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           .allowed_in_isolated = false,
  35         },
  36
  37         /* SCSI */
  38         { .dev_type = HV_SCSI,
  39           HV_SCSI_GUID,
  40           .perf_device = true,
  41           .allowed_in_isolated = true,
  42         },
  43
  44         /* Fibre Channel */
  45         { .dev_type = HV_FC,
  46           HV_SYNTHFC_GUID,
  47           .perf_device = true,
  48           .allowed_in_isolated = false,
  49         },
  50
  51         /* Synthetic NIC */
  52         { .dev_type = HV_NIC,
  53           HV_NIC_GUID,
  54           .perf_device = true,
  55           .allowed_in_isolated = true,
  56         },
  57
  58         /* Network Direct */
  59         { .dev_type = HV_ND,
  60           HV_ND_GUID,
  61           .perf_device = true,
  62           .allowed_in_isolated = false,
  63         },
  64
  65         /* PCIE */
  66         { .dev_type = HV_PCIE,
  67           HV_PCIE_GUID,
  68           .perf_device = false,
  69           .allowed_in_isolated = false,
  70         },
  71
  72         /* Synthetic Frame Buffer */
  73         { .dev_type = HV_FB,
  74           HV_SYNTHVID_GUID,
  75           .perf_device = false,
  76           .allowed_in_isolated = false,
  77         },
  78
  79         /* Synthetic Keyboard */
  80         { .dev_type = HV_KBD,
  81           HV_KBD_GUID,
  82           .perf_device = false,
  83           .allowed_in_isolated = false,
  84         },
  85
  86         /* Synthetic MOUSE */
  87         { .dev_type = HV_MOUSE,
  88           HV_MOUSE_GUID,
  89           .perf_device = false,
  90           .allowed_in_isolated = false,
  91         },
  92
  93         /* KVP */
  94         { .dev_type = HV_KVP,
  95           HV_KVP_GUID,
  96           .perf_device = false,
  97           .allowed_in_isolated = false,
  98         },
  99
 100         /* Time Synch */
 101         { .dev_type = HV_TS,
 102           HV_TS_GUID,
 103           .perf_device = false,
 104           .allowed_in_isolated = true,
 105         },
 106
 107         /* Heartbeat */
 108         { .dev_type = HV_HB,
 109           HV_HEART_BEAT_GUID,
 110           .perf_device = false,
 111           .allowed_in_isolated = true,
 112         },
 113
 114         /* Shutdown */
 115         { .dev_type = HV_SHUTDOWN,
 116           HV_SHUTDOWN_GUID,
 117           .perf_device = false,
 118           .allowed_in_isolated = true,
 119         },
 120
 121         /* File copy */
 122         { .dev_type = HV_FCOPY,
 123           HV_FCOPY_GUID,
 124           .perf_device = false,
 125           .allowed_in_isolated = false,
 126         },
 127
 128         /* Backup */
 129         { .dev_type = HV_BACKUP,
 130           HV_VSS_GUID,
 131           .perf_device = false,
 132           .allowed_in_isolated = false,
 133         },
 134
 135         /* Dynamic Memory */
 136         { .dev_type = HV_DM,
 137           HV_DM_GUID,
 138           .perf_device = false,
 139           .allowed_in_isolated = false,
 140         },
 141
 142         /* Unknown GUID */
 143         { .dev_type = HV_UNKNOWN,
 144           .perf_device = false,
 145           .allowed_in_isolated = false,
 146         },
 147 };
 148
 149 static const struct {
 150         guid_t guid;
 151 } vmbus_unsupported_devs[] = {
 152         { HV_AVMA1_GUID },
 153         { HV_AVMA2_GUID },
 154         { HV_RDV_GUID   },
 155 };
 156
 157 /*
 158  * The rescinded channel may be blocked waiting for a response from the host;
 159  * take care of that.
 160  */
 161 static void vmbus_rescind_cleanup(struct vmbus_channel *channel)
 162 {
 163         struct vmbus_channel_msginfo *msginfo;
 164         unsigned long flags;
 165
 166
 167         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 168         channel->rescind = true;
 169         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
 170                                 msglistentry) {
 171
 172                 if (msginfo->waiting_channel == channel) {
 173                         complete(&msginfo->waitevent);
 174                         break;
 175                 }
 176         }
 177         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 178 }
 179
 180 static bool is_unsupported_vmbus_devs(const guid_t *guid)
 181 {
 182         int i;
 183
 184         for (i = 0; i < ARRAY_SIZE(vmbus_unsupported_devs); i++)
 185                 if (guid_equal(guid, &vmbus_unsupported_devs[i].guid))
 186                         return true;
 187         return false;
 188 }
 189
 190 static u16 hv_get_dev_type(const struct vmbus_channel *channel)
 191 {
 192         const guid_t *guid = &channel->offermsg.offer.if_type;
 193         u16 i;
 194
 195         if (is_hvsock_channel(channel) || is_unsupported_vmbus_devs(guid))
 196                 return HV_UNKNOWN;
 197
 198         for (i = HV_IDE; i < HV_UNKNOWN; i++) {
 199                 if (guid_equal(guid, &vmbus_devs[i].guid))
 200                         return i;
 201         }
 202         pr_info("Unknown GUID: %pUl\n", guid);
 203         return i;
 204 }
 205
 206 /**
 207  * vmbus_prep_negotiate_resp() - Create default response for Negotiate message
 208  * @icmsghdrp: Pointer to msg header structure
 209  * @buf: Raw buffer channel data
 210  * @buflen: Length of the raw buffer channel data.
 211  * @fw_version: The framework versions we can support.
 212  * @fw_vercnt: The size of @fw_version.
 213  * @srv_version: The service versions we can support.
 214  * @srv_vercnt: The size of @srv_version.
 215  * @nego_fw_version: The selected framework version.
 216  * @nego_srv_version: The selected service version.
 217  *
 218  * Note: Versions are given in decreasing order.
 219  *
 220  * Set up and fill in default negotiate response message.
 221  * Mainly used by Hyper-V drivers.
 222  */
 223 bool vmbus_prep_negotiate_resp(struct icmsg_hdr *icmsghdrp, u8 *buf,
 224                                 u32 buflen, const int *fw_version, int fw_vercnt,
 225                                 const int *srv_version, int srv_vercnt,
 226                                 int *nego_fw_version, int *nego_srv_version)
 227 {
 228         int icframe_major, icframe_minor;
 229         int icmsg_major, icmsg_minor;
 230         int fw_major, fw_minor;
 231         int srv_major, srv_minor;
 232         int i, j;
 233         bool found_match = false;
 234         struct icmsg_negotiate *negop;
 235
 236         /* Check that there's enough space for icframe_vercnt, icmsg_vercnt */
 237         if (buflen < ICMSG_HDR + offsetof(struct icmsg_negotiate, reserved)) {
 238                 pr_err_ratelimited("Invalid icmsg negotiate\n");
 239                 return false;
 240         }
 241
 242         icmsghdrp->icmsgsize = 0x10;
 243         negop = (struct icmsg_negotiate *)&buf[ICMSG_HDR];
 244
 245         icframe_major = negop->icframe_vercnt;
 246         icframe_minor = 0;
 247
 248         icmsg_major = negop->icmsg_vercnt;
 249         icmsg_minor = 0;
 250
 251         /* Validate negop packet */
 252         if (icframe_major > IC_VERSION_NEGOTIATION_MAX_VER_COUNT ||
 253             icmsg_major > IC_VERSION_NEGOTIATION_MAX_VER_COUNT ||
 254             ICMSG_NEGOTIATE_PKT_SIZE(icframe_major, icmsg_major) > buflen) {
 255                 pr_err_ratelimited("Invalid icmsg negotiate - icframe_major: %u, icmsg_major: %u\n",
 256                                    icframe_major, icmsg_major);
 257                 goto fw_error;
 258         }
 259
 260         /*
 261          * Select the framework version number we will
 262          * support.
