drivers/hv/vmbus_drv.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  *   K. Y. Srinivasan <kys@microsoft.com>
   9  */
  10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/device.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/sysctl.h>
  17 #include <linux/slab.h>
  18 #include <linux/acpi.h>
  19 #include <linux/completion.h>
  20 #include <linux/hyperv.h>
  21 #include <linux/kernel_stat.h>
  22 #include <linux/clockchips.h>
  23 #include <linux/cpu.h>
  24 #include <linux/sched/task_stack.h>
  25
  26 #include <linux/delay.h>
  27 #include <linux/notifier.h>
  28 #include <linux/ptrace.h>
  29 #include <linux/screen_info.h>
  30 #include <linux/kdebug.h>
  31 #include <linux/efi.h>
  32 #include <linux/random.h>
  33 #include <linux/kernel.h>
  34 #include <linux/syscore_ops.h>
  35 #include <clocksource/hyperv_timer.h>
  36 #include "hyperv_vmbus.h"
  37
  38 struct vmbus_dynid {
  39         struct list_head node;
  40         struct hv_vmbus_device_id id;
  41 };
  42
  43 static struct acpi_device  *hv_acpi_dev;
  44
  45 static struct completion probe_event;
  46
  47 static int hyperv_cpuhp_online;
  48
  49 static void *hv_panic_page;
  50
  51 /* Values parsed from ACPI DSDT */
  52 static int vmbus_irq;
  53 int vmbus_interrupt;
  54
  55 /*
  56  * Boolean to control whether to report panic messages over Hyper-V.
  57  *
  58  * It can be set via /proc/sys/kernel/hyperv/record_panic_msg
  59  */
  60 static int sysctl_record_panic_msg = 1;
  61
  62 static int hyperv_report_reg(void)
  63 {
  64         return !sysctl_record_panic_msg || !hv_panic_page;
  65 }
  66
  67 static int hyperv_panic_event(struct notifier_block *nb, unsigned long val,
  68                               void *args)
  69 {
  70         struct pt_regs *regs;
  71
  72         vmbus_initiate_unload(true);
  73
  74         /*
  75          * Hyper-V should be notified only once about a panic.  If we will be
  76          * doing hyperv_report_panic_msg() later with kmsg data, don't do
  77          * the notification here.
  78          */
  79         if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE
  80             && hyperv_report_reg()) {
  81                 regs = current_pt_regs();
  82                 hyperv_report_panic(regs, val, false);
  83         }
  84         return NOTIFY_DONE;
  85 }
  86
  87 static int hyperv_die_event(struct notifier_block *nb, unsigned long val,
  88                             void *args)
  89 {
  90         struct die_args *die = args;
  91         struct pt_regs *regs = die->regs;
  92
  93         /* Don't notify Hyper-V if the die event is other than oops */
  94         if (val != DIE_OOPS)
  95                 return NOTIFY_DONE;
  96
  97         /*
  98          * Hyper-V should be notified only once about a panic.  If we will be
  99          * doing hyperv_report_panic_msg() later with kmsg data, don't do
 100          * the notification here.
 101          */
 102         if (hyperv_report_reg())
 103                 hyperv_report_panic(regs, val, true);
 104         return NOTIFY_DONE;
 105 }
 106
 107 static struct notifier_block hyperv_die_block = {
 108         .notifier_call = hyperv_die_event,
 109 };
 110 static struct notifier_block hyperv_panic_block = {
 111         .notifier_call = hyperv_panic_event,
 112 };
 113
 114 static const char *fb_mmio_name = "fb_range";
 115 static struct resource *fb_mmio;
 116 static struct resource *hyperv_mmio;
 117 static DEFINE_MUTEX(hyperv_mmio_lock);
 118
 119 static int vmbus_exists(void)
 120 {
 121         if (hv_acpi_dev == NULL)
 122                 return -ENODEV;
 123
 124         return 0;
 125 }
 126
 127 static u8 channel_monitor_group(const struct vmbus_channel *channel)
 128 {
 129         return (u8)channel->offermsg.monitorid / 32;
 130 }
 131
 132 static u8 channel_monitor_offset(const struct vmbus_channel *channel)
 133 {
 134         return (u8)channel->offermsg.monitorid % 32;
 135 }
 136
 137 static u32 channel_pending(const struct vmbus_channel *channel,
 138                            const struct hv_monitor_page *monitor_page)
 139 {
 140         u8 monitor_group = channel_monitor_group(channel);
 141
 142         return monitor_page->trigger_group[monitor_group].pending;
 143 }
 144
 145 static u32 channel_latency(const struct vmbus_channel *channel,
 146                            const struct hv_monitor_page *monitor_page)
 147 {
 148         u8 monitor_group = channel_monitor_group(channel);
 149         u8 monitor_offset = channel_monitor_offset(channel);
 150
 151         return monitor_page->latency[monitor_group][monitor_offset];
 152 }
 153
 154 static u32 channel_conn_id(struct vmbus_channel *channel,
 155                            struct hv_monitor_page *monitor_page)
 156 {
 157         u8 monitor_group = channel_monitor_group(channel);
 158         u8 monitor_offset = channel_monitor_offset(channel);
 159         return monitor_page->parameter[monitor_group][monitor_offset].connectionid.u.id;
 160 }
 161
 162 static ssize_t id_show(struct device *dev, struct device_attribute *dev_attr,
 163                        char *buf)
 164 {
 165         struct hv_device *hv_dev = device_to_hv_device(dev);
 166
 167         if (!hv_dev->channel)
 168                 return -ENODEV;
 169         return sprintf(buf, "%d\n", hv_dev->channel->offermsg.child_relid);
 170 }
 171 static DEVICE_ATTR_RO(id);
 172
 173 static ssize_t state_show(struct device *dev, struct device_attribute *dev_attr,
 174                           char *buf)
 175 {
 176         struct hv_device *hv_dev = device_to_hv_device(dev);
 177
 178         if (!hv_dev->channel)
 179                 return -ENODEV;
 180         return sprintf(buf, "%d\n", hv_dev->channel->state);
 181 }
 182 static DEVICE_ATTR_RO(state);
 183
 184 static ssize_t monitor_id_show(struct device *dev,
 185                                struct device_attribute *dev_attr, char *buf)
 186 {
 187         struct hv_device *hv_dev = device_to_hv_device(dev);
 188
 189         if (!hv_dev->channel)
 190                 return -ENODEV;
 191         return sprintf(buf, "%d\n", hv_dev->channel->offermsg.monitorid);
 192 }
 193 static DEVICE_ATTR_RO(monitor_id);
 194
 195 static ssize_t class_id_show(struct device *dev,
 196                                struct device_attribute *dev_attr, char *buf)
 197 {
 198         struct hv_device *hv_dev = device_to_hv_device(dev);
 199
 200         if (!hv_dev->channel)
 201                 return -ENODEV;
 202         return sprintf(buf, "{%pUl}\n",
 203                        &hv_dev->channel->offermsg.offer.if_type);
 204 }
 205 static DEVICE_ATTR_RO(class_id);
 206
 207 static ssize_t device_id_show(struct device *dev,
 208                               struct device_attribute *dev_attr, char *buf)
 209 {
 210         struct hv_device *hv_dev = device_to_hv_device(dev);
 211
 212         if (!hv_dev->channel)
 213                 return -ENODEV;
 214         return sprintf(buf, "{%pUl}\n",
 215                        &hv_dev->channel->offermsg.offer.if_instance);
 216 }
 217 static DEVICE_ATTR_RO(device_id);
 218
 219 static ssize_t modalias_show(struct device *dev,
 220                              struct device_attribute *dev_attr, char *buf)
 221 {
 222         struct hv_device *hv_dev = device_to_hv_device(dev);
 223
 224         return sprintf(buf, "vmbus:%*phN\n", UUID_SIZE, &hv_dev->dev_type);
 225 }
 226 static DEVICE_ATTR_RO(modalias);
 227
 228 #ifdef CONFIG_NUMA
 229 static ssize_t numa_node_show(struct device *dev,
 230                               struct device_attribute *attr, char *buf)
 231 {
 232         struct hv_device *hv_dev = device_to_hv_device(dev);
 233
 234         if (!hv_dev->channel)
 235                 return -ENODEV;
 236
 237         return sprintf(buf, "%d\n", cpu_to_node(hv_dev->channel->target_cpu));
 238 }
 239 static DEVICE_ATTR_RO(numa_node);
 240 #endif
 241
 242 static ssize_t server_monitor_pending_show(struct device *dev,
 243                                            struct device_attribute *dev_attr,
 244                                            char *buf)
 245 {
 246         struct hv_device *hv_dev = device_to_hv_device(dev);
 247
 248         if (!hv_dev->channel)
 249                 return -ENODEV;
 250         return sprintf(buf, "%d\n",
 251                        channel_pending(hv_dev->channel,
 252                                        vmbus_connection.monitor_pages[0]));
 253 }
 254 static DEVICE_ATTR_RO(server_monitor_pending);
 255
 256 static ssize_t client_monitor_pending_show(struct device *dev,
 257                                            struct device_attribute *dev_attr,
 258                                            char *buf)
 259 {
 260         struct hv_device *hv_dev = device_to_hv_device(dev);
 261
 262         if (!hv_dev->channel)
 263                 return -ENODEV;
 264         return sprintf(buf, "%d\n",
 265                        channel_pending(hv_dev->channel,
 266                                        vmbus_connection.monitor_pages[1]));
 267 }
 268 static DEVICE_ATTR_RO(client_monitor_pending);
 269
 270 static ssize_t server_monitor_latency_show(struct device *dev,
 271                                            struct device_attribute *dev_attr,
 272                                            char *buf)
 273 {
 274         struct hv_device *hv_dev = device_to_hv_device(dev);
 275
 276         if (!hv_dev->channel)
 277                 return -ENODEV;
 278         return sprintf(buf, "%d\n",
 279                        channel_latency(hv_dev->channel,
 280                                        vmbus_connection.monitor_pages[0]));
 281 }
 282 static DEVICE_ATTR_RO(server_monitor_latency);
 283
 284 static ssize_t client_monitor_latency_show(struct device *dev,
 285                                            struct device_attribute *dev_attr,
 286                                            char *buf)
 287 {
 288         struct hv_device *hv_dev = device_to_hv_device(dev);
 289
 290         if (!hv_dev->channel)
 291                 return -ENODEV;
 292         return sprintf(buf, "%d\n",
 293                        channel_latency(hv_dev->channel,
 294                                        vmbus_connection.monitor_pages[1]));
 295 }
 296 static DEVICE_ATTR_RO(client_monitor_latency);
 297
 298 static ssize_t server_monitor_conn_id_show(struct device *dev,
 299                                            struct device_attribute *dev_attr,
 300                                            char *buf)
 301 {
 302         struct hv_device *hv_dev = device_to_hv_device(dev);
 303
 304         if (!hv_dev->channel)
 305                 return -ENODEV;
 306         return sprintf(buf, "%d\n",
 307                        channel_conn_id(hv_dev->channel,
 308                                        vmbus_connection.monitor_pages[0]));
 309 }
 310 static DEVICE_ATTR_RO(server_monitor_conn_id);
 311
 312 static ssize_t client_monitor_conn_id_show(struct device *dev,
 313                                            struct device_attribute *dev_attr,
 314                                            char *buf)
 315 {
 316         struct hv_device *hv_dev = device_to_hv_device(dev);
 317
 318         if (!hv_dev->channel)
 319                 return -ENODEV;
 320         return sprintf(buf, "%d\n",
 321                        channel_conn_id(hv_dev->channel,
 322                                        vmbus_connection.monitor_pages[1]));
 323 }
 324 static DEVICE_ATTR_RO(client_monitor_conn_id);
 325
 326 static ssize_t out_intr_mask_show(struct device *dev,
 327                                   struct device_attribute *dev_attr, char *buf)
 328 {
 329         struct hv_device *hv_dev = device_to_hv_device(dev);
 330         struct hv_ring_buffer_debug_info outbound;
 331         int ret;
 332
 333         if (!hv_dev->channel)
 334                 return -ENODEV;
 335
 336         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
 337                                           &outbound);
 338         if (ret < 0)
 339                 return ret;
 340
 341         return sprintf(buf, "%d\n", outbound.current_interrupt_mask);
 342 }
 343 static DEVICE_ATTR_RO(out_intr_mask);
 344
 345 static ssize_t out_read_index_show(struct device *dev,
 346                                    struct device_attribute *dev_attr, char *buf)
 347 {
 348         struct hv_device *hv_dev = device_to_hv_device(dev);
 349         struct hv_ring_buffer_debug_info outbound;
 350         int ret;
 351
 352         if (!hv_dev->channel)
 353                 return -ENODEV;
 354
 355         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
 356                                           &outbound);
