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/irq.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/sysctl.h>
  31 #include <linux/slab.h>
  32 #include <linux/acpi.h>
  33 #include <linux/completion.h>
  34 #include <linux/hyperv.h>
  35 #include <linux/kernel_stat.h>
  36 #include <asm/hyperv.h>
  37 #include <asm/hypervisor.h>
  38 #include <asm/mshyperv.h>
  39 #include "hyperv_vmbus.h"
  40
  41 static struct acpi_device  *hv_acpi_dev;
  42
  43 static struct tasklet_struct msg_dpc;
  44 static struct completion probe_event;
  45 static int irq;
  46
  47 static int vmbus_exists(void)
  48 {
  49         if (hv_acpi_dev == NULL)
  50                 return -ENODEV;
  51
  52         return 0;
  53 }
  54
  55 #define VMBUS_ALIAS_LEN ((sizeof((struct hv_vmbus_device_id *)0)->guid) * 2)
  56 static void print_alias_name(struct hv_device *hv_dev, char *alias_name)
  57 {
  58         int i;
  59         for (i = 0; i < VMBUS_ALIAS_LEN; i += 2)
  60                 sprintf(&alias_name[i], "%02x", hv_dev->dev_type.b[i/2]);
  61 }
  62
  63 static u8 channel_monitor_group(struct vmbus_channel *channel)
  64 {
  65         return (u8)channel->offermsg.monitorid / 32;
  66 }
  67
  68 static u8 channel_monitor_offset(struct vmbus_channel *channel)
  69 {
  70         return (u8)channel->offermsg.monitorid % 32;
  71 }
  72
  73 static u32 channel_pending(struct vmbus_channel *channel,
  74                            struct hv_monitor_page *monitor_page)
  75 {
  76         u8 monitor_group = channel_monitor_group(channel);
  77         return monitor_page->trigger_group[monitor_group].pending;
  78 }
  79
  80 static u32 channel_latency(struct vmbus_channel *channel,
  81                            struct hv_monitor_page *monitor_page)
  82 {
  83         u8 monitor_group = channel_monitor_group(channel);
  84         u8 monitor_offset = channel_monitor_offset(channel);
  85         return monitor_page->latency[monitor_group][monitor_offset];
  86 }
  87
  88 static u32 channel_conn_id(struct vmbus_channel *channel,
  89                            struct hv_monitor_page *monitor_page)
  90 {
  91         u8 monitor_group = channel_monitor_group(channel);
  92         u8 monitor_offset = channel_monitor_offset(channel);
  93         return monitor_page->parameter[monitor_group][monitor_offset].connectionid.u.id;
  94 }
  95
  96 static ssize_t id_show(struct device *dev, struct device_attribute *dev_attr,
  97                        char *buf)
  98 {
  99         struct hv_device *hv_dev = device_to_hv_device(dev);
 100
 101         if (!hv_dev->channel)
 102                 return -ENODEV;
 103         return sprintf(buf, "%d\n", hv_dev->channel->offermsg.child_relid);
 104 }
 105 static DEVICE_ATTR_RO(id);
 106
 107 static ssize_t state_show(struct device *dev, struct device_attribute *dev_attr,
 108                           char *buf)
 109 {
 110         struct hv_device *hv_dev = device_to_hv_device(dev);
 111
 112         if (!hv_dev->channel)
 113                 return -ENODEV;
 114         return sprintf(buf, "%d\n", hv_dev->channel->state);
 115 }
 116 static DEVICE_ATTR_RO(state);
 117
 118 static ssize_t monitor_id_show(struct device *dev,
 119                                struct device_attribute *dev_attr, char *buf)
 120 {
 121         struct hv_device *hv_dev = device_to_hv_device(dev);
 122
 123         if (!hv_dev->channel)
 124                 return -ENODEV;
 125         return sprintf(buf, "%d\n", hv_dev->channel->offermsg.monitorid);
 126 }
 127 static DEVICE_ATTR_RO(monitor_id);
 128
 129 static ssize_t class_id_show(struct device *dev,
 130                                struct device_attribute *dev_attr, char *buf)
 131 {
 132         struct hv_device *hv_dev = device_to_hv_device(dev);
 133
 134         if (!hv_dev->channel)
 135                 return -ENODEV;
 136         return sprintf(buf, "{%pUl}\n",
 137                        hv_dev->channel->offermsg.offer.if_type.b);
 138 }
 139 static DEVICE_ATTR_RO(class_id);
 140
 141 static ssize_t device_id_show(struct device *dev,
