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         INIT_LIST_HEAD(&channel->percpu_list);
 153
 154         channel->controlwq = create_workqueue("hv_vmbus_ctl");
 155         if (!channel->controlwq) {
 156                 kfree(channel);
 157                 return NULL;
 158         }
 159
 160         return channel;
 161 }
 162
 163 /*
 164  * release_hannel - Release the vmbus channel object itself
 165  */
 166 static void release_channel(struct work_struct *work)
 167 {
 168         struct vmbus_channel *channel = container_of(work,
 169                                                      struct vmbus_channel,
 170                                                      work);
 171
 172         destroy_workqueue(channel->controlwq);
 173
 174         kfree(channel);
 175 }
 176
 177 /*
 178  * free_channel - Release the resources used by the vmbus channel object
 179  */
 180 static void free_channel(struct vmbus_channel *channel)
 181 {
 182
 183         /*
 184          * We have to release the channel's workqueue/thread in the vmbus's
 185          * workqueue/thread context
 186          * ie we can't destroy ourselves.
 187          */
 188         INIT_WORK(&channel->work, release_channel);
 189         queue_work(vmbus_connection.work_queue, &channel->work);
 190 }
 191
 192 static void percpu_channel_enq(void *arg)
 193 {
 194         struct vmbus_channel *channel = arg;
 195         int cpu = smp_processor_id();
 196
 197         list_add_tail(&channel->percpu_list, &hv_context.percpu_list[cpu]);
 198 }
 199
 200 static void percpu_channel_deq(void *arg)
 201 {
 202         struct vmbus_channel *channel = arg;
 203
 204         list_del(&channel->percpu_list);
 205 }
 206
 207 /*
 208  * vmbus_process_rescind_offer -
 209  * Rescind the offer by initiating a device removal
 210  */
 211 static void vmbus_process_rescind_offer(struct work_struct *work)
 212 {
 213         struct vmbus_channel *channel = container_of(work,
 214                                                      struct vmbus_channel,
 215                                                      work);
 216         unsigned long flags;
 217         struct vmbus_channel *primary_channel;
 218         struct vmbus_channel_relid_released msg;
 219
 220         if (channel->device_obj)
 221                 vmbus_device_unregister(channel->device_obj);
 222         memset(&msg, 0, sizeof(struct vmbus_channel_relid_released));
 223         msg.child_relid = channel->offermsg.child_relid;
 224         msg.header.msgtype = CHANNELMSG_RELID_RELEASED;
 225         vmbus_post_msg(&msg, sizeof(struct vmbus_channel_relid_released));
 226
 227         if (channel->target_cpu != get_cpu()) {
 228                 put_cpu();
 229                 smp_call_function_single(channel->target_cpu,
 230                                          percpu_channel_deq, channel, true);
 231         } else {
 232                 percpu_channel_deq(channel);
 233                 put_cpu();
 234         }
 235
 236         if (channel->primary_channel == NULL) {
 237                 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 238                 list_del(&channel->listentry);
 239                 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 240         } else {
 241                 primary_channel = channel->primary_channel;
 242                 spin_lock_irqsave(&primary_channel->sc_lock, flags);
 243                 list_del(&channel->sc_list);
 244                 spin_unlock_irqrestore(&primary_channel->sc_lock, flags);
 245         }
 246         free_channel(channel);
 247 }
 248
 249 void vmbus_free_channels(void)
 250 {
 251         struct vmbus_channel *channel;
 252
 253         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 254                 vmbus_device_unregister(channel->device_obj);
 255                 kfree(channel->device_obj);
 256                 free_channel(channel);
 257         }
 258 }
 259
 260 /*
 261  * vmbus_process_offer - Process the offer by creating a channel/device
 262  * associated with this offer
 263  */
 264 static void vmbus_process_offer(struct work_struct *work)
 265 {
 266         struct vmbus_channel *newchannel = container_of(work,
 267                                                         struct vmbus_channel,
 268                                                         work);
 269         struct vmbus_channel *channel;
 270         bool fnew = true;
 271         bool enq = false;
 272         int ret;
 273         unsigned long flags;
 274
 275         /* The next possible work is rescind handling */
 276         INIT_WORK(&newchannel->work, vmbus_process_rescind_offer);
 277
 278         /* Make sure this is a new offer */
 279         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 280
 281         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 282                 if (!uuid_le_cmp(channel->offermsg.offer.if_type,
 283                         newchannel->offermsg.offer.if_type) &&
 284                         !uuid_le_cmp(channel->offermsg.offer.if_instance,
 285                                 newchannel->offermsg.offer.if_instance)) {
 286                         fnew = false;
 287                         break;
 288                 }
 289         }
 290
 291         if (fnew) {
 292                 list_add_tail(&newchannel->listentry,
 293                               &vmbus_connection.chn_list);
 294                 enq = true;
 295         }
 296
 297         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 298
 299         if (enq) {
 300                 if (newchannel->target_cpu != get_cpu()) {
 301                         put_cpu();
 302                         smp_call_function_single(newchannel->target_cpu,
 303                                                  percpu_channel_enq,
 304                                                  newchannel, true);
 305                 } else {
 306                         percpu_channel_enq(newchannel);
 307                         put_cpu();
 308                 }
 309         }
 310         if (!fnew) {
 311                 /*
 312                  * Check to see if this is a sub-channel.
