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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (c) 2012, Microsoft Corporation.4 *5 * Author:6 * K. Y. Srinivasan <kys@microsoft.com>7 */8 9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt10 11#include <linux/cleanup.h>12#include <linux/kernel.h>13#include <linux/jiffies.h>14#include <linux/mman.h>15#include <linux/debugfs.h>16#include <linux/delay.h>17#include <linux/init.h>18#include <linux/module.h>19#include <linux/slab.h>20#include <linux/kthread.h>21#include <linux/completion.h>22#include <linux/count_zeros.h>23#include <linux/memory_hotplug.h>24#include <linux/memory.h>25#include <linux/notifier.h>26#include <linux/percpu_counter.h>27#include <linux/page_reporting.h>28#include <linux/sizes.h>29 30#include <linux/hyperv.h>31#include <asm/hyperv-tlfs.h>32 33#include <asm/mshyperv.h>34 35#define CREATE_TRACE_POINTS36#include "hv_trace_balloon.h"37 38/*39 * We begin with definitions supporting the Dynamic Memory protocol40 * with the host.41 *42 * Begin protocol definitions.43 */44 45/*46 * Protocol versions. The low word is the minor version, the high word the major47 * version.48 *49 * History:50 * Initial version 1.051 * Changed to 0.1 on 2009/03/2552 * Changes to 0.2 on 2009/05/1453 * Changes to 0.3 on 2009/12/0354 * Changed to 1.0 on 2011/04/0555 */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 DYNMEM_PROTOCOL_VERSION_3 = DYNMEM_MAKE_VERSION(2, 0),65 66 DYNMEM_PROTOCOL_VERSION_WIN7 = DYNMEM_PROTOCOL_VERSION_1,67 DYNMEM_PROTOCOL_VERSION_WIN8 = DYNMEM_PROTOCOL_VERSION_2,68 DYNMEM_PROTOCOL_VERSION_WIN10 = DYNMEM_PROTOCOL_VERSION_3,69 70 DYNMEM_PROTOCOL_VERSION_CURRENT = DYNMEM_PROTOCOL_VERSION_WIN1071};72 73/*74 * Message Types75 */76 77enum dm_message_type {78 /*79 * Version 0.380 */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 = 1299};100 101/*102 * Structures defining the dynamic memory management103 * protocol.104 */105 106union dm_version {107 struct {108 __u16 minor_version;109 __u16 major_version;110 };111 __u32 version;112} __packed;113 114union dm_caps {115 struct {116 __u64 balloon:1;117 __u64 hot_add:1;118 /*119 * To support guests that may have alignment120 * limitations on hot-add, the guest can specify121 * its alignment requirements; a value of n122 * represents an alignment of 2^n in mega bytes.123 */124 __u64 hot_add_alignment:4;125 __u64 reservedz:58;126 } cap_bits;127 __u64 caps;128} __packed;129 130union dm_mem_page_range {131 struct {132 /*133 * The PFN number of the first page in the range.134 * 40 bits is the architectural limit of a PFN135 * number for AMD64.136 */137 __u64 start_page:40;138 /*139 * The number of pages in the range.140 */141 __u64 page_cnt:24;142 } finfo;143 __u64 page_range;144} __packed;145 146/*147 * The header for all dynamic memory messages:148 *149 * type: Type of the message.150 * size: Size of the message in bytes; including the header.151 * trans_id: The guest is responsible for manufacturing this ID.152 */153 154struct dm_header {155 __u16 type;156 __u16 size;157 __u32 trans_id;158} __packed;159 160/*161 * A generic message format for dynamic memory.162 * Specific message formats are defined later in the file.163 */164 165struct dm_message {166 struct dm_header hdr;167 __u8 data[]; /* enclosed message */168} __packed;169 170/*171 * Specific message types supporting the dynamic memory protocol.172 */173 174/*175 * Version negotiation message. Sent from the guest to the host.176 * The guest is free to try different versions until the host177 * accepts the version.178 *179 * dm_version: The protocol version requested.180 * is_last_attempt: If TRUE, this is the last version guest will request.181 * reservedz: Reserved field, set to zero.182 */183 184struct dm_version_request {185 struct dm_header hdr;186 union dm_version version;187 __u32 is_last_attempt:1;188 __u32 reservedz:31;189} __packed;190 191/*192 * Version response message; Host to Guest and indicates193 * if the host has accepted the version sent by the guest.194 *195 * is_accepted: If TRUE, host has accepted the version and the guest196 * should proceed to the next stage of the protocol. FALSE indicates that197 * guest should re-try with a different version.198 *199 * reservedz: Reserved field, set to zero.200 */201 202struct dm_version_response {203 struct dm_header hdr;204 __u64 is_accepted:1;205 __u64 reservedz:63;206} __packed;207 208/*209 * Message reporting capabilities. This is sent from the guest to the210 * host.211 */212 213struct dm_capabilities {214 struct dm_header hdr;215 union dm_caps caps;216 __u64 min_page_cnt;217 __u64 max_page_number;218} __packed;219 220/*221 * Response to the capabilities message. This is sent from the host to the222 * guest. This message notifies if the host has accepted the guest's223 * capabilities. If the host has not accepted, the guest must shutdown224 * the service.225 *226 * is_accepted: Indicates if the host has accepted guest's capabilities.227 * reservedz: Must be 0.228 */229 230struct dm_capabilities_resp_msg {231 struct dm_header hdr;232 __u64 is_accepted:1;233 __u64 reservedz:63;234} __packed;235 236/*237 * This message is used to report memory pressure from the guest.238 * This message is not part of any transaction and there is no239 * response to this message.240 *241 * num_avail: Available memory in pages.242 * num_committed: Committed memory in pages.243 * page_file_size: The accumulated size of all page files244 * in the system in pages.245 * zero_free: The number of zero and free pages.246 * page_file_writes: The writes to the page file in pages.247 * io_diff: An indicator of file cache efficiency or page file activity,248 * calculated as File Cache Page Fault Count - Page Read Count.249 * This value is in pages.250 *251 * Some of these metrics are Windows specific and fortunately252 * the algorithm on the host side that computes the guest memory253 * pressure only uses num_committed value.254 */255 256struct dm_status {257 struct dm_header hdr;258 __u64 num_avail;259 __u64 num_committed;260 __u64 page_file_size;261 __u64 zero_free;262 __u32 page_file_writes;263 __u32 io_diff;264} __packed;265 266/*267 * Message to ask the guest to allocate memory - balloon up message.268 * This message is sent from the host to the guest. The guest may not be269 * able to allocate as much memory as requested.270 *271 * num_pages: number of pages to allocate.272 */273 274struct dm_balloon {275 struct dm_header hdr;276 __u32 num_pages;277 __u32 reservedz;278} __packed;279 280/*281 * Balloon response message; this message is sent from the guest282 * to the host in response to the balloon message.283 *284 * reservedz: Reserved; must be set to zero.285 * more_pages: If FALSE, this is the last message of the transaction.286 * if TRUE there will be at least one more message from the guest.287 *288 * range_count: The number of ranges in the range array.289 *290 * range_array: An array of page ranges returned to the host.291 *292 */293 294struct dm_balloon_response {295 struct dm_header hdr;296 __u32 reservedz;297 __u32 more_pages:1;298 __u32 range_count:31;299 union dm_mem_page_range range_array[];300} __packed;301 302/*303 * Un-balloon message; this message is sent from the host304 * to the guest to give guest more