linux/drivers/hv/channel_mgmt.c
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   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
  35struct vmbus_channel_message_table_entry {
  36        enum vmbus_channel_message_type message_type;
  37        void (*message_handler)(struct vmbus_channel_message_header *msg);
  38};
  39
  40
  41/**
  42 * vmbus_prep_negotiate_resp() - Create default response for Hyper-V Negotiate message
  43 * @icmsghdrp: Pointer to msg header structure
  44 * @icmsg_negotiate: Pointer to negotiate message structure
  45 * @buf: Raw buffer channel data
  46 *
  47 * @icmsghdrp is of type &struct icmsg_hdr.
  48 * @negop is of type &struct icmsg_negotiate.
  49 * Set up and fill in default negotiate response message.
  50 *
  51 * The fw_version specifies the  framework version that
  52 * we can support and srv_version specifies the service
  53 * version we can support.
  54 *
  55 * Mainly used by Hyper-V drivers.
  56 */
  57bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
  58                                struct icmsg_negotiate *negop, u8 *buf,
  59                                int fw_version, int srv_version)
  60{
  61        int icframe_major, icframe_minor;
  62        int icmsg_major, icmsg_minor;
  63        int fw_major, fw_minor;
  64        int srv_major, srv_minor;
  65        int i;
  66        bool found_match = false;
  67
  68        icmsghdrp->icmsgsize = 0x10;
  69        fw_major = (fw_version >> 16);
  70        fw_minor = (fw_version & 0xFFFF);
  71
  72        srv_major = (srv_version >> 16);
  73        srv_minor = (srv_version & 0xFFFF);
  74
  75        negop = (struct icmsg_negotiate *)&buf[
  76                sizeof(struct vmbuspipe_hdr) +
  77                sizeof(struct icmsg_hdr)];
  78
  79        icframe_major = negop->icframe_vercnt;
  80        icframe_minor = 0;
  81
  82        icmsg_major = negop->icmsg_vercnt;
  83        icmsg_minor = 0;
  84
  85        /*
  86         * Select the framework version number we will
  87         * support.
  88         */
  89
  90        for (i = 0; i < negop->icframe_vercnt; i++) {
  91                if ((negop->icversion_data[i].major == fw_major) &&
  92                   (negop->icversion_data[i].minor == fw_minor)) {
  93                        icframe_major = negop->icversion_data[i].major;
  94                        icframe_minor = negop->icversion_data[i].minor;
  95                        found_match = true;
  96                }
  97        }
  98
  99        if (!found_match)
 100                goto fw_error;
 101
 102        found_match = false;
 103
 104        for (i = negop->icframe_vercnt;
 105                 (i < negop->icframe_vercnt + negop->icmsg_vercnt); i++) {
 106                if ((negop->icversion_data[i].major == srv_major) &&
 107                   (negop->icversion_data[i].minor == srv_minor)) {
 108                        icmsg_major = negop->icversion_data[i].major;
 109                        icmsg_minor = negop->icversion_data[i].minor;
 110                        found_match = true;
 111                }
 112        }
 113
 114        /*
 115         * Respond with the framework and service
 116         * version numbers we can support.
