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/cpu.h>
  22 #include <linux/hyperv.h>
  23 #include <asm/mshyperv.h>
  24 #include <linux/sched/isolation.h>
  25
  26 #include "hyperv_vmbus.h"
  27
  28 static void init_vp_index(struct vmbus_channel *channel);
  29
  30 const struct vmbus_device vmbus_devs[] = {
  31         /* IDE */
  32         { .dev_type = HV_IDE,
  33           HV_IDE_GUID,
  34           .perf_device = true,
  35           .allowed_in_isolated = false,
  36         },
  37
  38         /* SCSI */
  39         { .dev_type = HV_SCSI,
  40           HV_SCSI_GUID,
  41           .perf_device = true,
  42           .allowed_in_isolated = true,
  43         },
  44
  45         /* Fibre Channel */
  46         { .dev_type = HV_FC,
  47           HV_SYNTHFC_GUID,
  48           .perf_device = true,
  49           .allowed_in_isolated = false,
  50         },
  51
  52         /* Synthetic NIC */
  53         { .dev_type = HV_NIC,
  54           HV_NIC_GUID,
  55           .perf_device = true,
  56           .allowed_in_isolated = true,
  57         },
  58
  59         /* Network Direct */
  60         { .dev_type = HV_ND,
  61           HV_ND_GUID,
  62           .perf_device = true,
  63           .allowed_in_isolated = false,
  64         },
  65
  66         /* PCIE */
  67         { .dev_type = HV_PCIE,
  68           HV_PCIE_GUID,
  69           .perf_device = false,
  70           .allowed_in_isolated = false,
  71         },
  72
  73         /* Synthetic Frame Buffer */
  74         { .dev_type = HV_FB,
  75           HV_SYNTHVID_GUID,
  76           .perf_device = false,
  77           .allowed_in_isolated = false,
  78         },
  79
  80         /* Synthetic Keyboard */
  81         { .dev_type = HV_KBD,
  82           HV_KBD_GUID,
  83           .perf_device = false,
  84           .allowed_in_isolated = false,
  85         },
  86
  87         /* Synthetic MOUSE */
  88         { .dev_type = HV_MOUSE,
  89           HV_MOUSE_GUID,
  90           .perf_device = false,
  91           .allowed_in_isolated = false,
  92         },
  93
  94         /* KVP */
  95         { .dev_type = HV_KVP,
  96           HV_KVP_GUID,
  97           .perf_device = false,
  98           .allowed_in_isolated = false,
  99         },
 100
 101         /* Time Synch */
 102         { .dev_type = HV_TS,
 103           HV_TS_GUID,
 104           .perf_device = false,
 105           .allowed_in_isolated = true,
 106         },
 107
 108         /* Heartbeat */
 109         { .dev_type = HV_HB,
 110           HV_HEART_BEAT_GUID,
 111           .perf_device = false,
 112           .allowed_in_isolated = true,
 113         },
 114
 115         /* Shutdown */
 116         { .dev_type = HV_SHUTDOWN,
 117           HV_SHUTDOWN_GUID,
 118           .perf_device = false,
 119           .allowed_in_isolated = true,
 120         },
 121
 122         /* File copy */
 123         { .dev_type = HV_FCOPY,
 124           HV_FCOPY_GUID,
 125           .perf_device = false,
 126           .allowed_in_isolated = false,
 127         },
 128
 129         /* Backup */
 130         { .dev_type = HV_BACKUP,
 131           HV_VSS_GUID,
 132           .perf_device = false,
 133           .allowed_in_isolated = false,
 134         },
 135
 136         /* Dynamic Memory */
 137         { .dev_type = HV_DM,
 138           HV_DM_GUID,
 139           .perf_device = false,
 140           .allowed_in_isolated = false,
 141         },
 142
 143         /* Unknown GUID */
 144         { .dev_type = HV_UNKNOWN,
 145           .perf_device = false,
 146           .allowed_in_isolated = false,
 147         },
 148 };
 149
 150 static const struct {
 151         guid_t guid;
 152 } vmbus_unsupported_devs[] = {
 153         { HV_AVMA1_GUID },
 154         { HV_AVMA2_GUID },
 155         { HV_RDV_GUID   },
 156         { HV_IMC_GUID   },
 157 };
 158
 159 /*
 160  * The rescinded channel may be blocked waiting for a response from the host;
 161  * take care of that.
 162  */
 163 static void vmbus_rescind_cleanup(struct vmbus_channel *channel)
 164 {
 165         struct vmbus_channel_msginfo *msginfo;
 166         unsigned long flags;
 167
 168
 169         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 170         channel->rescind = true;
 171         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 172                                 msglistentry) {
 173
 174                 if (msginfo->waiting_channel == channel) {
 175                         complete(&msginfo->waitevent);
 176                         break;
 177                 }
 178         }
 179         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 180 }
 181
 182 static bool is_unsupported_vmbus_devs(const guid_t *guid)
 183 {
 184         int i;
 185
 186         for (i = 0; i < ARRAY_SIZE(vmbus_unsupported_devs); i++)
 187                 if (guid_equal(guid, &vmbus_unsupported_devs[i].guid))
 188                         return true;
 189         return false;
 190 }
 191
 192 static u16 hv_get_dev_type(const struct vmbus_channel *channel)
 193 {
 194         const guid_t *guid = &channel->offermsg.offer.if_type;
 195         u16 i;
 196
 197         if (is_hvsock_channel(channel) || is_unsupported_vmbus_devs(guid))
 198                 return HV_UNKNOWN;
 199
 200         for (i = HV_IDE; i < HV_UNKNOWN; i++) {
 201                 if (guid_equal(guid, &vmbus_devs[i].guid))
 202                         return i;
 203         }
 204         pr_info("Unknown GUID: %pUl\n", guid);
 205         return i;
 206 }
 207
 208 /**
 209  * vmbus_prep_negotiate_resp() - Create default response for Negotiate message
 210  * @icmsghdrp: Pointer to msg header structure
 211  * @buf: Raw buffer channel data
 212  * @buflen: Length of the raw buffer channel data.
 213  * @fw_version: The framework versions we can support.
 214  * @fw_vercnt: The size of @fw_version.
 215  * @srv_version: The service versions we can support.
 216  * @srv_vercnt: The size of @srv_version.
 217  * @nego_fw_version: The selected framework version.
 218  * @nego_srv_version: The selected service version.
 219  *
 220  * Note: Versions are given in decreasing order.
 221  *
 222  * Set up and fill in default negotiate response message.
 223  * Mainly used by Hyper-V drivers.
 224  */
 225 bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp, u8 *buf,
 226                                 u32 buflen, const int *fw_version, int fw_vercnt,
 227                                 const int *srv_version, int srv_vercnt,
 228                                 int *nego_fw_version, int *nego_srv_version)
 229 {
 230         int icframe_major, icframe_minor;
 231         int icmsg_major, icmsg_minor;
 232         int fw_major, fw_minor;
 233         int srv_major, srv_minor;
 234         int i, j;
 235         bool found_match = false;
 236         struct icmsg_negotiate *negop;
 237
 238         /* Check that there's enough space for icframe_vercnt, icmsg_vercnt */
 239         if (buflen < ICMSG_HDR + offsetof(struct icmsg_negotiate, reserved)) {
 240                 pr_err_ratelimited("Invalid icmsg negotiate\n");
 241                 return false;
 242         }
 243
 244         icmsghdrp->icmsgsize = 0x10;
 245         negop = (struct icmsg_negotiate *)&buf[ICMSG_HDR];
 246
 247         icframe_major = negop->icframe_vercnt;
 248         icframe_minor = 0;
 249
 250         icmsg_major = negop->icmsg_vercnt;
 251         icmsg_minor = 0;
 252
 253         /* Validate negop packet */
 254         if (icframe_major > IC_VERSION_NEGOTIATION_MAX_VER_COUNT ||
 255             icmsg_major > IC_VERSION_NEGOTIATION_MAX_VER_COUNT ||
 256             ICMSG_NEGOTIATE_PKT_SIZE(icframe_major, icmsg_major) > buflen) {
 257                 pr_err_ratelimited("Invalid icmsg negotiate - icframe_major: %u, icmsg_major: %u\n",
 258                                    icframe_major, icmsg_major);
 259                 goto fw_error;
 260         }
 261
 262         /*
 263          * Select the framework version number we will
 264          * support.
