drivers/hv/channel_mgmt.c

   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
  26 static void init_vp_index(struct vmbus_channel *channel, u16 dev_type);
  27
  28 static 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
 131 static 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  */
 143 static 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
 162 static 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
 172 static 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  */
 204 bool 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
 283 fw_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
 305 EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);
 306
 307 /*
 308  * alloc_channel - Allocate and initialize a vmbus channel object
 309  */
 310 static 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  */
 335 static 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
 343 static 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
 352 static void percpu_channel_deq(void *arg)
 353 {
 354         struct vmbus_channel *channel = arg;
 355
 356         list_del_rcu(&channel->percpu_list);
 357 }
 358
 359
 360 static 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
 374 void 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
 423 void 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. */
 437 static 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
 509 err_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  */
 547 static 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  */
 634 static 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  */
 641 static 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  */
 652 static 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
 766 #define UNLOAD_DELAY_UNIT_MS    10              /* 10 milliseconds */
 767 #define UNLOAD_WAIT_MS          (100*1000)      /* 100 seconds */
 768 #define UNLOAD_WAIT_LOOPS       (UNLOAD_WAIT_MS/UNLOAD_DELAY_UNIT_MS)
 769 #define UNLOAD_MSG_MS           (5*1000)        /* Every 5 seconds */
 770 #define UNLOAD_MSG_LOOPS        (UNLOAD_MSG_MS/UNLOAD_DELAY_UNIT_MS)
 771
 772 static void vmbus_wait_for_unload(void)
 773 {
 774         int cpu;
 775         void *page_addr;
 776         struct hv_message *msg;
 777         struct vmbus_channel_message_header *hdr;
 778         u32 message_type, i;
 779
 780         /*
 781          * CHANNELMSG_UNLOAD_RESPONSE is always delivered to the CPU which was
 782          * used for initial contact or to CPU0 depending on host version. When
 783          * we're crashing on a different CPU let's hope that IRQ handler on
 784          * the cpu which receives CHANNELMSG_UNLOAD_RESPONSE is still
 785          * functional and vmbus_unload_response() will complete
 786          * vmbus_connection.unload_event. If not, the last thing we can do is
 787          * read message pages for all CPUs directly.
 788          *
 789          * Wait up to 100 seconds since an Azure host must writeback any dirty
 790          * data in its disk cache before the VMbus UNLOAD request will
 791          * complete. This flushing has been empirically observed to take up
 792          * to 50 seconds in cases with a lot of dirty data, so allow additional
 793          * leeway and for inaccuracies in mdelay(). But eventually time out so
 794          * that the panic path can't get hung forever in case the response
 795          * message isn't seen.
 796          */
 797         for (i = 1; i <= UNLOAD_WAIT_LOOPS; i++) {
 798                 if (completion_done(&vmbus_connection.unload_event))
 799                         goto completed;
 800
 801                 for_each_online_cpu(cpu) {
 802                         struct hv_per_cpu_context *hv_cpu
 803                                 = per_cpu_ptr(hv_context.cpu_context, cpu);
 804
 805                         page_addr = hv_cpu->synic_message_page;
 806                         msg = (struct hv_message *)page_addr
 807                                 + VMBUS_MESSAGE_SINT;
 808
 809                         message_type = READ_ONCE(msg->header.message_type);
 810                         if (message_type == HVMSG_NONE)
 811                                 continue;
 812
 813                         hdr = (struct vmbus_channel_message_header *)
 814                                 msg->u.payload;
 815
 816                         if (hdr->msgtype == CHANNELMSG_UNLOAD_RESPONSE)
 817                                 complete(&vmbus_connection.unload_event);
 818
 819                         vmbus_signal_eom(msg, message_type);
 820                 }
 821
 822                 /*
 823                  * Give a notice periodically so someone watching the
 824                  * serial output won't think it is completely hung.
