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 completion probe_event;
  49
  50
  51 static void hyperv_report_panic(struct pt_regs *regs)
  52 {
  53         static bool panic_reported;
  54
  55         /*
  56          * We prefer to report panic on 'die' chain as we have proper
  57          * registers to report, but if we miss it (e.g. on BUG()) we need
  58          * to report it on 'panic'.
  59          */
  60         if (panic_reported)
  61                 return;
  62         panic_reported = true;
  63
  64         wrmsrl(HV_X64_MSR_CRASH_P0, regs->ip);
  65         wrmsrl(HV_X64_MSR_CRASH_P1, regs->ax);
  66         wrmsrl(HV_X64_MSR_CRASH_P2, regs->bx);
  67         wrmsrl(HV_X64_MSR_CRASH_P3, regs->cx);
  68         wrmsrl(HV_X64_MSR_CRASH_P4, regs->dx);
  69
  70         /*
  71          * Let Hyper-V know there is crash data available
  72          */
  73         wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
  74 }
  75
  76 static int hyperv_panic_event(struct notifier_block *nb, unsigned long val,
  77                               void *args)
  78 {
  79         struct pt_regs *regs;
  80
  81         regs = current_pt_regs();
  82
  83         hyperv_report_panic(regs);
  84         return NOTIFY_DONE;
  85 }
  86
  87 static int hyperv_die_event(struct notifier_block *nb, unsigned long val,
  88                             void *args)
  89 {
  90         struct die_args *die = (struct die_args *)args;
  91         struct pt_regs *regs = die->regs;
  92
  93         hyperv_report_panic(regs);
  94         return NOTIFY_DONE;
  95 }
  96
  97 static struct notifier_block hyperv_die_block = {
  98         .notifier_call = hyperv_die_event,
  99 };
 100 static struct notifier_block hyperv_panic_block = {
 101         .notifier_call = hyperv_panic_event,
 102 };
 103
 104 struct resource *hyperv_mmio;
 105
 106 static int vmbus_exists(void)
 107 {
 108         if (hv_acpi_dev == NULL)
 109                 return -ENODEV;
 110
 111         return 0;
 112 }
 113
 114 #define VMBUS_ALIAS_LEN ((sizeof((struct hv_vmbus_device_id *)0)->guid) * 2)
 115 static void print_alias_name(struct hv_device *hv_dev, char *alias_name)
 116 {
 117         int i;
 118         for (i = 0; i < VMBUS_ALIAS_LEN; i += 2)
 119                 sprintf(&alias_name[i], "%02x", hv_dev->dev_type.b[i/2]);
 120 }
 121
 122 static u8 channel_monitor_group(struct vmbus_channel *channel)
 123 {
 124         return (u8)channel->offermsg.monitorid / 32;
 125 }
 126
 127 static u8 channel_monitor_offset(struct vmbus_channel *channel)
 128 {
 129         return (u8)channel->offermsg.monitorid % 32;
 130 }
 131
 132 static u32 channel_pending(struct vmbus_channel *channel,
 133                            struct hv_monitor_page *monitor_page)
 134 {
 135         u8 monitor_group = channel_monitor_group(channel);
 136         return monitor_page->trigger_group[monitor_group].pending;
 137 }
 138
 139 static u32 channel_latency(struct vmbus_channel *channel,
 140                            struct hv_monitor_page *monitor_page)
 141 {
 142         u8 monitor_group = channel_monitor_group(channel);
 143         u8 monitor_offset = channel_monitor_offset(channel);
 144         return monitor_page->latency[monitor_group][monitor_offset];
 145 }
 146
 147 static u32 channel_conn_id(struct vmbus_channel *channel,
 148                            struct hv_monitor_page *monitor_page)
 149 {
 150         u8 monitor_group = channel_monitor_group(channel);
 151         u8 monitor_offset = channel_monitor_offset(channel);
 152         return monitor_page->parameter[monitor_group][monitor_offset].connectionid.u.id;
 153 }
 154
 155 static ssize_t id_show(struct device *dev, struct device_attribute *dev_attr,
 156                        char *buf)
 157 {
 158         struct hv_device *hv_dev = device_to_hv_device(dev);
 159
 160         if (!hv_dev->channel)
 161                 return -ENODEV;
 162         return sprintf(buf, "%d\n", hv_dev->channel->offermsg.child_relid);
 163 }
 164 static DEVICE_ATTR_RO(id);
 165
 166 static ssize_t state_show(struct device *dev, struct device_attribute *dev_attr,
 167                           char *buf)
 168 {
 169         struct hv_device *hv_dev = device_to_hv_device(dev);
 170
 171         if (!hv_dev->channel)
 172                 return -ENODEV;
 173         return sprintf(buf, "%d\n", hv_dev->channel->state);
 174 }
 175 static DEVICE_ATTR_RO(state);
 176
 177 static ssize_t monitor_id_show(struct device *dev,
 178                                struct device_attribute *dev_attr, char *buf)
 179 {
 180         struct hv_device *hv_dev = device_to_hv_device(dev);
 181
 182         if (!hv_dev->channel)
 183                 return -ENODEV;
 184         return sprintf(buf, "%d\n", hv_dev->channel->offermsg.monitorid);
 185 }
 186 static DEVICE_ATTR_RO(monitor_id);
 187
 188 static ssize_t class_id_show(struct device *dev,
 189                                struct device_attribute *dev_attr, char *buf)
 190 {
 191         struct hv_device *hv_dev = device_to_hv_device(dev);
 192
 193         if (!hv_dev->channel)
 194                 return -ENODEV;
 195         return sprintf(buf, "{%pUl}\n",
 196                        hv_dev->channel->offermsg.offer.if_type.b);
 197 }
 198 static DEVICE_ATTR_RO(class_id);
 199
 200 static ssize_t device_id_show(struct device *dev,
 201                               struct device_attribute *dev_attr, char *buf)
 202 {
 203         struct hv_device *hv_dev = device_to_hv_device(dev);
 204
 205         if (!hv_dev->channel)
 206                 return -ENODEV;
 207         return sprintf(buf, "{%pUl}\n",
 208                        hv_dev->channel->offermsg.offer.if_instance.b);
 209 }
 210 static DEVICE_ATTR_RO(device_id);
 211
 212 static ssize_t modalias_show(struct device *dev,
 213                              struct device_attribute *dev_attr, char *buf)
 214 {
 215         struct hv_device *hv_dev = device_to_hv_device(dev);
 216         char alias_name[VMBUS_ALIAS_LEN + 1];
 217
 218         print_alias_name(hv_dev, alias_name);
 219         return sprintf(buf, "vmbus:%s\n", alias_name);
 220 }
 221 static DEVICE_ATTR_RO(modalias);
 222
 223 static ssize_t server_monitor_pending_show(struct device *dev,
 224                                            struct device_attribute *dev_attr,
 225                                            char *buf)