 357         if (ret < 0)
 358                 return ret;
 359         return sprintf(buf, "%d\n", outbound.current_read_index);
 360 }
 361 static DEVICE_ATTR_RO(out_read_index);
 362
 363 static ssize_t out_write_index_show(struct device *dev,
 364                                     struct device_attribute *dev_attr,
 365                                     char *buf)
 366 {
 367         struct hv_device *hv_dev = device_to_hv_device(dev);
 368         struct hv_ring_buffer_debug_info outbound;
 369         int ret;
 370
 371         if (!hv_dev->channel)
 372                 return -ENODEV;
 373
 374         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
 375                                           &outbound);
 376         if (ret < 0)
 377                 return ret;
 378         return sprintf(buf, "%d\n", outbound.current_write_index);
 379 }
 380 static DEVICE_ATTR_RO(out_write_index);
 381
 382 static ssize_t out_read_bytes_avail_show(struct device *dev,
 383                                          struct device_attribute *dev_attr,
 384                                          char *buf)
 385 {
 386         struct hv_device *hv_dev = device_to_hv_device(dev);
 387         struct hv_ring_buffer_debug_info outbound;
 388         int ret;
 389
 390         if (!hv_dev->channel)
 391                 return -ENODEV;
 392
 393         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
 394                                           &outbound);
 395         if (ret < 0)
 396                 return ret;
 397         return sprintf(buf, "%d\n", outbound.bytes_avail_toread);
 398 }
 399 static DEVICE_ATTR_RO(out_read_bytes_avail);
 400
 401 static ssize_t out_write_bytes_avail_show(struct device *dev,
 402                                           struct device_attribute *dev_attr,
 403                                           char *buf)
 404 {
 405         struct hv_device *hv_dev = device_to_hv_device(dev);
 406         struct hv_ring_buffer_debug_info outbound;
 407         int ret;
 408
 409         if (!hv_dev->channel)
 410                 return -ENODEV;
 411
 412         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
 413                                           &outbound);
 414         if (ret < 0)
 415                 return ret;
 416         return sprintf(buf, "%d\n", outbound.bytes_avail_towrite);
 417 }
 418 static DEVICE_ATTR_RO(out_write_bytes_avail);
 419
 420 static ssize_t in_intr_mask_show(struct device *dev,
 421                                  struct device_attribute *dev_attr, char *buf)
 422 {
 423         struct hv_device *hv_dev = device_to_hv_device(dev);
 424         struct hv_ring_buffer_debug_info inbound;
 425         int ret;
 426
 427         if (!hv_dev->channel)
 428                 return -ENODEV;
 429
 430         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 431         if (ret < 0)
 432                 return ret;
 433
 434         return sprintf(buf, "%d\n", inbound.current_interrupt_mask);
 435 }
 436 static DEVICE_ATTR_RO(in_intr_mask);
 437
 438 static ssize_t in_read_index_show(struct device *dev,
 439                                   struct device_attribute *dev_attr, char *buf)
 440 {
 441         struct hv_device *hv_dev = device_to_hv_device(dev);
 442         struct hv_ring_buffer_debug_info inbound;
 443         int ret;
 444
 445         if (!hv_dev->channel)
 446                 return -ENODEV;
 447
 448         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 449         if (ret < 0)
 450                 return ret;
 451
 452         return sprintf(buf, "%d\n", inbound.current_read_index);
 453 }
 454 static DEVICE_ATTR_RO(in_read_index);
 455
 456 static ssize_t in_write_index_show(struct device *dev,
 457                                    struct device_attribute *dev_attr, char *buf)
 458 {
 459         struct hv_device *hv_dev = device_to_hv_device(dev);
 460         struct hv_ring_buffer_debug_info inbound;
 461         int ret;
 462
 463         if (!hv_dev->channel)
 464                 return -ENODEV;
 465
 466         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 467         if (ret < 0)
 468                 return ret;
 469
 470         return sprintf(buf, "%d\n", inbound.current_write_index);
 471 }
 472 static DEVICE_ATTR_RO(in_write_index);
 473
 474 static ssize_t in_read_bytes_avail_show(struct device *dev,
 475                                         struct device_attribute *dev_attr,
 476                                         char *buf)
 477 {
 478         struct hv_device *hv_dev = device_to_hv_device(dev);
 479         struct hv_ring_buffer_debug_info inbound;
 480         int ret;
 481
 482         if (!hv_dev->channel)
 483                 return -ENODEV;
 484
 485         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 486         if (ret < 0)
 487                 return ret;
 488
 489         return sprintf(buf, "%d\n", inbound.bytes_avail_toread);
 490 }
 491 static DEVICE_ATTR_RO(in_read_bytes_avail);
 492
 493 static ssize_t in_write_bytes_avail_show(struct device *dev,
 494                                          struct device_attribute *dev_attr,
 495                                          char *buf)
 496 {
 497         struct hv_device *hv_dev = device_to_hv_device(dev);
 498         struct hv_ring_buffer_debug_info inbound;
 499         int ret;
 500
 501         if (!hv_dev->channel)
 502                 return -ENODEV;
 503
 504         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 505         if (ret < 0)
 506                 return ret;
 507
 508         return sprintf(buf, "%d\n", inbound.bytes_avail_towrite);
 509 }
 510 static DEVICE_ATTR_RO(in_write_bytes_avail);
 511
 512 static ssize_t channel_vp_mapping_show(struct device *dev,
 513                                        struct device_attribute *dev_attr,
 514                                        char *buf)
 515 {
 516         struct hv_device *hv_dev = device_to_hv_device(dev);
 517         struct vmbus_channel *channel = hv_dev->channel, *cur_sc;
 518         int buf_size = PAGE_SIZE, n_written, tot_written;
 519         struct list_head *cur;
 520
 521         if (!channel)
 522                 return -ENODEV;
 523
 524         mutex_lock(&vmbus_connection.channel_mutex);
 525
 526         tot_written = snprintf(buf, buf_size, "%u:%u\n",
 527                 channel->offermsg.child_relid, channel->target_cpu);
 528
 529         list_for_each(cur, &channel->sc_list) {
 530                 if (tot_written >= buf_size - 1)
 531                         break;
 532
 533                 cur_sc = list_entry(cur, struct vmbus_channel, sc_list);
 534                 n_written = scnprintf(buf + tot_written,
 535                                      buf_size - tot_written,
 536                                      "%u:%u\n",
 537                                      cur_sc->offermsg.child_relid,
 538                                      cur_sc->target_cpu);
 539                 tot_written += n_written;
 540         }
 541
 542         mutex_unlock(&vmbus_connection.channel_mutex);
 543
 544         return tot_written;
 545 }
 546 static DEVICE_ATTR_RO(channel_vp_mapping);
 547
 548 static ssize_t vendor_show(struct device *dev,
 549                            struct device_attribute *dev_attr,
 550                            char *buf)
 551 {
 552         struct hv_device *hv_dev = device_to_hv_device(dev);
 553         return sprintf(buf, "0x%x\n", hv_dev->vendor_id);
 554 }
 555 static DEVICE_ATTR_RO(vendor);
 556
 557 static ssize_t device_show(struct device *dev,
 558                            struct device_attribute *dev_attr,
 559                            char *buf)
 560 {
 561         struct hv_device *hv_dev = device_to_hv_device(dev);
 562         return sprintf(buf, "0x%x\n", hv_dev->device_id);
 563 }
 564 static DEVICE_ATTR_RO(device);
 565
 566 static ssize_t driver_override_store(struct device *dev,
 567                                      struct device_attribute *attr,
 568                                      const char *buf, size_t count)
 569 {
 570         struct hv_device *hv_dev = device_to_hv_device(dev);
 571         char *driver_override, *old, *cp;
 572
 573         /* We need to keep extra room for a newline */
 574         if (count >= (PAGE_SIZE - 1))
 575                 return -EINVAL;
 576
 577         driver_override = kstrndup(buf, count, GFP_KERNEL);
 578         if (!driver_override)
 579                 return -ENOMEM;
 580
 581         cp = strchr(driver_override, '\n');
 582         if (cp)
 583                 *cp = '\0';
 584
 585         device_lock(dev);
 586         old = hv_dev->driver_override;
 587         if (strlen(driver_override)) {
 588                 hv_dev->driver_override = driver_override;
 589         } else {
 590                 kfree(driver_override);
 591                 hv_dev->driver_override = NULL;
 592         }
 593         device_unlock(dev);
 594
 595         kfree(old);
 596
 597         return count;
 598 }
 599
 600 static ssize_t driver_override_show(struct device *dev,
 601                                     struct device_attribute *attr, char *buf)
 602 {
 603         struct hv_device *hv_dev = device_to_hv_device(dev);
 604         ssize_t len;
 605
 606         device_lock(dev);
 607         len = snprintf(buf, PAGE_SIZE, "%s\n", hv_dev->driver_override);
 608         device_unlock(dev);
 609
 610         return len;
 611 }
 612 static DEVICE_ATTR_RW(driver_override);
 613
 614 /* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
 615 static struct attribute *vmbus_dev_attrs[] = {
 616         &dev_attr_id.attr,
 617         &dev_attr_state.attr,
 618         &dev_attr_monitor_id.attr,
 619         &dev_attr_class_id.attr,
 620         &dev_attr_device_id.attr,
 621         &dev_attr_modalias.attr,
 622 #ifdef CONFIG_NUMA
 623         &dev_attr_numa_node.attr,
 624 #endif
 625         &dev_attr_server_monitor_pending.attr,
 626         &dev_attr_client_monitor_pending.attr,
 627         &dev_attr_server_monitor_latency.attr,
 628         &dev_attr_client_monitor_latency.attr,
 629         &dev_attr_server_monitor_conn_id.attr,
 630         &dev_attr_client_monitor_conn_id.attr,
 631         &dev_attr_out_intr_mask.attr,
 632         &dev_attr_out_read_index.attr,
 633         &dev_attr_out_write_index.attr,
 634         &dev_attr_out_read_bytes_avail.attr,
 635         &dev_attr_out_write_bytes_avail.attr,
 636         &dev_attr_in_intr_mask.attr,
 637         &dev_attr_in_read_index.attr,
 638         &dev_attr_in_write_index.attr,
 639         &dev_attr_in_read_bytes_avail.attr,
 640         &dev_attr_in_write_bytes_avail.attr,
 641         &dev_attr_channel_vp_mapping.attr,
 642         &dev_attr_vendor.attr,
 643         &dev_attr_device.attr,
 644         &dev_attr_driver_override.attr,
 645         NULL,
 646 };
 647
 648 /*
 649  * Device-level attribute_group callback function. Returns the permission for
 650  * each attribute, and returns 0 if an attribute is not visible.
 651  */
 652 static umode_t vmbus_dev_attr_is_visible(struct kobject *kobj,
 653                                          struct attribute *attr, int idx)
 654 {
 655         struct device *dev = kobj_to_dev(kobj);
 656         const struct hv_device *hv_dev = device_to_hv_device(dev);
 657
 658         /* Hide the monitor attributes if the monitor mechanism is not used. */
 659         if (!hv_dev->channel->offermsg.monitor_allocated &&
 660             (attr == &dev_attr_monitor_id.attr ||
 661              attr == &dev_attr_server_monitor_pending.attr ||
 662              attr == &dev_attr_client_monitor_pending.attr ||
 663              attr == &dev_attr_server_monitor_latency.attr ||
 664              attr == &dev_attr_client_monitor_latency.attr ||
 665              attr == &dev_attr_server_monitor_conn_id.attr ||
 666              attr == &dev_attr_client_monitor_conn_id.attr))
 667                 return 0;
 668
 669         return attr->mode;
 670 }
 671
 672 static const struct attribute_group vmbus_dev_group = {
 673         .attrs = vmbus_dev_attrs,
 674         .is_visible = vmbus_dev_attr_is_visible
 675 };
 676 __ATTRIBUTE_GROUPS(vmbus_dev);
 677
 678 /*
 679  * vmbus_uevent - add uevent for our device
 680  *
 681  * This routine is invoked when a device is added or removed on the vmbus to
 682  * generate a uevent to udev in the userspace. The udev will then look at its
 683  * rule and the uevent generated here to load the appropriate driver
 684  *
 685  * The alias string will be of the form vmbus:guid where guid is the string
 686  * representation of the device guid (each byte of the guid will be
 687  * represented with two hex characters.
