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         struct vmbus_channel_gpadl_header *gpadl_header;
 213         struct vmbus_channel_gpadl_body *gpadl_body;
 214         struct vmbus_channel_msginfo *msgheader;
 215         struct vmbus_channel_msginfo *msgbody = NULL;
 216         u32 msgsize;
 217
 218         int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
 219
 220         pagecount = size >> PAGE_SHIFT;
 221
 222         /* do we need a gpadl body msg */
 223         pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 224                   sizeof(struct vmbus_channel_gpadl_header) -
 225                   sizeof(struct gpa_range);
 226         pfncount = pfnsize / sizeof(u64);
 227
 228         if (pagecount > pfncount) {
 229                 /* we need a gpadl body */
 230                 /* fill in the header */
 231                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 232                           sizeof(struct vmbus_channel_gpadl_header) +
 233                           sizeof(struct gpa_range) + pfncount * sizeof(u64);
 234                 msgheader =  kzalloc(msgsize, GFP_KERNEL);
 235                 if (!msgheader)
 236                         goto nomem;
 237
 238                 INIT_LIST_HEAD(&msgheader->submsglist);
 239                 msgheader->msgsize = msgsize;
 240
 241                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 242                         msgheader->msg;
 243                 gpadl_header->rangecount = 1;
 244                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 245                                          pagecount * sizeof(u64);
 246                 gpadl_header->range[0].byte_offset = 0;
 247                 gpadl_header->range[0].byte_count = size;
 248                 for (i = 0; i < pfncount; i++)
 249                         gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
 250                                 kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 251                 *msginfo = msgheader;
 252                 *messagecount = 1;
 253
 254                 pfnsum = pfncount;
 255                 pfnleft = pagecount - pfncount;
 256
 257                 /* how many pfns can we fit */
 258                 pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 259                           sizeof(struct vmbus_channel_gpadl_body);
 260                 pfncount = pfnsize / sizeof(u64);
 261
 262                 /* fill in the body */
 263                 while (pfnleft) {
 264                         if (pfnleft > pfncount)
 265                                 pfncurr = pfncount;
 266                         else
 267                                 pfncurr = pfnleft;
 268
 269                         msgsize = sizeof(struct vmbus_channel_msginfo) +
 270                                   sizeof(struct vmbus_channel_gpadl_body) +
 271                                   pfncurr * sizeof(u64);
 272                         msgbody = kzalloc(msgsize, GFP_KERNEL);
 273
 274                         if (!msgbody) {
 275                                 struct vmbus_channel_msginfo *pos = NULL;
 276                                 struct vmbus_channel_msginfo *tmp = NULL;
 277                                 /*
 278                                  * Free up all the allocated messages.
 279                                  */
 280                                 list_for_each_entry_safe(pos, tmp,
 281                                         &msgheader->submsglist,
 282                                         msglistentry) {
 283
 284                                         list_del(&pos->msglistentry);
 285                                         kfree(pos);
 286                                 }
 287
 288                                 goto nomem;
 289                         }
 290
 291                         msgbody->msgsize = msgsize;
 292                         (*messagecount)++;
 293                         gpadl_body =
 294                                 (struct vmbus_channel_gpadl_body *)msgbody->msg;
 295
 296                         /*
 297                          * Gpadl is u32 and we are using a pointer which could
 298                          * be 64-bit
 299                          * This is governed by the guest/host protocol and
 300                          * so the hypervisor gurantees that this is ok.
