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, *tmp;
 216
 217         list_for_each_entry_safe(channel, tmp, &vmbus_connection.chn_list,
 218                 listentry) {
 219                 /* if we don't set rescind to true, vmbus_close_internal()
 220                  * won't invoke hv_process_channel_removal().
 221                  */
 222                 channel->rescind = true;
 223
 224                 vmbus_device_unregister(channel->device_obj);
 225         }
 226 }
 227
 228 /*
 229  * vmbus_process_offer - Process the offer by creating a channel/device
 230  * associated with this offer
 231  */
 232 static void vmbus_process_offer(struct vmbus_channel *newchannel)
 233 {
 234         struct vmbus_channel *channel;
 235         bool fnew = true;
 236         bool enq = false;
 237         unsigned long flags;
 238
 239         /* Make sure this is a new offer */
 240         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 241
 242         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 243                 if (!uuid_le_cmp(channel->offermsg.offer.if_type,
 244                         newchannel->offermsg.offer.if_type) &&
 245                         !uuid_le_cmp(channel->offermsg.offer.if_instance,
 246                                 newchannel->offermsg.offer.if_instance)) {
 247                         fnew = false;
 248                         break;
 249                 }
 250         }
 251
 252         if (fnew) {
 253                 list_add_tail(&newchannel->listentry,
 254                               &vmbus_connection.chn_list);
 255                 enq = true;
 256         }
 257
 258         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 259
 260         if (enq) {
 261                 if (newchannel->target_cpu != get_cpu()) {
 262                         put_cpu();
 263                         smp_call_function_single(newchannel->target_cpu,
 264                                                  percpu_channel_enq,
 265                                                  newchannel, true);
 266                 } else {
 267                         percpu_channel_enq(newchannel);
 268                         put_cpu();
 269                 }
 270         }
 271         if (!fnew) {
 272                 /*
 273                  * Check to see if this is a sub-channel.
 274                  */
 275                 if (newchannel->offermsg.offer.sub_channel_index != 0) {
 276                         /*
 277                          * Process the sub-channel.
 278                          */
 279                         newchannel->primary_channel = channel;
 280                         spin_lock_irqsave(&channel->lock, flags);
 281                         list_add_tail(&newchannel->sc_list, &channel->sc_list);
 282                         spin_unlock_irqrestore(&channel->lock, flags);
 283
 284                         if (newchannel->target_cpu != get_cpu()) {
 285                                 put_cpu();
 286                                 smp_call_function_single(newchannel->target_cpu,
 287                                                          percpu_channel_enq,
 288                                                          newchannel, true);
 289                         } else {
 290                                 percpu_channel_enq(newchannel);
 291                                 put_cpu();
 292                         }
 293
 294                         newchannel->state = CHANNEL_OPEN_STATE;
 295                         channel->num_sc++;
 296                         if (channel->sc_creation_callback != NULL)
 297                                 channel->sc_creation_callback(newchannel);
 298
 299                         return;
 300                 }
 301
 302                 goto err_free_chan;
 303         }
 304
 305         /*
 306          * This state is used to indicate a successful open
 307          * so that when we do close the channel normally, we
 308          * can cleanup properly
 309          */
 310         newchannel->state = CHANNEL_OPEN_STATE;
 311
 312         /*
 313          * Start the process of binding this offer to the driver
 314          * We need to set the DeviceObject field before calling
 315          * vmbus_child_dev_add()
 316          */
 317         newchannel->device_obj = vmbus_device_create(
 318                 &newchannel->offermsg.offer.if_type,
 319                 &newchannel->offermsg.offer.if_instance,
 320                 newchannel);
 321         if (!newchannel->device_obj)
 322                 goto err_deq_chan;
 323
 324         /*
 325          * Add the new device to the bus. This will kick off device-driver
 326          * binding which eventually invokes the device driver's AddDevice()
 327          * method.
