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 static 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  */
 829 static 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
 838 void 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
 862 static 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
 872 static 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  */
 896 static struct vmbus_channel *
 897 find_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  */
 927 static 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
 996 static 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  */
1011 static 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
1126 void 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 }
1136 EXPORT_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  */
1145 static 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  */
1157 static 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  */
1203 static 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  */
1252 static 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  */
1299 static 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 */
1330 const struct vmbus_channel_message_table_entry
1331 channel_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  */
1361 void 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  */
1389 int 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
1416 cleanup:
1417         kfree(msginfo);
1418
1419         return ret;
1420 }
1421
1422 static 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
1437 void 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 }
1442 EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
1443
1444 bool 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 }
1461 EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present);
1462
1463 void 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 }
1468 EXPORT_SYMBOL_GPL(vmbus_set_chn_rescind_callback);