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/panic_notifier.h>
  29 #include <linux/ptrace.h>
  30 #include <linux/screen_info.h>
  31 #include <linux/kdebug.h>
  32 #include <linux/efi.h>
  33 #include <linux/random.h>
  34 #include <linux/kernel.h>
  35 #include <linux/syscore_ops.h>
  36 #include <linux/dma-map-ops.h>
  37 #include <clocksource/hyperv_timer.h>
  38 #include "hyperv_vmbus.h"
  39
  40 struct vmbus_dynid {
  41         struct list_head node;
  42         struct hv_vmbus_device_id id;
  43 };
  44
  45 static struct acpi_device  *hv_acpi_dev;
  46
  47 static struct completion probe_event;
  48
  49 static int hyperv_cpuhp_online;
  50
  51 static void *hv_panic_page;
  52
  53 static long __percpu *vmbus_evt;
  54
  55 /* Values parsed from ACPI DSDT */
  56 int vmbus_irq;
  57 int vmbus_interrupt;
  58
  59 /*
  60  * Boolean to control whether to report panic messages over Hyper-V.
  61  *
  62  * It can be set via /proc/sys/kernel/hyperv_record_panic_msg
  63  */
  64 static int sysctl_record_panic_msg = 1;
  65
  66 static int hyperv_report_reg(void)
  67 {
  68         return !sysctl_record_panic_msg || !hv_panic_page;
  69 }
  70
  71 static int hyperv_panic_event(struct notifier_block *nb, unsigned long val,
  72                               void *args)
  73 {
  74         struct pt_regs *regs;
  75
  76         vmbus_initiate_unload(true);
  77
  78         /*
  79          * Hyper-V should be notified only once about a panic.  If we will be
  80          * doing hv_kmsg_dump() with kmsg data later, don't do the notification
  81          * here.
  82          */
  83         if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE
  84             && hyperv_report_reg()) {
  85                 regs = current_pt_regs();
  86                 hyperv_report_panic(regs, val, false);
  87         }
  88         return NOTIFY_DONE;
  89 }
  90
  91 static int hyperv_die_event(struct notifier_block *nb, unsigned long val,
  92                             void *args)
  93 {
  94         struct die_args *die = args;
  95         struct pt_regs *regs = die->regs;
  96
  97         /* Don't notify Hyper-V if the die event is other than oops */
  98         if (val != DIE_OOPS)
  99                 return NOTIFY_DONE;
 100
 101         /*
 102          * Hyper-V should be notified only once about a panic.  If we will be
 103          * doing hv_kmsg_dump() with kmsg data later, don't do the notification
 104          * here.
 105          */
 106         if (hyperv_report_reg())
 107                 hyperv_report_panic(regs, val, true);
 108         return NOTIFY_DONE;
 109 }
 110
 111 static struct notifier_block hyperv_die_block = {
 112         .notifier_call = hyperv_die_event,
 113 };
 114 static struct notifier_block hyperv_panic_block = {
 115         .notifier_call = hyperv_panic_event,
 116 };
 117
 118 static const char *fb_mmio_name = "fb_range";
 119 static struct resource *fb_mmio;
 120 static struct resource *hyperv_mmio;
 121 static DEFINE_MUTEX(hyperv_mmio_lock);
 122
 123 static int vmbus_exists(void)
 124 {
 125         if (hv_acpi_dev == NULL)
 126                 return -ENODEV;
 127
 128         return 0;
 129 }
 130
 131 static u8 channel_monitor_group(const struct vmbus_channel *channel)
 132 {
 133         return (u8)channel->offermsg.monitorid / 32;
 134 }
 135
 136 static u8 channel_monitor_offset(const struct vmbus_channel *channel)
 137 {
 138         return (u8)channel->offermsg.monitorid % 32;
 139 }
 140
 141 static u32 channel_pending(const struct vmbus_channel *channel,
 142                            const struct hv_monitor_page *monitor_page)
 143 {
 144         u8 monitor_group = channel_monitor_group(channel);
 145
 146         return monitor_page->trigger_group[monitor_group].pending;
 147 }
 148
 149 static u32 channel_latency(const struct vmbus_channel *channel,
 150                            const struct hv_monitor_page *monitor_page)
 151 {
 152         u8 monitor_group = channel_monitor_group(channel);
 153         u8 monitor_offset = channel_monitor_offset(channel);
 154
 155         return monitor_page->latency[monitor_group][monitor_offset];
 156 }
 157
 158 static u32 channel_conn_id(struct vmbus_channel *channel,
 159                            struct hv_monitor_page *monitor_page)
 160 {
 161         u8 monitor_group = channel_monitor_group(channel);
 162         u8 monitor_offset = channel_monitor_offset(channel);
 163
 164         return monitor_page->parameter[monitor_group][monitor_offset].connectionid.u.id;
 165 }
 166
 167 static ssize_t id_show(struct device *dev, struct device_attribute *dev_attr,
 168                        char *buf)
 169 {
 170         struct hv_device *hv_dev = device_to_hv_device(dev);
 171
 172         if (!hv_dev->channel)
 173                 return -ENODEV;
 174         return sprintf(buf, "%d\n", hv_dev->channel->offermsg.child_relid);
 175 }
 176 static DEVICE_ATTR_RO(id);
 177
 178 static ssize_t state_show(struct device *dev, struct device_attribute *dev_attr,
 179                           char *buf)
 180 {
 181         struct hv_device *hv_dev = device_to_hv_device(dev);
 182
 183         if (!hv_dev->channel)
 184                 return -ENODEV;
 185         return sprintf(buf, "%d\n", hv_dev->channel->state);
 186 }
 187 static DEVICE_ATTR_RO(state);
 188
 189 static ssize_t monitor_id_show(struct device *dev,
 190                                struct device_attribute *dev_attr, char *buf)
 191 {
 192         struct hv_device *hv_dev = device_to_hv_device(dev);
 193
 194         if (!hv_dev->channel)
 195                 return -ENODEV;
 196         return sprintf(buf, "%d\n", hv_dev->channel->offermsg.monitorid);
 197 }
 198 static DEVICE_ATTR_RO(monitor_id);
 199
 200 static ssize_t class_id_show(struct device *dev,
 201                                struct device_attribute *dev_attr, char *buf)
 202 {
 203         struct hv_device *hv_dev = device_to_hv_device(dev);
 204
 205         if (!hv_dev->channel)
 206                 return -ENODEV;
 207         return sprintf(buf, "{%pUl}\n",
 208                        &hv_dev->channel->offermsg.offer.if_type);
 209 }
 210 static DEVICE_ATTR_RO(class_id);
 211
 212 static ssize_t device_id_show(struct device *dev,
 213                               struct device_attribute *dev_attr, char *buf)
 214 {
 215         struct hv_device *hv_dev = device_to_hv_device(dev);
 216
 217         if (!hv_dev->channel)
 218                 return -ENODEV;
 219         return sprintf(buf, "{%pUl}\n",
 220                        &hv_dev->channel->offermsg.offer.if_instance);
 221 }
 222 static DEVICE_ATTR_RO(device_id);
 223
 224 static ssize_t modalias_show(struct device *dev,
 225                              struct device_attribute *dev_attr, char *buf)
 226 {
 227         struct hv_device *hv_dev = device_to_hv_device(dev);
 228
 229         return sprintf(buf, "vmbus:%*phN\n", UUID_SIZE, &hv_dev->dev_type);
 230 }
 231 static DEVICE_ATTR_RO(modalias);
 232
 233 #ifdef CONFIG_NUMA
 234 static ssize_t numa_node_show(struct device *dev,
 235                               struct device_attribute *attr, char *buf)
 236 {
 237         struct hv_device *hv_dev = device_to_hv_device(dev);
 238
 239         if (!hv_dev->channel)
 240                 return -ENODEV;
 241
 242         return sprintf(buf, "%d\n", cpu_to_node(hv_dev->channel->target_cpu));
 243 }
 244 static DEVICE_ATTR_RO(numa_node);
 245 #endif
 246
 247 static ssize_t server_monitor_pending_show(struct device *dev,
 248                                            struct device_attribute *dev_attr,
 249                                            char *buf)
 250 {
 251         struct hv_device *hv_dev = device_to_hv_device(dev);
 252
 253         if (!hv_dev->channel)
 254                 return -ENODEV;
 255         return sprintf(buf, "%d\n",
 256                        channel_pending(hv_dev->channel,
 257                                        vmbus_connection.monitor_pages[0]));
 258 }
 259 static DEVICE_ATTR_RO(server_monitor_pending);
 260
 261 static ssize_t client_monitor_pending_show(struct device *dev,
 262                                            struct device_attribute *dev_attr,
 263                                            char *buf)
 264 {
 265         struct hv_device *hv_dev = device_to_hv_device(dev);
 266
 267         if (!hv_dev->channel)
 268                 return -ENODEV;
 269         return sprintf(buf, "%d\n",
 270                        channel_pending(hv_dev->channel,
 271                                        vmbus_connection.monitor_pages[1]));
 272 }
 273 static DEVICE_ATTR_RO(client_monitor_pending);
 274
 275 static ssize_t server_monitor_latency_show(struct device *dev,
 276                                            struct device_attribute *dev_attr,
 277                                            char *buf)
 278 {
 279         struct hv_device *hv_dev = device_to_hv_device(dev);
 280
 281         if (!hv_dev->channel)
 282                 return -ENODEV;
 283         return sprintf(buf, "%d\n",
 284                        channel_latency(hv_dev->channel,
 285                                        vmbus_connection.monitor_pages[0]));
 286 }
 287 static DEVICE_ATTR_RO(server_monitor_latency);
 288
 289 static ssize_t client_monitor_latency_show(struct device *dev,
 290                                            struct device_attribute *dev_attr,
 291                                            char *buf)
 292 {
 293         struct hv_device *hv_dev = device_to_hv_device(dev);
 294
 295         if (!hv_dev->channel)
 296                 return -ENODEV;
 297         return sprintf(buf, "%d\n",
 298                        channel_latency(hv_dev->channel,
 299                                        vmbus_connection.monitor_pages[1]));
 300 }
 301 static DEVICE_ATTR_RO(client_monitor_latency);
 302
 303 static ssize_t server_monitor_conn_id_show(struct device *dev,
 304                                            struct device_attribute *dev_attr,
 305                                            char *buf)
 306 {
 307         struct hv_device *hv_dev = device_to_hv_device(dev);
 308
 309         if (!hv_dev->channel)
 310                 return -ENODEV;
 311         return sprintf(buf, "%d\n",
 312                        channel_conn_id(hv_dev->channel,
 313                                        vmbus_connection.monitor_pages[0]));
 314 }
 315 static DEVICE_ATTR_RO(server_monitor_conn_id);
 316
 317 static ssize_t client_monitor_conn_id_show(struct device *dev,
 318                                            struct device_attribute *dev_attr,
 319                                            char *buf)
 320 {
 321         struct hv_device *hv_dev = device_to_hv_device(dev);
 322
 323         if (!hv_dev->channel)
 324                 return -ENODEV;
 325         return sprintf(buf, "%d\n",
 326                        channel_conn_id(hv_dev->channel,
 327                                        vmbus_connection.monitor_pages[1]));
 328 }
 329 static DEVICE_ATTR_RO(client_monitor_conn_id);
 330
 331 static ssize_t out_intr_mask_show(struct device *dev,
 332                                   struct device_attribute *dev_attr, char *buf)
 333 {
 334         struct hv_device *hv_dev = device_to_hv_device(dev);
 335         struct hv_ring_buffer_debug_info outbound;
 336         int ret;
 337
 338         if (!hv_dev->channel)
 339                 return -ENODEV;
 340
 341         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
 342                                           &outbound);
 343         if (ret < 0)
 344                 return ret;
 345
 346         return sprintf(buf, "%d\n", outbound.current_interrupt_mask);
 347 }
 348 static DEVICE_ATTR_RO(out_intr_mask);
 349
 350 static ssize_t out_read_index_show(struct device *dev,
 351                                    struct device_attribute *dev_attr, char *buf)
 352 {
 353         struct hv_device *hv_dev = device_to_hv_device(dev);
 354         struct hv_ring_buffer_debug_info outbound;
 355         int ret;
 356
 357         if (!hv_dev->channel)
 358                 return -ENODEV;
 359
 360         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
 361                                           &outbound);
 362         if (ret < 0)
 363                 return ret;
 364         return sprintf(buf, "%d\n", outbound.current_read_index);
 365 }
 366 static DEVICE_ATTR_RO(out_read_index);
 367
 368 static ssize_t out_write_index_show(struct device *dev,
 369                                     struct device_attribute *dev_attr,
 370                                     char *buf)
 371 {
 372         struct hv_device *hv_dev = device_to_hv_device(dev);
 373         struct hv_ring_buffer_debug_info outbound;
 374         int ret;
 375
 376         if (!hv_dev->channel)
 377                 return -ENODEV;
 378
 379         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
 380                                           &outbound);
 381         if (ret < 0)
 382                 return ret;
 383         return sprintf(buf, "%d\n", outbound.current_write_index);
 384 }
 385 static DEVICE_ATTR_RO(out_write_index);
 386
 387 static ssize_t out_read_bytes_avail_show(struct device *dev,
 388                                          struct device_attribute *dev_attr,
 389                                          char *buf)
 390 {
 391         struct hv_device *hv_dev = device_to_hv_device(dev);
