kernel/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, err = 0;
  75         unsigned long t;
  76
  77         spin_lock_irqsave(&newchannel->lock, flags);
  78         if (newchannel->state == CHANNEL_OPEN_STATE) {
  79                 newchannel->state = CHANNEL_OPENING_STATE;
  80         } else {
  81                 spin_unlock_irqrestore(&newchannel->lock, flags);
  82                 return -EINVAL;
  83         }
  84         spin_unlock_irqrestore(&newchannel->lock, flags);
  85
  86         newchannel->onchannel_callback = onchannelcallback;
  87         newchannel->channel_callback_context = context;
  88
  89         /* Allocate the ring buffer */
  90         out = (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
  91                 get_order(send_ringbuffer_size + recv_ringbuffer_size));
  92
  93         if (!out) {
  94                 err = -ENOMEM;
  95                 goto error0;
  96         }
  97
  98         in = (void *)((unsigned long)out + send_ringbuffer_size);
  99
 100         newchannel->ringbuffer_pages = out;
 101         newchannel->ringbuffer_pagecount = (send_ringbuffer_size +
 102                                            recv_ringbuffer_size) >> PAGE_SHIFT;
 103
 104         ret = hv_ringbuffer_init(
 105                 &newchannel->outbound, out, send_ringbuffer_size);
 106
 107         if (ret != 0) {
 108                 err = ret;
 109                 goto error0;
 110         }
 111
 112         ret = hv_ringbuffer_init(
 113                 &newchannel->inbound, in, recv_ringbuffer_size);
 114         if (ret != 0) {
 115                 err = ret;
 116                 goto error0;
 117         }
 118
 119
 120         /* Establish the gpadl for the ring buffer */
 121         newchannel->ringbuffer_gpadlhandle = 0;
 122
 123         ret = vmbus_establish_gpadl(newchannel,
 124                                          newchannel->outbound.ring_buffer,
 125                                          send_ringbuffer_size +
 126                                          recv_ringbuffer_size,
 127                                          &newchannel->ringbuffer_gpadlhandle);
 128
 129         if (ret != 0) {
 130                 err = ret;
 131                 goto error0;
 132         }
 133
 134         /* Create and init the channel open message */
 135         open_info = kmalloc(sizeof(*open_info) +
 136                            sizeof(struct vmbus_channel_open_channel),
 137                            GFP_KERNEL);
 138         if (!open_info) {
 139                 err = -ENOMEM;
 140                 goto error_gpadl;
 141         }
 142
 143         init_completion(&open_info->waitevent);
 144
 145         open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
 146         open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
 147         open_msg->openid = newchannel->offermsg.child_relid;
 148         open_msg->child_relid = newchannel->offermsg.child_relid;
 149         open_msg->ringbuffer_gpadlhandle = newchannel->ringbuffer_gpadlhandle;
 150         open_msg->downstream_ringbuffer_pageoffset = send_ringbuffer_size >>
 151                                                   PAGE_SHIFT;
 152         open_msg->target_vp = newchannel->target_vp;
 153
 154         if (userdatalen > MAX_USER_DEFINED_BYTES) {
 155                 err = -EINVAL;
 156                 goto error_gpadl;
 157         }
 158
 159         if (userdatalen)
 160                 memcpy(open_msg->userdata, userdata, userdatalen);
 161
 162         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 163         list_add_tail(&open_info->msglistentry,
 164                       &vmbus_connection.chn_msg_list);
 165         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 166
 167         ret = vmbus_post_msg(open_msg,
 168                                sizeof(struct vmbus_channel_open_channel));
 169
 170         if (ret != 0) {
 171                 err = ret;
 172                 goto error1;
 173         }
 174
 175         t = wait_for_completion_timeout(&open_info->waitevent, 5*HZ);
 176         if (t == 0) {
 177                 err = -ETIMEDOUT;
 178                 goto error1;
 179         }
 180
 181
 182         if (open_info->response.open_result.status)
 183                 err = open_info->response.open_result.status;
 184
 185         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 186         list_del(&open_info->msglistentry);