memory.305 *306 * more_pages: If FALSE, this is the last message of the transaction.307 * if TRUE there will be at least one more message from the guest.308 *309 * reservedz: Reserved; must be set to zero.310 *311 * range_count: The number of ranges in the range array.312 *313 * range_array: An array of page ranges returned to the host.314 *315 */316 317struct dm_unballoon_request {318 struct dm_header hdr;319 __u32 more_pages:1;320 __u32 reservedz:31;321 __u32 range_count;322 union dm_mem_page_range range_array[];323} __packed;324 325/*326 * Un-balloon response message; this message is sent from the guest327 * to the host in response to an unballoon request.328 *329 */330 331struct dm_unballoon_response {332 struct dm_header hdr;333} __packed;334 335/*336 * Hot add request message. Message sent from the host to the guest.337 *338 * mem_range: Memory range to hot add.339 *340 */341 342struct dm_hot_add {343 struct dm_header hdr;344 union dm_mem_page_range range;345} __packed;346 347/*348 * Hot add response message.349 * This message is sent by the guest to report the status of a hot add request.350 * If page_count is less than the requested page count, then the host should351 * assume all further hot add requests will fail, since this indicates that352 * the guest has hit an upper physical memory barrier.353 *354 * Hot adds may also fail due to low resources; in this case, the guest must355 * not complete this message until the hot add can succeed, and the host must356 * not send a new hot add request until the response is sent.357 * If VSC fails to hot add memory DYNMEM_NUMBER_OF_UNSUCCESSFUL_HOTADD_ATTEMPTS358 * times it fails the request.359 *360 *361 * page_count: number of pages that were successfully hot added.362 *363 * result: result of the operation 1: success, 0: failure.364 *365 */366 367struct dm_hot_add_response {368 struct dm_header hdr;369 __u32 page_count;370 __u32 result;371} __packed;372 373/*374 * Types of information sent from host to the guest.375 */376 377enum dm_info_type {378 INFO_TYPE_MAX_PAGE_CNT = 0,379 MAX_INFO_TYPE380};381 382/*383 * Header for the information message.384 */385 386struct dm_info_header {387 enum dm_info_type type;388 __u32 data_size;389} __packed;390 391/*392 * This message is sent from the host to the guest to pass393 * some relevant information (win8 addition).394 *395 * reserved: no used.396 * info_size: size of the information blob.397 * info: information blob.398 */399 400struct dm_info_msg {401 struct dm_header hdr;402 __u32 reserved;403 __u32 info_size;404 __u8 info[];405};406 407/*408 * End protocol definitions.409 */410 411/*412 * State to manage hot adding memory into the guest.413 * The range start_pfn : end_pfn specifies the range414 * that the host has asked us to hot add. The range415 * start_pfn : ha_end_pfn specifies the range that we have416 * currently hot added. We hot add in chunks equal to the417 * memory block size; it is possible that we may not be able418 * to bring online all the pages in the region. The range419 * covered_start_pfn:covered_end_pfn defines the pages that can420 * be brought online.421 */422 423struct hv_hotadd_state {424 struct list_head list;425 unsigned long start_pfn;426 unsigned long covered_start_pfn;427 unsigned long covered_end_pfn;428 unsigned long ha_end_pfn;429 unsigned long end_pfn;430 /*431 * A list of gaps.432 */433 struct list_head gap_list;434};435 436struct hv_hotadd_gap {437 struct list_head list;438 unsigned long start_pfn;439 unsigned long end_pfn;440};441 442struct balloon_state {443 __u32 num_pages;444 struct work_struct wrk;445};446 447struct hot_add_wrk {448 union dm_mem_page_range ha_page_range;449 union dm_mem_page_range ha_region_range;450 struct work_struct wrk;451};452 453static bool allow_hibernation;454static bool hot_add = true;455static bool do_hot_add;456/*457 * Delay reporting memory pressure by458 * the specified number of seconds.459 */460static uint pressure_report_delay = 45;461extern unsigned int page_reporting_order;462#define HV_MAX_FAILURES 2463 464/*465 * The last time we posted a pressure report to host.466 */467static unsigned long last_post_time;468 469static int hv_hypercall_multi_failure;470 471module_param(hot_add, bool, 0644);472MODULE_PARM_DESC(hot_add, "If set attempt memory hot_add");473 474module_param(pressure_report_delay, uint, 0644);475MODULE_PARM_DESC(pressure_report_delay, "Delay in secs in reporting pressure");476static atomic_t trans_id = ATOMIC_INIT(0);477 478static int dm_ring_size = VMBUS_RING_SIZE(16 * 1024);479 480/*481 * Driver specific state.482 */483 484enum hv_dm_state {485 DM_INITIALIZING = 0,486 DM_INITIALIZED,487 DM_BALLOON_UP,488 DM_BALLOON_DOWN,489 DM_HOT_ADD,490 DM_INIT_ERROR491};492 493static __u8 recv_buffer[HV_HYP_PAGE_SIZE];494static __u8 balloon_up_send_buffer[HV_HYP_PAGE_SIZE];495 496static unsigned long ha_pages_in_chunk;497#define HA_BYTES_IN_CHUNK (ha_pages_in_chunk << PAGE_SHIFT)498 499#define PAGES_IN_2M (2 * 1024 * 1024 / PAGE_SIZE)500 501struct hv_dynmem_device {502 struct hv_device *dev;503 enum hv_dm_state state;504 struct completion host_event;505 struct completion config_event;506 507 /*508 * Number of pages we have currently ballooned out.509 */510 unsigned int num_pages_ballooned;511 unsigned int num_pages_onlined;512 unsigned int num_pages_added;513 514 /*515 * State to manage the ballooning (up) operation.516 */517 struct balloon_state balloon_wrk;518 519 /*520 * State to execute the "hot-add" operation.521 */522 struct hot_add_wrk ha_wrk;523 524 /*525 * This state tracks if the host has specified a hot-add526 * region.527 */528 bool host_specified_ha_region;529 530 /*531 * State to synchronize hot-add.532 */533 struct completion ol_waitevent;534 /*535 * This thread handles hot-add536 * requests from the host as well as notifying537 * the host with regards to memory pressure in538 * the guest.539 */540 struct task_struct *thread;541 542 /*543 * Protects ha_region_list, num_pages_onlined counter and individual544 * regions from ha_region_list.545 */546 spinlock_t ha_lock;547 548 /*549 * A list of hot-add regions.550 */551 struct list_head ha_region_list;552 553 /*554 * We start with the highest version we can support555 * and downgrade based on the host; we save here the556 * next version to try.557 */558 __u32 next_version;559 560 /*561 * The negotiated version agreed by host.562 */563 __u32 version;564 565 struct page_reporting_dev_info pr_dev_info;566 567 /*568 * Maximum number of pages that can be hot_add-ed569 */570 __u64 max_dynamic_page_count;571};572 573static struct hv_dynmem_device dm_device;574 575static void post_status(struct hv_dynmem_device *dm);576 577static void enable_page_reporting(void);578 579static void disable_page_reporting(void);580 581#ifdef CONFIG_MEMORY_HOTPLUG582static inline bool has_pfn_is_backed(struct hv_hotadd_state *has,583 unsigned long pfn)584{585 struct hv_hotadd_gap *gap;586 587 /* The page is not backed. */588 if (pfn < has->covered_start_pfn || pfn >= has->covered_end_pfn)589 return false;590 591 /* Check for gaps. */592 list_for_each_entry(gap, &has->gap_list, list) {593 if (pfn >= gap->start_pfn && pfn < gap->end_pfn)594 return false;595 }596 597 return true;598}599 600static unsigned long hv_page_offline_check(unsigned