 263          */
 264
 265         for (i = 0; i < fw_vercnt; i++) {
 266                 fw_major = (fw_version[i] >> 16);
 267                 fw_minor = (fw_version[i] & 0xFFFF);
 268
 269                 for (j = 0; j < negop->icframe_vercnt; j++) {
 270                         if ((negop->icversion_data[j].major == fw_major) &&
 271                             (negop->icversion_data[j].minor == fw_minor)) {
 272                                 icframe_major = negop->icversion_data[j].major;
 273                                 icframe_minor = negop->icversion_data[j].minor;
 274                                 found_match = true;
 275                                 break;
 276                         }
 277                 }
 278
 279                 if (found_match)
 280                         break;
 281         }
 282
 283         if (!found_match)
 284                 goto fw_error;
 285
 286         found_match = false;
 287
 288         for (i = 0; i < srv_vercnt; i++) {
 289                 srv_major = (srv_version[i] >> 16);
 290                 srv_minor = (srv_version[i] & 0xFFFF);
 291
 292                 for (j = negop->icframe_vercnt;
 293                         (j < negop->icframe_vercnt + negop->icmsg_vercnt);
 294                         j++) {
 295
 296                         if ((negop->icversion_data[j].major == srv_major) &&
 297                                 (negop->icversion_data[j].minor == srv_minor)) {
 298
 299                                 icmsg_major = negop->icversion_data[j].major;
 300                                 icmsg_minor = negop->icversion_data[j].minor;
 301                                 found_match = true;
 302                                 break;
 303                         }
 304                 }
 305
 306                 if (found_match)
 307                         break;
 308         }
 309
 310         /*
 311          * Respond with the framework and service
 312          * version numbers we can support.
 313          */
 314
 315 fw_error:
 316         if (!found_match) {
 317                 negop->icframe_vercnt = 0;
 318                 negop->icmsg_vercnt = 0;
 319         } else {
 320                 negop->icframe_vercnt = 1;
 321                 negop->icmsg_vercnt = 1;
 322         }
 323
 324         if (nego_fw_version)
 325                 *nego_fw_version = (icframe_major << 16) | icframe_minor;
 326
 327         if (nego_srv_version)
 328                 *nego_srv_version = (icmsg_major << 16) | icmsg_minor;
 329
 330         negop->icversion_data[0].major = icframe_major;
 331         negop->icversion_data[0].minor = icframe_minor;
 332         negop->icversion_data[1].major = icmsg_major;
 333         negop->icversion_data[1].minor = icmsg_minor;
 334         return found_match;
 335 }
 336 EXPORT_SYMBOL_GPL(vmbus_prep_negotiate_resp);
 337
 338 /*
 339  * alloc_channel - Allocate and initialize a vmbus channel object
 340  */
 341 static struct vmbus_channel *alloc_channel(void)
 342 {
 343         struct vmbus_channel *channel;
 344
 345         channel = kzalloc(sizeof(*channel), GFP_ATOMIC);
 346         if (!channel)
 347                 return NULL;
 348
 349         spin_lock_init(&channel->sched_lock);
 350         init_completion(&channel->rescind_event);
 351
 352         INIT_LIST_HEAD(&channel->sc_list);
 353
 354         tasklet_init(&channel->callback_event,
 355                      vmbus_on_event, (unsigned long)channel);
 356
 357         hv_ringbuffer_pre_init(channel);
 358
 359         return channel;
 360 }
 361
 362 /*
 363  * free_channel - Release the resources used by the vmbus channel object
 364  */
 365 static void free_channel(struct vmbus_channel *channel)
 366 {
 367         tasklet_kill(&channel->callback_event);
 368         vmbus_remove_channel_attr_group(channel);
 369
 370         kobject_put(&channel->kobj);
 371 }
 372
 373 void vmbus_channel_map_relid(struct vmbus_channel *channel)
 374 {
 375         if (WARN_ON(channel->offermsg.child_relid >= MAX_CHANNEL_RELIDS))
 376                 return;
 377         /*
 378          * The mapping of the channel's relid is visible from the CPUs that
 379          * execute vmbus_chan_sched() by the time that vmbus_chan_sched() will
 380          * execute:
 381          *
 382          *  (a) In the "normal (i.e., not resuming from hibernation)" path,
 383          *      the full barrier in smp_store_mb() guarantees that the store
 384          *      is propagated to all CPUs before the add_channel_work work
 385          *      is queued.  In turn, add_channel_work is queued before the
 386          *      channel's ring buffer is allocated/initialized and the
 387          *      OPENCHANNEL message for the channel is sent in vmbus_open().
 388          *      Hyper-V won't start sending the interrupts for the channel
 389          *      before the OPENCHANNEL message is acked.  The memory barrier
 390          *      in vmbus_chan_sched() -> sync_test_and_clear_bit() ensures
 391          *      that vmbus_chan_sched() must find the channel's relid in
 392          *      recv_int_page before retrieving the channel pointer from the
 393          *      array of channels.
 394          *
 395          *  (b) In the "resuming from hibernation" path, the smp_store_mb()
 396          *      guarantees that the store is propagated to all CPUs before
 397          *      the VMBus connection is marked as ready for the resume event
 398          *      (cf. check_ready_for_resume_event()).  The interrupt handler
 399          *      of the VMBus driver and vmbus_chan_sched() can not run before
 400          *      vmbus_bus_resume() has completed execution (cf. resume_noirq).
 401          */
 402         smp_store_mb(
 403                 vmbus_connection.channels[channel->offermsg.child_relid],
 404                 channel);
 405 }
 406
 407 void vmbus_channel_unmap_relid(struct vmbus_channel *channel)
 408 {
 409         if (WARN_ON(channel->offermsg.child_relid >= MAX_CHANNEL_RELIDS))
 410                 return;
 411         WRITE_ONCE(
 412                 vmbus_connection.channels[channel->offermsg.child_relid],
 413                 NULL);
 414 }
 415
 416 static void vmbus_release_relid(u32 relid)
 417 {
 418         struct vmbus_channel_relid_released msg;
 419         int ret;
 420
 421         memset(&msg, 0, sizeof(struct vmbus_channel_relid_released));
 422         msg.child_relid = relid;
 423         msg.header.msgtype = CHANNELMSG_RELID_RELEASED;
 424         ret = vmbus_post_msg(&msg, sizeof(struct vmbus_channel_relid_released),
 425                              true);
 426
 427         trace_vmbus_release_relid(&msg, ret);
 428 }
 429
 430 void hv_process_channel_removal(struct vmbus_channel *channel)
 431 {
 432         lockdep_assert_held(&vmbus_connection.channel_mutex);
 433         BUG_ON(!channel->rescind);
 434
 435         /*
 436          * hv_process_channel_removal() could find INVALID_RELID only for
 437          * hv_sock channels.  See the inline comments in vmbus_onoffer().
