drivers/hv/hv_balloon.c

   1 /*
   2  * Copyright (c) 2012, Microsoft Corporation.
   3  *
   4  * Author:
   5  *   K. Y. Srinivasan <kys@microsoft.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License version 2 as published
   9  * by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  14  * NON INFRINGEMENT.  See the GNU General Public License for more
  15  * details.
  16  *
  17  */
  18
  19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  20
  21 #include <linux/kernel.h>
  22 #include <linux/jiffies.h>
  23 #include <linux/mman.h>
  24 #include <linux/delay.h>
  25 #include <linux/init.h>
  26 #include <linux/module.h>
  27 #include <linux/slab.h>
  28 #include <linux/kthread.h>
  29 #include <linux/completion.h>
  30 #include <linux/memory_hotplug.h>
  31 #include <linux/memory.h>
  32 #include <linux/notifier.h>
  33 #include <linux/percpu_counter.h>
  34
  35 #include <linux/hyperv.h>
  36
  37 /*
  38  * We begin with definitions supporting the Dynamic Memory protocol
  39  * with the host.
  40  *
  41  * Begin protocol definitions.
  42  */
  43
  44
  45
  46 /*
  47  * Protocol versions. The low word is the minor version, the high word the major
  48  * version.
  49  *
  50  * History:
  51  * Initial version 1.0
  52  * Changed to 0.1 on 2009/03/25
  53  * Changes to 0.2 on 2009/05/14
  54  * Changes to 0.3 on 2009/12/03
  55  * Changed to 1.0 on 2011/04/05
  56  */
  57
  58 #define DYNMEM_MAKE_VERSION(Major, Minor) ((__u32)(((Major) << 16) | (Minor)))
  59 #define DYNMEM_MAJOR_VERSION(Version) ((__u32)(Version) >> 16)
  60 #define DYNMEM_MINOR_VERSION(Version) ((__u32)(Version) & 0xff)
  61
  62 enum {
  63         DYNMEM_PROTOCOL_VERSION_1 = DYNMEM_MAKE_VERSION(0, 3),
  64         DYNMEM_PROTOCOL_VERSION_2 = DYNMEM_MAKE_VERSION(1, 0),
  65         DYNMEM_PROTOCOL_VERSION_3 = DYNMEM_MAKE_VERSION(2, 0),
  66
  67         DYNMEM_PROTOCOL_VERSION_WIN7 = DYNMEM_PROTOCOL_VERSION_1,
  68         DYNMEM_PROTOCOL_VERSION_WIN8 = DYNMEM_PROTOCOL_VERSION_2,
  69         DYNMEM_PROTOCOL_VERSION_WIN10 = DYNMEM_PROTOCOL_VERSION_3,
  70
  71         DYNMEM_PROTOCOL_VERSION_CURRENT = DYNMEM_PROTOCOL_VERSION_WIN10
  72 };
  73
  74
  75
  76 /*
  77  * Message Types
  78  */
  79
  80 enum dm_message_type {
  81         /*
  82          * Version 0.3
  83          */
  84         DM_ERROR                        = 0,
  85         DM_VERSION_REQUEST              = 1,
  86         DM_VERSION_RESPONSE             = 2,
  87         DM_CAPABILITIES_REPORT          = 3,
  88         DM_CAPABILITIES_RESPONSE        = 4,
  89         DM_STATUS_REPORT                = 5,
  90         DM_BALLOON_REQUEST              = 6,
  91         DM_BALLOON_RESPONSE             = 7,
  92         DM_UNBALLOON_REQUEST            = 8,
  93         DM_UNBALLOON_RESPONSE           = 9,
  94         DM_MEM_HOT_ADD_REQUEST          = 10,
  95         DM_MEM_HOT_ADD_RESPONSE         = 11,
  96         DM_VERSION_03_MAX               = 11,
  97         /*
  98          * Version 1.0.
  99          */
 100         DM_INFO_MESSAGE                 = 12,
 101         DM_VERSION_1_MAX                = 12
 102 };
 103
 104
 105 /*
 106  * Structures defining the dynamic memory management
 107  * protocol.
 108  */
 109
 110 union dm_version {
 111         struct {
 112                 __u16 minor_version;
 113                 __u16 major_version;
 114         };
 115         __u32 version;
 116 } __packed;
 117
 118
 119 union dm_caps {
 120         struct {
 121                 __u64 balloon:1;
 122                 __u64 hot_add:1;
 123                 /*
 124                  * To support guests that may have alignment
 125                  * limitations on hot-add, the guest can specify
 126                  * its alignment requirements; a value of n
 127                  * represents an alignment of 2^n in mega bytes.
 128                  */
 129                 __u64 hot_add_alignment:4;
 130                 __u64 reservedz:58;
 131         } cap_bits;
 132         __u64 caps;
 133 } __packed;
 134
 135 union dm_mem_page_range {
 136         struct  {
 137                 /*
 138                  * The PFN number of the first page in the range.
 139                  * 40 bits is the architectural limit of a PFN
 140                  * number for AMD64.
 141                  */
 142                 __u64 start_page:40;
 143                 /*
 144                  * The number of pages in the range.
 145                  */
 146                 __u64 page_cnt:24;
 147         } finfo;
 148         __u64  page_range;
 149 } __packed;
 150
 151
 152
 153 /*
 154  * The header for all dynamic memory messages:
 155  *
 156  * type: Type of the message.
 157  * size: Size of the message in bytes; including the header.
 158  * trans_id: The guest is responsible for manufacturing this ID.
 159  */
 160
 161 struct dm_header {
 162         __u16 type;
 163         __u16 size;
 164         __u32 trans_id;
 165 } __packed;
 166
 167 /*
 168  * A generic message format for dynamic memory.
 169  * Specific message formats are defined later in the file.
 170  */
 171
 172 struct dm_message {
 173         struct dm_header hdr;
 174         __u8 data[]; /* enclosed message */
 175 } __packed;
 176
 177
 178 /*
 179  * Specific message types supporting the dynamic memory protocol.
 180  */
 181
 182 /*
 183  * Version negotiation message. Sent from the guest to the host.
 184  * The guest is free to try different versions until the host
 185  * accepts the version.
 186  *
 187  * dm_version: The protocol version requested.
 188  * is_last_attempt: If TRUE, this is the last version guest will request.
 189  * reservedz: Reserved field, set to zero.
 190  */
 191
 192 struct dm_version_request {
 193         struct dm_header hdr;
 194         union dm_version version;
 195         __u32 is_last_attempt:1;
 196         __u32 reservedz:31;
 197 } __packed;
 198
 199 /*
 200  * Version response message; Host to Guest and indicates
 201  * if the host has accepted the version sent by the guest.
 202  *
 203  * is_accepted: If TRUE, host has accepted the version and the guest
 204  * should proceed to the next stage of the protocol. FALSE indicates that
 205  * guest should re-try with a different version.
 206  *
 207  * reservedz: Reserved field, set to zero.
 208  */
 209
 210 struct dm_version_response {
 211         struct dm_header hdr;
 212         __u64 is_accepted:1;
 213         __u64 reservedz:63;
 214 } __packed;
 215
 216 /*
 217  * Message reporting capabilities. This is sent from the guest to the
 218  * host.
 219  */
 220
 221 struct dm_capabilities {
 222         struct dm_header hdr;
 223         union dm_caps caps;
 224         __u64 min_page_cnt;
 225         __u64 max_page_number;
 226 } __packed;
 227
 228 /*
 229  * Response to the capabilities message. This is sent from the host to the
 230  * guest. This message notifies if the host has accepted the guest's
 231  * capabilities. If the host has not accepted, the guest must shutdown
 232  * the service.
 233  *
 234  * is_accepted: Indicates if the host has accepted guest's capabilities.
 235  * reservedz: Must be 0.
