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->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->lock, flags);
 250                 list_del(&channel->sc_list);
 251                 spin_unlock_irqrestore(&primary_channel->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         /* Make sure this is a new offer */
 283         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 284
 285         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 286                 if (!uuid_le_cmp(channel->offermsg.offer.if_type,
 287                         newchannel->offermsg.offer.if_type) &&
 288                         !uuid_le_cmp(channel->offermsg.offer.if_instance,
 289                                 newchannel->offermsg.offer.if_instance)) {
 290                         fnew = false;
 291                         break;
 292                 }
 293         }
 294
 295         if (fnew) {
 296                 list_add_tail(&newchannel->listentry,
 297                               &vmbus_connection.chn_list);
 298                 enq = true;
 299         }
 300
 301         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 302
 303         if (enq) {
 304                 if (newchannel->target_cpu != get_cpu()) {
 305                         put_cpu();
 306                         smp_call_function_single(newchannel->target_cpu,
 307                                                  percpu_channel_enq,
 308                                                  newchannel, true);
 309                 } else {
 310                         percpu_channel_enq(newchannel);
 311                         put_cpu();
 312                 }
 313         }
 314         if (!fnew) {
 315                 /*
 316                  * Check to see if this is a sub-channel.
 317                  */
 318                 if (newchannel->offermsg.offer.sub_channel_index != 0) {
 319                         /*
 320                          * Process the sub-channel.
 321                          */
 322                         newchannel->primary_channel = channel;
 323                         spin_lock_irqsave(&channel->lock, flags);
 324                         list_add_tail(&newchannel->sc_list, &channel->sc_list);
 325                         spin_unlock_irqrestore(&channel->lock, flags);
 326
 327                         if (newchannel->target_cpu != get_cpu()) {
 328                                 put_cpu();
 329                                 smp_call_function_single(newchannel->target_cpu,
 330                                                          percpu_channel_enq,
 331                                                          newchannel, true);
 332                         } else {
 333                                 percpu_channel_enq(newchannel);
 334                                 put_cpu();
 335                         }
 336
 337                         newchannel->state = CHANNEL_OPEN_STATE;
 338                         if (channel->sc_creation_callback != NULL)
 339                                 channel->sc_creation_callback(newchannel);
 340
 341                         goto done_init_rescind;
 342                 }
 343
 344                 goto err_free_chan;
 345         }
 346
 347         /*
 348          * This state is used to indicate a successful open
 349          * so that when we do close the channel normally, we
 350          * can cleanup properly
 351          */
 352         newchannel->state = CHANNEL_OPEN_STATE;
 353
 354         /*
 355          * Start the process of binding this offer to the driver
 356          * We need to set the DeviceObject field before calling
 357          * vmbus_child_dev_add()
 358          */
 359         newchannel->device_obj = vmbus_device_create(
 360                 &newchannel->offermsg.offer.if_type,
 361                 &newchannel->offermsg.offer.if_instance,
 362                 newchannel);
 363         if (!newchannel->device_obj)
 364                 goto err_free_chan;
 365
 366         /*
 367          * Add the new device to the bus. This will kick off device-driver
 368          * binding which eventually invokes the device driver's AddDevice()
 369          * method.
 370          */
 371         ret = vmbus_device_register(newchannel->device_obj);
 372         if (ret != 0) {
 373                 pr_err("unable to add child device object (relid %d)\n",
 374                            newchannel->offermsg.child_relid);
 375
 376                 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 377                 list_del(&newchannel->listentry);
 378                 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 379                 kfree(newchannel->device_obj);
 380                 goto err_free_chan;
 381         }
 382 done_init_rescind:
 383         spin_lock_irqsave(&newchannel->lock, flags);
 384         /* The next possible work is rescind handling */
 385         INIT_WORK(&newchannel->work, vmbus_process_rescind_offer);
 386         /* Check if rescind offer was already received */
 387         if (newchannel->rescind)
 388                 queue_work(newchannel->controlwq, &newchannel->work);
 389         spin_unlock_irqrestore(&newchannel->lock, flags);
 390         return;
 391 err_free_chan:
 392         free_channel(newchannel);
 393 }
 394
 395 enum {
 396         IDE = 0,
 397         SCSI,
 398         NIC,
 399         MAX_PERF_CHN,
 400 };
 401
 402 /*
 403  * This is an array of device_ids (device types) that are performance critical.
 404  * We attempt to distribute the interrupt load for these devices across
 405  * all available CPUs.
