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/platform_device.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/sysctl.h>
  18 #include <linux/slab.h>
  19 #include <linux/acpi.h>
  20 #include <linux/completion.h>
  21 #include <linux/hyperv.h>
  22 #include <linux/kernel_stat.h>
  23 #include <linux/of_address.h>
  24 #include <linux/clockchips.h>
  25 #include <linux/cpu.h>
  26 #include <linux/sched/isolation.h>
  27 #include <linux/sched/task_stack.h>
  28
  29 #include <linux/delay.h>
  30 #include <linux/panic_notifier.h>
  31 #include <linux/ptrace.h>
  32 #include <linux/screen_info.h>
  33 #include <linux/efi.h>
  34 #include <linux/random.h>
  35 #include <linux/kernel.h>
  36 #include <linux/syscore_ops.h>
  37 #include <linux/dma-map-ops.h>
  38 #include <linux/pci.h>
  39 #include <clocksource/hyperv_timer.h>
  40 #include <asm/mshyperv.h>
  41 #include "hyperv_vmbus.h"
  42
  43 struct vmbus_dynid {
  44         struct list_head node;
  45         struct hv_vmbus_device_id id;
  46 };
  47
  48 static struct device  *hv_dev;
  49
  50 static int hyperv_cpuhp_online;
  51
  52 static long __percpu *vmbus_evt;
  53
  54 /* Values parsed from ACPI DSDT */
  55 int vmbus_irq;
  56 int vmbus_interrupt;
  57
  58 /*
  59  * The panic notifier below is responsible solely for unloading the
  60  * vmbus connection, which is necessary in a panic event.
  61  *
  62  * Notice an intrincate relation of this notifier with Hyper-V
  63  * framebuffer panic notifier exists - we need vmbus connection alive
  64  * there in order to succeed, so we need to order both with each other
  65  * [see hvfb_on_panic()] - this is done using notifiers' priorities.
  66  */
  67 static int hv_panic_vmbus_unload(struct notifier_block *nb, unsigned long val,
  68                               void *args)
  69 {
  70         vmbus_initiate_unload(true);
  71         return NOTIFY_DONE;
  72 }
  73 static struct notifier_block hyperv_panic_vmbus_unload_block = {
  74         .notifier_call  = hv_panic_vmbus_unload,
  75         .priority       = INT_MIN + 1, /* almost the latest one to execute */
  76 };
  77
  78 static const char *fb_mmio_name = "fb_range";
  79 static struct resource *fb_mmio;
  80 static struct resource *hyperv_mmio;
  81 static DEFINE_MUTEX(hyperv_mmio_lock);
  82
  83 static int vmbus_exists(void)
  84 {
  85         if (hv_dev == NULL)
  86                 return -ENODEV;
  87
  88         return 0;
  89 }
  90
  91 static u8 channel_monitor_group(const struct vmbus_channel *channel)
  92 {
  93         return (u8)channel->offermsg.monitorid / 32;
  94 }
  95
  96 static u8 channel_monitor_offset(const struct vmbus_channel *channel)
  97 {
  98         return (u8)channel->offermsg.monitorid % 32;
  99 }
 100
 101 static u32 channel_pending(const struct vmbus_channel *channel,
 102                            const struct hv_monitor_page *monitor_page)
 103 {
 104         u8 monitor_group = channel_monitor_group(channel);
 105
 106         return monitor_page->trigger_group[monitor_group].pending;
 107 }
 108
 109 static u32 channel_latency(const struct vmbus_channel *channel,
 110                            const struct hv_monitor_page *monitor_page)
 111 {
 112         u8 monitor_group = channel_monitor_group(channel);
 113         u8 monitor_offset = channel_monitor_offset(channel);
 114
 115         return monitor_page->latency[monitor_group][monitor_offset];
 116 }
 117
 118 static u32 channel_conn_id(struct vmbus_channel *channel,
 119                            struct hv_monitor_page *monitor_page)
 120 {
 121         u8 monitor_group = channel_monitor_group(channel);
 122         u8 monitor_offset = channel_monitor_offset(channel);
 123
 124         return monitor_page->parameter[monitor_group][monitor_offset].connectionid.u.id;
 125 }
 126
 127 static ssize_t id_show(struct device *dev, struct device_attribute *dev_attr,
 128                        char *buf)
 129 {
 130         struct hv_device *hv_dev = device_to_hv_device(dev);
 131
 132         if (!hv_dev->channel)
 133                 return -ENODEV;
 134         return sprintf(buf, "%d\n", hv_dev->channel->offermsg.child_relid);
 135 }
 136 static DEVICE_ATTR_RO(id);
 137
 138 static ssize_t state_show(struct device *dev, struct device_attribute *dev_attr,
 139                           char *buf)
 140 {
 141         struct hv_device *hv_dev = device_to_hv_device(dev);
 142
 143         if (!hv_dev->channel)
 144                 return -ENODEV;
 145         return sprintf(buf, "%d\n", hv_dev->channel->state);
 146 }
 147 static DEVICE_ATTR_RO(state);
 148
 149 static ssize_t monitor_id_show(struct device *dev,
 150                                struct device_attribute *dev_attr, char *buf)
 151 {
 152         struct hv_device *hv_dev = device_to_hv_device(dev);
 153
 154         if (!hv_dev->channel)
 155                 return -ENODEV;
 156         return sprintf(buf, "%d\n", hv_dev->channel->offermsg.monitorid);
 157 }
 158 static DEVICE_ATTR_RO(monitor_id);
 159
 160 static ssize_t class_id_show(struct device *dev,
 161                                struct device_attribute *dev_attr, char *buf)
 162 {
 163         struct hv_device *hv_dev = device_to_hv_device(dev);
 164
 165         if (!hv_dev->channel)
 166                 return -ENODEV;
 167         return sprintf(buf, "{%pUl}\n",
 168                        &hv_dev->channel->offermsg.offer.if_type);
 169 }
 170 static DEVICE_ATTR_RO(class_id);
 171
 172 static ssize_t device_id_show(struct device *dev,
 173                               struct device_attribute *dev_attr, char *buf)
 174 {
 175         struct hv_device *hv_dev = device_to_hv_device(dev);
 176
 177         if (!hv_dev->channel)
 178                 return -ENODEV;
 179         return sprintf(buf, "{%pUl}\n",
 180                        &hv_dev->channel->offermsg.offer.if_instance);
 181 }
 182 static DEVICE_ATTR_RO(device_id);
 183
 184 static ssize_t modalias_show(struct device *dev,
 185                              struct device_attribute *dev_attr, char *buf)
 186 {
 187         struct hv_device *hv_dev = device_to_hv_device(dev);
 188
 189         return sprintf(buf, "vmbus:%*phN\n", UUID_SIZE, &hv_dev->dev_type);
 190 }
 191 static DEVICE_ATTR_RO(modalias);
 192
 193 #ifdef CONFIG_NUMA
 194 static ssize_t numa_node_show(struct device *dev,
 195                               struct device_attribute *attr, char *buf)
 196 {
 197         struct hv_device *hv_dev = device_to_hv_device(dev);
 198
 199         if (!hv_dev->channel)
 200                 return -ENODEV;
 201
 202         return sprintf(buf, "%d\n", cpu_to_node(hv_dev->channel->target_cpu));
 203 }
 204 static DEVICE_ATTR_RO(numa_node);
 205 #endif
 206
 207 static ssize_t server_monitor_pending_show(struct device *dev,
 208                                            struct device_attribute *dev_attr,
 209                                            char *buf)
 210 {
 211         struct hv_device *hv_dev = device_to_hv_device(dev);
 212
 213         if (!hv_dev->channel)
 214                 return -ENODEV;
 215         return sprintf(buf, "%d\n",
 216                        channel_pending(hv_dev->channel,
 217                                        vmbus_connection.monitor_pages[0]));
 218 }
 219 static DEVICE_ATTR_RO(server_monitor_pending);
 220
 221 static ssize_t client_monitor_pending_show(struct device *dev,
 222                                            struct device_attribute *dev_attr,
 223                                            char *buf)
 224 {
 225         struct hv_device *hv_dev = device_to_hv_device(dev);
 226
 227         if (!hv_dev->channel)
 228                 return -ENODEV;
 229         return sprintf(buf, "%d\n",
 230                        channel_pending(hv_dev->channel,
 231                                        vmbus_connection.monitor_pages[1]));
 232 }
 233 static DEVICE_ATTR_RO(client_monitor_pending);
 234
 235 static ssize_t server_monitor_latency_show(struct device *dev,
 236                                            struct device_attribute *dev_attr,
 237                                            char *buf)
 238 {
 239         struct hv_device *hv_dev = device_to_hv_device(dev);
 240
 241         if (!hv_dev->channel)
 242                 return -ENODEV;
 243         return sprintf(buf, "%d\n",
 244                        channel_latency(hv_dev->channel,
 245                                        vmbus_connection.monitor_pages[0]));
 246 }
 247 static DEVICE_ATTR_RO(server_monitor_latency);
 248
 249 static ssize_t client_monitor_latency_show(struct device *dev,
 250                                            struct device_attribute *dev_attr,
 251                                            char *buf)
 252 {
 253         struct hv_device *hv_dev = device_to_hv_device(dev);
 254
 255         if (!hv_dev->channel)
 256                 return -ENODEV;
 257         return sprintf(buf, "%d\n",
 258                        channel_latency(hv_dev->channel,
 259                                        vmbus_connection.monitor_pages[1]));
 260 }
 261 static DEVICE_ATTR_RO(client_monitor_latency);
 262
 263 static ssize_t server_monitor_conn_id_show(struct device *dev,
 264                                            struct device_attribute *dev_attr,
 265                                            char *buf)
 266 {
 267         struct hv_device *hv_dev = device_to_hv_device(dev);
 268
 269         if (!hv_dev->channel)
 270                 return -ENODEV;
 271         return sprintf(buf, "%d\n",
 272                        channel_conn_id(hv_dev->channel,
 273                                        vmbus_connection.monitor_pages[0]));
 274 }
 275 static DEVICE_ATTR_RO(server_monitor_conn_id);
 276
 277 static ssize_t client_monitor_conn_id_show(struct device *dev,
 278                                            struct device_attribute *dev_attr,
 279                                            char *buf)
 280 {
 281         struct hv_device *hv_dev = device_to_hv_device(dev);
 282
 283         if (!hv_dev->channel)
 284                 return -ENODEV;
 285         return sprintf(buf, "%d\n",
 286                        channel_conn_id(hv_dev->channel,
 287                                        vmbus_connection.monitor_pages[1]));
 288 }
 289 static DEVICE_ATTR_RO(client_monitor_conn_id);
 290
 291 static ssize_t out_intr_mask_show(struct device *dev,
 292                                   struct device_attribute *dev_attr, char *buf)
 293 {
 294         struct hv_device *hv_dev = device_to_hv_device(dev);
 295         struct hv_ring_buffer_debug_info outbound;
 296         int ret;
 297
 298         if (!hv_dev->channel)
 299                 return -ENODEV;
 300
 301         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
 302                                           &outbound);
 303         if (ret < 0)
 304                 return ret;
 305
 306         return sprintf(buf, "%d\n", outbound.current_interrupt_mask);
 307 }
 308 static DEVICE_ATTR_RO(out_intr_mask);
 309
 310 static ssize_t out_read_index_show(struct device *dev,
 311                                    struct device_attribute *dev_attr, char *buf)
 312 {
 313         struct hv_device *hv_dev = device_to_hv_device(dev);
 314         struct hv_ring_buffer_debug_info outbound;
 315         int ret;
 316
 317         if (!hv_dev->channel)
 318                 return -ENODEV;
 319
 320         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
 321                                           &outbound);
 322         if (ret < 0)
 323                 return ret;
 324         return sprintf(buf, "%d\n", outbound.current_read_index);
 325 }
 326 static DEVICE_ATTR_RO(out_read_index);
 327
 328 static ssize_t out_write_index_show(struct device *dev,
 329                                     struct device_attribute *dev_attr,
 330                                     char *buf)
 331 {
 332         struct hv_device *hv_dev = device_to_hv_device(dev);
 333         struct hv_ring_buffer_debug_info outbound;
 334         int ret;
 335
 336         if (!hv_dev->channel)
 337                 return -ENODEV;
 338
 339         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
 340                                           &outbound);
 341         if (ret < 0)
 342                 return ret;
 343         return sprintf(buf, "%d\n", outbound.current_write_index);
 344 }
 345 static DEVICE_ATTR_RO(out_write_index);
 346
 347 static ssize_t out_read_bytes_avail_show(struct device *dev,
 348                                          struct device_attribute *dev_attr,
 349                                          char *buf)
 350 {
 351         struct hv_device *hv_dev = device_to_hv_device(dev);
 352         struct hv_ring_buffer_debug_info outbound;
 353         int ret;