 328          */
 329         if (vmbus_device_register(newchannel->device_obj) != 0) {
 330                 pr_err("unable to add child device object (relid %d)\n",
 331                         newchannel->offermsg.child_relid);
 332                 kfree(newchannel->device_obj);
 333                 goto err_deq_chan;
 334         }
 335         return;
 336
 337 err_deq_chan:
 338         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 339         list_del(&newchannel->listentry);
 340         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 341
 342         if (newchannel->target_cpu != get_cpu()) {
 343                 put_cpu();
 344                 smp_call_function_single(newchannel->target_cpu,
 345                                          percpu_channel_deq, newchannel, true);
 346         } else {
 347                 percpu_channel_deq(newchannel);
 348                 put_cpu();
 349         }
 350
 351 err_free_chan:
 352         free_channel(newchannel);
 353 }
 354
 355 enum {
 356         IDE = 0,
 357         SCSI,
 358         NIC,
 359         MAX_PERF_CHN,
 360 };
 361
 362 /*
 363  * This is an array of device_ids (device types) that are performance critical.
 364  * We attempt to distribute the interrupt load for these devices across
 365  * all available CPUs.
 366  */
 367 static const struct hv_vmbus_device_id hp_devs[] = {
 368         /* IDE */
 369         { HV_IDE_GUID, },
 370         /* Storage - SCSI */
 371         { HV_SCSI_GUID, },
 372         /* Network */
 373         { HV_NIC_GUID, },
 374         /* NetworkDirect Guest RDMA */
 375         { HV_ND_GUID, },
 376 };
 377
 378
 379 /*
 380  * We use this state to statically distribute the channel interrupt load.
 381  */
 382 static u32  next_vp;
 383
 384 /*
 385  * Starting with Win8, we can statically distribute the incoming
 386  * channel interrupt load by binding a channel to VCPU. We
 387  * implement here a simple round robin scheme for distributing
 388  * the interrupt load.
 389  * We will bind channels that are not performance critical to cpu 0 and
 390  * performance critical channels (IDE, SCSI and Network) will be uniformly
 391  * distributed across all available CPUs.
 392  */
 393 static void init_vp_index(struct vmbus_channel *channel, const uuid_le *type_guid)
 394 {
 395         u32 cur_cpu;
 396         int i;
 397         bool perf_chn = false;
 398         u32 max_cpus = num_online_cpus();
 399
 400         for (i = IDE; i < MAX_PERF_CHN; i++) {
 401                 if (!memcmp(type_guid->b, hp_devs[i].guid,
 402                                  sizeof(uuid_le))) {
 403                         perf_chn = true;
 404                         break;
 405                 }
 406         }
 407         if ((vmbus_proto_version == VERSION_WS2008) ||
 408             (vmbus_proto_version == VERSION_WIN7) || (!perf_chn)) {
 409                 /*
 410                  * Prior to win8, all channel interrupts are
 411                  * delivered on cpu 0.
 412                  * Also if the channel is not a performance critical
 413                  * channel, bind it to cpu 0.
 414                  */
 415                 channel->target_cpu = 0;
 416                 channel->target_vp = 0;
 417                 return;
 418         }
 419         cur_cpu = (++next_vp % max_cpus);
 420         channel->target_cpu = cur_cpu;
 421         channel->target_vp = hv_context.vp_index[cur_cpu];
 422 }
 423
 424 /*
 425  * vmbus_unload_response - Handler for the unload response.
 426  */
 427 static void vmbus_unload_response(struct vmbus_channel_message_header *hdr)
 428 {
 429         /*
 430          * This is a global event; just wakeup the waiting thread.
 431          * Once we successfully unload, we can cleanup the monitor state.
