linux/drivers/hv/hv_balloon.c
<<
>>
Prefs
   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/mman.h>
  23#include <linux/delay.h>
  24#include <linux/init.h>
  25#include <linux/module.h>
  26#include <linux/slab.h>
  27#include <linux/kthread.h>
  28#include <linux/completion.h>
  29#include <linux/memory_hotplug.h>
  30#include <linux/memory.h>
  31#include <linux/notifier.h>
  32#include <linux/percpu_counter.h>
  33
  34#include <linux/hyperv.h>
  35
  36/*
  37 * We begin with definitions supporting the Dynamic Memory protocol
  38 * with the host.
  39 *
  40 * Begin protocol definitions.
  41 */
  42
  43
  44
  45/*
  46 * Protocol versions. The low word is the minor version, the high word the major
  47 * version.
  48 *
  49 * History:
  50 * Initial version 1.0
  51 * Changed to 0.1 on 2009/03/25
  52 * Changes to 0.2 on 2009/05/14
  53 * Changes to 0.3 on 2009/12/03
  54 * Changed to 1.0 on 2011/04/05
  55 */
  56
  57#define DYNMEM_MAKE_VERSION(Major, Minor) ((__u32)(((Major) << 16) | (Minor)))
  58#define DYNMEM_MAJOR_VERSION(Version) ((__u32)(Version) >> 16)
  59#define DYNMEM_MINOR_VERSION(Version) ((__u32)(Version) & 0xff)
  60
  61enum {
  62        DYNMEM_PROTOCOL_VERSION_1 = DYNMEM_MAKE_VERSION(0, 3),
  63        DYNMEM_PROTOCOL_VERSION_2 = DYNMEM_MAKE_VERSION(1, 0),
  64
  65        DYNMEM_PROTOCOL_VERSION_WIN7 = DYNMEM_PROTOCOL_VERSION_1,
  66        DYNMEM_PROTOCOL_VERSION_WIN8 = DYNMEM_PROTOCOL_VERSION_2,
  67
  68        DYNMEM_PROTOCOL_VERSION_CURRENT = DYNMEM_PROTOCOL_VERSION_WIN8
  69};
  70
  71
  72
  73/*
  74 * Message Types
  75 */
  76
  77enum dm_message_type {
  78        /*
  79         * Version 0.3
  80         */
  81        DM_ERROR                        = 0,
  82        DM_VERSION_REQUEST              = 1,
  83        DM_VERSION_RESPONSE             = 2,
  84        DM_CAPABILITIES_REPORT          = 3,
  85        DM_CAPABILITIES_RESPONSE        = 4,
  86        DM_STATUS_REPORT                = 5,
  87        DM_BALLOON_REQUEST              = 6,
  88        DM_BALLOON_RESPONSE             = 7,
  89        DM_UNBALLOON_REQUEST            = 8,
  90        DM_UNBALLOON_RESPONSE           = 9,
  91        DM_MEM_HOT_ADD_REQUEST          = 10,
  92        DM_MEM_HOT_ADD_RESPONSE         = 11,
  93        DM_VERSION_03_MAX               = 11,
  94        /*
  95         * Version 1.0.
  96         */
  97        DM_INFO_MESSAGE                 = 12,
  98        DM_VERSION_1_MAX                = 12
  99};
 100
 101
 102/*
 103 * Structures defining the dynamic memory management
 104 * protocol.
 105 */
 106
 107union dm_version {
 108        struct {
 109                __u16 minor_version;
 110                __u16 major_version;
 111        };
 112        __u32 version;
 113} __packed;
 114
 115
 116union dm_caps {
 117        struct {
 118                __u64 balloon:1;
 119                __u64 hot_add:1;
 120                /*
 121                 * To support guests that may have alignment
 122                 * limitations on hot-add, the guest can specify
 123                 * its alignment requirements; a value of n
 124                 * represents an alignment of 2^n in mega bytes.
 125                 */
 126                __u64 hot_add_alignment:4;
 127                __u64 reservedz:58;
 128        } cap_bits;
 129        __u64 caps;
 130} __packed;
 131
 132union dm_mem_page_range {
 133        struct  {
 134                /*
 135                 * The PFN number of the first page in the range.
 136                 * 40 bits is the architectural limit of a PFN
 137                 * number for AMD64.
 138                 */
 139                __u64 start_page:40;
 140                /*
 141                 * The number of pages in the range.
 142                 */
 143                __u64 page_cnt:24;
 144        } finfo;
 145        __u64  page_range;
 146} __packed;
 147
 148
 149
 150/*
 151 * The header for all dynamic memory messages:
 152 *
 153 * type: Type of the message.
 154 * size: Size of the message in bytes; including the header.
 155 * trans_id: The guest is responsible for manufacturing this ID.
 156 */
 157
 158struct dm_header {
 159        __u16 type;
 160        __u16 size;
 161        __u32 trans_id;
 162} __packed;
 163
 164/*
 165 * A generic message format for dynamic memory.
 166 * Specific message formats are defined later in the file.
 167 */
 168
 169struct dm_message {
 170        struct dm_header hdr;
 171        __u8 data[]; /* enclosed message */
 172} __packed;
 173
 174
 175/*
 176 * Specific message types supporting the dynamic memory protocol.
 177 */
 178
 179/*
 180 * Version negotiation message. Sent from the guest to the host.
 181 * The guest is free to try different versions until the host
 182 * accepts the version.
 183 *
 184 * dm_version: The protocol version requested.
 185 * is_last_attempt: If TRUE, this is the last version guest will request.
 186 * reservedz: Reserved field, set to zero.
 187 */
 188
 189struct dm_version_request {
 190        struct dm_header hdr;
 191        union dm_version version;
 192        __u32 is_last_attempt:1;
 193        __u32 reservedz:31;
 194} __packed;
 195
 196/*
 197 * Version response message; Host to Guest and indicates
 198 * if the host has accepted the version sent by the guest.
 199 *
 200 * is_accepted: If TRUE, host has accepted the version and the guest
 201 * should proceed to the next stage of the protocol. FALSE indicates that
 202 * guest should re-try with a different version.
 203 *
 204 * reservedz: Reserved field, set to zero.
 205 */
 206
 207struct dm_version_response {
 208        struct dm_header hdr;
 209        __u64 is_accepted:1;
 210        __u64 reservedz:63;
 211} __packed;
 212
 213/*
 214 * Message reporting capabilities. This is sent from the guest to the
 215 * host.