 117         */
 118
 119fw_error:
 120        if (!found_match) {
 121                negop->icframe_vercnt = 0;
 122                negop->icmsg_vercnt = 0;
 123        } else {
 124                negop->icframe_vercnt = 1;
 125                negop->icmsg_vercnt = 1;
 126        }
 127
 128        negop->icversion_data[0].major = icframe_major;
 129        negop->icversion_data[0].minor = icframe_minor;
 130        negop->icversion_data[1].major = icmsg_major;
 131        negop->icversion_data[1].minor = icmsg_minor;
 132        return found_match;
 133}
 134
 135EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);
 136
 137/*
 138 * alloc_channel - Allocate and initialize a vmbus channel object
 139 */
 140static struct vmbus_channel *alloc_channel(void)
 141{
 142        struct vmbus_channel *channel;
 143
 144        channel = kzalloc(sizeof(*channel), GFP_ATOMIC);
 145        if (!channel)
 146                return NULL;
 147
 148        spin_lock_init(&channel->inbound_lock);
 149        spin_lock_init(&channel->sc_lock);
 150
 151        INIT_LIST_HEAD(&channel->sc_list);
 152
 153        channel->controlwq = create_workqueue("hv_vmbus_ctl");
 154        if (!channel->controlwq) {
 155                kfree(channel);
 156                return NULL;
 157        }
 158
 159        return channel;
 160}
 161
 162/*
 163 * release_hannel - Release the vmbus channel object itself
 164 */
 165static void release_channel(struct work_struct *work)
 166{
 167        struct vmbus_channel *channel = container_of(work,
 168                                                     struct vmbus_channel,
 169                                                     work);
 170
 171        destroy_workqueue(channel->controlwq);
 172
 173        kfree(channel);
 174}
 175
 176/*
 177 * free_channel - Release the resources used by the vmbus channel object
 178 */
 179static void free_channel(struct vmbus_channel *channel)
 180{
 181
 182        /*
 183         * We have to release the channel's workqueue/thread in the vmbus's
 184         * workqueue/thread context
 185         * ie we can't destroy ourselves.
 186         */
 187        INIT_WORK(&channel->work, release_channel);
 188        queue_work(vmbus_connection.work_queue, &channel->work);
 189}
 190
 191
 192
 193/*
 194 * vmbus_process_rescind_offer -
 195 * Rescind the offer by initiating a device removal
 196 */
 197static void vmbus_process_rescind_offer(struct work_struct *work)
 198{
 199        struct vmbus_channel *channel = container_of(work,
 200                                                     struct vmbus_channel,
 201                                                     work);
 202        unsigned long flags;
 203        struct vmbus_channel *primary_channel;
 204        struct vmbus_channel_relid_released msg;
 205
 206        vmbus_device_unregister(channel->device_obj);
 207        memset(&msg, 0, sizeof(struct vmbus_channel_relid_released));
 208        msg.child_relid = channel->offermsg.child_relid;
 209        msg.header.msgtype = CHANNELMSG_RELID_RELEASED;
 210        vmbus_post_msg(&msg, sizeof(struct vmbus_channel_relid_released));
 211
 212        if (channel->primary_channel == NULL) {
 213                spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 214                list_del(&channel->listentry);
 215                spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 216        } else {
 217                primary_channel = channel->primary_channel;
 218                spin_lock_irqsave(&primary_channel->sc_lock, flags);
 219                list_del(&channel->listentry);
 220                spin_unlock_irqrestore(&primary_channel->sc_lock, flags);
 221        }
 222        free_channel(channel);
 223}
 224
 225void vmbus_free_channels(void)
 226{
 227        struct vmbus_channel *channel;
 228
 229        list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 230                vmbus_device_unregister(channel->device_obj);
 231                kfree(channel->device_obj);
 232                free_channel(channel);
 233        }
 234}
 235
 236/*
 237 * vmbus_process_offer - Process the offer by creating a channel/device
 238 * associated with this offer
 239 */
 240static void vmbus_process_offer(struct work_struct *work)
 241{
 242        struct vmbus_channel *newchannel = container_of(work,
 243                                                        struct vmbus_channel,
 244                                                        work);
 245        struct vmbus_channel *channel;
 246        bool fnew = true;
 247        int ret;
 248        unsigned long flags;
 249
 250        /* The next possible work is rescind handling */
 251        INIT_WORK(&newchannel->work, vmbus_process_rescind_offer);
 252
 253        /* Make sure this is a new offer */
 254        spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 255
 256        list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 257                if (!uuid_le_cmp(channel->offermsg.offer.if_type,
 258                        newchannel->offermsg.offer.if_type) &&
 259                        !uuid_le_cmp(channel->offermsg.offer.if_instance,
 260                                newchannel->offermsg.offer.if_instance)) {
 261                        fnew = false;
 262                        break;
 263                }
 264        }
 265
 266        if (fnew)
 267                list_add_tail(&newchannel->listentry,
 268                              &vmbus_connection.chn_list);
 269
 270        spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 271
 272        if (!fnew) {
 273                /*
 274                 * Check to see if this is a sub-channel.