 354
 355         if (!hv_dev->channel)
 356                 return -ENODEV;
 357
 358         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
 359                                           &outbound);
 360         if (ret < 0)
 361                 return ret;
 362         return sprintf(buf, "%d\n", outbound.bytes_avail_toread);
 363 }
 364 static DEVICE_ATTR_RO(out_read_bytes_avail);
 365
 366 static ssize_t out_write_bytes_avail_show(struct device *dev,
 367                                           struct device_attribute *dev_attr,
 368                                           char *buf)
 369 {
 370         struct hv_device *hv_dev = device_to_hv_device(dev);
 371         struct hv_ring_buffer_debug_info outbound;
 372         int ret;
 373
 374         if (!hv_dev->channel)
 375                 return -ENODEV;
 376
 377         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
 378                                           &outbound);
 379         if (ret < 0)
 380                 return ret;
 381         return sprintf(buf, "%d\n", outbound.bytes_avail_towrite);
 382 }
 383 static DEVICE_ATTR_RO(out_write_bytes_avail);
 384
 385 static ssize_t in_intr_mask_show(struct device *dev,
 386                                  struct device_attribute *dev_attr, char *buf)
 387 {
 388         struct hv_device *hv_dev = device_to_hv_device(dev);
 389         struct hv_ring_buffer_debug_info inbound;
 390         int ret;
 391
 392         if (!hv_dev->channel)
 393                 return -ENODEV;
 394
 395         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 396         if (ret < 0)
 397                 return ret;
 398
 399         return sprintf(buf, "%d\n", inbound.current_interrupt_mask);
 400 }
 401 static DEVICE_ATTR_RO(in_intr_mask);
 402
 403 static ssize_t in_read_index_show(struct device *dev,
 404                                   struct device_attribute *dev_attr, char *buf)
 405 {
 406         struct hv_device *hv_dev = device_to_hv_device(dev);
 407         struct hv_ring_buffer_debug_info inbound;
 408         int ret;
 409
 410         if (!hv_dev->channel)
 411                 return -ENODEV;
 412
 413         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 414         if (ret < 0)
 415                 return ret;
 416
 417         return sprintf(buf, "%d\n", inbound.current_read_index);
 418 }
 419 static DEVICE_ATTR_RO(in_read_index);
 420
 421 static ssize_t in_write_index_show(struct device *dev,
 422                                    struct device_attribute *dev_attr, char *buf)
 423 {
 424         struct hv_device *hv_dev = device_to_hv_device(dev);
 425         struct hv_ring_buffer_debug_info inbound;
 426         int ret;
 427
 428         if (!hv_dev->channel)
 429                 return -ENODEV;
 430
 431         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 432         if (ret < 0)
 433                 return ret;
 434
 435         return sprintf(buf, "%d\n", inbound.current_write_index);
 436 }
 437 static DEVICE_ATTR_RO(in_write_index);
 438
 439 static ssize_t in_read_bytes_avail_show(struct device *dev,
 440                                         struct device_attribute *dev_attr,
 441                                         char *buf)
 442 {
 443         struct hv_device *hv_dev = device_to_hv_device(dev);
 444         struct hv_ring_buffer_debug_info inbound;
 445         int ret;
 446
 447         if (!hv_dev->channel)
 448                 return -ENODEV;
 449
 450         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 451         if (ret < 0)
 452                 return ret;
 453
 454         return sprintf(buf, "%d\n", inbound.bytes_avail_toread);
 455 }
 456 static DEVICE_ATTR_RO(in_read_bytes_avail);
 457
 458 static ssize_t in_write_bytes_avail_show(struct device *dev,
 459                                          struct device_attribute *dev_attr,
 460                                          char *buf)
 461 {
 462         struct hv_device *hv_dev = device_to_hv_device(dev);
 463         struct hv_ring_buffer_debug_info inbound;
 464         int ret;
 465
 466         if (!hv_dev->channel)
 467                 return -ENODEV;
 468
 469         ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 470         if (ret < 0)
 471                 return ret;
 472
 473         return sprintf(buf, "%d\n", inbound.bytes_avail_towrite);
 474 }
 475 static DEVICE_ATTR_RO(in_write_bytes_avail);
 476
 477 static ssize_t channel_vp_mapping_show(struct device *dev,
 478                                        struct device_attribute *dev_attr,
 479                                        char *buf)
 480 {
 481         struct hv_device *hv_dev = device_to_hv_device(dev);
 482         struct vmbus_channel *channel = hv_dev->channel, *cur_sc;
 483         int buf_size = PAGE_SIZE, n_written, tot_written;
 484         struct list_head *cur;
 485
 486         if (!channel)
 487                 return -ENODEV;
 488
 489         mutex_lock(&vmbus_connection.channel_mutex);
 490
 491         tot_written = snprintf(buf, buf_size, "%u:%u\n",
 492                 channel->offermsg.child_relid, channel->target_cpu);
 493
 494         list_for_each(cur, &channel->sc_list) {
 495                 if (tot_written >= buf_size - 1)
 496                         break;
 497
 498                 cur_sc = list_entry(cur, struct vmbus_channel, sc_list);
 499                 n_written = scnprintf(buf + tot_written,
 500                                      buf_size - tot_written,
 501                                      "%u:%u\n",
 502                                      cur_sc->offermsg.child_relid,
 503                                      cur_sc->target_cpu);
 504                 tot_written += n_written;
 505         }
 506
 507         mutex_unlock(&vmbus_connection.channel_mutex);
 508
 509         return tot_written;
 510 }
 511 static DEVICE_ATTR_RO(channel_vp_mapping);
 512
 513 static ssize_t vendor_show(struct device *dev,
 514                            struct device_attribute *dev_attr,
 515                            char *buf)
 516 {
 517         struct hv_device *hv_dev = device_to_hv_device(dev);
 518
 519         return sprintf(buf, "0x%x\n", hv_dev->vendor_id);
 520 }
 521 static DEVICE_ATTR_RO(vendor);
 522
 523 static ssize_t device_show(struct device *dev,
 524                            struct device_attribute *dev_attr,
 525                            char *buf)
 526 {
 527         struct hv_device *hv_dev = device_to_hv_device(dev);
 528
 529         return sprintf(buf, "0x%x\n", hv_dev->device_id);
 530 }
 531 static DEVICE_ATTR_RO(device);
 532
 533 static ssize_t driver_override_store(struct device *dev,
 534                                      struct device_attribute *attr,
 535                                      const char *buf, size_t count)
 536 {
 537         struct hv_device *hv_dev = device_to_hv_device(dev);
 538         int ret;
 539
 540         ret = driver_set_override(dev, &hv_dev->driver_override, buf, count);
 541         if (ret)
 542                 return ret;
 543
 544         return count;
 545 }
 546
 547 static ssize_t driver_override_show(struct device *dev,
 548                                     struct device_attribute *attr, char *buf)
 549 {
 550         struct hv_device *hv_dev = device_to_hv_device(dev);
 551         ssize_t len;
 552
 553         device_lock(dev);
 554         len = snprintf(buf, PAGE_SIZE, "%s\n", hv_dev->driver_override);
 555         device_unlock(dev);
 556
 557         return len;
 558 }
 559 static DEVICE_ATTR_RW(driver_override);
 560
 561 /* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
 562 static struct attribute *vmbus_dev_attrs[] = {
 563         &dev_attr_id.attr,
 564         &dev_attr_state.attr,
 565         &dev_attr_monitor_id.attr,
 566         &dev_attr_class_id.attr,
 567         &dev_attr_device_id.attr,
 568         &dev_attr_modalias.attr,
 569 #ifdef CONFIG_NUMA
 570         &dev_attr_numa_node.attr,
 571 #endif
 572         &dev_attr_server_monitor_pending.attr,
 573         &dev_attr_client_monitor_pending.attr,
 574         &dev_attr_server_monitor_latency.attr,
 575         &dev_attr_client_monitor_latency.attr,
 576         &dev_attr_server_monitor_conn_id.attr,
 577         &dev_attr_client_monitor_conn_id.attr,
 578         &dev_attr_out_intr_mask.attr,
 579         &dev_attr_out_read_index.attr,
 580         &dev_attr_out_write_index.attr,
 581         &dev_attr_out_read_bytes_avail.attr,
 582         &dev_attr_out_write_bytes_avail.attr,
 583         &dev_attr_in_intr_mask.attr,
 584         &dev_attr_in_read_index.attr,
 585         &dev_attr_in_write_index.attr,
 586         &dev_attr_in_read_bytes_avail.attr,
 587         &dev_attr_in_write_bytes_avail.attr,
 588         &dev_attr_channel_vp_mapping.attr,
 589         &dev_attr_vendor.attr,
 590         &dev_attr_device.attr,
 591         &dev_attr_driver_override.attr,
 592         NULL,
 593 };
 594
 595 /*
 596  * Device-level attribute_group callback function. Returns the permission for
 597  * each attribute, and returns 0 if an attribute is not visible.
 598  */
 599 static umode_t vmbus_dev_attr_is_visible(struct kobject *kobj,
 600                                          struct attribute *attr, int idx)
 601 {
 602         struct device *dev = kobj_to_dev(kobj);
 603         const struct hv_device *hv_dev = device_to_hv_device(dev);
 604
 605         /* Hide the monitor attributes if the monitor mechanism is not used. */
 606         if (!hv_dev->channel->offermsg.monitor_allocated &&
 607             (attr == &dev_attr_monitor_id.attr ||
 608              attr == &dev_attr_server_monitor_pending.attr ||
 609              attr == &dev_attr_client_monitor_pending.attr ||
 610              attr == &dev_attr_server_monitor_latency.attr ||
 611              attr == &dev_attr_client_monitor_latency.attr ||
 612              attr == &dev_attr_server_monitor_conn_id.attr ||
 613              attr == &dev_attr_client_monitor_conn_id.attr))
 614                 return 0;
 615
 616         return attr->mode;
 617 }
 618
 619 static const struct attribute_group vmbus_dev_group = {
 620         .attrs = vmbus_dev_attrs,
 621         .is_visible = vmbus_dev_attr_is_visible
 622 };
 623 __ATTRIBUTE_GROUPS(vmbus_dev);
 624
 625 /* Set up the attribute for /sys/bus/vmbus/hibernation */
 626 static ssize_t hibernation_show(const struct bus_type *bus, char *buf)
 627 {
 628         return sprintf(buf, "%d\n", !!hv_is_hibernation_supported());
 629 }
 630
 631 static BUS_ATTR_RO(hibernation);
 632
 633 static struct attribute *vmbus_bus_attrs[] = {
 634         &bus_attr_hibernation.attr,
 635         NULL,
 636 };
 637 static const struct attribute_group vmbus_bus_group = {
 638         .attrs = vmbus_bus_attrs,
 639 };
 640 __ATTRIBUTE_GROUPS(vmbus_bus);
 641
 642 /*
 643  * vmbus_uevent - add uevent for our device
 644  *
 645  * This routine is invoked when a device is added or removed on the vmbus to
 646  * generate a uevent to udev in the userspace. The udev will then look at its
 647  * rule and the uevent generated here to load the appropriate driver
 648  *
 649  * The alias string will be of the form vmbus:guid where guid is the string
 650  * representation of the device guid (each byte of the guid will be
 651  * represented with two hex characters.
 652  */
 653 static int vmbus_uevent(const struct device *device, struct kobj_uevent_env *env)
 654 {
 655         const struct hv_device *dev = device_to_hv_device(device);
 656         const char *format = "MODALIAS=vmbus:%*phN";
 657
 658         return add_uevent_var(env, format, UUID_SIZE, &dev->dev_type);
 659 }
 660
 661 static const struct hv_vmbus_device_id *
 662 hv_vmbus_dev_match(const struct hv_vmbus_device_id *id, const guid_t *guid)
 663 {
 664         if (id == NULL)
 665                 return NULL; /* empty device table */
 666
 667         for (; !guid_is_null(&id->guid); id++)
 668                 if (guid_equal(&id->guid, guid))
 669                         return id;
 670
 671         return NULL;
 672 }
 673
 674 static const struct hv_vmbus_device_id *
 675 hv_vmbus_dynid_match(struct hv_driver *drv, const guid_t *guid)
 676 {
 677         const struct hv_vmbus_device_id *id = NULL;
 678         struct vmbus_dynid *dynid;
 679
 680         spin_lock(&drv->dynids.lock);
 681         list_for_each_entry(dynid, &drv->dynids.list, node) {
 682                 if (guid_equal(&dynid->id.guid, guid)) {
 683                         id = &dynid->id;
 684                         break;
 685                 }
 686         }
 687         spin_unlock(&drv->dynids.lock);
 688
 689         return id;
 690 }
 691
 692 static const struct hv_vmbus_device_id vmbus_device_null;
 693
 694 /*
 695  * Return a matching hv_vmbus_device_id pointer.