 688  */
 689 static int vmbus_uevent(struct device *device, struct kobj_uevent_env *env)
 690 {
 691         struct hv_device *dev = device_to_hv_device(device);
 692         const char *format = "MODALIAS=vmbus:%*phN";
 693
 694         return add_uevent_var(env, format, UUID_SIZE, &dev->dev_type);
 695 }
 696
 697 static const struct hv_vmbus_device_id *
 698 hv_vmbus_dev_match(const struct hv_vmbus_device_id *id, const guid_t *guid)
 699 {
 700         if (id == NULL)
 701                 return NULL; /* empty device table */
 702
 703         for (; !guid_is_null(&id->guid); id++)
 704                 if (guid_equal(&id->guid, guid))
 705                         return id;
 706
 707         return NULL;
 708 }
 709
 710 static const struct hv_vmbus_device_id *
 711 hv_vmbus_dynid_match(struct hv_driver *drv, const guid_t *guid)
 712 {
 713         const struct hv_vmbus_device_id *id = NULL;
 714         struct vmbus_dynid *dynid;
 715
 716         spin_lock(&drv->dynids.lock);
 717         list_for_each_entry(dynid, &drv->dynids.list, node) {
 718                 if (guid_equal(&dynid->id.guid, guid)) {
 719                         id = &dynid->id;
 720                         break;
 721                 }
 722         }
 723         spin_unlock(&drv->dynids.lock);
 724
 725         return id;
 726 }
 727
 728 static const struct hv_vmbus_device_id vmbus_device_null;
 729
 730 /*
 731  * Return a matching hv_vmbus_device_id pointer.
 732  * If there is no match, return NULL.
 733  */
 734 static const struct hv_vmbus_device_id *hv_vmbus_get_id(struct hv_driver *drv,
 735                                                         struct hv_device *dev)
 736 {
 737         const guid_t *guid = &dev->dev_type;
 738         const struct hv_vmbus_device_id *id;
 739
 740         /* When driver_override is set, only bind to the matching driver */
 741         if (dev->driver_override && strcmp(dev->driver_override, drv->name))
 742                 return NULL;
 743
 744         /* Look at the dynamic ids first, before the static ones */
 745         id = hv_vmbus_dynid_match(drv, guid);
 746         if (!id)
 747                 id = hv_vmbus_dev_match(drv->id_table, guid);
 748
 749         /* driver_override will always match, send a dummy id */
 750         if (!id && dev->driver_override)
 751                 id = &vmbus_device_null;
 752
 753         return id;
 754 }
 755
 756 /* vmbus_add_dynid - add a new device ID to this driver and re-probe devices */
 757 static int vmbus_add_dynid(struct hv_driver *drv, guid_t *guid)
 758 {
 759         struct vmbus_dynid *dynid;
 760
 761         dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
 762         if (!dynid)
 763                 return -ENOMEM;
 764
 765         dynid->id.guid = *guid;
 766
 767         spin_lock(&drv->dynids.lock);
 768         list_add_tail(&dynid->node, &drv->dynids.list);
 769         spin_unlock(&drv->dynids.lock);
 770
 771         return driver_attach(&drv->driver);
 772 }
 773
 774 static void vmbus_free_dynids(struct hv_driver *drv)
 775 {
 776         struct vmbus_dynid *dynid, *n;
 777
 778         spin_lock(&drv->dynids.lock);
 779         list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
 780                 list_del(&dynid->node);
 781                 kfree(dynid);
 782         }
 783         spin_unlock(&drv->dynids.lock);
 784 }
 785
 786 /*
 787  * store_new_id - sysfs frontend to vmbus_add_dynid()
 788  *
 789  * Allow GUIDs to be added to an existing driver via sysfs.
 790  */
 791 static ssize_t new_id_store(struct device_driver *driver, const char *buf,
 792                             size_t count)
 793 {
 794         struct hv_driver *drv = drv_to_hv_drv(driver);
 795         guid_t guid;
 796         ssize_t retval;
 797
 798         retval = guid_parse(buf, &guid);
 799         if (retval)
 800                 return retval;
 801
 802         if (hv_vmbus_dynid_match(drv, &guid))
 803                 return -EEXIST;
 804
 805         retval = vmbus_add_dynid(drv, &guid);
 806         if (retval)
 807                 return retval;
 808         return count;
 809 }
 810 static DRIVER_ATTR_WO(new_id);
 811
 812 /*
 813  * store_remove_id - remove a PCI device ID from this driver
 814  *
 815  * Removes a dynamic pci device ID to this driver.
 816  */
 817 static ssize_t remove_id_store(struct device_driver *driver, const char *buf,
 818                                size_t count)
 819 {
 820         struct hv_driver *drv = drv_to_hv_drv(driver);
 821         struct vmbus_dynid *dynid, *n;
 822         guid_t guid;
 823         ssize_t retval;
 824
 825         retval = guid_parse(buf, &guid);
 826         if (retval)
 827                 return retval;
 828
 829         retval = -ENODEV;
 830         spin_lock(&drv->dynids.lock);
 831         list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
 832                 struct hv_vmbus_device_id *id = &dynid->id;
 833
 834                 if (guid_equal(&id->guid, &guid)) {
 835                         list_del(&dynid->node);
 836                         kfree(dynid);
 837                         retval = count;
 838                         break;
 839                 }
 840         }
 841         spin_unlock(&drv->dynids.lock);
 842
 843         return retval;
 844 }
 845 static DRIVER_ATTR_WO(remove_id);
 846
 847 static struct attribute *vmbus_drv_attrs[] = {
 848         &driver_attr_new_id.attr,
 849         &driver_attr_remove_id.attr,
 850         NULL,
 851 };
 852 ATTRIBUTE_GROUPS(vmbus_drv);
 853
 854
 855 /*
 856  * vmbus_match - Attempt to match the specified device to the specified driver
 857  */
 858 static int vmbus_match(struct device *device, struct device_driver *driver)
 859 {
 860         struct hv_driver *drv = drv_to_hv_drv(driver);
 861         struct hv_device *hv_dev = device_to_hv_device(device);
 862
 863         /* The hv_sock driver handles all hv_sock offers. */
 864         if (is_hvsock_channel(hv_dev->channel))
 865                 return drv->hvsock;
 866
 867         if (hv_vmbus_get_id(drv, hv_dev))
 868                 return 1;
 869
 870         return 0;
 871 }
 872
 873 /*
 874  * vmbus_probe - Add the new vmbus's child device
 875  */
 876 static int vmbus_probe(struct device *child_device)
 877 {
 878         int ret = 0;
 879         struct hv_driver *drv =
 880                         drv_to_hv_drv(child_device->driver);
 881         struct hv_device *dev = device_to_hv_device(child_device);
 882         const struct hv_vmbus_device_id *dev_id;
 883
 884         dev_id = hv_vmbus_get_id(drv, dev);
 885         if (drv->probe) {
 886                 ret = drv->probe(dev, dev_id);
 887                 if (ret != 0)
 888                         pr_err("probe failed for device %s (%d)\n",
 889                                dev_name(child_device), ret);
 890
 891         } else {
 892                 pr_err("probe not set for driver %s\n",
 893                        dev_name(child_device));
 894                 ret = -ENODEV;
 895         }
 896         return ret;
 897 }
 898
 899 /*
 900  * vmbus_remove - Remove a vmbus device
 901  */
 902 static int vmbus_remove(struct device *child_device)
 903 {
 904         struct hv_driver *drv;
 905         struct hv_device *dev = device_to_hv_device(child_device);
 906
 907         if (child_device->driver) {
 908                 drv = drv_to_hv_drv(child_device->driver);
 909                 if (drv->remove)
 910                         drv->remove(dev);
 911         }
 912
 913         return 0;
 914 }
 915
 916
 917 /*
 918  * vmbus_shutdown - Shutdown a vmbus device
 919  */
 920 static void vmbus_shutdown(struct device *child_device)
 921 {
 922         struct hv_driver *drv;
 923         struct hv_device *dev = device_to_hv_device(child_device);
 924
 925
 926         /* The device may not be attached yet */
 927         if (!child_device->driver)
 928                 return;
 929
 930         drv = drv_to_hv_drv(child_device->driver);
 931
 932         if (drv->shutdown)
 933                 drv->shutdown(dev);
 934 }
 935
 936 #ifdef CONFIG_PM_SLEEP
 937 /*
 938  * vmbus_suspend - Suspend a vmbus device
 939  */
 940 static int vmbus_suspend(struct device *child_device)
 941 {
 942         struct hv_driver *drv;
 943         struct hv_device *dev = device_to_hv_device(child_device);
 944
 945         /* The device may not be attached yet */
 946         if (!child_device->driver)
 947                 return 0;
 948
 949         drv = drv_to_hv_drv(child_device->driver);
 950         if (!drv->suspend)
 951                 return -EOPNOTSUPP;
 952
 953         return drv->suspend(dev);
 954 }
 955
 956 /*
 957  * vmbus_resume - Resume a vmbus device
 958  */
 959 static int vmbus_resume(struct device *child_device)
 960 {
 961         struct hv_driver *drv;
 962         struct hv_device *dev = device_to_hv_device(child_device);
 963
 964         /* The device may not be attached yet */
 965         if (!child_device->driver)
 966                 return 0;
 967
 968         drv = drv_to_hv_drv(child_device->driver);
 969         if (!drv->resume)
 970                 return -EOPNOTSUPP;
 971
 972         return drv->resume(dev);
 973 }
 974 #else
 975 #define vmbus_suspend NULL
 976 #define vmbus_resume NULL
 977 #endif /* CONFIG_PM_SLEEP */
 978
 979 /*
 980  * vmbus_device_release - Final callback release of the vmbus child device
 981  */
 982 static void vmbus_device_release(struct device *device)
 983 {
 984         struct hv_device *hv_dev = device_to_hv_device(device);
 985         struct vmbus_channel *channel = hv_dev->channel;
 986
 987         hv_debug_rm_dev_dir(hv_dev);
 988
 989         mutex_lock(&vmbus_connection.channel_mutex);
 990         hv_process_channel_removal(channel);
 991         mutex_unlock(&vmbus_connection.channel_mutex);
 992         kfree(hv_dev);
 993 }
 994
 995 /*
 996  * Note: we must use the "noirq" ops: see the comment before vmbus_bus_pm.
 997  *
 998  * suspend_noirq/resume_noirq are set to NULL to support Suspend-to-Idle: we
 999  * shouldn't suspend the vmbus devices upon Suspend-to-Idle, otherwise there
1000  * is no way to wake up a Generation-2 VM.
1001  *
1002  * The other 4 ops are for hibernation.
1003  */
1004
1005 static const struct dev_pm_ops vmbus_pm = {
1006         .suspend_noirq  = NULL,
1007         .resume_noirq   = NULL,
1008         .freeze_noirq   = vmbus_suspend,
1009         .thaw_noirq     = vmbus_resume,
1010         .poweroff_noirq = vmbus_suspend,
1011         .restore_noirq  = vmbus_resume,
1012 };
1013
1014 /* The one and only one */
1015 static struct bus_type  hv_bus = {
1016         .name =         "vmbus",
1017         .match =                vmbus_match,
1018         .shutdown =             vmbus_shutdown,
1019         .remove =               vmbus_remove,
1020         .probe =                vmbus_probe,
1021         .uevent =               vmbus_uevent,
1022         .dev_groups =           vmbus_dev_groups,
1023         .drv_groups =           vmbus_drv_groups,
1024         .pm =                   &vmbus_pm,
1025 };
1026
1027 struct onmessage_work_context {
1028         struct work_struct work;
1029         struct {
1030                 struct hv_message_header header;
1031                 u8 payload[];
1032         } msg;
1033 };
1034
1035 static void vmbus_onmessage_work(struct work_struct *work)
1036 {
1037         struct onmessage_work_context *ctx;
1038
1039         /* Do not process messages if we're in DISCONNECTED state */
1040         if (vmbus_connection.conn_state == DISCONNECTED)
1041                 return;
1042
1043         ctx = container_of(work, struct onmessage_work_context,
1044                            work);
1045         vmbus_onmessage((struct vmbus_channel_message_header *)
1046                         &ctx->msg.payload);
1047         kfree(ctx);
1048 }
1049
1050 void vmbus_on_msg_dpc(unsigned long data)
1051 {
1052         struct hv_per_cpu_context *hv_cpu = (void *)data;
1053         void *page_addr = hv_cpu->synic_message_page;
1054         struct hv_message *msg = (struct hv_message *)page_addr +
1055                                   VMBUS_MESSAGE_SINT;
1056         struct vmbus_channel_message_header *hdr;
1057         const struct vmbus_channel_message_table_entry *entry;
1058         struct onmessage_work_context *ctx;
1059         u32 message_type = msg->header.message_type;
1060
1061         /*
1062          * 'enum vmbus_channel_message_type' is supposed to always be 'u32' as
1063          * it is being used in 'struct vmbus_channel_message_header' definition
1064          * which is supposed to match hypervisor ABI.
