drivers/hv/channel_mgmt.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2009, Microsoft Corporation.
   4  *
   5  * Authors:
   6  *   Haiyang Zhang <haiyangz@microsoft.com>
   7  *   Hank Janssen  <hjanssen@microsoft.com>
   8  */
   9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11 #include <linux/kernel.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/sched.h>
  14 #include <linux/wait.h>
  15 #include <linux/mm.h>
  16 #include <linux/slab.h>
  17 #include <linux/list.h>
  18 #include <linux/module.h>
  19 #include <linux/completion.h>
  20 #include <linux/delay.h>
  21 #include <linux/cpu.h>
  22 #include <linux/hyperv.h>
  23 #include <asm/mshyperv.h>
  24
  25 #include "hyperv_vmbus.h"
  26
  27 static void init_vp_index(struct vmbus_channel *channel);
  28
  29 const struct vmbus_device vmbus_devs[] = {
  30         /* IDE */
  31         { .dev_type = HV_IDE,
  32           HV_IDE_GUID,
  33           .perf_device = true,
  34         },
  35
  36         /* SCSI */
  37         { .dev_type = HV_SCSI,
  38           HV_SCSI_GUID,
  39           .perf_device = true,
  40         },
  41
  42         /* Fibre Channel */
  43         { .dev_type = HV_FC,
  44           HV_SYNTHFC_GUID,
  45           .perf_device = true,
  46         },
  47
  48         /* Synthetic NIC */
  49         { .dev_type = HV_NIC,
  50           HV_NIC_GUID,
  51           .perf_device = true,
  52         },
  53
  54         /* Network Direct */
  55         { .dev_type = HV_ND,
  56           HV_ND_GUID,
  57           .perf_device = true,
  58         },
  59
  60         /* PCIE */
  61         { .dev_type = HV_PCIE,
  62           HV_PCIE_GUID,
  63           .perf_device = false,
  64         },
  65
  66         /* Synthetic Frame Buffer */
  67         { .dev_type = HV_FB,
  68           HV_SYNTHVID_GUID,
  69           .perf_device = false,
  70         },
  71
  72         /* Synthetic Keyboard */
  73         { .dev_type = HV_KBD,
  74           HV_KBD_GUID,
  75           .perf_device = false,
  76         },
  77
  78         /* Synthetic MOUSE */
  79         { .dev_type = HV_MOUSE,
  80           HV_MOUSE_GUID,
  81           .perf_device = false,
  82         },
  83
  84         /* KVP */
  85         { .dev_type = HV_KVP,
  86           HV_KVP_GUID,
  87           .perf_device = false,
  88         },
  89
  90         /* Time Synch */
  91         { .dev_type = HV_TS,
  92           HV_TS_GUID,
  93           .perf_device = false,
  94         },
  95
  96         /* Heartbeat */
  97         { .dev_type = HV_HB,
  98           HV_HEART_BEAT_GUID,
  99           .perf_device = false,
 100         },
 101
 102         /* Shutdown */
 103         { .dev_type = HV_SHUTDOWN,
 104           HV_SHUTDOWN_GUID,
 105           .perf_device = false,
 106         },
 107
 108         /* File copy */
 109         { .dev_type = HV_FCOPY,
 110           HV_FCOPY_GUID,
 111           .perf_device = false,
 112         },
 113
 114         /* Backup */
 115         { .dev_type = HV_BACKUP,
 116           HV_VSS_GUID,
 117           .perf_device = false,
 118         },
 119
 120         /* Dynamic Memory */
 121         { .dev_type = HV_DM,
 122           HV_DM_GUID,
 123           .perf_device = false,
 124         },
 125
 126         /* Unknown GUID */
 127         { .dev_type = HV_UNKNOWN,
 128           .perf_device = false,
 129         },
 130 };
 131
 132 static const struct {
 133         guid_t guid;
 134 } vmbus_unsupported_devs[] = {
 135         { HV_AVMA1_GUID },
 136         { HV_AVMA2_GUID },
 137         { HV_RDV_GUID   },
 138 };
 139
 140 /*
 141  * The rescinded channel may be blocked waiting for a response from the host;
 142  * take care of that.
 143  */
 144 static void vmbus_rescind_cleanup(struct vmbus_channel *channel)
 145 {
 146         struct vmbus_channel_msginfo *msginfo;
 147         unsigned long flags;
 148
 149
 150         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 151         channel->rescind = true;
 152         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 153                                 msglistentry) {
 154
 155                 if (msginfo->waiting_channel == channel) {
 156                         complete(&msginfo->waitevent);
 157                         break;
 158                 }
 159         }
 160         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 161 }
 162
 163 static bool is_unsupported_vmbus_devs(const guid_t *guid)
 164 {
 165         int i;
 166
 167         for (i = 0; i < ARRAY_SIZE(vmbus_unsupported_devs); i++)
 168                 if (guid_equal(guid, &vmbus_unsupported_devs[i].guid))
 169                         return true;
 170         return false;
 171 }
 172
 173 static u16 hv_get_dev_type(const struct vmbus_channel *channel)
 174 {
 175         const guid_t *guid = &channel->offermsg.offer.if_type;
 176         u16 i;
 177
 178         if (is_hvsock_channel(channel) || is_unsupported_vmbus_devs(guid))
 179                 return HV_UNKNOWN;
 180
 181         for (i = HV_IDE; i < HV_UNKNOWN; i++) {
 182                 if (guid_equal(guid, &vmbus_devs[i].guid))
 183                         return i;
 184         }
 185         pr_info("Unknown GUID: %pUl\n", guid);
 186         return i;
 187 }
 188
 189 /**
 190  * vmbus_prep_negotiate_resp() - Create default response for Negotiate message
 191  * @icmsghdrp: Pointer to msg header structure
 192  * @buf: Raw buffer channel data
 193  * @fw_version: The framework versions we can support.
 194  * @fw_vercnt: The size of @fw_version.
 195  * @srv_version: The service versions we can support.
 196  * @srv_vercnt: The size of @srv_version.
 197  * @nego_fw_version: The selected framework version.
 198  * @nego_srv_version: The selected service version.
 199  *
 200  * Note: Versions are given in decreasing order.
 201  *
 202  * Set up and fill in default negotiate response message.
 203  * Mainly used by Hyper-V drivers.
 204  */
 205 bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp,
 206                                 u8 *buf, const int *fw_version, int fw_vercnt,
 207                                 const int *srv_version, int srv_vercnt,
 208                                 int *nego_fw_version, int *nego_srv_version)
 209 {
 210         int icframe_major, icframe_minor;
 211         int icmsg_major, icmsg_minor;
 212         int fw_major, fw_minor;
 213         int srv_major, srv_minor;
 214         int i, j;
 215         bool found_match = false;
 216         struct icmsg_negotiate *negop;
 217
 218         icmsghdrp->icmsgsize = 0x10;
 219         negop = (struct icmsg_negotiate *)&buf[
 220                 sizeof(struct vmbuspipe_hdr) +
 221                 sizeof(struct icmsg_hdr)];
 222
 223         icframe_major = negop->icframe_vercnt;
 224         icframe_minor = 0;
 225
 226         icmsg_major = negop->icmsg_vercnt;
 227         icmsg_minor = 0;
 228
 229         /*
 230          * Select the framework version number we will
 231          * support.