 236  */
 237
 238 struct dm_capabilities_resp_msg {
 239         struct dm_header hdr;
 240         __u64 is_accepted:1;
 241         __u64 reservedz:63;
 242 } __packed;
 243
 244 /*
 245  * This message is used to report memory pressure from the guest.
 246  * This message is not part of any transaction and there is no
 247  * response to this message.
 248  *
 249  * num_avail: Available memory in pages.
 250  * num_committed: Committed memory in pages.
 251  * page_file_size: The accumulated size of all page files
 252  *                 in the system in pages.
 253  * zero_free: The nunber of zero and free pages.
 254  * page_file_writes: The writes to the page file in pages.
 255  * io_diff: An indicator of file cache efficiency or page file activity,
 256  *          calculated as File Cache Page Fault Count - Page Read Count.
 257  *          This value is in pages.
 258  *
 259  * Some of these metrics are Windows specific and fortunately
 260  * the algorithm on the host side that computes the guest memory
 261  * pressure only uses num_committed value.
 262  */
 263
 264 struct dm_status {
 265         struct dm_header hdr;
 266         __u64 num_avail;
 267         __u64 num_committed;
 268         __u64 page_file_size;
 269         __u64 zero_free;
 270         __u32 page_file_writes;
 271         __u32 io_diff;
 272 } __packed;
 273
 274
 275 /*
 276  * Message to ask the guest to allocate memory - balloon up message.
 277  * This message is sent from the host to the guest. The guest may not be
 278  * able to allocate as much memory as requested.
 279  *
 280  * num_pages: number of pages to allocate.
 281  */
 282
 283 struct dm_balloon {
 284         struct dm_header hdr;
 285         __u32 num_pages;
 286         __u32 reservedz;
 287 } __packed;
 288
 289
 290 /*
 291  * Balloon response message; this message is sent from the guest
 292  * to the host in response to the balloon message.
 293  *
 294  * reservedz: Reserved; must be set to zero.
 295  * more_pages: If FALSE, this is the last message of the transaction.
 296  * if TRUE there will atleast one more message from the guest.
 297  *
 298  * range_count: The number of ranges in the range array.
 299  *
 300  * range_array: An array of page ranges returned to the host.
 301  *
 302  */
 303
 304 struct dm_balloon_response {
 305         struct dm_header hdr;
 306         __u32 reservedz;
 307         __u32 more_pages:1;
 308         __u32 range_count:31;
 309         union dm_mem_page_range range_array[];
 310 } __packed;
 311
 312 /*
 313  * Un-balloon message; this message is sent from the host
 314  * to the guest to give guest more memory.
 315  *
 316  * more_pages: If FALSE, this is the last message of the transaction.
 317  * if TRUE there will atleast one more message from the guest.
 318  *
 319  * reservedz: Reserved; must be set to zero.
 320  *
 321  * range_count: The number of ranges in the range array.
 322  *
 323  * range_array: An array of page ranges returned to the host.
 324  *
 325  */
 326
 327 struct dm_unballoon_request {
 328         struct dm_header hdr;
 329         __u32 more_pages:1;
 330         __u32 reservedz:31;
 331         __u32 range_count;
 332         union dm_mem_page_range range_array[];
 333 } __packed;
 334
 335 /*
 336  * Un-balloon response message; this message is sent from the guest
 337  * to the host in response to an unballoon request.
 338  *
 339  */
 340
 341 struct dm_unballoon_response {
 342         struct dm_header hdr;
 343 } __packed;
 344
 345
 346 /*
 347  * Hot add request message. Message sent from the host to the guest.
 348  *
 349  * mem_range: Memory range to hot add.
 350  *
 351  * On Linux we currently don't support this since we cannot hot add
 352  * arbitrary granularity of memory.
 353  */
 354
 355 struct dm_hot_add {
 356         struct dm_header hdr;
 357         union dm_mem_page_range range;
 358 } __packed;
 359
 360 /*
 361  * Hot add response message.
 362  * This message is sent by the guest to report the status of a hot add request.
 363  * If page_count is less than the requested page count, then the host should
 364  * assume all further hot add requests will fail, since this indicates that
 365  * the guest has hit an upper physical memory barrier.
 366  *
 367  * Hot adds may also fail due to low resources; in this case, the guest must
 368  * not complete this message until the hot add can succeed, and the host must
 369  * not send a new hot add request until the response is sent.
 370  * If VSC fails to hot add memory DYNMEM_NUMBER_OF_UNSUCCESSFUL_HOTADD_ATTEMPTS
 371  * times it fails the request.
 372  *
 373  *
 374  * page_count: number of pages that were successfully hot added.
 375  *
 376  * result: result of the operation 1: success, 0: failure.
 377  *
 378  */
 379
 380 struct dm_hot_add_response {
 381         struct dm_header hdr;
 382         __u32 page_count;
 383         __u32 result;
 384 } __packed;
 385
 386 /*
 387  * Types of information sent from host to the guest.
 388  */
 389
 390 enum dm_info_type {
 391         INFO_TYPE_MAX_PAGE_CNT = 0,
 392         MAX_INFO_TYPE
 393 };
 394
 395
 396 /*
 397  * Header for the information message.
 398  */
 399
 400 struct dm_info_header {
 401         enum dm_info_type type;
 402         __u32 data_size;
 403 } __packed;
 404
 405 /*
 406  * This message is sent from the host to the guest to pass
 407  * some relevant information (win8 addition).
 408  *
 409  * reserved: no used.
 410  * info_size: size of the information blob.
 411  * info: information blob.
 412  */
 413
 414 struct dm_info_msg {
 415         struct dm_header hdr;
 416         __u32 reserved;
 417         __u32 info_size;
 418         __u8  info[];
 419 };
 420
 421 /*
 422  * End protocol definitions.
 423  */
 424
 425 /*
 426  * State to manage hot adding memory into the guest.
 427  * The range start_pfn : end_pfn specifies the range
 428  * that the host has asked us to hot add. The range
 429  * start_pfn : ha_end_pfn specifies the range that we have
 430  * currently hot added. We hot add in multiples of 128M
 431  * chunks; it is possible that we may not be able to bring
 432  * online all the pages in the region. The range
 433  * covered_start_pfn:covered_end_pfn defines the pages that can
 434  * be brough online.
 435  */
 436
 437 struct hv_hotadd_state {
 438         struct list_head list;
 439         unsigned long start_pfn;
 440         unsigned long covered_start_pfn;
 441         unsigned long covered_end_pfn;
 442         unsigned long ha_end_pfn;
 443         unsigned long end_pfn;
 444         /*
 445          * A list of gaps.
 446          */
 447         struct list_head gap_list;
 448 };
 449
 450 struct hv_hotadd_gap {
 451         struct list_head list;
 452         unsigned long start_pfn;
 453         unsigned long end_pfn;
 454 };
 455
 456 struct balloon_state {
 457         __u32 num_pages;
 458         struct work_struct wrk;
 459 };
 460
 461 struct hot_add_wrk {
 462         union dm_mem_page_range ha_page_range;
 463         union dm_mem_page_range ha_region_range;
 464         struct work_struct wrk;
 465 };
 466
 467 static bool hot_add = true;
 468 static bool do_hot_add;
 469 /*
 470  * Delay reporting memory pressure by
 471  * the specified number of seconds.
 472  */
 473 static uint pressure_report_delay = 45;
 474
 475 /*
 476  * The last time we posted a pressure report to host.
 477  */
 478 static unsigned long last_post_time;
 479
 480 module_param(hot_add, bool, (S_IRUGO | S_IWUSR));
 481 MODULE_PARM_DESC(hot_add, "If set attempt memory hot_add");
 482
 483 module_param(pressure_report_delay, uint, (S_IRUGO | S_IWUSR));
 484 MODULE_PARM_DESC(pressure_report_delay, "Delay in secs in reporting pressure");
 485 static atomic_t trans_id = ATOMIC_INIT(0);
 486
 487 static int dm_ring_size = (5 * PAGE_SIZE);
 488
 489 /*
 490  * Driver specific state.
