kernel/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 "hyperv_vmbus.h"
  43
  44 static struct acpi_device  *hv_acpi_dev;
  45
  46 static struct tasklet_struct msg_dpc;
  47 static struct completion probe_event;
  48 static int irq;
  49
  50
  51 static int hyperv_panic_event(struct notifier_block *nb,
  52                         unsigned long event, void *ptr)
  53 {
  54         struct pt_regs *regs;
  55
  56         regs = current_pt_regs();
  57
  58         wrmsrl(HV_X64_MSR_CRASH_P0, regs->ip);
  59         wrmsrl(HV_X64_MSR_CRASH_P1, regs->ax);
  60         wrmsrl(HV_X64_MSR_CRASH_P2, regs->bx);
  61         wrmsrl(HV_X64_MSR_CRASH_P3, regs->cx);
  62         wrmsrl(HV_X64_MSR_CRASH_P4, regs->dx);
  63
  64         /*
  65          * Let Hyper-V know there is crash data available
  66          */
  67         wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
  68         return NOTIFY_DONE;
  69 }
  70
  71 static struct notifier_block hyperv_panic_block = {
  72         .notifier_call = hyperv_panic_event,
  73 };
  74
  75 struct resource hyperv_mmio = {
  76         .name  = "hyperv mmio",
  77         .flags = IORESOURCE_MEM,
  78 };
  79 EXPORT_SYMBOL_GPL(hyperv_mmio);
  80
  81 static int vmbus_exists(void)
  82 {
  83         if (hv_acpi_dev == NULL)
  84                 return -ENODEV;
  85
  86         return 0;
  87 }
  88
  89 #define VMBUS_ALIAS_LEN ((sizeof((struct hv_vmbus_device_id *)0)->guid) * 2)
  90 static void print_alias_name(struct hv_device *hv_dev, char *alias_name)
  91 {
  92         int i;
  93         for (i = 0; i < VMBUS_ALIAS_LEN; i += 2)
  94                 sprintf(&alias_name[i], "%02x", hv_dev->dev_type.b[i/2]);
  95 }
  96
  97 static u8 channel_monitor_group(struct vmbus_channel *channel)
  98 {
  99         return (u8)channel->offermsg.monitorid / 32;
 100 }
 101
 102 static u8 channel_monitor_offset(struct vmbus_channel *channel)
 103 {
 104         return (u8)channel->offermsg.monitorid % 32;
 105 }
 106
 107 static u32 channel_pending(struct vmbus_channel *channel,
 108                            struct hv_monitor_page *monitor_page)
 109 {
 110         u8 monitor_group = channel_monitor_group(channel);
 111         return monitor_page->trigger_group[monitor_group].pending;
 112 }
 113
 114 static u32 channel_latency(struct vmbus_channel *channel,
 115                            struct hv_monitor_page *monitor_page)
 116 {
 117         u8 monitor_group = channel_monitor_group(channel);
 118         u8 monitor_offset = channel_monitor_offset(channel);
 119         return monitor_page->latency[monitor_group][monitor_offset];
 120 }
 121
 122 static u32 channel_conn_id(struct vmbus_channel *channel,
 123                            struct hv_monitor_page *monitor_page)
 124 {
 125         u8 monitor_group = channel_monitor_group(channel);
 126         u8 monitor_offset = channel_monitor_offset(channel);
 127         return monitor_page->parameter[monitor_group][monitor_offset].connectionid.u.id;
 128 }
 129
 130 static ssize_t id_show(struct device *dev, struct device_attribute *dev_attr,
 131                        char *buf)
 132 {
 133         struct hv_device *hv_dev = device_to_hv_device(dev);
 134
 135         if (!hv_dev->channel)
 136                 return -ENODEV;
 137         return sprintf(buf, "%d\n", hv_dev->channel->offermsg.child_relid);
 138 }
 139 static DEVICE_ATTR_RO(id);
 140
 141 static ssize_t state_show(struct device *dev, struct device_attribute *dev_attr,
 142                           char *buf)
 143 {
 144         struct hv_device *hv_dev = device_to_hv_device(dev);
 145
 146         if (!hv_dev->channel)
 147                 return -ENODEV;
 148         return sprintf(buf, "%d\n", hv_dev->channel->state);
 149 }
 150 static DEVICE_ATTR_RO(state);
 151
 152 static ssize_t monitor_id_show(struct device *dev,
 153                                struct device_attribute *dev_attr, char *buf)
 154 {
 155         struct hv_device *hv_dev = device_to_hv_device(dev);
 156
 157         if (!hv_dev->channel)
 158                 return -ENODEV;
 159         return sprintf(buf, "%d\n", hv_dev->channel->offermsg.monitorid);
 160 }
 161 static DEVICE_ATTR_RO(monitor_id);
 162
 163 static ssize_t class_id_show(struct device *dev,
 164                                struct device_attribute *dev_attr, char *buf)
 165 {
 166         struct hv_device *hv_dev = device_to_hv_device(dev);
 167
 168         if (!hv_dev->channel)
 169                 return -ENODEV;
 170         return sprintf(buf, "{%pUl}\n",
 171                        hv_dev->channel->offermsg.offer.if_type.b);
 172 }
 173 static DEVICE_ATTR_RO(class_id);
 174
 175 static ssize_t device_id_show(struct device *dev,
 176                               struct device_attribute *dev_attr, char *buf)
 177 {
 178         struct hv_device *hv_dev = device_to_hv_device(dev);
 179
 180         if (!hv_dev->channel)
