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 /**
  36  * vmbus_prep_negotiate_resp() - Create default response for Hyper-V Negotiate message
  37  * @icmsghdrp: Pointer to msg header structure
  38  * @icmsg_negotiate: Pointer to negotiate message structure
  39  * @buf: Raw buffer channel data
  40  *
  41  * @icmsghdrp is of type &struct icmsg_hdr.
  42  * @negop is of type &struct icmsg_negotiate.
  43  * Set up and fill in default negotiate response message.
  44  *
  45  * The fw_version specifies the  framework version that
  46  * we can support and srv_version specifies the service
  47  * version we can support.
  48  *
  49  * Mainly used by Hyper-V drivers.
  50  */
  51 bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
  52                                 struct icmsg_negotiate *negop, u8 *buf,
  53                                 int fw_version, int srv_version)
  54 {
  55         int icframe_major, icframe_minor;
  56         int icmsg_major, icmsg_minor;
  57         int fw_major, fw_minor;
  58         int srv_major, srv_minor;
  59         int i;
  60         bool found_match = false;
  61
  62         icmsghdrp->icmsgsize = 0x10;
  63         fw_major = (fw_version >> 16);
  64         fw_minor = (fw_version & 0xFFFF);
  65
  66         srv_major = (srv_version >> 16);
  67         srv_minor = (srv_version & 0xFFFF);
  68
  69         negop = (struct icmsg_negotiate *)&buf[
  70                 sizeof(struct vmbuspipe_hdr) +
  71                 sizeof(struct icmsg_hdr)];
  72
  73         icframe_major = negop->icframe_vercnt;
  74         icframe_minor = 0;
  75
  76         icmsg_major = negop->icmsg_vercnt;
  77         icmsg_minor = 0;
  78
  79         /*
  80          * Select the framework version number we will
  81          * support.
  82          */
  83
  84         for (i = 0; i < negop->icframe_vercnt; i++) {
  85                 if ((negop->icversion_data[i].major == fw_major) &&
  86                    (negop->icversion_data[i].minor == fw_minor)) {
  87                         icframe_major = negop->icversion_data[i].major;
  88                         icframe_minor = negop->icversion_data[i].minor;
  89                         found_match = true;
  90                 }
  91         }
  92
  93         if (!found_match)
  94                 goto fw_error;
  95
  96         found_match = false;
  97
  98         for (i = negop->icframe_vercnt;
  99                  (i < negop->icframe_vercnt + negop->icmsg_vercnt); i++) {
 100                 if ((negop->icversion_data[i].major == srv_major) &&
 101                    (negop->icversion_data[i].minor == srv_minor)) {
 102                         icmsg_major = negop->icversion_data[i].major;
 103                         icmsg_minor = negop->icversion_data[i].minor;
 104                         found_match = true;
 105                 }
 106         }
 107
 108         /*
 109          * Respond with the framework and service
 110          * version numbers we can support.
 111          */
 112
 113 fw_error:
 114         if (!found_match) {
 115                 negop->icframe_vercnt = 0;
 116                 negop->icmsg_vercnt = 0;
 117         } else {
 118                 negop->icframe_vercnt = 1;
 119                 negop->icmsg_vercnt = 1;
 120         }
 121
 122         negop->icversion_data[0].major = icframe_major;
 123         negop->icversion_data[0].minor = icframe_minor;
 124         negop->icversion_data[1].major = icmsg_major;
 125         negop->icversion_data[1].minor = icmsg_minor;
 126         return found_match;
 127 }
 128
 129 EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);
 130
 131 /*
 132  * alloc_channel - Allocate and initialize a vmbus channel object
 133  */
 134 static struct vmbus_channel *alloc_channel(void)
 135 {
 136         static atomic_t chan_num = ATOMIC_INIT(0);
 137         struct vmbus_channel *channel;
 138
 139         channel = kzalloc(sizeof(*channel), GFP_ATOMIC);
 140         if (!channel)
 141                 return NULL;
 142
 143         channel->id = atomic_inc_return(&chan_num);
 144         spin_lock_init(&channel->inbound_lock);
 145         spin_lock_init(&channel->lock);
 146
 147         INIT_LIST_HEAD(&channel->sc_list);
 148         INIT_LIST_HEAD(&channel->percpu_list);
 149
 150         return channel;
 151 }
 152
 153 /*
 154  * free_channel - Release the resources used by the vmbus channel object
