linux/drivers/hv/channel_mgmt.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (c) 2009, Microsoft Corporation.
   4 *
   5 * Authors:
   6 *   Haiyang Zhang <haiyangz@microsoft.com>
   7 *   Hank Janssen  <hjanssen@microsoft.com>
   8 */
   9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11#include <linux/kernel.h>
  12#include <linux/interrupt.h>
  13#include <linux/sched.h>
  14#include <linux/wait.h>
  15#include <linux/mm.h>
  16#include <linux/slab.h>
  17#include <linux/list.h>
  18#include <linux/module.h>
  19#include <linux/completion.h>
  20#include <linux/delay.h>
  21#include <linux/hyperv.h>
  22#include <asm/mshyperv.h>
  23
  24#include "hyperv_vmbus.h"
  25
  26static void init_vp_index(struct vmbus_channel *channel, u16 dev_type);
  27
  28static const struct vmbus_device vmbus_devs[] = {
  29        /* IDE */
  30        { .dev_type = HV_IDE,
  31          HV_IDE_GUID,
  32          .perf_device = true,
  33        },
  34
  35        /* SCSI */
  36        { .dev_type = HV_SCSI,
  37          HV_SCSI_GUID,
  38          .perf_device = true,
  39        },
  40
  41        /* Fibre Channel */
  42        { .dev_type = HV_FC,
  43          HV_SYNTHFC_GUID,
  44          .perf_device = true,
  45        },
  46
  47        /* Synthetic NIC */
  48        { .dev_type = HV_NIC,
  49          HV_NIC_GUID,
  50          .perf_device = true,
  51        },
  52
  53        /* Network Direct */
  54        { .dev_type = HV_ND,
  55          HV_ND_GUID,
  56          .perf_device = true,
  57        },
  58
  59        /* PCIE */
  60        { .dev_type = HV_PCIE,
  61          HV_PCIE_GUID,
  62          .perf_device = false,
  63        },
  64
  65        /* Synthetic Frame Buffer */
  66        { .dev_type = HV_FB,
  67          HV_SYNTHVID_GUID,
  68          .perf_device = false,
  69        },
  70
  71        /* Synthetic Keyboard */
  72        { .dev_type = HV_KBD,
  73          HV_KBD_GUID,
  74          .perf_device = false,
  75        },
  76
  77        /* Synthetic MOUSE */
  78        { .dev_type = HV_MOUSE,
  79          HV_MOUSE_GUID,
  80          .perf_device = false,
  81        },
  82
  83        /* KVP */
  84        { .dev_type = HV_KVP,
  85          HV_KVP_GUID,
  86          .perf_device = false,
  87        },
  88
  89        /* Time Synch */
  90        { .dev_type = HV_TS,
  91          HV_TS_GUID,
  92          .perf_device = false,
  93        },
  94
  95        /* Heartbeat */
  96        { .dev_type = HV_HB,
  97          HV_HEART_BEAT_GUID,
  98          .perf_device = false,
  99        },
 100
 101        /* Shutdown */
 102        { .dev_type = HV_SHUTDOWN,
 103          HV_SHUTDOWN_GUID,
 104          .perf_device = false,
 105        },
 106
 107        /* File copy */
 108        { .dev_type = HV_FCOPY,
 109          HV_FCOPY_GUID,
 110          .perf_device = false,
 111        },
 112
 113        /* Backup */
 114        { .dev_type = HV_BACKUP,
 115          HV_VSS_GUID,
 116          .perf_device = false,
 117        },
 118
 119        /* Dynamic Memory */
 120        { .dev_type = HV_DM,
 121          HV_DM_GUID,
 122          .perf_device = false,
 123        },
 124
 125        /* Unknown GUID */
 126        { .dev_type = HV_UNKNOWN,
 127          .perf_device = false,
 128        },
 129};
 130
 131static const struct {
 132        guid_t guid;
 133} vmbus_unsupported_devs[] = {
 134        { HV_AVMA1_GUID },
 135        { HV_AVMA2_GUID },
 136        { HV_RDV_GUID   },
 137};
 138
 139/*
 140 * The rescinded channel may be blocked waiting for a response from the host;
 141 * take care of that.
 142 */
 143static void vmbus_rescind_cleanup(struct vmbus_channel *channel)
 144{
 145        struct vmbus_channel_msginfo *msginfo;
 146        unsigned long flags;
 147
 148
 149        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 150        channel->rescind = true;
 151        list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 152                                msglistentry) {
 153
 154                if (msginfo->waiting_channel == channel) {
 155                        complete(&msginfo->waitevent);
 156                        break;
 157                }
 158        }
 159        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 160}
 161
 162static bool is_unsupported_vmbus_devs(const guid_t *guid)
 163{
 164        int i;
 165
 166        for (i = 0; i < ARRAY_SIZE(vmbus_unsupported_devs); i++)
 167                if (guid_equal(guid, &vmbus_unsupported_devs[i].guid))
 168                        return true;
 169        return false;
 170}
 171
 172static u16 hv_get_dev_type(const struct vmbus_channel *channel)
 173{
 174        const guid_t *guid = &channel->offermsg.offer.if_type;
 175        u16 i;
 176
 177        if (is_hvsock_channel(channel) || is_unsupported_vmbus_devs(guid))
 178                return HV_UNKNOWN;
 179
 180        for (i = HV_IDE; i < HV_UNKNOWN; i++) {
 181                if (guid_equal(guid, &vmbus_devs[i].guid))
 182                        return i;
 183        }
 184        pr_info("Unknown GUID: %pUl\n", guid);
 185        return i;
 186}
 187
 188/**
 189 * vmbus_prep_negotiate_resp() - Create default response for Negotiate message
 190 * @icmsghdrp: Pointer to msg header structure
 191 * @buf: Raw buffer channel data
 192 * @fw_version: The framework versions we can support.
 193 * @fw_vercnt: The size of @fw_version.
 194 * @srv_version: The service versions we can support.
 195 * @srv_vercnt: The size of @srv_version.
 196 * @nego_fw_version: The selected framework version.
 197 * @nego_srv_version: The selected service version.
 198 *
 199 * Note: Versions are given in decreasing order.
 200 *
 201 * Set up and fill in default negotiate response message.
 202 * Mainly used by Hyper-V drivers.
