMEM_PROTOCOL_VERSION_WIN7 = DYNMEM_PROTOCOL_VERSION_1, 67 DYNMEM_PROTOCOL_VERSION_WIN8 = DYNMEM_PROTOCOL_VERSION_2, 68 69 DYNMEM_PROTOCOL_VERSION_CURRENT = DYNMEM_PROTOCOL_VERSION_WIN8 70 }; 71 72 73 74 /* 75 * Message Types 76 */ 77 78 enum dm_message_type { 79 /* 80 * Version 0.3 81 */ 82 DM_ERROR = 0, 83 DM_VERSION_REQUEST = 1, 84 DM_VERSION_RESPONSE = 2, 85 DM_CAPABILITIES_REPORT = 3, 86 DM_CAPABILITIES_RESPONSE = 4, 87 DM_STATUS_REPORT = 5, 88 DM_BALLOON_REQUEST = 6, 89 DM_BALLOON_RESPONSE = 7, 90 DM_UNBALLOON_REQUEST = 8, 91 DM_UNBALLOON_RESPONSE = 9, 92 DM_MEM_HOT_ADD_REQUEST = 10, 93 DM_MEM_HOT_ADD_RESPONSE = 11, 94 DM_VERSION_03_MAX = 11, 95 /* 96 * Version 1.0. 97 */ 98 DM_INFO_MESSAGE = 12, 99 DM_VERSION_1_MAX = 12 100 }; 101 102 103 /* 104 * Structures defining the dynamic memory management 105 * protocol. 106 */ 107 108 union dm_version { 109 struct { 110 __u16 minor_version; 111 __u16 major_version; 112 }; 113 __u32 version; 114 } __packed; 115 116 117 union dm_caps { 118 struct { 119 __u64 balloon:1; 120 __u64 hot_add:1; 121 /* 122 * To support guests that may have alignment 123 * limitations on hot-add, the guest can specify 124 * its alignment requirements; a value of n 125 * represents an alignment of 2^n in mega bytes. 126 */ 127 __u64 hot_add_alignment:4; 128 __u64 reservedz:58; 129 } cap_bits; 130 __u64 caps; 131 } __packed; 132 133 union dm_mem_page_range { 134 struct { 135 /* 136 * The PFN number of the first page in the range. 137 * 40 bits is the architectural limit of a PFN 138 * number for AMD64. 139 */ 140 __u64 start_page:40; 141 /* 142 * The number of pages in the range. 143 */ 144 __u64 page_cnt:24; 145 } finfo; 146 __u64 page_range; 147 } __packed; 148 149 150 151 /* 152 * The header for all dynamic memory messages: 153 * 154 * type: Type of the message. 155 * size: Size of the message in bytes; including the header. 156 * trans_id: The guest is responsible for manufacturing this ID. 157 */ 158 159 struct dm_header { 160 __u16 type; 161 __u16 size; 162 __u32 trans_id; 163 } __packed; 164 165 /* 166 * A generic message format for dynamic memory. 167 * Specific message formats are defined later in the file. 168 */ 169 170 struct dm_message { 171 struct dm_header hdr; 172 __u8 data[]; /* enclosed message */ 173 } __packed; 174 175 176 /* 177 * Specific message types supporting the dynamic memory protocol. 178 */ 179 180 /* 181 * Version negotiation message. Sent from the guest to the host. 182 * The guest is free to try different versions until the host 183 * accepts the version. 184 * 185 * dm_version: The protocol version requested. 186 * is_last_attempt: If TRUE, this is the last version guest will request. 187 * reservedz: Reserved field, set to zero. 188 */ 189 190 struct dm_version_request { 191 struct dm_header hdr; 192 union dm_version version; 193 __u32 is_last_attempt:1; 194 __u32 reservedz:31; 195 } __packed; 196 197 /* 198 * Version response message; Host to Guest and indicates 199 * if the host has accepted the version sent by the guest. 200 * 201 * is_accepted: If TRUE, host has accepted the version and the guest 202 * should proceed to the next stage of the protocol. FALSE indicates that 203 * guest should re-try with a different version. 204 * 205 * reservedz: Reserved field, set to zero. 206 */ 207 208 struct dm_version_response { 209 struct dm_header hdr; 210 __u64 is_accepted:1; 211 __u64 reservedz:63; 212 } __packed; 213 214 /* 215 * Message reporting capabilities. This is sent from the guest to the 216 * host. 217 */ 218 219 struct dm_capabilities { 220 struct dm_header hdr; 221 union dm_caps caps; 222 __u64 min_page_cnt; 223 __u64 max_page_number; 224 } __packed; 225 226 /* 227 * Response to the capabilities message. This is sent from the host to the 228 * guest. This message notifies if the host has accepted the guest's 229 * capabilities. If the host has not accepted, the guest must shutdown 230 * the service. 231 * 232 * is_accepted: Indicates if the host has accepted guest's capabilities. 233 * reservedz: Must be 0. 234 */ 235 236 struct dm_capabilities_resp_msg { 237 struct dm_header hdr; 238 __u64 is_accepted:1; 239 __u64 reservedz:63; 240 } __packed; 241 242 /* 243 * This message is used to report memory pressure from the guest. 244 * This message is not part of any transaction and there is no 245 * response to this message. 246 * 247 * num_avail: Available memory in pages. 248 * num_committed: Committed memory in pages. 249 * page_file_size: The accumulated size of all page files 250 * in the system in pages. 251 * zero_free: The nunber of zero and free pages. 252 * page_file_writes: The writes to the page file in pages. 253 * io_diff: An indicator of file cache efficiency or page file activity, 254 * calculated as File Cache Page Fault Count - Page Read Count. 255 * This value is in pages. 256 * 257 * Some of these metrics are Windows specific and fortunately 258 * the algorithm on the host side that computes the guest memory 259 * pressure only uses num_committed value. 