1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * Copyright (c) 2012, Microsoft Corporation. 4 * 5 * Author: 6 * K. Y. Srinivasan <kys@microsoft.com> 7 */ 8 9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 10 11#include <linux/cleanup.h> 12#include <linux/kernel.h> 13#include <linux/jiffies.h> 14#include <linux/mman.h> 15#include <linux/debugfs.h> 16#include <linux/delay.h> 17#include <linux/init.h> 18#include <linux/module.h> 19#include <linux/slab.h> 20#include <linux/kthread.h> 21#include <linux/completion.h> 22#include <linux/count_zeros.h> 23#include <linux/memory_hotplug.h> 24#include <linux/memory.h> 25#include <linux/notifier.h> 26#include <linux/percpu_counter.h> 27#include <linux/page_reporting.h> 28 29#include <linux/hyperv.h> 30#include <asm/hyperv-tlfs.h> 31 32#include <asm/mshyperv.h> 33 34#define CREATE_TRACE_POINTS 35#include "hv_trace_balloon.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 62enum { 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 80enum 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 110union dm_version { 111 struct { 112 __u16 minor_version; 113 __u16 major_version; 114 }; 115 __u32 version; 116} __packed; 117 118 119union 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 135union 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 161struct 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 172struct 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 192struct 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 210struct 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 221struct 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 238struct 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 number 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 264struct 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 283struct 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 304struct 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 327struct 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 341struct 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 */ 352 353struct 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 378struct 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 388enum 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 398struct 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 412struct 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 435struct 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 * A list of gaps. 444 */ 445 struct list_head gap_list; 446}; 447 448struct hv_hotadd_gap { 449 struct list_head list; 450 unsigned long start_pfn; 451 unsigned long end_pfn; 452}; 453 454struct balloon_state { 455 __u32 num_pages; 456 struct work_struct wrk; 457}; 458 459struct hot_add_wrk { 460 union dm_mem_page_range ha_page_range; 461 union dm_mem_page_range ha_region_range; 462 struct work_struct wrk; 463}; 464 465static bool allow_hibernation; 466static bool hot_add = true; 467static bool do_hot_add; 468/* 469 * Delay reporting memory pressure by 470 * the specified number of seconds. 471 */ 472static uint pressure_report_delay = 45; 473extern unsigned int page_reporting_order; 474#define HV_MAX_FAILURES 2 475 476/* 477 * The last time we posted a pressure report to host. 478 */ 479static unsigned long last_post_time; 480 481static int hv_hypercall_multi_failure; 482 483module_param(hot_add, bool, (S_IRUGO | S_IWUSR)); 484MODULE_PARM_DESC(hot_add, "If set attempt memory hot_add"); 485 486module_param(pressure_report_delay, uint, (S_IRUGO | S_IWUSR)); 487MODULE_PARM_DESC(pressure_report_delay, "Delay in secs in reporting pressure"); 488static atomic_t trans_id = ATOMIC_INIT(0); 489 490static int dm_ring_size = VMBUS_RING_SIZE(16 * 1024); 491 492/* 493 * Driver specific state. 494 */ 495 496enum hv_dm_state { 497 DM_INITIALIZING = 0, 498 DM_INITIALIZED, 499 DM_BALLOON_UP, 500 DM_BALLOON_DOWN, 501 DM_HOT_ADD, 502 DM_INIT_ERROR 503}; 504 505 506static __u8 recv_buffer[HV_HYP_PAGE_SIZE]; 507static __u8 balloon_up_send_buffer[HV_HYP_PAGE_SIZE]; 508#define PAGES_IN_2M (2 * 1024 * 1024 / PAGE_SIZE) 509#define HA_CHUNK (128 * 1024 * 1024 / PAGE_SIZE) 510 511struct hv_dynmem_device { 512 struct hv_device *dev; 513 enum hv_dm_state state; 514 struct completion host_event; 515 struct completion config_event; 516 517 /* 518 * Number of pages we have currently ballooned out. 519 */ 520 unsigned int num_pages_ballooned; 521 unsigned int num_pages_onlined; 522 unsigned int num_pages_added; 523 524 /* 525 * State to manage the ballooning (up) operation. 526 */ 527 struct balloon_state balloon_wrk; 528 529 /* 530 * State to execute the "hot-add" operation. 531 */ 532 struct hot_add_wrk ha_wrk; 533 534 /* 535 * This state tracks if the host has specified a hot-add 536 * region. 537 */ 538 bool host_specified_ha_region; 539 540 /* 541 * State to synchronize hot-add. 542 */ 543 struct completion ol_waitevent; 544 /* 545 * This thread handles hot-add 546 * requests from the host as well as notifying 547 * the host with regards to memory pressure in 548 * the guest. 549 */ 550 struct task_struct *thread; 551 552 /* 553 * Protects ha_region_list, num_pages_onlined counter and individual 554 * regions from ha_region_list. 555 */ 556 spinlock_t ha_lock; 557 558 /* 559 * A list of hot-add regions. 560 */ 561 struct list_head ha_region_list; 562 563 /* 564 * We start with the highest version we can support 565 * and downgrade based on the host; we save here the 566 * next version to try. 567 */ 568 __u32 next_version; 569 570 /* 571 * The negotiated version agreed by host. 572 */ 573 __u32 version; 574 575 struct page_reporting_dev_info pr_dev_info; 576 577 /* 578 * Maximum number of pages that can be hot_add-ed 579 */ 580 __u64 max_dynamic_page_count; 581}; 582 583static struct hv_dynmem_device dm_device; 584 585static void post_status(struct hv_dynmem_device *dm); 586 587static void enable_page_reporting(void); 588 589static void disable_page_reporting(void); 590 591#ifdef CONFIG_MEMORY_HOTPLUG 592static inline bool has_pfn_is_backed(struct hv_hotadd_state *has, 593 unsigned long pfn) 594{ 595 struct hv_hotadd_gap *gap; 596 597 /* The page is not backed. */ 598 if ((pfn < has->covered_start_pfn) || (pfn >= has->covered_end_pfn)) 599 return false; 600 601 /* Check for gaps. */ 602 list_for_each_entry(gap, &has->gap_list, list) { 603 if ((pfn >= gap->start_pfn) && (pfn < gap->end_pfn)) 604 return false; 605 } 606 607 return true; 608} 609 610static unsigned long hv_page_offline_check(unsigned long start_pfn, 611 unsigned long nr_pages) 612{ 613 unsigned long pfn = start_pfn, count = 0; 614 struct hv_hotadd_state *has; 615 bool found; 616 617 while (pfn < start_pfn + nr_pages) { 618 /* 619 * Search for HAS which covers the pfn and when we find one 620 * count how many consequitive PFNs are covered. 