sys/dev/hyperv/vmbus/hv_channel_mgmt.c

   1 /*-
   2  * Copyright (c) 2009-2012 Microsoft Corp.
   3  * Copyright (c) 2012 NetApp Inc.
   4  * Copyright (c) 2012 Citrix Inc.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice unmodified, this list of conditions, and the following
  12  *    disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #include <sys/cdefs.h>
  30 __FBSDID("$FreeBSD$");
  31
  32 #include <sys/param.h>
  33 #include <sys/mbuf.h>
  34
  35 #include "hv_vmbus_priv.h"
  36
  37 /*
  38  * Internal functions
  39  */
  40
  41 static void vmbus_channel_on_offer(hv_vmbus_channel_msg_header* hdr);
  42 static void vmbus_channel_on_offer_internal(void* context);
  43 static void vmbus_channel_on_open_result(hv_vmbus_channel_msg_header* hdr);
  44 static void vmbus_channel_on_offer_rescind(hv_vmbus_channel_msg_header* hdr);
  45 static void vmbus_channel_on_offer_rescind_internal(void* context);
  46 static void vmbus_channel_on_gpadl_created(hv_vmbus_channel_msg_header* hdr);
  47 static void vmbus_channel_on_gpadl_torndown(hv_vmbus_channel_msg_header* hdr);
  48 static void vmbus_channel_on_offers_delivered(hv_vmbus_channel_msg_header* hdr);
  49 static void vmbus_channel_on_version_response(hv_vmbus_channel_msg_header* hdr);
  50
  51 /**
  52  * Channel message dispatch table
  53  */
  54 hv_vmbus_channel_msg_table_entry
  55     g_channel_message_table[HV_CHANNEL_MESSAGE_COUNT] = {
  56         { HV_CHANNEL_MESSAGE_INVALID,
  57                 NULL },
  58         { HV_CHANNEL_MESSAGE_OFFER_CHANNEL,
  59                 vmbus_channel_on_offer },
  60         { HV_CHANNEL_MESSAGE_RESCIND_CHANNEL_OFFER,
  61                 vmbus_channel_on_offer_rescind },
  62         { HV_CHANNEL_MESSAGE_REQUEST_OFFERS,
  63                 NULL },
  64         { HV_CHANNEL_MESSAGE_ALL_OFFERS_DELIVERED,
  65                 vmbus_channel_on_offers_delivered },
  66         { HV_CHANNEL_MESSAGE_OPEN_CHANNEL,
  67                 NULL },
  68         { HV_CHANNEL_MESSAGE_OPEN_CHANNEL_RESULT,
  69                 vmbus_channel_on_open_result },
  70         { HV_CHANNEL_MESSAGE_CLOSE_CHANNEL,
  71                 NULL },
  72         { HV_CHANNEL_MESSAGEL_GPADL_HEADER,
  73                 NULL },
  74         { HV_CHANNEL_MESSAGE_GPADL_BODY,
  75                 NULL },
  76         { HV_CHANNEL_MESSAGE_GPADL_CREATED,
  77                 vmbus_channel_on_gpadl_created },
  78         { HV_CHANNEL_MESSAGE_GPADL_TEARDOWN,
  79                 NULL },
  80         { HV_CHANNEL_MESSAGE_GPADL_TORNDOWN,
  81                 vmbus_channel_on_gpadl_torndown },
  82         { HV_CHANNEL_MESSAGE_REL_ID_RELEASED,
  83                 NULL },
  84         { HV_CHANNEL_MESSAGE_INITIATED_CONTACT,
  85                 NULL },
  86         { HV_CHANNEL_MESSAGE_VERSION_RESPONSE,
  87                 vmbus_channel_on_version_response },
  88         { HV_CHANNEL_MESSAGE_UNLOAD,
  89                 NULL }
  90 };
  91
  92 typedef struct hv_work_item {
  93         struct task     work;
  94         void            (*callback)(void *);
  95         void*           context;
  96 } hv_work_item;
  97
  98 /**
  99  * Implementation of the work abstraction.
