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_start_pfn: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_start_pfn; 441 unsigned long covered_end_pfn; 442 unsigned long ha_end_pfn; 443 unsigned long end_pfn; 444 /* 445 * A list of gaps. 446 */ 447 struct list_head gap_list; 448 }; 449 450 struct hv_hotadd_gap { 451 struct list_head list; 452 unsigned long start_pfn; 453 unsigned long end_pfn; 454 }; 455 456 struct balloon_state { 457 __u32 num_pages; 458 struct work_struct wrk; 459 }; 460 461 struct hot_add_wrk { 462 union dm_mem_page_range ha_page_range; 463 union dm_mem_page_range ha_region_range; 464 struct work_struct wrk; 465 }; 466 467 static bool hot_add = true; 468 static bool do_hot_add; 469 /* 470 * Delay reporting memory pressure by 471 * the specified number of seconds. 472 */ 473 static uint pressure_report_delay = 45; 474 475 /* 476 * The last time we posted a pressure report to host. 477 */ 478 static unsigned long last_post_time; 479 480 module_param(hot_add, bool, (S_IRUGO | S_IWUSR)); 481 MODULE_PARM_DESC(hot_add, "If set attempt memory hot_add"); 482 483 module_param(pressure_report_delay, uint, (S_IRUGO | S_IWUSR)); 484 MODULE_PARM_DESC(pressure_report_delay, "Delay in secs in reporting pressure"); 485 static atomic_t trans_id = ATOMIC_INIT(0); 486 487 static int dm_ring_size = (5 * PAGE_SIZE); 488 489 /* 490 * Driver specific state. 491 */ 492 493 enum hv_dm_state { 494 DM_INITIALIZING = 0, 495 DM_INITIALIZED, 496 DM_BALLOON_UP, 497 DM_BALLOON_DOWN, 498 DM_HOT_ADD, 499 DM_INIT_ERROR 500 }; 501 502 503 static __u8 recv_buffer[PAGE_SIZE]; 504 static __u8 *send_buffer; 505 #define PAGES_IN_2M 512 506 #define HA_CHUNK (32 * 1024) 507 508 struct hv_dynmem_device { 509 struct hv_device *dev; 510 enum hv_dm_state state; 511 struct completion host_event; 512 struct completion config_event; 513 514 /* 515 * Number of pages we have currently ballooned out. 516 */ 517 unsigned int num_pages_ballooned; 518 unsigned int num_pages_onlined; 519 unsigned int num_pages_added; 520 521 /* 522 * State to manage the ballooning (up) operation. 523 */ 524 struct balloon_state balloon_wrk; 525 526 /* 527 * State to execute the "hot-add" operation. 528 */ 529 struct hot_add_wrk ha_wrk; 530 531 /* 532 * This state tracks if the host has specified a hot-add 533 * region. 534 */ 535 bool host_specified_ha_region; 536 537 /* 538 * State to synchronize hot-add. 539 */ 540 struct completion ol_waitevent; 541 bool ha_waiting; 542 /* 543 * This thread handles hot-add 544 * requests from the host as well as notifying 545 * the host with regards to memory pressure in 546 * the guest. 547 */ 548 struct task_struct *thread; 549 550 /* 551 * Protects ha_region_list, num_pages_onlined counter and individual 552 * regions from ha_region_list. 553 */ 554 spinlock_t ha_lock; 555 556 /* 557 * A list of hot-add regions. 558 */ 559 struct list_head ha_region_list; 560 561 /* 562 * We start with the highest version we can support 563 * and downgrade based on the host; we save here the 564 * next version to try. 565 */ 566 __u32 next_version; 567 568 /* 569 * The negotiated version agreed by host. 570 */ 571 __u32 version; 572 }; 573 574 static struct hv_dynmem_device dm_device; 575 576 static void post_status(struct hv_dynmem_device *dm); 577 578 #ifdef CONFIG_MEMORY_HOTPLUG 579 static int hv_memory_notifier(struct notifier_block *nb, unsigned long val, 580 void *v) 581 { 582 struct memory_notify *mem = (struct memory_notify *)v; 583 unsigned long flags; 584 585 switch (val) { 586 case MEM_ONLINE: 587 case MEM_CANCEL_ONLINE: 588 if (dm_device.ha_waiting) { 589 dm_device.ha_waiting = false; 590 complete(&dm_device.ol_waitevent); 591 } 592 break; 593 594 case MEM_OFFLINE: 595 spin_lock_irqsave(&dm_device.ha_lock, flags); 596 dm_device.num_pages_onlined -= mem->nr_pages; 597 spin_unlock_irqrestore(&dm_device.ha_lock, flags); 598 break; 599 case MEM_GOING_ONLINE: 600 case MEM_GOING_OFFLINE: 601 case MEM_CANCEL_OFFLINE: 602 break; 603 } 604 return NOTIFY_OK; 605 } 606 607 static struct notifier_block hv_memory_nb = { 608 .notifier_call = hv_memory_notifier, 609 .priority = 0 610 }; 611 612 /* Check if the particular page is backed and can be onlined and online it. */ 613 static void hv_page_online_one(struct hv_hotadd_state *has, struct page *pg) 614 { 615 unsigned long cur_start_pgp; 616 unsigned long cur_end_pgp; 617 struct hv_hotadd_gap *gap; 618 619 cur_start_pgp = (unsigned long)pfn_to_page(has->covered_start_pfn); 620 cur_end_pgp = (unsigned long)pfn_to_page(has->covered_end_pfn); 621 622 /* The