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
  31 #include "hyperv_vmbus.h"
  32
  33 #define NUM_PAGES_SPANNED(addr, len) \
  34 ((PAGE_ALIGN(addr + len) >> PAGE_SHIFT) - (addr >> PAGE_SHIFT))
  35
  36 /*
  37  * vmbus_setevent- Trigger an event notification on the specified
  38  * channel.
  39  */
  40 static void vmbus_setevent(struct vmbus_channel *channel)
  41 {
  42         struct hv_monitor_page *monitorpage;
  43
  44         if (channel->offermsg.monitor_allocated) {
  45                 /* Each u32 represents 32 channels */
  46                 sync_set_bit(channel->offermsg.child_relid & 31,
  47                         (unsigned long *) vmbus_connection.send_int_page +
  48                         (channel->offermsg.child_relid >> 5));
  49
  50                 /* Get the child to parent monitor page */
  51                 monitorpage = vmbus_connection.monitor_pages[1];
  52
  53                 sync_set_bit(channel->monitor_bit,
  54                         (unsigned long *)&monitorpage->trigger_group
  55                                         [channel->monitor_grp].pending);
  56
  57         } else {
  58                 vmbus_set_event(channel);
  59         }
  60 }
  61
  62 /*
  63  * vmbus_open - Open the specified channel.
  64  */
  65 int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
  66                      u32 recv_ringbuffer_size, void *userdata, u32 userdatalen,
  67                      void (*onchannelcallback)(void *context), void *context)
  68 {
  69         struct vmbus_channel_open_channel *open_msg;
  70         struct vmbus_channel_msginfo *open_info = NULL;
  71         void *in, *out;
  72         unsigned long flags;
  73         int ret, t, err = 0;
  74
  75         spin_lock_irqsave(&newchannel->sc_lock, flags);
  76         if (newchannel->state == CHANNEL_OPEN_STATE) {
  77                 newchannel->state = CHANNEL_OPENING_STATE;
  78         } else {
  79                 spin_unlock_irqrestore(&newchannel->sc_lock, flags);
  80                 return -EINVAL;
  81         }
  82         spin_unlock_irqrestore(&newchannel->sc_lock, flags);
  83
  84         newchannel->onchannel_callback = onchannelcallback;
  85         newchannel->channel_callback_context = context;
  86
  87         /* Allocate the ring buffer */
  88         out = (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
  89                 get_order(send_ringbuffer_size + recv_ringbuffer_size));
  90
  91         if (!out)
  92                 return -ENOMEM;
  93
  94
  95         in = (void *)((unsigned long)out + send_ringbuffer_size);
  96
  97         newchannel->ringbuffer_pages = out;
  98         newchannel->ringbuffer_pagecount = (send_ringbuffer_size +
  99                                            recv_ringbuffer_size) >> PAGE_SHIFT;
 100
 101         ret = hv_ringbuffer_init(
 102                 &newchannel->outbound, out, send_ringbuffer_size);
 103
 104         if (ret != 0) {
 105                 err = ret;
 106                 goto error0;
 107         }
 108
 109         ret = hv_ringbuffer_init(
 110                 &newchannel->inbound, in, recv_ringbuffer_size);
 111         if (ret != 0) {
 112                 err = ret;
 113                 goto error0;
 114         }
 115
 116
 117         /* Establish the gpadl for the ring buffer */
 118         newchannel->ringbuffer_gpadlhandle = 0;
 119
 120         ret = vmbus_establish_gpadl(newchannel,
 121                                          newchannel->outbound.ring_buffer,
 122                                          send_ringbuffer_size +
 123                                          recv_ringbuffer_size,
 124                                          &newchannel->ringbuffer_gpadlhandle);
 125
 126         if (ret != 0) {
 127                 err = ret;
 128                 goto error0;
 129         }
 130
 131         /* Create and init the channel open message */
 132         open_info = kmalloc(sizeof(*open_info) +
 133                            sizeof(struct vmbus_channel_open_channel),
 134                            GFP_KERNEL);
 135         if (!open_info) {
 136                 err = -ENOMEM;
 137                 goto error0;
 138         }
 139
 140         init_completion(&open_info->waitevent);
 141
 142         open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
 143         open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
 144         open_msg->openid = newchannel->offermsg.child_relid;
 145         open_msg->child_relid = newchannel->offermsg.child_relid;