 187         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 188
 189         if (err == 0)
 190                 newchannel->state = CHANNEL_OPENED_STATE;
 191
 192         kfree(open_info);
 193         return err;
 194
 195 error1:
 196         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 197         list_del(&open_info->msglistentry);
 198         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 199
 200 error_gpadl:
 201         vmbus_teardown_gpadl(newchannel, newchannel->ringbuffer_gpadlhandle);
 202
 203 error0:
 204         free_pages((unsigned long)out,
 205                 get_order(send_ringbuffer_size + recv_ringbuffer_size));
 206         kfree(open_info);
 207         newchannel->state = CHANNEL_OPEN_STATE;
 208         return err;
 209 }
 210 EXPORT_SYMBOL_GPL(vmbus_open);
 211
 212 /*
 213  * create_gpadl_header - Creates a gpadl for the specified buffer
 214  */
 215 static int create_gpadl_header(void *kbuffer, u32 size,
 216                                          struct vmbus_channel_msginfo **msginfo,
 217                                          u32 *messagecount)
 218 {
 219         int i;
 220         int pagecount;
 221         struct vmbus_channel_gpadl_header *gpadl_header;
 222         struct vmbus_channel_gpadl_body *gpadl_body;
 223         struct vmbus_channel_msginfo *msgheader;
 224         struct vmbus_channel_msginfo *msgbody = NULL;
 225         u32 msgsize;
 226
 227         int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
 228
 229         pagecount = size >> PAGE_SHIFT;
 230
 231         /* do we need a gpadl body msg */
 232         pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 233                   sizeof(struct vmbus_channel_gpadl_header) -
 234                   sizeof(struct gpa_range);
 235         pfncount = pfnsize / sizeof(u64);
 236
 237         if (pagecount > pfncount) {
 238                 /* we need a gpadl body */
 239                 /* fill in the header */
 240                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 241                           sizeof(struct vmbus_channel_gpadl_header) +
 242                           sizeof(struct gpa_range) + pfncount * sizeof(u64);
 243                 msgheader =  kzalloc(msgsize, GFP_KERNEL);
 244                 if (!msgheader)
 245                         goto nomem;
 246
 247                 INIT_LIST_HEAD(&msgheader->submsglist);
 248                 msgheader->msgsize = msgsize;
 249
 250                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 251                         msgheader->msg;
 252                 gpadl_header->rangecount = 1;
 253                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 254                                          pagecount * sizeof(u64);
 255                 gpadl_header->range[0].byte_offset = 0;
 256                 gpadl_header->range[0].byte_count = size;
 257                 for (i = 0; i < pfncount; i++)
 258                         gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
 259                                 kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 260                 *msginfo = msgheader;
 261                 *messagecount = 1;
 262
 263                 pfnsum = pfncount;
 264                 pfnleft = pagecount - pfncount;
 265
 266                 /* how many pfns can we fit */
 267                 pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 268                           sizeof(struct vmbus_channel_gpadl_body);
 269                 pfncount = pfnsize / sizeof(u64);
 270
 271                 /* fill in the body */
 272                 while (pfnleft) {
 273                         if (pfnleft > pfncount)
 274                                 pfncurr = pfncount;
 275                         else
 276                                 pfncurr = pfnleft;
 277
 278                         msgsize = sizeof(struct vmbus_channel_msginfo) +
 279                                   sizeof(struct vmbus_channel_gpadl_body) +
 280                                   pfncurr * sizeof(u64);
 281                         msgbody = kzalloc(msgsize, GFP_KERNEL);
 282
 283                         if (!msgbody) {
 284                                 struct vmbus_channel_msginfo *pos = NULL;
 285                                 struct vmbus_channel_msginfo *tmp = NULL;
 286                                 /*
 287                                  * Free up all the allocated messages.