 432          */
 433         complete(&vmbus_connection.unload_event);
 434 }
 435
 436 void vmbus_initiate_unload(void)
 437 {
 438         struct vmbus_channel_message_header hdr;
 439
 440         init_completion(&vmbus_connection.unload_event);
 441         memset(&hdr, 0, sizeof(struct vmbus_channel_message_header));
 442         hdr.msgtype = CHANNELMSG_UNLOAD;
 443         vmbus_post_msg(&hdr, sizeof(struct vmbus_channel_message_header));
 444
 445         wait_for_completion(&vmbus_connection.unload_event);
 446 }
 447
 448 /*
 449  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 450  *
 451  */
 452 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 453 {
 454         struct vmbus_channel_offer_channel *offer;
 455         struct vmbus_channel *newchannel;
 456
 457         offer = (struct vmbus_channel_offer_channel *)hdr;
 458
 459         /* Allocate the channel object and save this offer. */
 460         newchannel = alloc_channel();
 461         if (!newchannel) {
 462                 pr_err("Unable to allocate channel object\n");
 463                 return;
 464         }
 465
 466         /*
 467          * By default we setup state to enable batched
 468          * reading. A specific service can choose to
 469          * disable this prior to opening the channel.
 470          */
 471         newchannel->batched_reading = true;
 472
 473         /*
 474          * Setup state for signalling the host.
 475          */
 476         newchannel->sig_event = (struct hv_input_signal_event *)
 477                                 (ALIGN((unsigned long)
 478                                 &newchannel->sig_buf,
 479                                 HV_HYPERCALL_PARAM_ALIGN));
 480
 481         newchannel->sig_event->connectionid.asu32 = 0;
 482         newchannel->sig_event->connectionid.u.id = VMBUS_EVENT_CONNECTION_ID;
 483         newchannel->sig_event->flag_number = 0;
 484         newchannel->sig_event->rsvdz = 0;
 485
 486         if (vmbus_proto_version != VERSION_WS2008) {
 487                 newchannel->is_dedicated_interrupt =
 488                                 (offer->is_dedicated_interrupt != 0);
 489                 newchannel->sig_event->connectionid.u.id =
 490                                 offer->connection_id;
 491         }
 492
 493         init_vp_index(newchannel, &offer->offer.if_type);
 494
 495         memcpy(&newchannel->offermsg, offer,
 496                sizeof(struct vmbus_channel_offer_channel));
 497         newchannel->monitor_grp = (u8)offer->monitorid / 32;
 498         newchannel->monitor_bit = (u8)offer->monitorid % 32;
 499
 500         vmbus_process_offer(newchannel);
 501 }
 502
 503 /*
 504  * vmbus_onoffer_rescind - Rescind offer handler.
 505  *
 506  * We queue a work item to process this offer synchronously
 507  */
 508 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 509 {
 510         struct vmbus_channel_rescind_offer *rescind;
 511         struct vmbus_channel *channel;
 512         unsigned long flags;
 513         struct device *dev;
 514
 515         rescind = (struct vmbus_channel_rescind_offer *)hdr;
 516         channel = relid2channel(rescind->child_relid);
 517
 518         if (channel == NULL) {
 519                 hv_process_channel_removal(NULL, rescind->child_relid);
 520                 return;
 521         }
 522
 523         spin_lock_irqsave(&channel->lock, flags);
 524         channel->rescind = true;
 525         spin_unlock_irqrestore(&channel->lock, flags);
 526
 527         if (channel->device_obj) {
 528                 /*
 529                  * We will have to unregister this device from the
 530                  * driver core.
 531                  */
 532                 dev = get_device(&channel->device_obj->device);
 533                 if (dev) {
 534                         vmbus_device_unregister(channel->device_obj);
 535                         put_device(dev);
 536                 }
 537         } else {
 538                 hv_process_channel_removal(channel,
 539                         channel->offermsg.child_relid);
 540         }
 541 }
 542
 543 /*
 544  * vmbus_onoffers_delivered -
 545  * This is invoked when all offers have been delivered.
 546  *
 547  * Nothing to do here.
 548  */
 549 static void vmbus_onoffers_delivered(
 550                         struct vmbus_channel_message_header *hdr)
 551 {
 552 }
 553
 554 /*
 555  * vmbus_onopen_result - Open result handler.