 438          */
 439         WARN_ON(channel->offermsg.child_relid == INVALID_RELID &&
 440                 !is_hvsock_channel(channel));
 441
 442         /*
 443          * Upon suspend, an in-use hv_sock channel is removed from the array of
 444          * channels and the relid is invalidated.  After hibernation, when the
 445          * user-space appplication destroys the channel, it's unnecessary and
 446          * unsafe to remove the channel from the array of channels.  See also
 447          * the inline comments before the call of vmbus_release_relid() below.
 448          */
 449         if (channel->offermsg.child_relid != INVALID_RELID)
 450                 vmbus_channel_unmap_relid(channel);
 451
 452         if (channel->primary_channel == NULL)
 453                 list_del(&channel->listentry);
 454         else
 455                 list_del(&channel->sc_list);
 456
 457         /*
 458          * If this is a "perf" channel, updates the hv_numa_map[] masks so that
 459          * init_vp_index() can (re-)use the CPU.
 460          */
 461         if (hv_is_perf_channel(channel))
 462                 hv_clear_alloced_cpu(channel->target_cpu);
 463
 464         /*
 465          * Upon suspend, an in-use hv_sock channel is marked as "rescinded" and
 466          * the relid is invalidated; after hibernation, when the user-space app
 467          * destroys the channel, the relid is INVALID_RELID, and in this case
 468          * it's unnecessary and unsafe to release the old relid, since the same
 469          * relid can refer to a completely different channel now.
 470          */
 471         if (channel->offermsg.child_relid != INVALID_RELID)
 472                 vmbus_release_relid(channel->offermsg.child_relid);
 473
 474         free_channel(channel);
 475 }
 476
 477 void vmbus_free_channels(void)
 478 {
 479         struct vmbus_channel *channel, *tmp;
 480
 481         list_for_each_entry_safe(channel, tmp, &vmbus_connection.chn_list,
 482                 listentry) {
 483                 /* hv_process_channel_removal() needs this */
 484                 channel->rescind = true;
 485
 486                 vmbus_device_unregister(channel->device_obj);
 487         }
 488 }
 489
 490 /* Note: the function can run concurrently for primary/sub channels. */
 491 static void vmbus_add_channel_work(struct work_struct *work)
 492 {
 493         struct vmbus_channel *newchannel =
 494                 container_of(work, struct vmbus_channel, add_channel_work);
 495         struct vmbus_channel *primary_channel = newchannel->primary_channel;
 496         int ret;
 497
 498         /*
 499          * This state is used to indicate a successful open
 500          * so that when we do close the channel normally, we
 501          * can cleanup properly.
 502          */
 503         newchannel->state = CHANNEL_OPEN_STATE;
 504
 505         if (primary_channel != NULL) {
 506                 /* newchannel is a sub-channel. */
 507                 struct hv_device *dev = primary_channel->device_obj;
 508
 509                 if (vmbus_add_channel_kobj(dev, newchannel))
 510                         goto err_deq_chan;
 511
 512                 if (primary_channel->sc_creation_callback != NULL)
 513                         primary_channel->sc_creation_callback(newchannel);
 514
 515                 newchannel->probe_done = true;
 516                 return;
 517         }
 518
 519         /*
 520          * Start the process of binding the primary channel to the driver
 521          */
 522         newchannel->device_obj = vmbus_device_create(
 523                 &newchannel->offermsg.offer.if_type,
 524                 &newchannel->offermsg.offer.if_instance,
 525                 newchannel);
 526         if (!newchannel->device_obj)
 527                 goto err_deq_chan;
 528
 529         newchannel->device_obj->device_id = newchannel->device_id;
 530         /*
 531          * Add the new device to the bus. This will kick off device-driver
 532          * binding which eventually invokes the device driver's AddDevice()
 533          * method.
 534          */
 535         ret = vmbus_device_register(newchannel->device_obj);
 536
 537         if (ret != 0) {
 538                 pr_err("unable to add child device object (relid %d)\n",
 539                         newchannel->offermsg.child_relid);
 540                 kfree(newchannel->device_obj);
 541                 goto err_deq_chan;
 542         }
 543
 544         newchannel->probe_done = true;
 545         return;
 546
 547 err_deq_chan:
 548         mutex_lock(&vmbus_connection.channel_mutex);
 549
 550         /*
 551          * We need to set the flag, otherwise
 552          * vmbus_onoffer_rescind() can be blocked.
 553          */
 554         newchannel->probe_done = true;
 555
 556         if (primary_channel == NULL)
 557                 list_del(&newchannel->listentry);
 558         else
 559                 list_del(&newchannel->sc_list);
 560
 561         /* vmbus_process_offer() has mapped the channel. */
 562         vmbus_channel_unmap_relid(newchannel);
 563
 564         mutex_unlock(&vmbus_connection.channel_mutex);
 565
 566         vmbus_release_relid(newchannel->offermsg.child_relid);
 567
 568         free_channel(newchannel);
 569 }
 570
 571 /*
 572  * vmbus_process_offer - Process the offer by creating a channel/device
 573  * associated with this offer
 574  */
 575 static void vmbus_process_offer(struct vmbus_channel *newchannel)
 576 {
 577         struct vmbus_channel *channel;
 578         struct workqueue_struct *wq;
 579         bool fnew = true;
 580
 581         /*
 582          * Synchronize vmbus_process_offer() and CPU hotplugging:
 583          *
 584          * CPU1                         CPU2
 585          *
 586          * [vmbus_process_offer()]      [Hot removal of the CPU]
 587          *
 588          * CPU_READ_LOCK                CPUS_WRITE_LOCK
 589          * LOAD cpu_online_mask         SEARCH chn_list
 590          * STORE target_cpu             LOAD target_cpu
 591          * INSERT chn_list              STORE cpu_online_mask
 592          * CPUS_READ_UNLOCK             CPUS_WRITE_UNLOCK
 593          *
 594          * Forbids: CPU1's LOAD from *not* seing CPU2's STORE &&
 595          *              CPU2's SEARCH from *not* seeing CPU1's INSERT
 596          *
 597          * Forbids: CPU2's SEARCH from seeing CPU1's INSERT &&
 598          *              CPU2's LOAD from *not* seing CPU1's STORE
 599          */
 600         cpus_read_lock();
 601
 602         /*
 603          * Serializes the modifications of the chn_list list as well as
 604          * the accesses to next_numa_node_id in init_vp_index().
 605          */
 606         mutex_lock(&vmbus_connection.channel_mutex);
 607
 608         init_vp_index(newchannel);
 609
 610         /* Remember the channels that should be cleaned up upon suspend. */
 611         if (is_hvsock_channel(newchannel) || is_sub_channel(newchannel))
 612                 atomic_inc(&vmbus_connection.nr_chan_close_on_suspend);
 613
 614         /*
 615          * Now that we have acquired the channel_mutex,
 616          * we can release the potentially racing rescind thread.
 617          */
 618         atomic_dec(&vmbus_connection.offer_in_progress);
 619
 620         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 621                 if (guid_equal(&channel->offermsg.offer.if_type,
 622                                &newchannel->offermsg.offer.if_type) &&
 623                     guid_equal(&channel->offermsg.offer.if_instance,
 624                                &newchannel->offermsg.offer.if_instance)) {
 625                         fnew = false;
 626                         break;
 627                 }
 628         }
 629
 630         if (fnew) {
 631                 list_add_tail(&newchannel->listentry,
 632                               &vmbus_connection.chn_list);
 633         } else {
 634                 /*
 635                  * Check to see if this is a valid sub-channel.