 216 */
 217
 218struct dm_capabilities {
 219        struct dm_header hdr;
 220        union dm_caps caps;
 221        __u64 min_page_cnt;
 222        __u64 max_page_number;
 223} __packed;
 224
 225/*
 226 * Response to the capabilities message. This is sent from the host to the
 227 * guest. This message notifies if the host has accepted the guest's
 228 * capabilities. If the host has not accepted, the guest must shutdown
 229 * the service.
 230 *
 231 * is_accepted: Indicates if the host has accepted guest's capabilities.
 232 * reservedz: Must be 0.
 233 */
 234
 235struct dm_capabilities_resp_msg {
 236        struct dm_header hdr;
 237        __u64 is_accepted:1;
 238        __u64 reservedz:63;
 239} __packed;
 240
 241/*
 242 * This message is used to report memory pressure from the guest.
 243 * This message is not part of any transaction and there is no
 244 * response to this message.
 245 *
 246 * num_avail: Available memory in pages.
 247 * num_committed: Committed memory in pages.
 248 * page_file_size: The accumulated size of all page files
 249 *                 in the system in pages.
 250 * zero_free: The nunber of zero and free pages.
 251 * page_file_writes: The writes to the page file in pages.
 252 * io_diff: An indicator of file cache efficiency or page file activity,
 253 *          calculated as File Cache Page Fault Count - Page Read Count.
 254 *          This value is in pages.
 255 *
 256 * Some of these metrics are Windows specific and fortunately
 257 * the algorithm on the host side that computes the guest memory
 258 * pressure only uses num_committed value.
 259 */
 260
 261struct dm_status {
 262        struct dm_header hdr;
 263        __u64 num_avail;
 264        __u64 num_committed;
 265        __u64 page_file_size;
 266        __u64 zero_free;
 267        __u32 page_file_writes;
 268        __u32 io_diff;
 269} __packed;
 270
 271
 272/*
 273 * Message to ask the guest to allocate memory - balloon up message.
 274 * This message is sent from the host to the guest. The guest may not be
 275 * able to allocate as much memory as requested.
 276 *
 277 * num_pages: number of pages to allocate.
 278 */
 279
 280struct dm_balloon {
 281        struct dm_header hdr;
 282        __u32 num_pages;
 283        __u32 reservedz;
 284} __packed;
 285
 286
 287/*
 288 * Balloon response message; this message is sent from the guest
 289 * to the host in response to the balloon message.
 290 *
 291 * reservedz: Reserved; must be set to zero.
 292 * more_pages: If FALSE, this is the last message of the transaction.
 293 * if TRUE there will atleast one more message from the guest.
 294 *
 295 * range_count: The number of ranges in the range array.
 296 *
 297 * range_array: An array of page ranges returned to the host.
 298 *
 299 */
 300
 301struct dm_balloon_response {
 302        struct dm_header hdr;
 303        __u32 reservedz;
 304        __u32 more_pages:1;
 305        __u32 range_count:31;
 306        union dm_mem_page_range range_array[];
 307} __packed;
 308
 309/*
 310 * Un-balloon message; this message is sent from the host
 311 * to the guest to give guest more memory.
 312 *
 313 * more_pages: If FALSE, this is the last message of the transaction.
 314 * if TRUE there will atleast one more message from the guest.
 315 *
 316 * reservedz: Reserved; must be set to zero.
 317 *
 318 * range_count: The number of ranges in the range array.
 319 *
 320 * range_array: An array of page ranges returned to the host.
 321 *
 322 */
 323
 324struct dm_unballoon_request {
 325        struct dm_header hdr;
 326        __u32 more_pages:1;
 327        __u32 reservedz:31;
 328        __u32 range_count;
 329        union dm_mem_page_range range_array[];
 330} __packed;
 331
 332/*
 333 * Un-balloon response message; this message is sent from the guest
 334 * to the host in response to an unballoon request.
 335 *
 336 */
 337
 338struct dm_unballoon_response {
 339        struct dm_header hdr;
 340} __packed;
 341
 342
 343/*
 344 * Hot add request message. Message sent from the host to the guest.
 345 *
 346 * mem_range: Memory range to hot add.
 347 *
 348 * On Linux we currently don't support this since we cannot hot add
 349 * arbitrary granularity of memory.
 350 */
 351
 352struct dm_hot_add {
 353        struct dm_header hdr;
 354        union dm_mem_page_range range;
 355} __packed;
 356
 357/*
 358 * Hot add response message.
 359 * This message is sent by the guest to report the status of a hot add request.
 360 * If page_count is less than the requested page count, then the host should
 361 * assume all further hot add requests will fail, since this indicates that
 362 * the guest has hit an upper physical memory barrier.
 363 *
 364 * Hot adds may also fail due to low resources; in this case, the guest must
 365 * not complete this message until the hot add can succeed, and the host must
 366 * not send a new hot add request until the response is sent.
 367 * If VSC fails to hot add memory DYNMEM_NUMBER_OF_UNSUCCESSFUL_HOTADD_ATTEMPTS
 368 * times it fails the request.
 369 *
 370 *
 371 * page_count: number of pages that were successfully hot added.
 372 *
 373 * result: result of the operation 1: success, 0: failure.
 374 *
 375 */
 376
 377struct dm_hot_add_response {
 378        struct dm_header hdr;
 379        __u32 page_count;
 380        __u32 result;
 381} __packed;
 382
 383/*
 384 * Types of information sent from host to the guest.
 385 */
 386
 387enum dm_info_type {
 388        INFO_TYPE_MAX_PAGE_CNT = 0,
 389        MAX_INFO_TYPE
 390};
 391
 392
 393/*
 394 * Header for the information message.
 395 */
 396
 397struct dm_info_header {
 398        enum dm_info_type type;
 399        __u32 data_size;
 400} __packed;
 401
 402/*
 403 * This message is sent from the host to the guest to pass
 404 * some relevant information (win8 addition).
 405 *
 406 * reserved: no used.
 407 * info_size: size of the information blob.
 408 * info: information blob.
 409 */
 410
 411struct dm_info_msg {
 412        struct dm_header hdr;
 413        __u32 reserved;
 414        __u32 info_size;
 415        __u8  info[];
 416};
 417
 418/*
 419 * End protocol definitions.
 420 */
 421
 422/*
 423 * State to manage hot adding memory into the guest.
 424 * The range start_pfn : end_pfn specifies the range
 425 * that the host has asked us to hot add. The range
 426 * start_pfn : ha_end_pfn specifies the range that we have
 427 * currently hot added. We hot add in multiples of 128M
 428 * chunks; it is possible that we may not be able to bring
 429 * online all the pages in the region. The range
 430 * covered_start_pfn : covered_end_pfn defines the pages that can
 431 * be brough online.