 491  */
 492
 493 enum hv_dm_state {
 494         DM_INITIALIZING = 0,
 495         DM_INITIALIZED,
 496         DM_BALLOON_UP,
 497         DM_BALLOON_DOWN,
 498         DM_HOT_ADD,
 499         DM_INIT_ERROR
 500 };
 501
 502
 503 static __u8 recv_buffer[PAGE_SIZE];
 504 static __u8 *send_buffer;
 505 #define PAGES_IN_2M     512
 506 #define HA_CHUNK (32 * 1024)
 507
 508 struct hv_dynmem_device {
 509         struct hv_device *dev;
 510         enum hv_dm_state state;
 511         struct completion host_event;
 512         struct completion config_event;
 513
 514         /*
 515          * Number of pages we have currently ballooned out.
 516          */
 517         unsigned int num_pages_ballooned;
 518         unsigned int num_pages_onlined;
 519         unsigned int num_pages_added;
 520
 521         /*
 522          * State to manage the ballooning (up) operation.
 523          */
 524         struct balloon_state balloon_wrk;
 525
 526         /*
 527          * State to execute the "hot-add" operation.
 528          */
 529         struct hot_add_wrk ha_wrk;
 530
 531         /*
 532          * This state tracks if the host has specified a hot-add
 533          * region.
 534          */
 535         bool host_specified_ha_region;
 536
 537         /*
 538          * State to synchronize hot-add.
 539          */
 540         struct completion  ol_waitevent;
 541         bool ha_waiting;
 542         /*
 543          * This thread handles hot-add
 544          * requests from the host as well as notifying
 545          * the host with regards to memory pressure in
 546          * the guest.
 547          */
 548         struct task_struct *thread;
 549
 550         /*
 551          * Protects ha_region_list, num_pages_onlined counter and individual
 552          * regions from ha_region_list.
 553          */
 554         spinlock_t ha_lock;
 555
 556         /*
 557          * A list of hot-add regions.
 558          */
 559         struct list_head ha_region_list;
 560
 561         /*
 562          * We start with the highest version we can support
 563          * and downgrade based on the host; we save here the
 564          * next version to try.
 565          */
 566         __u32 next_version;
 567
 568         /*
 569          * The negotiated version agreed by host.
 570          */
 571         __u32 version;
 572 };
 573
 574 static struct hv_dynmem_device dm_device;
 575
 576 static void post_status(struct hv_dynmem_device *dm);
 577
 578 #ifdef CONFIG_MEMORY_HOTPLUG
 579 static int hv_memory_notifier(struct notifier_block *nb, unsigned long val,
 580                               void *v)
 581 {
 582         struct memory_notify *mem = (struct memory_notify *)v;
 583         unsigned long flags;
 584
 585         switch (val) {
 586         case MEM_ONLINE:
 587                 spin_lock_irqsave(&dm_device.ha_lock, flags);
 588                 dm_device.num_pages_onlined += mem->nr_pages;
 589                 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
 590                 /* Fall through */
 591         case MEM_CANCEL_ONLINE:
 592                 if (dm_device.ha_waiting) {
 593                         dm_device.ha_waiting = false;
 594                         complete(&dm_device.ol_waitevent);
 595                 }
 596                 break;
 597
 598         case MEM_OFFLINE:
 599                 spin_lock_irqsave(&dm_device.ha_lock, flags);
 600                 dm_device.num_pages_onlined -= mem->nr_pages;
 601                 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
 602                 break;
 603         case MEM_GOING_ONLINE:
 604         case MEM_GOING_OFFLINE:
 605         case MEM_CANCEL_OFFLINE:
 606                 break;
 607         }
 608         return NOTIFY_OK;
 609 }
 610
 611 static struct notifier_block hv_memory_nb = {
 612         .notifier_call = hv_memory_notifier,
 613         .priority = 0
 614 };
 615
 616 /* Check if the particular page is backed and can be onlined and online it. */
 617 static void hv_page_online_one(struct hv_hotadd_state *has, struct page *pg)
 618 {
 619         unsigned long cur_start_pgp;
 620         unsigned long cur_end_pgp;
 621         struct hv_hotadd_gap *gap;
 622
 623         cur_start_pgp = (unsigned long)pfn_to_page(has->covered_start_pfn);
 624         cur_end_pgp = (unsigned long)pfn_to_page(has->covered_end_pfn);
 625
 626         /* The page is not backed. */
 627         if (((unsigned long)pg < cur_start_pgp) ||
 628             ((unsigned long)pg >= cur_end_pgp))
 629                 return;
 630
 631         /* Check for gaps. */
 632         list_for_each_entry(gap, &has->gap_list, list) {
 633                 cur_start_pgp = (unsigned long)
 634                         pfn_to_page(gap->start_pfn);
 635                 cur_end_pgp = (unsigned long)
 636                         pfn_to_page(gap->end_pfn);
 637                 if (((unsigned long)pg >= cur_start_pgp) &&
 638                     ((unsigned long)pg < cur_end_pgp)) {
 639                         return;
 640                 }
 641         }
 642
 643         /* This frame is currently backed; online the page. */
 644         __online_page_set_limits(pg);
 645         __online_page_increment_counters(pg);
 646         __online_page_free(pg);
 647 }
 648
 649 static void hv_bring_pgs_online(struct hv_hotadd_state *has,
 650                                 unsigned long start_pfn, unsigned long size)
 651 {
 652         int i;
 653
 654         pr_debug("Online %lu pages starting at pfn 0x%lx\n", size, start_pfn);
 655         for (i = 0; i < size; i++)
 656                 hv_page_online_one(has, pfn_to_page(start_pfn + i));
 657 }
 658
 659 static void hv_mem_hot_add(unsigned long start, unsigned long size,
 660                                 unsigned long pfn_count,
 661                                 struct hv_hotadd_state *has)
 662 {
 663         int ret = 0;
 664         int i, nid;
 665         unsigned long start_pfn;
 666         unsigned long processed_pfn;
 667         unsigned long total_pfn = pfn_count;
 668         unsigned long flags;
 669
 670         for (i = 0; i < (size/HA_CHUNK); i++) {
 671                 start_pfn = start + (i * HA_CHUNK);
 672
 673                 spin_lock_irqsave(&dm_device.ha_lock, flags);
 674                 has->ha_end_pfn +=  HA_CHUNK;
 675
 676                 if (total_pfn > HA_CHUNK) {
 677                         processed_pfn = HA_CHUNK;
 678                         total_pfn -= HA_CHUNK;
 679                 } else {
 680                         processed_pfn = total_pfn;
 681                         total_pfn = 0;
 682                 }
 683
 684                 has->covered_end_pfn +=  processed_pfn;
 685                 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
 686
 687                 init_completion(&dm_device.ol_waitevent);
 688                 dm_device.ha_waiting = !memhp_auto_online;
 689
 690                 nid = memory_add_physaddr_to_nid(PFN_PHYS(start_pfn));
 691                 ret = add_memory(nid, PFN_PHYS((start_pfn)),
 692                                 (HA_CHUNK << PAGE_SHIFT));
 693
 694                 if (ret) {
 695                         pr_warn("hot_add memory failed error is %d\n", ret);
 696                         if (ret == -EEXIST) {
 697                                 /*
 698                                  * This error indicates that the error
 699                                  * is not a transient failure. This is the
 700                                  * case where the guest's physical address map
 701                                  * precludes hot adding memory. Stop all further
 702                                  * memory hot-add.