260 */ 261 262 struct dm_status { 263 struct dm_header hdr; 264 __u64 num_avail; 265 __u64 num_committed; 266 __u64 page_file_size; 267 __u64 zero_free; 268 __u32 page_file_writes; 269 __u32 io_diff; 270 } __packed; 271 272 273 /* 274 * Message to ask the guest to allocate memory - balloon up message. 275 * This message is sent from the host to the guest. The guest may not be 276 * able to allocate as much memory as requested. 277 * 278 * num_pages: number of pages to allocate. 279 */ 280 281 struct dm_balloon { 282 struct dm_header hdr; 283 __u32 num_pages; 284 __u32 reservedz; 285 } __packed; 286 287 288 /* 289 * Balloon response message; this message is sent from the guest 290 * to the host in response to the balloon message. 291 * 292 * reservedz: Reserved; must be set to zero. 293 * more_pages: If FALSE, this is the last message of the transaction. 294 * if TRUE there will atleast one more message from the guest. 295 * 296 * range_count: The number of ranges in the range array. 297 * 298 * range_array: An array of page ranges returned to the host. 299 * 300 */ 301 302 struct dm_balloon_response { 303 struct dm_header hdr; 304 __u32 reservedz; 305 __u32 more_pages:1; 306 __u32 range_count:31; 307 union dm_mem_page_range range_array[]; 308 } __packed; 309 310 /* 311 * Un-balloon message; this message is sent from the host 312 * to the guest to give guest more memory. 313 * 314 * more_pages: If FALSE, this is the last message of the transaction. 315 * if TRUE there will atleast one more message from the guest. 316 * 317 * reservedz: Reserved; must be set to zero. 318 * 319 * range_count: The number of ranges in the range array. 320 * 321 * range_array: An array of page ranges returned to the host. 322 * 323 */ 324 325 struct dm_unballoon_request { 326 struct dm_header hdr; 327 __u32 more_pages:1; 328 __u32 reservedz:31; 329 __u32 range_count; 330 union dm_mem_page_range range_array[]; 331 } __packed; 332 333 /* 334 * Un-balloon response message; this message is sent from the guest 335 * to the host in response to an unballoon request. 336 * 337 */ 338 339 struct dm_unballoon_response { 340 struct dm_header hdr; 341 } __packed; 342 343 344 /* 345 * Hot add request message. Message sent from the host to the guest. 346 * 347 * mem_range: Memory range to hot add. 348 * 349 * On Linux we currently don't support this since we cannot hot add 350 * arbitrary granularity of memory. 351 */ 352 353 struct dm_hot_add { 354 struct dm_header hdr; 355 union dm_mem_page_range range; 356 } __packed; 357 358 /* 359 * Hot add response message. 360 * This message is sent by the guest to report the status of a hot add request. 361 * If page_count is less than the requested page count, then the host should 362 * assume all further hot add requests will fail, since this indicates that 363 * the guest has hit an upper physical memory barrier. 364 * 365 * Hot adds may also fail due to low resources; in this case, the guest must 366 * not complete this message until the hot add can succeed, and the host must 367 * not send a new hot add request until the response is sent. 368 * If VSC fails to hot add memory DYNMEM_NUMBER_OF_UNSUCCESSFUL_HOTADD_ATTEMPTS 369 * times it fails the request. 370 * 371 * 372 * page_count: number of pages that were successfully hot added. 373 * 374 * result: result of the operation 1: success, 0: failure. 375 * 376 */ 377 378 struct dm_hot_add_response { 379 struct dm_header hdr; 380 __u32 page_count; 381 __u32 result; 382 } __packed; 383 384 /* 385 * Types of information sent from host to the guest. 386 */ 387 388 enum dm_info_type { 389 INFO_TYPE_MAX_PAGE_CNT = 0, 390 MAX_INFO_TYPE 391 }; 392 393 394 /* 395 * Header for the information message. 396 */ 397 398 struct dm_info_header { 399 enum dm_info_type type; 400 __u32 data_size; 401 } __packed; 402 403 /* 404 * This message is sent from the host to the guest to pass 405 * some relevant information (win8 addition). 406 * 407 * reserved: no used. 408 * info_size: size of the information blob. 409 * info: information blob. 410 */ 411 412 struct dm_info_msg { 413 struct dm_header hdr; 414 __u32 reserved; 415 __u32 info_size; 416 __u8 info[]; 417 }; 418 419 /* 420 * End protocol definitions. 421 */ 422 423 /* 424 * State to manage hot adding memory into the guest. 425 * The range start_pfn : end_pfn specifies the range 426 * that the host has asked us to hot add. The range 427 * start_pfn : ha_end_pfn specifies the range that we have 428 * currently hot added. We hot add in multiples of 128M 429 * chunks; it is possible that we may not be able to bring 430 * online all the pages in the region. The range 431 * covered_start_pfn : covered_end_pfn defines the pages that can 432 * be brough online. 