 155  */
 156 static void free_channel(struct vmbus_channel *channel)
 157 {
 158         kfree(channel);
 159 }
 160
 161 static void percpu_channel_enq(void *arg)
 162 {
 163         struct vmbus_channel *channel = arg;
 164         int cpu = smp_processor_id();
 165
 166         list_add_tail(&channel->percpu_list, &hv_context.percpu_list[cpu]);
 167 }
 168
 169 static void percpu_channel_deq(void *arg)
 170 {
 171         struct vmbus_channel *channel = arg;
 172
 173         list_del(&channel->percpu_list);
 174 }
 175
 176
 177 void hv_process_channel_removal(struct vmbus_channel *channel, u32 relid)
 178 {
 179         struct vmbus_channel_relid_released msg;
 180         unsigned long flags;
 181         struct vmbus_channel *primary_channel;
 182
 183         memset(&msg, 0, sizeof(struct vmbus_channel_relid_released));
 184         msg.child_relid = relid;
 185         msg.header.msgtype = CHANNELMSG_RELID_RELEASED;
 186         vmbus_post_msg(&msg, sizeof(struct vmbus_channel_relid_released));
 187
 188         if (channel == NULL)
 189                 return;
 190
 191         if (channel->target_cpu != get_cpu()) {
 192                 put_cpu();
 193                 smp_call_function_single(channel->target_cpu,
 194                                          percpu_channel_deq, channel, true);
 195         } else {
 196                 percpu_channel_deq(channel);
 197                 put_cpu();
 198         }
 199
 200         if (channel->primary_channel == NULL) {
 201                 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 202                 list_del(&channel->listentry);
 203                 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 204         } else {
 205                 primary_channel = channel->primary_channel;
 206                 spin_lock_irqsave(&primary_channel->lock, flags);
 207                 list_del(&channel->sc_list);
 208                 spin_unlock_irqrestore(&primary_channel->lock, flags);
 209         }
 210         free_channel(channel);
 211 }
 212
 213 void vmbus_free_channels(void)
 214 {
 215         struct vmbus_channel *channel;
 216
 217         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 218                 vmbus_device_unregister(channel->device_obj);
 219                 free_channel(channel);
 220         }
 221 }
 222
 223 /*
 224  * vmbus_process_offer - Process the offer by creating a channel/device
 225  * associated with this offer
 226  */
 227 static void vmbus_process_offer(struct vmbus_channel *newchannel)
 228 {
 229         struct vmbus_channel *channel;
 230         bool fnew = true;
 231         bool enq = false;
 232         unsigned long flags;
 233
 234         /* Make sure this is a new offer */
 235         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 236
 237         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 238                 if (!uuid_le_cmp(channel->offermsg.offer.if_type,
 239                         newchannel->offermsg.offer.if_type) &&
 240                         !uuid_le_cmp(channel->offermsg.offer.if_instance,
 241                                 newchannel->offermsg.offer.if_instance)) {
 242                         fnew = false;
 243                         break;
 244                 }
 245         }
 246
 247         if (fnew) {
 248                 list_add_tail(&newchannel->listentry,
 249                               &vmbus_connection.chn_list);
 250                 enq = true;
 251         }
 252
 253         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 254
 255         if (enq) {
 256                 if (newchannel->target_cpu != get_cpu()) {
 257                         put_cpu();
 258                         smp_call_function_single(newchannel->target_cpu,
 259                                                  percpu_channel_enq,
 260                                                  newchannel, true);
 261                 } else {
 262                         percpu_channel_enq(newchannel);
 263                         put_cpu();
 264                 }
 265         }
 266         if (!fnew) {
 267                 /*
 268                  * Check to see if this is a sub-channel.
 269                  */
 270                 if (newchannel->offermsg.offer.sub_channel_index != 0) {
 271                         /*
 272                          * Process the sub-channel.