 432 */
 433
 434struct hv_hotadd_state {
 435        struct list_head list;
 436        unsigned long start_pfn;
 437        unsigned long covered_start_pfn;
 438        unsigned long covered_end_pfn;
 439        unsigned long ha_end_pfn;
 440        unsigned long end_pfn;
 441};
 442
 443struct balloon_state {
 444        __u32 num_pages;
 445        struct work_struct wrk;
 446};
 447
 448struct hot_add_wrk {
 449        union dm_mem_page_range ha_page_range;
 450        union dm_mem_page_range ha_region_range;
 451        struct work_struct wrk;
 452};
 453
 454static bool hot_add = true;
 455static bool do_hot_add;
 456/*
 457 * Delay reporting memory pressure by
 458 * the specified number of seconds.
 459 */
 460static uint pressure_report_delay = 45;
 461
 462module_param(hot_add, bool, (S_IRUGO | S_IWUSR));
 463MODULE_PARM_DESC(hot_add, "If set attempt memory hot_add");
 464
 465module_param(pressure_report_delay, uint, (S_IRUGO | S_IWUSR));
 466MODULE_PARM_DESC(pressure_report_delay, "Delay in secs in reporting pressure");
 467static atomic_t trans_id = ATOMIC_INIT(0);
 468
 469static int dm_ring_size = (5 * PAGE_SIZE);
 470
 471/*
 472 * Driver specific state.
 473 */
 474
 475enum hv_dm_state {
 476        DM_INITIALIZING = 0,
 477        DM_INITIALIZED,
 478        DM_BALLOON_UP,
 479        DM_BALLOON_DOWN,
 480        DM_HOT_ADD,
 481        DM_INIT_ERROR
 482};
 483
 484
 485static __u8 recv_buffer[PAGE_SIZE];
 486static __u8 *send_buffer;
 487#define PAGES_IN_2M     512
 488#define HA_CHUNK (32 * 1024)
 489
 490struct hv_dynmem_device {
 491        struct hv_device *dev;
 492        enum hv_dm_state state;
 493        struct completion host_event;
 494        struct completion config_event;
 495
 496        /*
 497         * Number of pages we have currently ballooned out.
 498         */
 499        unsigned int num_pages_ballooned;
 500
 501        /*
 502         * State to manage the ballooning (up) operation.
 503         */
 504        struct balloon_state balloon_wrk;
 505
 506        /*
 507         * State to execute the "hot-add" operation.
 508         */
 509        struct hot_add_wrk ha_wrk;
 510
 511        /*
 512         * This state tracks if the host has specified a hot-add
 513         * region.
 514         */
 515        bool host_specified_ha_region;
 516
 517        /*
 518         * State to synchronize hot-add.
 519         */
 520        struct completion  ol_waitevent;
 521        bool ha_waiting;
 522        /*
 523         * This thread handles hot-add
 524         * requests from the host as well as notifying
 525         * the host with regards to memory pressure in
 526         * the guest.
 527         */
 528        struct task_struct *thread;
 529
 530        /*
 531         * A list of hot-add regions.
 532         */
 533        struct list_head ha_region_list;
 534
 535        /*
 536         * We start with the highest version we can support
 537         * and downgrade based on the host; we save here the
 538         * next version to try.
 539         */
 540        __u32 next_version;
 541};
 542
 543static struct hv_dynmem_device dm_device;
 544
 545#ifdef CONFIG_MEMORY_HOTPLUG
 546
 547static void hv_bring_pgs_online(unsigned long start_pfn, unsigned long size)
 548{
 549        int i;
 550
 551        for (i = 0; i < size; i++) {
 552                struct page *pg;
 553                pg = pfn_to_page(start_pfn + i);
 554                __online_page_set_limits(pg);
 555                __online_page_increment_counters(pg);
 556                __online_page_free(pg);
 557        }
 558}
 559
 560static void hv_mem_hot_add(unsigned long start, unsigned long size,
 561                                unsigned long pfn_count,
 562                                struct hv_hotadd_state *has)
 563{
 564        int ret = 0;
 565        int i, nid, t;
 566        unsigned long start_pfn;
 567        unsigned long processed_pfn;
 568        unsigned long total_pfn = pfn_count;
 569
 570        for (i = 0; i < (size/HA_CHUNK); i++) {
 571                start_pfn = start + (i * HA_CHUNK);
 572                has->ha_end_pfn +=  HA_CHUNK;
 573
 574                if (total_pfn > HA_CHUNK) {
 575                        processed_pfn = HA_CHUNK;
 576                        total_pfn -= HA_CHUNK;
 577                } else {
 578                        processed_pfn = total_pfn;
 579                        total_pfn = 0;
 580                }
 581
 582                has->covered_end_pfn +=  processed_pfn;
 583
 584                init_completion(&dm_device.ol_waitevent);
 585                dm_device.ha_waiting = true;
 586
 587                nid = memory_add_physaddr_to_nid(PFN_PHYS(start_pfn));
 588                ret = add_memory(nid, PFN_PHYS((start_pfn)),
 589                                (HA_CHUNK << PAGE_SHIFT));
 590
 591                if (ret) {
 592                        pr_info("hot_add memory failed error is %d\n", ret);
 593                        if (ret == -EEXIST) {
 594                                /*
 595                                 * This error indicates that the error
 596                                 * is not a transient failure. This is the
 597                                 * case where the guest's physical address map
 598                                 * precludes hot adding memory. Stop all further
 599                                 * memory hot-add.
 600                                 */
 601                                do_hot_add = false;
 602                        }
 603                        has->ha_end_pfn -= HA_CHUNK;
 604                        has->covered_end_pfn -=  processed_pfn;
 605                        break;
 606                }
 607
 608                /*
 609                 * Wait for the memory block to be onlined.
