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         ND_NIC,
 351         MAX_PERF_CHN,
 352 };
 353
 354 /*
 355  * This is an array of device_ids (device types) that are performance critical.
 356  * We attempt to distribute the interrupt load for these devices across
 357  * all available CPUs.
 358  */
 359 static const struct hv_vmbus_device_id hp_devs[] = {
 360         /* IDE */
 361         { HV_IDE_GUID, },
 362         /* Storage - SCSI */
 363         { HV_SCSI_GUID, },
 364         /* Network */
 365         { HV_NIC_GUID, },
 366         /* NetworkDirect Guest RDMA */
 367         { HV_ND_GUID, },
 368 };
 369
 370
 371 /*
 372  * We use this state to statically distribute the channel interrupt load.
 373  */
 374 static int next_numa_node_id;
 375
 376 /*
 377  * Starting with Win8, we can statically distribute the incoming
 378  * channel interrupt load by binding a channel to VCPU.
 379  * We do this in a hierarchical fashion:
 380  * First distribute the primary channels across available NUMA nodes
 381  * and then distribute the subchannels amongst the CPUs in the NUMA
 382  * node assigned to the primary channel.
 383  *
 384  * For pre-win8 hosts or non-performance critical channels we assign the
 385  * first CPU in the first NUMA node.
 386  */
 387 static void init_vp_index(struct vmbus_channel *channel, const uuid_le *type_guid)
 388 {
 389         u32 cur_cpu;
 390         int i;
 391         bool perf_chn = false;
 392         struct vmbus_channel *primary = channel->primary_channel;
 393         int next_node;
 394         struct cpumask available_mask;
 395         struct cpumask *alloced_mask;
 396
 397         for (i = IDE; i < MAX_PERF_CHN; i++) {
 398                 if (!memcmp(type_guid->b, hp_devs[i].guid,
 399                                  sizeof(uuid_le))) {
 400                         perf_chn = true;
 401                         break;
 402                 }
 403         }
 404         if ((vmbus_proto_version == VERSION_WS2008) ||
 405             (vmbus_proto_version == VERSION_WIN7) || (!perf_chn)) {
 406                 /*
 407                  * Prior to win8, all channel interrupts are
 408                  * delivered on cpu 0.
 409                  * Also if the channel is not a performance critical
 410                  * channel, bind it to cpu 0.
 411                  */
 412                 channel->numa_node = 0;
 413                 channel->target_cpu = 0;
 414                 channel->target_vp = hv_context.vp_index[0];
 415                 return;
 416         }
 417
 418         /*
 419          * We distribute primary channels evenly across all the available
 420          * NUMA nodes and within the assigned NUMA node we will assign the
 421          * first available CPU to the primary channel.
 422          * The sub-channels will be assigned to the CPUs available in the
 423          * NUMA node evenly.
 424          */
 425         if (!primary) {
 426                 while (true) {
 427                         next_node = next_numa_node_id++;
 428                         if (next_node == nr_node_ids)
 429                                 next_node = next_numa_node_id = 0;
 430                         if (cpumask_empty(cpumask_of_node(next_node)))
 431                                 continue;
 432                         break;
 433                 }
 434                 channel->numa_node = next_node;
 435                 primary = channel;
 436         }
 437         alloced_mask = &hv_context.hv_numa_map[primary->numa_node];
 438
 439         if (cpumask_weight(alloced_mask) ==
 440             cpumask_weight(cpumask_of_node(primary->numa_node))) {
 441                 /*
 442                  * We have cycled through all the CPUs in the node;
 443                  * reset the alloced map.
 444                  */
 445                 cpumask_clear(alloced_mask);
 446         }
 447
 448         cpumask_xor(&available_mask, alloced_mask,
 449                     cpumask_of_node(primary->numa_node));
 450
 451         cur_cpu = -1;
 452         while (true) {
 453                 cur_cpu = cpumask_next(cur_cpu, &available_mask);
 454                 if (cur_cpu >= nr_cpu_ids) {
 455                         cur_cpu = -1;
 456                         cpumask_copy(&available_mask,
 457                                      cpumask_of_node(primary->numa_node));
 458                         continue;
 459                 }
 460
 461                 if (!cpumask_test_cpu(cur_cpu,
 462                                 &primary->alloced_cpus_in_node)) {
 463                         cpumask_set_cpu(cur_cpu,
 464                                         &primary->alloced_cpus_in_node);
 465                         cpumask_set_cpu(cur_cpu, alloced_mask);
 466                         break;
 467                 }
 468         }
 469
 470         channel->target_cpu = cur_cpu;
 471         channel->target_vp = hv_context.vp_index[cur_cpu];
 472 }
 473
 474 /*
 475  * vmbus_unload_response - Handler for the unload response.
