drivers/hv/channel_mgmt.c

   1 /*
   2  * Copyright (c) 2009, Microsoft Corporation.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms and conditions of the GNU General Public License,
   6  * version 2, as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  15  * Place - Suite 330, Boston, MA 02111-1307 USA.
  16  *
  17  * Authors:
  18  *   Haiyang Zhang <haiyangz@microsoft.com>
  19  *   Hank Janssen  <hjanssen@microsoft.com>
  20  */
  21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  22
  23 #include <linux/kernel.h>
  24 #include <linux/sched.h>
  25 #include <linux/wait.h>
  26 #include <linux/mm.h>
  27 #include <linux/slab.h>
  28 #include <linux/list.h>
  29 #include <linux/module.h>
  30 #include <linux/completion.h>
  31 #include <linux/hyperv.h>
  32
  33 #include "hyperv_vmbus.h"
  34
  35 struct vmbus_channel_message_table_entry {
  36         enum vmbus_channel_message_type message_type;
  37         void (*message_handler)(struct vmbus_channel_message_header *msg);
  38 };
  39
  40
  41 /**
  42  * vmbus_prep_negotiate_resp() - Create default response for Hyper-V Negotiate message
  43  * @icmsghdrp: Pointer to msg header structure
  44  * @icmsg_negotiate: Pointer to negotiate message structure
  45  * @buf: Raw buffer channel data
  46  *
  47  * @icmsghdrp is of type &struct icmsg_hdr.
  48  * @negop is of type &struct icmsg_negotiate.
  49  * Set up and fill in default negotiate response message.
  50  *
  51  * The max_fw_version specifies the maximum framework version that
  52  * we can support and max _srv_version specifies the maximum service
  53  * version we can support. A special value MAX_SRV_VER can be
  54  * specified to indicate that we can handle the maximum version
  55  * exposed by the host.
  56  *
  57  * Mainly used by Hyper-V drivers.
  58  */
  59 void vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
  60                                 struct icmsg_negotiate *negop, u8 *buf,
  61                                 int max_fw_version, int max_srv_version)
  62 {
  63         int icframe_vercnt;
  64         int icmsg_vercnt;
  65         int i;
  66
  67         icmsghdrp->icmsgsize = 0x10;
  68
  69         negop = (struct icmsg_negotiate *)&buf[
  70                 sizeof(struct vmbuspipe_hdr) +
  71                 sizeof(struct icmsg_hdr)];
  72
  73         icframe_vercnt = negop->icframe_vercnt;
  74         icmsg_vercnt = negop->icmsg_vercnt;
  75
  76         /*
  77          * Select the framework version number we will
  78          * support.
  79          */
  80
  81         for (i = 0; i < negop->icframe_vercnt; i++) {
  82                 if (negop->icversion_data[i].major <= max_fw_version)
  83                         icframe_vercnt = negop->icversion_data[i].major;
  84         }
  85
  86         for (i = negop->icframe_vercnt;
  87                  (i < negop->icframe_vercnt + negop->icmsg_vercnt); i++) {
  88                 if (negop->icversion_data[i].major <= max_srv_version)
  89                         icmsg_vercnt = negop->icversion_data[i].major;
  90         }
  91
  92         /*
  93          * Respond with the maximum framework and service
  94          * version numbers we can support.