 203 */
 204bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
 205                                u8 *buf, const int *fw_version, int fw_vercnt,
 206                                const int *srv_version, int srv_vercnt,
 207                                int *nego_fw_version, int *nego_srv_version)
 208{
 209        int icframe_major, icframe_minor;
 210        int icmsg_major, icmsg_minor;
 211        int fw_major, fw_minor;
 212        int srv_major, srv_minor;
 213        int i, j;
 214        bool found_match = false;
 215        struct icmsg_negotiate *negop;
 216
 217        icmsghdrp->icmsgsize = 0x10;
 218        negop = (struct icmsg_negotiate *)&buf[
 219                sizeof(struct vmbuspipe_hdr) +
 220                sizeof(struct icmsg_hdr)];
 221
 222        icframe_major = negop->icframe_vercnt;
 223        icframe_minor = 0;
 224
 225        icmsg_major = negop->icmsg_vercnt;
 226        icmsg_minor = 0;
 227
 228        /*
 229         * Select the framework version number we will
 230         * support.
 231         */
 232
 233        for (i = 0; i < fw_vercnt; i++) {
 234                fw_major = (fw_version[i] >> 16);
 235                fw_minor = (fw_version[i] & 0xFFFF);
 236
 237                for (j = 0; j < negop->icframe_vercnt; j++) {
 238                        if ((negop->icversion_data[j].major == fw_major) &&
 239                            (negop->icversion_data[j].minor == fw_minor)) {
 240                                icframe_major = negop->icversion_data[j].major;
 241                                icframe_minor = negop->icversion_data[j].minor;
 242                                found_match = true;
 243                                break;
 244                        }
 245                }
 246
 247                if (found_match)
 248                        break;
 249        }
 250
 251        if (!found_match)
 252                goto fw_error;
 253
 254        found_match = false;
 255
 256        for (i = 0; i < srv_vercnt; i++) {
 257                srv_major = (srv_version[i] >> 16);
 258                srv_minor = (srv_version[i] & 0xFFFF);
 259
 260                for (j = negop->icframe_vercnt;
 261                        (j < negop->icframe_vercnt + negop->icmsg_vercnt);
 262                        j++) {
 263
 264                        if ((negop->icversion_data[j].major == srv_major) &&
 265                                (negop->icversion_data[j].minor == srv_minor)) {
 266
 267                                icmsg_major = negop->icversion_data[j].major;
 268                                icmsg_minor = negop->icversion_data[j].minor;
 269                                found_match = true;
 270                                break;
 271                        }
 272                }
 273
 274                if (found_match)
 275                        break;
 276        }
 277
 278        /*
 279         * Respond with the framework and service
 280         * version numbers we can support.
 281         */
 282
 283fw_error:
 284        if (!found_match) {
 285                negop->icframe_vercnt = 0;
 286                negop->icmsg_vercnt = 0;
 287        } else {
 288                negop->icframe_vercnt = 1;
 289                negop->icmsg_vercnt = 1;
 290        }
 291
 292        if (nego_fw_version)
 293                *nego_fw_version = (icframe_major << 16) | icframe_minor;
 294
 295        if (nego_srv_version)
 296                *nego_srv_version = (icmsg_major << 16) | icmsg_minor;
 297
 298        negop->icversion_data[0].major = icframe_major;
 299        negop->icversion_data[0].minor = icframe_minor;
 300        negop->icversion_data[1].major = icmsg_major;
 301        negop->icversion_data[1].minor = icmsg_minor;
 302        return found_match;
 303}
 304
 305EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);
 306
 307/*
 308 * alloc_channel - Allocate and initialize a vmbus channel object
 309 */
 310static struct vmbus_channel *alloc_channel(void)
 311{
 312        struct vmbus_channel *channel;
 313
 314        channel = kzalloc(sizeof(*channel), GFP_ATOMIC);
 315        if (!channel)
 316                return NULL;
 317
 318        spin_lock_init(&channel->lock);
 319        init_completion(&channel->rescind_event);
 320
 321        INIT_LIST_HEAD(&channel->sc_list);
 322        INIT_LIST_HEAD(&channel->percpu_list);
 323
 324        tasklet_init(&channel->callback_event,
 325                     vmbus_on_event, (unsigned long)channel);
 326
 327        hv_ringbuffer_pre_init(channel);
 328
 329        return channel;
 330}
 331
 332/*
 333 * free_channel - Release the resources used by the vmbus channel object
 334 */
 335static void free_channel(struct vmbus_channel *channel)
 336{
 337        tasklet_kill(&channel->callback_event);
 338        vmbus_remove_channel_attr_group(channel);
 339
 340        kobject_put(&channel->kobj);
 341}
 342
 343static void percpu_channel_enq(void *arg)
 344{
 345        struct vmbus_channel *channel = arg;
 346        struct hv_per_cpu_context *hv_cpu
 347                = this_cpu_ptr(hv_context.cpu_context);
 348
 349        list_add_tail_rcu(&channel->percpu_list, &hv_cpu->chan_list);
 350}
 351
 352static void percpu_channel_deq(void *arg)
 353{
 354        struct vmbus_channel *channel = arg;
 355
 356        list_del_rcu(&channel->percpu_list);
 357}
 358
 359
 360static void vmbus_release_relid(u32 relid)
 361{
 362        struct vmbus_channel_relid_released msg;
 363        int ret;
 364
 365        memset(&msg, 0, sizeof(struct vmbus_channel_relid_released));
 366        msg.child_relid = relid;
 367        msg.header.msgtype = CHANNELMSG_RELID_RELEASED;
 368        ret = vmbus_post_msg(&msg, sizeof(struct vmbus_channel_relid_released),
 369                             true);
 370
 371        trace_vmbus_release_relid(&msg, ret);
 372}
 373
 374void hv_process_channel_removal(struct vmbus_channel *channel)
 375{
 376        struct vmbus_channel *primary_channel;
 377        unsigned long flags;
 378
 379        BUG_ON(!mutex_is_locked(&vmbus_connection.channel_mutex));
 380        BUG_ON(!channel->rescind);
 381
 382        if (channel->target_cpu != get_cpu()) {
 383                put_cpu();
 384                smp_call_function_single(channel->target_cpu,
 385                                         percpu_channel_deq, channel, true);
 386        } else {
 387                percpu_channel_deq(channel);
 388                put_cpu();
 389        }
 390
 391        if (channel->primary_channel == NULL) {
 392                list_del(&channel->listentry);
 393
 394                primary_channel = channel;
 395        } else {
 396                primary_channel = channel->primary_channel;
 397                spin_lock_irqsave(&primary_channel->lock, flags);
 398                list_del(&channel->sc_list);
 399                spin_unlock_irqrestore(&primary_channel->lock, flags);
 400        }
 401
 402        /*
 403         * We need to free the bit for init_vp_index() to work in the case
 404         * of sub-channel, when we reload drivers like hv_netvsc.