 825                  */
 826                 if (!(i % UNLOAD_MSG_LOOPS))
 827                         pr_notice("Waiting for VMBus UNLOAD to complete\n");
 828
 829                 mdelay(UNLOAD_DELAY_UNIT_MS);
 830         }
 831         pr_err("Continuing even though VMBus UNLOAD did not complete\n");
 832
 833 completed:
 834         /*
 835          * We're crashing and already got the UNLOAD_RESPONSE, cleanup all
 836          * maybe-pending messages on all CPUs to be able to receive new
 837          * messages after we reconnect.
 838          */
 839         for_each_online_cpu(cpu) {
 840                 struct hv_per_cpu_context *hv_cpu
 841                         = per_cpu_ptr(hv_context.cpu_context, cpu);
 842
 843                 page_addr = hv_cpu->synic_message_page;
 844                 msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
 845                 msg->header.message_type = HVMSG_NONE;
 846         }
 847 }
 848
 849 /*
 850  * vmbus_unload_response - Handler for the unload response.
 851  */
 852 static void vmbus_unload_response(struct vmbus_channel_message_header *hdr)
 853 {
 854         /*
 855          * This is a global event; just wakeup the waiting thread.
 856          * Once we successfully unload, we can cleanup the monitor state.
 857          */
 858         complete(&vmbus_connection.unload_event);
 859 }
 860
 861 void vmbus_initiate_unload(bool crash)
 862 {
 863         struct vmbus_channel_message_header hdr;
 864
 865         if (xchg(&vmbus_connection.conn_state, DISCONNECTED) == DISCONNECTED)
 866                 return;
 867
 868         /* Pre-Win2012R2 hosts don't support reconnect */
 869         if (vmbus_proto_version < VERSION_WIN8_1)
 870                 return;
 871
 872         init_completion(&vmbus_connection.unload_event);
 873         memset(&hdr, 0, sizeof(struct vmbus_channel_message_header));
 874         hdr.msgtype = CHANNELMSG_UNLOAD;
 875         vmbus_post_msg(&hdr, sizeof(struct vmbus_channel_message_header),
 876                        !crash);
 877
 878         /*
 879          * vmbus_initiate_unload() is also called on crash and the crash can be
 880          * happening in an interrupt context, where scheduling is impossible.
 881          */
 882         if (!crash)
 883                 wait_for_completion(&vmbus_connection.unload_event);
 884         else
 885                 vmbus_wait_for_unload();
 886 }
 887
 888 static void check_ready_for_resume_event(void)
 889 {
 890         /*
 891          * If all the old primary channels have been fixed up, then it's safe
 892          * to resume.
 893          */
 894         if (atomic_dec_and_test(&vmbus_connection.nr_chan_fixup_on_resume))
 895                 complete(&vmbus_connection.ready_for_resume_event);
 896 }
 897
 898 static void vmbus_setup_channel_state(struct vmbus_channel *channel,
 899                                       struct vmbus_channel_offer_channel *offer)
 900 {
 901         /*
 902          * Setup state for signalling the host.
 903          */
 904         channel->sig_event = VMBUS_EVENT_CONNECTION_ID;
 905
 906         if (vmbus_proto_version != VERSION_WS2008) {
 907                 channel->is_dedicated_interrupt =
 908                                 (offer->is_dedicated_interrupt != 0);
 909                 channel->sig_event = offer->connection_id;
 910         }
 911
 912         memcpy(&channel->offermsg, offer,
 913                sizeof(struct vmbus_channel_offer_channel));
 914         channel->monitor_grp = (u8)offer->monitorid / 32;
 915         channel->monitor_bit = (u8)offer->monitorid % 32;
 916 }
 917
 918 /*
 919  * find_primary_channel_by_offer - Get the channel object given the new offer.
 920  * This is only used in the resume path of hibernation.
