drivers/hv/channel.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  */
  21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  22
  23 #include <linux/kernel.h>
  24 #include <linux/sched.h>
  25 #include <linux/wait.h>
  26 #include <linux/mm.h>
  27 #include <linux/slab.h>
  28 #include <linux/module.h>
  29 #include <linux/hyperv.h>
  30 #include <linux/uio.h>
  31 #include <linux/interrupt.h>
  32
  33 #include "hyperv_vmbus.h"
  34
  35 #define NUM_PAGES_SPANNED(addr, len) \
  36 ((PAGE_ALIGN(addr + len) >> PAGE_SHIFT) - (addr >> PAGE_SHIFT))
  37
  38 /*
  39  * vmbus_setevent- Trigger an event notification on the specified
  40  * channel.
  41  */
  42 void vmbus_setevent(struct vmbus_channel *channel)
  43 {
  44         struct hv_monitor_page *monitorpage;
  45
  46         /*
  47          * For channels marked as in "low latency" mode
  48          * bypass the monitor page mechanism.
  49          */
  50         if (channel->offermsg.monitor_allocated && !channel->low_latency) {
  51                 vmbus_send_interrupt(channel->offermsg.child_relid);
  52
  53                 /* Get the child to parent monitor page */
  54                 monitorpage = vmbus_connection.monitor_pages[1];
  55
  56                 sync_set_bit(channel->monitor_bit,
  57                         (unsigned long *)&monitorpage->trigger_group
  58                                         [channel->monitor_grp].pending);
  59
  60         } else {
  61                 vmbus_set_event(channel);
  62         }
  63 }
  64 EXPORT_SYMBOL_GPL(vmbus_setevent);
  65
  66 /*
  67  * vmbus_open - Open the specified channel.
  68  */
  69 int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
  70                      u32 recv_ringbuffer_size, void *userdata, u32 userdatalen,
  71                      void (*onchannelcallback)(void *context), void *context)
  72 {
  73         struct vmbus_channel_open_channel *open_msg;
  74         struct vmbus_channel_msginfo *open_info = NULL;
  75         unsigned long flags;
  76         int ret, err = 0;
  77         struct page *page;
  78
  79         if (send_ringbuffer_size % PAGE_SIZE ||
  80             recv_ringbuffer_size % PAGE_SIZE)
  81                 return -EINVAL;
  82
  83         spin_lock_irqsave(&newchannel->lock, flags);
  84         if (newchannel->state == CHANNEL_OPEN_STATE) {
  85                 newchannel->state = CHANNEL_OPENING_STATE;
  86         } else {
  87                 spin_unlock_irqrestore(&newchannel->lock, flags);
  88                 return -EINVAL;
  89         }
  90         spin_unlock_irqrestore(&newchannel->lock, flags);
  91
  92         newchannel->onchannel_callback = onchannelcallback;
  93         newchannel->channel_callback_context = context;
  94
  95         /* Allocate the ring buffer */
  96         page = alloc_pages_node(cpu_to_node(newchannel->target_cpu),
  97                                 GFP_KERNEL|__GFP_ZERO,
  98                                 get_order(send_ringbuffer_size +
  99                                 recv_ringbuffer_size));
 100
 101         if (!page)
 102                 page = alloc_pages(GFP_KERNEL|__GFP_ZERO,
 103                                    get_order(send_ringbuffer_size +
 104                                              recv_ringbuffer_size));
 105
 106         if (!page) {
 107                 err = -ENOMEM;
 108                 goto error_set_chnstate;
 109         }
 110
 111         newchannel->ringbuffer_pages = page_address(page);
 112         newchannel->ringbuffer_pagecount = (send_ringbuffer_size +
 113                                            recv_ringbuffer_size) >> PAGE_SHIFT;
 114
 115         ret = hv_ringbuffer_init(&newchannel->outbound, page,
 116                                  send_ringbuffer_size >> PAGE_SHIFT);
 117
 118         if (ret != 0) {
 119                 err = ret;
 120                 goto error_free_pages;
 121         }
 122
 123         ret = hv_ringbuffer_init(&newchannel->inbound,
 124                                  &page[send_ringbuffer_size >> PAGE_SHIFT],
 125                                  recv_ringbuffer_size >> PAGE_SHIFT);