 232          */
 233
 234         for (i = 0; i < fw_vercnt; i++) {
 235                 fw_major = (fw_version[i] >> 16);
 236                 fw_minor = (fw_version[i] & 0xFFFF);
 237
 238                 for (j = 0; j < negop->icframe_vercnt; j++) {
 239                         if ((negop->icversion_data[j].major == fw_major) &&
 240                             (negop->icversion_data[j].minor == fw_minor)) {
 241                                 icframe_major = negop->icversion_data[j].major;
 242                                 icframe_minor = negop->icversion_data[j].minor;
 243                                 found_match = true;
 244                                 break;
 245                         }
 246                 }
 247
 248                 if (found_match)
 249                         break;
 250         }
 251
 252         if (!found_match)
 253                 goto fw_error;
 254
 255         found_match = false;
 256
 257         for (i = 0; i < srv_vercnt; i++) {
 258                 srv_major = (srv_version[i] >> 16);
 259                 srv_minor = (srv_version[i] & 0xFFFF);
 260
 261                 for (j = negop->icframe_vercnt;
 262                         (j < negop->icframe_vercnt + negop->icmsg_vercnt);
 263                         j++) {
 264
 265                         if ((negop->icversion_data[j].major == srv_major) &&
 266                                 (negop->icversion_data[j].minor == srv_minor)) {
 267
 268                                 icmsg_major = negop->icversion_data[j].major;
 269                                 icmsg_minor = negop->icversion_data[j].minor;
 270                                 found_match = true;
 271                                 break;
 272                         }
 273                 }
 274
 275                 if (found_match)
 276                         break;
 277         }
 278
 279         /*
 280          * Respond with the framework and service
 281          * version numbers we can support.
 282          */
 283
 284 fw_error:
 285         if (!found_match) {
 286                 negop->icframe_vercnt = 0;
 287                 negop->icmsg_vercnt = 0;
 288         } else {
 289                 negop->icframe_vercnt = 1;
 290                 negop->icmsg_vercnt = 1;
 291         }
 292
 293         if (nego_fw_version)
 294                 *nego_fw_version = (icframe_major << 16) | icframe_minor;
 295
 296         if (nego_srv_version)
 297                 *nego_srv_version = (icmsg_major << 16) | icmsg_minor;
 298
 299         negop->icversion_data[0].major = icframe_major;
 300         negop->icversion_data[0].minor = icframe_minor;
 301         negop->icversion_data[1].major = icmsg_major;
 302         negop->icversion_data[1].minor = icmsg_minor;
 303         return found_match;
 304 }
 305
 306 EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);
 307
 308 /*
 309  * alloc_channel - Allocate and initialize a vmbus channel object
 310  */
 311 static struct vmbus_channel *alloc_channel(void)
 312 {
 313         struct vmbus_channel *channel;
 314
 315         channel = kzalloc(sizeof(*channel), GFP_ATOMIC);
 316         if (!channel)
 317                 return NULL;
 318
 319         spin_lock_init(&channel->sched_lock);
 320         spin_lock_init(&channel->lock);
 321         init_completion(&channel->rescind_event);
 322
 323         INIT_LIST_HEAD(&channel->sc_list);
 324
 325         tasklet_init(&channel->callback_event,
 326                      vmbus_on_event, (unsigned long)channel);
 327
 328         hv_ringbuffer_pre_init(channel);
 329
 330         return channel;
 331 }
 332
 333 /*
 334  * free_channel - Release the resources used by the vmbus channel object
 335  */
 336 static void free_channel(struct vmbus_channel *channel)
 337 {
 338         tasklet_kill(&channel->callback_event);
 339         vmbus_remove_channel_attr_group(channel);
 340
 341         kobject_put(&channel->kobj);
 342 }
 343
 344 void vmbus_channel_map_relid(struct vmbus_channel *channel)
 345 {
 346         if (WARN_ON(channel->offermsg.child_relid >= MAX_CHANNEL_RELIDS))
 347                 return;
 348         /*
 349          * The mapping of the channel's relid is visible from the CPUs that
 350          * execute vmbus_chan_sched() by the time that vmbus_chan_sched() will
 351          * execute:
 352          *
 353          *  (a) In the "normal (i.e., not resuming from hibernation)" path,
 354          *      the full barrier in smp_store_mb() guarantees that the store
 355          *      is propagated to all CPUs before the add_channel_work work
 356          *      is queued.  In turn, add_channel_work is queued before the
 357          *      channel's ring buffer is allocated/initialized and the
 358          *      OPENCHANNEL message for the channel is sent in vmbus_open().
 359          *      Hyper-V won't start sending the interrupts for the channel
 360          *      before the OPENCHANNEL message is acked.  The memory barrier
 361          *      in vmbus_chan_sched() -> sync_test_and_clear_bit() ensures
 362          *      that vmbus_chan_sched() must find the channel's relid in
 363          *      recv_int_page before retrieving the channel pointer from the
 364          *      array of channels.
 365          *
 366          *  (b) In the "resuming from hibernation" path, the smp_store_mb()
 367          *      guarantees that the store is propagated to all CPUs before
 368          *      the VMBus connection is marked as ready for the resume event
 369          *      (cf. check_ready_for_resume_event()).  The interrupt handler
 370          *      of the VMBus driver and vmbus_chan_sched() can not run before
 371          *      vmbus_bus_resume() has completed execution (cf. resume_noirq).
 372          */
 373         smp_store_mb(
 374                 vmbus_connection.channels[channel->offermsg.child_relid],
 375                 channel);
 376 }
 377
 378 void vmbus_channel_unmap_relid(struct vmbus_channel *channel)
 379 {
 380         if (WARN_ON(channel->offermsg.child_relid >= MAX_CHANNEL_RELIDS))
 381                 return;
 382         WRITE_ONCE(
 383                 vmbus_connection.channels[channel->offermsg.child_relid],
 384                 NULL);
 385 }
 386
 387 static void vmbus_release_relid(u32 relid)
 388 {
 389         struct vmbus_channel_relid_released msg;
 390         int ret;
 391
 392         memset(&msg, 0, sizeof(struct vmbus_channel_relid_released));
 393         msg.child_relid = relid;
 394         msg.header.msgtype = CHANNELMSG_RELID_RELEASED;
 395         ret = vmbus_post_msg(&msg, sizeof(struct vmbus_channel_relid_released),
 396                              true);
 397
 398         trace_vmbus_release_relid(&msg, ret);
 399 }
 400
 401 void hv_process_channel_removal(struct vmbus_channel *channel)
 402 {
 403         unsigned long flags;
 404
 405         lockdep_assert_held(&vmbus_connection.channel_mutex);
 406         BUG_ON(!channel->rescind);
 407
 408         /*
 409          * hv_process_channel_removal() could find INVALID_RELID only for
 410          * hv_sock channels.  See the inline comments in vmbus_onoffer().