433 */ 434 435 struct hv_hotadd_state { 436 struct list_head list; 437 unsigned long start_pfn; 438 unsigned long covered_start_pfn; 439 unsigned long covered_end_pfn; 440 unsigned long ha_end_pfn; 441 unsigned long end_pfn; 442 }; 443 444 struct balloon_state { 445 __u32 num_pages; 446 struct work_struct wrk; 447 }; 448 449 struct hot_add_wrk { 450 union dm_mem_page_range ha_page_range; 451 union dm_mem_page_range ha_region_range; 452 struct work_struct wrk; 453 }; 454 455 static bool hot_add = true; 456 static bool do_hot_add; 457 /* 458 * Delay reporting memory pressure by 459 * the specified number of seconds. 460 */ 461 static uint pressure_report_delay = 45; 462 463 /* 464 * The last time we posted a pressure report to host. 465 */ 466 static unsigned long last_post_time; 467 468 module_param(hot_add, bool, (S_IRUGO | S_IWUSR)); 469 MODULE_PARM_DESC(hot_add, "If set attempt memory hot_add"); 470 471 module_param(pressure_report_delay, uint, (S_IRUGO | S_IWUSR)); 472 MODULE_PARM_DESC(pressure_report_delay, "Delay in secs in reporting pressure"); 473 static atomic_t trans_id = ATOMIC_INIT(0); 474 475 static int dm_ring_size = (5 * PAGE_SIZE); 476 477 /* 478 * Driver specific state. 479 */ 480 481 enum hv_dm_state { 482 DM_INITIALIZING = 0, 483 DM_INITIALIZED, 484 DM_BALLOON_UP, 485 DM_BALLOON_DOWN, 486 DM_HOT_ADD, 487 DM_INIT_ERROR 488 }; 489 490 491 static __u8 recv_buffer[PAGE_SIZE]; 492 static __u8 *send_buffer; 493 #define PAGES_IN_2M 512 494 #define HA_CHUNK (32 * 1024) 495 496 struct hv_dynmem_device { 497 struct hv_device *dev; 498 enum hv_dm_state state; 499 struct completion host_event; 500 struct completion config_event; 501 502 /* 503 * Number of pages we have currently ballooned out. 504 */ 505 unsigned int num_pages_ballooned; 506 507 /* 508 * State to manage the ballooning (up) operation. 509 */ 510 struct balloon_state balloon_wrk; 511 512 /* 513 * State to execute the "hot-add" operation. 514 */ 515 struct hot_add_wrk ha_wrk; 516 517 /* 518 * This state tracks if the host has specified a hot-add 519 * region. 520 */ 521 bool host_specified_ha_region; 522 523 /* 524 * State to synchronize hot-add. 525 */ 526 struct completion ol_waitevent; 527 bool ha_waiting; 528 /* 529 * This thread handles hot-add 530 * requests from the host as well as notifying 531 * the host with regards to memory pressure in 532 * the guest. 533 */ 534 struct task_struct *thread; 535 536 /* 537 * A list of hot-add regions. 538 */ 539 struct list_head ha_region_list; 540 541 /* 542 * We start with the highest version we can support 543 * and downgrade based on the host; we save here the 544 * next version to try. 545 */ 546 __u32 next_version; 547 }; 548 549 static struct hv_dynmem_device dm_device; 550 551 static void post_status(struct hv_dynmem_device *dm); 552 #ifdef CONFIG_MEMORY_HOTPLUG 553 554 static void hv_bring_pgs_online(unsigned long start_pfn, unsigned long size) 555 { 556 int i; 557 558 for (i = 0; i < size; i++) { 559 struct page *pg; 560 pg = pfn_to_page(start_pfn + i); 561 __online_page_set_limits(pg); 562 __online_page_increment_counters(pg); 563 __online_page_free(pg); 564 } 565 } 566 567 static void hv_mem_hot_add(unsigned long start, unsigned long size, 568 unsigned long pfn_count, 569 struct hv_hotadd_state *has) 570 { 571 int ret = 0; 572 int i, nid; 573 unsigned long start_pfn; 574 unsigned long processed_pfn; 575 unsigned long total_pfn = pfn_count; 576 577 for (i = 0; i < (size/HA_CHUNK); i++) { 578 start_pfn = start + (i * HA_CHUNK); 579 has->ha_end_pfn += HA_CHUNK; 580 581 if (total_pfn > HA_CHUNK) { 582 processed_pfn = HA_CHUNK; 583 total_pfn -= HA_CHUNK; 584 } else { 585 processed_pfn = total_pfn; 586 total_pfn = 0; 587 } 588 589 has->covered_end_pfn += processed_pfn; 590 591 init_completion(&dm_device.ol_waitevent); 592 dm_device.ha_waiting = true; 593 594 nid = memory_add_physaddr_to_nid(PFN_PHYS(start_pfn)); 595 ret = add_memory(nid, PFN_PHYS((start_pfn)), 596 (HA_CHUNK << PAGE_SHIFT)); 597 598 if (ret) { 599 pr_info("hot_add memory failed error is %d\n", ret); 600 if (ret == -EEXIST) { 601 /* 602 * This error indicates that the error 603 * is not a transient failure. This is the 604 * case where the guest's physical address map 605 * precludes hot adding memory. Stop all further 606 * memory hot-add. 607 */ 608 do_hot_add = false; 609 } 610 has->ha_end_pfn -= HA_CHUNK; 611 has->covered_end_pfn -= processed_pfn; 612 break; 613 } 614 615 /* 616 * Wait for the memory block to be onlined. 