621 */ 622 found = false; 623 list_for_each_entry(has, &dm_device.ha_region_list, list) { 624 while ((pfn >= has->start_pfn) && 625 (pfn < has->end_pfn) && 626 (pfn < start_pfn + nr_pages)) { 627 found = true; 628 if (has_pfn_is_backed(has, pfn)) 629 count++; 630 pfn++; 631 } 632 } 633 634 /* 635 * This PFN is not in any HAS (e.g. we're offlining a region 636 * which was present at boot), no need to account for it. Go 637 * to the next one. 638 */ 639 if (!found) 640 pfn++; 641 } 642 643 return count; 644} 645 646static int hv_memory_notifier(struct notifier_block *nb, unsigned long val, 647 void *v) 648{ 649 struct memory_notify *mem = (struct memory_notify *)v; 650 unsigned long pfn_count; 651 652 switch (val) { 653 case MEM_ONLINE: 654 case MEM_CANCEL_ONLINE: 655 complete(&dm_device.ol_waitevent); 656 break; 657 658 case MEM_OFFLINE: 659 scoped_guard(spinlock_irqsave, &dm_device.ha_lock) { 660 pfn_count = hv_page_offline_check(mem->start_pfn, 661 mem->nr_pages); 662 if (pfn_count <= dm_device.num_pages_onlined) { 663 dm_device.num_pages_onlined -= pfn_count; 664 } else { 665 /* 666 * We're offlining more pages than we 667 * managed to online. This is 668 * unexpected. In any case don't let 669 * num_pages_onlined wrap around zero. 670 */ 671 WARN_ON_ONCE(1); 672 dm_device.num_pages_onlined = 0; 673 } 674 } 675 break; 676 case MEM_GOING_ONLINE: 677 case MEM_GOING_OFFLINE: 678 case MEM_CANCEL_OFFLINE: 679 break; 680 } 681 return NOTIFY_OK; 682} 683 684static struct notifier_block hv_memory_nb = { 685 .notifier_call = hv_memory_notifier, 686 .priority = 0 687}; 688 689/* Check if the particular page is backed and can be onlined and online it. */ 690static void hv_page_online_one(struct hv_hotadd_state *has, struct page *pg) 691{ 692 if (!has_pfn_is_backed(has, page_to_pfn(pg))) { 693 if (!PageOffline(pg)) 694 __SetPageOffline(pg); 695 return; 696 } 697 if (PageOffline(pg)) 698 __ClearPageOffline(pg); 699 700 /* This frame is currently backed; online the page. */ 701 generic_online_page(pg, 0); 702 703 lockdep_assert_held(&dm_device.ha_lock); 704 dm_device.num_pages_onlined++; 705} 706 707static void hv_bring_pgs_online(struct hv_hotadd_state *has, 708 unsigned long start_pfn, unsigned long size) 709{ 710 int i; 711 712 pr_debug("Online %lu pages starting at pfn 0x%lx\n", size, start_pfn); 713 for (i = 0; i < size; i++) 714 hv_page_online_one(has, pfn_to_page(start_pfn + i)); 715} 716 717static void hv_mem_hot_add(unsigned long start, unsigned long size, 718 unsigned long pfn_count, 719 struct hv_hotadd_state *has) 720{ 721 int ret = 0; 722 int i, nid; 723 unsigned long start_pfn; 724 unsigned long processed_pfn; 725 unsigned long total_pfn = pfn_count; 726 727 for (i = 0; i < (size/HA_CHUNK); i++) { 728 start_pfn = start + (i * HA_CHUNK); 729 730 scoped_guard(spinlock_irqsave, &dm_device.ha_lock) { 731 has->ha_end_pfn += HA_CHUNK; 732 733 if (total_pfn > HA_CHUNK) { 734 processed_pfn = HA_CHUNK; 735 total_pfn -= HA_CHUNK; 736 } else { 737 processed_pfn = total_pfn; 738 total_pfn = 0; 739 } 740 741 has->covered_end_pfn += processed_pfn; 742 } 743 744 reinit_completion(&dm_device.ol_waitevent); 745 746 nid = memory_add_physaddr_to_nid(PFN_PHYS(start_pfn)); 747 ret = add_memory(nid, PFN_PHYS((start_pfn)), 748 (HA_CHUNK << PAGE_SHIFT), MHP_MERGE_RESOURCE); 749 750 if (ret) { 751 pr_err("hot_add memory failed error is %d\n", ret); 752 if (ret == -EEXIST) { 753 /* 754 * This error indicates that the error 755 * is not a transient failure. This is the 756 * case where the guest's physical address map 757 * precludes hot adding memory. Stop all further 758 * memory hot-add. 759 */ 760 do_hot_add = false; 761 } 762 scoped_guard(spinlock_irqsave, &dm_device.ha_lock) { 763 has->ha_end_pfn -= HA_CHUNK; 764 has->covered_end_pfn -= processed_pfn; 765 } 766 break; 767 } 768 769 /* 770 * Wait for memory to get onlined. If the kernel onlined the 771 * memory when adding it, this will return directly. Otherwise, 772 * it will wait for user space to online the memory. This helps 773 * to avoid adding memory faster than it is getting onlined. As 774 * adding succeeded, it is ok to proceed even if the memory was 775 * not onlined in time. 776 */ 777 wait_for_completion_timeout(&dm_device.ol_waitevent, 5 * HZ); 778 post_status(&dm_device); 779 } 780} 781 782static void hv_online_page(struct page *pg, unsigned int order) 783{ 784 struct hv_hotadd_state *has; 785 unsigned long pfn = page_to_pfn(pg); 786 787 guard(spinlock_irqsave)(&dm_device.ha_lock); 788 list_for_each_entry(has, &dm_device.ha_region_list, list) { 789 /* The page belongs to a different HAS. */ 790 if ((pfn < has->start_pfn) || 791 (pfn + (1UL << order) > has->end_pfn)) 792 continue; 793 794 hv_bring_pgs_online(has, pfn, 1UL << order); 795 break; 796 } 797} 798 799static int pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt) 800{ 801 struct hv_hotadd_state *has; 802 struct hv_hotadd_gap *gap; 803 unsigned long residual, new_inc; 804 int ret = 0; 805 806 guard(spinlock_irqsave)(&dm_device.ha_lock); 807 list_for_each_entry(has, &dm_device.ha_region_list, list) { 808 /* 809 * If the pfn range we are dealing with is not in the current 810 * "hot add block", move on. 811 */ 812 if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn) 813 continue; 814 815 /* 816 * If the current start pfn is not where the covered_end 817 * is, create a gap and update covered_end_pfn. 818 */ 819 if (has->covered_end_pfn != start_pfn) { 820 gap = kzalloc(sizeof(struct hv_hotadd_gap), GFP_ATOMIC); 821 if (!gap) { 822 ret = -ENOMEM; 823 break; 824 } 825 826 INIT_LIST_HEAD(&gap->list); 827 gap->start_pfn = has->covered_end_pfn; 828 gap->end_pfn = start_pfn; 829 list_add_tail(&gap->list, &has->gap_list); 830 831 has->covered_end_pfn = start_pfn; 832 } 833 834 /* 835 * If the current hot add-request extends beyond 836 * our current limit; extend it. 837 */ 838 if ((start_pfn + pfn_cnt) > has->end_pfn) { 839 residual = (start_pfn + pfn_cnt - has->end_pfn); 840 /* 841 * Extend the region by multiples of HA_CHUNK. 