 226 {
 227         struct hv_device *hv_dev = device_to_hv_device(dev);
 228
 229         if (!hv_dev->channel)
 230                 return -ENODEV;
 231         return sprintf(buf, "%d\n",
 232                        channel_pending(hv_dev->channel,
 233                                        vmbus_connection.monitor_pages[1]));
 234 }
 235 static DEVICE_ATTR_RO(server_monitor_pending);
 236
 237 static ssize_t client_monitor_pending_show(struct device *dev,
 238                                            struct device_attribute *dev_attr,
 239                                            char *buf)
 240 {
 241         struct hv_device *hv_dev = device_to_hv_device(dev);
 242
 243         if (!hv_dev->channel)
 244                 return -ENODEV;
 245         return sprintf(buf, "%d\n",
 246                        channel_pending(hv_dev->channel,
 247                                        vmbus_connection.monitor_pages[1]));
 248 }
 249 static DEVICE_ATTR_RO(client_monitor_pending);
 250
 251 static ssize_t server_monitor_latency_show(struct device *dev,
 252                                            struct device_attribute *dev_attr,
 253                                            char *buf)
 254 {
 255         struct hv_device *hv_dev = device_to_hv_device(dev);
 256
 257         if (!hv_dev->channel)
 258                 return -ENODEV;
 259         return sprintf(buf, "%d\n",
 260                        channel_latency(hv_dev->channel,
 261                                        vmbus_connection.monitor_pages[0]));
 262 }
 263 static DEVICE_ATTR_RO(server_monitor_latency);
 264
 265 static ssize_t client_monitor_latency_show(struct device *dev,
 266                                            struct device_attribute *dev_attr,
 267                                            char *buf)
 268 {
 269         struct hv_device *hv_dev = device_to_hv_device(dev);
 270
 271         if (!hv_dev->channel)
 272                 return -ENODEV;
 273         return sprintf(buf, "%d\n",
 274                        channel_latency(hv_dev->channel,
 275                                        vmbus_connection.monitor_pages[1]));
 276 }
 277 static DEVICE_ATTR_RO(client_monitor_latency);
 278
 279 static ssize_t server_monitor_conn_id_show(struct device *dev,
 280                                            struct device_attribute *dev_attr,
 281                                            char *buf)
 282 {
 283         struct hv_device *hv_dev = device_to_hv_device(dev);
 284
 285         if (!hv_dev->channel)
 286                 return -ENODEV;
 287         return sprintf(buf, "%d\n",
 288                        channel_conn_id(hv_dev->channel,
 289                                        vmbus_connection.monitor_pages[0]));
 290 }
 291 static DEVICE_ATTR_RO(server_monitor_conn_id);
 292
 293 static ssize_t client_monitor_conn_id_show(struct device *dev,
 294                                            struct device_attribute *dev_attr,
 295                                            char *buf)
 296 {
 297         struct hv_device *hv_dev = device_to_hv_device(dev);
 298
 299         if (!hv_dev->channel)
 300                 return -ENODEV;
 301         return sprintf(buf, "%d\n",
 302                        channel_conn_id(hv_dev->channel,
 303                                        vmbus_connection.monitor_pages[1]));
 304 }
 305 static DEVICE_ATTR_RO(client_monitor_conn_id);
 306
 307 static ssize_t out_intr_mask_show(struct device *dev,
 308                                   struct device_attribute *dev_attr, char *buf)
 309 {
 310         struct hv_device *hv_dev = device_to_hv_device(dev);
 311         struct hv_ring_buffer_debug_info outbound;
 312
 313         if (!hv_dev->channel)
 314                 return -ENODEV;
 315         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 316         return sprintf(buf, "%d\n", outbound.current_interrupt_mask);
 317 }
 318 static DEVICE_ATTR_RO(out_intr_mask);
 319
 320 static ssize_t out_read_index_show(struct device *dev,
 321                                    struct device_attribute *dev_attr, char *buf)
 322 {
 323         struct hv_device *hv_dev = device_to_hv_device(dev);
 324         struct hv_ring_buffer_debug_info outbound;
 325
 326         if (!hv_dev->channel)
 327                 return -ENODEV;
 328         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 329         return sprintf(buf, "%d\n", outbound.current_read_index);
 330 }
 331 static DEVICE_ATTR_RO(out_read_index);
 332
 333 static ssize_t out_write_index_show(struct device *dev,
 334                                     struct device_attribute *dev_attr,
 335                                     char *buf)
 336 {
 337         struct hv_device *hv_dev = device_to_hv_device(dev);
 338         struct hv_ring_buffer_debug_info outbound;
 339
 340         if (!hv_dev->channel)
 341                 return -ENODEV;
 342         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 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
 354         if (!hv_dev->channel)
 355                 return -ENODEV;
 356         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 357         return sprintf(buf, "%d\n", outbound.bytes_avail_toread);
 358 }
 359 static DEVICE_ATTR_RO(out_read_bytes_avail);
 360
 361 static ssize_t out_write_bytes_avail_show(struct device *dev,
 362                                           struct device_attribute *dev_attr,
 363                                           char *buf)
 364 {
 365         struct hv_device *hv_dev = device_to_hv_device(dev);
 366         struct hv_ring_buffer_debug_info outbound;
 367
 368         if (!hv_dev->channel)
 369                 return -ENODEV;
 370         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 371         return sprintf(buf, "%d\n", outbound.bytes_avail_towrite);
 372 }
 373 static DEVICE_ATTR_RO(out_write_bytes_avail);
 374
 375 static ssize_t in_intr_mask_show(struct device *dev,
 376                                  struct device_attribute *dev_attr, char *buf)
 377 {
 378         struct hv_device *hv_dev = device_to_hv_device(dev);
 379         struct hv_ring_buffer_debug_info inbound;
 380
 381         if (!hv_dev->channel)
 382                 return -ENODEV;
 383         hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 384         return sprintf(buf, "%d\n", inbound.current_interrupt_mask);
