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
  32 #include "hyperv_vmbus.h"
  33
  34 #define NUM_PAGES_SPANNED(addr, len) \
  35 ((PAGE_ALIGN(addr + len) >> PAGE_SHIFT) - (addr >> PAGE_SHIFT))
  36
  37 /*
  38  * vmbus_setevent- Trigger an event notification on the specified
  39  * channel.
  40  */
  41 static void vmbus_setevent(struct vmbus_channel *channel)
  42 {
  43         struct hv_monitor_page *monitorpage;
  44
  45         if (channel->offermsg.monitor_allocated) {
  46                 /* Each u32 represents 32 channels */
  47                 sync_set_bit(channel->offermsg.child_relid & 31,
  48                         (unsigned long *) vmbus_connection.send_int_page +
  49                         (channel->offermsg.child_relid >> 5));
  50
  51                 /* Get the child to parent monitor page */
  52                 monitorpage = vmbus_connection.monitor_pages[1];
  53
  54                 sync_set_bit(channel->monitor_bit,
  55                         (unsigned long *)&monitorpage->trigger_group
  56                                         [channel->monitor_grp].pending);
  57
  58         } else {
  59                 vmbus_set_event(channel);
  60         }
  61 }
  62
  63 /*
  64  * vmbus_open - Open the specified channel.
  65  */
  66 int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
  67                      u32 recv_ringbuffer_size, void *userdata, u32 userdatalen,
  68                      void (*onchannelcallback)(void *context), void *context)
  69 {
  70         struct vmbus_channel_open_channel *open_msg;
  71         struct vmbus_channel_msginfo *open_info = NULL;
  72         void *in, *out;
  73         unsigned long flags;
  74         int ret, t, err = 0;
  75
  76         spin_lock_irqsave(&newchannel->sc_lock, flags);
  77         if (newchannel->state == CHANNEL_OPEN_STATE) {
  78                 newchannel->state = CHANNEL_OPENING_STATE;
  79         } else {
  80                 spin_unlock_irqrestore(&newchannel->sc_lock, flags);
  81                 return -EINVAL;
  82         }
  83         spin_unlock_irqrestore(&newchannel->sc_lock, flags);
  84
  85         newchannel->onchannel_callback = onchannelcallback;
  86         newchannel->channel_callback_context = context;
  87
  88         /* Allocate the ring buffer */
  89         out = (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
  90                 get_order(send_ringbuffer_size + recv_ringbuffer_size));
  91
  92         if (!out)
  93                 return -ENOMEM;
  94
  95
  96         in = (void *)((unsigned long)out + send_ringbuffer_size);
  97
  98         newchannel->ringbuffer_pages = out;
  99         newchannel->ringbuffer_pagecount = (send_ringbuffer_size +
 100                                            recv_ringbuffer_size) >> PAGE_SHIFT;
 101
 102         ret = hv_ringbuffer_init(
 103                 &newchannel->outbound, out, send_ringbuffer_size);
 104
 105         if (ret != 0) {
 106                 err = ret;
 107                 goto error0;
 108         }
 109
 110         ret = hv_ringbuffer_init(
 111                 &newchannel->inbound, in, recv_ringbuffer_size);
 112         if (ret != 0) {
 113                 err = ret;
 114                 goto error0;
 115         }
 116
 117
 118         /* Establish the gpadl for the ring buffer */
 119         newchannel->ringbuffer_gpadlhandle = 0;
 120
 121         ret = vmbus_establish_gpadl(newchannel,
 122                                          newchannel->outbound.ring_buffer,
 123                                          send_ringbuffer_size +
 124                                          recv_ringbuffer_size,
 125                                          &newchannel->ringbuffer_gpadlhandle);
 126
 127         if (ret != 0) {
 128                 err = ret;
 129                 goto error0;
 130         }
 131
 132         /* Create and init the channel open message */
 133         open_info = kmalloc(sizeof(*open_info) +
 134                            sizeof(struct vmbus_channel_open_channel),
 135                            GFP_KERNEL);
 136         if (!open_info) {
 137                 err = -ENOMEM;
 138                 goto error0;
 139         }
 140
 141         init_completion(&open_info->waitevent);
 142
 143         open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
 144         open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
 145         open_msg->openid = newchannel->offermsg.child_relid;
 146         open_msg->child_relid = newchannel->offermsg.child_relid;
 147         open_msg->ringbuffer_gpadlhandle = newchannel->ringbuffer_gpadlhandle;