1065          */
1066         BUILD_BUG_ON(sizeof(enum vmbus_channel_message_type) != sizeof(u32));
1067
1068         if (message_type == HVMSG_NONE)
1069                 /* no msg */
1070                 return;
1071
1072         hdr = (struct vmbus_channel_message_header *)msg->u.payload;
1073
1074         trace_vmbus_on_msg_dpc(hdr);
1075
1076         if (hdr->msgtype >= CHANNELMSG_COUNT) {
1077                 WARN_ONCE(1, "unknown msgtype=%d\n", hdr->msgtype);
1078                 goto msg_handled;
1079         }
1080
1081         if (msg->header.payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT) {
1082                 WARN_ONCE(1, "payload size is too large (%d)\n",
1083                           msg->header.payload_size);
1084                 goto msg_handled;
1085         }
1086
1087         entry = &channel_message_table[hdr->msgtype];
1088
1089         if (!entry->message_handler)
1090                 goto msg_handled;
1091
1092         if (msg->header.payload_size < entry->min_payload_len) {
1093                 WARN_ONCE(1, "message too short: msgtype=%d len=%d\n",
1094                           hdr->msgtype, msg->header.payload_size);
1095                 goto msg_handled;
1096         }
1097
1098         if (entry->handler_type == VMHT_BLOCKING) {
1099                 ctx = kmalloc(sizeof(*ctx) + msg->header.payload_size,
1100                               GFP_ATOMIC);
1101                 if (ctx == NULL)
1102                         return;
1103
1104                 INIT_WORK(&ctx->work, vmbus_onmessage_work);
1105                 memcpy(&ctx->msg, msg, sizeof(msg->header) +
1106                        msg->header.payload_size);
1107
1108                 /*
1109                  * The host can generate a rescind message while we
1110                  * may still be handling the original offer. We deal with
1111                  * this condition by relying on the synchronization provided
1112                  * by offer_in_progress and by channel_mutex.  See also the
1113                  * inline comments in vmbus_onoffer_rescind().
1114                  */
1115                 switch (hdr->msgtype) {
1116                 case CHANNELMSG_RESCIND_CHANNELOFFER:
1117                         /*
1118                          * If we are handling the rescind message;
1119                          * schedule the work on the global work queue.
1120                          *
1121                          * The OFFER message and the RESCIND message should
1122                          * not be handled by the same serialized work queue,
1123                          * because the OFFER handler may call vmbus_open(),
1124                          * which tries to open the channel by sending an
1125                          * OPEN_CHANNEL message to the host and waits for
1126                          * the host's response; however, if the host has
1127                          * rescinded the channel before it receives the
1128                          * OPEN_CHANNEL message, the host just silently
1129                          * ignores the OPEN_CHANNEL message; as a result,
1130                          * the guest's OFFER handler hangs for ever, if we
1131                          * handle the RESCIND message in the same serialized
1132                          * work queue: the RESCIND handler can not start to
1133                          * run before the OFFER handler finishes.
1134                          */
1135                         schedule_work(&ctx->work);
1136                         break;
1137
1138                 case CHANNELMSG_OFFERCHANNEL:
1139                         /*
1140                          * The host sends the offer message of a given channel
1141                          * before sending the rescind message of the same
1142                          * channel.  These messages are sent to the guest's
1143                          * connect CPU; the guest then starts processing them
1144                          * in the tasklet handler on this CPU:
1145                          *
1146                          * VMBUS_CONNECT_CPU
1147                          *
1148                          * [vmbus_on_msg_dpc()]
1149                          * atomic_inc()  // CHANNELMSG_OFFERCHANNEL
1150                          * queue_work()
1151                          * ...
1152                          * [vmbus_on_msg_dpc()]
1153                          * schedule_work()  // CHANNELMSG_RESCIND_CHANNELOFFER
1154                          *
1155                          * We rely on the memory-ordering properties of the
1156                          * queue_work() and schedule_work() primitives, which
1157                          * guarantee that the atomic increment will be visible
1158                          * to the CPUs which will execute the offer & rescind
1159                          * works by the time these works will start execution.
1160                          */
1161                         atomic_inc(&vmbus_connection.offer_in_progress);
1162                         fallthrough;
1163
1164                 default:
1165                         queue_work(vmbus_connection.work_queue, &ctx->work);
1166                 }
1167         } else
1168                 entry->message_handler(hdr);
1169
1170 msg_handled:
1171         vmbus_signal_eom(msg, message_type);
1172 }
1173
1174 #ifdef CONFIG_PM_SLEEP
1175 /*
1176  * Fake RESCIND_CHANNEL messages to clean up hv_sock channels by force for
1177  * hibernation, because hv_sock connections can not persist across hibernation.
1178  */
1179 static void vmbus_force_channel_rescinded(struct vmbus_channel *channel)
1180 {
1181         struct onmessage_work_context *ctx;
1182         struct vmbus_channel_rescind_offer *rescind;
1183
1184         WARN_ON(!is_hvsock_channel(channel));
1185
1186         /*
1187          * Allocation size is small and the allocation should really not fail,
1188          * otherwise the state of the hv_sock connections ends up in limbo.
1189          */
1190         ctx = kzalloc(sizeof(*ctx) + sizeof(*rescind),
1191                       GFP_KERNEL | __GFP_NOFAIL);
1192
1193         /*
1194          * So far, these are not really used by Linux. Just set them to the
1195          * reasonable values conforming to the definitions of the fields.
1196          */
1197         ctx->msg.header.message_type = 1;
1198         ctx->msg.header.payload_size = sizeof(*rescind);
1199
1200         /* These values are actually used by Linux. */
1201         rescind = (struct vmbus_channel_rescind_offer *)ctx->msg.payload;
1202         rescind->header.msgtype = CHANNELMSG_RESCIND_CHANNELOFFER;
1203         rescind->child_relid = channel->offermsg.child_relid;
1204
1205         INIT_WORK(&ctx->work, vmbus_onmessage_work);
1206
1207         queue_work(vmbus_connection.work_queue, &ctx->work);
1208 }
1209 #endif /* CONFIG_PM_SLEEP */
1210
1211 /*
1212  * Schedule all channels with events pending
1213  */
1214 static void vmbus_chan_sched(struct hv_per_cpu_context *hv_cpu)
1215 {
1216         unsigned long *recv_int_page;
1217         u32 maxbits, relid;
1218
1219         if (vmbus_proto_version < VERSION_WIN8) {
1220                 maxbits = MAX_NUM_CHANNELS_SUPPORTED;
1221                 recv_int_page = vmbus_connection.recv_int_page;
1222         } else {
1223                 /*
1224                  * When the host is win8 and beyond, the event page
1225                  * can be directly checked to get the id of the channel
1226                  * that has the interrupt pending.
1227                  */
1228                 void *page_addr = hv_cpu->synic_event_page;
1229                 union hv_synic_event_flags *event
1230                         = (union hv_synic_event_flags *)page_addr +
1231                                                  VMBUS_MESSAGE_SINT;
1232
1233                 maxbits = HV_EVENT_FLAGS_COUNT;
1234                 recv_int_page = event->flags;
1235         }
1236
1237         if (unlikely(!recv_int_page))
1238                 return;
1239
1240         for_each_set_bit(relid, recv_int_page, maxbits) {
1241                 void (*callback_fn)(void *context);
1242                 struct vmbus_channel *channel;
1243
1244                 if (!sync_test_and_clear_bit(relid, recv_int_page))
1245                         continue;
1246
1247                 /* Special case - vmbus channel protocol msg */
1248                 if (relid == 0)
1249                         continue;
1250
1251                 /*
1252                  * Pairs with the kfree_rcu() in vmbus_chan_release().
1253                  * Guarantees that the channel data structure doesn't
1254                  * get freed while the channel pointer below is being
1255                  * dereferenced.
1256                  */
1257                 rcu_read_lock();
1258
1259                 /* Find channel based on relid */
1260                 channel = relid2channel(relid);
1261                 if (channel == NULL)
1262                         goto sched_unlock_rcu;
1263
1264                 if (channel->rescind)
1265                         goto sched_unlock_rcu;
1266
1267                 /*
1268                  * Make sure that the ring buffer data structure doesn't get
1269                  * freed while we dereference the ring buffer pointer.  Test
1270                  * for the channel's onchannel_callback being NULL within a
1271                  * sched_lock critical section.  See also the inline comments
1272                  * in vmbus_reset_channel_cb().
1273                  */
1274                 spin_lock(&channel->sched_lock);
1275
1276                 callback_fn = channel->onchannel_callback;
1277                 if (unlikely(callback_fn == NULL))
1278                         goto sched_unlock;
1279
1280                 trace_vmbus_chan_sched(channel);
1281
1282                 ++channel->interrupts;
1283
1284                 switch (channel->callback_mode) {
1285                 case HV_CALL_ISR:
1286                         (*callback_fn)(channel->channel_callback_context);
1287                         break;
1288
1289                 case HV_CALL_BATCHED:
1290                         hv_begin_read(&channel->inbound);
1291                         fallthrough;
1292                 case HV_CALL_DIRECT:
1293                         tasklet_schedule(&channel->callback_event);
1294                 }
1295
1296 sched_unlock:
1297                 spin_unlock(&channel->sched_lock);
1298 sched_unlock_rcu:
1299                 rcu_read_unlock();
1300         }
1301 }
1302
1303 static void vmbus_isr(void)
1304 {
1305         struct hv_per_cpu_context *hv_cpu
1306                 = this_cpu_ptr(hv_context.cpu_context);
1307         void *page_addr = hv_cpu->synic_event_page;
1308         struct hv_message *msg;
1309         union hv_synic_event_flags *event;
1310         bool handled = false;
1311
1312         if (unlikely(page_addr == NULL))
1313                 return;
1314
1315         event = (union hv_synic_event_flags *)page_addr +
1316                                          VMBUS_MESSAGE_SINT;
1317         /*
1318          * Check for events before checking for messages. This is the order
1319          * in which events and messages are checked in Windows guests on
1320          * Hyper-V, and the Windows team suggested we do the same.
1321          */
1322
1323         if ((vmbus_proto_version == VERSION_WS2008) ||
1324                 (vmbus_proto_version == VERSION_WIN7)) {
1325
1326                 /* Since we are a child, we only need to check bit 0 */
1327                 if (sync_test_and_clear_bit(0, event->flags))
1328                         handled = true;
1329         } else {
1330                 /*
1331                  * Our host is win8 or above. The signaling mechanism
1332                  * has changed and we can directly look at the event page.
1333                  * If bit n is set then we have an interrup on the channel
1334                  * whose id is n.
1335                  */
1336                 handled = true;
1337         }
1338
1339         if (handled)
1340                 vmbus_chan_sched(hv_cpu);
1341
1342         page_addr = hv_cpu->synic_message_page;
1343         msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
1344
1345         /* Check if there are actual msgs to be processed */
1346         if (msg->header.message_type != HVMSG_NONE) {
1347                 if (msg->header.message_type == HVMSG_TIMER_EXPIRED) {
1348                         hv_stimer0_isr();
1349                         vmbus_signal_eom(msg, HVMSG_TIMER_EXPIRED);
1350                 } else
1351                         tasklet_schedule(&hv_cpu->msg_dpc);
1352         }
1353
1354         add_interrupt_randomness(hv_get_vector(), 0);
1355 }
1356
1357 /*
1358  * Callback from kmsg_dump. Grab as much as possible from the end of the kmsg
1359  * buffer and call into Hyper-V to transfer the data.
1360  */
1361 static void hv_kmsg_dump(struct kmsg_dumper *dumper,
1362                          enum kmsg_dump_reason reason)
1363 {
1364         size_t bytes_written;
1365         phys_addr_t panic_pa;
1366
1367         /* We are only interested in panics. */
1368         if ((reason != KMSG_DUMP_PANIC) || (!sysctl_record_panic_msg))
1369                 return;
1370
1371         panic_pa = virt_to_phys(hv_panic_page);
1372
1373         /*
1374          * Write dump contents to the page. No need to synchronize; panic should
1375          * be single-threaded.