 181                 return -ENODEV;
 182         return sprintf(buf, "{%pUl}\n",
 183                        hv_dev->channel->offermsg.offer.if_instance.b);
 184 }
 185 static DEVICE_ATTR_RO(device_id);
 186
 187 static ssize_t modalias_show(struct device *dev,
 188                              struct device_attribute *dev_attr, char *buf)
 189 {
 190         struct hv_device *hv_dev = device_to_hv_device(dev);
 191         char alias_name[VMBUS_ALIAS_LEN + 1];
 192
 193         print_alias_name(hv_dev, alias_name);
 194         return sprintf(buf, "vmbus:%s\n", alias_name);
 195 }
 196 static DEVICE_ATTR_RO(modalias);
 197
 198 static ssize_t server_monitor_pending_show(struct device *dev,
 199                                            struct device_attribute *dev_attr,
 200                                            char *buf)
 201 {
 202         struct hv_device *hv_dev = device_to_hv_device(dev);
 203
 204         if (!hv_dev->channel)
 205                 return -ENODEV;
 206         return sprintf(buf, "%d\n",
 207                        channel_pending(hv_dev->channel,
 208                                        vmbus_connection.monitor_pages[1]));
 209 }
 210 static DEVICE_ATTR_RO(server_monitor_pending);
 211
 212 static ssize_t client_monitor_pending_show(struct device *dev,
 213                                            struct device_attribute *dev_attr,
 214                                            char *buf)
 215 {
 216         struct hv_device *hv_dev = device_to_hv_device(dev);
 217
 218         if (!hv_dev->channel)
 219                 return -ENODEV;
 220         return sprintf(buf, "%d\n",
 221                        channel_pending(hv_dev->channel,
 222                                        vmbus_connection.monitor_pages[1]));
 223 }
 224 static DEVICE_ATTR_RO(client_monitor_pending);
 225
 226 static ssize_t server_monitor_latency_show(struct device *dev,
 227                                            struct device_attribute *dev_attr,
 228                                            char *buf)
 229 {
 230         struct hv_device *hv_dev = device_to_hv_device(dev);
 231
 232         if (!hv_dev->channel)
 233                 return -ENODEV;
 234         return sprintf(buf, "%d\n",
 235                        channel_latency(hv_dev->channel,
 236                                        vmbus_connection.monitor_pages[0]));
 237 }
 238 static DEVICE_ATTR_RO(server_monitor_latency);
 239
 240 static ssize_t client_monitor_latency_show(struct device *dev,
 241                                            struct device_attribute *dev_attr,
 242                                            char *buf)
 243 {
 244         struct hv_device *hv_dev = device_to_hv_device(dev);
 245
 246         if (!hv_dev->channel)
 247                 return -ENODEV;
 248         return sprintf(buf, "%d\n",
 249                        channel_latency(hv_dev->channel,
 250                                        vmbus_connection.monitor_pages[1]));
 251 }
 252 static DEVICE_ATTR_RO(client_monitor_latency);
 253
 254 static ssize_t server_monitor_conn_id_show(struct device *dev,
 255                                            struct device_attribute *dev_attr,
 256                                            char *buf)
 257 {
 258         struct hv_device *hv_dev = device_to_hv_device(dev);
 259
 260         if (!hv_dev->channel)
 261                 return -ENODEV;
 262         return sprintf(buf, "%d\n",
 263                        channel_conn_id(hv_dev->channel,
 264                                        vmbus_connection.monitor_pages[0]));
 265 }
 266 static DEVICE_ATTR_RO(server_monitor_conn_id);
 267
 268 static ssize_t client_monitor_conn_id_show(struct device *dev,
 269                                            struct device_attribute *dev_attr,
 270                                            char *buf)
 271 {
 272         struct hv_device *hv_dev = device_to_hv_device(dev);
 273
 274         if (!hv_dev->channel)
 275                 return -ENODEV;
 276         return sprintf(buf, "%d\n",
 277                        channel_conn_id(hv_dev->channel,
 278                                        vmbus_connection.monitor_pages[1]));
 279 }
 280 static DEVICE_ATTR_RO(client_monitor_conn_id);
 281
 282 static ssize_t out_intr_mask_show(struct device *dev,
 283                                   struct device_attribute *dev_attr, char *buf)
 284 {
 285         struct hv_device *hv_dev = device_to_hv_device(dev);
 286         struct hv_ring_buffer_debug_info outbound;
 287
 288         if (!hv_dev->channel)
 289                 return -ENODEV;
 290         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 291         return sprintf(buf, "%d\n", outbound.current_interrupt_mask);
 292 }
 293 static DEVICE_ATTR_RO(out_intr_mask);
 294
 295 static ssize_t out_read_index_show(struct device *dev,
 296                                    struct device_attribute *dev_attr, char *buf)