 636                  */
 637                 if (newchannel->offermsg.offer.sub_channel_index == 0) {
 638                         mutex_unlock(&vmbus_connection.channel_mutex);
 639                         /*
 640                          * Don't call free_channel(), because newchannel->kobj
 641                          * is not initialized yet.
 642                          */
 643                         kfree(newchannel);
 644                         WARN_ON_ONCE(1);
 645                         return;
 646                 }
 647                 /*
 648                  * Process the sub-channel.
 649                  */
 650                 newchannel->primary_channel = channel;
 651                 list_add_tail(&newchannel->sc_list, &channel->sc_list);
 652         }
 653
 654         vmbus_channel_map_relid(newchannel);
 655
 656         mutex_unlock(&vmbus_connection.channel_mutex);
 657         cpus_read_unlock();
 658
 659         /*
 660          * vmbus_process_offer() mustn't call channel->sc_creation_callback()
 661          * directly for sub-channels, because sc_creation_callback() ->
 662          * vmbus_open() may never get the host's response to the
 663          * OPEN_CHANNEL message (the host may rescind a channel at any time,
 664          * e.g. in the case of hot removing a NIC), and vmbus_onoffer_rescind()
 665          * may not wake up the vmbus_open() as it's blocked due to a non-zero
 666          * vmbus_connection.offer_in_progress, and finally we have a deadlock.
 667          *
 668          * The above is also true for primary channels, if the related device
 669          * drivers use sync probing mode by default.
 670          *
 671          * And, usually the handling of primary channels and sub-channels can
 672          * depend on each other, so we should offload them to different
 673          * workqueues to avoid possible deadlock, e.g. in sync-probing mode,
 674          * NIC1's netvsc_subchan_work() can race with NIC2's netvsc_probe() ->
 675          * rtnl_lock(), and causes deadlock: the former gets the rtnl_lock
 676          * and waits for all the sub-channels to appear, but the latter
 677          * can't get the rtnl_lock and this blocks the handling of
 678          * sub-channels.
 679          */
 680         INIT_WORK(&newchannel->add_channel_work, vmbus_add_channel_work);
 681         wq = fnew ? vmbus_connection.handle_primary_chan_wq :
 682                     vmbus_connection.handle_sub_chan_wq;
 683         queue_work(wq, &newchannel->add_channel_work);
 684 }
 685
 686 /*
 687  * We use this state to statically distribute the channel interrupt load.
 688  */
 689 static int next_numa_node_id;
 690
 691 /*
 692  * Starting with Win8, we can statically distribute the incoming
 693  * channel interrupt load by binding a channel to VCPU.
 694  *
 695  * For pre-win8 hosts or non-performance critical channels we assign the
 696  * VMBUS_CONNECT_CPU.
 697  *
 698  * Starting with win8, performance critical channels will be distributed
 699  * evenly among all the available NUMA nodes.  Once the node is assigned,
 700  * we will assign the CPU based on a simple round robin scheme.
 701  */
 702 static void init_vp_index(struct vmbus_channel *channel)
 703 {
 704         bool perf_chn = hv_is_perf_channel(channel);
 705         cpumask_var_t available_mask;
 706         struct cpumask *alloced_mask;
 707         u32 target_cpu;
 708         int numa_node;
 709
 710         if ((vmbus_proto_version == VERSION_WS2008) ||
 711             (vmbus_proto_version == VERSION_WIN7) || (!perf_chn) ||
 712             !alloc_cpumask_var(&available_mask, GFP_KERNEL)) {
 713                 /*
 714                  * Prior to win8, all channel interrupts are
 715                  * delivered on VMBUS_CONNECT_CPU.
 716                  * Also if the channel is not a performance critical
 717                  * channel, bind it to VMBUS_CONNECT_CPU.
 718                  * In case alloc_cpumask_var() fails, bind it to
 719                  * VMBUS_CONNECT_CPU.
 720                  */
 721                 channel->target_cpu = VMBUS_CONNECT_CPU;
 722                 if (perf_chn)
 723                         hv_set_alloced_cpu(VMBUS_CONNECT_CPU);
 724                 return;
 725         }
 726
 727         while (true) {
 728                 numa_node = next_numa_node_id++;
 729                 if (numa_node == nr_node_ids) {
 730                         next_numa_node_id = 0;
 731                         continue;
 732                 }
 733                 if (cpumask_empty(cpumask_of_node(numa_node)))
 734                         continue;
 735                 break;
 736         }
 737         alloced_mask = &hv_context.hv_numa_map[numa_node];
 738
 739         if (cpumask_weight(alloced_mask) ==
 740             cpumask_weight(cpumask_of_node(numa_node))) {
 741                 /*
 742                  * We have cycled through all the CPUs in the node;
 743                  * reset the alloced map.
 744                  */
 745                 cpumask_clear(alloced_mask);
 746         }
 747
 748         cpumask_xor(available_mask, alloced_mask, cpumask_of_node(numa_node));
 749
 750         target_cpu = cpumask_first(available_mask);
 751         cpumask_set_cpu(target_cpu, alloced_mask);
 752
 753         channel->target_cpu = target_cpu;
 754
 755         free_cpumask_var(available_mask);
 756 }
 757
 758 static void vmbus_wait_for_unload(void)
 759 {
 760         int cpu;
 761         void *page_addr;
 762         struct hv_message *msg;
 763         struct vmbus_channel_message_header *hdr;
 764         u32 message_type, i;
 765
 766         /*
 767          * CHANNELMSG_UNLOAD_RESPONSE is always delivered to the CPU which was
 768          * used for initial contact or to CPU0 depending on host version. When
 769          * we're crashing on a different CPU let's hope that IRQ handler on
 770          * the cpu which receives CHANNELMSG_UNLOAD_RESPONSE is still
 771          * functional and vmbus_unload_response() will complete
 772          * vmbus_connection.unload_event. If not, the last thing we can do is
 773          * read message pages for all CPUs directly.
 774          *
 775          * Wait no more than 10 seconds so that the panic path can't get
 776          * hung forever in case the response message isn't seen.
 777          */
 778         for (i = 0; i < 1000; i++) {
 779                 if (completion_done(&vmbus_connection.unload_event))
 780                         break;
 781
 782                 for_each_online_cpu(cpu) {
 783                         struct hv_per_cpu_context *hv_cpu
 784                                 = per_cpu_ptr(hv_context.cpu_context, cpu);
 785
 786                         page_addr = hv_cpu->synic_message_page;
 787                         msg = (struct hv_message *)page_addr
 788                                 + VMBUS_MESSAGE_SINT;
 789
 790                         message_type = READ_ONCE(msg->header.message_type);
 791                         if (message_type == HVMSG_NONE)
 792                                 continue;
 793
 794                         hdr = (struct vmbus_channel_message_header *)
 795                                 msg->u.payload;
 796
 797                         if (hdr->msgtype == CHANNELMSG_UNLOAD_RESPONSE)
 798                                 complete(&vmbus_connection.unload_event);
 799
 800                         vmbus_signal_eom(msg, message_type);
 801                 }
 802
 803                 mdelay(10);
 804         }
 805
 806         /*
 807          * We're crashing and already got the UNLOAD_RESPONSE, cleanup all
 808          * maybe-pending messages on all CPUs to be able to receive new
 809          * messages after we reconnect.