842 */ 843 new_inc = (residual / HA_CHUNK) * HA_CHUNK; 844 if (residual % HA_CHUNK) 845 new_inc += HA_CHUNK; 846 847 has->end_pfn += new_inc; 848 } 849 850 ret = 1; 851 break; 852 } 853 854 return ret; 855} 856 857static unsigned long handle_pg_range(unsigned long pg_start, 858 unsigned long pg_count) 859{ 860 unsigned long start_pfn = pg_start; 861 unsigned long pfn_cnt = pg_count; 862 unsigned long size; 863 struct hv_hotadd_state *has; 864 unsigned long pgs_ol = 0; 865 unsigned long old_covered_state; 866 unsigned long res = 0, flags; 867 868 pr_debug("Hot adding %lu pages starting at pfn 0x%lx.\n", pg_count, 869 pg_start); 870 871 spin_lock_irqsave(&dm_device.ha_lock, flags); 872 list_for_each_entry(has, &dm_device.ha_region_list, list) { 873 /* 874 * If the pfn range we are dealing with is not in the current 875 * "hot add block", move on. 876 */ 877 if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn) 878 continue; 879 880 old_covered_state = has->covered_end_pfn; 881 882 if (start_pfn < has->ha_end_pfn) { 883 /* 884 * This is the case where we are backing pages 885 * in an already hot added region. Bring 886 * these pages online first. 887 */ 888 pgs_ol = has->ha_end_pfn - start_pfn; 889 if (pgs_ol > pfn_cnt) 890 pgs_ol = pfn_cnt; 891 892 has->covered_end_pfn += pgs_ol; 893 pfn_cnt -= pgs_ol; 894 /* 895 * Check if the corresponding memory block is already 896 * online. It is possible to observe struct pages still 897 * being uninitialized here so check section instead. 898 * In case the section is online we need to bring the 899 * rest of pfns (which were not backed previously) 900 * online too. 901 */ 902 if (start_pfn > has->start_pfn && 903 online_section_nr(pfn_to_section_nr(start_pfn))) 904 hv_bring_pgs_online(has, start_pfn, pgs_ol); 905 906 } 907 908 if ((has->ha_end_pfn < has->end_pfn) && (pfn_cnt > 0)) { 909 /* 910 * We have some residual hot add range 911 * that needs to be hot added; hot add 912 * it now. Hot add a multiple of 913 * HA_CHUNK that fully covers the pages 914 * we have. 915 */ 916 size = (has->end_pfn - has->ha_end_pfn); 917 if (pfn_cnt <= size) { 918 size = ((pfn_cnt / HA_CHUNK) * HA_CHUNK); 919 if (pfn_cnt % HA_CHUNK) 920 size += HA_CHUNK; 921 } else { 922 pfn_cnt = size; 923 } 924 spin_unlock_irqrestore(&dm_device.ha_lock, flags); 925 hv_mem_hot_add(has->ha_end_pfn, size, pfn_cnt, has); 926 spin_lock_irqsave(&dm_device.ha_lock, flags); 927 } 928 /* 929 * If we managed to online any pages that were given to us, 930 * we declare success. 931 */ 932 res = has->covered_end_pfn - old_covered_state; 933 break; 934 } 935 spin_unlock_irqrestore(&dm_device.ha_lock, flags); 936 937 return res; 938} 939 940static unsigned long process_hot_add(unsigned long pg_start, 941 unsigned long pfn_cnt, 942 unsigned long rg_start, 943 unsigned long rg_size) 944{ 945 struct hv_hotadd_state *ha_region = NULL; 946 int covered; 947 948 if (pfn_cnt == 0) 949 return 0; 950 951 if (!dm_device.host_specified_ha_region) { 952 covered = pfn_covered(pg_start, pfn_cnt); 953 if (covered < 0) 954 return 0; 955 956 if (covered) 957 goto do_pg_range; 958 } 959 960 /* 961 * If the host has specified a hot-add range; deal with it first. 962 */ 963 964 if (rg_size != 0) { 965 ha_region = kzalloc(sizeof(struct hv_hotadd_state), GFP_KERNEL); 966 if (!ha_region) 967 return 0; 968 969 INIT_LIST_HEAD(&ha_region->list); 970 INIT_LIST_HEAD(&ha_region->gap_list); 971 972 ha_region->start_pfn = rg_start; 973 ha_region->ha_end_pfn = rg_start; 974 ha_region->covered_start_pfn = pg_start; 975 ha_region->covered_end_pfn = pg_start; 976 ha_region->end_pfn = rg_start + rg_size; 977 978 scoped_guard(spinlock_irqsave, &dm_device.ha_lock) { 979 list_add_tail(&ha_region->list, &dm_device.ha_region_list); 980 } 981 } 982 983do_pg_range: 984 /* 985 * Process the page range specified; bringing them 986 * online if possible. 987 */ 988 return handle_pg_range(pg_start, pfn_cnt); 989} 990 991#endif 992 993static void hot_add_req(struct work_struct *dummy) 994{ 995 struct dm_hot_add_response resp; 996#ifdef CONFIG_MEMORY_HOTPLUG 997 unsigned long pg_start, pfn_cnt; 998 unsigned long rg_start, rg_sz; 999#endif 1000 struct hv_dynmem_device *dm = &dm_device; 1001 1002 memset(&resp, 0, sizeof(struct dm_hot_add_response)); 1003 resp.hdr.type = DM_MEM_HOT_ADD_RESPONSE; 1004 resp.hdr.size = sizeof(struct dm_hot_add_response); 1005 1006#ifdef CONFIG_MEMORY_HOTPLUG 1007 pg_start = dm->ha_wrk.ha_page_range.finfo.start_page; 1008 pfn_cnt = dm->ha_wrk.ha_page_range.finfo.page_cnt; 1009 1010 rg_start = dm->ha_wrk.ha_region_range.finfo.start_page; 1011 rg_sz = dm->ha_wrk.ha_region_range.finfo.page_cnt; 1012 1013 if ((rg_start == 0) && (!dm->host_specified_ha_region)) { 1014 unsigned long region_size; 1015 unsigned long region_start; 1016 1017 /* 1018 * The host has not specified the hot-add region. 1019 * Based on the hot-add page range being specified, 1020 * compute a hot-add region that can cover the pages 1021 * that need to be hot-added while ensuring the alignment 1022 * and size requirements of Linux as it relates to hot-add. 1023 */ 1024 region_size = (pfn_cnt / HA_CHUNK) * HA_CHUNK; 1025 if (pfn_cnt % HA_CHUNK) 1026 region_size += HA_CHUNK; 1027 1028 region_start = (pg_start / HA_CHUNK) * HA_CHUNK; 1029 1030 rg_start = region_start; 1031 rg_sz = region_size; 1032 } 1033 1034 if (do_hot_add) 1035 resp.page_count = process_hot_add(pg_start, pfn_cnt, 1036 rg_start, rg_sz); 1037 1038 dm->num_pages_added += resp.page_count; 1039#endif 1040 /* 1041 * The result field of the response structure has the 1042 * following semantics: 1043 * 1044 * 1. If all or some pages hot-added: Guest should return success. 1045 * 1046 * 2. If no pages could be hot-added: 1047 * 1048 * If the guest returns success, then the host 1049 * will not attempt any further hot-add operations. This 1050 * signifies a permanent failure. 1051 * 1052 * If the guest returns failure, then this failure will be 1053 * treated as a transient failure and the host may retry the 1054 * hot-add operation after some delay. 1055 */ 1056 if (resp.page_count > 0) 1057 resp.result = 1; 1058 else if (!do_hot_add) 1059 resp.result = 1; 1060 else 1061 resp.result = 0; 1062 1063 if (!do_hot_add || resp.page_count == 0) { 1064 if (!allow_hibernation) 1065 pr_err("Memory hot add failed\n"); 1066 else 1067 pr_info("Ignore hot-add request!