 476  */
 477 static void vmbus_unload_response(struct vmbus_channel_message_header *hdr)
 478 {
 479         /*
 480          * This is a global event; just wakeup the waiting thread.
 481          * Once we successfully unload, we can cleanup the monitor state.
 482          */
 483         complete(&vmbus_connection.unload_event);
 484 }
 485
 486 void vmbus_initiate_unload(void)
 487 {
 488         struct vmbus_channel_message_header hdr;
 489
 490         /* Pre-Win2012R2 hosts don't support reconnect */
 491         if (vmbus_proto_version < VERSION_WIN8_1)
 492                 return;
 493
 494         init_completion(&vmbus_connection.unload_event);
 495         memset(&hdr, 0, sizeof(struct vmbus_channel_message_header));
 496         hdr.msgtype = CHANNELMSG_UNLOAD;
 497         vmbus_post_msg(&hdr, sizeof(struct vmbus_channel_message_header));
 498
 499         wait_for_completion(&vmbus_connection.unload_event);
 500 }
 501
 502 /*
 503  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 504  *
 505  */
 506 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 507 {
 508         struct vmbus_channel_offer_channel *offer;
 509         struct vmbus_channel *newchannel;
 510
 511         offer = (struct vmbus_channel_offer_channel *)hdr;
 512
 513         /* Allocate the channel object and save this offer. */
 514         newchannel = alloc_channel();
 515         if (!newchannel) {
 516                 pr_err("Unable to allocate channel object\n");
 517                 return;
 518         }
 519
 520         /*
 521          * By default we setup state to enable batched
 522          * reading. A specific service can choose to
 523          * disable this prior to opening the channel.
 524          */
 525         newchannel->batched_reading = true;
 526
 527         /*
 528          * Setup state for signalling the host.
 529          */
 530         newchannel->sig_event = (struct hv_input_signal_event *)
 531                                 (ALIGN((unsigned long)
 532                                 &newchannel->sig_buf,
 533                                 HV_HYPERCALL_PARAM_ALIGN));
 534
 535         newchannel->sig_event->connectionid.asu32 = 0;
 536         newchannel->sig_event->connectionid.u.id = VMBUS_EVENT_CONNECTION_ID;
 537         newchannel->sig_event->flag_number = 0;
 538         newchannel->sig_event->rsvdz = 0;
 539
 540         if (vmbus_proto_version != VERSION_WS2008) {
 541                 newchannel->is_dedicated_interrupt =
 542                                 (offer->is_dedicated_interrupt != 0);
 543                 newchannel->sig_event->connectionid.u.id =
 544                                 offer->connection_id;
 545         }
 546
 547         memcpy(&newchannel->offermsg, offer,
 548                sizeof(struct vmbus_channel_offer_channel));
 549         newchannel->monitor_grp = (u8)offer->monitorid / 32;
 550         newchannel->monitor_bit = (u8)offer->monitorid % 32;
 551
 552         vmbus_process_offer(newchannel);
 553 }
 554
 555 /*
 556  * vmbus_onoffer_rescind - Rescind offer handler.
 557  *
 558  * We queue a work item to process this offer synchronously
 559  */
 560 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 561 {
 562         struct vmbus_channel_rescind_offer *rescind;
 563         struct vmbus_channel *channel;
 564         unsigned long flags;
 565         struct device *dev;
 566
 567         rescind = (struct vmbus_channel_rescind_offer *)hdr;
 568         channel = relid2channel(rescind->child_relid);
 569
 570         if (channel == NULL) {
 571                 hv_process_channel_removal(NULL, rescind->child_relid);
 572                 return;
 573         }
 574
 575         spin_lock_irqsave(&channel->lock, flags);
 576         channel->rescind = true;
 577         spin_unlock_irqrestore(&channel->lock, flags);
 578
 579         if (channel->device_obj) {
 580                 /*
 581                  * We will have to unregister this device from the
 582                  * driver core.