 392         struct hv_ring_buffer_debug_info outbound;
 393         int ret;
 394
 395         if (!hv_dev->channel)
 396                 return -ENODEV;
 397
 398         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
 399                                           &outbound);
 400         if (ret < 0)
 401                 return ret;
 402         return sprintf(buf, "%d\n", outbound.bytes_avail_toread);
 403 }
 404 static DEVICE_ATTR_RO(out_read_bytes_avail);
 405
 406 static ssize_t out_write_bytes_avail_show(struct device *dev,
 407                                           struct device_attribute *dev_attr,
 408                                           char *buf)
 409 {
 410         struct hv_device *hv_dev = device_to_hv_device(dev);
 411         struct hv_ring_buffer_debug_info outbound;
 412         int ret;
 413
 414         if (!hv_dev->channel)
 415                 return -ENODEV;
 416
 417         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
 418                                           &outbound);
 419         if (ret < 0)
 420                 return ret;
 421         return sprintf(buf, "%d\n", outbound.bytes_avail_towrite);
 422 }
 423 static DEVICE_ATTR_RO(out_write_bytes_avail);
 424
 425 static ssize_t in_intr_mask_show(struct device *dev,
 426                                  struct device_attribute *dev_attr, char *buf)
 427 {
 428         struct hv_device *hv_dev = device_to_hv_device(dev);
 429         struct hv_ring_buffer_debug_info inbound;
 430         int ret;
 431
 432         if (!hv_dev->channel)
 433                 return -ENODEV;
 434
 435         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 436         if (ret < 0)
 437                 return ret;
 438
 439         return sprintf(buf, "%d\n", inbound.current_interrupt_mask);
 440 }
 441 static DEVICE_ATTR_RO(in_intr_mask);
 442
 443 static ssize_t in_read_index_show(struct device *dev,
 444                                   struct device_attribute *dev_attr, char *buf)
 445 {
 446         struct hv_device *hv_dev = device_to_hv_device(dev);
 447         struct hv_ring_buffer_debug_info inbound;
 448         int ret;
 449
 450         if (!hv_dev->channel)
 451                 return -ENODEV;
 452
 453         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 454         if (ret < 0)
 455                 return ret;
 456
 457         return sprintf(buf, "%d\n", inbound.current_read_index);
 458 }
 459 static DEVICE_ATTR_RO(in_read_index);
 460
 461 static ssize_t in_write_index_show(struct device *dev,
 462                                    struct device_attribute *dev_attr, char *buf)
 463 {
 464         struct hv_device *hv_dev = device_to_hv_device(dev);
 465         struct hv_ring_buffer_debug_info inbound;
 466         int ret;
 467
 468         if (!hv_dev->channel)
 469                 return -ENODEV;
 470
 471         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 472         if (ret < 0)
 473                 return ret;
 474
 475         return sprintf(buf, "%d\n", inbound.current_write_index);
 476 }
 477 static DEVICE_ATTR_RO(in_write_index);
 478
 479 static ssize_t in_read_bytes_avail_show(struct device *dev,
 480                                         struct device_attribute *dev_attr,
 481                                         char *buf)
 482 {
 483         struct hv_device *hv_dev = device_to_hv_device(dev);
 484         struct hv_ring_buffer_debug_info inbound;
 485         int ret;
 486
 487         if (!hv_dev->channel)
 488                 return -ENODEV;
 489
 490         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 491         if (ret < 0)
 492                 return ret;
 493
 494         return sprintf(buf, "%d\n", inbound.bytes_avail_toread);
 495 }
 496 static DEVICE_ATTR_RO(in_read_bytes_avail);
 497
 498 static ssize_t in_write_bytes_avail_show(struct device *dev,
 499                                          struct device_attribute *dev_attr,
 500                                          char *buf)
 501 {
 502         struct hv_device *hv_dev = device_to_hv_device(dev);
 503         struct hv_ring_buffer_debug_info inbound;
 504         int ret;
 505
 506         if (!hv_dev->channel)
 507                 return -ENODEV;
 508
 509         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 510         if (ret < 0)
 511                 return ret;
 512
 513         return sprintf(buf, "%d\n", inbound.bytes_avail_towrite);
 514 }
 515 static DEVICE_ATTR_RO(in_write_bytes_avail);
 516
 517 static ssize_t channel_vp_mapping_show(struct device *dev,
 518                                        struct device_attribute *dev_attr,
 519                                        char *buf)
 520 {
 521         struct hv_device *hv_dev = device_to_hv_device(dev);
 522         struct vmbus_channel *channel = hv_dev->channel, *cur_sc;
 523         int buf_size = PAGE_SIZE, n_written, tot_written;
 524         struct list_head *cur;
 525
 526         if (!channel)
 527                 return -ENODEV;
 528
 529         mutex_lock(&vmbus_connection.channel_mutex);
 530
 531         tot_written = snprintf(buf, buf_size, "%u:%u\n",
 532                 channel->offermsg.child_relid, channel->target_cpu);
 533
 534         list_for_each(cur, &channel->sc_list) {
 535                 if (tot_written >= buf_size - 1)
 536                         break;
 537
 538                 cur_sc = list_entry(cur, struct vmbus_channel, sc_list);
 539                 n_written = scnprintf(buf + tot_written,
 540                                      buf_size - tot_written,
 541                                      "%u:%u\n",
 542                                      cur_sc->offermsg.child_relid,
 543                                      cur_sc->target_cpu);
 544                 tot_written += n_written;
 545         }
 546
 547         mutex_unlock(&vmbus_connection.channel_mutex);
 548
 549         return tot_written;
 550 }
 551 static DEVICE_ATTR_RO(channel_vp_mapping);
 552
 553 static ssize_t vendor_show(struct device *dev,
 554                            struct device_attribute *dev_attr,
 555                            char *buf)
 556 {
 557         struct hv_device *hv_dev = device_to_hv_device(dev);
 558
 559         return sprintf(buf, "0x%x\n", hv_dev->vendor_id);
 560 }
 561 static DEVICE_ATTR_RO(vendor);
 562
 563 static ssize_t device_show(struct device *dev,
 564                            struct device_attribute *dev_attr,
 565                            char *buf)
 566 {
 567         struct hv_device *hv_dev = device_to_hv_device(dev);
 568
 569         return sprintf(buf, "0x%x\n", hv_dev->device_id);
 570 }
 571 static DEVICE_ATTR_RO(device);
 572
 573 static ssize_t driver_override_store(struct device *dev,
 574                                      struct device_attribute *attr,
 575                                      const char *buf, size_t count)
 576 {
 577         struct hv_device *hv_dev = device_to_hv_device(dev);
 578         char *driver_override, *old, *cp;
 579
 580         /* We need to keep extra room for a newline */
 581         if (count >= (PAGE_SIZE - 1))
 582                 return -EINVAL;
 583
 584         driver_override = kstrndup(buf, count, GFP_KERNEL);
 585         if (!driver_override)
 586                 return -ENOMEM;
 587
 588         cp = strchr(driver_override, '\n');
 589         if (cp)
 590                 *cp = '\0';
 591
 592         device_lock(dev);
 593         old = hv_dev->driver_override;
 594         if (strlen(driver_override)) {
 595                 hv_dev->driver_override = driver_override;
 596         } else {
 597                 kfree(driver_override);
 598                 hv_dev->driver_override = NULL;
 599         }
 600         device_unlock(dev);
 601
 602         kfree(old);
 603
 604         return count;
 605 }
 606
 607 static ssize_t driver_override_show(struct device *dev,
 608                                     struct device_attribute *attr, char *buf)
 609 {
 610         struct hv_device *hv_dev = device_to_hv_device(dev);
 611         ssize_t len;
 612
 613         device_lock(dev);
 614         len = snprintf(buf, PAGE_SIZE, "%s\n", hv_dev->driver_override);
 615         device_unlock(dev);
 616
 617         return len;
 618 }
 619 static DEVICE_ATTR_RW(driver_override);
 620
 621 /* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
 622 static struct attribute *vmbus_dev_attrs[] = {
 623         &dev_attr_id.attr,
 624         &dev_attr_state.attr,
 625         &dev_attr_monitor_id.attr,
 626         &dev_attr_class_id.attr,
 627         &dev_attr_device_id.attr,
 628         &dev_attr_modalias.attr,
 629 #ifdef CONFIG_NUMA
 630         &dev_attr_numa_node.attr,
 631 #endif
 632         &dev_attr_server_monitor_pending.attr,
 633         &dev_attr_client_monitor_pending.attr,
 634         &dev_attr_server_monitor_latency.attr,
 635         &dev_attr_client_monitor_latency.attr,
 636         &dev_attr_server_monitor_conn_id.attr,
 637         &dev_attr_client_monitor_conn_id.attr,
 638         &dev_attr_out_intr_mask.attr,
 639         &dev_attr_out_read_index.attr,
 640         &dev_attr_out_write_index.attr,
 641         &dev_attr_out_read_bytes_avail.attr,
 642         &dev_attr_out_write_bytes_avail.attr,
 643         &dev_attr_in_intr_mask.attr,
 644         &dev_attr_in_read_index.attr,
 645         &dev_attr_in_write_index.attr,
 646         &dev_attr_in_read_bytes_avail.attr,
 647         &dev_attr_in_write_bytes_avail.attr,
 648         &dev_attr_channel_vp_mapping.attr,
 649         &dev_attr_vendor.attr,
 650         &dev_attr_device.attr,
 651         &dev_attr_driver_override.attr,
 652         NULL,
 653 };
 654
 655 /*
 656  * Device-level attribute_group callback function. Returns the permission for
 657  * each attribute, and returns 0 if an attribute is not visible.
 658  */
 659 static umode_t vmbus_dev_attr_is_visible(struct kobject *kobj,
 660                                          struct attribute *attr, int idx)
 661 {
 662         struct device *dev = kobj_to_dev(kobj);
 663         const struct hv_device *hv_dev = device_to_hv_device(dev);
 664
 665         /* Hide the monitor attributes if the monitor mechanism is not used. */
 666         if (!hv_dev->channel->offermsg.monitor_allocated &&
 667             (attr == &dev_attr_monitor_id.attr ||
 668              attr == &dev_attr_server_monitor_pending.attr ||
 669              attr == &dev_attr_client_monitor_pending.attr ||
 670              attr == &dev_attr_server_monitor_latency.attr ||
 671              attr == &dev_attr_client_monitor_latency.attr ||
 672              attr == &dev_attr_server_monitor_conn_id.attr ||
 673              attr == &dev_attr_client_monitor_conn_id.attr))
 674                 return 0;
 675
 676         return attr->mode;
 677 }
 678
 679 static const struct attribute_group vmbus_dev_group = {
 680         .attrs = vmbus_dev_attrs,
 681         .is_visible = vmbus_dev_attr_is_visible
 682 };
 683 __ATTRIBUTE_GROUPS(vmbus_dev);
 684
 685 /* Set up the attribute for /sys/bus/vmbus/hibernation */
 686 static ssize_t hibernation_show(struct bus_type *bus, char *buf)
 687 {
 688         return sprintf(buf, "%d\n", !!hv_is_hibernation_supported());
 689 }
 690
 691 static BUS_ATTR_RO(hibernation);
 692
 693 static struct attribute *vmbus_bus_attrs[] = {
 694         &bus_attr_hibernation.attr,
 695         NULL,
 696 };
 697 static const struct attribute_group vmbus_bus_group = {
 698         .attrs = vmbus_bus_attrs,
 699 };
 700 __ATTRIBUTE_GROUPS(vmbus_bus);
 701
 702 /*
 703  * vmbus_uevent - add uevent for our device
 704  *
 705  * This routine is invoked when a device is added or removed on the vmbus to
 706  * generate a uevent to udev in the userspace. The udev will then look at its
 707  * rule and the uevent generated here to load the appropriate driver
 708  *
 709  * The alias string will be of the form vmbus:guid where guid is the string
 710  * representation of the device guid (each byte of the guid will be
 711  * represented with two hex characters.
 712  */
 713 static int vmbus_uevent(struct device *device, struct kobj_uevent_env *env)
 714 {
 715         struct hv_device *dev = device_to_hv_device(device);
 716         const char *format = "MODALIAS=vmbus:%*phN";
 717
 718         return add_uevent_var(env, format, UUID_SIZE, &dev->dev_type);
 719 }
 720
 721 static const struct hv_vmbus_device_id *
 722 hv_vmbus_dev_match(const struct hv_vmbus_device_id *id, const guid_t *guid)
 723 {
 724         if (id == NULL)
 725                 return NULL; /* empty device table */
 726
 727         for (; !guid_is_null(&id->guid); id++)
 728                 if (guid_equal(&id->guid, guid))
 729                         return id;
 730
 731         return NULL;
 732 }
 733
 734 static const struct hv_vmbus_device_id *
 735 hv_vmbus_dynid_match(struct hv_driver *drv, const guid_t *guid)
 736 {
 737         const struct hv_vmbus_device_id *id = NULL;
 738         struct vmbus_dynid *dynid;
 739
 740         spin_lock(&drv->dynids.lock);
 741         list_for_each_entry(dynid, &drv->dynids.list, node) {
 742                 if (guid_equal(&dynid->id.guid, guid)) {
 743                         id = &dynid->id;
 744                         break;
 745                 }
 746         }
 747         spin_unlock(&drv->dynids.lock);
 748
 749         return id;
 750 }
 751
 752 static const struct hv_vmbus_device_id vmbus_device_null;
 753
 754 /*
 755  * Return a matching hv_vmbus_device_id pointer.