 313                  */
 314                 if (newchannel->offermsg.offer.sub_channel_index != 0) {
 315                         /*
 316                          * Process the sub-channel.
 317                          */
 318                         newchannel->primary_channel = channel;
 319                         spin_lock_irqsave(&channel->sc_lock, flags);
 320                         list_add_tail(&newchannel->sc_list, &channel->sc_list);
 321                         spin_unlock_irqrestore(&channel->sc_lock, flags);
 322
 323                         if (newchannel->target_cpu != get_cpu()) {
 324                                 put_cpu();
 325                                 smp_call_function_single(newchannel->target_cpu,
 326                                                          percpu_channel_enq,
 327                                                          newchannel, true);
 328                         } else {
 329                                 percpu_channel_enq(newchannel);
 330                                 put_cpu();
 331                         }
 332
 333                         newchannel->state = CHANNEL_OPEN_STATE;
 334                         if (channel->sc_creation_callback != NULL)
 335                                 channel->sc_creation_callback(newchannel);
 336
 337                         return;
 338                 }
 339
 340                 free_channel(newchannel);
 341                 return;
 342         }
 343
 344         /*
 345          * This state is used to indicate a successful open
 346          * so that when we do close the channel normally, we
 347          * can cleanup properly
 348          */
 349         newchannel->state = CHANNEL_OPEN_STATE;
 350
 351         /*
 352          * Start the process of binding this offer to the driver
 353          * We need to set the DeviceObject field before calling
 354          * vmbus_child_dev_add()
 355          */
 356         newchannel->device_obj = vmbus_device_create(
 357                 &newchannel->offermsg.offer.if_type,
 358                 &newchannel->offermsg.offer.if_instance,
 359                 newchannel);
 360
 361         /*
 362          * Add the new device to the bus. This will kick off device-driver
 363          * binding which eventually invokes the device driver's AddDevice()
 364          * method.
 365          */
 366         ret = vmbus_device_register(newchannel->device_obj);
 367         if (ret != 0) {
 368                 pr_err("unable to add child device object (relid %d)\n",
 369                            newchannel->offermsg.child_relid);
 370
 371                 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 372                 list_del(&newchannel->listentry);
 373                 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 374                 kfree(newchannel->device_obj);
 375
 376                 free_channel(newchannel);
 377         }
 378 }
 379
 380 enum {
 381         IDE = 0,
 382         SCSI,
 383         NIC,
 384         MAX_PERF_CHN,
 385 };
 386
 387 /*
 388  * This is an array of device_ids (device types) that are performance critical.
 389  * We attempt to distribute the interrupt load for these devices across
 390  * all available CPUs.
 391  */
 392 static const struct hv_vmbus_device_id hp_devs[] = {
 393         /* IDE */
 394         { HV_IDE_GUID, },
 395         /* Storage - SCSI */
 396         { HV_SCSI_GUID, },
 397         /* Network */
 398         { HV_NIC_GUID, },
 399 };
 400
 401
 402 /*
 403  * We use this state to statically distribute the channel interrupt load.
 404  */
 405 static u32  next_vp;
 406
 407 /*
 408  * Starting with Win8, we can statically distribute the incoming
 409  * channel interrupt load by binding a channel to VCPU. We
 410  * implement here a simple round robin scheme for distributing
 411  * the interrupt load.