 265          */
 266
 267         for (i = 0; i < fw_vercnt; i++) {
 268                 fw_major = (fw_version[i] >> 16);
 269                 fw_minor = (fw_version[i] & 0xFFFF);
 270
 271                 for (j = 0; j < negop->icframe_vercnt; j++) {
 272                         if ((negop->icversion_data[j].major == fw_major) &&
 273                             (negop->icversion_data[j].minor == fw_minor)) {
 274                                 icframe_major = negop->icversion_data[j].major;
 275                                 icframe_minor = negop->icversion_data[j].minor;
 276                                 found_match = true;
 277                                 break;
 278                         }
 279                 }
 280
 281                 if (found_match)
 282                         break;
 283         }
 284
 285         if (!found_match)
 286                 goto fw_error;
 287
 288         found_match = false;
 289
 290         for (i = 0; i < srv_vercnt; i++) {
 291                 srv_major = (srv_version[i] >> 16);
 292                 srv_minor = (srv_version[i] & 0xFFFF);
 293
 294                 for (j = negop->icframe_vercnt;
 295                         (j < negop->icframe_vercnt + negop->icmsg_vercnt);
 296                         j++) {
 297
 298                         if ((negop->icversion_data[j].major == srv_major) &&
 299                                 (negop->icversion_data[j].minor == srv_minor)) {
 300
 301                                 icmsg_major = negop->icversion_data[j].major;
 302                                 icmsg_minor = negop->icversion_data[j].minor;
 303                                 found_match = true;
 304                                 break;
 305                         }
 306                 }
 307
 308                 if (found_match)
 309                         break;
 310         }
 311
 312         /*
 313          * Respond with the framework and service
 314          * version numbers we can support.
 315          */
 316
 317 fw_error:
 318         if (!found_match) {
 319                 negop->icframe_vercnt = 0;
 320                 negop->icmsg_vercnt = 0;
 321         } else {
 322                 negop->icframe_vercnt = 1;
 323                 negop->icmsg_vercnt = 1;
 324         }
 325
 326         if (nego_fw_version)
 327                 *nego_fw_version = (icframe_major << 16) | icframe_minor;
 328
 329         if (nego_srv_version)
 330                 *nego_srv_version = (icmsg_major << 16) | icmsg_minor;
 331
 332         negop->icversion_data[0].major = icframe_major;
 333         negop->icversion_data[0].minor = icframe_minor;
 334         negop->icversion_data[1].major = icmsg_major;
 335         negop->icversion_data[1].minor = icmsg_minor;
 336         return found_match;
 337 }
 338 EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);
 339
 340 /*
 341  * alloc_channel - Allocate and initialize a vmbus channel object
 342  */
 343 static struct vmbus_channel *alloc_channel(void)
 344 {
 345         struct vmbus_channel *channel;
 346
 347         channel = kzalloc(sizeof(*channel), GFP_ATOMIC);
 348         if (!channel)
 349                 return NULL;
 350
 351         spin_lock_init(&channel->sched_lock);
 352         init_completion(&channel->rescind_event);
 353
 354         INIT_LIST_HEAD(&channel->sc_list);
 355
 356         tasklet_init(&channel->callback_event,
 357                      vmbus_on_event, (unsigned long)channel);
 358
 359         hv_ringbuffer_pre_init(channel);
 360
 361         return channel;
 362 }
 363
 364 /*
 365  * free_channel - Release the resources used by the vmbus channel object
 366  */
 367 static void free_channel(struct vmbus_channel *channel)
 368 {
 369         tasklet_kill(&channel->callback_event);
 370         vmbus_remove_channel_attr_group(channel);
 371
 372         kobject_put(&channel->kobj);
 373 }
 374
 375 void vmbus_channel_map_relid(struct vmbus_channel *channel)
 376 {
 377         if (WARN_ON(channel->offermsg.child_relid >= MAX_CHANNEL_RELIDS))
 378                 return;
 379         /*
 380          * The mapping of the channel's relid is visible from the CPUs that
 381          * execute vmbus_chan_sched() by the time that vmbus_chan_sched() will
 382          * execute:
 383          *
 384          *  (a) In the "normal (i.e., not resuming from hibernation)" path,
 385          *      the full barrier in virt_store_mb() guarantees that the store
 386          *      is propagated to all CPUs before the add_channel_work work
 387          *      is queued.  In turn, add_channel_work is queued before the
 388          *      channel's ring buffer is allocated/initialized and the
 389          *      OPENCHANNEL message for the channel is sent in vmbus_open().
 390          *      Hyper-V won't start sending the interrupts for the channel
 391          *      before the OPENCHANNEL message is acked.  The memory barrier
 392          *      in vmbus_chan_sched() -> sync_test_and_clear_bit() ensures
 393          *      that vmbus_chan_sched() must find the channel's relid in
 394          *      recv_int_page before retrieving the channel pointer from the
 395          *      array of channels.
 396          *
 397          *  (b) In the "resuming from hibernation" path, the virt_store_mb()
 398          *      guarantees that the store is propagated to all CPUs before
 399          *      the VMBus connection is marked as ready for the resume event
 400          *      (cf. check_ready_for_resume_event()).  The interrupt handler
 401          *      of the VMBus driver and vmbus_chan_sched() can not run before
 402          *      vmbus_bus_resume() has completed execution (cf. resume_noirq).
 403          */
 404         virt_store_mb(
 405                 vmbus_connection.channels[channel->offermsg.child_relid],
 406                 channel);
 407 }
 408
 409 void vmbus_channel_unmap_relid(struct vmbus_channel *channel)
 410 {
 411         if (WARN_ON(channel->offermsg.child_relid >= MAX_CHANNEL_RELIDS))
 412                 return;
 413         WRITE_ONCE(
 414                 vmbus_connection.channels[channel->offermsg.child_relid],
 415                 NULL);
 416 }
 417
 418 static void vmbus_release_relid(u32 relid)
 419 {
 420         struct vmbus_channel_relid_released msg;
 421         int ret;
 422
 423         memset(&msg, 0, sizeof(struct vmbus_channel_relid_released));
 424         msg.child_relid = relid;
 425         msg.header.msgtype = CHANNELMSG_RELID_RELEASED;
 426         ret = vmbus_post_msg(&msg, sizeof(struct vmbus_channel_relid_released),
 427                              true);
 428
 429         trace_vmbus_release_relid(&msg, ret);
 430 }
 431
 432 void hv_process_channel_removal(struct vmbus_channel *channel)
 433 {
 434         lockdep_assert_held(&vmbus_connection.channel_mutex);
 435         BUG_ON(!channel->rescind);
 436
 437         /*
 438          * hv_process_channel_removal() could find INVALID_RELID only for
 439          * hv_sock channels.  See the inline comments in vmbus_onoffer().