1376          */
1377         kmsg_dump_get_buffer(dumper, false, hv_panic_page, HV_HYP_PAGE_SIZE,
1378                              &bytes_written);
1379         if (bytes_written)
1380                 hyperv_report_panic_msg(panic_pa, bytes_written);
1381 }
1382
1383 static struct kmsg_dumper hv_kmsg_dumper = {
1384         .dump = hv_kmsg_dump,
1385 };
1386
1387 static struct ctl_table_header *hv_ctl_table_hdr;
1388
1389 /*
1390  * sysctl option to allow the user to control whether kmsg data should be
1391  * reported to Hyper-V on panic.
1392  */
1393 static struct ctl_table hv_ctl_table[] = {
1394         {
1395                 .procname       = "hyperv_record_panic_msg",
1396                 .data           = &sysctl_record_panic_msg,
1397                 .maxlen         = sizeof(int),
1398                 .mode           = 0644,
1399                 .proc_handler   = proc_dointvec_minmax,
1400                 .extra1         = SYSCTL_ZERO,
1401                 .extra2         = SYSCTL_ONE
1402         },
1403         {}
1404 };
1405
1406 static struct ctl_table hv_root_table[] = {
1407         {
1408                 .procname       = "kernel",
1409                 .mode           = 0555,
1410                 .child          = hv_ctl_table
1411         },
1412         {}
1413 };
1414
1415 /*
1416  * vmbus_bus_init -Main vmbus driver initialization routine.
1417  *
1418  * Here, we
1419  *      - initialize the vmbus driver context
1420  *      - invoke the vmbus hv main init routine
1421  *      - retrieve the channel offers
1422  */
1423 static int vmbus_bus_init(void)
1424 {
1425         int ret;
1426
1427         ret = hv_init();
1428         if (ret != 0) {
1429                 pr_err("Unable to initialize the hypervisor - 0x%x\n", ret);
1430                 return ret;
1431         }
1432
1433         ret = bus_register(&hv_bus);
1434         if (ret)
1435                 return ret;
1436
1437         ret = hv_setup_vmbus_irq(vmbus_irq, vmbus_isr);
1438         if (ret)
1439                 goto err_setup;
1440
1441         ret = hv_synic_alloc();
1442         if (ret)
1443                 goto err_alloc;
1444
1445         /*
1446          * Initialize the per-cpu interrupt state and stimer state.
1447          * Then connect to the host.
1448          */
1449         ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "hyperv/vmbus:online",
1450                                 hv_synic_init, hv_synic_cleanup);
1451         if (ret < 0)
1452                 goto err_cpuhp;
1453         hyperv_cpuhp_online = ret;
1454
1455         ret = vmbus_connect();
1456         if (ret)
1457                 goto err_connect;
1458
1459         /*
1460          * Only register if the crash MSRs are available
1461          */
1462         if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
1463                 u64 hyperv_crash_ctl;
1464                 /*
1465                  * Sysctl registration is not fatal, since by default
1466                  * reporting is enabled.
1467                  */
1468                 hv_ctl_table_hdr = register_sysctl_table(hv_root_table);
1469                 if (!hv_ctl_table_hdr)
1470                         pr_err("Hyper-V: sysctl table register error");
1471
1472                 /*
1473                  * Register for panic kmsg callback only if the right
1474                  * capability is supported by the hypervisor.
1475                  */
1476                 hv_get_crash_ctl(hyperv_crash_ctl);
1477                 if (hyperv_crash_ctl & HV_CRASH_CTL_CRASH_NOTIFY_MSG) {
1478                         hv_panic_page = (void *)hv_alloc_hyperv_zeroed_page();
1479                         if (hv_panic_page) {
1480                                 ret = kmsg_dump_register(&hv_kmsg_dumper);
1481                                 if (ret) {
1482                                         pr_err("Hyper-V: kmsg dump register "
1483                                                 "error 0x%x\n", ret);
1484                                         hv_free_hyperv_page(
1485                                             (unsigned long)hv_panic_page);
1486                                         hv_panic_page = NULL;
1487                                 }
1488                         } else
1489                                 pr_err("Hyper-V: panic message page memory "
1490                                         "allocation failed");
1491                 }
1492
1493                 register_die_notifier(&hyperv_die_block);
1494         }
1495
1496         /*
1497          * Always register the panic notifier because we need to unload
1498          * the VMbus channel connection to prevent any VMbus
1499          * activity after the VM panics.
1500          */
1501         atomic_notifier_chain_register(&panic_notifier_list,
1502                                &hyperv_panic_block);
1503
1504         vmbus_request_offers();
1505
1506         return 0;
1507
1508 err_connect:
1509         cpuhp_remove_state(hyperv_cpuhp_online);
1510 err_cpuhp:
1511         hv_synic_free();
1512 err_alloc:
1513         hv_remove_vmbus_irq();
1514 err_setup:
1515         bus_unregister(&hv_bus);
1516         unregister_sysctl_table(hv_ctl_table_hdr);
1517         hv_ctl_table_hdr = NULL;
1518         return ret;
1519 }
1520
1521 /**
1522  * __vmbus_child_driver_register() - Register a vmbus's driver
1523  * @hv_driver: Pointer to driver structure you want to register
1524  * @owner: owner module of the drv
1525  * @mod_name: module name string
1526  *
1527  * Registers the given driver with Linux through the 'driver_register()' call
1528  * and sets up the hyper-v vmbus handling for this driver.
1529  * It will return the state of the 'driver_register()' call.
1530  *
1531  */
1532 int __vmbus_driver_register(struct hv_driver *hv_driver, struct module *owner, const char *mod_name)
1533 {
1534         int ret;
1535
1536         pr_info("registering driver %s\n", hv_driver->name);
1537
1538         ret = vmbus_exists();
1539         if (ret < 0)
1540                 return ret;
1541
1542         hv_driver->driver.name = hv_driver->name;
1543         hv_driver->driver.owner = owner;
1544         hv_driver->driver.mod_name = mod_name;
1545         hv_driver->driver.bus = &hv_bus;
1546
1547         spin_lock_init(&hv_driver->dynids.lock);
1548         INIT_LIST_HEAD(&hv_driver->dynids.list);
1549
1550         ret = driver_register(&hv_driver->driver);
1551
1552         return ret;
1553 }
1554 EXPORT_SYMBOL_GPL(__vmbus_driver_register);
1555
1556 /**
1557  * vmbus_driver_unregister() - Unregister a vmbus's driver
1558  * @hv_driver: Pointer to driver structure you want to
1559  *             un-register
1560  *
1561  * Un-register the given driver that was previous registered with a call to
1562  * vmbus_driver_register()
1563  */
1564 void vmbus_driver_unregister(struct hv_driver *hv_driver)
1565 {
1566         pr_info("unregistering driver %s\n", hv_driver->name);
1567
1568         if (!vmbus_exists()) {
1569                 driver_unregister(&hv_driver->driver);
1570                 vmbus_free_dynids(hv_driver);
1571         }
1572 }
1573 EXPORT_SYMBOL_GPL(vmbus_driver_unregister);
1574
1575
1576 /*
1577  * Called when last reference to channel is gone.
1578  */
1579 static void vmbus_chan_release(struct kobject *kobj)
1580 {
1581         struct vmbus_channel *channel
1582                 = container_of(kobj, struct vmbus_channel, kobj);
1583
1584         kfree_rcu(channel, rcu);
1585 }
1586
1587 struct vmbus_chan_attribute {
1588         struct attribute attr;
1589         ssize_t (*show)(struct vmbus_channel *chan, char *buf);
1590         ssize_t (*store)(struct vmbus_channel *chan,
1591                          const char *buf, size_t count);
1592 };
1593 #define VMBUS_CHAN_ATTR(_name, _mode, _show, _store) \
1594         struct vmbus_chan_attribute chan_attr_##_name \
1595                 = __ATTR(_name, _mode, _show, _store)
1596 #define VMBUS_CHAN_ATTR_RW(_name) \
1597         struct vmbus_chan_attribute chan_attr_##_name = __ATTR_RW(_name)
1598 #define VMBUS_CHAN_ATTR_RO(_name) \
1599         struct vmbus_chan_attribute chan_attr_##_name = __ATTR_RO(_name)
1600 #define VMBUS_CHAN_ATTR_WO(_name) \
1601         struct vmbus_chan_attribute chan_attr_##_name = __ATTR_WO(_name)
1602
1603 static ssize_t vmbus_chan_attr_show(struct kobject *kobj,
1604                                     struct attribute *attr, char *buf)
1605 {
1606         const struct vmbus_chan_attribute *attribute
1607                 = container_of(attr, struct vmbus_chan_attribute, attr);
1608         struct vmbus_channel *chan
1609                 = container_of(kobj, struct vmbus_channel, kobj);
1610
1611         if (!attribute->show)
1612                 return -EIO;
1613
1614         return attribute->show(chan, buf);
1615 }
1616
1617 static ssize_t vmbus_chan_attr_store(struct kobject *kobj,
1618                                      struct attribute *attr, const char *buf,
1619                                      size_t count)
1620 {
1621         const struct vmbus_chan_attribute *attribute
1622                 = container_of(attr, struct vmbus_chan_attribute, attr);
1623         struct vmbus_channel *chan
1624                 = container_of(kobj, struct vmbus_channel, kobj);
1625
1626         if (!attribute->store)
1627                 return -EIO;
1628
1629         return attribute->store(chan, buf, count);
1630 }
1631
1632 static const struct sysfs_ops vmbus_chan_sysfs_ops = {
1633         .show = vmbus_chan_attr_show,
1634         .store = vmbus_chan_attr_store,
1635 };
1636
1637 static ssize_t out_mask_show(struct vmbus_channel *channel, char *buf)
1638 {
1639         struct hv_ring_buffer_info *rbi = &channel->outbound;
1640         ssize_t ret;
1641
1642         mutex_lock(&rbi->ring_buffer_mutex);
1643         if (!rbi->ring_buffer) {
1644                 mutex_unlock(&rbi->ring_buffer_mutex);
1645                 return -EINVAL;
1646         }
1647
1648         ret = sprintf(buf, "%u\n", rbi->ring_buffer->interrupt_mask);
1649         mutex_unlock(&rbi->ring_buffer_mutex);
1650         return ret;
1651 }
1652 static VMBUS_CHAN_ATTR_RO(out_mask);
1653
1654 static ssize_t in_mask_show(struct vmbus_channel *channel, char *buf)
1655 {
1656         struct hv_ring_buffer_info *rbi = &channel->inbound;
1657         ssize_t ret;
1658
1659         mutex_lock(&rbi->ring_buffer_mutex);
1660         if (!rbi->ring_buffer) {
1661                 mutex_unlock(&rbi->ring_buffer_mutex);
1662                 return -EINVAL;
1663         }
1664
1665         ret = sprintf(buf, "%u\n", rbi->ring_buffer->interrupt_mask);
1666         mutex_unlock(&rbi->ring_buffer_mutex);
1667         return ret;
1668 }
1669 static VMBUS_CHAN_ATTR_RO(in_mask);
1670
1671 static ssize_t read_avail_show(struct vmbus_channel *channel, char *buf)
1672 {
1673         struct hv_ring_buffer_info *rbi = &channel->inbound;
1674         ssize_t ret;
1675
1676         mutex_lock(&rbi->ring_buffer_mutex);
1677         if (!rbi->ring_buffer) {
1678                 mutex_unlock(&rbi->ring_buffer_mutex);
1679                 return -EINVAL;
1680         }
1681
1682         ret = sprintf(buf, "%u\n", hv_get_bytes_to_read(rbi));
1683         mutex_unlock(&rbi->ring_buffer_mutex);
1684         return ret;
1685 }
1686 static VMBUS_CHAN_ATTR_RO(read_avail);
1687
1688 static ssize_t write_avail_show(struct vmbus_channel *channel, char *buf)
1689 {
1690         struct hv_ring_buffer_info *rbi = &channel->outbound;
1691         ssize_t ret;
1692
1693         mutex_lock(&rbi->ring_buffer_mutex);
1694         if (!rbi->ring_buffer) {
1695                 mutex_unlock(&rbi->ring_buffer_mutex);
1696                 return -EINVAL;
1697         }
1698
1699         ret = sprintf(buf, "%u\n", hv_get_bytes_to_write(rbi));
1700         mutex_unlock(&rbi->ring_buffer_mutex);
1701         return ret;
1702 }
1703 static VMBUS_CHAN_ATTR_RO(write_avail);
1704
1705 static ssize_t target_cpu_show(struct vmbus_channel *channel, char *buf)
1706 {
1707         return sprintf(buf, "%u\n", channel->target_cpu);
1708 }
1709 static ssize_t target_cpu_store(struct vmbus_channel *channel,
1710                                 const char *buf, size_t count)
1711 {
1712         u32 target_cpu, origin_cpu;
1713         ssize_t ret = count;
1714
1715         if (vmbus_proto_version < VERSION_WIN10_V4_1)
1716                 return -EIO;
1717
1718         if (sscanf(buf, "%uu", &target_cpu) != 1)
1719                 return -EIO;
1720
1721         /* Validate target_cpu for the cpumask_test_cpu() operation below. */
1722         if (target_cpu >= nr_cpumask_bits)
1723                 return -EINVAL;
1724
1725         /* No CPUs should come up or down during this. */
1726         cpus_read_lock();
1727
1728         if (!cpu_online(target_cpu)) {
1729                 cpus_read_unlock();
1730                 return -EINVAL;
1731         }
1732
1733         /*
1734          * Synchronizes target_cpu_store() and channel closure:
1735          *
1736          * { Initially: state = CHANNEL_OPENED }
1737          *
1738          * CPU1                         CPU2
1739          *
1740          * [target_cpu_store()]         [vmbus_disconnect_ring()]
1741          *
1742          * LOCK channel_mutex           LOCK channel_mutex
1743          * LOAD r1 = state              LOAD r2 = state
1744          * IF (r1 == CHANNEL_OPENED)    IF (r2 == CHANNEL_OPENED)
1745          *   SEND MODIFYCHANNEL           STORE state = CHANNEL_OPEN
1746          *   [...]                        SEND CLOSECHANNEL
1747          * UNLOCK channel_mutex         UNLOCK channel_mutex
1748          *
1749          * Forbids: r1 == r2 == CHANNEL_OPENED (i.e., CPU1's LOCK precedes
1750          *              CPU2's LOCK) && CPU2's SEND precedes CPU1's SEND
1751          *
1752          * Note.  The host processes the channel messages "sequentially", in
1753          * the order in which they are received on a per-partition basis.
