drivers/hv/vmbus_drv.c

   1 /*
   2  * Copyright (c) 2009, Microsoft Corporation.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms and conditions of the GNU General Public License,
   6  * version 2, as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  15  * Place - Suite 330, Boston, MA 02111-1307 USA.
  16  *
  17  * Authors:
  18  *   Haiyang Zhang <haiyangz@microsoft.com>
  19  *   Hank Janssen  <hjanssen@microsoft.com>
  20  *   K. Y. Srinivasan <kys@microsoft.com>
  21  *
  22  */
  23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  24
  25 #include <linux/init.h>
  26 #include <linux/module.h>
  27 #include <linux/device.h>
  28 #include <linux/interrupt.h>
  29 #include <linux/sysctl.h>
  30 #include <linux/slab.h>
  31 #include <linux/acpi.h>
  32 #include <linux/completion.h>
  33 #include <linux/hyperv.h>
  34 #include <linux/kernel_stat.h>
  35 #include <linux/clockchips.h>
  36 #include <linux/cpu.h>
  37 #include <asm/hyperv.h>
  38 #include <asm/hypervisor.h>
  39 #include <asm/mshyperv.h>
  40 #include <linux/notifier.h>
  41 #include <linux/ptrace.h>
  42 #include <linux/screen_info.h>
  43 #include <linux/kdebug.h>
  44 #include "hyperv_vmbus.h"
  45
  46 static struct acpi_device  *hv_acpi_dev;
  47
  48 static struct tasklet_struct msg_dpc;
  49 static struct completion probe_event;
  50
  51
  52 static void hyperv_report_panic(struct pt_regs *regs)
  53 {
  54         static bool panic_reported;
  55
  56         /*
  57          * We prefer to report panic on 'die' chain as we have proper
  58          * registers to report, but if we miss it (e.g. on BUG()) we need
  59          * to report it on 'panic'.
  60          */
  61         if (panic_reported)
  62                 return;
  63         panic_reported = true;
  64
  65         wrmsrl(HV_X64_MSR_CRASH_P0, regs->ip);
  66         wrmsrl(HV_X64_MSR_CRASH_P1, regs->ax);
  67         wrmsrl(HV_X64_MSR_CRASH_P2, regs->bx);
  68         wrmsrl(HV_X64_MSR_CRASH_P3, regs->cx);
  69         wrmsrl(HV_X64_MSR_CRASH_P4, regs->dx);
  70
  71         /*
  72          * Let Hyper-V know there is crash data available
  73          */
  74         wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
  75 }
  76
  77 static int hyperv_panic_event(struct notifier_block *nb, unsigned long val,
  78                               void *args)
  79 {
  80         struct pt_regs *regs;
  81
  82         regs = current_pt_regs();
  83
  84         hyperv_report_panic(regs);
  85         return NOTIFY_DONE;
  86 }
  87
  88 static int hyperv_die_event(struct notifier_block *nb, unsigned long val,
  89                             void *args)
  90 {
  91         struct die_args *die = (struct die_args *)args;
  92         struct pt_regs *regs = die->regs;
  93
  94         hyperv_report_panic(regs);
  95         return NOTIFY_DONE;
  96 }
  97
  98 static struct notifier_block hyperv_die_block = {
  99         .notifier_call = hyperv_die_event,
 100 };
 101 static struct notifier_block hyperv_panic_block = {
 102         .notifier_call = hyperv_panic_event,
 103 };
 104
 105 struct resource *hyperv_mmio;
 106
 107 static int vmbus_exists(void)
 108 {
 109         if (hv_acpi_dev == NULL)
 110                 return -ENODEV;
 111
 112         return 0;
 113 }
 114
 115 #define VMBUS_ALIAS_LEN ((sizeof((struct hv_vmbus_device_id *)0)->guid) * 2)
 116 static void print_alias_name(struct hv_device *hv_dev, char *alias_name)
 117 {
 118         int i;
 119         for (i = 0; i < VMBUS_ALIAS_LEN; i += 2)
 120                 sprintf(&alias_name[i], "%02x", hv_dev->dev_type.b[i/2]);
 121 }
 122
 123 static u8 channel_monitor_group(struct vmbus_channel *channel)
 124 {
 125         return (u8)channel->offermsg.monitorid / 32;
 126 }
 127
 128 static u8 channel_monitor_offset(struct vmbus_channel *channel)
 129 {
 130         return (u8)channel->offermsg.monitorid % 32;
 131 }
 132
 133 static u32 channel_pending(struct vmbus_channel *channel,
 134                            struct hv_monitor_page *monitor_page)
 135 {
 136         u8 monitor_group = channel_monitor_group(channel);
 137         return monitor_page->trigger_group[monitor_group].pending;
 138 }
 139
 140 static u32 channel_latency(struct vmbus_channel *channel,
 141                            struct hv_monitor_page *monitor_page)
 142 {
 143         u8 monitor_group = channel_monitor_group(channel);
 144         u8 monitor_offset = channel_monitor_offset(channel);
 145         return monitor_page->latency[monitor_group][monitor_offset];
 146 }
 147
 148 static u32 channel_conn_id(struct vmbus_channel *channel,
 149                            struct hv_monitor_page *monitor_page)
 150 {
 151         u8 monitor_group = channel_monitor_group(channel);
 152         u8 monitor_offset = channel_monitor_offset(channel);
 153         return monitor_page->parameter[monitor_group][monitor_offset].connectionid.u.id;
 154 }
 155
 156 static ssize_t id_show(struct device *dev, struct device_attribute *dev_attr,
 157                        char *buf)
 158 {
 159         struct hv_device *hv_dev = device_to_hv_device(dev);
 160
 161         if (!hv_dev->channel)
 162                 return -ENODEV;
 163         return sprintf(buf, "%d\n", hv_dev->channel->offermsg.child_relid);
 164 }
 165 static DEVICE_ATTR_RO(id);
 166
 167 static ssize_t state_show(struct device *dev, struct device_attribute *dev_attr,
 168                           char *buf)
 169 {
 170         struct hv_device *hv_dev = device_to_hv_device(dev);
 171
 172         if (!hv_dev->channel)
 173                 return -ENODEV;
 174         return sprintf(buf, "%d\n", hv_dev->channel->state);
 175 }
 176 static DEVICE_ATTR_RO(state);
 177
 178 static ssize_t monitor_id_show(struct device *dev,
 179                                struct device_attribute *dev_attr, char *buf)
 180 {
 181         struct hv_device *hv_dev = device_to_hv_device(dev);
 182
 183         if (!hv_dev->channel)
 184                 return -ENODEV;
 185         return sprintf(buf, "%d\n", hv_dev->channel->offermsg.monitorid);
 186 }
 187 static DEVICE_ATTR_RO(monitor_id);
 188
 189 static ssize_t class_id_show(struct device *dev,