 696  * If there is no match, return NULL.
 697  */
 698 static const struct hv_vmbus_device_id *hv_vmbus_get_id(struct hv_driver *drv,
 699                                                         struct hv_device *dev)
 700 {
 701         const guid_t *guid = &dev->dev_type;
 702         const struct hv_vmbus_device_id *id;
 703
 704         /* When driver_override is set, only bind to the matching driver */
 705         if (dev->driver_override && strcmp(dev->driver_override, drv->name))
 706                 return NULL;
 707
 708         /* Look at the dynamic ids first, before the static ones */
 709         id = hv_vmbus_dynid_match(drv, guid);
 710         if (!id)
 711                 id = hv_vmbus_dev_match(drv->id_table, guid);
 712
 713         /* driver_override will always match, send a dummy id */
 714         if (!id && dev->driver_override)
 715                 id = &vmbus_device_null;
 716
 717         return id;
 718 }
 719
 720 /* vmbus_add_dynid - add a new device ID to this driver and re-probe devices */
 721 static int vmbus_add_dynid(struct hv_driver *drv, guid_t *guid)
 722 {
 723         struct vmbus_dynid *dynid;
 724
 725         dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
 726         if (!dynid)
 727                 return -ENOMEM;
 728
 729         dynid->id.guid = *guid;
 730
 731         spin_lock(&drv->dynids.lock);
 732         list_add_tail(&dynid->node, &drv->dynids.list);
 733         spin_unlock(&drv->dynids.lock);
 734
 735         return driver_attach(&drv->driver);
 736 }
 737
 738 static void vmbus_free_dynids(struct hv_driver *drv)
 739 {
 740         struct vmbus_dynid *dynid, *n;
 741
 742         spin_lock(&drv->dynids.lock);
 743         list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
 744                 list_del(&dynid->node);
 745                 kfree(dynid);
 746         }
 747         spin_unlock(&drv->dynids.lock);
 748 }
 749
 750 /*
 751  * store_new_id - sysfs frontend to vmbus_add_dynid()
 752  *
 753  * Allow GUIDs to be added to an existing driver via sysfs.
 754  */
 755 static ssize_t new_id_store(struct device_driver *driver, const char *buf,
 756                             size_t count)
 757 {
 758         struct hv_driver *drv = drv_to_hv_drv(driver);
 759         guid_t guid;
 760         ssize_t retval;
 761
 762         retval = guid_parse(buf, &guid);
 763         if (retval)
 764                 return retval;
 765
 766         if (hv_vmbus_dynid_match(drv, &guid))
 767                 return -EEXIST;
 768
 769         retval = vmbus_add_dynid(drv, &guid);
 770         if (retval)
 771                 return retval;
 772         return count;
 773 }
 774 static DRIVER_ATTR_WO(new_id);
 775
 776 /*
 777  * store_remove_id - remove a PCI device ID from this driver
 778  *
 779  * Removes a dynamic pci device ID to this driver.
 780  */
 781 static ssize_t remove_id_store(struct device_driver *driver, const char *buf,
 782                                size_t count)
 783 {
 784         struct hv_driver *drv = drv_to_hv_drv(driver);
 785         struct vmbus_dynid *dynid, *n;
 786         guid_t guid;
 787         ssize_t retval;
 788
 789         retval = guid_parse(buf, &guid);
 790         if (retval)
 791                 return retval;
 792
 793         retval = -ENODEV;
 794         spin_lock(&drv->dynids.lock);
 795         list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
 796                 struct hv_vmbus_device_id *id = &dynid->id;
 797
 798                 if (guid_equal(&id->guid, &guid)) {
 799                         list_del(&dynid->node);
 800                         kfree(dynid);
 801                         retval = count;
 802                         break;
 803                 }
 804         }
 805         spin_unlock(&drv->dynids.lock);
 806
 807         return retval;
 808 }
 809 static DRIVER_ATTR_WO(remove_id);
 810
 811 static struct attribute *vmbus_drv_attrs[] = {
 812         &driver_attr_new_id.attr,
 813         &driver_attr_remove_id.attr,
 814         NULL,
 815 };
 816 ATTRIBUTE_GROUPS(vmbus_drv);
 817
 818
 819 /*
 820  * vmbus_match - Attempt to match the specified device to the specified driver
 821  */
 822 static int vmbus_match(struct device *device, struct device_driver *driver)
 823 {
 824         struct hv_driver *drv = drv_to_hv_drv(driver);
 825         struct hv_device *hv_dev = device_to_hv_device(device);
 826
 827         /* The hv_sock driver handles all hv_sock offers. */
 828         if (is_hvsock_channel(hv_dev->channel))
 829                 return drv->hvsock;
 830
 831         if (hv_vmbus_get_id(drv, hv_dev))
 832                 return 1;
 833
 834         return 0;
 835 }
 836
 837 /*
 838  * vmbus_probe - Add the new vmbus's child device
 839  */
 840 static int vmbus_probe(struct device *child_device)
 841 {
 842         int ret = 0;
 843         struct hv_driver *drv =
 844                         drv_to_hv_drv(child_device->driver);
 845         struct hv_device *dev = device_to_hv_device(child_device);
 846         const struct hv_vmbus_device_id *dev_id;
 847
 848         dev_id = hv_vmbus_get_id(drv, dev);
 849         if (drv->probe) {
 850                 ret = drv->probe(dev, dev_id);
 851                 if (ret != 0)
 852                         pr_err("probe failed for device %s (%d)\n",
 853                                dev_name(child_device), ret);
 854
 855         } else {
 856                 pr_err("probe not set for driver %s\n",
 857                        dev_name(child_device));
 858                 ret = -ENODEV;
 859         }
 860         return ret;
 861 }
 862
 863 /*
 864  * vmbus_dma_configure -- Configure DMA coherence for VMbus device
 865  */
 866 static int vmbus_dma_configure(struct device *child_device)
 867 {
 868         /*
 869          * On ARM64, propagate the DMA coherence setting from the top level
 870          * VMbus ACPI device to the child VMbus device being added here.
 871          * On x86/x64 coherence is assumed and these calls have no effect.
 872          */
 873         hv_setup_dma_ops(child_device,
 874                 device_get_dma_attr(hv_dev) == DEV_DMA_COHERENT);
 875         return 0;
 876 }
 877
 878 /*
 879  * vmbus_remove - Remove a vmbus device
 880  */
 881 static void vmbus_remove(struct device *child_device)
 882 {
 883         struct hv_driver *drv;
 884         struct hv_device *dev = device_to_hv_device(child_device);
 885
 886         if (child_device->driver) {
 887                 drv = drv_to_hv_drv(child_device->driver);
 888                 if (drv->remove)
 889                         drv->remove(dev);
 890         }
 891 }
 892
 893 /*
 894  * vmbus_shutdown - Shutdown a vmbus device
 895  */
 896 static void vmbus_shutdown(struct device *child_device)
 897 {
 898         struct hv_driver *drv;
 899         struct hv_device *dev = device_to_hv_device(child_device);
 900
 901
 902         /* The device may not be attached yet */
 903         if (!child_device->driver)
 904                 return;
 905
 906         drv = drv_to_hv_drv(child_device->driver);
 907
 908         if (drv->shutdown)
 909                 drv->shutdown(dev);
 910 }
 911
 912 #ifdef CONFIG_PM_SLEEP
 913 /*
 914  * vmbus_suspend - Suspend a vmbus device
 915  */
 916 static int vmbus_suspend(struct device *child_device)
 917 {
 918         struct hv_driver *drv;
 919         struct hv_device *dev = device_to_hv_device(child_device);
 920
 921         /* The device may not be attached yet */
 922         if (!child_device->driver)
 923                 return 0;
 924
 925         drv = drv_to_hv_drv(child_device->driver);
 926         if (!drv->suspend)
 927                 return -EOPNOTSUPP;
 928
 929         return drv->suspend(dev);
 930 }
 931
 932 /*
 933  * vmbus_resume - Resume a vmbus device
 934  */
 935 static int vmbus_resume(struct device *child_device)
 936 {
 937         struct hv_driver *drv;
 938         struct hv_device *dev = device_to_hv_device(child_device);
 939
 940         /* The device may not be attached yet */
 941         if (!child_device->driver)
 942                 return 0;
 943
 944         drv = drv_to_hv_drv(child_device->driver);
 945         if (!drv->resume)
 946                 return -EOPNOTSUPP;
 947
 948         return drv->resume(dev);
 949 }
 950 #else
 951 #define vmbus_suspend NULL
 952 #define vmbus_resume NULL
 953 #endif /* CONFIG_PM_SLEEP */
 954
 955 /*
 956  * vmbus_device_release - Final callback release of the vmbus child device
 957  */
 958 static void vmbus_device_release(struct device *device)
 959 {
 960         struct hv_device *hv_dev = device_to_hv_device(device);
 961         struct vmbus_channel *channel = hv_dev->channel;
 962
 963         hv_debug_rm_dev_dir(hv_dev);
 964
 965         mutex_lock(&vmbus_connection.channel_mutex);
 966         hv_process_channel_removal(channel);
 967         mutex_unlock(&vmbus_connection.channel_mutex);
 968         kfree(hv_dev);
 969 }
 970
 971 /*
 972  * Note: we must use the "noirq" ops: see the comment before vmbus_bus_pm.
 973  *
 974  * suspend_noirq/resume_noirq are set to NULL to support Suspend-to-Idle: we
 975  * shouldn't suspend the vmbus devices upon Suspend-to-Idle, otherwise there
 976  * is no way to wake up a Generation-2 VM.
 977  *
 978  * The other 4 ops are for hibernation.
 979  */
 980
 981 static const struct dev_pm_ops vmbus_pm = {
 982         .suspend_noirq  = NULL,
 983         .resume_noirq   = NULL,
 984         .freeze_noirq   = vmbus_suspend,
 985         .thaw_noirq     = vmbus_resume,
 986         .poweroff_noirq = vmbus_suspend,
 987         .restore_noirq  = vmbus_resume,
 988 };
 989
 990 /* The one and only one */
 991 static const struct bus_type  hv_bus = {
 992         .name =         "vmbus",
 993         .match =                vmbus_match,
 994         .shutdown =             vmbus_shutdown,
 995         .remove =               vmbus_remove,
 996         .probe =                vmbus_probe,
 997         .uevent =               vmbus_uevent,
 998         .dma_configure =        vmbus_dma_configure,
 999         .dev_groups =           vmbus_dev_groups,
1000         .drv_groups =           vmbus_drv_groups,
1001         .bus_groups =           vmbus_bus_groups,
1002         .pm =                   &vmbus_pm,
1003 };
1004
1005 struct onmessage_work_context {
1006         struct work_struct work;
1007         struct {
1008                 struct hv_message_header header;
1009                 u8 payload[];
1010         } msg;
1011 };
1012
1013 static void vmbus_onmessage_work(struct work_struct *work)
1014 {
1015         struct onmessage_work_context *ctx;
1016
1017         /* Do not process messages if we're in DISCONNECTED state */
1018         if (vmbus_connection.conn_state == DISCONNECTED)
1019                 return;
1020
1021         ctx = container_of(work, struct onmessage_work_context,
1022                            work);
1023         vmbus_onmessage((struct vmbus_channel_message_header *)
1024                         &ctx->msg.payload);
1025         kfree(ctx);
1026 }
1027
1028 void vmbus_on_msg_dpc(unsigned long data)
1029 {
1030         struct hv_per_cpu_context *hv_cpu = (void *)data;
1031         void *page_addr = hv_cpu->synic_message_page;
1032         struct hv_message msg_copy, *msg = (struct hv_message *)page_addr +
1033                                   VMBUS_MESSAGE_SINT;
1034         struct vmbus_channel_message_header *hdr;
1035         enum vmbus_channel_message_type msgtype;
1036         const struct vmbus_channel_message_table_entry *entry;
1037         struct onmessage_work_context *ctx;
1038         __u8 payload_size;
1039         u32 message_type;
1040
1041         /*
1042          * 'enum vmbus_channel_message_type' is supposed to always be 'u32' as
1043          * it is being used in 'struct vmbus_channel_message_header' definition
1044          * which is supposed to match hypervisor ABI.
1045          */
1046         BUILD_BUG_ON(sizeof(enum vmbus_channel_message_type) != sizeof(u32));
1047
1048         /*
1049          * Since the message is in memory shared with the host, an erroneous or
1050          * malicious Hyper-V could modify the message while vmbus_on_msg_dpc()
1051          * or individual message handlers are executing; to prevent this, copy
1052          * the message into private memory.