  95          */
  96         negop->icframe_vercnt = 1;
  97         negop->icmsg_vercnt = 1;
  98         negop->icversion_data[0].major = icframe_vercnt;
  99         negop->icversion_data[0].minor = 0;
 100         negop->icversion_data[1].major = icmsg_vercnt;
 101         negop->icversion_data[1].minor = 0;
 102 }
 103
 104 EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);
 105
 106 /*
 107  * alloc_channel - Allocate and initialize a vmbus channel object
 108  */
 109 static struct vmbus_channel *alloc_channel(void)
 110 {
 111         struct vmbus_channel *channel;
 112
 113         channel = kzalloc(sizeof(*channel), GFP_ATOMIC);
 114         if (!channel)
 115                 return NULL;
 116
 117         spin_lock_init(&channel->inbound_lock);
 118         spin_lock_init(&channel->sc_lock);
 119
 120         INIT_LIST_HEAD(&channel->sc_list);
 121
 122         channel->controlwq = create_workqueue("hv_vmbus_ctl");
 123         if (!channel->controlwq) {
 124                 kfree(channel);
 125                 return NULL;
 126         }
 127
 128         return channel;
 129 }
 130
 131 /*
 132  * release_hannel - Release the vmbus channel object itself
 133  */
 134 static void release_channel(struct work_struct *work)
 135 {
 136         struct vmbus_channel *channel = container_of(work,
 137                                                      struct vmbus_channel,
 138                                                      work);
 139
 140         destroy_workqueue(channel->controlwq);
 141
 142         kfree(channel);
 143 }
 144
 145 /*
 146  * free_channel - Release the resources used by the vmbus channel object
 147  */
 148 static void free_channel(struct vmbus_channel *channel)
 149 {
 150
 151         /*
 152          * We have to release the channel's workqueue/thread in the vmbus's
 153          * workqueue/thread context
 154          * ie we can't destroy ourselves.
 155          */
 156         INIT_WORK(&channel->work, release_channel);
 157         queue_work(vmbus_connection.work_queue, &channel->work);
 158 }
 159
 160
 161
 162 /*
 163  * vmbus_process_rescind_offer -
 164  * Rescind the offer by initiating a device removal
 165  */
 166 static void vmbus_process_rescind_offer(struct work_struct *work)
 167 {
 168         struct vmbus_channel *channel = container_of(work,
 169                                                      struct vmbus_channel,
 170                                                      work);
 171         unsigned long flags;
 172         struct vmbus_channel *primary_channel;
 173         struct vmbus_channel_relid_released msg;
 174
 175         vmbus_device_unregister(channel->device_obj);
 176         memset(&msg, 0, sizeof(struct vmbus_channel_relid_released));
 177         msg.child_relid = channel->offermsg.child_relid;
 178         msg.header.msgtype = CHANNELMSG_RELID_RELEASED;
 179         vmbus_post_msg(&msg, sizeof(struct vmbus_channel_relid_released));
 180
 181         if (channel->primary_channel == NULL) {
 182                 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 183                 list_del(&channel->listentry);
 184                 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 185         } else {
 186                 primary_channel = channel->primary_channel;
 187                 spin_lock_irqsave(&primary_channel->sc_lock, flags);
 188                 list_del(&channel->listentry);
 189                 spin_unlock_irqrestore(&primary_channel->sc_lock, flags);
 190         }
 191         free_channel(channel);
 192 }
 193
 194 void vmbus_free_channels(void)
 195 {
 196         struct vmbus_channel *channel;
 197
 198         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 199                 vmbus_device_unregister(channel->device_obj);
 200                 kfree(channel->device_obj);
 201                 free_channel(channel);
 202         }
 203 }
 204
 205 /*
 206  * vmbus_process_offer - Process the offer by creating a channel/device
 207  * associated with this offer
 208  */
 209 static void vmbus_process_offer(struct work_struct *work)
 210 {
 211         struct vmbus_channel *newchannel = container_of(work,
 212                                                         struct vmbus_channel,
 213                                                         work);
 214         struct vmbus_channel *channel;
 215         bool fnew = true;
 216         int ret;
 217         unsigned long flags;
 218
 219         /* The next possible work is rescind handling */
 220         INIT_WORK(&newchannel->work, vmbus_process_rescind_offer);
 221
 222         /* Make sure this is a new offer */
 223         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 224
 225         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 226                 if (!uuid_le_cmp(channel->offermsg.offer.if_type,
 227                         newchannel->offermsg.offer.if_type) &&
 228                         !uuid_le_cmp(channel->offermsg.offer.if_instance,
 229                                 newchannel->offermsg.offer.if_instance)) {
 230                         fnew = false;
 231                         break;
 232                 }
 233         }
 234
 235         if (fnew)
 236                 list_add_tail(&newchannel->listentry,
 237                               &vmbus_connection.chn_list);
 238
 239         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 240
 241         if (!fnew) {
 242                 /*
 243                  * Check to see if this is a sub-channel.