 190                                struct device_attribute *dev_attr, char *buf)
 191 {
 192         struct hv_device *hv_dev = device_to_hv_device(dev);
 193
 194         if (!hv_dev->channel)
 195                 return -ENODEV;
 196         return sprintf(buf, "{%pUl}\n",
 197                        hv_dev->channel->offermsg.offer.if_type.b);
 198 }
 199 static DEVICE_ATTR_RO(class_id);
 200
 201 static ssize_t device_id_show(struct device *dev,
 202                               struct device_attribute *dev_attr, char *buf)
 203 {
 204         struct hv_device *hv_dev = device_to_hv_device(dev);
 205
 206         if (!hv_dev->channel)
 207                 return -ENODEV;
 208         return sprintf(buf, "{%pUl}\n",
 209                        hv_dev->channel->offermsg.offer.if_instance.b);
 210 }
 211 static DEVICE_ATTR_RO(device_id);
 212
 213 static ssize_t modalias_show(struct device *dev,
 214                              struct device_attribute *dev_attr, char *buf)
 215 {
 216         struct hv_device *hv_dev = device_to_hv_device(dev);
 217         char alias_name[VMBUS_ALIAS_LEN + 1];
 218
 219         print_alias_name(hv_dev, alias_name);
 220         return sprintf(buf, "vmbus:%s\n", alias_name);
 221 }
 222 static DEVICE_ATTR_RO(modalias);
 223
 224 static ssize_t server_monitor_pending_show(struct device *dev,
 225                                            struct device_attribute *dev_attr,
 226                                            char *buf)
 227 {
 228         struct hv_device *hv_dev = device_to_hv_device(dev);
 229
 230         if (!hv_dev->channel)
 231                 return -ENODEV;
 232         return sprintf(buf, "%d\n",
 233                        channel_pending(hv_dev->channel,
 234                                        vmbus_connection.monitor_pages[1]));
 235 }
 236 static DEVICE_ATTR_RO(server_monitor_pending);
 237
 238 static ssize_t client_monitor_pending_show(struct device *dev,
 239                                            struct device_attribute *dev_attr,
 240                                            char *buf)
 241 {
 242         struct hv_device *hv_dev = device_to_hv_device(dev);
 243
 244         if (!hv_dev->channel)
 245                 return -ENODEV;
 246         return sprintf(buf, "%d\n",
 247                        channel_pending(hv_dev->channel,
 248                                        vmbus_connection.monitor_pages[1]));
 249 }
 250 static DEVICE_ATTR_RO(client_monitor_pending);
 251
 252 static ssize_t server_monitor_latency_show(struct device *dev,
 253                                            struct device_attribute *dev_attr,
 254                                            char *buf)
 255 {
 256         struct hv_device *hv_dev = device_to_hv_device(dev);
 257
 258         if (!hv_dev->channel)
 259                 return -ENODEV;
 260         return sprintf(buf, "%d\n",
 261                        channel_latency(hv_dev->channel,
 262                                        vmbus_connection.monitor_pages[0]));
 263 }
 264 static DEVICE_ATTR_RO(server_monitor_latency);
 265
 266 static ssize_t client_monitor_latency_show(struct device *dev,
 267                                            struct device_attribute *dev_attr,
 268                                            char *buf)
 269 {
 270         struct hv_device *hv_dev = device_to_hv_device(dev);
 271
 272         if (!hv_dev->channel)
 273                 return -ENODEV;
 274         return sprintf(buf, "%d\n",
 275                        channel_latency(hv_dev->channel,
 276                                        vmbus_connection.monitor_pages[1]));
 277 }
 278 static DEVICE_ATTR_RO(client_monitor_latency);
 279
 280 static ssize_t server_monitor_conn_id_show(struct device *dev,
 281                                            struct device_attribute *dev_attr,
 282                                            char *buf)
 283 {
 284         struct hv_device *hv_dev = device_to_hv_device(dev);
 285
 286         if (!hv_dev->channel)
 287                 return -ENODEV;
 288         return sprintf(buf, "%d\n",
 289                        channel_conn_id(hv_dev->channel,
 290                                        vmbus_connection.monitor_pages[0]));
 291 }
 292 static DEVICE_ATTR_RO(server_monitor_conn_id);
 293
 294 static ssize_t client_monitor_conn_id_show(struct device *dev,
 295                                            struct device_attribute *dev_attr,
 296                                            char *buf)
 297 {
 298         struct hv_device *hv_dev = device_to_hv_device(dev);
 299
 300         if (!hv_dev->channel)
 301                 return -ENODEV;
 302         return sprintf(buf, "%d\n",
 303                        channel_conn_id(hv_dev->channel,
 304                                        vmbus_connection.monitor_pages[1]));
 305 }
 306 static DEVICE_ATTR_RO(client_monitor_conn_id);
 307
 308 static ssize_t out_intr_mask_show(struct device *dev,
 309                                   struct device_attribute *dev_attr, char *buf)
 310 {
 311         struct hv_device *hv_dev = device_to_hv_device(dev);
 312         struct hv_ring_buffer_debug_info outbound;
 313
 314         if (!hv_dev->channel)
 315                 return -ENODEV;
 316         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 317         return sprintf(buf, "%d\n", outbound.current_interrupt_mask);
 318 }
 319 static DEVICE_ATTR_RO(out_intr_mask);
 320
 321 static ssize_t out_read_index_show(struct device *dev,
 322                                    struct device_attribute *dev_attr, char *buf)
 323 {
 324         struct hv_device *hv_dev = device_to_hv_device(dev);
 325         struct hv_ring_buffer_debug_info outbound;
 326
 327         if (!hv_dev->channel)
 328                 return -ENODEV;
 329         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 330         return sprintf(buf, "%d\n", outbound.current_read_index);
 331 }
 332 static DEVICE_ATTR_RO(out_read_index);
 333
 334 static ssize_t out_write_index_show(struct device *dev,
 335                                     struct device_attribute *dev_attr,
 336                                     char *buf)