 756  * If there is no match, return NULL.
 757  */
 758 static const struct hv_vmbus_device_id *hv_vmbus_get_id(struct hv_driver *drv,
 759                                                         struct hv_device *dev)
 760 {
 761         const guid_t *guid = &dev->dev_type;
 762         const struct hv_vmbus_device_id *id;
 763
 764         /* When driver_override is set, only bind to the matching driver */
 765         if (dev->driver_override && strcmp(dev->driver_override, drv->name))
 766                 return NULL;
 767
 768         /* Look at the dynamic ids first, before the static ones */
 769         id = hv_vmbus_dynid_match(drv, guid);
 770         if (!id)
 771                 id = hv_vmbus_dev_match(drv->id_table, guid);
 772
 773         /* driver_override will always match, send a dummy id */
 774         if (!id && dev->driver_override)
 775                 id = &vmbus_device_null;
 776
 777         return id;
 778 }
 779
 780 /* vmbus_add_dynid - add a new device ID to this driver and re-probe devices */
 781 static int vmbus_add_dynid(struct hv_driver *drv, guid_t *guid)
 782 {
 783         struct vmbus_dynid *dynid;
 784
 785         dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
 786         if (!dynid)
 787                 return -ENOMEM;
 788
 789         dynid->id.guid = *guid;
 790
 791         spin_lock(&drv->dynids.lock);
 792         list_add_tail(&dynid->node, &drv->dynids.list);
 793         spin_unlock(&drv->dynids.lock);
 794
 795         return driver_attach(&drv->driver);
 796 }
 797
 798 static void vmbus_free_dynids(struct hv_driver *drv)
 799 {
 800         struct vmbus_dynid *dynid, *n;
 801
 802         spin_lock(&drv->dynids.lock);
 803         list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
 804                 list_del(&dynid->node);
 805                 kfree(dynid);
 806         }
 807         spin_unlock(&drv->dynids.lock);
 808 }
 809
 810 /*
 811  * store_new_id - sysfs frontend to vmbus_add_dynid()
 812  *
 813  * Allow GUIDs to be added to an existing driver via sysfs.
 814  */
 815 static ssize_t new_id_store(struct device_driver *driver, const char *buf,
 816                             size_t count)
 817 {
 818         struct hv_driver *drv = drv_to_hv_drv(driver);
 819         guid_t guid;
 820         ssize_t retval;
 821
 822         retval = guid_parse(buf, &guid);
 823         if (retval)
 824                 return retval;
 825
 826         if (hv_vmbus_dynid_match(drv, &guid))
 827                 return -EEXIST;
 828
 829         retval = vmbus_add_dynid(drv, &guid);
 830         if (retval)
 831                 return retval;
 832         return count;
 833 }
 834 static DRIVER_ATTR_WO(new_id);
 835
 836 /*
 837  * store_remove_id - remove a PCI device ID from this driver
 838  *
 839  * Removes a dynamic pci device ID to this driver.
 840  */
 841 static ssize_t remove_id_store(struct device_driver *driver, const char *buf,
 842                                size_t count)
 843 {
 844         struct hv_driver *drv = drv_to_hv_drv(driver);
 845         struct vmbus_dynid *dynid, *n;
 846         guid_t guid;
 847         ssize_t retval;
 848
 849         retval = guid_parse(buf, &guid);
 850         if (retval)
 851                 return retval;
 852
 853         retval = -ENODEV;
 854         spin_lock(&drv->dynids.lock);
 855         list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
 856                 struct hv_vmbus_device_id *id = &dynid->id;
 857
 858                 if (guid_equal(&id->guid, &guid)) {
 859                         list_del(&dynid->node);
 860                         kfree(dynid);
 861                         retval = count;
 862                         break;
 863                 }
 864         }
 865         spin_unlock(&drv->dynids.lock);
 866
 867         return retval;
 868 }
 869 static DRIVER_ATTR_WO(remove_id);
 870
 871 static struct attribute *vmbus_drv_attrs[] = {
 872         &driver_attr_new_id.attr,
 873         &driver_attr_remove_id.attr,
 874         NULL,
 875 };
 876 ATTRIBUTE_GROUPS(vmbus_drv);
 877
 878
 879 /*
 880  * vmbus_match - Attempt to match the specified device to the specified driver
 881  */
 882 static int vmbus_match(struct device *device, struct device_driver *driver)
 883 {
 884         struct hv_driver *drv = drv_to_hv_drv(driver);
 885         struct hv_device *hv_dev = device_to_hv_device(device);
 886
 887         /* The hv_sock driver handles all hv_sock offers. */
 888         if (is_hvsock_channel(hv_dev->channel))
 889                 return drv->hvsock;
 890
 891         if (hv_vmbus_get_id(drv, hv_dev))
 892                 return 1;
 893
 894         return 0;
 895 }
 896
 897 /*
 898  * vmbus_probe - Add the new vmbus's child device
 899  */
 900 static int vmbus_probe(struct device *child_device)
 901 {
 902         int ret = 0;
 903         struct hv_driver *drv =
 904                         drv_to_hv_drv(child_device->driver);
 905         struct hv_device *dev = device_to_hv_device(child_device);
 906         const struct hv_vmbus_device_id *dev_id;
 907
 908         dev_id = hv_vmbus_get_id(drv, dev);
 909         if (drv->probe) {
 910                 ret = drv->probe(dev, dev_id);
 911                 if (ret != 0)
 912                         pr_err("probe failed for device %s (%d)\n",
 913                                dev_name(child_device), ret);
 914
 915         } else {
 916                 pr_err("probe not set for driver %s\n",
 917                        dev_name(child_device));
 918                 ret = -ENODEV;
 919         }
 920         return ret;
 921 }
 922
 923 /*
 924  * vmbus_dma_configure -- Configure DMA coherence for VMbus device
 925  */
 926 static int vmbus_dma_configure(struct device *child_device)
 927 {
 928         /*
 929          * On ARM64, propagate the DMA coherence setting from the top level
 930          * VMbus ACPI device to the child VMbus device being added here.
 931          * On x86/x64 coherence is assumed and these calls have no effect.
 932          */
 933         hv_setup_dma_ops(child_device,
 934                 device_get_dma_attr(&hv_acpi_dev->dev) == DEV_DMA_COHERENT);
 935         return 0;
 936 }
 937
 938 /*
 939  * vmbus_remove - Remove a vmbus device
 940  */
 941 static void vmbus_remove(struct device *child_device)
 942 {
 943         struct hv_driver *drv;
 944         struct hv_device *dev = device_to_hv_device(child_device);
 945
 946         if (child_device->driver) {
 947                 drv = drv_to_hv_drv(child_device->driver);
 948                 if (drv->remove)
 949                         drv->remove(dev);
 950         }
 951 }
 952
 953 /*
 954  * vmbus_shutdown - Shutdown a vmbus device
 955  */
 956 static void vmbus_shutdown(struct device *child_device)
 957 {
 958         struct hv_driver *drv;
 959         struct hv_device *dev = device_to_hv_device(child_device);
 960
 961
 962         /* The device may not be attached yet */
 963         if (!child_device->driver)
 964                 return;
 965
 966         drv = drv_to_hv_drv(child_device->driver);
 967
 968         if (drv->shutdown)
 969                 drv->shutdown(dev);
 970 }
 971
 972 #ifdef CONFIG_PM_SLEEP
 973 /*
 974  * vmbus_suspend - Suspend a vmbus device
 975  */
 976 static int vmbus_suspend(struct device *child_device)
 977 {
 978         struct hv_driver *drv;
 979         struct hv_device *dev = device_to_hv_device(child_device);
 980
 981         /* The device may not be attached yet */
 982         if (!child_device->driver)
 983                 return 0;
 984
 985         drv = drv_to_hv_drv(child_device->driver);
 986         if (!drv->suspend)
 987                 return -EOPNOTSUPP;
 988
 989         return drv->suspend(dev);
 990 }
 991
 992 /*
 993  * vmbus_resume - Resume a vmbus device
 994  */
 995 static int vmbus_resume(struct device *child_device)
 996 {
 997         struct hv_driver *drv;
 998         struct hv_device *dev = device_to_hv_device(child_device);
 999
1000         /* The device may not be attached yet */
1001         if (!child_device->driver)
1002                 return 0;
1003
1004         drv = drv_to_hv_drv(child_device->driver);
1005         if (!drv->resume)
1006                 return -EOPNOTSUPP;
1007
1008         return drv->resume(dev);
1009 }
1010 #else
1011 #define vmbus_suspend NULL
1012 #define vmbus_resume NULL
1013 #endif /* CONFIG_PM_SLEEP */
1014
1015 /*
1016  * vmbus_device_release - Final callback release of the vmbus child device
1017  */
1018 static void vmbus_device_release(struct device *device)
1019 {
1020         struct hv_device *hv_dev = device_to_hv_device(device);
1021         struct vmbus_channel *channel = hv_dev->channel;
1022
1023         hv_debug_rm_dev_dir(hv_dev);
1024
1025         mutex_lock(&vmbus_connection.channel_mutex);
1026         hv_process_channel_removal(channel);
1027         mutex_unlock(&vmbus_connection.channel_mutex);
1028         kfree(hv_dev);
1029 }
1030
1031 /*
1032  * Note: we must use the "noirq" ops: see the comment before vmbus_bus_pm.
1033  *
1034  * suspend_noirq/resume_noirq are set to NULL to support Suspend-to-Idle: we
1035  * shouldn't suspend the vmbus devices upon Suspend-to-Idle, otherwise there
1036  * is no way to wake up a Generation-2 VM.
1037  *
1038  * The other 4 ops are for hibernation.
1039  */
1040
1041 static const struct dev_pm_ops vmbus_pm = {
1042         .suspend_noirq  = NULL,
1043         .resume_noirq   = NULL,
1044         .freeze_noirq   = vmbus_suspend,
1045         .thaw_noirq     = vmbus_resume,
1046         .poweroff_noirq = vmbus_suspend,
1047         .restore_noirq  = vmbus_resume,
1048 };
1049
1050 /* The one and only one */
1051 static struct bus_type  hv_bus = {
1052         .name =         "vmbus",
1053         .match =                vmbus_match,
1054         .shutdown =             vmbus_shutdown,
1055         .remove =               vmbus_remove,
1056         .probe =                vmbus_probe,
1057         .uevent =               vmbus_uevent,
1058         .dma_configure =        vmbus_dma_configure,
1059         .dev_groups =           vmbus_dev_groups,
1060         .drv_groups =           vmbus_drv_groups,
1061         .bus_groups =           vmbus_bus_groups,
1062         .pm =                   &vmbus_pm,
1063 };
1064
1065 struct onmessage_work_context {
1066         struct work_struct work;
1067         struct {
1068                 struct hv_message_header header;
1069                 u8 payload[];
1070         } msg;
1071 };
1072
1073 static void vmbus_onmessage_work(struct work_struct *work)
1074 {
1075         struct onmessage_work_context *ctx;
1076
1077         /* Do not process messages if we're in DISCONNECTED state */
1078         if (vmbus_connection.conn_state == DISCONNECTED)
1079                 return;
1080
1081         ctx = container_of(work, struct onmessage_work_context,
1082                            work);
1083         vmbus_onmessage((struct vmbus_channel_message_header *)
1084                         &ctx->msg.payload);
1085         kfree(ctx);
1086 }
1087
1088 void vmbus_on_msg_dpc(unsigned long data)
1089 {
1090         struct hv_per_cpu_context *hv_cpu = (void *)data;
1091         void *page_addr = hv_cpu->synic_message_page;
1092         struct hv_message msg_copy, *msg = (struct hv_message *)page_addr +
1093                                   VMBUS_MESSAGE_SINT;
1094         struct vmbus_channel_message_header *hdr;
1095         enum vmbus_channel_message_type msgtype;
1096         const struct vmbus_channel_message_table_entry *entry;
1097         struct onmessage_work_context *ctx;
1098         __u8 payload_size;
1099         u32 message_type;
1100
1101         /*
1102          * 'enum vmbus_channel_message_type' is supposed to always be 'u32' as
1103          * it is being used in 'struct vmbus_channel_message_header' definition
1104          * which is supposed to match hypervisor ABI.
1105          */
1106         BUILD_BUG_ON(sizeof(enum vmbus_channel_message_type) != sizeof(u32));
1107
1108         /*
1109          * Since the message is in memory shared with the host, an erroneous or
1110          * malicious Hyper-V could modify the message while vmbus_on_msg_dpc()
1111          * or individual message handlers are executing; to prevent this, copy
1112          * the message into private memory.