 556  *
 557  * This is invoked when we received a response to our channel open request.
 558  * Find the matching request, copy the response and signal the requesting
 559  * thread.
 560  */
 561 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
 562 {
 563         struct vmbus_channel_open_result *result;
 564         struct vmbus_channel_msginfo *msginfo;
 565         struct vmbus_channel_message_header *requestheader;
 566         struct vmbus_channel_open_channel *openmsg;
 567         unsigned long flags;
 568
 569         result = (struct vmbus_channel_open_result *)hdr;
 570
 571         /*
 572          * Find the open msg, copy the result and signal/unblock the wait event
 573          */
 574         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 575
 576         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 577                                 msglistentry) {
 578                 requestheader =
 579                         (struct vmbus_channel_message_header *)msginfo->msg;
 580
 581                 if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
 582                         openmsg =
 583                         (struct vmbus_channel_open_channel *)msginfo->msg;
 584                         if (openmsg->child_relid == result->child_relid &&
 585                             openmsg->openid == result->openid) {
 586                                 memcpy(&msginfo->response.open_result,
 587                                        result,
 588                                        sizeof(
 589                                         struct vmbus_channel_open_result));
 590                                 complete(&msginfo->waitevent);
 591                                 break;
 592                         }
 593                 }
 594         }
 595         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 596 }
 597
 598 /*
 599  * vmbus_ongpadl_created - GPADL created handler.
 600  *
 601  * This is invoked when we received a response to our gpadl create request.
 602  * Find the matching request, copy the response and signal the requesting
 603  * thread.
 604  */
 605 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
 606 {
 607         struct vmbus_channel_gpadl_created *gpadlcreated;
 608         struct vmbus_channel_msginfo *msginfo;
 609         struct vmbus_channel_message_header *requestheader;
 610         struct vmbus_channel_gpadl_header *gpadlheader;
 611         unsigned long flags;
 612
 613         gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
 614
 615         /*
 616          * Find the establish msg, copy the result and signal/unblock the wait
 617          * event
 618          */
 619         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 620
 621         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 622                                 msglistentry) {
 623                 requestheader =
 624                         (struct vmbus_channel_message_header *)msginfo->msg;
 625
 626                 if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
 627                         gpadlheader =
 628                         (struct vmbus_channel_gpadl_header *)requestheader;
 629
 630                         if ((gpadlcreated->child_relid ==
 631                              gpadlheader->child_relid) &&
 632                             (gpadlcreated->gpadl == gpadlheader->gpadl)) {
 633                                 memcpy(&msginfo->response.gpadl_created,
 634                                        gpadlcreated,
 635                                        sizeof(
 636                                         struct vmbus_channel_gpadl_created));
 637                                 complete(&msginfo->waitevent);
 638                                 break;
 639                         }
 640                 }
 641         }
 642         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 643 }
 644
 645 /*
 646  * vmbus_ongpadl_torndown - GPADL torndown handler.
 647  *
 648  * This is invoked when we received a response to our gpadl teardown request.
 649  * Find the matching request, copy the response and signal the requesting
 650  * thread.
 651  */
 652 static void vmbus_ongpadl_torndown(
 653                         struct vmbus_channel_message_header *hdr)
 654 {
 655         struct vmbus_channel_gpadl_torndown *gpadl_torndown;
 656         struct vmbus_channel_msginfo *msginfo;
 657         struct vmbus_channel_message_header *requestheader;
 658         struct vmbus_channel_gpadl_teardown *gpadl_teardown;
 659         unsigned long flags;
 660
 661         gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
 662
 663         /*
 664          * Find the open msg, copy the result and signal/unblock the wait event
 665          */
 666         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 667
 668         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 669                                 msglistentry) {
 670                 requestheader =
 671                         (struct vmbus_channel_message_header *)msginfo->msg;
 672
 673                 if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
 674                         gpadl_teardown =
 675                         (struct vmbus_channel_gpadl_teardown *)requestheader;
 676
 677                         if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
 678                                 memcpy(&msginfo->response.gpadl_torndown,
 679                                        gpadl_torndown,
 680                                        sizeof(
 681                                         struct vmbus_channel_gpadl_torndown));
 682                                 complete(&msginfo->waitevent);
 683                                 break;
 684                         }
 685                 }
 686         }
 687         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 688 }
 689
 690 /*
 691  * vmbus_onversion_response - Version response handler
 692  *
 693  * This is invoked when we received a response to our initiate contact request.