 244                  */
 245                 if (newchannel->offermsg.offer.sub_channel_index != 0) {
 246                         /*
 247                          * Process the sub-channel.
 248                          */
 249                         newchannel->primary_channel = channel;
 250                         spin_lock_irqsave(&channel->sc_lock, flags);
 251                         list_add_tail(&newchannel->sc_list, &channel->sc_list);
 252                         spin_unlock_irqrestore(&channel->sc_lock, flags);
 253                         newchannel->state = CHANNEL_OPEN_STATE;
 254                         if (channel->sc_creation_callback != NULL)
 255                                 channel->sc_creation_callback(newchannel);
 256
 257                         return;
 258                 }
 259
 260                 free_channel(newchannel);
 261                 return;
 262         }
 263
 264         /*
 265          * Start the process of binding this offer to the driver
 266          * We need to set the DeviceObject field before calling
 267          * vmbus_child_dev_add()
 268          */
 269         newchannel->device_obj = vmbus_device_create(
 270                 &newchannel->offermsg.offer.if_type,
 271                 &newchannel->offermsg.offer.if_instance,
 272                 newchannel);
 273
 274         /*
 275          * Add the new device to the bus. This will kick off device-driver
 276          * binding which eventually invokes the device driver's AddDevice()
 277          * method.
 278          */
 279         ret = vmbus_device_register(newchannel->device_obj);
 280         if (ret != 0) {
 281                 pr_err("unable to add child device object (relid %d)\n",
 282                            newchannel->offermsg.child_relid);
 283
 284                 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 285                 list_del(&newchannel->listentry);
 286                 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 287                 kfree(newchannel->device_obj);
 288
 289                 free_channel(newchannel);
 290         } else {
 291                 /*
 292                  * This state is used to indicate a successful open
 293                  * so that when we do close the channel normally, we
 294                  * can cleanup properly
 295                  */
 296                 newchannel->state = CHANNEL_OPEN_STATE;
 297         }
 298 }
 299
 300 enum {
 301         IDE = 0,
 302         SCSI,
 303         NIC,
 304         MAX_PERF_CHN,
 305 };
 306
 307 /*
 308  * This is an array of device_ids (device types) that are performance critical.
 309  * We attempt to distribute the interrupt load for these devices across
 310  * all available CPUs.
 311  */
 312 static const struct hv_vmbus_device_id hp_devs[] = {
 313         /* IDE */
 314         { HV_IDE_GUID, },
 315         /* Storage - SCSI */
 316         { HV_SCSI_GUID, },
 317         /* Network */
 318         { HV_NIC_GUID, },
 319 };
 320
 321
 322 /*
 323  * We use this state to statically distribute the channel interrupt load.
 324  */
 325 static u32  next_vp;
 326
 327 /*
 328  * Starting with Win8, we can statically distribute the incoming
 329  * channel interrupt load by binding a channel to VCPU. We
 330  * implement here a simple round robin scheme for distributing
 331  * the interrupt load.
 332  * We will bind channels that are not performance critical to cpu 0 and
 333  * performance critical channels (IDE, SCSI and Network) will be uniformly
 334  * distributed across all available CPUs.
 335  */
 336 static u32 get_vp_index(uuid_le *type_guid)
 337 {
 338         u32 cur_cpu;
 339         int i;
 340         bool perf_chn = false;
 341         u32 max_cpus = num_online_cpus();
 342
 343         for (i = IDE; i < MAX_PERF_CHN; i++) {
 344                 if (!memcmp(type_guid->b, hp_devs[i].guid,
 345                                  sizeof(uuid_le))) {
 346                         perf_chn = true;
 347                         break;
 348                 }
 349         }
 350         if ((vmbus_proto_version == VERSION_WS2008) ||
 351             (vmbus_proto_version == VERSION_WIN7) || (!perf_chn)) {
 352                 /*
 353                  * Prior to win8, all channel interrupts are
 354                  * delivered on cpu 0.
