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 static 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) &&
  51             (!channel->low_latency)) {
  52                 /* Each u32 represents 32 channels */
  53                 sync_set_bit(channel->offermsg.child_relid & 31,
  54                         (unsigned long *) vmbus_connection.send_int_page +
  55                         (channel->offermsg.child_relid >> 5));
  56
  57                 /* Get the child to parent monitor page */
  58                 monitorpage = vmbus_connection.monitor_pages[1];
  59
  60                 sync_set_bit(channel->monitor_bit,
  61                         (unsigned long *)&monitorpage->trigger_group
  62                                         [channel->monitor_grp].pending);
  63
  64         } else {
  65                 vmbus_set_event(channel);
  66         }
  67 }
  68
  69 /*
  70  * vmbus_open - Open the specified channel.
  71  */
  72 int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
  73                      u32 recv_ringbuffer_size, void *userdata, u32 userdatalen,
  74                      void (*onchannelcallback)(void *context), void *context)
  75 {
  76         struct vmbus_channel_open_channel *open_msg;
  77         struct vmbus_channel_msginfo *open_info = NULL;
  78         unsigned long flags;
  79         int ret, err = 0;
  80         struct page *page;
  81
  82         if (send_ringbuffer_size % PAGE_SIZE ||
  83             recv_ringbuffer_size % PAGE_SIZE)
  84                 return -EINVAL;
  85
  86         spin_lock_irqsave(&newchannel->lock, flags);
  87         if (newchannel->state == CHANNEL_OPEN_STATE) {
  88                 newchannel->state = CHANNEL_OPENING_STATE;
  89         } else {
  90                 spin_unlock_irqrestore(&newchannel->lock, flags);
  91                 return -EINVAL;
  92         }
  93         spin_unlock_irqrestore(&newchannel->lock, flags);
  94
  95         newchannel->onchannel_callback = onchannelcallback;
  96         newchannel->channel_callback_context = context;
  97
  98         /* Allocate the ring buffer */
  99         page = alloc_pages_node(cpu_to_node(newchannel->target_cpu),
 100                                 GFP_KERNEL|__GFP_ZERO,
 101                                 get_order(send_ringbuffer_size +
 102                                 recv_ringbuffer_size));
 103
 104         if (!page)
 105                 page = alloc_pages(GFP_KERNEL|__GFP_ZERO,
 106                                    get_order(send_ringbuffer_size +
 107                                              recv_ringbuffer_size));
 108
 109         if (!page) {
 110                 err = -ENOMEM;
 111                 goto error_set_chnstate;
 112         }
 113
 114         newchannel->ringbuffer_pages = page_address(page);
 115         newchannel->ringbuffer_pagecount = (send_ringbuffer_size +
 116                                            recv_ringbuffer_size) >> PAGE_SHIFT;
 117
 118         ret = hv_ringbuffer_init(&newchannel->outbound, page,
 119                                  send_ringbuffer_size >> PAGE_SHIFT);
 120
 121         if (ret != 0) {
 122                 err = ret;
 123                 goto error_free_pages;
 124         }
 125
 126         ret = hv_ringbuffer_init(&newchannel->inbound,
 127                                  &page[send_ringbuffer_size >> PAGE_SHIFT],
 128                                  recv_ringbuffer_size >> PAGE_SHIFT);
 129         if (ret != 0) {
 130                 err = ret;
 131                 goto error_free_pages;
 132         }
 133
 134
 135         /* Establish the gpadl for the ring buffer */
 136         newchannel->ringbuffer_gpadlhandle = 0;
 137
 138         ret = vmbus_establish_gpadl(newchannel,
 139                                     page_address(page),
 140                                     send_ringbuffer_size +
 141                                     recv_ringbuffer_size,
 142                                     &newchannel->ringbuffer_gpadlhandle);
 143
 144         if (ret != 0) {
 145                 err = ret;
 146                 goto error_free_pages;
 147         }
 148
 149         /* Create and init the channel open message */
 150         open_info = kmalloc(sizeof(*open_info) +
 151                            sizeof(struct vmbus_channel_open_channel),
 152                            GFP_KERNEL);
 153         if (!open_info) {
 154                 err = -ENOMEM;
 155                 goto error_free_gpadl;
 156         }
 157
 158         init_completion(&open_info->waitevent);
 159
 160         open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
 161         open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
 162         open_msg->openid = newchannel->offermsg.child_relid;
 163         open_msg->child_relid = newchannel->offermsg.child_relid;
 164         open_msg->ringbuffer_gpadlhandle = newchannel->ringbuffer_gpadlhandle;