 406  */
 407 static const struct hv_vmbus_device_id hp_devs[] = {
 408         /* IDE */
 409         { HV_IDE_GUID, },
 410         /* Storage - SCSI */
 411         { HV_SCSI_GUID, },
 412         /* Network */
 413         { HV_NIC_GUID, },
 414 };
 415
 416
 417 /*
 418  * We use this state to statically distribute the channel interrupt load.
 419  */
 420 static u32  next_vp;
 421
 422 /*
 423  * Starting with Win8, we can statically distribute the incoming
 424  * channel interrupt load by binding a channel to VCPU. We
 425  * implement here a simple round robin scheme for distributing
 426  * the interrupt load.
 427  * We will bind channels that are not performance critical to cpu 0 and
 428  * performance critical channels (IDE, SCSI and Network) will be uniformly
 429  * distributed across all available CPUs.
 430  */
 431 static void init_vp_index(struct vmbus_channel *channel, const uuid_le *type_guid)
 432 {
 433         u32 cur_cpu;
 434         int i;
 435         bool perf_chn = false;
 436         u32 max_cpus = num_online_cpus();
 437
 438         for (i = IDE; i < MAX_PERF_CHN; i++) {
 439                 if (!memcmp(type_guid->b, hp_devs[i].guid,
 440                                  sizeof(uuid_le))) {
 441                         perf_chn = true;
 442                         break;
 443                 }
 444         }
 445         if ((vmbus_proto_version == VERSION_WS2008) ||
 446             (vmbus_proto_version == VERSION_WIN7) || (!perf_chn)) {
 447                 /*
 448                  * Prior to win8, all channel interrupts are
 449                  * delivered on cpu 0.
 450                  * Also if the channel is not a performance critical
 451                  * channel, bind it to cpu 0.
 452                  */
 453                 channel->target_cpu = 0;
 454                 channel->target_vp = 0;
 455                 return;
 456         }
 457         cur_cpu = (++next_vp % max_cpus);
 458         channel->target_cpu = cur_cpu;
 459         channel->target_vp = hv_context.vp_index[cur_cpu];
 460 }
 461
 462 /*
 463  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 464  *
 465  */
 466 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 467 {
 468         struct vmbus_channel_offer_channel *offer;
 469         struct vmbus_channel *newchannel;
 470
 471         offer = (struct vmbus_channel_offer_channel *)hdr;
 472
 473         /* Allocate the channel object and save this offer. */
 474         newchannel = alloc_channel();
 475         if (!newchannel) {
 476                 pr_err("Unable to allocate channel object\n");
 477                 return;
 478         }
 479
 480         /*
 481          * By default we setup state to enable batched
 482          * reading. A specific service can choose to
 483          * disable this prior to opening the channel.
 484          */
 485         newchannel->batched_reading = true;
 486
 487         /*
 488          * Setup state for signalling the host.
 489          */
 490         newchannel->sig_event = (struct hv_input_signal_event *)
 491                                 (ALIGN((unsigned long)
 492                                 &newchannel->sig_buf,
 493                                 HV_HYPERCALL_PARAM_ALIGN));
 494
 495         newchannel->sig_event->connectionid.asu32 = 0;
 496         newchannel->sig_event->connectionid.u.id = VMBUS_EVENT_CONNECTION_ID;
 497         newchannel->sig_event->flag_number = 0;
 498         newchannel->sig_event->rsvdz = 0;
 499
 500         if (vmbus_proto_version != VERSION_WS2008) {
 501                 newchannel->is_dedicated_interrupt =
 502                                 (offer->is_dedicated_interrupt != 0);
 503                 newchannel->sig_event->connectionid.u.id =
 504                                 offer->connection_id;
 505         }
 506
 507         init_vp_index(newchannel, &offer->offer.if_type);
 508
 509         memcpy(&newchannel->offermsg, offer,
 510                sizeof(struct vmbus_channel_offer_channel));
 511         newchannel->monitor_grp = (u8)offer->monitorid / 32;
 512         newchannel->monitor_bit = (u8)offer->monitorid % 32;
 513
 514         INIT_WORK(&newchannel->work, vmbus_process_offer);
 515         queue_work(newchannel->controlwq, &newchannel->work);
 516 }
 517
 518 /*
 519  * vmbus_onoffer_rescind - Rescind offer handler.
