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         struct device *dev;
 220
 221         if (channel->device_obj) {
 222                 dev = get_device(&channel->device_obj->device);
 223                 if (dev) {
 224                         vmbus_device_unregister(channel->device_obj);
 225                         put_device(dev);
 226                 }
 227         }
 228
 229         memset(&msg, 0, sizeof(struct vmbus_channel_relid_released));
 230         msg.child_relid = channel->offermsg.child_relid;
 231         msg.header.msgtype = CHANNELMSG_RELID_RELEASED;
 232         vmbus_post_msg(&msg, sizeof(struct vmbus_channel_relid_released));
 233
 234         if (channel->target_cpu != get_cpu()) {
 235                 put_cpu();
 236                 smp_call_function_single(channel->target_cpu,
 237                                          percpu_channel_deq, channel, true);
 238         } else {
 239                 percpu_channel_deq(channel);
 240                 put_cpu();
 241         }
 242
 243         if (channel->primary_channel == NULL) {
 244                 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 245                 list_del(&channel->listentry);
 246                 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 247         } else {
 248                 primary_channel = channel->primary_channel;
 249                 spin_lock_irqsave(&primary_channel->sc_lock, flags);
 250                 list_del(&channel->sc_list);
 251                 spin_unlock_irqrestore(&primary_channel->sc_lock, flags);
 252         }
 253         free_channel(channel);
 254 }
 255
 256 void vmbus_free_channels(void)
 257 {
 258         struct vmbus_channel *channel;
 259
 260         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 261                 vmbus_device_unregister(channel->device_obj);
 262                 kfree(channel->device_obj);
 263                 free_channel(channel);
 264         }
 265 }
 266
 267 /*
 268  * vmbus_process_offer - Process the offer by creating a channel/device
 269  * associated with this offer
 270  */
 271 static void vmbus_process_offer(struct work_struct *work)
 272 {
 273         struct vmbus_channel *newchannel = container_of(work,
 274                                                         struct vmbus_channel,
 275                                                         work);
 276         struct vmbus_channel *channel;
 277         bool fnew = true;
 278         bool enq = false;
 279         int ret;
 280         unsigned long flags;
 281
 282         /* The next possible work is rescind handling */
 283         INIT_WORK(&newchannel->work, vmbus_process_rescind_offer);
 284
 285         /* Make sure this is a new offer */
 286         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 287
 288         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 289                 if (!uuid_le_cmp(channel->offermsg.offer.if_type,
 290                         newchannel->offermsg.offer.if_type) &&
 291                         !uuid_le_cmp(channel->offermsg.offer.if_instance,
 292                                 newchannel->offermsg.offer.if_instance)) {
 293                         fnew = false;
 294                         break;
 295                 }
 296         }
 297
 298         if (fnew) {
 299                 list_add_tail(&newchannel->listentry,
 300                               &vmbus_connection.chn_list);
 301                 enq = true;
 302         }
 303
 304         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 305
 306         if (enq) {
 307                 if (newchannel->target_cpu != get_cpu()) {
 308                         put_cpu();
 309                         smp_call_function_single(newchannel->target_cpu,
 310                                                  percpu_channel_enq,
 311                                                  newchannel, true);
 312                 } else {
 313                         percpu_channel_enq(newchannel);
 314                         put_cpu();
 315                 }
 316         }
 317         if (!fnew) {
 318                 /*
 319                  * Check to see if this is a sub-channel.
 320                  */
 321                 if (newchannel->offermsg.offer.sub_channel_index != 0) {
 322                         /*
 323                          * Process the sub-channel.
