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 fw_version specifies the  framework version that
  52  * we can support and srv_version specifies the service
  53  * version we can support.
  54  *
  55  * Mainly used by Hyper-V drivers.
  56  */
  57 bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
  58                                 struct icmsg_negotiate *negop, u8 *buf,
  59                                 int fw_version, int srv_version)
  60 {
  61         int icframe_major, icframe_minor;
  62         int icmsg_major, icmsg_minor;
  63         int fw_major, fw_minor;
  64         int srv_major, srv_minor;
  65         int i;
  66         bool found_match = false;
  67
  68         icmsghdrp->icmsgsize = 0x10;
  69         fw_major = (fw_version >> 16);
  70         fw_minor = (fw_version & 0xFFFF);
  71
  72         srv_major = (srv_version >> 16);
  73         srv_minor = (srv_version & 0xFFFF);
  74
  75         negop = (struct icmsg_negotiate *)&buf[
  76                 sizeof(struct vmbuspipe_hdr) +
  77                 sizeof(struct icmsg_hdr)];
  78
  79         icframe_major = negop->icframe_vercnt;
  80         icframe_minor = 0;
  81
  82         icmsg_major = negop->icmsg_vercnt;
  83         icmsg_minor = 0;
  84
  85         /*
  86          * Select the framework version number we will
  87          * support.
  88          */
  89
  90         for (i = 0; i < negop->icframe_vercnt; i++) {
  91                 if ((negop->icversion_data[i].major == fw_major) &&
  92                    (negop->icversion_data[i].minor == fw_minor)) {
  93                         icframe_major = negop->icversion_data[i].major;
  94                         icframe_minor = negop->icversion_data[i].minor;
  95                         found_match = true;
  96                 }
  97         }
  98
  99         if (!found_match)
 100                 goto fw_error;
 101
 102         found_match = false;
 103
 104         for (i = negop->icframe_vercnt;
 105                  (i < negop->icframe_vercnt + negop->icmsg_vercnt); i++) {
 106                 if ((negop->icversion_data[i].major == srv_major) &&
 107                    (negop->icversion_data[i].minor == srv_minor)) {
 108                         icmsg_major = negop->icversion_data[i].major;
 109                         icmsg_minor = negop->icversion_data[i].minor;
 110                         found_match = true;
 111                 }
 112         }
 113
 114         /*
 115          * Respond with the framework and service
 116          * version numbers we can support.
 117          */
 118
 119 fw_error:
 120         if (!found_match) {
 121                 negop->icframe_vercnt = 0;
 122                 negop->icmsg_vercnt = 0;
 123         } else {
 124                 negop->icframe_vercnt = 1;
 125                 negop->icmsg_vercnt = 1;
 126         }
 127
 128         negop->icversion_data[0].major = icframe_major;
 129         negop->icversion_data[0].minor = icframe_minor;
 130         negop->icversion_data[1].major = icmsg_major;
 131         negop->icversion_data[1].minor = icmsg_minor;
 132         return found_match;
 133 }
 134
 135 EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);
 136
 137 /*
 138  * alloc_channel - Allocate and initialize a vmbus channel object
 139  */
 140 static struct vmbus_channel *alloc_channel(void)
 141 {
 142         struct vmbus_channel *channel;
 143
 144         channel = kzalloc(sizeof(*channel), GFP_ATOMIC);
 145         if (!channel)
 146                 return NULL;
 147
 148         spin_lock_init(&channel->inbound_lock);
 149         spin_lock_init(&channel->sc_lock);
 150
 151         INIT_LIST_HEAD(&channel->sc_list);
 152
 153         channel->controlwq = create_workqueue("hv_vmbus_ctl");
 154         if (!channel->controlwq) {
 155                 kfree(channel);
 156                 return NULL;
 157         }
 158
 159         return channel;
 160 }
 161
 162 /*
 163  * release_hannel - Release the vmbus channel object itself
 164  */
 165 static void release_channel(struct work_struct *work)
 166 {
 167         struct vmbus_channel *channel = container_of(work,
 168                                                      struct vmbus_channel,
 169                                                      work);
 170
 171         destroy_workqueue(channel->controlwq);
 172
 173         kfree(channel);
 174 }
 175
 176 /*
 177  * free_channel - Release the resources used by the vmbus channel object
 178  */
 179 static void free_channel(struct vmbus_channel *channel)
 180 {
 181
 182         /*
 183          * We have to release the channel's workqueue/thread in the vmbus's
 184          * workqueue/thread context
 185          * ie we can't destroy ourselves.