 297 {
 298         struct hv_device *hv_dev = device_to_hv_device(dev);
 299         struct hv_ring_buffer_debug_info outbound;
 300
 301         if (!hv_dev->channel)
 302                 return -ENODEV;
 303         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 304         return sprintf(buf, "%d\n", outbound.current_read_index);
 305 }
 306 static DEVICE_ATTR_RO(out_read_index);
 307
 308 static ssize_t out_write_index_show(struct device *dev,
 309                                     struct device_attribute *dev_attr,
 310                                     char *buf)
 311 {
 312         struct hv_device *hv_dev = device_to_hv_device(dev);
 313         struct hv_ring_buffer_debug_info outbound;
 314
 315         if (!hv_dev->channel)
 316                 return -ENODEV;
 317         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 318         return sprintf(buf, "%d\n", outbound.current_write_index);
 319 }
 320 static DEVICE_ATTR_RO(out_write_index);
 321
 322 static ssize_t out_read_bytes_avail_show(struct device *dev,
 323                                          struct device_attribute *dev_attr,
 324                                          char *buf)
 325 {
 326         struct hv_device *hv_dev = device_to_hv_device(dev);
 327         struct hv_ring_buffer_debug_info outbound;
 328
 329         if (!hv_dev->channel)
 330                 return -ENODEV;
 331         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 332         return sprintf(buf, "%d\n", outbound.bytes_avail_toread);
 333 }
 334 static DEVICE_ATTR_RO(out_read_bytes_avail);
 335
 336 static ssize_t out_write_bytes_avail_show(struct device *dev,
 337                                           struct device_attribute *dev_attr,
 338                                           char *buf)
 339 {
 340         struct hv_device *hv_dev = device_to_hv_device(dev);
 341         struct hv_ring_buffer_debug_info outbound;
 342
 343         if (!hv_dev->channel)
 344                 return -ENODEV;
 345         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 346         return sprintf(buf, "%d\n", outbound.bytes_avail_towrite);
 347 }
 348 static DEVICE_ATTR_RO(out_write_bytes_avail);
 349
 350 static ssize_t in_intr_mask_show(struct device *dev,
 351                                  struct device_attribute *dev_attr, char *buf)
 352 {
 353         struct hv_device *hv_dev = device_to_hv_device(dev);
 354         struct hv_ring_buffer_debug_info inbound;
 355
 356         if (!hv_dev->channel)
 357                 return -ENODEV;
 358         hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 359         return sprintf(buf, "%d\n", inbound.current_interrupt_mask);
 360 }
 361 static DEVICE_ATTR_RO(in_intr_mask);
 362
 363 static ssize_t in_read_index_show(struct device *dev,
 364                                   struct device_attribute *dev_attr, char *buf)
 365 {
 366         struct hv_device *hv_dev = device_to_hv_device(dev);
 367         struct hv_ring_buffer_debug_info inbound;
 368
 369         if (!hv_dev->channel)
 370                 return -ENODEV;
 371         hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 372         return sprintf(buf, "%d\n", inbound.current_read_index);
 373 }
 374 static DEVICE_ATTR_RO(in_read_index);
 375
 376 static ssize_t in_write_index_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_write_index);
 386 }
 387 static DEVICE_ATTR_RO(in_write_index);
 388
 389 static ssize_t in_read_bytes_avail_show(struct device *dev,
 390                                         struct device_attribute *dev_attr,
 391                                         char *buf)
 392 {
 393         struct hv_device *hv_dev = device_to_hv_device(dev);
 394         struct hv_ring_buffer_debug_info inbound;
 395
 396         if (!hv_dev->channel)
 397                 return -ENODEV;
 398         hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 399         return sprintf(buf, "%d\n", inbound.bytes_avail_toread);
 400 }
 401 static DEVICE_ATTR_RO(in_read_bytes_avail);
 402
 403 static ssize_t in_write_bytes_avail_show(struct device *dev,
 404                                          struct device_attribute *dev_attr,
 405                                          char *buf)
 406 {
 407         struct hv_device *hv_dev = device_to_hv_device(dev);
 408         struct hv_ring_buffer_debug_info inbound;
 409
 410         if (!hv_dev->channel)
 411                 return -ENODEV;
 412         hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 413         return sprintf(buf, "%d\n", inbound.bytes_avail_towrite);
 414 }
 415 static DEVICE_ATTR_RO(in_write_bytes_avail);
 416
 417 /* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
 418 static struct attribute *vmbus_attrs[] = {
 419         &dev_attr_id.attr,
 420         &dev_attr_state.attr,
 421         &dev_attr_monitor_id.attr,
 422         &dev_attr_class_id.attr,