 273                          */
 274                         newchannel->primary_channel = channel;
 275                         spin_lock_irqsave(&channel->lock, flags);
 276                         list_add_tail(&newchannel->sc_list, &channel->sc_list);
 277                         spin_unlock_irqrestore(&channel->lock, flags);
 278
 279                         if (newchannel->target_cpu != get_cpu()) {
 280                                 put_cpu();
 281                                 smp_call_function_single(newchannel->target_cpu,
 282                                                          percpu_channel_enq,
 283                                                          newchannel, true);
 284                         } else {
 285                                 percpu_channel_enq(newchannel);
 286                                 put_cpu();
 287                         }
 288
 289                         newchannel->state = CHANNEL_OPEN_STATE;
 290                         channel->num_sc++;
 291                         if (channel->sc_creation_callback != NULL)
 292                                 channel->sc_creation_callback(newchannel);
 293
 294                         return;
 295                 }
 296
 297                 goto err_free_chan;
 298         }
 299
 300         /*
 301          * This state is used to indicate a successful open
 302          * so that when we do close the channel normally, we
 303          * can cleanup properly
 304          */
 305         newchannel->state = CHANNEL_OPEN_STATE;
 306
 307         /*
 308          * Start the process of binding this offer to the driver
 309          * We need to set the DeviceObject field before calling
 310          * vmbus_child_dev_add()
 311          */
 312         newchannel->device_obj = vmbus_device_create(
 313                 &newchannel->offermsg.offer.if_type,
 314                 &newchannel->offermsg.offer.if_instance,
 315                 newchannel);
 316         if (!newchannel->device_obj)
 317                 goto err_deq_chan;
 318
 319         /*
 320          * Add the new device to the bus. This will kick off device-driver
 321          * binding which eventually invokes the device driver's AddDevice()
 322          * method.
 323          */
 324         if (vmbus_device_register(newchannel->device_obj) != 0) {
 325                 pr_err("unable to add child device object (relid %d)\n",
 326                         newchannel->offermsg.child_relid);
 327                 kfree(newchannel->device_obj);
 328                 goto err_deq_chan;
 329         }
 330         return;
 331
 332 err_deq_chan:
 333         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 334         list_del(&newchannel->listentry);
 335         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 336
 337         if (newchannel->target_cpu != get_cpu()) {
 338                 put_cpu();
 339                 smp_call_function_single(newchannel->target_cpu,
 340                                          percpu_channel_deq, newchannel, true);
 341         } else {
 342                 percpu_channel_deq(newchannel);
 343                 put_cpu();
 344         }
 345
 346 err_free_chan:
 347         free_channel(newchannel);
 348 }
 349
 350 enum {
 351         IDE = 0,
 352         SCSI,
 353         NIC,
 354         MAX_PERF_CHN,
 355 };
 356
 357 /*
 358  * This is an array of device_ids (device types) that are performance critical.
 359  * We attempt to distribute the interrupt load for these devices across
 360  * all available CPUs.
 361  */
 362 static const struct hv_vmbus_device_id hp_devs[] = {
 363         /* IDE */
 364         { HV_IDE_GUID, },
 365         /* Storage - SCSI */
 366         { HV_SCSI_GUID, },
 367         /* Network */
 368         { HV_NIC_GUID, },
 369         /* NetworkDirect Guest RDMA */
 370         { HV_ND_GUID, },
 371 };
 372
 373
 374 /*
 375  * We use this state to statically distribute the channel interrupt load.
 376  */
 377 static u32  next_vp;
 378
 379 /*
 380  * Starting with Win8, we can statically distribute the incoming
 381  * channel interrupt load by binding a channel to VCPU. We
 382  * implement here a simple round robin scheme for distributing
 383  * the interrupt load.
 384  * We will bind channels that are not performance critical to cpu 0 and
 385  * performance critical channels (IDE, SCSI and Network) will be uniformly
 386  * distributed across all available CPUs.