1053          */
1054         memcpy(&msg_copy, msg, sizeof(struct hv_message));
1055
1056         message_type = msg_copy.header.message_type;
1057         if (message_type == HVMSG_NONE)
1058                 /* no msg */
1059                 return;
1060
1061         hdr = (struct vmbus_channel_message_header *)msg_copy.u.payload;
1062         msgtype = hdr->msgtype;
1063
1064         trace_vmbus_on_msg_dpc(hdr);
1065
1066         if (msgtype >= CHANNELMSG_COUNT) {
1067                 WARN_ONCE(1, "unknown msgtype=%d\n", msgtype);
1068                 goto msg_handled;
1069         }
1070
1071         payload_size = msg_copy.header.payload_size;
1072         if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT) {
1073                 WARN_ONCE(1, "payload size is too large (%d)\n", payload_size);
1074                 goto msg_handled;
1075         }
1076
1077         entry = &channel_message_table[msgtype];
1078
1079         if (!entry->message_handler)
1080                 goto msg_handled;
1081
1082         if (payload_size < entry->min_payload_len) {
1083                 WARN_ONCE(1, "message too short: msgtype=%d len=%d\n", msgtype, payload_size);
1084                 goto msg_handled;
1085         }
1086
1087         if (entry->handler_type == VMHT_BLOCKING) {
1088                 ctx = kmalloc(struct_size(ctx, msg.payload, payload_size), GFP_ATOMIC);
1089                 if (ctx == NULL)
1090                         return;
1091
1092                 INIT_WORK(&ctx->work, vmbus_onmessage_work);
1093                 ctx->msg.header = msg_copy.header;
1094                 memcpy(&ctx->msg.payload, msg_copy.u.payload, payload_size);
1095
1096                 /*
1097                  * The host can generate a rescind message while we
1098                  * may still be handling the original offer. We deal with
1099                  * this condition by relying on the synchronization provided
1100                  * by offer_in_progress and by channel_mutex.  See also the
1101                  * inline comments in vmbus_onoffer_rescind().
1102                  */
1103                 switch (msgtype) {
1104                 case CHANNELMSG_RESCIND_CHANNELOFFER:
1105                         /*
1106                          * If we are handling the rescind message;
1107                          * schedule the work on the global work queue.
1108                          *
1109                          * The OFFER message and the RESCIND message should
1110                          * not be handled by the same serialized work queue,
1111                          * because the OFFER handler may call vmbus_open(),
1112                          * which tries to open the channel by sending an
1113                          * OPEN_CHANNEL message to the host and waits for
1114                          * the host's response; however, if the host has
1115                          * rescinded the channel before it receives the
1116                          * OPEN_CHANNEL message, the host just silently
1117                          * ignores the OPEN_CHANNEL message; as a result,
1118                          * the guest's OFFER handler hangs for ever, if we
1119                          * handle the RESCIND message in the same serialized
1120                          * work queue: the RESCIND handler can not start to
1121                          * run before the OFFER handler finishes.
1122                          */
1123                         if (vmbus_connection.ignore_any_offer_msg)
1124                                 break;
1125                         queue_work(vmbus_connection.rescind_work_queue, &ctx->work);
1126                         break;
1127
1128                 case CHANNELMSG_OFFERCHANNEL:
1129                         /*
1130                          * The host sends the offer message of a given channel
1131                          * before sending the rescind message of the same
1132                          * channel.  These messages are sent to the guest's
1133                          * connect CPU; the guest then starts processing them
1134                          * in the tasklet handler on this CPU:
1135                          *
1136                          * VMBUS_CONNECT_CPU
1137                          *
1138                          * [vmbus_on_msg_dpc()]
1139                          * atomic_inc()  // CHANNELMSG_OFFERCHANNEL
1140                          * queue_work()
1141                          * ...
1142                          * [vmbus_on_msg_dpc()]
1143                          * schedule_work()  // CHANNELMSG_RESCIND_CHANNELOFFER
1144                          *
1145                          * We rely on the memory-ordering properties of the
1146                          * queue_work() and schedule_work() primitives, which
1147                          * guarantee that the atomic increment will be visible
1148                          * to the CPUs which will execute the offer & rescind
1149                          * works by the time these works will start execution.
1150                          */
1151                         if (vmbus_connection.ignore_any_offer_msg)
1152                                 break;
1153                         atomic_inc(&vmbus_connection.offer_in_progress);
1154                         fallthrough;
1155
1156                 default:
1157                         queue_work(vmbus_connection.work_queue, &ctx->work);
1158                 }
1159         } else
1160                 entry->message_handler(hdr);
1161
1162 msg_handled:
1163         vmbus_signal_eom(msg, message_type);
1164 }
1165
1166 #ifdef CONFIG_PM_SLEEP
1167 /*
1168  * Fake RESCIND_CHANNEL messages to clean up hv_sock channels by force for
1169  * hibernation, because hv_sock connections can not persist across hibernation.
1170  */
1171 static void vmbus_force_channel_rescinded(struct vmbus_channel *channel)
1172 {
1173         struct onmessage_work_context *ctx;
1174         struct vmbus_channel_rescind_offer *rescind;
1175
1176         WARN_ON(!is_hvsock_channel(channel));
1177
1178         /*
1179          * Allocation size is small and the allocation should really not fail,
1180          * otherwise the state of the hv_sock connections ends up in limbo.
1181          */
1182         ctx = kzalloc(sizeof(*ctx) + sizeof(*rescind),
1183                       GFP_KERNEL | __GFP_NOFAIL);
1184
1185         /*
1186          * So far, these are not really used by Linux. Just set them to the
1187          * reasonable values conforming to the definitions of the fields.
1188          */
1189         ctx->msg.header.message_type = 1;
1190         ctx->msg.header.payload_size = sizeof(*rescind);
1191
1192         /* These values are actually used by Linux. */
1193         rescind = (struct vmbus_channel_rescind_offer *)ctx->msg.payload;
1194         rescind->header.msgtype = CHANNELMSG_RESCIND_CHANNELOFFER;
1195         rescind->child_relid = channel->offermsg.child_relid;
1196
1197         INIT_WORK(&ctx->work, vmbus_onmessage_work);
1198
1199         queue_work(vmbus_connection.work_queue, &ctx->work);
1200 }
1201 #endif /* CONFIG_PM_SLEEP */
1202
1203 /*
1204  * Schedule all channels with events pending
1205  */
1206 static void vmbus_chan_sched(struct hv_per_cpu_context *hv_cpu)
1207 {
1208         unsigned long *recv_int_page;
1209         u32 maxbits, relid;
1210
1211         /*
1212          * The event page can be directly checked to get the id of
1213          * the channel that has the interrupt pending.
1214          */
1215         void *page_addr = hv_cpu->synic_event_page;
1216         union hv_synic_event_flags *event
1217                 = (union hv_synic_event_flags *)page_addr +
1218                                          VMBUS_MESSAGE_SINT;
1219
1220         maxbits = HV_EVENT_FLAGS_COUNT;
1221         recv_int_page = event->flags;
1222
1223         if (unlikely(!recv_int_page))
1224                 return;
1225
1226         for_each_set_bit(relid, recv_int_page, maxbits) {
1227                 void (*callback_fn)(void *context);
1228                 struct vmbus_channel *channel;
1229
1230                 if (!sync_test_and_clear_bit(relid, recv_int_page))
1231                         continue;
1232
1233                 /* Special case - vmbus channel protocol msg */
1234                 if (relid == 0)
1235                         continue;
1236
1237                 /*
1238                  * Pairs with the kfree_rcu() in vmbus_chan_release().
1239                  * Guarantees that the channel data structure doesn't
1240                  * get freed while the channel pointer below is being
1241                  * dereferenced.
1242                  */
1243                 rcu_read_lock();
1244
1245                 /* Find channel based on relid */
1246                 channel = relid2channel(relid);
1247                 if (channel == NULL)
1248                         goto sched_unlock_rcu;
1249
1250                 if (channel->rescind)
1251                         goto sched_unlock_rcu;
1252
1253                 /*
1254                  * Make sure that the ring buffer data structure doesn't get
1255                  * freed while we dereference the ring buffer pointer.  Test
1256                  * for the channel's onchannel_callback being NULL within a
1257                  * sched_lock critical section.  See also the inline comments
1258                  * in vmbus_reset_channel_cb().
1259                  */
1260                 spin_lock(&channel->sched_lock);
1261
1262                 callback_fn = channel->onchannel_callback;
1263                 if (unlikely(callback_fn == NULL))
1264                         goto sched_unlock;
1265
1266                 trace_vmbus_chan_sched(channel);
1267
1268                 ++channel->interrupts;
1269
1270                 switch (channel->callback_mode) {
1271                 case HV_CALL_ISR:
1272                         (*callback_fn)(channel->channel_callback_context);
1273                         break;
1274
1275                 case HV_CALL_BATCHED:
1276                         hv_begin_read(&channel->inbound);
1277                         fallthrough;
1278                 case HV_CALL_DIRECT:
1279                         tasklet_schedule(&channel->callback_event);
1280                 }
1281
1282 sched_unlock:
1283                 spin_unlock(&channel->sched_lock);
1284 sched_unlock_rcu:
1285                 rcu_read_unlock();
1286         }
1287 }
1288
1289 static void vmbus_isr(void)
1290 {
1291         struct hv_per_cpu_context *hv_cpu
1292                 = this_cpu_ptr(hv_context.cpu_context);
1293         void *page_addr;
1294         struct hv_message *msg;
1295
1296         vmbus_chan_sched(hv_cpu);
1297
1298         page_addr = hv_cpu->synic_message_page;
1299         msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
1300
1301         /* Check if there are actual msgs to be processed */
1302         if (msg->header.message_type != HVMSG_NONE) {
1303                 if (msg->header.message_type == HVMSG_TIMER_EXPIRED) {
1304                         hv_stimer0_isr();
1305                         vmbus_signal_eom(msg, HVMSG_TIMER_EXPIRED);
1306                 } else
1307                         tasklet_schedule(&hv_cpu->msg_dpc);
1308         }
1309
1310         add_interrupt_randomness(vmbus_interrupt);
1311 }
1312
1313 static irqreturn_t vmbus_percpu_isr(int irq, void *dev_id)
1314 {
1315         vmbus_isr();
1316         return IRQ_HANDLED;
1317 }
1318
1319 /*
1320  * vmbus_bus_init -Main vmbus driver initialization routine.
1321  *
1322  * Here, we
1323  *      - initialize the vmbus driver context
1324  *      - invoke the vmbus hv main init routine
1325  *      - retrieve the channel offers
1326  */
1327 static int vmbus_bus_init(void)
1328 {
1329         int ret;
1330
1331         ret = hv_init();
1332         if (ret != 0) {
1333                 pr_err("Unable to initialize the hypervisor - 0x%x\n", ret);
1334                 return ret;
1335         }
1336
1337         ret = bus_register(&hv_bus);
1338         if (ret)
1339                 return ret;
1340
1341         /*
1342          * VMbus interrupts are best modeled as per-cpu interrupts. If
1343          * on an architecture with support for per-cpu IRQs (e.g. ARM64),
1344          * allocate a per-cpu IRQ using standard Linux kernel functionality.
1345          * If not on such an architecture (e.g., x86/x64), then rely on
1346          * code in the arch-specific portion of the code tree to connect
1347          * the VMbus interrupt handler.
1348          */
1349
1350         if (vmbus_irq == -1) {
1351                 hv_setup_vmbus_handler(vmbus_isr);
1352         } else {
1353                 vmbus_evt = alloc_percpu(long);
1354                 ret = request_percpu_irq(vmbus_irq, vmbus_percpu_isr,
1355                                 "Hyper-V VMbus", vmbus_evt);
1356                 if (ret) {
1357                         pr_err("Can't request Hyper-V VMbus IRQ %d, Err %d",
1358                                         vmbus_irq, ret);
1359                         free_percpu(vmbus_evt);
1360                         goto err_setup;
1361                 }
1362         }
1363
1364         ret = hv_synic_alloc();
1365         if (ret)
1366                 goto err_alloc;
1367
1368         /*
1369          * Initialize the per-cpu interrupt state and stimer state.
1370          * Then connect to the host.
1371          */
1372         ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "hyperv/vmbus:online",
1373                                 hv_synic_init, hv_synic_cleanup);
1374         if (ret < 0)
1375                 goto err_alloc;
1376         hyperv_cpuhp_online = ret;
1377
1378         ret = vmbus_connect();
1379         if (ret)
1380                 goto err_connect;
1381
1382         /*
1383          * Always register the vmbus unload panic notifier because we
1384          * need to shut the VMbus channel connection on panic.