 694  * Find the matching request, copy the response and signal the requesting
 695  * thread.
 696  */
 697 static void vmbus_onversion_response(
 698                 struct vmbus_channel_message_header *hdr)
 699 {
 700         struct vmbus_channel_msginfo *msginfo;
 701         struct vmbus_channel_message_header *requestheader;
 702         struct vmbus_channel_version_response *version_response;
 703         unsigned long flags;
 704
 705         version_response = (struct vmbus_channel_version_response *)hdr;
 706         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 707
 708         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 709                                 msglistentry) {
 710                 requestheader =
 711                         (struct vmbus_channel_message_header *)msginfo->msg;
 712
 713                 if (requestheader->msgtype ==
 714                     CHANNELMSG_INITIATE_CONTACT) {
 715                         memcpy(&msginfo->response.version_response,
 716                               version_response,
 717                               sizeof(struct vmbus_channel_version_response));
 718                         complete(&msginfo->waitevent);
 719                 }
 720         }
 721         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 722 }
 723
 724 /* Channel message dispatch table */
 725 struct vmbus_channel_message_table_entry
 726         channel_message_table[CHANNELMSG_COUNT] = {
 727         {CHANNELMSG_INVALID,                    0, NULL},
 728         {CHANNELMSG_OFFERCHANNEL,               0, vmbus_onoffer},
 729         {CHANNELMSG_RESCIND_CHANNELOFFER,       0, vmbus_onoffer_rescind},
 730         {CHANNELMSG_REQUESTOFFERS,              0, NULL},
 731         {CHANNELMSG_ALLOFFERS_DELIVERED,        1, vmbus_onoffers_delivered},
 732         {CHANNELMSG_OPENCHANNEL,                0, NULL},
 733         {CHANNELMSG_OPENCHANNEL_RESULT,         1, vmbus_onopen_result},
 734         {CHANNELMSG_CLOSECHANNEL,               0, NULL},
 735         {CHANNELMSG_GPADL_HEADER,               0, NULL},
 736         {CHANNELMSG_GPADL_BODY,                 0, NULL},
 737         {CHANNELMSG_GPADL_CREATED,              1, vmbus_ongpadl_created},
 738         {CHANNELMSG_GPADL_TEARDOWN,             0, NULL},
 739         {CHANNELMSG_GPADL_TORNDOWN,             1, vmbus_ongpadl_torndown},
 740         {CHANNELMSG_RELID_RELEASED,             0, NULL},
 741         {CHANNELMSG_INITIATE_CONTACT,           0, NULL},
 742         {CHANNELMSG_VERSION_RESPONSE,           1, vmbus_onversion_response},
 743         {CHANNELMSG_UNLOAD,                     0, NULL},
 744         {CHANNELMSG_UNLOAD_RESPONSE,            1, vmbus_unload_response},
 745 };
 746
 747 /*
 748  * vmbus_onmessage - Handler for channel protocol messages.
 749  *
 750  * This is invoked in the vmbus worker thread context.
 751  */
 752 void vmbus_onmessage(void *context)
 753 {
 754         struct hv_message *msg = context;
 755         struct vmbus_channel_message_header *hdr;
 756         int size;
 757
 758         hdr = (struct vmbus_channel_message_header *)msg->u.payload;
 759         size = msg->header.payload_size;
 760
 761         if (hdr->msgtype >= CHANNELMSG_COUNT) {
 762                 pr_err("Received invalid channel message type %d size %d\n",
 763                            hdr->msgtype, size);
 764                 print_hex_dump_bytes("", DUMP_PREFIX_NONE,
 765                                      (unsigned char *)msg->u.payload, size);
 766                 return;
 767         }
 768
 769         if (channel_message_table[hdr->msgtype].message_handler)
 770                 channel_message_table[hdr->msgtype].message_handler(hdr);
 771         else
 772                 pr_err("Unhandled channel message type %d\n", hdr->msgtype);
 773 }
 774
 775 /*
 776  * vmbus_request_offers - Send a request to get all our pending offers.