page is not backed. */ 623 if (((unsigned long)pg < cur_start_pgp) || 624 ((unsigned long)pg >= cur_end_pgp)) 625 return; 626 627 /* Check for gaps. */ 628 list_for_each_entry(gap, &has->gap_list, list) { 629 cur_start_pgp = (unsigned long) 630 pfn_to_page(gap->start_pfn); 631 cur_end_pgp = (unsigned long) 632 pfn_to_page(gap->end_pfn); 633 if (((unsigned long)pg >= cur_start_pgp) && 634 ((unsigned long)pg < cur_end_pgp)) { 635 return; 636 } 637 } 638 639 /* This frame is currently backed; online the page. */ 640 __online_page_set_limits(pg); 641 __online_page_increment_counters(pg); 642 __online_page_free(pg); 643 644 WARN_ON_ONCE(!spin_is_locked(&dm_device.ha_lock)); 645 dm_device.num_pages_onlined++; 646 } 647 648 static void hv_bring_pgs_online(struct hv_hotadd_state *has, 649 unsigned long start_pfn, unsigned long size) 650 { 651 int i; 652 653 pr_debug("Online %lu pages starting at pfn 0x%lx\n", size, start_pfn); 654 for (i = 0; i < size; i++) 655 hv_page_online_one(has, pfn_to_page(start_pfn + i)); 656 } 657 658 static void hv_mem_hot_add(unsigned long start, unsigned long size, 659 unsigned long pfn_count, 660 struct hv_hotadd_state *has) 661 { 662 int ret = 0; 663 int i, nid; 664 unsigned long start_pfn; 665 unsigned long processed_pfn; 666 unsigned long total_pfn = pfn_count; 667 unsigned long flags; 668 669 for (i = 0; i < (size/HA_CHUNK); i++) { 670 start_pfn = start + (i * HA_CHUNK); 671 672 spin_lock_irqsave(&dm_device.ha_lock, flags); 673 has->ha_end_pfn += HA_CHUNK; 674 675 if (total_pfn > HA_CHUNK) { 676 processed_pfn = HA_CHUNK; 677 total_pfn -= HA_CHUNK; 678 } else { 679 processed_pfn = total_pfn; 680 total_pfn = 0; 681 } 682 683 has->covered_end_pfn += processed_pfn; 684 spin_unlock_irqrestore(&dm_device.ha_lock, flags); 685 686 init_completion(&dm_device.ol_waitevent); 687 dm_device.ha_waiting = !memhp_auto_online; 688 689 nid = memory_add_physaddr_to_nid(PFN_PHYS(start_pfn)); 690 ret = add_memory(nid, PFN_PHYS((start_pfn)), 691 (HA_CHUNK << PAGE_SHIFT)); 692 693 if (ret) { 694 pr_warn("hot_add memory failed error is %d\n", ret); 695 if (ret == -EEXIST) { 696 /* 697 * This error indicates that the error 698 * is not a transient failure. This is the 699 * case where the guest's physical address map 700 * precludes hot adding memory. Stop all further 701 * memory hot-add. 702 */ 703 do_hot_add = false; 704 } 705 spin_lock_irqsave(&dm_device.ha_lock, flags); 706 has->ha_end_pfn -= HA_CHUNK; 707 has->covered_end_pfn -= processed_pfn; 708 spin_unlock_irqrestore(&dm_device.ha_lock, flags); 709 break; 710 } 711 712 /* 713 * Wait for the memory block to be onlined when memory onlining 714 * is done outside of kernel (memhp_auto_online). Since the hot 715 * add has succeeded, it is ok to proceed even if the pages in 716 * the hot added region have not been "onlined" within the 717 * allowed time. 718 */ 719 if (dm_device.ha_waiting) 720 wait_for_completion_timeout(&dm_device.ol_waitevent, 721 5*HZ); 722 post_status(&dm_device); 723 } 724 } 725 726 static void hv_online_page(struct page *pg) 727 { 728 struct hv_hotadd_state *has; 729 unsigned long cur_start_pgp; 730 unsigned long cur_end_pgp; 731 unsigned long flags; 732 733 spin_lock_irqsave(&dm_device.ha_lock, flags); 734 list_for_each_entry(has, &dm_device.ha_region_list, list) { 735 cur_start_pgp = (unsigned long) 736 pfn_to_page(has->start_pfn); 737 cur_end_pgp = (unsigned long)pfn_to_page(has->end_pfn); 738 739 /* The page belongs to a different HAS. */ 740 if (((unsigned long)pg < cur_start_pgp) || 741 ((unsigned long)pg >= cur_end_pgp)) 742 continue; 743 744 hv_page_online_one(has, pg); 745 break; 746 } 747 spin_unlock_irqrestore(&dm_device.ha_lock, flags); 748 } 749 750 static int pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt) 751 { 752 struct hv_hotadd_state *has; 753 struct hv_hotadd_gap *gap; 754 unsigned long residual, new_inc; 755 int ret = 0; 756 unsigned long flags; 757 758 spin_lock_irqsave(&dm_device.ha_lock, flags); 759 list_for_each_entry(has, &dm_device.ha_region_list, list) { 760 /* 761 * If the pfn range we are dealing with is not in the current 762 * "hot add block", move on. 763 */ 764 if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn) 765 continue; 766 767 /* 768 * If the current start pfn is not where the covered_end 769 * is, create a gap and update covered_end_pfn. 770 */ 771 if (has->covered_end_pfn != start_pfn) { 772 gap = kzalloc(sizeof(struct hv_hotadd_gap), GFP_ATOMIC); 773 if (!gap) { 774 ret = -ENOMEM; 775 break; 776 } 777 778 INIT_LIST_HEAD(&gap->list); 779 gap->start_pfn = has->covered_end_pfn; 780 gap->end_pfn = start_pfn; 781 list_add_tail(&gap->list, &has->gap_list); 782 783 has->covered_end_pfn = start_pfn; 784 } 785 786 /* 787 * If the current hot add-request extends beyond 788 * our current limit; extend it. 789 */ 790 if ((start_pfn + pfn_cnt) > has->end_pfn) { 791 residual = (start_pfn + pfn_cnt - has->end_pfn); 792 /* 793 * Extend the region by multiples of HA_CHUNK. 