 411          */
 412         WARN_ON(channel->offermsg.child_relid == INVALID_RELID &&
 413                 !is_hvsock_channel(channel));
 414
 415         /*
 416          * Upon suspend, an in-use hv_sock channel is removed from the array of
 417          * channels and the relid is invalidated.  After hibernation, when the
 418          * user-space appplication destroys the channel, it's unnecessary and
 419          * unsafe to remove the channel from the array of channels.  See also
 420          * the inline comments before the call of vmbus_release_relid() below.
 421          */
 422         if (channel->offermsg.child_relid != INVALID_RELID)
 423                 vmbus_channel_unmap_relid(channel);
 424
 425         if (channel->primary_channel == NULL) {
 426                 list_del(&channel->listentry);
 427         } else {
 428                 struct vmbus_channel *primary_channel = channel->primary_channel;
 429                 spin_lock_irqsave(&primary_channel->lock, flags);
 430                 list_del(&channel->sc_list);
 431                 spin_unlock_irqrestore(&primary_channel->lock, flags);
 432         }
 433
 434         /*
 435          * If this is a "perf" channel, updates the hv_numa_map[] masks so that
 436          * init_vp_index() can (re-)use the CPU.
 437          */
 438         if (hv_is_perf_channel(channel))
 439                 hv_clear_alloced_cpu(channel->target_cpu);
 440
 441         /*
 442          * Upon suspend, an in-use hv_sock channel is marked as "rescinded" and
 443          * the relid is invalidated; after hibernation, when the user-space app
 444          * destroys the channel, the relid is INVALID_RELID, and in this case
 445          * it's unnecessary and unsafe to release the old relid, since the same
 446          * relid can refer to a completely different channel now.
 447          */
 448         if (channel->offermsg.child_relid != INVALID_RELID)
 449                 vmbus_release_relid(channel->offermsg.child_relid);
 450
 451         free_channel(channel);
 452 }
 453
 454 void vmbus_free_channels(void)
 455 {
 456         struct vmbus_channel *channel, *tmp;
 457
 458         list_for_each_entry_safe(channel, tmp, &vmbus_connection.chn_list,
 459                 listentry) {
 460                 /* hv_process_channel_removal() needs this */
 461                 channel->rescind = true;
 462
 463                 vmbus_device_unregister(channel->device_obj);
 464         }
 465 }
 466
 467 /* Note: the function can run concurrently for primary/sub channels. */
 468 static void vmbus_add_channel_work(struct work_struct *work)
 469 {
 470         struct vmbus_channel *newchannel =
 471                 container_of(work, struct vmbus_channel, add_channel_work);
 472         struct vmbus_channel *primary_channel = newchannel->primary_channel;
 473         unsigned long flags;
 474         int ret;
 475
 476         /*
 477          * This state is used to indicate a successful open
 478          * so that when we do close the channel normally, we
 479          * can cleanup properly.
 480          */
 481         newchannel->state = CHANNEL_OPEN_STATE;
 482
 483         if (primary_channel != NULL) {
 484                 /* newchannel is a sub-channel. */
 485                 struct hv_device *dev = primary_channel->device_obj;
 486
 487                 if (vmbus_add_channel_kobj(dev, newchannel))
 488                         goto err_deq_chan;
 489
 490                 if (primary_channel->sc_creation_callback != NULL)
 491                         primary_channel->sc_creation_callback(newchannel);
 492
 493                 newchannel->probe_done = true;
 494                 return;
 495         }
 496
 497         /*
 498          * Start the process of binding the primary channel to the driver
 499          */
 500         newchannel->device_obj = vmbus_device_create(
 501                 &newchannel->offermsg.offer.if_type,
 502                 &newchannel->offermsg.offer.if_instance,
 503                 newchannel);
 504         if (!newchannel->device_obj)
 505                 goto err_deq_chan;
 506
 507         newchannel->device_obj->device_id = newchannel->device_id;
 508         /*
 509          * Add the new device to the bus. This will kick off device-driver
 510          * binding which eventually invokes the device driver's AddDevice()
 511          * method.
 512          */
 513         ret = vmbus_device_register(newchannel->device_obj);
 514
 515         if (ret != 0) {
 516                 pr_err("unable to add child device object (relid %d)\n",
 517                         newchannel->offermsg.child_relid);
 518                 kfree(newchannel->device_obj);
 519                 goto err_deq_chan;
 520         }
 521
 522         newchannel->probe_done = true;
 523         return;
 524
 525 err_deq_chan:
 526         mutex_lock(&vmbus_connection.channel_mutex);
 527
 528         /*
 529          * We need to set the flag, otherwise
 530          * vmbus_onoffer_rescind() can be blocked.
 531          */
 532         newchannel->probe_done = true;
 533
 534         if (primary_channel == NULL) {
 535                 list_del(&newchannel->listentry);
 536         } else {
 537                 spin_lock_irqsave(&primary_channel->lock, flags);
 538                 list_del(&newchannel->sc_list);
 539                 spin_unlock_irqrestore(&primary_channel->lock, flags);
 540         }
 541
 542         /* vmbus_process_offer() has mapped the channel. */
 543         vmbus_channel_unmap_relid(newchannel);
 544
 545         mutex_unlock(&vmbus_connection.channel_mutex);
 546
 547         vmbus_release_relid(newchannel->offermsg.child_relid);
 548
 549         free_channel(newchannel);
 550 }
 551
 552 /*
 553  * vmbus_process_offer - Process the offer by creating a channel/device
 554  * associated with this offer
 555  */
 556 static void vmbus_process_offer(struct vmbus_channel *newchannel)
 557 {
 558         struct vmbus_channel *channel;
 559         struct workqueue_struct *wq;
 560         unsigned long flags;
 561         bool fnew = true;
 562
 563         /*
 564          * Synchronize vmbus_process_offer() and CPU hotplugging:
 565          *
 566          * CPU1                         CPU2
 567          *
 568          * [vmbus_process_offer()]      [Hot removal of the CPU]
 569          *
 570          * CPU_READ_LOCK                CPUS_WRITE_LOCK
 571          * LOAD cpu_online_mask         SEARCH chn_list
 572          * STORE target_cpu             LOAD target_cpu
 573          * INSERT chn_list              STORE cpu_online_mask
 574          * CPUS_READ_UNLOCK             CPUS_WRITE_UNLOCK
 575          *
 576          * Forbids: CPU1's LOAD from *not* seing CPU2's STORE &&
 577          *              CPU2's SEARCH from *not* seeing CPU1's INSERT
 578          *
 579          * Forbids: CPU2's SEARCH from seeing CPU1's INSERT &&
 580          *              CPU2's LOAD from *not* seing CPU1's STORE
 581          */
 582         cpus_read_lock();
 583
 584         /*
 585          * Serializes the modifications of the chn_list list as well as
 586          * the accesses to next_numa_node_id in init_vp_index().