 703                                  */
 704                                 do_hot_add = false;
 705                         }
 706                         spin_lock_irqsave(&dm_device.ha_lock, flags);
 707                         has->ha_end_pfn -= HA_CHUNK;
 708                         has->covered_end_pfn -=  processed_pfn;
 709                         spin_unlock_irqrestore(&dm_device.ha_lock, flags);
 710                         break;
 711                 }
 712
 713                 /*
 714                  * Wait for the memory block to be onlined when memory onlining
 715                  * is done outside of kernel (memhp_auto_online). Since the hot
 716                  * add has succeeded, it is ok to proceed even if the pages in
 717                  * the hot added region have not been "onlined" within the
 718                  * allowed time.
 719                  */
 720                 if (dm_device.ha_waiting)
 721                         wait_for_completion_timeout(&dm_device.ol_waitevent,
 722                                                     5*HZ);
 723                 post_status(&dm_device);
 724         }
 725
 726         return;
 727 }
 728
 729 static void hv_online_page(struct page *pg)
 730 {
 731         struct hv_hotadd_state *has;
 732         unsigned long cur_start_pgp;
 733         unsigned long cur_end_pgp;
 734         unsigned long flags;
 735
 736         spin_lock_irqsave(&dm_device.ha_lock, flags);
 737         list_for_each_entry(has, &dm_device.ha_region_list, list) {
 738                 cur_start_pgp = (unsigned long)
 739                         pfn_to_page(has->start_pfn);
 740                 cur_end_pgp = (unsigned long)pfn_to_page(has->end_pfn);
 741
 742                 /* The page belongs to a different HAS. */
 743                 if (((unsigned long)pg < cur_start_pgp) ||
 744                     ((unsigned long)pg >= cur_end_pgp))
 745                         continue;
 746
 747                 hv_page_online_one(has, pg);
 748                 break;
 749         }
 750         spin_unlock_irqrestore(&dm_device.ha_lock, flags);
 751 }
 752
 753 static int pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt)
 754 {
 755         struct hv_hotadd_state *has;
 756         struct hv_hotadd_gap *gap;
 757         unsigned long residual, new_inc;
 758         int ret = 0;
 759         unsigned long flags;
 760
 761         spin_lock_irqsave(&dm_device.ha_lock, flags);
 762         list_for_each_entry(has, &dm_device.ha_region_list, list) {
 763                 /*
 764                  * If the pfn range we are dealing with is not in the current
 765                  * "hot add block", move on.
 766                  */
 767                 if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn)
 768                         continue;
 769
 770                 /*
 771                  * If the current start pfn is not where the covered_end
 772                  * is, create a gap and update covered_end_pfn.
 773                  */
 774                 if (has->covered_end_pfn != start_pfn) {
 775                         gap = kzalloc(sizeof(struct hv_hotadd_gap), GFP_ATOMIC);
 776                         if (!gap) {
 777                                 ret = -ENOMEM;
 778                                 break;
 779                         }
 780
 781                         INIT_LIST_HEAD(&gap->list);
 782                         gap->start_pfn = has->covered_end_pfn;
 783                         gap->end_pfn = start_pfn;
 784                         list_add_tail(&gap->list, &has->gap_list);
 785
 786                         has->covered_end_pfn = start_pfn;
 787                 }
 788
 789                 /*
 790                  * If the current hot add-request extends beyond
 791                  * our current limit; extend it.
 792                  */
 793                 if ((start_pfn + pfn_cnt) > has->end_pfn) {
 794                         residual = (start_pfn + pfn_cnt - has->end_pfn);
 795                         /*
 796                          * Extend the region by multiples of HA_CHUNK.
 797                          */
 798                         new_inc = (residual / HA_CHUNK) * HA_CHUNK;
 799                         if (residual % HA_CHUNK)
 800                                 new_inc += HA_CHUNK;
 801
 802                         has->end_pfn += new_inc;
 803                 }
 804
 805                 ret = 1;
 806                 break;
 807         }
 808         spin_unlock_irqrestore(&dm_device.ha_lock, flags);
 809
 810         return ret;
 811 }
 812
 813 static unsigned long handle_pg_range(unsigned long pg_start,
 814                                         unsigned long pg_count)
 815 {
 816         unsigned long start_pfn = pg_start;
 817         unsigned long pfn_cnt = pg_count;
 818         unsigned long size;
 819         struct hv_hotadd_state *has;
 820         unsigned long pgs_ol = 0;
 821         unsigned long old_covered_state;
 822         unsigned long res = 0, flags;
 823
 824         pr_debug("Hot adding %lu pages starting at pfn 0x%lx.\n", pg_count,
 825                 pg_start);
 826
 827         spin_lock_irqsave(&dm_device.ha_lock, flags);
 828         list_for_each_entry(has, &dm_device.ha_region_list, list) {
 829                 /*
 830                  * If the pfn range we are dealing with is not in the current
 831                  * "hot add block", move on.
 832                  */
 833                 if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn)
 834                         continue;
 835
 836                 old_covered_state = has->covered_end_pfn;
 837
 838                 if (start_pfn < has->ha_end_pfn) {
 839                         /*
 840                          * This is the case where we are backing pages
 841                          * in an already hot added region. Bring
 842                          * these pages online first.
 843                          */
 844                         pgs_ol = has->ha_end_pfn - start_pfn;
 845                         if (pgs_ol > pfn_cnt)
 846                                 pgs_ol = pfn_cnt;
 847
 848                         has->covered_end_pfn +=  pgs_ol;
 849                         pfn_cnt -= pgs_ol;
 850                         /*
 851                          * Check if the corresponding memory block is already
 852                          * online by checking its last previously backed page.
 853                          * In case it is we need to bring rest (which was not
 854                          * backed previously) online too.
 855                          */
 856                         if (start_pfn > has->start_pfn &&
 857                             !PageReserved(pfn_to_page(start_pfn - 1)))
 858                                 hv_bring_pgs_online(has, start_pfn, pgs_ol);
 859
 860                 }
 861
 862                 if ((has->ha_end_pfn < has->end_pfn) && (pfn_cnt > 0)) {
 863                         /*
 864                          * We have some residual hot add range
 865                          * that needs to be hot added; hot add
 866                          * it now. Hot add a multiple of
 867                          * of HA_CHUNK that fully covers the pages
 868                          * we have.
 869                          */
 870                         size = (has->end_pfn - has->ha_end_pfn);
 871                         if (pfn_cnt <= size) {
 872                                 size = ((pfn_cnt / HA_CHUNK) * HA_CHUNK);
 873                                 if (pfn_cnt % HA_CHUNK)
 874                                         size += HA_CHUNK;
 875                         } else {
 876                                 pfn_cnt = size;
 877                         }
 878                         spin_unlock_irqrestore(&dm_device.ha_lock, flags);
 879                         hv_mem_hot_add(has->ha_end_pfn, size, pfn_cnt, has);
 880                         spin_lock_irqsave(&dm_device.ha_lock, flags);
 881                 }
 882                 /*
 883                  * If we managed to online any pages that were given to us,
 884                  * we declare success.
 885                  */
 886                 res = has->covered_end_pfn - old_covered_state;
 887                 break;
 888         }
 889         spin_unlock_irqrestore(&dm_device.ha_lock, flags);
 890
 891         return res;
 892 }
 893
 894 static unsigned long process_hot_add(unsigned long pg_start,
 895                                         unsigned long pfn_cnt,
 896                                         unsigned long rg_start,
 897                                         unsigned long rg_size)
 898 {
 899         struct hv_hotadd_state *ha_region = NULL;
 900         int covered;
 901         unsigned long flags;
 902
 903         if (pfn_cnt == 0)
 904                 return 0;
 905
 906         if (!dm_device.host_specified_ha_region) {
 907                 covered = pfn_covered(pg_start, pfn_cnt);
 908                 if (covered < 0)
 909                         return 0;
 910
 911                 if (covered)
 912                         goto do_pg_range;
 913         }
 914
 915         /*
 916          * If the host has specified a hot-add range; deal with it first.