 288                                  */
 289                                 list_for_each_entry_safe(pos, tmp,
 290                                         &msgheader->submsglist,
 291                                         msglistentry) {
 292
 293                                         list_del(&pos->msglistentry);
 294                                         kfree(pos);
 295                                 }
 296
 297                                 goto nomem;
 298                         }
 299
 300                         msgbody->msgsize = msgsize;
 301                         (*messagecount)++;
 302                         gpadl_body =
 303                                 (struct vmbus_channel_gpadl_body *)msgbody->msg;
 304
 305                         /*
 306                          * Gpadl is u32 and we are using a pointer which could
 307                          * be 64-bit
 308                          * This is governed by the guest/host protocol and
 309                          * so the hypervisor gurantees that this is ok.
 310                          */
 311                         for (i = 0; i < pfncurr; i++)
 312                                 gpadl_body->pfn[i] = slow_virt_to_phys(
 313                                         kbuffer + PAGE_SIZE * (pfnsum + i)) >>
 314                                         PAGE_SHIFT;
 315
 316                         /* add to msg header */
 317                         list_add_tail(&msgbody->msglistentry,
 318                                       &msgheader->submsglist);
 319                         pfnsum += pfncurr;
 320                         pfnleft -= pfncurr;
 321                 }
 322         } else {
 323                 /* everything fits in a header */
 324                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 325                           sizeof(struct vmbus_channel_gpadl_header) +
 326                           sizeof(struct gpa_range) + pagecount * sizeof(u64);
 327                 msgheader = kzalloc(msgsize, GFP_KERNEL);
 328                 if (msgheader == NULL)
 329                         goto nomem;
 330                 msgheader->msgsize = msgsize;
 331
 332                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 333                         msgheader->msg;
 334                 gpadl_header->rangecount = 1;
 335                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 336                                          pagecount * sizeof(u64);
 337                 gpadl_header->range[0].byte_offset = 0;
 338                 gpadl_header->range[0].byte_count = size;
 339                 for (i = 0; i < pagecount; i++)
 340                         gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
 341                                 kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 342
 343                 *msginfo = msgheader;
 344                 *messagecount = 1;
 345         }
 346
 347         return 0;
 348 nomem:
 349         kfree(msgheader);
 350         kfree(msgbody);
 351         return -ENOMEM;
 352 }
 353
 354 /*
 355  * vmbus_establish_gpadl - Estabish a GPADL for the specified buffer
 356  *
 357  * @channel: a channel
 358  * @kbuffer: from kmalloc or vmalloc
 359  * @size: page-size multiple
 360  * @gpadl_handle: some funky thing
 361  */
 362 int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
 363                                u32 size, u32 *gpadl_handle)
 364 {
 365         struct vmbus_channel_gpadl_header *gpadlmsg;
 366         struct vmbus_channel_gpadl_body *gpadl_body;
 367         struct vmbus_channel_msginfo *msginfo = NULL;
 368         struct vmbus_channel_msginfo *submsginfo;
 369         u32 msgcount;
 370         struct list_head *curr;
 371         u32 next_gpadl_handle;
 372         unsigned long flags;
 373         int ret = 0;
 374
 375         next_gpadl_handle =
 376                 (atomic_inc_return(&vmbus_connection.next_gpadl_handle) - 1);
 377
 378         ret = create_gpadl_header(kbuffer, size, &msginfo, &msgcount);
 379         if (ret)
 380                 return ret;
 381
 382         init_completion(&msginfo->waitevent);
 383
 384         gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
 385         gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
 386         gpadlmsg->child_relid = channel->offermsg.child_relid;
 387         gpadlmsg->gpadl = next_gpadl_handle;
 388
 389
 390         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 391         list_add_tail(&msginfo->msglistentry,
 392                       &vmbus_connection.chn_msg_list);
 393