 440          */
 441         WARN_ON(channel->offermsg.child_relid == INVALID_RELID &&
 442                 !is_hvsock_channel(channel));
 443
 444         /*
 445          * Upon suspend, an in-use hv_sock channel is removed from the array of
 446          * channels and the relid is invalidated.  After hibernation, when the
 447          * user-space application destroys the channel, it's unnecessary and
 448          * unsafe to remove the channel from the array of channels.  See also
 449          * the inline comments before the call of vmbus_release_relid() below.
 450          */
 451         if (channel->offermsg.child_relid != INVALID_RELID)
 452                 vmbus_channel_unmap_relid(channel);
 453
 454         if (channel->primary_channel == NULL)
 455                 list_del(&channel->listentry);
 456         else
 457                 list_del(&channel->sc_list);
 458
 459         /*
 460          * If this is a "perf" channel, updates the hv_numa_map[] masks so that
 461          * init_vp_index() can (re-)use the CPU.
 462          */
 463         if (hv_is_perf_channel(channel))
 464                 hv_clear_allocated_cpu(channel->target_cpu);
 465
 466         /*
 467          * Upon suspend, an in-use hv_sock channel is marked as "rescinded" and
 468          * the relid is invalidated; after hibernation, when the user-space app
 469          * destroys the channel, the relid is INVALID_RELID, and in this case
 470          * it's unnecessary and unsafe to release the old relid, since the same
 471          * relid can refer to a completely different channel now.
 472          */
 473         if (channel->offermsg.child_relid != INVALID_RELID)
 474                 vmbus_release_relid(channel->offermsg.child_relid);
 475
 476         free_channel(channel);
 477 }
 478
 479 void vmbus_free_channels(void)
 480 {
 481         struct vmbus_channel *channel, *tmp;
 482
 483         list_for_each_entry_safe(channel, tmp, &vmbus_connection.chn_list,
 484                 listentry) {
 485                 /* hv_process_channel_removal() needs this */
 486                 channel->rescind = true;
 487
 488                 vmbus_device_unregister(channel->device_obj);
 489         }
 490 }
 491
 492 /* Note: the function can run concurrently for primary/sub channels. */
 493 static void vmbus_add_channel_work(struct work_struct *work)
 494 {
 495         struct vmbus_channel *newchannel =
 496                 container_of(work, struct vmbus_channel, add_channel_work);
 497         struct vmbus_channel *primary_channel = newchannel->primary_channel;
 498         int ret;
 499
 500         /*
 501          * This state is used to indicate a successful open
 502          * so that when we do close the channel normally, we
 503          * can cleanup properly.
 504          */
 505         newchannel->state = CHANNEL_OPEN_STATE;
 506
 507         if (primary_channel != NULL) {
 508                 /* newchannel is a sub-channel. */
 509                 struct hv_device *dev = primary_channel->device_obj;
 510
 511                 if (vmbus_add_channel_kobj(dev, newchannel))
 512                         goto err_deq_chan;
 513
 514                 if (primary_channel->sc_creation_callback != NULL)
 515                         primary_channel->sc_creation_callback(newchannel);
 516
 517                 newchannel->probe_done = true;
 518                 return;
 519         }
 520
 521         /*
 522          * Start the process of binding the primary channel to the driver
 523          */
 524         newchannel->device_obj = vmbus_device_create(
 525                 &newchannel->offermsg.offer.if_type,
 526                 &newchannel->offermsg.offer.if_instance,
 527                 newchannel);
 528         if (!newchannel->device_obj)
 529                 goto err_deq_chan;
 530
 531         newchannel->device_obj->device_id = newchannel->device_id;
 532         /*
 533          * Add the new device to the bus. This will kick off device-driver
 534          * binding which eventually invokes the device driver's AddDevice()
 535          * method.
 536          */
 537         ret = vmbus_device_register(newchannel->device_obj);
 538
 539         if (ret != 0) {
 540                 pr_err("unable to add child device object (relid %d)\n",
 541                         newchannel->offermsg.child_relid);
 542                 kfree(newchannel->device_obj);
 543                 goto err_deq_chan;
 544         }
 545
 546         newchannel->probe_done = true;
 547         return;
 548
 549 err_deq_chan:
 550         mutex_lock(&vmbus_connection.channel_mutex);
 551
 552         /*
 553          * We need to set the flag, otherwise
 554          * vmbus_onoffer_rescind() can be blocked.
 555          */
 556         newchannel->probe_done = true;
 557
 558         if (primary_channel == NULL)
 559                 list_del(&newchannel->listentry);
 560         else
 561                 list_del(&newchannel->sc_list);
 562
 563         /* vmbus_process_offer() has mapped the channel. */
 564         vmbus_channel_unmap_relid(newchannel);
 565
 566         mutex_unlock(&vmbus_connection.channel_mutex);
 567
 568         vmbus_release_relid(newchannel->offermsg.child_relid);
 569
 570         free_channel(newchannel);
 571 }
 572
 573 /*
 574  * vmbus_process_offer - Process the offer by creating a channel/device
 575  * associated with this offer
 576  */
 577 static void vmbus_process_offer(struct vmbus_channel *newchannel)
 578 {
 579         struct vmbus_channel *channel;
 580         struct workqueue_struct *wq;
 581         bool fnew = true;
 582
 583         /*
 584          * Synchronize vmbus_process_offer() and CPU hotplugging:
 585          *
 586          * CPU1                         CPU2
 587          *
 588          * [vmbus_process_offer()]      [Hot removal of the CPU]
 589          *
 590          * CPU_READ_LOCK                CPUS_WRITE_LOCK
 591          * LOAD cpu_online_mask         SEARCH chn_list
 592          * STORE target_cpu             LOAD target_cpu
 593          * INSERT chn_list              STORE cpu_online_mask
 594          * CPUS_READ_UNLOCK             CPUS_WRITE_UNLOCK
 595          *
 596          * Forbids: CPU1's LOAD from *not* seing CPU2's STORE &&
 597          *              CPU2's SEARCH from *not* seeing CPU1's INSERT
 598          *
 599          * Forbids: CPU2's SEARCH from seeing CPU1's INSERT &&
 600          *              CPU2's LOAD from *not* seing CPU1's STORE
 601          */
 602         cpus_read_lock();
 603
 604         /*
 605          * Serializes the modifications of the chn_list list as well as
 606          * the accesses to next_numa_node_id in init_vp_index().
 607          */
 608         mutex_lock(&vmbus_connection.channel_mutex);
 609
 610         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 611                 if (guid_equal(&channel->offermsg.offer.if_type,
 612                                &newchannel->offermsg.offer.if_type) &&
 613                     guid_equal(&channel->offermsg.offer.if_instance,
 614                                &newchannel->offermsg.offer.if_instance)) {
 615                         fnew = false;
 616                         newchannel->primary_channel = channel;
 617                         break;
 618                 }
 619         }
 620
 621         init_vp_index(newchannel);
 622
 623         /* Remember the channels that should be cleaned up upon suspend. */
 624         if (is_hvsock_channel(newchannel) || is_sub_channel(newchannel))
 625                 atomic_inc(&vmbus_connection.nr_chan_close_on_suspend);
 626
 627         /*
 628          * Now that we have acquired the channel_mutex,
 629          * we can release the potentially racing rescind thread.
 630          */
 631         atomic_dec(&vmbus_connection.offer_in_progress);
 632
 633         if (fnew) {
 634                 list_add_tail(&newchannel->listentry,
 635                               &vmbus_connection.chn_list);
 636         } else {
 637                 /*
 638                  * Check to see if this is a valid sub-channel.