 324                          */
 325                         newchannel->primary_channel = channel;
 326                         spin_lock_irqsave(&channel->sc_lock, flags);
 327                         list_add_tail(&newchannel->sc_list, &channel->sc_list);
 328                         spin_unlock_irqrestore(&channel->sc_lock, flags);
 329
 330                         if (newchannel->target_cpu != get_cpu()) {
 331                                 put_cpu();
 332                                 smp_call_function_single(newchannel->target_cpu,
 333                                                          percpu_channel_enq,
 334                                                          newchannel, true);
 335                         } else {
 336                                 percpu_channel_enq(newchannel);
 337                                 put_cpu();
 338                         }
 339
 340                         newchannel->state = CHANNEL_OPEN_STATE;
 341                         if (channel->sc_creation_callback != NULL)
 342                                 channel->sc_creation_callback(newchannel);
 343
 344                         return;
 345                 }
 346
 347                 free_channel(newchannel);
 348                 return;
 349         }
 350
 351         /*
 352          * This state is used to indicate a successful open
 353          * so that when we do close the channel normally, we
 354          * can cleanup properly
 355          */
 356         newchannel->state = CHANNEL_OPEN_STATE;
 357
 358         /*
 359          * Start the process of binding this offer to the driver
 360          * We need to set the DeviceObject field before calling
 361          * vmbus_child_dev_add()
 362          */
 363         newchannel->device_obj = vmbus_device_create(
 364                 &newchannel->offermsg.offer.if_type,
 365                 &newchannel->offermsg.offer.if_instance,
 366                 newchannel);
 367
 368         /*
 369          * Add the new device to the bus. This will kick off device-driver
 370          * binding which eventually invokes the device driver's AddDevice()
 371          * method.
 372          */
 373         ret = vmbus_device_register(newchannel->device_obj);
 374         if (ret != 0) {
 375                 pr_err("unable to add child device object (relid %d)\n",
 376                            newchannel->offermsg.child_relid);
 377
 378                 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 379                 list_del(&newchannel->listentry);
 380                 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 381                 kfree(newchannel->device_obj);
 382
 383                 free_channel(newchannel);
 384         }
 385 }
 386
 387 enum {
 388         IDE = 0,
 389         SCSI,
 390         NIC,
 391         MAX_PERF_CHN,
 392 };
 393
 394 /*
 395  * This is an array of device_ids (device types) that are performance critical.
 396  * We attempt to distribute the interrupt load for these devices across
 397  * all available CPUs.
 398  */
 399 static const struct hv_vmbus_device_id hp_devs[] = {
 400         /* IDE */
 401         { HV_IDE_GUID, },
 402         /* Storage - SCSI */
 403         { HV_SCSI_GUID, },
 404         /* Network */
 405         { HV_NIC_GUID, },
 406 };
 407
 408
 409 /*
 410  * We use this state to statically distribute the channel interrupt load.
 411  */
 412 static u32  next_vp;
 413
 414 /*
 415  * Starting with Win8, we can statically distribute the incoming
 416  * channel interrupt load by binding a channel to VCPU. We
 417  * implement here a simple round robin scheme for distributing
 418  * the interrupt load.
 419  * We will bind channels that are not performance critical to cpu 0 and
 420  * performance critical channels (IDE, SCSI and Network) will be uniformly
 421  * distributed across all available CPUs.
 422  */
 423 static void init_vp_index(struct vmbus_channel *channel, const uuid_le *type_guid)
 424 {
 425         u32 cur_cpu;
 426         int i;
 427         bool perf_chn = false;
 428         u32 max_cpus = num_online_cpus();
 429
 430         for (i = IDE; i < MAX_PERF_CHN; i++) {
 431                 if (!memcmp(type_guid->b, hp_devs[i].guid,
 432                                  sizeof(uuid_le))) {
 433                         perf_chn = true;
 434                         break;
 435                 }
 436         }
 437         if ((vmbus_proto_version == VERSION_WS2008) ||
 438             (vmbus_proto_version == VERSION_WIN7) || (!perf_chn)) {
 439                 /*
 440                  * Prior to win8, all channel interrupts are
 441                  * delivered on cpu 0.
 442                  * Also if the channel is not a performance critical
 443                  * channel, bind it to cpu 0.