 810          */
 811         for_each_online_cpu(cpu) {
 812                 struct hv_per_cpu_context *hv_cpu
 813                         = per_cpu_ptr(hv_context.cpu_context, cpu);
 814
 815                 page_addr = hv_cpu->synic_message_page;
 816                 msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
 817                 msg->header.message_type = HVMSG_NONE;
 818         }
 819 }
 820
 821 /*
 822  * vmbus_unload_response - Handler for the unload response.
 823  */
 824 static void vmbus_unload_response(struct vmbus_channel_message_header *hdr)
 825 {
 826         /*
 827          * This is a global event; just wakeup the waiting thread.
 828          * Once we successfully unload, we can cleanup the monitor state.
 829          */
 830         complete(&vmbus_connection.unload_event);
 831 }
 832
 833 void vmbus_initiate_unload(bool crash)
 834 {
 835         struct vmbus_channel_message_header hdr;
 836
 837         if (xchg(&vmbus_connection.conn_state, DISCONNECTED) == DISCONNECTED)
 838                 return;
 839
 840         /* Pre-Win2012R2 hosts don't support reconnect */
 841         if (vmbus_proto_version < VERSION_WIN8_1)
 842                 return;
 843
 844         init_completion(&vmbus_connection.unload_event);
 845         memset(&hdr, 0, sizeof(struct vmbus_channel_message_header));
 846         hdr.msgtype = CHANNELMSG_UNLOAD;
 847         vmbus_post_msg(&hdr, sizeof(struct vmbus_channel_message_header),
 848                        !crash);
 849
 850         /*
 851          * vmbus_initiate_unload() is also called on crash and the crash can be
 852          * happening in an interrupt context, where scheduling is impossible.
 853          */
 854         if (!crash)
 855                 wait_for_completion(&vmbus_connection.unload_event);
 856         else
 857                 vmbus_wait_for_unload();
 858 }
 859
 860 static void check_ready_for_resume_event(void)
 861 {
 862         /*
 863          * If all the old primary channels have been fixed up, then it's safe
 864          * to resume.
 865          */
 866         if (atomic_dec_and_test(&vmbus_connection.nr_chan_fixup_on_resume))
 867                 complete(&vmbus_connection.ready_for_resume_event);
 868 }
 869
 870 static void vmbus_setup_channel_state(struct vmbus_channel *channel,
 871                                       struct vmbus_channel_offer_channel *offer)
 872 {
 873         /*
 874          * Setup state for signalling the host.
 875          */
 876         channel->sig_event = VMBUS_EVENT_CONNECTION_ID;
 877
 878         if (vmbus_proto_version != VERSION_WS2008) {
 879                 channel->is_dedicated_interrupt =
 880                                 (offer->is_dedicated_interrupt != 0);
 881                 channel->sig_event = offer->connection_id;
 882         }
 883
 884         memcpy(&channel->offermsg, offer,
 885                sizeof(struct vmbus_channel_offer_channel));
 886         channel->monitor_grp = (u8)offer->monitorid / 32;
 887         channel->monitor_bit = (u8)offer->monitorid % 32;
 888         channel->device_id = hv_get_dev_type(channel);
 889 }
 890
 891 /*
 892  * find_primary_channel_by_offer - Get the channel object given the new offer.
 893  * This is only used in the resume path of hibernation.
 894  */
 895 static struct vmbus_channel *
 896 find_primary_channel_by_offer(const struct vmbus_channel_offer_channel *offer)
 897 {
 898         struct vmbus_channel *channel = NULL, *iter;
 899         const guid_t *inst1, *inst2;
 900
 901         /* Ignore sub-channel offers. */
 902         if (offer->offer.sub_channel_index != 0)
 903                 return NULL;
 904
 905         mutex_lock(&vmbus_connection.channel_mutex);
 906
 907         list_for_each_entry(iter, &vmbus_connection.chn_list, listentry) {
 908                 inst1 = &iter->offermsg.offer.if_instance;
 909                 inst2 = &offer->offer.if_instance;
 910
 911                 if (guid_equal(inst1, inst2)) {
 912                         channel = iter;
 913                         break;
 914                 }
 915         }
 916
 917         mutex_unlock(&vmbus_connection.channel_mutex);
 918
 919         return channel;
 920 }
 921
 922 static bool vmbus_is_valid_device(const guid_t *guid)
 923 {
 924         u16 i;
 925
 926         if (!hv_is_isolation_supported())
 927                 return true;
 928
 929         for (i = 0; i < ARRAY_SIZE(vmbus_devs); i++) {
 930                 if (guid_equal(guid, &vmbus_devs[i].guid))
 931                         return vmbus_devs[i].allowed_in_isolated;
 932         }
 933         return false;
 934 }
 935
 936 /*
 937  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
 938  *
 939  */
 940 static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 941 {
 942         struct vmbus_channel_offer_channel *offer;
 943         struct vmbus_channel *oldchannel, *newchannel;
 944         size_t offer_sz;
 945
 946         offer = (struct vmbus_channel_offer_channel *)hdr;
 947
 948         trace_vmbus_onoffer(offer);
 949
 950         if (!vmbus_is_valid_device(&offer->offer.if_type)) {
 951                 pr_err_ratelimited("Invalid offer %d from the host supporting isolation\n",
 952                                    offer->child_relid);
 953                 atomic_dec(&vmbus_connection.offer_in_progress);
 954                 return;
 955         }
 956
 957         oldchannel = find_primary_channel_by_offer(offer);
 958
 959         if (oldchannel != NULL) {
 960                 /*
 961                  * We're resuming from hibernation: all the sub-channel and
 962                  * hv_sock channels we had before the hibernation should have
 963                  * been cleaned up, and now we must be seeing a re-offered
 964                  * primary channel that we had before the hibernation.
 965                  */
 966
 967                 /*
 968                  * { Initially: channel relid = INVALID_RELID,
 969                  *              channels[valid_relid] = NULL }
 970                  *
 971                  * CPU1                                 CPU2
 972                  *
 973                  * [vmbus_onoffer()]                    [vmbus_device_release()]
 974                  *
 975                  * LOCK channel_mutex                   LOCK channel_mutex
 976                  * STORE channel relid = valid_relid    LOAD r1 = channel relid
 977                  * MAP_RELID channel                    if (r1 != INVALID_RELID)
 978                  * UNLOCK channel_mutex                   UNMAP_RELID channel
 979                  *                                      UNLOCK channel_mutex
 980                  *
 981                  * Forbids: r1 == valid_relid &&
 982                  *              channels[valid_relid] == channel
 983                  *
 984                  * Note.  r1 can be INVALID_RELID only for an hv_sock channel.
 985                  * None of the hv_sock channels which were present before the
 986                  * suspend are re-offered upon the resume.  See the WARN_ON()
 987                  * in hv_process_channel_removal().
 988                  */
 989                 mutex_lock(&vmbus_connection.channel_mutex);
 990
 991                 atomic_dec(&vmbus_connection.offer_in_progress);
 992
 993                 WARN_ON(oldchannel->offermsg.child_relid != INVALID_RELID);
 994                 /* Fix up the relid. */
 995                 oldchannel->offermsg.child_relid = offer->child_relid;
 996
 997                 offer_sz = sizeof(*offer);
 998                 if (memcmp(offer, &oldchannel->offermsg, offer_sz) != 0) {
 999                         /*
1000                          * This is not an error, since the host can also change
1001                          * the other field(s) of the offer, e.g. on WS RS5
1002                          * (Build 17763), the offer->connection_id of the
1003                          * Mellanox VF vmbus device can change when the host
1004                          * reoffers the device upon resume.