 186          */
 187         INIT_WORK(&channel->work, release_channel);
 188         queue_work(vmbus_connection.work_queue, &channel->work);
 189 }
 190
 191
 192
 193 /*
 194  * vmbus_process_rescind_offer -
 195  * Rescind the offer by initiating a device removal
 196  */
 197 static void vmbus_process_rescind_offer(struct work_struct *work)
 198 {
 199         struct vmbus_channel *channel = container_of(work,
 200                                                      struct vmbus_channel,
 201                                                      work);
 202         unsigned long flags;
 203         struct vmbus_channel *primary_channel;
 204         struct vmbus_channel_relid_released msg;
 205
 206         vmbus_device_unregister(channel->device_obj);
 207         memset(&msg, 0, sizeof(struct vmbus_channel_relid_released));
 208         msg.child_relid = channel->offermsg.child_relid;
 209         msg.header.msgtype = CHANNELMSG_RELID_RELEASED;
 210         vmbus_post_msg(&msg, sizeof(struct vmbus_channel_relid_released));
 211
 212         if (channel->primary_channel == NULL) {
 213                 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 214                 list_del(&channel->listentry);
 215                 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 216         } else {
 217                 primary_channel = channel->primary_channel;
 218                 spin_lock_irqsave(&primary_channel->sc_lock, flags);
 219                 list_del(&channel->listentry);
 220                 spin_unlock_irqrestore(&primary_channel->sc_lock, flags);
 221         }
 222         free_channel(channel);
 223 }
 224
 225 void vmbus_free_channels(void)
 226 {
 227         struct vmbus_channel *channel;
 228
 229         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 230                 vmbus_device_unregister(channel->device_obj);
 231                 kfree(channel->device_obj);
 232                 free_channel(channel);
 233         }
 234 }
 235
 236 /*
 237  * vmbus_process_offer - Process the offer by creating a channel/device
 238  * associated with this offer
 239  */
 240 static void vmbus_process_offer(struct work_struct *work)
 241 {
 242         struct vmbus_channel *newchannel = container_of(work,
 243                                                         struct vmbus_channel,
 244                                                         work);
 245         struct vmbus_channel *channel;
 246         bool fnew = true;
 247         int ret;
 248         unsigned long flags;
 249
 250         /* The next possible work is rescind handling */
 251         INIT_WORK(&newchannel->work, vmbus_process_rescind_offer);
 252
 253         /* Make sure this is a new offer */
 254         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 255
 256         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 257                 if (!uuid_le_cmp(channel->offermsg.offer.if_type,
 258                         newchannel->offermsg.offer.if_type) &&
 259                         !uuid_le_cmp(channel->offermsg.offer.if_instance,
 260                                 newchannel->offermsg.offer.if_instance)) {
 261                         fnew = false;
 262                         break;
 263                 }
 264         }
 265
 266         if (fnew)
 267                 list_add_tail(&newchannel->listentry,
 268                               &vmbus_connection.chn_list);
 269
 270         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 271
 272         if (!fnew) {
 273                 /*
 274                  * Check to see if this is a sub-channel.
 275                  */
 276                 if (newchannel->offermsg.offer.sub_channel_index != 0) {
 277                         /*
 278                          * Process the sub-channel.