 385 }
 386 static DEVICE_ATTR_RO(in_intr_mask);
 387
 388 static ssize_t in_read_index_show(struct device *dev,
 389                                   struct device_attribute *dev_attr, char *buf)
 390 {
 391         struct hv_device *hv_dev = device_to_hv_device(dev);
 392         struct hv_ring_buffer_debug_info inbound;
 393
 394         if (!hv_dev->channel)
 395                 return -ENODEV;
 396         hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 397         return sprintf(buf, "%d\n", inbound.current_read_index);
 398 }
 399 static DEVICE_ATTR_RO(in_read_index);
 400
 401 static ssize_t in_write_index_show(struct device *dev,
 402                                    struct device_attribute *dev_attr, char *buf)
 403 {
 404         struct hv_device *hv_dev = device_to_hv_device(dev);
 405         struct hv_ring_buffer_debug_info inbound;
 406
 407         if (!hv_dev->channel)
 408                 return -ENODEV;
 409         hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 410         return sprintf(buf, "%d\n", inbound.current_write_index);
 411 }
 412 static DEVICE_ATTR_RO(in_write_index);
 413
 414 static ssize_t in_read_bytes_avail_show(struct device *dev,
 415                                         struct device_attribute *dev_attr,
 416                                         char *buf)
 417 {
 418         struct hv_device *hv_dev = device_to_hv_device(dev);
 419         struct hv_ring_buffer_debug_info inbound;
 420
 421         if (!hv_dev->channel)
 422                 return -ENODEV;
 423         hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 424         return sprintf(buf, "%d\n", inbound.bytes_avail_toread);
 425 }
 426 static DEVICE_ATTR_RO(in_read_bytes_avail);
 427
 428 static ssize_t in_write_bytes_avail_show(struct device *dev,
 429                                          struct device_attribute *dev_attr,
 430                                          char *buf)
 431 {
 432         struct hv_device *hv_dev = device_to_hv_device(dev);
 433         struct hv_ring_buffer_debug_info inbound;
 434
 435         if (!hv_dev->channel)
 436                 return -ENODEV;
 437         hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 438         return sprintf(buf, "%d\n", inbound.bytes_avail_towrite);
 439 }
 440 static DEVICE_ATTR_RO(in_write_bytes_avail);
 441
 442 static ssize_t channel_vp_mapping_show(struct device *dev,
 443                                        struct device_attribute *dev_attr,
 444                                        char *buf)
 445 {
 446         struct hv_device *hv_dev = device_to_hv_device(dev);
 447         struct vmbus_channel *channel = hv_dev->channel, *cur_sc;
 448         unsigned long flags;
 449         int buf_size = PAGE_SIZE, n_written, tot_written;
 450         struct list_head *cur;
 451
 452         if (!channel)
 453                 return -ENODEV;
 454
 455         tot_written = snprintf(buf, buf_size, "%u:%u\n",
 456                 channel->offermsg.child_relid, channel->target_cpu);
 457
 458         spin_lock_irqsave(&channel->lock, flags);
 459
 460         list_for_each(cur, &channel->sc_list) {
 461                 if (tot_written >= buf_size - 1)
 462                         break;
 463
 464                 cur_sc = list_entry(cur, struct vmbus_channel, sc_list);
 465                 n_written = scnprintf(buf + tot_written,
 466                                      buf_size - tot_written,
 467                                      "%u:%u\n",
 468                                      cur_sc->offermsg.child_relid,
 469                                      cur_sc->target_cpu);
 470                 tot_written += n_written;
 471         }
 472
 473         spin_unlock_irqrestore(&channel->lock, flags);
 474
 475         return tot_written;
 476 }
 477 static DEVICE_ATTR_RO(channel_vp_mapping);
 478
 479 static ssize_t vendor_show(struct device *dev,
 480                            struct device_attribute *dev_attr,
 481                            char *buf)
 482 {
 483         struct hv_device *hv_dev = device_to_hv_device(dev);
 484         return sprintf(buf, "0x%x\n", hv_dev->vendor_id);
 485 }
 486 static DEVICE_ATTR_RO(vendor);
 487
 488 static ssize_t device_show(struct device *dev,
 489                            struct device_attribute *dev_attr,
 490                            char *buf)
 491 {
 492         struct hv_device *hv_dev = device_to_hv_device(dev);
 493         return sprintf(buf, "0x%x\n", hv_dev->device_id);
 494 }
 495 static DEVICE_ATTR_RO(device);
 496
 497 /* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
 498 static struct attribute *vmbus_attrs[] = {
 499         &dev_attr_id.attr,
 500         &dev_attr_state.attr,
 501         &dev_attr_monitor_id.attr,
 502         &dev_attr_class_id.attr,
 503         &dev_attr_device_id.attr,
 504         &dev_attr_modalias.attr,
 505         &dev_attr_server_monitor_pending.attr,
 506         &dev_attr_client_monitor_pending.attr,
 507         &dev_attr_server_monitor_latency.attr,
 508         &dev_attr_client_monitor_latency.attr,
 509         &dev_attr_server_monitor_conn_id.attr,
 510         &dev_attr_client_monitor_conn_id.attr,
 511         &dev_attr_out_intr_mask.attr,
 512         &dev_attr_out_read_index.attr,
 513         &dev_attr_out_write_index.attr,
 514         &dev_attr_out_read_bytes_avail.attr,
 515         &dev_attr_out_write_bytes_avail.attr,
 516         &dev_attr_in_intr_mask.attr,
 517         &dev_attr_in_read_index.attr,
 518         &dev_attr_in_write_index.attr,
 519         &dev_attr_in_read_bytes_avail.attr,
 520         &dev_attr_in_write_bytes_avail.attr,
 521         &dev_attr_channel_vp_mapping.attr,
 522         &dev_attr_vendor.attr,
 523         &dev_attr_device.attr,
 524         NULL,
 525 };
 526 ATTRIBUTE_GROUPS(vmbus);
 527
 528 /*
 529  * vmbus_uevent - add uevent for our device
 530  *
 531  * This routine is invoked when a device is added or removed on the vmbus to
 532  * generate a uevent to udev in the userspace. The udev will then look at its
 533  * rule and the uevent generated here to load the appropriate driver
 534  *
 535  * The alias string will be of the form vmbus:guid where guid is the string
 536  * representation of the device guid (each byte of the guid will be
 537  * represented with two hex characters.