\n"); 1068 } 1069 1070 dm->state = DM_INITIALIZED; 1071 resp.hdr.trans_id = atomic_inc_return(&trans_id); 1072 vmbus_sendpacket(dm->dev->channel, &resp, 1073 sizeof(struct dm_hot_add_response), 1074 (unsigned long)NULL, 1075 VM_PKT_DATA_INBAND, 0); 1076} 1077 1078static void process_info(struct hv_dynmem_device *dm, struct dm_info_msg *msg) 1079{ 1080 struct dm_info_header *info_hdr; 1081 1082 info_hdr = (struct dm_info_header *)msg->info; 1083 1084 switch (info_hdr->type) { 1085 case INFO_TYPE_MAX_PAGE_CNT: 1086 if (info_hdr->data_size == sizeof(__u64)) { 1087 __u64 *max_page_count = (__u64 *)&info_hdr[1]; 1088 1089 pr_info("Max. dynamic memory size: %llu MB\n", 1090 (*max_page_count) >> (20 - HV_HYP_PAGE_SHIFT)); 1091 dm->max_dynamic_page_count = *max_page_count; 1092 } 1093 1094 break; 1095 default: 1096 pr_warn("Received Unknown type: %d\n", info_hdr->type); 1097 } 1098} 1099 1100static unsigned long compute_balloon_floor(void) 1101{ 1102 unsigned long min_pages; 1103 unsigned long nr_pages = totalram_pages(); 1104#define MB2PAGES(mb) ((mb) << (20 - PAGE_SHIFT)) 1105 /* Simple continuous piecewiese linear function: 1106 * max MiB -> min MiB gradient 1107 * 0 0 1108 * 16 16 1109 * 32 24 1110 * 128 72 (1/2) 1111 * 512 168 (1/4) 1112 * 2048 360 (1/8) 1113 * 8192 744 (1/16) 1114 * 32768 1512 (1/32) 1115 */ 1116 if (nr_pages < MB2PAGES(128)) 1117 min_pages = MB2PAGES(8) + (nr_pages >> 1); 1118 else if (nr_pages < MB2PAGES(512)) 1119 min_pages = MB2PAGES(40) + (nr_pages >> 2); 1120 else if (nr_pages < MB2PAGES(2048)) 1121 min_pages = MB2PAGES(104) + (nr_pages >> 3); 1122 else if (nr_pages < MB2PAGES(8192)) 1123 min_pages = MB2PAGES(232) + (nr_pages >> 4); 1124 else 1125 min_pages = MB2PAGES(488) + (nr_pages >> 5); 1126#undef MB2PAGES 1127 return min_pages; 1128} 1129 1130/* 1131 * Compute total committed memory pages 1132 */ 1133 1134static unsigned long get_pages_committed(struct hv_dynmem_device *dm) 1135{ 1136 return vm_memory_committed() + 1137 dm->num_pages_ballooned + 1138 (dm->num_pages_added > dm->num_pages_onlined ? 1139 dm->num_pages_added - dm->num_pages_onlined : 0) + 1140 compute_balloon_floor(); 1141} 1142 1143/* 1144 * Post our status as it relates memory pressure to the 1145 * host. Host expects the guests to post this status 1146 * periodically at 1 second intervals. 1147 * 1148 * The metrics specified in this protocol are very Windows 1149 * specific and so we cook up numbers here to convey our memory 1150 * pressure. 1151 */ 1152 1153static void post_status(struct hv_dynmem_device *dm) 1154{ 1155 struct dm_status status; 1156 unsigned long now = jiffies; 1157 unsigned long last_post = last_post_time; 1158 unsigned long num_pages_avail, num_pages_committed; 1159 1160 if (pressure_report_delay > 0) { 1161 --pressure_report_delay; 1162 return; 1163 } 1164 1165 if (!time_after(now, (last_post_time + HZ))) 1166 return; 1167 1168 memset(&status, 0, sizeof(struct dm_status)); 1169 status.hdr.type = DM_STATUS_REPORT; 1170 status.hdr.size = sizeof(struct dm_status); 1171 status.hdr.trans_id = atomic_inc_return(&trans_id); 1172 1173 /* 1174 * The host expects the guest to report free and committed memory. 1175 * Furthermore, the host expects the pressure information to include 1176 * the ballooned out pages. For a given amount of memory that we are 1177 * managing we need to compute a floor below which we should not 1178 * balloon. Compute this and add it to the pressure report. 1179 * We also need to report all offline pages (num_pages_added - 1180 * num_pages_onlined) as committed to the host, otherwise it can try 1181 * asking us to balloon them out. 1182 */ 1183 num_pages_avail = si_mem_available(); 1184 num_pages_committed = get_pages_committed(dm); 1185 1186 trace_balloon_status(num_pages_avail, num_pages_committed, 1187 vm_memory_committed(), dm->num_pages_ballooned, 1188 dm->num_pages_added, dm->num_pages_onlined); 1189 1190 /* Convert numbers of pages into numbers of HV_HYP_PAGEs. */ 1191 status.num_avail = num_pages_avail * NR_HV_HYP_PAGES_IN_PAGE; 1192 status.num_committed = num_pages_committed * NR_HV_HYP_PAGES_IN_PAGE; 1193 1194 /* 1195 * If our transaction ID is no longer current, just don't 1196 * send the status. This can happen if we were interrupted 1197 * after we picked our transaction ID. 1198 */ 1199 if (status.hdr.trans_id != atomic_read(&trans_id)) 1200 return; 1201 1202 /* 1203 * If the last post time that we sampled has changed, 1204 * we have raced, don't post the status. 1205 */ 1206 if (last_post != last_post_time) 1207 return; 1208 1209 last_post_time = jiffies; 1210 vmbus_sendpacket(dm->dev->channel, &status, 1211 sizeof(struct dm_status), 1212 (unsigned long)NULL, 1213 VM_PKT_DATA_INBAND, 0); 1214 1215} 1216 1217static void free_balloon_pages(struct hv_dynmem_device *dm, 1218 union dm_mem_page_range *range_array) 1219{ 1220 int num_pages = range_array->finfo.page_cnt; 1221 __u64 start_frame = range_array->finfo.start_page; 1222 struct page *pg; 1223 int i; 1224 1225 for (i = 0; i < num_pages; i++) { 1226 pg = pfn_to_page(i + start_frame); 1227 __ClearPageOffline(pg); 1228 __free_page(pg); 1229 dm->num_pages_ballooned--; 1230 adjust_managed_page_count(pg, 1); 1231 } 1232} 1233 1234 1235 1236static unsigned int alloc_balloon_pages(struct hv_dynmem_device *dm, 1237 unsigned int num_pages, 1238 struct dm_balloon_response *bl_resp, 1239 int alloc_unit) 1240{ 1241 unsigned int i, j; 1242 struct page *pg; 1243 1244 for (i = 0; i < num_pages / alloc_unit; i++) { 1245 if (bl_resp->hdr.size + sizeof(union dm_mem_page_range) > 1246 HV_HYP_PAGE_SIZE) 1247 return i * alloc_unit; 1248 1249 /* 1250 * We execute this code in a thread context. Furthermore, 1251 * we don't want the kernel to try too hard. 1252 */ 1253 pg = alloc_pages(GFP_HIGHUSER | __GFP_NORETRY | 1254 __GFP_NOMEMALLOC | __GFP_NOWARN, 1255 get_order(alloc_unit << PAGE_SHIFT)); 1256 1257 if (!pg) 1258 return i * alloc_unit; 1259 1260 dm->num_pages_ballooned += alloc_unit; 1261 1262 /* 1263 * If we allocatted 2M pages; split them so we 1264 * can free them in any order we get. 1265 */ 1266 1267 if (alloc_unit != 1) 1268 split_page(pg, get_order(alloc_unit << PAGE_SHIFT)); 1269 1270 /* mark all pages offline */ 1271 for (j = 0; j < alloc_unit; j++) { 1272 __SetPageOffline(pg + j); 1273 adjust_managed_page_count(pg + j, -1); 1274 } 1275 1276 bl_resp->range_count++; 1277 bl_resp->range_array[i].finfo.start_page = 1278 page_to_pfn(pg); 1279 bl_resp->range_array[i].finfo.page_cnt = alloc_unit; 1280 bl_resp->hdr.size += sizeof(union dm_mem_page_range); 1281 1282 } 1283 1284 return i * alloc_unit; 1285} 1286 1287static void balloon_up(struct work_struct *dummy) 1288{ 1289 unsigned int num_pages = dm_device.balloon_wrk.num_pages; 1290 unsigned int num_ballooned = 0; 1291 struct dm_balloon_response *bl_resp; 1292 int alloc_unit; 1293 int ret; 1294 bool done = false; 1295 int i; 1296 long avail_pages; 1297 unsigned long floor; 1298 1299 /* 1300 * We will attempt 2M allocations. However, if we fail to 1301 * allocate 2M chunks, we will go back to PAGE_SIZE allocations. 