1385          */
1386         atomic_notifier_chain_register(&panic_notifier_list,
1387                                &hyperv_panic_vmbus_unload_block);
1388
1389         vmbus_request_offers();
1390
1391         return 0;
1392
1393 err_connect:
1394         cpuhp_remove_state(hyperv_cpuhp_online);
1395 err_alloc:
1396         hv_synic_free();
1397         if (vmbus_irq == -1) {
1398                 hv_remove_vmbus_handler();
1399         } else {
1400                 free_percpu_irq(vmbus_irq, vmbus_evt);
1401                 free_percpu(vmbus_evt);
1402         }
1403 err_setup:
1404         bus_unregister(&hv_bus);
1405         return ret;
1406 }
1407
1408 /**
1409  * __vmbus_driver_register() - Register a vmbus's driver
1410  * @hv_driver: Pointer to driver structure you want to register
1411  * @owner: owner module of the drv
1412  * @mod_name: module name string
1413  *
1414  * Registers the given driver with Linux through the 'driver_register()' call
1415  * and sets up the hyper-v vmbus handling for this driver.
1416  * It will return the state of the 'driver_register()' call.
1417  *
1418  */
1419 int __vmbus_driver_register(struct hv_driver *hv_driver, struct module *owner, const char *mod_name)
1420 {
1421         int ret;
1422
1423         pr_info("registering driver %s\n", hv_driver->name);
1424
1425         ret = vmbus_exists();
1426         if (ret < 0)
1427                 return ret;
1428
1429         hv_driver->driver.name = hv_driver->name;
1430         hv_driver->driver.owner = owner;
1431         hv_driver->driver.mod_name = mod_name;
1432         hv_driver->driver.bus = &hv_bus;
1433
1434         spin_lock_init(&hv_driver->dynids.lock);
1435         INIT_LIST_HEAD(&hv_driver->dynids.list);
1436
1437         ret = driver_register(&hv_driver->driver);
1438
1439         return ret;
1440 }
1441 EXPORT_SYMBOL_GPL(__vmbus_driver_register);
1442
1443 /**
1444  * vmbus_driver_unregister() - Unregister a vmbus's driver
1445  * @hv_driver: Pointer to driver structure you want to
1446  *             un-register
1447  *
1448  * Un-register the given driver that was previous registered with a call to
1449  * vmbus_driver_register()
1450  */
1451 void vmbus_driver_unregister(struct hv_driver *hv_driver)
1452 {
1453         pr_info("unregistering driver %s\n", hv_driver->name);
1454
1455         if (!vmbus_exists()) {
1456                 driver_unregister(&hv_driver->driver);
1457                 vmbus_free_dynids(hv_driver);
1458         }
1459 }
1460 EXPORT_SYMBOL_GPL(vmbus_driver_unregister);
1461
1462
1463 /*
1464  * Called when last reference to channel is gone.
1465  */
1466 static void vmbus_chan_release(struct kobject *kobj)
1467 {
1468         struct vmbus_channel *channel
1469                 = container_of(kobj, struct vmbus_channel, kobj);
1470
1471         kfree_rcu(channel, rcu);
1472 }
1473
1474 struct vmbus_chan_attribute {
1475         struct attribute attr;
1476         ssize_t (*show)(struct vmbus_channel *chan, char *buf);
1477         ssize_t (*store)(struct vmbus_channel *chan,
1478                          const char *buf, size_t count);
1479 };
1480 #define VMBUS_CHAN_ATTR(_name, _mode, _show, _store) \
1481         struct vmbus_chan_attribute chan_attr_##_name \
1482                 = __ATTR(_name, _mode, _show, _store)
1483 #define VMBUS_CHAN_ATTR_RW(_name) \
1484         struct vmbus_chan_attribute chan_attr_##_name = __ATTR_RW(_name)
1485 #define VMBUS_CHAN_ATTR_RO(_name) \
1486         struct vmbus_chan_attribute chan_attr_##_name = __ATTR_RO(_name)
1487 #define VMBUS_CHAN_ATTR_WO(_name) \
1488         struct vmbus_chan_attribute chan_attr_##_name = __ATTR_WO(_name)
1489
1490 static ssize_t vmbus_chan_attr_show(struct kobject *kobj,
1491                                     struct attribute *attr, char *buf)
1492 {
1493         const struct vmbus_chan_attribute *attribute
1494                 = container_of(attr, struct vmbus_chan_attribute, attr);
1495         struct vmbus_channel *chan
1496                 = container_of(kobj, struct vmbus_channel, kobj);
1497
1498         if (!attribute->show)
1499                 return -EIO;
1500
1501         return attribute->show(chan, buf);
1502 }
1503
1504 static ssize_t vmbus_chan_attr_store(struct kobject *kobj,
1505                                      struct attribute *attr, const char *buf,
1506                                      size_t count)
1507 {
1508         const struct vmbus_chan_attribute *attribute
1509                 = container_of(attr, struct vmbus_chan_attribute, attr);
1510         struct vmbus_channel *chan
1511                 = container_of(kobj, struct vmbus_channel, kobj);
1512
1513         if (!attribute->store)
1514                 return -EIO;
1515
1516         return attribute->store(chan, buf, count);
1517 }
1518
1519 static const struct sysfs_ops vmbus_chan_sysfs_ops = {
1520         .show = vmbus_chan_attr_show,
1521         .store = vmbus_chan_attr_store,
1522 };
1523
1524 static ssize_t out_mask_show(struct vmbus_channel *channel, char *buf)
1525 {
1526         struct hv_ring_buffer_info *rbi = &channel->outbound;
1527         ssize_t ret;
1528
1529         mutex_lock(&rbi->ring_buffer_mutex);
1530         if (!rbi->ring_buffer) {
1531                 mutex_unlock(&rbi->ring_buffer_mutex);
1532                 return -EINVAL;
1533         }
1534
1535         ret = sprintf(buf, "%u\n", rbi->ring_buffer->interrupt_mask);
1536         mutex_unlock(&rbi->ring_buffer_mutex);
1537         return ret;
1538 }
1539 static VMBUS_CHAN_ATTR_RO(out_mask);
1540
1541 static ssize_t in_mask_show(struct vmbus_channel *channel, char *buf)
1542 {
1543         struct hv_ring_buffer_info *rbi = &channel->inbound;
1544         ssize_t ret;
1545
1546         mutex_lock(&rbi->ring_buffer_mutex);
1547         if (!rbi->ring_buffer) {
1548                 mutex_unlock(&rbi->ring_buffer_mutex);
1549                 return -EINVAL;
1550         }
1551
1552         ret = sprintf(buf, "%u\n", rbi->ring_buffer->interrupt_mask);
1553         mutex_unlock(&rbi->ring_buffer_mutex);
1554         return ret;
1555 }
1556 static VMBUS_CHAN_ATTR_RO(in_mask);
1557
1558 static ssize_t read_avail_show(struct vmbus_channel *channel, char *buf)
1559 {
1560         struct hv_ring_buffer_info *rbi = &channel->inbound;
1561         ssize_t ret;
1562
1563         mutex_lock(&rbi->ring_buffer_mutex);
1564         if (!rbi->ring_buffer) {
1565                 mutex_unlock(&rbi->ring_buffer_mutex);
1566                 return -EINVAL;
1567         }
1568
1569         ret = sprintf(buf, "%u\n", hv_get_bytes_to_read(rbi));
1570         mutex_unlock(&rbi->ring_buffer_mutex);
1571         return ret;
1572 }
1573 static VMBUS_CHAN_ATTR_RO(read_avail);
1574
1575 static ssize_t write_avail_show(struct vmbus_channel *channel, char *buf)
1576 {
1577         struct hv_ring_buffer_info *rbi = &channel->outbound;
1578         ssize_t ret;
1579
1580         mutex_lock(&rbi->ring_buffer_mutex);
1581         if (!rbi->ring_buffer) {
1582                 mutex_unlock(&rbi->ring_buffer_mutex);
1583                 return -EINVAL;
1584         }
1585
1586         ret = sprintf(buf, "%u\n", hv_get_bytes_to_write(rbi));
1587         mutex_unlock(&rbi->ring_buffer_mutex);
1588         return ret;
1589 }
1590 static VMBUS_CHAN_ATTR_RO(write_avail);
1591
1592 static ssize_t target_cpu_show(struct vmbus_channel *channel, char *buf)
1593 {
1594         return sprintf(buf, "%u\n", channel->target_cpu);
1595 }
1596 static ssize_t target_cpu_store(struct vmbus_channel *channel,
1597                                 const char *buf, size_t count)
1598 {
1599         u32 target_cpu, origin_cpu;
1600         ssize_t ret = count;
1601
1602         if (vmbus_proto_version < VERSION_WIN10_V4_1)
1603                 return -EIO;
1604
1605         if (sscanf(buf, "%uu", &target_cpu) != 1)
1606                 return -EIO;
1607
1608         /* Validate target_cpu for the cpumask_test_cpu() operation below. */
1609         if (target_cpu >= nr_cpumask_bits)
1610                 return -EINVAL;
1611
1612         if (!cpumask_test_cpu(target_cpu, housekeeping_cpumask(HK_TYPE_MANAGED_IRQ)))
1613                 return -EINVAL;
1614
1615         /* No CPUs should come up or down during this. */
1616         cpus_read_lock();
1617
1618         if (!cpu_online(target_cpu)) {
1619                 cpus_read_unlock();
1620                 return -EINVAL;
1621         }
1622
1623         /*
1624          * Synchronizes target_cpu_store() and channel closure:
1625          *
1626          * { Initially: state = CHANNEL_OPENED }
1627          *
1628          * CPU1                         CPU2
1629          *
1630          * [target_cpu_store()]         [vmbus_disconnect_ring()]
1631          *
1632          * LOCK channel_mutex           LOCK channel_mutex
1633          * LOAD r1 = state              LOAD r2 = state
1634          * IF (r1 == CHANNEL_OPENED)    IF (r2 == CHANNEL_OPENED)
1635          *   SEND MODIFYCHANNEL           STORE state = CHANNEL_OPEN
1636          *   [...]                        SEND CLOSECHANNEL
1637          * UNLOCK channel_mutex         UNLOCK channel_mutex
1638          *
1639          * Forbids: r1 == r2 == CHANNEL_OPENED (i.e., CPU1's LOCK precedes
1640          *              CPU2's LOCK) && CPU2's SEND precedes CPU1's SEND
1641          *
1642          * Note.  The host processes the channel messages "sequentially", in
1643          * the order in which they are received on a per-partition basis.
1644          */
1645         mutex_lock(&vmbus_connection.channel_mutex);
1646
1647         /*
1648          * Hyper-V will ignore MODIFYCHANNEL messages for "non-open" channels;
1649          * avoid sending the message and fail here for such channels.
1650          */
1651         if (channel->state != CHANNEL_OPENED_STATE) {
1652                 ret = -EIO;
1653                 goto cpu_store_unlock;
1654         }
1655
1656         origin_cpu = channel->target_cpu;
1657         if (target_cpu == origin_cpu)
1658                 goto cpu_store_unlock;
1659
1660         if (vmbus_send_modifychannel(channel,
1661                                      hv_cpu_number_to_vp_number(target_cpu))) {
1662                 ret = -EIO;
1663                 goto cpu_store_unlock;
1664         }
1665
1666         /*
1667          * For version before VERSION_WIN10_V5_3, the following warning holds:
1668          *
1669          * Warning.  At this point, there is *no* guarantee that the host will
1670          * have successfully processed the vmbus_send_modifychannel() request.
1671          * See the header comment of vmbus_send_modifychannel() for more info.
1672          *
1673          * Lags in the processing of the above vmbus_send_modifychannel() can
1674          * result in missed interrupts if the "old" target CPU is taken offline
1675          * before Hyper-V starts sending interrupts to the "new" target CPU.
1676          * But apart from this offlining scenario, the code tolerates such
1677          * lags.  It will function correctly even if a channel interrupt comes
1678          * in on a CPU that is different from the channel target_cpu value.
