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         unsigned long flags;
 237
 238         /* Make sure this is a new offer */
 239         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 240
 241         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 242                 if (!uuid_le_cmp(channel->offermsg.offer.if_type,
 243                         newchannel->offermsg.offer.if_type) &&
 244                         !uuid_le_cmp(channel->offermsg.offer.if_instance,
 245                                 newchannel->offermsg.offer.if_instance)) {
 246                         fnew = false;
 247                         break;
 248                 }
 249         }
 250
 251         if (fnew)
 252                 list_add_tail(&newchannel->listentry,
 253                               &vmbus_connection.chn_list);
 254
 255         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 256
 257         if (!fnew) {
 258                 /*
 259                  * Check to see if this is a sub-channel.
 260                  */
 261                 if (newchannel->offermsg.offer.sub_channel_index != 0) {
 262                         /*
 263                          * Process the sub-channel.
 264                          */
 265                         newchannel->primary_channel = channel;
 266                         spin_lock_irqsave(&channel->lock, flags);
 267                         list_add_tail(&newchannel->sc_list, &channel->sc_list);
 268                         spin_unlock_irqrestore(&channel->lock, flags);
 269                         channel->num_sc++;
 270                 } else
 271                         goto err_free_chan;
 272         }
 273
 274         if (newchannel->target_cpu != get_cpu()) {
 275                 put_cpu();
 276                 smp_call_function_single(newchannel->target_cpu,
 277                                          percpu_channel_enq,
 278                                          newchannel, true);
 279         } else {
 280                 percpu_channel_enq(newchannel);
 281                 put_cpu();
 282         }
 283
 284         /*
 285          * This state is used to indicate a successful open
 286          * so that when we do close the channel normally, we
 287          * can cleanup properly
 288          */
 289         newchannel->state = CHANNEL_OPEN_STATE;
 290
 291         if (!fnew) {
 292                 if (channel->sc_creation_callback != NULL)
 293                         channel->sc_creation_callback(newchannel);
 294                 return;
 295         }
 296
 297         /*
 298          * Start the process of binding this offer to the driver
 299          * We need to set the DeviceObject field before calling
 300          * vmbus_child_dev_add()
 301          */
 302         newchannel->device_obj = vmbus_device_create(
 303                 &newchannel->offermsg.offer.if_type,
 304                 &newchannel->offermsg.offer.if_instance,
 305                 newchannel);
 306         if (!newchannel->device_obj)
 307                 goto err_deq_chan;
 308
 309         /*
 310          * Add the new device to the bus. This will kick off device-driver
 311          * binding which eventually invokes the device driver's AddDevice()
 312          * method.
 313          */
 314         if (vmbus_device_register(newchannel->device_obj) != 0) {
 315                 pr_err("unable to add child device object (relid %d)\n",
 316                         newchannel->offermsg.child_relid);
 317                 kfree(newchannel->device_obj);
 318                 goto err_deq_chan;
 319         }
 320         return;
 321
 322 err_deq_chan:
 323         spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 324         list_del(&newchannel->listentry);
 325         spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 326
 327         if (newchannel->target_cpu != get_cpu()) {
 328                 put_cpu();
 329                 smp_call_function_single(newchannel->target_cpu,
 330                                          percpu_channel_deq, newchannel, true);
 331         } else {
 332                 percpu_channel_deq(newchannel);
 333                 put_cpu();
 334         }
 335
 336 err_free_chan:
 337         free_channel(newchannel);
 338 }
 339
 340 enum {
 341         IDE = 0,
 342         SCSI,
 343         NIC,
 344         MAX_PERF_CHN,
 345 };
 346
 347 /*
 348  * This is an array of device_ids (device types) that are performance critical.
 349  * We attempt to distribute the interrupt load for these devices across
 350  * all available CPUs.
 351  */
 352 static const struct hv_vmbus_device_id hp_devs[] = {
 353         /* IDE */
 354         { HV_IDE_GUID, },
 355         /* Storage - SCSI */
 356         { HV_SCSI_GUID, },
 357         /* Network */
 358         { HV_NIC_GUID, },
 359         /* NetworkDirect Guest RDMA */
 360         { HV_ND_GUID, },
 361 };
 362
 363
 364 /*
 365  * We use this state to statically distribute the channel interrupt load.
 366  */
 367 static u32  next_vp;
 368
 369 /*
 370  * Starting with Win8, we can statically distribute the incoming
 371  * channel interrupt load by binding a channel to VCPU. We
 372  * implement here a simple round robin scheme for distributing
 373  * the interrupt load.