 394         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 395
 396         ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize -
 397                                sizeof(*msginfo));
 398         if (ret != 0)
 399                 goto cleanup;
 400
 401         if (msgcount > 1) {
 402                 list_for_each(curr, &msginfo->submsglist) {
 403
 404                         submsginfo = (struct vmbus_channel_msginfo *)curr;
 405                         gpadl_body =
 406                              (struct vmbus_channel_gpadl_body *)submsginfo->msg;
 407
 408                         gpadl_body->header.msgtype =
 409                                 CHANNELMSG_GPADL_BODY;
 410                         gpadl_body->gpadl = next_gpadl_handle;
 411
 412                         ret = vmbus_post_msg(gpadl_body,
 413                                                submsginfo->msgsize -
 414                                                sizeof(*submsginfo));
 415                         if (ret != 0)
 416                                 goto cleanup;
 417
 418                 }
 419         }
 420         wait_for_completion(&msginfo->waitevent);
 421
 422         /* At this point, we received the gpadl created msg */
 423         *gpadl_handle = gpadlmsg->gpadl;
 424
 425 cleanup:
 426         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 427         list_del(&msginfo->msglistentry);
 428         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 429
 430         kfree(msginfo);
 431         return ret;
 432 }
 433 EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
 434
 435 /*
 436  * vmbus_teardown_gpadl -Teardown the specified GPADL handle
 437  */
 438 int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
 439 {
 440         struct vmbus_channel_gpadl_teardown *msg;
 441         struct vmbus_channel_msginfo *info;
 442         unsigned long flags;
 443         int ret;
 444
 445         info = kmalloc(sizeof(*info) +
 446                        sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
 447         if (!info)
 448                 return -ENOMEM;
 449
 450         init_completion(&info->waitevent);
 451
 452         msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
 453
 454         msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
 455         msg->child_relid = channel->offermsg.child_relid;
 456         msg->gpadl = gpadl_handle;
 457
 458         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 459         list_add_tail(&info->msglistentry,
 460                       &vmbus_connection.chn_msg_list);
 461         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 462         ret = vmbus_post_msg(msg,
 463                                sizeof(struct vmbus_channel_gpadl_teardown));
 464
 465         if (ret)
 466                 goto post_msg_err;
 467
 468         wait_for_completion(&info->waitevent);
 469
 470 post_msg_err:
 471         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 472         list_del(&info->msglistentry);
 473         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 474
 475         kfree(info);
 476         return ret;
 477 }
 478 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
 479
 480 static void reset_channel_cb(void *arg)
 481 {
 482         struct vmbus_channel *channel = arg;
 483
 484         channel->onchannel_callback = NULL;
 485 }
 486
 487 static int vmbus_close_internal(struct vmbus_channel *channel)
 488 {
 489         struct vmbus_channel_close_channel *msg;
 490         int ret;
 491
 492         channel->state = CHANNEL_OPEN_STATE;
 493         channel->sc_creation_callback = NULL;
 494         /* Stop callback and cancel the timer asap */
 495         if (channel->target_cpu != get_cpu()) {
 496                 put_cpu();
 497                 smp_call_function_single(channel->target_cpu, reset_channel_cb,
 498                                          channel, true);
 499         } else {
 500                 reset_channel_cb(channel);
 501                 put_cpu();
 502         }
 503
 504         /* Send a closing message */
 505
 506         msg = &channel->close_msg.msg;
 507
 508         msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
 509         msg->child_relid = channel->offermsg.child_relid;
 510
 511         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel));
 512
 513         if (ret) {
 514                 pr_err("Close failed: close post msg return is %d\n", ret);
 515                 /*
 516                  * If we failed to post the close msg,
 517                  * it is perhaps better to leak memory.