1302 */ 1303 alloc_unit = PAGES_IN_2M; 1304 1305 avail_pages = si_mem_available(); 1306 floor = compute_balloon_floor(); 1307 1308 /* Refuse to balloon below the floor. */ 1309 if (avail_pages < num_pages || avail_pages - num_pages < floor) { 1310 pr_info("Balloon request will be partially fulfilled. %s\n", 1311 avail_pages < num_pages ? "Not enough memory." : 1312 "Balloon floor reached."); 1313 1314 num_pages = avail_pages > floor ? (avail_pages - floor) : 0; 1315 } 1316 1317 while (!done) { 1318 memset(balloon_up_send_buffer, 0, HV_HYP_PAGE_SIZE); 1319 bl_resp = (struct dm_balloon_response *)balloon_up_send_buffer; 1320 bl_resp->hdr.type = DM_BALLOON_RESPONSE; 1321 bl_resp->hdr.size = sizeof(struct dm_balloon_response); 1322 bl_resp->more_pages = 1; 1323 1324 num_pages -= num_ballooned; 1325 num_ballooned = alloc_balloon_pages(&dm_device, num_pages, 1326 bl_resp, alloc_unit); 1327 1328 if (alloc_unit != 1 && num_ballooned == 0) { 1329 alloc_unit = 1; 1330 continue; 1331 } 1332 1333 if (num_ballooned == 0 || num_ballooned == num_pages) { 1334 pr_debug("Ballooned %u out of %u requested pages.\n", 1335 num_pages, dm_device.balloon_wrk.num_pages); 1336 1337 bl_resp->more_pages = 0; 1338 done = true; 1339 dm_device.state = DM_INITIALIZED; 1340 } 1341 1342 /* 1343 * We are pushing a lot of data through the channel; 1344 * deal with transient failures caused because of the 1345 * lack of space in the ring buffer. 1346 */ 1347 1348 do { 1349 bl_resp->hdr.trans_id = atomic_inc_return(&trans_id); 1350 ret = vmbus_sendpacket(dm_device.dev->channel, 1351 bl_resp, 1352 bl_resp->hdr.size, 1353 (unsigned long)NULL, 1354 VM_PKT_DATA_INBAND, 0); 1355 1356 if (ret == -EAGAIN) 1357 msleep(20); 1358 post_status(&dm_device); 1359 } while (ret == -EAGAIN); 1360 1361 if (ret) { 1362 /* 1363 * Free up the memory we allocatted. 1364 */ 1365 pr_err("Balloon response failed\n"); 1366 1367 for (i = 0; i < bl_resp->range_count; i++) 1368 free_balloon_pages(&dm_device, 1369 &bl_resp->range_array[i]); 1370 1371 done = true; 1372 } 1373 } 1374 1375} 1376 1377static void balloon_down(struct hv_dynmem_device *dm, 1378 struct dm_unballoon_request *req) 1379{ 1380 union dm_mem_page_range *range_array = req->range_array; 1381 int range_count = req->range_count; 1382 struct dm_unballoon_response resp; 1383 int i; 1384 unsigned int prev_pages_ballooned = dm->num_pages_ballooned; 1385 1386 for (i = 0; i < range_count; i++) { 1387 free_balloon_pages(dm, &range_array[i]); 1388 complete(&dm_device.config_event); 1389 } 1390 1391 pr_debug("Freed %u ballooned pages.\n", 1392 prev_pages_ballooned - dm->num_pages_ballooned); 1393 1394 if (req->more_pages == 1) 1395 return; 1396 1397 memset(&resp, 0, sizeof(struct dm_unballoon_response)); 1398 resp.hdr.type = DM_UNBALLOON_RESPONSE; 1399 resp.hdr.trans_id = atomic_inc_return(&trans_id); 1400 resp.hdr.size = sizeof(struct dm_unballoon_response); 1401 1402 vmbus_sendpacket(dm_device.dev->channel, &resp, 1403 sizeof(struct dm_unballoon_response), 1404 (unsigned long)NULL, 1405 VM_PKT_DATA_INBAND, 0); 1406 1407 dm->state = DM_INITIALIZED; 1408} 1409 1410static void balloon_onchannelcallback(void *context); 1411 1412static int dm_thread_func(void *dm_dev) 1413{ 1414 struct hv_dynmem_device *dm = dm_dev; 1415 1416 while (!kthread_should_stop()) { 1417 wait_for_completion_interruptible_timeout( 1418 &dm_device.config_event, 1*HZ); 1419 /* 1420 * The host expects us to post information on the memory 1421 * pressure every second. 1422 */ 1423 reinit_completion(&dm_device.config_event); 1424 post_status(dm); 1425 /* 1426 * disable free page reporting if multiple hypercall 1427 * failure flag set. It is not done in the page_reporting 1428 * callback context as that causes a deadlock between 1429 * page_reporting_process() and page_reporting_unregister() 1430 */ 1431 if (hv_hypercall_multi_failure >= HV_MAX_FAILURES) { 1432 pr_err("Multiple failures in cold memory discard hypercall, disabling page reporting\n"); 1433 disable_page_reporting(); 1434 /* Reset the flag after disabling reporting */ 1435 hv_hypercall_multi_failure = 0; 1436 } 1437 } 1438 1439 return 0; 1440} 1441 1442 1443static void version_resp(struct hv_dynmem_device *dm, 1444 struct dm_version_response *vresp) 1445{ 1446 struct dm_version_request version_req; 1447 int ret; 1448 1449 if (vresp->is_accepted) { 1450 /* 1451 * We are done; wakeup the 1452 * context waiting for version 1453 * negotiation. 1454 */ 1455 complete(&dm->host_event); 1456 return; 1457 } 1458 /* 1459 * If there are more versions to try, continue 1460 * with negotiations; if not 1461 * shutdown the service since we are not able 1462 * to negotiate a suitable version number 1463 * with the host. 1464 */ 1465 if (dm->next_version == 0) 1466 goto version_error; 1467 1468 memset(&version_req, 0, sizeof(struct dm_version_request)); 1469 version_req.hdr.type = DM_VERSION_REQUEST; 1470 version_req.hdr.size = sizeof(struct dm_version_request); 1471 version_req.hdr.trans_id = atomic_inc_return(&trans_id); 1472 version_req.version.version = dm->next_version; 1473 dm->version = version_req.version.version; 1474 1475 /* 1476 * Set the next version to try in case current version fails. 