long start_pfn,601 unsigned long nr_pages)602{603 unsigned long pfn = start_pfn, count = 0;604 struct hv_hotadd_state *has;605 bool found;606 607 while (pfn < start_pfn + nr_pages) {608 /*609 * Search for HAS which covers the pfn and when we find one610 * count how many consequitive PFNs are covered.611 */612 found = false;613 list_for_each_entry(has, &dm_device.ha_region_list, list) {614 while ((pfn >= has->start_pfn) &&615 (pfn < has->end_pfn) &&616 (pfn < start_pfn + nr_pages)) {617 found = true;618 if (has_pfn_is_backed(has, pfn))619 count++;620 pfn++;621 }622 }623 624 /*625 * This PFN is not in any HAS (e.g. we're offlining a region626 * which was present at boot), no need to account for it. Go627 * to the next one.628 */629 if (!found)630 pfn++;631 }632 633 return count;634}635 636static int hv_memory_notifier(struct notifier_block *nb, unsigned long val,637 void *v)638{639 struct memory_notify *mem = (struct memory_notify *)v;640 unsigned long pfn_count;641 642 switch (val) {643 case MEM_ONLINE:644 case MEM_CANCEL_ONLINE:645 complete(&dm_device.ol_waitevent);646 break;647 648 case MEM_OFFLINE:649 scoped_guard(spinlock_irqsave, &dm_device.ha_lock) {650 pfn_count = hv_page_offline_check(mem->start_pfn,651 mem->nr_pages);652 if (pfn_count <= dm_device.num_pages_onlined) {653 dm_device.num_pages_onlined -= pfn_count;654 } else {655 /*656 * We're offlining more pages than we657 * managed to online. This is658 * unexpected. In any case don't let659 * num_pages_onlined wrap around zero.660 */661 WARN_ON_ONCE(1);662 dm_device.num_pages_onlined = 0;663 }664 }665 break;666 case MEM_GOING_ONLINE:667 case MEM_GOING_OFFLINE:668 case MEM_CANCEL_OFFLINE:669 break;670 }671 return NOTIFY_OK;672}673 674static struct notifier_block hv_memory_nb = {675 .notifier_call = hv_memory_notifier,676 .priority = 0677};678 679/* Check if the particular page is backed and can be onlined and online it. */680static void hv_page_online_one(struct hv_hotadd_state *has, struct page *pg)681{682 if (!has_pfn_is_backed(has, page_to_pfn(pg))) {683 if (!PageOffline(pg))684 __SetPageOffline(pg);685 return;686 } else if (!PageOffline(pg))687 return;688 689 /* This frame is currently backed; online the page. */690 generic_online_page(pg, 0);691 692 lockdep_assert_held(&dm_device.ha_lock);693 dm_device.num_pages_onlined++;694}695 696static void hv_bring_pgs_online(struct hv_hotadd_state *has,697 unsigned long start_pfn, unsigned long size)698{699 int i;700 701 pr_debug("Online %lu pages starting at pfn 0x%lx\n", size, start_pfn);702 for (i = 0; i < size; i++)703 hv_page_online_one(has, pfn_to_page(start_pfn + i));704}705 706static void hv_mem_hot_add(unsigned long start, unsigned long size,707 unsigned long pfn_count,708 struct hv_hotadd_state *has)709{710 int ret = 0;711 int i, nid;712 unsigned long start_pfn;713 unsigned long processed_pfn;714 unsigned long total_pfn = pfn_count;715 716 for (i = 0; i < (size/ha_pages_in_chunk); i++) {717 start_pfn = start + (i * ha_pages_in_chunk);718 719 scoped_guard(spinlock_irqsave, &dm_device.ha_lock) {720 has->ha_end_pfn += ha_pages_in_chunk;721 processed_pfn = umin(total_pfn, ha_pages_in_chunk);722 total_pfn -= processed_pfn;723 has->covered_end_pfn += processed_pfn;724 }725 726 reinit_completion(&dm_device.ol_waitevent);727 728 nid = memory_add_physaddr_to_nid(PFN_PHYS(start_pfn));729 ret = add_memory(nid, PFN_PHYS((start_pfn)),730 HA_BYTES_IN_CHUNK, MHP_MERGE_RESOURCE);731 732 if (ret) {733 pr_err("hot_add memory failed error is %d\n", ret);734 if (ret == -EEXIST) {735 /*736 * This error indicates that the error737 * is not a transient failure. This is the738 * case where the guest's physical address map739 * precludes hot adding memory. Stop all further740 * memory hot-add.741 */742 do_hot_add = false;743 }744 scoped_guard(spinlock_irqsave, &dm_device.ha_lock) {745 has->ha_end_pfn -= ha_pages_in_chunk;746 has->covered_end_pfn -= processed_pfn;747 }748 break;749 }750 751 /*752 * Wait for memory to get onlined. If the kernel onlined the753 * memory when adding it, this will return directly. Otherwise,754 * it will wait for user space to online the memory. This helps755 * to avoid adding memory faster than it is getting onlined. As756 * adding succeeded, it is ok to proceed even if the memory was757 * not onlined in time.758 */759 wait_for_completion_timeout(&dm_device.ol_waitevent, 5 * HZ);760 post_status(&dm_device);761 }762}763 764static void hv_online_page(struct page *pg, unsigned int order)765{766 struct hv_hotadd_state *has;767 unsigned long pfn = page_to_pfn(pg);768 769 guard(spinlock_irqsave)(&dm_device.ha_lock);770 list_for_each_entry(has, &dm_device.ha_region_list, list) {771 /* The page belongs to a different HAS. */772 if (pfn < has->start_pfn ||773 (pfn + (1UL << order) > has->end_pfn))774 continue;775 776 hv_bring_pgs_online(has, pfn, 1UL << order);777 break;778 }779}780 781static int pfn_covered(unsigned long start_pfn, unsigned long pfn_cnt)782{783 struct hv_hotadd_state *has;784 struct hv_hotadd_gap *gap;785 unsigned long residual;786 int ret = 0;787 788 guard(spinlock_irqsave)(&dm_device.ha_lock);789 list_for_each_entry(has, &dm_device.ha_region_list, list) {790 /*791 * If the pfn range we are dealing with is not in the current792 * "hot add block", move on.793 */794 if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn)795 continue;796 797 /*798 * If the current start pfn is not where the covered_end799 * is, create a gap and update covered_end_pfn.800 */801 if (has->covered_end_pfn != start_pfn) {802 gap = kzalloc(sizeof(struct hv_hotadd_gap), GFP_ATOMIC);803 if (!gap) {804 ret = -ENOMEM;805 break;806 }807 808 INIT_LIST_HEAD(&gap->list);809 gap->start_pfn = has->covered_end_pfn;810 gap->end_pfn = start_pfn;811 list_add_tail(&gap->list, &has->gap_list);812 813 has->covered_end_pfn = start_pfn;814 }815 816 /*817 * If the current hot add-request extends beyond818 * our current limit; extend it.819 */820 if ((start_pfn + pfn_cnt) > has->end_pfn) {821 /* Extend the region by multiples of ha_pages_in_chunk */822 residual = (start_pfn + pfn_cnt - has->end_pfn);823 has->end_pfn += ALIGN(residual, ha_pages_in_chunk);824 }825 826 ret = 1;827 break;828 }829 830 return ret;831}832 833static unsigned long handle_pg_range(unsigned long pg_start,834 unsigned long pg_count)835{836 unsigned long start_pfn = pg_start;837 unsigned long pfn_cnt = pg_count;838 unsigned long size;839 struct hv_hotadd_state *has;840 unsigned long pgs_ol = 0;841 unsigned long old_covered_state;842 unsigned long res = 0, flags;843 844 pr_debug("Hot adding %lu pages starting at pfn 0x%lx.