 405         */
 406        if (channel->affinity_policy == HV_LOCALIZED)
 407                cpumask_clear_cpu(channel->target_cpu,
 408                                  &primary_channel->alloced_cpus_in_node);
 409
 410        /*
 411         * Upon suspend, an in-use hv_sock channel is marked as "rescinded" and
 412         * the relid is invalidated; after hibernation, when the user-space app
 413         * destroys the channel, the relid is INVALID_RELID, and in this case
 414         * it's unnecessary and unsafe to release the old relid, since the same
 415         * relid can refer to a completely different channel now.
 416         */
 417        if (channel->offermsg.child_relid != INVALID_RELID)
 418                vmbus_release_relid(channel->offermsg.child_relid);
 419
 420        free_channel(channel);
 421}
 422
 423void vmbus_free_channels(void)
 424{
 425        struct vmbus_channel *channel, *tmp;
 426
 427        list_for_each_entry_safe(channel, tmp, &vmbus_connection.chn_list,
 428                listentry) {
 429                /* hv_process_channel_removal() needs this */
 430                channel->rescind = true;
 431
 432                vmbus_device_unregister(channel->device_obj);
 433        }
 434}
 435
 436/* Note: the function can run concurrently for primary/sub channels. */
 437static void vmbus_add_channel_work(struct work_struct *work)
 438{
 439        struct vmbus_channel *newchannel =
 440                container_of(work, struct vmbus_channel, add_channel_work);
 441        struct vmbus_channel *primary_channel = newchannel->primary_channel;
 442        unsigned long flags;
 443        u16 dev_type;
 444        int ret;
 445
 446        dev_type = hv_get_dev_type(newchannel);
 447
 448        init_vp_index(newchannel, dev_type);
 449
 450        if (newchannel->target_cpu != get_cpu()) {
 451                put_cpu();
 452                smp_call_function_single(newchannel->target_cpu,
 453                                         percpu_channel_enq,
 454                                         newchannel, true);
 455        } else {
 456                percpu_channel_enq(newchannel);
 457                put_cpu();
 458        }
 459
 460        /*
 461         * This state is used to indicate a successful open
 462         * so that when we do close the channel normally, we
 463         * can cleanup properly.
 464         */
 465        newchannel->state = CHANNEL_OPEN_STATE;
 466
 467        if (primary_channel != NULL) {
 468                /* newchannel is a sub-channel. */
 469                struct hv_device *dev = primary_channel->device_obj;
 470
 471                if (vmbus_add_channel_kobj(dev, newchannel))
 472                        goto err_deq_chan;
 473
 474                if (primary_channel->sc_creation_callback != NULL)
 475                        primary_channel->sc_creation_callback(newchannel);
 476
 477                newchannel->probe_done = true;
 478                return;
 479        }
 480
 481        /*
 482         * Start the process of binding the primary channel to the driver
 483         */
 484        newchannel->device_obj = vmbus_device_create(
 485                &newchannel->offermsg.offer.if_type,
 486                &newchannel->offermsg.offer.if_instance,
 487                newchannel);
 488        if (!newchannel->device_obj)
 489                goto err_deq_chan;
 490
 491        newchannel->device_obj->device_id = dev_type;
 492        /*
 493         * Add the new device to the bus. This will kick off device-driver
 494         * binding which eventually invokes the device driver's AddDevice()
 495         * method.
 496         */
 497        ret = vmbus_device_register(newchannel->device_obj);
 498
 499        if (ret != 0) {
 500                pr_err("unable to add child device object (relid %d)\n",
 501                        newchannel->offermsg.child_relid);
 502                kfree(newchannel->device_obj);
 503                goto err_deq_chan;
 504        }
 505
 506        newchannel->probe_done = true;
 507        return;
 508
 509err_deq_chan:
 510        mutex_lock(&vmbus_connection.channel_mutex);
 511
 512        /*
 513         * We need to set the flag, otherwise
 514         * vmbus_onoffer_rescind() can be blocked.
 515         */
 516        newchannel->probe_done = true;
 517
 518        if (primary_channel == NULL) {
 519                list_del(&newchannel->listentry);
 520        } else {
 521                spin_lock_irqsave(&primary_channel->lock, flags);
 522                list_del(&newchannel->sc_list);
 523                spin_unlock_irqrestore(&primary_channel->lock, flags);
 524        }
 525
 526        mutex_unlock(&vmbus_connection.channel_mutex);
 527
 528        if (newchannel->target_cpu != get_cpu()) {
 529                put_cpu();
 530                smp_call_function_single(newchannel->target_cpu,
 531                                         percpu_channel_deq,
 532                                         newchannel, true);
 533        } else {
 534                percpu_channel_deq(newchannel);
 535                put_cpu();
 536        }
 537
 538        vmbus_release_relid(newchannel->offermsg.child_relid);
 539
 540        free_channel(newchannel);
 541}
 542
 543/*
 544 * vmbus_process_offer - Process the offer by creating a channel/device
 545 * associated with this offer
 546 */
 547static void vmbus_process_offer(struct vmbus_channel *newchannel)
 548{
 549        struct vmbus_channel *channel;
 550        struct workqueue_struct *wq;
 551        unsigned long flags;
 552        bool fnew = true;
 553
 554        mutex_lock(&vmbus_connection.channel_mutex);
 555
 556        /* Remember the channels that should be cleaned up upon suspend. */
 557        if (is_hvsock_channel(newchannel) || is_sub_channel(newchannel))
 558                atomic_inc(&vmbus_connection.nr_chan_close_on_suspend);
 559
 560        /*
 561         * Now that we have acquired the channel_mutex,
 562         * we can release the potentially racing rescind thread.
 563         */
 564        atomic_dec(&vmbus_connection.offer_in_progress);
 565
 566        list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 567                if (guid_equal(&channel->offermsg.offer.if_type,
 568                               &newchannel->offermsg.offer.if_type) &&
 569                    guid_equal(&channel->offermsg.offer.if_instance,
 570                               &newchannel->offermsg.offer.if_instance)) {
 571                        fnew = false;
 572                        break;
 573                }
 574        }
 575
 576        if (fnew)
 577                list_add_tail(&newchannel->listentry,
 578                              &vmbus_connection.chn_list);
 579        else {
 580                /*
 581                 * Check to see if this is a valid sub-channel.
 582                 */
 583                if (newchannel->offermsg.offer.sub_channel_index == 0) {
 584                        mutex_unlock(&vmbus_connection.channel_mutex);
 585                        /*
 586                         * Don't call free_channel(), because newchannel->kobj
 587                         * is not initialized yet.