 100  */
 101 static void
 102 work_item_callback(void *work, int pending)
 103 {
 104         struct hv_work_item *w = (struct hv_work_item *)work;
 105
 106         w->callback(w->context);
 107
 108         free(w, M_DEVBUF);
 109 }
 110
 111 /**
 112  * @brief Create work item
 113  */
 114 static int
 115 hv_queue_work_item(
 116         void (*callback)(void *), void *context)
 117 {
 118         struct hv_work_item *w = malloc(sizeof(struct hv_work_item),
 119                                         M_DEVBUF, M_NOWAIT);
 120         KASSERT(w != NULL, ("Error VMBUS: Failed to allocate WorkItem\n"));
 121         if (w == NULL)
 122             return (ENOMEM);
 123
 124         w->callback = callback;
 125         w->context = context;
 126
 127         TASK_INIT(&w->work, 0, work_item_callback, w);
 128
 129         return (taskqueue_enqueue(taskqueue_thread, &w->work));
 130 }
 131
 132
 133 /**
 134  * @brief Allocate and initialize a vmbus channel object
 135  */
 136 hv_vmbus_channel*
 137 hv_vmbus_allocate_channel(void)
 138 {
 139         hv_vmbus_channel* channel;
 140
 141         channel = (hv_vmbus_channel*) malloc(
 142                                         sizeof(hv_vmbus_channel),
 143                                         M_DEVBUF,
 144                                         M_WAITOK | M_ZERO);
 145
 146         mtx_init(&channel->sc_lock, "vmbus multi channel", NULL, MTX_DEF);
 147         TAILQ_INIT(&channel->sc_list_anchor);
 148
 149         return (channel);
 150 }
 151
 152 /**
 153  * @brief Release the resources used by the vmbus channel object
 154  */
 155 void
 156 hv_vmbus_free_vmbus_channel(hv_vmbus_channel* channel)
 157 {
 158         mtx_destroy(&channel->sc_lock);
 159         free(channel, M_DEVBUF);
 160 }
 161
 162 /**
 163  * @brief Process the offer by creating a channel/device
 164  * associated with this offer
 165  */
 166 static void
 167 vmbus_channel_process_offer(hv_vmbus_channel *new_channel)
 168 {
 169         boolean_t               f_new;
 170         hv_vmbus_channel*       channel;
 171         int                     ret;
 172         uint32_t                relid;
 173
 174         f_new = TRUE;
 175         channel = NULL;
 176         relid = new_channel->offer_msg.child_rel_id;
 177         /*
 178          * Make sure this is a new offer
 179          */
 180         mtx_lock(&hv_vmbus_g_connection.channel_lock);
 181         hv_vmbus_g_connection.channels[relid] = new_channel;
 182
 183         TAILQ_FOREACH(channel, &hv_vmbus_g_connection.channel_anchor,
 184             list_entry)
 185         {
 186                 if (memcmp(&channel->offer_msg.offer.interface_type,
 187                     &new_channel->offer_msg.offer.interface_type,
 188                     sizeof(hv_guid)) == 0 &&
 189                     memcmp(&channel->offer_msg.offer.interface_instance,
 190                     &new_channel->offer_msg.offer.interface_instance,
 191                     sizeof(hv_guid)) == 0) {
 192                         f_new = FALSE;
 193                         break;
 194                 }
 195         }
 196
 197         if (f_new) {
 198                 /* Insert at tail */
 199                 TAILQ_INSERT_TAIL(
 200                     &hv_vmbus_g_connection.channel_anchor,
 201                     new_channel,
 202                     list_entry);
 203         }
 204         mtx_unlock(&hv_vmbus_g_connection.channel_lock);
 205
 206         /*XXX add new channel to percpu_list */
 207
 208         if (!f_new) {
 209                 /*
 210                  * Check if this is a sub channel.
 211                  */
 212                 if (new_channel->offer_msg.offer.sub_channel_index != 0) {
 213                         /*
 214                          * It is a sub channel offer, process it.