 165         open_msg->downstream_ringbuffer_pageoffset = send_ringbuffer_size >>
 166                                                   PAGE_SHIFT;
 167         open_msg->target_vp = newchannel->target_vp;
 168
 169         if (userdatalen > MAX_USER_DEFINED_BYTES) {
 170                 err = -EINVAL;
 171                 goto error_free_gpadl;
 172         }
 173
 174         if (userdatalen)
 175                 memcpy(open_msg->userdata, userdata, userdatalen);
 176
 177         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 178         list_add_tail(&open_info->msglistentry,
 179                       &vmbus_connection.chn_msg_list);
 180         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 181
 182         ret = vmbus_post_msg(open_msg,
 183                                sizeof(struct vmbus_channel_open_channel));
 184
 185         if (ret != 0) {
 186                 err = ret;
 187                 goto error_clean_msglist;
 188         }
 189
 190         wait_for_completion(&open_info->waitevent);
 191
 192         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 193         list_del(&open_info->msglistentry);
 194         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 195
 196         if (open_info->response.open_result.status) {
 197                 err = -EAGAIN;
 198                 goto error_free_gpadl;
 199         }
 200
 201         newchannel->state = CHANNEL_OPENED_STATE;
 202         kfree(open_info);
 203         return 0;
 204
 205 error_clean_msglist:
 206         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 207         list_del(&open_info->msglistentry);
 208         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 209
 210 error_free_gpadl:
 211         vmbus_teardown_gpadl(newchannel, newchannel->ringbuffer_gpadlhandle);
 212         kfree(open_info);
 213 error_free_pages:
 214         hv_ringbuffer_cleanup(&newchannel->outbound);
 215         hv_ringbuffer_cleanup(&newchannel->inbound);
 216         __free_pages(page,
 217                      get_order(send_ringbuffer_size + recv_ringbuffer_size));
 218 error_set_chnstate:
 219         newchannel->state = CHANNEL_OPEN_STATE;
 220         return err;
 221 }
 222 EXPORT_SYMBOL_GPL(vmbus_open);
 223
 224 /* Used for Hyper-V Socket: a guest client's connect() to the host */
 225 int vmbus_send_tl_connect_request(const uuid_le *shv_guest_servie_id,
 226                                   const uuid_le *shv_host_servie_id)
 227 {
 228         struct vmbus_channel_tl_connect_request conn_msg;
 229
 230         memset(&conn_msg, 0, sizeof(conn_msg));
 231         conn_msg.header.msgtype = CHANNELMSG_TL_CONNECT_REQUEST;
 232         conn_msg.guest_endpoint_id = *shv_guest_servie_id;
 233         conn_msg.host_service_id = *shv_host_servie_id;
 234
 235         return vmbus_post_msg(&conn_msg, sizeof(conn_msg));
 236 }
 237 EXPORT_SYMBOL_GPL(vmbus_send_tl_connect_request);
 238
 239 /*
 240  * create_gpadl_header - Creates a gpadl for the specified buffer
 241  */
 242 static int create_gpadl_header(void *kbuffer, u32 size,
 243                                struct vmbus_channel_msginfo **msginfo)
 244 {
 245         int i;
 246         int pagecount;
 247         struct vmbus_channel_gpadl_header *gpadl_header;
 248         struct vmbus_channel_gpadl_body *gpadl_body;
 249         struct vmbus_channel_msginfo *msgheader;
 250         struct vmbus_channel_msginfo *msgbody = NULL;
 251         u32 msgsize;
 252
 253         int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
 254
 255         pagecount = size >> PAGE_SHIFT;
 256
 257         /* do we need a gpadl body msg */
 258         pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 259                   sizeof(struct vmbus_channel_gpadl_header) -
 260                   sizeof(struct gpa_range);
 261         pfncount = pfnsize / sizeof(u64);
 262
 263         if (pagecount > pfncount) {
 264                 /* we need a gpadl body */
 265                 /* fill in the header */
 266                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 267                           sizeof(struct vmbus_channel_gpadl_header) +
 268                           sizeof(struct gpa_range) + pfncount * sizeof(u64);
 269                 msgheader =  kzalloc(msgsize, GFP_KERNEL);
 270                 if (!msgheader)
 271                         goto nomem;
 272
 273                 INIT_LIST_HEAD(&msgheader->submsglist);
 274                 msgheader->msgsize = msgsize;
 275
 276                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 277                         msgheader->msg;
 278                 gpadl_header->rangecount = 1;
 279                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 280                                          pagecount * sizeof(u64);
 281                 gpadl_header->range[0].byte_offset = 0;
 282                 gpadl_header->range[0].byte_count = size;
 283                 for (i = 0; i < pfncount; i++)