 355                  * Also if the channel is not a performance critical
 356                  * channel, bind it to cpu 0.
 357                  */
 358                 return 0;
 359         }
 360         cur_cpu = (++next_vp % max_cpus);
 361         return hv_context.vp_index[cur_cpu];
 362 }
 363
 364 /*
 365  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 366  *
 367  */
 368 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 369 {
 370         struct vmbus_channel_offer_channel *offer;
 371         struct vmbus_channel *newchannel;
 372
 373         offer = (struct vmbus_channel_offer_channel *)hdr;
 374
 375         /* Allocate the channel object and save this offer. */
 376         newchannel = alloc_channel();
 377         if (!newchannel) {
 378                 pr_err("Unable to allocate channel object\n");
 379                 return;
 380         }
 381
 382         /*
 383          * By default we setup state to enable batched
 384          * reading. A specific service can choose to
 385          * disable this prior to opening the channel.
 386          */
 387         newchannel->batched_reading = true;
 388
 389         /*
 390          * Setup state for signalling the host.
 391          */
 392         newchannel->sig_event = (struct hv_input_signal_event *)
 393                                 (ALIGN((unsigned long)
 394                                 &newchannel->sig_buf,
 395                                 HV_HYPERCALL_PARAM_ALIGN));
 396
 397         newchannel->sig_event->connectionid.asu32 = 0;
 398         newchannel->sig_event->connectionid.u.id = VMBUS_EVENT_CONNECTION_ID;
 399         newchannel->sig_event->flag_number = 0;
 400         newchannel->sig_event->rsvdz = 0;
 401
 402         if (vmbus_proto_version != VERSION_WS2008) {
 403                 newchannel->is_dedicated_interrupt =
 404                                 (offer->is_dedicated_interrupt != 0);
 405                 newchannel->sig_event->connectionid.u.id =
 406                                 offer->connection_id;
 407         }
 408
 409         newchannel->target_vp = get_vp_index(&offer->offer.if_type);
 410
 411         memcpy(&newchannel->offermsg, offer,
 412                sizeof(struct vmbus_channel_offer_channel));
 413         newchannel->monitor_grp = (u8)offer->monitorid / 32;
 414         newchannel->monitor_bit = (u8)offer->monitorid % 32;
 415
 416         INIT_WORK(&newchannel->work, vmbus_process_offer);
 417         queue_work(newchannel->controlwq, &newchannel->work);
 418 }
 419
 420 /*
 421  * vmbus_onoffer_rescind - Rescind offer handler.
 422  *
 423  * We queue a work item to process this offer synchronously
 424  */
 425 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 426 {
 427         struct vmbus_channel_rescind_offer *rescind;
 428         struct vmbus_channel *channel;
 429
 430         rescind = (struct vmbus_channel_rescind_offer *)hdr;
 431         channel = relid2channel(rescind->child_relid);
 432
 433         if (channel == NULL)
 434                 /* Just return here, no channel found */
 435                 return;
 436
 437         /* work is initialized for vmbus_process_rescind_offer() from
 438          * vmbus_process_offer() where the channel got created */
 439         queue_work(channel->controlwq, &channel->work);
 440 }
 441
 442 /*
 443  * vmbus_onoffers_delivered -
 444  * This is invoked when all offers have been delivered.
 445  *
 446  * Nothing to do here.
 447  */
 448 static void vmbus_onoffers_delivered(
 449                         struct vmbus_channel_message_header *hdr)
 450 {
 451 }
 452
 453 /*
 454  * vmbus_onopen_result - Open result handler.
 455  *
 456  * This is invoked when we received a response to our channel open request.
 457  * Find the matching request, copy the response and signal the requesting
 458  * thread.