 215                          */
 216                         new_channel->primary_channel = channel;
 217                         new_channel->device = channel->device;
 218                         mtx_lock(&channel->sc_lock);
 219                         TAILQ_INSERT_TAIL(
 220                             &channel->sc_list_anchor,
 221                             new_channel,
 222                             sc_list_entry);
 223                         mtx_unlock(&channel->sc_lock);
 224
 225                         /* Insert new channel into channel_anchor. */
 226                         printf("VMBUS get multi-channel offer, rel=%u,sub=%u\n",
 227                             new_channel->offer_msg.child_rel_id,
 228                             new_channel->offer_msg.offer.sub_channel_index);
 229                         mtx_lock(&hv_vmbus_g_connection.channel_lock);
 230                         TAILQ_INSERT_TAIL(&hv_vmbus_g_connection.channel_anchor,
 231                             new_channel, list_entry);
 232                         mtx_unlock(&hv_vmbus_g_connection.channel_lock);
 233
 234                         if(bootverbose)
 235                                 printf("VMBUS: new multi-channel offer <%p>, "
 236                                     "its primary channel is <%p>.\n",
 237                                     new_channel, new_channel->primary_channel);
 238
 239                         /*XXX add it to percpu_list */
 240
 241                         new_channel->state = HV_CHANNEL_OPEN_STATE;
 242                         if (channel->sc_creation_callback != NULL) {
 243                                 channel->sc_creation_callback(new_channel);
 244                         }
 245                         return;
 246                 }
 247
 248             hv_vmbus_free_vmbus_channel(new_channel);
 249             return;
 250         }
 251
 252         new_channel->state = HV_CHANNEL_OPEN_STATE;
 253
 254         /*
 255          * Start the process of binding this offer to the driver
 256          * (We need to set the device field before calling
 257          * hv_vmbus_child_device_add())
 258          */
 259         new_channel->device = hv_vmbus_child_device_create(
 260             new_channel->offer_msg.offer.interface_type,
 261             new_channel->offer_msg.offer.interface_instance, new_channel);
 262
 263         /*
 264          * Add the new device to the bus. This will kick off device-driver
 265          * binding which eventually invokes the device driver's AddDevice()
 266          * method.
 267          */
 268         ret = hv_vmbus_child_device_register(new_channel->device);
 269         if (ret != 0) {
 270                 mtx_lock(&hv_vmbus_g_connection.channel_lock);
 271                 TAILQ_REMOVE(
 272                     &hv_vmbus_g_connection.channel_anchor,
 273                     new_channel,
 274                     list_entry);
 275                 mtx_unlock(&hv_vmbus_g_connection.channel_lock);
 276                 hv_vmbus_free_vmbus_channel(new_channel);
 277         }
 278 }
 279
 280 /**
 281  * Array of device guids that are performance critical. We try to distribute
 282  * the interrupt load for these devices across all online cpus.
 283  */
 284 static const hv_guid high_perf_devices[] = {
 285         {HV_NIC_GUID, },
 286         {HV_IDE_GUID, },
 287         {HV_SCSI_GUID, },
 288 };
 289
 290 enum {
 291         PERF_CHN_NIC = 0,
 292         PERF_CHN_IDE,
 293         PERF_CHN_SCSI,
 294         MAX_PERF_CHN,
 295 };
 296
 297 /*
 298  * We use this static number to distribute the channel interrupt load.
 299  */
 300 static uint32_t next_vcpu;
 301
 302 /**
 303  * Starting with Win8, we can statically distribute the incoming
 304  * channel interrupt load by binding a channel to VCPU. We
 305  * implement here a simple round robin scheme for distributing
 306  * the interrupt load.
 307  * We will bind channels that are not performance critical to cpu 0 and
 308  * performance critical channels (IDE, SCSI and Network) will be uniformly
 309  * distributed across all available CPUs.