 126         if (ret != 0) {
 127                 err = ret;
 128                 goto error_free_pages;
 129         }
 130
 131
 132         /* Establish the gpadl for the ring buffer */
 133         newchannel->ringbuffer_gpadlhandle = 0;
 134
 135         ret = vmbus_establish_gpadl(newchannel,
 136                                     page_address(page),
 137                                     send_ringbuffer_size +
 138                                     recv_ringbuffer_size,
 139                                     &newchannel->ringbuffer_gpadlhandle);
 140
 141         if (ret != 0) {
 142                 err = ret;
 143                 goto error_free_pages;
 144         }
 145
 146         /* Create and init the channel open message */
 147         open_info = kmalloc(sizeof(*open_info) +
 148                            sizeof(struct vmbus_channel_open_channel),
 149                            GFP_KERNEL);
 150         if (!open_info) {
 151                 err = -ENOMEM;
 152                 goto error_free_gpadl;
 153         }
 154
 155         init_completion(&open_info->waitevent);
 156         open_info->waiting_channel = newchannel;
 157
 158         open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
 159         open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
 160         open_msg->openid = newchannel->offermsg.child_relid;
 161         open_msg->child_relid = newchannel->offermsg.child_relid;
 162         open_msg->ringbuffer_gpadlhandle = newchannel->ringbuffer_gpadlhandle;
 163         open_msg->downstream_ringbuffer_pageoffset = send_ringbuffer_size >>
 164                                                   PAGE_SHIFT;
 165         open_msg->target_vp = newchannel->target_vp;
 166
 167         if (userdatalen > MAX_USER_DEFINED_BYTES) {
 168                 err = -EINVAL;
 169                 goto error_free_gpadl;
 170         }
 171
 172         if (userdatalen)
 173                 memcpy(open_msg->userdata, userdata, userdatalen);
 174
 175         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 176         list_add_tail(&open_info->msglistentry,
 177                       &vmbus_connection.chn_msg_list);
 178         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 179
 180         if (newchannel->rescind) {
 181                 err = -ENODEV;
 182                 goto error_free_gpadl;
 183         }
 184
 185         ret = vmbus_post_msg(open_msg,
 186                              sizeof(struct vmbus_channel_open_channel), true);
 187
 188         if (ret != 0) {
 189                 err = ret;
 190                 goto error_clean_msglist;
 191         }
 192
 193         wait_for_completion(&open_info->waitevent);
 194
 195         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 196         list_del(&open_info->msglistentry);
 197         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 198
 199         if (newchannel->rescind) {
 200                 err = -ENODEV;
 201                 goto error_free_gpadl;
 202         }
 203
 204         if (open_info->response.open_result.status) {
 205                 err = -EAGAIN;
 206                 goto error_free_gpadl;
 207         }
 208
 209         newchannel->state = CHANNEL_OPENED_STATE;
 210         kfree(open_info);
 211         return 0;
 212
 213 error_clean_msglist:
 214         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 215         list_del(&open_info->msglistentry);
 216         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 217
 218 error_free_gpadl:
 219         vmbus_teardown_gpadl(newchannel, newchannel->ringbuffer_gpadlhandle);
 220         kfree(open_info);
 221 error_free_pages:
 222         hv_ringbuffer_cleanup(&newchannel->outbound);
 223         hv_ringbuffer_cleanup(&newchannel->inbound);
 224         __free_pages(page,
 225                      get_order(send_ringbuffer_size + recv_ringbuffer_size));
 226 error_set_chnstate:
 227         newchannel->state = CHANNEL_OPEN_STATE;
 228         return err;
 229 }
 230 EXPORT_SYMBOL_GPL(vmbus_open);
 231
 232 /* Used for Hyper-V Socket: a guest client's connect() to the host */