1113          */
1114         memcpy(&msg_copy, msg, sizeof(struct hv_message));
1115
1116         message_type = msg_copy.header.message_type;
1117         if (message_type == HVMSG_NONE)
1118                 /* no msg */
1119                 return;
1120
1121         hdr = (struct vmbus_channel_message_header *)msg_copy.u.payload;
1122         msgtype = hdr->msgtype;
1123
1124         trace_vmbus_on_msg_dpc(hdr);
1125
1126         if (msgtype >= CHANNELMSG_COUNT) {
1127                 WARN_ONCE(1, "unknown msgtype=%d\n", msgtype);
1128                 goto msg_handled;
1129         }
1130
1131         payload_size = msg_copy.header.payload_size;
1132         if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT) {
1133                 WARN_ONCE(1, "payload size is too large (%d)\n", payload_size);
1134                 goto msg_handled;
1135         }
1136
1137         entry = &channel_message_table[msgtype];
1138
1139         if (!entry->message_handler)
1140                 goto msg_handled;
1141
1142         if (payload_size < entry->min_payload_len) {
1143                 WARN_ONCE(1, "message too short: msgtype=%d len=%d\n", msgtype, payload_size);
1144                 goto msg_handled;
1145         }
1146
1147         if (entry->handler_type == VMHT_BLOCKING) {
1148                 ctx = kmalloc(struct_size(ctx, msg.payload, payload_size), GFP_ATOMIC);
1149                 if (ctx == NULL)
1150                         return;
1151
1152                 INIT_WORK(&ctx->work, vmbus_onmessage_work);
1153                 memcpy(&ctx->msg, &msg_copy, sizeof(msg->header) + payload_size);
1154
1155                 /*
1156                  * The host can generate a rescind message while we
1157                  * may still be handling the original offer. We deal with
1158                  * this condition by relying on the synchronization provided
1159                  * by offer_in_progress and by channel_mutex.  See also the
1160                  * inline comments in vmbus_onoffer_rescind().
1161                  */
1162                 switch (msgtype) {
1163                 case CHANNELMSG_RESCIND_CHANNELOFFER:
1164                         /*
1165                          * If we are handling the rescind message;
1166                          * schedule the work on the global work queue.
1167                          *
1168                          * The OFFER message and the RESCIND message should
1169                          * not be handled by the same serialized work queue,
1170                          * because the OFFER handler may call vmbus_open(),
1171                          * which tries to open the channel by sending an
1172                          * OPEN_CHANNEL message to the host and waits for
1173                          * the host's response; however, if the host has
1174                          * rescinded the channel before it receives the
1175                          * OPEN_CHANNEL message, the host just silently
1176                          * ignores the OPEN_CHANNEL message; as a result,
1177                          * the guest's OFFER handler hangs for ever, if we
1178                          * handle the RESCIND message in the same serialized
1179                          * work queue: the RESCIND handler can not start to
1180                          * run before the OFFER handler finishes.
1181                          */
1182                         schedule_work(&ctx->work);
1183                         break;
1184
1185                 case CHANNELMSG_OFFERCHANNEL:
1186                         /*
1187                          * The host sends the offer message of a given channel
1188                          * before sending the rescind message of the same
1189                          * channel.  These messages are sent to the guest's
1190                          * connect CPU; the guest then starts processing them
1191                          * in the tasklet handler on this CPU:
1192                          *
1193                          * VMBUS_CONNECT_CPU
1194                          *
1195                          * [vmbus_on_msg_dpc()]
1196                          * atomic_inc()  // CHANNELMSG_OFFERCHANNEL
1197                          * queue_work()
1198                          * ...
1199                          * [vmbus_on_msg_dpc()]
1200                          * schedule_work()  // CHANNELMSG_RESCIND_CHANNELOFFER
1201                          *
1202                          * We rely on the memory-ordering properties of the
1203                          * queue_work() and schedule_work() primitives, which
1204                          * guarantee that the atomic increment will be visible
1205                          * to the CPUs which will execute the offer & rescind
1206                          * works by the time these works will start execution.
1207                          */
1208                         atomic_inc(&vmbus_connection.offer_in_progress);
1209                         fallthrough;
1210
1211                 default:
1212                         queue_work(vmbus_connection.work_queue, &ctx->work);
1213                 }
1214         } else
1215                 entry->message_handler(hdr);
1216
1217 msg_handled:
1218         vmbus_signal_eom(msg, message_type);
1219 }
1220
1221 #ifdef CONFIG_PM_SLEEP
1222 /*
1223  * Fake RESCIND_CHANNEL messages to clean up hv_sock channels by force for
1224  * hibernation, because hv_sock connections can not persist across hibernation.
1225  */
1226 static void vmbus_force_channel_rescinded(struct vmbus_channel *channel)
1227 {
1228         struct onmessage_work_context *ctx;
1229         struct vmbus_channel_rescind_offer *rescind;
1230
1231         WARN_ON(!is_hvsock_channel(channel));
1232
1233         /*
1234          * Allocation size is small and the allocation should really not fail,
1235          * otherwise the state of the hv_sock connections ends up in limbo.
1236          */
1237         ctx = kzalloc(sizeof(*ctx) + sizeof(*rescind),
1238                       GFP_KERNEL | __GFP_NOFAIL);
1239
1240         /*
1241          * So far, these are not really used by Linux. Just set them to the
1242          * reasonable values conforming to the definitions of the fields.
1243          */
1244         ctx->msg.header.message_type = 1;
1245         ctx->msg.header.payload_size = sizeof(*rescind);
1246
1247         /* These values are actually used by Linux. */
1248         rescind = (struct vmbus_channel_rescind_offer *)ctx->msg.payload;
1249         rescind->header.msgtype = CHANNELMSG_RESCIND_CHANNELOFFER;
1250         rescind->child_relid = channel->offermsg.child_relid;
1251
1252         INIT_WORK(&ctx->work, vmbus_onmessage_work);
1253
1254         queue_work(vmbus_connection.work_queue, &ctx->work);
1255 }
1256 #endif /* CONFIG_PM_SLEEP */
1257
1258 /*
1259  * Schedule all channels with events pending
1260  */
1261 static void vmbus_chan_sched(struct hv_per_cpu_context *hv_cpu)
1262 {
1263         unsigned long *recv_int_page;
1264         u32 maxbits, relid;
1265
1266         if (vmbus_proto_version < VERSION_WIN8) {
1267                 maxbits = MAX_NUM_CHANNELS_SUPPORTED;
1268                 recv_int_page = vmbus_connection.recv_int_page;
1269         } else {
1270                 /*
1271                  * When the host is win8 and beyond, the event page
1272                  * can be directly checked to get the id of the channel
1273                  * that has the interrupt pending.
1274                  */
1275                 void *page_addr = hv_cpu->synic_event_page;
1276                 union hv_synic_event_flags *event
1277                         = (union hv_synic_event_flags *)page_addr +
1278                                                  VMBUS_MESSAGE_SINT;
1279
1280                 maxbits = HV_EVENT_FLAGS_COUNT;
1281                 recv_int_page = event->flags;
1282         }
1283
1284         if (unlikely(!recv_int_page))
1285                 return;
1286
1287         for_each_set_bit(relid, recv_int_page, maxbits) {
1288                 void (*callback_fn)(void *context);
1289                 struct vmbus_channel *channel;
1290
1291                 if (!sync_test_and_clear_bit(relid, recv_int_page))
1292                         continue;
1293
1294                 /* Special case - vmbus channel protocol msg */
1295                 if (relid == 0)
1296                         continue;
1297
1298                 /*
1299                  * Pairs with the kfree_rcu() in vmbus_chan_release().
1300                  * Guarantees that the channel data structure doesn't
1301                  * get freed while the channel pointer below is being
1302                  * dereferenced.
1303                  */
1304                 rcu_read_lock();
1305
1306                 /* Find channel based on relid */
1307                 channel = relid2channel(relid);
1308                 if (channel == NULL)
1309                         goto sched_unlock_rcu;
1310
1311                 if (channel->rescind)
1312                         goto sched_unlock_rcu;
1313
1314                 /*
1315                  * Make sure that the ring buffer data structure doesn't get
1316                  * freed while we dereference the ring buffer pointer.  Test
1317                  * for the channel's onchannel_callback being NULL within a
1318                  * sched_lock critical section.  See also the inline comments
1319                  * in vmbus_reset_channel_cb().
1320                  */
1321                 spin_lock(&channel->sched_lock);
1322
1323                 callback_fn = channel->onchannel_callback;
1324                 if (unlikely(callback_fn == NULL))
1325                         goto sched_unlock;
1326
1327                 trace_vmbus_chan_sched(channel);
1328
1329                 ++channel->interrupts;
1330
1331                 switch (channel->callback_mode) {
1332                 case HV_CALL_ISR:
1333                         (*callback_fn)(channel->channel_callback_context);
1334                         break;
1335
1336                 case HV_CALL_BATCHED:
1337                         hv_begin_read(&channel->inbound);
1338                         fallthrough;
1339                 case HV_CALL_DIRECT:
1340                         tasklet_schedule(&channel->callback_event);
1341                 }
1342
1343 sched_unlock:
1344                 spin_unlock(&channel->sched_lock);
1345 sched_unlock_rcu:
1346                 rcu_read_unlock();
1347         }
1348 }
1349
1350 static void vmbus_isr(void)
1351 {
1352         struct hv_per_cpu_context *hv_cpu
1353                 = this_cpu_ptr(hv_context.cpu_context);
1354         void *page_addr = hv_cpu->synic_event_page;
1355         struct hv_message *msg;
1356         union hv_synic_event_flags *event;
1357         bool handled = false;
1358
1359         if (unlikely(page_addr == NULL))
1360                 return;
1361
1362         event = (union hv_synic_event_flags *)page_addr +
1363                                          VMBUS_MESSAGE_SINT;
1364         /*
1365          * Check for events before checking for messages. This is the order
1366          * in which events and messages are checked in Windows guests on
1367          * Hyper-V, and the Windows team suggested we do the same.
1368          */
1369
1370         if ((vmbus_proto_version == VERSION_WS2008) ||
1371                 (vmbus_proto_version == VERSION_WIN7)) {
1372
1373                 /* Since we are a child, we only need to check bit 0 */
1374                 if (sync_test_and_clear_bit(0, event->flags))
1375                         handled = true;
1376         } else {
1377                 /*
1378                  * Our host is win8 or above. The signaling mechanism
1379                  * has changed and we can directly look at the event page.
1380                  * If bit n is set then we have an interrup on the channel
1381                  * whose id is n.
1382                  */
1383                 handled = true;
1384         }
1385
1386         if (handled)
1387                 vmbus_chan_sched(hv_cpu);
1388
1389         page_addr = hv_cpu->synic_message_page;
1390         msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
1391
1392         /* Check if there are actual msgs to be processed */
1393         if (msg->header.message_type != HVMSG_NONE) {
1394                 if (msg->header.message_type == HVMSG_TIMER_EXPIRED) {
1395                         hv_stimer0_isr();
1396                         vmbus_signal_eom(msg, HVMSG_TIMER_EXPIRED);
1397                 } else
1398                         tasklet_schedule(&hv_cpu->msg_dpc);
1399         }
1400
1401         add_interrupt_randomness(vmbus_interrupt);
1402 }
1403
1404 static irqreturn_t vmbus_percpu_isr(int irq, void *dev_id)
1405 {
1406         vmbus_isr();
1407         return IRQ_HANDLED;
1408 }
1409
1410 /*
1411  * Callback from kmsg_dump. Grab as much as possible from the end of the kmsg
1412  * buffer and call into Hyper-V to transfer the data.
1413  */
1414 static void hv_kmsg_dump(struct kmsg_dumper *dumper,
1415                          enum kmsg_dump_reason reason)
1416 {
1417         struct kmsg_dump_iter iter;
1418         size_t bytes_written;
1419
1420         /* We are only interested in panics. */
1421         if ((reason != KMSG_DUMP_PANIC) || (!sysctl_record_panic_msg))
1422                 return;
1423
1424         /*
1425          * Write dump contents to the page. No need to synchronize; panic should
1426          * be single-threaded.
1427          */
1428         kmsg_dump_rewind(&iter);
1429         kmsg_dump_get_buffer(&iter, false, hv_panic_page, HV_HYP_PAGE_SIZE,
1430                              &bytes_written);
1431         if (!bytes_written)
1432                 return;
1433         /*
1434          * P3 to contain the physical address of the panic page & P4 to
1435          * contain the size of the panic data in that page. Rest of the
1436          * registers are no-op when the NOTIFY_MSG flag is set.
1437          */
1438         hv_set_register(HV_REGISTER_CRASH_P0, 0);
1439         hv_set_register(HV_REGISTER_CRASH_P1, 0);
1440         hv_set_register(HV_REGISTER_CRASH_P2, 0);
1441         hv_set_register(HV_REGISTER_CRASH_P3, virt_to_phys(hv_panic_page));
1442         hv_set_register(HV_REGISTER_CRASH_P4, bytes_written);
1443
1444         /*
1445          * Let Hyper-V know there is crash data available along with
1446          * the panic message.