 146         open_msg->ringbuffer_gpadlhandle = newchannel->ringbuffer_gpadlhandle;
 147         open_msg->downstream_ringbuffer_pageoffset = send_ringbuffer_size >>
 148                                                   PAGE_SHIFT;
 149         open_msg->target_vp = newchannel->target_vp;
 150
 151         if (userdatalen > MAX_USER_DEFINED_BYTES) {
 152                 err = -EINVAL;
 153                 goto error0;
 154         }
 155
 156         if (userdatalen)
 157                 memcpy(open_msg->userdata, userdata, userdatalen);
 158
 159         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 160         list_add_tail(&open_info->msglistentry,
 161                       &vmbus_connection.chn_msg_list);
 162         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 163
 164         ret = vmbus_post_msg(open_msg,
 165                                sizeof(struct vmbus_channel_open_channel));
 166
 167         if (ret != 0)
 168                 goto error1;
 169
 170         t = wait_for_completion_timeout(&open_info->waitevent, 5*HZ);
 171         if (t == 0) {
 172                 err = -ETIMEDOUT;
 173                 goto error1;
 174         }
 175
 176
 177         if (open_info->response.open_result.status)
 178                 err = open_info->response.open_result.status;
 179
 180         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 181         list_del(&open_info->msglistentry);
 182         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 183
 184         if (err == 0)
 185                 newchannel->state = CHANNEL_OPENED_STATE;
 186
 187         kfree(open_info);
 188         return err;
 189
 190 error1:
 191         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 192         list_del(&open_info->msglistentry);
 193         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 194
 195 error0:
 196         free_pages((unsigned long)out,
 197                 get_order(send_ringbuffer_size + recv_ringbuffer_size));
 198         kfree(open_info);
 199         return err;
 200 }
 201 EXPORT_SYMBOL_GPL(vmbus_open);
 202
 203 /*
 204  * create_gpadl_header - Creates a gpadl for the specified buffer
 205  */
 206 static int create_gpadl_header(void *kbuffer, u32 size,
 207                                          struct vmbus_channel_msginfo **msginfo,
 208                                          u32 *messagecount)
 209 {
 210         int i;
 211         int pagecount;
 212         unsigned long long pfn;
 213         struct vmbus_channel_gpadl_header *gpadl_header;
 214         struct vmbus_channel_gpadl_body *gpadl_body;
 215         struct vmbus_channel_msginfo *msgheader;
 216         struct vmbus_channel_msginfo *msgbody = NULL;
 217         u32 msgsize;
 218
 219         int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
 220
 221         pagecount = size >> PAGE_SHIFT;
 222         pfn = virt_to_phys(kbuffer) >> PAGE_SHIFT;
 223
 224         /* do we need a gpadl body msg */
 225         pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 226                   sizeof(struct vmbus_channel_gpadl_header) -
 227                   sizeof(struct gpa_range);
 228         pfncount = pfnsize / sizeof(u64);
 229
 230         if (pagecount > pfncount) {
 231                 /* we need a gpadl body */
 232                 /* fill in the header */
 233                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 234                           sizeof(struct vmbus_channel_gpadl_header) +
 235                           sizeof(struct gpa_range) + pfncount * sizeof(u64);
 236                 msgheader =  kzalloc(msgsize, GFP_KERNEL);
 237                 if (!msgheader)
 238                         goto nomem;
 239
 240                 INIT_LIST_HEAD(&msgheader->submsglist);
 241                 msgheader->msgsize = msgsize;
 242
 243                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 244                         msgheader->msg;
 245                 gpadl_header->rangecount = 1;
 246                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 247                                          pagecount * sizeof(u64);
 248                 gpadl_header->range[0].byte_offset = 0;
 249                 gpadl_header->range[0].byte_count = size;
 250                 for (i = 0; i < pfncount; i++)
 251                         gpadl_header->range[0].pfn_array[i] = pfn+i;
 252                 *msginfo = msgheader;
 253                 *messagecount = 1;
 254
 255                 pfnsum = pfncount;