 275                 */
 276                if (newchannel->offermsg.offer.sub_channel_index != 0) {
 277                        /*
 278                         * Process the sub-channel.
 279                         */
 280                        newchannel->primary_channel = channel;
 281                        spin_lock_irqsave(&channel->sc_lock, flags);
 282                        list_add_tail(&newchannel->sc_list, &channel->sc_list);
 283                        spin_unlock_irqrestore(&channel->sc_lock, flags);
 284                        newchannel->state = CHANNEL_OPEN_STATE;
 285                        if (channel->sc_creation_callback != NULL)
 286                                channel->sc_creation_callback(newchannel);
 287
 288                        return;
 289                }
 290
 291                free_channel(newchannel);
 292                return;
 293        }
 294
 295        /*
 296         * This state is used to indicate a successful open
 297         * so that when we do close the channel normally, we
 298         * can cleanup properly
 299         */
 300        newchannel->state = CHANNEL_OPEN_STATE;
 301
 302        /*
 303         * Start the process of binding this offer to the driver
 304         * We need to set the DeviceObject field before calling
 305         * vmbus_child_dev_add()
 306         */
 307        newchannel->device_obj = vmbus_device_create(
 308                &newchannel->offermsg.offer.if_type,
 309                &newchannel->offermsg.offer.if_instance,
 310                newchannel);
 311
 312        /*
 313         * Add the new device to the bus. This will kick off device-driver
 314         * binding which eventually invokes the device driver's AddDevice()
 315         * method.
 316         */
 317        ret = vmbus_device_register(newchannel->device_obj);
 318        if (ret != 0) {
 319                pr_err("unable to add child device object (relid %d)\n",
 320                           newchannel->offermsg.child_relid);
 321
 322                spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
 323                list_del(&newchannel->listentry);
 324                spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
 325                kfree(newchannel->device_obj);
 326
 327                free_channel(newchannel);
 328        }
 329}
 330
 331enum {
 332        IDE = 0,
 333        SCSI,
 334        NIC,
 335        MAX_PERF_CHN,
 336};
 337
 338/*
 339 * This is an array of device_ids (device types) that are performance critical.
 340 * We attempt to distribute the interrupt load for these devices across
 341 * all available CPUs.
 342 */
 343static const struct hv_vmbus_device_id hp_devs[] = {
 344        /* IDE */
 345        { HV_IDE_GUID, },
 346        /* Storage - SCSI */
 347        { HV_SCSI_GUID, },
 348        /* Network */
 349        { HV_NIC_GUID, },
 350};
 351
 352
 353/*
 354 * We use this state to statically distribute the channel interrupt load.
 355 */
 356static u32  next_vp;
 357
 358/*
 359 * Starting with Win8, we can statically distribute the incoming
 360 * channel interrupt load by binding a channel to VCPU. We
 361 * implement here a simple round robin scheme for distributing
 362 * the interrupt load.
 363 * We will bind channels that are not performance critical to cpu 0 and
 364 * performance critical channels (IDE, SCSI and Network) will be uniformly
 365 * distributed across all available CPUs.
 366 */
 367static u32 get_vp_index(uuid_le *type_guid)
 368{
 369        u32 cur_cpu;
 370        int i;
 371        bool perf_chn = false;
 372        u32 max_cpus = num_online_cpus();
 373
 374        for (i = IDE; i < MAX_PERF_CHN; i++) {
 375                if (!memcmp(type_guid->b, hp_devs[i].guid,
 376                                 sizeof(uuid_le))) {
 377                        perf_chn = true;
 378                        break;
 379                }
 380        }
 381        if ((vmbus_proto_version == VERSION_WS2008) ||
 382            (vmbus_proto_version == VERSION_WIN7) || (!perf_chn)) {
 383                /*
 384                 * Prior to win8, all channel interrupts are
 385                 * delivered on cpu 0.