 337 {
 338         struct hv_device *hv_dev = device_to_hv_device(dev);
 339         struct hv_ring_buffer_debug_info outbound;
 340
 341         if (!hv_dev->channel)
 342                 return -ENODEV;
 343         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 344         return sprintf(buf, "%d\n", outbound.current_write_index);
 345 }
 346 static DEVICE_ATTR_RO(out_write_index);
 347
 348 static ssize_t out_read_bytes_avail_show(struct device *dev,
 349                                          struct device_attribute *dev_attr,
 350                                          char *buf)
 351 {
 352         struct hv_device *hv_dev = device_to_hv_device(dev);
 353         struct hv_ring_buffer_debug_info outbound;
 354
 355         if (!hv_dev->channel)
 356                 return -ENODEV;
 357         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 358         return sprintf(buf, "%d\n", outbound.bytes_avail_toread);
 359 }
 360 static DEVICE_ATTR_RO(out_read_bytes_avail);
 361
 362 static ssize_t out_write_bytes_avail_show(struct device *dev,
 363                                           struct device_attribute *dev_attr,
 364                                           char *buf)
 365 {
 366         struct hv_device *hv_dev = device_to_hv_device(dev);
 367         struct hv_ring_buffer_debug_info outbound;
 368
 369         if (!hv_dev->channel)
 370                 return -ENODEV;
 371         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 372         return sprintf(buf, "%d\n", outbound.bytes_avail_towrite);
 373 }
 374 static DEVICE_ATTR_RO(out_write_bytes_avail);
 375
 376 static ssize_t in_intr_mask_show(struct device *dev,
 377                                  struct device_attribute *dev_attr, char *buf)
 378 {
 379         struct hv_device *hv_dev = device_to_hv_device(dev);
 380         struct hv_ring_buffer_debug_info inbound;
 381
 382         if (!hv_dev->channel)
 383                 return -ENODEV;
 384         hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 385         return sprintf(buf, "%d\n", inbound.current_interrupt_mask);
 386 }
 387 static DEVICE_ATTR_RO(in_intr_mask);
 388
 389 static ssize_t in_read_index_show(struct device *dev,
 390                                   struct device_attribute *dev_attr, char *buf)
 391 {
 392         struct hv_device *hv_dev = device_to_hv_device(dev);
 393         struct hv_ring_buffer_debug_info inbound;
 394
 395         if (!hv_dev->channel)
 396                 return -ENODEV;
 397         hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 398         return sprintf(buf, "%d\n", inbound.current_read_index);
 399 }
 400 static DEVICE_ATTR_RO(in_read_index);
 401
 402 static ssize_t in_write_index_show(struct device *dev,
 403                                    struct device_attribute *dev_attr, char *buf)
 404 {
 405         struct hv_device *hv_dev = device_to_hv_device(dev);
 406         struct hv_ring_buffer_debug_info inbound;
 407
 408         if (!hv_dev->channel)
 409                 return -ENODEV;
 410         hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 411         return sprintf(buf, "%d\n", inbound.current_write_index);
 412 }
 413 static DEVICE_ATTR_RO(in_write_index);
 414
 415 static ssize_t in_read_bytes_avail_show(struct device *dev,
 416                                         struct device_attribute *dev_attr,
 417                                         char *buf)
 418 {
 419         struct hv_device *hv_dev = device_to_hv_device(dev);
 420         struct hv_ring_buffer_debug_info inbound;
 421
 422         if (!hv_dev->channel)
 423                 return -ENODEV;
 424         hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 425         return sprintf(buf, "%d\n", inbound.bytes_avail_toread);
 426 }
 427 static DEVICE_ATTR_RO(in_read_bytes_avail);
 428
 429 static ssize_t in_write_bytes_avail_show(struct device *dev,
 430                                          struct device_attribute *dev_attr,
 431                                          char *buf)
 432 {
 433         struct hv_device *hv_dev = device_to_hv_device(dev);
 434         struct hv_ring_buffer_debug_info inbound;
 435
 436         if (!hv_dev->channel)
 437                 return -ENODEV;
 438         hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 439         return sprintf(buf, "%d\n", inbound.bytes_avail_towrite);
 440 }
 441 static DEVICE_ATTR_RO(in_write_bytes_avail);
 442
 443 static ssize_t channel_vp_mapping_show(struct device *dev,
 444                                        struct device_attribute *dev_attr,
 445                                        char *buf)
 446 {
 447         struct hv_device *hv_dev = device_to_hv_device(dev);
 448         struct vmbus_channel *channel = hv_dev->channel, *cur_sc;
 449         unsigned long flags;
 450         int buf_size = PAGE_SIZE, n_written, tot_written;
 451         struct list_head *cur;
 452
 453         if (!channel)
 454                 return -ENODEV;
 455
 456         tot_written = snprintf(buf, buf_size, "%u:%u\n",
 457                 channel->offermsg.child_relid, channel->target_cpu);
 458
 459         spin_lock_irqsave(&channel->lock, flags);
 460
 461         list_for_each(cur, &channel->sc_list) {
 462                 if (tot_written >= buf_size - 1)
 463                         break;
 464
 465                 cur_sc = list_entry(cur, struct vmbus_channel, sc_list);
 466                 n_written = scnprintf(buf + tot_written,
 467                                      buf_size - tot_written,
 468                                      "%u:%u\n",
 469                                      cur_sc->offermsg.child_relid,
 470                                      cur_sc->target_cpu);
 471                 tot_written += n_written;
 472         }
 473
 474         spin_unlock_irqrestore(&channel->lock, flags);
 475
 476         return tot_written;
 477 }
 478 static DEVICE_ATTR_RO(channel_vp_mapping);
 479
 480 /* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
 481 static struct attribute *vmbus_attrs[] = {
 482         &dev_attr_id.attr,
 483         &dev_attr_state.attr,
