drivers/hv/channel.c

   1 /*
   2  * Copyright (c) 2009, Microsoft Corporation.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms and conditions of the GNU General Public License,
   6  * version 2, as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  15  * Place - Suite 330, Boston, MA 02111-1307 USA.
  16  *
  17  * Authors:
  18  *   Haiyang Zhang <haiyangz@microsoft.com>
  19  *   Hank Janssen  <hjanssen@microsoft.com>
  20  */
  21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  22
  23 #include <linux/kernel.h>
  24 #include <linux/sched.h>
  25 #include <linux/wait.h>
  26 #include <linux/mm.h>
  27 #include <linux/slab.h>
  28 #include <linux/module.h>
  29 #include <linux/hyperv.h>
  30 #include <linux/uio.h>
  31 #include <linux/interrupt.h>
  32
  33 #include "hyperv_vmbus.h"
  34
  35 #define NUM_PAGES_SPANNED(addr, len) \
  36 ((PAGE_ALIGN(addr + len) >> PAGE_SHIFT) - (addr >> PAGE_SHIFT))
  37
  38 /*
  39  * vmbus_setevent- Trigger an event notification on the specified
  40  * channel.
  41  */
  42 static void vmbus_setevent(struct vmbus_channel *channel)
  43 {
  44         struct hv_monitor_page *monitorpage;
  45
  46         if (channel->offermsg.monitor_allocated) {
  47                 /* Each u32 represents 32 channels */
  48                 sync_set_bit(channel->offermsg.child_relid & 31,
  49                         (unsigned long *) vmbus_connection.send_int_page +
  50                         (channel->offermsg.child_relid >> 5));
  51
  52                 /* Get the child to parent monitor page */
  53                 monitorpage = vmbus_connection.monitor_pages[1];
  54
  55                 sync_set_bit(channel->monitor_bit,
  56                         (unsigned long *)&monitorpage->trigger_group
  57                                         [channel->monitor_grp].pending);
  58
  59         } else {
  60                 vmbus_set_event(channel);
  61         }
  62 }
  63
  64 /*
  65  * vmbus_open - Open the specified channel.
  66  */
  67 int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
  68                      u32 recv_ringbuffer_size, void *userdata, u32 userdatalen,
  69                      void (*onchannelcallback)(void *context), void *context)
  70 {
  71         struct vmbus_channel_open_channel *open_msg;
  72         struct vmbus_channel_msginfo *open_info = NULL;
  73         void *in, *out;
  74         unsigned long flags;
  75         int ret, err = 0;
  76         unsigned long t;
  77         struct page *page;
  78
  79         spin_lock_irqsave(&newchannel->lock, flags);
  80         if (newchannel->state == CHANNEL_OPEN_STATE) {
  81                 newchannel->state = CHANNEL_OPENING_STATE;
  82         } else {
  83                 spin_unlock_irqrestore(&newchannel->lock, flags);
  84                 return -EINVAL;
  85         }
  86         spin_unlock_irqrestore(&newchannel->lock, flags);
  87
  88         newchannel->onchannel_callback = onchannelcallback;
  89         newchannel->channel_callback_context = context;
  90
  91         /* Allocate the ring buffer */
  92         page = alloc_pages_node(cpu_to_node(newchannel->target_cpu),
  93                                 GFP_KERNEL|__GFP_ZERO,
  94                                 get_order(send_ringbuffer_size +
  95                                 recv_ringbuffer_size));
  96
  97         if (!page)
  98                 out = (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
  99                                                get_order(send_ringbuffer_size +
 100                                                recv_ringbuffer_size));
 101         else
 102                 out = (void *)page_address(page);
 103
 104         if (!out) {
 105                 err = -ENOMEM;
 106                 goto error0;
 107         }
 108
 109         in = (void *)((unsigned long)out + send_ringbuffer_size);
 110
 111         newchannel->ringbuffer_pages = out;
 112         newchannel->ringbuffer_pagecount = (send_ringbuffer_size +
 113                                            recv_ringbuffer_size) >> PAGE_SHIFT;
 114
 115         ret = hv_ringbuffer_init(
 116                 &newchannel->outbound, out, send_ringbuffer_size);
 117
 118         if (ret != 0) {
 119                 err = ret;
 120                 goto error0;
 121         }
 122
 123         ret = hv_ringbuffer_init(
 124                 &newchannel->inbound, in, recv_ringbuffer_size);
 125         if (ret != 0) {
 126                 err = ret;
 127                 goto error0;
 128         }
 129
 130
 131         /* Establish the gpadl for the ring buffer */
 132         newchannel->ringbuffer_gpadlhandle = 0;
 133
 134         ret = vmbus_establish_gpadl(newchannel,
 135                                          newchannel->outbound.ring_buffer,
 136                                          send_ringbuffer_size +
 137                                          recv_ringbuffer_size,
 138                                          &newchannel->ringbuffer_gpadlhandle);
 139
 140         if (ret != 0) {