 583                  */
 584                 dev = get_device(&channel->device_obj->device);
 585                 if (dev) {
 586                         vmbus_device_unregister(channel->device_obj);
 587                         put_device(dev);
 588                 }
 589         } else {
 590                 hv_process_channel_removal(channel,
 591                         channel->offermsg.child_relid);
 592         }
 593 }
 594
 595 /*
 596  * vmbus_onoffers_delivered -
 597  * This is invoked when all offers have been delivered.
 598  *
 599  * Nothing to do here.
 600  */
 601 static void vmbus_onoffers_delivered(
 602                         struct vmbus_channel_message_header *hdr)
 603 {
 604 }
 605
 606 /*
 607  * vmbus_onopen_result - Open result handler.
 608  *
 609  * This is invoked when we received a response to our channel open request.
 610  * Find the matching request, copy the response and signal the requesting
 611  * thread.
 612  */
 613 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
 614 {
 615         struct vmbus_channel_open_result *result;
 616         struct vmbus_channel_msginfo *msginfo;
 617         struct vmbus_channel_message_header *requestheader;
 618         struct vmbus_channel_open_channel *openmsg;
 619         unsigned long flags;
 620
 621         result = (struct vmbus_channel_open_result *)hdr;
 622
 623         /*
 624          * Find the open msg, copy the result and signal/unblock the wait event
 625          */
 626         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 627
 628         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 629                                 msglistentry) {
 630                 requestheader =
 631                         (struct vmbus_channel_message_header *)msginfo->msg;
 632
 633                 if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
 634                         openmsg =
 635                         (struct vmbus_channel_open_channel *)msginfo->msg;
 636                         if (openmsg->child_relid == result->child_relid &&
 637                             openmsg->openid == result->openid) {
 638                                 memcpy(&msginfo->response.open_result,
 639                                        result,
 640                                        sizeof(
 641                                         struct vmbus_channel_open_result));
 642                                 complete(&msginfo->waitevent);
 643                                 break;
 644                         }
 645                 }
 646         }
 647         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 648 }
 649
 650 /*
 651  * vmbus_ongpadl_created - GPADL created handler.
 652  *
 653  * This is invoked when we received a response to our gpadl create request.
 654  * Find the matching request, copy the response and signal the requesting
 655  * thread.
 656  */
 657 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
 658 {
 659         struct vmbus_channel_gpadl_created *gpadlcreated;
 660         struct vmbus_channel_msginfo *msginfo;
 661         struct vmbus_channel_message_header *requestheader;
 662         struct vmbus_channel_gpadl_header *gpadlheader;
 663         unsigned long flags;
 664
 665         gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
 666
 667         /*
 668          * Find the establish msg, copy the result and signal/unblock the wait
 669          * event
 670          */
 671         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 672
 673         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 674                                 msglistentry) {
 675                 requestheader =
 676                         (struct vmbus_channel_message_header *)msginfo->msg;
 677
 678                 if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
 679                         gpadlheader =
 680                         (struct vmbus_channel_gpadl_header *)requestheader;
 681
 682                         if ((gpadlcreated->child_relid ==
 683                              gpadlheader->child_relid) &&
 684                             (gpadlcreated->gpadl == gpadlheader->gpadl)) {
 685                                 memcpy(&msginfo->response.gpadl_created,
 686                                        gpadlcreated,
 687                                        sizeof(
 688                                         struct vmbus_channel_gpadl_created));
 689                                 complete(&msginfo->waitevent);
 690                                 break;
 691                         }
 692                 }
 693         }
 694         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 695 }
 696
 697 /*
 698  * vmbus_ongpadl_torndown - GPADL torndown handler.
 699  *
 700  * This is invoked when we received a response to our gpadl teardown request.
 701  * Find the matching request, copy the response and signal the requesting
 702  * thread.