 310  */
 311 static void
 312 vmbus_channel_select_cpu(hv_vmbus_channel *channel, hv_guid *guid)
 313 {
 314         uint32_t current_cpu;
 315         int i;
 316         boolean_t is_perf_channel = FALSE;
 317
 318         for (i = PERF_CHN_NIC; i < MAX_PERF_CHN; i++) {
 319                 if (memcmp(guid->data, high_perf_devices[i].data,
 320                     sizeof(hv_guid)) == 0) {
 321                         is_perf_channel = TRUE;
 322                         break;
 323                 }
 324         }
 325
 326         if ((hv_vmbus_protocal_version == HV_VMBUS_VERSION_WS2008) ||
 327             (hv_vmbus_protocal_version == HV_VMBUS_VERSION_WIN7) ||
 328             (!is_perf_channel)) {
 329                 /* Host's view of guest cpu */
 330                 channel->target_vcpu = 0;
 331                 /* Guest's own view of cpu */
 332                 channel->target_cpu = 0;
 333                 return;
 334         }
 335         /* mp_ncpus should have the number cpus currently online */
 336         current_cpu = (++next_vcpu % mp_ncpus);
 337         channel->target_cpu = current_cpu;
 338         channel->target_vcpu =
 339             hv_vmbus_g_context.hv_vcpu_index[current_cpu];
 340         if (bootverbose)
 341                 printf("VMBUS: Total online cpus %d, assign perf channel %d "
 342                     "to vcpu %d, cpu %d\n", mp_ncpus, i, channel->target_vcpu,
 343                     current_cpu);
 344 }
 345
 346 /**
 347  * @brief Handler for channel offers from Hyper-V/Azure
 348  *
 349  * Handler for channel offers from vmbus in parent partition. We ignore
 350  * all offers except network and storage offers. For each network and storage
 351  * offers, we create a channel object and queue a work item to the channel
 352  * object to process the offer synchronously
 353  */
 354 static void
 355 vmbus_channel_on_offer(hv_vmbus_channel_msg_header* hdr)
 356 {
 357         hv_vmbus_channel_offer_channel* offer;
 358         hv_vmbus_channel_offer_channel* copied;
 359
 360         offer = (hv_vmbus_channel_offer_channel*) hdr;
 361
 362         hv_guid *guidType;
 363         hv_guid *guidInstance;
 364
 365         guidType = &offer->offer.interface_type;
 366         guidInstance = &offer->offer.interface_instance;
 367
 368         // copy offer data
 369         copied = malloc(sizeof(*copied), M_DEVBUF, M_NOWAIT);
 370         if (copied == NULL) {
 371                 printf("fail to allocate memory\n");
 372                 return;
 373         }
 374
 375         memcpy(copied, hdr, sizeof(*copied));
 376         hv_queue_work_item(vmbus_channel_on_offer_internal, copied);
 377 }
 378
 379 static void
 380 vmbus_channel_on_offer_internal(void* context)
 381 {
 382         hv_vmbus_channel* new_channel;
 383
 384         hv_vmbus_channel_offer_channel* offer = (hv_vmbus_channel_offer_channel*)context;
 385         /* Allocate the channel object and save this offer */
 386         new_channel = hv_vmbus_allocate_channel();
 387
 388         /*
 389          * By default we setup state to enable batched
 390          * reading. A specific service can choose to
 391          * disable this prior to opening the channel.
 392          */
 393         new_channel->batched_reading = TRUE;
 394
 395         new_channel->signal_event_param =
 396             (hv_vmbus_input_signal_event *)
 397             (HV_ALIGN_UP((unsigned long)
 398                 &new_channel->signal_event_buffer,
 399                 HV_HYPERCALL_PARAM_ALIGN));
 400
 401         new_channel->signal_event_param->connection_id.as_uint32_t = 0;
 402         new_channel->signal_event_param->connection_id.u.id =
 403             HV_VMBUS_EVENT_CONNECTION_ID;
 404         new_channel->signal_event_param->flag_number = 0;
 405         new_channel->signal_event_param->rsvd_z = 0;
 406
 407         if (hv_vmbus_protocal_version != HV_VMBUS_VERSION_WS2008) {
 408                 new_channel->is_dedicated_interrupt =
 409                     (offer->is_dedicated_interrupt != 0);
 410                 new_channel->signal_event_param->connection_id.u.id =
 411                     offer->connection_id;
 412         }
 413
 414         /*
 415          * Bind the channel to a chosen cpu.
 416          */
 417         vmbus_channel_select_cpu(new_channel,
 418             &offer->offer.interface_type);
 419
 420         memcpy(&new_channel->offer_msg, offer,
 421             sizeof(hv_vmbus_channel_offer_channel));
 422         new_channel->monitor_group = (uint8_t) offer->monitor_id / 32;
 423         new_channel->monitor_bit = (uint8_t) offer->monitor_id % 32;
 424
 425         vmbus_channel_process_offer(new_channel);
 426
 427         free(offer, M_DEVBUF);
 428 }
 429
 430 /**
 431  * @brief Rescind offer handler.