 538  */
 539 static int vmbus_uevent(struct device *device, struct kobj_uevent_env *env)
 540 {
 541         struct hv_device *dev = device_to_hv_device(device);
 542         int ret;
 543         char alias_name[VMBUS_ALIAS_LEN + 1];
 544
 545         print_alias_name(dev, alias_name);
 546         ret = add_uevent_var(env, "MODALIAS=vmbus:%s", alias_name);
 547         return ret;
 548 }
 549
 550 static const uuid_le null_guid;
 551
 552 static inline bool is_null_guid(const uuid_le *guid)
 553 {
 554         if (uuid_le_cmp(*guid, null_guid))
 555                 return false;
 556         return true;
 557 }
 558
 559 /*
 560  * Return a matching hv_vmbus_device_id pointer.
 561  * If there is no match, return NULL.
 562  */
 563 static const struct hv_vmbus_device_id *hv_vmbus_get_id(
 564                                         const struct hv_vmbus_device_id *id,
 565                                         const uuid_le *guid)
 566 {
 567         for (; !is_null_guid(&id->guid); id++)
 568                 if (!uuid_le_cmp(id->guid, *guid))
 569                         return id;
 570
 571         return NULL;
 572 }
 573
 574
 575
 576 /*
 577  * vmbus_match - Attempt to match the specified device to the specified driver
 578  */
 579 static int vmbus_match(struct device *device, struct device_driver *driver)
 580 {
 581         struct hv_driver *drv = drv_to_hv_drv(driver);
 582         struct hv_device *hv_dev = device_to_hv_device(device);
 583
 584         /* The hv_sock driver handles all hv_sock offers. */
 585         if (is_hvsock_channel(hv_dev->channel))
 586                 return drv->hvsock;
 587
 588         if (hv_vmbus_get_id(drv->id_table, &hv_dev->dev_type))
 589                 return 1;
 590
 591         return 0;
 592 }
 593
 594 /*
 595  * vmbus_probe - Add the new vmbus's child device
 596  */
 597 static int vmbus_probe(struct device *child_device)
 598 {
 599         int ret = 0;
 600         struct hv_driver *drv =
 601                         drv_to_hv_drv(child_device->driver);
 602         struct hv_device *dev = device_to_hv_device(child_device);
 603         const struct hv_vmbus_device_id *dev_id;
 604
 605         dev_id = hv_vmbus_get_id(drv->id_table, &dev->dev_type);
 606         if (drv->probe) {
 607                 ret = drv->probe(dev, dev_id);
 608                 if (ret != 0)
 609                         pr_err("probe failed for device %s (%d)\n",
 610                                dev_name(child_device), ret);
 611
 612         } else {
 613                 pr_err("probe not set for driver %s\n",
 614                        dev_name(child_device));
 615                 ret = -ENODEV;
 616         }
 617         return ret;
 618 }
 619
 620 /*
 621  * vmbus_remove - Remove a vmbus device
 622  */
 623 static int vmbus_remove(struct device *child_device)
 624 {
 625         struct hv_driver *drv;
 626         struct hv_device *dev = device_to_hv_device(child_device);
 627
 628         if (child_device->driver) {
 629                 drv = drv_to_hv_drv(child_device->driver);
 630                 if (drv->remove)
 631                         drv->remove(dev);
 632         }
 633
 634         return 0;
 635 }
 636
 637
 638 /*
 639  * vmbus_shutdown - Shutdown a vmbus device
 640  */
 641 static void vmbus_shutdown(struct device *child_device)
 642 {
 643         struct hv_driver *drv;
 644         struct hv_device *dev = device_to_hv_device(child_device);
 645
 646
 647         /* The device may not be attached yet */
 648         if (!child_device->driver)
 649                 return;
 650
 651         drv = drv_to_hv_drv(child_device->driver);
 652
 653         if (drv->shutdown)
 654                 drv->shutdown(dev);
 655
 656         return;
 657 }
 658
 659
 660 /*
 661  * vmbus_device_release - Final callback release of the vmbus child device
 662  */
 663 static void vmbus_device_release(struct device *device)
 664 {
 665         struct hv_device *hv_dev = device_to_hv_device(device);
 666         struct vmbus_channel *channel = hv_dev->channel;
 667
 668         hv_process_channel_removal(channel,
 669                                    channel->offermsg.child_relid);
 670         kfree(hv_dev);
 671
 672 }
 673
 674 /* The one and only one */
 675 static struct bus_type  hv_bus = {
 676         .name =         "vmbus",
 677         .match =                vmbus_match,
 678         .shutdown =             vmbus_shutdown,
 679         .remove =               vmbus_remove,
 680         .probe =                vmbus_probe,
 681         .uevent =               vmbus_uevent,
 682         .dev_groups =           vmbus_groups,
 683 };
 684
 685 struct onmessage_work_context {
 686         struct work_struct work;
 687         struct hv_message msg;
 688 };
 689
 690 static void vmbus_onmessage_work(struct work_struct *work)
 691 {
 692         struct onmessage_work_context *ctx;
 693
 694         /* Do not process messages if we're in DISCONNECTED state */
 695         if (vmbus_connection.conn_state == DISCONNECTED)
 696                 return;
 697