 279                          */
 280                         newchannel->primary_channel = channel;
 281                         spin_lock_irqsave(&channel->sc_lock, flags);
 282                         list_add_tail(&newchannel->sc_list, &channel->sc_list);
 283                         spin_unlock_irqrestore(&channel->sc_lock, flags);
 284                         newchannel->state = CHANNEL_OPEN_STATE;
 285                         if (channel->sc_creation_callback != NULL)
 286                                 channel->sc_creation_callback(newchannel);
 287
 288                         return;
 289                 }
 290
 291                 free_channel(newchannel);
 292                 return;
 293         }
 294
 295         /*
 296          * This state is used to indicate a successful open
 297          * so that when we do close the channel normally, we
 298          * can cleanup properly
 299          */
 300         newchannel->state = CHANNEL_OPEN_STATE;
 301
 302         /*
 303          * Start the process of binding this offer to the driver
 304          * We need to set the DeviceObject field before calling
 305          * vmbus_child_dev_add()
 306          */
 307         newchannel->device_obj = vmbus_device_create(
 308                 &newchannel->offermsg.offer.if_type,
 309                 &newchannel->offermsg.offer.if_instance,
 310                 newchannel);
 311
 312         /*
 313          * Add the new device to the bus. This will kick off device-driver
 314          * binding which eventually invokes the device driver's AddDevice()
 315          * method.
 316          */
 317         ret = vmbus_device_register(newchannel->device_obj);
 318         if (ret != 0) {
 319                 pr_err("unable to add child device object (relid %d)\n",
 320                            newchannel->offermsg.child_relid);
 321
 322                 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 323                 list_del(&newchannel->listentry);
 324                 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 325                 kfree(newchannel->device_obj);
 326
 327                 free_channel(newchannel);
 328         }
 329 }
 330
 331 enum {
 332         IDE = 0,
 333         SCSI,
 334         NIC,
 335         MAX_PERF_CHN,
 336 };
 337
 338 /*
 339  * This is an array of device_ids (device types) that are performance critical.
 340  * We attempt to distribute the interrupt load for these devices across
 341  * all available CPUs.
 342  */
 343 static const struct hv_vmbus_device_id hp_devs[] = {
 344         /* IDE */
 345         { HV_IDE_GUID, },
 346         /* Storage - SCSI */
 347         { HV_SCSI_GUID, },
 348         /* Network */
 349         { HV_NIC_GUID, },
 350 };
 351
 352
 353 /*
 354  * We use this state to statically distribute the channel interrupt load.
 355  */
 356 static u32  next_vp;
 357
 358 /*
 359  * Starting with Win8, we can statically distribute the incoming
 360  * channel interrupt load by binding a channel to VCPU. We
 361  * implement here a simple round robin scheme for distributing
 362  * the interrupt load.
 363  * We will bind channels that are not performance critical to cpu 0 and
 364  * performance critical channels (IDE, SCSI and Network) will be uniformly
 365  * distributed across all available CPUs.
 366  */
 367 static u32 get_vp_index(uuid_le *type_guid)
 368 {
 369         u32 cur_cpu;
 370         int i;
 371         bool perf_chn = false;
 372         u32 max_cpus = num_online_cpus();
 373
 374         for (i = IDE; i < MAX_PERF_CHN; i++) {
 375                 if (!memcmp(type_guid->b, hp_devs[i].guid,
 376                                  sizeof(uuid_le))) {
 377                         perf_chn = true;
 378                         break;
 379                 }
 380         }
 381         if ((vmbus_proto_version == VERSION_WS2008) ||
 382             (vmbus_proto_version == VERSION_WIN7) || (!perf_chn)) {
 383                 /*
 384                  * Prior to win8, all channel interrupts are
 385                  * delivered on cpu 0.
 386                  * Also if the channel is not a performance critical
 387                  * channel, bind it to cpu 0.