 518                  */
 519                 return ret;
 520         }
 521
 522         /* Tear down the gpadl for the channel's ring buffer */
 523         if (channel->ringbuffer_gpadlhandle) {
 524                 ret = vmbus_teardown_gpadl(channel,
 525                                            channel->ringbuffer_gpadlhandle);
 526                 if (ret) {
 527                         pr_err("Close failed: teardown gpadl return %d\n", ret);
 528                         /*
 529                          * If we failed to teardown gpadl,
 530                          * it is perhaps better to leak memory.
 531                          */
 532                         return ret;
 533                 }
 534         }
 535
 536         /* Cleanup the ring buffers for this channel */
 537         hv_ringbuffer_cleanup(&channel->outbound);
 538         hv_ringbuffer_cleanup(&channel->inbound);
 539
 540         free_pages((unsigned long)channel->ringbuffer_pages,
 541                 get_order(channel->ringbuffer_pagecount * PAGE_SIZE));
 542
 543         /*
 544          * If the channel has been rescinded; process device removal.
 545          */
 546         if (channel->rescind)
 547                 hv_process_channel_removal(channel,
 548                                            channel->offermsg.child_relid);
 549         return ret;
 550 }
 551
 552 /*
 553  * vmbus_close - Close the specified channel
 554  */
 555 void vmbus_close(struct vmbus_channel *channel)
 556 {
 557         struct list_head *cur, *tmp;
 558         struct vmbus_channel *cur_channel;
 559
 560         if (channel->primary_channel != NULL) {
 561                 /*
 562                  * We will only close sub-channels when
 563                  * the primary is closed.
 564                  */
 565                 return;
 566         }
 567         /*
 568          * Close all the sub-channels first and then close the
 569          * primary channel.
 570          */
 571         list_for_each_safe(cur, tmp, &channel->sc_list) {
 572                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 573                 if (cur_channel->state != CHANNEL_OPENED_STATE)
 574                         continue;
 575                 vmbus_close_internal(cur_channel);
 576         }
 577         /*
 578          * Now close the primary.
 579          */
 580         vmbus_close_internal(channel);
 581 }
 582 EXPORT_SYMBOL_GPL(vmbus_close);
 583
 584 int vmbus_sendpacket_ctl(struct vmbus_channel *channel, void *buffer,
 585                            u32 bufferlen, u64 requestid,
 586                            enum vmbus_packet_type type, u32 flags, bool kick_q)
 587 {
 588         struct vmpacket_descriptor desc;
 589         u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
 590         u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 591         struct kvec bufferlist[3];
 592         u64 aligned_data = 0;
 593         int ret;
 594         bool signal = false;
 595
 596
 597         /* Setup the descriptor */
 598         desc.type = type; /* VmbusPacketTypeDataInBand; */
 599         desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
 600         /* in 8-bytes granularity */
 601         desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3;
 602         desc.len8 = (u16)(packetlen_aligned >> 3);
 603         desc.trans_id = requestid;
 604
 605         bufferlist[0].iov_base = &desc;
 606         bufferlist[0].iov_len = sizeof(struct vmpacket_descriptor);
 607         bufferlist[1].iov_base = buffer;
 608         bufferlist[1].iov_len = bufferlen;
 609         bufferlist[2].iov_base = &aligned_data;
 610         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 611
 612         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
 613
 614         /*
 615          * Signalling the host is conditional on many factors:
 616          * 1. The ring state changed from being empty to non-empty.
 617          *    This is tracked by the variable "signal".
 618          * 2. The variable kick_q tracks if more data will be placed
 619          *    on the ring. We will not signal if more data is
 620          *    to be placed.
 621          *
 622          * If we cannot write to the ring-buffer; signal the host
 623          * even if we may not have written anything. This is a rare
 624          * enough condition that it should not matter.