 432  *
 433  * We queue a work item to process this offer
 434  * synchronously
 435  */
 436 static void
 437 vmbus_channel_on_offer_rescind(hv_vmbus_channel_msg_header* hdr)
 438 {
 439         hv_vmbus_channel_rescind_offer* rescind;
 440         hv_vmbus_channel*               channel;
 441
 442         rescind = (hv_vmbus_channel_rescind_offer*) hdr;
 443
 444         channel = hv_vmbus_g_connection.channels[rescind->child_rel_id];
 445         if (channel == NULL)
 446             return;
 447
 448         hv_queue_work_item(vmbus_channel_on_offer_rescind_internal, channel);
 449         hv_vmbus_g_connection.channels[rescind->child_rel_id] = NULL;
 450 }
 451
 452 static void
 453 vmbus_channel_on_offer_rescind_internal(void *context)
 454 {
 455         hv_vmbus_channel*               channel;
 456
 457         channel = (hv_vmbus_channel*)context;
 458         if (HV_VMBUS_CHAN_ISPRIMARY(channel)) {
 459                 /* Only primary channel owns the hv_device */
 460                 hv_vmbus_child_device_unregister(channel->device);
 461         }
 462 }
 463
 464 /**
 465  *
 466  * @brief Invoked when all offers have been delivered.
 467  */
 468 static void
 469 vmbus_channel_on_offers_delivered(hv_vmbus_channel_msg_header* hdr)
 470 {
 471 }
 472
 473 /**
 474  * @brief Open result handler.
 475  *
 476  * This is invoked when we received a response
 477  * to our channel open request. Find the matching request, copy the
 478  * response and signal the requesting thread.
 479  */
 480 static void
 481 vmbus_channel_on_open_result(hv_vmbus_channel_msg_header* hdr)
 482 {
 483         hv_vmbus_channel_open_result*   result;
 484         hv_vmbus_channel_msg_info*      msg_info;
 485         hv_vmbus_channel_msg_header*    requestHeader;
 486         hv_vmbus_channel_open_channel*  openMsg;
 487
 488         result = (hv_vmbus_channel_open_result*) hdr;
 489
 490         /*
 491          * Find the open msg, copy the result and signal/unblock the wait event
 492          */
 493         mtx_lock_spin(&hv_vmbus_g_connection.channel_msg_lock);
 494
 495         TAILQ_FOREACH(msg_info, &hv_vmbus_g_connection.channel_msg_anchor,
 496             msg_list_entry) {
 497             requestHeader = (hv_vmbus_channel_msg_header*) msg_info->msg;
 498
 499             if (requestHeader->message_type ==
 500                     HV_CHANNEL_MESSAGE_OPEN_CHANNEL) {
 501                 openMsg = (hv_vmbus_channel_open_channel*) msg_info->msg;
 502                 if (openMsg->child_rel_id == result->child_rel_id
 503                     && openMsg->open_id == result->open_id) {
 504                     memcpy(&msg_info->response.open_result, result,
 505                         sizeof(hv_vmbus_channel_open_result));
 506                     sema_post(&msg_info->wait_sema);
 507                     break;
 508                 }
 509             }
 510         }
 511         mtx_unlock_spin(&hv_vmbus_g_connection.channel_msg_lock);
 512
 513 }
 514
 515 /**
 516  * @brief GPADL created handler.
 517  *
 518  * This is invoked when we received a response
 519  * to our gpadl create request. Find the matching request, copy the
 520  * response and signal the requesting thread.
 521  */
 522 static void
 523 vmbus_channel_on_gpadl_created(hv_vmbus_channel_msg_header* hdr)
 524 {
 525         hv_vmbus_channel_gpadl_created*         gpadl_created;
 526         hv_vmbus_channel_msg_info*              msg_info;
 527         hv_vmbus_channel_msg_header*            request_header;
 528         hv_vmbus_channel_gpadl_header*          gpadl_header;
 529
 530         gpadl_created = (hv_vmbus_channel_gpadl_created*) hdr;
 531
 532         /* Find the establish msg, copy the result and signal/unblock
 533          * the wait event
 534          */
 535         mtx_lock_spin(&hv_vmbus_g_connection.channel_msg_lock);
 536         TAILQ_FOREACH(msg_info, &hv_vmbus_g_connection.channel_msg_anchor,
 537                 msg_list_entry) {
 538             request_header = (hv_vmbus_channel_msg_header*) msg_info->msg;
 539             if (request_header->message_type ==
 540                     HV_CHANNEL_MESSAGEL_GPADL_HEADER) {
 541                 gpadl_header =
 542                     (hv_vmbus_channel_gpadl_header*) request_header;
 543
 544                 if ((gpadl_created->child_rel_id == gpadl_header->child_rel_id)
 545                     && (gpadl_created->gpadl == gpadl_header->gpadl)) {
 546                     memcpy(&msg_info->response.gpadl_created,
 547                         gpadl_created,
 548                         sizeof(hv_vmbus_channel_gpadl_created));
 549                     sema_post(&msg_info->wait_sema);
 550                     break;
 551                 }
 552             }
 553         }
 554         mtx_unlock_spin(&hv_vmbus_g_connection.channel_msg_lock);
 555 }
 556
 557 /**
 558  * @brief GPADL torndown handler.