 698         ctx = container_of(work, struct onmessage_work_context,
 699                            work);
 700         vmbus_onmessage(&ctx->msg);
 701         kfree(ctx);
 702 }
 703
 704 static void hv_process_timer_expiration(struct hv_message *msg, int cpu)
 705 {
 706         struct clock_event_device *dev = hv_context.clk_evt[cpu];
 707
 708         if (dev->event_handler)
 709                 dev->event_handler(dev);
 710
 711         vmbus_signal_eom(msg);
 712 }
 713
 714 void vmbus_on_msg_dpc(unsigned long data)
 715 {
 716         int cpu = smp_processor_id();
 717         void *page_addr = hv_context.synic_message_page[cpu];
 718         struct hv_message *msg = (struct hv_message *)page_addr +
 719                                   VMBUS_MESSAGE_SINT;
 720         struct vmbus_channel_message_header *hdr;
 721         struct vmbus_channel_message_table_entry *entry;
 722         struct onmessage_work_context *ctx;
 723
 724         if (msg->header.message_type == HVMSG_NONE)
 725                 /* no msg */
 726                 return;
 727
 728         hdr = (struct vmbus_channel_message_header *)msg->u.payload;
 729
 730         if (hdr->msgtype >= CHANNELMSG_COUNT) {
 731                 WARN_ONCE(1, "unknown msgtype=%d\n", hdr->msgtype);
 732                 goto msg_handled;
 733         }
 734
 735         entry = &channel_message_table[hdr->msgtype];
 736         if (entry->handler_type == VMHT_BLOCKING) {
 737                 ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC);
 738                 if (ctx == NULL)
 739                         return;
 740
 741                 INIT_WORK(&ctx->work, vmbus_onmessage_work);
 742                 memcpy(&ctx->msg, msg, sizeof(*msg));
 743
 744                 queue_work(vmbus_connection.work_queue, &ctx->work);
 745         } else
 746                 entry->message_handler(hdr);
 747
 748 msg_handled:
 749         vmbus_signal_eom(msg);
 750 }
 751
 752 static void vmbus_isr(void)
 753 {
 754         int cpu = smp_processor_id();
 755         void *page_addr;
 756         struct hv_message *msg;
 757         union hv_synic_event_flags *event;
 758         bool handled = false;
 759
 760         page_addr = hv_context.synic_event_page[cpu];
 761         if (page_addr == NULL)
 762                 return;
 763
 764         event = (union hv_synic_event_flags *)page_addr +
 765                                          VMBUS_MESSAGE_SINT;
 766         /*
 767          * Check for events before checking for messages. This is the order
 768          * in which events and messages are checked in Windows guests on
 769          * Hyper-V, and the Windows team suggested we do the same.
 770          */
 771
 772         if ((vmbus_proto_version == VERSION_WS2008) ||
 773                 (vmbus_proto_version == VERSION_WIN7)) {
 774
 775                 /* Since we are a child, we only need to check bit 0 */
 776                 if (sync_test_and_clear_bit(0,
 777                         (unsigned long *) &event->flags32[0])) {
 778                         handled = true;
 779                 }
 780         } else {
 781                 /*
 782                  * Our host is win8 or above. The signaling mechanism
 783                  * has changed and we can directly look at the event page.
 784                  * If bit n is set then we have an interrup on the channel
 785                  * whose id is n.
 786                  */
 787                 handled = true;
 788         }
 789
 790         if (handled)
 791                 tasklet_schedule(hv_context.event_dpc[cpu]);
 792
 793
 794         page_addr = hv_context.synic_message_page[cpu];
 795         msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
 796
 797         /* Check if there are actual msgs to be processed */
 798         if (msg->header.message_type != HVMSG_NONE) {
 799                 if (msg->header.message_type == HVMSG_TIMER_EXPIRED)
 800                         hv_process_timer_expiration(msg, cpu);
 801                 else
 802                         tasklet_schedule(hv_context.msg_dpc[cpu]);
 803         }
 804 }
 805
 806
 807 /*
 808  * vmbus_bus_init -Main vmbus driver initialization routine.
 809  *
 810  * Here, we
 811  *      - initialize the vmbus driver context
 812  *      - invoke the vmbus hv main init routine
 813  *      - retrieve the channel offers
 814  */
 815 static int vmbus_bus_init(void)
 816 {
 817         int ret;
 818
 819         /* Hypervisor initialization...setup hypercall page..etc */
 820         ret = hv_init();
 821         if (ret != 0) {
 822                 pr_err("Unable to initialize the hypervisor - 0x%x\n", ret);
 823                 return ret;
 824         }
 825
 826         ret = bus_register(&hv_bus);
 827         if (ret)
 828                 goto err_cleanup;
 829
 830         hv_setup_vmbus_irq(vmbus_isr);
 831
 832         ret = hv_synic_alloc();
 833         if (ret)
 834                 goto err_alloc;
 835         /*
 836          * Initialize the per-cpu interrupt state and
 837          * connect to the host.