1447          */
1448         hv_set_register(HV_REGISTER_CRASH_CTL,
1449                (HV_CRASH_CTL_CRASH_NOTIFY | HV_CRASH_CTL_CRASH_NOTIFY_MSG));
1450 }
1451
1452 static struct kmsg_dumper hv_kmsg_dumper = {
1453         .dump = hv_kmsg_dump,
1454 };
1455
1456 static void hv_kmsg_dump_register(void)
1457 {
1458         int ret;
1459
1460         hv_panic_page = hv_alloc_hyperv_zeroed_page();
1461         if (!hv_panic_page) {
1462                 pr_err("Hyper-V: panic message page memory allocation failed\n");
1463                 return;
1464         }
1465
1466         ret = kmsg_dump_register(&hv_kmsg_dumper);
1467         if (ret) {
1468                 pr_err("Hyper-V: kmsg dump register error 0x%x\n", ret);
1469                 hv_free_hyperv_page((unsigned long)hv_panic_page);
1470                 hv_panic_page = NULL;
1471         }
1472 }
1473
1474 static struct ctl_table_header *hv_ctl_table_hdr;
1475
1476 /*
1477  * sysctl option to allow the user to control whether kmsg data should be
1478  * reported to Hyper-V on panic.
1479  */
1480 static struct ctl_table hv_ctl_table[] = {
1481         {
1482                 .procname       = "hyperv_record_panic_msg",
1483                 .data           = &sysctl_record_panic_msg,
1484                 .maxlen         = sizeof(int),
1485                 .mode           = 0644,
1486                 .proc_handler   = proc_dointvec_minmax,
1487                 .extra1         = SYSCTL_ZERO,
1488                 .extra2         = SYSCTL_ONE
1489         },
1490         {}
1491 };
1492
1493 static struct ctl_table hv_root_table[] = {
1494         {
1495                 .procname       = "kernel",
1496                 .mode           = 0555,
1497                 .child          = hv_ctl_table
1498         },
1499         {}
1500 };
1501
1502 /*
1503  * vmbus_bus_init -Main vmbus driver initialization routine.
1504  *
1505  * Here, we
1506  *      - initialize the vmbus driver context
1507  *      - invoke the vmbus hv main init routine
1508  *      - retrieve the channel offers
1509  */
1510 static int vmbus_bus_init(void)
1511 {
1512         int ret;
1513
1514         ret = hv_init();
1515         if (ret != 0) {
1516                 pr_err("Unable to initialize the hypervisor - 0x%x\n", ret);
1517                 return ret;
1518         }
1519
1520         ret = bus_register(&hv_bus);
1521         if (ret)
1522                 return ret;
1523
1524         /*
1525          * VMbus interrupts are best modeled as per-cpu interrupts. If
1526          * on an architecture with support for per-cpu IRQs (e.g. ARM64),
1527          * allocate a per-cpu IRQ using standard Linux kernel functionality.
1528          * If not on such an architecture (e.g., x86/x64), then rely on
1529          * code in the arch-specific portion of the code tree to connect
1530          * the VMbus interrupt handler.
1531          */
1532
1533         if (vmbus_irq == -1) {
1534                 hv_setup_vmbus_handler(vmbus_isr);
1535         } else {
1536                 vmbus_evt = alloc_percpu(long);
1537                 ret = request_percpu_irq(vmbus_irq, vmbus_percpu_isr,
1538                                 "Hyper-V VMbus", vmbus_evt);
1539                 if (ret) {
1540                         pr_err("Can't request Hyper-V VMbus IRQ %d, Err %d",
1541                                         vmbus_irq, ret);
1542                         free_percpu(vmbus_evt);
1543                         goto err_setup;
1544                 }
1545         }
1546
1547         ret = hv_synic_alloc();
1548         if (ret)
1549                 goto err_alloc;
1550
1551         /*
1552          * Initialize the per-cpu interrupt state and stimer state.
1553          * Then connect to the host.
1554          */
1555         ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "hyperv/vmbus:online",
1556                                 hv_synic_init, hv_synic_cleanup);
1557         if (ret < 0)
1558                 goto err_cpuhp;
1559         hyperv_cpuhp_online = ret;
1560
1561         ret = vmbus_connect();
1562         if (ret)
1563                 goto err_connect;
1564
1565         if (hv_is_isolation_supported())
1566                 sysctl_record_panic_msg = 0;
1567
1568         /*
1569          * Only register if the crash MSRs are available
1570          */
1571         if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
1572                 u64 hyperv_crash_ctl;
1573                 /*
1574                  * Panic message recording (sysctl_record_panic_msg)
1575                  * is enabled by default in non-isolated guests and
1576                  * disabled by default in isolated guests; the panic
1577                  * message recording won't be available in isolated
1578                  * guests should the following registration fail.
1579                  */
1580                 hv_ctl_table_hdr = register_sysctl_table(hv_root_table);
1581                 if (!hv_ctl_table_hdr)
1582                         pr_err("Hyper-V: sysctl table register error");
1583
1584                 /*
1585                  * Register for panic kmsg callback only if the right
1586                  * capability is supported by the hypervisor.
1587                  */
1588                 hyperv_crash_ctl = hv_get_register(HV_REGISTER_CRASH_CTL);
1589                 if (hyperv_crash_ctl & HV_CRASH_CTL_CRASH_NOTIFY_MSG)
1590                         hv_kmsg_dump_register();
1591
1592                 register_die_notifier(&hyperv_die_block);
1593         }
1594
1595         /*
1596          * Always register the panic notifier because we need to unload
1597          * the VMbus channel connection to prevent any VMbus
1598          * activity after the VM panics.
1599          */
1600         atomic_notifier_chain_register(&panic_notifier_list,
1601                                &hyperv_panic_block);
1602
1603         vmbus_request_offers();
1604
1605         return 0;
1606
1607 err_connect:
1608         cpuhp_remove_state(hyperv_cpuhp_online);
1609 err_cpuhp:
1610         hv_synic_free();
1611 err_alloc:
1612         if (vmbus_irq == -1) {
1613                 hv_remove_vmbus_handler();
1614         } else {
1615                 free_percpu_irq(vmbus_irq, vmbus_evt);
1616                 free_percpu(vmbus_evt);
1617         }
1618 err_setup:
1619         bus_unregister(&hv_bus);
1620         unregister_sysctl_table(hv_ctl_table_hdr);
1621         hv_ctl_table_hdr = NULL;
1622         return ret;
1623 }
1624
1625 /**
1626  * __vmbus_child_driver_register() - Register a vmbus's driver
1627  * @hv_driver: Pointer to driver structure you want to register
1628  * @owner: owner module of the drv
1629  * @mod_name: module name string
1630  *
1631  * Registers the given driver with Linux through the 'driver_register()' call
1632  * and sets up the hyper-v vmbus handling for this driver.
1633  * It will return the state of the 'driver_register()' call.
1634  *
1635  */
1636 int __vmbus_driver_register(struct hv_driver *hv_driver, struct module *owner, const char *mod_name)
1637 {
1638         int ret;
1639
1640         pr_info("registering driver %s\n", hv_driver->name);
1641
1642         ret = vmbus_exists();
1643         if (ret < 0)
1644                 return ret;
1645
1646         hv_driver->driver.name = hv_driver->name;
1647         hv_driver->driver.owner = owner;
1648         hv_driver->driver.mod_name = mod_name;
1649         hv_driver->driver.bus = &hv_bus;
1650
1651         spin_lock_init(&hv_driver->dynids.lock);
1652         INIT_LIST_HEAD(&hv_driver->dynids.list);
1653
1654         ret = driver_register(&hv_driver->driver);
1655
1656         return ret;
1657 }
1658 EXPORT_SYMBOL_GPL(__vmbus_driver_register);
1659
1660 /**
1661  * vmbus_driver_unregister() - Unregister a vmbus's driver
1662  * @hv_driver: Pointer to driver structure you want to
1663  *             un-register
1664  *
1665  * Un-register the given driver that was previous registered with a call to
1666  * vmbus_driver_register()
1667  */
1668 void vmbus_driver_unregister(struct hv_driver *hv_driver)
1669 {
1670         pr_info("unregistering driver %s\n", hv_driver->name);
1671
1672         if (!vmbus_exists()) {
1673                 driver_unregister(&hv_driver->driver);
1674                 vmbus_free_dynids(hv_driver);
1675         }
1676 }
1677 EXPORT_SYMBOL_GPL(vmbus_driver_unregister);
1678
1679
1680 /*
1681  * Called when last reference to channel is gone.
1682  */
1683 static void vmbus_chan_release(struct kobject *kobj)
1684 {
1685         struct vmbus_channel *channel
1686                 = container_of(kobj, struct vmbus_channel, kobj);
1687
1688         kfree_rcu(channel, rcu);
1689 }
1690
1691 struct vmbus_chan_attribute {
1692         struct attribute attr;
1693         ssize_t (*show)(struct vmbus_channel *chan, char *buf);
1694         ssize_t (*store)(struct vmbus_channel *chan,
1695                          const char *buf, size_t count);
1696 };
1697 #define VMBUS_CHAN_ATTR(_name, _mode, _show, _store) \
1698         struct vmbus_chan_attribute chan_attr_##_name \
1699                 = __ATTR(_name, _mode, _show, _store)
1700 #define VMBUS_CHAN_ATTR_RW(_name) \
1701         struct vmbus_chan_attribute chan_attr_##_name = __ATTR_RW(_name)
1702 #define VMBUS_CHAN_ATTR_RO(_name) \
1703         struct vmbus_chan_attribute chan_attr_##_name = __ATTR_RO(_name)
1704 #define VMBUS_CHAN_ATTR_WO(_name) \
1705         struct vmbus_chan_attribute chan_attr_##_name = __ATTR_WO(_name)
1706
1707 static ssize_t vmbus_chan_attr_show(struct kobject *kobj,
1708                                     struct attribute *attr, char *buf)
1709 {
1710         const struct vmbus_chan_attribute *attribute
1711                 = container_of(attr, struct vmbus_chan_attribute, attr);
1712         struct vmbus_channel *chan
1713                 = container_of(kobj, struct vmbus_channel, kobj);
1714
1715         if (!attribute->show)
1716                 return -EIO;
1717
1718         return attribute->show(chan, buf);
1719 }
1720
1721 static ssize_t vmbus_chan_attr_store(struct kobject *kobj,
1722                                      struct attribute *attr, const char *buf,
1723                                      size_t count)
1724 {
1725         const struct vmbus_chan_attribute *attribute
1726                 = container_of(attr, struct vmbus_chan_attribute, attr);
1727         struct vmbus_channel *chan
1728                 = container_of(kobj, struct vmbus_channel, kobj);
1729
1730         if (!attribute->store)
1731                 return -EIO;
1732
1733         return attribute->store(chan, buf, count);
1734 }
1735
1736 static const struct sysfs_ops vmbus_chan_sysfs_ops = {
1737         .show = vmbus_chan_attr_show,
1738         .store = vmbus_chan_attr_store,
1739 };
1740
1741 static ssize_t out_mask_show(struct vmbus_channel *channel, char *buf)
1742 {
1743         struct hv_ring_buffer_info *rbi = &channel->outbound;
1744         ssize_t ret;
1745
1746         mutex_lock(&rbi->ring_buffer_mutex);
1747         if (!rbi->ring_buffer) {
1748                 mutex_unlock(&rbi->ring_buffer_mutex);
1749                 return -EINVAL;
1750         }
1751
1752         ret = sprintf(buf, "%u\n", rbi->ring_buffer->interrupt_mask);
1753         mutex_unlock(&rbi->ring_buffer_mutex);
1754         return ret;
1755 }
1756 static VMBUS_CHAN_ATTR_RO(out_mask);
1757
1758 static ssize_t in_mask_show(struct vmbus_channel *channel, char *buf)
1759 {
1760         struct hv_ring_buffer_info *rbi = &channel->inbound;
1761         ssize_t ret;
1762
1763         mutex_lock(&rbi->ring_buffer_mutex);
1764         if (!rbi->ring_buffer) {
1765                 mutex_unlock(&rbi->ring_buffer_mutex);
1766                 return -EINVAL;
1767         }
1768
1769         ret = sprintf(buf, "%u\n", rbi->ring_buffer->interrupt_mask);
1770         mutex_unlock(&rbi->ring_buffer_mutex);
1771         return ret;
1772 }
1773 static VMBUS_CHAN_ATTR_RO(in_mask);
1774
1775 static ssize_t read_avail_show(struct vmbus_channel *channel, char *buf)
1776 {
1777         struct hv_ring_buffer_info *rbi = &channel->inbound;
1778         ssize_t ret;
1779
1780         mutex_lock(&rbi->ring_buffer_mutex);
1781         if (!rbi->ring_buffer) {
1782                 mutex_unlock(&rbi->ring_buffer_mutex);
1783                 return -EINVAL;
1784         }
1785
1786         ret = sprintf(buf, "%u\n", hv_get_bytes_to_read(rbi));
1787         mutex_unlock(&rbi->ring_buffer_mutex);
1788         return ret;
1789 }
1790 static VMBUS_CHAN_ATTR_RO(read_avail);
1791
1792 static ssize_t write_avail_show(struct vmbus_channel *channel, char *buf)
1793 {
1794         struct hv_ring_buffer_info *rbi = &channel->outbound;
1795         ssize_t ret;
1796
1797         mutex_lock(&rbi->ring_buffer_mutex);
1798         if (!rbi->ring_buffer) {
1799                 mutex_unlock(&rbi->ring_buffer_mutex);
1800                 return -EINVAL;
1801         }
1802
1803         ret = sprintf(buf, "%u\n", hv_get_bytes_to_write(rbi));
1804         mutex_unlock(&rbi->ring_buffer_mutex);
1805         return ret;
1806 }
1807 static VMBUS_CHAN_ATTR_RO(write_avail);
1808
1809 static ssize_t target_cpu_show(struct vmbus_channel *channel, char *buf)
1810 {
1811         return sprintf(buf, "%u\n", channel->target_cpu);
1812 }
1813 static ssize_t target_cpu_store(struct vmbus_channel *channel,
1814                                 const char *buf, size_t count)
1815 {
1816         u32 target_cpu, origin_cpu;
1817         ssize_t ret = count;
1818
1819         if (vmbus_proto_version < VERSION_WIN10_V4_1)
1820                 return -EIO;
1821
1822         if (sscanf(buf, "%uu", &target_cpu) != 1)
1823                 return -EIO;
1824
1825         /* Validate target_cpu for the cpumask_test_cpu() operation below. */
1826         if (target_cpu >= nr_cpumask_bits)
1827                 return -EINVAL;
1828
1829         /* No CPUs should come up or down during this. */
1830         cpus_read_lock();
1831
1832         if (!cpu_online(target_cpu)) {
1833                 cpus_read_unlock();
1834                 return -EINVAL;
1835         }
1836
1837         /*
1838          * Synchronizes target_cpu_store() and channel closure:
1839          *
1840          * { Initially: state = CHANNEL_OPENED }
1841          *
1842          * CPU1                         CPU2
1843          *
1844          * [target_cpu_store()]         [vmbus_disconnect_ring()]
1845          *
1846          * LOCK channel_mutex           LOCK channel_mutex
1847          * LOAD r1 = state              LOAD r2 = state
1848          * IF (r1 == CHANNEL_OPENED)    IF (r2 == CHANNEL_OPENED)
1849          *   SEND MODIFYCHANNEL           STORE state = CHANNEL_OPEN
1850          *   [...]                        SEND CLOSECHANNEL
1851          * UNLOCK channel_mutex         UNLOCK channel_mutex
1852          *
1853          * Forbids: r1 == r2 == CHANNEL_OPENED (i.e., CPU1's LOCK precedes
1854          *              CPU2's LOCK) && CPU2's SEND precedes CPU1's SEND
1855          *
1856          * Note.  The host processes the channel messages "sequentially", in
1857          * the order in which they are received on a per-partition basis.