 588                         */
 589                        kfree(newchannel);
 590                        WARN_ON_ONCE(1);
 591                        return;
 592                }
 593                /*
 594                 * Process the sub-channel.
 595                 */
 596                newchannel->primary_channel = channel;
 597                spin_lock_irqsave(&channel->lock, flags);
 598                list_add_tail(&newchannel->sc_list, &channel->sc_list);
 599                spin_unlock_irqrestore(&channel->lock, flags);
 600        }
 601
 602        mutex_unlock(&vmbus_connection.channel_mutex);
 603
 604        /*
 605         * vmbus_process_offer() mustn't call channel->sc_creation_callback()
 606         * directly for sub-channels, because sc_creation_callback() ->
 607         * vmbus_open() may never get the host's response to the
 608         * OPEN_CHANNEL message (the host may rescind a channel at any time,
 609         * e.g. in the case of hot removing a NIC), and vmbus_onoffer_rescind()
 610         * may not wake up the vmbus_open() as it's blocked due to a non-zero
 611         * vmbus_connection.offer_in_progress, and finally we have a deadlock.
 612         *
 613         * The above is also true for primary channels, if the related device
 614         * drivers use sync probing mode by default.
 615         *
 616         * And, usually the handling of primary channels and sub-channels can
 617         * depend on each other, so we should offload them to different
 618         * workqueues to avoid possible deadlock, e.g. in sync-probing mode,
 619         * NIC1's netvsc_subchan_work() can race with NIC2's netvsc_probe() ->
 620         * rtnl_lock(), and causes deadlock: the former gets the rtnl_lock
 621         * and waits for all the sub-channels to appear, but the latter
 622         * can't get the rtnl_lock and this blocks the handling of
 623         * sub-channels.
 624         */
 625        INIT_WORK(&newchannel->add_channel_work, vmbus_add_channel_work);
 626        wq = fnew ? vmbus_connection.handle_primary_chan_wq :
 627                    vmbus_connection.handle_sub_chan_wq;
 628        queue_work(wq, &newchannel->add_channel_work);
 629}
 630
 631/*
 632 * We use this state to statically distribute the channel interrupt load.
 633 */
 634static int next_numa_node_id;
 635/*
 636 * init_vp_index() accesses global variables like next_numa_node_id, and
 637 * it can run concurrently for primary channels and sub-channels: see
 638 * vmbus_process_offer(), so we need the lock to protect the global
 639 * variables.
 640 */
 641static DEFINE_SPINLOCK(bind_channel_to_cpu_lock);
 642
 643/*
 644 * Starting with Win8, we can statically distribute the incoming
 645 * channel interrupt load by binding a channel to VCPU.
 646 * We distribute the interrupt loads to one or more NUMA nodes based on
 647 * the channel's affinity_policy.
 648 *
 649 * For pre-win8 hosts or non-performance critical channels we assign the
 650 * first CPU in the first NUMA node.
 651 */
 652static void init_vp_index(struct vmbus_channel *channel, u16 dev_type)
 653{
 654        u32 cur_cpu;
 655        bool perf_chn = vmbus_devs[dev_type].perf_device;
 656        struct vmbus_channel *primary = channel->primary_channel;
 657        int next_node;
 658        cpumask_var_t available_mask;
 659        struct cpumask *alloced_mask;
 660
 661        if ((vmbus_proto_version == VERSION_WS2008) ||
 662            (vmbus_proto_version == VERSION_WIN7) || (!perf_chn) ||
 663            !alloc_cpumask_var(&available_mask, GFP_KERNEL)) {
 664                /*
 665                 * Prior to win8, all channel interrupts are
 666                 * delivered on cpu 0.
 667                 * Also if the channel is not a performance critical
 668                 * channel, bind it to cpu 0.
 669                 * In case alloc_cpumask_var() fails, bind it to cpu 0.
 670                 */
 671                channel->numa_node = 0;
 672                channel->target_cpu = 0;
 673                channel->target_vp = hv_cpu_number_to_vp_number(0);
 674                return;
 675        }
 676
 677        spin_lock(&bind_channel_to_cpu_lock);
 678
 679        /*
 680         * Based on the channel affinity policy, we will assign the NUMA
 681         * nodes.
 682         */
 683
 684        if ((channel->affinity_policy == HV_BALANCED) || (!primary)) {
 685                while (true) {
 686                        next_node = next_numa_node_id++;
 687                        if (next_node == nr_node_ids) {
 688                                next_node = next_numa_node_id = 0;
 689                                continue;
 690                        }
 691                        if (cpumask_empty(cpumask_of_node(next_node)))
 692                                continue;
 693                        break;
 694                }
 695                channel->numa_node = next_node;
 696                primary = channel;
 697        }
 698        alloced_mask = &hv_context.hv_numa_map[primary->numa_node];
 699
 700        if (cpumask_weight(alloced_mask) ==
 701            cpumask_weight(cpumask_of_node(primary->numa_node))) {
 702                /*
 703                 * We have cycled through all the CPUs in the node;
 704                 * reset the alloced map.
 705                 */
 706                cpumask_clear(alloced_mask);
 707        }
 708
 709        cpumask_xor(available_mask, alloced_mask,
 710                    cpumask_of_node(primary->numa_node));
 711
 712        cur_cpu = -1;
 713
 714        if (primary->affinity_policy == HV_LOCALIZED) {
 715                /*
 716                 * Normally Hyper-V host doesn't create more subchannels
 717                 * than there are VCPUs on the node but it is possible when not
 718                 * all present VCPUs on the node are initialized by guest.
 719                 * Clear the alloced_cpus_in_node to start over.
 720                 */
 721                if (cpumask_equal(&primary->alloced_cpus_in_node,
 722                                  cpumask_of_node(primary->numa_node)))
 723                        cpumask_clear(&primary->alloced_cpus_in_node);
 724        }
 725
 726        while (true) {
 727                cur_cpu = cpumask_next(cur_cpu, available_mask);
 728                if (cur_cpu >= nr_cpu_ids) {
 729                        cur_cpu = -1;
 730                        cpumask_copy(available_mask,
 731                                     cpumask_of_node(primary->numa_node));
 732                        continue;
 733                }
 734
 735                if (primary->affinity_policy == HV_LOCALIZED) {
 736                        /*
 737                         * NOTE: in the case of sub-channel, we clear the
 738                         * sub-channel related bit(s) in
 739                         * primary->alloced_cpus_in_node in
 740                         * hv_process_channel_removal(), so when we
 741                         * reload drivers like hv_netvsc in SMP guest, here
 742                         * we're able to re-allocate
 743                         * bit from primary->alloced_cpus_in_node.