 142                               struct device_attribute *dev_attr, 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, "{%pUl}\n",
 149                        hv_dev->channel->offermsg.offer.if_instance.b);
 150 }
 151 static DEVICE_ATTR_RO(device_id);
 152
 153 static ssize_t modalias_show(struct device *dev,
 154                              struct device_attribute *dev_attr, char *buf)
 155 {
 156         struct hv_device *hv_dev = device_to_hv_device(dev);
 157         char alias_name[VMBUS_ALIAS_LEN + 1];
 158
 159         print_alias_name(hv_dev, alias_name);
 160         return sprintf(buf, "vmbus:%s\n", alias_name);
 161 }
 162 static DEVICE_ATTR_RO(modalias);
 163
 164 static ssize_t server_monitor_pending_show(struct device *dev,
 165                                            struct device_attribute *dev_attr,
 166                                            char *buf)
 167 {
 168         struct hv_device *hv_dev = device_to_hv_device(dev);
 169
 170         if (!hv_dev->channel)
 171                 return -ENODEV;
 172         return sprintf(buf, "%d\n",
 173                        channel_pending(hv_dev->channel,
 174                                        vmbus_connection.monitor_pages[1]));
 175 }
 176 static DEVICE_ATTR_RO(server_monitor_pending);
 177
 178 static ssize_t client_monitor_pending_show(struct device *dev,
 179                                            struct device_attribute *dev_attr,
 180                                            char *buf)
 181 {
 182         struct hv_device *hv_dev = device_to_hv_device(dev);
 183
 184         if (!hv_dev->channel)
 185                 return -ENODEV;
 186         return sprintf(buf, "%d\n",
 187                        channel_pending(hv_dev->channel,
 188                                        vmbus_connection.monitor_pages[1]));
 189 }
 190 static DEVICE_ATTR_RO(client_monitor_pending);
 191
 192 static ssize_t server_monitor_latency_show(struct device *dev,
 193                                            struct device_attribute *dev_attr,
 194                                            char *buf)
 195 {
 196         struct hv_device *hv_dev = device_to_hv_device(dev);
 197
 198         if (!hv_dev->channel)
 199                 return -ENODEV;
 200         return sprintf(buf, "%d\n",
 201                        channel_latency(hv_dev->channel,
 202                                        vmbus_connection.monitor_pages[0]));
 203 }
 204 static DEVICE_ATTR_RO(server_monitor_latency);
 205
 206 static ssize_t client_monitor_latency_show(struct device *dev,
 207                                            struct device_attribute *dev_attr,
 208                                            char *buf)
 209 {
 210         struct hv_device *hv_dev = device_to_hv_device(dev);
 211
 212         if (!hv_dev->channel)
 213                 return -ENODEV;
 214         return sprintf(buf, "%d\n",
 215                        channel_latency(hv_dev->channel,
 216                                        vmbus_connection.monitor_pages[1]));
 217 }
 218 static DEVICE_ATTR_RO(client_monitor_latency);
 219
 220 static ssize_t server_monitor_conn_id_show(struct device *dev,
 221                                            struct device_attribute *dev_attr,
 222                                            char *buf)
 223 {
 224         struct hv_device *hv_dev = device_to_hv_device(dev);
 225
 226         if (!hv_dev->channel)
 227                 return -ENODEV;
 228         return sprintf(buf, "%d\n",
 229                        channel_conn_id(hv_dev->channel,
 230                                        vmbus_connection.monitor_pages[0]));
 231 }
 232 static DEVICE_ATTR_RO(server_monitor_conn_id);
 233
 234 static ssize_t client_monitor_conn_id_show(struct device *dev,
 235                                            struct device_attribute *dev_attr,
 236                                            char *buf)
 237 {
 238         struct hv_device *hv_dev = device_to_hv_device(dev);
 239
 240         if (!hv_dev->channel)
 241                 return -ENODEV;
 242         return sprintf(buf, "%d\n",
 243                        channel_conn_id(hv_dev->channel,