 459  */
 460 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
 461 {
 462         struct vmbus_channel_open_result *result;
 463         struct vmbus_channel_msginfo *msginfo;
 464         struct vmbus_channel_message_header *requestheader;
 465         struct vmbus_channel_open_channel *openmsg;
 466         unsigned long flags;
 467
 468         result = (struct vmbus_channel_open_result *)hdr;
 469
 470         /*
 471          * Find the open msg, copy the result and signal/unblock the wait event
 472          */
 473         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 474
 475         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 476                                 msglistentry) {
 477                 requestheader =
 478                         (struct vmbus_channel_message_header *)msginfo->msg;
 479
 480                 if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
 481                         openmsg =
 482                         (struct vmbus_channel_open_channel *)msginfo->msg;
 483                         if (openmsg->child_relid == result->child_relid &&
 484                             openmsg->openid == result->openid) {
 485                                 memcpy(&msginfo->response.open_result,
 486                                        result,
 487                                        sizeof(
 488                                         struct vmbus_channel_open_result));
 489                                 complete(&msginfo->waitevent);
 490                                 break;
 491                         }
 492                 }
 493         }
 494         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 495 }
 496
 497 /*
 498  * vmbus_ongpadl_created - GPADL created handler.
 499  *
 500  * This is invoked when we received a response to our gpadl create request.
 501  * Find the matching request, copy the response and signal the requesting
 502  * thread.
 503  */
 504 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
 505 {
 506         struct vmbus_channel_gpadl_created *gpadlcreated;
 507         struct vmbus_channel_msginfo *msginfo;
 508         struct vmbus_channel_message_header *requestheader;
 509         struct vmbus_channel_gpadl_header *gpadlheader;
 510         unsigned long flags;
 511
 512         gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
 513
 514         /*
 515          * Find the establish msg, copy the result and signal/unblock the wait
 516          * event
 517          */
 518         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 519
 520         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 521                                 msglistentry) {
 522                 requestheader =
 523                         (struct vmbus_channel_message_header *)msginfo->msg;
 524
 525                 if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
 526                         gpadlheader =
 527                         (struct vmbus_channel_gpadl_header *)requestheader;
 528
 529                         if ((gpadlcreated->child_relid ==
 530                              gpadlheader->child_relid) &&
 531                             (gpadlcreated->gpadl == gpadlheader->gpadl)) {
 532                                 memcpy(&msginfo->response.gpadl_created,
 533                                        gpadlcreated,
 534                                        sizeof(
 535                                         struct vmbus_channel_gpadl_created));
 536                                 complete(&msginfo->waitevent);
 537                                 break;
 538                         }
 539                 }
 540         }
 541         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 542 }
 543
 544 /*
 545  * vmbus_ongpadl_torndown - GPADL torndown handler.
 546  *
 547  * This is invoked when we received a response to our gpadl teardown request.
 548  * Find the matching request, copy the response and signal the requesting
 549  * thread.
 550  */
 551 static void vmbus_ongpadl_torndown(
 552                         struct vmbus_channel_message_header *hdr)
 553 {
 554         struct vmbus_channel_gpadl_torndown *gpadl_torndown;
 555         struct vmbus_channel_msginfo *msginfo;
 556         struct vmbus_channel_message_header *requestheader;
 557         struct vmbus_channel_gpadl_teardown *gpadl_teardown;
 558         unsigned long flags;
 559
 560         gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
 561
 562         /*
 563          * Find the open msg, copy the result and signal/unblock the wait event
 564          */
 565         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 566
 567         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 568                                 msglistentry) {
 569                 requestheader =
 570                         (struct vmbus_channel_message_header *)msginfo->msg;
 571
 572                 if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
 573                         gpadl_teardown =
 574                         (struct vmbus_channel_gpadl_teardown *)requestheader;
 575
 576                         if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
 577                                 memcpy(&msginfo->response.gpadl_torndown,
 578                                        gpadl_torndown,
 579                                        sizeof(
 580                                         struct vmbus_channel_gpadl_torndown));
 581                                 complete(&msginfo->waitevent);
 582                                 break;
 583                         }
 584                 }
 585         }
 586         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 587 }
 588
 589 /*
 590  * vmbus_onversion_response - Version response handler
 591  *
 592  * This is invoked when we received a response to our initiate contact request.