 301                          */
 302                         for (i = 0; i < pfncurr; i++)
 303                                 gpadl_body->pfn[i] = slow_virt_to_phys(
 304                                         kbuffer + PAGE_SIZE * (pfnsum + i)) >>
 305                                         PAGE_SHIFT;
 306
 307                         /* add to msg header */
 308                         list_add_tail(&msgbody->msglistentry,
 309                                       &msgheader->submsglist);
 310                         pfnsum += pfncurr;
 311                         pfnleft -= pfncurr;
 312                 }
 313         } else {
 314                 /* everything fits in a header */
 315                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 316                           sizeof(struct vmbus_channel_gpadl_header) +
 317                           sizeof(struct gpa_range) + pagecount * sizeof(u64);
 318                 msgheader = kzalloc(msgsize, GFP_KERNEL);
 319                 if (msgheader == NULL)
 320                         goto nomem;
 321                 msgheader->msgsize = msgsize;
 322
 323                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 324                         msgheader->msg;
 325                 gpadl_header->rangecount = 1;
 326                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 327                                          pagecount * sizeof(u64);
 328                 gpadl_header->range[0].byte_offset = 0;
 329                 gpadl_header->range[0].byte_count = size;
 330                 for (i = 0; i < pagecount; i++)
 331                         gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
 332                                 kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 333
 334                 *msginfo = msgheader;
 335                 *messagecount = 1;
 336         }
 337
 338         return 0;
 339 nomem:
 340         kfree(msgheader);
 341         kfree(msgbody);
 342         return -ENOMEM;
 343 }
 344
 345 /*
 346  * vmbus_establish_gpadl - Estabish a GPADL for the specified buffer
 347  *
 348  * @channel: a channel
 349  * @kbuffer: from kmalloc or vmalloc
 350  * @size: page-size multiple
 351  * @gpadl_handle: some funky thing
 352  */
 353 int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
 354                                u32 size, u32 *gpadl_handle)
 355 {
 356         struct vmbus_channel_gpadl_header *gpadlmsg;
 357         struct vmbus_channel_gpadl_body *gpadl_body;
 358         struct vmbus_channel_msginfo *msginfo = NULL;
 359         struct vmbus_channel_msginfo *submsginfo;
 360         u32 msgcount;
 361         struct list_head *curr;
 362         u32 next_gpadl_handle;
 363         unsigned long flags;
 364         int ret = 0;
 365         int t;
 366
 367         next_gpadl_handle = atomic_read(&vmbus_connection.next_gpadl_handle);
 368         atomic_inc(&vmbus_connection.next_gpadl_handle);
 369
 370         ret = create_gpadl_header(kbuffer, size, &msginfo, &msgcount);
 371         if (ret)
 372                 return ret;
 373
 374         init_completion(&msginfo->waitevent);
 375
 376         gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
 377         gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
 378         gpadlmsg->child_relid = channel->offermsg.child_relid;
 379         gpadlmsg->gpadl = next_gpadl_handle;
 380
 381
 382         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 383         list_add_tail(&msginfo->msglistentry,
 384                       &vmbus_connection.chn_msg_list);
 385
 386         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 387
 388         ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize -
 389                                sizeof(*msginfo));
 390         if (ret != 0)
 391                 goto cleanup;
 392
 393         if (msgcount > 1) {
 394                 list_for_each(curr, &msginfo->submsglist) {
 395
 396                         submsginfo = (struct vmbus_channel_msginfo *)curr;
 397                         gpadl_body =
 398                              (struct vmbus_channel_gpadl_body *)submsginfo->msg;
 399
 400                         gpadl_body->header.msgtype =
 401                                 CHANNELMSG_GPADL_BODY;
 402                         gpadl_body->gpadl = next_gpadl_handle;
 403
 404                         ret = vmbus_post_msg(gpadl_body,
 405                                                submsginfo->msgsize -
 406                                                sizeof(*submsginfo));
 407                         if (ret != 0)
 408                                 goto cleanup;
 409
 410                 }
 411         }
 412         t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
 413         BUG_ON(t == 0);
 414
 415
 416         /* At this point, we received the gpadl created msg */
 417         *gpadl_handle = gpadlmsg->gpadl;
 418
 419 cleanup:
 420         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 421         list_del(&msginfo->msglistentry);