 386                 * Also if the channel is not a performance critical
 387                 * channel, bind it to cpu 0.
 388                 */
 389                return 0;
 390        }
 391        cur_cpu = (++next_vp % max_cpus);
 392        return hv_context.vp_index[cur_cpu];
 393}
 394
 395/*
 396 * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 397 *
 398 */
 399static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 400{
 401        struct vmbus_channel_offer_channel *offer;
 402        struct vmbus_channel *newchannel;
 403
 404        offer = (struct vmbus_channel_offer_channel *)hdr;
 405
 406        /* Allocate the channel object and save this offer. */
 407        newchannel = alloc_channel();
 408        if (!newchannel) {
 409                pr_err("Unable to allocate channel object\n");
 410                return;
 411        }
 412
 413        /*
 414         * By default we setup state to enable batched
 415         * reading. A specific service can choose to
 416         * disable this prior to opening the channel.
 417         */
 418        newchannel->batched_reading = true;
 419
 420        /*
 421         * Setup state for signalling the host.
 422         */
 423        newchannel->sig_event = (struct hv_input_signal_event *)
 424                                (ALIGN((unsigned long)
 425                                &newchannel->sig_buf,
 426                                HV_HYPERCALL_PARAM_ALIGN));
 427
 428        newchannel->sig_event->connectionid.asu32 = 0;
 429        newchannel->sig_event->connectionid.u.id = VMBUS_EVENT_CONNECTION_ID;
 430        newchannel->sig_event->flag_number = 0;
 431        newchannel->sig_event->rsvdz = 0;
 432
 433        if (vmbus_proto_version != VERSION_WS2008) {
 434                newchannel->is_dedicated_interrupt =
 435                                (offer->is_dedicated_interrupt != 0);
 436                newchannel->sig_event->connectionid.u.id =
 437                                offer->connection_id;
 438        }
 439
 440        newchannel->target_vp = get_vp_index(&offer->offer.if_type);
 441
 442        memcpy(&newchannel->offermsg, offer,
 443               sizeof(struct vmbus_channel_offer_channel));
 444        newchannel->monitor_grp = (u8)offer->monitorid / 32;
 445        newchannel->monitor_bit = (u8)offer->monitorid % 32;
 446
 447        INIT_WORK(&newchannel->work, vmbus_process_offer);
 448        queue_work(newchannel->controlwq, &newchannel->work);
 449}
 450
 451/*
 452 * vmbus_onoffer_rescind - Rescind offer handler.
 453 *
 454 * We queue a work item to process this offer synchronously
 455 */
 456static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
 457{
 458        struct vmbus_channel_rescind_offer *rescind;
 459        struct vmbus_channel *channel;
 460
 461        rescind = (struct vmbus_channel_rescind_offer *)hdr;
 462        channel = relid2channel(rescind->child_relid);
 463
 464        if (channel == NULL)
 465                /* Just return here, no channel found */
 466                return;
 467
 468        /* work is initialized for vmbus_process_rescind_offer() from
 469         * vmbus_process_offer() where the channel got created */
 470        queue_work(channel->controlwq, &channel->work);
 471}
 472
 473/*
 474 * vmbus_onoffers_delivered -
 475 * This is invoked when all offers have been delivered.
 476 *
 477 * Nothing to do here.
 478 */
 479static void vmbus_onoffers_delivered(
 480                        struct vmbus_channel_message_header *hdr)
 481{
 482}
 483
 484/*
 485 * vmbus_onopen_result - Open result handler.
 486 *
 487 * This is invoked when we received a response to our channel open request.
 488 * Find the matching request, copy the response and signal the requesting
 489 * thread.