 484         &dev_attr_monitor_id.attr,
 485         &dev_attr_class_id.attr,
 486         &dev_attr_device_id.attr,
 487         &dev_attr_modalias.attr,
 488         &dev_attr_server_monitor_pending.attr,
 489         &dev_attr_client_monitor_pending.attr,
 490         &dev_attr_server_monitor_latency.attr,
 491         &dev_attr_client_monitor_latency.attr,
 492         &dev_attr_server_monitor_conn_id.attr,
 493         &dev_attr_client_monitor_conn_id.attr,
 494         &dev_attr_out_intr_mask.attr,
 495         &dev_attr_out_read_index.attr,
 496         &dev_attr_out_write_index.attr,
 497         &dev_attr_out_read_bytes_avail.attr,
 498         &dev_attr_out_write_bytes_avail.attr,
 499         &dev_attr_in_intr_mask.attr,
 500         &dev_attr_in_read_index.attr,
 501         &dev_attr_in_write_index.attr,
 502         &dev_attr_in_read_bytes_avail.attr,
 503         &dev_attr_in_write_bytes_avail.attr,
 504         &dev_attr_channel_vp_mapping.attr,
 505         NULL,
 506 };
 507 ATTRIBUTE_GROUPS(vmbus);
 508
 509 /*
 510  * vmbus_uevent - add uevent for our device
 511  *
 512  * This routine is invoked when a device is added or removed on the vmbus to
 513  * generate a uevent to udev in the userspace. The udev will then look at its
 514  * rule and the uevent generated here to load the appropriate driver
 515  *
 516  * The alias string will be of the form vmbus:guid where guid is the string
 517  * representation of the device guid (each byte of the guid will be
 518  * represented with two hex characters.
 519  */
 520 static int vmbus_uevent(struct device *device, struct kobj_uevent_env *env)
 521 {
 522         struct hv_device *dev = device_to_hv_device(device);
 523         int ret;
 524         char alias_name[VMBUS_ALIAS_LEN + 1];
 525
 526         print_alias_name(dev, alias_name);
 527         ret = add_uevent_var(env, "MODALIAS=vmbus:%s", alias_name);
 528         return ret;
 529 }
 530
 531 static const uuid_le null_guid;
 532
 533 static inline bool is_null_guid(const uuid_le *guid)
 534 {
 535         if (uuid_le_cmp(*guid, null_guid))
 536                 return false;
 537         return true;
 538 }
 539
 540 /*
 541  * Return a matching hv_vmbus_device_id pointer.
 542  * If there is no match, return NULL.
 543  */
 544 static const struct hv_vmbus_device_id *hv_vmbus_get_id(
 545                                         const struct hv_vmbus_device_id *id,
 546                                         const uuid_le *guid)
 547 {
 548         for (; !is_null_guid(&id->guid); id++)
 549                 if (!uuid_le_cmp(id->guid, *guid))
 550                         return id;
 551
 552         return NULL;
 553 }
 554
 555
 556
 557 /*
 558  * vmbus_match - Attempt to match the specified device to the specified driver
 559  */
 560 static int vmbus_match(struct device *device, struct device_driver *driver)
 561 {
 562         struct hv_driver *drv = drv_to_hv_drv(driver);
 563         struct hv_device *hv_dev = device_to_hv_device(device);
 564
 565         if (hv_vmbus_get_id(drv->id_table, &hv_dev->dev_type))
 566                 return 1;
 567
 568         return 0;
 569 }
 570
 571 /*
 572  * vmbus_probe - Add the new vmbus's child device
 573  */
 574 static int vmbus_probe(struct device *child_device)
 575 {
 576         int ret = 0;
 577         struct hv_driver *drv =
 578                         drv_to_hv_drv(child_device->driver);
 579         struct hv_device *dev = device_to_hv_device(child_device);
 580         const struct hv_vmbus_device_id *dev_id;
 581
 582         dev_id = hv_vmbus_get_id(drv->id_table, &dev->dev_type);
 583         if (drv->probe) {
 584                 ret = drv->probe(dev, dev_id);
 585                 if (ret != 0)
 586                         pr_err("probe failed for device %s (%d)\n",
 587                                dev_name(child_device), ret);
 588
 589         } else {
 590                 pr_err("probe not set for driver %s\n",
 591                        dev_name(child_device));
 592                 ret = -ENODEV;
 593         }
 594         return ret;
 595 }
 596
 597 /*
 598  * vmbus_remove - Remove a vmbus device
 599  */
 600 static int vmbus_remove(struct device *child_device)
 601 {
 602         struct hv_driver *drv;
 603         struct hv_device *dev = device_to_hv_device(child_device);
 604
 605         if (child_device->driver) {
 606                 drv = drv_to_hv_drv(child_device->driver);
 607                 if (drv->remove)
 608                         drv->remove(dev);
 609         }
 610
 611         return 0;
 612 }
 613
 614
 615 /*
 616  * vmbus_shutdown - Shutdown a vmbus device
 617  */
 618 static void vmbus_shutdown(struct device *child_device)
 619 {
 620         struct hv_driver *drv;
 621         struct hv_device *dev = device_to_hv_device(child_device);
 622
 623
 624         /* The device may not be attached yet */
 625         if (!child_device->driver)
 626                 return;
 627
 628         drv = drv_to_hv_drv(child_device->driver);
 629
 630         if (drv->shutdown)
 631                 drv->shutdown(dev);
 632
 633         return;
 634 }
 635
 636
 637 /*
 638  * vmbus_device_release - Final callback release of the vmbus child device
 639  */
 640 static void vmbus_device_release(struct device *device)
 641 {
 642         struct hv_device *hv_dev = device_to_hv_device(device);
 643         struct vmbus_channel *channel = hv_dev->channel;
 644
 645         hv_process_channel_removal(channel,
 646                                    channel->offermsg.child_relid);
 647         kfree(hv_dev);
 648
 649 }
 650
 651 /* The one and only one */
 652 static struct bus_type  hv_bus = {
 653         .name =         "vmbus",
 654         .match =                vmbus_match,
 655         .shutdown =             vmbus_shutdown,
 656         .remove =               vmbus_remove,
 657         .probe =                vmbus_probe,
 658         .uevent =               vmbus_uevent,
 659         .dev_groups =           vmbus_groups,
 660 };
 661
 662 struct onmessage_work_context {
 663         struct work_struct work;
 664         struct hv_message msg;
 665 };
 666