 256                 pfnleft = pagecount - pfncount;
 257
 258                 /* how many pfns can we fit */
 259                 pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 260                           sizeof(struct vmbus_channel_gpadl_body);
 261                 pfncount = pfnsize / sizeof(u64);
 262
 263                 /* fill in the body */
 264                 while (pfnleft) {
 265                         if (pfnleft > pfncount)
 266                                 pfncurr = pfncount;
 267                         else
 268                                 pfncurr = pfnleft;
 269
 270                         msgsize = sizeof(struct vmbus_channel_msginfo) +
 271                                   sizeof(struct vmbus_channel_gpadl_body) +
 272                                   pfncurr * sizeof(u64);
 273                         msgbody = kzalloc(msgsize, GFP_KERNEL);
 274
 275                         if (!msgbody) {
 276                                 struct vmbus_channel_msginfo *pos = NULL;
 277                                 struct vmbus_channel_msginfo *tmp = NULL;
 278                                 /*
 279                                  * Free up all the allocated messages.
 280                                  */
 281                                 list_for_each_entry_safe(pos, tmp,
 282                                         &msgheader->submsglist,
 283                                         msglistentry) {
 284
 285                                         list_del(&pos->msglistentry);
 286                                         kfree(pos);
 287                                 }
 288
 289                                 goto nomem;
 290                         }
 291
 292                         msgbody->msgsize = msgsize;
 293                         (*messagecount)++;
 294                         gpadl_body =
 295                                 (struct vmbus_channel_gpadl_body *)msgbody->msg;
 296
 297                         /*
 298                          * Gpadl is u32 and we are using a pointer which could
 299                          * be 64-bit
 300                          * This is governed by the guest/host protocol and
 301                          * so the hypervisor gurantees that this is ok.
 302                          */
 303                         for (i = 0; i < pfncurr; i++)
 304                                 gpadl_body->pfn[i] = pfn + pfnsum + i;
 305
 306                         /* add to msg header */
 307                         list_add_tail(&msgbody->msglistentry,
 308                                       &msgheader->submsglist);
 309                         pfnsum += pfncurr;
 310                         pfnleft -= pfncurr;
 311                 }
 312         } else {
 313                 /* everything fits in a header */
 314                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 315                           sizeof(struct vmbus_channel_gpadl_header) +
 316                           sizeof(struct gpa_range) + pagecount * sizeof(u64);
 317                 msgheader = kzalloc(msgsize, GFP_KERNEL);
 318                 if (msgheader == NULL)
 319                         goto nomem;
 320                 msgheader->msgsize = msgsize;
 321
 322                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 323                         msgheader->msg;
 324                 gpadl_header->rangecount = 1;
 325                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 326                                          pagecount * sizeof(u64);
 327                 gpadl_header->range[0].byte_offset = 0;
 328                 gpadl_header->range[0].byte_count = size;
 329                 for (i = 0; i < pagecount; i++)
 330                         gpadl_header->range[0].pfn_array[i] = pfn+i;
 331
 332                 *msginfo = msgheader;
 333                 *messagecount = 1;
 334         }
 335
 336         return 0;
 337 nomem:
 338         kfree(msgheader);
 339         kfree(msgbody);
 340         return -ENOMEM;
 341 }
 342
 343 /*
 344  * vmbus_establish_gpadl - Estabish a GPADL for the specified buffer
 345  *
 346  * @channel: a channel
 347  * @kbuffer: from kmalloc
 348  * @size: page-size multiple
 349  * @gpadl_handle: some funky thing
 350  */
 351 int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
 352                                u32 size, u32 *gpadl_handle)
 353 {
 354         struct vmbus_channel_gpadl_header *gpadlmsg;
 355         struct vmbus_channel_gpadl_body *gpadl_body;
 356         struct vmbus_channel_msginfo *msginfo = NULL;