 141                 err = ret;
 142                 goto error0;
 143         }
 144
 145         /* Create and init the channel open message */
 146         open_info = kmalloc(sizeof(*open_info) +
 147                            sizeof(struct vmbus_channel_open_channel),
 148                            GFP_KERNEL);
 149         if (!open_info) {
 150                 err = -ENOMEM;
 151                 goto error_gpadl;
 152         }
 153
 154         init_completion(&open_info->waitevent);
 155
 156         open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
 157         open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
 158         open_msg->openid = newchannel->offermsg.child_relid;
 159         open_msg->child_relid = newchannel->offermsg.child_relid;
 160         open_msg->ringbuffer_gpadlhandle = newchannel->ringbuffer_gpadlhandle;
 161         open_msg->downstream_ringbuffer_pageoffset = send_ringbuffer_size >>
 162                                                   PAGE_SHIFT;
 163         open_msg->target_vp = newchannel->target_vp;
 164
 165         if (userdatalen > MAX_USER_DEFINED_BYTES) {
 166                 err = -EINVAL;
 167                 goto error_gpadl;
 168         }
 169
 170         if (userdatalen)
 171                 memcpy(open_msg->userdata, userdata, userdatalen);
 172
 173         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 174         list_add_tail(&open_info->msglistentry,
 175                       &vmbus_connection.chn_msg_list);
 176         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 177
 178         ret = vmbus_post_msg(open_msg,
 179                                sizeof(struct vmbus_channel_open_channel));
 180
 181         if (ret != 0) {
 182                 err = ret;
 183                 goto error1;
 184         }
 185
 186         t = wait_for_completion_timeout(&open_info->waitevent, 5*HZ);
 187         if (t == 0) {
 188                 err = -ETIMEDOUT;
 189                 goto error1;
 190         }
 191
 192         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 193         list_del(&open_info->msglistentry);
 194         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 195
 196         if (open_info->response.open_result.status) {
 197                 err = -EAGAIN;
 198                 goto error_gpadl;
 199         }
 200
 201         newchannel->state = CHANNEL_OPENED_STATE;
 202         kfree(open_info);
 203         return 0;
 204
 205 error1:
 206         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 207         list_del(&open_info->msglistentry);
 208         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 209
 210 error_gpadl:
 211         vmbus_teardown_gpadl(newchannel, newchannel->ringbuffer_gpadlhandle);
 212
 213 error0:
 214         free_pages((unsigned long)out,
 215                 get_order(send_ringbuffer_size + recv_ringbuffer_size));
 216         kfree(open_info);
 217         newchannel->state = CHANNEL_OPEN_STATE;
 218         return err;
 219 }
 220 EXPORT_SYMBOL_GPL(vmbus_open);
 221
 222 /*
 223  * create_gpadl_header - Creates a gpadl for the specified buffer
 224  */
 225 static int create_gpadl_header(void *kbuffer, u32 size,
 226                                          struct vmbus_channel_msginfo **msginfo,
 227                                          u32 *messagecount)
 228 {
 229         int i;
 230         int pagecount;
 231         struct vmbus_channel_gpadl_header *gpadl_header;
 232         struct vmbus_channel_gpadl_body *gpadl_body;
 233         struct vmbus_channel_msginfo *msgheader;
 234         struct vmbus_channel_msginfo *msgbody = NULL;
 235         u32 msgsize;
 236
 237         int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
 238
 239         pagecount = size >> PAGE_SHIFT;
 240
 241         /* do we need a gpadl body msg */
 242         pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 243                   sizeof(struct vmbus_channel_gpadl_header) -
 244                   sizeof(struct gpa_range);
 245         pfncount = pfnsize / sizeof(u64);
 246
 247         if (pagecount > pfncount) {
 248                 /* we need a gpadl body */
 249                 /* fill in the header */
 250                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 251                           sizeof(struct vmbus_channel_gpadl_header) +
 252                           sizeof(struct gpa_range) + pfncount * sizeof(u64);
 253                 msgheader =  kzalloc(msgsize, GFP_KERNEL);
 254                 if (!msgheader)
 255                         goto nomem;
 256
 257                 INIT_LIST_HEAD(&msgheader->submsglist);
 258                 msgheader->msgsize = msgsize;
 259
 260                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 261                         msgheader->msg;
 262                 gpadl_header->rangecount = 1;
 263                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 264                                          pagecount * sizeof(u64);
 265                 gpadl_header->range[0].byte_offset = 0;