1005                          */
1006                         pr_debug("vmbus offer changed: relid=%d\n",
1007                                  offer->child_relid);
1008
1009                         print_hex_dump_debug("Old vmbus offer: ",
1010                                              DUMP_PREFIX_OFFSET, 16, 4,
1011                                              &oldchannel->offermsg, offer_sz,
1012                                              false);
1013                         print_hex_dump_debug("New vmbus offer: ",
1014                                              DUMP_PREFIX_OFFSET, 16, 4,
1015                                              offer, offer_sz, false);
1016
1017                         /* Fix up the old channel. */
1018                         vmbus_setup_channel_state(oldchannel, offer);
1019                 }
1020
1021                 /* Add the channel back to the array of channels. */
1022                 vmbus_channel_map_relid(oldchannel);
1023                 check_ready_for_resume_event();
1024
1025                 mutex_unlock(&vmbus_connection.channel_mutex);
1026                 return;
1027         }
1028
1029         /* Allocate the channel object and save this offer. */
1030         newchannel = alloc_channel();
1031         if (!newchannel) {
1032                 vmbus_release_relid(offer->child_relid);
1033                 atomic_dec(&vmbus_connection.offer_in_progress);
1034                 pr_err("Unable to allocate channel object\n");
1035                 return;
1036         }
1037
1038         vmbus_setup_channel_state(newchannel, offer);
1039
1040         vmbus_process_offer(newchannel);
1041 }
1042
1043 static void check_ready_for_suspend_event(void)
1044 {
1045         /*
1046          * If all the sub-channels or hv_sock channels have been cleaned up,
1047          * then it's safe to suspend.
1048          */
1049         if (atomic_dec_and_test(&vmbus_connection.nr_chan_close_on_suspend))
1050                 complete(&vmbus_connection.ready_for_suspend_event);
1051 }
1052
1053 /*
1054  * vmbus_onoffer_rescind - Rescind offer handler.
1055  *
1056  * We queue a work item to process this offer synchronously
1057  */
1058 static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
1059 {
1060         struct vmbus_channel_rescind_offer *rescind;
1061         struct vmbus_channel *channel;
1062         struct device *dev;
1063         bool clean_up_chan_for_suspend;
1064
1065         rescind = (struct vmbus_channel_rescind_offer *)hdr;
1066
1067         trace_vmbus_onoffer_rescind(rescind);
1068
1069         /*
1070          * The offer msg and the corresponding rescind msg
1071          * from the host are guranteed to be ordered -
1072          * offer comes in first and then the rescind.
1073          * Since we process these events in work elements,
1074          * and with preemption, we may end up processing
1075          * the events out of order.  We rely on the synchronization
1076          * provided by offer_in_progress and by channel_mutex for
1077          * ordering these events:
1078          *
1079          * { Initially: offer_in_progress = 1 }
1080          *
1081          * CPU1                         CPU2
1082          *
1083          * [vmbus_onoffer()]            [vmbus_onoffer_rescind()]
1084          *
1085          * LOCK channel_mutex           WAIT_ON offer_in_progress == 0
1086          * DECREMENT offer_in_progress  LOCK channel_mutex
1087          * STORE channels[]             LOAD channels[]
1088          * UNLOCK channel_mutex         UNLOCK channel_mutex
1089          *
1090          * Forbids: CPU2's LOAD from *not* seeing CPU1's STORE
1091          */
1092
1093         while (atomic_read(&vmbus_connection.offer_in_progress) != 0) {
1094                 /*
1095                  * We wait here until any channel offer is currently
1096                  * being processed.
1097                  */
1098                 msleep(1);
1099         }
1100
1101         mutex_lock(&vmbus_connection.channel_mutex);
1102         channel = relid2channel(rescind->child_relid);
1103         if (channel != NULL) {
1104                 /*
1105                  * Guarantee that no other instance of vmbus_onoffer_rescind()
1106                  * has got a reference to the channel object.  Synchronize on
1107                  * &vmbus_connection.channel_mutex.
1108                  */
1109                 if (channel->rescind_ref) {
1110                         mutex_unlock(&vmbus_connection.channel_mutex);
1111                         return;
1112                 }
1113                 channel->rescind_ref = true;
1114         }
1115         mutex_unlock(&vmbus_connection.channel_mutex);
1116
1117         if (channel == NULL) {
1118                 /*
1119                  * We failed in processing the offer message;
1120                  * we would have cleaned up the relid in that
1121                  * failure path.
1122                  */
1123                 return;
1124         }
1125
1126         clean_up_chan_for_suspend = is_hvsock_channel(channel) ||
1127                                     is_sub_channel(channel);
1128         /*
1129          * Before setting channel->rescind in vmbus_rescind_cleanup(), we
1130          * should make sure the channel callback is not running any more.
1131          */
1132         vmbus_reset_channel_cb(channel);
1133
1134         /*
1135          * Now wait for offer handling to complete.
1136          */
1137         vmbus_rescind_cleanup(channel);
1138         while (READ_ONCE(channel->probe_done) == false) {
1139                 /*
1140                  * We wait here until any channel offer is currently
1141                  * being processed.
1142                  */
1143                 msleep(1);
1144         }
1145
1146         /*
1147          * At this point, the rescind handling can proceed safely.
1148          */
1149
1150         if (channel->device_obj) {
1151                 if (channel->chn_rescind_callback) {
1152                         channel->chn_rescind_callback(channel);
1153
1154                         if (clean_up_chan_for_suspend)
1155                                 check_ready_for_suspend_event();
1156
1157                         return;
1158                 }
1159                 /*
1160                  * We will have to unregister this device from the
1161                  * driver core.
1162                  */
1163                 dev = get_device(&channel->device_obj->device);
1164                 if (dev) {
1165                         vmbus_device_unregister(channel->device_obj);
1166                         put_device(dev);
1167                 }
1168         } else if (channel->primary_channel != NULL) {
1169                 /*
1170                  * Sub-channel is being rescinded. Following is the channel
1171                  * close sequence when initiated from the driveri (refer to
1172                  * vmbus_close() for details):
1173                  * 1. Close all sub-channels first
1174                  * 2. Then close the primary channel.
1175                  */
1176                 mutex_lock(&vmbus_connection.channel_mutex);
1177                 if (channel->state == CHANNEL_OPEN_STATE) {
1178                         /*
1179                          * The channel is currently not open;
1180                          * it is safe for us to cleanup the channel.
1181                          */
1182                         hv_process_channel_removal(channel);
1183                 } else {
1184                         complete(&channel->rescind_event);
1185                 }
1186                 mutex_unlock(&vmbus_connection.channel_mutex);
1187         }
1188
1189         /* The "channel" may have been freed. Do not access it any longer. */
1190
1191         if (clean_up_chan_for_suspend)
1192                 check_ready_for_suspend_event();
1193 }
1194
1195 void vmbus_hvsock_device_unregister(struct vmbus_channel *channel)
1196 {
1197         BUG_ON(!is_hvsock_channel(channel));
1198
1199         /* We always get a rescind msg when a connection is closed. */
1200         while (!READ_ONCE(channel->probe_done) || !READ_ONCE(channel->rescind))
1201                 msleep(1);
1202
1203         vmbus_device_unregister(channel->device_obj);
1204 }
1205 EXPORT_SYMBOL_GPL(vmbus_hvsock_device_unregister);
1206
1207
1208 /*
1209  * vmbus_onoffers_delivered -
1210  * This is invoked when all offers have been delivered.