1477 * Win7 protocol ought to be the last one to try. 1478 */ 1479 switch (version_req.version.version) { 1480 case DYNMEM_PROTOCOL_VERSION_WIN8: 1481 dm->next_version = DYNMEM_PROTOCOL_VERSION_WIN7; 1482 version_req.is_last_attempt = 0; 1483 break; 1484 default: 1485 dm->next_version = 0; 1486 version_req.is_last_attempt = 1; 1487 } 1488 1489 ret = vmbus_sendpacket(dm->dev->channel, &version_req, 1490 sizeof(struct dm_version_request), 1491 (unsigned long)NULL, 1492 VM_PKT_DATA_INBAND, 0); 1493 1494 if (ret) 1495 goto version_error; 1496 1497 return; 1498 1499version_error: 1500 dm->state = DM_INIT_ERROR; 1501 complete(&dm->host_event); 1502} 1503 1504static void cap_resp(struct hv_dynmem_device *dm, 1505 struct dm_capabilities_resp_msg *cap_resp) 1506{ 1507 if (!cap_resp->is_accepted) { 1508 pr_err("Capabilities not accepted by host\n"); 1509 dm->state = DM_INIT_ERROR; 1510 } 1511 complete(&dm->host_event); 1512} 1513 1514static void balloon_onchannelcallback(void *context) 1515{ 1516 struct hv_device *dev = context; 1517 u32 recvlen; 1518 u64 requestid; 1519 struct dm_message *dm_msg; 1520 struct dm_header *dm_hdr; 1521 struct hv_dynmem_device *dm = hv_get_drvdata(dev); 1522 struct dm_balloon *bal_msg; 1523 struct dm_hot_add *ha_msg; 1524 union dm_mem_page_range *ha_pg_range; 1525 union dm_mem_page_range *ha_region; 1526 1527 memset(recv_buffer, 0, sizeof(recv_buffer)); 1528 vmbus_recvpacket(dev->channel, recv_buffer, 1529 HV_HYP_PAGE_SIZE, &recvlen, &requestid); 1530 1531 if (recvlen > 0) { 1532 dm_msg = (struct dm_message *)recv_buffer; 1533 dm_hdr = &dm_msg->hdr; 1534 1535 switch (dm_hdr->type) { 1536 case DM_VERSION_RESPONSE: 1537 version_resp(dm, 1538 (struct dm_version_response *)dm_msg); 1539 break; 1540 1541 case DM_CAPABILITIES_RESPONSE: 1542 cap_resp(dm, 1543 (struct dm_capabilities_resp_msg *)dm_msg); 1544 break; 1545 1546 case DM_BALLOON_REQUEST: 1547 if (allow_hibernation) { 1548 pr_info("Ignore balloon-up request!\n"); 1549 break; 1550 } 1551 1552 if (dm->state == DM_BALLOON_UP) 1553 pr_warn("Currently ballooning\n"); 1554 bal_msg = (struct dm_balloon *)recv_buffer; 1555 dm->state = DM_BALLOON_UP; 1556 dm_device.balloon_wrk.num_pages = bal_msg->num_pages; 1557 schedule_work(&dm_device.balloon_wrk.wrk); 1558 break; 1559 1560 case DM_UNBALLOON_REQUEST: 1561 if (allow_hibernation) { 1562 pr_info("Ignore balloon-down request!\n"); 1563 break; 1564 } 1565 1566 dm->state = DM_BALLOON_DOWN; 1567 balloon_down(dm, 1568 (struct dm_unballoon_request *)recv_buffer); 1569 break; 1570 1571 case DM_MEM_HOT_ADD_REQUEST: 1572 if (dm->state == DM_HOT_ADD) 1573 pr_warn("Currently hot-adding\n"); 1574 dm->state = DM_HOT_ADD; 1575 ha_msg = (struct dm_hot_add *)recv_buffer; 1576 if (ha_msg->hdr.size == sizeof(struct dm_hot_add)) { 1577 /* 1578 * This is a normal hot-add request specifying 1579 * hot-add memory. 1580 */ 1581 dm->host_specified_ha_region = false; 1582 ha_pg_range = &ha_msg->range; 1583 dm->ha_wrk.ha_page_range = *ha_pg_range; 1584 dm->ha_wrk.ha_region_range.page_range = 0; 1585 } else { 1586 /* 1587 * Host is specifying that we first hot-add 1588 * a region and then partially populate this 1589 * region. 1590 */ 1591 dm->host_specified_ha_region = true; 1592 ha_pg_range = &ha_msg->range; 1593 ha_region = &ha_pg_range[1]; 1594 dm->ha_wrk.ha_page_range = *ha_pg_range; 1595 dm->ha_wrk.ha_region_range = *ha_region; 1596 } 1597 schedule_work(&dm_device.ha_wrk.wrk); 1598 break; 1599 1600 case DM_INFO_MESSAGE: 1601 process_info(dm, (struct dm_info_msg *)dm_msg); 1602 break; 1603 1604 default: 1605 pr_warn_ratelimited("Unhandled message: type: %d\n", dm_hdr->type); 1606 1607 } 1608 } 1609 1610} 1611 1612#define HV_LARGE_REPORTING_ORDER 9 1613#define HV_LARGE_REPORTING_LEN (HV_HYP_PAGE_SIZE << \ 1614 HV_LARGE_REPORTING_ORDER) 1615static int hv_free_page_report(struct page_reporting_dev_info *pr_dev_info, 1616 struct scatterlist *sgl, unsigned int nents) 1617{ 1618 unsigned long flags; 1619 struct hv_memory_hint *hint; 1620 int i, order; 1621 u64 status; 1622 struct scatterlist *sg; 1623 1624 WARN_ON_ONCE(nents > HV_MEMORY_HINT_MAX_GPA_PAGE_RANGES); 1625 WARN_ON_ONCE(sgl->length < (HV_HYP_PAGE_SIZE << page_reporting_order)); 1626 local_irq_save(flags); 1627 hint = *this_cpu_ptr(hyperv_pcpu_input_arg); 1628 if (!hint) { 1629 local_irq_restore(flags); 1630 return -ENOSPC; 1631 } 1632 1633 hint->type = HV_EXT_MEMORY_HEAT_HINT_TYPE_COLD_DISCARD; 1634 hint->reserved = 0; 1635 for_each_sg(sgl, sg, nents, i) { 1636 union hv_gpa_page_range *range; 1637 1638 range = &hint->ranges[i]; 1639 range->address_space = 0; 1640 order = get_order(sg->length); 1641 /* 1642 * Hyper-V expects the additional_pages field in the units 1643 * of one of these 3 sizes, 4Kbytes, 2Mbytes or 1Gbytes. 1644 * This is dictated by the values of the fields page.largesize 1645 * and page_size. 1646 * This code however, only uses 4Kbytes and 2Mbytes units 1647 * and not 1Gbytes unit. 1648 */ 1649 1650 /* page reporting for pages 2MB or higher */ 1651 if (order >= HV_LARGE_REPORTING_ORDER ) { 1652 range->page.largepage = 1; 1653 range->page_size = HV_GPA_PAGE_RANGE_PAGE_SIZE_2MB; 1654 range->base_large_pfn = page_to_hvpfn( 1655 sg_page(sg)) >> HV_LARGE_REPORTING_ORDER; 1656 range->page.additional_pages = 1657 (sg->length / HV_LARGE_REPORTING_LEN) - 1; 1658 } else { 1659 /* Page reporting for pages below 2MB */ 1660 range->page.basepfn = page_to_hvpfn(sg_page(sg)); 1661 range->page.largepage = false; 1662 range->page.additional_pages = 1663 (sg->length / HV_HYP_PAGE_SIZE) - 1; 1664 } 1665 1666 } 1667 1668 status = hv_do_rep_hypercall(HV_EXT_CALL_MEMORY_HEAT_HINT, nents, 0, 1669 hint, NULL); 1670 local_irq_restore(flags); 1671 if (!hv_result_success(status)) { 1672 1673 pr_err("Cold memory discard hypercall failed with status %llx\n", 1674 status); 1675 if (hv_hypercall_multi_failure > 0) 1676 hv_hypercall_multi_failure++; 1677 1678 if (hv_result(status) == HV_STATUS_INVALID_PARAMETER) { 1679 pr_err("Underlying Hyper-V does not support order less than 9. Hypercall failed\n"); 1680 pr_err("Defaulting to page_reporting_order %d\n", 1681 pageblock_order); 1682 page_reporting_order = pageblock_order; 1683 hv_hypercall_multi_failure++; 1684 return -EINVAL; 1685 } 1686 1687 return -EINVAL; 1688 } 1689 1690 return 0; 1691} 1692 1693static void enable_page_reporting(void) 1694{ 1695 int ret; 1696 1697 if (!hv_query_ext_cap(HV_EXT_CAPABILITY_MEMORY_COLD_DISCARD_HINT)) { 1698 pr_debug("Cold memory discard hint not supported by Hyper-V\n"); 1699 return; 1700 } 1701 1702 BUILD_BUG_ON(PAGE_REPORTING_CAPACITY > HV_MEMORY_HINT_MAX_GPA_PAGE_RANGES); 1703 dm_device.pr_dev_info.report = hv_free_page_report; 1704 /* 1705 * We let the page_reporting_order parameter decide the order 1706 * in the page_reporting code 1707 */ 1708 dm_device.pr_dev_info.order = 0; 1709 ret = page_reporting_register(&dm_device.pr_dev_info); 1710 if (ret < 0) { 1711 dm_device.pr_dev_info.report = NULL; 1712 pr_err("Failed to enable cold memory discard: %d\n", ret); 1713 } else { 1714 pr_info("Cold memory discard hint enabled with order %d\n", 1715 page_reporting_order); 1716 } 1717} 1718 1719static void disable_page_reporting(void) 1720{ 1721 if (dm_device.pr_dev_info.report) { 1722 page_reporting_unregister(&dm_device.pr_dev_info); 1723 dm_device.pr_dev_info.report = NULL; 1724 } 1725} 1726 1727static int ballooning_enabled(void) 1728{ 1729 /* 1730 * Disable ballooning if the page size is not 4k (HV_HYP_PAGE_SIZE), 1731 * since currently it's unclear to us whether an unballoon request can 1732 * make sure all page ranges are guest page size aligned. 