 357         struct vmbus_channel_msginfo *submsginfo;
 358         u32 msgcount;
 359         struct list_head *curr;
 360         u32 next_gpadl_handle;
 361         unsigned long flags;
 362         int ret = 0;
 363         int t;
 364
 365         next_gpadl_handle = atomic_read(&vmbus_connection.next_gpadl_handle);
 366         atomic_inc(&vmbus_connection.next_gpadl_handle);
 367
 368         ret = create_gpadl_header(kbuffer, size, &msginfo, &msgcount);
 369         if (ret)
 370                 return ret;
 371
 372         init_completion(&msginfo->waitevent);
 373
 374         gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
 375         gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
 376         gpadlmsg->child_relid = channel->offermsg.child_relid;
 377         gpadlmsg->gpadl = next_gpadl_handle;
 378
 379
 380         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 381         list_add_tail(&msginfo->msglistentry,
 382                       &vmbus_connection.chn_msg_list);
 383
 384         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 385
 386         ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize -
 387                                sizeof(*msginfo));
 388         if (ret != 0)
 389                 goto cleanup;
 390
 391         if (msgcount > 1) {
 392                 list_for_each(curr, &msginfo->submsglist) {
 393
 394                         submsginfo = (struct vmbus_channel_msginfo *)curr;
 395                         gpadl_body =
 396                              (struct vmbus_channel_gpadl_body *)submsginfo->msg;
 397
 398                         gpadl_body->header.msgtype =
 399                                 CHANNELMSG_GPADL_BODY;
 400                         gpadl_body->gpadl = next_gpadl_handle;
 401
 402                         ret = vmbus_post_msg(gpadl_body,
 403                                                submsginfo->msgsize -
 404                                                sizeof(*submsginfo));
 405                         if (ret != 0)
 406                                 goto cleanup;
 407
 408                 }
 409         }
 410         t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
 411         BUG_ON(t == 0);
 412
 413
 414         /* At this point, we received the gpadl created msg */
 415         *gpadl_handle = gpadlmsg->gpadl;
 416
 417 cleanup:
 418         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 419         list_del(&msginfo->msglistentry);
 420         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 421
 422         kfree(msginfo);
 423         return ret;
 424 }
 425 EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
 426
 427 /*
 428  * vmbus_teardown_gpadl -Teardown the specified GPADL handle
 429  */
 430 int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
 431 {
 432         struct vmbus_channel_gpadl_teardown *msg;
 433         struct vmbus_channel_msginfo *info;
 434         unsigned long flags;
 435         int ret, t;
 436
 437         info = kmalloc(sizeof(*info) +
 438                        sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
 439         if (!info)
 440                 return -ENOMEM;
 441
 442         init_completion(&info->waitevent);
 443
 444         msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
 445
 446         msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
 447         msg->child_relid = channel->offermsg.child_relid;
 448         msg->gpadl = gpadl_handle;
 449
 450         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 451         list_add_tail(&info->msglistentry,
 452                       &vmbus_connection.chn_msg_list);
 453         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 454         ret = vmbus_post_msg(msg,
 455                                sizeof(struct vmbus_channel_gpadl_teardown));
 456
 457         BUG_ON(ret != 0);
 458         t = wait_for_completion_timeout(&info->waitevent, 5*HZ);
 459         BUG_ON(t == 0);
 460
 461         /* Received a torndown response */
 462         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 463         list_del(&info->msglistentry);
 464         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 465
 466         kfree(info);
 467         return ret;
 468 }
 469 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
 470
 471 static void vmbus_close_internal(struct vmbus_channel *channel)
 472 {
 473         struct vmbus_channel_close_channel *msg;
 474         int ret;
 475         unsigned long flags;