 374  * We will bind channels that are not performance critical to cpu 0 and
 375  * performance critical channels (IDE, SCSI and Network) will be uniformly
 376  * distributed across all available CPUs.
 377  */
 378 static void init_vp_index(struct vmbus_channel *channel, const uuid_le *type_guid)
 379 {
 380         u32 cur_cpu;
 381         int i;
 382         bool perf_chn = false;
 383         u32 max_cpus = num_online_cpus();
 384
 385         for (i = IDE; i < MAX_PERF_CHN; i++) {
 386                 if (!memcmp(type_guid->b, hp_devs[i].guid,
 387                                  sizeof(uuid_le))) {
 388                         perf_chn = true;
 389                         break;
 390                 }
 391         }
 392         if ((vmbus_proto_version == VERSION_WS2008) ||
 393             (vmbus_proto_version == VERSION_WIN7) || (!perf_chn)) {
 394                 /*
 395                  * Prior to win8, all channel interrupts are
 396                  * delivered on cpu 0.
 397                  * Also if the channel is not a performance critical
 398                  * channel, bind it to cpu 0.
 399                  */
 400                 channel->target_cpu = 0;
 401                 channel->target_vp = 0;
 402                 return;
 403         }
 404         cur_cpu = (++next_vp % max_cpus);
 405         channel->target_cpu = cur_cpu;
 406         channel->target_vp = hv_context.vp_index[cur_cpu];
 407 }
 408
 409 /*
 410  * vmbus_unload_response - Handler for the unload response.
 411  */
 412 static void vmbus_unload_response(struct vmbus_channel_message_header *hdr)
 413 {
 414         /*
 415          * This is a global event; just wakeup the waiting thread.
 416          * Once we successfully unload, we can cleanup the monitor state.
 417          */
 418         complete(&vmbus_connection.unload_event);
 419 }
 420
 421 void vmbus_initiate_unload(void)
 422 {
 423         struct vmbus_channel_message_header hdr;
 424
 425         init_completion(&vmbus_connection.unload_event);
 426         memset(&hdr, 0, sizeof(struct vmbus_channel_message_header));
 427         hdr.msgtype = CHANNELMSG_UNLOAD;
 428         vmbus_post_msg(&hdr, sizeof(struct vmbus_channel_message_header));
 429
 430         wait_for_completion(&vmbus_connection.unload_event);
 431 }
 432
 433 /*
 434  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 435  *
 436  */
 437 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 438 {
 439         struct vmbus_channel_offer_channel *offer;
 440         struct vmbus_channel *newchannel;
 441
 442         offer = (struct vmbus_channel_offer_channel *)hdr;
 443
 444         /* Allocate the channel object and save this offer. */
 445         newchannel = alloc_channel();
 446         if (!newchannel) {
 447                 pr_err("Unable to allocate channel object\n");
 448                 return;
 449         }
 450
 451         /*
 452          * By default we setup state to enable batched
 453          * reading. A specific service can choose to
 454          * disable this prior to opening the channel.
 455          */
 456         newchannel->batched_reading = true;
 457
 458         /*
 459          * Setup state for signalling the host.
 460          */
 461         newchannel->sig_event = (struct hv_input_signal_event *)
 462                                 (ALIGN((unsigned long)
 463                                 &newchannel->sig_buf,
 464                                 HV_HYPERCALL_PARAM_ALIGN));
 465
 466         newchannel->sig_event->connectionid.asu32 = 0;
 467         newchannel->sig_event->connectionid.u.id = VMBUS_EVENT_CONNECTION_ID;
 468         newchannel->sig_event->flag_number = 0;
 469         newchannel->sig_event->rsvdz = 0;
 470
 471         if (vmbus_proto_version != VERSION_WS2008) {
 472                 newchannel->is_dedicated_interrupt =
 473                                 (offer->is_dedicated_interrupt != 0);
 474                 newchannel->sig_event->connectionid.u.id =
 475                                 offer->connection_id;
 476         }
 477
 478         init_vp_index(newchannel, &offer->offer.if_type);
 479
 480         memcpy(&newchannel->offermsg, offer,
 481                sizeof(struct vmbus_channel_offer_channel));
 482         newchannel->monitor_grp = (u8)offer->monitorid / 32;
 483         newchannel->monitor_bit = (u8)offer->monitorid % 32;
 484
 485         vmbus_process_offer(newchannel);
 486 }
 487
 488 /*
 489  * vmbus_onoffer_rescind - Rescind offer handler.