 244                                        vmbus_connection.monitor_pages[1]));
 245 }
 246 static DEVICE_ATTR_RO(client_monitor_conn_id);
 247
 248 static ssize_t out_intr_mask_show(struct device *dev,
 249                                   struct device_attribute *dev_attr, char *buf)
 250 {
 251         struct hv_device *hv_dev = device_to_hv_device(dev);
 252         struct hv_ring_buffer_debug_info outbound;
 253
 254         if (!hv_dev->channel)
 255                 return -ENODEV;
 256         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 257         return sprintf(buf, "%d\n", outbound.current_interrupt_mask);
 258 }
 259 static DEVICE_ATTR_RO(out_intr_mask);
 260
 261 static ssize_t out_read_index_show(struct device *dev,
 262                                    struct device_attribute *dev_attr, char *buf)
 263 {
 264         struct hv_device *hv_dev = device_to_hv_device(dev);
 265         struct hv_ring_buffer_debug_info outbound;
 266
 267         if (!hv_dev->channel)
 268                 return -ENODEV;
 269         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 270         return sprintf(buf, "%d\n", outbound.current_read_index);
 271 }
 272 static DEVICE_ATTR_RO(out_read_index);
 273
 274 static ssize_t out_write_index_show(struct device *dev,
 275                                     struct device_attribute *dev_attr,
 276                                     char *buf)
 277 {
 278         struct hv_device *hv_dev = device_to_hv_device(dev);
 279         struct hv_ring_buffer_debug_info outbound;
 280
 281         if (!hv_dev->channel)
 282                 return -ENODEV;
 283         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 284         return sprintf(buf, "%d\n", outbound.current_write_index);
 285 }
 286 static DEVICE_ATTR_RO(out_write_index);
 287
 288 static ssize_t out_read_bytes_avail_show(struct device *dev,
 289                                          struct device_attribute *dev_attr,
 290                                          char *buf)
 291 {
 292         struct hv_device *hv_dev = device_to_hv_device(dev);
 293         struct hv_ring_buffer_debug_info outbound;
 294
 295         if (!hv_dev->channel)
 296                 return -ENODEV;
 297         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 298         return sprintf(buf, "%d\n", outbound.bytes_avail_toread);
 299 }
 300 static DEVICE_ATTR_RO(out_read_bytes_avail);
 301
 302 static ssize_t out_write_bytes_avail_show(struct device *dev,
 303                                           struct device_attribute *dev_attr,
 304                                           char *buf)
 305 {
 306         struct hv_device *hv_dev = device_to_hv_device(dev);
 307         struct hv_ring_buffer_debug_info outbound;
 308
 309         if (!hv_dev->channel)
 310                 return -ENODEV;
 311         hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 312         return sprintf(buf, "%d\n", outbound.bytes_avail_towrite);
 313 }
 314 static DEVICE_ATTR_RO(out_write_bytes_avail);
 315
 316 static ssize_t in_intr_mask_show(struct device *dev,
 317                                  struct device_attribute *dev_attr, char *buf)
 318 {
 319         struct hv_device *hv_dev = device_to_hv_device(dev);
 320         struct hv_ring_buffer_debug_info inbound;
 321
 322         if (!hv_dev->channel)
 323                 return -ENODEV;
 324         hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 325         return sprintf(buf, "%d\n", inbound.current_interrupt_mask);
 326 }
 327 static DEVICE_ATTR_RO(in_intr_mask);
 328
 329 static ssize_t in_read_index_show(struct device *dev,
 330                                   struct device_attribute *dev_attr, char *buf)
 331 {
 332         struct hv_device *hv_dev = device_to_hv_device(dev);
 333         struct hv_ring_buffer_debug_info inbound;
 334
 335         if (!hv_dev->channel)
 336                 return -ENODEV;
 337         hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 338         return sprintf(buf, "%d\n", inbound.current_read_index);
 339 }
 340 static DEVICE_ATTR_RO(in_read_index);
 341