 233 int vmbus_send_tl_connect_request(const uuid_le *shv_guest_servie_id,
 234                                   const uuid_le *shv_host_servie_id)
 235 {
 236         struct vmbus_channel_tl_connect_request conn_msg;
 237
 238         memset(&conn_msg, 0, sizeof(conn_msg));
 239         conn_msg.header.msgtype = CHANNELMSG_TL_CONNECT_REQUEST;
 240         conn_msg.guest_endpoint_id = *shv_guest_servie_id;
 241         conn_msg.host_service_id = *shv_host_servie_id;
 242
 243         return vmbus_post_msg(&conn_msg, sizeof(conn_msg), true);
 244 }
 245 EXPORT_SYMBOL_GPL(vmbus_send_tl_connect_request);
 246
 247 /*
 248  * create_gpadl_header - Creates a gpadl for the specified buffer
 249  */
 250 static int create_gpadl_header(void *kbuffer, u32 size,
 251                                struct vmbus_channel_msginfo **msginfo)
 252 {
 253         int i;
 254         int pagecount;
 255         struct vmbus_channel_gpadl_header *gpadl_header;
 256         struct vmbus_channel_gpadl_body *gpadl_body;
 257         struct vmbus_channel_msginfo *msgheader;
 258         struct vmbus_channel_msginfo *msgbody = NULL;
 259         u32 msgsize;
 260
 261         int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
 262
 263         pagecount = size >> PAGE_SHIFT;
 264
 265         /* do we need a gpadl body msg */
 266         pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 267                   sizeof(struct vmbus_channel_gpadl_header) -
 268                   sizeof(struct gpa_range);
 269         pfncount = pfnsize / sizeof(u64);
 270
 271         if (pagecount > pfncount) {
 272                 /* we need a gpadl body */
 273                 /* fill in the header */
 274                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 275                           sizeof(struct vmbus_channel_gpadl_header) +
 276                           sizeof(struct gpa_range) + pfncount * sizeof(u64);
 277                 msgheader =  kzalloc(msgsize, GFP_KERNEL);
 278                 if (!msgheader)
 279                         goto nomem;
 280
 281                 INIT_LIST_HEAD(&msgheader->submsglist);
 282                 msgheader->msgsize = msgsize;
 283
 284                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 285                         msgheader->msg;
 286                 gpadl_header->rangecount = 1;
 287                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 288                                          pagecount * sizeof(u64);
 289                 gpadl_header->range[0].byte_offset = 0;
 290                 gpadl_header->range[0].byte_count = size;
 291                 for (i = 0; i < pfncount; i++)
 292                         gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
 293                                 kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 294                 *msginfo = msgheader;
 295
 296                 pfnsum = pfncount;
 297                 pfnleft = pagecount - pfncount;
 298
 299                 /* how many pfns can we fit */
 300                 pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 301                           sizeof(struct vmbus_channel_gpadl_body);
 302                 pfncount = pfnsize / sizeof(u64);
 303
 304                 /* fill in the body */
 305                 while (pfnleft) {
 306                         if (pfnleft > pfncount)
 307                                 pfncurr = pfncount;
 308                         else
 309                                 pfncurr = pfnleft;
 310
 311                         msgsize = sizeof(struct vmbus_channel_msginfo) +
 312                                   sizeof(struct vmbus_channel_gpadl_body) +
 313                                   pfncurr * sizeof(u64);
 314                         msgbody = kzalloc(msgsize, GFP_KERNEL);
 315
 316                         if (!msgbody) {
 317                                 struct vmbus_channel_msginfo *pos = NULL;
 318                                 struct vmbus_channel_msginfo *tmp = NULL;
 319                                 /*
 320                                  * Free up all the allocated messages.