 266                 gpadl_header->range[0].byte_count = size;
 267                 for (i = 0; i < pfncount; i++)
 268                         gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
 269                                 kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 270                 *msginfo = msgheader;
 271                 *messagecount = 1;
 272
 273                 pfnsum = pfncount;
 274                 pfnleft = pagecount - pfncount;
 275
 276                 /* how many pfns can we fit */
 277                 pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 278                           sizeof(struct vmbus_channel_gpadl_body);
 279                 pfncount = pfnsize / sizeof(u64);
 280
 281                 /* fill in the body */
 282                 while (pfnleft) {
 283                         if (pfnleft > pfncount)
 284                                 pfncurr = pfncount;
 285                         else
 286                                 pfncurr = pfnleft;
 287
 288                         msgsize = sizeof(struct vmbus_channel_msginfo) +
 289                                   sizeof(struct vmbus_channel_gpadl_body) +
 290                                   pfncurr * sizeof(u64);
 291                         msgbody = kzalloc(msgsize, GFP_KERNEL);
 292
 293                         if (!msgbody) {
 294                                 struct vmbus_channel_msginfo *pos = NULL;
 295                                 struct vmbus_channel_msginfo *tmp = NULL;
 296                                 /*
 297                                  * Free up all the allocated messages.
 298                                  */
 299                                 list_for_each_entry_safe(pos, tmp,
 300                                         &msgheader->submsglist,
 301                                         msglistentry) {
 302
 303                                         list_del(&pos->msglistentry);
 304                                         kfree(pos);
 305                                 }
 306
 307                                 goto nomem;
 308                         }
 309
 310                         msgbody->msgsize = msgsize;
 311                         (*messagecount)++;
 312                         gpadl_body =
 313                                 (struct vmbus_channel_gpadl_body *)msgbody->msg;
 314
 315                         /*
 316                          * Gpadl is u32 and we are using a pointer which could
 317                          * be 64-bit
 318                          * This is governed by the guest/host protocol and
 319                          * so the hypervisor gurantees that this is ok.
 320                          */
 321                         for (i = 0; i < pfncurr; i++)
 322                                 gpadl_body->pfn[i] = slow_virt_to_phys(
 323                                         kbuffer + PAGE_SIZE * (pfnsum + i)) >>
 324                                         PAGE_SHIFT;
 325
 326                         /* add to msg header */
 327                         list_add_tail(&msgbody->msglistentry,
 328                                       &msgheader->submsglist);
 329                         pfnsum += pfncurr;
 330                         pfnleft -= pfncurr;
 331                 }
 332         } else {
 333                 /* everything fits in a header */
 334                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 335                           sizeof(struct vmbus_channel_gpadl_header) +
 336                           sizeof(struct gpa_range) + pagecount * sizeof(u64);
 337                 msgheader = kzalloc(msgsize, GFP_KERNEL);
 338                 if (msgheader == NULL)
 339                         goto nomem;
 340                 msgheader->msgsize = msgsize;
 341
 342                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 343                         msgheader->msg;
 344                 gpadl_header->rangecount = 1;
 345                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 346                                          pagecount * sizeof(u64);
 347                 gpadl_header->range[0].byte_offset = 0;
 348                 gpadl_header->range[0].byte_count = size;
 349                 for (i = 0; i < pagecount; i++)
 350                         gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
 351                                 kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 352
 353                 *msginfo = msgheader;
 354                 *messagecount = 1;
 355         }
 356
 357         return 0;
 358 nomem:
 359         kfree(msgheader);
 360         kfree(msgbody);
 361         return -ENOMEM;
 362 }
 363
 364 /*
 365  * vmbus_establish_gpadl - Estabish a GPADL for the specified buffer
 366  *
 367  * @channel: a channel
 368  * @kbuffer: from kmalloc or vmalloc
 369  * @size: page-size multiple
 370  * @gpadl_handle: some funky thing
 371  */
 372 int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
 373                                u32 size, u32 *gpadl_handle)
