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 static void init_vp_index(struct vmbus_channel *channel,
  36                           const uuid_le *type_guid);
  37
  38 /**
  39  * vmbus_prep_negotiate_resp() - Create default response for Hyper-V Negotiate message
  40  * @icmsghdrp: Pointer to msg header structure
  41  * @icmsg_negotiate: Pointer to negotiate message structure
  42  * @buf: Raw buffer channel data
  43  *
  44  * @icmsghdrp is of type &struct icmsg_hdr.
  45  * @negop is of type &struct icmsg_negotiate.
  46  * Set up and fill in default negotiate response message.
  47  *
  48  * The fw_version specifies the  framework version that
  49  * we can support and srv_version specifies the service
  50  * version we can support.
  51  *
  52  * Mainly used by Hyper-V drivers.
  53  */
  54 bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
  55                                 struct icmsg_negotiate *negop, u8 *buf,
  56                                 int fw_version, int srv_version)
  57 {
  58         int icframe_major, icframe_minor;
  59         int icmsg_major, icmsg_minor;
  60         int fw_major, fw_minor;
  61         int srv_major, srv_minor;
  62         int i;
  63         bool found_match = false;
  64
  65         icmsghdrp->icmsgsize = 0x10;
  66         fw_major = (fw_version >> 16);
  67         fw_minor = (fw_version & 0xFFFF);
  68
  69         srv_major = (srv_version >> 16);
  70         srv_minor = (srv_version & 0xFFFF);
  71
  72         negop = (struct icmsg_negotiate *)&buf[
  73                 sizeof(struct vmbuspipe_hdr) +
  74                 sizeof(struct icmsg_hdr)];
  75
  76         icframe_major = negop->icframe_vercnt;
  77         icframe_minor = 0;
  78
  79         icmsg_major = negop->icmsg_vercnt;
  80         icmsg_minor = 0;
  81
  82         /*
  83          * Select the framework version number we will
  84          * support.
  85          */
  86
  87         for (i = 0; i < negop->icframe_vercnt; i++) {
  88                 if ((negop->icversion_data[i].major == fw_major) &&
  89                    (negop->icversion_data[i].minor == fw_minor)) {
  90                         icframe_major = negop->icversion_data[i].major;
  91                         icframe_minor = negop->icversion_data[i].minor;
  92                         found_match = true;
  93                 }
  94         }
  95
  96         if (!found_match)
  97                 goto fw_error;
  98
  99         found_match = false;
 100
 101         for (i = negop->icframe_vercnt;
 102                  (i < negop->icframe_vercnt + negop->icmsg_vercnt); i++) {
 103                 if ((negop->icversion_data[i].major == srv_major) &&
 104                    (negop->icversion_data[i].minor == srv_minor)) {
 105                         icmsg_major = negop->icversion_data[i].major;
 106                         icmsg_minor = negop->icversion_data[i].minor;
 107                         found_match = true;
 108                 }
 109         }
 110
 111         /*
 112          * Respond with the framework and service
 113          * version numbers we can support.