 639                  */
 640                 if (newchannel->offermsg.offer.sub_channel_index == 0) {
 641                         mutex_unlock(&vmbus_connection.channel_mutex);
 642                         cpus_read_unlock();
 643                         /*
 644                          * Don't call free_channel(), because newchannel->kobj
 645                          * is not initialized yet.
 646                          */
 647                         kfree(newchannel);
 648                         WARN_ON_ONCE(1);
 649                         return;
 650                 }
 651                 /*
 652                  * Process the sub-channel.
 653                  */
 654                 list_add_tail(&newchannel->sc_list, &channel->sc_list);
 655         }
 656
 657         vmbus_channel_map_relid(newchannel);
 658
 659         mutex_unlock(&vmbus_connection.channel_mutex);
 660         cpus_read_unlock();
 661
 662         /*
 663          * vmbus_process_offer() mustn't call channel->sc_creation_callback()
 664          * directly for sub-channels, because sc_creation_callback() ->
 665          * vmbus_open() may never get the host's response to the
 666          * OPEN_CHANNEL message (the host may rescind a channel at any time,
 667          * e.g. in the case of hot removing a NIC), and vmbus_onoffer_rescind()
 668          * may not wake up the vmbus_open() as it's blocked due to a non-zero
 669          * vmbus_connection.offer_in_progress, and finally we have a deadlock.
 670          *
 671          * The above is also true for primary channels, if the related device
 672          * drivers use sync probing mode by default.
 673          *
 674          * And, usually the handling of primary channels and sub-channels can
 675          * depend on each other, so we should offload them to different
 676          * workqueues to avoid possible deadlock, e.g. in sync-probing mode,
 677          * NIC1's netvsc_subchan_work() can race with NIC2's netvsc_probe() ->
 678          * rtnl_lock(), and causes deadlock: the former gets the rtnl_lock
 679          * and waits for all the sub-channels to appear, but the latter
 680          * can't get the rtnl_lock and this blocks the handling of
 681          * sub-channels.
 682          */
 683         INIT_WORK(&newchannel->add_channel_work, vmbus_add_channel_work);
 684         wq = fnew ? vmbus_connection.handle_primary_chan_wq :
 685                     vmbus_connection.handle_sub_chan_wq;
 686         queue_work(wq, &newchannel->add_channel_work);
 687 }
 688
 689 /*
 690  * Check if CPUs used by other channels of the same device.
 691  * It should only be called by init_vp_index().
 692  */
 693 static bool hv_cpuself_used(u32 cpu, struct vmbus_channel *chn)
 694 {
 695         struct vmbus_channel *primary = chn->primary_channel;
 696         struct vmbus_channel *sc;
 697
 698         lockdep_assert_held(&vmbus_connection.channel_mutex);
 699
 700         if (!primary)
 701                 return false;
 702
 703         if (primary->target_cpu == cpu)
 704                 return true;
 705
 706         list_for_each_entry(sc, &primary->sc_list, sc_list)
 707                 if (sc != chn && sc->target_cpu == cpu)
 708                         return true;
 709
 710         return false;
 711 }
 712
 713 /*
 714  * We use this state to statically distribute the channel interrupt load.
 715  */
 716 static int next_numa_node_id;
 717
 718 /*
 719  * We can statically distribute the incoming channel interrupt load
 720  * by binding a channel to VCPU.
 721  *
 722  * For non-performance critical channels we assign the VMBUS_CONNECT_CPU.
 723  * Performance critical channels will be distributed evenly among all
 724  * the available NUMA nodes.  Once the node is assigned, we will assign
 725  * the CPU based on a simple round robin scheme.
 726  */
 727 static void init_vp_index(struct vmbus_channel *channel)
 728 {
 729         bool perf_chn = hv_is_perf_channel(channel);
 730         u32 i, ncpu = num_online_cpus();
 731         cpumask_var_t available_mask;
 732         struct cpumask *allocated_mask;
 733         const struct cpumask *hk_mask = housekeeping_cpumask(HK_TYPE_MANAGED_IRQ);
 734         u32 target_cpu;
 735         int numa_node;
 736
 737         if (!perf_chn ||
 738             !alloc_cpumask_var(&available_mask, GFP_KERNEL) ||
 739             cpumask_empty(hk_mask)) {
 740                 /*
 741                  * If the channel is not a performance critical
 742                  * channel, bind it to VMBUS_CONNECT_CPU.
 743                  * In case alloc_cpumask_var() fails, bind it to
 744                  * VMBUS_CONNECT_CPU.
 745                  * If all the cpus are isolated, bind it to
 746                  * VMBUS_CONNECT_CPU.
 747                  */
 748                 channel->target_cpu = VMBUS_CONNECT_CPU;
 749                 if (perf_chn)
 750                         hv_set_allocated_cpu(VMBUS_CONNECT_CPU);
 751                 return;
 752         }
 753
 754         for (i = 1; i <= ncpu + 1; i++) {
 755                 while (true) {
 756                         numa_node = next_numa_node_id++;
 757                         if (numa_node == nr_node_ids) {
 758                                 next_numa_node_id = 0;
 759                                 continue;
 760                         }
 761                         if (cpumask_empty(cpumask_of_node(numa_node)))
 762                                 continue;
 763                         break;
 764                 }
 765                 allocated_mask = &hv_context.hv_numa_map[numa_node];
 766
 767 retry:
 768                 cpumask_xor(available_mask, allocated_mask, cpumask_of_node(numa_node));
 769                 cpumask_and(available_mask, available_mask, hk_mask);
 770
 771                 if (cpumask_empty(available_mask)) {
 772                         /*
 773                          * We have cycled through all the CPUs in the node;
 774                          * reset the allocated map.
 775                          */
 776                         cpumask_clear(allocated_mask);
 777                         goto retry;
 778                 }
 779
 780                 target_cpu = cpumask_first(available_mask);
 781                 cpumask_set_cpu(target_cpu, allocated_mask);
 782
 783                 if (channel->offermsg.offer.sub_channel_index >= ncpu ||
 784                     i > ncpu || !hv_cpuself_used(target_cpu, channel))
 785                         break;
 786         }
 787
 788         channel->target_cpu = target_cpu;
 789
 790         free_cpumask_var(available_mask);
 791 }
 792
 793 #define UNLOAD_DELAY_UNIT_MS    10              /* 10 milliseconds */
 794 #define UNLOAD_WAIT_MS          (100*1000)      /* 100 seconds */
 795 #define UNLOAD_WAIT_LOOPS       (UNLOAD_WAIT_MS/UNLOAD_DELAY_UNIT_MS)
 796 #define UNLOAD_MSG_MS           (5*1000)        /* Every 5 seconds */
 797 #define UNLOAD_MSG_LOOPS        (UNLOAD_MSG_MS/UNLOAD_DELAY_UNIT_MS)
 798
 799 static void vmbus_wait_for_unload(void)
 800 {
 801         int cpu;
 802         void *page_addr;
 803         struct hv_message *msg;
 804         struct vmbus_channel_message_header *hdr;
 805         u32 message_type, i;
 806
 807         /*
 808          * CHANNELMSG_UNLOAD_RESPONSE is always delivered to the CPU which was
 809          * used for initial contact or to CPU0 depending on host version. When
 810          * we're crashing on a different CPU let's hope that IRQ handler on
 811          * the cpu which receives CHANNELMSG_UNLOAD_RESPONSE is still
 812          * functional and vmbus_unload_response() will complete
 813          * vmbus_connection.unload_event. If not, the last thing we can do is
 814          * read message pages for all CPUs directly.