 610                 */
 611                t = wait_for_completion_timeout(&dm_device.ol_waitevent, 5*HZ);
 612                if (t == 0) {
 613                        pr_info("hot_add memory timedout\n");
 614                        has->ha_end_pfn -= HA_CHUNK;
 615                        has->covered_end_pfn -=  processed_pfn;
 616                        break;
 617                }
 618
 619        }
 620
 621        return;
 622}
 623
 624static void hv_online_page(struct page *pg)
 625{
 626        struct list_head *cur;
 627        struct hv_hotadd_state *has;
 628        unsigned long cur_start_pgp;
 629        unsigned long cur_end_pgp;
 630
 631        if (dm_device.ha_waiting) {
 632                dm_device.ha_waiting = false;
 633                complete(&dm_device.ol_waitevent);
 634        }
 635
 636        list_for_each(cur, &dm_device.ha_region_list) {
 637                has = list_entry(cur, struct hv_hotadd_state, list);
 638                cur_start_pgp = (unsigned long)
 639                                pfn_to_page(has->covered_start_pfn);
 640                cur_end_pgp = (unsigned long)pfn_to_page(has->covered_end_pfn);
 641
 642                if (((unsigned long)pg >= cur_start_pgp) &&
 643                        ((unsigned long)pg < cur_end_pgp)) {
 644                        /*
 645                         * This frame is currently backed; online the
 646                         * page.
 647                         */
 648                        __online_page_set_limits(pg);
 649                        __online_page_increment_counters(pg);
 650                        __online_page_free(pg);
 651                        has->covered_start_pfn++;
 652                }
 653        }
 654}
 655
 656static bool pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt)
 657{
 658        struct list_head *cur;
 659        struct hv_hotadd_state *has;
 660        unsigned long residual, new_inc;
 661
 662        if (list_empty(&dm_device.ha_region_list))
 663                return false;
 664
 665        list_for_each(cur, &dm_device.ha_region_list) {
 666                has = list_entry(cur, struct hv_hotadd_state, list);
 667
 668                /*
 669                 * If the pfn range we are dealing with is not in the current
 670                 * "hot add block", move on.
 671                 */
 672                if ((start_pfn >= has->end_pfn))
 673                        continue;
 674                /*
 675                 * If the current hot add-request extends beyond
 676                 * our current limit; extend it.
 677                 */
 678                if ((start_pfn + pfn_cnt) > has->end_pfn) {
 679                        residual = (start_pfn + pfn_cnt - has->end_pfn);
 680                        /*
 681                         * Extend the region by multiples of HA_CHUNK.
 682                         */
 683                        new_inc = (residual / HA_CHUNK) * HA_CHUNK;
 684                        if (residual % HA_CHUNK)
 685                                new_inc += HA_CHUNK;
 686
 687                        has->end_pfn += new_inc;
 688                }
 689
 690                /*
 691                 * If the current start pfn is not where the covered_end
 692                 * is, update it.
 693                 */
 694
 695                if (has->covered_end_pfn != start_pfn) {
 696                        has->covered_end_pfn = start_pfn;
 697                        has->covered_start_pfn = start_pfn;
 698                }
 699                return true;
 700
 701        }
 702
 703        return false;
 704}
 705
 706static unsigned long handle_pg_range(unsigned long pg_start,
 707                                        unsigned long pg_count)
 708{
 709        unsigned long start_pfn = pg_start;
 710        unsigned long pfn_cnt = pg_count;
 711        unsigned long size;
 712        struct list_head *cur;
 713        struct hv_hotadd_state *has;
 714        unsigned long pgs_ol = 0;
 715        unsigned long old_covered_state;
 716
 717        if (list_empty(&dm_device.ha_region_list))
 718                return 0;
 719
 720        list_for_each(cur, &dm_device.ha_region_list) {
 721                has = list_entry(cur, struct hv_hotadd_state, list);
 722
 723                /*
 724                 * If the pfn range we are dealing with is not in the current
 725                 * "hot add block", move on.
 726                 */
 727                if ((start_pfn >= has->end_pfn))
 728                        continue;
 729
 730                old_covered_state = has->covered_end_pfn;
 731
 732                if (start_pfn < has->ha_end_pfn) {
 733                        /*
 734                         * This is the case where we are backing pages
 735                         * in an already hot added region. Bring
 736                         * these pages online first.
 737                         */
 738                        pgs_ol = has->ha_end_pfn - start_pfn;
 739                        if (pgs_ol > pfn_cnt)
 740                                pgs_ol = pfn_cnt;
 741                        hv_bring_pgs_online(start_pfn, pgs_ol);
 742                        has->covered_end_pfn +=  pgs_ol;
 743                        has->covered_start_pfn +=  pgs_ol;
 744                        pfn_cnt -= pgs_ol;
 745                }
 746
 747                if ((has->ha_end_pfn < has->end_pfn) && (pfn_cnt > 0)) {
 748                        /*
 749                         * We have some residual hot add range
 750                         * that needs to be hot added; hot add
 751                         * it now. Hot add a multiple of
 752                         * of HA_CHUNK that fully covers the pages
 753                         * we have.
 754                         */
 755                        size = (has->end_pfn - has->ha_end_pfn);
 756                        if (pfn_cnt <= size) {
 757                                size = ((pfn_cnt / HA_CHUNK) * HA_CHUNK);
 758                                if (pfn_cnt % HA_CHUNK)
 759                                        size += HA_CHUNK;
 760                        } else {
 761                                pfn_cnt = size;
 762                        }
 763                        hv_mem_hot_add(has->ha_end_pfn, size, pfn_cnt, has);
 764                }
 765                /*
 766                 * If we managed to online any pages that were given to us,
 767                 * we declare success.
 768                 */
 769                return has->covered_end_pfn - old_covered_state;
 770
 771        }
 772
 773        return 0;
 774}
 775
 776static unsigned long process_hot_add(unsigned long pg_start,
 777                                        unsigned long pfn_cnt,
 778                                        unsigned long rg_start,
 779                                        unsigned long rg_size)
 780{
 781        struct hv_hotadd_state *ha_region = NULL;
 782
 783        if (pfn_cnt == 0)
 784                return 0;
 785
 786        if (!dm_device.host_specified_ha_region)
 787                if (pfn_covered(pg_start, pfn_cnt))
 788                        goto do_pg_range;
 789
 790        /*
 791         * If the host has specified a hot-add range; deal with it first.
 792         */
 793
 794        if (rg_size != 0) {
 795                ha_region = kzalloc(sizeof(struct hv_hotadd_state), GFP_KERNEL);
 796                if (!ha_region)
 797                        return 0;
 798
 799                INIT_LIST_HEAD(&ha_region->list);
 800
 801                list_add_tail(&ha_region->list, &dm_device.ha_region_list);
 802                ha_region->start_pfn = rg_start;
 803                ha_region->ha_end_pfn = rg_start;
 804                ha_region->covered_start_pfn = pg_start;
 805                ha_region->covered_end_pfn = pg_start;
 806                ha_region->end_pfn = rg_start + rg_size;
 807        }
 808
 809do_pg_range:
 810        /*
 811         * Process the page range specified; bringing them
 812         * online if possible.