 321                                  */
 322                                 list_for_each_entry_safe(pos, tmp,
 323                                         &msgheader->submsglist,
 324                                         msglistentry) {
 325
 326                                         list_del(&pos->msglistentry);
 327                                         kfree(pos);
 328                                 }
 329
 330                                 goto nomem;
 331                         }
 332
 333                         msgbody->msgsize = msgsize;
 334                         gpadl_body =
 335                                 (struct vmbus_channel_gpadl_body *)msgbody->msg;
 336
 337                         /*
 338                          * Gpadl is u32 and we are using a pointer which could
 339                          * be 64-bit
 340                          * This is governed by the guest/host protocol and
 341                          * so the hypervisor guarantees that this is ok.
 342                          */
 343                         for (i = 0; i < pfncurr; i++)
 344                                 gpadl_body->pfn[i] = slow_virt_to_phys(
 345                                         kbuffer + PAGE_SIZE * (pfnsum + i)) >>
 346                                         PAGE_SHIFT;
 347
 348                         /* add to msg header */
 349                         list_add_tail(&msgbody->msglistentry,
 350                                       &msgheader->submsglist);
 351                         pfnsum += pfncurr;
 352                         pfnleft -= pfncurr;
 353                 }
 354         } else {
 355                 /* everything fits in a header */
 356                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 357                           sizeof(struct vmbus_channel_gpadl_header) +
 358                           sizeof(struct gpa_range) + pagecount * sizeof(u64);
 359                 msgheader = kzalloc(msgsize, GFP_KERNEL);
 360                 if (msgheader == NULL)
 361                         goto nomem;
 362
 363                 INIT_LIST_HEAD(&msgheader->submsglist);
 364                 msgheader->msgsize = msgsize;
 365
 366                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 367                         msgheader->msg;
 368                 gpadl_header->rangecount = 1;
 369                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 370                                          pagecount * sizeof(u64);
 371                 gpadl_header->range[0].byte_offset = 0;
 372                 gpadl_header->range[0].byte_count = size;
 373                 for (i = 0; i < pagecount; i++)
 374                         gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
 375                                 kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 376
 377                 *msginfo = msgheader;
 378         }
 379
 380         return 0;
 381 nomem:
 382         kfree(msgheader);
 383         kfree(msgbody);
 384         return -ENOMEM;
 385 }
 386
 387 /*
 388  * vmbus_establish_gpadl - Establish a GPADL for the specified buffer
 389  *
 390  * @channel: a channel
 391  * @kbuffer: from kmalloc or vmalloc
 392  * @size: page-size multiple
 393  * @gpadl_handle: some funky thing
 394  */
 395 int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
 396                                u32 size, u32 *gpadl_handle)
 397 {
 398         struct vmbus_channel_gpadl_header *gpadlmsg;
 399         struct vmbus_channel_gpadl_body *gpadl_body;
 400         struct vmbus_channel_msginfo *msginfo = NULL;
 401         struct vmbus_channel_msginfo *submsginfo, *tmp;
 402         struct list_head *curr;
 403         u32 next_gpadl_handle;
 404         unsigned long flags;
 405         int ret = 0;
 406
 407         next_gpadl_handle =
 408                 (atomic_inc_return(&vmbus_connection.next_gpadl_handle) - 1);
 409
 410         ret = create_gpadl_header(kbuffer, size, &msginfo);
 411         if (ret)
 412                 return ret;
 413
 414         init_completion(&msginfo->waitevent);
 415         msginfo->waiting_channel = channel;
 416
 417         gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
 418         gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
 419         gpadlmsg->child_relid = channel->offermsg.child_relid;
 420         gpadlmsg->gpadl = next_gpadl_handle;
 421
 422
 423         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 424         list_add_tail(&msginfo->msglistentry,
 425                       &vmbus_connection.chn_msg_list);
 426
 427         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 428
 429         if (channel->rescind) {