 815          *
 816          * Wait up to 100 seconds since an Azure host must writeback any dirty
 817          * data in its disk cache before the VMbus UNLOAD request will
 818          * complete. This flushing has been empirically observed to take up
 819          * to 50 seconds in cases with a lot of dirty data, so allow additional
 820          * leeway and for inaccuracies in mdelay(). But eventually time out so
 821          * that the panic path can't get hung forever in case the response
 822          * message isn't seen.
 823          */
 824         for (i = 1; i <= UNLOAD_WAIT_LOOPS; i++) {
 825                 if (completion_done(&vmbus_connection.unload_event))
 826                         goto completed;
 827
 828                 for_each_online_cpu(cpu) {
 829                         struct hv_per_cpu_context *hv_cpu
 830                                 = per_cpu_ptr(hv_context.cpu_context, cpu);
 831
 832                         page_addr = hv_cpu->synic_message_page;
 833                         msg = (struct hv_message *)page_addr
 834                                 + VMBUS_MESSAGE_SINT;
 835
 836                         message_type = READ_ONCE(msg->header.message_type);
 837                         if (message_type == HVMSG_NONE)
 838                                 continue;
 839
 840                         hdr = (struct vmbus_channel_message_header *)
 841                                 msg->u.payload;
 842
 843                         if (hdr->msgtype == CHANNELMSG_UNLOAD_RESPONSE)
 844                                 complete(&vmbus_connection.unload_event);
 845
 846                         vmbus_signal_eom(msg, message_type);
 847                 }
 848
 849                 /*
 850                  * Give a notice periodically so someone watching the
 851                  * serial output won't think it is completely hung.
 852                  */
 853                 if (!(i % UNLOAD_MSG_LOOPS))
 854                         pr_notice("Waiting for VMBus UNLOAD to complete\n");
 855
 856                 mdelay(UNLOAD_DELAY_UNIT_MS);
 857         }
 858         pr_err("Continuing even though VMBus UNLOAD did not complete\n");
 859
 860 completed:
 861         /*
 862          * We're crashing and already got the UNLOAD_RESPONSE, cleanup all
 863          * maybe-pending messages on all CPUs to be able to receive new
 864          * messages after we reconnect.
 865          */
 866         for_each_online_cpu(cpu) {
 867                 struct hv_per_cpu_context *hv_cpu
 868                         = per_cpu_ptr(hv_context.cpu_context, cpu);
 869
 870                 page_addr = hv_cpu->synic_message_page;
 871                 msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
 872                 msg->header.message_type = HVMSG_NONE;
 873         }
 874 }
 875
 876 /*
 877  * vmbus_unload_response - Handler for the unload response.
 878  */
 879 static void vmbus_unload_response(struct vmbus_channel_message_header *hdr)
 880 {
 881         /*
 882          * This is a global event; just wakeup the waiting thread.
 883          * Once we successfully unload, we can cleanup the monitor state.
 884          *
 885          * NB.  A malicious or compromised Hyper-V could send a spurious
 886          * message of type CHANNELMSG_UNLOAD_RESPONSE, and trigger a call
 887          * of the complete() below.  Make sure that unload_event has been
 888          * initialized by the time this complete() is executed.
 889          */
 890         complete(&vmbus_connection.unload_event);
 891 }
 892
 893 void vmbus_initiate_unload(bool crash)
 894 {
 895         struct vmbus_channel_message_header hdr;
 896
 897         if (xchg(&vmbus_connection.conn_state, DISCONNECTED) == DISCONNECTED)
 898                 return;
 899
 900         /* Pre-Win2012R2 hosts don't support reconnect */
 901         if (vmbus_proto_version < VERSION_WIN8_1)
 902                 return;
 903
 904         reinit_completion(&vmbus_connection.unload_event);
 905         memset(&hdr, 0, sizeof(struct vmbus_channel_message_header));
 906         hdr.msgtype = CHANNELMSG_UNLOAD;
 907         vmbus_post_msg(&hdr, sizeof(struct vmbus_channel_message_header),
 908                        !crash);
 909
 910         /*
 911          * vmbus_initiate_unload() is also called on crash and the crash can be
 912          * happening in an interrupt context, where scheduling is impossible.
 913          */
 914         if (!crash)
 915                 wait_for_completion(&vmbus_connection.unload_event);
 916         else
 917                 vmbus_wait_for_unload();
 918 }
 919
 920 static void check_ready_for_resume_event(void)
 921 {
 922         /*
 923          * If all the old primary channels have been fixed up, then it's safe
 924          * to resume.
 925          */
 926         if (atomic_dec_and_test(&vmbus_connection.nr_chan_fixup_on_resume))
 927                 complete(&vmbus_connection.ready_for_resume_event);
 928 }
 929
 930 static void vmbus_setup_channel_state(struct vmbus_channel *channel,
 931                                       struct vmbus_channel_offer_channel *offer)
 932 {
 933         /*
 934          * Setup state for signalling the host.
 935          */
 936         channel->sig_event = VMBUS_EVENT_CONNECTION_ID;
 937
 938         channel->is_dedicated_interrupt =
 939                         (offer->is_dedicated_interrupt != 0);
 940         channel->sig_event = offer->connection_id;
 941
 942         memcpy(&channel->offermsg, offer,
 943                sizeof(struct vmbus_channel_offer_channel));
 944         channel->monitor_grp = (u8)offer->monitorid / 32;
 945         channel->monitor_bit = (u8)offer->monitorid % 32;
 946         channel->device_id = hv_get_dev_type(channel);
 947 }
 948
 949 /*
 950  * find_primary_channel_by_offer - Get the channel object given the new offer.
 951  * This is only used in the resume path of hibernation.
 952  */
 953 static struct vmbus_channel *
 954 find_primary_channel_by_offer(const struct vmbus_channel_offer_channel *offer)
 955 {
 956         struct vmbus_channel *channel = NULL, *iter;
 957         const guid_t *inst1, *inst2;
 958
 959         /* Ignore sub-channel offers. */
 960         if (offer->offer.sub_channel_index != 0)
 961                 return NULL;
 962
 963         mutex_lock(&vmbus_connection.channel_mutex);
 964
 965         list_for_each_entry(iter, &vmbus_connection.chn_list, listentry) {
 966                 inst1 = &iter->offermsg.offer.if_instance;
 967                 inst2 = &offer->offer.if_instance;
 968
 969                 if (guid_equal(inst1, inst2)) {
 970                         channel = iter;
 971                         break;
 972                 }
 973         }
 974
 975         mutex_unlock(&vmbus_connection.channel_mutex);
 976
 977         return channel;
 978 }
 979
 980 static bool vmbus_is_valid_offer(const struct vmbus_channel_offer_channel *offer)
 981 {
 982         const guid_t *guid = &offer->offer.if_type;
 983         u16 i;
 984
 985         if (!hv_is_isolation_supported())
 986                 return true;
 987
 988         if (is_hvsock_offer(offer))
 989                 return true;
 990
 991         for (i = 0; i < ARRAY_SIZE(vmbus_devs); i++) {
 992                 if (guid_equal(guid, &vmbus_devs[i].guid))
 993                         return vmbus_devs[i].allowed_in_isolated;
 994         }
 995         return false;
 996 }
 997
 998 /*
 999  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
1000  *
1001  */
1002 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
1003 {
1004         struct vmbus_channel_offer_channel *offer;
1005         struct vmbus_channel *oldchannel, *newchannel;
1006         size_t offer_sz;
1007
1008         offer = (struct vmbus_channel_offer_channel *)hdr;
1009
1010         trace_vmbus_onoffer(offer);
1011
1012         if (!vmbus_is_valid_offer(offer)) {
1013                 pr_err_ratelimited("Invalid offer %d from the host supporting isolation\n",
1014                                    offer->child_relid);
1015                 atomic_dec(&vmbus_connection.offer_in_progress);
1016                 return;
1017         }
1018
1019         oldchannel = find_primary_channel_by_offer(offer);
1020
1021         if (oldchannel != NULL) {
1022                 /*
1023                  * We're resuming from hibernation: all the sub-channel and
1024                  * hv_sock channels we had before the hibernation should have
1025                  * been cleaned up, and now we must be seeing a re-offered
1026                  * primary channel that we had before the hibernation.