794 */ 795 new_inc = (residual / HA_CHUNK) * HA_CHUNK; 796 if (residual % HA_CHUNK) 797 new_inc += HA_CHUNK; 798 799 has->end_pfn += new_inc; 800 } 801 802 ret = 1; 803 break; 804 } 805 spin_unlock_irqrestore(&dm_device.ha_lock, flags); 806 807 return ret; 808 } 809 810 static unsigned long handle_pg_range(unsigned long pg_start, 811 unsigned long pg_count) 812 { 813 unsigned long start_pfn = pg_start; 814 unsigned long pfn_cnt = pg_count; 815 unsigned long size; 816 struct hv_hotadd_state *has; 817 unsigned long pgs_ol = 0; 818 unsigned long old_covered_state; 819 unsigned long res = 0, flags; 820 821 pr_debug("Hot adding %lu pages starting at pfn 0x%lx.\n", pg_count, 822 pg_start); 823 824 spin_lock_irqsave(&dm_device.ha_lock, flags); 825 list_for_each_entry(has, &dm_device.ha_region_list, list) { 826 /* 827 * If the pfn range we are dealing with is not in the current 828 * "hot add block", move on. 829 */ 830 if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn) 831 continue; 832 833 old_covered_state = has->covered_end_pfn; 834 835 if (start_pfn < has->ha_end_pfn) { 836 /* 837 * This is the case where we are backing pages 838 * in an already hot added region. Bring 839 * these pages online first. 840 */ 841 pgs_ol = has->ha_end_pfn - start_pfn; 842 if (pgs_ol > pfn_cnt) 843 pgs_ol = pfn_cnt; 844 845 has->covered_end_pfn += pgs_ol; 846 pfn_cnt -= pgs_ol; 847 /* 848 * Check if the corresponding memory block is already 849 * online by checking its last previously backed page. 850 * In case it is we need to bring rest (which was not 851 * backed previously) online too. 852 */ 853 if (start_pfn > has->start_pfn && 854 !PageReserved(pfn_to_page(start_pfn - 1))) 855 hv_bring_pgs_online(has, start_pfn, pgs_ol); 856 857 } 858 859 if ((has->ha_end_pfn < has->end_pfn) && (pfn_cnt > 0)) { 860 /* 861 * We have some residual hot add range 862 * that needs to be hot added; hot add 863 * it now. Hot add a multiple of 864 * of HA_CHUNK that fully covers the pages 865 * we have. 866 */ 867 size = (has->end_pfn - has->ha_end_pfn); 868 if (pfn_cnt <= size) { 869 size = ((pfn_cnt / HA_CHUNK) * HA_CHUNK); 870 if (pfn_cnt % HA_CHUNK) 871 size += HA_CHUNK; 872 } else { 873 pfn_cnt = size; 874 } 875 spin_unlock_irqrestore(&dm_device.ha_lock, flags); 876 hv_mem_hot_add(has->ha_end_pfn, size, pfn_cnt, has); 877 spin_lock_irqsave(&dm_device.ha_lock, flags); 878 } 879 /* 880 * If we managed to online any pages that were given to us, 881 * we declare success. 882 */ 883 res = has->covered_end_pfn - old_covered_state; 884 break; 885 } 886 spin_unlock_irqrestore(&dm_device.ha_lock, flags); 887 888 return res; 889 } 890 891 static unsigned long process_hot_add(unsigned long pg_start, 892 unsigned long pfn_cnt, 893 unsigned long rg_start, 894 unsigned long rg_size) 895 { 896 struct hv_hotadd_state *ha_region = NULL; 897 int covered; 898 unsigned long flags; 899 900 if (pfn_cnt == 0) 901 return 0; 902 903 if (!dm_device.host_specified_ha_region) { 904 covered = pfn_covered(pg_start, pfn_cnt); 905 if (covered < 0) 906 return 0; 907 908 if (covered) 909 goto do_pg_range; 910 } 911 912 /* 913 * If the host has specified a hot-add range; deal with it first. 914 */ 915 916 if (rg_size != 0) { 917 ha_region = kzalloc(sizeof(struct hv_hotadd_state), GFP_KERNEL); 918 if (!ha_region) 919 return 0; 920 921 INIT_LIST_HEAD(&ha_region->list); 922 INIT_LIST_HEAD(&ha_region->gap_list); 923 924 ha_region->start_pfn = rg_start; 925 ha_region->ha_end_pfn = rg_start; 926 ha_region->covered_start_pfn = pg_start; 927 ha_region->covered_end_pfn = pg_start; 928 ha_region->end_pfn = rg_start + rg_size; 929 930 spin_lock_irqsave(&dm_device.ha_lock, flags); 931 list_add_tail(&ha_region->list, &dm_device.ha_region_list); 932 spin_unlock_irqrestore(&dm_device.ha_lock, flags); 933 } 934 935 do_pg_range: 936 /* 937 * Process the page range specified; bringing them 938 * online if possible. 