 412  * We will bind channels that are not performance critical to cpu 0 and
 413  * performance critical channels (IDE, SCSI and Network) will be uniformly
 414  * distributed across all available CPUs.
 415  */
 416 static void init_vp_index(struct vmbus_channel *channel, const uuid_le *type_guid)
 417 {
 418         u32 cur_cpu;
 419         int i;
 420         bool perf_chn = false;
 421         u32 max_cpus = num_online_cpus();
 422
 423         for (i = IDE; i < MAX_PERF_CHN; i++) {
 424                 if (!memcmp(type_guid->b, hp_devs[i].guid,
 425                                  sizeof(uuid_le))) {
 426                         perf_chn = true;
 427                         break;
 428                 }
 429         }
 430         if ((vmbus_proto_version == VERSION_WS2008) ||
 431             (vmbus_proto_version == VERSION_WIN7) || (!perf_chn)) {
 432                 /*
 433                  * Prior to win8, all channel interrupts are
 434                  * delivered on cpu 0.
 435                  * Also if the channel is not a performance critical
 436                  * channel, bind it to cpu 0.
 437                  */
 438                 channel->target_cpu = 0;
 439                 channel->target_vp = 0;
 440                 return;
 441         }
 442         cur_cpu = (++next_vp % max_cpus);
 443         channel->target_cpu = cur_cpu;
 444         channel->target_vp = hv_context.vp_index[cur_cpu];
 445 }
 446
 447 /*
 448  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 449  *
 450  */
 451 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 452 {
 453         struct vmbus_channel_offer_channel *offer;
 454         struct vmbus_channel *newchannel;
 455
 456         offer = (struct vmbus_channel_offer_channel *)hdr;
 457
 458         /* Allocate the channel object and save this offer. */
 459         newchannel = alloc_channel();
 460         if (!newchannel) {
 461                 pr_err("Unable to allocate channel object\n");
 462                 return;
 463         }
 464
 465         /*
 466          * By default we setup state to enable batched
 467          * reading. A specific service can choose to
 468          * disable this prior to opening the channel.
 469          */
 470         newchannel->batched_reading = true;
 471
 472         /*
 473          * Setup state for signalling the host.
 474          */
 475         newchannel->sig_event = (struct hv_input_signal_event *)
 476                                 (ALIGN((unsigned long)
 477                                 &newchannel->sig_buf,
 478                                 HV_HYPERCALL_PARAM_ALIGN));
 479
 480         newchannel->sig_event->connectionid.asu32 = 0;
 481         newchannel->sig_event->connectionid.u.id = VMBUS_EVENT_CONNECTION_ID;
 482         newchannel->sig_event->flag_number = 0;
 483         newchannel->sig_event->rsvdz = 0;
 484
 485         if (vmbus_proto_version != VERSION_WS2008) {
 486                 newchannel->is_dedicated_interrupt =
 487                                 (offer->is_dedicated_interrupt != 0);
 488                 newchannel->sig_event->connectionid.u.id =
 489                                 offer->connection_id;
 490         }
 491
 492         init_vp_index(newchannel, &offer->offer.if_type);
 493
 494         memcpy(&newchannel->offermsg, offer,
 495                sizeof(struct vmbus_channel_offer_channel));
 496         newchannel->monitor_grp = (u8)offer->monitorid / 32;
 497         newchannel->monitor_bit = (u8)offer->monitorid % 32;
 498
 499         INIT_WORK(&newchannel->work, vmbus_process_offer);
 500         queue_work(newchannel->controlwq, &newchannel->work);
 501 }
 502
 503 /*
 504  * vmbus_onoffer_rescind - Rescind offer handler.
 505  *
 506  * We queue a work item to process this offer synchronously
 507  */
 508 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 509 {
 510         struct vmbus_channel_rescind_offer *rescind;
 511         struct vmbus_channel *channel;
 512
 513         rescind = (struct vmbus_channel_rescind_offer *)hdr;
 514         channel = relid2channel(rescind->child_relid);
 515
 516         if (channel == NULL)
 517                 /* Just return here, no channel found */
 518                 return;
 519
 520         /* work is initialized for vmbus_process_rescind_offer() from
 521          * vmbus_process_offer() where the channel got created */
 522         queue_work(channel->controlwq, &channel->work);
 523 }
 524
 525 /*
 526  * vmbus_onoffers_delivered -
 527  * This is invoked when all offers have been delivered.