 625          */
 626         if (((ret == 0) && kick_q && signal) || (ret))
 627                 vmbus_setevent(channel);
 628
 629         return ret;
 630 }
 631 EXPORT_SYMBOL(vmbus_sendpacket_ctl);
 632
 633 /**
 634  * vmbus_sendpacket() - Send the specified buffer on the given channel
 635  * @channel: Pointer to vmbus_channel structure.
 636  * @buffer: Pointer to the buffer you want to receive the data into.
 637  * @bufferlen: Maximum size of what the the buffer will hold
 638  * @requestid: Identifier of the request
 639  * @type: Type of packet that is being send e.g. negotiate, time
 640  * packet etc.
 641  *
 642  * Sends data in @buffer directly to hyper-v via the vmbus
 643  * This will send the data unparsed to hyper-v.
 644  *
 645  * Mainly used by Hyper-V drivers.
 646  */
 647 int vmbus_sendpacket(struct vmbus_channel *channel, void *buffer,
 648                            u32 bufferlen, u64 requestid,
 649                            enum vmbus_packet_type type, u32 flags)
 650 {
 651         return vmbus_sendpacket_ctl(channel, buffer, bufferlen, requestid,
 652                                     type, flags, true);
 653 }
 654 EXPORT_SYMBOL(vmbus_sendpacket);
 655
 656 /*
 657  * vmbus_sendpacket_pagebuffer_ctl - Send a range of single-page buffer
 658  * packets using a GPADL Direct packet type. This interface allows you
 659  * to control notifying the host. This will be useful for sending
 660  * batched data. Also the sender can control the send flags
 661  * explicitly.
 662  */
 663 int vmbus_sendpacket_pagebuffer_ctl(struct vmbus_channel *channel,
 664                                      struct hv_page_buffer pagebuffers[],
 665                                      u32 pagecount, void *buffer, u32 bufferlen,
 666                                      u64 requestid,
 667                                      u32 flags,
 668                                      bool kick_q)
 669 {
 670         int ret;
 671         int i;
 672         struct vmbus_channel_packet_page_buffer desc;
 673         u32 descsize;
 674         u32 packetlen;
 675         u32 packetlen_aligned;
 676         struct kvec bufferlist[3];
 677         u64 aligned_data = 0;
 678         bool signal = false;
 679
 680         if (pagecount > MAX_PAGE_BUFFER_COUNT)
 681                 return -EINVAL;
 682
 683
 684         /*
 685          * Adjust the size down since vmbus_channel_packet_page_buffer is the
 686          * largest size we support
 687          */
 688         descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
 689                           ((MAX_PAGE_BUFFER_COUNT - pagecount) *
 690                           sizeof(struct hv_page_buffer));
 691         packetlen = descsize + bufferlen;
 692         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 693
 694         /* Setup the descriptor */
 695         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
 696         desc.flags = flags;
 697         desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
 698         desc.length8 = (u16)(packetlen_aligned >> 3);
 699         desc.transactionid = requestid;
 700         desc.rangecount = pagecount;
 701
 702         for (i = 0; i < pagecount; i++) {
 703                 desc.range[i].len = pagebuffers[i].len;
 704                 desc.range[i].offset = pagebuffers[i].offset;
 705                 desc.range[i].pfn        = pagebuffers[i].pfn;
 706         }
 707
 708         bufferlist[0].iov_base = &desc;
 709         bufferlist[0].iov_len = descsize;
 710         bufferlist[1].iov_base = buffer;
 711         bufferlist[1].iov_len = bufferlen;
 712         bufferlist[2].iov_base = &aligned_data;
 713         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 714
 715         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
 716
 717         /*
 718          * Signalling the host is conditional on many factors:
 719          * 1. The ring state changed from being empty to non-empty.
 720          *    This is tracked by the variable "signal".
 721          * 2. The variable kick_q tracks if more data will be placed
 722          *    on the ring. We will not signal if more data is
 723          *    to be placed.
 724          *
 725          * If we cannot write to the ring-buffer; signal the host
 726          * even if we may not have written anything. This is a rare
 727          * enough condition that it should not matter.