 114          */
 115
 116 fw_error:
 117         if (!found_match) {
 118                 negop->icframe_vercnt = 0;
 119                 negop->icmsg_vercnt = 0;
 120         } else {
 121                 negop->icframe_vercnt = 1;
 122                 negop->icmsg_vercnt = 1;
 123         }
 124
 125         negop->icversion_data[0].major = icframe_major;
 126         negop->icversion_data[0].minor = icframe_minor;
 127         negop->icversion_data[1].major = icmsg_major;
 128         negop->icversion_data[1].minor = icmsg_minor;
 129         return found_match;
 130 }
 131
 132 EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);
 133
 134 /*
 135  * alloc_channel - Allocate and initialize a vmbus channel object
 136  */
 137 static struct vmbus_channel *alloc_channel(void)
 138 {
 139         static atomic_t chan_num = ATOMIC_INIT(0);
 140         struct vmbus_channel *channel;
 141
 142         channel = kzalloc(sizeof(*channel), GFP_ATOMIC);
 143         if (!channel)
 144                 return NULL;
 145
 146         channel->id = atomic_inc_return(&chan_num);
 147         spin_lock_init(&channel->inbound_lock);
 148         spin_lock_init(&channel->lock);
 149
 150         INIT_LIST_HEAD(&channel->sc_list);
 151         INIT_LIST_HEAD(&channel->percpu_list);
 152
 153         return channel;
 154 }
 155
 156 /*
 157  * free_channel - Release the resources used by the vmbus channel object
 158  */
 159 static void free_channel(struct vmbus_channel *channel)
 160 {
 161         kfree(channel);
 162 }
 163
 164 static void percpu_channel_enq(void *arg)
 165 {
 166         struct vmbus_channel *channel = arg;
 167         int cpu = smp_processor_id();
 168
 169         list_add_tail(&channel->percpu_list, &hv_context.percpu_list[cpu]);
 170 }
 171
 172 static void percpu_channel_deq(void *arg)
 173 {
 174         struct vmbus_channel *channel = arg;
 175
 176         list_del(&channel->percpu_list);
 177 }
 178
 179
 180 void hv_process_channel_removal(struct vmbus_channel *channel, u32 relid)
 181 {
 182         struct vmbus_channel_relid_released msg;
 183         unsigned long flags;
 184         struct vmbus_channel *primary_channel;
 185
 186         memset(&msg, 0, sizeof(struct vmbus_channel_relid_released));
 187         msg.child_relid = relid;
 188         msg.header.msgtype = CHANNELMSG_RELID_RELEASED;
 189         vmbus_post_msg(&msg, sizeof(struct vmbus_channel_relid_released));
 190
 191         if (channel == NULL)
 192                 return;
 193
 194         if (channel->target_cpu != get_cpu()) {
 195                 put_cpu();
 196                 smp_call_function_single(channel->target_cpu,
 197                                          percpu_channel_deq, channel, true);
 198         } else {
 199                 percpu_channel_deq(channel);
 200                 put_cpu();
 201         }
 202
 203         if (channel->primary_channel == NULL) {
 204                 spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 205                 list_del(&channel->listentry);
 206                 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 207         } else {
 208                 primary_channel = channel->primary_channel;
 209                 spin_lock_irqsave(&primary_channel->lock, flags);
 210                 list_del(&channel->sc_list);
 211                 primary_channel->num_sc--;
 212                 spin_unlock_irqrestore(&primary_channel->lock, flags);
 213         }
 214         free_channel(channel);
 215 }
 216
 217 void vmbus_free_channels(void)
 218 {
 219         struct vmbus_channel *channel, *tmp;
 220
 221         list_for_each_entry_safe(channel, tmp, &vmbus_connection.chn_list,
 222                 listentry) {
 223                 /* if we don't set rescind to true, vmbus_close_internal()
 224                  * won't invoke hv_process_channel_removal().
 225                  */
 226                 channel->rescind = true;
 227
 228                 vmbus_device_unregister(channel->device_obj);
 229         }
 230 }
 231
 232 /*
 233  * vmbus_process_offer - Process the offer by creating a channel/device
 234  * associated with this offer
 235  */
 236 static void vmbus_process_offer(struct vmbus_channel *newchannel)
 237 {
 238         struct vmbus_channel *channel;
 239         bool fnew = true;
 240         unsigned long flags;
 241
 242         /* Make sure this is a new offer */
 243         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 244
 245         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 246                 if (!uuid_le_cmp(channel->offermsg.offer.if_type,
 247                         newchannel->offermsg.offer.if_type) &&
 248                         !uuid_le_cmp(channel->offermsg.offer.if_instance,
 249                                 newchannel->offermsg.offer.if_instance)) {
 250                         fnew = false;
 251                         break;
 252                 }
 253         }
 254
 255         if (fnew)
 256                 list_add_tail(&newchannel->listentry,
 257                               &vmbus_connection.chn_list);
 258
 259         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 260
 261         if (!fnew) {
 262                 /*
 263                  * Check to see if this is a sub-channel.
 264                  */
 265                 if (newchannel->offermsg.offer.sub_channel_index != 0) {
 266                         /*
 267                          * Process the sub-channel.