 444                  */
 445                 channel->target_cpu = 0;
 446                 channel->target_vp = 0;
 447                 return;
 448         }
 449         cur_cpu = (++next_vp % max_cpus);
 450         channel->target_cpu = cur_cpu;
 451         channel->target_vp = hv_context.vp_index[cur_cpu];
 452 }
 453
 454 /*
 455  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 456  *
 457  */
 458 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 459 {
 460         struct vmbus_channel_offer_channel *offer;
 461         struct vmbus_channel *newchannel;
 462
 463         offer = (struct vmbus_channel_offer_channel *)hdr;
 464
 465         /* Allocate the channel object and save this offer. */
 466         newchannel = alloc_channel();
 467         if (!newchannel) {
 468                 pr_err("Unable to allocate channel object\n");
 469                 return;
 470         }
 471
 472         /*
 473          * By default we setup state to enable batched
 474          * reading. A specific service can choose to
 475          * disable this prior to opening the channel.
 476          */
 477         newchannel->batched_reading = true;
 478
 479         /*
 480          * Setup state for signalling the host.
 481          */
 482         newchannel->sig_event = (struct hv_input_signal_event *)
 483                                 (ALIGN((unsigned long)
 484                                 &newchannel->sig_buf,
 485                                 HV_HYPERCALL_PARAM_ALIGN));
 486
 487         newchannel->sig_event->connectionid.asu32 = 0;
 488         newchannel->sig_event->connectionid.u.id = VMBUS_EVENT_CONNECTION_ID;
 489         newchannel->sig_event->flag_number = 0;
 490         newchannel->sig_event->rsvdz = 0;
 491
 492         if (vmbus_proto_version != VERSION_WS2008) {
 493                 newchannel->is_dedicated_interrupt =
 494                                 (offer->is_dedicated_interrupt != 0);
 495                 newchannel->sig_event->connectionid.u.id =
 496                                 offer->connection_id;
 497         }
 498
 499         init_vp_index(newchannel, &offer->offer.if_type);
 500
 501         memcpy(&newchannel->offermsg, offer,
 502                sizeof(struct vmbus_channel_offer_channel));
 503         newchannel->monitor_grp = (u8)offer->monitorid / 32;
 504         newchannel->monitor_bit = (u8)offer->monitorid % 32;
 505
 506         INIT_WORK(&newchannel->work, vmbus_process_offer);
 507         queue_work(newchannel->controlwq, &newchannel->work);
 508 }
 509
 510 /*
 511  * vmbus_onoffer_rescind - Rescind offer handler.
 512  *
 513  * We queue a work item to process this offer synchronously
 514  */
 515 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 516 {
 517         struct vmbus_channel_rescind_offer *rescind;
 518         struct vmbus_channel *channel;
 519
 520         rescind = (struct vmbus_channel_rescind_offer *)hdr;
 521         channel = relid2channel(rescind->child_relid);
 522
 523         if (channel == NULL)
 524                 /* Just return here, no channel found */
 525                 return;
 526
 527         channel->rescind = true;
 528
 529         /* work is initialized for vmbus_process_rescind_offer() from
 530          * vmbus_process_offer() where the channel got created */
 531         queue_work(channel->controlwq, &channel->work);
 532 }
 533
 534 /*
 535  * vmbus_onoffers_delivered -
 536  * This is invoked when all offers have been delivered.
 537  *
 538  * Nothing to do here.
 539  */
 540 static void vmbus_onoffers_delivered(
 541                         struct vmbus_channel_message_header *hdr)
 542 {
 543 }
 544
 545 /*
 546  * vmbus_onopen_result - Open result handler.
 547  *
 548  * This is invoked when we received a response to our channel open request.
 549  * Find the matching request, copy the response and signal the requesting
 550  * thread.