 744                         */
 745                        if (!cpumask_test_cpu(cur_cpu,
 746                                              &primary->alloced_cpus_in_node)) {
 747                                cpumask_set_cpu(cur_cpu,
 748                                                &primary->alloced_cpus_in_node);
 749                                cpumask_set_cpu(cur_cpu, alloced_mask);
 750                                break;
 751                        }
 752                } else {
 753                        cpumask_set_cpu(cur_cpu, alloced_mask);
 754                        break;
 755                }
 756        }
 757
 758        channel->target_cpu = cur_cpu;
 759        channel->target_vp = hv_cpu_number_to_vp_number(cur_cpu);
 760
 761        spin_unlock(&bind_channel_to_cpu_lock);
 762
 763        free_cpumask_var(available_mask);
 764}
 765
 766static void vmbus_wait_for_unload(void)
 767{
 768        int cpu;
 769        void *page_addr;
 770        struct hv_message *msg;
 771        struct vmbus_channel_message_header *hdr;
 772        u32 message_type;
 773
 774        /*
 775         * CHANNELMSG_UNLOAD_RESPONSE is always delivered to the CPU which was
 776         * used for initial contact or to CPU0 depending on host version. When
 777         * we're crashing on a different CPU let's hope that IRQ handler on
 778         * the cpu which receives CHANNELMSG_UNLOAD_RESPONSE is still
 779         * functional and vmbus_unload_response() will complete
 780         * vmbus_connection.unload_event. If not, the last thing we can do is
 781         * read message pages for all CPUs directly.
 782         */
 783        while (1) {
 784                if (completion_done(&vmbus_connection.unload_event))
 785                        break;
 786
 787                for_each_online_cpu(cpu) {
 788                        struct hv_per_cpu_context *hv_cpu
 789                                = per_cpu_ptr(hv_context.cpu_context, cpu);
 790
 791                        page_addr = hv_cpu->synic_message_page;
 792                        msg = (struct hv_message *)page_addr
 793                                + VMBUS_MESSAGE_SINT;
 794
 795                        message_type = READ_ONCE(msg->header.message_type);
 796                        if (message_type == HVMSG_NONE)
 797                                continue;
 798
 799                        hdr = (struct vmbus_channel_message_header *)
 800                                msg->u.payload;
 801
 802                        if (hdr->msgtype == CHANNELMSG_UNLOAD_RESPONSE)
 803                                complete(&vmbus_connection.unload_event);
 804
 805                        vmbus_signal_eom(msg, message_type);
 806                }
 807
 808                mdelay(10);
 809        }
 810
 811        /*
 812         * We're crashing and already got the UNLOAD_RESPONSE, cleanup all
 813         * maybe-pending messages on all CPUs to be able to receive new
 814         * messages after we reconnect.
 815         */
 816        for_each_online_cpu(cpu) {
 817                struct hv_per_cpu_context *hv_cpu
 818                        = per_cpu_ptr(hv_context.cpu_context, cpu);
 819
 820                page_addr = hv_cpu->synic_message_page;
 821                msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
 822                msg->header.message_type = HVMSG_NONE;
 823        }
 824}
 825
 826/*
 827 * vmbus_unload_response - Handler for the unload response.
 828 */
 829static void vmbus_unload_response(struct vmbus_channel_message_header *hdr)
 830{
 831        /*
 832         * This is a global event; just wakeup the waiting thread.
 833         * Once we successfully unload, we can cleanup the monitor state.
 834         */
 835        complete(&vmbus_connection.unload_event);
 836}
 837
 838void vmbus_initiate_unload(bool crash)
 839{
 840        struct vmbus_channel_message_header hdr;
 841
 842        /* Pre-Win2012R2 hosts don't support reconnect */
 843        if (vmbus_proto_version < VERSION_WIN8_1)
 844                return;
 845
 846        init_completion(&vmbus_connection.unload_event);
 847        memset(&hdr, 0, sizeof(struct vmbus_channel_message_header));
 848        hdr.msgtype = CHANNELMSG_UNLOAD;
 849        vmbus_post_msg(&hdr, sizeof(struct vmbus_channel_message_header),
 850                       !crash);
 851
 852        /*
 853         * vmbus_initiate_unload() is also called on crash and the crash can be
 854         * happening in an interrupt context, where scheduling is impossible.
 855         */
 856        if (!crash)
 857                wait_for_completion(&vmbus_connection.unload_event);
 858        else
 859                vmbus_wait_for_unload();
 860}
 861
 862static void check_ready_for_resume_event(void)
 863{
 864        /*
 865         * If all the old primary channels have been fixed up, then it's safe
 866         * to resume.
 867         */
 868        if (atomic_dec_and_test(&vmbus_connection.nr_chan_fixup_on_resume))
 869                complete(&vmbus_connection.ready_for_resume_event);
 870}
 871
 872static void vmbus_setup_channel_state(struct vmbus_channel *channel,
 873                                      struct vmbus_channel_offer_channel *offer)
 874{
 875        /*
 876         * Setup state for signalling the host.
 877         */
 878        channel->sig_event = VMBUS_EVENT_CONNECTION_ID;
 879
 880        if (vmbus_proto_version != VERSION_WS2008) {
 881                channel->is_dedicated_interrupt =
 882                                (offer->is_dedicated_interrupt != 0);
 883                channel->sig_event = offer->connection_id;
 884        }
 885
 886        memcpy(&channel->offermsg, offer,
 887               sizeof(struct vmbus_channel_offer_channel));
 888        channel->monitor_grp = (u8)offer->monitorid / 32;
 889        channel->monitor_bit = (u8)offer->monitorid % 32;
 890}
 891
 892/*
 893 * find_primary_channel_by_offer - Get the channel object given the new offer.
 894 * This is only used in the resume path of hibernation.