 268                          */
 269                         newchannel->primary_channel = channel;
 270                         spin_lock_irqsave(&channel->lock, flags);
 271                         list_add_tail(&newchannel->sc_list, &channel->sc_list);
 272                         channel->num_sc++;
 273                         spin_unlock_irqrestore(&channel->lock, flags);
 274                 } else
 275                         goto err_free_chan;
 276         }
 277
 278         init_vp_index(newchannel, &newchannel->offermsg.offer.if_type);
 279
 280         if (newchannel->target_cpu != get_cpu()) {
 281                 put_cpu();
 282                 smp_call_function_single(newchannel->target_cpu,
 283                                          percpu_channel_enq,
 284                                          newchannel, true);
 285         } else {
 286                 percpu_channel_enq(newchannel);
 287                 put_cpu();
 288         }
 289
 290         /*
 291          * This state is used to indicate a successful open
 292          * so that when we do close the channel normally, we
 293          * can cleanup properly
 294          */
 295         newchannel->state = CHANNEL_OPEN_STATE;
 296
 297         if (!fnew) {
 298                 if (channel->sc_creation_callback != NULL)
 299                         channel->sc_creation_callback(newchannel);
 300                 return;
 301         }
 302
 303         /*
 304          * Start the process of binding this offer to the driver
 305          * We need to set the DeviceObject field before calling
 306          * vmbus_child_dev_add()
 307          */
 308         newchannel->device_obj = vmbus_device_create(
 309                 &newchannel->offermsg.offer.if_type,
 310                 &newchannel->offermsg.offer.if_instance,
 311                 newchannel);
 312         if (!newchannel->device_obj)
 313                 goto err_deq_chan;
 314
 315         /*
 316          * Add the new device to the bus. This will kick off device-driver
 317          * binding which eventually invokes the device driver's AddDevice()
 318          * method.
 319          */
 320         if (vmbus_device_register(newchannel->device_obj) != 0) {
 321                 pr_err("unable to add child device object (relid %d)\n",
 322                         newchannel->offermsg.child_relid);
 323                 kfree(newchannel->device_obj);
 324                 goto err_deq_chan;
 325         }
 326         return;
 327
 328 err_deq_chan:
 329         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 330         list_del(&newchannel->listentry);
 331         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 332
 333         if (newchannel->target_cpu != get_cpu()) {
 334                 put_cpu();
 335                 smp_call_function_single(newchannel->target_cpu,
 336                                          percpu_channel_deq, newchannel, true);
 337         } else {
 338                 percpu_channel_deq(newchannel);
 339                 put_cpu();
 340         }
 341
 342 err_free_chan:
 343         free_channel(newchannel);
 344 }
 345
 346 enum {
 347         IDE = 0,
 348         SCSI,
 349         NIC,
 350         MAX_PERF_CHN,
 351 };
 352
 353 /*
 354  * This is an array of device_ids (device types) that are performance critical.
 355  * We attempt to distribute the interrupt load for these devices across
 356  * all available CPUs.
 357  */
 358 static const struct hv_vmbus_device_id hp_devs[] = {
 359         /* IDE */
 360         { HV_IDE_GUID, },
 361         /* Storage - SCSI */
 362         { HV_SCSI_GUID, },
 363         /* Network */
 364         { HV_NIC_GUID, },
 365         /* NetworkDirect Guest RDMA */
 366         { HV_ND_GUID, },
 367 };
 368
 369
 370 /*
 371  * We use this state to statically distribute the channel interrupt load.
 372  */
 373 static u32  next_vp;
 374
 375 /*
 376  * Starting with Win8, we can statically distribute the incoming
 377  * channel interrupt load by binding a channel to VCPU. We
 378  * implement here a simple round robin scheme for distributing
 379  * the interrupt load.
 380  * We will bind channels that are not performance critical to cpu 0 and
 381  * performance critical channels (IDE, SCSI and Network) will be uniformly
 382  * distributed across all available CPUs.
 383  */
 384 static void init_vp_index(struct vmbus_channel *channel, const uuid_le *type_guid)
 385 {
 386         u32 cur_cpu;
 387         int i;
 388         bool perf_chn = false;
 389         u32 max_cpus = num_online_cpus();
 390
 391         for (i = IDE; i < MAX_PERF_CHN; i++) {
 392                 if (!memcmp(type_guid->b, hp_devs[i].guid,
 393                                  sizeof(uuid_le))) {
 394                         perf_chn = true;
 395                         break;
 396                 }
 397         }
 398         if ((vmbus_proto_version == VERSION_WS2008) ||
 399             (vmbus_proto_version == VERSION_WIN7) || (!perf_chn)) {
 400                 /*
 401                  * Prior to win8, all channel interrupts are
 402                  * delivered on cpu 0.