 284                         gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
 285                                 kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 286                 *msginfo = msgheader;
 287
 288                 pfnsum = pfncount;
 289                 pfnleft = pagecount - pfncount;
 290
 291                 /* how many pfns can we fit */
 292                 pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 293                           sizeof(struct vmbus_channel_gpadl_body);
 294                 pfncount = pfnsize / sizeof(u64);
 295
 296                 /* fill in the body */
 297                 while (pfnleft) {
 298                         if (pfnleft > pfncount)
 299                                 pfncurr = pfncount;
 300                         else
 301                                 pfncurr = pfnleft;
 302
 303                         msgsize = sizeof(struct vmbus_channel_msginfo) +
 304                                   sizeof(struct vmbus_channel_gpadl_body) +
 305                                   pfncurr * sizeof(u64);
 306                         msgbody = kzalloc(msgsize, GFP_KERNEL);
 307
 308                         if (!msgbody) {
 309                                 struct vmbus_channel_msginfo *pos = NULL;
 310                                 struct vmbus_channel_msginfo *tmp = NULL;
 311                                 /*
 312                                  * Free up all the allocated messages.
 313                                  */
 314                                 list_for_each_entry_safe(pos, tmp,
 315                                         &msgheader->submsglist,
 316                                         msglistentry) {
 317
 318                                         list_del(&pos->msglistentry);
 319                                         kfree(pos);
 320                                 }
 321
 322                                 goto nomem;
 323                         }
 324
 325                         msgbody->msgsize = msgsize;
 326                         gpadl_body =
 327                                 (struct vmbus_channel_gpadl_body *)msgbody->msg;
 328
 329                         /*
 330                          * Gpadl is u32 and we are using a pointer which could
 331                          * be 64-bit
 332                          * This is governed by the guest/host protocol and
 333                          * so the hypervisor gurantees that this is ok.
 334                          */
 335                         for (i = 0; i < pfncurr; i++)
 336                                 gpadl_body->pfn[i] = slow_virt_to_phys(
 337                                         kbuffer + PAGE_SIZE * (pfnsum + i)) >>
 338                                         PAGE_SHIFT;
 339
 340                         /* add to msg header */
 341                         list_add_tail(&msgbody->msglistentry,
 342                                       &msgheader->submsglist);
 343                         pfnsum += pfncurr;
 344                         pfnleft -= pfncurr;
 345                 }
 346         } else {
 347                 /* everything fits in a header */
 348                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 349                           sizeof(struct vmbus_channel_gpadl_header) +
 350                           sizeof(struct gpa_range) + pagecount * sizeof(u64);
 351                 msgheader = kzalloc(msgsize, GFP_KERNEL);
 352                 if (msgheader == NULL)
 353                         goto nomem;
 354
 355                 INIT_LIST_HEAD(&msgheader->submsglist);
 356                 msgheader->msgsize = msgsize;
 357
 358                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 359                         msgheader->msg;
 360                 gpadl_header->rangecount = 1;
 361                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 362                                          pagecount * sizeof(u64);
 363                 gpadl_header->range[0].byte_offset = 0;
 364                 gpadl_header->range[0].byte_count = size;
 365                 for (i = 0; i < pagecount; i++)
 366                         gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
 367                                 kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 368
 369                 *msginfo = msgheader;
 370         }
 371
 372         return 0;
 373 nomem:
 374         kfree(msgheader);
 375         kfree(msgbody);
 376         return -ENOMEM;
 377 }
 378
 379 /*
 380  * vmbus_establish_gpadl - Estabish a GPADL for the specified buffer
 381  *
 382  * @channel: a channel
 383  * @kbuffer: from kmalloc or vmalloc
 384  * @size: page-size multiple
 385  * @gpadl_handle: some funky thing
 386  */
 387 int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
 388                                u32 size, u32 *gpadl_handle)
 389 {
 390         struct vmbus_channel_gpadl_header *gpadlmsg;