1858          */
1859         mutex_lock(&vmbus_connection.channel_mutex);
1860
1861         /*
1862          * Hyper-V will ignore MODIFYCHANNEL messages for "non-open" channels;
1863          * avoid sending the message and fail here for such channels.
1864          */
1865         if (channel->state != CHANNEL_OPENED_STATE) {
1866                 ret = -EIO;
1867                 goto cpu_store_unlock;
1868         }
1869
1870         origin_cpu = channel->target_cpu;
1871         if (target_cpu == origin_cpu)
1872                 goto cpu_store_unlock;
1873
1874         if (vmbus_send_modifychannel(channel,
1875                                      hv_cpu_number_to_vp_number(target_cpu))) {
1876                 ret = -EIO;
1877                 goto cpu_store_unlock;
1878         }
1879
1880         /*
1881          * For version before VERSION_WIN10_V5_3, the following warning holds:
1882          *
1883          * Warning.  At this point, there is *no* guarantee that the host will
1884          * have successfully processed the vmbus_send_modifychannel() request.
1885          * See the header comment of vmbus_send_modifychannel() for more info.
1886          *
1887          * Lags in the processing of the above vmbus_send_modifychannel() can
1888          * result in missed interrupts if the "old" target CPU is taken offline
1889          * before Hyper-V starts sending interrupts to the "new" target CPU.
1890          * But apart from this offlining scenario, the code tolerates such
1891          * lags.  It will function correctly even if a channel interrupt comes
1892          * in on a CPU that is different from the channel target_cpu value.
1893          */
1894
1895         channel->target_cpu = target_cpu;
1896
1897         /* See init_vp_index(). */
1898         if (hv_is_perf_channel(channel))
1899                 hv_update_allocated_cpus(origin_cpu, target_cpu);
1900
1901         /* Currently set only for storvsc channels. */
1902         if (channel->change_target_cpu_callback) {
1903                 (*channel->change_target_cpu_callback)(channel,
1904                                 origin_cpu, target_cpu);
1905         }
1906
1907 cpu_store_unlock:
1908         mutex_unlock(&vmbus_connection.channel_mutex);
1909         cpus_read_unlock();
1910         return ret;
1911 }
1912 static VMBUS_CHAN_ATTR(cpu, 0644, target_cpu_show, target_cpu_store);
1913
1914 static ssize_t channel_pending_show(struct vmbus_channel *channel,
1915                                     char *buf)
1916 {
1917         return sprintf(buf, "%d\n",
1918                        channel_pending(channel,
1919                                        vmbus_connection.monitor_pages[1]));
1920 }
1921 static VMBUS_CHAN_ATTR(pending, 0444, channel_pending_show, NULL);
1922
1923 static ssize_t channel_latency_show(struct vmbus_channel *channel,
1924                                     char *buf)
1925 {
1926         return sprintf(buf, "%d\n",
1927                        channel_latency(channel,
1928                                        vmbus_connection.monitor_pages[1]));
1929 }
1930 static VMBUS_CHAN_ATTR(latency, 0444, channel_latency_show, NULL);
1931
1932 static ssize_t channel_interrupts_show(struct vmbus_channel *channel, char *buf)
1933 {
1934         return sprintf(buf, "%llu\n", channel->interrupts);
1935 }
1936 static VMBUS_CHAN_ATTR(interrupts, 0444, channel_interrupts_show, NULL);
1937
1938 static ssize_t channel_events_show(struct vmbus_channel *channel, char *buf)
1939 {
1940         return sprintf(buf, "%llu\n", channel->sig_events);
1941 }
1942 static VMBUS_CHAN_ATTR(events, 0444, channel_events_show, NULL);
1943
1944 static ssize_t channel_intr_in_full_show(struct vmbus_channel *channel,
1945                                          char *buf)
1946 {
1947         return sprintf(buf, "%llu\n",
1948                        (unsigned long long)channel->intr_in_full);
1949 }
1950 static VMBUS_CHAN_ATTR(intr_in_full, 0444, channel_intr_in_full_show, NULL);
1951
1952 static ssize_t channel_intr_out_empty_show(struct vmbus_channel *channel,
1953                                            char *buf)
1954 {
1955         return sprintf(buf, "%llu\n",
1956                        (unsigned long long)channel->intr_out_empty);
1957 }
1958 static VMBUS_CHAN_ATTR(intr_out_empty, 0444, channel_intr_out_empty_show, NULL);
1959
1960 static ssize_t channel_out_full_first_show(struct vmbus_channel *channel,
1961                                            char *buf)
1962 {
1963         return sprintf(buf, "%llu\n",
1964                        (unsigned long long)channel->out_full_first);
1965 }
1966 static VMBUS_CHAN_ATTR(out_full_first, 0444, channel_out_full_first_show, NULL);
1967
1968 static ssize_t channel_out_full_total_show(struct vmbus_channel *channel,
1969                                            char *buf)
1970 {
1971         return sprintf(buf, "%llu\n",
1972                        (unsigned long long)channel->out_full_total);
1973 }
1974 static VMBUS_CHAN_ATTR(out_full_total, 0444, channel_out_full_total_show, NULL);
1975
1976 static ssize_t subchannel_monitor_id_show(struct vmbus_channel *channel,
1977                                           char *buf)
1978 {
1979         return sprintf(buf, "%u\n", channel->offermsg.monitorid);
1980 }
1981 static VMBUS_CHAN_ATTR(monitor_id, 0444, subchannel_monitor_id_show, NULL);
1982
1983 static ssize_t subchannel_id_show(struct vmbus_channel *channel,
1984                                   char *buf)
1985 {
1986         return sprintf(buf, "%u\n",
1987                        channel->offermsg.offer.sub_channel_index);
1988 }
1989 static VMBUS_CHAN_ATTR_RO(subchannel_id);
1990
1991 static struct attribute *vmbus_chan_attrs[] = {
1992         &chan_attr_out_mask.attr,
1993         &chan_attr_in_mask.attr,
1994         &chan_attr_read_avail.attr,
1995         &chan_attr_write_avail.attr,
1996         &chan_attr_cpu.attr,
1997         &chan_attr_pending.attr,
1998         &chan_attr_latency.attr,
1999         &chan_attr_interrupts.attr,
2000         &chan_attr_events.attr,
2001         &chan_attr_intr_in_full.attr,
2002         &chan_attr_intr_out_empty.attr,
2003         &chan_attr_out_full_first.attr,
2004         &chan_attr_out_full_total.attr,
2005         &chan_attr_monitor_id.attr,
2006         &chan_attr_subchannel_id.attr,
2007         NULL
2008 };
2009
2010 /*
2011  * Channel-level attribute_group callback function. Returns the permission for
2012  * each attribute, and returns 0 if an attribute is not visible.
2013  */
2014 static umode_t vmbus_chan_attr_is_visible(struct kobject *kobj,
2015                                           struct attribute *attr, int idx)
2016 {
2017         const struct vmbus_channel *channel =
2018                 container_of(kobj, struct vmbus_channel, kobj);
2019
2020         /* Hide the monitor attributes if the monitor mechanism is not used. */
2021         if (!channel->offermsg.monitor_allocated &&
2022             (attr == &chan_attr_pending.attr ||
2023              attr == &chan_attr_latency.attr ||
2024              attr == &chan_attr_monitor_id.attr))
2025                 return 0;
2026
2027         return attr->mode;
2028 }
2029
2030 static struct attribute_group vmbus_chan_group = {
2031         .attrs = vmbus_chan_attrs,
2032         .is_visible = vmbus_chan_attr_is_visible
2033 };
2034
2035 static struct kobj_type vmbus_chan_ktype = {
2036         .sysfs_ops = &vmbus_chan_sysfs_ops,
2037         .release = vmbus_chan_release,
2038 };
2039
2040 /*
2041  * vmbus_add_channel_kobj - setup a sub-directory under device/channels
2042  */
2043 int vmbus_add_channel_kobj(struct hv_device *dev, struct vmbus_channel *channel)
2044 {
2045         const struct device *device = &dev->device;
2046         struct kobject *kobj = &channel->kobj;
2047         u32 relid = channel->offermsg.child_relid;
2048         int ret;
2049
2050         kobj->kset = dev->channels_kset;
2051         ret = kobject_init_and_add(kobj, &vmbus_chan_ktype, NULL,
2052                                    "%u", relid);
2053         if (ret) {
2054                 kobject_put(kobj);
2055                 return ret;
2056         }
2057
2058         ret = sysfs_create_group(kobj, &vmbus_chan_group);
2059
2060         if (ret) {
2061                 /*
2062                  * The calling functions' error handling paths will cleanup the
2063                  * empty channel directory.
2064                  */
2065                 kobject_put(kobj);
2066                 dev_err(device, "Unable to set up channel sysfs files\n");
2067                 return ret;
2068         }
2069
2070         kobject_uevent(kobj, KOBJ_ADD);
2071
2072         return 0;
2073 }
2074
2075 /*
2076  * vmbus_remove_channel_attr_group - remove the channel's attribute group
2077  */
2078 void vmbus_remove_channel_attr_group(struct vmbus_channel *channel)
2079 {
2080         sysfs_remove_group(&channel->kobj, &vmbus_chan_group);
2081 }
2082
2083 /*
2084  * vmbus_device_create - Creates and registers a new child device
2085  * on the vmbus.
2086  */
2087 struct hv_device *vmbus_device_create(const guid_t *type,
2088                                       const guid_t *instance,
2089                                       struct vmbus_channel *channel)
2090 {
2091         struct hv_device *child_device_obj;
2092
2093         child_device_obj = kzalloc(sizeof(struct hv_device), GFP_KERNEL);
2094         if (!child_device_obj) {
2095                 pr_err("Unable to allocate device object for child device\n");
2096                 return NULL;
2097         }
2098
2099         child_device_obj->channel = channel;
2100         guid_copy(&child_device_obj->dev_type, type);
2101         guid_copy(&child_device_obj->dev_instance, instance);
2102         child_device_obj->vendor_id = 0x1414; /* MSFT vendor ID */
2103
2104         return child_device_obj;
2105 }
2106
2107 /*
2108  * vmbus_device_register - Register the child device
2109  */
2110 int vmbus_device_register(struct hv_device *child_device_obj)
2111 {
2112         struct kobject *kobj = &child_device_obj->device.kobj;
2113         int ret;
2114
2115         dev_set_name(&child_device_obj->device, "%pUl",
2116                      &child_device_obj->channel->offermsg.offer.if_instance);
2117
2118         child_device_obj->device.bus = &hv_bus;
2119         child_device_obj->device.parent = &hv_acpi_dev->dev;
2120         child_device_obj->device.release = vmbus_device_release;
2121
2122         child_device_obj->device.dma_parms = &child_device_obj->dma_parms;
2123         child_device_obj->device.dma_mask = &child_device_obj->dma_mask;
2124         dma_set_mask(&child_device_obj->device, DMA_BIT_MASK(64));
2125
2126         /*
2127          * Register with the LDM. This will kick off the driver/device
2128          * binding...which will eventually call vmbus_match() and vmbus_probe()
2129          */
2130         ret = device_register(&child_device_obj->device);
2131         if (ret) {
2132                 pr_err("Unable to register child device\n");
2133                 return ret;
2134         }
2135
2136         child_device_obj->channels_kset = kset_create_and_add("channels",
2137                                                               NULL, kobj);
2138         if (!child_device_obj->channels_kset) {
2139                 ret = -ENOMEM;
2140                 goto err_dev_unregister;
2141         }
2142
2143         ret = vmbus_add_channel_kobj(child_device_obj,
2144                                      child_device_obj->channel);
2145         if (ret) {
2146                 pr_err("Unable to register primary channeln");
2147                 goto err_kset_unregister;
2148         }
2149         hv_debug_add_dev_dir(child_device_obj);
2150
2151         return 0;
2152
2153 err_kset_unregister:
2154         kset_unregister(child_device_obj->channels_kset);
2155
2156 err_dev_unregister:
2157         device_unregister(&child_device_obj->device);
2158         return ret;
2159 }
2160
2161 /*
2162  * vmbus_device_unregister - Remove the specified child device
2163  * from the vmbus.