 403                  * Also if the channel is not a performance critical
 404                  * channel, bind it to cpu 0.
 405                  */
 406                 channel->target_cpu = 0;
 407                 channel->target_vp = 0;
 408                 return;
 409         }
 410         cur_cpu = (++next_vp % max_cpus);
 411         channel->target_cpu = cur_cpu;
 412         channel->target_vp = hv_context.vp_index[cur_cpu];
 413 }
 414
 415 /*
 416  * vmbus_unload_response - Handler for the unload response.
 417  */
 418 static void vmbus_unload_response(struct vmbus_channel_message_header *hdr)
 419 {
 420         /*
 421          * This is a global event; just wakeup the waiting thread.
 422          * Once we successfully unload, we can cleanup the monitor state.
 423          */
 424         complete(&vmbus_connection.unload_event);
 425 }
 426
 427 void vmbus_initiate_unload(void)
 428 {
 429         struct vmbus_channel_message_header hdr;
 430
 431         init_completion(&vmbus_connection.unload_event);
 432         memset(&hdr, 0, sizeof(struct vmbus_channel_message_header));
 433         hdr.msgtype = CHANNELMSG_UNLOAD;
 434         vmbus_post_msg(&hdr, sizeof(struct vmbus_channel_message_header));
 435
 436         wait_for_completion(&vmbus_connection.unload_event);
 437 }
 438
 439 /*
 440  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 441  *
 442  */
 443 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 444 {
 445         struct vmbus_channel_offer_channel *offer;
 446         struct vmbus_channel *newchannel;
 447
 448         offer = (struct vmbus_channel_offer_channel *)hdr;
 449
 450         /* Allocate the channel object and save this offer. */
 451         newchannel = alloc_channel();
 452         if (!newchannel) {
 453                 pr_err("Unable to allocate channel object\n");
 454                 return;
 455         }
 456
 457         /*
 458          * By default we setup state to enable batched
 459          * reading. A specific service can choose to
 460          * disable this prior to opening the channel.
 461          */
 462         newchannel->batched_reading = true;
 463
 464         /*
 465          * Setup state for signalling the host.
 466          */
 467         newchannel->sig_event = (struct hv_input_signal_event *)
 468                                 (ALIGN((unsigned long)
 469                                 &newchannel->sig_buf,
 470                                 HV_HYPERCALL_PARAM_ALIGN));
 471
 472         newchannel->sig_event->connectionid.asu32 = 0;
 473         newchannel->sig_event->connectionid.u.id = VMBUS_EVENT_CONNECTION_ID;
 474         newchannel->sig_event->flag_number = 0;
 475         newchannel->sig_event->rsvdz = 0;
 476
 477         if (vmbus_proto_version != VERSION_WS2008) {
 478                 newchannel->is_dedicated_interrupt =
 479                                 (offer->is_dedicated_interrupt != 0);
 480                 newchannel->sig_event->connectionid.u.id =
 481                                 offer->connection_id;
 482         }
 483
 484         memcpy(&newchannel->offermsg, offer,
 485                sizeof(struct vmbus_channel_offer_channel));
 486         newchannel->monitor_grp = (u8)offer->monitorid / 32;
 487         newchannel->monitor_bit = (u8)offer->monitorid % 32;
 488
 489         vmbus_process_offer(newchannel);
 490 }
 491
 492 /*
 493  * vmbus_onoffer_rescind - Rescind offer handler.
 494  *
 495  * We queue a work item to process this offer synchronously
 496  */
 497 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 498 {
 499         struct vmbus_channel_rescind_offer *rescind;
 500         struct vmbus_channel *channel;
 501         unsigned long flags;
 502         struct device *dev;
 503
 504         rescind = (struct vmbus_channel_rescind_offer *)hdr;
 505         channel = relid2channel(rescind->child_relid);
 506
 507         if (channel == NULL) {
 508                 hv_process_channel_removal(NULL, rescind->child_relid);
 509                 return;
 510         }
 511
 512         spin_lock_irqsave(&channel->lock, flags);
 513         channel->rescind = true;
 514         spin_unlock_irqrestore(&channel->lock, flags);
 515
 516         if (channel->device_obj) {
 517                 /*
 518                  * We will have to unregister this device from the
 519                  * driver core.