 703  */
 704 static void vmbus_ongpadl_torndown(
 705                         struct vmbus_channel_message_header *hdr)
 706 {
 707         struct vmbus_channel_gpadl_torndown *gpadl_torndown;
 708         struct vmbus_channel_msginfo *msginfo;
 709         struct vmbus_channel_message_header *requestheader;
 710         struct vmbus_channel_gpadl_teardown *gpadl_teardown;
 711         unsigned long flags;
 712
 713         gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
 714
 715         /*
 716          * Find the open msg, copy the result and signal/unblock the wait event
 717          */
 718         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 719
 720         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 721                                 msglistentry) {
 722                 requestheader =
 723                         (struct vmbus_channel_message_header *)msginfo->msg;
 724
 725                 if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
 726                         gpadl_teardown =
 727                         (struct vmbus_channel_gpadl_teardown *)requestheader;
 728
 729                         if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
 730                                 memcpy(&msginfo->response.gpadl_torndown,
 731                                        gpadl_torndown,
 732                                        sizeof(
 733                                         struct vmbus_channel_gpadl_torndown));
 734                                 complete(&msginfo->waitevent);
 735                                 break;
 736                         }
 737                 }
 738         }
 739         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 740 }
 741
 742 /*
 743  * vmbus_onversion_response - Version response handler
 744  *
 745  * This is invoked when we received a response to our initiate contact request.
 746  * Find the matching request, copy the response and signal the requesting
 747  * thread.
 748  */
 749 static void vmbus_onversion_response(
 750                 struct vmbus_channel_message_header *hdr)
 751 {
 752         struct vmbus_channel_msginfo *msginfo;
 753         struct vmbus_channel_message_header *requestheader;
 754         struct vmbus_channel_version_response *version_response;
 755         unsigned long flags;
 756
 757         version_response = (struct vmbus_channel_version_response *)hdr;
 758         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 759
 760         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 761                                 msglistentry) {
 762                 requestheader =
 763                         (struct vmbus_channel_message_header *)msginfo->msg;
 764
 765                 if (requestheader->msgtype ==
 766                     CHANNELMSG_INITIATE_CONTACT) {
 767                         memcpy(&msginfo->response.version_response,
 768                               version_response,
 769                               sizeof(struct vmbus_channel_version_response));
 770                         complete(&msginfo->waitevent);
 771                 }
 772         }
 773         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 774 }
 775
 776 /* Channel message dispatch table */
 777 struct vmbus_channel_message_table_entry
 778         channel_message_table[CHANNELMSG_COUNT] = {
 779         {CHANNELMSG_INVALID,                    0, NULL},
 780         {CHANNELMSG_OFFERCHANNEL,               0, vmbus_onoffer},
 781         {CHANNELMSG_RESCIND_CHANNELOFFER,       0, vmbus_onoffer_rescind},
 782         {CHANNELMSG_REQUESTOFFERS,              0, NULL},
 783         {CHANNELMSG_ALLOFFERS_DELIVERED,        1, vmbus_onoffers_delivered},
 784         {CHANNELMSG_OPENCHANNEL,                0, NULL},
 785         {CHANNELMSG_OPENCHANNEL_RESULT,         1, vmbus_onopen_result},
 786         {CHANNELMSG_CLOSECHANNEL,               0, NULL},
 787         {CHANNELMSG_GPADL_HEADER,               0, NULL},
 788         {CHANNELMSG_GPADL_BODY,                 0, NULL},
 789         {CHANNELMSG_GPADL_CREATED,              1, vmbus_ongpadl_created},
 790         {CHANNELMSG_GPADL_TEARDOWN,             0, NULL},
 791         {CHANNELMSG_GPADL_TORNDOWN,             1, vmbus_ongpadl_torndown},
 792         {CHANNELMSG_RELID_RELEASED,             0, NULL},
 793         {CHANNELMSG_INITIATE_CONTACT,           0, NULL},
 794         {CHANNELMSG_VERSION_RESPONSE,           1, vmbus_onversion_response},
 795         {CHANNELMSG_UNLOAD,                     0, NULL},
 796         {CHANNELMSG_UNLOAD_RESPONSE,            1, vmbus_unload_response},
 797 };
 798
 799 /*
 800  * vmbus_onmessage - Handler for channel protocol messages.
 801  *
 802  * This is invoked in the vmbus worker thread context.