 148         open_msg->downstream_ringbuffer_pageoffset = send_ringbuffer_size >>
 149                                                   PAGE_SHIFT;
 150         open_msg->target_vp = newchannel->target_vp;
 151
 152         if (userdatalen > MAX_USER_DEFINED_BYTES) {
 153                 err = -EINVAL;
 154                 goto error0;
 155         }
 156
 157         if (userdatalen)
 158                 memcpy(open_msg->userdata, userdata, userdatalen);
 159
 160         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 161         list_add_tail(&open_info->msglistentry,
 162                       &vmbus_connection.chn_msg_list);
 163         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 164
 165         ret = vmbus_post_msg(open_msg,
 166                                sizeof(struct vmbus_channel_open_channel));
 167
 168         if (ret != 0)
 169                 goto error1;
 170
 171         t = wait_for_completion_timeout(&open_info->waitevent, 5*HZ);
 172         if (t == 0) {
 173                 err = -ETIMEDOUT;
 174                 goto error1;
 175         }
 176
 177
 178         if (open_info->response.open_result.status)
 179                 err = open_info->response.open_result.status;
 180
 181         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 182         list_del(&open_info->msglistentry);
 183         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 184
 185         if (err == 0)
 186                 newchannel->state = CHANNEL_OPENED_STATE;
 187
 188         kfree(open_info);
 189         return err;
 190
 191 error1:
 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 error0:
 197         free_pages((unsigned long)out,
 198                 get_order(send_ringbuffer_size + recv_ringbuffer_size));
 199         kfree(open_info);
 200         return err;
 201 }
 202 EXPORT_SYMBOL_GPL(vmbus_open);
 203
 204 /*
 205  * create_gpadl_header - Creates a gpadl for the specified buffer
 206  */
 207 static int create_gpadl_header(void *kbuffer, u32 size,
 208                                          struct vmbus_channel_msginfo **msginfo,
 209                                          u32 *messagecount)
 210 {
 211         int i;
 212         int pagecount;
 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
 223         /* do we need a gpadl body msg */
 224         pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 225                   sizeof(struct vmbus_channel_gpadl_header) -
 226                   sizeof(struct gpa_range);
 227         pfncount = pfnsize / sizeof(u64);
 228
 229         if (pagecount > pfncount) {
 230                 /* we need a gpadl body */
 231                 /* fill in the header */
 232                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 233                           sizeof(struct vmbus_channel_gpadl_header) +
 234                           sizeof(struct gpa_range) + pfncount * sizeof(u64);
 235                 msgheader =  kzalloc(msgsize, GFP_KERNEL);
 236                 if (!msgheader)
 237                         goto nomem;
 238
 239                 INIT_LIST_HEAD(&msgheader->submsglist);
 240                 msgheader->msgsize = msgsize;
 241
 242                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 243                         msgheader->msg;
 244                 gpadl_header->rangecount = 1;
 245                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 246                                          pagecount * sizeof(u64);
 247                 gpadl_header->range[0].byte_offset = 0;
 248                 gpadl_header->range[0].byte_count = size;
 249                 for (i = 0; i < pfncount; i++)
 250                         gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
 251                                 kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 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] = slow_virt_to_phys(
 305                                         kbuffer + PAGE_SIZE * (pfnsum + i)) >>
 306                                         PAGE_SHIFT;
 307
 308                         /* add to msg header */
 309                         list_add_tail(&msgbody->msglistentry,
 310                                       &msgheader->submsglist);
 311                         pfnsum += pfncurr;
 312                         pfnleft -= pfncurr;
 313                 }
 314         } else {
 315                 /* everything fits in a header */
 316                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 317                           sizeof(struct vmbus_channel_gpadl_header) +
 318                           sizeof(struct gpa_range) + pagecount * sizeof(u64);