 813         */
 814        return handle_pg_range(pg_start, pfn_cnt);
 815}
 816
 817#endif
 818
 819static void hot_add_req(struct work_struct *dummy)
 820{
 821        struct dm_hot_add_response resp;
 822#ifdef CONFIG_MEMORY_HOTPLUG
 823        unsigned long pg_start, pfn_cnt;
 824        unsigned long rg_start, rg_sz;
 825#endif
 826        struct hv_dynmem_device *dm = &dm_device;
 827
 828        memset(&resp, 0, sizeof(struct dm_hot_add_response));
 829        resp.hdr.type = DM_MEM_HOT_ADD_RESPONSE;
 830        resp.hdr.size = sizeof(struct dm_hot_add_response);
 831        resp.hdr.trans_id = atomic_inc_return(&trans_id);
 832
 833#ifdef CONFIG_MEMORY_HOTPLUG
 834        pg_start = dm->ha_wrk.ha_page_range.finfo.start_page;
 835        pfn_cnt = dm->ha_wrk.ha_page_range.finfo.page_cnt;
 836
 837        rg_start = dm->ha_wrk.ha_region_range.finfo.start_page;
 838        rg_sz = dm->ha_wrk.ha_region_range.finfo.page_cnt;
 839
 840        if ((rg_start == 0) && (!dm->host_specified_ha_region)) {
 841                unsigned long region_size;
 842                unsigned long region_start;
 843
 844                /*
 845                 * The host has not specified the hot-add region.
 846                 * Based on the hot-add page range being specified,
 847                 * compute a hot-add region that can cover the pages
 848                 * that need to be hot-added while ensuring the alignment
 849                 * and size requirements of Linux as it relates to hot-add.
 850                 */
 851                region_start = pg_start;
 852                region_size = (pfn_cnt / HA_CHUNK) * HA_CHUNK;
 853                if (pfn_cnt % HA_CHUNK)
 854                        region_size += HA_CHUNK;
 855
 856                region_start = (pg_start / HA_CHUNK) * HA_CHUNK;
 857
 858                rg_start = region_start;
 859                rg_sz = region_size;
 860        }
 861
 862        if (do_hot_add)
 863                resp.page_count = process_hot_add(pg_start, pfn_cnt,
 864                                                rg_start, rg_sz);
 865#endif
 866        /*
 867         * The result field of the response structure has the
 868         * following semantics:
 869         *
 870         * 1. If all or some pages hot-added: Guest should return success.
 871         *
 872         * 2. If no pages could be hot-added:
 873         *
 874         * If the guest returns success, then the host
 875         * will not attempt any further hot-add operations. This
 876         * signifies a permanent failure.
 877         *
 878         * If the guest returns failure, then this failure will be
 879         * treated as a transient failure and the host may retry the
 880         * hot-add operation after some delay.
 881         */
 882        if (resp.page_count > 0)
 883                resp.result = 1;
 884        else if (!do_hot_add)
 885                resp.result = 1;
 886        else
 887                resp.result = 0;
 888
 889        if (!do_hot_add || (resp.page_count == 0))
 890                pr_info("Memory hot add failed\n");
 891
 892        dm->state = DM_INITIALIZED;
 893        vmbus_sendpacket(dm->dev->channel, &resp,
 894                        sizeof(struct dm_hot_add_response),
 895                        (unsigned long)NULL,
 896                        VM_PKT_DATA_INBAND, 0);
 897}
 898
 899static void process_info(struct hv_dynmem_device *dm, struct dm_info_msg *msg)
 900{
 901        struct dm_info_header *info_hdr;
 902
 903        info_hdr = (struct dm_info_header *)msg->info;
 904
 905        switch (info_hdr->type) {
 906        case INFO_TYPE_MAX_PAGE_CNT:
 907                pr_info("Received INFO_TYPE_MAX_PAGE_CNT\n");
 908                pr_info("Data Size is %d\n", info_hdr->data_size);
 909                break;
 910        default:
 911                pr_info("Received Unknown type: %d\n", info_hdr->type);
 912        }
 913}
 914
 915static unsigned long compute_balloon_floor(void)
 916{
 917        unsigned long min_pages;
 918#define MB2PAGES(mb) ((mb) << (20 - PAGE_SHIFT))
 919        /* Simple continuous piecewiese linear function:
 920         *  max MiB -> min MiB  gradient
 921         *       0         0
 922         *      16        16
 923         *      32        24
 924         *     128        72    (1/2)
 925         *     512       168    (1/4)
 926         *    2048       360    (1/8)
 927         *    8192       552    (1/32)
 928         *   32768      1320
 929         *  131072      4392
 930         */
 931        if (totalram_pages < MB2PAGES(128))
 932                min_pages = MB2PAGES(8) + (totalram_pages >> 1);
 933        else if (totalram_pages < MB2PAGES(512))
 934                min_pages = MB2PAGES(40) + (totalram_pages >> 2);
 935        else if (totalram_pages < MB2PAGES(2048))
 936                min_pages = MB2PAGES(104) + (totalram_pages >> 3);
 937        else
 938                min_pages = MB2PAGES(296) + (totalram_pages >> 5);
 939#undef MB2PAGES
 940        return min_pages;
 941}
 942
 943/*
 944 * Post our status as it relates memory pressure to the
 945 * host. Host expects the guests to post this status
 946 * periodically at 1 second intervals.
 947 *
 948 * The metrics specified in this protocol are very Windows
 949 * specific and so we cook up numbers here to convey our memory
 950 * pressure.
 951 */
 952
 953static void post_status(struct hv_dynmem_device *dm)
 954{
 955        struct dm_status status;
 956        struct sysinfo val;
 957
 958        if (pressure_report_delay > 0) {
 959                --pressure_report_delay;
 960                return;
 961        }
 962        si_meminfo(&val);
 963        memset(&status, 0, sizeof(struct dm_status));
 964        status.hdr.type = DM_STATUS_REPORT;
 965        status.hdr.size = sizeof(struct dm_status);
 966        status.hdr.trans_id = atomic_inc_return(&trans_id);
 967
 968        /*
 969         * The host expects the guest to report free memory.
 970         * Further, the host expects the pressure information to
 971         * include the ballooned out pages.
 972         * For a given amount of memory that we are managing, we
 973         * need to compute a floor below which we should not balloon.
 974         * Compute this and add it to the pressure report.