 490 */
 491static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
 492{
 493        struct vmbus_channel_open_result *result;
 494        struct vmbus_channel_msginfo *msginfo;
 495        struct vmbus_channel_message_header *requestheader;
 496        struct vmbus_channel_open_channel *openmsg;
 497        unsigned long flags;
 498
 499        result = (struct vmbus_channel_open_result *)hdr;
 500
 501        /*
 502         * Find the open msg, copy the result and signal/unblock the wait event
 503         */
 504        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 505
 506        list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 507                                msglistentry) {
 508                requestheader =
 509                        (struct vmbus_channel_message_header *)msginfo->msg;
 510
 511                if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
 512                        openmsg =
 513                        (struct vmbus_channel_open_channel *)msginfo->msg;
 514                        if (openmsg->child_relid == result->child_relid &&
 515                            openmsg->openid == result->openid) {
 516                                memcpy(&msginfo->response.open_result,
 517                                       result,
 518                                       sizeof(
 519                                        struct vmbus_channel_open_result));
 520                                complete(&msginfo->waitevent);
 521                                break;
 522                        }
 523                }
 524        }
 525        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 526}
 527
 528/*
 529 * vmbus_ongpadl_created - GPADL created handler.
 530 *
 531 * This is invoked when we received a response to our gpadl create request.
 532 * Find the matching request, copy the response and signal the requesting
 533 * thread.
 534 */
 535static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
 536{
 537        struct vmbus_channel_gpadl_created *gpadlcreated;
 538        struct vmbus_channel_msginfo *msginfo;
 539        struct vmbus_channel_message_header *requestheader;
 540        struct vmbus_channel_gpadl_header *gpadlheader;
 541        unsigned long flags;
 542
 543        gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
 544
 545        /*
 546         * Find the establish msg, copy the result and signal/unblock the wait
 547         * event
 548         */
 549        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 550
 551        list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 552                                msglistentry) {
 553                requestheader =
 554                        (struct vmbus_channel_message_header *)msginfo->msg;
 555
 556                if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
 557                        gpadlheader =
 558                        (struct vmbus_channel_gpadl_header *)requestheader;
 559
 560                        if ((gpadlcreated->child_relid ==
 561                             gpadlheader->child_relid) &&
 562                            (gpadlcreated->gpadl == gpadlheader->gpadl)) {
 563                                memcpy(&msginfo->response.gpadl_created,
 564                                       gpadlcreated,
 565                                       sizeof(
 566                                        struct vmbus_channel_gpadl_created));
 567                                complete(&msginfo->waitevent);
 568                                break;
 569                        }
 570                }
 571        }
 572        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 573}
 574
 575/*
 576 * vmbus_ongpadl_torndown - GPADL torndown handler.
 577 *
 578 * This is invoked when we received a response to our gpadl teardown request.
 579 * Find the matching request, copy the response and signal the requesting
 580 * thread.
 581 */
 582static void vmbus_ongpadl_torndown(
 583                        struct vmbus_channel_message_header *hdr)
 584{
 585        struct vmbus_channel_gpadl_torndown *gpadl_torndown;
 586        struct vmbus_channel_msginfo *msginfo;
 587        struct vmbus_channel_message_header *requestheader;
 588        struct vmbus_channel_gpadl_teardown *gpadl_teardown;
 589        unsigned long flags;
 590
 591        gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
 592
 593        /*
 594         * Find the open msg, copy the result and signal/unblock the wait event
 595         */
 596        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 597
 598        list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 599                                msglistentry) {
 600                requestheader =
 601                        (struct vmbus_channel_message_header *)msginfo->msg;
 602
 603                if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
 604                        gpadl_teardown =
 605                        (struct vmbus_channel_gpadl_teardown *)requestheader;
 606
 607                        if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
 608                                memcpy(&msginfo->response.gpadl_torndown,
 609                                       gpadl_torndown,
 610                                       sizeof(
 611                                        struct vmbus_channel_gpadl_torndown));
 612                                complete(&msginfo->waitevent);
 613                                break;
 614                        }
 615                }
 616        }
 617        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 618}
 619
 620/*
 621 * vmbus_onversion_response - Version response handler
 622 *
 623 * This is invoked when we received a response to our initiate contact request.