939 */ 940 return handle_pg_range(pg_start, pfn_cnt); 941 } 942 943 #endif 944 945 static void hot_add_req(struct work_struct *dummy) 946 { 947 struct dm_hot_add_response resp; 948 #ifdef CONFIG_MEMORY_HOTPLUG 949 unsigned long pg_start, pfn_cnt; 950 unsigned long rg_start, rg_sz; 951 #endif 952 struct hv_dynmem_device *dm = &dm_device; 953 954 memset(&resp, 0, sizeof(struct dm_hot_add_response)); 955 resp.hdr.type = DM_MEM_HOT_ADD_RESPONSE; 956 resp.hdr.size = sizeof(struct dm_hot_add_response); 957 958 #ifdef CONFIG_MEMORY_HOTPLUG 959 pg_start = dm->ha_wrk.ha_page_range.finfo.start_page; 960 pfn_cnt = dm->ha_wrk.ha_page_range.finfo.page_cnt; 961 962 rg_start = dm->ha_wrk.ha_region_range.finfo.start_page; 963 rg_sz = dm->ha_wrk.ha_region_range.finfo.page_cnt; 964 965 if ((rg_start == 0) && (!dm->host_specified_ha_region)) { 966 unsigned long region_size; 967 unsigned long region_start; 968 969 /* 970 * The host has not specified the hot-add region. 971 * Based on the hot-add page range being specified, 972 * compute a hot-add region that can cover the pages 973 * that need to be hot-added while ensuring the alignment 974 * and size requirements of Linux as it relates to hot-add. 975 */ 976 region_start = pg_start; 977 region_size = (pfn_cnt / HA_CHUNK) * HA_CHUNK; 978 if (pfn_cnt % HA_CHUNK) 979 region_size += HA_CHUNK; 980 981 region_start = (pg_start / HA_CHUNK) * HA_CHUNK; 982 983 rg_start = region_start; 984 rg_sz = region_size; 985 } 986 987 if (do_hot_add) 988 resp.page_count = process_hot_add(pg_start, pfn_cnt, 989 rg_start, rg_sz); 990 991 dm->num_pages_added += resp.page_count; 992 #endif 993 /* 994 * The result field of the response structure has the 995 * following semantics: 996 * 997 * 1. If all or some pages hot-added: Guest should return success. 998 * 999 * 2. If no pages could be hot-added: 1000 * 1001 * If the guest returns success, then the host 1002 * will not attempt any further hot-add operations. This 1003 * signifies a permanent failure. 1004 * 1005 * If the guest returns failure, then this failure will be 1006 * treated as a transient failure and the host may retry the 1007 * hot-add operation after some delay. 1008 */ 1009 if (resp.page_count > 0) 1010 resp.result = 1; 1011 else if (!do_hot_add) 1012 resp.result = 1; 1013 else 1014 resp.result = 0; 1015 1016 if (!do_hot_add || (resp.page_count == 0)) 1017 pr_info("Memory hot add failed\n"); 1018 1019 dm->state = DM_INITIALIZED; 1020 resp.hdr.trans_id = atomic_inc_return(&trans_id); 1021 vmbus_sendpacket(dm->dev->channel, &resp, 1022 sizeof(struct dm_hot_add_response), 1023 (unsigned long)NULL, 1024 VM_PKT_DATA_INBAND, 0); 1025 } 1026 1027 static void process_info(struct hv_dynmem_device *dm, struct dm_info_msg *msg) 1028 { 1029 struct dm_info_header *info_hdr; 1030 1031 info_hdr = (struct dm_info_header *)msg->info; 1032 1033 switch (info_hdr->type) { 1034 case INFO_TYPE_MAX_PAGE_CNT: 1035 if (info_hdr->data_size == sizeof(__u64)) { 1036 __u64 *max_page_count = (__u64 *)&info_hdr[1]; 1037 1038 pr_info("Max. dynamic memory size: %llu MB\n", 1039 (*max_page_count) >> (20 - PAGE_SHIFT)); 1040 } 1041 1042 break; 1043 default: 1044 pr_info("Received Unknown type: %d\n", info_hdr->type); 1045 } 1046 } 1047 1048 static unsigned long compute_balloon_floor(void) 1049 { 1050 unsigned long min_pages; 1051 #define MB2PAGES(mb) ((mb) << (20 - PAGE_SHIFT)) 1052 /* Simple continuous piecewiese linear function: 1053 * max MiB -> min MiB gradient 1054 * 0 0 1055 * 16 16 1056 * 32 24 1057 * 128 72 (1/2) 1058 * 512 168 (1/4) 1059 * 2048 360 (1/8) 1060 * 8192 744 (1/16) 1061 * 32768 1512 (1/32) 1062 */ 1063 if (totalram_pages < MB2PAGES(128)) 1064 min_pages = MB2PAGES(8) + (totalram_pages >> 1); 1065 else if (totalram_pages < MB2PAGES(512)) 1066 min_pages = MB2PAGES(40) + (totalram_pages >> 2); 1067 else if (totalram_pages < MB2PAGES(2048)) 1068 min_pages = MB2PAGES(104) + (totalram_pages >> 3); 1069 else if (totalram_pages < MB2PAGES(8192)) 1070 min_pages = MB2PAGES(232) + (totalram_pages >> 4); 1071 else 1072 min_pages = MB2PAGES(488) + (totalram_pages >> 5); 1073 #undef MB2PAGES 1074 return min_pages; 1075 } 1076 1077 /* 1078 * Post our status as it relates memory pressure to the 1079 * host. Host expects the guests to post this status 1080 * periodically at 1 second intervals. 1081 * 1082 * The metrics specified in this protocol are very Windows 1083 * specific and so we cook up numbers here to convey our memory 1084 * pressure. 1085 */ 1086 1087 static void post_status(struct hv_dynmem_device *dm) 1088 { 1089 struct dm_status status; 1090 unsigned long now = jiffies; 1091 unsigned long last_post = last_post_time; 1092 1093 if (pressure_report_delay > 0) { 1094 --pressure_report_delay; 1095 return; 1096 } 1097 1098 if (!time_after(now, (last_post_time + HZ))) 1099 return; 1100 1101 memset(&status, 0, sizeof(struct dm_status)); 1102 status.hdr.type = DM_STATUS_REPORT; 1103 status.hdr.size = sizeof(struct dm_status); 1104 status.hdr.trans_id = atomic_inc_return(&trans_id); 1105 1106 /* 1107 * The host expects the guest to report free and committed memory. 