1679          */
1680
1681         channel->target_cpu = target_cpu;
1682
1683         /* See init_vp_index(). */
1684         if (hv_is_perf_channel(channel))
1685                 hv_update_allocated_cpus(origin_cpu, target_cpu);
1686
1687         /* Currently set only for storvsc channels. */
1688         if (channel->change_target_cpu_callback) {
1689                 (*channel->change_target_cpu_callback)(channel,
1690                                 origin_cpu, target_cpu);
1691         }
1692
1693 cpu_store_unlock:
1694         mutex_unlock(&vmbus_connection.channel_mutex);
1695         cpus_read_unlock();
1696         return ret;
1697 }
1698 static VMBUS_CHAN_ATTR(cpu, 0644, target_cpu_show, target_cpu_store);
1699
1700 static ssize_t channel_pending_show(struct vmbus_channel *channel,
1701                                     char *buf)
1702 {
1703         return sprintf(buf, "%d\n",
1704                        channel_pending(channel,
1705                                        vmbus_connection.monitor_pages[1]));
1706 }
1707 static VMBUS_CHAN_ATTR(pending, 0444, channel_pending_show, NULL);
1708
1709 static ssize_t channel_latency_show(struct vmbus_channel *channel,
1710                                     char *buf)
1711 {
1712         return sprintf(buf, "%d\n",
1713                        channel_latency(channel,
1714                                        vmbus_connection.monitor_pages[1]));
1715 }
1716 static VMBUS_CHAN_ATTR(latency, 0444, channel_latency_show, NULL);
1717
1718 static ssize_t channel_interrupts_show(struct vmbus_channel *channel, char *buf)
1719 {
1720         return sprintf(buf, "%llu\n", channel->interrupts);
1721 }
1722 static VMBUS_CHAN_ATTR(interrupts, 0444, channel_interrupts_show, NULL);
1723
1724 static ssize_t channel_events_show(struct vmbus_channel *channel, char *buf)
1725 {
1726         return sprintf(buf, "%llu\n", channel->sig_events);
1727 }
1728 static VMBUS_CHAN_ATTR(events, 0444, channel_events_show, NULL);
1729
1730 static ssize_t channel_intr_in_full_show(struct vmbus_channel *channel,
1731                                          char *buf)
1732 {
1733         return sprintf(buf, "%llu\n",
1734                        (unsigned long long)channel->intr_in_full);
1735 }
1736 static VMBUS_CHAN_ATTR(intr_in_full, 0444, channel_intr_in_full_show, NULL);
1737
1738 static ssize_t channel_intr_out_empty_show(struct vmbus_channel *channel,
1739                                            char *buf)
1740 {
1741         return sprintf(buf, "%llu\n",
1742                        (unsigned long long)channel->intr_out_empty);
1743 }
1744 static VMBUS_CHAN_ATTR(intr_out_empty, 0444, channel_intr_out_empty_show, NULL);
1745
1746 static ssize_t channel_out_full_first_show(struct vmbus_channel *channel,
1747                                            char *buf)
1748 {
1749         return sprintf(buf, "%llu\n",
1750                        (unsigned long long)channel->out_full_first);
1751 }
1752 static VMBUS_CHAN_ATTR(out_full_first, 0444, channel_out_full_first_show, NULL);
1753
1754 static ssize_t channel_out_full_total_show(struct vmbus_channel *channel,
1755                                            char *buf)
1756 {
1757         return sprintf(buf, "%llu\n",
1758                        (unsigned long long)channel->out_full_total);
1759 }
1760 static VMBUS_CHAN_ATTR(out_full_total, 0444, channel_out_full_total_show, NULL);
1761
1762 static ssize_t subchannel_monitor_id_show(struct vmbus_channel *channel,
1763                                           char *buf)
1764 {
1765         return sprintf(buf, "%u\n", channel->offermsg.monitorid);
1766 }
1767 static VMBUS_CHAN_ATTR(monitor_id, 0444, subchannel_monitor_id_show, NULL);
1768
1769 static ssize_t subchannel_id_show(struct vmbus_channel *channel,
1770                                   char *buf)
1771 {
1772         return sprintf(buf, "%u\n",
1773                        channel->offermsg.offer.sub_channel_index);
1774 }
1775 static VMBUS_CHAN_ATTR_RO(subchannel_id);
1776
1777 static struct attribute *vmbus_chan_attrs[] = {
1778         &chan_attr_out_mask.attr,
1779         &chan_attr_in_mask.attr,
1780         &chan_attr_read_avail.attr,
1781         &chan_attr_write_avail.attr,
1782         &chan_attr_cpu.attr,
1783         &chan_attr_pending.attr,
1784         &chan_attr_latency.attr,
1785         &chan_attr_interrupts.attr,
1786         &chan_attr_events.attr,
1787         &chan_attr_intr_in_full.attr,
1788         &chan_attr_intr_out_empty.attr,
1789         &chan_attr_out_full_first.attr,
1790         &chan_attr_out_full_total.attr,
1791         &chan_attr_monitor_id.attr,
1792         &chan_attr_subchannel_id.attr,
1793         NULL
1794 };
1795
1796 /*
1797  * Channel-level attribute_group callback function. Returns the permission for
1798  * each attribute, and returns 0 if an attribute is not visible.
1799  */
1800 static umode_t vmbus_chan_attr_is_visible(struct kobject *kobj,
1801                                           struct attribute *attr, int idx)
1802 {
1803         const struct vmbus_channel *channel =
1804                 container_of(kobj, struct vmbus_channel, kobj);
1805
1806         /* Hide the monitor attributes if the monitor mechanism is not used. */
1807         if (!channel->offermsg.monitor_allocated &&
1808             (attr == &chan_attr_pending.attr ||
1809              attr == &chan_attr_latency.attr ||
1810              attr == &chan_attr_monitor_id.attr))
1811                 return 0;
1812
1813         return attr->mode;
1814 }
1815
1816 static struct attribute_group vmbus_chan_group = {
1817         .attrs = vmbus_chan_attrs,
1818         .is_visible = vmbus_chan_attr_is_visible
1819 };
1820
1821 static struct kobj_type vmbus_chan_ktype = {
1822         .sysfs_ops = &vmbus_chan_sysfs_ops,
1823         .release = vmbus_chan_release,
1824 };
1825
1826 /*
1827  * vmbus_add_channel_kobj - setup a sub-directory under device/channels
1828  */
1829 int vmbus_add_channel_kobj(struct hv_device *dev, struct vmbus_channel *channel)
1830 {
1831         const struct device *device = &dev->device;
1832         struct kobject *kobj = &channel->kobj;
1833         u32 relid = channel->offermsg.child_relid;
1834         int ret;
1835
1836         kobj->kset = dev->channels_kset;
1837         ret = kobject_init_and_add(kobj, &vmbus_chan_ktype, NULL,
1838                                    "%u", relid);
1839         if (ret) {
1840                 kobject_put(kobj);
1841                 return ret;
1842         }
1843
1844         ret = sysfs_create_group(kobj, &vmbus_chan_group);
1845
1846         if (ret) {
1847                 /*
1848                  * The calling functions' error handling paths will cleanup the
1849                  * empty channel directory.
1850                  */
1851                 kobject_put(kobj);
1852                 dev_err(device, "Unable to set up channel sysfs files\n");
1853                 return ret;
1854         }
1855
1856         kobject_uevent(kobj, KOBJ_ADD);
1857
1858         return 0;
1859 }
1860
1861 /*
1862  * vmbus_remove_channel_attr_group - remove the channel's attribute group
1863  */
1864 void vmbus_remove_channel_attr_group(struct vmbus_channel *channel)
1865 {
1866         sysfs_remove_group(&channel->kobj, &vmbus_chan_group);
1867 }
1868
1869 /*
1870  * vmbus_device_create - Creates and registers a new child device
1871  * on the vmbus.
1872  */
1873 struct hv_device *vmbus_device_create(const guid_t *type,
1874                                       const guid_t *instance,
1875                                       struct vmbus_channel *channel)
1876 {
1877         struct hv_device *child_device_obj;
1878
1879         child_device_obj = kzalloc(sizeof(struct hv_device), GFP_KERNEL);
1880         if (!child_device_obj) {
1881                 pr_err("Unable to allocate device object for child device\n");
1882                 return NULL;
1883         }
1884
1885         child_device_obj->channel = channel;
1886         guid_copy(&child_device_obj->dev_type, type);
1887         guid_copy(&child_device_obj->dev_instance, instance);
1888         child_device_obj->vendor_id = PCI_VENDOR_ID_MICROSOFT;
1889
1890         return child_device_obj;
1891 }
1892
1893 /*
1894  * vmbus_device_register - Register the child device
1895  */
1896 int vmbus_device_register(struct hv_device *child_device_obj)
1897 {
1898         struct kobject *kobj = &child_device_obj->device.kobj;
1899         int ret;
1900
1901         dev_set_name(&child_device_obj->device, "%pUl",
1902                      &child_device_obj->channel->offermsg.offer.if_instance);
1903
1904         child_device_obj->device.bus = &hv_bus;
1905         child_device_obj->device.parent = hv_dev;
1906         child_device_obj->device.release = vmbus_device_release;
1907
1908         child_device_obj->device.dma_parms = &child_device_obj->dma_parms;
1909         child_device_obj->device.dma_mask = &child_device_obj->dma_mask;
1910         dma_set_mask(&child_device_obj->device, DMA_BIT_MASK(64));
1911
1912         /*
1913          * Register with the LDM. This will kick off the driver/device
1914          * binding...which will eventually call vmbus_match() and vmbus_probe()
1915          */
1916         ret = device_register(&child_device_obj->device);
1917         if (ret) {
1918                 pr_err("Unable to register child device\n");
1919                 put_device(&child_device_obj->device);
1920                 return ret;
1921         }
1922
1923         child_device_obj->channels_kset = kset_create_and_add("channels",
1924                                                               NULL, kobj);
1925         if (!child_device_obj->channels_kset) {
1926                 ret = -ENOMEM;
1927                 goto err_dev_unregister;
1928         }
1929
1930         ret = vmbus_add_channel_kobj(child_device_obj,
1931                                      child_device_obj->channel);
1932         if (ret) {
1933                 pr_err("Unable to register primary channeln");
1934                 goto err_kset_unregister;
1935         }
1936         hv_debug_add_dev_dir(child_device_obj);
1937
1938         return 0;
1939
1940 err_kset_unregister:
1941         kset_unregister(child_device_obj->channels_kset);
1942
1943 err_dev_unregister:
1944         device_unregister(&child_device_obj->device);
1945         return ret;
1946 }
1947
1948 /*
1949  * vmbus_device_unregister - Remove the specified child device
1950  * from the vmbus.
1951  */
1952 void vmbus_device_unregister(struct hv_device *device_obj)
1953 {
1954         pr_debug("child device %s unregistered\n",
1955                 dev_name(&device_obj->device));
1956
1957         kset_unregister(device_obj->channels_kset);
1958
1959         /*
1960          * Kick off the process of unregistering the device.
1961          * This will call vmbus_remove() and eventually vmbus_device_release()
1962          */
1963         device_unregister(&device_obj->device);
1964 }
1965
1966 #ifdef CONFIG_ACPI
1967 /*
1968  * VMBUS is an acpi enumerated device. Get the information we
1969  * need from DSDT.
1970  */
1971 static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *ctx)
1972 {
1973         resource_size_t start = 0;
1974         resource_size_t end = 0;
1975         struct resource *new_res;
1976         struct resource **old_res = &hyperv_mmio;
1977         struct resource **prev_res = NULL;
1978         struct resource r;
1979
1980         switch (res->type) {
1981
1982         /*
1983          * "Address" descriptors are for bus windows. Ignore
1984          * "memory" descriptors, which are for registers on
1985          * devices.
1986          */
1987         case ACPI_RESOURCE_TYPE_ADDRESS32:
1988                 start = res->data.address32.address.minimum;
1989                 end = res->data.address32.address.maximum;
1990                 break;
1991
1992         case ACPI_RESOURCE_TYPE_ADDRESS64:
1993                 start = res->data.address64.address.minimum;
1994                 end = res->data.address64.address.maximum;
1995                 break;
1996
1997         /*
1998          * The IRQ information is needed only on ARM64, which Hyper-V
1999          * sets up in the extended format. IRQ information is present
2000          * on x86/x64 in the non-extended format but it is not used by
2001          * Linux. So don't bother checking for the non-extended format.
2002          */
2003         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
2004                 if (!acpi_dev_resource_interrupt(res, 0, &r)) {
2005                         pr_err("Unable to parse Hyper-V ACPI interrupt\n");
2006                         return AE_ERROR;
2007                 }
2008                 /* ARM64 INTID for VMbus */
2009                 vmbus_interrupt = res->data.extended_irq.interrupts[0];
2010                 /* Linux IRQ number */
2011                 vmbus_irq = r.start;
2012                 return AE_OK;
2013
2014         default:
2015                 /* Unused resource type */
2016                 return AE_OK;
2017
2018         }
2019         /*
2020          * Ignore ranges that are below 1MB, as they're not
2021          * necessary or useful here.
2022          */
2023         if (end < 0x100000)
2024                 return AE_OK;
2025
2026         new_res = kzalloc(sizeof(*new_res), GFP_ATOMIC);
2027         if (!new_res)
2028                 return AE_NO_MEMORY;
2029
2030         /* If this range overlaps the virtual TPM, truncate it. */
2031         if (end > VTPM_BASE_ADDRESS && start < VTPM_BASE_ADDRESS)
2032                 end = VTPM_BASE_ADDRESS;
2033
2034         new_res->name = "hyperv mmio";
2035         new_res->flags = IORESOURCE_MEM;
2036         new_res->start = start;
2037         new_res->end = end;
2038
2039         /*
2040          * If two ranges are adjacent, merge them.