 342 static ssize_t in_write_index_show(struct device *dev,
 343                                    struct device_attribute *dev_attr, char *buf)
 344 {
 345         struct hv_device *hv_dev = device_to_hv_device(dev);
 346         struct hv_ring_buffer_debug_info inbound;
 347
 348         if (!hv_dev->channel)
 349                 return -ENODEV;
 350         hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 351         return sprintf(buf, "%d\n", inbound.current_write_index);
 352 }
 353 static DEVICE_ATTR_RO(in_write_index);
 354
 355 static ssize_t in_read_bytes_avail_show(struct device *dev,
 356                                         struct device_attribute *dev_attr,
 357                                         char *buf)
 358 {
 359         struct hv_device *hv_dev = device_to_hv_device(dev);
 360         struct hv_ring_buffer_debug_info inbound;
 361
 362         if (!hv_dev->channel)
 363                 return -ENODEV;
 364         hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 365         return sprintf(buf, "%d\n", inbound.bytes_avail_toread);
 366 }
 367 static DEVICE_ATTR_RO(in_read_bytes_avail);
 368
 369 static ssize_t in_write_bytes_avail_show(struct device *dev,
 370                                          struct device_attribute *dev_attr,
 371                                          char *buf)
 372 {
 373         struct hv_device *hv_dev = device_to_hv_device(dev);
 374         struct hv_ring_buffer_debug_info inbound;
 375
 376         if (!hv_dev->channel)
 377                 return -ENODEV;
 378         hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 379         return sprintf(buf, "%d\n", inbound.bytes_avail_towrite);
 380 }
 381 static DEVICE_ATTR_RO(in_write_bytes_avail);
 382
 383 /* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
 384 static struct attribute *vmbus_attrs[] = {
 385         &dev_attr_id.attr,
 386         &dev_attr_state.attr,
 387         &dev_attr_monitor_id.attr,
 388         &dev_attr_class_id.attr,
 389         &dev_attr_device_id.attr,
 390         &dev_attr_modalias.attr,
 391         &dev_attr_server_monitor_pending.attr,
 392         &dev_attr_client_monitor_pending.attr,
 393         &dev_attr_server_monitor_latency.attr,
 394         &dev_attr_client_monitor_latency.attr,
 395         &dev_attr_server_monitor_conn_id.attr,
 396         &dev_attr_client_monitor_conn_id.attr,
 397         &dev_attr_out_intr_mask.attr,
 398         &dev_attr_out_read_index.attr,
 399         &dev_attr_out_write_index.attr,
 400         &dev_attr_out_read_bytes_avail.attr,
 401         &dev_attr_out_write_bytes_avail.attr,
 402         &dev_attr_in_intr_mask.attr,
 403         &dev_attr_in_read_index.attr,
 404         &dev_attr_in_write_index.attr,
 405         &dev_attr_in_read_bytes_avail.attr,
 406         &dev_attr_in_write_bytes_avail.attr,
 407         NULL,
 408 };
 409 ATTRIBUTE_GROUPS(vmbus);
 410
 411 /*
 412  * vmbus_uevent - add uevent for our device
 413  *
 414  * This routine is invoked when a device is added or removed on the vmbus to
 415  * generate a uevent to udev in the userspace. The udev will then look at its
 416  * rule and the uevent generated here to load the appropriate driver
 417  *
 418  * The alias string will be of the form vmbus:guid where guid is the string
 419  * representation of the device guid (each byte of the guid will be
 420  * represented with two hex characters.
 421  */
 422 static int vmbus_uevent(struct device *device, struct kobj_uevent_env *env)
 423 {
 424         struct hv_device *dev = device_to_hv_device(device);
 425         int ret;
 426         char alias_name[VMBUS_ALIAS_LEN + 1];
 427
 428         print_alias_name(dev, alias_name);
 429         ret = add_uevent_var(env, "MODALIAS=vmbus:%s", alias_name);
 430         return ret;
 431 }
 432
 433 static uuid_le null_guid;
 434
 435 static inline bool is_null_guid(const __u8 *guid)
 436 {
 437         if (memcmp(guid, &null_guid, sizeof(uuid_le)))
 438                 return false;
 439         return true;
 440 }
 441
 442 /*
 443  * Return a matching hv_vmbus_device_id pointer.
 444  * If there is no match, return NULL.