 430                 ret = -ENODEV;
 431                 goto cleanup;
 432         }
 433
 434         ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize -
 435                              sizeof(*msginfo), true);
 436         if (ret != 0)
 437                 goto cleanup;
 438
 439         list_for_each(curr, &msginfo->submsglist) {
 440                 submsginfo = (struct vmbus_channel_msginfo *)curr;
 441                 gpadl_body =
 442                         (struct vmbus_channel_gpadl_body *)submsginfo->msg;
 443
 444                 gpadl_body->header.msgtype =
 445                         CHANNELMSG_GPADL_BODY;
 446                 gpadl_body->gpadl = next_gpadl_handle;
 447
 448                 ret = vmbus_post_msg(gpadl_body,
 449                                      submsginfo->msgsize - sizeof(*submsginfo),
 450                                      true);
 451                 if (ret != 0)
 452                         goto cleanup;
 453
 454         }
 455         wait_for_completion(&msginfo->waitevent);
 456
 457         if (msginfo->response.gpadl_created.creation_status != 0) {
 458                 pr_err("Failed to establish GPADL: err = 0x%x\n",
 459                        msginfo->response.gpadl_created.creation_status);
 460
 461                 ret = -EDQUOT;
 462                 goto cleanup;
 463         }
 464
 465         if (channel->rescind) {
 466                 ret = -ENODEV;
 467                 goto cleanup;
 468         }
 469
 470         /* At this point, we received the gpadl created msg */
 471         *gpadl_handle = gpadlmsg->gpadl;
 472
 473 cleanup:
 474         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 475         list_del(&msginfo->msglistentry);
 476         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 477         list_for_each_entry_safe(submsginfo, tmp, &msginfo->submsglist,
 478                                  msglistentry) {
 479                 kfree(submsginfo);
 480         }
 481
 482         kfree(msginfo);
 483         return ret;
 484 }
 485 EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
 486
 487 /*
 488  * vmbus_teardown_gpadl -Teardown the specified GPADL handle
 489  */
 490 int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
 491 {
 492         struct vmbus_channel_gpadl_teardown *msg;
 493         struct vmbus_channel_msginfo *info;
 494         unsigned long flags;
 495         int ret;
 496
 497         info = kmalloc(sizeof(*info) +
 498                        sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
 499         if (!info)
 500                 return -ENOMEM;
 501
 502         init_completion(&info->waitevent);
 503         info->waiting_channel = channel;
 504
 505         msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
 506
 507         msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
 508         msg->child_relid = channel->offermsg.child_relid;
 509         msg->gpadl = gpadl_handle;
 510
 511         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 512         list_add_tail(&info->msglistentry,
 513                       &vmbus_connection.chn_msg_list);
 514         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 515
 516         if (channel->rescind)
 517                 goto post_msg_err;
 518
 519         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_gpadl_teardown),
 520                              true);
 521
 522         if (ret)
 523                 goto post_msg_err;
 524
 525         wait_for_completion(&info->waitevent);
 526
 527 post_msg_err:
 528         /*
 529          * If the channel has been rescinded;
 530          * we will be awakened by the rescind
 531          * handler; set the error code to zero so we don't leak memory.
 532          */
 533         if (channel->rescind)
 534                 ret = 0;
 535
 536         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 537         list_del(&info->msglistentry);
 538         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 539
 540         kfree(info);
 541         return ret;
 542 }
 543 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
 544
 545 static void reset_channel_cb(void *arg)
 546 {
 547         struct vmbus_channel *channel = arg;
 548
 549         channel->onchannel_callback = NULL;
 550 }
 551
 552 void vmbus_reset_channel_cb(struct vmbus_channel *channel)
 553 {
 554         /*
 555          * vmbus_on_event(), running in the per-channel tasklet, can race
 556          * with vmbus_close_internal() in the case of SMP guest, e.g., when
 557          * the former is accessing channel->inbound.ring_buffer, the latter
 558          * could be freeing the ring_buffer pages, so here we must stop it
 559          * first.