 838          */
 839         on_each_cpu(hv_synic_init, NULL, 1);
 840         ret = vmbus_connect();
 841         if (ret)
 842                 goto err_connect;
 843
 844         if (vmbus_proto_version > VERSION_WIN7)
 845                 cpu_hotplug_disable();
 846
 847         /*
 848          * Only register if the crash MSRs are available
 849          */
 850         if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
 851                 register_die_notifier(&hyperv_die_block);
 852                 atomic_notifier_chain_register(&panic_notifier_list,
 853                                                &hyperv_panic_block);
 854         }
 855
 856         vmbus_request_offers();
 857
 858         return 0;
 859
 860 err_connect:
 861         on_each_cpu(hv_synic_cleanup, NULL, 1);
 862 err_alloc:
 863         hv_synic_free();
 864         hv_remove_vmbus_irq();
 865
 866         bus_unregister(&hv_bus);
 867
 868 err_cleanup:
 869         hv_cleanup();
 870
 871         return ret;
 872 }
 873
 874 /**
 875  * __vmbus_child_driver_register() - Register a vmbus's driver
 876  * @hv_driver: Pointer to driver structure you want to register
 877  * @owner: owner module of the drv
 878  * @mod_name: module name string
 879  *
 880  * Registers the given driver with Linux through the 'driver_register()' call
 881  * and sets up the hyper-v vmbus handling for this driver.
 882  * It will return the state of the 'driver_register()' call.
 883  *
 884  */
 885 int __vmbus_driver_register(struct hv_driver *hv_driver, struct module *owner, const char *mod_name)
 886 {
 887         int ret;
 888
 889         pr_info("registering driver %s\n", hv_driver->name);
 890
 891         ret = vmbus_exists();
 892         if (ret < 0)
 893                 return ret;
 894
 895         hv_driver->driver.name = hv_driver->name;
 896         hv_driver->driver.owner = owner;
 897         hv_driver->driver.mod_name = mod_name;
 898         hv_driver->driver.bus = &hv_bus;
 899
 900         ret = driver_register(&hv_driver->driver);
 901
 902         return ret;
 903 }
 904 EXPORT_SYMBOL_GPL(__vmbus_driver_register);
 905
 906 /**
 907  * vmbus_driver_unregister() - Unregister a vmbus's driver
 908  * @hv_driver: Pointer to driver structure you want to
 909  *             un-register
 910  *
 911  * Un-register the given driver that was previous registered with a call to
 912  * vmbus_driver_register()
 913  */
 914 void vmbus_driver_unregister(struct hv_driver *hv_driver)
 915 {
 916         pr_info("unregistering driver %s\n", hv_driver->name);
 917
 918         if (!vmbus_exists())
 919                 driver_unregister(&hv_driver->driver);
 920 }
 921 EXPORT_SYMBOL_GPL(vmbus_driver_unregister);
 922
 923 /*
 924  * vmbus_device_create - Creates and registers a new child device
 925  * on the vmbus.
 926  */
 927 struct hv_device *vmbus_device_create(const uuid_le *type,
 928                                       const uuid_le *instance,
 929                                       struct vmbus_channel *channel)
 930 {
 931         struct hv_device *child_device_obj;
 932
 933         child_device_obj = kzalloc(sizeof(struct hv_device), GFP_KERNEL);
 934         if (!child_device_obj) {
 935                 pr_err("Unable to allocate device object for child device\n");
 936                 return NULL;
 937         }
 938
 939         child_device_obj->channel = channel;
 940         memcpy(&child_device_obj->dev_type, type, sizeof(uuid_le));
 941         memcpy(&child_device_obj->dev_instance, instance,
 942                sizeof(uuid_le));
 943         child_device_obj->vendor_id = 0x1414; /* MSFT vendor ID */
 944
 945
 946         return child_device_obj;
 947 }
 948
 949 /*
 950  * vmbus_device_register - Register the child device
 951  */
 952 int vmbus_device_register(struct hv_device *child_device_obj)
 953 {
 954         int ret = 0;
 955
 956         dev_set_name(&child_device_obj->device, "vmbus_%d",
 957                      child_device_obj->channel->id);
 958
 959         child_device_obj->device.bus = &hv_bus;
 960         child_device_obj->device.parent = &hv_acpi_dev->dev;
 961         child_device_obj->device.release = vmbus_device_release;
 962
 963         /*
 964          * Register with the LDM. This will kick off the driver/device
 965          * binding...which will eventually call vmbus_match() and vmbus_probe()
 966          */
 967         ret = device_register(&child_device_obj->device);
 968
 969         if (ret)
 970                 pr_err("Unable to register child device\n");
 971         else
 972                 pr_debug("child device %s registered\n",
 973                         dev_name(&child_device_obj->device));
 974
 975         return ret;
 976 }
 977
 978 /*
 979  * vmbus_device_unregister - Remove the specified child device
 980  * from the vmbus.
 981  */
 982 void vmbus_device_unregister(struct hv_device *device_obj)
 983 {
 984         pr_debug("child device %s unregistered\n",
 985                 dev_name(&device_obj->device));
 986
 987         /*
 988          * Kick off the process of unregistering the device.
 989          * This will call vmbus_remove() and eventually vmbus_device_release()
 990          */
 991         device_unregister(&device_obj->device);
 992 }
 993
 994
 995 /*
 996  * VMBUS is an acpi enumerated device. Get the information we
 997  * need from DSDT.
 998  */
 999 #define VTPM_BASE_ADDRESS 0xfed40000
1000 static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *ctx)
1001 {
1002         resource_size_t start = 0;
1003         resource_size_t end = 0;
1004         struct resource *new_res;
1005         struct resource **old_res = &hyperv_mmio;
1006         struct resource **prev_res = NULL;
1007
1008         switch (res->type) {
1009
1010         /*
1011          * "Address" descriptors are for bus windows. Ignore
1012          * "memory" descriptors, which are for registers on
1013          * devices.