 667 static void vmbus_onmessage_work(struct work_struct *work)
 668 {
 669         struct onmessage_work_context *ctx;
 670
 671         /* Do not process messages if we're in DISCONNECTED state */
 672         if (vmbus_connection.conn_state == DISCONNECTED)
 673                 return;
 674
 675         ctx = container_of(work, struct onmessage_work_context,
 676                            work);
 677         vmbus_onmessage(&ctx->msg);
 678         kfree(ctx);
 679 }
 680
 681 static void hv_process_timer_expiration(struct hv_message *msg, int cpu)
 682 {
 683         struct clock_event_device *dev = hv_context.clk_evt[cpu];
 684
 685         if (dev->event_handler)
 686                 dev->event_handler(dev);
 687
 688         msg->header.message_type = HVMSG_NONE;
 689
 690         /*
 691          * Make sure the write to MessageType (ie set to
 692          * HVMSG_NONE) happens before we read the
 693          * MessagePending and EOMing. Otherwise, the EOMing
 694          * will not deliver any more messages since there is
 695          * no empty slot
 696          */
 697         mb();
 698
 699         if (msg->header.message_flags.msg_pending) {
 700                 /*
 701                  * This will cause message queue rescan to
 702                  * possibly deliver another msg from the
 703                  * hypervisor
 704                  */
 705                 wrmsrl(HV_X64_MSR_EOM, 0);
 706         }
 707 }
 708
 709 static void vmbus_on_msg_dpc(unsigned long data)
 710 {
 711         int cpu = smp_processor_id();
 712         void *page_addr = hv_context.synic_message_page[cpu];
 713         struct hv_message *msg = (struct hv_message *)page_addr +
 714                                   VMBUS_MESSAGE_SINT;
 715         struct vmbus_channel_message_header *hdr;
 716         struct vmbus_channel_message_table_entry *entry;
 717         struct onmessage_work_context *ctx;
 718
 719         while (1) {
 720                 if (msg->header.message_type == HVMSG_NONE)
 721                         /* no msg */
 722                         break;
 723
 724                 hdr = (struct vmbus_channel_message_header *)msg->u.payload;
 725
 726                 if (hdr->msgtype >= CHANNELMSG_COUNT) {
 727                         WARN_ONCE(1, "unknown msgtype=%d\n", hdr->msgtype);
 728                         goto msg_handled;
 729                 }
 730
 731                 entry = &channel_message_table[hdr->msgtype];
 732                 if (entry->handler_type == VMHT_BLOCKING) {
 733                         ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC);
 734                         if (ctx == NULL)
 735                                 continue;
 736
 737                         INIT_WORK(&ctx->work, vmbus_onmessage_work);
 738                         memcpy(&ctx->msg, msg, sizeof(*msg));
 739
 740                         queue_work(vmbus_connection.work_queue, &ctx->work);
 741                 } else
 742                         entry->message_handler(hdr);
 743
 744 msg_handled:
 745                 msg->header.message_type = HVMSG_NONE;
 746
 747                 /*
 748                  * Make sure the write to MessageType (ie set to
 749                  * HVMSG_NONE) happens before we read the
 750                  * MessagePending and EOMing. Otherwise, the EOMing
 751                  * will not deliver any more messages since there is
 752                  * no empty slot
 753                  */
 754                 mb();
 755
 756                 if (msg->header.message_flags.msg_pending) {
 757                         /*
 758                          * This will cause message queue rescan to
 759                          * possibly deliver another msg from the
 760                          * hypervisor
 761                          */
 762                         wrmsrl(HV_X64_MSR_EOM, 0);
 763                 }
 764         }
 765 }
 766
 767 static void vmbus_isr(void)
 768 {
 769         int cpu = smp_processor_id();
 770         void *page_addr;
 771         struct hv_message *msg;
 772         union hv_synic_event_flags *event;
 773         bool handled = false;
 774
 775         page_addr = hv_context.synic_event_page[cpu];
 776         if (page_addr == NULL)
 777                 return;
 778
 779         event = (union hv_synic_event_flags *)page_addr +
 780                                          VMBUS_MESSAGE_SINT;
 781         /*
 782          * Check for events before checking for messages. This is the order
 783          * in which events and messages are checked in Windows guests on
 784          * Hyper-V, and the Windows team suggested we do the same.
 785          */
 786
 787         if ((vmbus_proto_version == VERSION_WS2008) ||
 788                 (vmbus_proto_version == VERSION_WIN7)) {
 789
 790                 /* Since we are a child, we only need to check bit 0 */
 791                 if (sync_test_and_clear_bit(0,
 792                         (unsigned long *) &event->flags32[0])) {
 793                         handled = true;
 794                 }
 795         } else {
 796                 /*
 797                  * Our host is win8 or above. The signaling mechanism
 798                  * has changed and we can directly look at the event page.
 799                  * If bit n is set then we have an interrup on the channel
 800                  * whose id is n.
 801                  */
 802                 handled = true;
 803         }
 804
 805         if (handled)
 806                 tasklet_schedule(hv_context.event_dpc[cpu]);
 807
 808
 809         page_addr = hv_context.synic_message_page[cpu];
 810         msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
 811
 812         /* Check if there are actual msgs to be processed */
 813         if (msg->header.message_type != HVMSG_NONE) {
 814                 if (msg->header.message_type == HVMSG_TIMER_EXPIRED)
 815                         hv_process_timer_expiration(msg, cpu);
 816                 else
 817                         tasklet_schedule(&msg_dpc);
 818         }
 819 }
 820
 821
 822 /*
 823  * vmbus_bus_init -Main vmbus driver initialization routine.