 560          */
 561         tasklet_disable(&channel->callback_event);
 562
 563         channel->sc_creation_callback = NULL;
 564
 565         /* Stop the callback asap */
 566         if (channel->target_cpu != get_cpu()) {
 567                 put_cpu();
 568                 smp_call_function_single(channel->target_cpu, reset_channel_cb,
 569                                          channel, true);
 570         } else {
 571                 reset_channel_cb(channel);
 572                 put_cpu();
 573         }
 574
 575         /* Re-enable tasklet for use on re-open */
 576         tasklet_enable(&channel->callback_event);
 577 }
 578
 579 static int vmbus_close_internal(struct vmbus_channel *channel)
 580 {
 581         struct vmbus_channel_close_channel *msg;
 582         int ret;
 583
 584         vmbus_reset_channel_cb(channel);
 585
 586         /*
 587          * In case a device driver's probe() fails (e.g.,
 588          * util_probe() -> vmbus_open() returns -ENOMEM) and the device is
 589          * rescinded later (e.g., we dynamically disable an Integrated Service
 590          * in Hyper-V Manager), the driver's remove() invokes vmbus_close():
 591          * here we should skip most of the below cleanup work.
 592          */
 593         if (channel->state != CHANNEL_OPENED_STATE) {
 594                 ret = -EINVAL;
 595                 goto out;
 596         }
 597
 598         channel->state = CHANNEL_OPEN_STATE;
 599
 600         /* Send a closing message */
 601
 602         msg = &channel->close_msg.msg;
 603
 604         msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
 605         msg->child_relid = channel->offermsg.child_relid;
 606
 607         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel),
 608                              true);
 609
 610         if (ret) {
 611                 pr_err("Close failed: close post msg return is %d\n", ret);
 612                 /*
 613                  * If we failed to post the close msg,
 614                  * it is perhaps better to leak memory.
 615                  */
 616                 goto out;
 617         }
 618
 619         /* Tear down the gpadl for the channel's ring buffer */
 620         if (channel->ringbuffer_gpadlhandle) {
 621                 ret = vmbus_teardown_gpadl(channel,
 622                                            channel->ringbuffer_gpadlhandle);
 623                 if (ret) {
 624                         pr_err("Close failed: teardown gpadl return %d\n", ret);
 625                         /*
 626                          * If we failed to teardown gpadl,
 627                          * it is perhaps better to leak memory.
 628                          */
 629                         goto out;
 630                 }
 631         }
 632
 633         /* Cleanup the ring buffers for this channel */
 634         hv_ringbuffer_cleanup(&channel->outbound);
 635         hv_ringbuffer_cleanup(&channel->inbound);
 636
 637         free_pages((unsigned long)channel->ringbuffer_pages,
 638                 get_order(channel->ringbuffer_pagecount * PAGE_SIZE));
 639
 640 out:
 641         return ret;
 642 }
 643
 644 /*
 645  * vmbus_close - Close the specified channel
 646  */
 647 void vmbus_close(struct vmbus_channel *channel)
 648 {
 649         struct list_head *cur, *tmp;
 650         struct vmbus_channel *cur_channel;
 651
 652         if (channel->primary_channel != NULL) {
 653                 /*
 654                  * We will only close sub-channels when
 655                  * the primary is closed.
 656                  */
 657                 return;
 658         }
 659         /*
 660          * Close all the sub-channels first and then close the
 661          * primary channel.