 587          */
 588         mutex_lock(&vmbus_connection.channel_mutex);
 589
 590         init_vp_index(newchannel);
 591
 592         /* Remember the channels that should be cleaned up upon suspend. */
 593         if (is_hvsock_channel(newchannel) || is_sub_channel(newchannel))
 594                 atomic_inc(&vmbus_connection.nr_chan_close_on_suspend);
 595
 596         /*
 597          * Now that we have acquired the channel_mutex,
 598          * we can release the potentially racing rescind thread.
 599          */
 600         atomic_dec(&vmbus_connection.offer_in_progress);
 601
 602         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 603                 if (guid_equal(&channel->offermsg.offer.if_type,
 604                                &newchannel->offermsg.offer.if_type) &&
 605                     guid_equal(&channel->offermsg.offer.if_instance,
 606                                &newchannel->offermsg.offer.if_instance)) {
 607                         fnew = false;
 608                         break;
 609                 }
 610         }
 611
 612         if (fnew)
 613                 list_add_tail(&newchannel->listentry,
 614                               &vmbus_connection.chn_list);
 615         else {
 616                 /*
 617                  * Check to see if this is a valid sub-channel.
 618                  */
 619                 if (newchannel->offermsg.offer.sub_channel_index == 0) {
 620                         mutex_unlock(&vmbus_connection.channel_mutex);
 621                         /*
 622                          * Don't call free_channel(), because newchannel->kobj
 623                          * is not initialized yet.
 624                          */
 625                         kfree(newchannel);
 626                         WARN_ON_ONCE(1);
 627                         return;
 628                 }
 629                 /*
 630                  * Process the sub-channel.
 631                  */
 632                 newchannel->primary_channel = channel;
 633                 spin_lock_irqsave(&channel->lock, flags);
 634                 list_add_tail(&newchannel->sc_list, &channel->sc_list);
 635                 spin_unlock_irqrestore(&channel->lock, flags);
 636         }
 637
 638         vmbus_channel_map_relid(newchannel);
 639
 640         mutex_unlock(&vmbus_connection.channel_mutex);
 641         cpus_read_unlock();
 642
 643         /*
 644          * vmbus_process_offer() mustn't call channel->sc_creation_callback()
 645          * directly for sub-channels, because sc_creation_callback() ->
 646          * vmbus_open() may never get the host's response to the
 647          * OPEN_CHANNEL message (the host may rescind a channel at any time,
 648          * e.g. in the case of hot removing a NIC), and vmbus_onoffer_rescind()
 649          * may not wake up the vmbus_open() as it's blocked due to a non-zero
 650          * vmbus_connection.offer_in_progress, and finally we have a deadlock.
 651          *
 652          * The above is also true for primary channels, if the related device
 653          * drivers use sync probing mode by default.
 654          *
 655          * And, usually the handling of primary channels and sub-channels can
 656          * depend on each other, so we should offload them to different
 657          * workqueues to avoid possible deadlock, e.g. in sync-probing mode,
 658          * NIC1's netvsc_subchan_work() can race with NIC2's netvsc_probe() ->
 659          * rtnl_lock(), and causes deadlock: the former gets the rtnl_lock
 660          * and waits for all the sub-channels to appear, but the latter
 661          * can't get the rtnl_lock and this blocks the handling of
 662          * sub-channels.
 663          */
 664         INIT_WORK(&newchannel->add_channel_work, vmbus_add_channel_work);
 665         wq = fnew ? vmbus_connection.handle_primary_chan_wq :
 666                     vmbus_connection.handle_sub_chan_wq;
 667         queue_work(wq, &newchannel->add_channel_work);
 668 }
 669
 670 /*
 671  * We use this state to statically distribute the channel interrupt load.
 672  */
 673 static int next_numa_node_id;
 674
 675 /*
 676  * Starting with Win8, we can statically distribute the incoming
 677  * channel interrupt load by binding a channel to VCPU.
 678  *
 679  * For pre-win8 hosts or non-performance critical channels we assign the
 680  * VMBUS_CONNECT_CPU.
 681  *
 682  * Starting with win8, performance critical channels will be distributed
 683  * evenly among all the available NUMA nodes.  Once the node is assigned,
 684  * we will assign the CPU based on a simple round robin scheme.
 685  */
 686 static void init_vp_index(struct vmbus_channel *channel)
 687 {
 688         bool perf_chn = hv_is_perf_channel(channel);
 689         cpumask_var_t available_mask;
 690         struct cpumask *alloced_mask;
 691         u32 target_cpu;
 692         int numa_node;
 693
 694         if ((vmbus_proto_version == VERSION_WS2008) ||
 695             (vmbus_proto_version == VERSION_WIN7) || (!perf_chn) ||
 696             !alloc_cpumask_var(&available_mask, GFP_KERNEL)) {
 697                 /*
 698                  * Prior to win8, all channel interrupts are
 699                  * delivered on VMBUS_CONNECT_CPU.
 700                  * Also if the channel is not a performance critical
 701                  * channel, bind it to VMBUS_CONNECT_CPU.
 702                  * In case alloc_cpumask_var() fails, bind it to
 703                  * VMBUS_CONNECT_CPU.
 704                  */
 705                 channel->numa_node = cpu_to_node(VMBUS_CONNECT_CPU);
 706                 channel->target_cpu = VMBUS_CONNECT_CPU;
 707                 channel->target_vp =
 708                         hv_cpu_number_to_vp_number(VMBUS_CONNECT_CPU);
 709                 if (perf_chn)
 710                         hv_set_alloced_cpu(VMBUS_CONNECT_CPU);
 711                 return;
 712         }
 713
 714         while (true) {
 715                 numa_node = next_numa_node_id++;
 716                 if (numa_node == nr_node_ids) {
 717                         next_numa_node_id = 0;
 718                         continue;
 719                 }
 720                 if (cpumask_empty(cpumask_of_node(numa_node)))
 721                         continue;
 722                 break;
 723         }
 724         channel->numa_node = numa_node;
 725         alloced_mask = &hv_context.hv_numa_map[numa_node];
 726
 727         if (cpumask_weight(alloced_mask) ==
 728             cpumask_weight(cpumask_of_node(numa_node))) {
 729                 /*
 730                  * We have cycled through all the CPUs in the node;
 731                  * reset the alloced map.