 391         struct vmbus_channel_gpadl_body *gpadl_body;
 392         struct vmbus_channel_msginfo *msginfo = NULL;
 393         struct vmbus_channel_msginfo *submsginfo, *tmp;
 394         struct list_head *curr;
 395         u32 next_gpadl_handle;
 396         unsigned long flags;
 397         int ret = 0;
 398
 399         next_gpadl_handle =
 400                 (atomic_inc_return(&vmbus_connection.next_gpadl_handle) - 1);
 401
 402         ret = create_gpadl_header(kbuffer, size, &msginfo);
 403         if (ret)
 404                 return ret;
 405
 406         init_completion(&msginfo->waitevent);
 407
 408         gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
 409         gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
 410         gpadlmsg->child_relid = channel->offermsg.child_relid;
 411         gpadlmsg->gpadl = next_gpadl_handle;
 412
 413
 414         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 415         list_add_tail(&msginfo->msglistentry,
 416                       &vmbus_connection.chn_msg_list);
 417
 418         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 419
 420         ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize -
 421                                sizeof(*msginfo));
 422         if (ret != 0)
 423                 goto cleanup;
 424
 425         list_for_each(curr, &msginfo->submsglist) {
 426                 submsginfo = (struct vmbus_channel_msginfo *)curr;
 427                 gpadl_body =
 428                         (struct vmbus_channel_gpadl_body *)submsginfo->msg;
 429
 430                 gpadl_body->header.msgtype =
 431                         CHANNELMSG_GPADL_BODY;
 432                 gpadl_body->gpadl = next_gpadl_handle;
 433
 434                 ret = vmbus_post_msg(gpadl_body,
 435                                      submsginfo->msgsize -
 436                                      sizeof(*submsginfo));
 437                 if (ret != 0)
 438                         goto cleanup;
 439
 440         }
 441         wait_for_completion(&msginfo->waitevent);
 442
 443         /* At this point, we received the gpadl created msg */
 444         *gpadl_handle = gpadlmsg->gpadl;
 445
 446 cleanup:
 447         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 448         list_del(&msginfo->msglistentry);
 449         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 450         list_for_each_entry_safe(submsginfo, tmp, &msginfo->submsglist,
 451                                  msglistentry) {
 452                 kfree(submsginfo);
 453         }
 454
 455         kfree(msginfo);
 456         return ret;
 457 }
 458 EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
 459
 460 /*
 461  * vmbus_teardown_gpadl -Teardown the specified GPADL handle
 462  */
 463 int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
 464 {
 465         struct vmbus_channel_gpadl_teardown *msg;
 466         struct vmbus_channel_msginfo *info;
 467         unsigned long flags;
 468         int ret;
 469
 470         info = kmalloc(sizeof(*info) +
 471                        sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
 472         if (!info)
 473                 return -ENOMEM;
 474
 475         init_completion(&info->waitevent);
 476
 477         msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
 478
 479         msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
 480         msg->child_relid = channel->offermsg.child_relid;
 481         msg->gpadl = gpadl_handle;
 482
 483         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 484         list_add_tail(&info->msglistentry,
 485                       &vmbus_connection.chn_msg_list);
 486         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 487         ret = vmbus_post_msg(msg,
 488                                sizeof(struct vmbus_channel_gpadl_teardown));
 489
 490         if (ret)
 491                 goto post_msg_err;
 492
 493         wait_for_completion(&info->waitevent);
 494
 495 post_msg_err:
 496         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 497         list_del(&info->msglistentry);
 498         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 499
 500         kfree(info);
 501         return ret;
 502 }
 503 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
 504
 505 static void reset_channel_cb(void *arg)
 506 {
 507         struct vmbus_channel *channel = arg;
 508
 509         channel->onchannel_callback = NULL;
 510 }
 511
 512 static int vmbus_close_internal(struct vmbus_channel *channel)
 513 {
 514         struct vmbus_channel_close_channel *msg;
 515         int ret;
 516
 517         /*
 518          * process_chn_event(), running in the tasklet, can race
 519          * with vmbus_close_internal() in the case of SMP guest, e.g., when
 520          * the former is accessing channel->inbound.ring_buffer, the latter
 521          * could be freeing the ring_buffer pages.