 520                  */
 521                 dev = get_device(&channel->device_obj->device);
 522                 if (dev) {
 523                         vmbus_device_unregister(channel->device_obj);
 524                         put_device(dev);
 525                 }
 526         } else {
 527                 hv_process_channel_removal(channel,
 528                         channel->offermsg.child_relid);
 529         }
 530 }
 531
 532 /*
 533  * vmbus_onoffers_delivered -
 534  * This is invoked when all offers have been delivered.
 535  *
 536  * Nothing to do here.
 537  */
 538 static void vmbus_onoffers_delivered(
 539                         struct vmbus_channel_message_header *hdr)
 540 {
 541 }
 542
 543 /*
 544  * vmbus_onopen_result - Open result handler.
 545  *
 546  * This is invoked when we received a response to our channel open request.
 547  * Find the matching request, copy the response and signal the requesting
 548  * thread.
 549  */
 550 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
 551 {
 552         struct vmbus_channel_open_result *result;
 553         struct vmbus_channel_msginfo *msginfo;
 554         struct vmbus_channel_message_header *requestheader;
 555         struct vmbus_channel_open_channel *openmsg;
 556         unsigned long flags;
 557
 558         result = (struct vmbus_channel_open_result *)hdr;
 559
 560         /*
 561          * Find the open msg, copy the result and signal/unblock the wait event
 562          */
 563         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 564
 565         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 566                                 msglistentry) {
 567                 requestheader =
 568                         (struct vmbus_channel_message_header *)msginfo->msg;
 569
 570                 if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
 571                         openmsg =
 572                         (struct vmbus_channel_open_channel *)msginfo->msg;
 573                         if (openmsg->child_relid == result->child_relid &&
 574                             openmsg->openid == result->openid) {
 575                                 memcpy(&msginfo->response.open_result,
 576                                        result,
 577                                        sizeof(
 578                                         struct vmbus_channel_open_result));
 579                                 complete(&msginfo->waitevent);
 580                                 break;
 581                         }
 582                 }
 583         }
 584         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 585 }
 586
 587 /*
 588  * vmbus_ongpadl_created - GPADL created handler.
 589  *
 590  * This is invoked when we received a response to our gpadl create request.
 591  * Find the matching request, copy the response and signal the requesting
 592  * thread.
 593  */
 594 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
 595 {
 596         struct vmbus_channel_gpadl_created *gpadlcreated;
 597         struct vmbus_channel_msginfo *msginfo;
 598         struct vmbus_channel_message_header *requestheader;
 599         struct vmbus_channel_gpadl_header *gpadlheader;
 600         unsigned long flags;
 601
 602         gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
 603
 604         /*
 605          * Find the establish msg, copy the result and signal/unblock the wait
 606          * event
 607          */
 608         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 609
 610         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 611                                 msglistentry) {
 612                 requestheader =
 613                         (struct vmbus_channel_message_header *)msginfo->msg;
 614
 615                 if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
 616                         gpadlheader =
 617                         (struct vmbus_channel_gpadl_header *)requestheader;
 618
 619                         if ((gpadlcreated->child_relid ==
 620                              gpadlheader->child_relid) &&
 621                             (gpadlcreated->gpadl == gpadlheader->gpadl)) {
 622                                 memcpy(&msginfo->response.gpadl_created,
 623                                        gpadlcreated,
 624                                        sizeof(
 625                                         struct vmbus_channel_gpadl_created));
 626                                 complete(&msginfo->waitevent);
 627                                 break;
 628                         }
 629                 }
 630         }
 631         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 632 }
 633
 634 /*
 635  * vmbus_ongpadl_torndown - GPADL torndown handler.
 636  *
 637  * This is invoked when we received a response to our gpadl teardown request.
 638  * Find the matching request, copy the response and signal the requesting
 639  * thread.