\n", pg_count,845 pg_start);846 847 spin_lock_irqsave(&dm_device.ha_lock, flags);848 list_for_each_entry(has, &dm_device.ha_region_list, list) {849 /*850 * If the pfn range we are dealing with is not in the current851 * "hot add block", move on.852 */853 if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn)854 continue;855 856 old_covered_state = has->covered_end_pfn;857 858 if (start_pfn < has->ha_end_pfn) {859 /*860 * This is the case where we are backing pages861 * in an already hot added region. Bring862 * these pages online first.863 */864 pgs_ol = has->ha_end_pfn - start_pfn;865 if (pgs_ol > pfn_cnt)866 pgs_ol = pfn_cnt;867 868 has->covered_end_pfn += pgs_ol;869 pfn_cnt -= pgs_ol;870 /*871 * Check if the corresponding memory block is already872 * online. It is possible to observe struct pages still873 * being uninitialized here so check section instead.874 * In case the section is online we need to bring the875 * rest of pfns (which were not backed previously)876 * online too.877 */878 if (start_pfn > has->start_pfn &&879 online_section_nr(pfn_to_section_nr(start_pfn)))880 hv_bring_pgs_online(has, start_pfn, pgs_ol);881 }882 883 if (has->ha_end_pfn < has->end_pfn && pfn_cnt > 0) {884 /*885 * We have some residual hot add range886 * that needs to be hot added; hot add887 * it now. Hot add a multiple of888 * ha_pages_in_chunk that fully covers the pages889 * we have.890 */891 size = (has->end_pfn - has->ha_end_pfn);892 if (pfn_cnt <= size) {893 size = ALIGN(pfn_cnt, ha_pages_in_chunk);894 } else {895 pfn_cnt = size;896 }897 spin_unlock_irqrestore(&dm_device.ha_lock, flags);898 hv_mem_hot_add(has->ha_end_pfn, size, pfn_cnt, has);899 spin_lock_irqsave(&dm_device.ha_lock, flags);900 }901 /*902 * If we managed to online any pages that were given to us,903 * we declare success.904 */905 res = has->covered_end_pfn - old_covered_state;906 break;907 }908 spin_unlock_irqrestore(&dm_device.ha_lock, flags);909 910 return res;911}912 913static unsigned long process_hot_add(unsigned long pg_start,914 unsigned long pfn_cnt,915 unsigned long rg_start,916 unsigned long rg_size)917{918 struct hv_hotadd_state *ha_region = NULL;919 int covered;920 921 if (pfn_cnt == 0)922 return 0;923 924 if (!dm_device.host_specified_ha_region) {925 covered = pfn_covered(pg_start, pfn_cnt);926 if (covered < 0)927 return 0;928 929 if (covered)930 goto do_pg_range;931 }932 933 /*934 * If the host has specified a hot-add range; deal with it first.935 */936 937 if (rg_size != 0) {938 ha_region = kzalloc(sizeof(struct hv_hotadd_state), GFP_KERNEL);939 if (!ha_region)940 return 0;941 942 INIT_LIST_HEAD(&ha_region->list);943 INIT_LIST_HEAD(&ha_region->gap_list);944 945 ha_region->start_pfn = rg_start;946 ha_region->ha_end_pfn = rg_start;947 ha_region->covered_start_pfn = pg_start;948 ha_region->covered_end_pfn = pg_start;949 ha_region->end_pfn = rg_start + rg_size;950 951 scoped_guard(spinlock_irqsave, &dm_device.ha_lock) {952 list_add_tail(&ha_region->list, &dm_device.ha_region_list);953 }954 }955 956do_pg_range:957 /*958 * Process the page range specified; bringing them959 * online if possible.960 */961 return handle_pg_range(pg_start, pfn_cnt);962}963 964#endif965 966static void hot_add_req(struct work_struct *dummy)967{968 struct dm_hot_add_response resp;969#ifdef CONFIG_MEMORY_HOTPLUG970 unsigned long pg_start, pfn_cnt;971 unsigned long rg_start, rg_sz;972#endif973 struct hv_dynmem_device *dm = &dm_device;974 975 memset(&resp, 0, sizeof(struct dm_hot_add_response));976 resp.hdr.type = DM_MEM_HOT_ADD_RESPONSE;977 resp.hdr.size = sizeof(struct dm_hot_add_response);978 979#ifdef CONFIG_MEMORY_HOTPLUG980 pg_start = dm->ha_wrk.ha_page_range.finfo.start_page;981 pfn_cnt = dm->ha_wrk.ha_page_range.finfo.page_cnt;982 983 rg_start = dm->ha_wrk.ha_region_range.finfo.start_page;984 rg_sz = dm->ha_wrk.ha_region_range.finfo.page_cnt;985 986 if (rg_start == 0 && !dm->host_specified_ha_region) {987 /*988 * The host has not specified the hot-add region.989 * Based on the hot-add page range being specified,990 * compute a hot-add region that can cover the pages991 * that need to be hot-added while ensuring the alignment992 * and size requirements of Linux as it relates to hot-add.993 */994 rg_start = ALIGN_DOWN(pg_start, ha_pages_in_chunk);995 rg_sz = ALIGN(pfn_cnt, ha_pages_in_chunk);996 }997 998 if (do_hot_add)999 resp.page_count = process_hot_add(pg_start, pfn_cnt,1000 rg_start, rg_sz);1001 1002 dm->num_pages_added += resp.page_count;1003#endif1004 /*1005 * The result field of the response structure has the1006 * following semantics:1007 *1008 * 1. If all or some pages hot-added: Guest should return success.1009 *1010 * 2. If no pages could be hot-added:1011 *1012 * If the guest returns success, then the host1013 * will not attempt any further hot-add operations. This1014 * signifies a permanent failure.1015 *1016 * If the guest returns failure, then this failure will be1017 * treated as a transient failure and the host may retry the1018 * hot-add operation after some delay.1019 */1020 if (resp.page_count > 0)1021 resp.result = 1;1022 else if (!do_hot_add)1023 resp.result = 1;1024 else1025 resp.result = 0;1026 1027 if (!do_hot_add || resp.page_count == 0) {1028 if (!allow_hibernation)1029 pr_err("Memory hot add failed\n");1030 else1031 pr_info("Ignore hot-add request!\n");1032 }1033 1034 dm->state = DM_INITIALIZED;1035 resp.hdr.trans_id = atomic_inc_return(&trans_id);1036 vmbus_sendpacket(dm->dev->channel, &resp,1037 sizeof(struct dm_hot_add_response),1038 (unsigned long)NULL,1039 VM_PKT_DATA_INBAND, 0);1040}1041 1042static void process_info(struct hv_dynmem_device *dm, struct dm_info_msg *msg)1043{1044 struct dm_info_header *info_hdr;1045 1046 info_hdr = (struct dm_info_header *)msg->info;1047 1048 switch (info_hdr->type) {1049 case INFO_TYPE_MAX_PAGE_CNT:1050 if (info_hdr->data_size == sizeof(__u64)) {1051 __u64 *max_page_count = (__u64 *)&info_hdr[1];1052 1053 pr_info("Max. dynamic memory size: %llu MB\n",1054 (*max_page_count) >> (20 - HV_HYP_PAGE_SHIFT));1055 dm->max_dynamic_page_count = *max_page_count;1056 }1057 1058 break;1059 default:1060 pr_warn("Received Unknown type: %d\n", info_hdr->type);1061 }1062}1063 1064static unsigned long compute_balloon_floor(void)1065{1066 unsigned long min_pages;1067 unsigned long nr_pages = totalram_pages();1068#define MB2PAGES(mb) ((mb) << (20 - PAGE_SHIFT))1069 /* Simple continuous piecewiese linear function:1070 * max MiB -> min MiB gradient1071 * 0 01072 * 16 161073 * 32 241074 * 128 72 (1/2)1075 * 512 168 (1/4)1076 * 2048 360 (1/8)1077 * 8192 744 (1/16)1078 * 32768 1512 (1/32)1079 */1080 if (nr_pages < MB2PAGES(128))1081 min_pages = MB2PAGES(8) + (nr_pages >> 1);1082 else if (nr_pages < MB2PAGES(512))1083 min_pages = MB2PAGES(40) + (nr_pages >> 2);1084 else if (nr_pages < MB2PAGES(2048))1085 min_pages = MB2PAGES(104) + (nr_pages >> 3);1086 else if (nr_pages < MB2PAGES(8192))1087 min_pages = MB2PAGES(232) + (nr_pages >> 4);1088 else1089 min_pages = MB2PAGES(488) + (nr_pages >> 5);1090#undef MB2PAGES1091 return min_pages;1092}1093 1094/*1095 * Compute total committed memory pages1096 */1097 1098static unsigned long get_pages_committed(struct hv_dynmem_device *dm)1099{1100 return vm_memory_committed() +1101 dm->num_pages_ballooned +1102 (dm->num_pages_added > dm->num_pages_onlined ?1103 dm->num_pages_added - dm->num_pages_onlined : 0) +1104 compute_balloon_floor();1105}1106 1107/*1108 * Post our status as it relates memory pressure to the1109 * host. Host expects the guests to post this status1110 * periodically at 1 second intervals.1111 *1112 * The metrics specified in this protocol are very Windows1113 * specific and so we cook up numbers here to convey our memory1114 * pressure.1115 */1116 1117static void post_status(struct hv_dynmem_device *dm)1118{1119 struct dm_status status;1120 unsigned long now = jiffies;1121 unsigned long last_post = last_post_time;1122 unsigned long num_pages_avail, num_pages_committed;1123 