 422         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 423
 424         kfree(msginfo);
 425         return ret;
 426 }
 427 EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
 428
 429 /*
 430  * vmbus_teardown_gpadl -Teardown the specified GPADL handle
 431  */
 432 int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
 433 {
 434         struct vmbus_channel_gpadl_teardown *msg;
 435         struct vmbus_channel_msginfo *info;
 436         unsigned long flags;
 437         int ret, t;
 438
 439         info = kmalloc(sizeof(*info) +
 440                        sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
 441         if (!info)
 442                 return -ENOMEM;
 443
 444         init_completion(&info->waitevent);
 445
 446         msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
 447
 448         msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
 449         msg->child_relid = channel->offermsg.child_relid;
 450         msg->gpadl = gpadl_handle;
 451
 452         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 453         list_add_tail(&info->msglistentry,
 454                       &vmbus_connection.chn_msg_list);
 455         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 456         ret = vmbus_post_msg(msg,
 457                                sizeof(struct vmbus_channel_gpadl_teardown));
 458
 459         BUG_ON(ret != 0);
 460         t = wait_for_completion_timeout(&info->waitevent, 5*HZ);
 461         BUG_ON(t == 0);
 462
 463         /* Received a torndown response */
 464         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 465         list_del(&info->msglistentry);
 466         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 467
 468         kfree(info);
 469         return ret;
 470 }
 471 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
 472
 473 static void vmbus_close_internal(struct vmbus_channel *channel)
 474 {
 475         struct vmbus_channel_close_channel *msg;
 476         int ret;
 477         unsigned long flags;
 478
 479         channel->state = CHANNEL_OPEN_STATE;
 480         channel->sc_creation_callback = NULL;
 481         /* Stop callback and cancel the timer asap */
 482         spin_lock_irqsave(&channel->inbound_lock, flags);
 483         channel->onchannel_callback = NULL;
 484         spin_unlock_irqrestore(&channel->inbound_lock, flags);
 485
 486         /* Send a closing message */
 487
 488         msg = &channel->close_msg.msg;
 489
 490         msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
 491         msg->child_relid = channel->offermsg.child_relid;
 492
 493         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel));
 494
 495         BUG_ON(ret != 0);
 496         /* Tear down the gpadl for the channel's ring buffer */
 497         if (channel->ringbuffer_gpadlhandle)
 498                 vmbus_teardown_gpadl(channel,
 499                                           channel->ringbuffer_gpadlhandle);
 500
 501         /* Cleanup the ring buffers for this channel */
 502         hv_ringbuffer_cleanup(&channel->outbound);
 503         hv_ringbuffer_cleanup(&channel->inbound);
 504
 505         free_pages((unsigned long)channel->ringbuffer_pages,
 506                 get_order(channel->ringbuffer_pagecount * PAGE_SIZE));
 507
 508
 509 }
 510
 511 /*
 512  * vmbus_close - Close the specified channel
 513  */
 514 void vmbus_close(struct vmbus_channel *channel)
 515 {
 516         struct list_head *cur, *tmp;
 517         struct vmbus_channel *cur_channel;
 518
 519         if (channel->primary_channel != NULL) {
 520                 /*
 521                  * We will only close sub-channels when
 522                  * the primary is closed.
 523                  */
 524                 return;
 525         }
 526         /*
 527          * Close all the sub-channels first and then close the
 528          * primary channel.
 529          */
 530         list_for_each_safe(cur, tmp, &channel->sc_list) {
 531                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 532                 if (cur_channel->state != CHANNEL_OPENED_STATE)
 533                         continue;
 534                 vmbus_close_internal(cur_channel);
 535         }
 536         /*
 537          * Now close the primary.
 538          */
 539         vmbus_close_internal(channel);
 540 }
 541 EXPORT_SYMBOL_GPL(vmbus_close);
 542
 543 /**
 544  * vmbus_sendpacket() - Send the specified buffer on the given channel
 545  * @channel: Pointer to vmbus_channel structure.
 546  * @buffer: Pointer to the buffer you want to receive the data into.
 547  * @bufferlen: Maximum size of what the the buffer will hold
 548  * @requestid: Identifier of the request
 549  * @type: Type of packet that is being send e.g. negotiate, time
 550  * packet etc.
 551  *
 552  * Sends data in @buffer directly to hyper-v via the vmbus
 553  * This will send the data unparsed to hyper-v.
 554  *
 555  * Mainly used by Hyper-V drivers.