 387  */
 388 static void init_vp_index(struct vmbus_channel *channel, const uuid_le *type_guid)
 389 {
 390         u32 cur_cpu;
 391         int i;
 392         bool perf_chn = false;
 393         u32 max_cpus = num_online_cpus();
 394
 395         for (i = IDE; i < MAX_PERF_CHN; i++) {
 396                 if (!memcmp(type_guid->b, hp_devs[i].guid,
 397                                  sizeof(uuid_le))) {
 398                         perf_chn = true;
 399                         break;
 400                 }
 401         }
 402         if ((vmbus_proto_version == VERSION_WS2008) ||
 403             (vmbus_proto_version == VERSION_WIN7) || (!perf_chn)) {
 404                 /*
 405                  * Prior to win8, all channel interrupts are
 406                  * delivered on cpu 0.
 407                  * Also if the channel is not a performance critical
 408                  * channel, bind it to cpu 0.
 409                  */
 410                 channel->target_cpu = 0;
 411                 channel->target_vp = 0;
 412                 return;
 413         }
 414         cur_cpu = (++next_vp % max_cpus);
 415         channel->target_cpu = cur_cpu;
 416         channel->target_vp = hv_context.vp_index[cur_cpu];
 417 }
 418
 419 /*
 420  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 421  *
 422  */
 423 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 424 {
 425         struct vmbus_channel_offer_channel *offer;
 426         struct vmbus_channel *newchannel;
 427
 428         offer = (struct vmbus_channel_offer_channel *)hdr;
 429
 430         /* Allocate the channel object and save this offer. */
 431         newchannel = alloc_channel();
 432         if (!newchannel) {
 433                 pr_err("Unable to allocate channel object\n");
 434                 return;
 435         }
 436
 437         /*
 438          * By default we setup state to enable batched
 439          * reading. A specific service can choose to
 440          * disable this prior to opening the channel.
 441          */
 442         newchannel->batched_reading = true;
 443
 444         /*
 445          * Setup state for signalling the host.
 446          */
 447         newchannel->sig_event = (struct hv_input_signal_event *)
 448                                 (ALIGN((unsigned long)
 449                                 &newchannel->sig_buf,
 450                                 HV_HYPERCALL_PARAM_ALIGN));
 451
 452         newchannel->sig_event->connectionid.asu32 = 0;
 453         newchannel->sig_event->connectionid.u.id = VMBUS_EVENT_CONNECTION_ID;
 454         newchannel->sig_event->flag_number = 0;
 455         newchannel->sig_event->rsvdz = 0;
 456
 457         if (vmbus_proto_version != VERSION_WS2008) {
 458                 newchannel->is_dedicated_interrupt =
 459                                 (offer->is_dedicated_interrupt != 0);
 460                 newchannel->sig_event->connectionid.u.id =
 461                                 offer->connection_id;
 462         }
 463
 464         init_vp_index(newchannel, &offer->offer.if_type);
 465
 466         memcpy(&newchannel->offermsg, offer,
 467                sizeof(struct vmbus_channel_offer_channel));
 468         newchannel->monitor_grp = (u8)offer->monitorid / 32;
 469         newchannel->monitor_bit = (u8)offer->monitorid % 32;
 470
 471         vmbus_process_offer(newchannel);
 472 }
 473
 474 /*
 475  * vmbus_onoffer_rescind - Rescind offer handler.
 476  *
 477  * We queue a work item to process this offer synchronously
 478  */
 479 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 480 {
 481         struct vmbus_channel_rescind_offer *rescind;
 482         struct vmbus_channel *channel;
 483         unsigned long flags;
 484         struct device *dev;
 485
 486         rescind = (struct vmbus_channel_rescind_offer *)hdr;
 487         channel = relid2channel(rescind->child_relid);
 488
 489         if (channel == NULL) {
 490                 hv_process_channel_removal(NULL, rescind->child_relid);
 491                 return;
 492         }
 493
 494         spin_lock_irqsave(&channel->lock, flags);
 495         channel->rescind = true;
 496         spin_unlock_irqrestore(&channel->lock, flags);
 497
 498         if (channel->device_obj) {
 499                 /*
 500                  * We will have to unregister this device from the
 501                  * driver core.
 502                  */
 503                 dev = get_device(&channel->device_obj->device);
 504                 if (dev) {
 505                         vmbus_device_unregister(channel->device_obj);
 506                         put_device(dev);
 507                 }
 508         } else {
 509                 hv_process_channel_removal(channel,
 510                         channel->offermsg.child_relid);
 511         }
 512 }
 513
 514 /*
 515  * vmbus_onoffers_delivered -
 516  * This is invoked when all offers have been delivered.