 824  *
 825  * Here, we
 826  *      - initialize the vmbus driver context
 827  *      - invoke the vmbus hv main init routine
 828  *      - retrieve the channel offers
 829  */
 830 static int vmbus_bus_init(void)
 831 {
 832         int ret;
 833
 834         /* Hypervisor initialization...setup hypercall page..etc */
 835         ret = hv_init();
 836         if (ret != 0) {
 837                 pr_err("Unable to initialize the hypervisor - 0x%x\n", ret);
 838                 return ret;
 839         }
 840
 841         tasklet_init(&msg_dpc, vmbus_on_msg_dpc, 0);
 842
 843         ret = bus_register(&hv_bus);
 844         if (ret)
 845                 goto err_cleanup;
 846
 847         hv_setup_vmbus_irq(vmbus_isr);
 848
 849         ret = hv_synic_alloc();
 850         if (ret)
 851                 goto err_alloc;
 852         /*
 853          * Initialize the per-cpu interrupt state and
 854          * connect to the host.
 855          */
 856         on_each_cpu(hv_synic_init, NULL, 1);
 857         ret = vmbus_connect();
 858         if (ret)
 859                 goto err_connect;
 860
 861         if (vmbus_proto_version > VERSION_WIN7)
 862                 cpu_hotplug_disable();
 863
 864         /*
 865          * Only register if the crash MSRs are available
 866          */
 867         if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
 868                 register_die_notifier(&hyperv_die_block);
 869                 atomic_notifier_chain_register(&panic_notifier_list,
 870                                                &hyperv_panic_block);
 871         }
 872
 873         vmbus_request_offers();
 874
 875         return 0;
 876
 877 err_connect:
 878         on_each_cpu(hv_synic_cleanup, NULL, 1);
 879 err_alloc:
 880         hv_synic_free();
 881         hv_remove_vmbus_irq();
 882
 883         bus_unregister(&hv_bus);
 884
 885 err_cleanup:
 886         hv_cleanup();
 887
 888         return ret;
 889 }
 890
 891 /**
 892  * __vmbus_child_driver_register() - Register a vmbus's driver
 893  * @hv_driver: Pointer to driver structure you want to register
 894  * @owner: owner module of the drv
 895  * @mod_name: module name string
 896  *
 897  * Registers the given driver with Linux through the 'driver_register()' call
 898  * and sets up the hyper-v vmbus handling for this driver.
 899  * It will return the state of the 'driver_register()' call.
 900  *
 901  */
 902 int __vmbus_driver_register(struct hv_driver *hv_driver, struct module *owner, const char *mod_name)
 903 {
 904         int ret;
 905
 906         pr_info("registering driver %s\n", hv_driver->name);
 907
 908         ret = vmbus_exists();
 909         if (ret < 0)
 910                 return ret;
 911
 912         hv_driver->driver.name = hv_driver->name;
 913         hv_driver->driver.owner = owner;
 914         hv_driver->driver.mod_name = mod_name;
 915         hv_driver->driver.bus = &hv_bus;
 916
 917         ret = driver_register(&hv_driver->driver);
 918
 919         return ret;
 920 }
 921 EXPORT_SYMBOL_GPL(__vmbus_driver_register);
 922
 923 /**
 924  * vmbus_driver_unregister() - Unregister a vmbus's driver
 925  * @hv_driver: Pointer to driver structure you want to
 926  *             un-register
 927  *
 928  * Un-register the given driver that was previous registered with a call to
 929  * vmbus_driver_register()
 930  */
 931 void vmbus_driver_unregister(struct hv_driver *hv_driver)
 932 {
 933         pr_info("unregistering driver %s\n", hv_driver->name);
 934
 935         if (!vmbus_exists())
 936                 driver_unregister(&hv_driver->driver);
 937 }
 938 EXPORT_SYMBOL_GPL(vmbus_driver_unregister);
 939
 940 /*
 941  * vmbus_device_create - Creates and registers a new child device
 942  * on the vmbus.
 943  */
 944 struct hv_device *vmbus_device_create(const uuid_le *type,
 945                                       const uuid_le *instance,
 946                                       struct vmbus_channel *channel)
 947 {
 948         struct hv_device *child_device_obj;
 949
 950         child_device_obj = kzalloc(sizeof(struct hv_device), GFP_KERNEL);
 951         if (!child_device_obj) {
 952                 pr_err("Unable to allocate device object for child device\n");
 953                 return NULL;
 954         }
 955
 956         child_device_obj->channel = channel;
 957         memcpy(&child_device_obj->dev_type, type, sizeof(uuid_le));
 958         memcpy(&child_device_obj->dev_instance, instance,
 959                sizeof(uuid_le));
 960
 961
 962         return child_device_obj;
 963 }
 964
 965 /*
 966  * vmbus_device_register - Register the child device
 967  */
 968 int vmbus_device_register(struct hv_device *child_device_obj)
 969 {
 970         int ret = 0;
 971
 972         dev_set_name(&child_device_obj->device, "vmbus_%d",
 973                      child_device_obj->channel->id);
 974
 975         child_device_obj->device.bus = &hv_bus;
 976         child_device_obj->device.parent = &hv_acpi_dev->dev;
 977         child_device_obj->device.release = vmbus_device_release;
 978
 979         /*
 980          * Register with the LDM. This will kick off the driver/device
 981          * binding...which will eventually call vmbus_match() and vmbus_probe()
 982          */
 983         ret = device_register(&child_device_obj->device);
 984
 985         if (ret)
 986                 pr_err("Unable to register child device\n");
 987         else
 988                 pr_debug("child device %s registered\n",
 989                         dev_name(&child_device_obj->device));
 990
 991         return ret;
 992 }
 993
 994 /*
 995  * vmbus_device_unregister - Remove the specified child device
 996  * from the vmbus.
 997  */
 998 void vmbus_device_unregister(struct hv_device *device_obj)
 999 {
1000         pr_debug("child device %s unregistered\n",
1001                 dev_name(&device_obj->device));
1002
1003         /*
1004          * Kick off the process of unregistering the device.
1005          * This will call vmbus_remove() and eventually vmbus_device_release()
1006          */
1007         device_unregister(&device_obj->device);
1008 }
1009
1010
1011 /*
1012  * VMBUS is an acpi enumerated device. Get the information we
1013  * need from DSDT.