 445  */
 446 static const struct hv_vmbus_device_id *hv_vmbus_get_id(
 447                                         const struct hv_vmbus_device_id *id,
 448                                         __u8 *guid)
 449 {
 450         for (; !is_null_guid(id->guid); id++)
 451                 if (!memcmp(&id->guid, guid, sizeof(uuid_le)))
 452                         return id;
 453
 454         return NULL;
 455 }
 456
 457
 458
 459 /*
 460  * vmbus_match - Attempt to match the specified device to the specified driver
 461  */
 462 static int vmbus_match(struct device *device, struct device_driver *driver)
 463 {
 464         struct hv_driver *drv = drv_to_hv_drv(driver);
 465         struct hv_device *hv_dev = device_to_hv_device(device);
 466
 467         if (hv_vmbus_get_id(drv->id_table, hv_dev->dev_type.b))
 468                 return 1;
 469
 470         return 0;
 471 }
 472
 473 /*
 474  * vmbus_probe - Add the new vmbus's child device
 475  */
 476 static int vmbus_probe(struct device *child_device)
 477 {
 478         int ret = 0;
 479         struct hv_driver *drv =
 480                         drv_to_hv_drv(child_device->driver);
 481         struct hv_device *dev = device_to_hv_device(child_device);
 482         const struct hv_vmbus_device_id *dev_id;
 483
 484         dev_id = hv_vmbus_get_id(drv->id_table, dev->dev_type.b);
 485         if (drv->probe) {
 486                 ret = drv->probe(dev, dev_id);
 487                 if (ret != 0)
 488                         pr_err("probe failed for device %s (%d)\n",
 489                                dev_name(child_device), ret);
 490
 491         } else {
 492                 pr_err("probe not set for driver %s\n",
 493                        dev_name(child_device));
 494                 ret = -ENODEV;
 495         }
 496         return ret;
 497 }
 498
 499 /*
 500  * vmbus_remove - Remove a vmbus device
 501  */
 502 static int vmbus_remove(struct device *child_device)
 503 {
 504         struct hv_driver *drv = drv_to_hv_drv(child_device->driver);
 505         struct hv_device *dev = device_to_hv_device(child_device);
 506
 507         if (drv->remove)
 508                 drv->remove(dev);
 509         else
 510                 pr_err("remove not set for driver %s\n",
 511                         dev_name(child_device));
 512
 513         return 0;
 514 }
 515
 516
 517 /*
 518  * vmbus_shutdown - Shutdown a vmbus device
 519  */
 520 static void vmbus_shutdown(struct device *child_device)
 521 {
 522         struct hv_driver *drv;
 523         struct hv_device *dev = device_to_hv_device(child_device);
 524
 525
 526         /* The device may not be attached yet */
 527         if (!child_device->driver)
 528                 return;
 529
 530         drv = drv_to_hv_drv(child_device->driver);
 531
 532         if (drv->shutdown)
 533                 drv->shutdown(dev);
 534
 535         return;
 536 }
 537
 538
 539 /*
 540  * vmbus_device_release - Final callback release of the vmbus child device
 541  */
 542 static void vmbus_device_release(struct device *device)
 543 {
 544         struct hv_device *hv_dev = device_to_hv_device(device);
 545
 546         kfree(hv_dev);
 547
 548 }
 549
 550 /* The one and only one */
 551 static struct bus_type  hv_bus = {
 552         .name =         "vmbus",
 553         .match =                vmbus_match,
 554         .shutdown =             vmbus_shutdown,
 555         .remove =               vmbus_remove,
 556         .probe =                vmbus_probe,
 557         .uevent =               vmbus_uevent,
 558         .dev_groups =           vmbus_groups,
 559 };
 560
 561 static const char *driver_name = "hyperv";
 562
 563
 564 struct onmessage_work_context {
 565         struct work_struct work;
 566         struct hv_message msg;
 567 };
 568
 569 static void vmbus_onmessage_work(struct work_struct *work)
 570 {
 571         struct onmessage_work_context *ctx;
 572
 573         ctx = container_of(work, struct onmessage_work_context,
 574                            work);
 575         vmbus_onmessage(&ctx->msg);
 576         kfree(ctx);
 577 }
 578
 579 static void vmbus_on_msg_dpc(unsigned long data)
 580 {
 581         int cpu = smp_processor_id();
 582         void *page_addr = hv_context.synic_message_page[cpu];
 583         struct hv_message *msg = (struct hv_message *)page_addr +
 584                                   VMBUS_MESSAGE_SINT;
 585         struct onmessage_work_context *ctx;
 586
 587         while (1) {
 588                 if (msg->header.message_type == HVMSG_NONE) {
 589                         /* no msg */
 590                         break;
 591                 } else {
 592                         ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC);
 593                         if (ctx == NULL)
 594                                 continue;
 595                         INIT_WORK(&ctx->work, vmbus_onmessage_work);