 490  *
 491  * We queue a work item to process this offer synchronously
 492  */
 493 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 494 {
 495         struct vmbus_channel_rescind_offer *rescind;
 496         struct vmbus_channel *channel;
 497         unsigned long flags;
 498         struct device *dev;
 499
 500         rescind = (struct vmbus_channel_rescind_offer *)hdr;
 501         channel = relid2channel(rescind->child_relid);
 502
 503         if (channel == NULL) {
 504                 hv_process_channel_removal(NULL, rescind->child_relid);
 505                 return;
 506         }
 507
 508         spin_lock_irqsave(&channel->lock, flags);
 509         channel->rescind = true;
 510         spin_unlock_irqrestore(&channel->lock, flags);
 511
 512         if (channel->device_obj) {
 513                 /*
 514                  * We will have to unregister this device from the
 515                  * driver core.
 516                  */
 517                 dev = get_device(&channel->device_obj->device);
 518                 if (dev) {
 519                         vmbus_device_unregister(channel->device_obj);
 520                         put_device(dev);
 521                 }
 522         } else {
 523                 hv_process_channel_removal(channel,
 524                         channel->offermsg.child_relid);
 525         }
 526 }
 527
 528 /*
 529  * vmbus_onoffers_delivered -
 530  * This is invoked when all offers have been delivered.
 531  *
 532  * Nothing to do here.
 533  */
 534 static void vmbus_onoffers_delivered(
 535                         struct vmbus_channel_message_header *hdr)
 536 {
 537 }
 538
 539 /*
 540  * vmbus_onopen_result - Open result handler.
 541  *
 542  * This is invoked when we received a response to our channel open request.
 543  * Find the matching request, copy the response and signal the requesting
 544  * thread.
 545  */
 546 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
 547 {
 548         struct vmbus_channel_open_result *result;
 549         struct vmbus_channel_msginfo *msginfo;
 550         struct vmbus_channel_message_header *requestheader;
 551         struct vmbus_channel_open_channel *openmsg;
 552         unsigned long flags;
 553
 554         result = (struct vmbus_channel_open_result *)hdr;
 555
 556         /*
 557          * Find the open msg, copy the result and signal/unblock the wait event
 558          */
 559         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 560
 561         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 562                                 msglistentry) {
 563                 requestheader =
 564                         (struct vmbus_channel_message_header *)msginfo->msg;
 565
 566                 if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
 567                         openmsg =
 568                         (struct vmbus_channel_open_channel *)msginfo->msg;
 569                         if (openmsg->child_relid == result->child_relid &&
 570                             openmsg->openid == result->openid) {
 571                                 memcpy(&msginfo->response.open_result,
 572                                        result,
 573                                        sizeof(
 574                                         struct vmbus_channel_open_result));
 575                                 complete(&msginfo->waitevent);
 576                                 break;
 577                         }
 578                 }
 579         }
 580         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 581 }
 582
 583 /*
 584  * vmbus_ongpadl_created - GPADL created handler.
 585  *
 586  * This is invoked when we received a response to our gpadl create request.
 587  * Find the matching request, copy the response and signal the requesting
 588  * thread.
 589  */
 590 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
 591 {
 592         struct vmbus_channel_gpadl_created *gpadlcreated;
 593         struct vmbus_channel_msginfo *msginfo;
 594         struct vmbus_channel_message_header *requestheader;
 595         struct vmbus_channel_gpadl_header *gpadlheader;
 596         unsigned long flags;
 597
 598         gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
 599
 600         /*
 601          * Find the establish msg, copy the result and signal/unblock the wait
 602          * event
 603          */
 604         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 605
 606         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 607                                 msglistentry) {
 608                 requestheader =
 609                         (struct vmbus_channel_message_header *)msginfo->msg;
 610
 611                 if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
 612                         gpadlheader =
 613                         (struct vmbus_channel_gpadl_header *)requestheader;
 614
 615                         if ((gpadlcreated->child_relid ==
 616                              gpadlheader->child_relid) &&
 617                             (gpadlcreated->gpadl == gpadlheader->gpadl)) {
 618                                 memcpy(&msginfo->response.gpadl_created,
 619                                        gpadlcreated,
 620                                        sizeof(
 621                                         struct vmbus_channel_gpadl_created));
 622                                 complete(&msginfo->waitevent);
 623                                 break;
 624                         }
 625                 }
 626         }
 627         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 628 }
 629
 630 /*
 631  * vmbus_ongpadl_torndown - GPADL torndown handler.
 632  *
 633  * This is invoked when we received a response to our gpadl teardown request.
 634  * Find the matching request, copy the response and signal the requesting
 635  * thread.