 732                  */
 733                 cpumask_clear(alloced_mask);
 734         }
 735
 736         cpumask_xor(available_mask, alloced_mask, cpumask_of_node(numa_node));
 737
 738         target_cpu = cpumask_first(available_mask);
 739         cpumask_set_cpu(target_cpu, alloced_mask);
 740
 741         channel->target_cpu = target_cpu;
 742         channel->target_vp = hv_cpu_number_to_vp_number(target_cpu);
 743
 744         free_cpumask_var(available_mask);
 745 }
 746
 747 static void vmbus_wait_for_unload(void)
 748 {
 749         int cpu;
 750         void *page_addr;
 751         struct hv_message *msg;
 752         struct vmbus_channel_message_header *hdr;
 753         u32 message_type, i;
 754
 755         /*
 756          * CHANNELMSG_UNLOAD_RESPONSE is always delivered to the CPU which was
 757          * used for initial contact or to CPU0 depending on host version. When
 758          * we're crashing on a different CPU let's hope that IRQ handler on
 759          * the cpu which receives CHANNELMSG_UNLOAD_RESPONSE is still
 760          * functional and vmbus_unload_response() will complete
 761          * vmbus_connection.unload_event. If not, the last thing we can do is
 762          * read message pages for all CPUs directly.
 763          *
 764          * Wait no more than 10 seconds so that the panic path can't get
 765          * hung forever in case the response message isn't seen.
 766          */
 767         for (i = 0; i < 1000; i++) {
 768                 if (completion_done(&vmbus_connection.unload_event))
 769                         break;
 770
 771                 for_each_online_cpu(cpu) {
 772                         struct hv_per_cpu_context *hv_cpu
 773                                 = per_cpu_ptr(hv_context.cpu_context, cpu);
 774
 775                         page_addr = hv_cpu->synic_message_page;
 776                         msg = (struct hv_message *)page_addr
 777                                 + VMBUS_MESSAGE_SINT;
 778
 779                         message_type = READ_ONCE(msg->header.message_type);
 780                         if (message_type == HVMSG_NONE)
 781                                 continue;
 782
 783                         hdr = (struct vmbus_channel_message_header *)
 784                                 msg->u.payload;
 785
 786                         if (hdr->msgtype == CHANNELMSG_UNLOAD_RESPONSE)
 787                                 complete(&vmbus_connection.unload_event);
 788
 789                         vmbus_signal_eom(msg, message_type);
 790                 }
 791
 792                 mdelay(10);
 793         }
 794
 795         /*
 796          * We're crashing and already got the UNLOAD_RESPONSE, cleanup all
 797          * maybe-pending messages on all CPUs to be able to receive new
 798          * messages after we reconnect.
 799          */
 800         for_each_online_cpu(cpu) {
 801                 struct hv_per_cpu_context *hv_cpu
 802                         = per_cpu_ptr(hv_context.cpu_context, cpu);
 803
 804                 page_addr = hv_cpu->synic_message_page;
 805                 msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
 806                 msg->header.message_type = HVMSG_NONE;
 807         }
 808 }
 809
 810 /*
 811  * vmbus_unload_response - Handler for the unload response.
 812  */
 813 static void vmbus_unload_response(struct vmbus_channel_message_header *hdr)
 814 {
 815         /*
 816          * This is a global event; just wakeup the waiting thread.
 817          * Once we successfully unload, we can cleanup the monitor state.
 818          */
 819         complete(&vmbus_connection.unload_event);
 820 }
 821
 822 void vmbus_initiate_unload(bool crash)
 823 {
 824         struct vmbus_channel_message_header hdr;
 825
 826         if (xchg(&vmbus_connection.conn_state, DISCONNECTED) == DISCONNECTED)
 827                 return;
 828
 829         /* Pre-Win2012R2 hosts don't support reconnect */
 830         if (vmbus_proto_version < VERSION_WIN8_1)
 831                 return;
 832
 833         init_completion(&vmbus_connection.unload_event);
 834         memset(&hdr, 0, sizeof(struct vmbus_channel_message_header));
 835         hdr.msgtype = CHANNELMSG_UNLOAD;
 836         vmbus_post_msg(&hdr, sizeof(struct vmbus_channel_message_header),
 837                        !crash);
 838
 839         /*
 840          * vmbus_initiate_unload() is also called on crash and the crash can be
 841          * happening in an interrupt context, where scheduling is impossible.
 842          */
 843         if (!crash)
 844                 wait_for_completion(&vmbus_connection.unload_event);
 845         else
 846                 vmbus_wait_for_unload();
 847 }
 848
 849 static void check_ready_for_resume_event(void)
 850 {
 851         /*
 852          * If all the old primary channels have been fixed up, then it's safe
 853          * to resume.
 854          */
 855         if (atomic_dec_and_test(&vmbus_connection.nr_chan_fixup_on_resume))
 856                 complete(&vmbus_connection.ready_for_resume_event);
 857 }
 858
 859 static void vmbus_setup_channel_state(struct vmbus_channel *channel,
 860                                       struct vmbus_channel_offer_channel *offer)
 861 {
 862         /*
 863          * Setup state for signalling the host.
 864          */
 865         channel->sig_event = VMBUS_EVENT_CONNECTION_ID;
 866
 867         if (vmbus_proto_version != VERSION_WS2008) {
 868                 channel->is_dedicated_interrupt =
 869                                 (offer->is_dedicated_interrupt != 0);
 870                 channel->sig_event = offer->connection_id;
 871         }
 872
 873         memcpy(&channel->offermsg, offer,
 874                sizeof(struct vmbus_channel_offer_channel));
 875         channel->monitor_grp = (u8)offer->monitorid / 32;
 876         channel->monitor_bit = (u8)offer->monitorid % 32;
 877         channel->device_id = hv_get_dev_type(channel);
 878 }
 879
 880 /*
 881  * find_primary_channel_by_offer - Get the channel object given the new offer.
 882  * This is only used in the resume path of hibernation.
 883  */
 884 static struct vmbus_channel *
 885 find_primary_channel_by_offer(const struct vmbus_channel_offer_channel *offer)
 886 {
 887         struct vmbus_channel *channel = NULL, *iter;
 888         const guid_t *inst1, *inst2;
 889
 890         /* Ignore sub-channel offers. */
 891         if (offer->offer.sub_channel_index != 0)
 892                 return NULL;
 893
 894         mutex_lock(&vmbus_connection.channel_mutex);
 895
 896         list_for_each_entry(iter, &vmbus_connection.chn_list, listentry) {
 897                 inst1 = &iter->offermsg.offer.if_instance;
 898                 inst2 = &offer->offer.if_instance;
 899
 900                 if (guid_equal(inst1, inst2)) {
 901                         channel = iter;
 902                         break;
 903                 }
 904         }
 905
 906         mutex_unlock(&vmbus_connection.channel_mutex);
 907
 908         return channel;
 909 }
 910
 911 /*
 912  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 913  *
 914  */
 915 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 916 {
 917         struct vmbus_channel_offer_channel *offer;
 918         struct vmbus_channel *oldchannel, *newchannel;
 919         size_t offer_sz;
 920
 921         offer = (struct vmbus_channel_offer_channel *)hdr;
 922
 923         trace_vmbus_onoffer(offer);
 924
 925         oldchannel = find_primary_channel_by_offer(offer);
 926
 927         if (oldchannel != NULL) {
 928                 /*
 929                  * We're resuming from hibernation: all the sub-channel and
 930                  * hv_sock channels we had before the hibernation should have
 931                  * been cleaned up, and now we must be seeing a re-offered
 932                  * primary channel that we had before the hibernation.