 476
 477         channel->state = CHANNEL_OPEN_STATE;
 478         channel->sc_creation_callback = NULL;
 479         /* Stop callback and cancel the timer asap */
 480         spin_lock_irqsave(&channel->inbound_lock, flags);
 481         channel->onchannel_callback = NULL;
 482         spin_unlock_irqrestore(&channel->inbound_lock, flags);
 483
 484         /* Send a closing message */
 485
 486         msg = &channel->close_msg.msg;
 487
 488         msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
 489         msg->child_relid = channel->offermsg.child_relid;
 490
 491         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel));
 492
 493         BUG_ON(ret != 0);
 494         /* Tear down the gpadl for the channel's ring buffer */
 495         if (channel->ringbuffer_gpadlhandle)
 496                 vmbus_teardown_gpadl(channel,
 497                                           channel->ringbuffer_gpadlhandle);
 498
 499         /* Cleanup the ring buffers for this channel */
 500         hv_ringbuffer_cleanup(&channel->outbound);
 501         hv_ringbuffer_cleanup(&channel->inbound);
 502
 503         free_pages((unsigned long)channel->ringbuffer_pages,
 504                 get_order(channel->ringbuffer_pagecount * PAGE_SIZE));
 505
 506
 507 }
 508
 509 /*
 510  * vmbus_close - Close the specified channel
 511  */
 512 void vmbus_close(struct vmbus_channel *channel)
 513 {
 514         struct list_head *cur, *tmp;
 515         struct vmbus_channel *cur_channel;
 516
 517         if (channel->primary_channel != NULL) {
 518                 /*
 519                  * We will only close sub-channels when
 520                  * the primary is closed.
 521                  */
 522                 return;
 523         }
 524         /*
 525          * Close all the sub-channels first and then close the
 526          * primary channel.
 527          */
 528         list_for_each_safe(cur, tmp, &channel->sc_list) {
 529                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 530                 if (cur_channel->state != CHANNEL_OPENED_STATE)
 531                         continue;
 532                 vmbus_close_internal(cur_channel);
 533         }
 534         /*
 535          * Now close the primary.
 536          */
 537         vmbus_close_internal(channel);
 538 }
 539 EXPORT_SYMBOL_GPL(vmbus_close);
 540
 541 /**
 542  * vmbus_sendpacket() - Send the specified buffer on the given channel
 543  * @channel: Pointer to vmbus_channel structure.
 544  * @buffer: Pointer to the buffer you want to receive the data into.
 545  * @bufferlen: Maximum size of what the the buffer will hold
 546  * @requestid: Identifier of the request
 547  * @type: Type of packet that is being send e.g. negotiate, time
 548  * packet etc.
 549  *
 550  * Sends data in @buffer directly to hyper-v via the vmbus
 551  * This will send the data unparsed to hyper-v.
 552  *
 553  * Mainly used by Hyper-V drivers.
 554  */
 555 int vmbus_sendpacket(struct vmbus_channel *channel, const void *buffer,
 556                            u32 bufferlen, u64 requestid,
 557                            enum vmbus_packet_type type, u32 flags)
 558 {
 559         struct vmpacket_descriptor desc;
 560         u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
 561         u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 562         struct scatterlist bufferlist[3];
 563         u64 aligned_data = 0;
 564         int ret;
 565         bool signal = false;
 566
 567
 568         /* Setup the descriptor */
 569         desc.type = type; /* VmbusPacketTypeDataInBand; */
 570         desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
 571         /* in 8-bytes granularity */
 572         desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3;
 573         desc.len8 = (u16)(packetlen_aligned >> 3);
 574         desc.trans_id = requestid;
 575
 576         sg_init_table(bufferlist, 3);
 577         sg_set_buf(&bufferlist[0], &desc, sizeof(struct vmpacket_descriptor));
 578         sg_set_buf(&bufferlist[1], buffer, bufferlen);
 579         sg_set_buf(&bufferlist[2], &aligned_data,
 580                    packetlen_aligned - packetlen);
 581
 582         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
 583
 584         if (ret == 0 && signal)
 585                 vmbus_setevent(channel);
 586
 587         return ret;
 588 }
 589 EXPORT_SYMBOL(vmbus_sendpacket);
 590
 591 /*
 592  * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
 593  * packets using a GPADL Direct packet type.