2164  */
2165 void vmbus_device_unregister(struct hv_device *device_obj)
2166 {
2167         pr_debug("child device %s unregistered\n",
2168                 dev_name(&device_obj->device));
2169
2170         kset_unregister(device_obj->channels_kset);
2171
2172         /*
2173          * Kick off the process of unregistering the device.
2174          * This will call vmbus_remove() and eventually vmbus_device_release()
2175          */
2176         device_unregister(&device_obj->device);
2177 }
2178
2179
2180 /*
2181  * VMBUS is an acpi enumerated device. Get the information we
2182  * need from DSDT.
2183  */
2184 #define VTPM_BASE_ADDRESS 0xfed40000
2185 static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *ctx)
2186 {
2187         resource_size_t start = 0;
2188         resource_size_t end = 0;
2189         struct resource *new_res;
2190         struct resource **old_res = &hyperv_mmio;
2191         struct resource **prev_res = NULL;
2192         struct resource r;
2193
2194         switch (res->type) {
2195
2196         /*
2197          * "Address" descriptors are for bus windows. Ignore
2198          * "memory" descriptors, which are for registers on
2199          * devices.
2200          */
2201         case ACPI_RESOURCE_TYPE_ADDRESS32:
2202                 start = res->data.address32.address.minimum;
2203                 end = res->data.address32.address.maximum;
2204                 break;
2205
2206         case ACPI_RESOURCE_TYPE_ADDRESS64:
2207                 start = res->data.address64.address.minimum;
2208                 end = res->data.address64.address.maximum;
2209                 break;
2210
2211         /*
2212          * The IRQ information is needed only on ARM64, which Hyper-V
2213          * sets up in the extended format. IRQ information is present
2214          * on x86/x64 in the non-extended format but it is not used by
2215          * Linux. So don't bother checking for the non-extended format.
2216          */
2217         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
2218                 if (!acpi_dev_resource_interrupt(res, 0, &r)) {
2219                         pr_err("Unable to parse Hyper-V ACPI interrupt\n");
2220                         return AE_ERROR;
2221                 }
2222                 /* ARM64 INTID for VMbus */
2223                 vmbus_interrupt = res->data.extended_irq.interrupts[0];
2224                 /* Linux IRQ number */
2225                 vmbus_irq = r.start;
2226                 return AE_OK;
2227
2228         default:
2229                 /* Unused resource type */
2230                 return AE_OK;
2231
2232         }
2233         /*
2234          * Ignore ranges that are below 1MB, as they're not
2235          * necessary or useful here.
2236          */
2237         if (end < 0x100000)
2238                 return AE_OK;
2239
2240         new_res = kzalloc(sizeof(*new_res), GFP_ATOMIC);
2241         if (!new_res)
2242                 return AE_NO_MEMORY;
2243
2244         /* If this range overlaps the virtual TPM, truncate it. */
2245         if (end > VTPM_BASE_ADDRESS && start < VTPM_BASE_ADDRESS)
2246                 end = VTPM_BASE_ADDRESS;
2247
2248         new_res->name = "hyperv mmio";
2249         new_res->flags = IORESOURCE_MEM;
2250         new_res->start = start;
2251         new_res->end = end;
2252
2253         /*
2254          * If two ranges are adjacent, merge them.
2255          */
2256         do {
2257                 if (!*old_res) {
2258                         *old_res = new_res;
2259                         break;
2260                 }
2261
2262                 if (((*old_res)->end + 1) == new_res->start) {
2263                         (*old_res)->end = new_res->end;
2264                         kfree(new_res);
2265                         break;
2266                 }
2267
2268                 if ((*old_res)->start == new_res->end + 1) {
2269                         (*old_res)->start = new_res->start;
2270                         kfree(new_res);
2271                         break;
2272                 }
2273
2274                 if ((*old_res)->start > new_res->end) {
2275                         new_res->sibling = *old_res;
2276                         if (prev_res)
2277                                 (*prev_res)->sibling = new_res;
2278                         *old_res = new_res;
2279                         break;
2280                 }
2281
2282                 prev_res = old_res;
2283                 old_res = &(*old_res)->sibling;
2284
2285         } while (1);
2286
2287         return AE_OK;
2288 }
2289
2290 static int vmbus_acpi_remove(struct acpi_device *device)
2291 {
2292         struct resource *cur_res;
2293         struct resource *next_res;
2294
2295         if (hyperv_mmio) {
2296                 if (fb_mmio) {
2297                         __release_region(hyperv_mmio, fb_mmio->start,
2298                                          resource_size(fb_mmio));
2299                         fb_mmio = NULL;
2300                 }
2301
2302                 for (cur_res = hyperv_mmio; cur_res; cur_res = next_res) {
2303                         next_res = cur_res->sibling;
2304                         kfree(cur_res);
2305                 }
2306         }
2307
2308         return 0;
2309 }
2310
2311 static void vmbus_reserve_fb(void)
2312 {
2313         int size;
2314         /*
2315          * Make a claim for the frame buffer in the resource tree under the
2316          * first node, which will be the one below 4GB.  The length seems to
2317          * be underreported, particularly in a Generation 1 VM.  So start out
2318          * reserving a larger area and make it smaller until it succeeds.
2319          */
2320
2321         if (screen_info.lfb_base) {
2322                 if (efi_enabled(EFI_BOOT))
2323                         size = max_t(__u32, screen_info.lfb_size, 0x800000);
2324                 else
2325                         size = max_t(__u32, screen_info.lfb_size, 0x4000000);
2326
2327                 for (; !fb_mmio && (size >= 0x100000); size >>= 1) {
2328                         fb_mmio = __request_region(hyperv_mmio,
2329                                                    screen_info.lfb_base, size,
2330                                                    fb_mmio_name, 0);
2331                 }
2332         }
2333 }
2334
2335 /**
2336  * vmbus_allocate_mmio() - Pick a memory-mapped I/O range.
2337  * @new:                If successful, supplied a pointer to the
2338  *                      allocated MMIO space.
2339  * @device_obj:         Identifies the caller
2340  * @min:                Minimum guest physical address of the
2341  *                      allocation
2342  * @max:                Maximum guest physical address
2343  * @size:               Size of the range to be allocated
2344  * @align:              Alignment of the range to be allocated
2345  * @fb_overlap_ok:      Whether this allocation can be allowed
2346  *                      to overlap the video frame buffer.
2347  *
2348  * This function walks the resources granted to VMBus by the
2349  * _CRS object in the ACPI namespace underneath the parent
2350  * "bridge" whether that's a root PCI bus in the Generation 1
2351  * case or a Module Device in the Generation 2 case.  It then
2352  * attempts to allocate from the global MMIO pool in a way that
2353  * matches the constraints supplied in these parameters and by
2354  * that _CRS.
2355  *
2356  * Return: 0 on success, -errno on failure
2357  */
2358 int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
2359                         resource_size_t min, resource_size_t max,
2360                         resource_size_t size, resource_size_t align,
2361                         bool fb_overlap_ok)
2362 {
2363         struct resource *iter, *shadow;
2364         resource_size_t range_min, range_max, start;
2365         const char *dev_n = dev_name(&device_obj->device);
2366         int retval;
2367
2368         retval = -ENXIO;
2369         mutex_lock(&hyperv_mmio_lock);
2370
2371         /*
2372          * If overlaps with frame buffers are allowed, then first attempt to
2373          * make the allocation from within the reserved region.  Because it
2374          * is already reserved, no shadow allocation is necessary.
2375          */
2376         if (fb_overlap_ok && fb_mmio && !(min > fb_mmio->end) &&
2377             !(max < fb_mmio->start)) {
2378
2379                 range_min = fb_mmio->start;
2380                 range_max = fb_mmio->end;
2381                 start = (range_min + align - 1) & ~(align - 1);
2382                 for (; start + size - 1 <= range_max; start += align) {
2383                         *new = request_mem_region_exclusive(start, size, dev_n);
2384                         if (*new) {
2385                                 retval = 0;
2386                                 goto exit;
2387                         }
2388                 }
2389         }
2390
2391         for (iter = hyperv_mmio; iter; iter = iter->sibling) {
2392                 if ((iter->start >= max) || (iter->end <= min))
2393                         continue;
2394
2395                 range_min = iter->start;
2396                 range_max = iter->end;
2397                 start = (range_min + align - 1) & ~(align - 1);
2398                 for (; start + size - 1 <= range_max; start += align) {
2399                         shadow = __request_region(iter, start, size, NULL,
2400                                                   IORESOURCE_BUSY);
2401                         if (!shadow)
2402                                 continue;
2403
2404                         *new = request_mem_region_exclusive(start, size, dev_n);
2405                         if (*new) {
2406                                 shadow->name = (char *)*new;
2407                                 retval = 0;
2408                                 goto exit;
2409                         }
2410
2411                         __release_region(iter, start, size);
2412                 }
2413         }
2414
2415 exit:
2416         mutex_unlock(&hyperv_mmio_lock);
2417         return retval;
2418 }
2419 EXPORT_SYMBOL_GPL(vmbus_allocate_mmio);
2420
2421 /**
2422  * vmbus_free_mmio() - Free a memory-mapped I/O range.
2423  * @start:              Base address of region to release.
2424  * @size:               Size of the range to be allocated
2425  *
2426  * This function releases anything requested by
2427  * vmbus_mmio_allocate().
2428  */
2429 void vmbus_free_mmio(resource_size_t start, resource_size_t size)
2430 {
2431         struct resource *iter;
2432
2433         mutex_lock(&hyperv_mmio_lock);
2434         for (iter = hyperv_mmio; iter; iter = iter->sibling) {
2435                 if ((iter->start >= start + size) || (iter->end <= start))
2436                         continue;
2437
2438                 __release_region(iter, start, size);
2439         }
2440         release_mem_region(start, size);
2441         mutex_unlock(&hyperv_mmio_lock);
2442
2443 }
2444 EXPORT_SYMBOL_GPL(vmbus_free_mmio);
2445
2446 static int vmbus_acpi_add(struct acpi_device *device)
2447 {
2448         acpi_status result;
2449         int ret_val = -ENODEV;
2450         struct acpi_device *ancestor;
2451
2452         hv_acpi_dev = device;
2453
2454         /*
2455          * Older versions of Hyper-V for ARM64 fail to include the _CCA
2456          * method on the top level VMbus device in the DSDT. But devices
2457          * are hardware coherent in all current Hyper-V use cases, so fix
2458          * up the ACPI device to behave as if _CCA is present and indicates
2459          * hardware coherence.
2460          */
2461         ACPI_COMPANION_SET(&device->dev, device);
2462         if (IS_ENABLED(CONFIG_ACPI_CCA_REQUIRED) &&
2463             device_get_dma_attr(&device->dev) == DEV_DMA_NOT_SUPPORTED) {
2464                 pr_info("No ACPI _CCA found; assuming coherent device I/O\n");
2465                 device->flags.cca_seen = true;
2466                 device->flags.coherent_dma = true;
2467         }
2468
2469         result = acpi_walk_resources(device->handle, METHOD_NAME__CRS,
2470                                         vmbus_walk_resources, NULL);
2471
2472         if (ACPI_FAILURE(result))
2473                 goto acpi_walk_err;
2474         /*
2475          * Some ancestor of the vmbus acpi device (Gen1 or Gen2
2476          * firmware) is the VMOD that has the mmio ranges. Get that.
2477          */
2478         for (ancestor = device->parent; ancestor; ancestor = ancestor->parent) {
2479                 result = acpi_walk_resources(ancestor->handle, METHOD_NAME__CRS,
2480                                              vmbus_walk_resources, NULL);
2481
2482                 if (ACPI_FAILURE(result))
2483                         continue;
2484                 if (hyperv_mmio) {
2485                         vmbus_reserve_fb();
2486                         break;
2487                 }
2488         }
2489         ret_val = 0;
2490
2491 acpi_walk_err:
2492         complete(&probe_event);
2493         if (ret_val)
2494                 vmbus_acpi_remove(device);
2495         return ret_val;
2496 }
2497
2498 #ifdef CONFIG_PM_SLEEP
2499 static int vmbus_bus_suspend(struct device *dev)
2500 {
2501         struct vmbus_channel *channel, *sc;
2502
2503         while (atomic_read(&vmbus_connection.offer_in_progress) != 0) {
2504                 /*
2505                  * We wait here until the completion of any channel
2506                  * offers that are currently in progress.