1027                  */
1028
1029                 /*
1030                  * { Initially: channel relid = INVALID_RELID,
1031                  *              channels[valid_relid] = NULL }
1032                  *
1033                  * CPU1                                 CPU2
1034                  *
1035                  * [vmbus_onoffer()]                    [vmbus_device_release()]
1036                  *
1037                  * LOCK channel_mutex                   LOCK channel_mutex
1038                  * STORE channel relid = valid_relid    LOAD r1 = channel relid
1039                  * MAP_RELID channel                    if (r1 != INVALID_RELID)
1040                  * UNLOCK channel_mutex                   UNMAP_RELID channel
1041                  *                                      UNLOCK channel_mutex
1042                  *
1043                  * Forbids: r1 == valid_relid &&
1044                  *              channels[valid_relid] == channel
1045                  *
1046                  * Note.  r1 can be INVALID_RELID only for an hv_sock channel.
1047                  * None of the hv_sock channels which were present before the
1048                  * suspend are re-offered upon the resume.  See the WARN_ON()
1049                  * in hv_process_channel_removal().
1050                  */
1051                 mutex_lock(&vmbus_connection.channel_mutex);
1052
1053                 atomic_dec(&vmbus_connection.offer_in_progress);
1054
1055                 WARN_ON(oldchannel->offermsg.child_relid != INVALID_RELID);
1056                 /* Fix up the relid. */
1057                 oldchannel->offermsg.child_relid = offer->child_relid;
1058
1059                 offer_sz = sizeof(*offer);
1060                 if (memcmp(offer, &oldchannel->offermsg, offer_sz) != 0) {
1061                         /*
1062                          * This is not an error, since the host can also change
1063                          * the other field(s) of the offer, e.g. on WS RS5
1064                          * (Build 17763), the offer->connection_id of the
1065                          * Mellanox VF vmbus device can change when the host
1066                          * reoffers the device upon resume.
1067                          */
1068                         pr_debug("vmbus offer changed: relid=%d\n",
1069                                  offer->child_relid);
1070
1071                         print_hex_dump_debug("Old vmbus offer: ",
1072                                              DUMP_PREFIX_OFFSET, 16, 4,
1073                                              &oldchannel->offermsg, offer_sz,
1074                                              false);
1075                         print_hex_dump_debug("New vmbus offer: ",
1076                                              DUMP_PREFIX_OFFSET, 16, 4,
1077                                              offer, offer_sz, false);
1078
1079                         /* Fix up the old channel. */
1080                         vmbus_setup_channel_state(oldchannel, offer);
1081                 }
1082
1083                 /* Add the channel back to the array of channels. */
1084                 vmbus_channel_map_relid(oldchannel);
1085                 check_ready_for_resume_event();
1086
1087                 mutex_unlock(&vmbus_connection.channel_mutex);
1088                 return;
1089         }
1090
1091         /* Allocate the channel object and save this offer. */
1092         newchannel = alloc_channel();
1093         if (!newchannel) {
1094                 vmbus_release_relid(offer->child_relid);
1095                 atomic_dec(&vmbus_connection.offer_in_progress);
1096                 pr_err("Unable to allocate channel object\n");
1097                 return;
1098         }
1099
1100         vmbus_setup_channel_state(newchannel, offer);
1101
1102         vmbus_process_offer(newchannel);
1103 }
1104
1105 static void check_ready_for_suspend_event(void)
1106 {
1107         /*
1108          * If all the sub-channels or hv_sock channels have been cleaned up,
1109          * then it's safe to suspend.
1110          */
1111         if (atomic_dec_and_test(&vmbus_connection.nr_chan_close_on_suspend))
1112                 complete(&vmbus_connection.ready_for_suspend_event);
1113 }
1114
1115 /*
1116  * vmbus_onoffer_rescind - Rescind offer handler.
1117  *
1118  * We queue a work item to process this offer synchronously
1119  */
1120 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
1121 {
1122         struct vmbus_channel_rescind_offer *rescind;
1123         struct vmbus_channel *channel;
1124         struct device *dev;
1125         bool clean_up_chan_for_suspend;
1126
1127         rescind = (struct vmbus_channel_rescind_offer *)hdr;
1128
1129         trace_vmbus_onoffer_rescind(rescind);
1130
1131         /*
1132          * The offer msg and the corresponding rescind msg
1133          * from the host are guranteed to be ordered -
1134          * offer comes in first and then the rescind.
1135          * Since we process these events in work elements,
1136          * and with preemption, we may end up processing
1137          * the events out of order.  We rely on the synchronization
1138          * provided by offer_in_progress and by channel_mutex for
1139          * ordering these events:
1140          *
1141          * { Initially: offer_in_progress = 1 }
1142          *
1143          * CPU1                         CPU2
1144          *
1145          * [vmbus_onoffer()]            [vmbus_onoffer_rescind()]
1146          *
1147          * LOCK channel_mutex           WAIT_ON offer_in_progress == 0
1148          * DECREMENT offer_in_progress  LOCK channel_mutex
1149          * STORE channels[]             LOAD channels[]
1150          * UNLOCK channel_mutex         UNLOCK channel_mutex
1151          *
1152          * Forbids: CPU2's LOAD from *not* seeing CPU1's STORE
1153          */
1154
1155         while (atomic_read(&vmbus_connection.offer_in_progress) != 0) {
1156                 /*
1157                  * We wait here until any channel offer is currently
1158                  * being processed.
1159                  */
1160                 msleep(1);
1161         }
1162
1163         mutex_lock(&vmbus_connection.channel_mutex);
1164         channel = relid2channel(rescind->child_relid);
1165         if (channel != NULL) {
1166                 /*
1167                  * Guarantee that no other instance of vmbus_onoffer_rescind()
1168                  * has got a reference to the channel object.  Synchronize on
1169                  * &vmbus_connection.channel_mutex.
1170                  */
1171                 if (channel->rescind_ref) {
1172                         mutex_unlock(&vmbus_connection.channel_mutex);
1173                         return;
1174                 }
1175                 channel->rescind_ref = true;
1176         }
1177         mutex_unlock(&vmbus_connection.channel_mutex);
1178
1179         if (channel == NULL) {
1180                 /*
1181                  * We failed in processing the offer message;
1182                  * we would have cleaned up the relid in that
1183                  * failure path.
1184                  */
1185                 return;
1186         }
1187
1188         clean_up_chan_for_suspend = is_hvsock_channel(channel) ||
1189                                     is_sub_channel(channel);
1190         /*
1191          * Before setting channel->rescind in vmbus_rescind_cleanup(), we
1192          * should make sure the channel callback is not running any more.
1193          */
1194         vmbus_reset_channel_cb(channel);
1195
1196         /*
1197          * Now wait for offer handling to complete.