 921  */
 922 static struct vmbus_channel *
 923 find_primary_channel_by_offer(const struct vmbus_channel_offer_channel *offer)
 924 {
 925         struct vmbus_channel *channel = NULL, *iter;
 926         const guid_t *inst1, *inst2;
 927
 928         /* Ignore sub-channel offers. */
 929         if (offer->offer.sub_channel_index != 0)
 930                 return NULL;
 931
 932         mutex_lock(&vmbus_connection.channel_mutex);
 933
 934         list_for_each_entry(iter, &vmbus_connection.chn_list, listentry) {
 935                 inst1 = &iter->offermsg.offer.if_instance;
 936                 inst2 = &offer->offer.if_instance;
 937
 938                 if (guid_equal(inst1, inst2)) {
 939                         channel = iter;
 940                         break;
 941                 }
 942         }
 943
 944         mutex_unlock(&vmbus_connection.channel_mutex);
 945
 946         return channel;
 947 }
 948
 949 /*
 950  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 951  *
 952  */
 953 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 954 {
 955         struct vmbus_channel_offer_channel *offer;
 956         struct vmbus_channel *oldchannel, *newchannel;
 957         size_t offer_sz;
 958
 959         offer = (struct vmbus_channel_offer_channel *)hdr;
 960
 961         trace_vmbus_onoffer(offer);
 962
 963         oldchannel = find_primary_channel_by_offer(offer);
 964
 965         if (oldchannel != NULL) {
 966                 atomic_dec(&vmbus_connection.offer_in_progress);
 967
 968                 /*
 969                  * We're resuming from hibernation: all the sub-channel and
 970                  * hv_sock channels we had before the hibernation should have
 971                  * been cleaned up, and now we must be seeing a re-offered
 972                  * primary channel that we had before the hibernation.
 973                  */
 974
 975                 WARN_ON(oldchannel->offermsg.child_relid != INVALID_RELID);
 976                 /* Fix up the relid. */
 977                 oldchannel->offermsg.child_relid = offer->child_relid;
 978
 979                 offer_sz = sizeof(*offer);
 980                 if (memcmp(offer, &oldchannel->offermsg, offer_sz) == 0) {
 981                         check_ready_for_resume_event();
 982                         return;
 983                 }
 984
 985                 /*
 986                  * This is not an error, since the host can also change the
 987                  * other field(s) of the offer, e.g. on WS RS5 (Build 17763),
 988                  * the offer->connection_id of the Mellanox VF vmbus device
 989                  * can change when the host reoffers the device upon resume.
 990                  */
 991                 pr_debug("vmbus offer changed: relid=%d\n",
 992                          offer->child_relid);
 993
 994                 print_hex_dump_debug("Old vmbus offer: ", DUMP_PREFIX_OFFSET,
 995                                      16, 4, &oldchannel->offermsg, offer_sz,
 996                                      false);
 997                 print_hex_dump_debug("New vmbus offer: ", DUMP_PREFIX_OFFSET,
 998                                      16, 4, offer, offer_sz, false);
 999
1000                 /* Fix up the old channel. */
1001                 vmbus_setup_channel_state(oldchannel, offer);
1002
1003                 check_ready_for_resume_event();
1004
1005                 return;
1006         }
1007
1008         /* Allocate the channel object and save this offer. */
1009         newchannel = alloc_channel();
1010         if (!newchannel) {
1011                 vmbus_release_relid(offer->child_relid);
1012                 atomic_dec(&vmbus_connection.offer_in_progress);
1013                 pr_err("Unable to allocate channel object\n");
1014                 return;
1015         }
1016
1017         vmbus_setup_channel_state(newchannel, offer);
1018
1019         vmbus_process_offer(newchannel);
1020 }
1021
1022 static void check_ready_for_suspend_event(void)
1023 {
1024         /*
1025          * If all the sub-channels or hv_sock channels have been cleaned up,
1026          * then it's safe to suspend.
1027          */
1028         if (atomic_dec_and_test(&vmbus_connection.nr_chan_close_on_suspend))
1029                 complete(&vmbus_connection.ready_for_suspend_event);
1030 }
1031
1032 /*
1033  * vmbus_onoffer_rescind - Rescind offer handler.