1014          */
1015         case ACPI_RESOURCE_TYPE_ADDRESS32:
1016                 start = res->data.address32.address.minimum;
1017                 end = res->data.address32.address.maximum;
1018                 break;
1019
1020         case ACPI_RESOURCE_TYPE_ADDRESS64:
1021                 start = res->data.address64.address.minimum;
1022                 end = res->data.address64.address.maximum;
1023                 break;
1024
1025         default:
1026                 /* Unused resource type */
1027                 return AE_OK;
1028
1029         }
1030         /*
1031          * Ignore ranges that are below 1MB, as they're not
1032          * necessary or useful here.
1033          */
1034         if (end < 0x100000)
1035                 return AE_OK;
1036
1037         new_res = kzalloc(sizeof(*new_res), GFP_ATOMIC);
1038         if (!new_res)
1039                 return AE_NO_MEMORY;
1040
1041         /* If this range overlaps the virtual TPM, truncate it. */
1042         if (end > VTPM_BASE_ADDRESS && start < VTPM_BASE_ADDRESS)
1043                 end = VTPM_BASE_ADDRESS;
1044
1045         new_res->name = "hyperv mmio";
1046         new_res->flags = IORESOURCE_MEM;
1047         new_res->start = start;
1048         new_res->end = end;
1049
1050         /*
1051          * Stick ranges from higher in address space at the front of the list.
1052          * If two ranges are adjacent, merge them.
1053          */
1054         do {
1055                 if (!*old_res) {
1056                         *old_res = new_res;
1057                         break;
1058                 }
1059
1060                 if (((*old_res)->end + 1) == new_res->start) {
1061                         (*old_res)->end = new_res->end;
1062                         kfree(new_res);
1063                         break;
1064                 }
1065
1066                 if ((*old_res)->start == new_res->end + 1) {
1067                         (*old_res)->start = new_res->start;
1068                         kfree(new_res);
1069                         break;
1070                 }
1071
1072                 if ((*old_res)->end < new_res->start) {
1073                         new_res->sibling = *old_res;
1074                         if (prev_res)
1075                                 (*prev_res)->sibling = new_res;
1076                         *old_res = new_res;
1077                         break;
1078                 }
1079
1080                 prev_res = old_res;
1081                 old_res = &(*old_res)->sibling;
1082
1083         } while (1);
1084
1085         return AE_OK;
1086 }
1087
1088 static int vmbus_acpi_remove(struct acpi_device *device)
1089 {
1090         struct resource *cur_res;
1091         struct resource *next_res;
1092
1093         if (hyperv_mmio) {
1094                 for (cur_res = hyperv_mmio; cur_res; cur_res = next_res) {
1095                         next_res = cur_res->sibling;
1096                         kfree(cur_res);
1097                 }
1098         }
1099
1100         return 0;
1101 }
1102
1103 /**
1104  * vmbus_allocate_mmio() - Pick a memory-mapped I/O range.
1105  * @new:                If successful, supplied a pointer to the
1106  *                      allocated MMIO space.
1107  * @device_obj:         Identifies the caller
1108  * @min:                Minimum guest physical address of the
1109  *                      allocation
1110  * @max:                Maximum guest physical address
1111  * @size:               Size of the range to be allocated
1112  * @align:              Alignment of the range to be allocated
1113  * @fb_overlap_ok:      Whether this allocation can be allowed
1114  *                      to overlap the video frame buffer.
1115  *
1116  * This function walks the resources granted to VMBus by the
1117  * _CRS object in the ACPI namespace underneath the parent
1118  * "bridge" whether that's a root PCI bus in the Generation 1
1119  * case or a Module Device in the Generation 2 case.  It then
1120  * attempts to allocate from the global MMIO pool in a way that
1121  * matches the constraints supplied in these parameters and by
1122  * that _CRS.
1123  *
1124  * Return: 0 on success, -errno on failure
1125  */
1126 int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
1127                         resource_size_t min, resource_size_t max,
1128                         resource_size_t size, resource_size_t align,
1129                         bool fb_overlap_ok)
1130 {
1131         struct resource *iter;
1132         resource_size_t range_min, range_max, start, local_min, local_max;
1133         const char *dev_n = dev_name(&device_obj->device);
1134         u32 fb_end = screen_info.lfb_base + (screen_info.lfb_size << 1);
1135         int i;
1136
1137         for (iter = hyperv_mmio; iter; iter = iter->sibling) {
1138                 if ((iter->start >= max) || (iter->end <= min))
1139                         continue;
1140
1141                 range_min = iter->start;
1142                 range_max = iter->end;
1143
1144                 /* If this range overlaps the frame buffer, split it into
1145                    two tries. */
1146                 for (i = 0; i < 2; i++) {
1147                         local_min = range_min;
1148                         local_max = range_max;
1149                         if (fb_overlap_ok || (range_min >= fb_end) ||
1150                             (range_max <= screen_info.lfb_base)) {
1151                                 i++;
1152                         } else {
1153                                 if ((range_min <= screen_info.lfb_base) &&
1154                                     (range_max >= screen_info.lfb_base)) {
1155                                         /*
1156                                          * The frame buffer is in this window,
1157                                          * so trim this into the part that
1158                                          * preceeds the frame buffer.
1159                                          */
1160                                         local_max = screen_info.lfb_base - 1;
1161                                         range_min = fb_end;
1162                                 } else {
1163                                         range_min = fb_end;
1164                                         continue;
1165                                 }
1166                         }
1167
1168                         start = (local_min + align - 1) & ~(align - 1);
1169                         for (; start + size - 1 <= local_max; start += align) {
1170                                 *new = request_mem_region_exclusive(start, size,
1171                                                                     dev_n);
1172                                 if (*new)
1173                                         return 0;
1174                         }
1175                 }
1176         }
1177
1178         return -ENXIO;
1179 }
1180 EXPORT_SYMBOL_GPL(vmbus_allocate_mmio);
1181
1182 /**
1183  * vmbus_cpu_number_to_vp_number() - Map CPU to VP.