 551  */
 552 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
 553 {
 554         struct vmbus_channel_open_result *result;
 555         struct vmbus_channel_msginfo *msginfo;
 556         struct vmbus_channel_message_header *requestheader;
 557         struct vmbus_channel_open_channel *openmsg;
 558         unsigned long flags;
 559
 560         result = (struct vmbus_channel_open_result *)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_OPENCHANNEL) {
 573                         openmsg =
 574                         (struct vmbus_channel_open_channel *)msginfo->msg;
 575                         if (openmsg->child_relid == result->child_relid &&
 576                             openmsg->openid == result->openid) {
 577                                 memcpy(&msginfo->response.open_result,
 578                                        result,
 579                                        sizeof(
 580                                         struct vmbus_channel_open_result));
 581                                 complete(&msginfo->waitevent);
 582                                 break;
 583                         }
 584                 }
 585         }
 586         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 587 }
 588
 589 /*
 590  * vmbus_ongpadl_created - GPADL created handler.
 591  *
 592  * This is invoked when we received a response to our gpadl create request.
 593  * Find the matching request, copy the response and signal the requesting
 594  * thread.
 595  */
 596 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
 597 {
 598         struct vmbus_channel_gpadl_created *gpadlcreated;
 599         struct vmbus_channel_msginfo *msginfo;
 600         struct vmbus_channel_message_header *requestheader;
 601         struct vmbus_channel_gpadl_header *gpadlheader;
 602         unsigned long flags;
 603
 604         gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
 605
 606         /*
 607          * Find the establish msg, copy the result and signal/unblock the wait
 608          * event
 609          */
 610         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 611
 612         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 613                                 msglistentry) {
 614                 requestheader =
 615                         (struct vmbus_channel_message_header *)msginfo->msg;
 616
 617                 if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
 618                         gpadlheader =
 619                         (struct vmbus_channel_gpadl_header *)requestheader;
 620
 621                         if ((gpadlcreated->child_relid ==
 622                              gpadlheader->child_relid) &&
 623                             (gpadlcreated->gpadl == gpadlheader->gpadl)) {
 624                                 memcpy(&msginfo->response.gpadl_created,
 625                                        gpadlcreated,
 626                                        sizeof(
 627                                         struct vmbus_channel_gpadl_created));
 628                                 complete(&msginfo->waitevent);
 629                                 break;
 630                         }
 631                 }
 632         }
 633         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 634 }
 635
 636 /*
 637  * vmbus_ongpadl_torndown - GPADL torndown handler.
 638  *
 639  * This is invoked when we received a response to our gpadl teardown request.
 640  * Find the matching request, copy the response and signal the requesting
 641  * thread.
 642  */
 643 static void vmbus_ongpadl_torndown(
 644                         struct vmbus_channel_message_header *hdr)
 645 {
 646         struct vmbus_channel_gpadl_torndown *gpadl_torndown;
 647         struct vmbus_channel_msginfo *msginfo;
 648         struct vmbus_channel_message_header *requestheader;
 649         struct vmbus_channel_gpadl_teardown *gpadl_teardown;
 650         unsigned long flags;
 651
 652         gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
 653
 654         /*
 655          * Find the open msg, copy the result and signal/unblock the wait event
 656          */
 657         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 658
 659         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 660                                 msglistentry) {
 661                 requestheader =
 662                         (struct vmbus_channel_message_header *)msginfo->msg;
 663
 664                 if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
 665                         gpadl_teardown =
 666                         (struct vmbus_channel_gpadl_teardown *)requestheader;
 667
 668                         if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
 669                                 memcpy(&msginfo->response.gpadl_torndown,
 670                                        gpadl_torndown,
 671                                        sizeof(
 672                                         struct vmbus_channel_gpadl_torndown));
 673                                 complete(&msginfo->waitevent);
 674                                 break;
 675                         }
 676                 }
 677         }
 678         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 679 }
 680
 681 /*
 682  * vmbus_onversion_response - Version response handler
 683  *
 684  * This is invoked when we received a response to our initiate contact request.
 685  * Find the matching request, copy the response and signal the requesting
 686  * thread.