1124 if (pressure_report_delay > 0) {1125 --pressure_report_delay;1126 return;1127 }1128 1129 if (!time_after(now, (last_post_time + HZ)))1130 return;1131 1132 memset(&status, 0, sizeof(struct dm_status));1133 status.hdr.type = DM_STATUS_REPORT;1134 status.hdr.size = sizeof(struct dm_status);1135 status.hdr.trans_id = atomic_inc_return(&trans_id);1136 1137 /*1138 * The host expects the guest to report free and committed memory.1139 * Furthermore, the host expects the pressure information to include1140 * the ballooned out pages. For a given amount of memory that we are1141 * managing we need to compute a floor below which we should not1142 * balloon. Compute this and add it to the pressure report.1143 * We also need to report all offline pages (num_pages_added -1144 * num_pages_onlined) as committed to the host, otherwise it can try1145 * asking us to balloon them out.1146 */1147 num_pages_avail = si_mem_available();1148 num_pages_committed = get_pages_committed(dm);1149 1150 trace_balloon_status(num_pages_avail, num_pages_committed,1151 vm_memory_committed(), dm->num_pages_ballooned,1152 dm->num_pages_added, dm->num_pages_onlined);1153 1154 /* Convert numbers of pages into numbers of HV_HYP_PAGEs. */1155 status.num_avail = num_pages_avail * NR_HV_HYP_PAGES_IN_PAGE;1156 status.num_committed = num_pages_committed * NR_HV_HYP_PAGES_IN_PAGE;1157 1158 /*1159 * If our transaction ID is no longer current, just don't1160 * send the status. This can happen if we were interrupted1161 * after we picked our transaction ID.1162 */1163 if (status.hdr.trans_id != atomic_read(&trans_id))1164 return;1165 1166 /*1167 * If the last post time that we sampled has changed,1168 * we have raced, don't post the status.1169 */1170 if (last_post != last_post_time)1171 return;1172 1173 last_post_time = jiffies;1174 vmbus_sendpacket(dm->dev->channel, &status,1175 sizeof(struct dm_status),1176 (unsigned long)NULL,1177 VM_PKT_DATA_INBAND, 0);1178}1179 1180static void free_balloon_pages(struct hv_dynmem_device *dm,1181 union dm_mem_page_range *range_array)1182{1183 int num_pages = range_array->finfo.page_cnt;1184 __u64 start_frame = range_array->finfo.start_page;1185 struct page *pg;1186 int i;1187 1188 for (i = 0; i < num_pages; i++) {1189 pg = pfn_to_page(i + start_frame);1190 __ClearPageOffline(pg);1191 __free_page(pg);1192 dm->num_pages_ballooned--;1193 adjust_managed_page_count(pg, 1);1194 }1195}1196 1197static unsigned int alloc_balloon_pages(struct hv_dynmem_device *dm,1198 unsigned int num_pages,1199 struct dm_balloon_response *bl_resp,1200 int alloc_unit)1201{1202 unsigned int i, j;1203 struct page *pg;1204 1205 for (i = 0; i < num_pages / alloc_unit; i++) {1206 if (bl_resp->hdr.size + sizeof(union dm_mem_page_range) >1207 HV_HYP_PAGE_SIZE)1208 return i * alloc_unit;1209 1210 /*1211 * We execute this code in a thread context. Furthermore,1212 * we don't want the kernel to try too hard.1213 */1214 pg = alloc_pages(GFP_HIGHUSER | __GFP_NORETRY |1215 __GFP_NOMEMALLOC | __GFP_NOWARN,1216 get_order(alloc_unit << PAGE_SHIFT));1217 1218 if (!pg)1219 return i * alloc_unit;1220 1221 dm->num_pages_ballooned += alloc_unit;1222 1223 /*1224 * If we allocatted 2M pages; split them so we1225 * can free them in any order we get.1226 */1227 1228 if (alloc_unit != 1)1229 split_page(pg, get_order(alloc_unit << PAGE_SHIFT));1230 1231 /* mark all pages offline */1232 for (j = 0; j < alloc_unit; j++) {1233 __SetPageOffline(pg + j);1234 adjust_managed_page_count(pg + j, -1);1235 }1236 1237 bl_resp->range_count++;1238 bl_resp->range_array[i].finfo.start_page =1239 page_to_pfn(pg);1240 bl_resp->range_array[i].finfo.page_cnt = alloc_unit;1241 bl_resp->hdr.size += sizeof(union dm_mem_page_range);1242 }1243 1244 return i * alloc_unit;1245}1246 1247static void balloon_up(struct work_struct *dummy)1248{1249 unsigned int num_pages = dm_device.balloon_wrk.num_pages;1250 unsigned int num_ballooned = 0;1251 struct dm_balloon_response *bl_resp;1252 int alloc_unit;1253 int ret;1254 bool done = false;1255 int i;1256 long avail_pages;1257 unsigned long floor;1258 1259 /*1260 * We will attempt 2M allocations. However, if we fail to1261 * allocate 2M chunks, we will go back to PAGE_SIZE allocations.1262 */1263 alloc_unit = PAGES_IN_2M;1264 1265 avail_pages = si_mem_available();1266 floor = compute_balloon_floor();1267 1268 /* Refuse to balloon below the floor. */1269 if (avail_pages < num_pages || avail_pages - num_pages < floor) {1270 pr_info("Balloon request will be partially fulfilled. %s\n",1271 avail_pages < num_pages ? "Not enough memory." :1272 "Balloon floor reached.");1273 1274 num_pages = avail_pages > floor ? (avail_pages - floor) : 0;1275 }1276 1277 while (!done) {1278 memset(balloon_up_send_buffer, 0, HV_HYP_PAGE_SIZE);1279 bl_resp = (struct dm_balloon_response *)balloon_up_send_buffer;1280 bl_resp->hdr.type = DM_BALLOON_RESPONSE;1281 bl_resp->hdr.size = sizeof(struct dm_balloon_response);1282 bl_resp->more_pages = 1;1283 1284 num_pages -= num_ballooned;1285 num_ballooned = alloc_balloon_pages(&dm_device, num_pages,1286 bl_resp, alloc_unit);1287 1288 if (alloc_unit != 1 && num_ballooned == 0) {1289 alloc_unit = 1;1290 continue;1291 }1292 1293 if (num_ballooned == 0 || num_ballooned == num_pages) {1294 pr_debug("Ballooned %u out of %u requested pages.\n",1295 num_pages, dm_device.balloon_wrk.num_pages);1296 1297 bl_resp->more_pages = 0;1298 done = true;1299 dm_device.state = DM_INITIALIZED;1300 }1301 1302 /*1303 * We are pushing a lot of data through the channel;1304 * deal with transient failures caused because of the1305 * lack of space in the ring buffer.1306 */1307 1308 do {1309 bl_resp->hdr.trans_id = atomic_inc_return(&trans_id);1310 ret = vmbus_sendpacket(dm_device.dev->channel,1311 bl_resp,1312 bl_resp->hdr.size,1313 (unsigned long)NULL,1314 VM_PKT_DATA_INBAND, 0);1315 1316 if (ret == -EAGAIN)1317 msleep(20);1318 post_status(&dm_device);1319 } while (ret == -EAGAIN);1320 1321 if (ret) {1322 /*1323 * Free up the memory we allocatted.1324 */1325 pr_err("Balloon response failed\n");1326 1327 for (i = 0; i < bl_resp->range_count; i++)1328 free_balloon_pages(&dm_device,1329 &bl_resp->range_array[i]);1330 1331 done = true;1332 }1333 }1334}1335 1336static void balloon_down(struct hv_dynmem_device *dm,1337 struct dm_unballoon_request *req)1338{1339 union dm_mem_page_range *range_array = req->range_array;1340 int range_count = req->range_count;1341 struct dm_unballoon_response resp;1342 int i;1343 unsigned int prev_pages_ballooned = dm->num_pages_ballooned;1344 1345 for (i = 0; i < range_count; i++) {1346 free_balloon_pages(dm, &range_array[i]);1347 complete(&dm_device.config_event);1348 }1349 1350 pr_debug("Freed %u ballooned pages.