 917          */
 918
 919         if (rg_size != 0) {
 920                 ha_region = kzalloc(sizeof(struct hv_hotadd_state), GFP_KERNEL);
 921                 if (!ha_region)
 922                         return 0;
 923
 924                 INIT_LIST_HEAD(&ha_region->list);
 925                 INIT_LIST_HEAD(&ha_region->gap_list);
 926
 927                 ha_region->start_pfn = rg_start;
 928                 ha_region->ha_end_pfn = rg_start;
 929                 ha_region->covered_start_pfn = pg_start;
 930                 ha_region->covered_end_pfn = pg_start;
 931                 ha_region->end_pfn = rg_start + rg_size;
 932
 933                 spin_lock_irqsave(&dm_device.ha_lock, flags);
 934                 list_add_tail(&ha_region->list, &dm_device.ha_region_list);
 935                 spin_unlock_irqrestore(&dm_device.ha_lock, flags);
 936         }
 937
 938 do_pg_range:
 939         /*
 940          * Process the page range specified; bringing them
 941          * online if possible.
 942          */
 943         return handle_pg_range(pg_start, pfn_cnt);
 944 }
 945
 946 #endif
 947
 948 static void hot_add_req(struct work_struct *dummy)
 949 {
 950         struct dm_hot_add_response resp;
 951 #ifdef CONFIG_MEMORY_HOTPLUG
 952         unsigned long pg_start, pfn_cnt;
 953         unsigned long rg_start, rg_sz;
 954 #endif
 955         struct hv_dynmem_device *dm = &dm_device;
 956
 957         memset(&resp, 0, sizeof(struct dm_hot_add_response));
 958         resp.hdr.type = DM_MEM_HOT_ADD_RESPONSE;
 959         resp.hdr.size = sizeof(struct dm_hot_add_response);
 960
 961 #ifdef CONFIG_MEMORY_HOTPLUG
 962         pg_start = dm->ha_wrk.ha_page_range.finfo.start_page;
 963         pfn_cnt = dm->ha_wrk.ha_page_range.finfo.page_cnt;
 964
 965         rg_start = dm->ha_wrk.ha_region_range.finfo.start_page;
 966         rg_sz = dm->ha_wrk.ha_region_range.finfo.page_cnt;
 967
 968         if ((rg_start == 0) && (!dm->host_specified_ha_region)) {
 969                 unsigned long region_size;
 970                 unsigned long region_start;
 971
 972                 /*
 973                  * The host has not specified the hot-add region.
 974                  * Based on the hot-add page range being specified,
 975                  * compute a hot-add region that can cover the pages
 976                  * that need to be hot-added while ensuring the alignment
 977                  * and size requirements of Linux as it relates to hot-add.
 978                  */
 979                 region_start = pg_start;
 980                 region_size = (pfn_cnt / HA_CHUNK) * HA_CHUNK;
 981                 if (pfn_cnt % HA_CHUNK)
 982                         region_size += HA_CHUNK;
 983
 984                 region_start = (pg_start / HA_CHUNK) * HA_CHUNK;
 985
 986                 rg_start = region_start;
 987                 rg_sz = region_size;
 988         }
 989
 990         if (do_hot_add)
 991                 resp.page_count = process_hot_add(pg_start, pfn_cnt,
 992                                                 rg_start, rg_sz);
 993
 994         dm->num_pages_added += resp.page_count;
 995 #endif
 996         /*
 997          * The result field of the response structure has the
 998          * following semantics:
 999          *
1000          * 1. If all or some pages hot-added: Guest should return success.
1001          *
1002          * 2. If no pages could be hot-added:
1003          *
1004          * If the guest returns success, then the host
1005          * will not attempt any further hot-add operations. This
1006          * signifies a permanent failure.
1007          *
1008          * If the guest returns failure, then this failure will be
1009          * treated as a transient failure and the host may retry the
1010          * hot-add operation after some delay.
1011          */
1012         if (resp.page_count > 0)
1013                 resp.result = 1;
1014         else if (!do_hot_add)
1015                 resp.result = 1;
1016         else
1017                 resp.result = 0;
1018
1019         if (!do_hot_add || (resp.page_count == 0))
1020                 pr_info("Memory hot add failed\n");
1021
1022         dm->state = DM_INITIALIZED;
1023         resp.hdr.trans_id = atomic_inc_return(&trans_id);
1024         vmbus_sendpacket(dm->dev->channel, &resp,
1025                         sizeof(struct dm_hot_add_response),
1026                         (unsigned long)NULL,
1027                         VM_PKT_DATA_INBAND, 0);
1028 }
1029
1030 static void process_info(struct hv_dynmem_device *dm, struct dm_info_msg *msg)
1031 {
1032         struct dm_info_header *info_hdr;
1033
1034         info_hdr = (struct dm_info_header *)msg->info;
1035
1036         switch (info_hdr->type) {
1037         case INFO_TYPE_MAX_PAGE_CNT:
1038                 if (info_hdr->data_size == sizeof(__u64)) {
1039                         __u64 *max_page_count = (__u64 *)&info_hdr[1];
1040
1041                         pr_info("INFO_TYPE_MAX_PAGE_CNT = %llu\n",
1042                                 *max_page_count);
1043                 }
1044
1045                 break;
1046         default:
1047                 pr_info("Received Unknown type: %d\n", info_hdr->type);
1048         }
1049 }
1050
1051 static unsigned long compute_balloon_floor(void)
1052 {
1053         unsigned long min_pages;
1054 #define MB2PAGES(mb) ((mb) << (20 - PAGE_SHIFT))
1055         /* Simple continuous piecewiese linear function:
1056          *  max MiB -> min MiB  gradient
1057          *       0         0
1058          *      16        16
1059          *      32        24
1060          *     128        72    (1/2)
1061          *     512       168    (1/4)
1062          *    2048       360    (1/8)
1063          *    8192       744    (1/16)
1064          *   32768      1512    (1/32)
1065          */
1066         if (totalram_pages < MB2PAGES(128))
1067                 min_pages = MB2PAGES(8) + (totalram_pages >> 1);
1068         else if (totalram_pages < MB2PAGES(512))
1069                 min_pages = MB2PAGES(40) + (totalram_pages >> 2);
1070         else if (totalram_pages < MB2PAGES(2048))
1071                 min_pages = MB2PAGES(104) + (totalram_pages >> 3);
1072         else if (totalram_pages < MB2PAGES(8192))
1073                 min_pages = MB2PAGES(232) + (totalram_pages >> 4);
1074         else
1075                 min_pages = MB2PAGES(488) + (totalram_pages >> 5);
1076 #undef MB2PAGES
1077         return min_pages;
1078 }
1079
1080 /*
1081  * Post our status as it relates memory pressure to the
1082  * host. Host expects the guests to post this status
1083  * periodically at 1 second intervals.
1084  *
1085  * The metrics specified in this protocol are very Windows
1086  * specific and so we cook up numbers here to convey our memory
1087  * pressure.
1088  */
1089
1090 static void post_status(struct hv_dynmem_device *dm)
1091 {
1092         struct dm_status status;
1093         unsigned long now = jiffies;
1094         unsigned long last_post = last_post_time;
1095
1096         if (pressure_report_delay > 0) {
1097                 --pressure_report_delay;
1098                 return;
1099         }
1100
1101         if (!time_after(now, (last_post_time + HZ)))
1102                 return;
1103
1104         memset(&status, 0, sizeof(struct dm_status));
1105         status.hdr.type = DM_STATUS_REPORT;
1106         status.hdr.size = sizeof(struct dm_status);
1107         status.hdr.trans_id = atomic_inc_return(&trans_id);
1108
1109         /*
1110          * The host expects the guest to report free and committed memory.
1111          * Furthermore, the host expects the pressure information to include
1112          * the ballooned out pages. For a given amount of memory that we are
1113          * managing we need to compute a floor below which we should not
1114          * balloon. Compute this and add it to the pressure report.