 895 */
 896static struct vmbus_channel *
 897find_primary_channel_by_offer(const struct vmbus_channel_offer_channel *offer)
 898{
 899        struct vmbus_channel *channel = NULL, *iter;
 900        const guid_t *inst1, *inst2;
 901
 902        /* Ignore sub-channel offers. */
 903        if (offer->offer.sub_channel_index != 0)
 904                return NULL;
 905
 906        mutex_lock(&vmbus_connection.channel_mutex);
 907
 908        list_for_each_entry(iter, &vmbus_connection.chn_list, listentry) {
 909                inst1 = &iter->offermsg.offer.if_instance;
 910                inst2 = &offer->offer.if_instance;
 911
 912                if (guid_equal(inst1, inst2)) {
 913                        channel = iter;
 914                        break;
 915                }
 916        }
 917
 918        mutex_unlock(&vmbus_connection.channel_mutex);
 919
 920        return channel;
 921}
 922
 923/*
 924 * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 925 *
 926 */
 927static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 928{
 929        struct vmbus_channel_offer_channel *offer;
 930        struct vmbus_channel *oldchannel, *newchannel;
 931        size_t offer_sz;
 932
 933        offer = (struct vmbus_channel_offer_channel *)hdr;
 934
 935        trace_vmbus_onoffer(offer);
 936
 937        oldchannel = find_primary_channel_by_offer(offer);
 938
 939        if (oldchannel != NULL) {
 940                atomic_dec(&vmbus_connection.offer_in_progress);
 941
 942                /*
 943                 * We're resuming from hibernation: all the sub-channel and
 944                 * hv_sock channels we had before the hibernation should have
 945                 * been cleaned up, and now we must be seeing a re-offered
 946                 * primary channel that we had before the hibernation.
 947                 */
 948
 949                WARN_ON(oldchannel->offermsg.child_relid != INVALID_RELID);
 950                /* Fix up the relid. */
 951                oldchannel->offermsg.child_relid = offer->child_relid;
 952
 953                offer_sz = sizeof(*offer);
 954                if (memcmp(offer, &oldchannel->offermsg, offer_sz) == 0) {
 955                        check_ready_for_resume_event();
 956                        return;
 957                }
 958
 959                /*
 960                 * This is not an error, since the host can also change the
 961                 * other field(s) of the offer, e.g. on WS RS5 (Build 17763),
 962                 * the offer->connection_id of the Mellanox VF vmbus device
 963                 * can change when the host reoffers the device upon resume.
 964                 */
 965                pr_debug("vmbus offer changed: relid=%d\n",
 966                         offer->child_relid);
 967
 968                print_hex_dump_debug("Old vmbus offer: ", DUMP_PREFIX_OFFSET,
 969                                     16, 4, &oldchannel->offermsg, offer_sz,
 970                                     false);
 971                print_hex_dump_debug("New vmbus offer: ", DUMP_PREFIX_OFFSET,
 972                                     16, 4, offer, offer_sz, false);
 973
 974                /* Fix up the old channel. */
 975                vmbus_setup_channel_state(oldchannel, offer);
 976
 977                check_ready_for_resume_event();
 978
 979                return;
 980        }
 981
 982        /* Allocate the channel object and save this offer. */
 983        newchannel = alloc_channel();
 984        if (!newchannel) {
 985                vmbus_release_relid(offer->child_relid);
 986                atomic_dec(&vmbus_connection.offer_in_progress);
 987                pr_err("Unable to allocate channel object\n");
 988                return;
 989        }
 990
 991        vmbus_setup_channel_state(newchannel, offer);
 992
 993        vmbus_process_offer(newchannel);
 994}
 995
 996static void check_ready_for_suspend_event(void)
 997{
 998        /*
 999         * If all the sub-channels or hv_sock channels have been cleaned up,
1000         * then it's safe to suspend.
1001         */
1002        if (atomic_dec_and_test(&vmbus_connection.nr_chan_close_on_suspend))
1003                complete(&vmbus_connection.ready_for_suspend_event);
1004}
1005
1006/*
1007 * vmbus_onoffer_rescind - Rescind offer handler.
1008 *
1009 * We queue a work item to process this offer synchronously
1010 */
1011static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
1012{
1013        struct vmbus_channel_rescind_offer *rescind;
1014        struct vmbus_channel *channel;
1015        struct device *dev;
1016        bool clean_up_chan_for_suspend;
1017
1018        rescind = (struct vmbus_channel_rescind_offer *)hdr;
1019
1020        trace_vmbus_onoffer_rescind(rescind);
1021
1022        /*
1023         * The offer msg and the corresponding rescind msg
1024         * from the host are guranteed to be ordered -
1025         * offer comes in first and then the rescind.
1026         * Since we process these events in work elements,
1027         * and with preemption, we may end up processing
1028         * the events out of order. Given that we handle these
1029         * work elements on the same CPU, this is possible only
1030         * in the case of preemption. In any case wait here
1031         * until the offer processing has moved beyond the
1032         * point where the channel is discoverable.
1033         */
1034
1035        while (atomic_read(&vmbus_connection.offer_in_progress) != 0) {
1036                /*
1037                 * We wait here until any channel offer is currently
1038                 * being processed.
1039                 */
1040                msleep(1);
1041        }
1042
1043        mutex_lock(&vmbus_connection.channel_mutex);
1044        channel = relid2channel(rescind->child_relid);
1045        mutex_unlock(&vmbus_connection.channel_mutex);
1046
1047        if (channel == NULL) {
1048                /*
1049                 * We failed in processing the offer message;
1050                 * we would have cleaned up the relid in that
1051                 * failure path.
1052                 */
1053                return;
1054        }
1055
1056        clean_up_chan_for_suspend = is_hvsock_channel(channel) ||
1057                                    is_sub_channel(channel);
1058        /*
1059         * Before setting channel->rescind in vmbus_rescind_cleanup(), we
1060         * should make sure the channel callback is not running any more.
1061         */
1062        vmbus_reset_channel_cb(channel);
1063
1064        /*
1065         * Now wait for offer handling to complete.
1066         */
1067        vmbus_rescind_cleanup(channel);
1068        while (READ_ONCE(channel->probe_done) == false) {
1069                /*
1070                 * We wait here until any channel offer is currently
1071                 * being processed.
1072                 */
1073                msleep(1);
1074        }
1075
1076        /*
1077         * At this point, the rescind handling can proceed safely.
1078         */
1079
1080        if (channel->device_obj) {
1081                if (channel->chn_rescind_callback) {
1082                        channel->chn_rescind_callback(channel);
1083
1084                        if (clean_up_chan_for_suspend)
1085                                check_ready_for_suspend_event();
1086
1087                        return;
1088                }
1089                /*
1090                 * We will have to unregister this device from the
1091                 * driver core.
1092                 */
1093                dev = get_device(&channel->device_obj->device);
1094                if (dev) {
1095                        vmbus_device_unregister(channel->device_obj);
1096                        put_device(dev);
1097                }
1098        }
1099        if (channel->primary_channel != NULL) {
1100                /*
1101                 * Sub-channel is being rescinded. Following is the channel
1102                 * close sequence when initiated from the driveri (refer to
1103                 * vmbus_close() for details):
1104                 * 1. Close all sub-channels first
1105                 * 2. Then close the primary channel.