 423         &dev_attr_device_id.attr,
 424         &dev_attr_modalias.attr,
 425         &dev_attr_server_monitor_pending.attr,
 426         &dev_attr_client_monitor_pending.attr,
 427         &dev_attr_server_monitor_latency.attr,
 428         &dev_attr_client_monitor_latency.attr,
 429         &dev_attr_server_monitor_conn_id.attr,
 430         &dev_attr_client_monitor_conn_id.attr,
 431         &dev_attr_out_intr_mask.attr,
 432         &dev_attr_out_read_index.attr,
 433         &dev_attr_out_write_index.attr,
 434         &dev_attr_out_read_bytes_avail.attr,
 435         &dev_attr_out_write_bytes_avail.attr,
 436         &dev_attr_in_intr_mask.attr,
 437         &dev_attr_in_read_index.attr,
 438         &dev_attr_in_write_index.attr,
 439         &dev_attr_in_read_bytes_avail.attr,
 440         &dev_attr_in_write_bytes_avail.attr,
 441         NULL,
 442 };
 443 ATTRIBUTE_GROUPS(vmbus);
 444
 445 /*
 446  * vmbus_uevent - add uevent for our device
 447  *
 448  * This routine is invoked when a device is added or removed on the vmbus to
 449  * generate a uevent to udev in the userspace. The udev will then look at its
 450  * rule and the uevent generated here to load the appropriate driver
 451  *
 452  * The alias string will be of the form vmbus:guid where guid is the string
 453  * representation of the device guid (each byte of the guid will be
 454  * represented with two hex characters.
 455  */
 456 static int vmbus_uevent(struct device *device, struct kobj_uevent_env *env)
 457 {
 458         struct hv_device *dev = device_to_hv_device(device);
 459         int ret;
 460         char alias_name[VMBUS_ALIAS_LEN + 1];
 461
 462         print_alias_name(dev, alias_name);
 463         ret = add_uevent_var(env, "MODALIAS=vmbus:%s", alias_name);
 464         return ret;
 465 }
 466
 467 static const uuid_le null_guid;
 468
 469 static inline bool is_null_guid(const __u8 *guid)
 470 {
 471         if (memcmp(guid, &null_guid, sizeof(uuid_le)))
 472                 return false;
 473         return true;
 474 }
 475
 476 /*
 477  * Return a matching hv_vmbus_device_id pointer.
 478  * If there is no match, return NULL.
 479  */
 480 static const struct hv_vmbus_device_id *hv_vmbus_get_id(
 481                                         const struct hv_vmbus_device_id *id,
 482                                         const __u8 *guid)
 483 {
 484         for (; !is_null_guid(id->guid); id++)
 485                 if (!memcmp(&id->guid, guid, sizeof(uuid_le)))
 486                         return id;
 487
 488         return NULL;
 489 }
 490
 491
 492
 493 /*
 494  * vmbus_match - Attempt to match the specified device to the specified driver
 495  */
 496 static int vmbus_match(struct device *device, struct device_driver *driver)
 497 {
 498         struct hv_driver *drv = drv_to_hv_drv(driver);
 499         struct hv_device *hv_dev = device_to_hv_device(device);
 500
 501         if (hv_vmbus_get_id(drv->id_table, hv_dev->dev_type.b))
 502                 return 1;
 503
 504         return 0;
 505 }
 506
 507 /*
 508  * vmbus_probe - Add the new vmbus's child device
 509  */
 510 static int vmbus_probe(struct device *child_device)
 511 {
 512         int ret = 0;
 513         struct hv_driver *drv =
 514                         drv_to_hv_drv(child_device->driver);
 515         struct hv_device *dev = device_to_hv_device(child_device);
 516         const struct hv_vmbus_device_id *dev_id;
 517
 518         dev_id = hv_vmbus_get_id(drv->id_table, dev->dev_type.b);
 519         if (drv->probe) {
 520                 ret = drv->probe(dev, dev_id);
 521                 if (ret != 0)
 522                         pr_err("probe failed for device %s (%d)\n",
 523                                dev_name(child_device), ret);
 524
 525         } else {
 526                 pr_err("probe not set for driver %s\n",
 527                        dev_name(child_device));
 528                 ret = -ENODEV;
 529         }
 530         return ret;
 531 }
 532
 533 /*
 534  * vmbus_remove - Remove a vmbus device
 535  */
 536 static int vmbus_remove(struct device *child_device)
 537 {
 538         struct hv_driver *drv;
 539         struct hv_device *dev = device_to_hv_device(child_device);
 540         u32 relid = dev->channel->offermsg.child_relid;
 541
 542         if (child_device->driver) {
 543                 drv = drv_to_hv_drv(child_device->driver);
 544                 if (drv->remove)
 545                         drv->remove(dev);
 546                 else {
 547                         hv_process_channel_removal(dev->channel, relid);
 548                         pr_err("remove not set for driver %s\n",
 549                                 dev_name(child_device));
 550                 }
 551         } else {
 552                 /*
 553                  * We don't have a driver for this device; deal with the
 554                  * rescind message by removing the channel.