1733 */ 1734 if (PAGE_SIZE != HV_HYP_PAGE_SIZE) { 1735 pr_info("Ballooning disabled because page size is not 4096 bytes\n"); 1736 return 0; 1737 } 1738 1739 return 1; 1740} 1741 1742static int hot_add_enabled(void) 1743{ 1744 /* 1745 * Disable hot add on ARM64, because we currently rely on 1746 * memory_add_physaddr_to_nid() to get a node id of a hot add range, 1747 * however ARM64's memory_add_physaddr_to_nid() always return 0 and 1748 * DM_MEM_HOT_ADD_REQUEST doesn't have the NUMA node information for 1749 * add_memory(). 1750 */ 1751 if (IS_ENABLED(CONFIG_ARM64)) { 1752 pr_info("Memory hot add disabled on ARM64\n"); 1753 return 0; 1754 } 1755 1756 return 1; 1757} 1758 1759static int balloon_connect_vsp(struct hv_device *dev) 1760{ 1761 struct dm_version_request version_req; 1762 struct dm_capabilities cap_msg; 1763 unsigned long t; 1764 int ret; 1765 1766 /* 1767 * max_pkt_size should be large enough for one vmbus packet header plus 1768 * our receive buffer size. Hyper-V sends messages up to 1769 * HV_HYP_PAGE_SIZE bytes long on balloon channel. 1770 */ 1771 dev->channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2; 1772 1773 ret = vmbus_open(dev->channel, dm_ring_size, dm_ring_size, NULL, 0, 1774 balloon_onchannelcallback, dev); 1775 if (ret) 1776 return ret; 1777 1778 /* 1779 * Initiate the hand shake with the host and negotiate 1780 * a version that the host can support. We start with the 1781 * highest version number and go down if the host cannot 1782 * support it. 1783 */ 1784 memset(&version_req, 0, sizeof(struct dm_version_request)); 1785 version_req.hdr.type = DM_VERSION_REQUEST; 1786 version_req.hdr.size = sizeof(struct dm_version_request); 1787 version_req.hdr.trans_id = atomic_inc_return(&trans_id); 1788 version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN10; 1789 version_req.is_last_attempt = 0; 1790 dm_device.version = version_req.version.version; 1791 1792 ret = vmbus_sendpacket(dev->channel, &version_req, 1793 sizeof(struct dm_version_request), 1794 (unsigned long)NULL, VM_PKT_DATA_INBAND, 0); 1795 if (ret) 1796 goto out; 1797 1798 t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ); 1799 if (t == 0) { 1800 ret = -ETIMEDOUT; 1801 goto out; 1802 } 1803 1804 /* 1805 * If we could not negotiate a compatible version with the host 1806 * fail the probe function. 1807 */ 1808 if (dm_device.state == DM_INIT_ERROR) { 1809 ret = -EPROTO; 1810 goto out; 1811 } 1812 1813 pr_info("Using Dynamic Memory protocol version %u.%u\n", 1814 DYNMEM_MAJOR_VERSION(dm_device.version), 1815 DYNMEM_MINOR_VERSION(dm_device.version)); 1816 1817 /* 1818 * Now submit our capabilities to the host. 1819 */ 1820 memset(&cap_msg, 0, sizeof(struct dm_capabilities)); 1821 cap_msg.hdr.type = DM_CAPABILITIES_REPORT; 1822 cap_msg.hdr.size = sizeof(struct dm_capabilities); 1823 cap_msg.hdr.trans_id = atomic_inc_return(&trans_id); 1824 1825 /* 1826 * When hibernation (i.e. virtual ACPI S4 state) is enabled, the host 1827 * currently still requires the bits to be set, so we have to add code 1828 * to fail the host's hot-add and balloon up/down requests, if any. 1829 */ 1830 cap_msg.caps.cap_bits.balloon = ballooning_enabled(); 1831 cap_msg.caps.cap_bits.hot_add = hot_add_enabled(); 1832 1833 /* 1834 * Specify our alignment requirements as it relates 1835 * memory hot-add. Specify 128MB alignment. 1836 */ 1837 cap_msg.caps.cap_bits.hot_add_alignment = 7; 1838 1839 /* 1840 * Currently the host does not use these 1841 * values and we set them to what is done in the 1842 * Windows driver. 1843 */ 1844 cap_msg.min_page_cnt = 0; 1845 cap_msg.max_page_number = -1; 1846 1847 ret = vmbus_sendpacket(dev->channel, &cap_msg, 1848 sizeof(struct dm_capabilities), 1849 (unsigned long)NULL, VM_PKT_DATA_INBAND, 0); 1850 if (ret) 1851 goto out; 1852 1853 t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ); 1854 if (t == 0) { 1855 ret = -ETIMEDOUT; 1856 goto out; 1857 } 1858 1859 /* 1860 * If the host does not like our capabilities, 1861 * fail the probe function. 1862 */ 1863 if (dm_device.state == DM_INIT_ERROR) { 1864 ret = -EPROTO; 1865 goto out; 1866 } 1867 1868 return 0; 1869out: 1870 vmbus_close(dev->channel); 1871 return ret; 1872} 1873 1874/* 1875 * DEBUGFS Interface 1876 */ 1877#ifdef CONFIG_DEBUG_FS 1878 1879/** 1880 * hv_balloon_debug_show - shows statistics of balloon operations. 1881 * @f: pointer to the &struct seq_file. 1882 * @offset: ignored. 1883 * 1884 * Provides the statistics that can be accessed in hv-balloon in the debugfs. 1885 * 1886 * Return: zero on success or an error code. 1887 */ 1888static int hv_balloon_debug_show(struct seq_file *f, void *offset) 1889{ 1890 struct hv_dynmem_device *dm = f->private; 1891 char *sname; 1892 1893 seq_printf(f, "%-22s: %u.