2041          */
2042         do {
2043                 if (!*old_res) {
2044                         *old_res = new_res;
2045                         break;
2046                 }
2047
2048                 if (((*old_res)->end + 1) == new_res->start) {
2049                         (*old_res)->end = new_res->end;
2050                         kfree(new_res);
2051                         break;
2052                 }
2053
2054                 if ((*old_res)->start == new_res->end + 1) {
2055                         (*old_res)->start = new_res->start;
2056                         kfree(new_res);
2057                         break;
2058                 }
2059
2060                 if ((*old_res)->start > new_res->end) {
2061                         new_res->sibling = *old_res;
2062                         if (prev_res)
2063                                 (*prev_res)->sibling = new_res;
2064                         *old_res = new_res;
2065                         break;
2066                 }
2067
2068                 prev_res = old_res;
2069                 old_res = &(*old_res)->sibling;
2070
2071         } while (1);
2072
2073         return AE_OK;
2074 }
2075 #endif
2076
2077 static void vmbus_mmio_remove(void)
2078 {
2079         struct resource *cur_res;
2080         struct resource *next_res;
2081
2082         if (hyperv_mmio) {
2083                 if (fb_mmio) {
2084                         __release_region(hyperv_mmio, fb_mmio->start,
2085                                          resource_size(fb_mmio));
2086                         fb_mmio = NULL;
2087                 }
2088
2089                 for (cur_res = hyperv_mmio; cur_res; cur_res = next_res) {
2090                         next_res = cur_res->sibling;
2091                         kfree(cur_res);
2092                 }
2093         }
2094 }
2095
2096 static void __maybe_unused vmbus_reserve_fb(void)
2097 {
2098         resource_size_t start = 0, size;
2099         struct pci_dev *pdev;
2100
2101         if (efi_enabled(EFI_BOOT)) {
2102                 /* Gen2 VM: get FB base from EFI framebuffer */
2103                 if (IS_ENABLED(CONFIG_SYSFB)) {
2104                         start = screen_info.lfb_base;
2105                         size = max_t(__u32, screen_info.lfb_size, 0x800000);
2106                 }
2107         } else {
2108                 /* Gen1 VM: get FB base from PCI */
2109                 pdev = pci_get_device(PCI_VENDOR_ID_MICROSOFT,
2110                                       PCI_DEVICE_ID_HYPERV_VIDEO, NULL);
2111                 if (!pdev)
2112                         return;
2113
2114                 if (pdev->resource[0].flags & IORESOURCE_MEM) {
2115                         start = pci_resource_start(pdev, 0);
2116                         size = pci_resource_len(pdev, 0);
2117                 }
2118
2119                 /*
2120                  * Release the PCI device so hyperv_drm or hyperv_fb driver can
2121                  * grab it later.
2122                  */
2123                 pci_dev_put(pdev);
2124         }
2125
2126         if (!start)
2127                 return;
2128
2129         /*
2130          * Make a claim for the frame buffer in the resource tree under the
2131          * first node, which will be the one below 4GB.  The length seems to
2132          * be underreported, particularly in a Generation 1 VM.  So start out
2133          * reserving a larger area and make it smaller until it succeeds.
2134          */
2135         for (; !fb_mmio && (size >= 0x100000); size >>= 1)
2136                 fb_mmio = __request_region(hyperv_mmio, start, size, fb_mmio_name, 0);
2137 }
2138
2139 /**
2140  * vmbus_allocate_mmio() - Pick a memory-mapped I/O range.
2141  * @new:                If successful, supplied a pointer to the
2142  *                      allocated MMIO space.
2143  * @device_obj:         Identifies the caller
2144  * @min:                Minimum guest physical address of the
2145  *                      allocation
2146  * @max:                Maximum guest physical address
2147  * @size:               Size of the range to be allocated
2148  * @align:              Alignment of the range to be allocated
2149  * @fb_overlap_ok:      Whether this allocation can be allowed
2150  *                      to overlap the video frame buffer.
2151  *
2152  * This function walks the resources granted to VMBus by the
2153  * _CRS object in the ACPI namespace underneath the parent
2154  * "bridge" whether that's a root PCI bus in the Generation 1
2155  * case or a Module Device in the Generation 2 case.  It then
2156  * attempts to allocate from the global MMIO pool in a way that
2157  * matches the constraints supplied in these parameters and by
2158  * that _CRS.
2159  *
2160  * Return: 0 on success, -errno on failure
2161  */
2162 int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
2163                         resource_size_t min, resource_size_t max,
2164                         resource_size_t size, resource_size_t align,
2165                         bool fb_overlap_ok)
2166 {
2167         struct resource *iter, *shadow;
2168         resource_size_t range_min, range_max, start, end;
2169         const char *dev_n = dev_name(&device_obj->device);
2170         int retval;
2171
2172         retval = -ENXIO;
2173         mutex_lock(&hyperv_mmio_lock);
2174
2175         /*
2176          * If overlaps with frame buffers are allowed, then first attempt to
2177          * make the allocation from within the reserved region.  Because it
2178          * is already reserved, no shadow allocation is necessary.
2179          */
2180         if (fb_overlap_ok && fb_mmio && !(min > fb_mmio->end) &&
2181             !(max < fb_mmio->start)) {
2182
2183                 range_min = fb_mmio->start;
2184                 range_max = fb_mmio->end;
2185                 start = (range_min + align - 1) & ~(align - 1);
2186                 for (; start + size - 1 <= range_max; start += align) {
2187                         *new = request_mem_region_exclusive(start, size, dev_n);
2188                         if (*new) {
2189                                 retval = 0;
2190                                 goto exit;
2191                         }
2192                 }
2193         }
2194
2195         for (iter = hyperv_mmio; iter; iter = iter->sibling) {
2196                 if ((iter->start >= max) || (iter->end <= min))
2197                         continue;
2198
2199                 range_min = iter->start;
2200                 range_max = iter->end;
2201                 start = (range_min + align - 1) & ~(align - 1);
2202                 for (; start + size - 1 <= range_max; start += align) {
2203                         end = start + size - 1;
2204
2205                         /* Skip the whole fb_mmio region if not fb_overlap_ok */
2206                         if (!fb_overlap_ok && fb_mmio &&
2207                             (((start >= fb_mmio->start) && (start <= fb_mmio->end)) ||
2208                              ((end >= fb_mmio->start) && (end <= fb_mmio->end))))
2209                                 continue;
2210
2211                         shadow = __request_region(iter, start, size, NULL,
2212                                                   IORESOURCE_BUSY);
2213                         if (!shadow)
2214                                 continue;
2215
2216                         *new = request_mem_region_exclusive(start, size, dev_n);
2217                         if (*new) {
2218                                 shadow->name = (char *)*new;
2219                                 retval = 0;
2220                                 goto exit;
2221                         }
2222
2223                         __release_region(iter, start, size);
2224                 }
2225         }
2226
2227 exit:
2228         mutex_unlock(&hyperv_mmio_lock);
2229         return retval;
2230 }
2231 EXPORT_SYMBOL_GPL(vmbus_allocate_mmio);
2232
2233 /**
2234  * vmbus_free_mmio() - Free a memory-mapped I/O range.
2235  * @start:              Base address of region to release.
2236  * @size:               Size of the range to be allocated
2237  *
2238  * This function releases anything requested by
2239  * vmbus_mmio_allocate().
2240  */
2241 void vmbus_free_mmio(resource_size_t start, resource_size_t size)
2242 {
2243         struct resource *iter;
2244
2245         mutex_lock(&hyperv_mmio_lock);
2246         for (iter = hyperv_mmio; iter; iter = iter->sibling) {
2247                 if ((iter->start >= start + size) || (iter->end <= start))
2248                         continue;
2249
2250                 __release_region(iter, start, size);
2251         }
2252         release_mem_region(start, size);
2253         mutex_unlock(&hyperv_mmio_lock);
2254
2255 }
2256 EXPORT_SYMBOL_GPL(vmbus_free_mmio);
2257
2258 #ifdef CONFIG_ACPI
2259 static int vmbus_acpi_add(struct platform_device *pdev)
2260 {
2261         acpi_status result;
2262         int ret_val = -ENODEV;
2263         struct acpi_device *ancestor;
2264         struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
2265
2266         hv_dev = &device->dev;
2267
2268         /*
2269          * Older versions of Hyper-V for ARM64 fail to include the _CCA
2270          * method on the top level VMbus device in the DSDT. But devices
2271          * are hardware coherent in all current Hyper-V use cases, so fix
2272          * up the ACPI device to behave as if _CCA is present and indicates
2273          * hardware coherence.
2274          */
2275         ACPI_COMPANION_SET(&device->dev, device);
2276         if (IS_ENABLED(CONFIG_ACPI_CCA_REQUIRED) &&
2277             device_get_dma_attr(&device->dev) == DEV_DMA_NOT_SUPPORTED) {
2278                 pr_info("No ACPI _CCA found; assuming coherent device I/O\n");
2279                 device->flags.cca_seen = true;
2280                 device->flags.coherent_dma = true;
2281         }
2282
2283         result = acpi_walk_resources(device->handle, METHOD_NAME__CRS,
2284                                         vmbus_walk_resources, NULL);
2285
2286         if (ACPI_FAILURE(result))
2287                 goto acpi_walk_err;
2288         /*
2289          * Some ancestor of the vmbus acpi device (Gen1 or Gen2
2290          * firmware) is the VMOD that has the mmio ranges. Get that.
2291          */
2292         for (ancestor = acpi_dev_parent(device);
2293              ancestor && ancestor->handle != ACPI_ROOT_OBJECT;
2294              ancestor = acpi_dev_parent(ancestor)) {
2295                 result = acpi_walk_resources(ancestor->handle, METHOD_NAME__CRS,
2296                                              vmbus_walk_resources, NULL);
2297
2298                 if (ACPI_FAILURE(result))
2299                         continue;
2300                 if (hyperv_mmio) {
2301                         vmbus_reserve_fb();
2302                         break;
2303                 }
2304         }
2305         ret_val = 0;
2306
2307 acpi_walk_err:
2308         if (ret_val)
2309                 vmbus_mmio_remove();
2310         return ret_val;
2311 }
2312 #else
2313 static int vmbus_acpi_add(struct platform_device *pdev)
2314 {
2315         return 0;
2316 }
2317 #endif
2318
2319 static int vmbus_device_add(struct platform_device *pdev)
2320 {
2321         struct resource **cur_res = &hyperv_mmio;
2322         struct of_range range;
2323         struct of_range_parser parser;
2324         struct device_node *np = pdev->dev.of_node;
2325         int ret;
2326
2327         hv_dev = &pdev->dev;
2328
2329         ret = of_range_parser_init(&parser, np);
2330         if (ret)
2331                 return ret;
2332
2333         for_each_of_range(&parser, &range) {
2334                 struct resource *res;
2335
2336                 res = kzalloc(sizeof(*res), GFP_KERNEL);
2337                 if (!res) {
2338                         vmbus_mmio_remove();
2339                         return -ENOMEM;
2340                 }
2341
2342                 res->name = "hyperv mmio";
2343                 res->flags = range.flags;
2344                 res->start = range.cpu_addr;
2345                 res->end = range.cpu_addr + range.size;
2346
2347                 *cur_res = res;
2348                 cur_res = &res->sibling;
2349         }
2350
2351         return ret;
2352 }
2353
2354 static int vmbus_platform_driver_probe(struct platform_device *pdev)
2355 {
2356         if (acpi_disabled)
2357                 return vmbus_device_add(pdev);
2358         else
2359                 return vmbus_acpi_add(pdev);
2360 }
2361
2362 static void vmbus_platform_driver_remove(struct platform_device *pdev)
2363 {
2364         vmbus_mmio_remove();
2365 }
2366
2367 #ifdef CONFIG_PM_SLEEP
2368 static int vmbus_bus_suspend(struct device *dev)
2369 {
2370         struct hv_per_cpu_context *hv_cpu = per_cpu_ptr(
2371                         hv_context.cpu_context, VMBUS_CONNECT_CPU);
2372         struct vmbus_channel *channel, *sc;
2373
2374         tasklet_disable(&hv_cpu->msg_dpc);
2375         vmbus_connection.ignore_any_offer_msg = true;
2376         /* The tasklet_enable() takes care of providing a memory barrier */
2377         tasklet_enable(&hv_cpu->msg_dpc);
2378
2379         /* Drain all the workqueues as we are in suspend */
2380         drain_workqueue(vmbus_connection.rescind_work_queue);
2381         drain_workqueue(vmbus_connection.work_queue);
2382         drain_workqueue(vmbus_connection.handle_primary_chan_wq);
2383         drain_workqueue(vmbus_connection.handle_sub_chan_wq);
2384
2385         mutex_lock(&vmbus_connection.channel_mutex);
2386         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
2387                 if (!is_hvsock_channel(channel))
2388                         continue;
2389
2390                 vmbus_force_channel_rescinded(channel);
2391         }
2392         mutex_unlock(&vmbus_connection.channel_mutex);
2393
2394         /*
2395          * Wait until all the sub-channels and hv_sock channels have been
2396          * cleaned up. Sub-channels should be destroyed upon suspend, otherwise
2397          * they would conflict with the new sub-channels that will be created
2398          * in the resume path. hv_sock channels should also be destroyed, but
2399          * a hv_sock channel of an established hv_sock connection can not be
2400          * really destroyed since it may still be referenced by the userspace
2401          * application, so we just force the hv_sock channel to be rescinded
2402          * by vmbus_force_channel_rescinded(), and the userspace application
2403          * will thoroughly destroy the channel after hibernation.