 555                  */
 556                 hv_process_channel_removal(dev->channel, relid);
 557         }
 558
 559         return 0;
 560 }
 561
 562
 563 /*
 564  * vmbus_shutdown - Shutdown a vmbus device
 565  */
 566 static void vmbus_shutdown(struct device *child_device)
 567 {
 568         struct hv_driver *drv;
 569         struct hv_device *dev = device_to_hv_device(child_device);
 570
 571
 572         /* The device may not be attached yet */
 573         if (!child_device->driver)
 574                 return;
 575
 576         drv = drv_to_hv_drv(child_device->driver);
 577
 578         if (drv->shutdown)
 579                 drv->shutdown(dev);
 580
 581         return;
 582 }
 583
 584
 585 /*
 586  * vmbus_device_release - Final callback release of the vmbus child device
 587  */
 588 static void vmbus_device_release(struct device *device)
 589 {
 590         struct hv_device *hv_dev = device_to_hv_device(device);
 591
 592         kfree(hv_dev);
 593
 594 }
 595
 596 /* The one and only one */
 597 static struct bus_type  hv_bus = {
 598         .name =         "vmbus",
 599         .match =                vmbus_match,
 600         .shutdown =             vmbus_shutdown,
 601         .remove =               vmbus_remove,
 602         .probe =                vmbus_probe,
 603         .uevent =               vmbus_uevent,
 604         .dev_groups =           vmbus_groups,
 605 };
 606
 607 struct onmessage_work_context {
 608         struct work_struct work;
 609         struct hv_message msg;
 610 };
 611
 612 static void vmbus_onmessage_work(struct work_struct *work)
 613 {
 614         struct onmessage_work_context *ctx;
 615
 616         /* Do not process messages if we're in DISCONNECTED state */
 617         if (vmbus_connection.conn_state == DISCONNECTED)
 618                 return;
 619
 620         ctx = container_of(work, struct onmessage_work_context,
 621                            work);
 622         vmbus_onmessage(&ctx->msg);
 623         kfree(ctx);
 624 }
 625
 626 static void hv_process_timer_expiration(struct hv_message *msg, int cpu)
 627 {
 628         struct clock_event_device *dev = hv_context.clk_evt[cpu];
 629
 630         if (dev->event_handler)
 631                 dev->event_handler(dev);
 632
 633         msg->header.message_type = HVMSG_NONE;
 634
 635         /*
 636          * Make sure the write to MessageType (ie set to
 637          * HVMSG_NONE) happens before we read the
 638          * MessagePending and EOMing. Otherwise, the EOMing
 639          * will not deliver any more messages since there is
 640          * no empty slot
 641          */
 642         mb();
 643
 644         if (msg->header.message_flags.msg_pending) {
 645                 /*
 646                  * This will cause message queue rescan to
 647                  * possibly deliver another msg from the
 648                  * hypervisor
 649                  */
 650                 wrmsrl(HV_X64_MSR_EOM, 0);
 651         }
 652 }
 653
 654 static void vmbus_on_msg_dpc(unsigned long data)
 655 {
 656         int cpu = smp_processor_id();
 657         void *page_addr = hv_context.synic_message_page[cpu];
 658         struct hv_message *msg = (struct hv_message *)page_addr +
 659                                   VMBUS_MESSAGE_SINT;
 660         struct vmbus_channel_message_header *hdr;
 661         struct vmbus_channel_message_table_entry *entry;
 662         struct onmessage_work_context *ctx;
 663
 664         while (1) {
 665                 if (msg->header.message_type == HVMSG_NONE)
 666                         /* no msg */
 667                         break;
 668
 669                 hdr = (struct vmbus_channel_message_header *)msg->u.payload;
 670
 671                 if (hdr->msgtype >= CHANNELMSG_COUNT) {
 672                         WARN_ONCE(1, "unknown msgtype=%d\n", hdr->msgtype);
 673                         goto msg_handled;
 674                 }
 675
 676                 entry = &channel_message_table[hdr->msgtype];
 677                 if (entry->handler_type == VMHT_BLOCKING) {
 678                         ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC);
 679                         if (ctx == NULL)
 680                                 continue;
 681
 682                         INIT_WORK(&ctx->work, vmbus_onmessage_work);
 683                         memcpy(&ctx->msg, msg, sizeof(*msg));
 684
 685                         queue_work(vmbus_connection.work_queue, &ctx->work);
 686                 } else
 687                         entry->message_handler(hdr);
 688
 689 msg_handled:
 690                 msg->header.message_type = HVMSG_NONE;
 691
 692                 /*
 693                  * Make sure the write to MessageType (ie set to
 694                  * HVMSG_NONE) happens before we read the
 695                  * MessagePending and EOMing. Otherwise, the EOMing