 374 {
 375         struct vmbus_channel_gpadl_header *gpadlmsg;
 376         struct vmbus_channel_gpadl_body *gpadl_body;
 377         struct vmbus_channel_msginfo *msginfo = NULL;
 378         struct vmbus_channel_msginfo *submsginfo;
 379         u32 msgcount;
 380         struct list_head *curr;
 381         u32 next_gpadl_handle;
 382         unsigned long flags;
 383         int ret = 0;
 384
 385         next_gpadl_handle =
 386                 (atomic_inc_return(&vmbus_connection.next_gpadl_handle) - 1);
 387
 388         ret = create_gpadl_header(kbuffer, size, &msginfo, &msgcount);
 389         if (ret)
 390                 return ret;
 391
 392         init_completion(&msginfo->waitevent);
 393
 394         gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
 395         gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
 396         gpadlmsg->child_relid = channel->offermsg.child_relid;
 397         gpadlmsg->gpadl = next_gpadl_handle;
 398
 399
 400         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 401         list_add_tail(&msginfo->msglistentry,
 402                       &vmbus_connection.chn_msg_list);
 403
 404         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 405
 406         ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize -
 407                                sizeof(*msginfo));
 408         if (ret != 0)
 409                 goto cleanup;
 410
 411         if (msgcount > 1) {
 412                 list_for_each(curr, &msginfo->submsglist) {
 413
 414                         submsginfo = (struct vmbus_channel_msginfo *)curr;
 415                         gpadl_body =
 416                              (struct vmbus_channel_gpadl_body *)submsginfo->msg;
 417
 418                         gpadl_body->header.msgtype =
 419                                 CHANNELMSG_GPADL_BODY;
 420                         gpadl_body->gpadl = next_gpadl_handle;
 421
 422                         ret = vmbus_post_msg(gpadl_body,
 423                                                submsginfo->msgsize -
 424                                                sizeof(*submsginfo));
 425                         if (ret != 0)
 426                                 goto cleanup;
 427
 428                 }
 429         }
 430         wait_for_completion(&msginfo->waitevent);
 431
 432         /* At this point, we received the gpadl created msg */
 433         *gpadl_handle = gpadlmsg->gpadl;
 434
 435 cleanup:
 436         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 437         list_del(&msginfo->msglistentry);
 438         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 439
 440         kfree(msginfo);
 441         return ret;
 442 }
 443 EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
 444
 445 /*
 446  * vmbus_teardown_gpadl -Teardown the specified GPADL handle
 447  */
 448 int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
 449 {
 450         struct vmbus_channel_gpadl_teardown *msg;
 451         struct vmbus_channel_msginfo *info;
 452         unsigned long flags;
 453         int ret;
 454
 455         info = kmalloc(sizeof(*info) +
 456                        sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
 457         if (!info)
 458                 return -ENOMEM;
 459
 460         init_completion(&info->waitevent);
 461
 462         msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
 463
 464         msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
 465         msg->child_relid = channel->offermsg.child_relid;
 466         msg->gpadl = gpadl_handle;
 467
 468         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 469         list_add_tail(&info->msglistentry,
 470                       &vmbus_connection.chn_msg_list);
 471         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 472         ret = vmbus_post_msg(msg,
 473                                sizeof(struct vmbus_channel_gpadl_teardown));
 474
 475         if (ret)
 476                 goto post_msg_err;
 477
 478         wait_for_completion(&info->waitevent);
 479
 480 post_msg_err:
 481         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 482         list_del(&info->msglistentry);
 483         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 484
 485         kfree(info);
 486         return ret;
 487 }
 488 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
 489
 490 static void reset_channel_cb(void *arg)
 491 {
 492         struct vmbus_channel *channel = arg;
 493
 494         channel->onchannel_callback = NULL;
 495 }
 496
 497 static int vmbus_close_internal(struct vmbus_channel *channel)
 498 {
 499         struct vmbus_channel_close_channel *msg;
 500         struct tasklet_struct *tasklet;
 501         int ret;
 502
 503         /*
 504          * process_chn_event(), running in the tasklet, can race
 505          * with vmbus_close_internal() in the case of SMP guest, e.g., when
 506          * the former is accessing channel->inbound.ring_buffer, the latter
 507          * could be freeing the ring_buffer pages.