1034  *
1035  * We queue a work item to process this offer synchronously
1036  */
1037 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
1038 {
1039         struct vmbus_channel_rescind_offer *rescind;
1040         struct vmbus_channel *channel;
1041         struct device *dev;
1042         bool clean_up_chan_for_suspend;
1043
1044         rescind = (struct vmbus_channel_rescind_offer *)hdr;
1045
1046         trace_vmbus_onoffer_rescind(rescind);
1047
1048         /*
1049          * The offer msg and the corresponding rescind msg
1050          * from the host are guranteed to be ordered -
1051          * offer comes in first and then the rescind.
1052          * Since we process these events in work elements,
1053          * and with preemption, we may end up processing
1054          * the events out of order. Given that we handle these
1055          * work elements on the same CPU, this is possible only
1056          * in the case of preemption. In any case wait here
1057          * until the offer processing has moved beyond the
1058          * point where the channel is discoverable.
1059          */
1060
1061         while (atomic_read(&vmbus_connection.offer_in_progress) != 0) {
1062                 /*
1063                  * We wait here until any channel offer is currently
1064                  * being processed.
1065                  */
1066                 msleep(1);
1067         }
1068
1069         mutex_lock(&vmbus_connection.channel_mutex);
1070         channel = relid2channel(rescind->child_relid);
1071         mutex_unlock(&vmbus_connection.channel_mutex);
1072
1073         if (channel == NULL) {
1074                 /*
1075                  * We failed in processing the offer message;
1076                  * we would have cleaned up the relid in that
1077                  * failure path.
1078                  */
1079                 return;
1080         }
1081
1082         clean_up_chan_for_suspend = is_hvsock_channel(channel) ||
1083                                     is_sub_channel(channel);
1084         /*
1085          * Before setting channel->rescind in vmbus_rescind_cleanup(), we
1086          * should make sure the channel callback is not running any more.
1087          */
1088         vmbus_reset_channel_cb(channel);
1089
1090         /*
1091          * Now wait for offer handling to complete.
1092          */
1093         vmbus_rescind_cleanup(channel);
1094         while (READ_ONCE(channel->probe_done) == false) {
1095                 /*
1096                  * We wait here until any channel offer is currently
1097                  * being processed.
1098                  */
1099                 msleep(1);
1100         }
1101
1102         /*
1103          * At this point, the rescind handling can proceed safely.
1104          */
1105
1106         if (channel->device_obj) {
1107                 if (channel->chn_rescind_callback) {
1108                         channel->chn_rescind_callback(channel);
1109
1110                         if (clean_up_chan_for_suspend)
1111                                 check_ready_for_suspend_event();
1112
1113                         return;
1114                 }
1115                 /*
1116                  * We will have to unregister this device from the
1117                  * driver core.
1118                  */
1119                 dev = get_device(&channel->device_obj->device);
1120                 if (dev) {
1121                         vmbus_device_unregister(channel->device_obj);
1122                         put_device(dev);
1123                 }
1124         } else if (channel->primary_channel != NULL) {
1125                 /*
1126                  * Sub-channel is being rescinded. Following is the channel
1127                  * close sequence when initiated from the driveri (refer to
1128                  * vmbus_close() for details):
1129                  * 1. Close all sub-channels first
1130                  * 2. Then close the primary channel.
1131                  */
1132                 mutex_lock(&vmbus_connection.channel_mutex);
1133                 if (channel->state == CHANNEL_OPEN_STATE) {
1134                         /*
1135                          * The channel is currently not open;
1136                          * it is safe for us to cleanup the channel.
1137                          */
1138                         hv_process_channel_removal(channel);
1139                 } else {
1140                         complete(&channel->rescind_event);
1141                 }
1142                 mutex_unlock(&vmbus_connection.channel_mutex);
1143         }
1144
1145         /* The "channel" may have been freed. Do not access it any longer. */
1146
1147         if (clean_up_chan_for_suspend)
1148                 check_ready_for_suspend_event();
1149 }
1150
1151 void vmbus_hvsock_device_unregister(struct vmbus_channel *channel)
1152 {
1153         BUG_ON(!is_hvsock_channel(channel));
1154
1155         /* We always get a rescind msg when a connection is closed. */
1156         while (!READ_ONCE(channel->probe_done) || !READ_ONCE(channel->rescind))
1157                 msleep(1);
1158
1159         vmbus_device_unregister(channel->device_obj);
1160 }
1161 EXPORT_SYMBOL_GPL(vmbus_hvsock_device_unregister);
1162
1163
1164 /*
1165  * vmbus_onoffers_delivered -
1166  * This is invoked when all offers have been delivered.