 596                         memcpy(&ctx->msg, msg, sizeof(*msg));
 597                         queue_work(vmbus_connection.work_queue, &ctx->work);
 598                 }
 599
 600                 msg->header.message_type = HVMSG_NONE;
 601
 602                 /*
 603                  * Make sure the write to MessageType (ie set to
 604                  * HVMSG_NONE) happens before we read the
 605                  * MessagePending and EOMing. Otherwise, the EOMing
 606                  * will not deliver any more messages since there is
 607                  * no empty slot
 608                  */
 609                 mb();
 610
 611                 if (msg->header.message_flags.msg_pending) {
 612                         /*
 613                          * This will cause message queue rescan to
 614                          * possibly deliver another msg from the
 615                          * hypervisor
 616                          */
 617                         wrmsrl(HV_X64_MSR_EOM, 0);
 618                 }
 619         }
 620 }
 621
 622 static irqreturn_t vmbus_isr(int irq, void *dev_id)
 623 {
 624         int cpu = smp_processor_id();
 625         void *page_addr;
 626         struct hv_message *msg;
 627         union hv_synic_event_flags *event;
 628         bool handled = false;
 629
 630         page_addr = hv_context.synic_event_page[cpu];
 631         if (page_addr == NULL)
 632                 return IRQ_NONE;
 633
 634         event = (union hv_synic_event_flags *)page_addr +
 635                                          VMBUS_MESSAGE_SINT;
 636         /*
 637          * Check for events before checking for messages. This is the order
 638          * in which events and messages are checked in Windows guests on
 639          * Hyper-V, and the Windows team suggested we do the same.
 640          */
 641
 642         if ((vmbus_proto_version == VERSION_WS2008) ||
 643                 (vmbus_proto_version == VERSION_WIN7)) {
 644
 645                 /* Since we are a child, we only need to check bit 0 */
 646                 if (sync_test_and_clear_bit(0,
 647                         (unsigned long *) &event->flags32[0])) {
 648                         handled = true;
 649                 }
 650         } else {
 651                 /*
 652                  * Our host is win8 or above. The signaling mechanism
 653                  * has changed and we can directly look at the event page.
 654                  * If bit n is set then we have an interrup on the channel
 655                  * whose id is n.
 656                  */
 657                 handled = true;
 658         }
 659
 660         if (handled)
 661                 tasklet_schedule(hv_context.event_dpc[cpu]);
 662
 663
 664         page_addr = hv_context.synic_message_page[cpu];
 665         msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
 666
 667         /* Check if there are actual msgs to be processed */
 668         if (msg->header.message_type != HVMSG_NONE) {
 669                 handled = true;
 670                 tasklet_schedule(&msg_dpc);
 671         }
 672
 673         if (handled)
 674                 return IRQ_HANDLED;
 675         else
 676                 return IRQ_NONE;
 677 }
 678
 679 /*
 680  * vmbus interrupt flow handler:
 681  * vmbus interrupts can concurrently occur on multiple CPUs and
 682  * can be handled concurrently.
 683  */
 684
 685 static void vmbus_flow_handler(unsigned int irq, struct irq_desc *desc)
 686 {
 687         kstat_incr_irqs_this_cpu(irq, desc);
 688
 689         desc->action->handler(irq, desc->action->dev_id);
 690 }
 691
 692 /*
 693  * vmbus_bus_init -Main vmbus driver initialization routine.
 694  *
 695  * Here, we
 696  *      - initialize the vmbus driver context
 697  *      - invoke the vmbus hv main init routine
 698  *      - get the irq resource
 699  *      - retrieve the channel offers
 700  */
 701 static int vmbus_bus_init(int irq)
 702 {
 703         int ret;
 704
 705         /* Hypervisor initialization...setup hypercall page..etc */
 706         ret = hv_init();
 707         if (ret != 0) {
 708                 pr_err("Unable to initialize the hypervisor - 0x%x\n", ret);
 709                 return ret;
 710         }
 711
 712         tasklet_init(&msg_dpc, vmbus_on_msg_dpc, 0);
 713
 714         ret = bus_register(&hv_bus);
 715         if (ret)
 716                 goto err_cleanup;
 717
 718         ret = request_irq(irq, vmbus_isr, 0, driver_name, hv_acpi_dev);
 719
 720         if (ret != 0) {
 721                 pr_err("Unable to request IRQ %d\n",
 722                            irq);
 723                 goto err_unregister;
 724         }
 725
 726         /*
 727          * Vmbus interrupts can be handled concurrently on
 728          * different CPUs. Establish an appropriate interrupt flow
 729          * handler that can support this model.