 520  *
 521  * We queue a work item to process this offer synchronously
 522  */
 523 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 524 {
 525         struct vmbus_channel_rescind_offer *rescind;
 526         struct vmbus_channel *channel;
 527         unsigned long flags;
 528
 529         rescind = (struct vmbus_channel_rescind_offer *)hdr;
 530         channel = relid2channel(rescind->child_relid);
 531
 532         if (channel == NULL)
 533                 /* Just return here, no channel found */
 534                 return;
 535
 536         spin_lock_irqsave(&channel->lock, flags);
 537         channel->rescind = true;
 538         /*
 539          * channel->work.func != vmbus_process_rescind_offer means we are still
 540          * processing offer request and the rescind offer processing should be
 541          * postponed. It will be done at the very end of vmbus_process_offer()
 542          * as rescind flag is being checked there.
 543          */
 544         if (channel->work.func == vmbus_process_rescind_offer)
 545                 /* work is initialized for vmbus_process_rescind_offer() from
 546                  * vmbus_process_offer() where the channel got created */
 547                 queue_work(channel->controlwq, &channel->work);
 548
 549         spin_unlock_irqrestore(&channel->lock, flags);
 550 }
 551
 552 /*
 553  * vmbus_onoffers_delivered -
 554  * This is invoked when all offers have been delivered.
 555  *
 556  * Nothing to do here.
 557  */
 558 static void vmbus_onoffers_delivered(
 559                         struct vmbus_channel_message_header *hdr)
 560 {
 561 }
 562
 563 /*
 564  * vmbus_onopen_result - Open result handler.
 565  *
 566  * This is invoked when we received a response to our channel open request.
 567  * Find the matching request, copy the response and signal the requesting
 568  * thread.
 569  */
 570 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
 571 {
 572         struct vmbus_channel_open_result *result;
 573         struct vmbus_channel_msginfo *msginfo;
 574         struct vmbus_channel_message_header *requestheader;
 575         struct vmbus_channel_open_channel *openmsg;
 576         unsigned long flags;
 577
 578         result = (struct vmbus_channel_open_result *)hdr;
 579
 580         /*
 581          * Find the open msg, copy the result and signal/unblock the wait event
 582          */
 583         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 584
 585         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 586                                 msglistentry) {
 587                 requestheader =
 588                         (struct vmbus_channel_message_header *)msginfo->msg;
 589
 590                 if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
 591                         openmsg =
 592                         (struct vmbus_channel_open_channel *)msginfo->msg;
 593                         if (openmsg->child_relid == result->child_relid &&
 594                             openmsg->openid == result->openid) {
 595                                 memcpy(&msginfo->response.open_result,
 596                                        result,
 597                                        sizeof(
 598                                         struct vmbus_channel_open_result));
 599                                 complete(&msginfo->waitevent);
 600                                 break;
 601                         }
 602                 }
 603         }
 604         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 605 }
 606
 607 /*
 608  * vmbus_ongpadl_created - GPADL created handler.
 609  *
 610  * This is invoked when we received a response to our gpadl create request.
 611  * Find the matching request, copy the response and signal the requesting
 612  * thread.
 613  */
 614 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
 615 {
 616         struct vmbus_channel_gpadl_created *gpadlcreated;
 617         struct vmbus_channel_msginfo *msginfo;
 618         struct vmbus_channel_message_header *requestheader;
 619         struct vmbus_channel_gpadl_header *gpadlheader;
 620         unsigned long flags;
 621
 622         gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
 623
 624         /*
 625          * Find the establish msg, copy the result and signal/unblock the wait
 626          * event
 627          */
 628         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 629
 630         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 631                                 msglistentry) {
 632                 requestheader =
 633                         (struct vmbus_channel_message_header *)msginfo->msg;
 634
 635                 if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
 636                         gpadlheader =
 637                         (struct vmbus_channel_gpadl_header *)requestheader;
 638
 639                         if ((gpadlcreated->child_relid ==
 640                              gpadlheader->child_relid) &&
 641                             (gpadlcreated->gpadl == gpadlheader->gpadl)) {
 642                                 memcpy(&msginfo->response.gpadl_created,
 643                                        gpadlcreated,
 644                                        sizeof(
 645                                         struct vmbus_channel_gpadl_created));
 646                                 complete(&msginfo->waitevent);
 647                                 break;
 648                         }
 649                 }
 650         }
 651         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 652 }
 653
 654 /*
 655  * vmbus_ongpadl_torndown - GPADL torndown handler.
 656  *
 657  * This is invoked when we received a response to our gpadl teardown request.
 658  * Find the matching request, copy the response and signal the requesting
 659  * thread.