1211  *
1212  * Nothing to do here.
1213  */
1214 static void vmbus_onoffers_delivered(
1215                         struct vmbus_channel_message_header *hdr)
1216 {
1217 }
1218
1219 /*
1220  * vmbus_onopen_result - Open result handler.
1221  *
1222  * This is invoked when we received a response to our channel open request.
1223  * Find the matching request, copy the response and signal the requesting
1224  * thread.
1225  */
1226 static void vmbus_onopen_result(struct vmbus_channel_message_header *hdr)
1227 {
1228         struct vmbus_channel_open_result *result;
1229         struct vmbus_channel_msginfo *msginfo;
1230         struct vmbus_channel_message_header *requestheader;
1231         struct vmbus_channel_open_channel *openmsg;
1232         unsigned long flags;
1233
1234         result = (struct vmbus_channel_open_result *)hdr;
1235
1236         trace_vmbus_onopen_result(result);
1237
1238         /*
1239          * Find the open msg, copy the result and signal/unblock the wait event
1240          */
1241         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1242
1243         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1244                                 msglistentry) {
1245                 requestheader =
1246                         (struct vmbus_channel_message_header *)msginfo->msg;
1247
1248                 if (requestheader->msgtype == CHANNELMSG_OPENCHANNEL) {
1249                         openmsg =
1250                         (struct vmbus_channel_open_channel *)msginfo->msg;
1251                         if (openmsg->child_relid == result->child_relid &&
1252                             openmsg->openid == result->openid) {
1253                                 memcpy(&msginfo->response.open_result,
1254                                        result,
1255                                        sizeof(
1256                                         struct vmbus_channel_open_result));
1257                                 complete(&msginfo->waitevent);
1258                                 break;
1259                         }
1260                 }
1261         }
1262         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1263 }
1264
1265 /*
1266  * vmbus_ongpadl_created - GPADL created handler.
1267  *
1268  * This is invoked when we received a response to our gpadl create request.
1269  * Find the matching request, copy the response and signal the requesting
1270  * thread.
1271  */
1272 static void vmbus_ongpadl_created(struct vmbus_channel_message_header *hdr)
1273 {
1274         struct vmbus_channel_gpadl_created *gpadlcreated;
1275         struct vmbus_channel_msginfo *msginfo;
1276         struct vmbus_channel_message_header *requestheader;
1277         struct vmbus_channel_gpadl_header *gpadlheader;
1278         unsigned long flags;
1279
1280         gpadlcreated = (struct vmbus_channel_gpadl_created *)hdr;
1281
1282         trace_vmbus_ongpadl_created(gpadlcreated);
1283
1284         /*
1285          * Find the establish msg, copy the result and signal/unblock the wait
1286          * event
1287          */
1288         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1289
1290         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1291                                 msglistentry) {
1292                 requestheader =
1293                         (struct vmbus_channel_message_header *)msginfo->msg;
1294
1295                 if (requestheader->msgtype == CHANNELMSG_GPADL_HEADER) {
1296                         gpadlheader =
1297                         (struct vmbus_channel_gpadl_header *)requestheader;
1298
1299                         if ((gpadlcreated->child_relid ==
1300                              gpadlheader->child_relid) &&
1301                             (gpadlcreated->gpadl == gpadlheader->gpadl)) {
1302                                 memcpy(&msginfo->response.gpadl_created,
1303                                        gpadlcreated,
1304                                        sizeof(
1305                                         struct vmbus_channel_gpadl_created));
1306                                 complete(&msginfo->waitevent);
1307                                 break;
1308                         }
1309                 }
1310         }
1311         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1312 }
1313
1314 /*
1315  * vmbus_onmodifychannel_response - Modify Channel response handler.
1316  *
1317  * This is invoked when we received a response to our channel modify request.
1318  * Find the matching request, copy the response and signal the requesting thread.
1319  */
1320 static void vmbus_onmodifychannel_response(struct vmbus_channel_message_header *hdr)
1321 {
1322         struct vmbus_channel_modifychannel_response *response;
1323         struct vmbus_channel_msginfo *msginfo;
1324         unsigned long flags;
1325
1326         response = (struct vmbus_channel_modifychannel_response *)hdr;
1327
1328         trace_vmbus_onmodifychannel_response(response);
1329
1330         /*
1331          * Find the modify msg, copy the response and signal/unblock the wait event.
1332          */
1333         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1334
1335         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list, msglistentry) {
1336                 struct vmbus_channel_message_header *responseheader =
1337                                 (struct vmbus_channel_message_header *)msginfo->msg;
1338
1339                 if (responseheader->msgtype == CHANNELMSG_MODIFYCHANNEL) {
1340                         struct vmbus_channel_modifychannel *modifymsg;
1341
1342                         modifymsg = (struct vmbus_channel_modifychannel *)msginfo->msg;
1343                         if (modifymsg->child_relid == response->child_relid) {
1344                                 memcpy(&msginfo->response.modify_response, response,
1345                                        sizeof(*response));
1346                                 complete(&msginfo->waitevent);
1347                                 break;
1348                         }
1349                 }
1350         }
1351         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1352 }
1353
1354 /*
1355  * vmbus_ongpadl_torndown - GPADL torndown handler.
1356  *
1357  * This is invoked when we received a response to our gpadl teardown request.
1358  * Find the matching request, copy the response and signal the requesting
1359  * thread.
1360  */
1361 static void vmbus_ongpadl_torndown(
1362                         struct vmbus_channel_message_header *hdr)
1363 {
1364         struct vmbus_channel_gpadl_torndown *gpadl_torndown;
1365         struct vmbus_channel_msginfo *msginfo;
1366         struct vmbus_channel_message_header *requestheader;
1367         struct vmbus_channel_gpadl_teardown *gpadl_teardown;
1368         unsigned long flags;
1369
1370         gpadl_torndown = (struct vmbus_channel_gpadl_torndown *)hdr;
1371
1372         trace_vmbus_ongpadl_torndown(gpadl_torndown);
1373
1374         /*
1375          * Find the open msg, copy the result and signal/unblock the wait event
1376          */
1377         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1378
1379         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1380                                 msglistentry) {
1381                 requestheader =
1382                         (struct vmbus_channel_message_header *)msginfo->msg;
1383
1384                 if (requestheader->msgtype == CHANNELMSG_GPADL_TEARDOWN) {
1385                         gpadl_teardown =
1386                         (struct vmbus_channel_gpadl_teardown *)requestheader;
1387
1388                         if (gpadl_torndown->gpadl == gpadl_teardown->gpadl) {
1389                                 memcpy(&msginfo->response.gpadl_torndown,
1390                                        gpadl_torndown,
1391                                        sizeof(
1392                                         struct vmbus_channel_gpadl_torndown));
1393                                 complete(&msginfo->waitevent);
1394                                 break;
1395                         }
1396                 }
1397         }
1398         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1399 }
1400
1401 /*
1402  * vmbus_onversion_response - Version response handler
1403  *
1404  * This is invoked when we received a response to our initiate contact request.
1405  * Find the matching request, copy the response and signal the requesting
1406  * thread.