 508          *
 509          * To resolve the race, we can serialize them by disabling the
 510          * tasklet when the latter is running here.
 511          */
 512         tasklet = hv_context.event_dpc[channel->target_cpu];
 513         tasklet_disable(tasklet);
 514
 515         /*
 516          * In case a device driver's probe() fails (e.g.,
 517          * util_probe() -> vmbus_open() returns -ENOMEM) and the device is
 518          * rescinded later (e.g., we dynamically disble an Integrated Service
 519          * in Hyper-V Manager), the driver's remove() invokes vmbus_close():
 520          * here we should skip most of the below cleanup work.
 521          */
 522         if (channel->state != CHANNEL_OPENED_STATE) {
 523                 ret = -EINVAL;
 524                 goto out;
 525         }
 526
 527         channel->state = CHANNEL_OPEN_STATE;
 528         channel->sc_creation_callback = NULL;
 529         /* Stop callback and cancel the timer asap */
 530         if (channel->target_cpu != get_cpu()) {
 531                 put_cpu();
 532                 smp_call_function_single(channel->target_cpu, reset_channel_cb,
 533                                          channel, true);
 534         } else {
 535                 reset_channel_cb(channel);
 536                 put_cpu();
 537         }
 538
 539         /* Send a closing message */
 540
 541         msg = &channel->close_msg.msg;
 542
 543         msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
 544         msg->child_relid = channel->offermsg.child_relid;
 545
 546         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel));
 547
 548         if (ret) {
 549                 pr_err("Close failed: close post msg return is %d\n", ret);
 550                 /*
 551                  * If we failed to post the close msg,
 552                  * it is perhaps better to leak memory.
 553                  */
 554                 goto out;
 555         }
 556
 557         /* Tear down the gpadl for the channel's ring buffer */
 558         if (channel->ringbuffer_gpadlhandle) {
 559                 ret = vmbus_teardown_gpadl(channel,
 560                                            channel->ringbuffer_gpadlhandle);
 561                 if (ret) {
 562                         pr_err("Close failed: teardown gpadl return %d\n", ret);
 563                         /*
 564                          * If we failed to teardown gpadl,
 565                          * it is perhaps better to leak memory.
 566                          */
 567                         goto out;
 568                 }
 569         }
 570
 571         /* Cleanup the ring buffers for this channel */
 572         hv_ringbuffer_cleanup(&channel->outbound);
 573         hv_ringbuffer_cleanup(&channel->inbound);
 574
 575         free_pages((unsigned long)channel->ringbuffer_pages,
 576                 get_order(channel->ringbuffer_pagecount * PAGE_SIZE));
 577
 578 out:
 579         tasklet_enable(tasklet);
 580
 581         return ret;
 582 }
 583
 584 /*
 585  * vmbus_close - Close the specified channel
 586  */
 587 void vmbus_close(struct vmbus_channel *channel)
 588 {
 589         struct list_head *cur, *tmp;
 590         struct vmbus_channel *cur_channel;
 591
 592         if (channel->primary_channel != NULL) {
 593                 /*
 594                  * We will only close sub-channels when
 595                  * the primary is closed.
 596                  */
 597                 return;
 598         }
 599         /*
 600          * Close all the sub-channels first and then close the
 601          * primary channel.
 602          */
 603         list_for_each_safe(cur, tmp, &channel->sc_list) {
 604                 cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 605                 if (cur_channel->state != CHANNEL_OPENED_STATE)
 606                         continue;
 607                 vmbus_close_internal(cur_channel);
 608         }
 609         /*
 610          * Now close the primary.