 528  *
 529  * Nothing to do here.
 530  */
 531 static void vmbus_onoffers_delivered(
 532                         struct vmbus_channel_message_header *hdr)
 533 {
 534 }
 535
 536 /*
 537  * vmbus_onopen_result - Open result handler.
 538  *
 539  * This is invoked when we received a response to our channel open request.
 540  * Find the matching request, copy the response and signal the requesting
 541  * thread.
 542  */
 543 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
 544 {
 545         struct vmbus_channel_open_result *result;
 546         struct vmbus_channel_msginfo *msginfo;
 547         struct vmbus_channel_message_header *requestheader;
 548         struct vmbus_channel_open_channel *openmsg;
 549         unsigned long flags;
 550
 551         result = (struct vmbus_channel_open_result *)hdr;
 552
 553         /*
 554          * Find the open msg, copy the result and signal/unblock the wait event
 555          */
 556         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 557
 558         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 559                                 msglistentry) {
 560                 requestheader =
 561                         (struct vmbus_channel_message_header *)msginfo->msg;
 562
 563                 if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
 564                         openmsg =
 565                         (struct vmbus_channel_open_channel *)msginfo->msg;
 566                         if (openmsg->child_relid == result->child_relid &&
 567                             openmsg->openid == result->openid) {
 568                                 memcpy(&msginfo->response.open_result,
 569                                        result,
 570                                        sizeof(
 571                                         struct vmbus_channel_open_result));
 572                                 complete(&msginfo->waitevent);
 573                                 break;
 574                         }
 575                 }
 576         }
 577         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 578 }
 579
 580 /*
 581  * vmbus_ongpadl_created - GPADL created handler.
 582  *
 583  * This is invoked when we received a response to our gpadl create request.
 584  * Find the matching request, copy the response and signal the requesting
 585  * thread.
 586  */
 587 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
 588 {
 589         struct vmbus_channel_gpadl_created *gpadlcreated;
 590         struct vmbus_channel_msginfo *msginfo;
 591         struct vmbus_channel_message_header *requestheader;
 592         struct vmbus_channel_gpadl_header *gpadlheader;
 593         unsigned long flags;
 594
 595         gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
 596
 597         /*
 598          * Find the establish msg, copy the result and signal/unblock the wait
 599          * event
 600          */
 601         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 602
 603         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 604                                 msglistentry) {
 605                 requestheader =
 606                         (struct vmbus_channel_message_header *)msginfo->msg;
 607
 608                 if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
 609                         gpadlheader =
 610                         (struct vmbus_channel_gpadl_header *)requestheader;
 611
 612                         if ((gpadlcreated->child_relid ==
 613                              gpadlheader->child_relid) &&
 614                             (gpadlcreated->gpadl == gpadlheader->gpadl)) {
 615                                 memcpy(&msginfo->response.gpadl_created,
 616                                        gpadlcreated,
 617                                        sizeof(
 618                                         struct vmbus_channel_gpadl_created));
 619                                 complete(&msginfo->waitevent);
 620                                 break;
 621                         }
 622                 }
 623         }
 624         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 625 }
 626
 627 /*
 628  * vmbus_ongpadl_torndown - GPADL torndown handler.
 629  *
 630  * This is invoked when we received a response to our gpadl teardown request.
 631  * Find the matching request, copy the response and signal the requesting
 632  * thread.
 633  */
 634 static void vmbus_ongpadl_torndown(
 635                         struct vmbus_channel_message_header *hdr)
 636 {
 637         struct vmbus_channel_gpadl_torndown *gpadl_torndown;
 638         struct vmbus_channel_msginfo *msginfo;
 639         struct vmbus_channel_message_header *requestheader;
 640         struct vmbus_channel_gpadl_teardown *gpadl_teardown;
 641         unsigned long flags;
 642
 643         gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
 644
 645         /*
 646          * Find the open msg, copy the result and signal/unblock the wait event
 647          */
 648         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 649
 650         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 651                                 msglistentry) {
 652                 requestheader =
 653                         (struct vmbus_channel_message_header *)msginfo->msg;
 654
 655                 if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
 656                         gpadl_teardown =
 657                         (struct vmbus_channel_gpadl_teardown *)requestheader;
 658
 659                         if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
 660                                 memcpy(&msginfo->response.gpadl_torndown,
 661                                        gpadl_torndown,
 662                                        sizeof(
 663                                         struct vmbus_channel_gpadl_torndown));
 664                                 complete(&msginfo->waitevent);
 665                                 break;
 666                         }
 667                 }
 668         }
 669         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 670 }
 671
 672 /*
 673  * vmbus_onversion_response - Version response handler
 674  *
 675  * This is invoked when we received a response to our initiate contact request.