1108 * Furthermore, the host expects the pressure information to include 1109 * the ballooned out pages. For a given amount of memory that we are 1110 * managing we need to compute a floor below which we should not 1111 * balloon. Compute this and add it to the pressure report. 1112 * We also need to report all offline pages (num_pages_added - 1113 * num_pages_onlined) as committed to the host, otherwise it can try 1114 * asking us to balloon them out. 1115 */ 1116 status.num_avail = si_mem_available(); 1117 status.num_committed = vm_memory_committed() + 1118 dm->num_pages_ballooned + 1119 (dm->num_pages_added > dm->num_pages_onlined ? 1120 dm->num_pages_added - dm->num_pages_onlined : 0) + 1121 compute_balloon_floor(); 1122 1123 /* 1124 * If our transaction ID is no longer current, just don't 1125 * send the status. This can happen if we were interrupted 1126 * after we picked our transaction ID. 1127 */ 1128 if (status.hdr.trans_id != atomic_read(&trans_id)) 1129 return; 1130 1131 /* 1132 * If the last post time that we sampled has changed, 1133 * we have raced, don't post the status. 1134 */ 1135 if (last_post != last_post_time) 1136 return; 1137 1138 last_post_time = jiffies; 1139 vmbus_sendpacket(dm->dev->channel, &status, 1140 sizeof(struct dm_status), 1141 (unsigned long)NULL, 1142 VM_PKT_DATA_INBAND, 0); 1143 1144 } 1145 1146 static void free_balloon_pages(struct hv_dynmem_device *dm, 1147 union dm_mem_page_range *range_array) 1148 { 1149 int num_pages = range_array->finfo.page_cnt; 1150 __u64 start_frame = range_array->finfo.start_page; 1151 struct page *pg; 1152 int i; 1153 1154 for (i = 0; i < num_pages; i++) { 1155 pg = pfn_to_page(i + start_frame); 1156 __free_page(pg); 1157 dm->num_pages_ballooned--; 1158 } 1159 } 1160 1161 1162 1163 static unsigned int alloc_balloon_pages(struct hv_dynmem_device *dm, 1164 unsigned int num_pages, 1165 struct dm_balloon_response *bl_resp, 1166 int alloc_unit) 1167 { 1168 unsigned int i = 0; 1169 struct page *pg; 1170 1171 if (num_pages < alloc_unit) 1172 return 0; 1173 1174 for (i = 0; (i * alloc_unit) < num_pages; i++) { 1175 if (bl_resp->hdr.size + sizeof(union dm_mem_page_range) > 1176 PAGE_SIZE) 1177 return i * alloc_unit; 1178 1179 /* 1180 * We execute this code in a thread context. Furthermore, 1181 * we don't want the kernel to try too hard. 1182 */ 1183 pg = alloc_pages(GFP_HIGHUSER | __GFP_NORETRY | 1184 __GFP_NOMEMALLOC | __GFP_NOWARN, 1185 get_order(alloc_unit << PAGE_SHIFT)); 1186 1187 if (!pg) 1188 return i * alloc_unit; 1189 1190 dm->num_pages_ballooned += alloc_unit; 1191 1192 /* 1193 * If we allocatted 2M pages; split them so we 1194 * can free them in any order we get. 1195 */ 1196 1197 if (alloc_unit != 1) 1198 split_page(pg, get_order(alloc_unit << PAGE_SHIFT)); 1199 1200 bl_resp->range_count++; 1201 bl_resp->range_array[i].finfo.start_page = 1202 page_to_pfn(pg); 1203 bl_resp->range_array[i].finfo.page_cnt = alloc_unit; 1204 bl_resp->hdr.size += sizeof(union dm_mem_page_range); 1205 1206 } 1207 1208 return num_pages; 1209 } 1210 1211 static void balloon_up(struct work_struct *dummy) 1212 { 1213 unsigned int num_pages = dm_device.balloon_wrk.num_pages; 1214 unsigned int num_ballooned = 0; 1215 struct dm_balloon_response *bl_resp; 1216 int alloc_unit; 1217 int ret; 1218 bool done = false; 1219 int i; 1220 long avail_pages; 1221 unsigned long floor; 1222 1223 /* The host balloons pages in 2M granularity. */ 1224 WARN_ON_ONCE(num_pages % PAGES_IN_2M != 0); 1225 1226 /* 1227 * We will attempt 2M allocations. However, if we fail to 1228 * allocate 2M chunks, we will go back to 4k allocations. 1229 */ 1230 alloc_unit = 512; 1231 1232 avail_pages = si_mem_available(); 1233 floor = compute_balloon_floor(); 1234 1235 /* Refuse to balloon below the floor, keep the 2M granularity. */ 1236 if (avail_pages < num_pages || avail_pages - num_pages < floor) { 1237 pr_warn("Balloon request will be partially fulfilled. %s\n", 1238 avail_pages < num_pages ? "Not enough memory." : 1239 "Balloon floor reached."); 1240 1241 num_pages = avail_pages > floor ? (avail_pages - floor) : 0; 1242 num_pages -= num_pages % PAGES_IN_2M; 1243 } 1244 1245 while (!done) { 1246 bl_resp = (struct dm_balloon_response *)send_buffer; 1247 memset(send_buffer, 0, PAGE_SIZE); 1248 bl_resp->hdr.type = DM_BALLOON_RESPONSE; 1249 bl_resp->hdr.size = sizeof(struct dm_balloon_response); 1250 bl_resp->more_pages = 1; 1251 1252 num_pages -= num_ballooned; 1253 num_ballooned = alloc_balloon_pages(&dm_device, num_pages, 1254 bl_resp, alloc_unit); 1255 1256 if (alloc_unit != 1 && num_ballooned == 0) { 1257 alloc_unit = 1; 1258 continue; 1259 } 1260 1261 if (num_ballooned == 0 || num_ballooned == num_pages) { 1262 pr_debug("Ballooned %u out of %u requested pages.