 640  */
 641 static void vmbus_ongpadl_torndown(
 642                         struct vmbus_channel_message_header *hdr)
 643 {
 644         struct vmbus_channel_gpadl_torndown *gpadl_torndown;
 645         struct vmbus_channel_msginfo *msginfo;
 646         struct vmbus_channel_message_header *requestheader;
 647         struct vmbus_channel_gpadl_teardown *gpadl_teardown;
 648         unsigned long flags;
 649
 650         gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
 651
 652         /*
 653          * Find the open msg, copy the result and signal/unblock the wait event
 654          */
 655         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 656
 657         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 658                                 msglistentry) {
 659                 requestheader =
 660                         (struct vmbus_channel_message_header *)msginfo->msg;
 661
 662                 if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
 663                         gpadl_teardown =
 664                         (struct vmbus_channel_gpadl_teardown *)requestheader;
 665
 666                         if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
 667                                 memcpy(&msginfo->response.gpadl_torndown,
 668                                        gpadl_torndown,
 669                                        sizeof(
 670                                         struct vmbus_channel_gpadl_torndown));
 671                                 complete(&msginfo->waitevent);
 672                                 break;
 673                         }
 674                 }
 675         }
 676         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 677 }
 678
 679 /*
 680  * vmbus_onversion_response - Version response handler
 681  *
 682  * This is invoked when we received a response to our initiate contact request.
 683  * Find the matching request, copy the response and signal the requesting
 684  * thread.
 685  */
 686 static void vmbus_onversion_response(
 687                 struct vmbus_channel_message_header *hdr)
 688 {
 689         struct vmbus_channel_msginfo *msginfo;
 690         struct vmbus_channel_message_header *requestheader;
 691         struct vmbus_channel_version_response *version_response;
 692         unsigned long flags;
 693
 694         version_response = (struct vmbus_channel_version_response *)hdr;
 695         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 696
 697         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 698                                 msglistentry) {
 699                 requestheader =
 700                         (struct vmbus_channel_message_header *)msginfo->msg;
 701
 702                 if (requestheader->msgtype ==
 703                     CHANNELMSG_INITIATE_CONTACT) {
 704                         memcpy(&msginfo->response.version_response,
 705                               version_response,
 706                               sizeof(struct vmbus_channel_version_response));
 707                         complete(&msginfo->waitevent);
 708                 }
 709         }
 710         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 711 }
 712
 713 /* Channel message dispatch table */
 714 struct vmbus_channel_message_table_entry
 715         channel_message_table[CHANNELMSG_COUNT] = {
 716         {CHANNELMSG_INVALID,                    0, NULL},
 717         {CHANNELMSG_OFFERCHANNEL,               0, vmbus_onoffer},
 718         {CHANNELMSG_RESCIND_CHANNELOFFER,       0, vmbus_onoffer_rescind},
 719         {CHANNELMSG_REQUESTOFFERS,              0, NULL},
 720         {CHANNELMSG_ALLOFFERS_DELIVERED,        1, vmbus_onoffers_delivered},
 721         {CHANNELMSG_OPENCHANNEL,                0, NULL},
 722         {CHANNELMSG_OPENCHANNEL_RESULT,         1, vmbus_onopen_result},
 723         {CHANNELMSG_CLOSECHANNEL,               0, NULL},
 724         {CHANNELMSG_GPADL_HEADER,               0, NULL},
 725         {CHANNELMSG_GPADL_BODY,                 0, NULL},
 726         {CHANNELMSG_GPADL_CREATED,              1, vmbus_ongpadl_created},
 727         {CHANNELMSG_GPADL_TEARDOWN,             0, NULL},
 728         {CHANNELMSG_GPADL_TORNDOWN,             1, vmbus_ongpadl_torndown},
 729         {CHANNELMSG_RELID_RELEASED,             0, NULL},
 730         {CHANNELMSG_INITIATE_CONTACT,           0, NULL},
 731         {CHANNELMSG_VERSION_RESPONSE,           1, vmbus_onversion_response},
 732         {CHANNELMSG_UNLOAD,                     0, NULL},
 733         {CHANNELMSG_UNLOAD_RESPONSE,            1, vmbus_unload_response},
 734 };
 735
 736 /*
 737  * vmbus_onmessage - Handler for channel protocol messages.
 738  *
 739  * This is invoked in the vmbus worker thread context.