 611          */
 612         vmbus_close_internal(channel);
 613 }
 614 EXPORT_SYMBOL_GPL(vmbus_close);
 615
 616 int vmbus_sendpacket_ctl(struct vmbus_channel *channel, void *buffer,
 617                            u32 bufferlen, u64 requestid,
 618                            enum vmbus_packet_type type, u32 flags, bool kick_q)
 619 {
 620         struct vmpacket_descriptor desc;
 621         u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
 622         u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 623         struct kvec bufferlist[3];
 624         u64 aligned_data = 0;
 625         int ret;
 626         bool signal = false;
 627         int num_vecs = ((bufferlen != 0) ? 3 : 1);
 628
 629
 630         /* Setup the descriptor */
 631         desc.type = type; /* VmbusPacketTypeDataInBand; */
 632         desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
 633         /* in 8-bytes granularity */
 634         desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3;
 635         desc.len8 = (u16)(packetlen_aligned >> 3);
 636         desc.trans_id = requestid;
 637
 638         bufferlist[0].iov_base = &desc;
 639         bufferlist[0].iov_len = sizeof(struct vmpacket_descriptor);
 640         bufferlist[1].iov_base = buffer;
 641         bufferlist[1].iov_len = bufferlen;
 642         bufferlist[2].iov_base = &aligned_data;
 643         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 644
 645         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, num_vecs,
 646                                   &signal);
 647
 648         /*
 649          * Signalling the host is conditional on many factors:
 650          * 1. The ring state changed from being empty to non-empty.
 651          *    This is tracked by the variable "signal".
 652          * 2. The variable kick_q tracks if more data will be placed
 653          *    on the ring. We will not signal if more data is
 654          *    to be placed.
 655          *
 656          * Based on the channel signal state, we will decide
 657          * which signaling policy will be applied.
 658          *
 659          * If we cannot write to the ring-buffer; signal the host
 660          * even if we may not have written anything. This is a rare
 661          * enough condition that it should not matter.
 662          */
 663
 664         if (channel->signal_policy)
 665                 signal = true;
 666         else
 667                 kick_q = true;
 668
 669         if (((ret == 0) && kick_q && signal) || (ret))
 670                 vmbus_setevent(channel);
 671
 672         return ret;
 673 }
 674 EXPORT_SYMBOL(vmbus_sendpacket_ctl);
 675
 676 /**
 677  * vmbus_sendpacket() - Send the specified buffer on the given channel
 678  * @channel: Pointer to vmbus_channel structure.
 679  * @buffer: Pointer to the buffer you want to receive the data into.
 680  * @bufferlen: Maximum size of what the the buffer will hold
 681  * @requestid: Identifier of the request
 682  * @type: Type of packet that is being send e.g. negotiate, time
 683  * packet etc.
 684  *
 685  * Sends data in @buffer directly to hyper-v via the vmbus
 686  * This will send the data unparsed to hyper-v.
 687  *
 688  * Mainly used by Hyper-V drivers.
 689  */
 690 int vmbus_sendpacket(struct vmbus_channel *channel, void *buffer,
 691                            u32 bufferlen, u64 requestid,
 692                            enum vmbus_packet_type type, u32 flags)
 693 {
 694         return vmbus_sendpacket_ctl(channel, buffer, bufferlen, requestid,
 695                                     type, flags, true);
 696 }
 697 EXPORT_SYMBOL(vmbus_sendpacket);
 698
 699 /*
 700  * vmbus_sendpacket_pagebuffer_ctl - Send a range of single-page buffer
 701  * packets using a GPADL Direct packet type. This interface allows you
 702  * to control notifying the host. This will be useful for sending
 703  * batched data. Also the sender can control the send flags
 704  * explicitly.