1014  */
1015 #define VTPM_BASE_ADDRESS 0xfed40000
1016 static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *ctx)
1017 {
1018         resource_size_t start = 0;
1019         resource_size_t end = 0;
1020         struct resource *new_res;
1021         struct resource **old_res = &hyperv_mmio;
1022         struct resource **prev_res = NULL;
1023
1024         switch (res->type) {
1025
1026         /*
1027          * "Address" descriptors are for bus windows. Ignore
1028          * "memory" descriptors, which are for registers on
1029          * devices.
1030          */
1031         case ACPI_RESOURCE_TYPE_ADDRESS32:
1032                 start = res->data.address32.address.minimum;
1033                 end = res->data.address32.address.maximum;
1034                 break;
1035
1036         case ACPI_RESOURCE_TYPE_ADDRESS64:
1037                 start = res->data.address64.address.minimum;
1038                 end = res->data.address64.address.maximum;
1039                 break;
1040
1041         default:
1042                 /* Unused resource type */
1043                 return AE_OK;
1044
1045         }
1046         /*
1047          * Ignore ranges that are below 1MB, as they're not
1048          * necessary or useful here.
1049          */
1050         if (end < 0x100000)
1051                 return AE_OK;
1052
1053         new_res = kzalloc(sizeof(*new_res), GFP_ATOMIC);
1054         if (!new_res)
1055                 return AE_NO_MEMORY;
1056
1057         /* If this range overlaps the virtual TPM, truncate it. */
1058         if (end > VTPM_BASE_ADDRESS && start < VTPM_BASE_ADDRESS)
1059                 end = VTPM_BASE_ADDRESS;
1060
1061         new_res->name = "hyperv mmio";
1062         new_res->flags = IORESOURCE_MEM;
1063         new_res->start = start;
1064         new_res->end = end;
1065
1066         /*
1067          * Stick ranges from higher in address space at the front of the list.
1068          * If two ranges are adjacent, merge them.
1069          */
1070         do {
1071                 if (!*old_res) {
1072                         *old_res = new_res;
1073                         break;
1074                 }
1075
1076                 if (((*old_res)->end + 1) == new_res->start) {
1077                         (*old_res)->end = new_res->end;
1078                         kfree(new_res);
1079                         break;
1080                 }
1081
1082                 if ((*old_res)->start == new_res->end + 1) {
1083                         (*old_res)->start = new_res->start;
1084                         kfree(new_res);
1085                         break;
1086                 }
1087
1088                 if ((*old_res)->end < new_res->start) {
1089                         new_res->sibling = *old_res;
1090                         if (prev_res)
1091                                 (*prev_res)->sibling = new_res;
1092                         *old_res = new_res;
1093                         break;
1094                 }
1095
1096                 prev_res = old_res;
1097                 old_res = &(*old_res)->sibling;
1098
1099         } while (1);
1100
1101         return AE_OK;
1102 }
1103
1104 static int vmbus_acpi_remove(struct acpi_device *device)
1105 {
1106         struct resource *cur_res;
1107         struct resource *next_res;
1108
1109         if (hyperv_mmio) {
1110                 for (cur_res = hyperv_mmio; cur_res; cur_res = next_res) {
1111                         next_res = cur_res->sibling;
1112                         kfree(cur_res);
1113                 }
1114         }
1115
1116         return 0;
1117 }
1118
1119 /**
1120  * vmbus_allocate_mmio() - Pick a memory-mapped I/O range.
1121  * @new:                If successful, supplied a pointer to the
1122  *                      allocated MMIO space.
1123  * @device_obj:         Identifies the caller
1124  * @min:                Minimum guest physical address of the
1125  *                      allocation
1126  * @max:                Maximum guest physical address
1127  * @size:               Size of the range to be allocated
1128  * @align:              Alignment of the range to be allocated
1129  * @fb_overlap_ok:      Whether this allocation can be allowed
1130  *                      to overlap the video frame buffer.
1131  *
1132  * This function walks the resources granted to VMBus by the
1133  * _CRS object in the ACPI namespace underneath the parent
1134  * "bridge" whether that's a root PCI bus in the Generation 1
1135  * case or a Module Device in the Generation 2 case.  It then
1136  * attempts to allocate from the global MMIO pool in a way that
1137  * matches the constraints supplied in these parameters and by
1138  * that _CRS.
1139  *
1140  * Return: 0 on success, -errno on failure
1141  */
1142 int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
1143                         resource_size_t min, resource_size_t max,
1144                         resource_size_t size, resource_size_t align,
1145                         bool fb_overlap_ok)
1146 {
1147         struct resource *iter;
1148         resource_size_t range_min, range_max, start, local_min, local_max;
1149         const char *dev_n = dev_name(&device_obj->device);
1150         u32 fb_end = screen_info.lfb_base + (screen_info.lfb_size << 1);
1151         int i;
1152
1153         for (iter = hyperv_mmio; iter; iter = iter->sibling) {
1154                 if ((iter->start >= max) || (iter->end <= min))
1155                         continue;
1156
1157                 range_min = iter->start;
1158                 range_max = iter->end;
1159
1160                 /* If this range overlaps the frame buffer, split it into
1161                    two tries. */
1162                 for (i = 0; i < 2; i++) {
1163                         local_min = range_min;
1164                         local_max = range_max;
1165                         if (fb_overlap_ok || (range_min >= fb_end) ||
1166                             (range_max <= screen_info.lfb_base)) {
1167                                 i++;
1168                         } else {
1169                                 if ((range_min <= screen_info.lfb_base) &&
1170                                     (range_max >= screen_info.lfb_base)) {
1171                                         /*
1172                                          * The frame buffer is in this window,
1173                                          * so trim this into the part that
1174                                          * preceeds the frame buffer.