617 * Since the hot add has succeeded, it is ok to 618 * proceed even if the pages in the hot added region 619 * have not been "onlined" within the allowed time. 620 */ 621 wait_for_completion_timeout(&dm_device.ol_waitevent, 5*HZ); 622 post_status(&dm_device); 623 } 624 625 return; 626 } 627 628 static void hv_online_page(struct page *pg) 629 { 630 struct list_head *cur; 631 struct hv_hotadd_state *has; 632 unsigned long cur_start_pgp; 633 unsigned long cur_end_pgp; 634 635 if (dm_device.ha_waiting) { 636 dm_device.ha_waiting = false; 637 complete(&dm_device.ol_waitevent); 638 } 639 640 list_for_each(cur, &dm_device.ha_region_list) { 641 has = list_entry(cur, struct hv_hotadd_state, list); 642 cur_start_pgp = (unsigned long) 643 pfn_to_page(has->covered_start_pfn); 644 cur_end_pgp = (unsigned long)pfn_to_page(has->covered_end_pfn); 645 646 if (((unsigned long)pg >= cur_start_pgp) && 647 ((unsigned long)pg < cur_end_pgp)) { 648 /* 649 * This frame is currently backed; online the 650 * page. 651 */ 652 __online_page_set_limits(pg); 653 __online_page_increment_counters(pg); 654 __online_page_free(pg); 655 has->covered_start_pfn++; 656 } 657 } 658 } 659 660 static bool pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt) 661 { 662 struct list_head *cur; 663 struct hv_hotadd_state *has; 664 unsigned long residual, new_inc; 665 666 if (list_empty(&dm_device.ha_region_list)) 667 return false; 668 669 list_for_each(cur, &dm_device.ha_region_list) { 670 has = list_entry(cur, struct hv_hotadd_state, list); 671 672 /* 673 * If the pfn range we are dealing with is not in the current 674 * "hot add block", move on. 675 */ 676 if ((start_pfn >= has->end_pfn)) 677 continue; 678 /* 679 * If the current hot add-request extends beyond 680 * our current limit; extend it. 681 */ 682 if ((start_pfn + pfn_cnt) > has->end_pfn) { 683 residual = (start_pfn + pfn_cnt - has->end_pfn); 684 /* 685 * Extend the region by multiples of HA_CHUNK. 686 */ 687 new_inc = (residual / HA_CHUNK) * HA_CHUNK; 688 if (residual % HA_CHUNK) 689 new_inc += HA_CHUNK; 690 691 has->end_pfn += new_inc; 692 } 693 694 /* 695 * If the current start pfn is not where the covered_end 696 * is, update it. 697 */ 698 699 if (has->covered_end_pfn != start_pfn) { 700 has->covered_end_pfn = start_pfn; 701 has->covered_start_pfn = start_pfn; 702 } 703 return true; 704 705 } 706 707 return false; 708 } 709 710 static unsigned long handle_pg_range(unsigned long pg_start, 711 unsigned long pg_count) 712 { 713 unsigned long start_pfn = pg_start; 714 unsigned long pfn_cnt = pg_count; 715 unsigned long size; 716 struct list_head *cur; 717 struct hv_hotadd_state *has; 718 unsigned long pgs_ol = 0; 719 unsigned long old_covered_state; 720 721 if (list_empty(&dm_device.ha_region_list)) 722 return 0; 723 724 list_for_each(cur, &dm_device.ha_region_list) { 725 has = list_entry(cur, struct hv_hotadd_state, list); 726 727 /* 728 * If the pfn range we are dealing with is not in the current 729 * "hot add block", move on. 730 */ 731 if ((start_pfn >= has->end_pfn)) 732 continue; 733 734 old_covered_state = has->covered_end_pfn; 735 736 if (start_pfn < has->ha_end_pfn) { 737 /* 738 * This is the case where we are backing pages 739 * in an already hot added region. Bring 740 * these pages online first. 741 */ 742 pgs_ol = has->ha_end_pfn - start_pfn; 743 if (pgs_ol > pfn_cnt) 744 pgs_ol = pfn_cnt; 745 hv_bring_pgs_online(start_pfn, pgs_ol); 746 has->covered_end_pfn += pgs_ol; 747 has->covered_start_pfn += pgs_ol; 748 pfn_cnt -= pgs_ol; 749 } 750 751 if ((has->ha_end_pfn < has->end_pfn) && (pfn_cnt > 0)) { 752 /* 753 * We have some residual hot add range 754 * that needs to be hot added; hot add 755 * it now. Hot add a multiple of 756 * of HA_CHUNK that fully covers the pages 757 * we have. 758 */ 759 size = (has->end_pfn - has->ha_end_pfn); 760 if (pfn_cnt <= size) { 761 size = ((pfn_cnt / HA_CHUNK) * HA_CHUNK); 762 if (pfn_cnt % HA_CHUNK) 763 size += HA_CHUNK; 764 } else { 765 pfn_cnt = size; 766 } 767 hv_mem_hot_add(has->ha_end_pfn, size, pfn_cnt, has); 768 } 769 /* 770 * If we managed to online any pages that were given to us, 771 * we declare success. 772 */ 773 return has->covered_end_pfn - old_covered_state; 774 775 } 776 777 return 0; 778 } 779 780 static unsigned long process_hot_add(unsigned long pg_start, 781 unsigned long pfn_cnt, 782 unsigned long rg_start, 783 unsigned long rg_size) 784 { 785 struct hv_hotadd_state *ha_region = NULL; 786 787 if (pfn_cnt == 0) 788 return 0; 789 790 if (!dm_device.host_specified_ha_region) 791 if (pfn_covered(pg_start, pfn_cnt)) 792 goto do_pg_range; 793 794 /* 795 * If the host has specified a hot-add range; deal with it first. 796 */ 797 798 if (rg_size != 0) { 799 ha_region = kzalloc(sizeof(struct hv_hotadd_state), GFP_KERNEL); 800 if (!ha_region) 801 return 0; 802 803 INIT_LIST_HEAD(&ha_region->list); 804 805 list_add_tail(&ha_region->list, &dm_device.ha_region_list); 806 ha_region->start_pfn = rg_start; 807 ha_region->ha_end_pfn = rg_start; 808 ha_region->covered_start_pfn = pg_start; 809 ha_region->covered_end_pfn = pg_start; 810 ha_region->end_pfn = rg_start + rg_size; 811 } 812 813 do_pg_range: 814 /* 815 * Process the page range specified; bringing them 816 * online if possible. 