 728          */
 729         if (((ret == 0) && kick_q && signal) || (ret))
 730                 vmbus_setevent(channel);
 731
 732         return ret;
 733 }
 734 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer_ctl);
 735
 736 /*
 737  * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
 738  * packets using a GPADL Direct packet type.
 739  */
 740 int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
 741                                      struct hv_page_buffer pagebuffers[],
 742                                      u32 pagecount, void *buffer, u32 bufferlen,
 743                                      u64 requestid)
 744 {
 745         u32 flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 746         return vmbus_sendpacket_pagebuffer_ctl(channel, pagebuffers, pagecount,
 747                                                buffer, bufferlen, requestid,
 748                                                flags, true);
 749
 750 }
 751 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
 752
 753 /*
 754  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
 755  * using a GPADL Direct packet type.
 756  * The buffer includes the vmbus descriptor.
 757  */
 758 int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
 759                               struct vmbus_packet_mpb_array *desc,
 760                               u32 desc_size,
 761                               void *buffer, u32 bufferlen, u64 requestid)
 762 {
 763         int ret;
 764         u32 packetlen;
 765         u32 packetlen_aligned;
 766         struct kvec bufferlist[3];
 767         u64 aligned_data = 0;
 768         bool signal = false;
 769
 770         packetlen = desc_size + bufferlen;
 771         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 772
 773         /* Setup the descriptor */
 774         desc->type = VM_PKT_DATA_USING_GPA_DIRECT;
 775         desc->flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 776         desc->dataoffset8 = desc_size >> 3; /* in 8-bytes grandularity */
 777         desc->length8 = (u16)(packetlen_aligned >> 3);
 778         desc->transactionid = requestid;
 779         desc->rangecount = 1;
 780
 781         bufferlist[0].iov_base = desc;
 782         bufferlist[0].iov_len = desc_size;
 783         bufferlist[1].iov_base = buffer;
 784         bufferlist[1].iov_len = bufferlen;
 785         bufferlist[2].iov_base = &aligned_data;
 786         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 787
 788         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
 789
 790         if (ret == 0 && signal)
 791                 vmbus_setevent(channel);
 792
 793         return ret;
 794 }
 795 EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc);
 796
 797 /*
 798  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
 799  * using a GPADL Direct packet type.
 800  */
 801 int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
 802                                 struct hv_multipage_buffer *multi_pagebuffer,
 803                                 void *buffer, u32 bufferlen, u64 requestid)
 804 {
 805         int ret;
 806         struct vmbus_channel_packet_multipage_buffer desc;
 807         u32 descsize;
 808         u32 packetlen;
 809         u32 packetlen_aligned;
 810         struct kvec bufferlist[3];
 811         u64 aligned_data = 0;
 812         bool signal = false;
 813         u32 pfncount = NUM_PAGES_SPANNED(multi_pagebuffer->offset,
 814                                          multi_pagebuffer->len);
 815
 816         if (pfncount > MAX_MULTIPAGE_BUFFER_COUNT)
 817                 return -EINVAL;
 818
 819         /*
 820          * Adjust the size down since vmbus_channel_packet_multipage_buffer is
 821          * the largest size we support
 822          */
 823         descsize = sizeof(struct vmbus_channel_packet_multipage_buffer) -
 824                           ((MAX_MULTIPAGE_BUFFER_COUNT - pfncount) *
 825                           sizeof(u64));
 826         packetlen = descsize + bufferlen;
 827         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 828
 829
 830         /* Setup the descriptor */
 831         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
 832         desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 833         desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
 834         desc.length8 = (u16)(packetlen_aligned >> 3);
 835         desc.transactionid = requestid;
 836         desc.rangecount = 1;
 837
 838         desc.range.len = multi_pagebuffer->len;
 839         desc.range.offset = multi_pagebuffer->offset;
 840
 841         memcpy(desc.range.pfn_array, multi_pagebuffer->pfn_array,
 842                pfncount * sizeof(u64));
 843
 844         bufferlist[0].iov_base = &desc;
 845         bufferlist[0].iov_len = descsize;
 846         bufferlist[1].iov_base = buffer;
 847         bufferlist[1].iov_len = bufferlen;
 848         bufferlist[2].iov_base = &aligned_data;
 849         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 850
 851         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
 852
 853         if (ret == 0 && signal)
 854                 vmbus_setevent(channel);
 855
 856         return ret;
 857 }
 858 EXPORT_SYMBOL_GPL(vmbus_sendpacket_multipagebuffer);
 859
 860 /**
 861  * vmbus_recvpacket() - Retrieve the user packet on the specified channel
 862  * @channel: Pointer to vmbus_channel structure.