\n",1351 prev_pages_ballooned - dm->num_pages_ballooned);1352 1353 if (req->more_pages == 1)1354 return;1355 1356 memset(&resp, 0, sizeof(struct dm_unballoon_response));1357 resp.hdr.type = DM_UNBALLOON_RESPONSE;1358 resp.hdr.trans_id = atomic_inc_return(&trans_id);1359 resp.hdr.size = sizeof(struct dm_unballoon_response);1360 1361 vmbus_sendpacket(dm_device.dev->channel, &resp,1362 sizeof(struct dm_unballoon_response),1363 (unsigned long)NULL,1364 VM_PKT_DATA_INBAND, 0);1365 1366 dm->state = DM_INITIALIZED;1367}1368 1369static void balloon_onchannelcallback(void *context);1370 1371static int dm_thread_func(void *dm_dev)1372{1373 struct hv_dynmem_device *dm = dm_dev;1374 1375 while (!kthread_should_stop()) {1376 wait_for_completion_interruptible_timeout(&dm_device.config_event, 1 * HZ);1377 /*1378 * The host expects us to post information on the memory1379 * pressure every second.1380 */1381 reinit_completion(&dm_device.config_event);1382 post_status(dm);1383 /*1384 * disable free page reporting if multiple hypercall1385 * failure flag set. It is not done in the page_reporting1386 * callback context as that causes a deadlock between1387 * page_reporting_process() and page_reporting_unregister()1388 */1389 if (hv_hypercall_multi_failure >= HV_MAX_FAILURES) {1390 pr_err("Multiple failures in cold memory discard hypercall, disabling page reporting\n");1391 disable_page_reporting();1392 /* Reset the flag after disabling reporting */1393 hv_hypercall_multi_failure = 0;1394 }1395 }1396 1397 return 0;1398}1399 1400static void version_resp(struct hv_dynmem_device *dm,1401 struct dm_version_response *vresp)1402{1403 struct dm_version_request version_req;1404 int ret;1405 1406 if (vresp->is_accepted) {1407 /*1408 * We are done; wakeup the1409 * context waiting for version1410 * negotiation.1411 */1412 complete(&dm->host_event);1413 return;1414 }1415 /*1416 * If there are more versions to try, continue1417 * with negotiations; if not1418 * shutdown the service since we are not able1419 * to negotiate a suitable version number1420 * with the host.1421 */1422 if (dm->next_version == 0)1423 goto version_error;1424 1425 memset(&version_req, 0, sizeof(struct dm_version_request));1426 version_req.hdr.type = DM_VERSION_REQUEST;1427 version_req.hdr.size = sizeof(struct dm_version_request);1428 version_req.hdr.trans_id = atomic_inc_return(&trans_id);1429 version_req.version.version = dm->next_version;1430 dm->version = version_req.version.version;1431 1432 /*1433 * Set the next version to try in case current version fails.1434 * Win7 protocol ought to be the last one to try.1435 */1436 switch (version_req.version.version) {1437 case DYNMEM_PROTOCOL_VERSION_WIN8:1438 dm->next_version = DYNMEM_PROTOCOL_VERSION_WIN7;1439 version_req.is_last_attempt = 0;1440 break;1441 default:1442 dm->next_version = 0;1443 version_req.is_last_attempt = 1;1444 }1445 1446 ret = vmbus_sendpacket(dm->dev->channel, &version_req,1447 sizeof(struct dm_version_request),1448 (unsigned long)NULL,1449 VM_PKT_DATA_INBAND, 0);1450 1451 if (ret)1452 goto version_error;1453 1454 return;1455 1456version_error:1457 dm->state = DM_INIT_ERROR;1458 complete(&dm->host_event);1459}1460 1461static void cap_resp(struct hv_dynmem_device *dm,1462 struct dm_capabilities_resp_msg *cap_resp)1463{1464 if (!cap_resp->is_accepted) {1465 pr_err("Capabilities not accepted by host\n");1466 dm->state = DM_INIT_ERROR;1467 }1468 complete(&dm->host_event);1469}1470 1471static void balloon_onchannelcallback(void *context)1472{1473 struct hv_device *dev = context;1474 u32 recvlen;1475 u64 requestid;1476 struct dm_message *dm_msg;1477 struct dm_header *dm_hdr;1478 struct hv_dynmem_device *dm = hv_get_drvdata(dev);1479 struct dm_balloon *bal_msg;1480 struct dm_hot_add *ha_msg;1481 union dm_mem_page_range *ha_pg_range;1482 union dm_mem_page_range *ha_region;1483 1484 memset(recv_buffer, 0, sizeof(recv_buffer));1485 vmbus_recvpacket(dev->channel, recv_buffer,1486 HV_HYP_PAGE_SIZE, &recvlen, &requestid);1487 1488 if (recvlen > 0) {1489 dm_msg = (struct dm_message *)recv_buffer;1490 dm_hdr = &dm_msg->hdr;1491 1492 switch (dm_hdr->type) {1493 case DM_VERSION_RESPONSE:1494 version_resp(dm,1495 (struct dm_version_response *)dm_msg);1496 break;1497 1498 case DM_CAPABILITIES_RESPONSE:1499 cap_resp(dm,1500 (struct dm_capabilities_resp_msg *)dm_msg);1501 break;1502 1503 case DM_BALLOON_REQUEST:1504 if (allow_hibernation) {1505 pr_info("Ignore balloon-up request!\n");1506 break;1507 }1508 1509 if (dm->state == DM_BALLOON_UP)1510 pr_warn("Currently ballooning\n");1511 bal_msg = (struct dm_balloon *)recv_buffer;1512 dm->state = DM_BALLOON_UP;1513 dm_device.balloon_wrk.num_pages = bal_msg->num_pages;1514 schedule_work(&dm_device.balloon_wrk.wrk);1515 break;1516 1517 case DM_UNBALLOON_REQUEST:1518 if (allow_hibernation) {1519 pr_info("Ignore balloon-down request!\n");1520 break;1521 }1522 1523 dm->state = DM_BALLOON_DOWN;1524 balloon_down(dm,1525 (struct dm_unballoon_request *)recv_buffer);1526 break;1527 1528 case DM_MEM_HOT_ADD_REQUEST:1529 if (dm->state == DM_HOT_ADD)1530 pr_warn("Currently hot-adding\n");1531 dm->state = DM_HOT_ADD;1532 ha_msg = (struct dm_hot_add *)recv_buffer;1533 if (ha_msg->hdr.size == sizeof(struct dm_hot_add)) {1534 /*1535 * This is a normal hot-add request specifying1536 * hot-add memory.1537 */1538 dm->host_specified_ha_region = false;1539 ha_pg_range = &ha_msg->range;1540 dm->ha_wrk.ha_page_range = *ha_pg_range;1541 dm->ha_wrk.ha_region_range.page_range = 0;1542 } else {1543 /*1544 * Host is specifying that we first hot-add1545 * a region and then partially populate this1546 * region.1547 */1548 dm->host_specified_ha_region = true;1549 ha_pg_range = &ha_msg->range;1550 ha_region = &ha_pg_range[1];1551 dm->ha_wrk.ha_page_range = *ha_pg_range;1552 dm->ha_wrk.ha_region_range = *ha_region;1553 }1554 schedule_work(&dm_device.ha_wrk.wrk);1555 break;1556 1557 case DM_INFO_MESSAGE:1558 process_info(dm, (struct dm_info_msg *)dm_msg);1559 break;1560 1561 default:1562 pr_warn_ratelimited("Unhandled message: type: %d\n", dm_hdr->type);1563 }1564 }1565}1566 1567#define HV_LARGE_REPORTING_ORDER 91568#define HV_LARGE_REPORTING_LEN (HV_HYP_PAGE_SIZE << \1569 HV_LARGE_REPORTING_ORDER)1570static int hv_free_page_report(struct page_reporting_dev_info *pr_dev_info,1571 struct scatterlist *sgl, unsigned int nents)1572{1573 unsigned long flags;1574 struct hv_memory_hint *hint;1575 int i, order;1576 u64 status;1577 struct scatterlist *sg;1578 1579 WARN_ON_ONCE(nents > HV_MEMORY_HINT_MAX_GPA_PAGE_RANGES);1580 WARN_ON_ONCE(sgl->length < (HV_HYP_PAGE_SIZE << page_reporting_order));1581 local_irq_save(flags);1582 hint = *this_cpu_ptr(hyperv_pcpu_input_arg);1583 if (!hint) {1584 local_irq_restore(flags);1585 return -ENOSPC;1586 }1587 1588 hint->type = HV_EXT_MEMORY_HEAT_HINT_TYPE_COLD_DISCARD;1589 hint->reserved = 0;1590 for_each_sg(sgl, sg, nents, i) {1591 union hv_gpa_page_range *range;1592 1593 range = &hint->ranges[i];1594 range->address_space = 0;1595 order = get_order(sg->length);1596 /*1597 * Hyper-V expects the additional_pages field in the units1598 * of one of these 3 sizes, 4Kbytes, 2Mbytes or 1Gbytes.1599 * This is dictated by the values of the fields page.largesize1600 * and page_size.1601 * This code however, only uses 4Kbytes and 2Mbytes units1602 * and not 1Gbytes unit.1603 */1604 1605 /* page reporting for pages 2MB or higher */1606 if (order >= HV_LARGE_REPORTING_ORDER) {1607 range->page.largepage = 1;1608 range->page_size = HV_GPA_PAGE_RANGE_PAGE_SIZE_2MB;1609 range->base_large_pfn = page_to_hvpfn(1610 sg_page(sg)) >> HV_LARGE_REPORTING_ORDER;1611 range->page.additional_pages =1612 (sg->length / HV_LARGE_REPORTING_LEN) - 1;1613 } else {1614 /* Page reporting for pages below 2MB */1615 range->page.basepfn = page_to_hvpfn(sg_page(sg));1616 range->page.largepage = false;1617 