1407  */
1408 static void vmbus_onversion_response(
1409                 struct vmbus_channel_message_header *hdr)
1410 {
1411         struct vmbus_channel_msginfo *msginfo;
1412         struct vmbus_channel_message_header *requestheader;
1413         struct vmbus_channel_version_response *version_response;
1414         unsigned long flags;
1415
1416         version_response = (struct vmbus_channel_version_response *)hdr;
1417
1418         trace_vmbus_onversion_response(version_response);
1419
1420         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
1421
1422         list_for_each_entry(msginfo, &vmbus_connection.chn_msg_list,
1423                                 msglistentry) {
1424                 requestheader =
1425                         (struct vmbus_channel_message_header *)msginfo->msg;
1426
1427                 if (requestheader->msgtype ==
1428                     CHANNELMSG_INITIATE_CONTACT) {
1429                         memcpy(&msginfo->response.version_response,
1430                               version_response,
1431                               sizeof(struct vmbus_channel_version_response));
1432                         complete(&msginfo->waitevent);
1433                 }
1434         }
1435         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
1436 }
1437
1438 /* Channel message dispatch table */
1439 const struct vmbus_channel_message_table_entry
1440 channel_message_table[CHANNELMSG_COUNT] = {
1441         { CHANNELMSG_INVALID,                   0, NULL, 0},
1442         { CHANNELMSG_OFFERCHANNEL,              0, vmbus_onoffer,
1443                 sizeof(struct vmbus_channel_offer_channel)},
1444         { CHANNELMSG_RESCIND_CHANNELOFFER,      0, vmbus_onoffer_rescind,
1445                 sizeof(struct vmbus_channel_rescind_offer) },
1446         { CHANNELMSG_REQUESTOFFERS,             0, NULL, 0},
1447         { CHANNELMSG_ALLOFFERS_DELIVERED,       1, vmbus_onoffers_delivered, 0},
1448         { CHANNELMSG_OPENCHANNEL,               0, NULL, 0},
1449         { CHANNELMSG_OPENCHANNEL_RESULT,        1, vmbus_onopen_result,
1450                 sizeof(struct vmbus_channel_open_result)},
1451         { CHANNELMSG_CLOSECHANNEL,              0, NULL, 0},
1452         { CHANNELMSG_GPADL_HEADER,              0, NULL, 0},
1453         { CHANNELMSG_GPADL_BODY,                0, NULL, 0},
1454         { CHANNELMSG_GPADL_CREATED,             1, vmbus_ongpadl_created,
1455                 sizeof(struct vmbus_channel_gpadl_created)},
1456         { CHANNELMSG_GPADL_TEARDOWN,            0, NULL, 0},
1457         { CHANNELMSG_GPADL_TORNDOWN,            1, vmbus_ongpadl_torndown,
1458                 sizeof(struct vmbus_channel_gpadl_torndown) },
1459         { CHANNELMSG_RELID_RELEASED,            0, NULL, 0},
1460         { CHANNELMSG_INITIATE_CONTACT,          0, NULL, 0},
1461         { CHANNELMSG_VERSION_RESPONSE,          1, vmbus_onversion_response,
1462                 sizeof(struct vmbus_channel_version_response)},
1463         { CHANNELMSG_UNLOAD,                    0, NULL, 0},
1464         { CHANNELMSG_UNLOAD_RESPONSE,           1, vmbus_unload_response, 0},
1465         { CHANNELMSG_18,                        0, NULL, 0},
1466         { CHANNELMSG_19,                        0, NULL, 0},
1467         { CHANNELMSG_20,                        0, NULL, 0},
1468         { CHANNELMSG_TL_CONNECT_REQUEST,        0, NULL, 0},
1469         { CHANNELMSG_MODIFYCHANNEL,             0, NULL, 0},
1470         { CHANNELMSG_TL_CONNECT_RESULT,         0, NULL, 0},
1471         { CHANNELMSG_MODIFYCHANNEL_RESPONSE,    1, vmbus_onmodifychannel_response,
1472                 sizeof(struct vmbus_channel_modifychannel_response)},
1473 };
1474
1475 /*
1476  * vmbus_onmessage - Handler for channel protocol messages.
1477  *
1478  * This is invoked in the vmbus worker thread context.
1479  */
1480 void vmbus_onmessage(struct vmbus_channel_message_header *hdr)
1481 {
1482         trace_vmbus_on_message(hdr);
1483
1484         /*
1485          * vmbus_on_msg_dpc() makes sure the hdr->msgtype here can not go
1486          * out of bound and the message_handler pointer can not be NULL.
1487          */
1488         channel_message_table[hdr->msgtype].message_handler(hdr);
1489 }
1490
1491 /*
1492  * vmbus_request_offers - Send a request to get all our pending offers.
1493  */
1494 int vmbus_request_offers(void)
1495 {
1496         struct vmbus_channel_message_header *msg;
1497         struct vmbus_channel_msginfo *msginfo;
1498         int ret;
1499
1500         msginfo = kmalloc(sizeof(*msginfo) +
1501                           sizeof(struct vmbus_channel_message_header),
1502                           GFP_KERNEL);
1503         if (!msginfo)
1504                 return -ENOMEM;
1505
1506         msg = (struct vmbus_channel_message_header *)msginfo->msg;
1507
1508         msg->msgtype = CHANNELMSG_REQUESTOFFERS;
1509
1510         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_message_header),
1511                              true);
1512
1513         trace_vmbus_request_offers(ret);
1514
1515         if (ret != 0) {
1516                 pr_err("Unable to request offers - %d\n", ret);
1517
1518                 goto cleanup;
1519         }
1520
1521 cleanup:
1522         kfree(msginfo);
1523
1524         return ret;
1525 }
1526
1527 static void invoke_sc_cb(struct vmbus_channel *primary_channel)
1528 {
1529         struct list_head *cur, *tmp;
1530         struct vmbus_channel *cur_channel;
1531
1532         if (primary_channel->sc_creation_callback == NULL)
1533                 return;
1534
1535         list_for_each_safe(cur, tmp, &primary_channel->sc_list) {
1536                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
1537
1538                 primary_channel->sc_creation_callback(cur_channel);
1539         }
1540 }
1541
1542 void vmbus_set_sc_create_callback(struct vmbus_channel *primary_channel,
1543                                 void (*sc_cr_cb)(struct vmbus_channel *new_sc))
1544 {
1545         primary_channel->sc_creation_callback = sc_cr_cb;
1546 }
1547 EXPORT_SYMBOL_GPL(vmbus_set_sc_create_callback);
1548
1549 bool vmbus_are_subchannels_present(struct vmbus_channel *primary)
1550 {
1551         bool ret;
1552
1553         ret = !list_empty(&primary->sc_list);
1554
1555         if (ret) {
1556                 /*
1557                  * Invoke the callback on sub-channel creation.
1558                  * This will present a uniform interface to the
1559                  * clients.
1560                  */
1561                 invoke_sc_cb(primary);
1562         }
1563
1564         return ret;
1565 }
1566 EXPORT_SYMBOL_GPL(vmbus_are_subchannels_present);
1567
1568 void vmbus_set_chn_rescind_callback(struct vmbus_channel *channel,
1569                 void (*chn_rescind_cb)(struct vmbus_channel *))
1570 {
1571         channel->chn_rescind_callback = chn_rescind_cb;
1572 }
1573 EXPORT_SYMBOL_GPL(vmbus_set_chn_rescind_callback);