 705  */
 706 int vmbus_sendpacket_pagebuffer_ctl(struct vmbus_channel *channel,
 707                                      struct hv_page_buffer pagebuffers[],
 708                                      u32 pagecount, void *buffer, u32 bufferlen,
 709                                      u64 requestid,
 710                                      u32 flags,
 711                                      bool kick_q)
 712 {
 713         int ret;
 714         int i;
 715         struct vmbus_channel_packet_page_buffer desc;
 716         u32 descsize;
 717         u32 packetlen;
 718         u32 packetlen_aligned;
 719         struct kvec bufferlist[3];
 720         u64 aligned_data = 0;
 721         bool signal = false;
 722
 723         if (pagecount > MAX_PAGE_BUFFER_COUNT)
 724                 return -EINVAL;
 725
 726
 727         /*
 728          * Adjust the size down since vmbus_channel_packet_page_buffer is the
 729          * largest size we support
 730          */
 731         descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
 732                           ((MAX_PAGE_BUFFER_COUNT - pagecount) *
 733                           sizeof(struct hv_page_buffer));
 734         packetlen = descsize + bufferlen;
 735         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 736
 737         /* Setup the descriptor */
 738         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
 739         desc.flags = flags;
 740         desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
 741         desc.length8 = (u16)(packetlen_aligned >> 3);
 742         desc.transactionid = requestid;
 743         desc.rangecount = pagecount;
 744
 745         for (i = 0; i < pagecount; i++) {
 746                 desc.range[i].len = pagebuffers[i].len;
 747                 desc.range[i].offset = pagebuffers[i].offset;
 748                 desc.range[i].pfn        = pagebuffers[i].pfn;
 749         }
 750
 751         bufferlist[0].iov_base = &desc;
 752         bufferlist[0].iov_len = descsize;
 753         bufferlist[1].iov_base = buffer;
 754         bufferlist[1].iov_len = bufferlen;
 755         bufferlist[2].iov_base = &aligned_data;
 756         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 757
 758         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
 759
 760         /*
 761          * Signalling the host is conditional on many factors:
 762          * 1. The ring state changed from being empty to non-empty.
 763          *    This is tracked by the variable "signal".
 764          * 2. The variable kick_q tracks if more data will be placed
 765          *    on the ring. We will not signal if more data is
 766          *    to be placed.
 767          *
 768          * Based on the channel signal state, we will decide
 769          * which signaling policy will be applied.
 770          *
 771          * If we cannot write to the ring-buffer; signal the host
 772          * even if we may not have written anything. This is a rare
 773          * enough condition that it should not matter.
 774          */
 775
 776         if (channel->signal_policy)
 777                 signal = true;
 778         else
 779                 kick_q = true;
 780
 781         if (((ret == 0) && kick_q && signal) || (ret))
 782                 vmbus_setevent(channel);
 783
 784         return ret;
 785 }
 786 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer_ctl);
 787
 788 /*
 789  * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
 790  * packets using a GPADL Direct packet type.
 791  */
 792 int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
 793                                      struct hv_page_buffer pagebuffers[],
 794                                      u32 pagecount, void *buffer, u32 bufferlen,
 795                                      u64 requestid)
 796 {
 797         u32 flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 798         return vmbus_sendpacket_pagebuffer_ctl(channel, pagebuffers, pagecount,
 799                                                buffer, bufferlen, requestid,
 800                                                flags, true);
 801
 802 }
 803 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
 804
 805 /*
 806  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
 807  * using a GPADL Direct packet type.
 808  * The buffer includes the vmbus descriptor.
 809  */
 810 int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
 811                               struct vmbus_packet_mpb_array *desc,
 812                               u32 desc_size,
 813                               void *buffer, u32 bufferlen, u64 requestid)
 814 {
 815         int ret;
 816         u32 packetlen;
 817         u32 packetlen_aligned;
 818         struct kvec bufferlist[3];
 819         u64 aligned_data = 0;
 820         bool signal = false;
 821
 822         packetlen = desc_size + bufferlen;
 823         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 824
 825         /* Setup the descriptor */
 826         desc->type = VM_PKT_DATA_USING_GPA_DIRECT;
 827         desc->flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 828         desc->dataoffset8 = desc_size >> 3; /* in 8-bytes grandularity */
 829         desc->length8 = (u16)(packetlen_aligned >> 3);
 830         desc->transactionid = requestid;
 831         desc->rangecount = 1;
 832
 833         bufferlist[0].iov_base = desc;
 834         bufferlist[0].iov_len = desc_size;
 835         bufferlist[1].iov_base = buffer;
 836         bufferlist[1].iov_len = bufferlen;
 837         bufferlist[2].iov_base = &aligned_data;
 838         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 839
 840         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
 841
 842         if (ret == 0 && signal)
 843                 vmbus_setevent(channel);
 844
 845         return ret;
 846 }
 847 EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc);
 848
 849 /*
 850  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
 851  * using a GPADL Direct packet type.