1754          */
1755         mutex_lock(&vmbus_connection.channel_mutex);
1756
1757         /*
1758          * Hyper-V will ignore MODIFYCHANNEL messages for "non-open" channels;
1759          * avoid sending the message and fail here for such channels.
1760          */
1761         if (channel->state != CHANNEL_OPENED_STATE) {
1762                 ret = -EIO;
1763                 goto cpu_store_unlock;
1764         }
1765
1766         origin_cpu = channel->target_cpu;
1767         if (target_cpu == origin_cpu)
1768                 goto cpu_store_unlock;
1769
1770         if (vmbus_send_modifychannel(channel->offermsg.child_relid,
1771                                      hv_cpu_number_to_vp_number(target_cpu))) {
1772                 ret = -EIO;
1773                 goto cpu_store_unlock;
1774         }
1775
1776         /*
1777          * Warning.  At this point, there is *no* guarantee that the host will
1778          * have successfully processed the vmbus_send_modifychannel() request.
1779          * See the header comment of vmbus_send_modifychannel() for more info.
1780          *
1781          * Lags in the processing of the above vmbus_send_modifychannel() can
1782          * result in missed interrupts if the "old" target CPU is taken offline
1783          * before Hyper-V starts sending interrupts to the "new" target CPU.
1784          * But apart from this offlining scenario, the code tolerates such
1785          * lags.  It will function correctly even if a channel interrupt comes
1786          * in on a CPU that is different from the channel target_cpu value.
1787          */
1788
1789         channel->target_cpu = target_cpu;
1790
1791         /* See init_vp_index(). */
1792         if (hv_is_perf_channel(channel))
1793                 hv_update_alloced_cpus(origin_cpu, target_cpu);
1794
1795         /* Currently set only for storvsc channels. */
1796         if (channel->change_target_cpu_callback) {
1797                 (*channel->change_target_cpu_callback)(channel,
1798                                 origin_cpu, target_cpu);
1799         }
1800
1801 cpu_store_unlock:
1802         mutex_unlock(&vmbus_connection.channel_mutex);
1803         cpus_read_unlock();
1804         return ret;
1805 }
1806 static VMBUS_CHAN_ATTR(cpu, 0644, target_cpu_show, target_cpu_store);
1807
1808 static ssize_t channel_pending_show(struct vmbus_channel *channel,
1809                                     char *buf)
1810 {
1811         return sprintf(buf, "%d\n",
1812                        channel_pending(channel,
1813                                        vmbus_connection.monitor_pages[1]));
1814 }
1815 static VMBUS_CHAN_ATTR(pending, S_IRUGO, channel_pending_show, NULL);
1816
1817 static ssize_t channel_latency_show(struct vmbus_channel *channel,
1818                                     char *buf)
1819 {
1820         return sprintf(buf, "%d\n",
1821                        channel_latency(channel,
1822                                        vmbus_connection.monitor_pages[1]));
1823 }
1824 static VMBUS_CHAN_ATTR(latency, S_IRUGO, channel_latency_show, NULL);
1825
1826 static ssize_t channel_interrupts_show(struct vmbus_channel *channel, char *buf)
1827 {
1828         return sprintf(buf, "%llu\n", channel->interrupts);
1829 }
1830 static VMBUS_CHAN_ATTR(interrupts, S_IRUGO, channel_interrupts_show, NULL);
1831
1832 static ssize_t channel_events_show(struct vmbus_channel *channel, char *buf)
1833 {
1834         return sprintf(buf, "%llu\n", channel->sig_events);
1835 }
1836 static VMBUS_CHAN_ATTR(events, S_IRUGO, channel_events_show, NULL);
1837
1838 static ssize_t channel_intr_in_full_show(struct vmbus_channel *channel,
1839                                          char *buf)
1840 {
1841         return sprintf(buf, "%llu\n",
1842                        (unsigned long long)channel->intr_in_full);
1843 }
1844 static VMBUS_CHAN_ATTR(intr_in_full, 0444, channel_intr_in_full_show, NULL);
1845
1846 static ssize_t channel_intr_out_empty_show(struct vmbus_channel *channel,
1847                                            char *buf)
1848 {
1849         return sprintf(buf, "%llu\n",
1850                        (unsigned long long)channel->intr_out_empty);
1851 }
1852 static VMBUS_CHAN_ATTR(intr_out_empty, 0444, channel_intr_out_empty_show, NULL);
1853
1854 static ssize_t channel_out_full_first_show(struct vmbus_channel *channel,
1855                                            char *buf)
1856 {
1857         return sprintf(buf, "%llu\n",
1858                        (unsigned long long)channel->out_full_first);
1859 }
1860 static VMBUS_CHAN_ATTR(out_full_first, 0444, channel_out_full_first_show, NULL);
1861
1862 static ssize_t channel_out_full_total_show(struct vmbus_channel *channel,
1863                                            char *buf)
1864 {
1865         return sprintf(buf, "%llu\n",
1866                        (unsigned long long)channel->out_full_total);
1867 }
1868 static VMBUS_CHAN_ATTR(out_full_total, 0444, channel_out_full_total_show, NULL);
1869
1870 static ssize_t subchannel_monitor_id_show(struct vmbus_channel *channel,
1871                                           char *buf)
1872 {
1873         return sprintf(buf, "%u\n", channel->offermsg.monitorid);
1874 }
1875 static VMBUS_CHAN_ATTR(monitor_id, S_IRUGO, subchannel_monitor_id_show, NULL);
1876
1877 static ssize_t subchannel_id_show(struct vmbus_channel *channel,
1878                                   char *buf)
1879 {
1880         return sprintf(buf, "%u\n",
1881                        channel->offermsg.offer.sub_channel_index);
1882 }
1883 static VMBUS_CHAN_ATTR_RO(subchannel_id);
1884
1885 static struct attribute *vmbus_chan_attrs[] = {
1886         &chan_attr_out_mask.attr,
1887         &chan_attr_in_mask.attr,
1888         &chan_attr_read_avail.attr,
1889         &chan_attr_write_avail.attr,
1890         &chan_attr_cpu.attr,
1891         &chan_attr_pending.attr,
1892         &chan_attr_latency.attr,
1893         &chan_attr_interrupts.attr,
1894         &chan_attr_events.attr,
1895         &chan_attr_intr_in_full.attr,
1896         &chan_attr_intr_out_empty.attr,
1897         &chan_attr_out_full_first.attr,
1898         &chan_attr_out_full_total.attr,
1899         &chan_attr_monitor_id.attr,
1900         &chan_attr_subchannel_id.attr,
1901         NULL
1902 };
1903
1904 /*
1905  * Channel-level attribute_group callback function. Returns the permission for
1906  * each attribute, and returns 0 if an attribute is not visible.
1907  */
1908 static umode_t vmbus_chan_attr_is_visible(struct kobject *kobj,
1909                                           struct attribute *attr, int idx)
1910 {
1911         const struct vmbus_channel *channel =
1912                 container_of(kobj, struct vmbus_channel, kobj);
1913
1914         /* Hide the monitor attributes if the monitor mechanism is not used. */
1915         if (!channel->offermsg.monitor_allocated &&
1916             (attr == &chan_attr_pending.attr ||
1917              attr == &chan_attr_latency.attr ||
1918              attr == &chan_attr_monitor_id.attr))
1919                 return 0;
1920
1921         return attr->mode;
1922 }
1923
1924 static struct attribute_group vmbus_chan_group = {
1925         .attrs = vmbus_chan_attrs,
1926         .is_visible = vmbus_chan_attr_is_visible
1927 };
1928
1929 static struct kobj_type vmbus_chan_ktype = {
1930         .sysfs_ops = &vmbus_chan_sysfs_ops,
1931         .release = vmbus_chan_release,
1932 };
1933
1934 /*
1935  * vmbus_add_channel_kobj - setup a sub-directory under device/channels
1936  */
1937 int vmbus_add_channel_kobj(struct hv_device *dev, struct vmbus_channel *channel)
1938 {
1939         const struct device *device = &dev->device;
1940         struct kobject *kobj = &channel->kobj;
1941         u32 relid = channel->offermsg.child_relid;
1942         int ret;
1943
1944         kobj->kset = dev->channels_kset;
1945         ret = kobject_init_and_add(kobj, &vmbus_chan_ktype, NULL,
1946                                    "%u", relid);
1947         if (ret)
1948                 return ret;
1949
1950         ret = sysfs_create_group(kobj, &vmbus_chan_group);
1951
1952         if (ret) {
1953                 /*
1954                  * The calling functions' error handling paths will cleanup the
1955                  * empty channel directory.
1956                  */
1957                 dev_err(device, "Unable to set up channel sysfs files\n");
1958                 return ret;
1959         }
1960
1961         kobject_uevent(kobj, KOBJ_ADD);
1962
1963         return 0;
1964 }
1965
1966 /*
1967  * vmbus_remove_channel_attr_group - remove the channel's attribute group
1968  */
1969 void vmbus_remove_channel_attr_group(struct vmbus_channel *channel)
1970 {
1971         sysfs_remove_group(&channel->kobj, &vmbus_chan_group);
1972 }
1973
1974 /*
1975  * vmbus_device_create - Creates and registers a new child device
1976  * on the vmbus.