 660  */
 661 static void vmbus_ongpadl_torndown(
 662                         struct vmbus_channel_message_header *hdr)
 663 {
 664         struct vmbus_channel_gpadl_torndown *gpadl_torndown;
 665         struct vmbus_channel_msginfo *msginfo;
 666         struct vmbus_channel_message_header *requestheader;
 667         struct vmbus_channel_gpadl_teardown *gpadl_teardown;
 668         unsigned long flags;
 669
 670         gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
 671
 672         /*
 673          * Find the open msg, copy the result and signal/unblock the wait event
 674          */
 675         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 676
 677         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 678                                 msglistentry) {
 679                 requestheader =
 680                         (struct vmbus_channel_message_header *)msginfo->msg;
 681
 682                 if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
 683                         gpadl_teardown =
 684                         (struct vmbus_channel_gpadl_teardown *)requestheader;
 685
 686                         if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
 687                                 memcpy(&msginfo->response.gpadl_torndown,
 688                                        gpadl_torndown,
 689                                        sizeof(
 690                                         struct vmbus_channel_gpadl_torndown));
 691                                 complete(&msginfo->waitevent);
 692                                 break;
 693                         }
 694                 }
 695         }
 696         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 697 }
 698
 699 /*
 700  * vmbus_onversion_response - Version response handler
 701  *
 702  * This is invoked when we received a response to our initiate contact request.
 703  * Find the matching request, copy the response and signal the requesting
 704  * thread.
 705  */
 706 static void vmbus_onversion_response(
 707                 struct vmbus_channel_message_header *hdr)
 708 {
 709         struct vmbus_channel_msginfo *msginfo;
 710         struct vmbus_channel_message_header *requestheader;
 711         struct vmbus_channel_version_response *version_response;
 712         unsigned long flags;
 713
 714         version_response = (struct vmbus_channel_version_response *)hdr;
 715         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 716
 717         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 718                                 msglistentry) {
 719                 requestheader =
 720                         (struct vmbus_channel_message_header *)msginfo->msg;
 721
 722                 if (requestheader->msgtype ==
 723                     CHANNELMSG_INITIATE_CONTACT) {
 724                         memcpy(&msginfo->response.version_response,
 725                               version_response,
 726                               sizeof(struct vmbus_channel_version_response));
 727                         complete(&msginfo->waitevent);
 728                 }
 729         }
 730         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 731 }
 732
 733 /* Channel message dispatch table */
 734 static struct vmbus_channel_message_table_entry
 735         channel_message_table[CHANNELMSG_COUNT] = {
 736         {CHANNELMSG_INVALID,                    NULL},
 737         {CHANNELMSG_OFFERCHANNEL,               vmbus_onoffer},
 738         {CHANNELMSG_RESCIND_CHANNELOFFER,       vmbus_onoffer_rescind},
 739         {CHANNELMSG_REQUESTOFFERS,              NULL},
 740         {CHANNELMSG_ALLOFFERS_DELIVERED,        vmbus_onoffers_delivered},
 741         {CHANNELMSG_OPENCHANNEL,                NULL},
 742         {CHANNELMSG_OPENCHANNEL_RESULT, vmbus_onopen_result},
 743         {CHANNELMSG_CLOSECHANNEL,               NULL},
 744         {CHANNELMSG_GPADL_HEADER,               NULL},
 745         {CHANNELMSG_GPADL_BODY,         NULL},
 746         {CHANNELMSG_GPADL_CREATED,              vmbus_ongpadl_created},
 747         {CHANNELMSG_GPADL_TEARDOWN,             NULL},
 748         {CHANNELMSG_GPADL_TORNDOWN,             vmbus_ongpadl_torndown},
 749         {CHANNELMSG_RELID_RELEASED,             NULL},
 750         {CHANNELMSG_INITIATE_CONTACT,           NULL},
 751         {CHANNELMSG_VERSION_RESPONSE,           vmbus_onversion_response},
 752         {CHANNELMSG_UNLOAD,                     NULL},
 753 };
 754
 755 /*
 756  * vmbus_onmessage - Handler for channel protocol messages.
 757  *
 758  * This is invoked in the vmbus worker thread context.
 759  */
 760 void vmbus_onmessage(void *context)
 761 {
 762         struct hv_message *msg = context;
 763         struct vmbus_channel_message_header *hdr;
 764         int size;
 765
 766         hdr = (struct vmbus_channel_message_header *)msg->u.payload;
 767         size = msg->header.payload_size;
 768
 769         if (hdr->msgtype >= CHANNELMSG_COUNT) {
 770                 pr_err("Received invalid channel message type %d size %d\n",
 771                            hdr->msgtype, size);
 772                 print_hex_dump_bytes("", DUMP_PREFIX_NONE,
 773                                      (unsigned char *)msg->u.payload, size);
 774                 return;
 775         }
 776
 777         if (channel_message_table[hdr->msgtype].message_handler)
 778                 channel_message_table[hdr->msgtype].message_handler(hdr);
 779         else
 780                 pr_err("Unhandled channel message type %d\n", hdr->msgtype);
 781 }
 782
 783 /*
 784  * vmbus_request_offers - Send a request to get all our pending offers.