 319                 msgheader = kzalloc(msgsize, GFP_KERNEL);
 320                 if (msgheader == NULL)
 321                         goto nomem;
 322                 msgheader->msgsize = msgsize;
 323
 324                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 325                         msgheader->msg;
 326                 gpadl_header->rangecount = 1;
 327                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 328                                          pagecount * sizeof(u64);
 329                 gpadl_header->range[0].byte_offset = 0;
 330                 gpadl_header->range[0].byte_count = size;
 331                 for (i = 0; i < pagecount; i++)
 332                         gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
 333                                 kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 334
 335                 *msginfo = msgheader;
 336                 *messagecount = 1;
 337         }
 338
 339         return 0;
 340 nomem:
 341         kfree(msgheader);
 342         kfree(msgbody);
 343         return -ENOMEM;
 344 }
 345
 346 /*
 347  * vmbus_establish_gpadl - Estabish a GPADL for the specified buffer
 348  *
 349  * @channel: a channel
 350  * @kbuffer: from kmalloc or vmalloc
 351  * @size: page-size multiple
 352  * @gpadl_handle: some funky thing
 353  */
 354 int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
 355                                u32 size, u32 *gpadl_handle)
 356 {
 357         struct vmbus_channel_gpadl_header *gpadlmsg;
 358         struct vmbus_channel_gpadl_body *gpadl_body;
 359         struct vmbus_channel_msginfo *msginfo = NULL;
 360         struct vmbus_channel_msginfo *submsginfo;
 361         u32 msgcount;
 362         struct list_head *curr;
 363         u32 next_gpadl_handle;
 364         unsigned long flags;
 365         int ret = 0;
 366         int t;
 367
 368         next_gpadl_handle = atomic_read(&vmbus_connection.next_gpadl_handle);
 369         atomic_inc(&vmbus_connection.next_gpadl_handle);
 370
 371         ret = create_gpadl_header(kbuffer, size, &msginfo, &msgcount);
 372         if (ret)
 373                 return ret;
 374
 375         init_completion(&msginfo->waitevent);
 376
 377         gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
 378         gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
 379         gpadlmsg->child_relid = channel->offermsg.child_relid;
 380         gpadlmsg->gpadl = next_gpadl_handle;
 381
 382
 383         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 384         list_add_tail(&msginfo->msglistentry,
 385                       &vmbus_connection.chn_msg_list);
 386
 387         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 388
 389         ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize -
 390                                sizeof(*msginfo));
 391         if (ret != 0)
 392                 goto cleanup;
 393
 394         if (msgcount > 1) {
 395                 list_for_each(curr, &msginfo->submsglist) {
 396
 397                         submsginfo = (struct vmbus_channel_msginfo *)curr;
 398                         gpadl_body =
 399                              (struct vmbus_channel_gpadl_body *)submsginfo->msg;
 400
 401                         gpadl_body->header.msgtype =
 402                                 CHANNELMSG_GPADL_BODY;
 403                         gpadl_body->gpadl = next_gpadl_handle;
 404
 405                         ret = vmbus_post_msg(gpadl_body,
 406                                                submsginfo->msgsize -
 407                                                sizeof(*submsginfo));
 408                         if (ret != 0)
 409                                 goto cleanup;
 410
 411                 }
 412         }
 413         t = wait_for_completion_timeout(&msginfo->waitevent, 5*HZ);
 414         BUG_ON(t == 0);
 415
 416
 417         /* At this point, we received the gpadl created msg */
 418         *gpadl_handle = gpadlmsg->gpadl;
 419
 420 cleanup:
 421         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 422         list_del(&msginfo->msglistentry);
 423         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 424
 425         kfree(msginfo);
 426         return ret;
 427 }
 428 EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
 429
 430 /*
 431  * vmbus_teardown_gpadl -Teardown the specified GPADL handle
 432  */
 433 int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
 434 {
 435         struct vmbus_channel_gpadl_teardown *msg;
 436         struct vmbus_channel_msginfo *info;
 437         unsigned long flags;
 438         int ret, t;
 439
 440         info = kmalloc(sizeof(*info) +