1115          * We also need to report all offline pages (num_pages_added -
1116          * num_pages_onlined) as committed to the host, otherwise it can try
1117          * asking us to balloon them out.
1118          */
1119         status.num_avail = si_mem_available();
1120         status.num_committed = vm_memory_committed() +
1121                 dm->num_pages_ballooned +
1122                 (dm->num_pages_added > dm->num_pages_onlined ?
1123                  dm->num_pages_added - dm->num_pages_onlined : 0) +
1124                 compute_balloon_floor();
1125
1126         /*
1127          * If our transaction ID is no longer current, just don't
1128          * send the status. This can happen if we were interrupted
1129          * after we picked our transaction ID.
1130          */
1131         if (status.hdr.trans_id != atomic_read(&trans_id))
1132                 return;
1133
1134         /*
1135          * If the last post time that we sampled has changed,
1136          * we have raced, don't post the status.
1137          */
1138         if (last_post != last_post_time)
1139                 return;
1140
1141         last_post_time = jiffies;
1142         vmbus_sendpacket(dm->dev->channel, &status,
1143                                 sizeof(struct dm_status),
1144                                 (unsigned long)NULL,
1145                                 VM_PKT_DATA_INBAND, 0);
1146
1147 }
1148
1149 static void free_balloon_pages(struct hv_dynmem_device *dm,
1150                          union dm_mem_page_range *range_array)
1151 {
1152         int num_pages = range_array->finfo.page_cnt;
1153         __u64 start_frame = range_array->finfo.start_page;
1154         struct page *pg;
1155         int i;
1156
1157         for (i = 0; i < num_pages; i++) {
1158                 pg = pfn_to_page(i + start_frame);
1159                 __free_page(pg);
1160                 dm->num_pages_ballooned--;
1161         }
1162 }
1163
1164
1165
1166 static unsigned int alloc_balloon_pages(struct hv_dynmem_device *dm,
1167                                         unsigned int num_pages,
1168                                         struct dm_balloon_response *bl_resp,
1169                                         int alloc_unit)
1170 {
1171         unsigned int i = 0;
1172         struct page *pg;
1173
1174         if (num_pages < alloc_unit)
1175                 return 0;
1176
1177         for (i = 0; (i * alloc_unit) < num_pages; i++) {
1178                 if (bl_resp->hdr.size + sizeof(union dm_mem_page_range) >
1179                         PAGE_SIZE)
1180                         return i * alloc_unit;
1181
1182                 /*
1183                  * We execute this code in a thread context. Furthermore,
1184                  * we don't want the kernel to try too hard.
1185                  */
1186                 pg = alloc_pages(GFP_HIGHUSER | __GFP_NORETRY |
1187                                 __GFP_NOMEMALLOC | __GFP_NOWARN,
1188                                 get_order(alloc_unit << PAGE_SHIFT));
1189
1190                 if (!pg)
1191                         return i * alloc_unit;
1192
1193                 dm->num_pages_ballooned += alloc_unit;
1194
1195                 /*
1196                  * If we allocatted 2M pages; split them so we
1197                  * can free them in any order we get.
1198                  */
1199
1200                 if (alloc_unit != 1)
1201                         split_page(pg, get_order(alloc_unit << PAGE_SHIFT));
1202
1203                 bl_resp->range_count++;
1204                 bl_resp->range_array[i].finfo.start_page =
1205                         page_to_pfn(pg);
1206                 bl_resp->range_array[i].finfo.page_cnt = alloc_unit;
1207                 bl_resp->hdr.size += sizeof(union dm_mem_page_range);
1208
1209         }
1210
1211         return num_pages;
1212 }
1213
1214 static void balloon_up(struct work_struct *dummy)
1215 {
1216         unsigned int num_pages = dm_device.balloon_wrk.num_pages;
1217         unsigned int num_ballooned = 0;
1218         struct dm_balloon_response *bl_resp;
1219         int alloc_unit;
1220         int ret;
1221         bool done = false;
1222         int i;
1223         long avail_pages;
1224         unsigned long floor;
1225
1226         /* The host balloons pages in 2M granularity. */
1227         WARN_ON_ONCE(num_pages % PAGES_IN_2M != 0);
1228
1229         /*
1230          * We will attempt 2M allocations. However, if we fail to
1231          * allocate 2M chunks, we will go back to 4k allocations.
1232          */
1233         alloc_unit = 512;
1234
1235         avail_pages = si_mem_available();
1236         floor = compute_balloon_floor();
1237
1238         /* Refuse to balloon below the floor, keep the 2M granularity. */
1239         if (avail_pages < num_pages || avail_pages - num_pages < floor) {
1240                 pr_warn("Balloon request will be partially fulfilled. %s\n",
1241                         avail_pages < num_pages ? "Not enough memory." :
1242                         "Balloon floor reached.");
1243
1244                 num_pages = avail_pages > floor ? (avail_pages - floor) : 0;
1245                 num_pages -= num_pages % PAGES_IN_2M;
1246         }
1247
1248         while (!done) {
1249                 bl_resp = (struct dm_balloon_response *)send_buffer;
1250                 memset(send_buffer, 0, PAGE_SIZE);
1251                 bl_resp->hdr.type = DM_BALLOON_RESPONSE;
1252                 bl_resp->hdr.size = sizeof(struct dm_balloon_response);
1253                 bl_resp->more_pages = 1;
1254
1255                 num_pages -= num_ballooned;
1256                 num_ballooned = alloc_balloon_pages(&dm_device, num_pages,
1257                                                     bl_resp, alloc_unit);
1258
1259                 if (alloc_unit != 1 && num_ballooned == 0) {
1260                         alloc_unit = 1;
1261                         continue;
1262                 }
1263
1264                 if (num_ballooned == 0 || num_ballooned == num_pages) {
1265                         pr_debug("Ballooned %u out of %u requested pages.\n",
1266                                 num_pages, dm_device.balloon_wrk.num_pages);
1267
1268                         bl_resp->more_pages = 0;
1269                         done = true;
1270                         dm_device.state = DM_INITIALIZED;
1271                 }
1272
1273                 /*
1274                  * We are pushing a lot of data through the channel;
1275                  * deal with transient failures caused because of the
1276                  * lack of space in the ring buffer.
1277                  */
1278
1279                 do {
1280                         bl_resp->hdr.trans_id = atomic_inc_return(&trans_id);
1281                         ret = vmbus_sendpacket(dm_device.dev->channel,
1282                                                 bl_resp,
1283                                                 bl_resp->hdr.size,
1284                                                 (unsigned long)NULL,
1285                                                 VM_PKT_DATA_INBAND, 0);
1286
1287                         if (ret == -EAGAIN)
1288                                 msleep(20);
1289                         post_status(&dm_device);
1290                 } while (ret == -EAGAIN);
1291
1292                 if (ret) {
1293                         /*
1294                          * Free up the memory we allocatted.