 624 * Find the matching request, copy the response and signal the requesting
 625 * thread.
 626 */
 627static void vmbus_onversion_response(
 628                struct vmbus_channel_message_header *hdr)
 629{
 630        struct vmbus_channel_msginfo *msginfo;
 631        struct vmbus_channel_message_header *requestheader;
 632        struct vmbus_channel_version_response *version_response;
 633        unsigned long flags;
 634
 635        version_response = (struct vmbus_channel_version_response *)hdr;
 636        spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 637
 638        list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 639                                msglistentry) {
 640                requestheader =
 641                        (struct vmbus_channel_message_header *)msginfo->msg;
 642
 643                if (requestheader->msgtype ==
 644                    CHANNELMSG_INITIATE_CONTACT) {
 645                        memcpy(&msginfo->response.version_response,
 646                              version_response,
 647                              sizeof(struct vmbus_channel_version_response));
 648                        complete(&msginfo->waitevent);
 649                }
 650        }
 651        spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 652}
 653
 654/* Channel message dispatch table */
 655static struct vmbus_channel_message_table_entry
 656        channel_message_table[CHANNELMSG_COUNT] = {
 657        {CHANNELMSG_INVALID,                    NULL},
 658        {CHANNELMSG_OFFERCHANNEL,               vmbus_onoffer},
 659        {CHANNELMSG_RESCIND_CHANNELOFFER,       vmbus_onoffer_rescind},
 660        {CHANNELMSG_REQUESTOFFERS,              NULL},
 661        {CHANNELMSG_ALLOFFERS_DELIVERED,        vmbus_onoffers_delivered},
 662        {CHANNELMSG_OPENCHANNEL,                NULL},
 663        {CHANNELMSG_OPENCHANNEL_RESULT, vmbus_onopen_result},
 664        {CHANNELMSG_CLOSECHANNEL,               NULL},
 665        {CHANNELMSG_GPADL_HEADER,               NULL},
 666        {CHANNELMSG_GPADL_BODY,         NULL},
 667        {CHANNELMSG_GPADL_CREATED,              vmbus_ongpadl_created},
 668        {CHANNELMSG_GPADL_TEARDOWN,             NULL},
 669        {CHANNELMSG_GPADL_TORNDOWN,             vmbus_ongpadl_torndown},
 670        {CHANNELMSG_RELID_RELEASED,             NULL},
 671        {CHANNELMSG_INITIATE_CONTACT,           NULL},
 672        {CHANNELMSG_VERSION_RESPONSE,           vmbus_onversion_response},
 673        {CHANNELMSG_UNLOAD,                     NULL},
 674};
 675
 676/*
 677 * vmbus_onmessage - Handler for channel protocol messages.
 678 *
 679 * This is invoked in the vmbus worker thread context.
 680 */
 681void vmbus_onmessage(void *context)
 682{
 683        struct hv_message *msg = context;
 684        struct vmbus_channel_message_header *hdr;
 685        int size;
 686
 687        hdr = (struct vmbus_channel_message_header *)msg->u.payload;
 688        size = msg->header.payload_size;
 689
 690        if (hdr->msgtype >= CHANNELMSG_COUNT) {
 691                pr_err("Received invalid channel message type %d size %d\n",
 692                           hdr->msgtype, size);
 693                print_hex_dump_bytes("", DUMP_PREFIX_NONE,
 694                                     (unsigned char *)msg->u.payload, size);
 695                return;
 696        }
 697
 698        if (channel_message_table[hdr->msgtype].message_handler)
 699                channel_message_table[hdr->msgtype].message_handler(hdr);
 700        else
 701                pr_err("Unhandled channel message type %d\n", hdr->msgtype);
 702}
 703
 704/*
 705 * vmbus_request_offers - Send a request to get all our pending offers.