817 */ 818 return handle_pg_range(pg_start, pfn_cnt); 819 } 820 821 #endif 822 823 static void hot_add_req(struct work_struct *dummy) 824 { 825 struct dm_hot_add_response resp; 826 #ifdef CONFIG_MEMORY_HOTPLUG 827 unsigned long pg_start, pfn_cnt; 828 unsigned long rg_start, rg_sz; 829 #endif 830 struct hv_dynmem_device *dm = &dm_device; 831 832 memset(&resp, 0, sizeof(struct dm_hot_add_response)); 833 resp.hdr.type = DM_MEM_HOT_ADD_RESPONSE; 834 resp.hdr.size = sizeof(struct dm_hot_add_response); 835 836 #ifdef CONFIG_MEMORY_HOTPLUG 837 pg_start = dm->ha_wrk.ha_page_range.finfo.start_page; 838 pfn_cnt = dm->ha_wrk.ha_page_range.finfo.page_cnt; 839 840 rg_start = dm->ha_wrk.ha_region_range.finfo.start_page; 841 rg_sz = dm->ha_wrk.ha_region_range.finfo.page_cnt; 842 843 if ((rg_start == 0) && (!dm->host_specified_ha_region)) { 844 unsigned long region_size; 845 unsigned long region_start; 846 847 /* 848 * The host has not specified the hot-add region. 849 * Based on the hot-add page range being specified, 850 * compute a hot-add region that can cover the pages 851 * that need to be hot-added while ensuring the alignment 852 * and size requirements of Linux as it relates to hot-add. 853 */ 854 region_start = pg_start; 855 region_size = (pfn_cnt / HA_CHUNK) * HA_CHUNK; 856 if (pfn_cnt % HA_CHUNK) 857 region_size += HA_CHUNK; 858 859 region_start = (pg_start / HA_CHUNK) * HA_CHUNK; 860 861 rg_start = region_start; 862 rg_sz = region_size; 863 } 864 865 if (do_hot_add) 866 resp.page_count = process_hot_add(pg_start, pfn_cnt, 867 rg_start, rg_sz); 868 #endif 869 /* 870 * The result field of the response structure has the 871 * following semantics: 872 * 873 * 1. If all or some pages hot-added: Guest should return success. 874 * 875 * 2. If no pages could be hot-added: 876 * 877 * If the guest returns success, then the host 878 * will not attempt any further hot-add operations. This 879 * signifies a permanent failure. 880 * 881 * If the guest returns failure, then this failure will be 882 * treated as a transient failure and the host may retry the 883 * hot-add operation after some delay. 884 */ 885 if (resp.page_count > 0) 886 resp.result = 1; 887 else if (!do_hot_add) 888 resp.result = 1; 889 else 890 resp.result = 0; 891 892 if (!do_hot_add || (resp.page_count == 0)) 893 pr_info("Memory hot add failed\n"); 894 895 dm->state = DM_INITIALIZED; 896 resp.hdr.trans_id = atomic_inc_return(&trans_id); 897 vmbus_sendpacket(dm->dev->channel, &resp, 898 sizeof(struct dm_hot_add_response), 899 (unsigned long)NULL, 900 VM_PKT_DATA_INBAND, 0); 901 } 902 903 static void process_info(struct hv_dynmem_device *dm, struct dm_info_msg *msg) 904 { 905 struct dm_info_header *info_hdr; 906 907 info_hdr = (struct dm_info_header *)msg->info; 908 909 switch (info_hdr->type) { 910 case INFO_TYPE_MAX_PAGE_CNT: 911 pr_info("Received INFO_TYPE_MAX_PAGE_CNT\n"); 912 pr_info("Data Size is %d\n", info_hdr->data_size); 913 break; 914 default: 915 pr_info("Received Unknown type: %d\n", info_hdr->type); 916 } 917 } 918 919 static unsigned long compute_balloon_floor(void) 920 { 921 unsigned long min_pages; 922 #define MB2PAGES(mb) ((mb) << (20 - PAGE_SHIFT)) 923 /* Simple continuous piecewiese linear function: 924 * max MiB -> min MiB gradient 925 * 0 0 926 * 16 16 927 * 32 24 928 * 128 72 (1/2) 929 * 512 168 (1/4) 930 * 2048 360 (1/8) 931 * 8192 552 (1/32) 932 * 32768 1320 933 * 131072 4392 934 */ 935 if (totalram_pages < MB2PAGES(128)) 936 min_pages = MB2PAGES(8) + (totalram_pages >> 1); 937 else if (totalram_pages < MB2PAGES(512)) 938 min_pages = MB2PAGES(40) + (totalram_pages >> 2); 939 else if (totalram_pages < MB2PAGES(2048)) 940 min_pages = MB2PAGES(104) + (totalram_pages >> 3); 941 else 942 min_pages = MB2PAGES(296) + (totalram_pages >> 5); 943 #undef MB2PAGES 944 return min_pages; 945 } 946 947 /* 948 * Post our status as it relates memory pressure to the 949 * host. Host expects the guests to post this status 950 * periodically at 1 second intervals. 951 * 952 * The metrics specified in this protocol are very Windows 953 * specific and so we cook up numbers here to convey our memory 954 * pressure. 955 */ 956 957 static void post_status(struct hv_dynmem_device *dm) 958 { 959 struct dm_status status; 960 struct sysinfo val; 961 unsigned long now = jiffies; 962 unsigned long last_post = last_post_time; 963 964 if (pressure_report_delay > 0) { 965 --pressure_report_delay; 966 return; 967 } 968 969 if (!time_after(now, (last_post_time + HZ))) 970 return; 971 972 si_meminfo(&val); 973 memset(&status, 0, sizeof(struct dm_status)); 974 status.hdr.type = DM_STATUS_REPORT; 975 status.hdr.size = sizeof(struct dm_status); 976 status.hdr.trans_id = atomic_inc_return(&trans_id); 977 978 /* 979 * The host expects the guest to report free memory. 980 * Further, the host expects the pressure information to 981 * include the ballooned out pages. 982 * For a given amount of memory that we are managing, we 983 * need to compute a floor below which we should not balloon. 984 * Compute this and add it to the pressure report. 985 */ 986 status.num_avail = val.freeram; 987 status.num_committed = vm_memory_committed() + 988 dm->num_pages_ballooned + 989 compute_balloon_floor(); 990 991 /* 992 * If our transaction ID is no longer current, just don't 993 * send the status. This can happen if we were interrupted 994 * after we picked our transaction ID. 995 */ 996 if (status.hdr.trans_id != atomic_read(&trans_id)) 997 return; 998 999 /* 1000 * If the last post time that we sampled has changed, 1001 * we have raced, don't post the status. 