1295                          */
1296                         pr_info("Balloon response failed\n");
1297
1298                         for (i = 0; i < bl_resp->range_count; i++)
1299                                 free_balloon_pages(&dm_device,
1300                                                  &bl_resp->range_array[i]);
1301
1302                         done = true;
1303                 }
1304         }
1305
1306 }
1307
1308 static void balloon_down(struct hv_dynmem_device *dm,
1309                         struct dm_unballoon_request *req)
1310 {
1311         union dm_mem_page_range *range_array = req->range_array;
1312         int range_count = req->range_count;
1313         struct dm_unballoon_response resp;
1314         int i;
1315         unsigned int prev_pages_ballooned = dm->num_pages_ballooned;
1316
1317         for (i = 0; i < range_count; i++) {
1318                 free_balloon_pages(dm, &range_array[i]);
1319                 complete(&dm_device.config_event);
1320         }
1321
1322         pr_debug("Freed %u ballooned pages.\n",
1323                 prev_pages_ballooned - dm->num_pages_ballooned);
1324
1325         if (req->more_pages == 1)
1326                 return;
1327
1328         memset(&resp, 0, sizeof(struct dm_unballoon_response));
1329         resp.hdr.type = DM_UNBALLOON_RESPONSE;
1330         resp.hdr.trans_id = atomic_inc_return(&trans_id);
1331         resp.hdr.size = sizeof(struct dm_unballoon_response);
1332
1333         vmbus_sendpacket(dm_device.dev->channel, &resp,
1334                                 sizeof(struct dm_unballoon_response),
1335                                 (unsigned long)NULL,
1336                                 VM_PKT_DATA_INBAND, 0);
1337
1338         dm->state = DM_INITIALIZED;
1339 }
1340
1341 static void balloon_onchannelcallback(void *context);
1342
1343 static int dm_thread_func(void *dm_dev)
1344 {
1345         struct hv_dynmem_device *dm = dm_dev;
1346
1347         while (!kthread_should_stop()) {
1348                 wait_for_completion_interruptible_timeout(
1349                                                 &dm_device.config_event, 1*HZ);
1350                 /*
1351                  * The host expects us to post information on the memory
1352                  * pressure every second.
1353                  */
1354                 reinit_completion(&dm_device.config_event);
1355                 post_status(dm);
1356         }
1357
1358         return 0;
1359 }
1360
1361
1362 static void version_resp(struct hv_dynmem_device *dm,
1363                         struct dm_version_response *vresp)
1364 {
1365         struct dm_version_request version_req;
1366         int ret;
1367
1368         if (vresp->is_accepted) {
1369                 /*
1370                  * We are done; wakeup the
1371                  * context waiting for version
1372                  * negotiation.
1373                  */
1374                 complete(&dm->host_event);
1375                 return;
1376         }
1377         /*
1378          * If there are more versions to try, continue
1379          * with negotiations; if not
1380          * shutdown the service since we are not able
1381          * to negotiate a suitable version number
1382          * with the host.
1383          */
1384         if (dm->next_version == 0)
1385                 goto version_error;
1386
1387         memset(&version_req, 0, sizeof(struct dm_version_request));
1388         version_req.hdr.type = DM_VERSION_REQUEST;
1389         version_req.hdr.size = sizeof(struct dm_version_request);
1390         version_req.hdr.trans_id = atomic_inc_return(&trans_id);
1391         version_req.version.version = dm->next_version;
1392         dm->version = version_req.version.version;
1393
1394         /*
1395          * Set the next version to try in case current version fails.
1396          * Win7 protocol ought to be the last one to try.
1397          */
1398         switch (version_req.version.version) {
1399         case DYNMEM_PROTOCOL_VERSION_WIN8:
1400                 dm->next_version = DYNMEM_PROTOCOL_VERSION_WIN7;
1401                 version_req.is_last_attempt = 0;
1402                 break;
1403         default:
1404                 dm->next_version = 0;
1405                 version_req.is_last_attempt = 1;
1406         }
1407
1408         ret = vmbus_sendpacket(dm->dev->channel, &version_req,
1409                                 sizeof(struct dm_version_request),
1410                                 (unsigned long)NULL,
1411                                 VM_PKT_DATA_INBAND, 0);
1412
1413         if (ret)
1414                 goto version_error;
1415
1416         return;
1417
1418 version_error:
1419         dm->state = DM_INIT_ERROR;
1420         complete(&dm->host_event);
1421 }
1422
1423 static void cap_resp(struct hv_dynmem_device *dm,
1424                         struct dm_capabilities_resp_msg *cap_resp)
1425 {
1426         if (!cap_resp->is_accepted) {
1427                 pr_info("Capabilities not accepted by host\n");
1428                 dm->state = DM_INIT_ERROR;
1429         }
1430         complete(&dm->host_event);
1431 }
1432
1433 static void balloon_onchannelcallback(void *context)
1434 {
1435         struct hv_device *dev = context;
1436         u32 recvlen;
1437         u64 requestid;
1438         struct dm_message *dm_msg;
1439         struct dm_header *dm_hdr;
1440         struct hv_dynmem_device *dm = hv_get_drvdata(dev);
1441         struct dm_balloon *bal_msg;
1442         struct dm_hot_add *ha_msg;
1443         union dm_mem_page_range *ha_pg_range;
1444         union dm_mem_page_range *ha_region;
1445
1446         memset(recv_buffer, 0, sizeof(recv_buffer));
1447         vmbus_recvpacket(dev->channel, recv_buffer,
1448                          PAGE_SIZE, &recvlen, &requestid);
1449
1450         if (recvlen > 0) {
1451                 dm_msg = (struct dm_message *)recv_buffer;
1452                 dm_hdr = &dm_msg->hdr;
1453
1454                 switch (dm_hdr->type) {
1455                 case DM_VERSION_RESPONSE:
1456                         version_resp(dm,
1457                                  (struct dm_version_response *)dm_msg);
1458                         break;
1459
1460                 case DM_CAPABILITIES_RESPONSE:
1461                         cap_resp(dm,
1462                                  (struct dm_capabilities_resp_msg *)dm_msg);
1463                         break;
1464
1465                 case DM_BALLOON_REQUEST:
1466                         if (dm->state == DM_BALLOON_UP)
1467                                 pr_warn("Currently ballooning\n");
1468                         bal_msg = (struct dm_balloon *)recv_buffer;
1469                         dm->state = DM_BALLOON_UP;
1470                         dm_device.balloon_wrk.num_pages = bal_msg->num_pages;
1471                         schedule_work(&dm_device.balloon_wrk.wrk);
1472                         break;
1473
1474                 case DM_UNBALLOON_REQUEST:
1475                         dm->state = DM_BALLOON_DOWN;
1476                         balloon_down(dm,
1477                                  (struct dm_unballoon_request *)recv_buffer);
1478                         break;
1479
1480                 case DM_MEM_HOT_ADD_REQUEST:
1481                         if (dm->state == DM_HOT_ADD)
1482                                 pr_warn("Currently hot-adding\n");
1483                         dm->state = DM_HOT_ADD;
1484                         ha_msg = (struct dm_hot_add *)recv_buffer;
1485                         if (ha_msg->hdr.size == sizeof(struct dm_hot_add)) {
1486                                 /*
1487                                  * This is a normal hot-add request specifying
1488                                  * hot-add memory.
1489                                  */
1490                                 dm->host_specified_ha_region = false;
1491                                 ha_pg_range = &ha_msg->range;
1492                                 dm->ha_wrk.ha_page_range = *ha_pg_range;
1493                                 dm->ha_wrk.ha_region_range.page_range = 0;
1494                         } else {
1495                                 /*
1496                                  * Host is specifying that we first hot-add
1497                                  * a region and then partially populate this
1498                                  * region.
1499                                  */
1500                                 dm->host_specified_ha_region = true;
1501                                 ha_pg_range = &ha_msg->range;
1502                                 ha_region = &ha_pg_range[1];
1503                                 dm->ha_wrk.ha_page_range = *ha_pg_range;
1504                                 dm->ha_wrk.ha_region_range = *ha_region;
1505                         }
1506                         schedule_work(&dm_device.ha_wrk.wrk);
1507                         break;
1508
1509                 case DM_INFO_MESSAGE:
1510                         process_info(dm, (struct dm_info_msg *)dm_msg);
1511                         break;
1512
1513                 default:
1514                         pr_err("Unhandled message: type: %d\n", dm_hdr->type);
1515
1516                 }
1517         }
1518
1519 }
1520
1521 static int balloon_probe(struct hv_device *dev,
1522                         const struct hv_vmbus_device_id *dev_id)
1523 {
1524         int ret;
1525         unsigned long t;
1526         struct dm_version_request version_req;
1527         struct dm_capabilities cap_msg;
1528
1529 #ifdef CONFIG_MEMORY_HOTPLUG
1530         do_hot_add = hot_add;
1531 #else
1532         do_hot_add = false;
1533 #endif
1534
1535         /*
1536          * First allocate a send buffer.