 933                  */
 934
 935                 /*
 936                  * { Initially: channel relid = INVALID_RELID,
 937                  *              channels[valid_relid] = NULL }
 938                  *
 939                  * CPU1                                 CPU2
 940                  *
 941                  * [vmbus_onoffer()]                    [vmbus_device_release()]
 942                  *
 943                  * LOCK channel_mutex                   LOCK channel_mutex
 944                  * STORE channel relid = valid_relid    LOAD r1 = channel relid
 945                  * MAP_RELID channel                    if (r1 != INVALID_RELID)
 946                  * UNLOCK channel_mutex                   UNMAP_RELID channel
 947                  *                                      UNLOCK channel_mutex
 948                  *
 949                  * Forbids: r1 == valid_relid &&
 950                  *              channels[valid_relid] == channel
 951                  *
 952                  * Note.  r1 can be INVALID_RELID only for an hv_sock channel.
 953                  * None of the hv_sock channels which were present before the
 954                  * suspend are re-offered upon the resume.  See the WARN_ON()
 955                  * in hv_process_channel_removal().
 956                  */
 957                 mutex_lock(&vmbus_connection.channel_mutex);
 958
 959                 atomic_dec(&vmbus_connection.offer_in_progress);
 960
 961                 WARN_ON(oldchannel->offermsg.child_relid != INVALID_RELID);
 962                 /* Fix up the relid. */
 963                 oldchannel->offermsg.child_relid = offer->child_relid;
 964
 965                 offer_sz = sizeof(*offer);
 966                 if (memcmp(offer, &oldchannel->offermsg, offer_sz) != 0) {
 967                         /*
 968                          * This is not an error, since the host can also change
 969                          * the other field(s) of the offer, e.g. on WS RS5
 970                          * (Build 17763), the offer->connection_id of the
 971                          * Mellanox VF vmbus device can change when the host
 972                          * reoffers the device upon resume.
 973                          */
 974                         pr_debug("vmbus offer changed: relid=%d\n",
 975                                  offer->child_relid);
 976
 977                         print_hex_dump_debug("Old vmbus offer: ",
 978                                              DUMP_PREFIX_OFFSET, 16, 4,
 979                                              &oldchannel->offermsg, offer_sz,
 980                                              false);
 981                         print_hex_dump_debug("New vmbus offer: ",
 982                                              DUMP_PREFIX_OFFSET, 16, 4,
 983                                              offer, offer_sz, false);
 984
 985                         /* Fix up the old channel. */
 986                         vmbus_setup_channel_state(oldchannel, offer);
 987                 }
 988
 989                 /* Add the channel back to the array of channels. */
 990                 vmbus_channel_map_relid(oldchannel);
 991                 check_ready_for_resume_event();
 992
 993                 mutex_unlock(&vmbus_connection.channel_mutex);
 994                 return;
 995         }
 996
 997         /* Allocate the channel object and save this offer. */
 998         newchannel = alloc_channel();
 999         if (!newchannel) {
1000                 vmbus_release_relid(offer->child_relid);
1001                 atomic_dec(&vmbus_connection.offer_in_progress);
1002                 pr_err("Unable to allocate channel object\n");
1003                 return;
1004         }
1005
1006         vmbus_setup_channel_state(newchannel, offer);
1007
1008         vmbus_process_offer(newchannel);
1009 }
1010
1011 static void check_ready_for_suspend_event(void)
1012 {
1013         /*
1014          * If all the sub-channels or hv_sock channels have been cleaned up,
1015          * then it's safe to suspend.
1016          */
1017         if (atomic_dec_and_test(&vmbus_connection.nr_chan_close_on_suspend))
1018                 complete(&vmbus_connection.ready_for_suspend_event);
1019 }
1020
1021 /*
1022  * vmbus_onoffer_rescind - Rescind offer handler.
1023  *
1024  * We queue a work item to process this offer synchronously
1025  */
1026 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
1027 {
1028         struct vmbus_channel_rescind_offer *rescind;
1029         struct vmbus_channel *channel;
1030         struct device *dev;
1031         bool clean_up_chan_for_suspend;
1032
1033         rescind = (struct vmbus_channel_rescind_offer *)hdr;
1034
1035         trace_vmbus_onoffer_rescind(rescind);
1036
1037         /*
1038          * The offer msg and the corresponding rescind msg
1039          * from the host are guranteed to be ordered -
1040          * offer comes in first and then the rescind.
1041          * Since we process these events in work elements,
1042          * and with preemption, we may end up processing
1043          * the events out of order.  We rely on the synchronization
1044          * provided by offer_in_progress and by channel_mutex for
1045          * ordering these events:
1046          *
1047          * { Initially: offer_in_progress = 1 }
1048          *
1049          * CPU1                         CPU2
1050          *
1051          * [vmbus_onoffer()]            [vmbus_onoffer_rescind()]
1052          *
1053          * LOCK channel_mutex           WAIT_ON offer_in_progress == 0
1054          * DECREMENT offer_in_progress  LOCK channel_mutex
1055          * STORE channels[]             LOAD channels[]
1056          * UNLOCK channel_mutex         UNLOCK channel_mutex
1057          *
1058          * Forbids: CPU2's LOAD from *not* seeing CPU1's STORE
1059          */
1060
1061         while (atomic_read(&vmbus_connection.offer_in_progress) != 0) {
1062                 /*
1063                  * We wait here until any channel offer is currently
1064                  * being processed.
1065                  */
1066                 msleep(1);
1067         }
1068
1069         mutex_lock(&vmbus_connection.channel_mutex);
1070         channel = relid2channel(rescind->child_relid);
1071         mutex_unlock(&vmbus_connection.channel_mutex);
1072
1073         if (channel == NULL) {
1074                 /*
1075                  * We failed in processing the offer message;
1076                  * we would have cleaned up the relid in that
1077                  * failure path.
1078                  */
1079                 return;
1080         }
1081
1082         clean_up_chan_for_suspend = is_hvsock_channel(channel) ||
1083                                     is_sub_channel(channel);
1084         /*
1085          * Before setting channel->rescind in vmbus_rescind_cleanup(), we
1086          * should make sure the channel callback is not running any more.
1087          */
1088         vmbus_reset_channel_cb(channel);
1089
1090         /*
1091          * Now wait for offer handling to complete.
1092          */
1093         vmbus_rescind_cleanup(channel);
1094         while (READ_ONCE(channel->probe_done) == false) {
1095                 /*
1096                  * We wait here until any channel offer is currently
1097                  * being processed.
1098                  */
1099                 msleep(1);
1100         }
1101
1102         /*
1103          * At this point, the rescind handling can proceed safely.
1104          */
1105
1106         if (channel->device_obj) {
1107                 if (channel->chn_rescind_callback) {
1108                         channel->chn_rescind_callback(channel);
1109
1110                         if (clean_up_chan_for_suspend)
1111                                 check_ready_for_suspend_event();
1112
1113                         return;
1114                 }
1115                 /*
1116                  * We will have to unregister this device from the
1117                  * driver core.