 559  *
 560  * This is invoked when we received a respons
 561  * to our gpadl teardown request. Find the matching request, copy the
 562  * response and signal the requesting thread
 563  */
 564 static void
 565 vmbus_channel_on_gpadl_torndown(hv_vmbus_channel_msg_header* hdr)
 566 {
 567         hv_vmbus_channel_gpadl_torndown*        gpadl_torndown;
 568         hv_vmbus_channel_msg_info*              msg_info;
 569         hv_vmbus_channel_msg_header*            requestHeader;
 570         hv_vmbus_channel_gpadl_teardown*        gpadlTeardown;
 571
 572         gpadl_torndown = (hv_vmbus_channel_gpadl_torndown*)hdr;
 573
 574         /*
 575          * Find the open msg, copy the result and signal/unblock the
 576          * wait event.
 577          */
 578
 579         mtx_lock_spin(&hv_vmbus_g_connection.channel_msg_lock);
 580
 581         TAILQ_FOREACH(msg_info, &hv_vmbus_g_connection.channel_msg_anchor,
 582                 msg_list_entry) {
 583             requestHeader = (hv_vmbus_channel_msg_header*) msg_info->msg;
 584
 585             if (requestHeader->message_type
 586                     == HV_CHANNEL_MESSAGE_GPADL_TEARDOWN) {
 587                 gpadlTeardown =
 588                     (hv_vmbus_channel_gpadl_teardown*) requestHeader;
 589
 590                 if (gpadl_torndown->gpadl == gpadlTeardown->gpadl) {
 591                     memcpy(&msg_info->response.gpadl_torndown,
 592                         gpadl_torndown,
 593                         sizeof(hv_vmbus_channel_gpadl_torndown));
 594                     sema_post(&msg_info->wait_sema);
 595                     break;
 596                 }
 597             }
 598         }
 599     mtx_unlock_spin(&hv_vmbus_g_connection.channel_msg_lock);
 600 }
 601
 602 /**
 603  * @brief Version response handler.
 604  *
 605  * This is invoked when we received a response
 606  * to our initiate contact request. Find the matching request, copy th
 607  * response and signal the requesting thread.
 608  */
 609 static void
 610 vmbus_channel_on_version_response(hv_vmbus_channel_msg_header* hdr)
 611 {
 612         hv_vmbus_channel_msg_info*              msg_info;
 613         hv_vmbus_channel_msg_header*            requestHeader;
 614         hv_vmbus_channel_initiate_contact*      initiate;
 615         hv_vmbus_channel_version_response*      versionResponse;
 616
 617         versionResponse = (hv_vmbus_channel_version_response*)hdr;
 618
 619         mtx_lock_spin(&hv_vmbus_g_connection.channel_msg_lock);
 620         TAILQ_FOREACH(msg_info, &hv_vmbus_g_connection.channel_msg_anchor,
 621             msg_list_entry) {
 622             requestHeader = (hv_vmbus_channel_msg_header*) msg_info->msg;
 623             if (requestHeader->message_type
 624                 == HV_CHANNEL_MESSAGE_INITIATED_CONTACT) {
 625                 initiate =
 626                     (hv_vmbus_channel_initiate_contact*) requestHeader;
 627                 memcpy(&msg_info->response.version_response,
 628                     versionResponse,
 629                     sizeof(hv_vmbus_channel_version_response));
 630                 sema_post(&msg_info->wait_sema);
 631             }
 632         }
 633     mtx_unlock_spin(&hv_vmbus_g_connection.channel_msg_lock);
 634
 635 }
 636
 637 /**
 638  *  @brief Send a request to get all our pending offers.