 730          */
 731         irq_set_handler(irq, vmbus_flow_handler);
 732
 733         /*
 734          * Register our interrupt handler.
 735          */
 736         hv_register_vmbus_handler(irq, vmbus_isr);
 737
 738         ret = hv_synic_alloc();
 739         if (ret)
 740                 goto err_alloc;
 741         /*
 742          * Initialize the per-cpu interrupt state and
 743          * connect to the host.
 744          */
 745         on_each_cpu(hv_synic_init, NULL, 1);
 746         ret = vmbus_connect();
 747         if (ret)
 748                 goto err_alloc;
 749
 750         vmbus_request_offers();
 751
 752         return 0;
 753
 754 err_alloc:
 755         hv_synic_free();
 756         free_irq(irq, hv_acpi_dev);
 757
 758 err_unregister:
 759         bus_unregister(&hv_bus);
 760
 761 err_cleanup:
 762         hv_cleanup();
 763
 764         return ret;
 765 }
 766
 767 /**
 768  * __vmbus_child_driver_register - Register a vmbus's driver
 769  * @drv: Pointer to driver structure you want to register
 770  * @owner: owner module of the drv
 771  * @mod_name: module name string
 772  *
 773  * Registers the given driver with Linux through the 'driver_register()' call
 774  * and sets up the hyper-v vmbus handling for this driver.
 775  * It will return the state of the 'driver_register()' call.
 776  *
 777  */
 778 int __vmbus_driver_register(struct hv_driver *hv_driver, struct module *owner, const char *mod_name)
 779 {
 780         int ret;
 781
 782         pr_info("registering driver %s\n", hv_driver->name);
 783
 784         ret = vmbus_exists();
 785         if (ret < 0)
 786                 return ret;
 787
 788         hv_driver->driver.name = hv_driver->name;
 789         hv_driver->driver.owner = owner;
 790         hv_driver->driver.mod_name = mod_name;
 791         hv_driver->driver.bus = &hv_bus;
 792
 793         ret = driver_register(&hv_driver->driver);
 794
 795         return ret;
 796 }
 797 EXPORT_SYMBOL_GPL(__vmbus_driver_register);
 798
 799 /**
 800  * vmbus_driver_unregister() - Unregister a vmbus's driver
 801  * @drv: Pointer to driver structure you want to un-register
 802  *
 803  * Un-register the given driver that was previous registered with a call to
 804  * vmbus_driver_register()
 805  */
 806 void vmbus_driver_unregister(struct hv_driver *hv_driver)
 807 {
 808         pr_info("unregistering driver %s\n", hv_driver->name);
 809
 810         if (!vmbus_exists())
 811                 driver_unregister(&hv_driver->driver);
 812 }
 813 EXPORT_SYMBOL_GPL(vmbus_driver_unregister);
 814
 815 /*
 816  * vmbus_device_create - Creates and registers a new child device
 817  * on the vmbus.
 818  */
 819 struct hv_device *vmbus_device_create(uuid_le *type,
 820                                             uuid_le *instance,
 821                                             struct vmbus_channel *channel)
 822 {
 823         struct hv_device *child_device_obj;
 824
 825         child_device_obj = kzalloc(sizeof(struct hv_device), GFP_KERNEL);
 826         if (!child_device_obj) {
 827                 pr_err("Unable to allocate device object for child device\n");
 828                 return NULL;
 829         }
 830
 831         child_device_obj->channel = channel;
 832         memcpy(&child_device_obj->dev_type, type, sizeof(uuid_le));
 833         memcpy(&child_device_obj->dev_instance, instance,
 834                sizeof(uuid_le));
 835
 836
 837         return child_device_obj;
 838 }
 839
 840 /*
 841  * vmbus_device_register - Register the child device
 842  */
 843 int vmbus_device_register(struct hv_device *child_device_obj)
 844 {
 845         int ret = 0;
 846
 847         static atomic_t device_num = ATOMIC_INIT(0);
 848
 849         dev_set_name(&child_device_obj->device, "vmbus_0_%d",
 850                      atomic_inc_return(&device_num));
 851
 852         child_device_obj->device.bus = &hv_bus;
 853         child_device_obj->device.parent = &hv_acpi_dev->dev;
 854         child_device_obj->device.release = vmbus_device_release;
 855
 856         /*
 857          * Register with the LDM. This will kick off the driver/device
 858          * binding...which will eventually call vmbus_match() and vmbus_probe()
 859          */
 860         ret = device_register(&child_device_obj->device);
 861
 862         if (ret)
 863                 pr_err("Unable to register child device\n");
 864         else
 865                 pr_debug("child device %s registered\n",
 866                         dev_name(&child_device_obj->device));
 867
 868         return ret;
 869 }
 870
 871 /*
 872  * vmbus_device_unregister - Remove the specified child device
 873  * from the vmbus.