 676  * Find the matching request, copy the response and signal the requesting
 677  * thread.
 678  */
 679 static void vmbus_onversion_response(
 680                 struct vmbus_channel_message_header *hdr)
 681 {
 682         struct vmbus_channel_msginfo *msginfo;
 683         struct vmbus_channel_message_header *requestheader;
 684         struct vmbus_channel_version_response *version_response;
 685         unsigned long flags;
 686
 687         version_response = (struct vmbus_channel_version_response *)hdr;
 688         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 689
 690         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 691                                 msglistentry) {
 692                 requestheader =
 693                         (struct vmbus_channel_message_header *)msginfo->msg;
 694
 695                 if (requestheader->msgtype ==
 696                     CHANNELMSG_INITIATE_CONTACT) {
 697                         memcpy(&msginfo->response.version_response,
 698                               version_response,
 699                               sizeof(struct vmbus_channel_version_response));
 700                         complete(&msginfo->waitevent);
 701                 }
 702         }
 703         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 704 }
 705
 706 /* Channel message dispatch table */
 707 static struct vmbus_channel_message_table_entry
 708         channel_message_table[CHANNELMSG_COUNT] = {
 709         {CHANNELMSG_INVALID,                    NULL},
 710         {CHANNELMSG_OFFERCHANNEL,               vmbus_onoffer},
 711         {CHANNELMSG_RESCIND_CHANNELOFFER,       vmbus_onoffer_rescind},
 712         {CHANNELMSG_REQUESTOFFERS,              NULL},
 713         {CHANNELMSG_ALLOFFERS_DELIVERED,        vmbus_onoffers_delivered},
 714         {CHANNELMSG_OPENCHANNEL,                NULL},
 715         {CHANNELMSG_OPENCHANNEL_RESULT, vmbus_onopen_result},
 716         {CHANNELMSG_CLOSECHANNEL,               NULL},
 717         {CHANNELMSG_GPADL_HEADER,               NULL},
 718         {CHANNELMSG_GPADL_BODY,         NULL},
 719         {CHANNELMSG_GPADL_CREATED,              vmbus_ongpadl_created},
 720         {CHANNELMSG_GPADL_TEARDOWN,             NULL},
 721         {CHANNELMSG_GPADL_TORNDOWN,             vmbus_ongpadl_torndown},
 722         {CHANNELMSG_RELID_RELEASED,             NULL},
 723         {CHANNELMSG_INITIATE_CONTACT,           NULL},
 724         {CHANNELMSG_VERSION_RESPONSE,           vmbus_onversion_response},
 725         {CHANNELMSG_UNLOAD,                     NULL},
 726 };
 727
 728 /*
 729  * vmbus_onmessage - Handler for channel protocol messages.
 730  *
 731  * This is invoked in the vmbus worker thread context.
 732  */
 733 void vmbus_onmessage(void *context)
 734 {
 735         struct hv_message *msg = context;
 736         struct vmbus_channel_message_header *hdr;
 737         int size;
 738
 739         hdr = (struct vmbus_channel_message_header *)msg->u.payload;
 740         size = msg->header.payload_size;
 741
 742         if (hdr->msgtype >= CHANNELMSG_COUNT) {
 743                 pr_err("Received invalid channel message type %d size %d\n",
 744                            hdr->msgtype, size);
 745                 print_hex_dump_bytes("", DUMP_PREFIX_NONE,
 746                                      (unsigned char *)msg->u.payload, size);
 747                 return;
 748         }
 749
 750         if (channel_message_table[hdr->msgtype].message_handler)
 751                 channel_message_table[hdr->msgtype].message_handler(hdr);
 752         else
 753                 pr_err("Unhandled channel message type %d\n", hdr->msgtype);
 754 }
 755
 756 /*
 757  * vmbus_request_offers - Send a request to get all our pending offers.