 517  *
 518  * Nothing to do here.
 519  */
 520 static void vmbus_onoffers_delivered(
 521                         struct vmbus_channel_message_header *hdr)
 522 {
 523 }
 524
 525 /*
 526  * vmbus_onopen_result - Open result handler.
 527  *
 528  * This is invoked when we received a response to our channel open request.
 529  * Find the matching request, copy the response and signal the requesting
 530  * thread.
 531  */
 532 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
 533 {
 534         struct vmbus_channel_open_result *result;
 535         struct vmbus_channel_msginfo *msginfo;
 536         struct vmbus_channel_message_header *requestheader;
 537         struct vmbus_channel_open_channel *openmsg;
 538         unsigned long flags;
 539
 540         result = (struct vmbus_channel_open_result *)hdr;
 541
 542         /*
 543          * Find the open msg, copy the result and signal/unblock the wait event
 544          */
 545         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 546
 547         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 548                                 msglistentry) {
 549                 requestheader =
 550                         (struct vmbus_channel_message_header *)msginfo->msg;
 551
 552                 if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
 553                         openmsg =
 554                         (struct vmbus_channel_open_channel *)msginfo->msg;
 555                         if (openmsg->child_relid == result->child_relid &&
 556                             openmsg->openid == result->openid) {
 557                                 memcpy(&msginfo->response.open_result,
 558                                        result,
 559                                        sizeof(
 560                                         struct vmbus_channel_open_result));
 561                                 complete(&msginfo->waitevent);
 562                                 break;
 563                         }
 564                 }
 565         }
 566         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 567 }
 568
 569 /*
 570  * vmbus_ongpadl_created - GPADL created handler.
 571  *
 572  * This is invoked when we received a response to our gpadl create request.
 573  * Find the matching request, copy the response and signal the requesting
 574  * thread.
 575  */
 576 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
 577 {
 578         struct vmbus_channel_gpadl_created *gpadlcreated;
 579         struct vmbus_channel_msginfo *msginfo;
 580         struct vmbus_channel_message_header *requestheader;
 581         struct vmbus_channel_gpadl_header *gpadlheader;
 582         unsigned long flags;
 583
 584         gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
 585
 586         /*
 587          * Find the establish msg, copy the result and signal/unblock the wait
 588          * event
 589          */
 590         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 591
 592         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 593                                 msglistentry) {
 594                 requestheader =
 595                         (struct vmbus_channel_message_header *)msginfo->msg;
 596
 597                 if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
 598                         gpadlheader =
 599                         (struct vmbus_channel_gpadl_header *)requestheader;
 600
 601                         if ((gpadlcreated->child_relid ==
 602                              gpadlheader->child_relid) &&
 603                             (gpadlcreated->gpadl == gpadlheader->gpadl)) {
 604                                 memcpy(&msginfo->response.gpadl_created,
 605                                        gpadlcreated,
 606                                        sizeof(
 607                                         struct vmbus_channel_gpadl_created));
 608                                 complete(&msginfo->waitevent);
 609                                 break;
 610                         }
 611                 }
 612         }
 613         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 614 }
 615
 616 /*
 617  * vmbus_ongpadl_torndown - GPADL torndown handler.
 618  *
 619  * This is invoked when we received a response to our gpadl teardown request.
 620  * Find the matching request, copy the response and signal the requesting
 621  * thread.