\n", 1263 num_pages, dm_device.balloon_wrk.num_pages); 1264 1265 bl_resp->more_pages = 0; 1266 done = true; 1267 dm_device.state = DM_INITIALIZED; 1268 } 1269 1270 /* 1271 * We are pushing a lot of data through the channel; 1272 * deal with transient failures caused because of the 1273 * lack of space in the ring buffer. 1274 */ 1275 1276 do { 1277 bl_resp->hdr.trans_id = atomic_inc_return(&trans_id); 1278 ret = vmbus_sendpacket(dm_device.dev->channel, 1279 bl_resp, 1280 bl_resp->hdr.size, 1281 (unsigned long)NULL, 1282 VM_PKT_DATA_INBAND, 0); 1283 1284 if (ret == -EAGAIN) 1285 msleep(20); 1286 post_status(&dm_device); 1287 } while (ret == -EAGAIN); 1288 1289 if (ret) { 1290 /* 1291 * Free up the memory we allocatted. 1292 */ 1293 pr_info("Balloon response failed\n"); 1294 1295 for (i = 0; i < bl_resp->range_count; i++) 1296 free_balloon_pages(&dm_device, 1297 &bl_resp->range_array[i]); 1298 1299 done = true; 1300 } 1301 } 1302 1303 } 1304 1305 static void balloon_down(struct hv_dynmem_device *dm, 1306 struct dm_unballoon_request *req) 1307 { 1308 union dm_mem_page_range *range_array = req->range_array; 1309 int range_count = req->range_count; 1310 struct dm_unballoon_response resp; 1311 int i; 1312 unsigned int prev_pages_ballooned = dm->num_pages_ballooned; 1313 1314 for (i = 0; i < range_count; i++) { 1315 free_balloon_pages(dm, &range_array[i]); 1316 complete(&dm_device.config_event); 1317 } 1318 1319 pr_debug("Freed %u ballooned pages.\n", 1320 prev_pages_ballooned - dm->num_pages_ballooned); 1321 1322 if (req->more_pages == 1) 1323 return; 1324 1325 memset(&resp, 0, sizeof(struct dm_unballoon_response)); 1326 resp.hdr.type = DM_UNBALLOON_RESPONSE; 1327 resp.hdr.trans_id = atomic_inc_return(&trans_id); 1328 resp.hdr.size = sizeof(struct dm_unballoon_response); 1329 1330 vmbus_sendpacket(dm_device.dev->channel, &resp, 1331 sizeof(struct dm_unballoon_response), 1332 (unsigned long)NULL, 1333 VM_PKT_DATA_INBAND, 0); 1334 1335 dm->state = DM_INITIALIZED; 1336 } 1337 1338 static void balloon_onchannelcallback(void *context); 1339 1340 static int dm_thread_func(void *dm_dev) 1341 { 1342 struct hv_dynmem_device *dm = dm_dev; 1343 1344 while (!kthread_should_stop()) { 1345 wait_for_completion_interruptible_timeout( 1346 &dm_device.config_event, 1*HZ); 1347 /* 1348 * The host expects us to post information on the memory 1349 * pressure every second. 1350 */ 1351 reinit_completion(&dm_device.config_event); 1352 post_status(dm); 1353 } 1354 1355 return 0; 1356 } 1357 1358 1359 static void version_resp(struct hv_dynmem_device *dm, 1360 struct dm_version_response *vresp) 1361 { 1362 struct dm_version_request version_req; 1363 int ret; 1364 1365 if (vresp->is_accepted) { 1366 /* 1367 * We are done; wakeup the 1368 * context waiting for version 1369 * negotiation. 1370 */ 1371 complete(&dm->host_event); 1372 return; 1373 } 1374 /* 1375 * If there are more versions to try, continue 1376 * with negotiations; if not 1377 * shutdown the service since we are not able 1378 * to negotiate a suitable version number 1379 * with the host. 1380 */ 1381 if (dm->next_version == 0) 1382 goto version_error; 1383 1384 memset(&version_req, 0, sizeof(struct dm_version_request)); 1385 version_req.hdr.type = DM_VERSION_REQUEST; 1386 version_req.hdr.size = sizeof(struct dm_version_request); 1387 version_req.hdr.trans_id = atomic_inc_return(&trans_id); 1388 version_req.version.version = dm->next_version; 1389 dm->version = version_req.version.version; 1390 1391 /* 1392 * Set the next version to try in case current version fails. 