 441                        sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
 442         if (!info)
 443                 return -ENOMEM;
 444
 445         init_completion(&info->waitevent);
 446
 447         msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
 448
 449         msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
 450         msg->child_relid = channel->offermsg.child_relid;
 451         msg->gpadl = gpadl_handle;
 452
 453         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 454         list_add_tail(&info->msglistentry,
 455                       &vmbus_connection.chn_msg_list);
 456         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 457         ret = vmbus_post_msg(msg,
 458                                sizeof(struct vmbus_channel_gpadl_teardown));
 459
 460         BUG_ON(ret != 0);
 461         t = wait_for_completion_timeout(&info->waitevent, 5*HZ);
 462         BUG_ON(t == 0);
 463
 464         /* Received a torndown response */
 465         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 466         list_del(&info->msglistentry);
 467         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 468
 469         kfree(info);
 470         return ret;
 471 }
 472 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
 473
 474 static void reset_channel_cb(void *arg)
 475 {
 476         struct vmbus_channel *channel = arg;
 477
 478         channel->onchannel_callback = NULL;
 479 }
 480
 481 static void vmbus_close_internal(struct vmbus_channel *channel)
 482 {
 483         struct vmbus_channel_close_channel *msg;
 484         int ret;
 485
 486         channel->state = CHANNEL_OPEN_STATE;
 487         channel->sc_creation_callback = NULL;
 488         /* Stop callback and cancel the timer asap */
 489         if (channel->target_cpu != smp_processor_id())
 490                 smp_call_function_single(channel->target_cpu, reset_channel_cb,
 491                                          channel, true);
 492         else
 493                 reset_channel_cb(channel);
 494
 495         /* Send a closing message */
 496
 497         msg = &channel->close_msg.msg;
 498
 499         msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
 500         msg->child_relid = channel->offermsg.child_relid;
 501
 502         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel));
 503
 504         BUG_ON(ret != 0);
 505         /* Tear down the gpadl for the channel's ring buffer */
 506         if (channel->ringbuffer_gpadlhandle)
 507                 vmbus_teardown_gpadl(channel,
 508                                           channel->ringbuffer_gpadlhandle);
 509
 510         /* Cleanup the ring buffers for this channel */
 511         hv_ringbuffer_cleanup(&channel->outbound);
 512         hv_ringbuffer_cleanup(&channel->inbound);
 513
 514         free_pages((unsigned long)channel->ringbuffer_pages,
 515                 get_order(channel->ringbuffer_pagecount * PAGE_SIZE));
 516
 517
 518 }
 519
 520 /*
 521  * vmbus_close - Close the specified channel
 522  */
 523 void vmbus_close(struct vmbus_channel *channel)
 524 {
 525         struct list_head *cur, *tmp;
 526         struct vmbus_channel *cur_channel;
 527
 528         if (channel->primary_channel != NULL) {
 529                 /*
 530                  * We will only close sub-channels when
 531                  * the primary is closed.
 532                  */
 533                 return;
 534         }
 535         /*
 536          * Close all the sub-channels first and then close the
 537          * primary channel.
 538          */
 539         list_for_each_safe(cur, tmp, &channel->sc_list) {
 540                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 541                 if (cur_channel->state != CHANNEL_OPENED_STATE)
 542                         continue;
 543                 vmbus_close_internal(cur_channel);
 544         }
 545         /*
 546          * Now close the primary.
 547          */
 548         vmbus_close_internal(channel);
 549 }
 550 EXPORT_SYMBOL_GPL(vmbus_close);
 551
 552 /**
 553  * vmbus_sendpacket() - Send the specified buffer on the given channel
 554  * @channel: Pointer to vmbus_channel structure.
 555  * @buffer: Pointer to the buffer you want to receive the data into.
 556  * @bufferlen: Maximum size of what the the buffer will hold
 557  * @requestid: Identifier of the request
 558  * @type: Type of packet that is being send e.g. negotiate, time
 559  * packet etc.
 560  *
 561  * Sends data in @buffer directly to hyper-v via the vmbus
 562  * This will send the data unparsed to hyper-v.
 563  *
 564  * Mainly used by Hyper-V drivers.