 758  */
 759 int vmbus_request_offers(void)
 760 {
 761         struct vmbus_channel_message_header *msg;
 762         struct vmbus_channel_msginfo *msginfo;
 763         int ret, t;
 764
 765         msginfo = kmalloc(sizeof(*msginfo) +
 766                           sizeof(struct vmbus_channel_message_header),
 767                           GFP_KERNEL);
 768         if (!msginfo)
 769                 return -ENOMEM;
 770
 771         init_completion(&msginfo->waitevent);
 772
 773         msg = (struct vmbus_channel_message_header *)msginfo->msg;
 774
 775         msg->msgtype = CHANNELMSG_REQUESTOFFERS;
 776
 777
 778         ret = vmbus_post_msg(msg,
 779                                sizeof(struct vmbus_channel_message_header));
 780         if (ret != 0) {
 781                 pr_err("Unable to request offers - %d\n", ret);
 782
 783                 goto cleanup;
 784         }
 785
 786         t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
 787         if (t == 0) {
 788                 ret = -ETIMEDOUT;
 789                 goto cleanup;
 790         }
 791
 792
 793
 794 cleanup:
 795         kfree(msginfo);
 796
 797         return ret;
 798 }
 799
 800 /*
 801  * Retrieve the (sub) channel on which to send an outgoing request.
 802  * When a primary channel has multiple sub-channels, we choose a
 803  * channel whose VCPU binding is closest to the VCPU on which
 804  * this call is being made.
 805  */
 806 struct vmbus_channel *vmbus_get_outgoing_channel(struct vmbus_channel *primary)
 807 {
 808         struct list_head *cur, *tmp;
 809         int cur_cpu = hv_context.vp_index[smp_processor_id()];
 810         struct vmbus_channel *cur_channel;
 811         struct vmbus_channel *outgoing_channel = primary;
 812         int cpu_distance, new_cpu_distance;
 813
 814         if (list_empty(&primary->sc_list))
 815                 return outgoing_channel;
 816
 817         list_for_each_safe(cur, tmp, &primary->sc_list) {
 818                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 819                 if (cur_channel->state != CHANNEL_OPENED_STATE)
 820                         continue;
 821
 822                 if (cur_channel->target_vp == cur_cpu)
 823                         return cur_channel;
 824
 825                 cpu_distance = ((outgoing_channel->target_vp > cur_cpu) ?
 826                                 (outgoing_channel->target_vp - cur_cpu) :
 827                                 (cur_cpu - outgoing_channel->target_vp));
 828
 829                 new_cpu_distance = ((cur_channel->target_vp > cur_cpu) ?
 830                                 (cur_channel->target_vp - cur_cpu) :
 831                                 (cur_cpu - cur_channel->target_vp));
 832
 833                 if (cpu_distance < new_cpu_distance)
 834                         continue;
 835
 836                 outgoing_channel = cur_channel;
 837         }
 838
 839         return outgoing_channel;
 840 }
 841 EXPORT_SYMBOL_GPL(vmbus_get_outgoing_channel);
 842
 843 static void invoke_sc_cb(struct vmbus_channel *primary_channel)
 844 {
 845         struct list_head *cur, *tmp;
 846         struct vmbus_channel *cur_channel;
 847
 848         if (primary_channel->sc_creation_callback == NULL)
 849                 return;
 850
 851         list_for_each_safe(cur, tmp, &primary_channel->sc_list) {
 852                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 853
 854                 primary_channel->sc_creation_callback(cur_channel);
 855         }
 856 }
 857
 858 void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
 859                                 void (*sc_cr_cb)(struct vmbus_channel *new_sc))
 860 {
 861         primary_channel->sc_creation_callback = sc_cr_cb;
 862 }
 863 EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
 864
 865 bool vmbus_are_subchannels_present(struct vmbus_channel *primary)
 866 {
 867         bool ret;
 868
 869         ret = !list_empty(&primary->sc_list);
 870
 871         if (ret) {
 872                 /*
 873                  * Invoke the callback on sub-channel creation.
 874                  * This will present a uniform interface to the
 875                  * clients.
 876                  */
 877                 invoke_sc_cb(primary);
 878         }
 879
 880         return ret;
 881 }
 882 EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present);