1537          */
1538
1539         send_buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
1540         if (!send_buffer)
1541                 return -ENOMEM;
1542
1543         ret = vmbus_open(dev->channel, dm_ring_size, dm_ring_size, NULL, 0,
1544                         balloon_onchannelcallback, dev);
1545
1546         if (ret)
1547                 goto probe_error0;
1548
1549         dm_device.dev = dev;
1550         dm_device.state = DM_INITIALIZING;
1551         dm_device.next_version = DYNMEM_PROTOCOL_VERSION_WIN8;
1552         init_completion(&dm_device.host_event);
1553         init_completion(&dm_device.config_event);
1554         INIT_LIST_HEAD(&dm_device.ha_region_list);
1555         spin_lock_init(&dm_device.ha_lock);
1556         INIT_WORK(&dm_device.balloon_wrk.wrk, balloon_up);
1557         INIT_WORK(&dm_device.ha_wrk.wrk, hot_add_req);
1558         dm_device.host_specified_ha_region = false;
1559
1560         dm_device.thread =
1561                  kthread_run(dm_thread_func, &dm_device, "hv_balloon");
1562         if (IS_ERR(dm_device.thread)) {
1563                 ret = PTR_ERR(dm_device.thread);
1564                 goto probe_error1;
1565         }
1566
1567 #ifdef CONFIG_MEMORY_HOTPLUG
1568         set_online_page_callback(&hv_online_page);
1569         register_memory_notifier(&hv_memory_nb);
1570 #endif
1571
1572         hv_set_drvdata(dev, &dm_device);
1573         /*
1574          * Initiate the hand shake with the host and negotiate
1575          * a version that the host can support. We start with the
1576          * highest version number and go down if the host cannot
1577          * support it.
1578          */
1579         memset(&version_req, 0, sizeof(struct dm_version_request));
1580         version_req.hdr.type = DM_VERSION_REQUEST;
1581         version_req.hdr.size = sizeof(struct dm_version_request);
1582         version_req.hdr.trans_id = atomic_inc_return(&trans_id);
1583         version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN10;
1584         version_req.is_last_attempt = 0;
1585         dm_device.version = version_req.version.version;
1586
1587         ret = vmbus_sendpacket(dev->channel, &version_req,
1588                                 sizeof(struct dm_version_request),
1589                                 (unsigned long)NULL,
1590                                 VM_PKT_DATA_INBAND, 0);
1591         if (ret)
1592                 goto probe_error2;
1593
1594         t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ);
1595         if (t == 0) {
1596                 ret = -ETIMEDOUT;
1597                 goto probe_error2;
1598         }
1599
1600         /*
1601          * If we could not negotiate a compatible version with the host
1602          * fail the probe function.
1603          */
1604         if (dm_device.state == DM_INIT_ERROR) {
1605                 ret = -ETIMEDOUT;
1606                 goto probe_error2;
1607         }
1608
1609         pr_info("Using Dynamic Memory protocol version %u.%u\n",
1610                 DYNMEM_MAJOR_VERSION(dm_device.version),
1611                 DYNMEM_MINOR_VERSION(dm_device.version));
1612
1613         /*
1614          * Now submit our capabilities to the host.
1615          */
1616         memset(&cap_msg, 0, sizeof(struct dm_capabilities));
1617         cap_msg.hdr.type = DM_CAPABILITIES_REPORT;
1618         cap_msg.hdr.size = sizeof(struct dm_capabilities);
1619         cap_msg.hdr.trans_id = atomic_inc_return(&trans_id);
1620
1621         cap_msg.caps.cap_bits.balloon = 1;
1622         cap_msg.caps.cap_bits.hot_add = 1;
1623
1624         /*
1625          * Specify our alignment requirements as it relates
1626          * memory hot-add. Specify 128MB alignment.
1627          */
1628         cap_msg.caps.cap_bits.hot_add_alignment = 7;
1629
1630         /*
1631          * Currently the host does not use these
1632          * values and we set them to what is done in the
1633          * Windows driver.
1634          */
1635         cap_msg.min_page_cnt = 0;
1636         cap_msg.max_page_number = -1;
1637
1638         ret = vmbus_sendpacket(dev->channel, &cap_msg,
1639                                 sizeof(struct dm_capabilities),
1640                                 (unsigned long)NULL,
1641                                 VM_PKT_DATA_INBAND, 0);
1642         if (ret)
1643                 goto probe_error2;
1644
1645         t = wait_for_completion_timeout(&dm_device.host_event, 5*HZ);
1646         if (t == 0) {
1647                 ret = -ETIMEDOUT;
1648                 goto probe_error2;
1649         }
1650
1651         /*
1652          * If the host does not like our capabilities,
1653          * fail the probe function.
1654          */
1655         if (dm_device.state == DM_INIT_ERROR) {
1656                 ret = -ETIMEDOUT;
1657                 goto probe_error2;
1658         }
1659
1660         dm_device.state = DM_INITIALIZED;
1661
1662         return 0;
1663
1664 probe_error2:
1665 #ifdef CONFIG_MEMORY_HOTPLUG
1666         restore_online_page_callback(&hv_online_page);
1667 #endif
1668         kthread_stop(dm_device.thread);
1669
1670 probe_error1:
1671         vmbus_close(dev->channel);
1672 probe_error0:
1673         kfree(send_buffer);
1674         return ret;
1675 }
1676
1677 static int balloon_remove(struct hv_device *dev)
1678 {
1679         struct hv_dynmem_device *dm = hv_get_drvdata(dev);
1680         struct hv_hotadd_state *has, *tmp;
1681         struct hv_hotadd_gap *gap, *tmp_gap;
1682         unsigned long flags;
1683
1684         if (dm->num_pages_ballooned != 0)
1685                 pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned);
1686
1687         cancel_work_sync(&dm->balloon_wrk.wrk);
1688         cancel_work_sync(&dm->ha_wrk.wrk);
1689
1690         vmbus_close(dev->channel);
1691         kthread_stop(dm->thread);
1692         kfree(send_buffer);
1693 #ifdef CONFIG_MEMORY_HOTPLUG
1694         restore_online_page_callback(&hv_online_page);
1695         unregister_memory_notifier(&hv_memory_nb);
1696 #endif
1697         spin_lock_irqsave(&dm_device.ha_lock, flags);
1698         list_for_each_entry_safe(has, tmp, &dm->ha_region_list, list) {
1699                 list_for_each_entry_safe(gap, tmp_gap, &has->gap_list, list) {
1700                         list_del(&gap->list);
1701                         kfree(gap);
1702                 }
1703                 list_del(&has->list);
1704                 kfree(has);
1705         }
1706         spin_unlock_irqrestore(&dm_device.ha_lock, flags);
1707
1708         return 0;
1709 }
1710
1711 static const struct hv_vmbus_device_id id_table[] = {
1712         /* Dynamic Memory Class ID */
1713         /* 525074DC-8985-46e2-8057-A307DC18A502 */
1714         { HV_DM_GUID, },
1715         { },
1716 };
1717
1718 MODULE_DEVICE_TABLE(vmbus, id_table);
1719
1720 static  struct hv_driver balloon_drv = {
1721         .name = "hv_balloon",
1722         .id_table = id_table,
1723         .probe =  balloon_probe,
1724         .remove =  balloon_remove,
1725 };
1726
1727 static int __init init_balloon_drv(void)
1728 {
1729
1730         return vmbus_driver_register(&balloon_drv);
1731 }
1732
1733 module_init(init_balloon_drv);
1734
1735 MODULE_DESCRIPTION("Hyper-V Balloon");
1736 MODULE_LICENSE("GPL");