 975         */
 976        status.num_avail = val.freeram;
 977        status.num_committed = vm_memory_committed() +
 978                                dm->num_pages_ballooned +
 979                                compute_balloon_floor();
 980
 981        vmbus_sendpacket(dm->dev->channel, &status,
 982                                sizeof(struct dm_status),
 983                                (unsigned long)NULL,
 984                                VM_PKT_DATA_INBAND, 0);
 985
 986}
 987
 988static void free_balloon_pages(struct hv_dynmem_device *dm,
 989                         union dm_mem_page_range *range_array)
 990{
 991        int num_pages = range_array->finfo.page_cnt;
 992        __u64 start_frame = range_array->finfo.start_page;
 993        struct page *pg;
 994        int i;
 995
 996        for (i = 0; i < num_pages; i++) {
 997                pg = pfn_to_page(i + start_frame);
 998                __free_page(pg);
 999                dm->num_pages_ballooned--;
1000        }
1001}
1002
1003
1004
1005static int  alloc_balloon_pages(struct hv_dynmem_device *dm, int num_pages,
1006                         struct dm_balloon_response *bl_resp, int alloc_unit,
1007                         bool *alloc_error)
1008{
1009        int i = 0;
1010        struct page *pg;
1011
1012        if (num_pages < alloc_unit)
1013                return 0;
1014
1015        for (i = 0; (i * alloc_unit) < num_pages; i++) {
1016                if (bl_resp->hdr.size + sizeof(union dm_mem_page_range) >
1017                        PAGE_SIZE)
1018                        return i * alloc_unit;
1019
1020                /*
1021                 * We execute this code in a thread context. Furthermore,
1022                 * we don't want the kernel to try too hard.
1023                 */
1024                pg = alloc_pages(GFP_HIGHUSER | __GFP_NORETRY |
1025                                __GFP_NOMEMALLOC | __GFP_NOWARN,
1026                                get_order(alloc_unit << PAGE_SHIFT));
1027
1028                if (!pg) {
1029                        *alloc_error = true;
1030                        return i * alloc_unit;
1031                }
1032
1033
1034                dm->num_pages_ballooned += alloc_unit;
1035
1036                /*
1037                 * If we allocatted 2M pages; split them so we
1038                 * can free them in any order we get.
1039                 */
1040
1041                if (alloc_unit != 1)
1042                        split_page(pg, get_order(alloc_unit << PAGE_SHIFT));
1043
1044                bl_resp->range_count++;
1045                bl_resp->range_array[i].finfo.start_page =
1046                        page_to_pfn(pg);
1047                bl_resp->range_array[i].finfo.page_cnt = alloc_unit;
1048                bl_resp->hdr.size += sizeof(union dm_mem_page_range);
1049
1050        }
1051
1052        return num_pages;
1053}
1054
1055
1056
1057static void balloon_up(struct work_struct *dummy)
1058{
1059        int num_pages = dm_device.balloon_wrk.num_pages;
1060        int num_ballooned = 0;
1061        struct dm_balloon_response *bl_resp;
1062        int alloc_unit;
1063        int ret;
1064        bool alloc_error = false;
1065        bool done = false;
1066        int i;
1067
1068
1069        /*
1070         * We will attempt 2M allocations. However, if we fail to
1071         * allocate 2M chunks, we will go back to 4k allocations.
1072         */
1073        alloc_unit = 512;
1074
1075        while (!done) {
1076                bl_resp = (struct dm_balloon_response *)send_buffer;
1077                memset(send_buffer, 0, PAGE_SIZE);
1078                bl_resp->hdr.type = DM_BALLOON_RESPONSE;
1079                bl_resp->hdr.trans_id = atomic_inc_return(&trans_id);
1080                bl_resp->hdr.size = sizeof(struct dm_balloon_response);
1081                bl_resp->more_pages = 1;
1082
1083
1084                num_pages -= num_ballooned;
1085                num_ballooned = alloc_balloon_pages(&dm_device, num_pages,
1086                                                bl_resp, alloc_unit,
1087                                                 &alloc_error);
1088
1089                if ((alloc_error) && (alloc_unit != 1)) {
1090                        alloc_unit = 1;
1091                        continue;
1092                }
1093
1094                if ((alloc_error) || (num_ballooned == num_pages)) {
1095                        bl_resp->more_pages = 0;
1096                        done = true;
1097                        dm_device.state = DM_INITIALIZED;
1098                }
1099
1100                /*
1101                 * We are pushing a lot of data through the channel;
1102                 * deal with transient failures caused because of the
1103                 * lack of space in the ring buffer.
1104                 */
1105
1106                do {
1107                        ret = vmbus_sendpacket(dm_device.dev->channel,
1108                                                bl_resp,
1109                                                bl_resp->hdr.size,
1110                                                (unsigned long)NULL,
1111                                                VM_PKT_DATA_INBAND, 0);
1112
1113                        if (ret == -EAGAIN)
1114                                msleep(20);
1115
1116                } while (ret == -EAGAIN);
1117
1118                if (ret) {
1119                        /*
1120                         * Free up the memory we allocatted.
1121                         */
1122                        pr_info("Balloon response failed\n");
1123
1124                        for (i = 0; i < bl_resp->range_count; i++)
1125                                free_balloon_pages(&dm_device,
1126                                                 &bl_resp->range_array[i]);
1127
1128                        done = true;
1129                }
1130        }
1131
1132}
1133
1134static void balloon_down(struct hv_dynmem_device *dm,
1135                        struct dm_unballoon_request *req)
1136{
1137        union dm_mem_page_range *range_array = req->range_array;
1138        int range_count = req->range_count;
1139        struct dm_unballoon_response resp;
1140        int i;
1141
1142        for (i = 0; i < range_count; i++)
1143                free_balloon_pages(dm, &range_array[i]);
1144
1145        if (req->more_pages == 1)
1146                return;
1147
1148        memset(&resp, 0, sizeof(struct dm_unballoon_response));
1149        resp.hdr.type = DM_UNBALLOON_RESPONSE;
1150        resp.hdr.trans_id = atomic_inc_return(&trans_id);
1151        resp.hdr.size = sizeof(struct dm_unballoon_response);
1152
1153        vmbus_sendpacket(dm_device.dev->channel, &resp,
1154                                sizeof(struct dm_unballoon_response),
1155                                (unsigned long)NULL,
1156                                VM_PKT_DATA_INBAND, 0);
1157
1158        dm->state = DM_INITIALIZED;
1159}
1160
1161static void balloon_onchannelcallback(void *context);
1162
1163static int dm_thread_func(void *dm_dev)
1164{
1165        struct hv_dynmem_device *dm = dm_dev;
1166        int t;
1167
1168        while (!kthread_should_stop()) {
1169                t = wait_for_completion_timeout(&dm_device.config_event, 1*HZ);
1170                /*
1171                 * The host expects us to post information on the memory
1172                 * pressure every second.