 639  */
 640 int
 641 hv_vmbus_request_channel_offers(void)
 642 {
 643         int                             ret;
 644         hv_vmbus_channel_msg_header*    msg;
 645         hv_vmbus_channel_msg_info*      msg_info;
 646
 647         msg_info = (hv_vmbus_channel_msg_info *)
 648             malloc(sizeof(hv_vmbus_channel_msg_info)
 649                     + sizeof(hv_vmbus_channel_msg_header), M_DEVBUF, M_NOWAIT);
 650
 651         if (msg_info == NULL) {
 652             if(bootverbose)
 653                 printf("Error VMBUS: malloc failed for Request Offers\n");
 654             return (ENOMEM);
 655         }
 656
 657         msg = (hv_vmbus_channel_msg_header*) msg_info->msg;
 658         msg->message_type = HV_CHANNEL_MESSAGE_REQUEST_OFFERS;
 659
 660         ret = hv_vmbus_post_message(msg, sizeof(hv_vmbus_channel_msg_header));
 661
 662         free(msg_info, M_DEVBUF);
 663
 664         return (ret);
 665 }
 666
 667 /**
 668  * @brief Release channels that are unattached/unconnected (i.e., no drivers associated)
 669  */
 670 void
 671 hv_vmbus_release_unattached_channels(void)
 672 {
 673         hv_vmbus_channel *channel;
 674
 675         mtx_lock(&hv_vmbus_g_connection.channel_lock);
 676
 677         while (!TAILQ_EMPTY(&hv_vmbus_g_connection.channel_anchor)) {
 678             channel = TAILQ_FIRST(&hv_vmbus_g_connection.channel_anchor);
 679             TAILQ_REMOVE(&hv_vmbus_g_connection.channel_anchor,
 680                             channel, list_entry);
 681
 682             if (HV_VMBUS_CHAN_ISPRIMARY(channel)) {
 683                 /* Only primary channel owns the hv_device */
 684                 hv_vmbus_child_device_unregister(channel->device);
 685             }
 686             hv_vmbus_free_vmbus_channel(channel);
 687         }
 688         bzero(hv_vmbus_g_connection.channels,
 689                 sizeof(hv_vmbus_channel*) * HV_CHANNEL_MAX_COUNT);
 690         mtx_unlock(&hv_vmbus_g_connection.channel_lock);
 691 }
 692
 693 /**
 694  * @brief Select the best outgoing channel
 695  *
 696  * The channel whose vcpu binding is closest to the currect vcpu will
 697  * be selected.
 698  * If no multi-channel, always select primary channel
 699  *
 700  * @param primary - primary channel
 701  */
 702 struct hv_vmbus_channel *
 703 vmbus_select_outgoing_channel(struct hv_vmbus_channel *primary)
 704 {
 705         hv_vmbus_channel *new_channel = NULL;
 706         hv_vmbus_channel *outgoing_channel = primary;
 707         int old_cpu_distance = 0;
 708         int new_cpu_distance = 0;
 709         int cur_vcpu = 0;
 710         int smp_pro_id = PCPU_GET(cpuid);
 711
 712         if (TAILQ_EMPTY(&primary->sc_list_anchor)) {
 713                 return outgoing_channel;
 714         }
 715
 716         if (smp_pro_id >= MAXCPU) {
 717                 return outgoing_channel;
 718         }
 719
 720         cur_vcpu = hv_vmbus_g_context.hv_vcpu_index[smp_pro_id];
 721
 722         TAILQ_FOREACH(new_channel, &primary->sc_list_anchor, sc_list_entry) {
 723                 if (new_channel->state != HV_CHANNEL_OPENED_STATE){
 724                         continue;
 725                 }
 726
 727                 if (new_channel->target_vcpu == cur_vcpu){
 728                         return new_channel;
 729                 }
 730
 731                 old_cpu_distance = ((outgoing_channel->target_vcpu > cur_vcpu) ?
 732                     (outgoing_channel->target_vcpu - cur_vcpu) :
 733                     (cur_vcpu - outgoing_channel->target_vcpu));
 734
 735                 new_cpu_distance = ((new_channel->target_vcpu > cur_vcpu) ?
 736                     (new_channel->target_vcpu - cur_vcpu) :
 737                     (cur_vcpu - new_channel->target_vcpu));
 738
 739                 if (old_cpu_distance < new_cpu_distance) {
 740                         continue;
 741                 }
 742
 743                 outgoing_channel = new_channel;
 744         }
 745
 746         return(outgoing_channel);
 747 }