 777  */
 778 int vmbus_request_offers(void)
 779 {
 780         struct vmbus_channel_message_header *msg;
 781         struct vmbus_channel_msginfo *msginfo;
 782         int ret;
 783
 784         msginfo = kmalloc(sizeof(*msginfo) +
 785                           sizeof(struct vmbus_channel_message_header),
 786                           GFP_KERNEL);
 787         if (!msginfo)
 788                 return -ENOMEM;
 789
 790         msg = (struct vmbus_channel_message_header *)msginfo->msg;
 791
 792         msg->msgtype = CHANNELMSG_REQUESTOFFERS;
 793
 794
 795         ret = vmbus_post_msg(msg,
 796                                sizeof(struct vmbus_channel_message_header));
 797         if (ret != 0) {
 798                 pr_err("Unable to request offers - %d\n", ret);
 799
 800                 goto cleanup;
 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 try to
 812  * distribute the load equally amongst all available channels.
 813  */
 814 struct vmbus_channel *vmbus_get_outgoing_channel(struct vmbus_channel *primary)
 815 {
 816         struct list_head *cur, *tmp;
 817         int cur_cpu;
 818         struct vmbus_channel *cur_channel;
 819         struct vmbus_channel *outgoing_channel = primary;
 820         int next_channel;
 821         int i = 1;
 822
 823         if (list_empty(&primary->sc_list))
 824                 return outgoing_channel;
 825
 826         next_channel = primary->next_oc++;
 827
 828         if (next_channel > (primary->num_sc)) {
 829                 primary->next_oc = 0;
 830                 return outgoing_channel;
 831         }
 832
 833         cur_cpu = hv_context.vp_index[get_cpu()];
 834         put_cpu();
 835         list_for_each_safe(cur, tmp, &primary->sc_list) {
 836                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 837                 if (cur_channel->state != CHANNEL_OPENED_STATE)
 838                         continue;
 839
 840                 if (cur_channel->target_vp == cur_cpu)
 841                         return cur_channel;
 842
 843                 if (i == next_channel)
 844                         return cur_channel;
 845
 846                 i++;
 847         }
 848
 849         return outgoing_channel;
 850 }
 851 EXPORT_SYMBOL_GPL(vmbus_get_outgoing_channel);
 852
 853 static void invoke_sc_cb(struct vmbus_channel *primary_channel)
 854 {
 855         struct list_head *cur, *tmp;
 856         struct vmbus_channel *cur_channel;
 857
 858         if (primary_channel->sc_creation_callback == NULL)
 859                 return;
 860
 861         list_for_each_safe(cur, tmp, &primary_channel->sc_list) {
 862                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 863
 864                 primary_channel->sc_creation_callback(cur_channel);
 865         }
 866 }
 867
 868 void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
 869                                 void (*sc_cr_cb)(struct vmbus_channel *new_sc))
 870 {
 871         primary_channel->sc_creation_callback = sc_cr_cb;
 872 }
 873 EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
 874
 875 bool vmbus_are_subchannels_present(struct vmbus_channel *primary)
 876 {
 877         bool ret;
 878
 879         ret = !list_empty(&primary->sc_list);
 880
 881         if (ret) {
 882                 /*
 883                  * Invoke the callback on sub-channel creation.
 884                  * This will present a uniform interface to the
 885                  * clients.
 886                  */
 887                 invoke_sc_cb(primary);
 888         }
 889
 890         return ret;
 891 }
 892 EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present);