 622  */
 623 static void vmbus_ongpadl_torndown(
 624                         struct vmbus_channel_message_header *hdr)
 625 {
 626         struct vmbus_channel_gpadl_torndown *gpadl_torndown;
 627         struct vmbus_channel_msginfo *msginfo;
 628         struct vmbus_channel_message_header *requestheader;
 629         struct vmbus_channel_gpadl_teardown *gpadl_teardown;
 630         unsigned long flags;
 631
 632         gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
 633
 634         /*
 635          * Find the open msg, copy the result and signal/unblock the wait event
 636          */
 637         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 638
 639         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 640                                 msglistentry) {
 641                 requestheader =
 642                         (struct vmbus_channel_message_header *)msginfo->msg;
 643
 644                 if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
 645                         gpadl_teardown =
 646                         (struct vmbus_channel_gpadl_teardown *)requestheader;
 647
 648                         if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
 649                                 memcpy(&msginfo->response.gpadl_torndown,
 650                                        gpadl_torndown,
 651                                        sizeof(
 652                                         struct vmbus_channel_gpadl_torndown));
 653                                 complete(&msginfo->waitevent);
 654                                 break;
 655                         }
 656                 }
 657         }
 658         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 659 }
 660
 661 /*
 662  * vmbus_onversion_response - Version response handler
 663  *
 664  * This is invoked when we received a response to our initiate contact request.
 665  * Find the matching request, copy the response and signal the requesting
 666  * thread.
 667  */
 668 static void vmbus_onversion_response(
 669                 struct vmbus_channel_message_header *hdr)
 670 {
 671         struct vmbus_channel_msginfo *msginfo;
 672         struct vmbus_channel_message_header *requestheader;
 673         struct vmbus_channel_version_response *version_response;
 674         unsigned long flags;
 675
 676         version_response = (struct vmbus_channel_version_response *)hdr;
 677         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 678
 679         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 680                                 msglistentry) {
 681                 requestheader =
 682                         (struct vmbus_channel_message_header *)msginfo->msg;
 683
 684                 if (requestheader->msgtype ==
 685                     CHANNELMSG_INITIATE_CONTACT) {
 686                         memcpy(&msginfo->response.version_response,
 687                               version_response,
 688                               sizeof(struct vmbus_channel_version_response));
 689                         complete(&msginfo->waitevent);
 690                 }
 691         }
 692         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 693 }
 694
 695 /* Channel message dispatch table */
 696 struct vmbus_channel_message_table_entry
 697         channel_message_table[CHANNELMSG_COUNT] = {
 698         {CHANNELMSG_INVALID,                    0, NULL},
 699         {CHANNELMSG_OFFERCHANNEL,               0, vmbus_onoffer},
 700         {CHANNELMSG_RESCIND_CHANNELOFFER,       0, vmbus_onoffer_rescind},
 701         {CHANNELMSG_REQUESTOFFERS,              0, NULL},
 702         {CHANNELMSG_ALLOFFERS_DELIVERED,        1, vmbus_onoffers_delivered},
 703         {CHANNELMSG_OPENCHANNEL,                0, NULL},
 704         {CHANNELMSG_OPENCHANNEL_RESULT,         1, vmbus_onopen_result},
 705         {CHANNELMSG_CLOSECHANNEL,               0, NULL},
 706         {CHANNELMSG_GPADL_HEADER,               0, NULL},
 707         {CHANNELMSG_GPADL_BODY,                 0, NULL},
 708         {CHANNELMSG_GPADL_CREATED,              1, vmbus_ongpadl_created},
 709         {CHANNELMSG_GPADL_TEARDOWN,             0, NULL},
 710         {CHANNELMSG_GPADL_TORNDOWN,             1, vmbus_ongpadl_torndown},
 711         {CHANNELMSG_RELID_RELEASED,             0, NULL},
 712         {CHANNELMSG_INITIATE_CONTACT,           0, NULL},
 713         {CHANNELMSG_VERSION_RESPONSE,           1, vmbus_onversion_response},
 714         {CHANNELMSG_UNLOAD,                     0, NULL},
 715 };
 716
 717 /*
 718  * vmbus_onmessage - Handler for channel protocol messages.
 719  *
 720  * This is invoked in the vmbus worker thread context.
 721  */
 722 void vmbus_onmessage(void *context)
 723 {
 724         struct hv_message *msg = context;
 725         struct vmbus_channel_message_header *hdr;
 726         int size;
 727
 728         hdr = (struct vmbus_channel_message_header *)msg->u.payload;
 729         size = msg->header.payload_size;
 730
 731         if (hdr->msgtype >= CHANNELMSG_COUNT) {
 732                 pr_err("Received invalid channel message type %d size %d\n",
 733                            hdr->msgtype, size);
 734                 print_hex_dump_bytes("", DUMP_PREFIX_NONE,
 735                                      (unsigned char *)msg->u.payload, size);
 736                 return;
 737         }
 738
 739         if (channel_message_table[hdr->msgtype].message_handler)
 740                 channel_message_table[hdr->msgtype].message_handler(hdr);
 741         else
 742                 pr_err("Unhandled channel message type %d\n", hdr->msgtype);
 743 }
 744
 745 /*
 746  * vmbus_request_offers - Send a request to get all our pending offers.