1198          */
1199         vmbus_rescind_cleanup(channel);
1200         while (READ_ONCE(channel->probe_done) == false) {
1201                 /*
1202                  * We wait here until any channel offer is currently
1203                  * being processed.
1204                  */
1205                 msleep(1);
1206         }
1207
1208         /*
1209          * At this point, the rescind handling can proceed safely.
1210          */
1211
1212         if (channel->device_obj) {
1213                 if (channel->chn_rescind_callback) {
1214                         channel->chn_rescind_callback(channel);
1215
1216                         if (clean_up_chan_for_suspend)
1217                                 check_ready_for_suspend_event();
1218
1219                         return;
1220                 }
1221                 /*
1222                  * We will have to unregister this device from the
1223                  * driver core.
1224                  */
1225                 dev = get_device(&channel->device_obj->device);
1226                 if (dev) {
1227                         vmbus_device_unregister(channel->device_obj);
1228                         put_device(dev);
1229                 }
1230         } else if (channel->primary_channel != NULL) {
1231                 /*
1232                  * Sub-channel is being rescinded. Following is the channel
1233                  * close sequence when initiated from the driveri (refer to
1234                  * vmbus_close() for details):
1235                  * 1. Close all sub-channels first
1236                  * 2. Then close the primary channel.
1237                  */
1238                 mutex_lock(&vmbus_connection.channel_mutex);
1239                 if (channel->state == CHANNEL_OPEN_STATE) {
1240                         /*
1241                          * The channel is currently not open;
1242                          * it is safe for us to cleanup the channel.
1243                          */
1244                         hv_process_channel_removal(channel);
1245                 } else {
1246                         complete(&channel->rescind_event);
1247                 }
1248                 mutex_unlock(&vmbus_connection.channel_mutex);
1249         }
1250
1251         /* The "channel" may have been freed. Do not access it any longer. */
1252
1253         if (clean_up_chan_for_suspend)
1254                 check_ready_for_suspend_event();
1255 }
1256
1257 void vmbus_hvsock_device_unregister(struct vmbus_channel *channel)
1258 {
1259         BUG_ON(!is_hvsock_channel(channel));
1260
1261         /* We always get a rescind msg when a connection is closed. */
1262         while (!READ_ONCE(channel->probe_done) || !READ_ONCE(channel->rescind))
1263                 msleep(1);
1264
1265         vmbus_device_unregister(channel->device_obj);
1266 }
1267 EXPORT_SYMBOL_GPL(vmbus_hvsock_device_unregister);
1268
1269
1270 /*
1271  * vmbus_onoffers_delivered -
1272  * This is invoked when all offers have been delivered.
1273  *
1274  * Nothing to do here.
1275  */
1276 static void vmbus_onoffers_delivered(
1277                         struct vmbus_channel_message_header *hdr)
1278 {
1279 }
1280
1281 /*
1282  * vmbus_onopen_result - Open result handler.
1283  *
1284  * This is invoked when we received a response to our channel open request.
1285  * Find the matching request, copy the response and signal the requesting
1286  * thread.
1287  */
1288 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
1289 {
1290         struct vmbus_channel_open_result *result;
1291         struct vmbus_channel_msginfo *msginfo;
1292         struct vmbus_channel_message_header *requestheader;
1293         struct vmbus_channel_open_channel *openmsg;
1294         unsigned long flags;
1295
1296         result = (struct vmbus_channel_open_result *)hdr;
1297
1298         trace_vmbus_onopen_result(result);
1299
1300         /*
1301          * Find the open msg, copy the result and signal/unblock the wait event
1302          */
1303         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1304
1305         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1306                                 msglistentry) {
1307                 requestheader =
1308                         (struct vmbus_channel_message_header *)msginfo->msg;
1309
1310                 if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
1311                         openmsg =
1312                         (struct vmbus_channel_open_channel *)msginfo->msg;
1313                         if (openmsg->child_relid == result->child_relid &&
1314                             openmsg->openid == result->openid) {
1315                                 memcpy(&msginfo->response.open_result,
1316                                        result,
1317                                        sizeof(
1318                                         struct vmbus_channel_open_result));
1319                                 complete(&msginfo->waitevent);
1320                                 break;
1321                         }
1322                 }
1323         }
1324         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1325 }
1326
1327 /*
1328  * vmbus_ongpadl_created - GPADL created handler.
1329  *
1330  * This is invoked when we received a response to our gpadl create request.
1331  * Find the matching request, copy the response and signal the requesting
1332  * thread.
1333  */
1334 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
1335 {
1336         struct vmbus_channel_gpadl_created *gpadlcreated;
1337         struct vmbus_channel_msginfo *msginfo;
1338         struct vmbus_channel_message_header *requestheader;
1339         struct vmbus_channel_gpadl_header *gpadlheader;
1340         unsigned long flags;
1341
1342         gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
1343
1344         trace_vmbus_ongpadl_created(gpadlcreated);
1345
1346         /*
1347          * Find the establish msg, copy the result and signal/unblock the wait
1348          * event
1349          */
1350         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1351
1352         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1353                                 msglistentry) {
1354                 requestheader =
1355                         (struct vmbus_channel_message_header *)msginfo->msg;
1356
1357                 if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
1358                         gpadlheader =
1359                         (struct vmbus_channel_gpadl_header *)requestheader;
1360
1361                         if ((gpadlcreated->child_relid ==
1362                              gpadlheader->child_relid) &&
1363                             (gpadlcreated->gpadl == gpadlheader->gpadl)) {
1364                                 memcpy(&msginfo->response.gpadl_created,
1365                                        gpadlcreated,
1366                                        sizeof(
1367                                         struct vmbus_channel_gpadl_created));
1368                                 complete(&msginfo->waitevent);
1369                                 break;
1370                         }
1371                 }
1372         }
1373         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1374 }
1375
1376 /*
1377  * vmbus_onmodifychannel_response - Modify Channel response handler.
1378  *
1379  * This is invoked when we received a response to our channel modify request.
1380  * Find the matching request, copy the response and signal the requesting thread.
1381  */
1382 static void vmbus_onmodifychannel_response(struct vmbus_channel_message_header *hdr)
1383 {
1384         struct vmbus_channel_modifychannel_response *response;
1385         struct vmbus_channel_msginfo *msginfo;
1386         unsigned long flags;
1387
1388         response = (struct vmbus_channel_modifychannel_response *)hdr;
1389
1390         trace_vmbus_onmodifychannel_response(response);
1391
1392         /*
1393          * Find the modify msg, copy the response and signal/unblock the wait event.
1394          */
1395         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1396
1397         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list, msglistentry) {
1398                 struct vmbus_channel_message_header *responseheader =
1399                                 (struct vmbus_channel_message_header *)msginfo->msg;
1400
1401                 if (responseheader->msgtype == CHANNELMSG_MODIFYCHANNEL) {
1402                         struct vmbus_channel_modifychannel *modifymsg;
1403
1404                         modifymsg = (struct vmbus_channel_modifychannel *)msginfo->msg;
1405                         if (modifymsg->child_relid == response->child_relid) {
1406                                 memcpy(&msginfo->response.modify_response, response,
1407                                        sizeof(*response));
1408                                 complete(&msginfo->waitevent);
1409                                 break;
1410                         }
1411                 }
1412         }
1413         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1414 }
1415
1416 /*
1417  * vmbus_ongpadl_torndown - GPADL torndown handler.
1418  *
1419  * This is invoked when we received a response to our gpadl teardown request.
1420  * Find the matching request, copy the response and signal the requesting
1421  * thread.