1184  * @cpu_number: CPU number in Linux terms
1185  *
1186  * This function returns the mapping between the Linux processor
1187  * number and the hypervisor's virtual processor number, useful
1188  * in making hypercalls and such that talk about specific
1189  * processors.
1190  *
1191  * Return: Virtual processor number in Hyper-V terms
1192  */
1193 int vmbus_cpu_number_to_vp_number(int cpu_number)
1194 {
1195         return hv_context.vp_index[cpu_number];
1196 }
1197 EXPORT_SYMBOL_GPL(vmbus_cpu_number_to_vp_number);
1198
1199 static int vmbus_acpi_add(struct acpi_device *device)
1200 {
1201         acpi_status result;
1202         int ret_val = -ENODEV;
1203         struct acpi_device *ancestor;
1204
1205         hv_acpi_dev = device;
1206
1207         result = acpi_walk_resources(device->handle, METHOD_NAME__CRS,
1208                                         vmbus_walk_resources, NULL);
1209
1210         if (ACPI_FAILURE(result))
1211                 goto acpi_walk_err;
1212         /*
1213          * Some ancestor of the vmbus acpi device (Gen1 or Gen2
1214          * firmware) is the VMOD that has the mmio ranges. Get that.
1215          */
1216         for (ancestor = device->parent; ancestor; ancestor = ancestor->parent) {
1217                 result = acpi_walk_resources(ancestor->handle, METHOD_NAME__CRS,
1218                                              vmbus_walk_resources, NULL);
1219
1220                 if (ACPI_FAILURE(result))
1221                         continue;
1222                 if (hyperv_mmio)
1223                         break;
1224         }
1225         ret_val = 0;
1226
1227 acpi_walk_err:
1228         complete(&probe_event);
1229         if (ret_val)
1230                 vmbus_acpi_remove(device);
1231         return ret_val;
1232 }
1233
1234 static const struct acpi_device_id vmbus_acpi_device_ids[] = {
1235         {"VMBUS", 0},
1236         {"VMBus", 0},
1237         {"", 0},
1238 };
1239 MODULE_DEVICE_TABLE(acpi, vmbus_acpi_device_ids);
1240
1241 static struct acpi_driver vmbus_acpi_driver = {
1242         .name = "vmbus",
1243         .ids = vmbus_acpi_device_ids,
1244         .ops = {
1245                 .add = vmbus_acpi_add,
1246                 .remove = vmbus_acpi_remove,
1247         },
1248 };
1249
1250 static void hv_kexec_handler(void)
1251 {
1252         int cpu;
1253
1254         hv_synic_clockevents_cleanup();
1255         vmbus_initiate_unload(false);
1256         for_each_online_cpu(cpu)
1257                 smp_call_function_single(cpu, hv_synic_cleanup, NULL, 1);
1258         hv_cleanup();
1259 };
1260
1261 static void hv_crash_handler(struct pt_regs *regs)
1262 {
1263         vmbus_initiate_unload(true);
1264         /*
1265          * In crash handler we can't schedule synic cleanup for all CPUs,
1266          * doing the cleanup for current CPU only. This should be sufficient
1267          * for kdump.
1268          */
1269         hv_synic_cleanup(NULL);
1270         hv_cleanup();
1271 };
1272
1273 static int __init hv_acpi_init(void)
1274 {
1275         int ret, t;
1276
1277         if (x86_hyper != &x86_hyper_ms_hyperv)
1278                 return -ENODEV;
1279
1280         init_completion(&probe_event);
1281
1282         /*
1283          * Get ACPI resources first.
1284          */
1285         ret = acpi_bus_register_driver(&vmbus_acpi_driver);
1286
1287         if (ret)
1288                 return ret;
1289
1290         t = wait_for_completion_timeout(&probe_event, 5*HZ);
1291         if (t == 0) {
1292                 ret = -ETIMEDOUT;
1293                 goto cleanup;
1294         }
1295
1296         ret = vmbus_bus_init();
1297         if (ret)
1298                 goto cleanup;
1299
1300         hv_setup_kexec_handler(hv_kexec_handler);
1301         hv_setup_crash_handler(hv_crash_handler);
1302
1303         return 0;
1304
1305 cleanup:
1306         acpi_bus_unregister_driver(&vmbus_acpi_driver);
1307         hv_acpi_dev = NULL;
1308         return ret;
1309 }
1310
1311 static void __exit vmbus_exit(void)
1312 {
1313         int cpu;
1314
1315         hv_remove_kexec_handler();
1316         hv_remove_crash_handler();
1317         vmbus_connection.conn_state = DISCONNECTED;
1318         hv_synic_clockevents_cleanup();
1319         vmbus_disconnect();
1320         hv_remove_vmbus_irq();
1321         for_each_online_cpu(cpu)
1322                 tasklet_kill(hv_context.msg_dpc[cpu]);
1323         vmbus_free_channels();
1324         if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
1325                 unregister_die_notifier(&hyperv_die_block);
1326                 atomic_notifier_chain_unregister(&panic_notifier_list,
1327                                                  &hyperv_panic_block);
1328         }
1329         bus_unregister(&hv_bus);
1330         hv_cleanup();
1331         for_each_online_cpu(cpu) {
1332                 tasklet_kill(hv_context.event_dpc[cpu]);
1333                 smp_call_function_single(cpu, hv_synic_cleanup, NULL, 1);
1334         }
1335         hv_synic_free();
1336         acpi_bus_unregister_driver(&vmbus_acpi_driver);
1337         if (vmbus_proto_version > VERSION_WIN7)
1338                 cpu_hotplug_enable();
1339 }
1340
1341
1342 MODULE_LICENSE("GPL");
1343
1344 subsys_initcall(hv_acpi_init);
1345 module_exit(vmbus_exit);