 696                  * will not deliver any more messages since there is
 697                  * no empty slot
 698                  */
 699                 mb();
 700
 701                 if (msg->header.message_flags.msg_pending) {
 702                         /*
 703                          * This will cause message queue rescan to
 704                          * possibly deliver another msg from the
 705                          * hypervisor
 706                          */
 707                         wrmsrl(HV_X64_MSR_EOM, 0);
 708                 }
 709         }
 710 }
 711
 712 static void vmbus_isr(void)
 713 {
 714         int cpu = smp_processor_id();
 715         void *page_addr;
 716         struct hv_message *msg;
 717         union hv_synic_event_flags *event;
 718         bool handled = false;
 719
 720         page_addr = hv_context.synic_event_page[cpu];
 721         if (page_addr == NULL)
 722                 return;
 723
 724         event = (union hv_synic_event_flags *)page_addr +
 725                                          VMBUS_MESSAGE_SINT;
 726         /*
 727          * Check for events before checking for messages. This is the order
 728          * in which events and messages are checked in Windows guests on
 729          * Hyper-V, and the Windows team suggested we do the same.
 730          */
 731
 732         if ((vmbus_proto_version == VERSION_WS2008) ||
 733                 (vmbus_proto_version == VERSION_WIN7)) {
 734
 735                 /* Since we are a child, we only need to check bit 0 */
 736                 if (sync_test_and_clear_bit(0,
 737                         (unsigned long *) &event->flags32[0])) {
 738                         handled = true;
 739                 }
 740         } else {
 741                 /*
 742                  * Our host is win8 or above. The signaling mechanism
 743                  * has changed and we can directly look at the event page.
 744                  * If bit n is set then we have an interrup on the channel
 745                  * whose id is n.
 746                  */
 747                 handled = true;
 748         }
 749
 750         if (handled)
 751                 tasklet_schedule(hv_context.event_dpc[cpu]);
 752
 753
 754         page_addr = hv_context.synic_message_page[cpu];
 755         msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
 756
 757         /* Check if there are actual msgs to be processed */
 758         if (msg->header.message_type != HVMSG_NONE) {
 759                 if (msg->header.message_type == HVMSG_TIMER_EXPIRED)
 760                         hv_process_timer_expiration(msg, cpu);
 761                 else
 762                         tasklet_schedule(&msg_dpc);
 763         }
 764 }
 765
 766 #ifdef CONFIG_HOTPLUG_CPU
 767 static int hyperv_cpu_disable(void)
 768 {
 769         return -ENOSYS;
 770 }
 771
 772 static void hv_cpu_hotplug_quirk(bool vmbus_loaded)
 773 {
 774         static void *previous_cpu_disable;
 775
 776         /*
 777          * Offlining a CPU when running on newer hypervisors (WS2012R2, Win8,
 778          * ...) is not supported at this moment as channel interrupts are
 779          * distributed across all of them.
 780          */
 781
 782         if ((vmbus_proto_version == VERSION_WS2008) ||
 783             (vmbus_proto_version == VERSION_WIN7))
 784                 return;
 785
 786         if (vmbus_loaded) {
 787                 previous_cpu_disable = smp_ops.cpu_disable;
 788                 smp_ops.cpu_disable = hyperv_cpu_disable;
 789                 pr_notice("CPU offlining is not supported by hypervisor\n");
 790         } else if (previous_cpu_disable)
 791                 smp_ops.cpu_disable = previous_cpu_disable;
 792 }
 793 #else
 794 static void hv_cpu_hotplug_quirk(bool vmbus_loaded)
 795 {
 796 }
 797 #endif
 798
 799 /*
 800  * vmbus_bus_init -Main vmbus driver initialization routine.
 801  *
 802  * Here, we
 803  *      - initialize the vmbus driver context
 804  *      - invoke the vmbus hv main init routine
 805  *      - get the irq resource
 806  *      - retrieve the channel offers
 807  */
 808 static int vmbus_bus_init(int irq)
 809 {
 810         int ret;
 811
 812         /* Hypervisor initialization...setup hypercall page..etc */
 813         ret = hv_init();
 814         if (ret != 0) {
 815                 pr_err("Unable to initialize the hypervisor - 0x%x\n", ret);
 816                 return ret;
 817         }
 818
 819         tasklet_init(&msg_dpc, vmbus_on_msg_dpc, 0);
 820
 821         ret = bus_register(&hv_bus);
 822         if (ret)
 823                 goto err_cleanup;
 824
 825         hv_setup_vmbus_irq(vmbus_isr);
 826
 827         ret = hv_synic_alloc();
 828         if (ret)
 829                 goto err_alloc;
 830         /*
 831          * Initialize the per-cpu interrupt state and
 832          * connect to the host.