 593  * Find the matching request, copy the response and signal the requesting
 594  * thread.
 595  */
 596 static void vmbus_onversion_response(
 597                 struct vmbus_channel_message_header *hdr)
 598 {
 599         struct vmbus_channel_msginfo *msginfo;
 600         struct vmbus_channel_message_header *requestheader;
 601         struct vmbus_channel_version_response *version_response;
 602         unsigned long flags;
 603
 604         version_response = (struct vmbus_channel_version_response *)hdr;
 605         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 606
 607         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 608                                 msglistentry) {
 609                 requestheader =
 610                         (struct vmbus_channel_message_header *)msginfo->msg;
 611
 612                 if (requestheader->msgtype ==
 613                     CHANNELMSG_INITIATE_CONTACT) {
 614                         memcpy(&msginfo->response.version_response,
 615                               version_response,
 616                               sizeof(struct vmbus_channel_version_response));
 617                         complete(&msginfo->waitevent);
 618                 }
 619         }
 620         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 621 }
 622
 623 /* Channel message dispatch table */
 624 static struct vmbus_channel_message_table_entry
 625         channel_message_table[CHANNELMSG_COUNT] = {
 626         {CHANNELMSG_INVALID,                    NULL},
 627         {CHANNELMSG_OFFERCHANNEL,               vmbus_onoffer},
 628         {CHANNELMSG_RESCIND_CHANNELOFFER,       vmbus_onoffer_rescind},
 629         {CHANNELMSG_REQUESTOFFERS,              NULL},
 630         {CHANNELMSG_ALLOFFERS_DELIVERED,        vmbus_onoffers_delivered},
 631         {CHANNELMSG_OPENCHANNEL,                NULL},
 632         {CHANNELMSG_OPENCHANNEL_RESULT, vmbus_onopen_result},
 633         {CHANNELMSG_CLOSECHANNEL,               NULL},
 634         {CHANNELMSG_GPADL_HEADER,               NULL},
 635         {CHANNELMSG_GPADL_BODY,         NULL},
 636         {CHANNELMSG_GPADL_CREATED,              vmbus_ongpadl_created},
 637         {CHANNELMSG_GPADL_TEARDOWN,             NULL},
 638         {CHANNELMSG_GPADL_TORNDOWN,             vmbus_ongpadl_torndown},
 639         {CHANNELMSG_RELID_RELEASED,             NULL},
 640         {CHANNELMSG_INITIATE_CONTACT,           NULL},
 641         {CHANNELMSG_VERSION_RESPONSE,           vmbus_onversion_response},
 642         {CHANNELMSG_UNLOAD,                     NULL},
 643 };
 644
 645 /*
 646  * vmbus_onmessage - Handler for channel protocol messages.
 647  *
 648  * This is invoked in the vmbus worker thread context.
 649  */
 650 void vmbus_onmessage(void *context)
 651 {
 652         struct hv_message *msg = context;
 653         struct vmbus_channel_message_header *hdr;
 654         int size;
 655
 656         hdr = (struct vmbus_channel_message_header *)msg->u.payload;
 657         size = msg->header.payload_size;
 658
 659         if (hdr->msgtype >= CHANNELMSG_COUNT) {
 660                 pr_err("Received invalid channel message type %d size %d\n",
 661                            hdr->msgtype, size);
 662                 print_hex_dump_bytes("", DUMP_PREFIX_NONE,
 663                                      (unsigned char *)msg->u.payload, size);
 664                 return;
 665         }
 666
 667         if (channel_message_table[hdr->msgtype].message_handler)
 668                 channel_message_table[hdr->msgtype].message_handler(hdr);
 669         else
 670                 pr_err("Unhandled channel message type %d\n", hdr->msgtype);
 671 }
 672
 673 /*
 674  * vmbus_request_offers - Send a request to get all our pending offers.