 522          *
 523          * To resolve the race, we can serialize them by disabling the
 524          * tasklet when the latter is running here.
 525          */
 526         hv_event_tasklet_disable(channel);
 527
 528         /*
 529          * In case a device driver's probe() fails (e.g.,
 530          * util_probe() -> vmbus_open() returns -ENOMEM) and the device is
 531          * rescinded later (e.g., we dynamically disble an Integrated Service
 532          * in Hyper-V Manager), the driver's remove() invokes vmbus_close():
 533          * here we should skip most of the below cleanup work.
 534          */
 535         if (channel->state != CHANNEL_OPENED_STATE) {
 536                 ret = -EINVAL;
 537                 goto out;
 538         }
 539
 540         channel->state = CHANNEL_OPEN_STATE;
 541         channel->sc_creation_callback = NULL;
 542         /* Stop callback and cancel the timer asap */
 543         if (channel->target_cpu != get_cpu()) {
 544                 put_cpu();
 545                 smp_call_function_single(channel->target_cpu, reset_channel_cb,
 546                                          channel, true);
 547         } else {
 548                 reset_channel_cb(channel);
 549                 put_cpu();
 550         }
 551
 552         /* Send a closing message */
 553
 554         msg = &channel->close_msg.msg;
 555
 556         msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
 557         msg->child_relid = channel->offermsg.child_relid;
 558
 559         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel));
 560
 561         if (ret) {
 562                 pr_err("Close failed: close post msg return is %d\n", ret);
 563                 /*
 564                  * If we failed to post the close msg,
 565                  * it is perhaps better to leak memory.
 566                  */
 567                 goto out;
 568         }
 569
 570         /* Tear down the gpadl for the channel's ring buffer */
 571         if (channel->ringbuffer_gpadlhandle) {
 572                 ret = vmbus_teardown_gpadl(channel,
 573                                            channel->ringbuffer_gpadlhandle);
 574                 if (ret) {
 575                         pr_err("Close failed: teardown gpadl return %d\n", ret);
 576                         /*
 577                          * If we failed to teardown gpadl,
 578                          * it is perhaps better to leak memory.
 579                          */
 580                         goto out;
 581                 }
 582         }
 583
 584         /* Cleanup the ring buffers for this channel */
 585         hv_ringbuffer_cleanup(&channel->outbound);
 586         hv_ringbuffer_cleanup(&channel->inbound);
 587
 588         free_pages((unsigned long)channel->ringbuffer_pages,
 589                 get_order(channel->ringbuffer_pagecount * PAGE_SIZE));
 590
 591 out:
 592         hv_event_tasklet_enable(channel);
 593
 594         return ret;
 595 }
 596
 597 /*
 598  * vmbus_close - Close the specified channel
 599  */
 600 void vmbus_close(struct vmbus_channel *channel)
 601 {
 602         struct list_head *cur, *tmp;
 603         struct vmbus_channel *cur_channel;
 604
 605         if (channel->primary_channel != NULL) {
 606                 /*
 607                  * We will only close sub-channels when
 608                  * the primary is closed.
 609                  */
 610                 return;
 611         }
 612         /*
 613          * Close all the sub-channels first and then close the
 614          * primary channel.
 615          */
 616         list_for_each_safe(cur, tmp, &channel->sc_list) {
 617                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 618                 if (cur_channel->state != CHANNEL_OPENED_STATE)
 619                         continue;
 620                 vmbus_close_internal(cur_channel);
 621         }
 622         /*
 623          * Now close the primary.