1106                 */
1107                mutex_lock(&vmbus_connection.channel_mutex);
1108                if (channel->state == CHANNEL_OPEN_STATE) {
1109                        /*
1110                         * The channel is currently not open;
1111                         * it is safe for us to cleanup the channel.
1112                         */
1113                        hv_process_channel_removal(channel);
1114                } else {
1115                        complete(&channel->rescind_event);
1116                }
1117                mutex_unlock(&vmbus_connection.channel_mutex);
1118        }
1119
1120        /* The "channel" may have been freed. Do not access it any longer. */
1121
1122        if (clean_up_chan_for_suspend)
1123                check_ready_for_suspend_event();
1124}
1125
1126void vmbus_hvsock_device_unregister(struct vmbus_channel *channel)
1127{
1128        BUG_ON(!is_hvsock_channel(channel));
1129
1130        /* We always get a rescind msg when a connection is closed. */
1131        while (!READ_ONCE(channel->probe_done) || !READ_ONCE(channel->rescind))
1132                msleep(1);
1133
1134        vmbus_device_unregister(channel->device_obj);
1135}
1136EXPORT_SYMBOL_GPL(vmbus_hvsock_device_unregister);
1137
1138
1139/*
1140 * vmbus_onoffers_delivered -
1141 * This is invoked when all offers have been delivered.
1142 *
1143 * Nothing to do here.
1144 */
1145static void vmbus_onoffers_delivered(
1146                        struct vmbus_channel_message_header *hdr)
1147{
1148}
1149
1150/*
1151 * vmbus_onopen_result - Open result handler.
1152 *
1153 * This is invoked when we received a response to our channel open request.
1154 * Find the matching request, copy the response and signal the requesting
1155 * thread.
1156 */
1157static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
1158{
1159        struct vmbus_channel_open_result *result;
1160        struct vmbus_channel_msginfo *msginfo;
1161        struct vmbus_channel_message_header *requestheader;
1162        struct vmbus_channel_open_channel *openmsg;
1163        unsigned long flags;
1164
1165        result = (struct vmbus_channel_open_result *)hdr;
1166
1167        trace_vmbus_onopen_result(result);
1168
1169        /*
1170         * Find the open msg, copy the result and signal/unblock the wait event
1171         */
1172        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1173
1174        list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1175                                msglistentry) {
1176                requestheader =
1177                        (struct vmbus_channel_message_header *)msginfo->msg;
1178
1179                if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
1180                        openmsg =
1181                        (struct vmbus_channel_open_channel *)msginfo->msg;
1182                        if (openmsg->child_relid == result->child_relid &&
1183                            openmsg->openid == result->openid) {
1184                                memcpy(&msginfo->response.open_result,
1185                                       result,
1186                                       sizeof(
1187                                        struct vmbus_channel_open_result));
1188                                complete(&msginfo->waitevent);
1189                                break;
1190                        }
1191                }
1192        }
1193        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1194}
1195
1196/*
1197 * vmbus_ongpadl_created - GPADL created handler.
1198 *
1199 * This is invoked when we received a response to our gpadl create request.
1200 * Find the matching request, copy the response and signal the requesting
1201 * thread.
1202 */
1203static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
1204{
1205        struct vmbus_channel_gpadl_created *gpadlcreated;
1206        struct vmbus_channel_msginfo *msginfo;
1207        struct vmbus_channel_message_header *requestheader;
1208        struct vmbus_channel_gpadl_header *gpadlheader;
1209        unsigned long flags;
1210
1211        gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
1212
1213        trace_vmbus_ongpadl_created(gpadlcreated);
1214
1215        /*
1216         * Find the establish msg, copy the result and signal/unblock the wait
1217         * event
1218         */
1219        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1220
1221        list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1222                                msglistentry) {
1223                requestheader =
1224                        (struct vmbus_channel_message_header *)msginfo->msg;
1225
1226                if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
1227                        gpadlheader =
1228                        (struct vmbus_channel_gpadl_header *)requestheader;
1229
1230                        if ((gpadlcreated->child_relid ==
1231                             gpadlheader->child_relid) &&
1232                            (gpadlcreated->gpadl == gpadlheader->gpadl)) {
1233                                memcpy(&msginfo->response.gpadl_created,
1234                                       gpadlcreated,
1235                                       sizeof(
1236                                        struct vmbus_channel_gpadl_created));
1237                                complete(&msginfo->waitevent);
1238                                break;
1239                        }
1240                }
1241        }
1242        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1243}
1244
1245/*
1246 * vmbus_ongpadl_torndown - GPADL torndown handler.
1247 *
1248 * This is invoked when we received a response to our gpadl teardown request.
1249 * Find the matching request, copy the response and signal the requesting
1250 * thread.
1251 */
1252static void vmbus_ongpadl_torndown(
1253                        struct vmbus_channel_message_header *hdr)
1254{
1255        struct vmbus_channel_gpadl_torndown *gpadl_torndown;
1256        struct vmbus_channel_msginfo *msginfo;
1257        struct vmbus_channel_message_header *requestheader;
1258        struct vmbus_channel_gpadl_teardown *gpadl_teardown;
1259        unsigned long flags;
1260
1261        gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
1262
1263        trace_vmbus_ongpadl_torndown(gpadl_torndown);
1264
1265        /*
1266         * Find the open msg, copy the result and signal/unblock the wait event
1267         */
1268        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1269
1270        list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1271                                msglistentry) {
1272                requestheader =
1273                        (struct vmbus_channel_message_header *)msginfo->msg;
1274
1275                if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
1276                        gpadl_teardown =
1277                        (struct vmbus_channel_gpadl_teardown *)requestheader;
1278
1279                        if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
1280                                memcpy(&msginfo->response.gpadl_torndown,
1281                                       gpadl_torndown,
1282                                       sizeof(
1283                                        struct vmbus_channel_gpadl_torndown));
1284                                complete(&msginfo->waitevent);
1285                                break;
1286                        }
1287                }
1288        }
1289        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1290}
1291
1292/*
1293 * vmbus_onversion_response - Version response handler
1294 *
1295 * This is invoked when we received a response to our initiate contact request.
1296 * Find the matching request, copy the response and signal the requesting
1297 * thread.