 740  */
 741 void vmbus_onmessage(void *context)
 742 {
 743         struct hv_message *msg = context;
 744         struct vmbus_channel_message_header *hdr;
 745         int size;
 746
 747         hdr = (struct vmbus_channel_message_header *)msg->u.payload;
 748         size = msg->header.payload_size;
 749
 750         if (hdr->msgtype >= CHANNELMSG_COUNT) {
 751                 pr_err("Received invalid channel message type %d size %d\n",
 752                            hdr->msgtype, size);
 753                 print_hex_dump_bytes("", DUMP_PREFIX_NONE,
 754                                      (unsigned char *)msg->u.payload, size);
 755                 return;
 756         }
 757
 758         if (channel_message_table[hdr->msgtype].message_handler)
 759                 channel_message_table[hdr->msgtype].message_handler(hdr);
 760         else
 761                 pr_err("Unhandled channel message type %d\n", hdr->msgtype);
 762 }
 763
 764 /*
 765  * vmbus_request_offers - Send a request to get all our pending offers.
 766  */
 767 int vmbus_request_offers(void)
 768 {
 769         struct vmbus_channel_message_header *msg;
 770         struct vmbus_channel_msginfo *msginfo;
 771         int ret;
 772
 773         msginfo = kmalloc(sizeof(*msginfo) +
 774                           sizeof(struct vmbus_channel_message_header),
 775                           GFP_KERNEL);
 776         if (!msginfo)
 777                 return -ENOMEM;
 778
 779         msg = (struct vmbus_channel_message_header *)msginfo->msg;
 780
 781         msg->msgtype = CHANNELMSG_REQUESTOFFERS;
 782
 783
 784         ret = vmbus_post_msg(msg,
 785                                sizeof(struct vmbus_channel_message_header));
 786         if (ret != 0) {
 787                 pr_err("Unable to request offers - %d\n", ret);
 788
 789                 goto cleanup;
 790         }
 791
 792 cleanup:
 793         kfree(msginfo);
 794
 795         return ret;
 796 }
 797
 798 /*
 799  * Retrieve the (sub) channel on which to send an outgoing request.
 800  * When a primary channel has multiple sub-channels, we try to
 801  * distribute the load equally amongst all available channels.
 802  */
 803 struct vmbus_channel *vmbus_get_outgoing_channel(struct vmbus_channel *primary)
 804 {
 805         struct list_head *cur, *tmp;
 806         int cur_cpu;
 807         struct vmbus_channel *cur_channel;
 808         struct vmbus_channel *outgoing_channel = primary;
 809         int next_channel;
 810         int i = 1;
 811
 812         if (list_empty(&primary->sc_list))
 813                 return outgoing_channel;
 814
 815         next_channel = primary->next_oc++;
 816
 817         if (next_channel > (primary->num_sc)) {
 818                 primary->next_oc = 0;
 819                 return outgoing_channel;
 820         }
 821
 822         cur_cpu = hv_context.vp_index[get_cpu()];
 823         put_cpu();
 824         list_for_each_safe(cur, tmp, &primary->sc_list) {
 825                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 826                 if (cur_channel->state != CHANNEL_OPENED_STATE)
 827                         continue;
 828
 829                 if (cur_channel->target_vp == cur_cpu)
 830                         return cur_channel;
 831
 832                 if (i == next_channel)
 833                         return cur_channel;
 834
 835                 i++;
 836         }
 837
 838         return outgoing_channel;
 839 }
 840 EXPORT_SYMBOL_GPL(vmbus_get_outgoing_channel);
 841
 842 static void invoke_sc_cb(struct vmbus_channel *primary_channel)
 843 {
 844         struct list_head *cur, *tmp;
 845         struct vmbus_channel *cur_channel;
 846
 847         if (primary_channel->sc_creation_callback == NULL)
 848                 return;
 849
 850         list_for_each_safe(cur, tmp, &primary_channel->sc_list) {
 851                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 852
 853                 primary_channel->sc_creation_callback(cur_channel);
 854         }
 855 }
 856
 857 void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
 858                                 void (*sc_cr_cb)(struct vmbus_channel *new_sc))
 859 {
 860         primary_channel->sc_creation_callback = sc_cr_cb;
 861 }
 862 EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
 863
 864 bool vmbus_are_subchannels_present(struct vmbus_channel *primary)
 865 {
 866         bool ret;
 867
 868         ret = !list_empty(&primary->sc_list);
 869
 870         if (ret) {
 871                 /*
 872                  * Invoke the callback on sub-channel creation.
 873                  * This will present a uniform interface to the
 874                  * clients.
 875                  */
 876                 invoke_sc_cb(primary);
 877         }
 878
 879         return ret;
 880 }
 881 EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present);