 624          */
 625         vmbus_close_internal(channel);
 626 }
 627 EXPORT_SYMBOL_GPL(vmbus_close);
 628
 629 int vmbus_sendpacket_ctl(struct vmbus_channel *channel, void *buffer,
 630                            u32 bufferlen, u64 requestid,
 631                            enum vmbus_packet_type type, u32 flags, bool kick_q)
 632 {
 633         struct vmpacket_descriptor desc;
 634         u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
 635         u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 636         struct kvec bufferlist[3];
 637         u64 aligned_data = 0;
 638         int ret;
 639         bool signal = false;
 640         bool lock = channel->acquire_ring_lock;
 641         int num_vecs = ((bufferlen != 0) ? 3 : 1);
 642
 643
 644         /* Setup the descriptor */
 645         desc.type = type; /* VmbusPacketTypeDataInBand; */
 646         desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
 647         /* in 8-bytes granularity */
 648         desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3;
 649         desc.len8 = (u16)(packetlen_aligned >> 3);
 650         desc.trans_id = requestid;
 651
 652         bufferlist[0].iov_base = &desc;
 653         bufferlist[0].iov_len = sizeof(struct vmpacket_descriptor);
 654         bufferlist[1].iov_base = buffer;
 655         bufferlist[1].iov_len = bufferlen;
 656         bufferlist[2].iov_base = &aligned_data;
 657         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 658
 659         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, num_vecs,
 660                                   &signal, lock, channel->signal_policy);
 661
 662         /*
 663          * Signalling the host is conditional on many factors:
 664          * 1. The ring state changed from being empty to non-empty.
 665          *    This is tracked by the variable "signal".
 666          * 2. The variable kick_q tracks if more data will be placed
 667          *    on the ring. We will not signal if more data is
 668          *    to be placed.
 669          *
 670          * Based on the channel signal state, we will decide
 671          * which signaling policy will be applied.
 672          *
 673          * If we cannot write to the ring-buffer; signal the host
 674          * even if we may not have written anything. This is a rare
 675          * enough condition that it should not matter.
 676          * NOTE: in this case, the hvsock channel is an exception, because
 677          * it looks the host side's hvsock implementation has a throttling
 678          * mechanism which can hurt the performance otherwise.
 679          */
 680
 681         if (((ret == 0) && kick_q && signal) ||
 682             (ret && !is_hvsock_channel(channel)))
 683                 vmbus_setevent(channel);
 684
 685         return ret;
 686 }
 687 EXPORT_SYMBOL(vmbus_sendpacket_ctl);
 688
 689 /**
 690  * vmbus_sendpacket() - Send the specified buffer on the given channel
 691  * @channel: Pointer to vmbus_channel structure.
 692  * @buffer: Pointer to the buffer you want to receive the data into.
 693  * @bufferlen: Maximum size of what the the buffer will hold
 694  * @requestid: Identifier of the request
 695  * @type: Type of packet that is being send e.g. negotiate, time
 696  * packet etc.
 697  *
 698  * Sends data in @buffer directly to hyper-v via the vmbus
 699  * This will send the data unparsed to hyper-v.
 700  *
 701  * Mainly used by Hyper-V drivers.
 702  */
 703 int vmbus_sendpacket(struct vmbus_channel *channel, void *buffer,
 704                            u32 bufferlen, u64 requestid,
 705                            enum vmbus_packet_type type, u32 flags)
 706 {
 707         return vmbus_sendpacket_ctl(channel, buffer, bufferlen, requestid,
 708                                     type, flags, true);
 709 }
 710 EXPORT_SYMBOL(vmbus_sendpacket);
 711
 712 /*
 713  * vmbus_sendpacket_pagebuffer_ctl - Send a range of single-page buffer
 714  * packets using a GPADL Direct packet type. This interface allows you
 715  * to control notifying the host. This will be useful for sending
 716  * batched data. Also the sender can control the send flags
 717  * explicitly.