 687  */
 688 static void vmbus_onversion_response(
 689                 struct vmbus_channel_message_header *hdr)
 690 {
 691         struct vmbus_channel_msginfo *msginfo;
 692         struct vmbus_channel_message_header *requestheader;
 693         struct vmbus_channel_version_response *version_response;
 694         unsigned long flags;
 695
 696         version_response = (struct vmbus_channel_version_response *)hdr;
 697         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 698
 699         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 700                                 msglistentry) {
 701                 requestheader =
 702                         (struct vmbus_channel_message_header *)msginfo->msg;
 703
 704                 if (requestheader->msgtype ==
 705                     CHANNELMSG_INITIATE_CONTACT) {
 706                         memcpy(&msginfo->response.version_response,
 707                               version_response,
 708                               sizeof(struct vmbus_channel_version_response));
 709                         complete(&msginfo->waitevent);
 710                 }
 711         }
 712         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 713 }
 714
 715 /* Channel message dispatch table */
 716 static struct vmbus_channel_message_table_entry
 717         channel_message_table[CHANNELMSG_COUNT] = {
 718         {CHANNELMSG_INVALID,                    NULL},
 719         {CHANNELMSG_OFFERCHANNEL,               vmbus_onoffer},
 720         {CHANNELMSG_RESCIND_CHANNELOFFER,       vmbus_onoffer_rescind},
 721         {CHANNELMSG_REQUESTOFFERS,              NULL},
 722         {CHANNELMSG_ALLOFFERS_DELIVERED,        vmbus_onoffers_delivered},
 723         {CHANNELMSG_OPENCHANNEL,                NULL},
 724         {CHANNELMSG_OPENCHANNEL_RESULT, vmbus_onopen_result},
 725         {CHANNELMSG_CLOSECHANNEL,               NULL},
 726         {CHANNELMSG_GPADL_HEADER,               NULL},
 727         {CHANNELMSG_GPADL_BODY,         NULL},
 728         {CHANNELMSG_GPADL_CREATED,              vmbus_ongpadl_created},
 729         {CHANNELMSG_GPADL_TEARDOWN,             NULL},
 730         {CHANNELMSG_GPADL_TORNDOWN,             vmbus_ongpadl_torndown},
 731         {CHANNELMSG_RELID_RELEASED,             NULL},
 732         {CHANNELMSG_INITIATE_CONTACT,           NULL},
 733         {CHANNELMSG_VERSION_RESPONSE,           vmbus_onversion_response},
 734         {CHANNELMSG_UNLOAD,                     NULL},
 735 };
 736
 737 /*
 738  * vmbus_onmessage - Handler for channel protocol messages.
 739  *
 740  * This is invoked in the vmbus worker thread context.
 741  */
 742 void vmbus_onmessage(void *context)
 743 {
 744         struct hv_message *msg = context;
 745         struct vmbus_channel_message_header *hdr;
 746         int size;
 747
 748         hdr = (struct vmbus_channel_message_header *)msg->u.payload;
 749         size = msg->header.payload_size;
 750
 751         if (hdr->msgtype >= CHANNELMSG_COUNT) {
 752                 pr_err("Received invalid channel message type %d size %d\n",
 753                            hdr->msgtype, size);
 754                 print_hex_dump_bytes("", DUMP_PREFIX_NONE,
 755                                      (unsigned char *)msg->u.payload, size);
 756                 return;
 757         }
 758
 759         if (channel_message_table[hdr->msgtype].message_handler)
 760                 channel_message_table[hdr->msgtype].message_handler(hdr);
 761         else
 762                 pr_err("Unhandled channel message type %d\n", hdr->msgtype);
 763 }
 764
 765 /*
 766  * vmbus_request_offers - Send a request to get all our pending offers.