 388                  */
 389                 return 0;
 390         }
 391         cur_cpu = (++next_vp % max_cpus);
 392         return hv_context.vp_index[cur_cpu];
 393 }
 394
 395 /*
 396  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 397  *
 398  */
 399 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 400 {
 401         struct vmbus_channel_offer_channel *offer;
 402         struct vmbus_channel *newchannel;
 403
 404         offer = (struct vmbus_channel_offer_channel *)hdr;
 405
 406         /* Allocate the channel object and save this offer. */
 407         newchannel = alloc_channel();
 408         if (!newchannel) {
 409                 pr_err("Unable to allocate channel object\n");
 410                 return;
 411         }
 412
 413         /*
 414          * By default we setup state to enable batched
 415          * reading. A specific service can choose to
 416          * disable this prior to opening the channel.
 417          */
 418         newchannel->batched_reading = true;
 419
 420         /*
 421          * Setup state for signalling the host.
 422          */
 423         newchannel->sig_event = (struct hv_input_signal_event *)
 424                                 (ALIGN((unsigned long)
 425                                 &newchannel->sig_buf,
 426                                 HV_HYPERCALL_PARAM_ALIGN));
 427
 428         newchannel->sig_event->connectionid.asu32 = 0;
 429         newchannel->sig_event->connectionid.u.id = VMBUS_EVENT_CONNECTION_ID;
 430         newchannel->sig_event->flag_number = 0;
 431         newchannel->sig_event->rsvdz = 0;
 432
 433         if (vmbus_proto_version != VERSION_WS2008) {
 434                 newchannel->is_dedicated_interrupt =
 435                                 (offer->is_dedicated_interrupt != 0);
 436                 newchannel->sig_event->connectionid.u.id =
 437                                 offer->connection_id;
 438         }
 439
 440         newchannel->target_vp = get_vp_index(&offer->offer.if_type);
 441
 442         memcpy(&newchannel->offermsg, offer,
 443                sizeof(struct vmbus_channel_offer_channel));
 444         newchannel->monitor_grp = (u8)offer->monitorid / 32;
 445         newchannel->monitor_bit = (u8)offer->monitorid % 32;
 446
 447         INIT_WORK(&newchannel->work, vmbus_process_offer);
 448         queue_work(newchannel->controlwq, &newchannel->work);
 449 }
 450
 451 /*
 452  * vmbus_onoffer_rescind - Rescind offer handler.
 453  *
 454  * We queue a work item to process this offer synchronously
 455  */
 456 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 457 {
 458         struct vmbus_channel_rescind_offer *rescind;
 459         struct vmbus_channel *channel;
 460
 461         rescind = (struct vmbus_channel_rescind_offer *)hdr;
 462         channel = relid2channel(rescind->child_relid);
 463
 464         if (channel == NULL)
 465                 /* Just return here, no channel found */
 466                 return;
 467
 468         /* work is initialized for vmbus_process_rescind_offer() from
 469          * vmbus_process_offer() where the channel got created */
 470         queue_work(channel->controlwq, &channel->work);
 471 }
 472
 473 /*
 474  * vmbus_onoffers_delivered -
 475  * This is invoked when all offers have been delivered.
 476  *
 477  * Nothing to do here.
 478  */
 479 static void vmbus_onoffers_delivered(
 480                         struct vmbus_channel_message_header *hdr)
 481 {
 482 }
 483
 484 /*
 485  * vmbus_onopen_result - Open result handler.
 486  *
 487  * This is invoked when we received a response to our channel open request.
 488  * Find the matching request, copy the response and signal the requesting
 489  * thread.