 594  */
 595 int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
 596                                      struct hv_page_buffer pagebuffers[],
 597                                      u32 pagecount, void *buffer, u32 bufferlen,
 598                                      u64 requestid)
 599 {
 600         int ret;
 601         int i;
 602         struct vmbus_channel_packet_page_buffer desc;
 603         u32 descsize;
 604         u32 packetlen;
 605         u32 packetlen_aligned;
 606         struct scatterlist bufferlist[3];
 607         u64 aligned_data = 0;
 608         bool signal = false;
 609
 610         if (pagecount > MAX_PAGE_BUFFER_COUNT)
 611                 return -EINVAL;
 612
 613
 614         /*
 615          * Adjust the size down since vmbus_channel_packet_page_buffer is the
 616          * largest size we support
 617          */
 618         descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
 619                           ((MAX_PAGE_BUFFER_COUNT - pagecount) *
 620                           sizeof(struct hv_page_buffer));
 621         packetlen = descsize + bufferlen;
 622         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 623
 624         /* Setup the descriptor */
 625         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
 626         desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 627         desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
 628         desc.length8 = (u16)(packetlen_aligned >> 3);
 629         desc.transactionid = requestid;
 630         desc.rangecount = pagecount;
 631
 632         for (i = 0; i < pagecount; i++) {
 633                 desc.range[i].len = pagebuffers[i].len;
 634                 desc.range[i].offset = pagebuffers[i].offset;
 635                 desc.range[i].pfn        = pagebuffers[i].pfn;
 636         }
 637
 638         sg_init_table(bufferlist, 3);
 639         sg_set_buf(&bufferlist[0], &desc, descsize);
 640         sg_set_buf(&bufferlist[1], buffer, bufferlen);
 641         sg_set_buf(&bufferlist[2], &aligned_data,
 642                 packetlen_aligned - packetlen);
 643
 644         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
 645
 646         if (ret == 0 && signal)
 647                 vmbus_setevent(channel);
 648
 649         return ret;
 650 }
 651 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
 652
 653 /*
 654  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
 655  * using a GPADL Direct packet type.
 656  */
 657 int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
 658                                 struct hv_multipage_buffer *multi_pagebuffer,
 659                                 void *buffer, u32 bufferlen, u64 requestid)
 660 {
 661         int ret;
 662         struct vmbus_channel_packet_multipage_buffer desc;
 663         u32 descsize;
 664         u32 packetlen;
 665         u32 packetlen_aligned;
 666         struct scatterlist bufferlist[3];
 667         u64 aligned_data = 0;
 668         bool signal = false;
 669         u32 pfncount = NUM_PAGES_SPANNED(multi_pagebuffer->offset,
 670                                          multi_pagebuffer->len);
 671
 672
 673         if ((pfncount < 0) || (pfncount > MAX_MULTIPAGE_BUFFER_COUNT))
 674                 return -EINVAL;
 675
 676         /*
 677          * Adjust the size down since vmbus_channel_packet_multipage_buffer is
 678          * the largest size we support
 679          */
 680         descsize = sizeof(struct vmbus_channel_packet_multipage_buffer) -
 681                           ((MAX_MULTIPAGE_BUFFER_COUNT - pfncount) *
 682                           sizeof(u64));
 683         packetlen = descsize + bufferlen;
 684         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 685
 686
 687         /* Setup the descriptor */
 688         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
 689         desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 690         desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
 691         desc.length8 = (u16)(packetlen_aligned >> 3);
 692         desc.transactionid = requestid;
 693         desc.rangecount = 1;
 694
 695         desc.range.len = multi_pagebuffer->len;
 696         desc.range.offset = multi_pagebuffer->offset;
 697
 698         memcpy(desc.range.pfn_array, multi_pagebuffer->pfn_array,
 699                pfncount * sizeof(u64));
 700
 701         sg_init_table(bufferlist, 3);
 702         sg_set_buf(&bufferlist[0], &desc, descsize);
 703         sg_set_buf(&bufferlist[1], buffer, bufferlen);
 704         sg_set_buf(&bufferlist[2], &aligned_data,
 705                 packetlen_aligned - packetlen);
 706
 707         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
 708
 709         if (ret == 0 && signal)
 710                 vmbus_setevent(channel);
 711
 712         return ret;
 713 }
 714 EXPORT_SYMBOL_GPL(vmbus_sendpacket_multipagebuffer);
 715
 716 /**
 717  * vmbus_recvpacket() - Retrieve the user packet on the specified channel
 718  * @channel: Pointer to vmbus_channel structure.