%u\n", "host_version", 1894 DYNMEM_MAJOR_VERSION(dm->version), 1895 DYNMEM_MINOR_VERSION(dm->version)); 1896 1897 seq_printf(f, "%-22s:", "capabilities"); 1898 if (ballooning_enabled()) 1899 seq_puts(f, " enabled"); 1900 1901 if (hot_add_enabled()) 1902 seq_puts(f, " hot_add"); 1903 1904 seq_puts(f, "\n"); 1905 1906 seq_printf(f, "%-22s: %u", "state", dm->state); 1907 switch (dm->state) { 1908 case DM_INITIALIZING: 1909 sname = "Initializing"; 1910 break; 1911 case DM_INITIALIZED: 1912 sname = "Initialized"; 1913 break; 1914 case DM_BALLOON_UP: 1915 sname = "Balloon Up"; 1916 break; 1917 case DM_BALLOON_DOWN: 1918 sname = "Balloon Down"; 1919 break; 1920 case DM_HOT_ADD: 1921 sname = "Hot Add"; 1922 break; 1923 case DM_INIT_ERROR: 1924 sname = "Error"; 1925 break; 1926 default: 1927 sname = "Unknown"; 1928 } 1929 seq_printf(f, " (%s)\n", sname); 1930 1931 /* HV Page Size */ 1932 seq_printf(f, "%-22s: %ld\n", "page_size", HV_HYP_PAGE_SIZE); 1933 1934 /* Pages added with hot_add */ 1935 seq_printf(f, "%-22s: %u\n", "pages_added", dm->num_pages_added); 1936 1937 /* pages that are "onlined"/used from pages_added */ 1938 seq_printf(f, "%-22s: %u\n", "pages_onlined", dm->num_pages_onlined); 1939 1940 /* pages we have given back to host */ 1941 seq_printf(f, "%-22s: %u\n", "pages_ballooned", dm->num_pages_ballooned); 1942 1943 seq_printf(f, "%-22s: %lu\n", "total_pages_committed", 1944 get_pages_committed(dm)); 1945 1946 seq_printf(f, "%-22s: %llu\n", "max_dynamic_page_count", 1947 dm->max_dynamic_page_count); 1948 1949 return 0; 1950} 1951 1952DEFINE_SHOW_ATTRIBUTE(hv_balloon_debug); 1953 1954static void hv_balloon_debugfs_init(struct hv_dynmem_device *b) 1955{ 1956 debugfs_create_file("hv-balloon", 0444, NULL, b, 1957 &hv_balloon_debug_fops); 1958} 1959 1960static void hv_balloon_debugfs_exit(struct hv_dynmem_device *b) 1961{ 1962 debugfs_lookup_and_remove("hv-balloon", NULL); 1963} 1964 1965#else 1966 1967static inline void hv_balloon_debugfs_init(struct hv_dynmem_device *b) 1968{ 1969} 1970 1971static inline void hv_balloon_debugfs_exit(struct hv_dynmem_device *b) 1972{ 1973} 1974 1975#endif /* CONFIG_DEBUG_FS */ 1976 1977static int balloon_probe(struct hv_device *dev, 1978 const struct hv_vmbus_device_id *dev_id) 1979{ 1980 int ret; 1981 1982 allow_hibernation = hv_is_hibernation_supported(); 1983 if (allow_hibernation) 1984 hot_add = false; 1985 1986#ifdef CONFIG_MEMORY_HOTPLUG 1987 do_hot_add = hot_add; 1988#else 1989 do_hot_add = false; 1990#endif 1991 dm_device.dev = dev; 1992 dm_device.state = DM_INITIALIZING; 1993 dm_device.next_version = DYNMEM_PROTOCOL_VERSION_WIN8; 1994 init_completion(&dm_device.host_event); 1995 init_completion(&dm_device.config_event); 1996 INIT_LIST_HEAD(&dm_device.ha_region_list); 1997 spin_lock_init(&dm_device.ha_lock); 1998 INIT_WORK(&dm_device.balloon_wrk.wrk, balloon_up); 1999 INIT_WORK(&dm_device.ha_wrk.wrk, hot_add_req); 2000 dm_device.host_specified_ha_region = false; 2001 2002#ifdef CONFIG_MEMORY_HOTPLUG 2003 set_online_page_callback(&hv_online_page); 2004 init_completion(&dm_device.ol_waitevent); 2005 register_memory_notifier(&hv_memory_nb); 2006#endif 2007 2008 hv_set_drvdata(dev, &dm_device); 2009 2010 ret = balloon_connect_vsp(dev); 2011 if (ret != 0) 2012 goto connect_error; 2013 2014 enable_page_reporting(); 2015 dm_device.state = DM_INITIALIZED; 2016 2017 dm_device.thread = 2018 kthread_run(dm_thread_func, &dm_device, "hv_balloon"); 2019 if (IS_ERR(dm_device.thread)) { 2020 ret = PTR_ERR(dm_device.thread); 2021 goto probe_error; 2022 } 2023 2024 hv_balloon_debugfs_init(&dm_device); 2025 2026 return 0; 2027 2028probe_error: 2029 dm_device.state = DM_INIT_ERROR; 2030 dm_device.thread = NULL; 2031 disable_page_reporting(); 2032 vmbus_close(dev->channel); 2033connect_error: 2034#ifdef CONFIG_MEMORY_HOTPLUG 2035 unregister_memory_notifier(&hv_memory_nb); 2036 restore_online_page_callback(&hv_online_page); 2037#endif 2038 return ret; 2039} 2040 2041static void balloon_remove(struct hv_device *dev) 2042{ 2043 struct hv_dynmem_device *dm = hv_get_drvdata(dev); 2044 struct hv_hotadd_state *has, *tmp; 2045 struct hv_hotadd_gap *gap, *tmp_gap; 2046 2047 if (dm->num_pages_ballooned != 0) 2048 pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned); 2049 2050 hv_balloon_debugfs_exit(dm); 2051 2052 cancel_work_sync(&dm->balloon_wrk.wrk); 2053 cancel_work_sync(&dm->ha_wrk.wrk); 2054 2055 kthread_stop(dm->thread); 2056 2057 /* 2058 * This is to handle the case when balloon_resume() 2059 * call has failed and some cleanup has been done as 2060 * a part of the error handling. 2061 */ 2062 if (dm_device.state != DM_INIT_ERROR) { 2063 disable_page_reporting(); 2064 vmbus_close(dev->channel); 2065#ifdef CONFIG_MEMORY_HOTPLUG 2066 unregister_memory_notifier(&hv_memory_nb); 2067 restore_online_page_callback(&hv_online_page); 2068#endif 2069 } 2070 2071 guard(spinlock_irqsave)(&dm_device.ha_lock); 2072 list_for_each_entry_safe(has, tmp, &dm->ha_region_list, list) { 2073 list_for_each_entry_safe(gap, tmp_gap, &has->gap_list, list) { 2074 list_del(&gap->list); 2075 kfree(gap); 2076 } 2077 list_del(&has->list); 2078 kfree(has); 2079 } 2080} 2081 2082static int balloon_suspend(struct hv_device *hv_dev) 2083{ 2084 struct hv_dynmem_device *dm = hv_get_drvdata(hv_dev); 2085 2086 tasklet_disable(&hv_dev->channel->callback_event); 2087 2088 cancel_work_sync(&dm->balloon_wrk.wrk); 2089 cancel_work_sync(&dm->ha_wrk.wrk); 2090 2091 if (dm->thread) { 2092 kthread_stop(dm->thread); 2093 dm->thread = NULL; 2094 vmbus_close(hv_dev->channel); 2095 } 2096 2097 tasklet_enable(&hv_dev->channel->callback_event); 2098 2099 return 0; 2100 2101} 2102 2103static int balloon_resume(struct hv_device *dev) 2104{ 2105 int ret; 2106 2107 dm_device.state = DM_INITIALIZING; 2108 2109 ret = balloon_connect_vsp(dev); 2110 2111 if (ret != 0) 2112 goto out; 2113 2114 dm_device.thread = 2115 kthread_run(dm_thread_func, &dm_device, "hv_balloon"); 2116 if (IS_ERR(dm_device.thread)) { 2117 ret = PTR_ERR(dm_device.thread); 2118 dm_device.thread = NULL; 2119 goto close_channel; 2120 } 2121 2122 dm_device.state = DM_INITIALIZED; 2123 return 0; 2124close_channel: 2125 vmbus_close(dev->channel); 2126out: 2127 dm_device.state = DM_INIT_ERROR; 2128 disable_page_reporting(); 2129#ifdef CONFIG_MEMORY_HOTPLUG 2130 unregister_memory_notifier(&hv_memory_nb); 2131 restore_online_page_callback(&hv_online_page); 2132#endif 2133 return ret; 2134} 2135 2136static const struct hv_vmbus_device_id id_table[] = { 2137 /* Dynamic Memory Class ID */ 2138 /* 525074DC-8985-46e2-8057-A307DC18A502 */ 2139 { HV_DM_GUID, }, 2140 { }, 2141}; 2142 2143MODULE_DEVICE_TABLE(vmbus, id_table); 2144 2145static struct hv_driver balloon_drv = { 2146 .name = "hv_balloon", 2147 .id_table = id_table, 2148 .probe = balloon_probe, 2149 .remove = balloon_remove, 2150 .suspend = balloon_suspend, 2151 .resume = balloon_resume, 2152 .driver = { 2153 .probe_type = PROBE_PREFER_ASYNCHRONOUS, 2154 }, 2155}; 2156 2157static int __init init_balloon_drv(void) 2158{ 2159 2160 return vmbus_driver_register(&balloon_drv); 2161} 2162 2163module_init(init_balloon_drv); 2164 2165MODULE_DESCRIPTION("Hyper-V Balloon"); 2166MODULE_LICENSE("GPL"); 2167