1422  */
1423 static void vmbus_ongpadl_torndown(
1424                         struct vmbus_channel_message_header *hdr)
1425 {
1426         struct vmbus_channel_gpadl_torndown *gpadl_torndown;
1427         struct vmbus_channel_msginfo *msginfo;
1428         struct vmbus_channel_message_header *requestheader;
1429         struct vmbus_channel_gpadl_teardown *gpadl_teardown;
1430         unsigned long flags;
1431
1432         gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
1433
1434         trace_vmbus_ongpadl_torndown(gpadl_torndown);
1435
1436         /*
1437          * Find the open msg, copy the result and signal/unblock the wait event
1438          */
1439         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1440
1441         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1442                                 msglistentry) {
1443                 requestheader =
1444                         (struct vmbus_channel_message_header *)msginfo->msg;
1445
1446                 if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
1447                         gpadl_teardown =
1448                         (struct vmbus_channel_gpadl_teardown *)requestheader;
1449
1450                         if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
1451                                 memcpy(&msginfo->response.gpadl_torndown,
1452                                        gpadl_torndown,
1453                                        sizeof(
1454                                         struct vmbus_channel_gpadl_torndown));
1455                                 complete(&msginfo->waitevent);
1456                                 break;
1457                         }
1458                 }
1459         }
1460         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1461 }
1462
1463 /*
1464  * vmbus_onversion_response - Version response handler
1465  *
1466  * This is invoked when we received a response to our initiate contact request.
1467  * Find the matching request, copy the response and signal the requesting
1468  * thread.
1469  */
1470 static void vmbus_onversion_response(
1471                 struct vmbus_channel_message_header *hdr)
1472 {
1473         struct vmbus_channel_msginfo *msginfo;
1474         struct vmbus_channel_message_header *requestheader;
1475         struct vmbus_channel_version_response *version_response;
1476         unsigned long flags;
1477
1478         version_response = (struct vmbus_channel_version_response *)hdr;
1479
1480         trace_vmbus_onversion_response(version_response);
1481
1482         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1483
1484         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1485                                 msglistentry) {
1486                 requestheader =
1487                         (struct vmbus_channel_message_header *)msginfo->msg;
1488
1489                 if (requestheader->msgtype ==
1490                     CHANNELMSG_INITIATE_CONTACT) {
1491                         memcpy(&msginfo->response.version_response,
1492                               version_response,
1493                               sizeof(struct vmbus_channel_version_response));
1494                         complete(&msginfo->waitevent);
1495                 }
1496         }
1497         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1498 }
1499
1500 /* Channel message dispatch table */
1501 const struct vmbus_channel_message_table_entry
1502 channel_message_table[CHANNELMSG_COUNT] = {
1503         { CHANNELMSG_INVALID,                   0, NULL, 0},
1504         { CHANNELMSG_OFFERCHANNEL,              0, vmbus_onoffer,
1505                 sizeof(struct vmbus_channel_offer_channel)},
1506         { CHANNELMSG_RESCIND_CHANNELOFFER,      0, vmbus_onoffer_rescind,
1507                 sizeof(struct vmbus_channel_rescind_offer) },
1508         { CHANNELMSG_REQUESTOFFERS,             0, NULL, 0},
1509         { CHANNELMSG_ALLOFFERS_DELIVERED,       1, vmbus_onoffers_delivered, 0},
1510         { CHANNELMSG_OPENCHANNEL,               0, NULL, 0},
1511         { CHANNELMSG_OPENCHANNEL_RESULT,        1, vmbus_onopen_result,
1512                 sizeof(struct vmbus_channel_open_result)},
1513         { CHANNELMSG_CLOSECHANNEL,              0, NULL, 0},
1514         { CHANNELMSG_GPADL_HEADER,              0, NULL, 0},
1515         { CHANNELMSG_GPADL_BODY,                0, NULL, 0},
1516         { CHANNELMSG_GPADL_CREATED,             1, vmbus_ongpadl_created,
1517                 sizeof(struct vmbus_channel_gpadl_created)},
1518         { CHANNELMSG_GPADL_TEARDOWN,            0, NULL, 0},
1519         { CHANNELMSG_GPADL_TORNDOWN,            1, vmbus_ongpadl_torndown,
1520                 sizeof(struct vmbus_channel_gpadl_torndown) },
1521         { CHANNELMSG_RELID_RELEASED,            0, NULL, 0},
1522         { CHANNELMSG_INITIATE_CONTACT,          0, NULL, 0},
1523         { CHANNELMSG_VERSION_RESPONSE,          1, vmbus_onversion_response,
1524                 sizeof(struct vmbus_channel_version_response)},
1525         { CHANNELMSG_UNLOAD,                    0, NULL, 0},
1526         { CHANNELMSG_UNLOAD_RESPONSE,           1, vmbus_unload_response, 0},
1527         { CHANNELMSG_18,                        0, NULL, 0},
1528         { CHANNELMSG_19,                        0, NULL, 0},
1529         { CHANNELMSG_20,                        0, NULL, 0},
1530         { CHANNELMSG_TL_CONNECT_REQUEST,        0, NULL, 0},
1531         { CHANNELMSG_MODIFYCHANNEL,             0, NULL, 0},
1532         { CHANNELMSG_TL_CONNECT_RESULT,         0, NULL, 0},
1533         { CHANNELMSG_MODIFYCHANNEL_RESPONSE,    1, vmbus_onmodifychannel_response,
1534                 sizeof(struct vmbus_channel_modifychannel_response)},
1535 };
1536
1537 /*
1538  * vmbus_onmessage - Handler for channel protocol messages.
1539  *
1540  * This is invoked in the vmbus worker thread context.
1541  */
1542 void vmbus_onmessage(struct vmbus_channel_message_header *hdr)
1543 {
1544         trace_vmbus_on_message(hdr);
1545
1546         /*
1547          * vmbus_on_msg_dpc() makes sure the hdr->msgtype here can not go
1548          * out of bound and the message_handler pointer can not be NULL.
1549          */
1550         channel_message_table[hdr->msgtype].message_handler(hdr);
1551 }
1552
1553 /*
1554  * vmbus_request_offers - Send a request to get all our pending offers.
1555  */
1556 int vmbus_request_offers(void)
1557 {
1558         struct vmbus_channel_message_header *msg;
1559         struct vmbus_channel_msginfo *msginfo;
1560         int ret;
1561
1562         msginfo = kzalloc(sizeof(*msginfo) +
1563                           sizeof(struct vmbus_channel_message_header),
1564                           GFP_KERNEL);
1565         if (!msginfo)
1566                 return -ENOMEM;
1567
1568         msg = (struct vmbus_channel_message_header *)msginfo->msg;
1569
1570         msg->msgtype = CHANNELMSG_REQUESTOFFERS;
1571
1572         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_message_header),
1573                              true);
1574
1575         trace_vmbus_request_offers(ret);
1576
1577         if (ret != 0) {
1578                 pr_err("Unable to request offers - %d\n", ret);
1579
1580                 goto cleanup;
1581         }
1582
1583 cleanup:
1584         kfree(msginfo);
1585
1586         return ret;
1587 }
1588
1589 void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
1590                                 void (*sc_cr_cb)(struct vmbus_channel *new_sc))
1591 {
1592         primary_channel->sc_creation_callback = sc_cr_cb;
1593 }
1594 EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
1595
1596 void vmbus_set_chn_rescind_callback(struct vmbus_channel *channel,
1597                 void (*chn_rescind_cb)(struct vmbus_channel *))
1598 {
1599         channel->chn_rescind_callback = chn_rescind_cb;
1600 }
1601 EXPORT_SYMBOL_GPL(vmbus_set_chn_rescind_callback);