 718  */
 719 int vmbus_sendpacket_pagebuffer_ctl(struct vmbus_channel *channel,
 720                                      struct hv_page_buffer pagebuffers[],
 721                                      u32 pagecount, void *buffer, u32 bufferlen,
 722                                      u64 requestid,
 723                                      u32 flags,
 724                                      bool kick_q)
 725 {
 726         int ret;
 727         int i;
 728         struct vmbus_channel_packet_page_buffer desc;
 729         u32 descsize;
 730         u32 packetlen;
 731         u32 packetlen_aligned;
 732         struct kvec bufferlist[3];
 733         u64 aligned_data = 0;
 734         bool signal = false;
 735         bool lock = channel->acquire_ring_lock;
 736
 737         if (pagecount > MAX_PAGE_BUFFER_COUNT)
 738                 return -EINVAL;
 739
 740
 741         /*
 742          * Adjust the size down since vmbus_channel_packet_page_buffer is the
 743          * largest size we support
 744          */
 745         descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
 746                           ((MAX_PAGE_BUFFER_COUNT - pagecount) *
 747                           sizeof(struct hv_page_buffer));
 748         packetlen = descsize + bufferlen;
 749         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 750
 751         /* Setup the descriptor */
 752         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
 753         desc.flags = flags;
 754         desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
 755         desc.length8 = (u16)(packetlen_aligned >> 3);
 756         desc.transactionid = requestid;
 757         desc.rangecount = pagecount;
 758
 759         for (i = 0; i < pagecount; i++) {
 760                 desc.range[i].len = pagebuffers[i].len;
 761                 desc.range[i].offset = pagebuffers[i].offset;
 762                 desc.range[i].pfn        = pagebuffers[i].pfn;
 763         }
 764
 765         bufferlist[0].iov_base = &desc;
 766         bufferlist[0].iov_len = descsize;
 767         bufferlist[1].iov_base = buffer;
 768         bufferlist[1].iov_len = bufferlen;
 769         bufferlist[2].iov_base = &aligned_data;
 770         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 771
 772         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3,
 773                                   &signal, lock, channel->signal_policy);
 774
 775         /*
 776          * Signalling the host is conditional on many factors:
 777          * 1. The ring state changed from being empty to non-empty.
 778          *    This is tracked by the variable "signal".
 779          * 2. The variable kick_q tracks if more data will be placed
 780          *    on the ring. We will not signal if more data is
 781          *    to be placed.
 782          *
 783          * Based on the channel signal state, we will decide
 784          * which signaling policy will be applied.
 785          *
 786          * If we cannot write to the ring-buffer; signal the host
 787          * even if we may not have written anything. This is a rare
 788          * enough condition that it should not matter.
 789          */
 790
 791         if (((ret == 0) && kick_q && signal) || (ret))
 792                 vmbus_setevent(channel);
 793
 794         return ret;
 795 }
 796 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer_ctl);
 797
 798 /*
 799  * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
 800  * packets using a GPADL Direct packet type.
 801  */
 802 int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
 803                                      struct hv_page_buffer pagebuffers[],
 804                                      u32 pagecount, void *buffer, u32 bufferlen,
 805                                      u64 requestid)
 806 {
 807         u32 flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 808         return vmbus_sendpacket_pagebuffer_ctl(channel, pagebuffers, pagecount,
 809                                                buffer, bufferlen, requestid,
 810                                                flags, true);
 811
 812 }
 813 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
 814
 815 /*
 816  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
 817  * using a GPADL Direct packet type.
 818  * The buffer includes the vmbus descriptor.
 819  */
 820 int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
 821                               struct vmbus_packet_mpb_array *desc,
 822                               u32 desc_size,
 823                               void *buffer, u32 bufferlen, u64 requestid)
 824 {
 825         int ret;
 826         u32 packetlen;
 827         u32 packetlen_aligned;
 828         struct kvec bufferlist[3];
 829         u64 aligned_data = 0;
 830         bool signal = false;
 831         bool lock = channel->acquire_ring_lock;
 832
 833         packetlen = desc_size + bufferlen;
 834         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 835
 836         /* Setup the descriptor */
 837         desc->type = VM_PKT_DATA_USING_GPA_DIRECT;
 838         desc->flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 839         desc->dataoffset8 = desc_size >> 3; /* in 8-bytes grandularity */
 840         desc->length8 = (u16)(packetlen_aligned >> 3);
 841         desc->transactionid = requestid;
 842         desc->rangecount = 1;
 843
 844         bufferlist[0].iov_base = desc;
 845         bufferlist[0].iov_len = desc_size;
 846         bufferlist[1].iov_base = buffer;
 847         bufferlist[1].iov_len = bufferlen;
 848         bufferlist[2].iov_base = &aligned_data;
 849         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 850
 851         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3,
 852                                   &signal, lock, channel->signal_policy);
 853
 854         if (ret == 0 && signal)
 855                 vmbus_setevent(channel);
 856
 857         return ret;
 858 }
 859 EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc);
 860
 861 /*
 862  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
 863  * using a GPADL Direct packet type.