1173                 */
1174
1175                if (t == 0)
1176                        post_status(dm);
1177
1178        }
1179
1180        return 0;
1181}
1182
1183
1184static void version_resp(struct hv_dynmem_device *dm,
1185                        struct dm_version_response *vresp)
1186{
1187        struct dm_version_request version_req;
1188        int ret;
1189
1190        if (vresp->is_accepted) {
1191                /*
1192                 * We are done; wakeup the
1193                 * context waiting for version
1194                 * negotiation.
1195                 */
1196                complete(&dm->host_event);
1197                return;
1198        }
1199        /*
1200         * If there are more versions to try, continue
1201         * with negotiations; if not
1202         * shutdown the service since we are not able
1203         * to negotiate a suitable version number
1204         * with the host.
1205         */
1206        if (dm->next_version == 0)
1207                goto version_error;
1208
1209        dm->next_version = 0;
1210        memset(&version_req, 0, sizeof(struct dm_version_request));
1211        version_req.hdr.type = DM_VERSION_REQUEST;
1212        version_req.hdr.size = sizeof(struct dm_version_request);
1213        version_req.hdr.trans_id = atomic_inc_return(&trans_id);
1214        version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN7;
1215        version_req.is_last_attempt = 1;
1216
1217        ret = vmbus_sendpacket(dm->dev->channel, &version_req,
1218                                sizeof(struct dm_version_request),
1219                                (unsigned long)NULL,
1220                                VM_PKT_DATA_INBAND, 0);
1221
1222        if (ret)
1223                goto version_error;
1224
1225        return;
1226
1227version_error:
1228        dm->state = DM_INIT_ERROR;
1229        complete(&dm->host_event);
1230}
1231
1232static void cap_resp(struct hv_dynmem_device *dm,
1233                        struct dm_capabilities_resp_msg *cap_resp)
1234{
1235        if (!cap_resp->is_accepted) {
1236                pr_info("Capabilities not accepted by host\n");
1237                dm->state = DM_INIT_ERROR;
1238        }
1239        complete(&dm->host_event);
1240}
1241
1242static void balloon_onchannelcallback(void *context)
1243{
1244        struct hv_device *dev = context;
1245        u32 recvlen;
1246        u64 requestid;
1247        struct dm_message *dm_msg;
1248        struct dm_header *dm_hdr;
1249        struct hv_dynmem_device *dm = hv_get_drvdata(dev);
1250        struct dm_balloon *bal_msg;
1251        struct dm_hot_add *ha_msg;
1252        union dm_mem_page_range *ha_pg_range;
1253        union dm_mem_page_range *ha_region;
1254
1255        memset(recv_buffer, 0, sizeof(recv_buffer));
1256        vmbus_recvpacket(dev->channel, recv_buffer,
1257                         PAGE_SIZE, &recvlen, &requestid);
1258
1259        if (recvlen > 0) {
1260                dm_msg = (struct dm_message *)recv_buffer;
1261                dm_hdr = &dm_msg->hdr;
1262
1263                switch (dm_hdr->type) {
1264                case DM_VERSION_RESPONSE:
1265                        version_resp(dm,
1266                                 (struct dm_version_response *)dm_msg);
1267                        break;
1268
1269                case DM_CAPABILITIES_RESPONSE:
1270                        cap_resp(dm,
1271                                 (struct dm_capabilities_resp_msg *)dm_msg);
1272                        break;
1273
1274                case DM_BALLOON_REQUEST:
1275                        if (dm->state == DM_BALLOON_UP)
1276                                pr_warn("Currently ballooning\n");
1277                        bal_msg = (struct dm_balloon *)recv_buffer;
1278                        dm->state = DM_BALLOON_UP;
1279                        dm_device.balloon_wrk.num_pages = bal_msg->num_pages;
1280                        schedule_work(&dm_device.balloon_wrk.wrk);
1281                        break;
1282
1283                case DM_UNBALLOON_REQUEST:
1284                        dm->state = DM_BALLOON_DOWN;
1285                        balloon_down(dm,
1286                                 (struct dm_unballoon_request *)recv_buffer);
1287                        break;
1288
1289                case DM_MEM_HOT_ADD_REQUEST:
1290                        if (dm->state == DM_HOT_ADD)
1291                                pr_warn("Currently hot-adding\n");
1292                        dm->state = DM_HOT_ADD;
1293                        ha_msg = (struct dm_hot_add *)recv_buffer;
1294                        if (ha_msg->hdr.size == sizeof(struct dm_hot_add)) {
1295                                /*
1296                                 * This is a normal hot-add request specifying
1297                                 * hot-add memory.
1298                                 */
1299                                ha_pg_range = &ha_msg->range;
1300                                dm->ha_wrk.ha_page_range = *ha_pg_range;
1301                                dm->ha_wrk.ha_region_range.page_range = 0;
1302                        } else {
1303                                /*
1304                                 * Host is specifying that we first hot-add
1305                                 * a region and then partially populate this
1306                                 * region.
1307                                 */
1308                                dm->host_specified_ha_region = true;
1309                                ha_pg_range = &ha_msg->range;
1310                                ha_region = &ha_pg_range[1];
1311                                dm->ha_wrk.ha_page_range = *ha_pg_range;
1312                                dm->ha_wrk.ha_region_range = *ha_region;
1313                        }
1314                        schedule_work(&dm_device.ha_wrk.wrk);
1315                        break;
1316
1317                case DM_INFO_MESSAGE:
1318                        process_info(dm, (struct dm_info_msg *)dm_msg);
1319                        break;
1320
1321                default:
1322                        pr_err("Unhandled message: type: %d\n", dm_hdr->type);
1323
1324                }
1325        }
1326
1327}
1328
1329static int balloon_probe(struct hv_device *dev,
1330                        const struct hv_vmbus_device_id *dev_id)
1331{
1332        int ret, t;
1333        struct dm_version_request version_req;
1334        struct dm_capabilities cap_msg;
1335
1336        do_hot_add = hot_add;
1337
1338        /*
1339         * First allocate a send buffer.