 490  */
 491 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
 492 {
 493         struct vmbus_channel_open_result *result;
 494         struct vmbus_channel_msginfo *msginfo;
 495         struct vmbus_channel_message_header *requestheader;
 496         struct vmbus_channel_open_channel *openmsg;
 497         unsigned long flags;
 498
 499         result = (struct vmbus_channel_open_result *)hdr;
 500
 501         /*
 502          * Find the open msg, copy the result and signal/unblock the wait event
 503          */
 504         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 505
 506         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 507                                 msglistentry) {
 508                 requestheader =
 509                         (struct vmbus_channel_message_header *)msginfo->msg;
 510
 511                 if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
 512                         openmsg =
 513                         (struct vmbus_channel_open_channel *)msginfo->msg;
 514                         if (openmsg->child_relid == result->child_relid &&
 515                             openmsg->openid == result->openid) {
 516                                 memcpy(&msginfo->response.open_result,
 517                                        result,
 518                                        sizeof(
 519                                         struct vmbus_channel_open_result));
 520                                 complete(&msginfo->waitevent);
 521                                 break;
 522                         }
 523                 }
 524         }
 525         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 526 }
 527
 528 /*
 529  * vmbus_ongpadl_created - GPADL created handler.
 530  *
 531  * This is invoked when we received a response to our gpadl create request.
 532  * Find the matching request, copy the response and signal the requesting
 533  * thread.
 534  */
 535 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
 536 {
 537         struct vmbus_channel_gpadl_created *gpadlcreated;
 538         struct vmbus_channel_msginfo *msginfo;
 539         struct vmbus_channel_message_header *requestheader;
 540         struct vmbus_channel_gpadl_header *gpadlheader;
 541         unsigned long flags;
 542
 543         gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
 544
 545         /*
 546          * Find the establish msg, copy the result and signal/unblock the wait
 547          * event
 548          */
 549         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 550
 551         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 552                                 msglistentry) {
 553                 requestheader =
 554                         (struct vmbus_channel_message_header *)msginfo->msg;
 555
 556                 if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
 557                         gpadlheader =
 558                         (struct vmbus_channel_gpadl_header *)requestheader;
 559
 560                         if ((gpadlcreated->child_relid ==
 561                              gpadlheader->child_relid) &&
 562                             (gpadlcreated->gpadl == gpadlheader->gpadl)) {
 563                                 memcpy(&msginfo->response.gpadl_created,
 564                                        gpadlcreated,
 565                                        sizeof(
 566                                         struct vmbus_channel_gpadl_created));
 567                                 complete(&msginfo->waitevent);
 568                                 break;
 569                         }
 570                 }
 571         }
 572         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 573 }
 574
 575 /*
 576  * vmbus_ongpadl_torndown - GPADL torndown handler.
 577  *
 578  * This is invoked when we received a response to our gpadl teardown request.
 579  * Find the matching request, copy the response and signal the requesting
 580  * thread.
 581  */
 582 static void vmbus_ongpadl_torndown(
 583                         struct vmbus_channel_message_header *hdr)
 584 {
 585         struct vmbus_channel_gpadl_torndown *gpadl_torndown;
 586         struct vmbus_channel_msginfo *msginfo;
 587         struct vmbus_channel_message_header *requestheader;
 588         struct vmbus_channel_gpadl_teardown *gpadl_teardown;
 589         unsigned long flags;
 590
 591         gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
 592
 593         /*
 594          * Find the open msg, copy the result and signal/unblock the wait event
 595          */
 596         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 597
 598         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 599                                 msglistentry) {
 600                 requestheader =
 601                         (struct vmbus_channel_message_header *)msginfo->msg;
 602
 603                 if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
 604                         gpadl_teardown =
 605                         (struct vmbus_channel_gpadl_teardown *)requestheader;
 606
 607                         if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
 608                                 memcpy(&msginfo->response.gpadl_torndown,
 609                                        gpadl_torndown,
 610                                        sizeof(
 611                                         struct vmbus_channel_gpadl_torndown));
 612                                 complete(&msginfo->waitevent);
 613                                 break;
 614                         }
 615                 }
 616         }
 617         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 618 }
 619
 620 /*
 621  * vmbus_onversion_response - Version response handler
 622  *
 623  * This is invoked when we received a response to our initiate contact request.
 624  * Find the matching request, copy the response and signal the requesting
 625  * thread.