1118                  */
1119                 dev = get_device(&channel->device_obj->device);
1120                 if (dev) {
1121                         vmbus_device_unregister(channel->device_obj);
1122                         put_device(dev);
1123                 }
1124         }
1125         if (channel->primary_channel != NULL) {
1126                 /*
1127                  * Sub-channel is being rescinded. Following is the channel
1128                  * close sequence when initiated from the driveri (refer to
1129                  * vmbus_close() for details):
1130                  * 1. Close all sub-channels first
1131                  * 2. Then close the primary channel.
1132                  */
1133                 mutex_lock(&vmbus_connection.channel_mutex);
1134                 if (channel->state == CHANNEL_OPEN_STATE) {
1135                         /*
1136                          * The channel is currently not open;
1137                          * it is safe for us to cleanup the channel.
1138                          */
1139                         hv_process_channel_removal(channel);
1140                 } else {
1141                         complete(&channel->rescind_event);
1142                 }
1143                 mutex_unlock(&vmbus_connection.channel_mutex);
1144         }
1145
1146         /* The "channel" may have been freed. Do not access it any longer. */
1147
1148         if (clean_up_chan_for_suspend)
1149                 check_ready_for_suspend_event();
1150 }
1151
1152 void vmbus_hvsock_device_unregister(struct vmbus_channel *channel)
1153 {
1154         BUG_ON(!is_hvsock_channel(channel));
1155
1156         /* We always get a rescind msg when a connection is closed. */
1157         while (!READ_ONCE(channel->probe_done) || !READ_ONCE(channel->rescind))
1158                 msleep(1);
1159
1160         vmbus_device_unregister(channel->device_obj);
1161 }
1162 EXPORT_SYMBOL_GPL(vmbus_hvsock_device_unregister);
1163
1164
1165 /*
1166  * vmbus_onoffers_delivered -
1167  * This is invoked when all offers have been delivered.
1168  *
1169  * Nothing to do here.
1170  */
1171 static void vmbus_onoffers_delivered(
1172                         struct vmbus_channel_message_header *hdr)
1173 {
1174 }
1175
1176 /*
1177  * vmbus_onopen_result - Open result handler.
1178  *
1179  * This is invoked when we received a response to our channel open request.
1180  * Find the matching request, copy the response and signal the requesting
1181  * thread.
1182  */
1183 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
1184 {
1185         struct vmbus_channel_open_result *result;
1186         struct vmbus_channel_msginfo *msginfo;
1187         struct vmbus_channel_message_header *requestheader;
1188         struct vmbus_channel_open_channel *openmsg;
1189         unsigned long flags;
1190
1191         result = (struct vmbus_channel_open_result *)hdr;
1192
1193         trace_vmbus_onopen_result(result);
1194
1195         /*
1196          * Find the open msg, copy the result and signal/unblock the wait event
1197          */
1198         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1199
1200         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1201                                 msglistentry) {
1202                 requestheader =
1203                         (struct vmbus_channel_message_header *)msginfo->msg;
1204
1205                 if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
1206                         openmsg =
1207                         (struct vmbus_channel_open_channel *)msginfo->msg;
1208                         if (openmsg->child_relid == result->child_relid &&
1209                             openmsg->openid == result->openid) {
1210                                 memcpy(&msginfo->response.open_result,
1211                                        result,
1212                                        sizeof(
1213                                         struct vmbus_channel_open_result));
1214                                 complete(&msginfo->waitevent);
1215                                 break;
1216                         }
1217                 }
1218         }
1219         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1220 }
1221
1222 /*
1223  * vmbus_ongpadl_created - GPADL created handler.
1224  *
1225  * This is invoked when we received a response to our gpadl create request.
1226  * Find the matching request, copy the response and signal the requesting
1227  * thread.
1228  */
1229 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
1230 {
1231         struct vmbus_channel_gpadl_created *gpadlcreated;
1232         struct vmbus_channel_msginfo *msginfo;
1233         struct vmbus_channel_message_header *requestheader;
1234         struct vmbus_channel_gpadl_header *gpadlheader;
1235         unsigned long flags;
1236
1237         gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
1238
1239         trace_vmbus_ongpadl_created(gpadlcreated);
1240
1241         /*
1242          * Find the establish msg, copy the result and signal/unblock the wait
1243          * event
1244          */
1245         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1246
1247         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1248                                 msglistentry) {
1249                 requestheader =
1250                         (struct vmbus_channel_message_header *)msginfo->msg;
1251
1252                 if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
1253                         gpadlheader =
1254                         (struct vmbus_channel_gpadl_header *)requestheader;
1255
1256                         if ((gpadlcreated->child_relid ==
1257                              gpadlheader->child_relid) &&
1258                             (gpadlcreated->gpadl == gpadlheader->gpadl)) {
1259                                 memcpy(&msginfo->response.gpadl_created,
1260                                        gpadlcreated,
1261                                        sizeof(
1262                                         struct vmbus_channel_gpadl_created));
1263                                 complete(&msginfo->waitevent);
1264                                 break;
1265                         }
1266                 }
1267         }
1268         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1269 }
1270
1271 /*
1272  * vmbus_ongpadl_torndown - GPADL torndown handler.
1273  *
1274  * This is invoked when we received a response to our gpadl teardown request.
1275  * Find the matching request, copy the response and signal the requesting
1276  * thread.
1277  */
1278 static void vmbus_ongpadl_torndown(
1279                         struct vmbus_channel_message_header *hdr)
1280 {
1281         struct vmbus_channel_gpadl_torndown *gpadl_torndown;
1282         struct vmbus_channel_msginfo *msginfo;
1283         struct vmbus_channel_message_header *requestheader;
1284         struct vmbus_channel_gpadl_teardown *gpadl_teardown;
1285         unsigned long flags;
1286
1287         gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
1288
1289         trace_vmbus_ongpadl_torndown(gpadl_torndown);
1290
1291         /*
1292          * Find the open msg, copy the result and signal/unblock the wait event
1293          */
1294         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1295
1296         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1297                                 msglistentry) {
1298                 requestheader =
1299                         (struct vmbus_channel_message_header *)msginfo->msg;
1300
1301                 if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
1302                         gpadl_teardown =
1303                         (struct vmbus_channel_gpadl_teardown *)requestheader;
1304
1305                         if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
1306                                 memcpy(&msginfo->response.gpadl_torndown,
1307                                        gpadl_torndown,
1308                                        sizeof(
1309                                         struct vmbus_channel_gpadl_torndown));
1310                                 complete(&msginfo->waitevent);
1311                                 break;
1312                         }
1313                 }
1314         }
1315         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1316 }
1317
1318 /*
1319  * vmbus_onversion_response - Version response handler
1320  *
1321  * This is invoked when we received a response to our initiate contact request.
1322  * Find the matching request, copy the response and signal the requesting
1323  * thread.