1393 * Win7 protocol ought to be the last one to try. 1394 */ 1395 switch (version_req.version.version) { 1396 case DYNMEM_PROTOCOL_VERSION_WIN8: 1397 dm->next_version = DYNMEM_PROTOCOL_VERSION_WIN7; 1398 version_req.is_last_attempt = 0; 1399 break; 1400 default: 1401 dm->next_version = 0; 1402 version_req.is_last_attempt = 1; 1403 } 1404 1405 ret = vmbus_sendpacket(dm->dev->channel, &version_req, 1406 sizeof(struct dm_version_request), 1407 (unsigned long)NULL, 1408 VM_PKT_DATA_INBAND, 0); 1409 1410 if (ret) 1411 goto version_error; 1412 1413 return; 1414 1415 version_error: 1416 dm->state = DM_INIT_ERROR; 1417 complete(&dm->host_event); 1418 } 1419 1420 static void cap_resp(struct hv_dynmem_device *dm, 1421 struct dm_capabilities_resp_msg *cap_resp) 1422 { 1423 if (!cap_resp->is_accepted) { 1424 pr_info("Capabilities not accepted by host\n"); 1425 dm->state = DM_INIT_ERROR; 1426 } 1427 complete(&dm->host_event); 1428 } 1429 1430 static void balloon_onchannelcallback(void *context) 1431 { 1432 struct hv_device *dev = context; 1433 u32 recvlen; 1434 u64 requestid; 1435 struct dm_message *dm_msg; 1436 struct dm_header *dm_hdr; 1437 struct hv_dynmem_device *dm = hv_get_drvdata(dev); 1438 struct dm_balloon *bal_msg; 1439 struct dm_hot_add *ha_msg; 1440 union dm_mem_page_range *ha_pg_range; 1441 union dm_mem_page_range *ha_region; 1442 1443 memset(recv_buffer, 0, sizeof(recv_buffer)); 1444 vmbus_recvpacket(dev->channel, recv_buffer, 1445 PAGE_SIZE, &recvlen, &requestid); 1446 1447 if (recvlen > 0) { 1448 dm_msg = (struct dm_message *)recv_buffer; 1449 dm_hdr = &dm_msg->hdr; 1450 1451 switch (dm_hdr->type) { 1452 case DM_VERSION_RESPONSE: 1453 version_resp(dm, 1454 (struct dm_version_response *)dm_msg); 1455 break; 1456 1457 case DM_CAPABILITIES_RESPONSE: 1458 cap_resp(dm, 1459 (struct dm_capabilities_resp_msg *)dm_msg); 1460 break; 1461 1462 case DM_BALLOON_REQUEST: 1463 if (dm->state == DM_BALLOON_UP) 1464 pr_warn("Currently ballooning\n"); 1465 bal_msg = (struct dm_balloon *)recv_buffer; 1466 dm->state = DM_BALLOON_UP; 1467 dm_device.balloon_wrk.num_pages = bal_msg->num_pages; 1468 schedule_work(&dm_device.balloon_wrk.wrk); 1469 break; 1470 1471 case DM_UNBALLOON_REQUEST: 1472 dm->state = DM_BALLOON_DOWN; 1473 balloon_down(dm, 1474 (struct dm_unballoon_request *)recv_buffer); 1475 break; 1476 1477 case DM_MEM_HOT_ADD_REQUEST: 1478 if (dm->state == DM_HOT_ADD) 1479 pr_warn("Currently hot-adding\n"); 1480 dm->state = DM_HOT_ADD; 1481 ha_msg = (struct dm_hot_add *)recv_buffer; 1482 if (ha_msg->hdr.size == sizeof(struct dm_hot_add)) { 1483 /* 1484 * This is a normal hot-add request specifying 1485 * hot-add memory. 1486 */ 1487 dm->host_specified_ha_region = false; 1488 ha_pg_range = &ha_msg->range; 1489 dm->ha_wrk.ha_page_range = *ha_pg_range; 1490 dm->ha_wrk.ha_region_range.page_range = 0; 1491 } else { 1492 /* 1493 * Host is specifying that we first hot-add 1494 * a region and then partially populate this 1495 * region. 1496 */ 1497 dm->host_specified_ha_region = true; 1498 ha_pg_range = &ha_msg->range; 1499 ha_region = &ha_pg_range[1]; 1500 dm->ha_wrk.ha_page_range = *ha_pg_range; 1501 dm->ha_wrk.ha_region_range = *ha_region; 1502 } 1503 schedule_work(&dm_device.ha_wrk.wrk); 1504 break; 1505 1506 case DM_INFO_MESSAGE: 1507 process_info(dm, (struct dm_info_msg *)dm_msg); 1508 break; 1509 1510 default: 1511 pr_err("Unhandled message: type: %d\n", dm_hdr->type); 1512 1513 } 1514 } 1515 1516 } 1517 1518 static int balloon_probe(struct hv_device *dev, 1519 const struct hv_vmbus_device_id *dev_id) 1520 { 1521 int ret; 1522 unsigned long t; 1523 struct dm_version_request version_req; 1524 struct dm_capabilities cap_msg; 1525 1526 #ifdef CONFIG_MEMORY_HOTPLUG 1527 do_hot_add = hot_add; 1528 #else 1529 do_hot_add = false; 1530 #endif 1531 1532 /* 1533 * First allocate a send buffer. 1534 */ 1535 1536 send_buffer = kmalloc(PAGE_SIZE, GFP_KERNEL); 1537 if (!send_buffer) 1538 return -ENOMEM; 1539 1540 ret = vmbus_open(dev->channel, dm_ring_size, dm_ring_size, NULL, 0, 1541 balloon_onchannelcallback, dev); 1542 1543 if (ret) 1544 goto probe_error0; 1545 1546 dm_device.dev = dev; 1547 dm_device.state = DM_INITIALIZING; 1548 dm_device.next_version = DYNMEM_PROTOCOL_VERSION_WIN8; 1549 init_completion(&dm_device.host_event); 1550 init_completion(&dm_device.config_event); 1551 INIT_LIST_HEAD(&dm_device.ha_region_list); 1552 spin_lock_init(&dm_device.ha_lock); 1553 INIT_WORK(&dm_device.balloon_wrk.wrk, balloon_up); 1554 INIT_WORK(&dm_device.ha_wrk.wrk, hot_add_req); 1555 dm_device.host_specified_ha_region = false; 1556 1557 dm_device.thread = 1558 kthread_run(dm_thread_func, &dm_device, "hv_balloon"); 1559 if (IS_ERR(dm_device.thread)) { 1560 ret = PTR_ERR(dm_device.thread); 1561 goto probe_error1; 1562 } 1563 1564 #ifdef CONFIG_MEMORY_HOTPLUG 1565 set_online_page_callback(&hv_online_page); 1566 register_memory_notifier(&hv_memory_nb); 1567 #endif 1568 1569 hv_set_drvdata(dev, &dm_device); 1570 /* 1571 * Initiate the hand shake with the host and negotiate 1572 * a version that the host can support. We start