1167  *
1168  * Nothing to do here.
1169  */
1170 static void vmbus_onoffers_delivered(
1171                         struct vmbus_channel_message_header *hdr)
1172 {
1173 }
1174
1175 /*
1176  * vmbus_onopen_result - Open result handler.
1177  *
1178  * This is invoked when we received a response to our channel open request.
1179  * Find the matching request, copy the response and signal the requesting
1180  * thread.
1181  */
1182 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
1183 {
1184         struct vmbus_channel_open_result *result;
1185         struct vmbus_channel_msginfo *msginfo;
1186         struct vmbus_channel_message_header *requestheader;
1187         struct vmbus_channel_open_channel *openmsg;
1188         unsigned long flags;
1189
1190         result = (struct vmbus_channel_open_result *)hdr;
1191
1192         trace_vmbus_onopen_result(result);
1193
1194         /*
1195          * Find the open msg, copy the result and signal/unblock the wait event
1196          */
1197         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1198
1199         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1200                                 msglistentry) {
1201                 requestheader =
1202                         (struct vmbus_channel_message_header *)msginfo->msg;
1203
1204                 if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
1205                         openmsg =
1206                         (struct vmbus_channel_open_channel *)msginfo->msg;
1207                         if (openmsg->child_relid == result->child_relid &&
1208                             openmsg->openid == result->openid) {
1209                                 memcpy(&msginfo->response.open_result,
1210                                        result,
1211                                        sizeof(
1212                                         struct vmbus_channel_open_result));
1213                                 complete(&msginfo->waitevent);
1214                                 break;
1215                         }
1216                 }
1217         }
1218         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1219 }
1220
1221 /*
1222  * vmbus_ongpadl_created - GPADL created handler.
1223  *
1224  * This is invoked when we received a response to our gpadl create request.
1225  * Find the matching request, copy the response and signal the requesting
1226  * thread.
1227  */
1228 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
1229 {
1230         struct vmbus_channel_gpadl_created *gpadlcreated;
1231         struct vmbus_channel_msginfo *msginfo;
1232         struct vmbus_channel_message_header *requestheader;
1233         struct vmbus_channel_gpadl_header *gpadlheader;
1234         unsigned long flags;
1235
1236         gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
1237
1238         trace_vmbus_ongpadl_created(gpadlcreated);
1239
1240         /*
1241          * Find the establish msg, copy the result and signal/unblock the wait
1242          * event
1243          */
1244         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1245
1246         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1247                                 msglistentry) {
1248                 requestheader =
1249                         (struct vmbus_channel_message_header *)msginfo->msg;
1250
1251                 if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
1252                         gpadlheader =
1253                         (struct vmbus_channel_gpadl_header *)requestheader;
1254
1255                         if ((gpadlcreated->child_relid ==
1256                              gpadlheader->child_relid) &&
1257                             (gpadlcreated->gpadl == gpadlheader->gpadl)) {
1258                                 memcpy(&msginfo->response.gpadl_created,
1259                                        gpadlcreated,
1260                                        sizeof(
1261                                         struct vmbus_channel_gpadl_created));
1262                                 complete(&msginfo->waitevent);
1263                                 break;
1264                         }
1265                 }
1266         }
1267         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1268 }
1269
1270 /*
1271  * vmbus_ongpadl_torndown - GPADL torndown handler.
1272  *
1273  * This is invoked when we received a response to our gpadl teardown request.
1274  * Find the matching request, copy the response and signal the requesting
1275  * thread.