 662          */
 663         list_for_each_safe(cur, tmp, &channel->sc_list) {
 664                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 665                 if (cur_channel->rescind) {
 666                         wait_for_completion(&cur_channel->rescind_event);
 667                         mutex_lock(&vmbus_connection.channel_mutex);
 668                         vmbus_close_internal(cur_channel);
 669                         hv_process_channel_removal(
 670                                            cur_channel->offermsg.child_relid);
 671                 } else {
 672                         mutex_lock(&vmbus_connection.channel_mutex);
 673                         vmbus_close_internal(cur_channel);
 674                 }
 675                 mutex_unlock(&vmbus_connection.channel_mutex);
 676         }
 677         /*
 678          * Now close the primary.
 679          */
 680         mutex_lock(&vmbus_connection.channel_mutex);
 681         vmbus_close_internal(channel);
 682         mutex_unlock(&vmbus_connection.channel_mutex);
 683 }
 684 EXPORT_SYMBOL_GPL(vmbus_close);
 685
 686 /**
 687  * vmbus_sendpacket() - Send the specified buffer on the given channel
 688  * @channel: Pointer to vmbus_channel structure.
 689  * @buffer: Pointer to the buffer you want to receive the data into.
 690  * @bufferlen: Maximum size of what the the buffer will hold
 691  * @requestid: Identifier of the request
 692  * @type: Type of packet that is being send e.g. negotiate, time
 693  * packet etc.
 694  *
 695  * Sends data in @buffer directly to hyper-v via the vmbus
 696  * This will send the data unparsed to hyper-v.
 697  *
 698  * Mainly used by Hyper-V drivers.
 699  */
 700 int vmbus_sendpacket(struct vmbus_channel *channel, void *buffer,
 701                            u32 bufferlen, u64 requestid,
 702                            enum vmbus_packet_type type, u32 flags)
 703 {
 704         struct vmpacket_descriptor desc;
 705         u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
 706         u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 707         struct kvec bufferlist[3];
 708         u64 aligned_data = 0;
 709         int num_vecs = ((bufferlen != 0) ? 3 : 1);
 710
 711
 712         /* Setup the descriptor */
 713         desc.type = type; /* VmbusPacketTypeDataInBand; */
 714         desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
 715         /* in 8-bytes granularity */
 716         desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3;
 717         desc.len8 = (u16)(packetlen_aligned >> 3);
 718         desc.trans_id = requestid;
 719
 720         bufferlist[0].iov_base = &desc;
 721         bufferlist[0].iov_len = sizeof(struct vmpacket_descriptor);
 722         bufferlist[1].iov_base = buffer;
 723         bufferlist[1].iov_len = bufferlen;
 724         bufferlist[2].iov_base = &aligned_data;
 725         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 726
 727         return hv_ringbuffer_write(channel, bufferlist, num_vecs);
 728 }
 729 EXPORT_SYMBOL(vmbus_sendpacket);
 730
 731 /*
 732  * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
 733  * packets using a GPADL Direct packet type. This interface allows you
 734  * to control notifying the host. This will be useful for sending
 735  * batched data. Also the sender can control the send flags
 736  * explicitly.
 737  */
 738 int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
 739                                 struct hv_page_buffer pagebuffers[],
 740                                 u32 pagecount, void *buffer, u32 bufferlen,
 741                                 u64 requestid)
 742 {
 743         int i;
 744         struct vmbus_channel_packet_page_buffer desc;
 745         u32 descsize;
 746         u32 packetlen;
 747         u32 packetlen_aligned;
 748         struct kvec bufferlist[3];
 749         u64 aligned_data = 0;
 750
 751         if (pagecount > MAX_PAGE_BUFFER_COUNT)
 752                 return -EINVAL;
 753
 754         /*
 755          * Adjust the size down since vmbus_channel_packet_page_buffer is the
 756          * largest size we support
 757          */
 758         descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
 759                           ((MAX_PAGE_BUFFER_COUNT - pagecount) *
 760                           sizeof(struct hv_page_buffer));
 761         packetlen = descsize + bufferlen;
 762         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 763
 764         /* Setup the descriptor */
 765         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
 766         desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 767         desc.dataoffset8 = descsize >> 3; /* in 8-bytes granularity */
 768         desc.length8 = (u16)(packetlen_aligned >> 3);
 769         desc.transactionid = requestid;
 770         desc.rangecount = pagecount;
 771
 772         for (i = 0; i < pagecount; i++) {
 773                 desc.range[i].len = pagebuffers[i].len;
 774                 desc.range[i].offset = pagebuffers[i].offset;
 775                 desc.range[i].pfn        = pagebuffers[i].pfn;
 776         }
 777
 778         bufferlist[0].iov_base = &desc;
 779         bufferlist[0].iov_len = descsize;
 780         bufferlist[1].iov_base = buffer;
 781         bufferlist[1].iov_len = bufferlen;
 782         bufferlist[2].iov_base = &aligned_data;
 783         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 784
 785         return hv_ringbuffer_write(channel, bufferlist, 3);
 786 }
 787 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
 788
 789 /*
 790  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
 791  * using a GPADL Direct packet type.