 833          */
 834         on_each_cpu(hv_synic_init, NULL, 1);
 835         ret = vmbus_connect();
 836         if (ret)
 837                 goto err_alloc;
 838
 839         hv_cpu_hotplug_quirk(true);
 840
 841         /*
 842          * Only register if the crash MSRs are available
 843          */
 844         if (ms_hyperv.features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
 845                 atomic_notifier_chain_register(&panic_notifier_list,
 846                                                &hyperv_panic_block);
 847         }
 848
 849         vmbus_request_offers();
 850
 851         return 0;
 852
 853 err_alloc:
 854         hv_synic_free();
 855         hv_remove_vmbus_irq();
 856
 857         bus_unregister(&hv_bus);
 858
 859 err_cleanup:
 860         hv_cleanup();
 861
 862         return ret;
 863 }
 864
 865 /**
 866  * __vmbus_child_driver_register - Register a vmbus's driver
 867  * @drv: Pointer to driver structure you want to register
 868  * @owner: owner module of the drv
 869  * @mod_name: module name string
 870  *
 871  * Registers the given driver with Linux through the 'driver_register()' call
 872  * and sets up the hyper-v vmbus handling for this driver.
 873  * It will return the state of the 'driver_register()' call.
 874  *
 875  */
 876 int __vmbus_driver_register(struct hv_driver *hv_driver, struct module *owner, const char *mod_name)
 877 {
 878         int ret;
 879
 880         pr_info("registering driver %s\n", hv_driver->name);
 881
 882         ret = vmbus_exists();
 883         if (ret < 0)
 884                 return ret;
 885
 886         hv_driver->driver.name = hv_driver->name;
 887         hv_driver->driver.owner = owner;
 888         hv_driver->driver.mod_name = mod_name;
 889         hv_driver->driver.bus = &hv_bus;
 890
 891         ret = driver_register(&hv_driver->driver);
 892
 893         return ret;
 894 }
 895 EXPORT_SYMBOL_GPL(__vmbus_driver_register);
 896
 897 /**
 898  * vmbus_driver_unregister() - Unregister a vmbus's driver
 899  * @drv: Pointer to driver structure you want to un-register
 900  *
 901  * Un-register the given driver that was previous registered with a call to
 902  * vmbus_driver_register()
 903  */
 904 void vmbus_driver_unregister(struct hv_driver *hv_driver)
 905 {
 906         pr_info("unregistering driver %s\n", hv_driver->name);
 907
 908         if (!vmbus_exists())
 909                 driver_unregister(&hv_driver->driver);
 910 }
 911 EXPORT_SYMBOL_GPL(vmbus_driver_unregister);
 912
 913 /*
 914  * vmbus_device_create - Creates and registers a new child device
 915  * on the vmbus.
 916  */
 917 struct hv_device *vmbus_device_create(const uuid_le *type,
 918                                       const uuid_le *instance,
 919                                       struct vmbus_channel *channel)
 920 {
 921         struct hv_device *child_device_obj;
 922
 923         child_device_obj = kzalloc(sizeof(struct hv_device), GFP_KERNEL);
 924         if (!child_device_obj) {
 925                 pr_err("Unable to allocate device object for child device\n");
 926                 return NULL;
 927         }
 928
 929         child_device_obj->channel = channel;
 930         memcpy(&child_device_obj->dev_type, type, sizeof(uuid_le));
 931         memcpy(&child_device_obj->dev_instance, instance,
 932                sizeof(uuid_le));
 933
 934
 935         return child_device_obj;
 936 }
 937
 938 /*
 939  * vmbus_device_register - Register the child device
 940  */
 941 int vmbus_device_register(struct hv_device *child_device_obj)
 942 {
 943         int ret = 0;
 944
 945         dev_set_name(&child_device_obj->device, "vmbus_%d",
 946                      child_device_obj->channel->id);
 947
 948         child_device_obj->device.bus = &hv_bus;
 949         child_device_obj->device.parent = &hv_acpi_dev->dev;
 950         child_device_obj->device.release = vmbus_device_release;
 951
 952         /*
 953          * Register with the LDM. This will kick off the driver/device
 954          * binding...which will eventually call vmbus_match() and vmbus_probe()
 955          */
 956         ret = device_register(&child_device_obj->device);
 957
 958         if (ret)
 959                 pr_err("Unable to register child device\n");
 960         else
 961                 pr_debug("child device %s registered\n",
 962                         dev_name(&child_device_obj->device));
 963
 964         return ret;
 965 }
 966
 967 /*
 968  * vmbus_device_unregister - Remove the specified child device
 969  * from the vmbus.