 864  */
 865 int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
 866                                 struct hv_multipage_buffer *multi_pagebuffer,
 867                                 void *buffer, u32 bufferlen, u64 requestid)
 868 {
 869         int ret;
 870         struct vmbus_channel_packet_multipage_buffer desc;
 871         u32 descsize;
 872         u32 packetlen;
 873         u32 packetlen_aligned;
 874         struct kvec bufferlist[3];
 875         u64 aligned_data = 0;
 876         bool signal = false;
 877         bool lock = channel->acquire_ring_lock;
 878         u32 pfncount = NUM_PAGES_SPANNED(multi_pagebuffer->offset,
 879                                          multi_pagebuffer->len);
 880
 881         if (pfncount > MAX_MULTIPAGE_BUFFER_COUNT)
 882                 return -EINVAL;
 883
 884         /*
 885          * Adjust the size down since vmbus_channel_packet_multipage_buffer is
 886          * the largest size we support
 887          */
 888         descsize = sizeof(struct vmbus_channel_packet_multipage_buffer) -
 889                           ((MAX_MULTIPAGE_BUFFER_COUNT - pfncount) *
 890                           sizeof(u64));
 891         packetlen = descsize + bufferlen;
 892         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 893
 894
 895         /* Setup the descriptor */
 896         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
 897         desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 898         desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
 899         desc.length8 = (u16)(packetlen_aligned >> 3);
 900         desc.transactionid = requestid;
 901         desc.rangecount = 1;
 902
 903         desc.range.len = multi_pagebuffer->len;
 904         desc.range.offset = multi_pagebuffer->offset;
 905
 906         memcpy(desc.range.pfn_array, multi_pagebuffer->pfn_array,
 907                pfncount * sizeof(u64));
 908
 909         bufferlist[0].iov_base = &desc;
 910         bufferlist[0].iov_len = descsize;
 911         bufferlist[1].iov_base = buffer;
 912         bufferlist[1].iov_len = bufferlen;
 913         bufferlist[2].iov_base = &aligned_data;
 914         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 915
 916         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3,
 917                                   &signal, lock, channel->signal_policy);
 918
 919         if (ret == 0 && signal)
 920                 vmbus_setevent(channel);
 921
 922         return ret;
 923 }
 924 EXPORT_SYMBOL_GPL(vmbus_sendpacket_multipagebuffer);
 925
 926 /**
 927  * vmbus_recvpacket() - Retrieve the user packet on the specified channel
 928  * @channel: Pointer to vmbus_channel structure.
 929  * @buffer: Pointer to the buffer you want to receive the data into.
 930  * @bufferlen: Maximum size of what the the buffer will hold
 931  * @buffer_actual_len: The actual size of the data after it was received
 932  * @requestid: Identifier of the request
 933  *
 934  * Receives directly from the hyper-v vmbus and puts the data it received
 935  * into Buffer. This will receive the data unparsed from hyper-v.
 936  *
 937  * Mainly used by Hyper-V drivers.
 938  */
 939 static inline int
 940 __vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
 941                    u32 bufferlen, u32 *buffer_actual_len, u64 *requestid,
 942                    bool raw)
 943 {
 944         int ret;
 945         bool signal = false;
 946
 947         ret = hv_ringbuffer_read(&channel->inbound, buffer, bufferlen,
 948                                  buffer_actual_len, requestid, &signal, raw);
 949
 950         if (signal)
 951                 vmbus_setevent(channel);
 952
 953         return ret;
 954 }
 955
 956 int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
 957                      u32 bufferlen, u32 *buffer_actual_len,
 958                      u64 *requestid)
 959 {
 960         return __vmbus_recvpacket(channel, buffer, bufferlen,
 961                                   buffer_actual_len, requestid, false);
 962 }
 963 EXPORT_SYMBOL(vmbus_recvpacket);
 964
 965 /*
 966  * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
 967  */
 968 int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
 969                               u32 bufferlen, u32 *buffer_actual_len,
 970                               u64 *requestid)
 971 {
 972         return __vmbus_recvpacket(channel, buffer, bufferlen,
 973                                   buffer_actual_len, requestid, true);
 974 }
 975 EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);