 626  */
 627 static void vmbus_onversion_response(
 628                 struct vmbus_channel_message_header *hdr)
 629 {
 630         struct vmbus_channel_msginfo *msginfo;
 631         struct vmbus_channel_message_header *requestheader;
 632         struct vmbus_channel_version_response *version_response;
 633         unsigned long flags;
 634
 635         version_response = (struct vmbus_channel_version_response *)hdr;
 636         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 637
 638         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 639                                 msglistentry) {
 640                 requestheader =
 641                         (struct vmbus_channel_message_header *)msginfo->msg;
 642
 643                 if (requestheader->msgtype ==
 644                     CHANNELMSG_INITIATE_CONTACT) {
 645                         memcpy(&msginfo->response.version_response,
 646                               version_response,
 647                               sizeof(struct vmbus_channel_version_response));
 648                         complete(&msginfo->waitevent);
 649                 }
 650         }
 651         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 652 }
 653
 654 /* Channel message dispatch table */
 655 static struct vmbus_channel_message_table_entry
 656         channel_message_table[CHANNELMSG_COUNT] = {
 657         {CHANNELMSG_INVALID,                    NULL},
 658         {CHANNELMSG_OFFERCHANNEL,               vmbus_onoffer},
 659         {CHANNELMSG_RESCIND_CHANNELOFFER,       vmbus_onoffer_rescind},
 660         {CHANNELMSG_REQUESTOFFERS,              NULL},
 661         {CHANNELMSG_ALLOFFERS_DELIVERED,        vmbus_onoffers_delivered},
 662         {CHANNELMSG_OPENCHANNEL,                NULL},
 663         {CHANNELMSG_OPENCHANNEL_RESULT, vmbus_onopen_result},
 664         {CHANNELMSG_CLOSECHANNEL,               NULL},
 665         {CHANNELMSG_GPADL_HEADER,               NULL},
 666         {CHANNELMSG_GPADL_BODY,         NULL},
 667         {CHANNELMSG_GPADL_CREATED,              vmbus_ongpadl_created},
 668         {CHANNELMSG_GPADL_TEARDOWN,             NULL},
 669         {CHANNELMSG_GPADL_TORNDOWN,             vmbus_ongpadl_torndown},
 670         {CHANNELMSG_RELID_RELEASED,             NULL},
 671         {CHANNELMSG_INITIATE_CONTACT,           NULL},
 672         {CHANNELMSG_VERSION_RESPONSE,           vmbus_onversion_response},
 673         {CHANNELMSG_UNLOAD,                     NULL},
 674 };
 675
 676 /*
 677  * vmbus_onmessage - Handler for channel protocol messages.
 678  *
 679  * This is invoked in the vmbus worker thread context.
 680  */
 681 void vmbus_onmessage(void *context)
 682 {
 683         struct hv_message *msg = context;
 684         struct vmbus_channel_message_header *hdr;
 685         int size;
 686
 687         hdr = (struct vmbus_channel_message_header *)msg->u.payload;
 688         size = msg->header.payload_size;
 689
 690         if (hdr->msgtype >= CHANNELMSG_COUNT) {
 691                 pr_err("Received invalid channel message type %d size %d\n",
 692                            hdr->msgtype, size);
 693                 print_hex_dump_bytes("", DUMP_PREFIX_NONE,
 694                                      (unsigned char *)msg->u.payload, size);
 695                 return;
 696         }
 697
 698         if (channel_message_table[hdr->msgtype].message_handler)
 699                 channel_message_table[hdr->msgtype].message_handler(hdr);
 700         else
 701                 pr_err("Unhandled channel message type %d\n", hdr->msgtype);
 702 }
 703
 704 /*
 705  * vmbus_request_offers - Send a request to get all our pending offers.