1002 */ 1003 if (last_post != last_post_time) 1004 return; 1005 1006 last_post_time = jiffies; 1007 vmbus_sendpacket(dm->dev->channel, &status, 1008 sizeof(struct dm_status), 1009 (unsigned long)NULL, 1010 VM_PKT_DATA_INBAND, 0); 1011 1012 } 1013 1014 static void free_balloon_pages(struct hv_dynmem_device *dm, 1015 union dm_mem_page_range *range_array) 1016 { 1017 int num_pages = range_array->finfo.page_cnt; 1018 __u64 start_frame = range_array->finfo.start_page; 1019 struct page *pg; 1020 int i; 1021 1022 for (i = 0; i < num_pages; i++) { 1023 pg = pfn_to_page(i + start_frame); 1024 __free_page(pg); 1025 dm->num_pages_ballooned--; 1026 } 1027 } 1028 1029 1030 1031 static int alloc_balloon_pages(struct hv_dynmem_device *dm, int num_pages, 1032 struct dm_balloon_response *bl_resp, int alloc_unit, 1033 bool *alloc_error) 1034 { 1035 int i = 0; 1036 struct page *pg; 1037 1038 if (num_pages < alloc_unit) 1039 return 0; 1040 1041 for (i = 0; (i * alloc_unit) < num_pages; i++) { 1042 if (bl_resp->hdr.size + sizeof(union dm_mem_page_range) > 1043 PAGE_SIZE) 1044 return i * alloc_unit; 1045 1046 /* 1047 * We execute this code in a thread context. Furthermore, 1048 * we don't want the kernel to try too hard. 1049 */ 1050 pg = alloc_pages(GFP_HIGHUSER | __GFP_NORETRY | 1051 __GFP_NOMEMALLOC | __GFP_NOWARN, 1052 get_order(alloc_unit << PAGE_SHIFT)); 1053 1054 if (!pg) { 1055 *alloc_error = true; 1056 return i * alloc_unit; 1057 } 1058 1059 1060 dm->num_pages_ballooned += alloc_unit; 1061 1062 /* 1063 * If we allocatted 2M pages; split them so we 1064 * can free them in any order we get. 1065 */ 1066 1067 if (alloc_unit != 1) 1068 split_page(pg, get_order(alloc_unit << PAGE_SHIFT)); 1069 1070 bl_resp->range_count++; 1071 bl_resp->range_array[i].finfo.start_page = 1072 page_to_pfn(pg); 1073 bl_resp->range_array[i].finfo.page_cnt = alloc_unit; 1074 bl_resp->hdr.size += sizeof(union dm_mem_page_range); 1075 1076 } 1077 1078 return num_pages; 1079 } 1080 1081 1082 1083 static void balloon_up(struct work_struct *dummy) 1084 { 1085 int num_pages = dm_device.balloon_wrk.num_pages; 1086 int num_ballooned = 0; 1087 struct dm_balloon_response *bl_resp; 1088 int alloc_unit; 1089 int ret; 1090 bool alloc_error = false; 1091 bool done = false; 1092 int i; 1093 1094 1095 /* 1096 * We will attempt 2M allocations. However, if we fail to 1097 * allocate 2M chunks, we will go back to 4k allocations. 1098 */ 1099 alloc_unit = 512; 1100 1101 while (!done) { 1102 bl_resp = (struct dm_balloon_response *)send_buffer; 1103 memset(send_buffer, 0, PAGE_SIZE); 1104 bl_resp->hdr.type = DM_BALLOON_RESPONSE; 1105 bl_resp->hdr.size = sizeof(struct dm_balloon_response); 1106 bl_resp->more_pages = 1; 1107 1108 1109 num_pages -= num_ballooned; 1110 num_ballooned = alloc_balloon_pages(&dm_device, num_pages, 1111 bl_resp, alloc_unit, 1112 &alloc_error); 1113 1114 if ((alloc_error) && (alloc_unit != 1)) { 1115 alloc_unit = 1; 1116 continue; 1117 } 1118 1119 if ((alloc_error) || (num_ballooned == num_pages)) { 1120 bl_resp->more_pages = 0; 1121 done = true; 1122 dm_device.state = DM_INITIALIZED; 1123 } 1124 1125 /* 1126 * We are pushing a lot of data through the channel; 1127 * deal with transient failures caused because of the 1128 * lack of space in the ring buffer. 1129 */ 1130 1131 do { 1132 bl_resp->hdr.trans_id = atomic_inc_return(&trans_id); 1133 ret = vmbus_sendpacket(dm_device.dev->channel, 1134 bl_resp, 1135 bl_resp->hdr.size, 1136 (unsigned long)NULL, 1137 VM_PKT_DATA_INBAND, 0); 1138 1139 if (ret == -EAGAIN) 1140 msleep(20); 1141 post_status(&dm_device); 1142 } while (ret == -EAGAIN); 1143 1144 if (ret) { 1145 /* 1146 * Free up the memory we allocatted. 1147 */ 1148 pr_info("Balloon response failed\n"); 1149 1150 for (i = 0; i < bl_resp->range_count; i++) 1151 free_balloon_pages(&dm_device, 1152 &bl_resp->range_array[i]); 1153 1154 done = true; 1155 } 1156 } 1157 1158 } 1159 1160 static void balloon_down(struct hv_dynmem_device *dm, 1161 struct dm_unballoon_request *req) 1162 { 1163 union dm_mem_page_range *range_array = req->range_array; 1164 int range_count = req->range_count; 1165 struct dm_unballoon_response resp; 1166 int i; 1167 1168 for (i = 0; i < range_count; i++) { 1169 free_balloon_pages(dm, &range_array[i]); 1170 post_status(&dm_device); 1171 } 1172 1173 if (req->more_pages == 1) 1174 return; 1175 1176 memset(&resp, 0, sizeof(struct dm_unballoon_response)); 1177 resp.hdr.type = DM_UNBALLOON_RESPONSE; 1178 resp.hdr.trans_id = atomic_inc_return(&trans_id); 1179 resp.hdr.size = sizeof(struct dm_unballoon_response); 1180 1181 vmbus_sendpacket(dm_device.dev->channel, &resp, 1182 sizeof(struct dm_unballoon_response), 1183 (unsigned long)NULL, 1184 VM_PKT_DATA_INBAND, 0); 1185 1186 dm->state = DM_INITIALIZED; 1187 } 1188 1189 static void balloon_onchannelcallback(void *context); 1190 1191 static int dm_thread_func(void *dm_dev) 1192 { 1193 struct hv_dynmem_device *dm = dm_dev; 1194 int t; 1195 1196 while (!kthread_should_stop()) { 1197 t = wait_for_completion_interruptible_timeout( 1198 &dm_device.config_event, 1*HZ); 1199 /* 1200 * The host expects us to post information on the memory 1201 * pressure every second. 