range->page.additional_pages =1618 (sg->length / HV_HYP_PAGE_SIZE) - 1;1619 }1620 }1621 1622 status = hv_do_rep_hypercall(HV_EXT_CALL_MEMORY_HEAT_HINT, nents, 0,1623 hint, NULL);1624 local_irq_restore(flags);1625 if (!hv_result_success(status)) {1626 pr_err("Cold memory discard hypercall failed with status %llx\n",1627 status);1628 if (hv_hypercall_multi_failure > 0)1629 hv_hypercall_multi_failure++;1630 1631 if (hv_result(status) == HV_STATUS_INVALID_PARAMETER) {1632 pr_err("Underlying Hyper-V does not support order less than 9. Hypercall failed\n");1633 pr_err("Defaulting to page_reporting_order %d\n",1634 pageblock_order);1635 page_reporting_order = pageblock_order;1636 hv_hypercall_multi_failure++;1637 return -EINVAL;1638 }1639 1640 return -EINVAL;1641 }1642 1643 return 0;1644}1645 1646static void enable_page_reporting(void)1647{1648 int ret;1649 1650 if (!hv_query_ext_cap(HV_EXT_CAPABILITY_MEMORY_COLD_DISCARD_HINT)) {1651 pr_debug("Cold memory discard hint not supported by Hyper-V\n");1652 return;1653 }1654 1655 BUILD_BUG_ON(PAGE_REPORTING_CAPACITY > HV_MEMORY_HINT_MAX_GPA_PAGE_RANGES);1656 dm_device.pr_dev_info.report = hv_free_page_report;1657 /*1658 * We let the page_reporting_order parameter decide the order1659 * in the page_reporting code1660 */1661 dm_device.pr_dev_info.order = 0;1662 ret = page_reporting_register(&dm_device.pr_dev_info);1663 if (ret < 0) {1664 dm_device.pr_dev_info.report = NULL;1665 pr_err("Failed to enable cold memory discard: %d\n", ret);1666 } else {1667 pr_info("Cold memory discard hint enabled with order %d\n",1668 page_reporting_order);1669 }1670}1671 1672static void disable_page_reporting(void)1673{1674 if (dm_device.pr_dev_info.report) {1675 page_reporting_unregister(&dm_device.pr_dev_info);1676 dm_device.pr_dev_info.report = NULL;1677 }1678}1679 1680static int ballooning_enabled(void)1681{1682 /*1683 * Disable ballooning if the page size is not 4k (HV_HYP_PAGE_SIZE),1684 * since currently it's unclear to us whether an unballoon request can1685 * make sure all page ranges are guest page size aligned.1686 */1687 if (PAGE_SIZE != HV_HYP_PAGE_SIZE) {1688 pr_info("Ballooning disabled because page size is not 4096 bytes\n");1689 return 0;1690 }1691 1692 return 1;1693}1694 1695static int hot_add_enabled(void)1696{1697 /*1698 * Disable hot add on ARM64, because we currently rely on1699 * memory_add_physaddr_to_nid() to get a node id of a hot add range,1700 * however ARM64's memory_add_physaddr_to_nid() always return 0 and1701 * DM_MEM_HOT_ADD_REQUEST doesn't have the NUMA node information for1702 * add_memory().1703 */1704 if (IS_ENABLED(CONFIG_ARM64)) {1705 pr_info("Memory hot add disabled on ARM64\n");1706 return 0;1707 }1708 1709 return 1;1710}1711 1712static int balloon_connect_vsp(struct hv_device *dev)1713{1714 struct dm_version_request version_req;1715 struct dm_capabilities cap_msg;1716 unsigned long t;1717 int ret;1718 1719 /*1720 * max_pkt_size should be large enough for one vmbus packet header plus1721 * our receive buffer size. Hyper-V sends messages up to1722 * HV_HYP_PAGE_SIZE bytes long on balloon channel.1723 */1724 dev->channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2;1725 1726 ret = vmbus_open(dev->channel, dm_ring_size, dm_ring_size, NULL, 0,1727 balloon_onchannelcallback, dev);1728 if (ret)1729 return ret;1730 1731 /*1732 * Initiate the hand shake with the host and negotiate1733 * a version that the host can support. We start with the1734 * highest version number and go down if the host cannot1735 * support it.1736 */1737 memset(&version_req, 0, sizeof(struct dm_version_request));1738 version_req.hdr.type = DM_VERSION_REQUEST;1739 version_req.hdr.size = sizeof(struct dm_version_request);1740 version_req.hdr.trans_id = atomic_inc_return(&trans_id);1741 version_req.version.version = DYNMEM_PROTOCOL_VERSION_WIN10;1742 version_req.is_last_attempt = 0;1743 dm_device.version = version_req.version.version;1744 1745 ret = vmbus_sendpacket(dev->channel, &version_req,1746 sizeof(struct dm_version_request),1747 (unsigned long)NULL, VM_PKT_DATA_INBAND, 0);1748 if (ret)1749 goto out;1750 1751 t = wait_for_completion_timeout(&dm_device.host_event, 5 * HZ);1752 if (t == 0) {1753 ret = -ETIMEDOUT;1754 goto out;1755 }1756 1757 /*1758 * If we could not negotiate a compatible version with the host1759 * fail the probe function.1760 */1761 if (dm_device.state == DM_INIT_ERROR) {1762 ret = -EPROTO;1763 goto out;1764 }1765 1766 pr_info("Using Dynamic Memory protocol version %u.%u\n",1767 DYNMEM_MAJOR_VERSION(dm_device.version),1768 DYNMEM_MINOR_VERSION(dm_device.version));1769 1770 /*1771 * Now submit our capabilities to the host.1772 */1773 memset(&cap_msg, 0, sizeof(struct dm_capabilities));1774 cap_msg.hdr.type = DM_CAPABILITIES_REPORT;1775 cap_msg.hdr.size = sizeof(struct dm_capabilities);1776 cap_msg.hdr.trans_id = atomic_inc_return(&trans_id);1777 1778 /*1779 * When hibernation (i.e. virtual ACPI S4 state) is enabled, the host1780 * currently still requires the bits to be set, so we have to add code1781 * to fail the host's hot-add and balloon up/down requests, if any.1782 */1783 cap_msg.caps.cap_bits.balloon = ballooning_enabled();1784 cap_msg.caps.cap_bits.hot_add = hot_add_enabled();1785 1786 /*1787 * Specify our alignment requirements for memory hot-add. The value is1788 * the log base 2 of the number of megabytes in a chunk. For example,1789 * with 256 MiB chunks, the value is 8. The number of MiB in a chunk1790 * must be a power of 2.1791 */1792 cap_msg.caps.cap_bits.hot_add_alignment =1793 ilog2(HA_BYTES_IN_CHUNK / SZ_1M);1794 1795 /*1796 * Currently the host does not use these1797 * values and we set them to what is done in the1798 * Windows driver.1799 */1800 cap_msg.min_page_cnt = 0;1801 cap_msg.max_page_number = -1;1802 1803 ret = vmbus_sendpacket(dev->channel, &cap_msg,1804 sizeof(struct dm_capabilities),1805 (unsigned long)NULL, VM_PKT_DATA_INBAND, 0);1806 if (ret)1807 goto out;1808 1809 t = wait_for_completion_timeout(&dm_device.host_event, 5 * HZ);1810 if (t == 0) {1811 ret = -ETIMEDOUT;1812 goto out;1813 }1814 1815 /*1816 * If the host does not like our capabilities,1817 * fail the probe function.1818 */1819 if (dm_device.state == DM_INIT_ERROR) {1820 ret = -EPROTO;1821 goto out;1822 }1823 1824 return 0;1825out:1826 vmbus_close(dev->channel);1827 return ret;1828}1829 1830/*1831 * DEBUGFS Interface1832 */1833#ifdef CONFIG_DEBUG_FS1834 1835/**1836 * hv_balloon_debug_show - shows statistics of balloon operations.1837 * @f: pointer to the &struct seq_file.1838 * @offset: ignored.1839 *1840 * Provides the statistics that can be accessed in hv-balloon in the debugfs.1841 *1842 * Return: zero on success or an error code.1843 */1844static int hv_balloon_debug_show(struct seq_file *f, void *offset)1845{1846 struct hv_dynmem_device *dm = f->private;1847 char *sname;1848 1849 seq_printf(f, "%-22s: %u.