 706  */
 707 int vmbus_request_offers(void)
 708 {
 709         struct vmbus_channel_message_header *msg;
 710         struct vmbus_channel_msginfo *msginfo;
 711         int ret, t;
 712
 713         msginfo = kmalloc(sizeof(*msginfo) +
 714                           sizeof(struct vmbus_channel_message_header),
 715                           GFP_KERNEL);
 716         if (!msginfo)
 717                 return -ENOMEM;
 718
 719         init_completion(&msginfo->waitevent);
 720
 721         msg = (struct vmbus_channel_message_header *)msginfo->msg;
 722
 723         msg->msgtype = CHANNELMSG_REQUESTOFFERS;
 724
 725
 726         ret = vmbus_post_msg(msg,
 727                                sizeof(struct vmbus_channel_message_header));
 728         if (ret != 0) {
 729                 pr_err("Unable to request offers - %d\n", ret);
 730
 731                 goto cleanup;
 732         }
 733
 734         t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
 735         if (t == 0) {
 736                 ret = -ETIMEDOUT;
 737                 goto cleanup;
 738         }
 739
 740
 741
 742 cleanup:
 743         kfree(msginfo);
 744
 745         return ret;
 746 }
 747
 748 /*
 749  * Retrieve the (sub) channel on which to send an outgoing request.
 750  * When a primary channel has multiple sub-channels, we choose a
 751  * channel whose VCPU binding is closest to the VCPU on which
 752  * this call is being made.
 753  */
 754 struct vmbus_channel *vmbus_get_outgoing_channel(struct vmbus_channel *primary)
 755 {
 756         struct list_head *cur, *tmp;
 757         int cur_cpu = hv_context.vp_index[smp_processor_id()];
 758         struct vmbus_channel *cur_channel;
 759         struct vmbus_channel *outgoing_channel = primary;
 760         int cpu_distance, new_cpu_distance;
 761
 762         if (list_empty(&primary->sc_list))
 763                 return outgoing_channel;
 764
 765         list_for_each_safe(cur, tmp, &primary->sc_list) {
 766                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 767                 if (cur_channel->state != CHANNEL_OPENED_STATE)
 768                         continue;
 769
 770                 if (cur_channel->target_vp == cur_cpu)
 771                         return cur_channel;
 772
 773                 cpu_distance = ((outgoing_channel->target_vp > cur_cpu) ?
 774                                 (outgoing_channel->target_vp - cur_cpu) :
 775                                 (cur_cpu - outgoing_channel->target_vp));
 776
 777                 new_cpu_distance = ((cur_channel->target_vp > cur_cpu) ?
 778                                 (cur_channel->target_vp - cur_cpu) :
 779                                 (cur_cpu - cur_channel->target_vp));
 780
 781                 if (cpu_distance < new_cpu_distance)
 782                         continue;
 783
 784                 outgoing_channel = cur_channel;
 785         }
 786
 787         return outgoing_channel;
 788 }
 789 EXPORT_SYMBOL_GPL(vmbus_get_outgoing_channel);
 790
 791 static void invoke_sc_cb(struct vmbus_channel *primary_channel)
 792 {
 793         struct list_head *cur, *tmp;
 794         struct vmbus_channel *cur_channel;
 795
 796         if (primary_channel->sc_creation_callback == NULL)
 797                 return;
 798
 799         list_for_each_safe(cur, tmp, &primary_channel->sc_list) {
 800                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 801
 802                 primary_channel->sc_creation_callback(cur_channel);
 803         }
 804 }
 805
 806 void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
 807                                 void (*sc_cr_cb)(struct vmbus_channel *new_sc))
 808 {
 809         primary_channel->sc_creation_callback = sc_cr_cb;
 810 }
 811 EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
 812
 813 bool vmbus_are_subchannels_present(struct vmbus_channel *primary)
 814 {
 815         bool ret;
 816
 817         ret = !list_empty(&primary->sc_list);
 818
 819         if (ret) {
 820                 /*
 821                  * Invoke the callback on sub-channel creation.
 822                  * This will present a uniform interface to the
 823                  * clients.
 824                  */
 825                 invoke_sc_cb(primary);
 826         }
 827
 828         return ret;
 829 }
 830 EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present);