 785  */
 786 int vmbus_request_offers(void)
 787 {
 788         struct vmbus_channel_message_header *msg;
 789         struct vmbus_channel_msginfo *msginfo;
 790         int ret, t;
 791
 792         msginfo = kmalloc(sizeof(*msginfo) +
 793                           sizeof(struct vmbus_channel_message_header),
 794                           GFP_KERNEL);
 795         if (!msginfo)
 796                 return -ENOMEM;
 797
 798         init_completion(&msginfo->waitevent);
 799
 800         msg = (struct vmbus_channel_message_header *)msginfo->msg;
 801
 802         msg->msgtype = CHANNELMSG_REQUESTOFFERS;
 803
 804
 805         ret = vmbus_post_msg(msg,
 806                                sizeof(struct vmbus_channel_message_header));
 807         if (ret != 0) {
 808                 pr_err("Unable to request offers - %d\n", ret);
 809
 810                 goto cleanup;
 811         }
 812
 813         t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
 814         if (t == 0) {
 815                 ret = -ETIMEDOUT;
 816                 goto cleanup;
 817         }
 818
 819
 820
 821 cleanup:
 822         kfree(msginfo);
 823
 824         return ret;
 825 }
 826
 827 /*
 828  * Retrieve the (sub) channel on which to send an outgoing request.
 829  * When a primary channel has multiple sub-channels, we choose a
 830  * channel whose VCPU binding is closest to the VCPU on which
 831  * this call is being made.
 832  */
 833 struct vmbus_channel *vmbus_get_outgoing_channel(struct vmbus_channel *primary)
 834 {
 835         struct list_head *cur, *tmp;
 836         int cur_cpu;
 837         struct vmbus_channel *cur_channel;
 838         struct vmbus_channel *outgoing_channel = primary;
 839         int cpu_distance, new_cpu_distance;
 840
 841         if (list_empty(&primary->sc_list))
 842                 return outgoing_channel;
 843
 844         cur_cpu = hv_context.vp_index[get_cpu()];
 845         put_cpu();
 846         list_for_each_safe(cur, tmp, &primary->sc_list) {
 847                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 848                 if (cur_channel->state != CHANNEL_OPENED_STATE)
 849                         continue;
 850
 851                 if (cur_channel->target_vp == cur_cpu)
 852                         return cur_channel;
 853
 854                 cpu_distance = ((outgoing_channel->target_vp > cur_cpu) ?
 855                                 (outgoing_channel->target_vp - cur_cpu) :
 856                                 (cur_cpu - outgoing_channel->target_vp));
 857
 858                 new_cpu_distance = ((cur_channel->target_vp > cur_cpu) ?
 859                                 (cur_channel->target_vp - cur_cpu) :
 860                                 (cur_cpu - cur_channel->target_vp));
 861
 862                 if (cpu_distance < new_cpu_distance)
 863                         continue;
 864
 865                 outgoing_channel = cur_channel;
 866         }
 867
 868         return outgoing_channel;
 869 }
 870 EXPORT_SYMBOL_GPL(vmbus_get_outgoing_channel);
 871
 872 static void invoke_sc_cb(struct vmbus_channel *primary_channel)
 873 {
 874         struct list_head *cur, *tmp;
 875         struct vmbus_channel *cur_channel;
 876
 877         if (primary_channel->sc_creation_callback == NULL)
 878                 return;
 879
 880         list_for_each_safe(cur, tmp, &primary_channel->sc_list) {
 881                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 882
 883                 primary_channel->sc_creation_callback(cur_channel);
 884         }
 885 }
 886
 887 void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
 888                                 void (*sc_cr_cb)(struct vmbus_channel *new_sc))
 889 {
 890         primary_channel->sc_creation_callback = sc_cr_cb;
 891 }
 892 EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
 893
 894 bool vmbus_are_subchannels_present(struct vmbus_channel *primary)
 895 {
 896         bool ret;
 897
 898         ret = !list_empty(&primary->sc_list);
 899
 900         if (ret) {
 901                 /*
 902                  * Invoke the callback on sub-channel creation.
 903                  * This will present a uniform interface to the
 904                  * clients.
 905                  */
 906                 invoke_sc_cb(primary);
 907         }
 908
 909         return ret;
 910 }
 911 EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present);