1977  */
1978 struct hv_device *vmbus_device_create(const guid_t *type,
1979                                       const guid_t *instance,
1980                                       struct vmbus_channel *channel)
1981 {
1982         struct hv_device *child_device_obj;
1983
1984         child_device_obj = kzalloc(sizeof(struct hv_device), GFP_KERNEL);
1985         if (!child_device_obj) {
1986                 pr_err("Unable to allocate device object for child device\n");
1987                 return NULL;
1988         }
1989
1990         child_device_obj->channel = channel;
1991         guid_copy(&child_device_obj->dev_type, type);
1992         guid_copy(&child_device_obj->dev_instance, instance);
1993         child_device_obj->vendor_id = 0x1414; /* MSFT vendor ID */
1994
1995         return child_device_obj;
1996 }
1997
1998 /*
1999  * vmbus_device_register - Register the child device
2000  */
2001 int vmbus_device_register(struct hv_device *child_device_obj)
2002 {
2003         struct kobject *kobj = &child_device_obj->device.kobj;
2004         int ret;
2005
2006         dev_set_name(&child_device_obj->device, "%pUl",
2007                      &child_device_obj->channel->offermsg.offer.if_instance);
2008
2009         child_device_obj->device.bus = &hv_bus;
2010         child_device_obj->device.parent = &hv_acpi_dev->dev;
2011         child_device_obj->device.release = vmbus_device_release;
2012
2013         /*
2014          * Register with the LDM. This will kick off the driver/device
2015          * binding...which will eventually call vmbus_match() and vmbus_probe()
2016          */
2017         ret = device_register(&child_device_obj->device);
2018         if (ret) {
2019                 pr_err("Unable to register child device\n");
2020                 return ret;
2021         }
2022
2023         child_device_obj->channels_kset = kset_create_and_add("channels",
2024                                                               NULL, kobj);
2025         if (!child_device_obj->channels_kset) {
2026                 ret = -ENOMEM;
2027                 goto err_dev_unregister;
2028         }
2029
2030         ret = vmbus_add_channel_kobj(child_device_obj,
2031                                      child_device_obj->channel);
2032         if (ret) {
2033                 pr_err("Unable to register primary channeln");
2034                 goto err_kset_unregister;
2035         }
2036         hv_debug_add_dev_dir(child_device_obj);
2037
2038         return 0;
2039
2040 err_kset_unregister:
2041         kset_unregister(child_device_obj->channels_kset);
2042
2043 err_dev_unregister:
2044         device_unregister(&child_device_obj->device);
2045         return ret;
2046 }
2047
2048 /*
2049  * vmbus_device_unregister - Remove the specified child device
2050  * from the vmbus.
2051  */
2052 void vmbus_device_unregister(struct hv_device *device_obj)
2053 {
2054         pr_debug("child device %s unregistered\n",
2055                 dev_name(&device_obj->device));
2056
2057         kset_unregister(device_obj->channels_kset);
2058
2059         /*
2060          * Kick off the process of unregistering the device.
2061          * This will call vmbus_remove() and eventually vmbus_device_release()
2062          */
2063         device_unregister(&device_obj->device);
2064 }
2065
2066
2067 /*
2068  * VMBUS is an acpi enumerated device. Get the information we
2069  * need from DSDT.
2070  */
2071 #define VTPM_BASE_ADDRESS 0xfed40000
2072 static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *ctx)
2073 {
2074         resource_size_t start = 0;
2075         resource_size_t end = 0;
2076         struct resource *new_res;
2077         struct resource **old_res = &hyperv_mmio;
2078         struct resource **prev_res = NULL;
2079         struct resource r;
2080
2081         switch (res->type) {
2082
2083         /*
2084          * "Address" descriptors are for bus windows. Ignore
2085          * "memory" descriptors, which are for registers on
2086          * devices.
2087          */
2088         case ACPI_RESOURCE_TYPE_ADDRESS32:
2089                 start = res->data.address32.address.minimum;
2090                 end = res->data.address32.address.maximum;
2091                 break;
2092
2093         case ACPI_RESOURCE_TYPE_ADDRESS64:
2094                 start = res->data.address64.address.minimum;
2095                 end = res->data.address64.address.maximum;
2096                 break;
2097
2098         /*
2099          * The IRQ information is needed only on ARM64, which Hyper-V
2100          * sets up in the extended format. IRQ information is present
2101          * on x86/x64 in the non-extended format but it is not used by
2102          * Linux. So don't bother checking for the non-extended format.
2103          */
2104         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
2105                 if (!acpi_dev_resource_interrupt(res, 0, &r)) {
2106                         pr_err("Unable to parse Hyper-V ACPI interrupt\n");
2107                         return AE_ERROR;
2108                 }
2109                 /* ARM64 INTID for VMbus */
2110                 vmbus_interrupt = res->data.extended_irq.interrupts[0];
2111                 /* Linux IRQ number */
2112                 vmbus_irq = r.start;
2113                 return AE_OK;
2114
2115         default:
2116                 /* Unused resource type */
2117                 return AE_OK;
2118
2119         }
2120         /*
2121          * Ignore ranges that are below 1MB, as they're not
2122          * necessary or useful here.
2123          */
2124         if (end < 0x100000)
2125                 return AE_OK;
2126
2127         new_res = kzalloc(sizeof(*new_res), GFP_ATOMIC);
2128         if (!new_res)
2129                 return AE_NO_MEMORY;
2130
2131         /* If this range overlaps the virtual TPM, truncate it. */
2132         if (end > VTPM_BASE_ADDRESS && start < VTPM_BASE_ADDRESS)
2133                 end = VTPM_BASE_ADDRESS;
2134
2135         new_res->name = "hyperv mmio";
2136         new_res->flags = IORESOURCE_MEM;
2137         new_res->start = start;
2138         new_res->end = end;
2139
2140         /*
2141          * If two ranges are adjacent, merge them.
2142          */
2143         do {
2144                 if (!*old_res) {
2145                         *old_res = new_res;
2146                         break;
2147                 }
2148
2149                 if (((*old_res)->end + 1) == new_res->start) {
2150                         (*old_res)->end = new_res->end;
2151                         kfree(new_res);
2152                         break;
2153                 }
2154
2155                 if ((*old_res)->start == new_res->end + 1) {
2156                         (*old_res)->start = new_res->start;
2157                         kfree(new_res);
2158                         break;
2159                 }
2160
2161                 if ((*old_res)->start > new_res->end) {
2162                         new_res->sibling = *old_res;
2163                         if (prev_res)
2164                                 (*prev_res)->sibling = new_res;
2165                         *old_res = new_res;
2166                         break;
2167                 }
2168
2169                 prev_res = old_res;
2170                 old_res = &(*old_res)->sibling;
2171
2172         } while (1);
2173
2174         return AE_OK;
2175 }
2176
2177 static int vmbus_acpi_remove(struct acpi_device *device)
2178 {
2179         struct resource *cur_res;
2180         struct resource *next_res;
2181
2182         if (hyperv_mmio) {
2183                 if (fb_mmio) {
2184                         __release_region(hyperv_mmio, fb_mmio->start,
2185                                          resource_size(fb_mmio));
2186                         fb_mmio = NULL;
2187                 }
2188
2189                 for (cur_res = hyperv_mmio; cur_res; cur_res = next_res) {
2190                         next_res = cur_res->sibling;
2191                         kfree(cur_res);
2192                 }
2193         }
2194
2195         return 0;
2196 }
2197
2198 static void vmbus_reserve_fb(void)
2199 {
2200         int size;
2201         /*
2202          * Make a claim for the frame buffer in the resource tree under the
2203          * first node, which will be the one below 4GB.  The length seems to
2204          * be underreported, particularly in a Generation 1 VM.  So start out
2205          * reserving a larger area and make it smaller until it succeeds.
2206          */
2207
2208         if (screen_info.lfb_base) {
2209                 if (efi_enabled(EFI_BOOT))
2210                         size = max_t(__u32, screen_info.lfb_size, 0x800000);
2211                 else
2212                         size = max_t(__u32, screen_info.lfb_size, 0x4000000);
2213
2214                 for (; !fb_mmio && (size >= 0x100000); size >>= 1) {
2215                         fb_mmio = __request_region(hyperv_mmio,
2216                                                    screen_info.lfb_base, size,
2217                                                    fb_mmio_name, 0);
2218                 }
2219         }
2220 }
2221
2222 /**
2223  * vmbus_allocate_mmio() - Pick a memory-mapped I/O range.
2224  * @new:                If successful, supplied a pointer to the
2225  *                      allocated MMIO space.
2226  * @device_obj:         Identifies the caller
2227  * @min:                Minimum guest physical address of the
2228  *                      allocation
2229  * @max:                Maximum guest physical address
2230  * @size:               Size of the range to be allocated
2231  * @align:              Alignment of the range to be allocated
2232  * @fb_overlap_ok:      Whether this allocation can be allowed
2233  *                      to overlap the video frame buffer.
2234  *
2235  * This function walks the resources granted to VMBus by the
2236  * _CRS object in the ACPI namespace underneath the parent
2237  * "bridge" whether that's a root PCI bus in the Generation 1
2238  * case or a Module Device in the Generation 2 case.  It then
2239  * attempts to allocate from the global MMIO pool in a way that
2240  * matches the constraints supplied in these parameters and by
2241  * that _CRS.
2242  *
2243  * Return: 0 on success, -errno on failure
2244  */
2245 int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
2246                         resource_size_t min, resource_size_t max,
2247                         resource_size_t size, resource_size_t align,
2248                         bool fb_overlap_ok)
2249 {
2250         struct resource *iter, *shadow;
2251         resource_size_t range_min, range_max, start;
2252         const char *dev_n = dev_name(&device_obj->device);
2253         int retval;
2254
2255         retval = -ENXIO;
2256         mutex_lock(&hyperv_mmio_lock);
2257
2258         /*
2259          * If overlaps with frame buffers are allowed, then first attempt to
2260          * make the allocation from within the reserved region.  Because it
2261          * is already reserved, no shadow allocation is necessary.
2262          */
2263         if (fb_overlap_ok && fb_mmio && !(min > fb_mmio->end) &&
2264             !(max < fb_mmio->start)) {
2265
2266                 range_min = fb_mmio->start;
2267                 range_max = fb_mmio->end;
2268                 start = (range_min + align - 1) & ~(align - 1);
2269                 for (; start + size - 1 <= range_max; start += align) {
2270                         *new = request_mem_region_exclusive(start, size, dev_n);
2271                         if (*new) {
2272                                 retval = 0;
2273                                 goto exit;
2274                         }
2275                 }
2276         }
2277
2278         for (iter = hyperv_mmio; iter; iter = iter->sibling) {
2279                 if ((iter->start >= max) || (iter->end <= min))
2280                         continue;
2281
2282                 range_min = iter->start;
2283                 range_max = iter->end;
2284                 start = (range_min + align - 1) & ~(align - 1);
2285                 for (; start + size - 1 <= range_max; start += align) {
2286                         shadow = __request_region(iter, start, size, NULL,
2287                                                   IORESOURCE_BUSY);
2288                         if (!shadow)
2289                                 continue;
2290
2291                         *new = request_mem_region_exclusive(start, size, dev_n);
2292                         if (*new) {
2293                                 shadow->name = (char *)*new;
2294                                 retval = 0;
2295                                 goto exit;
2296                         }
2297
2298                         __release_region(iter, start, size);
2299                 }
2300         }
2301
2302 exit:
2303         mutex_unlock(&hyperv_mmio_lock);
2304         return retval;
2305 }
2306 EXPORT_SYMBOL_GPL(vmbus_allocate_mmio);
2307
2308 /**
2309  * vmbus_free_mmio() - Free a memory-mapped I/O range.
2310  * @start:              Base address of region to release.
2311  * @size:               Size of the range to be allocated
2312  *
2313  * This function releases anything requested by
2314  * vmbus_mmio_allocate().
2315  */
2316 void vmbus_free_mmio(resource_size_t start, resource_size_t size)
2317 {
2318         struct resource *iter;
2319
2320         mutex_lock(&hyperv_mmio_lock);
2321         for (iter = hyperv_mmio; iter; iter = iter->sibling) {
2322                 if ((iter->start >= start + size) || (iter->end <= start))
2323                         continue;
2324
2325                 __release_region(iter, start, size);
2326         }
2327         release_mem_region(start, size);
2328         mutex_unlock(&hyperv_mmio_lock);
2329
2330 }
2331 EXPORT_SYMBOL_GPL(vmbus_free_mmio);
2332
2333 static int vmbus_acpi_add(struct acpi_device *device)
2334 {
2335         acpi_status result;
2336         int ret_val = -ENODEV;
2337         struct acpi_device *ancestor;
2338
2339         hv_acpi_dev = device;
2340
2341         result = acpi_walk_resources(device->handle, METHOD_NAME__CRS,
2342                                         vmbus_walk_resources, NULL);
2343
2344         if (ACPI_FAILURE(result))
2345                 goto acpi_walk_err;
2346         /*
2347          * Some ancestor of the vmbus acpi device (Gen1 or Gen2
2348          * firmware) is the VMOD that has the mmio ranges. Get that.
2349          */
2350         for (ancestor = device->parent; ancestor; ancestor = ancestor->parent) {
2351                 result = acpi_walk_resources(ancestor->handle, METHOD_NAME__CRS,
2352                                              vmbus_walk_resources, NULL);
2353
2354                 if (ACPI_FAILURE(result))
2355                         continue;
2356                 if (hyperv_mmio) {
2357                         vmbus_reserve_fb();
2358                         break;
2359                 }
2360         }
2361         ret_val = 0;
2362
2363 acpi_walk_err:
2364         complete(&probe_event);
2365         if (ret_val)
2366                 vmbus_acpi_remove(device);
2367         return ret_val;
2368 }
2369
2370 #ifdef CONFIG_PM_SLEEP
2371 static int vmbus_bus_suspend(struct device *dev)
2372 {
2373         struct vmbus_channel *channel, *sc;
2374
2375         while (atomic_read(&vmbus_connection.offer_in_progress) != 0) {
2376                 /*
2377                  * We wait here until the completion of any channel
2378                  * offers that are currently in progress.