 747  */
 748 int vmbus_request_offers(void)
 749 {
 750         struct vmbus_channel_message_header *msg;
 751         struct vmbus_channel_msginfo *msginfo;
 752         int ret;
 753
 754         msginfo = kmalloc(sizeof(*msginfo) +
 755                           sizeof(struct vmbus_channel_message_header),
 756                           GFP_KERNEL);
 757         if (!msginfo)
 758                 return -ENOMEM;
 759
 760         msg = (struct vmbus_channel_message_header *)msginfo->msg;
 761
 762         msg->msgtype = CHANNELMSG_REQUESTOFFERS;
 763
 764
 765         ret = vmbus_post_msg(msg,
 766                                sizeof(struct vmbus_channel_message_header));
 767         if (ret != 0) {
 768                 pr_err("Unable to request offers - %d\n", ret);
 769
 770                 goto cleanup;
 771         }
 772
 773 cleanup:
 774         kfree(msginfo);
 775
 776         return ret;
 777 }
 778
 779 /*
 780  * Retrieve the (sub) channel on which to send an outgoing request.
 781  * When a primary channel has multiple sub-channels, we try to
 782  * distribute the load equally amongst all available channels.
 783  */
 784 struct vmbus_channel *vmbus_get_outgoing_channel(struct vmbus_channel *primary)
 785 {
 786         struct list_head *cur, *tmp;
 787         int cur_cpu;
 788         struct vmbus_channel *cur_channel;
 789         struct vmbus_channel *outgoing_channel = primary;
 790         int next_channel;
 791         int i = 1;
 792
 793         if (list_empty(&primary->sc_list))
 794                 return outgoing_channel;
 795
 796         next_channel = primary->next_oc++;
 797
 798         if (next_channel > (primary->num_sc)) {
 799                 primary->next_oc = 0;
 800                 return outgoing_channel;
 801         }
 802
 803         cur_cpu = hv_context.vp_index[get_cpu()];
 804         put_cpu();
 805         list_for_each_safe(cur, tmp, &primary->sc_list) {
 806                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 807                 if (cur_channel->state != CHANNEL_OPENED_STATE)
 808                         continue;
 809
 810                 if (cur_channel->target_vp == cur_cpu)
 811                         return cur_channel;
 812
 813                 if (i == next_channel)
 814                         return cur_channel;
 815
 816                 i++;
 817         }
 818
 819         return outgoing_channel;
 820 }
 821 EXPORT_SYMBOL_GPL(vmbus_get_outgoing_channel);
 822
 823 static void invoke_sc_cb(struct vmbus_channel *primary_channel)
 824 {
 825         struct list_head *cur, *tmp;
 826         struct vmbus_channel *cur_channel;
 827
 828         if (primary_channel->sc_creation_callback == NULL)
 829                 return;
 830
 831         list_for_each_safe(cur, tmp, &primary_channel->sc_list) {
 832                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 833
 834                 primary_channel->sc_creation_callback(cur_channel);
 835         }
 836 }
 837
 838 void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
 839                                 void (*sc_cr_cb)(struct vmbus_channel *new_sc))
 840 {
 841         primary_channel->sc_creation_callback = sc_cr_cb;
 842 }
 843 EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
 844
 845 bool vmbus_are_subchannels_present(struct vmbus_channel *primary)
 846 {
 847         bool ret;
 848
 849         ret = !list_empty(&primary->sc_list);
 850
 851         if (ret) {
 852                 /*
 853                  * Invoke the callback on sub-channel creation.
 854                  * This will present a uniform interface to the
 855                  * clients.
 856                  */
 857                 invoke_sc_cb(primary);
 858         }
 859
 860         return ret;
 861 }
 862 EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present);