1298 */
1299static void vmbus_onversion_response(
1300                struct vmbus_channel_message_header *hdr)
1301{
1302        struct vmbus_channel_msginfo *msginfo;
1303        struct vmbus_channel_message_header *requestheader;
1304        struct vmbus_channel_version_response *version_response;
1305        unsigned long flags;
1306
1307        version_response = (struct vmbus_channel_version_response *)hdr;
1308
1309        trace_vmbus_onversion_response(version_response);
1310
1311        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1312
1313        list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1314                                msglistentry) {
1315                requestheader =
1316                        (struct vmbus_channel_message_header *)msginfo->msg;
1317
1318                if (requestheader->msgtype ==
1319                    CHANNELMSG_INITIATE_CONTACT) {
1320                        memcpy(&msginfo->response.version_response,
1321                              version_response,
1322                              sizeof(struct vmbus_channel_version_response));
1323                        complete(&msginfo->waitevent);
1324                }
1325        }
1326        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1327}
1328
1329/* Channel message dispatch table */
1330const struct vmbus_channel_message_table_entry
1331channel_message_table[CHANNELMSG_COUNT] = {
1332        { CHANNELMSG_INVALID,                   0, NULL },
1333        { CHANNELMSG_OFFERCHANNEL,              0, vmbus_onoffer },
1334        { CHANNELMSG_RESCIND_CHANNELOFFER,      0, vmbus_onoffer_rescind },
1335        { CHANNELMSG_REQUESTOFFERS,             0, NULL },
1336        { CHANNELMSG_ALLOFFERS_DELIVERED,       1, vmbus_onoffers_delivered },
1337        { CHANNELMSG_OPENCHANNEL,               0, NULL },
1338        { CHANNELMSG_OPENCHANNEL_RESULT,        1, vmbus_onopen_result },
1339        { CHANNELMSG_CLOSECHANNEL,              0, NULL },
1340        { CHANNELMSG_GPADL_HEADER,              0, NULL },
1341        { CHANNELMSG_GPADL_BODY,                0, NULL },
1342        { CHANNELMSG_GPADL_CREATED,             1, vmbus_ongpadl_created },
1343        { CHANNELMSG_GPADL_TEARDOWN,            0, NULL },
1344        { CHANNELMSG_GPADL_TORNDOWN,            1, vmbus_ongpadl_torndown },
1345        { CHANNELMSG_RELID_RELEASED,            0, NULL },
1346        { CHANNELMSG_INITIATE_CONTACT,          0, NULL },
1347        { CHANNELMSG_VERSION_RESPONSE,          1, vmbus_onversion_response },
1348        { CHANNELMSG_UNLOAD,                    0, NULL },
1349        { CHANNELMSG_UNLOAD_RESPONSE,           1, vmbus_unload_response },
1350        { CHANNELMSG_18,                        0, NULL },
1351        { CHANNELMSG_19,                        0, NULL },
1352        { CHANNELMSG_20,                        0, NULL },
1353        { CHANNELMSG_TL_CONNECT_REQUEST,        0, NULL },
1354};
1355
1356/*
1357 * vmbus_onmessage - Handler for channel protocol messages.
1358 *
1359 * This is invoked in the vmbus worker thread context.
1360 */
1361void vmbus_onmessage(void *context)
1362{
1363        struct hv_message *msg = context;
1364        struct vmbus_channel_message_header *hdr;
1365        int size;
1366
1367        hdr = (struct vmbus_channel_message_header *)msg->u.payload;
1368        size = msg->header.payload_size;
1369
1370        trace_vmbus_on_message(hdr);
1371
1372        if (hdr->msgtype >= CHANNELMSG_COUNT) {
1373                pr_err("Received invalid channel message type %d size %d\n",
1374                           hdr->msgtype, size);
1375                print_hex_dump_bytes("", DUMP_PREFIX_NONE,
1376                                     (unsigned char *)msg->u.payload, size);
1377                return;
1378        }
1379
1380        if (channel_message_table[hdr->msgtype].message_handler)
1381                channel_message_table[hdr->msgtype].message_handler(hdr);
1382        else
1383                pr_err("Unhandled channel message type %d\n", hdr->msgtype);
1384}
1385
1386/*
1387 * vmbus_request_offers - Send a request to get all our pending offers.
1388 */
1389int vmbus_request_offers(void)
1390{
1391        struct vmbus_channel_message_header *msg;
1392        struct vmbus_channel_msginfo *msginfo;
1393        int ret;
1394
1395        msginfo = kmalloc(sizeof(*msginfo) +
1396                          sizeof(struct vmbus_channel_message_header),
1397                          GFP_KERNEL);
1398        if (!msginfo)
1399                return -ENOMEM;
1400
1401        msg = (struct vmbus_channel_message_header *)msginfo->msg;
1402
1403        msg->msgtype = CHANNELMSG_REQUESTOFFERS;
1404
1405        ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_message_header),
1406                             true);
1407
1408        trace_vmbus_request_offers(ret);
1409
1410        if (ret != 0) {
1411                pr_err("Unable to request offers - %d\n", ret);
1412
1413                goto cleanup;
1414        }
1415
1416cleanup:
1417        kfree(msginfo);
1418
1419        return ret;
1420}
1421
1422static void invoke_sc_cb(struct vmbus_channel *primary_channel)
1423{
1424        struct list_head *cur, *tmp;
1425        struct vmbus_channel *cur_channel;
1426
1427        if (primary_channel->sc_creation_callback == NULL)
1428                return;
1429
1430        list_for_each_safe(cur, tmp, &primary_channel->sc_list) {
1431                cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
1432
1433                primary_channel->sc_creation_callback(cur_channel);
1434        }
1435}
1436
1437void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
1438                                void (*sc_cr_cb)(struct vmbus_channel *new_sc))
1439{
1440        primary_channel->sc_creation_callback = sc_cr_cb;
1441}
1442EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
1443
1444bool vmbus_are_subchannels_present(struct vmbus_channel *primary)
1445{
1446        bool ret;
1447
1448        ret = !list_empty(&primary->sc_list);
1449
1450        if (ret) {
1451                /*
1452                 * Invoke the callback on sub-channel creation.
1453                 * This will present a uniform interface to the
1454                 * clients.
1455                 */
1456                invoke_sc_cb(primary);
1457        }
1458
1459        return ret;
1460}
1461EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present);
1462
1463void vmbus_set_chn_rescind_callback(struct vmbus_channel *channel,
1464                void (*chn_rescind_cb)(struct vmbus_channel *))
1465{
1466        channel->chn_rescind_callback = chn_rescind_cb;
1467}
1468EXPORT_SYMBOL_GPL(vmbus_set_chn_rescind_callback);
1469