1202 */ 1203 1204 if (t == 0) 1205 post_status(dm); 1206 1207 } 1208 1209 return 0; 1210 } 1211 1212 1213 static void version_resp(struct hv_dynmem_device *dm, 1214 struct dm_version_response *vresp) 1215 { 1216 struct dm_version_request version_req; 1217 int ret; 1218 1219 if (vresp->is_accepted) { 1220 /* 1221 * We are done; wakeup the 1222 * context waiting for version 1223 * negotiation. 1224 */ 1225 complete(&dm->host_event); 1226 return; 1227 } 1228 /* 1229 * If there are more versions to try, continue 1230 * with negotiations; if not 1231 * shutdown the service since we are not able 1232 * to negotiate a suitable version number 1233 * with the host. 1234 */ 1235 if (dm->next_version == 0) 1236 goto version_error; 1237 1238 dm->next_version = 0; 1239 memset(&version_req, 0, sizeof(struct dm_version_request)); 1240 version_req.hdr.type = DM_VERSION_REQUEST; 1241 version_req.hdr.size = sizeof(struct dm_version_request); 1242 version_req.hdr.trans_id = atomic_inc_return(&trans_id); 1243 version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN7; 1244 version_req.is_last_attempt = 1; 1245 1246 ret = vmbus_sendpacket(dm->dev->channel, &version_req, 1247 sizeof(struct dm_version_request), 1248 (unsigned long)NULL, 1249 VM_PKT_DATA_INBAND, 0); 1250 1251 if (ret) 1252 goto version_error; 1253 1254 return; 1255 1256 version_error: 1257 dm->state = DM_INIT_ERROR; 1258 complete(&dm->host_event); 1259 } 1260 1261 static void cap_resp(struct hv_dynmem_device *dm, 1262 struct dm_capabilities_resp_msg *cap_resp) 1263 { 1264 if (!cap_resp->is_accepted) { 1265 pr_info("Capabilities not accepted by host\n"); 1266 dm->state = DM_INIT_ERROR; 1267 } 1268 complete(&dm->host_event); 1269 } 1270 1271 static void balloon_onchannelcallback(void *context) 1272 { 1273 struct hv_device *dev = context; 1274 u32 recvlen; 1275 u64 requestid; 1276 struct dm_message *dm_msg; 1277 struct dm_header *dm_hdr; 1278 struct hv_dynmem_device *dm = hv_get_drvdata(dev); 1279 struct dm_balloon *bal_msg; 1280 struct dm_hot_add *ha_msg; 1281 union dm_mem_page_range *ha_pg_range; 1282 union dm_mem_page_range *ha_region; 1283 1284 memset(recv_buffer, 0, sizeof(recv_buffer)); 1285 vmbus_recvpacket(dev->channel, recv_buffer, 1286 PAGE_SIZE, &recvlen, &requestid); 1287 1288 if (recvlen > 0) { 1289 dm_msg = (struct dm_message *)recv_buffer; 1290 dm_hdr = &dm_msg->hdr; 1291 1292 switch (dm_hdr->type) { 1293 case DM_VERSION_RESPONSE: 1294 version_resp(dm, 1295 (struct dm_version_response *)dm_msg); 1296 break; 1297 1298 case DM_CAPABILITIES_RESPONSE: 1299 cap_resp(dm, 1300 (struct dm_capabilities_resp_msg *)dm_msg); 1301 break; 1302 1303 case DM_BALLOON_REQUEST: 1304 if (dm->state == DM_BALLOON_UP) 1305 pr_warn("Currently ballooning\n"); 1306 bal_msg = (struct dm_balloon *)recv_buffer; 1307 dm->state = DM_BALLOON_UP; 1308 dm_device.balloon_wrk.num_pages = bal_msg->num_pages; 1309 schedule_work(&dm_device.balloon_wrk.wrk); 1310 break; 1311 1312 case DM_UNBALLOON_REQUEST: 1313 dm->state = DM_BALLOON_DOWN; 1314 balloon_down(dm, 1315 (struct dm_unballoon_request *)recv_buffer); 1316 break; 1317 1318 case DM_MEM_HOT_ADD_REQUEST: 1319 if (dm->state == DM_HOT_ADD) 1320 pr_warn("Currently hot-adding\n"); 1321 dm->state = DM_HOT_ADD; 1322 ha_msg = (struct dm_hot_add *)recv_buffer; 1323 if (ha_msg->hdr.size == sizeof(struct dm_hot_add)) { 1324 /* 1325 * This is a normal hot-add request specifying 1326 * hot-add memory. 1327 */ 1328 ha_pg_range = &ha_msg->range; 1329 dm->ha_wrk.ha_page_range = *ha_pg_range; 1330 dm->ha_wrk.ha_region_range.page_range = 0; 1331 } else { 1332 /* 1333 * Host is specifying that we first hot-add 1334 * a region and then partially populate this 1335 * region. 1336 */ 1337 dm->host_specified_ha_region = true; 1338 ha_pg_range = &ha_msg->range; 1339 ha_region = &ha_pg_range[1]; 1340 dm->ha_wrk.ha_page_range = *ha_pg_range; 1341 dm->ha_wrk.ha_region_range = *ha_region; 1342 } 1343 schedule_work(&dm_device.ha_wrk.wrk); 1344 break; 1345 1346 case DM_INFO_MESSAGE: 1347 process_info(dm, (struct dm_info_msg *)dm_msg); 1348 break; 1349 1350 default: 1351 pr_err("Unhandled message: type: %d\n", dm_hdr->type); 1352 1353 } 1354 } 1355 1356 } 1357 1358 static int balloon_probe(struct hv_device *dev, 1359 const struct hv_vmbus_device_id *dev_id) 1360 { 1361 int ret, t; 1362 struct dm_version_request version_req; 1363 struct dm_capabilities cap_msg; 1364 1365 do_hot_add = hot_add; 1366 1367 /* 1368 * First allocate a send buffer. 