 636  */
 637 static void vmbus_ongpadl_torndown(
 638                         struct vmbus_channel_message_header *hdr)
 639 {
 640         struct vmbus_channel_gpadl_torndown *gpadl_torndown;
 641         struct vmbus_channel_msginfo *msginfo;
 642         struct vmbus_channel_message_header *requestheader;
 643         struct vmbus_channel_gpadl_teardown *gpadl_teardown;
 644         unsigned long flags;
 645
 646         gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
 647
 648         /*
 649          * Find the open msg, copy the result and signal/unblock the wait event
 650          */
 651         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 652
 653         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 654                                 msglistentry) {
 655                 requestheader =
 656                         (struct vmbus_channel_message_header *)msginfo->msg;
 657
 658                 if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
 659                         gpadl_teardown =
 660                         (struct vmbus_channel_gpadl_teardown *)requestheader;
 661
 662                         if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
 663                                 memcpy(&msginfo->response.gpadl_torndown,
 664                                        gpadl_torndown,
 665                                        sizeof(
 666                                         struct vmbus_channel_gpadl_torndown));
 667                                 complete(&msginfo->waitevent);
 668                                 break;
 669                         }
 670                 }
 671         }
 672         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 673 }
 674
 675 /*
 676  * vmbus_onversion_response - Version response handler
 677  *
 678  * This is invoked when we received a response to our initiate contact request.
 679  * Find the matching request, copy the response and signal the requesting
 680  * thread.
 681  */
 682 static void vmbus_onversion_response(
 683                 struct vmbus_channel_message_header *hdr)
 684 {
 685         struct vmbus_channel_msginfo *msginfo;
 686         struct vmbus_channel_message_header *requestheader;
 687         struct vmbus_channel_version_response *version_response;
 688         unsigned long flags;
 689
 690         version_response = (struct vmbus_channel_version_response *)hdr;
 691         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 692
 693         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 694                                 msglistentry) {
 695                 requestheader =
 696                         (struct vmbus_channel_message_header *)msginfo->msg;
 697
 698                 if (requestheader->msgtype ==
 699                     CHANNELMSG_INITIATE_CONTACT) {
 700                         memcpy(&msginfo->response.version_response,
 701                               version_response,
 702                               sizeof(struct vmbus_channel_version_response));
 703                         complete(&msginfo->waitevent);
 704                 }
 705         }
 706         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 707 }
 708
 709 /* Channel message dispatch table */
 710 struct vmbus_channel_message_table_entry
 711         channel_message_table[CHANNELMSG_COUNT] = {
 712         {CHANNELMSG_INVALID,                    0, NULL},
 713         {CHANNELMSG_OFFERCHANNEL,               0, vmbus_onoffer},
 714         {CHANNELMSG_RESCIND_CHANNELOFFER,       0, vmbus_onoffer_rescind},
 715         {CHANNELMSG_REQUESTOFFERS,              0, NULL},
 716         {CHANNELMSG_ALLOFFERS_DELIVERED,        1, vmbus_onoffers_delivered},
 717         {CHANNELMSG_OPENCHANNEL,                0, NULL},
 718         {CHANNELMSG_OPENCHANNEL_RESULT,         1, vmbus_onopen_result},
 719         {CHANNELMSG_CLOSECHANNEL,               0, NULL},
 720         {CHANNELMSG_GPADL_HEADER,               0, NULL},
 721         {CHANNELMSG_GPADL_BODY,                 0, NULL},
 722         {CHANNELMSG_GPADL_CREATED,              1, vmbus_ongpadl_created},
 723         {CHANNELMSG_GPADL_TEARDOWN,             0, NULL},
 724         {CHANNELMSG_GPADL_TORNDOWN,             1, vmbus_ongpadl_torndown},
 725         {CHANNELMSG_RELID_RELEASED,             0, NULL},
 726         {CHANNELMSG_INITIATE_CONTACT,           0, NULL},
 727         {CHANNELMSG_VERSION_RESPONSE,           1, vmbus_onversion_response},
 728         {CHANNELMSG_UNLOAD,                     0, NULL},
 729         {CHANNELMSG_UNLOAD_RESPONSE,            1, vmbus_unload_response},
 730 };
 731
 732 /*
 733  * vmbus_onmessage - Handler for channel protocol messages.
 734  *
 735  * This is invoked in the vmbus worker thread context.