 565  */
 566 int vmbus_sendpacket(struct vmbus_channel *channel, void *buffer,
 567                            u32 bufferlen, u64 requestid,
 568                            enum vmbus_packet_type type, u32 flags)
 569 {
 570         struct vmpacket_descriptor desc;
 571         u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
 572         u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 573         struct kvec bufferlist[3];
 574         u64 aligned_data = 0;
 575         int ret;
 576         bool signal = false;
 577
 578
 579         /* Setup the descriptor */
 580         desc.type = type; /* VmbusPacketTypeDataInBand; */
 581         desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
 582         /* in 8-bytes granularity */
 583         desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3;
 584         desc.len8 = (u16)(packetlen_aligned >> 3);
 585         desc.trans_id = requestid;
 586
 587         bufferlist[0].iov_base = &desc;
 588         bufferlist[0].iov_len = sizeof(struct vmpacket_descriptor);
 589         bufferlist[1].iov_base = buffer;
 590         bufferlist[1].iov_len = bufferlen;
 591         bufferlist[2].iov_base = &aligned_data;
 592         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 593
 594         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
 595
 596         if (ret == 0 && signal)
 597                 vmbus_setevent(channel);
 598
 599         return ret;
 600 }
 601 EXPORT_SYMBOL(vmbus_sendpacket);
 602
 603 /*
 604  * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
 605  * packets using a GPADL Direct packet type.
 606  */
 607 int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
 608                                      struct hv_page_buffer pagebuffers[],
 609                                      u32 pagecount, void *buffer, u32 bufferlen,
 610                                      u64 requestid)
 611 {
 612         int ret;
 613         int i;
 614         struct vmbus_channel_packet_page_buffer desc;
 615         u32 descsize;
 616         u32 packetlen;
 617         u32 packetlen_aligned;
 618         struct kvec bufferlist[3];
 619         u64 aligned_data = 0;
 620         bool signal = false;
 621
 622         if (pagecount > MAX_PAGE_BUFFER_COUNT)
 623                 return -EINVAL;
 624
 625
 626         /*
 627          * Adjust the size down since vmbus_channel_packet_page_buffer is the
 628          * largest size we support
 629          */
 630         descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
 631                           ((MAX_PAGE_BUFFER_COUNT - pagecount) *
 632                           sizeof(struct hv_page_buffer));
 633         packetlen = descsize + bufferlen;
 634         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 635
 636         /* Setup the descriptor */
 637         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
 638         desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 639         desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
 640         desc.length8 = (u16)(packetlen_aligned >> 3);
 641         desc.transactionid = requestid;
 642         desc.rangecount = pagecount;
 643
 644         for (i = 0; i < pagecount; i++) {
 645                 desc.range[i].len = pagebuffers[i].len;
 646                 desc.range[i].offset = pagebuffers[i].offset;
 647                 desc.range[i].pfn        = pagebuffers[i].pfn;
 648         }
 649
 650         bufferlist[0].iov_base = &desc;
 651         bufferlist[0].iov_len = descsize;
 652         bufferlist[1].iov_base = buffer;
 653         bufferlist[1].iov_len = bufferlen;
 654         bufferlist[2].iov_base = &aligned_data;
 655         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 656
 657         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
 658
 659         if (ret == 0 && signal)
 660                 vmbus_setevent(channel);
 661
 662         return ret;
 663 }
 664 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
 665
 666 /*
 667  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
 668  * using a GPADL Direct packet type.
 669  */
 670 int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
 671                                 struct hv_multipage_buffer *multi_pagebuffer,
 672                                 void *buffer, u32 bufferlen, u64 requestid)
 673 {
 674         int ret;
 675         struct vmbus_channel_packet_multipage_buffer desc;
 676         u32 descsize;
 677         u32 packetlen;
 678         u32 packetlen_aligned;
 679         struct kvec bufferlist[3];
 680         u64 aligned_data = 0;
 681         bool signal = false;
 682         u32 pfncount = NUM_PAGES_SPANNED(multi_pagebuffer->offset,
 683                                          multi_pagebuffer->len);
 684
 685         if (pfncount > MAX_MULTIPAGE_BUFFER_COUNT)
 686                 return -EINVAL;
 687
 688         /*
 689          * Adjust the size down since vmbus_channel_packet_multipage_buffer is
 690          * the largest size we support
 691          */
 692         descsize = sizeof(struct vmbus_channel_packet_multipage_buffer) -
 693                           ((MAX_MULTIPAGE_BUFFER_COUNT - pfncount) *
 694                           sizeof(u64));
 695         packetlen = descsize + bufferlen;
 696         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 697
 698
 699         /* Setup the descriptor */
 700         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
 701         desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 702         desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
 703         desc.length8 = (u16)(packetlen_aligned >> 3);
 704         desc.transactionid = requestid;
 705         desc.rangecount = 1;
 706
 707         desc.range.len = multi_pagebuffer->len;
 708         desc.range.offset = multi_pagebuffer->offset;
 709
 710         memcpy(desc.range.pfn_array, multi_pagebuffer->pfn_array,
 711                pfncount * sizeof(u64));
 712
 713         bufferlist[0].iov_base = &desc;
 714         bufferlist[0].iov_len = descsize;
 715         bufferlist[1].iov_base = buffer;
 716         bufferlist[1].iov_len = bufferlen;
 717         bufferlist[2].iov_base = &aligned_data;
 718         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 719
 720         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
 721
 722         if (ret == 0 && signal)
 723                 vmbus_setevent(channel);
 724
 725         return ret;
 726 }
 727 EXPORT_SYMBOL_GPL(vmbus_sendpacket_multipagebuffer);
 728
 729 /**
 730  * vmbus_recvpacket() - Retrieve the user packet on the specified channel
 731  * @channel: Pointer to vmbus_channel structure.