%u\n", "host_version",1850 DYNMEM_MAJOR_VERSION(dm->version),1851 DYNMEM_MINOR_VERSION(dm->version));1852 1853 seq_printf(f, "%-22s:", "capabilities");1854 if (ballooning_enabled())1855 seq_puts(f, " enabled");1856 1857 if (hot_add_enabled())1858 seq_puts(f, " hot_add");1859 1860 seq_puts(f, "\n");1861 1862 seq_printf(f, "%-22s: %u", "state", dm->state);1863 switch (dm->state) {1864 case DM_INITIALIZING:1865 sname = "Initializing";1866 break;1867 case DM_INITIALIZED:1868 sname = "Initialized";1869 break;1870 case DM_BALLOON_UP:1871 sname = "Balloon Up";1872 break;1873 case DM_BALLOON_DOWN:1874 sname = "Balloon Down";1875 break;1876 case DM_HOT_ADD:1877 sname = "Hot Add";1878 break;1879 case DM_INIT_ERROR:1880 sname = "Error";1881 break;1882 default:1883 sname = "Unknown";1884 }1885 seq_printf(f, " (%s)\n", sname);1886 1887 /* HV Page Size */1888 seq_printf(f, "%-22s: %ld\n", "page_size", HV_HYP_PAGE_SIZE);1889 1890 /* Pages added with hot_add */1891 seq_printf(f, "%-22s: %u\n", "pages_added", dm->num_pages_added);1892 1893 /* pages that are "onlined"/used from pages_added */1894 seq_printf(f, "%-22s: %u\n", "pages_onlined", dm->num_pages_onlined);1895 1896 /* pages we have given back to host */1897 seq_printf(f, "%-22s: %u\n", "pages_ballooned", dm->num_pages_ballooned);1898 1899 seq_printf(f, "%-22s: %lu\n", "total_pages_committed",1900 get_pages_committed(dm));1901 1902 seq_printf(f, "%-22s: %llu\n", "max_dynamic_page_count",1903 dm->max_dynamic_page_count);1904 1905 return 0;1906}1907 1908DEFINE_SHOW_ATTRIBUTE(hv_balloon_debug);1909 1910static void hv_balloon_debugfs_init(struct hv_dynmem_device *b)1911{1912 debugfs_create_file("hv-balloon", 0444, NULL, b,1913 &hv_balloon_debug_fops);1914}1915 1916static void hv_balloon_debugfs_exit(struct hv_dynmem_device *b)1917{1918 debugfs_lookup_and_remove("hv-balloon", NULL);1919}1920 1921#else1922 1923static inline void hv_balloon_debugfs_init(struct hv_dynmem_device *b)1924{1925}1926 1927static inline void hv_balloon_debugfs_exit(struct hv_dynmem_device *b)1928{1929}1930 1931#endif /* CONFIG_DEBUG_FS */1932 1933static int balloon_probe(struct hv_device *dev,1934 const struct hv_vmbus_device_id *dev_id)1935{1936 int ret;1937 1938 allow_hibernation = hv_is_hibernation_supported();1939 if (allow_hibernation)1940 hot_add = false;1941 1942#ifdef CONFIG_MEMORY_HOTPLUG1943 /*1944 * Hot-add must operate in chunks that are of size equal to the1945 * memory block size because that's what the core add_memory()1946 * interface requires. The Hyper-V interface requires that the memory1947 * block size be a power of 2, which is guaranteed by the check in1948 * memory_dev_init().1949 */1950 ha_pages_in_chunk = memory_block_size_bytes() / PAGE_SIZE;1951 do_hot_add = hot_add;1952#else1953 /*1954 * Without MEMORY_HOTPLUG, the guest returns a failure status for all1955 * hot add requests from Hyper-V, and the chunk size is used only to1956 * specify alignment to Hyper-V as required by the host/guest protocol.1957 * Somewhat arbitrarily, use 128 MiB.1958 */1959 ha_pages_in_chunk = SZ_128M / PAGE_SIZE;1960 do_hot_add = false;1961#endif1962 dm_device.dev = dev;1963 dm_device.state = DM_INITIALIZING;1964 dm_device.next_version = DYNMEM_PROTOCOL_VERSION_WIN8;1965 init_completion(&dm_device.host_event);1966 init_completion(&dm_device.config_event);1967 INIT_LIST_HEAD(&dm_device.ha_region_list);1968 spin_lock_init(&dm_device.ha_lock);1969 INIT_WORK(&dm_device.balloon_wrk.wrk, balloon_up);1970 INIT_WORK(&dm_device.ha_wrk.wrk, hot_add_req);1971 dm_device.host_specified_ha_region = false;1972 1973#ifdef CONFIG_MEMORY_HOTPLUG1974 set_online_page_callback(&hv_online_page);1975 init_completion(&dm_device.ol_waitevent);1976 register_memory_notifier(&hv_memory_nb);1977#endif1978 1979 hv_set_drvdata(dev, &dm_device);1980 1981 ret = balloon_connect_vsp(dev);1982 if (ret != 0)1983 goto connect_error;1984 1985 enable_page_reporting();1986 dm_device.state = DM_INITIALIZED;1987 1988 dm_device.thread =1989 kthread_run(dm_thread_func, &dm_device, "hv_balloon");1990 if (IS_ERR(dm_device.thread)) {1991 ret = PTR_ERR(dm_device.thread);1992 goto probe_error;1993 }1994 1995 hv_balloon_debugfs_init(&dm_device);1996 1997 return 0;1998 1999probe_error:2000 dm_device.state = DM_INIT_ERROR;2001 dm_device.thread = NULL;2002 disable_page_reporting();2003 vmbus_close(dev->channel);2004connect_error:2005#ifdef CONFIG_MEMORY_HOTPLUG2006 unregister_memory_notifier(&hv_memory_nb);2007 restore_online_page_callback(&hv_online_page);2008#endif2009 return ret;2010}2011 2012static void balloon_remove(struct hv_device *dev)2013{2014 struct hv_dynmem_device *dm = hv_get_drvdata(dev);2015 struct hv_hotadd_state *has, *tmp;2016 struct hv_hotadd_gap *gap, *tmp_gap;2017 2018 if (dm->num_pages_ballooned != 0)2019 pr_warn("Ballooned pages: %d\n", dm->num_pages_ballooned);2020 2021 hv_balloon_debugfs_exit(dm);2022 2023 cancel_work_sync(&dm->balloon_wrk.wrk);2024 cancel_work_sync(&dm->ha_wrk.wrk);2025 2026 kthread_stop(dm->thread);2027 2028 /*2029 * This is to handle the case when balloon_resume()2030 * call has failed and some cleanup has been done as2031 * a part of the error handling.2032 */2033 if (dm_device.state != DM_INIT_ERROR) {2034 disable_page_reporting();2035 vmbus_close(dev->channel);2036#ifdef CONFIG_MEMORY_HOTPLUG2037 unregister_memory_notifier(&hv_memory_nb);2038 restore_online_page_callback(&hv_online_page);2039#endif2040 }2041 2042 guard(spinlock_irqsave)(&dm_device.ha_lock);2043 list_for_each_entry_safe(has, tmp, &dm->ha_region_list, list) {2044 list_for_each_entry_safe(gap, tmp_gap, &has->gap_list, list) {2045 list_del(&gap->list);2046 kfree(gap);2047 }2048 list_del(&has->list);2049 kfree(has);2050 }2051}2052 2053static int balloon_suspend(struct hv_device *hv_dev)2054{2055 struct hv_dynmem_device *dm = hv_get_drvdata(hv_dev);2056 2057 tasklet_disable(&hv_dev->channel->callback_event);2058 2059 cancel_work_sync(&dm->balloon_wrk.wrk);2060 cancel_work_sync(&dm->ha_wrk.wrk);2061 2062 if (dm->thread) {2063 kthread_stop(dm->thread);2064 dm->thread = NULL;2065 vmbus_close(hv_dev->channel);2066 }2067 2068 tasklet_enable(&hv_dev->channel->callback_event);2069 2070 return 0;2071}2072 2073static int balloon_resume(struct hv_device *dev)2074{2075 int ret;2076 2077 dm_device.state = DM_INITIALIZING;2078 2079 ret = balloon_connect_vsp(dev);2080 2081 if (ret != 0)2082 goto out;2083 2084 dm_device.thread =2085 kthread_run(dm_thread_func, &dm_device, "hv_balloon");2086 if (IS_ERR(dm_device.thread)) {2087 ret = PTR_ERR(dm_device.thread);2088 dm_device.thread = NULL;2089 goto close_channel;2090 }2091 2092 dm_device.state = DM_INITIALIZED;2093 return 0;2094close_channel:2095 vmbus_close(dev->channel);2096out:2097 dm_device.state = DM_INIT_ERROR;2098 disable_page_reporting();2099#ifdef CONFIG_MEMORY_HOTPLUG2100 unregister_memory_notifier(&hv_memory_nb);2101 restore_online_page_callback(&hv_online_page);2102#endif2103 return ret;2104}2105 2106static const struct hv_vmbus_device_id id_table[] = {2107 /* Dynamic Memory Class ID */2108 /* 525074DC-8985-46e2-8057-A307DC18A502 */2109 { HV_DM_GUID, },2110 { },2111};2112 2113MODULE_DEVICE_TABLE(vmbus, id_table);2114 2115static struct hv_driver balloon_drv = {2116 .name = "hv_balloon",2117 .id_table = id_table,2118 .probe = balloon_probe,2119 .remove = balloon_remove,2120 .suspend = balloon_suspend,2121 .resume = balloon_resume,2122 .driver = {2123 .probe_type = PROBE_PREFER_ASYNCHRONOUS,2124 },2125};2126 2127static int __init init_balloon_drv(void)2128{2129 return vmbus_driver_register(&balloon_drv);2130}2131 2132module_init(init_balloon_drv);2133 2134MODULE_DESCRIPTION("Hyper-V Balloon");2135MODULE_LICENSE("GPL");2136