 556  */
 557 int vmbus_sendpacket(struct vmbus_channel *channel, const void *buffer,
 558                            u32 bufferlen, u64 requestid,
 559                            enum vmbus_packet_type type, u32 flags)
 560 {
 561         struct vmpacket_descriptor desc;
 562         u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
 563         u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 564         struct scatterlist bufferlist[3];
 565         u64 aligned_data = 0;
 566         int ret;
 567         bool signal = false;
 568
 569
 570         /* Setup the descriptor */
 571         desc.type = type; /* VmbusPacketTypeDataInBand; */
 572         desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
 573         /* in 8-bytes granularity */
 574         desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3;
 575         desc.len8 = (u16)(packetlen_aligned >> 3);
 576         desc.trans_id = requestid;
 577
 578         sg_init_table(bufferlist, 3);
 579         sg_set_buf(&bufferlist[0], &desc, sizeof(struct vmpacket_descriptor));
 580         sg_set_buf(&bufferlist[1], buffer, bufferlen);
 581         sg_set_buf(&bufferlist[2], &aligned_data,
 582                    packetlen_aligned - packetlen);
 583
 584         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
 585
 586         if (ret == 0 && signal)
 587                 vmbus_setevent(channel);
 588
 589         return ret;
 590 }
 591 EXPORT_SYMBOL(vmbus_sendpacket);
 592
 593 /*
 594  * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
 595  * packets using a GPADL Direct packet type.
 596  */
 597 int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
 598                                      struct hv_page_buffer pagebuffers[],
 599                                      u32 pagecount, void *buffer, u32 bufferlen,
 600                                      u64 requestid)
 601 {
 602         int ret;
 603         int i;
 604         struct vmbus_channel_packet_page_buffer desc;
 605         u32 descsize;
 606         u32 packetlen;
 607         u32 packetlen_aligned;
 608         struct scatterlist bufferlist[3];
 609         u64 aligned_data = 0;
 610         bool signal = false;
 611
 612         if (pagecount > MAX_PAGE_BUFFER_COUNT)
 613                 return -EINVAL;
 614
 615
 616         /*
 617          * Adjust the size down since vmbus_channel_packet_page_buffer is the
 618          * largest size we support
 619          */
 620         descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
 621                           ((MAX_PAGE_BUFFER_COUNT - pagecount) *
 622                           sizeof(struct hv_page_buffer));
 623         packetlen = descsize + bufferlen;
 624         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 625
 626         /* Setup the descriptor */
 627         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
 628         desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 629         desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
 630         desc.length8 = (u16)(packetlen_aligned >> 3);
 631         desc.transactionid = requestid;
 632         desc.rangecount = pagecount;
 633
 634         for (i = 0; i < pagecount; i++) {
 635                 desc.range[i].len = pagebuffers[i].len;
 636                 desc.range[i].offset = pagebuffers[i].offset;
 637                 desc.range[i].pfn        = pagebuffers[i].pfn;
 638         }
 639
 640         sg_init_table(bufferlist, 3);
 641         sg_set_buf(&bufferlist[0], &desc, descsize);
 642         sg_set_buf(&bufferlist[1], buffer, bufferlen);
 643         sg_set_buf(&bufferlist[2], &aligned_data,
 644                 packetlen_aligned - packetlen);
 645
 646         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
 647
 648         if (ret == 0 && signal)
 649                 vmbus_setevent(channel);
 650
 651         return ret;
 652 }
 653 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
 654
 655 /*
 656  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
 657  * using a GPADL Direct packet type.
 658  */
 659 int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
 660                                 struct hv_multipage_buffer *multi_pagebuffer,
 661                                 void *buffer, u32 bufferlen, u64 requestid)
 662 {
 663         int ret;
 664         struct vmbus_channel_packet_multipage_buffer desc;
 665         u32 descsize;
 666         u32 packetlen;
 667         u32 packetlen_aligned;
 668         struct scatterlist bufferlist[3];
 669         u64 aligned_data = 0;
 670         bool signal = false;
 671         u32 pfncount = NUM_PAGES_SPANNED(multi_pagebuffer->offset,
 672                                          multi_pagebuffer->len);
 673
 674
 675         if ((pfncount < 0) || (pfncount > MAX_MULTIPAGE_BUFFER_COUNT))
 676                 return -EINVAL;
 677
 678         /*
 679          * Adjust the size down since vmbus_channel_packet_multipage_buffer is
 680          * the largest size we support
 681          */
 682         descsize = sizeof(struct vmbus_channel_packet_multipage_buffer) -
 683                           ((MAX_MULTIPAGE_BUFFER_COUNT - pfncount) *
 684                           sizeof(u64));
 685         packetlen = descsize + bufferlen;
 686         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 687
 688
 689         /* Setup the descriptor */
 690         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
 691         desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 692         desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
 693         desc.length8 = (u16)(packetlen_aligned >> 3);
 694         desc.transactionid = requestid;
 695         desc.rangecount = 1;
 696
 697         desc.range.len = multi_pagebuffer->len;
 698         desc.range.offset = multi_pagebuffer->offset;
 699
 700         memcpy(desc.range.pfn_array, multi_pagebuffer->pfn_array,
 701                pfncount * sizeof(u64));
 702
 703         sg_init_table(bufferlist, 3);
 704         sg_set_buf(&bufferlist[0], &desc, descsize);
 705         sg_set_buf(&bufferlist[1], buffer, bufferlen);
 706         sg_set_buf(&bufferlist[2], &aligned_data,
 707                 packetlen_aligned - packetlen);
 708
 709         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
 710
 711         if (ret == 0 && signal)
 712                 vmbus_setevent(channel);
 713
 714         return ret;
 715 }
 716 EXPORT_SYMBOL_GPL(vmbus_sendpacket_multipagebuffer);
 717
 718 /**
 719  * vmbus_recvpacket() - Retrieve the user packet on the specified channel
 720  * @channel: Pointer to vmbus_channel structure.