 767  */
 768 int vmbus_request_offers(void)
 769 {
 770         struct vmbus_channel_message_header *msg;
 771         struct vmbus_channel_msginfo *msginfo;
 772         int ret, t;
 773
 774         msginfo = kmalloc(sizeof(*msginfo) +
 775                           sizeof(struct vmbus_channel_message_header),
 776                           GFP_KERNEL);
 777         if (!msginfo)
 778                 return -ENOMEM;
 779
 780         init_completion(&msginfo->waitevent);
 781
 782         msg = (struct vmbus_channel_message_header *)msginfo->msg;
 783
 784         msg->msgtype = CHANNELMSG_REQUESTOFFERS;
 785
 786
 787         ret = vmbus_post_msg(msg,
 788                                sizeof(struct vmbus_channel_message_header));
 789         if (ret != 0) {
 790                 pr_err("Unable to request offers - %d\n", ret);
 791
 792                 goto cleanup;
 793         }
 794
 795         t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
 796         if (t == 0) {
 797                 ret = -ETIMEDOUT;
 798                 goto cleanup;
 799         }
 800
 801
 802
 803 cleanup:
 804         kfree(msginfo);
 805
 806         return ret;
 807 }
 808
 809 /*
 810  * Retrieve the (sub) channel on which to send an outgoing request.
 811  * When a primary channel has multiple sub-channels, we choose a
 812  * channel whose VCPU binding is closest to the VCPU on which
 813  * this call is being made.
 814  */
 815 struct vmbus_channel *vmbus_get_outgoing_channel(struct vmbus_channel *primary)
 816 {
 817         struct list_head *cur, *tmp;
 818         int cur_cpu = hv_context.vp_index[smp_processor_id()];
 819         struct vmbus_channel *cur_channel;
 820         struct vmbus_channel *outgoing_channel = primary;
 821         int cpu_distance, new_cpu_distance;
 822
 823         if (list_empty(&primary->sc_list))
 824                 return outgoing_channel;
 825
 826         list_for_each_safe(cur, tmp, &primary->sc_list) {
 827                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 828                 if (cur_channel->state != CHANNEL_OPENED_STATE)
 829                         continue;
 830
 831                 if (cur_channel->target_vp == cur_cpu)
 832                         return cur_channel;
 833
 834                 cpu_distance = ((outgoing_channel->target_vp > cur_cpu) ?
 835                                 (outgoing_channel->target_vp - cur_cpu) :
 836                                 (cur_cpu - outgoing_channel->target_vp));
 837
 838                 new_cpu_distance = ((cur_channel->target_vp > cur_cpu) ?
 839                                 (cur_channel->target_vp - cur_cpu) :
 840                                 (cur_cpu - cur_channel->target_vp));
 841
 842                 if (cpu_distance < new_cpu_distance)
 843                         continue;
 844
 845                 outgoing_channel = cur_channel;
 846         }
 847
 848         return outgoing_channel;
 849 }
 850 EXPORT_SYMBOL_GPL(vmbus_get_outgoing_channel);
 851
 852 static void invoke_sc_cb(struct vmbus_channel *primary_channel)
 853 {
 854         struct list_head *cur, *tmp;
 855         struct vmbus_channel *cur_channel;
 856
 857         if (primary_channel->sc_creation_callback == NULL)
 858                 return;
 859
 860         list_for_each_safe(cur, tmp, &primary_channel->sc_list) {
 861                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 862
 863                 primary_channel->sc_creation_callback(cur_channel);
 864         }
 865 }
 866
 867 void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
 868                                 void (*sc_cr_cb)(struct vmbus_channel *new_sc))
 869 {
 870         primary_channel->sc_creation_callback = sc_cr_cb;
 871 }
 872 EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
 873
 874 bool vmbus_are_subchannels_present(struct vmbus_channel *primary)
 875 {
 876         bool ret;
 877
 878         ret = !list_empty(&primary->sc_list);
 879
 880         if (ret) {
 881                 /*
 882                  * Invoke the callback on sub-channel creation.
 883                  * This will present a uniform interface to the
 884                  * clients.
 885                  */
 886                 invoke_sc_cb(primary);
 887         }
 888
 889         return ret;
 890 }
 891 EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present);