2379                  */
2380                 msleep(1);
2381         }
2382
2383         mutex_lock(&vmbus_connection.channel_mutex);
2384         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
2385                 if (!is_hvsock_channel(channel))
2386                         continue;
2387
2388                 vmbus_force_channel_rescinded(channel);
2389         }
2390         mutex_unlock(&vmbus_connection.channel_mutex);
2391
2392         /*
2393          * Wait until all the sub-channels and hv_sock channels have been
2394          * cleaned up. Sub-channels should be destroyed upon suspend, otherwise
2395          * they would conflict with the new sub-channels that will be created
2396          * in the resume path. hv_sock channels should also be destroyed, but
2397          * a hv_sock channel of an established hv_sock connection can not be
2398          * really destroyed since it may still be referenced by the userspace
2399          * application, so we just force the hv_sock channel to be rescinded
2400          * by vmbus_force_channel_rescinded(), and the userspace application
2401          * will thoroughly destroy the channel after hibernation.
2402          *
2403          * Note: the counter nr_chan_close_on_suspend may never go above 0 if
2404          * the VM has no sub-channel and hv_sock channel, e.g. a 1-vCPU VM.
2405          */
2406         if (atomic_read(&vmbus_connection.nr_chan_close_on_suspend) > 0)
2407                 wait_for_completion(&vmbus_connection.ready_for_suspend_event);
2408
2409         if (atomic_read(&vmbus_connection.nr_chan_fixup_on_resume) != 0) {
2410                 pr_err("Can not suspend due to a previous failed resuming\n");
2411                 return -EBUSY;
2412         }
2413
2414         mutex_lock(&vmbus_connection.channel_mutex);
2415
2416         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
2417                 /*
2418                  * Remove the channel from the array of channels and invalidate
2419                  * the channel's relid.  Upon resume, vmbus_onoffer() will fix
2420                  * up the relid (and other fields, if necessary) and add the
2421                  * channel back to the array.
2422                  */
2423                 vmbus_channel_unmap_relid(channel);
2424                 channel->offermsg.child_relid = INVALID_RELID;
2425
2426                 if (is_hvsock_channel(channel)) {
2427                         if (!channel->rescind) {
2428                                 pr_err("hv_sock channel not rescinded!\n");
2429                                 WARN_ON_ONCE(1);
2430                         }
2431                         continue;
2432                 }
2433
2434                 list_for_each_entry(sc, &channel->sc_list, sc_list) {
2435                         pr_err("Sub-channel not deleted!\n");
2436                         WARN_ON_ONCE(1);
2437                 }
2438
2439                 atomic_inc(&vmbus_connection.nr_chan_fixup_on_resume);
2440         }
2441
2442         mutex_unlock(&vmbus_connection.channel_mutex);
2443
2444         vmbus_initiate_unload(false);
2445
2446         /* Reset the event for the next resume. */
2447         reinit_completion(&vmbus_connection.ready_for_resume_event);
2448
2449         return 0;
2450 }
2451
2452 static int vmbus_bus_resume(struct device *dev)
2453 {
2454         struct vmbus_channel_msginfo *msginfo;
2455         size_t msgsize;
2456         int ret;
2457
2458         /*
2459          * We only use the 'vmbus_proto_version', which was in use before
2460          * hibernation, to re-negotiate with the host.
2461          */
2462         if (!vmbus_proto_version) {
2463                 pr_err("Invalid proto version = 0x%x\n", vmbus_proto_version);
2464                 return -EINVAL;
2465         }
2466
2467         msgsize = sizeof(*msginfo) +
2468                   sizeof(struct vmbus_channel_initiate_contact);
2469
2470         msginfo = kzalloc(msgsize, GFP_KERNEL);
2471
2472         if (msginfo == NULL)
2473                 return -ENOMEM;
2474
2475         ret = vmbus_negotiate_version(msginfo, vmbus_proto_version);
2476
2477         kfree(msginfo);
2478
2479         if (ret != 0)
2480                 return ret;
2481
2482         WARN_ON(atomic_read(&vmbus_connection.nr_chan_fixup_on_resume) == 0);
2483
2484         vmbus_request_offers();
2485
2486         if (wait_for_completion_timeout(
2487                 &vmbus_connection.ready_for_resume_event, 10 * HZ) == 0)
2488                 pr_err("Some vmbus device is missing after suspending?\n");
2489
2490         /* Reset the event for the next suspend. */
2491         reinit_completion(&vmbus_connection.ready_for_suspend_event);
2492
2493         return 0;
2494 }
2495 #else
2496 #define vmbus_bus_suspend NULL
2497 #define vmbus_bus_resume NULL
2498 #endif /* CONFIG_PM_SLEEP */
2499
2500 static const struct acpi_device_id vmbus_acpi_device_ids[] = {
2501         {"VMBUS", 0},
2502         {"VMBus", 0},
2503         {"", 0},
2504 };
2505 MODULE_DEVICE_TABLE(acpi, vmbus_acpi_device_ids);
2506
2507 /*
2508  * Note: we must use the "no_irq" ops, otherwise hibernation can not work with
2509  * PCI device assignment, because "pci_dev_pm_ops" uses the "noirq" ops: in
2510  * the resume path, the pci "noirq" restore op runs before "non-noirq" op (see
2511  * resume_target_kernel() -> dpm_resume_start(), and hibernation_restore() ->
2512  * dpm_resume_end()). This means vmbus_bus_resume() and the pci-hyperv's
2513  * resume callback must also run via the "noirq" ops.
2514  *
2515  * Set suspend_noirq/resume_noirq to NULL for Suspend-to-Idle: see the comment
2516  * earlier in this file before vmbus_pm.
2517  */
2518
2519 static const struct dev_pm_ops vmbus_bus_pm = {
2520         .suspend_noirq  = NULL,
2521         .resume_noirq   = NULL,
2522         .freeze_noirq   = vmbus_bus_suspend,
2523         .thaw_noirq     = vmbus_bus_resume,
2524         .poweroff_noirq = vmbus_bus_suspend,
2525         .restore_noirq  = vmbus_bus_resume
2526 };
2527
2528 static struct acpi_driver vmbus_acpi_driver = {
2529         .name = "vmbus",
2530         .ids = vmbus_acpi_device_ids,
2531         .ops = {
2532                 .add = vmbus_acpi_add,
2533                 .remove = vmbus_acpi_remove,
2534         },
2535         .drv.pm = &vmbus_bus_pm,
2536 };
2537
2538 static void hv_kexec_handler(void)
2539 {
2540         hv_stimer_global_cleanup();
2541         vmbus_initiate_unload(false);
2542         /* Make sure conn_state is set as hv_synic_cleanup checks for it */
2543         mb();
2544         cpuhp_remove_state(hyperv_cpuhp_online);
2545         hyperv_cleanup();
2546 };
2547
2548 static void hv_crash_handler(struct pt_regs *regs)
2549 {
2550         int cpu;
2551
2552         vmbus_initiate_unload(true);
2553         /*
2554          * In crash handler we can't schedule synic cleanup for all CPUs,
2555          * doing the cleanup for current CPU only. This should be sufficient
2556          * for kdump.
2557          */
2558         cpu = smp_processor_id();
2559         hv_stimer_cleanup(cpu);
2560         hv_synic_disable_regs(cpu);
2561         hyperv_cleanup();
2562 };
2563
2564 static int hv_synic_suspend(void)
2565 {
2566         /*
2567          * When we reach here, all the non-boot CPUs have been offlined.
2568          * If we're in a legacy configuration where stimer Direct Mode is
2569          * not enabled, the stimers on the non-boot CPUs have been unbound
2570          * in hv_synic_cleanup() -> hv_stimer_legacy_cleanup() ->
2571          * hv_stimer_cleanup() -> clockevents_unbind_device().
2572          *
2573          * hv_synic_suspend() only runs on CPU0 with interrupts disabled.
2574          * Here we do not call hv_stimer_legacy_cleanup() on CPU0 because:
2575          * 1) it's unnecessary as interrupts remain disabled between
2576          * syscore_suspend() and syscore_resume(): see create_image() and
2577          * resume_target_kernel()
2578          * 2) the stimer on CPU0 is automatically disabled later by
2579          * syscore_suspend() -> timekeeping_suspend() -> tick_suspend() -> ...
2580          * -> clockevents_shutdown() -> ... -> hv_ce_shutdown()
2581          * 3) a warning would be triggered if we call
2582          * clockevents_unbind_device(), which may sleep, in an
2583          * interrupts-disabled context.
2584          */
2585
2586         hv_synic_disable_regs(0);
2587
2588         return 0;
2589 }
2590
2591 static void hv_synic_resume(void)
2592 {
2593         hv_synic_enable_regs(0);
2594
2595         /*
2596          * Note: we don't need to call hv_stimer_init(0), because the timer
2597          * on CPU0 is not unbound in hv_synic_suspend(), and the timer is
2598          * automatically re-enabled in timekeeping_resume().
2599          */
2600 }
2601
2602 /* The callbacks run only on CPU0, with irqs_disabled. */
2603 static struct syscore_ops hv_synic_syscore_ops = {
2604         .suspend = hv_synic_suspend,
2605         .resume = hv_synic_resume,
2606 };
2607
2608 static int __init hv_acpi_init(void)
2609 {
2610         int ret, t;
2611
2612         if (!hv_is_hyperv_initialized())
2613                 return -ENODEV;
2614
2615         init_completion(&probe_event);
2616
2617         /*
2618          * Get ACPI resources first.
2619          */
2620         ret = acpi_bus_register_driver(&vmbus_acpi_driver);
2621
2622         if (ret)
2623                 return ret;
2624
2625         t = wait_for_completion_timeout(&probe_event, 5*HZ);
2626         if (t == 0) {
2627                 ret = -ETIMEDOUT;
2628                 goto cleanup;
2629         }
2630         hv_debug_init();
2631
2632         ret = vmbus_bus_init();
2633         if (ret)
2634                 goto cleanup;
2635
2636         hv_setup_kexec_handler(hv_kexec_handler);
2637         hv_setup_crash_handler(hv_crash_handler);
2638
2639         register_syscore_ops(&hv_synic_syscore_ops);
2640
2641         return 0;
2642
2643 cleanup:
2644         acpi_bus_unregister_driver(&vmbus_acpi_driver);
2645         hv_acpi_dev = NULL;
2646         return ret;
2647 }
2648
2649 static void __exit vmbus_exit(void)
2650 {
2651         int cpu;
2652
2653         unregister_syscore_ops(&hv_synic_syscore_ops);
2654
2655         hv_remove_kexec_handler();
2656         hv_remove_crash_handler();
2657         vmbus_connection.conn_state = DISCONNECTED;
2658         hv_stimer_global_cleanup();
2659         vmbus_disconnect();
2660         hv_remove_vmbus_irq();
2661         for_each_online_cpu(cpu) {
2662                 struct hv_per_cpu_context *hv_cpu
2663                         = per_cpu_ptr(hv_context.cpu_context, cpu);
2664
2665                 tasklet_kill(&hv_cpu->msg_dpc);
2666         }
2667         hv_debug_rm_all_dir();
2668
2669         vmbus_free_channels();
2670         kfree(vmbus_connection.channels);
2671
2672         if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
2673                 kmsg_dump_unregister(&hv_kmsg_dumper);
2674                 unregister_die_notifier(&hyperv_die_block);
2675                 atomic_notifier_chain_unregister(&panic_notifier_list,
2676                                                  &hyperv_panic_block);
2677         }
2678
2679         free_page((unsigned long)hv_panic_page);
2680         unregister_sysctl_table(hv_ctl_table_hdr);
2681         hv_ctl_table_hdr = NULL;
2682         bus_unregister(&hv_bus);
2683
2684         cpuhp_remove_state(hyperv_cpuhp_online);
2685         hv_synic_free();
2686         acpi_bus_unregister_driver(&vmbus_acpi_driver);
2687 }
2688
2689
2690 MODULE_LICENSE("GPL");
2691 MODULE_DESCRIPTION("Microsoft Hyper-V VMBus Driver");
2692
2693 subsys_initcall(hv_acpi_init);
2694 module_exit(vmbus_exit);