1276  */
1277 static void vmbus_ongpadl_torndown(
1278                         struct vmbus_channel_message_header *hdr)
1279 {
1280         struct vmbus_channel_gpadl_torndown *gpadl_torndown;
1281         struct vmbus_channel_msginfo *msginfo;
1282         struct vmbus_channel_message_header *requestheader;
1283         struct vmbus_channel_gpadl_teardown *gpadl_teardown;
1284         unsigned long flags;
1285
1286         gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
1287
1288         trace_vmbus_ongpadl_torndown(gpadl_torndown);
1289
1290         /*
1291          * Find the open msg, copy the result and signal/unblock the wait event
1292          */
1293         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1294
1295         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1296                                 msglistentry) {
1297                 requestheader =
1298                         (struct vmbus_channel_message_header *)msginfo->msg;
1299
1300                 if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
1301                         gpadl_teardown =
1302                         (struct vmbus_channel_gpadl_teardown *)requestheader;
1303
1304                         if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
1305                                 memcpy(&msginfo->response.gpadl_torndown,
1306                                        gpadl_torndown,
1307                                        sizeof(
1308                                         struct vmbus_channel_gpadl_torndown));
1309                                 complete(&msginfo->waitevent);
1310                                 break;
1311                         }
1312                 }
1313         }
1314         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1315 }
1316
1317 /*
1318  * vmbus_onversion_response - Version response handler
1319  *
1320  * This is invoked when we received a response to our initiate contact request.
1321  * Find the matching request, copy the response and signal the requesting
1322  * thread.
1323  */
1324 static void vmbus_onversion_response(
1325                 struct vmbus_channel_message_header *hdr)
1326 {
1327         struct vmbus_channel_msginfo *msginfo;
1328         struct vmbus_channel_message_header *requestheader;
1329         struct vmbus_channel_version_response *version_response;
1330         unsigned long flags;
1331
1332         version_response = (struct vmbus_channel_version_response *)hdr;
1333
1334         trace_vmbus_onversion_response(version_response);
1335
1336         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1337
1338         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1339                                 msglistentry) {
1340                 requestheader =
1341                         (struct vmbus_channel_message_header *)msginfo->msg;
1342
1343                 if (requestheader->msgtype ==
1344                     CHANNELMSG_INITIATE_CONTACT) {
1345                         memcpy(&msginfo->response.version_response,
1346                               version_response,
1347                               sizeof(struct vmbus_channel_version_response));
1348                         complete(&msginfo->waitevent);
1349                 }
1350         }
1351         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1352 }
1353
1354 /* Channel message dispatch table */
1355 const struct vmbus_channel_message_table_entry
1356 channel_message_table[CHANNELMSG_COUNT] = {
1357         { CHANNELMSG_INVALID,                   0, NULL },
1358         { CHANNELMSG_OFFERCHANNEL,              0, vmbus_onoffer },
1359         { CHANNELMSG_RESCIND_CHANNELOFFER,      0, vmbus_onoffer_rescind },
1360         { CHANNELMSG_REQUESTOFFERS,             0, NULL },
1361         { CHANNELMSG_ALLOFFERS_DELIVERED,       1, vmbus_onoffers_delivered },
1362         { CHANNELMSG_OPENCHANNEL,               0, NULL },
1363         { CHANNELMSG_OPENCHANNEL_RESULT,        1, vmbus_onopen_result },
1364         { CHANNELMSG_CLOSECHANNEL,              0, NULL },
1365         { CHANNELMSG_GPADL_HEADER,              0, NULL },
1366         { CHANNELMSG_GPADL_BODY,                0, NULL },
1367         { CHANNELMSG_GPADL_CREATED,             1, vmbus_ongpadl_created },
1368         { CHANNELMSG_GPADL_TEARDOWN,            0, NULL },
1369         { CHANNELMSG_GPADL_TORNDOWN,            1, vmbus_ongpadl_torndown },
1370         { CHANNELMSG_RELID_RELEASED,            0, NULL },
1371         { CHANNELMSG_INITIATE_CONTACT,          0, NULL },
1372         { CHANNELMSG_VERSION_RESPONSE,          1, vmbus_onversion_response },
1373         { CHANNELMSG_UNLOAD,                    0, NULL },
1374         { CHANNELMSG_UNLOAD_RESPONSE,           1, vmbus_unload_response },
1375         { CHANNELMSG_18,                        0, NULL },
1376         { CHANNELMSG_19,                        0, NULL },
1377         { CHANNELMSG_20,                        0, NULL },
1378         { CHANNELMSG_TL_CONNECT_REQUEST,        0, NULL },
1379         { CHANNELMSG_22,                        0, NULL },
1380         { CHANNELMSG_TL_CONNECT_RESULT,         0, NULL },
1381 };
1382
1383 /*
1384  * vmbus_onmessage - Handler for channel protocol messages.