1324  */
1325 static void vmbus_onversion_response(
1326                 struct vmbus_channel_message_header *hdr)
1327 {
1328         struct vmbus_channel_msginfo *msginfo;
1329         struct vmbus_channel_message_header *requestheader;
1330         struct vmbus_channel_version_response *version_response;
1331         unsigned long flags;
1332
1333         version_response = (struct vmbus_channel_version_response *)hdr;
1334
1335         trace_vmbus_onversion_response(version_response);
1336
1337         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1338
1339         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1340                                 msglistentry) {
1341                 requestheader =
1342                         (struct vmbus_channel_message_header *)msginfo->msg;
1343
1344                 if (requestheader->msgtype ==
1345                     CHANNELMSG_INITIATE_CONTACT) {
1346                         memcpy(&msginfo->response.version_response,
1347                               version_response,
1348                               sizeof(struct vmbus_channel_version_response));
1349                         complete(&msginfo->waitevent);
1350                 }
1351         }
1352         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1353 }
1354
1355 /* Channel message dispatch table */
1356 const struct vmbus_channel_message_table_entry
1357 channel_message_table[CHANNELMSG_COUNT] = {
1358         { CHANNELMSG_INVALID,                   0, NULL, 0},
1359         { CHANNELMSG_OFFERCHANNEL,              0, vmbus_onoffer,
1360                 sizeof(struct vmbus_channel_offer_channel)},
1361         { CHANNELMSG_RESCIND_CHANNELOFFER,      0, vmbus_onoffer_rescind,
1362                 sizeof(struct vmbus_channel_rescind_offer) },
1363         { CHANNELMSG_REQUESTOFFERS,             0, NULL, 0},
1364         { CHANNELMSG_ALLOFFERS_DELIVERED,       1, vmbus_onoffers_delivered, 0},
1365         { CHANNELMSG_OPENCHANNEL,               0, NULL, 0},
1366         { CHANNELMSG_OPENCHANNEL_RESULT,        1, vmbus_onopen_result,
1367                 sizeof(struct vmbus_channel_open_result)},
1368         { CHANNELMSG_CLOSECHANNEL,              0, NULL, 0},
1369         { CHANNELMSG_GPADL_HEADER,              0, NULL, 0},
1370         { CHANNELMSG_GPADL_BODY,                0, NULL, 0},
1371         { CHANNELMSG_GPADL_CREATED,             1, vmbus_ongpadl_created,
1372                 sizeof(struct vmbus_channel_gpadl_created)},
1373         { CHANNELMSG_GPADL_TEARDOWN,            0, NULL, 0},
1374         { CHANNELMSG_GPADL_TORNDOWN,            1, vmbus_ongpadl_torndown,
1375                 sizeof(struct vmbus_channel_gpadl_torndown) },
1376         { CHANNELMSG_RELID_RELEASED,            0, NULL, 0},
1377         { CHANNELMSG_INITIATE_CONTACT,          0, NULL, 0},
1378         { CHANNELMSG_VERSION_RESPONSE,          1, vmbus_onversion_response,
1379                 sizeof(struct vmbus_channel_version_response)},
1380         { CHANNELMSG_UNLOAD,                    0, NULL, 0},
1381         { CHANNELMSG_UNLOAD_RESPONSE,           1, vmbus_unload_response, 0},
1382         { CHANNELMSG_18,                        0, NULL, 0},
1383         { CHANNELMSG_19,                        0, NULL, 0},
1384         { CHANNELMSG_20,                        0, NULL, 0},
1385         { CHANNELMSG_TL_CONNECT_REQUEST,        0, NULL, 0},
1386         { CHANNELMSG_MODIFYCHANNEL,             0, NULL, 0},
1387         { CHANNELMSG_TL_CONNECT_RESULT,         0, NULL, 0},
1388 };
1389
1390 /*
1391  * vmbus_onmessage - Handler for channel protocol messages.
1392  *
1393  * This is invoked in the vmbus worker thread context.
1394  */
1395 void vmbus_onmessage(struct vmbus_channel_message_header *hdr)
1396 {
1397         trace_vmbus_on_message(hdr);
1398
1399         /*
1400          * vmbus_on_msg_dpc() makes sure the hdr->msgtype here can not go
1401          * out of bound and the message_handler pointer can not be NULL.
1402          */
1403         channel_message_table[hdr->msgtype].message_handler(hdr);
1404 }
1405
1406 /*
1407  * vmbus_request_offers - Send a request to get all our pending offers.
1408  */
1409 int vmbus_request_offers(void)
1410 {
1411         struct vmbus_channel_message_header *msg;
1412         struct vmbus_channel_msginfo *msginfo;
1413         int ret;
1414
1415         msginfo = kmalloc(sizeof(*msginfo) +
1416                           sizeof(struct vmbus_channel_message_header),
1417                           GFP_KERNEL);
1418         if (!msginfo)
1419                 return -ENOMEM;
1420
1421         msg = (struct vmbus_channel_message_header *)msginfo->msg;
1422
1423         msg->msgtype = CHANNELMSG_REQUESTOFFERS;
1424
1425         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_message_header),
1426                              true);
1427
1428         trace_vmbus_request_offers(ret);
1429
1430         if (ret != 0) {
1431                 pr_err("Unable to request offers - %d\n", ret);
1432
1433                 goto cleanup;
1434         }
1435
1436 cleanup:
1437         kfree(msginfo);
1438
1439         return ret;
1440 }
1441
1442 static void invoke_sc_cb(struct vmbus_channel *primary_channel)
1443 {
1444         struct list_head *cur, *tmp;
1445         struct vmbus_channel *cur_channel;
1446
1447         if (primary_channel->sc_creation_callback == NULL)
1448                 return;
1449
1450         list_for_each_safe(cur, tmp, &primary_channel->sc_list) {
1451                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
1452
1453                 primary_channel->sc_creation_callback(cur_channel);
1454         }
1455 }
1456
1457 void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
1458                                 void (*sc_cr_cb)(struct vmbus_channel *new_sc))
1459 {
1460         primary_channel->sc_creation_callback = sc_cr_cb;
1461 }
1462 EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
1463
1464 bool vmbus_are_subchannels_present(struct vmbus_channel *primary)
1465 {
1466         bool ret;
1467
1468         ret = !list_empty(&primary->sc_list);
1469
1470         if (ret) {
1471                 /*
1472                  * Invoke the callback on sub-channel creation.
1473                  * This will present a uniform interface to the
1474                  * clients.
1475                  */
1476                 invoke_sc_cb(primary);
1477         }
1478
1479         return ret;
1480 }
1481 EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present);
1482
1483 void vmbus_set_chn_rescind_callback(struct vmbus_channel *channel,
1484                 void (*chn_rescind_cb)(struct vmbus_channel *))
1485 {
1486         channel->chn_rescind_callback = chn_rescind_cb;
1487 }
1488 EXPORT_SYMBOL_GPL(vmbus_set_chn_rescind_callback);