 706 */
 707int vmbus_request_offers(void)
 708{
 709        struct vmbus_channel_message_header *msg;
 710        struct vmbus_channel_msginfo *msginfo;
 711        int ret, t;
 712
 713        msginfo = kmalloc(sizeof(*msginfo) +
 714                          sizeof(struct vmbus_channel_message_header),
 715                          GFP_KERNEL);
 716        if (!msginfo)
 717                return -ENOMEM;
 718
 719        init_completion(&msginfo->waitevent);
 720
 721        msg = (struct vmbus_channel_message_header *)msginfo->msg;
 722
 723        msg->msgtype = CHANNELMSG_REQUESTOFFERS;
 724
 725
 726        ret = vmbus_post_msg(msg,
 727                               sizeof(struct vmbus_channel_message_header));
 728        if (ret != 0) {
 729                pr_err("Unable to request offers - %d\n", ret);
 730
 731                goto cleanup;
 732        }
 733
 734        t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
 735        if (t == 0) {
 736                ret = -ETIMEDOUT;
 737                goto cleanup;
 738        }
 739
 740
 741
 742cleanup:
 743        kfree(msginfo);
 744
 745        return ret;
 746}
 747
 748/*
 749 * Retrieve the (sub) channel on which to send an outgoing request.
 750 * When a primary channel has multiple sub-channels, we choose a
 751 * channel whose VCPU binding is closest to the VCPU on which
 752 * this call is being made.
 753 */
 754struct vmbus_channel *vmbus_get_outgoing_channel(struct vmbus_channel *primary)
 755{
 756        struct list_head *cur, *tmp;
 757        int cur_cpu = hv_context.vp_index[smp_processor_id()];
 758        struct vmbus_channel *cur_channel;
 759        struct vmbus_channel *outgoing_channel = primary;
 760        int cpu_distance, new_cpu_distance;
 761
 762        if (list_empty(&primary->sc_list))
 763                return outgoing_channel;
 764
 765        list_for_each_safe(cur, tmp, &primary->sc_list) {
 766                cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 767                if (cur_channel->state != CHANNEL_OPENED_STATE)
 768                        continue;
 769
 770                if (cur_channel->target_vp == cur_cpu)
 771                        return cur_channel;
 772
 773                cpu_distance = ((outgoing_channel->target_vp > cur_cpu) ?
 774                                (outgoing_channel->target_vp - cur_cpu) :
 775                                (cur_cpu - outgoing_channel->target_vp));
 776
 777                new_cpu_distance = ((cur_channel->target_vp > cur_cpu) ?
 778                                (cur_channel->target_vp - cur_cpu) :
 779                                (cur_cpu - cur_channel->target_vp));
 780
 781                if (cpu_distance < new_cpu_distance)
 782                        continue;
 783
 784                outgoing_channel = cur_channel;
 785        }
 786
 787        return outgoing_channel;
 788}
 789EXPORT_SYMBOL_GPL(vmbus_get_outgoing_channel);
 790
 791static void invoke_sc_cb(struct vmbus_channel *primary_channel)
 792{
 793        struct list_head *cur, *tmp;
 794        struct vmbus_channel *cur_channel;
 795
 796        if (primary_channel->sc_creation_callback == NULL)
 797                return;
 798
 799        list_for_each_safe(cur, tmp, &primary_channel->sc_list) {
 800                cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 801
 802                primary_channel->sc_creation_callback(cur_channel);
 803        }
 804}
 805
 806void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
 807                                void (*sc_cr_cb)(struct vmbus_channel *new_sc))
 808{
 809        primary_channel->sc_creation_callback = sc_cr_cb;
 810}
 811EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
 812
 813bool vmbus_are_subchannels_present(struct vmbus_channel *primary)
 814{
 815        bool ret;
 816
 817        ret = !list_empty(&primary->sc_list);
 818
 819        if (ret) {
 820                /*
 821                 * Invoke the callback on sub-channel creation.
 822                 * This will present a uniform interface to the
 823                 * clients.
 824                 */
 825                invoke_sc_cb(primary);
 826        }
 827
 828        return ret;
 829}
 830EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present);
 831
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