 792  * The buffer includes the vmbus descriptor.
 793  */
 794 int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
 795                               struct vmbus_packet_mpb_array *desc,
 796                               u32 desc_size,
 797                               void *buffer, u32 bufferlen, u64 requestid)
 798 {
 799         u32 packetlen;
 800         u32 packetlen_aligned;
 801         struct kvec bufferlist[3];
 802         u64 aligned_data = 0;
 803
 804         packetlen = desc_size + bufferlen;
 805         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 806
 807         /* Setup the descriptor */
 808         desc->type = VM_PKT_DATA_USING_GPA_DIRECT;
 809         desc->flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 810         desc->dataoffset8 = desc_size >> 3; /* in 8-bytes granularity */
 811         desc->length8 = (u16)(packetlen_aligned >> 3);
 812         desc->transactionid = requestid;
 813         desc->rangecount = 1;
 814
 815         bufferlist[0].iov_base = desc;
 816         bufferlist[0].iov_len = desc_size;
 817         bufferlist[1].iov_base = buffer;
 818         bufferlist[1].iov_len = bufferlen;
 819         bufferlist[2].iov_base = &aligned_data;
 820         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 821
 822         return hv_ringbuffer_write(channel, bufferlist, 3);
 823 }
 824 EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc);
 825
 826 /**
 827  * vmbus_recvpacket() - Retrieve the user packet on the specified channel
 828  * @channel: Pointer to vmbus_channel structure.
 829  * @buffer: Pointer to the buffer you want to receive the data into.
 830  * @bufferlen: Maximum size of what the the buffer will hold
 831  * @buffer_actual_len: The actual size of the data after it was received
 832  * @requestid: Identifier of the request
 833  *
 834  * Receives directly from the hyper-v vmbus and puts the data it received
 835  * into Buffer. This will receive the data unparsed from hyper-v.
 836  *
 837  * Mainly used by Hyper-V drivers.
 838  */
 839 static inline int
 840 __vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
 841                    u32 bufferlen, u32 *buffer_actual_len, u64 *requestid,
 842                    bool raw)
 843 {
 844         return hv_ringbuffer_read(channel, buffer, bufferlen,
 845                                   buffer_actual_len, requestid, raw);
 846
 847 }
 848
 849 int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
 850                      u32 bufferlen, u32 *buffer_actual_len,
 851                      u64 *requestid)
 852 {
 853         return __vmbus_recvpacket(channel, buffer, bufferlen,
 854                                   buffer_actual_len, requestid, false);
 855 }
 856 EXPORT_SYMBOL(vmbus_recvpacket);
 857
 858 /*
 859  * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
 860  */
 861 int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
 862                               u32 bufferlen, u32 *buffer_actual_len,
 863                               u64 *requestid)
 864 {
 865         return __vmbus_recvpacket(channel, buffer, bufferlen,
 866                                   buffer_actual_len, requestid, true);
 867 }
 868 EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);