 874  */
 875 void vmbus_device_unregister(struct hv_device *device_obj)
 876 {
 877         pr_debug("child device %s unregistered\n",
 878                 dev_name(&device_obj->device));
 879
 880         /*
 881          * Kick off the process of unregistering the device.
 882          * This will call vmbus_remove() and eventually vmbus_device_release()
 883          */
 884         device_unregister(&device_obj->device);
 885 }
 886
 887
 888 /*
 889  * VMBUS is an acpi enumerated device. Get the the IRQ information
 890  * from DSDT.
 891  */
 892
 893 static acpi_status vmbus_walk_resources(struct acpi_resource *res, void *irq)
 894 {
 895
 896         if (res->type == ACPI_RESOURCE_TYPE_IRQ) {
 897                 struct acpi_resource_irq *irqp;
 898                 irqp = &res->data.irq;
 899
 900                 *((unsigned int *)irq) = irqp->interrupts[0];
 901         }
 902
 903         return AE_OK;
 904 }
 905
 906 static int vmbus_acpi_add(struct acpi_device *device)
 907 {
 908         acpi_status result;
 909
 910         hv_acpi_dev = device;
 911
 912         result = acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 913                                         vmbus_walk_resources, &irq);
 914
 915         if (ACPI_FAILURE(result)) {
 916                 complete(&probe_event);
 917                 return -ENODEV;
 918         }
 919         complete(&probe_event);
 920         return 0;
 921 }
 922
 923 static const struct acpi_device_id vmbus_acpi_device_ids[] = {
 924         {"VMBUS", 0},
 925         {"VMBus", 0},
 926         {"", 0},
 927 };
 928 MODULE_DEVICE_TABLE(acpi, vmbus_acpi_device_ids);
 929
 930 static struct acpi_driver vmbus_acpi_driver = {
 931         .name = "vmbus",
 932         .ids = vmbus_acpi_device_ids,
 933         .ops = {
 934                 .add = vmbus_acpi_add,
 935         },
 936 };
 937
 938 static int __init hv_acpi_init(void)
 939 {
 940         int ret, t;
 941
 942         if (x86_hyper != &x86_hyper_ms_hyperv)
 943                 return -ENODEV;
 944
 945         init_completion(&probe_event);
 946
 947         /*
 948          * Get irq resources first.
 949          */
 950
 951         ret = acpi_bus_register_driver(&vmbus_acpi_driver);
 952
 953         if (ret)
 954                 return ret;
 955
 956         t = wait_for_completion_timeout(&probe_event, 5*HZ);
 957         if (t == 0) {
 958                 ret = -ETIMEDOUT;
 959                 goto cleanup;
 960         }
 961
 962         if (irq <= 0) {
 963                 ret = -ENODEV;
 964                 goto cleanup;
 965         }
 966
 967         ret = vmbus_bus_init(irq);
 968         if (ret)
 969                 goto cleanup;
 970
 971         return 0;
 972
 973 cleanup:
 974         acpi_bus_unregister_driver(&vmbus_acpi_driver);
 975         hv_acpi_dev = NULL;
 976         return ret;
 977 }
 978
 979 static void __exit vmbus_exit(void)
 980 {
 981
 982         free_irq(irq, hv_acpi_dev);
 983         vmbus_free_channels();
 984         bus_unregister(&hv_bus);
 985         hv_cleanup();
 986         acpi_bus_unregister_driver(&vmbus_acpi_driver);
 987 }
 988
 989
 990 MODULE_LICENSE("GPL");
 991
 992 subsys_initcall(hv_acpi_init);
 993 module_exit(vmbus_exit);