1385  *
1386  * This is invoked in the vmbus worker thread context.
1387  */
1388 void vmbus_onmessage(void *context)
1389 {
1390         struct hv_message *msg = context;
1391         struct vmbus_channel_message_header *hdr;
1392
1393         hdr = (struct vmbus_channel_message_header *)msg->u.payload;
1394
1395         trace_vmbus_on_message(hdr);
1396
1397         /*
1398          * vmbus_on_msg_dpc() makes sure the hdr->msgtype here can not go
1399          * out of bound and the message_handler pointer can not be NULL.
1400          */
1401         channel_message_table[hdr->msgtype].message_handler(hdr);
1402 }
1403
1404 /*
1405  * vmbus_request_offers - Send a request to get all our pending offers.
1406  */
1407 int vmbus_request_offers(void)
1408 {
1409         struct vmbus_channel_message_header *msg;
1410         struct vmbus_channel_msginfo *msginfo;
1411         int ret;
1412
1413         msginfo = kmalloc(sizeof(*msginfo) +
1414                           sizeof(struct vmbus_channel_message_header),
1415                           GFP_KERNEL);
1416         if (!msginfo)
1417                 return -ENOMEM;
1418
1419         msg = (struct vmbus_channel_message_header *)msginfo->msg;
1420
1421         msg->msgtype = CHANNELMSG_REQUESTOFFERS;
1422
1423         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_message_header),
1424                              true);
1425
1426         trace_vmbus_request_offers(ret);
1427
1428         if (ret != 0) {
1429                 pr_err("Unable to request offers - %d\n", ret);
1430
1431                 goto cleanup;
1432         }
1433
1434 cleanup:
1435         kfree(msginfo);
1436
1437         return ret;
1438 }
1439
1440 static void invoke_sc_cb(struct vmbus_channel *primary_channel)
1441 {
1442         struct list_head *cur, *tmp;
1443         struct vmbus_channel *cur_channel;
1444
1445         if (primary_channel->sc_creation_callback == NULL)
1446                 return;
1447
1448         list_for_each_safe(cur, tmp, &primary_channel->sc_list) {
1449                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
1450
1451                 primary_channel->sc_creation_callback(cur_channel);
1452         }
1453 }
1454
1455 void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
1456                                 void (*sc_cr_cb)(struct vmbus_channel *new_sc))
1457 {
1458         primary_channel->sc_creation_callback = sc_cr_cb;
1459 }
1460 EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
1461
1462 bool vmbus_are_subchannels_present(struct vmbus_channel *primary)
1463 {
1464         bool ret;
1465
1466         ret = !list_empty(&primary->sc_list);
1467
1468         if (ret) {
1469                 /*
1470                  * Invoke the callback on sub-channel creation.
1471                  * This will present a uniform interface to the
1472                  * clients.
1473                  */
1474                 invoke_sc_cb(primary);
1475         }
1476
1477         return ret;
1478 }
1479 EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present);
1480
1481 void vmbus_set_chn_rescind_callback(struct vmbus_channel *channel,
1482                 void (*chn_rescind_cb)(struct vmbus_channel *))
1483 {
1484         channel->chn_rescind_callback = chn_rescind_cb;
1485 }
1486 EXPORT_SYMBOL_GPL(vmbus_set_chn_rescind_callback);