1340         */
1341
1342        send_buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
1343        if (!send_buffer)
1344                return -ENOMEM;
1345
1346        ret = vmbus_open(dev->channel, dm_ring_size, dm_ring_size, NULL, 0,
1347                        balloon_onchannelcallback, dev);
1348
1349        if (ret)
1350                goto probe_error0;
1351
1352        dm_device.dev = dev;
1353        dm_device.state = DM_INITIALIZING;
1354        dm_device.next_version = DYNMEM_PROTOCOL_VERSION_WIN7;
1355        init_completion(&dm_device.host_event);
1356        init_completion(&dm_device.config_event);
1357        INIT_LIST_HEAD(&dm_device.ha_region_list);
1358        INIT_WORK(&dm_device.balloon_wrk.wrk, balloon_up);
1359        INIT_WORK(&dm_device.ha_wrk.wrk, hot_add_req);
1360        dm_device.host_specified_ha_region = false;
1361
1362        dm_device.thread =
1363                 kthread_run(dm_thread_func, &dm_device, "hv_balloon");
1364        if (IS_ERR(dm_device.thread)) {
1365                ret = PTR_ERR(dm_device.thread);
1366                goto probe_error1;
1367        }
1368
1369#ifdef CONFIG_MEMORY_HOTPLUG
1370        set_online_page_callback(&hv_online_page);
1371#endif
1372
1373        hv_set_drvdata(dev, &dm_device);
1374        /*
1375         * Initiate the hand shake with the host and negotiate
1376         * a version that the host can support. We start with the
1377         * highest version number and go down if the host cannot
1378         * support it.
1379         */
1380        memset(&version_req, 0, sizeof(struct dm_version_request));
1381        version_req.hdr.type = DM_VERSION_REQUEST;
1382        version_req.hdr.size = sizeof(struct dm_version_request);
1383        version_req.hdr.trans_id = atomic_inc_return(&trans_id);
1384        version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN8;
1385        version_req.is_last_attempt = 0;
1386
1387        ret = vmbus_sendpacket(dev->channel, &version_req,
1388                                sizeof(struct dm_version_request),
1389                                (unsigned long)NULL,
1390                                VM_PKT_DATA_INBAND, 0);
1391        if (ret)
1392                goto probe_error2;
1393
1394        t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ);
1395        if (t == 0) {
1396                ret = -ETIMEDOUT;
1397                goto probe_error2;
1398        }
1399
1400        /*
1401         * If we could not negotiate a compatible version with the host
1402         * fail the probe function.
1403         */
1404        if (dm_device.state == DM_INIT_ERROR) {
1405                ret = -ETIMEDOUT;
1406                goto probe_error2;
1407        }
1408        /*
1409         * Now submit our capabilities to the host.
1410         */
1411        memset(&cap_msg, 0, sizeof(struct dm_capabilities));
1412        cap_msg.hdr.type = DM_CAPABILITIES_REPORT;
1413        cap_msg.hdr.size = sizeof(struct dm_capabilities);
1414        cap_msg.hdr.trans_id = atomic_inc_return(&trans_id);
1415
1416        cap_msg.caps.cap_bits.balloon = 1;
1417        cap_msg.caps.cap_bits.hot_add = 1;
1418
1419        /*
1420         * Specify our alignment requirements as it relates
1421         * memory hot-add. Specify 128MB alignment.
1422         */
1423        cap_msg.caps.cap_bits.hot_add_alignment = 7;
1424
1425        /*
1426         * Currently the host does not use these
1427         * values and we set them to what is done in the
1428         * Windows driver.
1429         */
1430        cap_msg.min_page_cnt = 0;
1431        cap_msg.max_page_number = -1;
1432
1433        ret = vmbus_sendpacket(dev->channel, &cap_msg,
1434                                sizeof(struct dm_capabilities),
1435                                (unsigned long)NULL,
1436                                VM_PKT_DATA_INBAND, 0);
1437        if (ret)
1438                goto probe_error2;
1439
1440        t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ);
1441        if (t == 0) {
1442                ret = -ETIMEDOUT;
1443                goto probe_error2;
1444        }
1445
1446        /*
1447         * If the host does not like our capabilities,
1448         * fail the probe function.
1449         */
1450        if (dm_device.state == DM_INIT_ERROR) {
1451                ret = -ETIMEDOUT;
1452                goto probe_error2;
1453        }
1454
1455        dm_device.state = DM_INITIALIZED;
1456
1457        return 0;
1458
1459probe_error2:
1460#ifdef CONFIG_MEMORY_HOTPLUG
1461        restore_online_page_callback(&hv_online_page);
1462#endif
1463        kthread_stop(dm_device.thread);
1464
1465probe_error1:
1466        vmbus_close(dev->channel);
1467probe_error0:
1468        kfree(send_buffer);
1469        return ret;
1470}
1471
1472static int balloon_remove(struct hv_device *dev)
1473{
1474        struct hv_dynmem_device *dm = hv_get_drvdata(dev);
1475        struct list_head *cur, *tmp;
1476        struct hv_hotadd_state *has;
1477
1478        if (dm->num_pages_ballooned != 0)
1479                pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned);
1480
1481        cancel_work_sync(&dm->balloon_wrk.wrk);
1482        cancel_work_sync(&dm->ha_wrk.wrk);
1483
1484        vmbus_close(dev->channel);
1485        kthread_stop(dm->thread);
1486        kfree(send_buffer);
1487#ifdef CONFIG_MEMORY_HOTPLUG
1488        restore_online_page_callback(&hv_online_page);
1489#endif
1490        list_for_each_safe(cur, tmp, &dm->ha_region_list) {
1491                has = list_entry(cur, struct hv_hotadd_state, list);
1492                list_del(&has->list);
1493                kfree(has);
1494        }
1495
1496        return 0;
1497}
1498
1499static const struct hv_vmbus_device_id id_table[] = {
1500        /* Dynamic Memory Class ID */
1501        /* 525074DC-8985-46e2-8057-A307DC18A502 */
1502        { HV_DM_GUID, },
1503        { },
1504};
1505
1506MODULE_DEVICE_TABLE(vmbus, id_table);
1507
1508static  struct hv_driver balloon_drv = {
1509        .name = "hv_balloon",
1510        .id_table = id_table,
1511        .probe =  balloon_probe,
1512        .remove =  balloon_remove,
1513};
1514
1515static int __init init_balloon_drv(void)
1516{
1517
1518        return vmbus_driver_register(&balloon_drv);
1519}
1520
1521module_init(init_balloon_drv);
1522
1523MODULE_DESCRIPTION("Hyper-V Balloon");
1524MODULE_VERSION(HV_DRV_VERSION);
1525MODULE_LICENSE("GPL");
1526
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.