2404          *
2405          * Note: the counter nr_chan_close_on_suspend may never go above 0 if
2406          * the VM has no sub-channel and hv_sock channel, e.g. a 1-vCPU VM.
2407          */
2408         if (atomic_read(&vmbus_connection.nr_chan_close_on_suspend) > 0)
2409                 wait_for_completion(&vmbus_connection.ready_for_suspend_event);
2410
2411         if (atomic_read(&vmbus_connection.nr_chan_fixup_on_resume) != 0) {
2412                 pr_err("Can not suspend due to a previous failed resuming\n");
2413                 return -EBUSY;
2414         }
2415
2416         mutex_lock(&vmbus_connection.channel_mutex);
2417
2418         list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
2419                 /*
2420                  * Remove the channel from the array of channels and invalidate
2421                  * the channel's relid.  Upon resume, vmbus_onoffer() will fix
2422                  * up the relid (and other fields, if necessary) and add the
2423                  * channel back to the array.
2424                  */
2425                 vmbus_channel_unmap_relid(channel);
2426                 channel->offermsg.child_relid = INVALID_RELID;
2427
2428                 if (is_hvsock_channel(channel)) {
2429                         if (!channel->rescind) {
2430                                 pr_err("hv_sock channel not rescinded!\n");
2431                                 WARN_ON_ONCE(1);
2432                         }
2433                         continue;
2434                 }
2435
2436                 list_for_each_entry(sc, &channel->sc_list, sc_list) {
2437                         pr_err("Sub-channel not deleted!\n");
2438                         WARN_ON_ONCE(1);
2439                 }
2440
2441                 atomic_inc(&vmbus_connection.nr_chan_fixup_on_resume);
2442         }
2443
2444         mutex_unlock(&vmbus_connection.channel_mutex);
2445
2446         vmbus_initiate_unload(false);
2447
2448         /* Reset the event for the next resume. */
2449         reinit_completion(&vmbus_connection.ready_for_resume_event);
2450
2451         return 0;
2452 }
2453
2454 static int vmbus_bus_resume(struct device *dev)
2455 {
2456         struct vmbus_channel_msginfo *msginfo;
2457         size_t msgsize;
2458         int ret;
2459
2460         vmbus_connection.ignore_any_offer_msg = false;
2461
2462         /*
2463          * We only use the 'vmbus_proto_version', which was in use before
2464          * hibernation, to re-negotiate with the host.
2465          */
2466         if (!vmbus_proto_version) {
2467                 pr_err("Invalid proto version = 0x%x\n", vmbus_proto_version);
2468                 return -EINVAL;
2469         }
2470
2471         msgsize = sizeof(*msginfo) +
2472                   sizeof(struct vmbus_channel_initiate_contact);
2473
2474         msginfo = kzalloc(msgsize, GFP_KERNEL);
2475
2476         if (msginfo == NULL)
2477                 return -ENOMEM;
2478
2479         ret = vmbus_negotiate_version(msginfo, vmbus_proto_version);
2480
2481         kfree(msginfo);
2482
2483         if (ret != 0)
2484                 return ret;
2485
2486         WARN_ON(atomic_read(&vmbus_connection.nr_chan_fixup_on_resume) == 0);
2487
2488         vmbus_request_offers();
2489
2490         if (wait_for_completion_timeout(
2491                 &vmbus_connection.ready_for_resume_event, 10 * HZ) == 0)
2492                 pr_err("Some vmbus device is missing after suspending?\n");
2493
2494         /* Reset the event for the next suspend. */
2495         reinit_completion(&vmbus_connection.ready_for_suspend_event);
2496
2497         return 0;
2498 }
2499 #else
2500 #define vmbus_bus_suspend NULL
2501 #define vmbus_bus_resume NULL
2502 #endif /* CONFIG_PM_SLEEP */
2503
2504 static const __maybe_unused struct of_device_id vmbus_of_match[] = {
2505         {
2506                 .compatible = "microsoft,vmbus",
2507         },
2508         {
2509                 /* sentinel */
2510         },
2511 };
2512 MODULE_DEVICE_TABLE(of, vmbus_of_match);
2513
2514 static const __maybe_unused struct acpi_device_id vmbus_acpi_device_ids[] = {
2515         {"VMBUS", 0},
2516         {"VMBus", 0},
2517         {"", 0},
2518 };
2519 MODULE_DEVICE_TABLE(acpi, vmbus_acpi_device_ids);
2520
2521 /*
2522  * Note: we must use the "no_irq" ops, otherwise hibernation can not work with
2523  * PCI device assignment, because "pci_dev_pm_ops" uses the "noirq" ops: in
2524  * the resume path, the pci "noirq" restore op runs before "non-noirq" op (see
2525  * resume_target_kernel() -> dpm_resume_start(), and hibernation_restore() ->
2526  * dpm_resume_end()). This means vmbus_bus_resume() and the pci-hyperv's
2527  * resume callback must also run via the "noirq" ops.
2528  *
2529  * Set suspend_noirq/resume_noirq to NULL for Suspend-to-Idle: see the comment
2530  * earlier in this file before vmbus_pm.
2531  */
2532
2533 static const struct dev_pm_ops vmbus_bus_pm = {
2534         .suspend_noirq  = NULL,
2535         .resume_noirq   = NULL,
2536         .freeze_noirq   = vmbus_bus_suspend,
2537         .thaw_noirq     = vmbus_bus_resume,
2538         .poweroff_noirq = vmbus_bus_suspend,
2539         .restore_noirq  = vmbus_bus_resume
2540 };
2541
2542 static struct platform_driver vmbus_platform_driver = {
2543         .probe = vmbus_platform_driver_probe,
2544         .remove_new = vmbus_platform_driver_remove,
2545         .driver = {
2546                 .name = "vmbus",
2547                 .acpi_match_table = ACPI_PTR(vmbus_acpi_device_ids),
2548                 .of_match_table = of_match_ptr(vmbus_of_match),
2549                 .pm = &vmbus_bus_pm,
2550                 .probe_type = PROBE_FORCE_SYNCHRONOUS,
2551         }
2552 };
2553
2554 static void hv_kexec_handler(void)
2555 {
2556         hv_stimer_global_cleanup();
2557         vmbus_initiate_unload(false);
2558         /* Make sure conn_state is set as hv_synic_cleanup checks for it */
2559         mb();
2560         cpuhp_remove_state(hyperv_cpuhp_online);
2561 };
2562
2563 static void hv_crash_handler(struct pt_regs *regs)
2564 {
2565         int cpu;
2566
2567         vmbus_initiate_unload(true);
2568         /*
2569          * In crash handler we can't schedule synic cleanup for all CPUs,
2570          * doing the cleanup for current CPU only. This should be sufficient
2571          * for kdump.
2572          */
2573         cpu = smp_processor_id();
2574         hv_stimer_cleanup(cpu);
2575         hv_synic_disable_regs(cpu);
2576 };
2577
2578 static int hv_synic_suspend(void)
2579 {
2580         /*
2581          * When we reach here, all the non-boot CPUs have been offlined.
2582          * If we're in a legacy configuration where stimer Direct Mode is
2583          * not enabled, the stimers on the non-boot CPUs have been unbound
2584          * in hv_synic_cleanup() -> hv_stimer_legacy_cleanup() ->
2585          * hv_stimer_cleanup() -> clockevents_unbind_device().
2586          *
2587          * hv_synic_suspend() only runs on CPU0 with interrupts disabled.
2588          * Here we do not call hv_stimer_legacy_cleanup() on CPU0 because:
2589          * 1) it's unnecessary as interrupts remain disabled between
2590          * syscore_suspend() and syscore_resume(): see create_image() and
2591          * resume_target_kernel()
2592          * 2) the stimer on CPU0 is automatically disabled later by
2593          * syscore_suspend() -> timekeeping_suspend() -> tick_suspend() -> ...
2594          * -> clockevents_shutdown() -> ... -> hv_ce_shutdown()
2595          * 3) a warning would be triggered if we call
2596          * clockevents_unbind_device(), which may sleep, in an
2597          * interrupts-disabled context.
2598          */
2599
2600         hv_synic_disable_regs(0);
2601
2602         return 0;
2603 }
2604
2605 static void hv_synic_resume(void)
2606 {
2607         hv_synic_enable_regs(0);
2608
2609         /*
2610          * Note: we don't need to call hv_stimer_init(0), because the timer
2611          * on CPU0 is not unbound in hv_synic_suspend(), and the timer is
2612          * automatically re-enabled in timekeeping_resume().
2613          */
2614 }
2615
2616 /* The callbacks run only on CPU0, with irqs_disabled. */
2617 static struct syscore_ops hv_synic_syscore_ops = {
2618         .suspend = hv_synic_suspend,
2619         .resume = hv_synic_resume,
2620 };
2621
2622 static int __init hv_acpi_init(void)
2623 {
2624         int ret;
2625
2626         if (!hv_is_hyperv_initialized())
2627                 return -ENODEV;
2628
2629         if (hv_root_partition && !hv_nested)
2630                 return 0;
2631
2632         /*
2633          * Get ACPI resources first.
2634          */
2635         ret = platform_driver_register(&vmbus_platform_driver);
2636         if (ret)
2637                 return ret;
2638
2639         if (!hv_dev) {
2640                 ret = -ENODEV;
2641                 goto cleanup;
2642         }
2643
2644         /*
2645          * If we're on an architecture with a hardcoded hypervisor
2646          * vector (i.e. x86/x64), override the VMbus interrupt found
2647          * in the ACPI tables. Ensure vmbus_irq is not set since the
2648          * normal Linux IRQ mechanism is not used in this case.
2649          */
2650 #ifdef HYPERVISOR_CALLBACK_VECTOR
2651         vmbus_interrupt = HYPERVISOR_CALLBACK_VECTOR;
2652         vmbus_irq = -1;
2653 #endif
2654
2655         hv_debug_init();
2656
2657         ret = vmbus_bus_init();
2658         if (ret)
2659                 goto cleanup;
2660
2661         hv_setup_kexec_handler(hv_kexec_handler);
2662         hv_setup_crash_handler(hv_crash_handler);
2663
2664         register_syscore_ops(&hv_synic_syscore_ops);
2665
2666         return 0;
2667
2668 cleanup:
2669         platform_driver_unregister(&vmbus_platform_driver);
2670         hv_dev = NULL;
2671         return ret;
2672 }
2673
2674 static void __exit vmbus_exit(void)
2675 {
2676         int cpu;
2677
2678         unregister_syscore_ops(&hv_synic_syscore_ops);
2679
2680         hv_remove_kexec_handler();
2681         hv_remove_crash_handler();
2682         vmbus_connection.conn_state = DISCONNECTED;
2683         hv_stimer_global_cleanup();
2684         vmbus_disconnect();
2685         if (vmbus_irq == -1) {
2686                 hv_remove_vmbus_handler();
2687         } else {
2688                 free_percpu_irq(vmbus_irq, vmbus_evt);
2689                 free_percpu(vmbus_evt);
2690         }
2691         for_each_online_cpu(cpu) {
2692                 struct hv_per_cpu_context *hv_cpu
2693                         = per_cpu_ptr(hv_context.cpu_context, cpu);
2694
2695                 tasklet_kill(&hv_cpu->msg_dpc);
2696         }
2697         hv_debug_rm_all_dir();
2698
2699         vmbus_free_channels();
2700         kfree(vmbus_connection.channels);
2701
2702         /*
2703          * The vmbus panic notifier is always registered, hence we should
2704          * also unconditionally unregister it here as well.
2705          */
2706         atomic_notifier_chain_unregister(&panic_notifier_list,
2707                                         &hyperv_panic_vmbus_unload_block);
2708
2709         bus_unregister(&hv_bus);
2710
2711         cpuhp_remove_state(hyperv_cpuhp_online);
2712         hv_synic_free();
2713         platform_driver_unregister(&vmbus_platform_driver);
2714 }
2715
2716
2717 MODULE_LICENSE("GPL");
2718 MODULE_DESCRIPTION("Microsoft Hyper-V VMBus Driver");
2719
2720 subsys_initcall(hv_acpi_init);
2721 module_exit(vmbus_exit);