with the 1573 * highest version number and go down if the host cannot 1574 * support it. 1575 */ 1576 memset(&version_req, 0, sizeof(struct dm_version_request)); 1577 version_req.hdr.type = DM_VERSION_REQUEST; 1578 version_req.hdr.size = sizeof(struct dm_version_request); 1579 version_req.hdr.trans_id = atomic_inc_return(&trans_id); 1580 version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN10; 1581 version_req.is_last_attempt = 0; 1582 dm_device.version = version_req.version.version; 1583 1584 ret = vmbus_sendpacket(dev->channel, &version_req, 1585 sizeof(struct dm_version_request), 1586 (unsigned long)NULL, 1587 VM_PKT_DATA_INBAND, 0); 1588 if (ret) 1589 goto probe_error2; 1590 1591 t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ); 1592 if (t == 0) { 1593 ret = -ETIMEDOUT; 1594 goto probe_error2; 1595 } 1596 1597 /* 1598 * If we could not negotiate a compatible version with the host 1599 * fail the probe function. 1600 */ 1601 if (dm_device.state == DM_INIT_ERROR) { 1602 ret = -ETIMEDOUT; 1603 goto probe_error2; 1604 } 1605 1606 pr_info("Using Dynamic Memory protocol version %u.%u\n", 1607 DYNMEM_MAJOR_VERSION(dm_device.version), 1608 DYNMEM_MINOR_VERSION(dm_device.version)); 1609 1610 /* 1611 * Now submit our capabilities to the host. 1612 */ 1613 memset(&cap_msg, 0, sizeof(struct dm_capabilities)); 1614 cap_msg.hdr.type = DM_CAPABILITIES_REPORT; 1615 cap_msg.hdr.size = sizeof(struct dm_capabilities); 1616 cap_msg.hdr.trans_id = atomic_inc_return(&trans_id); 1617 1618 cap_msg.caps.cap_bits.balloon = 1; 1619 cap_msg.caps.cap_bits.hot_add = 1; 1620 1621 /* 1622 * Specify our alignment requirements as it relates 1623 * memory hot-add. Specify 128MB alignment. 1624 */ 1625 cap_msg.caps.cap_bits.hot_add_alignment = 7; 1626 1627 /* 1628 * Currently the host does not use these 1629 * values and we set them to what is done in the 1630 * Windows driver. 1631 */ 1632 cap_msg.min_page_cnt = 0; 1633 cap_msg.max_page_number = -1; 1634 1635 ret = vmbus_sendpacket(dev->channel, &cap_msg, 1636 sizeof(struct dm_capabilities), 1637 (unsigned long)NULL, 1638 VM_PKT_DATA_INBAND, 0); 1639 if (ret) 1640 goto probe_error2; 1641 1642 t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ); 1643 if (t == 0) { 1644 ret = -ETIMEDOUT; 1645 goto probe_error2; 1646 } 1647 1648 /* 1649 * If the host does not like our capabilities, 1650 * fail the probe function. 1651 */ 1652 if (dm_device.state == DM_INIT_ERROR) { 1653 ret = -ETIMEDOUT; 1654 goto probe_error2; 1655 } 1656 1657 dm_device.state = DM_INITIALIZED; 1658 last_post_time = jiffies; 1659 1660 return 0; 1661 1662 probe_error2: 1663 #ifdef CONFIG_MEMORY_HOTPLUG 1664 restore_online_page_callback(&hv_online_page); 1665 #endif 1666 kthread_stop(dm_device.thread); 1667 1668 probe_error1: 1669 vmbus_close(dev->channel); 1670 probe_error0: 1671 kfree(send_buffer); 1672 return ret; 1673 } 1674 1675 static int balloon_remove(struct hv_device *dev) 1676 { 1677 struct hv_dynmem_device *dm = hv_get_drvdata(dev); 1678 struct hv_hotadd_state *has, *tmp; 1679 struct hv_hotadd_gap *gap, *tmp_gap; 1680 unsigned long flags; 1681 1682 if (dm->num_pages_ballooned != 0) 1683 pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned); 1684 1685 cancel_work_sync(&dm->balloon_wrk.wrk); 1686 cancel_work_sync(&dm->ha_wrk.wrk); 1687 1688 vmbus_close(dev->channel); 1689 kthread_stop(dm->thread); 1690 kfree(send_buffer); 1691 #ifdef CONFIG_MEMORY_HOTPLUG 1692 restore_online_page_callback(&hv_online_page); 1693 unregister_memory_notifier(&hv_memory_nb); 1694 #endif 1695 spin_lock_irqsave(&dm_device.ha_lock, flags); 1696 list_for_each_entry_safe(has, tmp, &dm->ha_region_list, list) { 1697 list_for_each_entry_safe(gap, tmp_gap, &has->gap_list, list) { 1698 list_del(&gap->list); 1699 kfree(gap); 1700 } 1701 list_del(&has->list); 1702 kfree(has); 1703 } 1704 spin_unlock_irqrestore(&dm_device.ha_lock, flags); 1705 1706 return 0; 1707 } 1708 1709 static const struct hv_vmbus_device_id id_table[] = { 1710 /* Dynamic Memory Class ID */ 1711 /* 525074DC-8985-46e2-8057-A307DC18A502 */ 1712 { HV_DM_GUID, }, 1713 { }, 1714 }; 1715 1716 MODULE_DEVICE_TABLE(vmbus, id_table); 1717 1718 static struct hv_driver balloon_drv = { 1719 .name = "hv_balloon", 1720 .id_table = id_table, 1721 .probe = balloon_probe, 1722 .remove = balloon_remove, 1723 }; 1724 1725 static int __init init_balloon_drv(void) 1726 { 1727 1728 return vmbus_driver_register(&balloon_drv); 1729 } 1730 1731 module_init(init_balloon_drv); 1732 1733 MODULE_DESCRIPTION("Hyper-V Balloon"); 1734 MODULE_LICENSE("GPL"); 1735