 675  */
 676 int vmbus_request_offers(void)
 677 {
 678         struct vmbus_channel_message_header *msg;
 679         struct vmbus_channel_msginfo *msginfo;
 680         int ret, t;
 681
 682         msginfo = kmalloc(sizeof(*msginfo) +
 683                           sizeof(struct vmbus_channel_message_header),
 684                           GFP_KERNEL);
 685         if (!msginfo)
 686                 return -ENOMEM;
 687
 688         init_completion(&msginfo->waitevent);
 689
 690         msg = (struct vmbus_channel_message_header *)msginfo->msg;
 691
 692         msg->msgtype = CHANNELMSG_REQUESTOFFERS;
 693
 694
 695         ret = vmbus_post_msg(msg,
 696                                sizeof(struct vmbus_channel_message_header));
 697         if (ret != 0) {
 698                 pr_err("Unable to request offers - %d\n", ret);
 699
 700                 goto cleanup;
 701         }
 702
 703         t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
 704         if (t == 0) {
 705                 ret = -ETIMEDOUT;
 706                 goto cleanup;
 707         }
 708
 709
 710
 711 cleanup:
 712         kfree(msginfo);
 713
 714         return ret;
 715 }
 716
 717 /*
 718  * Retrieve the (sub) channel on which to send an outgoing request.
 719  * When a primary channel has multiple sub-channels, we choose a
 720  * channel whose VCPU binding is closest to the VCPU on which
 721  * this call is being made.
 722  */
 723 struct vmbus_channel *vmbus_get_outgoing_channel(struct vmbus_channel *primary)
 724 {
 725         struct list_head *cur, *tmp;
 726         int cur_cpu = hv_context.vp_index[smp_processor_id()];
 727         struct vmbus_channel *cur_channel;
 728         struct vmbus_channel *outgoing_channel = primary;
 729         int cpu_distance, new_cpu_distance;
 730
 731         if (list_empty(&primary->sc_list))
 732                 return outgoing_channel;
 733
 734         list_for_each_safe(cur, tmp, &primary->sc_list) {
 735                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 736                 if (cur_channel->state != CHANNEL_OPENED_STATE)
 737                         continue;
 738
 739                 if (cur_channel->target_vp == cur_cpu)
 740                         return cur_channel;
 741
 742                 cpu_distance = ((outgoing_channel->target_vp > cur_cpu) ?
 743                                 (outgoing_channel->target_vp - cur_cpu) :
 744                                 (cur_cpu - outgoing_channel->target_vp));
 745
 746                 new_cpu_distance = ((cur_channel->target_vp > cur_cpu) ?
 747                                 (cur_channel->target_vp - cur_cpu) :
 748                                 (cur_cpu - cur_channel->target_vp));
 749
 750                 if (cpu_distance < new_cpu_distance)
 751                         continue;
 752
 753                 outgoing_channel = cur_channel;
 754         }
 755
 756         return outgoing_channel;
 757 }
 758 EXPORT_SYMBOL_GPL(vmbus_get_outgoing_channel);
 759
 760 static void invoke_sc_cb(struct vmbus_channel *primary_channel)
 761 {
 762         struct list_head *cur, *tmp;
 763         struct vmbus_channel *cur_channel;
 764
 765         if (primary_channel->sc_creation_callback == NULL)
 766                 return;
 767
 768         list_for_each_safe(cur, tmp, &primary_channel->sc_list) {
 769                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 770
 771                 primary_channel->sc_creation_callback(cur_channel);
 772         }
 773 }
 774
 775 void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
 776                                 void (*sc_cr_cb)(struct vmbus_channel *new_sc))
 777 {
 778         primary_channel->sc_creation_callback = sc_cr_cb;
 779 }
 780 EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
 781
 782 bool vmbus_are_subchannels_present(struct vmbus_channel *primary)
 783 {
 784         bool ret;
 785
 786         ret = !list_empty(&primary->sc_list);
 787
 788         if (ret) {
 789                 /*
 790                  * Invoke the callback on sub-channel creation.
 791                  * This will present a uniform interface to the
 792                  * clients.
 793                  */
 794                 invoke_sc_cb(primary);
 795         }
 796
 797         return ret;
 798 }
 799 EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present);