 719  * @buffer: Pointer to the buffer you want to receive the data into.
 720  * @bufferlen: Maximum size of what the the buffer will hold
 721  * @buffer_actual_len: The actual size of the data after it was received
 722  * @requestid: Identifier of the request
 723  *
 724  * Receives directly from the hyper-v vmbus and puts the data it received
 725  * into Buffer. This will receive the data unparsed from hyper-v.
 726  *
 727  * Mainly used by Hyper-V drivers.
 728  */
 729 int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
 730                         u32 bufferlen, u32 *buffer_actual_len, u64 *requestid)
 731 {
 732         struct vmpacket_descriptor desc;
 733         u32 packetlen;
 734         u32 userlen;
 735         int ret;
 736         bool signal = false;
 737
 738         *buffer_actual_len = 0;
 739         *requestid = 0;
 740
 741
 742         ret = hv_ringbuffer_peek(&channel->inbound, &desc,
 743                              sizeof(struct vmpacket_descriptor));
 744         if (ret != 0)
 745                 return 0;
 746
 747         packetlen = desc.len8 << 3;
 748         userlen = packetlen - (desc.offset8 << 3);
 749
 750         *buffer_actual_len = userlen;
 751
 752         if (userlen > bufferlen) {
 753
 754                 pr_err("Buffer too small - got %d needs %d\n",
 755                            bufferlen, userlen);
 756                 return -ETOOSMALL;
 757         }
 758
 759         *requestid = desc.trans_id;
 760
 761         /* Copy over the packet to the user buffer */
 762         ret = hv_ringbuffer_read(&channel->inbound, buffer, userlen,
 763                              (desc.offset8 << 3), &signal);
 764
 765         if (signal)
 766                 vmbus_setevent(channel);
 767
 768         return 0;
 769 }
 770 EXPORT_SYMBOL(vmbus_recvpacket);
 771
 772 /*
 773  * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
 774  */
 775 int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
 776                               u32 bufferlen, u32 *buffer_actual_len,
 777                               u64 *requestid)
 778 {
 779         struct vmpacket_descriptor desc;
 780         u32 packetlen;
 781         int ret;
 782         bool signal = false;
 783
 784         *buffer_actual_len = 0;
 785         *requestid = 0;
 786
 787
 788         ret = hv_ringbuffer_peek(&channel->inbound, &desc,
 789                              sizeof(struct vmpacket_descriptor));
 790         if (ret != 0)
 791                 return 0;
 792
 793
 794         packetlen = desc.len8 << 3;
 795
 796         *buffer_actual_len = packetlen;
 797
 798         if (packetlen > bufferlen) {
 799                 pr_err("Buffer too small - needed %d bytes but "
 800                         "got space for only %d bytes\n",
 801                         packetlen, bufferlen);
 802                 return -ENOBUFS;
 803         }
 804
 805         *requestid = desc.trans_id;
 806
 807         /* Copy over the entire packet to the user buffer */
 808         ret = hv_ringbuffer_read(&channel->inbound, buffer, packetlen, 0,
 809                                  &signal);
 810
 811         if (signal)
 812                 vmbus_setevent(channel);
 813
 814         return ret;
 815 }
 816 EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);