1175                                          */
1176                                         local_max = screen_info.lfb_base - 1;
1177                                         range_min = fb_end;
1178                                 } else {
1179                                         range_min = fb_end;
1180                                         continue;
1181                                 }
1182                         }
1183
1184                         start = (local_min + align - 1) & ~(align - 1);
1185                         for (; start + size - 1 <= local_max; start += align) {
1186                                 *new = request_mem_region_exclusive(start, size,
1187                                                                     dev_n);
1188                                 if (*new)
1189                                         return 0;
1190                         }
1191                 }
1192         }
1193
1194         return -ENXIO;
1195 }
1196 EXPORT_SYMBOL_GPL(vmbus_allocate_mmio);
1197
1198 /**
1199  * vmbus_cpu_number_to_vp_number() - Map CPU to VP.
1200  * @cpu_number: CPU number in Linux terms
1201  *
1202  * This function returns the mapping between the Linux processor
1203  * number and the hypervisor's virtual processor number, useful
1204  * in making hypercalls and such that talk about specific
1205  * processors.
1206  *
1207  * Return: Virtual processor number in Hyper-V terms
1208  */
1209 int vmbus_cpu_number_to_vp_number(int cpu_number)
1210 {
1211         return hv_context.vp_index[cpu_number];
1212 }
1213 EXPORT_SYMBOL_GPL(vmbus_cpu_number_to_vp_number);
1214
1215 static int vmbus_acpi_add(struct acpi_device *device)
1216 {
1217         acpi_status result;
1218         int ret_val = -ENODEV;
1219         struct acpi_device *ancestor;
1220
1221         hv_acpi_dev = device;
1222
1223         result = acpi_walk_resources(device->handle, METHOD_NAME__CRS,
1224                                         vmbus_walk_resources, NULL);
1225
1226         if (ACPI_FAILURE(result))
1227                 goto acpi_walk_err;
1228         /*
1229          * Some ancestor of the vmbus acpi device (Gen1 or Gen2
1230          * firmware) is the VMOD that has the mmio ranges. Get that.
1231          */
1232         for (ancestor = device->parent; ancestor; ancestor = ancestor->parent) {
1233                 result = acpi_walk_resources(ancestor->handle, METHOD_NAME__CRS,
1234                                              vmbus_walk_resources, NULL);
1235
1236                 if (ACPI_FAILURE(result))
1237                         continue;
1238                 if (hyperv_mmio)
1239                         break;
1240         }
1241         ret_val = 0;
1242
1243 acpi_walk_err:
1244         complete(&probe_event);
1245         if (ret_val)
1246                 vmbus_acpi_remove(device);
1247         return ret_val;
1248 }
1249
1250 static const struct acpi_device_id vmbus_acpi_device_ids[] = {
1251         {"VMBUS", 0},
1252         {"VMBus", 0},
1253         {"", 0},
1254 };
1255 MODULE_DEVICE_TABLE(acpi, vmbus_acpi_device_ids);
1256
1257 static struct acpi_driver vmbus_acpi_driver = {
1258         .name = "vmbus",
1259         .ids = vmbus_acpi_device_ids,
1260         .ops = {
1261                 .add = vmbus_acpi_add,
1262                 .remove = vmbus_acpi_remove,
1263         },
1264 };
1265
1266 static void hv_kexec_handler(void)
1267 {
1268         int cpu;
1269
1270         hv_synic_clockevents_cleanup();
1271         vmbus_initiate_unload();
1272         for_each_online_cpu(cpu)
1273                 smp_call_function_single(cpu, hv_synic_cleanup, NULL, 1);
1274         hv_cleanup();
1275 };
1276
1277 static void hv_crash_handler(struct pt_regs *regs)
1278 {
1279         vmbus_initiate_unload();
1280         /*
1281          * In crash handler we can't schedule synic cleanup for all CPUs,
1282          * doing the cleanup for current CPU only. This should be sufficient
1283          * for kdump.
1284          */
1285         hv_synic_cleanup(NULL);
1286         hv_cleanup();
1287 };
1288
1289 static int __init hv_acpi_init(void)
1290 {
1291         int ret, t;
1292
1293         if (x86_hyper != &x86_hyper_ms_hyperv)
1294                 return -ENODEV;
1295
1296         init_completion(&probe_event);
1297
1298         /*
1299          * Get ACPI resources first.
1300          */
1301         ret = acpi_bus_register_driver(&vmbus_acpi_driver);
1302
1303         if (ret)
1304                 return ret;
1305
1306         t = wait_for_completion_timeout(&probe_event, 5*HZ);
1307         if (t == 0) {
1308                 ret = -ETIMEDOUT;
1309                 goto cleanup;
1310         }
1311
1312         ret = vmbus_bus_init();
1313         if (ret)
1314                 goto cleanup;
1315
1316         hv_setup_kexec_handler(hv_kexec_handler);
1317         hv_setup_crash_handler(hv_crash_handler);
1318
1319         return 0;
1320
1321 cleanup:
1322         acpi_bus_unregister_driver(&vmbus_acpi_driver);
1323         hv_acpi_dev = NULL;
1324         return ret;
1325 }
1326
1327 static void __exit vmbus_exit(void)
1328 {
1329         int cpu;
1330
1331         hv_remove_kexec_handler();
1332         hv_remove_crash_handler();
1333         vmbus_connection.conn_state = DISCONNECTED;
1334         hv_synic_clockevents_cleanup();
1335         vmbus_disconnect();
1336         hv_remove_vmbus_irq();
1337         tasklet_kill(&msg_dpc);
1338         vmbus_free_channels();
1339         if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
1340                 unregister_die_notifier(&hyperv_die_block);
1341                 atomic_notifier_chain_unregister(&panic_notifier_list,
1342                                                  &hyperv_panic_block);
1343         }
1344         bus_unregister(&hv_bus);
1345         hv_cleanup();
1346         for_each_online_cpu(cpu) {
1347                 tasklet_kill(hv_context.event_dpc[cpu]);
1348                 smp_call_function_single(cpu, hv_synic_cleanup, NULL, 1);
1349         }
1350         hv_synic_free();
1351         acpi_bus_unregister_driver(&vmbus_acpi_driver);
1352         if (vmbus_proto_version > VERSION_WIN7)
1353                 cpu_hotplug_enable();
1354 }
1355
1356
1357 MODULE_LICENSE("GPL");
1358
1359 subsys_initcall(hv_acpi_init);
1360 module_exit(vmbus_exit);