 721  * @buffer: Pointer to the buffer you want to receive the data into.
 722  * @bufferlen: Maximum size of what the the buffer will hold
 723  * @buffer_actual_len: The actual size of the data after it was received
 724  * @requestid: Identifier of the request
 725  *
 726  * Receives directly from the hyper-v vmbus and puts the data it received
 727  * into Buffer. This will receive the data unparsed from hyper-v.
 728  *
 729  * Mainly used by Hyper-V drivers.
 730  */
 731 int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
 732                         u32 bufferlen, u32 *buffer_actual_len, u64 *requestid)
 733 {
 734         struct vmpacket_descriptor desc;
 735         u32 packetlen;
 736         u32 userlen;
 737         int ret;
 738         bool signal = false;
 739
 740         *buffer_actual_len = 0;
 741         *requestid = 0;
 742
 743
 744         ret = hv_ringbuffer_peek(&channel->inbound, &desc,
 745                              sizeof(struct vmpacket_descriptor));
 746         if (ret != 0)
 747                 return 0;
 748
 749         packetlen = desc.len8 << 3;
 750         userlen = packetlen - (desc.offset8 << 3);
 751
 752         *buffer_actual_len = userlen;
 753
 754         if (userlen > bufferlen) {
 755
 756                 pr_err("Buffer too small - got %d needs %d\n",
 757                            bufferlen, userlen);
 758                 return -ETOOSMALL;
 759         }
 760
 761         *requestid = desc.trans_id;
 762
 763         /* Copy over the packet to the user buffer */
 764         ret = hv_ringbuffer_read(&channel->inbound, buffer, userlen,
 765                              (desc.offset8 << 3), &signal);
 766
 767         if (signal)
 768                 vmbus_setevent(channel);
 769
 770         return 0;
 771 }
 772 EXPORT_SYMBOL(vmbus_recvpacket);
 773
 774 /*
 775  * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
 776  */
 777 int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
 778                               u32 bufferlen, u32 *buffer_actual_len,
 779                               u64 *requestid)
 780 {
 781         struct vmpacket_descriptor desc;
 782         u32 packetlen;
 783         int ret;
 784         bool signal = false;
 785
 786         *buffer_actual_len = 0;
 787         *requestid = 0;
 788
 789
 790         ret = hv_ringbuffer_peek(&channel->inbound, &desc,
 791                              sizeof(struct vmpacket_descriptor));
 792         if (ret != 0)
 793                 return 0;
 794
 795
 796         packetlen = desc.len8 << 3;
 797
 798         *buffer_actual_len = packetlen;
 799
 800         if (packetlen > bufferlen) {
 801                 pr_err("Buffer too small - needed %d bytes but "
 802                         "got space for only %d bytes\n",
 803                         packetlen, bufferlen);
 804                 return -ENOBUFS;
 805         }
 806
 807         *requestid = desc.trans_id;
 808
 809         /* Copy over the entire packet to the user buffer */
 810         ret = hv_ringbuffer_read(&channel->inbound, buffer, packetlen, 0,
 811                                  &signal);
 812
 813         if (signal)
 814                 vmbus_setevent(channel);
 815
 816         return ret;
 817 }
 818 EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);