 970  */
 971 void vmbus_device_unregister(struct hv_device *device_obj)
 972 {
 973         pr_debug("child device %s unregistered\n",
 974                 dev_name(&device_obj->device));
 975
 976         /*
 977          * Kick off the process of unregistering the device.
 978          * This will call vmbus_remove() and eventually vmbus_device_release()
 979          */
 980         device_unregister(&device_obj->device);
 981 }
 982
 983
 984 /*
 985  * VMBUS is an acpi enumerated device. Get the the information we
 986  * need from DSDT.
 987  */
 988
 989 static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *ctx)
 990 {
 991         switch (res->type) {
 992         case ACPI_RESOURCE_TYPE_IRQ:
 993                 irq = res->data.irq.interrupts[0];
 994                 break;
 995
 996         case ACPI_RESOURCE_TYPE_ADDRESS64:
 997                 hyperv_mmio.start = res->data.address64.address.minimum;
 998                 hyperv_mmio.end = res->data.address64.address.maximum;
 999                 break;
1000         }
1001
1002         return AE_OK;
1003 }
1004
1005 static int vmbus_acpi_add(struct acpi_device *device)
1006 {
1007         acpi_status result;
1008         int ret_val = -ENODEV;
1009
1010         hv_acpi_dev = device;
1011
1012         result = acpi_walk_resources(device->handle, METHOD_NAME__CRS,
1013                                         vmbus_walk_resources, NULL);
1014
1015         if (ACPI_FAILURE(result))
1016                 goto acpi_walk_err;
1017         /*
1018          * The parent of the vmbus acpi device (Gen2 firmware) is the VMOD that
1019          * has the mmio ranges. Get that.
1020          */
1021         if (device->parent) {
1022                 result = acpi_walk_resources(device->parent->handle,
1023                                         METHOD_NAME__CRS,
1024                                         vmbus_walk_resources, NULL);
1025
1026                 if (ACPI_FAILURE(result))
1027                         goto acpi_walk_err;
1028                 if (hyperv_mmio.start && hyperv_mmio.end)
1029                         request_resource(&iomem_resource, &hyperv_mmio);
1030         }
1031         ret_val = 0;
1032
1033 acpi_walk_err:
1034         complete(&probe_event);
1035         return ret_val;
1036 }
1037
1038 static const struct acpi_device_id vmbus_acpi_device_ids[] = {
1039         {"VMBUS", 0},
1040         {"VMBus", 0},
1041         {"", 0},
1042 };
1043 MODULE_DEVICE_TABLE(acpi, vmbus_acpi_device_ids);
1044
1045 static struct acpi_driver vmbus_acpi_driver = {
1046         .name = "vmbus",
1047         .ids = vmbus_acpi_device_ids,
1048         .ops = {
1049                 .add = vmbus_acpi_add,
1050         },
1051 };
1052
1053 static int __init hv_acpi_init(void)
1054 {
1055         int ret, t;
1056
1057         if (x86_hyper != &x86_hyper_ms_hyperv)
1058                 return -ENODEV;
1059
1060         init_completion(&probe_event);
1061
1062         /*
1063          * Get irq resources first.
1064          */
1065         ret = acpi_bus_register_driver(&vmbus_acpi_driver);
1066
1067         if (ret)
1068                 return ret;
1069
1070         t = wait_for_completion_timeout(&probe_event, 5*HZ);
1071         if (t == 0) {
1072                 ret = -ETIMEDOUT;
1073                 goto cleanup;
1074         }
1075
1076         if (irq <= 0) {
1077                 ret = -ENODEV;
1078                 goto cleanup;
1079         }
1080
1081         ret = vmbus_bus_init(irq);
1082         if (ret)
1083                 goto cleanup;
1084
1085         return 0;
1086
1087 cleanup:
1088         acpi_bus_unregister_driver(&vmbus_acpi_driver);
1089         hv_acpi_dev = NULL;
1090         return ret;
1091 }
1092
1093 static void __exit vmbus_exit(void)
1094 {
1095         int cpu;
1096
1097         vmbus_connection.conn_state = DISCONNECTED;
1098         hv_synic_clockevents_cleanup();
1099         hv_remove_vmbus_irq();
1100         vmbus_free_channels();
1101         bus_unregister(&hv_bus);
1102         hv_cleanup();
1103         for_each_online_cpu(cpu)
1104                 smp_call_function_single(cpu, hv_synic_cleanup, NULL, 1);
1105         acpi_bus_unregister_driver(&vmbus_acpi_driver);
1106         hv_cpu_hotplug_quirk(false);
1107         vmbus_disconnect();
1108 }
1109
1110
1111 MODULE_LICENSE("GPL");
1112
1113 subsys_initcall(hv_acpi_init);
1114 module_exit(vmbus_exit);