2507                  */
2508                 usleep_range(1000, 2000);
2509         }
2510
2511         mutex_lock(&vmbus_connection.channel_mutex);
2512         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
2513                 if (!is_hvsock_channel(channel))
2514                         continue;
2515
2516                 vmbus_force_channel_rescinded(channel);
2517         }
2518         mutex_unlock(&vmbus_connection.channel_mutex);
2519
2520         /*
2521          * Wait until all the sub-channels and hv_sock channels have been
2522          * cleaned up. Sub-channels should be destroyed upon suspend, otherwise
2523          * they would conflict with the new sub-channels that will be created
2524          * in the resume path. hv_sock channels should also be destroyed, but
2525          * a hv_sock channel of an established hv_sock connection can not be
2526          * really destroyed since it may still be referenced by the userspace
2527          * application, so we just force the hv_sock channel to be rescinded
2528          * by vmbus_force_channel_rescinded(), and the userspace application
2529          * will thoroughly destroy the channel after hibernation.
2530          *
2531          * Note: the counter nr_chan_close_on_suspend may never go above 0 if
2532          * the VM has no sub-channel and hv_sock channel, e.g. a 1-vCPU VM.
2533          */
2534         if (atomic_read(&vmbus_connection.nr_chan_close_on_suspend) > 0)
2535                 wait_for_completion(&vmbus_connection.ready_for_suspend_event);
2536
2537         if (atomic_read(&vmbus_connection.nr_chan_fixup_on_resume) != 0) {
2538                 pr_err("Can not suspend due to a previous failed resuming\n");
2539                 return -EBUSY;
2540         }
2541
2542         mutex_lock(&vmbus_connection.channel_mutex);
2543
2544         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
2545                 /*
2546                  * Remove the channel from the array of channels and invalidate
2547                  * the channel's relid.  Upon resume, vmbus_onoffer() will fix
2548                  * up the relid (and other fields, if necessary) and add the
2549                  * channel back to the array.
2550                  */
2551                 vmbus_channel_unmap_relid(channel);
2552                 channel->offermsg.child_relid = INVALID_RELID;
2553
2554                 if (is_hvsock_channel(channel)) {
2555                         if (!channel->rescind) {
2556                                 pr_err("hv_sock channel not rescinded!\n");
2557                                 WARN_ON_ONCE(1);
2558                         }
2559                         continue;
2560                 }
2561
2562                 list_for_each_entry(sc, &channel->sc_list, sc_list) {
2563                         pr_err("Sub-channel not deleted!\n");
2564                         WARN_ON_ONCE(1);
2565                 }
2566
2567                 atomic_inc(&vmbus_connection.nr_chan_fixup_on_resume);
2568         }
2569
2570         mutex_unlock(&vmbus_connection.channel_mutex);
2571
2572         vmbus_initiate_unload(false);
2573
2574         /* Reset the event for the next resume. */
2575         reinit_completion(&vmbus_connection.ready_for_resume_event);
2576
2577         return 0;
2578 }
2579
2580 static int vmbus_bus_resume(struct device *dev)
2581 {
2582         struct vmbus_channel_msginfo *msginfo;
2583         size_t msgsize;
2584         int ret;
2585
2586         /*
2587          * We only use the 'vmbus_proto_version', which was in use before
2588          * hibernation, to re-negotiate with the host.
2589          */
2590         if (!vmbus_proto_version) {
2591                 pr_err("Invalid proto version = 0x%x\n", vmbus_proto_version);
2592                 return -EINVAL;
2593         }
2594
2595         msgsize = sizeof(*msginfo) +
2596                   sizeof(struct vmbus_channel_initiate_contact);
2597
2598         msginfo = kzalloc(msgsize, GFP_KERNEL);
2599
2600         if (msginfo == NULL)
2601                 return -ENOMEM;
2602
2603         ret = vmbus_negotiate_version(msginfo, vmbus_proto_version);
2604
2605         kfree(msginfo);
2606
2607         if (ret != 0)
2608                 return ret;
2609
2610         WARN_ON(atomic_read(&vmbus_connection.nr_chan_fixup_on_resume) == 0);
2611
2612         vmbus_request_offers();
2613
2614         if (wait_for_completion_timeout(
2615                 &vmbus_connection.ready_for_resume_event, 10 * HZ) == 0)
2616                 pr_err("Some vmbus device is missing after suspending?\n");
2617
2618         /* Reset the event for the next suspend. */
2619         reinit_completion(&vmbus_connection.ready_for_suspend_event);
2620
2621         return 0;
2622 }
2623 #else
2624 #define vmbus_bus_suspend NULL
2625 #define vmbus_bus_resume NULL
2626 #endif /* CONFIG_PM_SLEEP */
2627
2628 static const struct acpi_device_id vmbus_acpi_device_ids[] = {
2629         {"VMBUS", 0},
2630         {"VMBus", 0},
2631         {"", 0},
2632 };
2633 MODULE_DEVICE_TABLE(acpi, vmbus_acpi_device_ids);
2634
2635 /*
2636  * Note: we must use the "no_irq" ops, otherwise hibernation can not work with
2637  * PCI device assignment, because "pci_dev_pm_ops" uses the "noirq" ops: in
2638  * the resume path, the pci "noirq" restore op runs before "non-noirq" op (see
2639  * resume_target_kernel() -> dpm_resume_start(), and hibernation_restore() ->
2640  * dpm_resume_end()). This means vmbus_bus_resume() and the pci-hyperv's
2641  * resume callback must also run via the "noirq" ops.
2642  *
2643  * Set suspend_noirq/resume_noirq to NULL for Suspend-to-Idle: see the comment
2644  * earlier in this file before vmbus_pm.
2645  */
2646
2647 static const struct dev_pm_ops vmbus_bus_pm = {
2648         .suspend_noirq  = NULL,
2649         .resume_noirq   = NULL,
2650         .freeze_noirq   = vmbus_bus_suspend,
2651         .thaw_noirq     = vmbus_bus_resume,
2652         .poweroff_noirq = vmbus_bus_suspend,
2653         .restore_noirq  = vmbus_bus_resume
2654 };
2655
2656 static struct acpi_driver vmbus_acpi_driver = {
2657         .name = "vmbus",
2658         .ids = vmbus_acpi_device_ids,
2659         .ops = {
2660                 .add = vmbus_acpi_add,
2661                 .remove = vmbus_acpi_remove,
2662         },
2663         .drv.pm = &vmbus_bus_pm,
2664 };
2665
2666 static void hv_kexec_handler(void)
2667 {
2668         hv_stimer_global_cleanup();
2669         vmbus_initiate_unload(false);
2670         /* Make sure conn_state is set as hv_synic_cleanup checks for it */
2671         mb();
2672         cpuhp_remove_state(hyperv_cpuhp_online);
2673 };
2674
2675 static void hv_crash_handler(struct pt_regs *regs)
2676 {
2677         int cpu;
2678
2679         vmbus_initiate_unload(true);
2680         /*
2681          * In crash handler we can't schedule synic cleanup for all CPUs,
2682          * doing the cleanup for current CPU only. This should be sufficient
2683          * for kdump.
2684          */
2685         cpu = smp_processor_id();
2686         hv_stimer_cleanup(cpu);
2687         hv_synic_disable_regs(cpu);
2688 };
2689
2690 static int hv_synic_suspend(void)
2691 {
2692         /*
2693          * When we reach here, all the non-boot CPUs have been offlined.
2694          * If we're in a legacy configuration where stimer Direct Mode is
2695          * not enabled, the stimers on the non-boot CPUs have been unbound
2696          * in hv_synic_cleanup() -> hv_stimer_legacy_cleanup() ->
2697          * hv_stimer_cleanup() -> clockevents_unbind_device().
2698          *
2699          * hv_synic_suspend() only runs on CPU0 with interrupts disabled.
2700          * Here we do not call hv_stimer_legacy_cleanup() on CPU0 because:
2701          * 1) it's unnecessary as interrupts remain disabled between
2702          * syscore_suspend() and syscore_resume(): see create_image() and
2703          * resume_target_kernel()
2704          * 2) the stimer on CPU0 is automatically disabled later by
2705          * syscore_suspend() -> timekeeping_suspend() -> tick_suspend() -> ...
2706          * -> clockevents_shutdown() -> ... -> hv_ce_shutdown()
2707          * 3) a warning would be triggered if we call
2708          * clockevents_unbind_device(), which may sleep, in an
2709          * interrupts-disabled context.
2710          */
2711
2712         hv_synic_disable_regs(0);
2713
2714         return 0;
2715 }
2716
2717 static void hv_synic_resume(void)
2718 {
2719         hv_synic_enable_regs(0);
2720
2721         /*
2722          * Note: we don't need to call hv_stimer_init(0), because the timer
2723          * on CPU0 is not unbound in hv_synic_suspend(), and the timer is
2724          * automatically re-enabled in timekeeping_resume().
2725          */
2726 }
2727
2728 /* The callbacks run only on CPU0, with irqs_disabled. */
2729 static struct syscore_ops hv_synic_syscore_ops = {
2730         .suspend = hv_synic_suspend,
2731         .resume = hv_synic_resume,
2732 };
2733
2734 static int __init hv_acpi_init(void)
2735 {
2736         int ret, t;
2737
2738         if (!hv_is_hyperv_initialized())
2739                 return -ENODEV;
2740
2741         if (hv_root_partition)
2742                 return 0;
2743
2744         init_completion(&probe_event);
2745
2746         /*
2747          * Get ACPI resources first.
2748          */
2749         ret = acpi_bus_register_driver(&vmbus_acpi_driver);
2750
2751         if (ret)
2752                 return ret;
2753
2754         t = wait_for_completion_timeout(&probe_event, 5*HZ);
2755         if (t == 0) {
2756                 ret = -ETIMEDOUT;
2757                 goto cleanup;
2758         }
2759
2760         /*
2761          * If we're on an architecture with a hardcoded hypervisor
2762          * vector (i.e. x86/x64), override the VMbus interrupt found
2763          * in the ACPI tables. Ensure vmbus_irq is not set since the
2764          * normal Linux IRQ mechanism is not used in this case.
2765          */
2766 #ifdef HYPERVISOR_CALLBACK_VECTOR
2767         vmbus_interrupt = HYPERVISOR_CALLBACK_VECTOR;
2768         vmbus_irq = -1;
2769 #endif
2770
2771         hv_debug_init();
2772
2773         ret = vmbus_bus_init();
2774         if (ret)
2775                 goto cleanup;
2776
2777         hv_setup_kexec_handler(hv_kexec_handler);
2778         hv_setup_crash_handler(hv_crash_handler);
2779
2780         register_syscore_ops(&hv_synic_syscore_ops);
2781
2782         return 0;
2783
2784 cleanup:
2785         acpi_bus_unregister_driver(&vmbus_acpi_driver);
2786         hv_acpi_dev = NULL;
2787         return ret;
2788 }
2789
2790 static void __exit vmbus_exit(void)
2791 {
2792         int cpu;
2793
2794         unregister_syscore_ops(&hv_synic_syscore_ops);
2795
2796         hv_remove_kexec_handler();
2797         hv_remove_crash_handler();
2798         vmbus_connection.conn_state = DISCONNECTED;
2799         hv_stimer_global_cleanup();
2800         vmbus_disconnect();
2801         if (vmbus_irq == -1) {
2802                 hv_remove_vmbus_handler();
2803         } else {
2804                 free_percpu_irq(vmbus_irq, vmbus_evt);
2805                 free_percpu(vmbus_evt);
2806         }
2807         for_each_online_cpu(cpu) {
2808                 struct hv_per_cpu_context *hv_cpu
2809                         = per_cpu_ptr(hv_context.cpu_context, cpu);
2810
2811                 tasklet_kill(&hv_cpu->msg_dpc);
2812         }
2813         hv_debug_rm_all_dir();
2814
2815         vmbus_free_channels();
2816         kfree(vmbus_connection.channels);
2817
2818         if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
2819                 kmsg_dump_unregister(&hv_kmsg_dumper);
2820                 unregister_die_notifier(&hyperv_die_block);
2821         }
2822
2823         /*
2824          * The panic notifier is always registered, hence we should
2825          * also unconditionally unregister it here as well.
2826          */
2827         atomic_notifier_chain_unregister(&panic_notifier_list,
2828                                          &hyperv_panic_block);
2829
2830         free_page((unsigned long)hv_panic_page);
2831         unregister_sysctl_table(hv_ctl_table_hdr);
2832         hv_ctl_table_hdr = NULL;
2833         bus_unregister(&hv_bus);
2834
2835         cpuhp_remove_state(hyperv_cpuhp_online);
2836         hv_synic_free();
2837         acpi_bus_unregister_driver(&vmbus_acpi_driver);
2838 }
2839
2840
2841 MODULE_LICENSE("GPL");
2842 MODULE_DESCRIPTION("Microsoft Hyper-V VMBus Driver");
2843
2844 subsys_initcall(hv_acpi_init);
2845 module_exit(vmbus_exit);