 863  * @buffer: Pointer to the buffer you want to receive the data into.
 864  * @bufferlen: Maximum size of what the the buffer will hold
 865  * @buffer_actual_len: The actual size of the data after it was received
 866  * @requestid: Identifier of the request
 867  *
 868  * Receives directly from the hyper-v vmbus and puts the data it received
 869  * into Buffer. This will receive the data unparsed from hyper-v.
 870  *
 871  * Mainly used by Hyper-V drivers.
 872  */
 873 int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
 874                         u32 bufferlen, u32 *buffer_actual_len, u64 *requestid)
 875 {
 876         struct vmpacket_descriptor desc;
 877         u32 packetlen;
 878         u32 userlen;
 879         int ret;
 880         bool signal = false;
 881
 882         *buffer_actual_len = 0;
 883         *requestid = 0;
 884
 885
 886         ret = hv_ringbuffer_peek(&channel->inbound, &desc,
 887                              sizeof(struct vmpacket_descriptor));
 888         if (ret != 0)
 889                 return 0;
 890
 891         packetlen = desc.len8 << 3;
 892         userlen = packetlen - (desc.offset8 << 3);
 893
 894         *buffer_actual_len = userlen;
 895
 896         if (userlen > bufferlen) {
 897
 898                 pr_err("Buffer too small - got %d needs %d\n",
 899                            bufferlen, userlen);
 900                 return -ETOOSMALL;
 901         }
 902
 903         *requestid = desc.trans_id;
 904
 905         /* Copy over the packet to the user buffer */
 906         ret = hv_ringbuffer_read(&channel->inbound, buffer, userlen,
 907                              (desc.offset8 << 3), &signal);
 908
 909         if (signal)
 910                 vmbus_setevent(channel);
 911
 912         return 0;
 913 }
 914 EXPORT_SYMBOL(vmbus_recvpacket);
 915
 916 /*
 917  * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
 918  */
 919 int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
 920                               u32 bufferlen, u32 *buffer_actual_len,
 921                               u64 *requestid)
 922 {
 923         struct vmpacket_descriptor desc;
 924         u32 packetlen;
 925         int ret;
 926         bool signal = false;
 927
 928         *buffer_actual_len = 0;
 929         *requestid = 0;
 930
 931
 932         ret = hv_ringbuffer_peek(&channel->inbound, &desc,
 933                              sizeof(struct vmpacket_descriptor));
 934         if (ret != 0)
 935                 return 0;
 936
 937
 938         packetlen = desc.len8 << 3;
 939
 940         *buffer_actual_len = packetlen;
 941
 942         if (packetlen > bufferlen)
 943                 return -ENOBUFS;
 944
 945         *requestid = desc.trans_id;
 946
 947         /* Copy over the entire packet to the user buffer */
 948         ret = hv_ringbuffer_read(&channel->inbound, buffer, packetlen, 0,
 949                                  &signal);
 950
 951         if (signal)
 952                 vmbus_setevent(channel);
 953
 954         return ret;
 955 }
 956 EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);