 736  */
 737 void vmbus_onmessage(void *context)
 738 {
 739         struct hv_message *msg = context;
 740         struct vmbus_channel_message_header *hdr;
 741         int size;
 742
 743         hdr = (struct vmbus_channel_message_header *)msg->u.payload;
 744         size = msg->header.payload_size;
 745
 746         if (hdr->msgtype >= CHANNELMSG_COUNT) {
 747                 pr_err("Received invalid channel message type %d size %d\n",
 748                            hdr->msgtype, size);
 749                 print_hex_dump_bytes("", DUMP_PREFIX_NONE,
 750                                      (unsigned char *)msg->u.payload, size);
 751                 return;
 752         }
 753
 754         if (channel_message_table[hdr->msgtype].message_handler)
 755                 channel_message_table[hdr->msgtype].message_handler(hdr);
 756         else
 757                 pr_err("Unhandled channel message type %d\n", hdr->msgtype);
 758 }
 759
 760 /*
 761  * vmbus_request_offers - Send a request to get all our pending offers.
 762  */
 763 int vmbus_request_offers(void)
 764 {
 765         struct vmbus_channel_message_header *msg;
 766         struct vmbus_channel_msginfo *msginfo;
 767         int ret;
 768
 769         msginfo = kmalloc(sizeof(*msginfo) +
 770                           sizeof(struct vmbus_channel_message_header),
 771                           GFP_KERNEL);
 772         if (!msginfo)
 773                 return -ENOMEM;
 774
 775         msg = (struct vmbus_channel_message_header *)msginfo->msg;
 776
 777         msg->msgtype = CHANNELMSG_REQUESTOFFERS;
 778
 779
 780         ret = vmbus_post_msg(msg,
 781                                sizeof(struct vmbus_channel_message_header));
 782         if (ret != 0) {
 783                 pr_err("Unable to request offers - %d\n", ret);
 784
 785                 goto cleanup;
 786         }
 787
 788 cleanup:
 789         kfree(msginfo);
 790
 791         return ret;
 792 }
 793
 794 /*
 795  * Retrieve the (sub) channel on which to send an outgoing request.
 796  * When a primary channel has multiple sub-channels, we try to
 797  * distribute the load equally amongst all available channels.
 798  */
 799 struct vmbus_channel *vmbus_get_outgoing_channel(struct vmbus_channel *primary)
 800 {
 801         struct list_head *cur, *tmp;
 802         int cur_cpu;
 803         struct vmbus_channel *cur_channel;
 804         struct vmbus_channel *outgoing_channel = primary;
 805         int next_channel;
 806         int i = 1;
 807
 808         if (list_empty(&primary->sc_list))
 809                 return outgoing_channel;
 810
 811         next_channel = primary->next_oc++;
 812
 813         if (next_channel > (primary->num_sc)) {
 814                 primary->next_oc = 0;
 815                 return outgoing_channel;
 816         }
 817
 818         cur_cpu = hv_context.vp_index[get_cpu()];
 819         put_cpu();
 820         list_for_each_safe(cur, tmp, &primary->sc_list) {
 821                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 822                 if (cur_channel->state != CHANNEL_OPENED_STATE)
 823                         continue;
 824
 825                 if (cur_channel->target_vp == cur_cpu)
 826                         return cur_channel;
 827
 828                 if (i == next_channel)
 829                         return cur_channel;
 830
 831                 i++;
 832         }
 833
 834         return outgoing_channel;
 835 }
 836 EXPORT_SYMBOL_GPL(vmbus_get_outgoing_channel);
 837
 838 static void invoke_sc_cb(struct vmbus_channel *primary_channel)
 839 {
 840         struct list_head *cur, *tmp;
 841         struct vmbus_channel *cur_channel;
 842
 843         if (primary_channel->sc_creation_callback == NULL)
 844                 return;
 845
 846         list_for_each_safe(cur, tmp, &primary_channel->sc_list) {
 847                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 848
 849                 primary_channel->sc_creation_callback(cur_channel);
 850         }
 851 }
 852
 853 void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
 854                                 void (*sc_cr_cb)(struct vmbus_channel *new_sc))
 855 {
 856         primary_channel->sc_creation_callback = sc_cr_cb;
 857 }
 858 EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
 859
 860 bool vmbus_are_subchannels_present(struct vmbus_channel *primary)
 861 {
 862         bool ret;
 863
 864         ret = !list_empty(&primary->sc_list);
 865
 866         if (ret) {
 867                 /*
 868                  * Invoke the callback on sub-channel creation.
 869                  * This will present a uniform interface to the
 870                  * clients.
 871                  */
 872                 invoke_sc_cb(primary);
 873         }
 874
 875         return ret;
 876 }
 877 EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present);