1369 */ 1370 1371 send_buffer = kmalloc(PAGE_SIZE, GFP_KERNEL); 1372 if (!send_buffer) 1373 return -ENOMEM; 1374 1375 ret = vmbus_open(dev->channel, dm_ring_size, dm_ring_size, NULL, 0, 1376 balloon_onchannelcallback, dev); 1377 1378 if (ret) 1379 goto probe_error0; 1380 1381 dm_device.dev = dev; 1382 dm_device.state = DM_INITIALIZING; 1383 dm_device.next_version = DYNMEM_PROTOCOL_VERSION_WIN7; 1384 init_completion(&dm_device.host_event); 1385 init_completion(&dm_device.config_event); 1386 INIT_LIST_HEAD(&dm_device.ha_region_list); 1387 INIT_WORK(&dm_device.balloon_wrk.wrk, balloon_up); 1388 INIT_WORK(&dm_device.ha_wrk.wrk, hot_add_req); 1389 dm_device.host_specified_ha_region = false; 1390 1391 dm_device.thread = 1392 kthread_run(dm_thread_func, &dm_device, "hv_balloon"); 1393 if (IS_ERR(dm_device.thread)) { 1394 ret = PTR_ERR(dm_device.thread); 1395 goto probe_error1; 1396 } 1397 1398 #ifdef CONFIG_MEMORY_HOTPLUG 1399 set_online_page_callback(&hv_online_page); 1400 #endif 1401 1402 hv_set_drvdata(dev, &dm_device); 1403 /* 1404 * Initiate the hand shake with the host and negotiate 1405 * a version that the host can support. We start with the 1406 * highest version number and go down if the host cannot 1407 * support it. 1408 */ 1409 memset(&version_req, 0, sizeof(struct dm_version_request)); 1410 version_req.hdr.type = DM_VERSION_REQUEST; 1411 version_req.hdr.size = sizeof(struct dm_version_request); 1412 version_req.hdr.trans_id = atomic_inc_return(&trans_id); 1413 version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN8; 1414 version_req.is_last_attempt = 0; 1415 1416 ret = vmbus_sendpacket(dev->channel, &version_req, 1417 sizeof(struct dm_version_request), 1418 (unsigned long)NULL, 1419 VM_PKT_DATA_INBAND, 0); 1420 if (ret) 1421 goto probe_error2; 1422 1423 t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ); 1424 if (t == 0) { 1425 ret = -ETIMEDOUT; 1426 goto probe_error2; 1427 } 1428 1429 /* 1430 * If we could not negotiate a compatible version with the host 1431 * fail the probe function. 1432 */ 1433 if (dm_device.state == DM_INIT_ERROR) { 1434 ret = -ETIMEDOUT; 1435 goto probe_error2; 1436 } 1437 /* 1438 * Now submit our capabilities to the host. 1439 */ 1440 memset(&cap_msg, 0, sizeof(struct dm_capabilities)); 1441 cap_msg.hdr.type = DM_CAPABILITIES_REPORT; 1442 cap_msg.hdr.size = sizeof(struct dm_capabilities); 1443 cap_msg.hdr.trans_id = atomic_inc_return(&trans_id); 1444 1445 cap_msg.caps.cap_bits.balloon = 1; 1446 cap_msg.caps.cap_bits.hot_add = 1; 1447 1448 /* 1449 * Specify our alignment requirements as it relates 1450 * memory hot-add. Specify 128MB alignment. 1451 */ 1452 cap_msg.caps.cap_bits.hot_add_alignment = 7; 1453 1454 /* 1455 * Currently the host does not use these 1456 * values and we set them to what is done in the 1457 * Windows driver. 1458 */ 1459 cap_msg.min_page_cnt = 0; 1460 cap_msg.max_page_number = -1; 1461 1462 ret = vmbus_sendpacket(dev->channel, &cap_msg, 1463 sizeof(struct dm_capabilities), 1464 (unsigned long)NULL, 1465 VM_PKT_DATA_INBAND, 0); 1466 if (ret) 1467 goto probe_error2; 1468 1469 t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ); 1470 if (t == 0) { 1471 ret = -ETIMEDOUT; 1472 goto probe_error2; 1473 } 1474 1475 /* 1476 * If the host does not like our capabilities, 1477 * fail the probe function. 1478 */ 1479 if (dm_device.state == DM_INIT_ERROR) { 1480 ret = -ETIMEDOUT; 1481 goto probe_error2; 1482 } 1483 1484 dm_device.state = DM_INITIALIZED; 1485 1486 return 0; 1487 1488 probe_error2: 1489 #ifdef CONFIG_MEMORY_HOTPLUG 1490 restore_online_page_callback(&hv_online_page); 1491 #endif 1492 kthread_stop(dm_device.thread); 1493 1494 probe_error1: 1495 vmbus_close(dev->channel); 1496 probe_error0: 1497 kfree(send_buffer); 1498 return ret; 1499 } 1500 1501 static int balloon_remove(struct hv_device *dev) 1502 { 1503 struct hv_dynmem_device *dm = hv_get_drvdata(dev); 1504 struct list_head *cur, *tmp; 1505 struct hv_hotadd_state *has; 1506 1507 if (dm->num_pages_ballooned != 0) 1508 pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned); 1509 1510 cancel_work_sync(&dm->balloon_wrk.wrk); 1511 cancel_work_sync(&dm->ha_wrk.wrk); 1512 1513 vmbus_close(dev->channel); 1514 kthread_stop(dm->thread); 1515 kfree(send_buffer); 1516 #ifdef CONFIG_MEMORY_HOTPLUG 1517 restore_online_page_callback(&hv_online_page); 1518 #endif 1519 list_for_each_safe(cur, tmp, &dm->ha_region_list) { 1520 has = list_entry(cur, struct hv_hotadd_state, list); 1521 list_del(&has->list); 1522 kfree(has); 1523 } 1524 1525 return 0; 1526 } 1527 1528 static const struct hv_vmbus_device_id id_table[] = { 1529 /* Dynamic Memory Class ID */ 1530 /* 525074DC-8985-46e2-8057-A307DC18A502 */ 1531 { HV_DM_GUID, }, 1532 { }, 1533 }; 1534 1535 MODULE_DEVICE_TABLE(vmbus, id_table); 1536 1537 static struct hv_driver balloon_drv = { 1538 .name = "hv_balloon", 1539 .id_table = id_table, 1540 .probe = balloon_probe, 1541 .remove = balloon_remove, 1542 }; 1543 1544 static int __init init_balloon_drv(void) 1545 { 1546 1547 return vmbus_driver_register(&balloon_drv); 1548 } 1549 1550 module_init(init_balloon_drv); 1551 1552 MODULE_DESCRIPTION("Hyper-V Balloon"); 1553 MODULE_LICENSE("GPL"); 1554