 803  */
 804 void vmbus_onmessage(void *context)
 805 {
 806         struct hv_message *msg = context;
 807         struct vmbus_channel_message_header *hdr;
 808         int size;
 809
 810         hdr = (struct vmbus_channel_message_header *)msg->u.payload;
 811         size = msg->header.payload_size;
 812
 813         if (hdr->msgtype >= CHANNELMSG_COUNT) {
 814                 pr_err("Received invalid channel message type %d size %d\n",
 815                            hdr->msgtype, size);
 816                 print_hex_dump_bytes("", DUMP_PREFIX_NONE,
 817                                      (unsigned char *)msg->u.payload, size);
 818                 return;
 819         }
 820
 821         if (channel_message_table[hdr->msgtype].message_handler)
 822                 channel_message_table[hdr->msgtype].message_handler(hdr);
 823         else
 824                 pr_err("Unhandled channel message type %d\n", hdr->msgtype);
 825 }
 826
 827 /*
 828  * vmbus_request_offers - Send a request to get all our pending offers.
 829  */
 830 int vmbus_request_offers(void)
 831 {
 832         struct vmbus_channel_message_header *msg;
 833         struct vmbus_channel_msginfo *msginfo;
 834         int ret;
 835
 836         msginfo = kmalloc(sizeof(*msginfo) +
 837                           sizeof(struct vmbus_channel_message_header),
 838                           GFP_KERNEL);
 839         if (!msginfo)
 840                 return -ENOMEM;
 841
 842         msg = (struct vmbus_channel_message_header *)msginfo->msg;
 843
 844         msg->msgtype = CHANNELMSG_REQUESTOFFERS;
 845
 846
 847         ret = vmbus_post_msg(msg,
 848                                sizeof(struct vmbus_channel_message_header));
 849         if (ret != 0) {
 850                 pr_err("Unable to request offers - %d\n", ret);
 851
 852                 goto cleanup;
 853         }
 854
 855 cleanup:
 856         kfree(msginfo);
 857
 858         return ret;
 859 }
 860
 861 /*
 862  * Retrieve the (sub) channel on which to send an outgoing request.
 863  * When a primary channel has multiple sub-channels, we try to
 864  * distribute the load equally amongst all available channels.
 865  */
 866 struct vmbus_channel *vmbus_get_outgoing_channel(struct vmbus_channel *primary)
 867 {
 868         struct list_head *cur, *tmp;
 869         int cur_cpu;
 870         struct vmbus_channel *cur_channel;
 871         struct vmbus_channel *outgoing_channel = primary;
 872         int next_channel;
 873         int i = 1;
 874
 875         if (list_empty(&primary->sc_list))
 876                 return outgoing_channel;
 877
 878         next_channel = primary->next_oc++;
 879
 880         if (next_channel > (primary->num_sc)) {
 881                 primary->next_oc = 0;
 882                 return outgoing_channel;
 883         }
 884
 885         cur_cpu = hv_context.vp_index[get_cpu()];
 886         put_cpu();
 887         list_for_each_safe(cur, tmp, &primary->sc_list) {
 888                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 889                 if (cur_channel->state != CHANNEL_OPENED_STATE)
 890                         continue;
 891
 892                 if (cur_channel->target_vp == cur_cpu)
 893                         return cur_channel;
 894
 895                 if (i == next_channel)
 896                         return cur_channel;
 897
 898                 i++;
 899         }
 900
 901         return outgoing_channel;
 902 }
 903 EXPORT_SYMBOL_GPL(vmbus_get_outgoing_channel);
 904
 905 static void invoke_sc_cb(struct vmbus_channel *primary_channel)
 906 {
 907         struct list_head *cur, *tmp;
 908         struct vmbus_channel *cur_channel;
 909
 910         if (primary_channel->sc_creation_callback == NULL)
 911                 return;
 912
 913         list_for_each_safe(cur, tmp, &primary_channel->sc_list) {
 914                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 915
 916                 primary_channel->sc_creation_callback(cur_channel);
 917         }
 918 }
 919
 920 void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
 921                                 void (*sc_cr_cb)(struct vmbus_channel *new_sc))
 922 {
 923         primary_channel->sc_creation_callback = sc_cr_cb;
 924 }
 925 EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
 926
 927 bool vmbus_are_subchannels_present(struct vmbus_channel *primary)
 928 {
 929         bool ret;
 930
 931         ret = !list_empty(&primary->sc_list);
 932
 933         if (ret) {
 934                 /*
 935                  * Invoke the callback on sub-channel creation.
 936                  * This will present a uniform interface to the
 937                  * clients.
 938                  */
 939                 invoke_sc_cb(primary);
 940         }
 941
 942         return ret;
 943 }
 944 EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present);