 732  * @buffer: Pointer to the buffer you want to receive the data into.
 733  * @bufferlen: Maximum size of what the the buffer will hold
 734  * @buffer_actual_len: The actual size of the data after it was received
 735  * @requestid: Identifier of the request
 736  *
 737  * Receives directly from the hyper-v vmbus and puts the data it received
 738  * into Buffer. This will receive the data unparsed from hyper-v.
 739  *
 740  * Mainly used by Hyper-V drivers.
 741  */
 742 int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
 743                         u32 bufferlen, u32 *buffer_actual_len, u64 *requestid)
 744 {
 745         struct vmpacket_descriptor desc;
 746         u32 packetlen;
 747         u32 userlen;
 748         int ret;
 749         bool signal = false;
 750
 751         *buffer_actual_len = 0;
 752         *requestid = 0;
 753
 754
 755         ret = hv_ringbuffer_peek(&channel->inbound, &desc,
 756                              sizeof(struct vmpacket_descriptor));
 757         if (ret != 0)
 758                 return 0;
 759
 760         packetlen = desc.len8 << 3;
 761         userlen = packetlen - (desc.offset8 << 3);
 762
 763         *buffer_actual_len = userlen;
 764
 765         if (userlen > bufferlen) {
 766
 767                 pr_err("Buffer too small - got %d needs %d\n",
 768                            bufferlen, userlen);
 769                 return -ETOOSMALL;
 770         }
 771
 772         *requestid = desc.trans_id;
 773
 774         /* Copy over the packet to the user buffer */
 775         ret = hv_ringbuffer_read(&channel->inbound, buffer, userlen,
 776                              (desc.offset8 << 3), &signal);
 777
 778         if (signal)
 779                 vmbus_setevent(channel);
 780
 781         return 0;
 782 }
 783 EXPORT_SYMBOL(vmbus_recvpacket);
 784
 785 /*
 786  * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
 787  */
 788 int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
 789                               u32 bufferlen, u32 *buffer_actual_len,
 790                               u64 *requestid)
 791 {
 792         struct vmpacket_descriptor desc;
 793         u32 packetlen;
 794         int ret;
 795         bool signal = false;
 796
 797         *buffer_actual_len = 0;
 798         *requestid = 0;
 799
 800
 801         ret = hv_ringbuffer_peek(&channel->inbound, &desc,
 802                              sizeof(struct vmpacket_descriptor));
 803         if (ret != 0)
 804                 return 0;
 805
 806
 807         packetlen = desc.len8 << 3;
 808
 809         *buffer_actual_len = packetlen;
 810
 811         if (packetlen > bufferlen) {
 812                 pr_err("Buffer too small - needed %d bytes but "
 813                         "got space for only %d bytes\n",
 814                         packetlen, bufferlen);
 815                 return -ENOBUFS;
 816         }
 817
 818         *requestid = desc.trans_id;
 819
 820         /* Copy over the entire packet to the user buffer */
 821         ret = hv_ringbuffer_read(&channel->inbound, buffer, packetlen, 0,
 822                                  &signal);
 823
 824         if (signal)
 825                 vmbus_setevent(channel);
 826
 827         return ret;
 828 }
 829 EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);