 852  */
 853 int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
 854                                 struct hv_multipage_buffer *multi_pagebuffer,
 855                                 void *buffer, u32 bufferlen, u64 requestid)
 856 {
 857         int ret;
 858         struct vmbus_channel_packet_multipage_buffer desc;
 859         u32 descsize;
 860         u32 packetlen;
 861         u32 packetlen_aligned;
 862         struct kvec bufferlist[3];
 863         u64 aligned_data = 0;
 864         bool signal = false;
 865         u32 pfncount = NUM_PAGES_SPANNED(multi_pagebuffer->offset,
 866                                          multi_pagebuffer->len);
 867
 868         if (pfncount > MAX_MULTIPAGE_BUFFER_COUNT)
 869                 return -EINVAL;
 870
 871         /*
 872          * Adjust the size down since vmbus_channel_packet_multipage_buffer is
 873          * the largest size we support
 874          */
 875         descsize = sizeof(struct vmbus_channel_packet_multipage_buffer) -
 876                           ((MAX_MULTIPAGE_BUFFER_COUNT - pfncount) *
 877                           sizeof(u64));
 878         packetlen = descsize + bufferlen;
 879         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 880
 881
 882         /* Setup the descriptor */
 883         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
 884         desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 885         desc.dataoffset8 = descsize >> 3; /* in 8-bytes grandularity */
 886         desc.length8 = (u16)(packetlen_aligned >> 3);
 887         desc.transactionid = requestid;
 888         desc.rangecount = 1;
 889
 890         desc.range.len = multi_pagebuffer->len;
 891         desc.range.offset = multi_pagebuffer->offset;
 892
 893         memcpy(desc.range.pfn_array, multi_pagebuffer->pfn_array,
 894                pfncount * sizeof(u64));
 895
 896         bufferlist[0].iov_base = &desc;
 897         bufferlist[0].iov_len = descsize;
 898         bufferlist[1].iov_base = buffer;
 899         bufferlist[1].iov_len = bufferlen;
 900         bufferlist[2].iov_base = &aligned_data;
 901         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 902
 903         ret = hv_ringbuffer_write(&channel->outbound, bufferlist, 3, &signal);
 904
 905         if (ret == 0 && signal)
 906                 vmbus_setevent(channel);
 907
 908         return ret;
 909 }
 910 EXPORT_SYMBOL_GPL(vmbus_sendpacket_multipagebuffer);
 911
 912 /**
 913  * vmbus_recvpacket() - Retrieve the user packet on the specified channel
 914  * @channel: Pointer to vmbus_channel structure.
 915  * @buffer: Pointer to the buffer you want to receive the data into.
 916  * @bufferlen: Maximum size of what the the buffer will hold
 917  * @buffer_actual_len: The actual size of the data after it was received
 918  * @requestid: Identifier of the request
 919  *
 920  * Receives directly from the hyper-v vmbus and puts the data it received
 921  * into Buffer. This will receive the data unparsed from hyper-v.
 922  *
 923  * Mainly used by Hyper-V drivers.
 924  */
 925 static inline int
 926 __vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
 927                    u32 bufferlen, u32 *buffer_actual_len, u64 *requestid,
 928                    bool raw)
 929 {
 930         int ret;
 931         bool signal = false;
 932
 933         ret = hv_ringbuffer_read(&channel->inbound, buffer, bufferlen,
 934                                  buffer_actual_len, requestid, &signal, raw);
 935
 936         if (signal)
 937                 vmbus_setevent(channel);
 938
 939         return ret;
 940 }
 941
 942 int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
 943                      u32 bufferlen, u32 *buffer_actual_len,
 944                      u64 *requestid)
 945 {
 946         return __vmbus_recvpacket(channel, buffer, bufferlen,
 947                                   buffer_actual_len, requestid, false);
 948 }
 949 EXPORT_SYMBOL(vmbus_recvpacket);
 950
 951 /*
 952  * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
 953  */
 954 int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
 955                               u32 bufferlen, u32 *buffer_actual_len,
 956                               u64 *requestid)
 957 {
 958         return __vmbus_recvpacket(channel, buffer, bufferlen,
 959                                   buffer_actual_len, requestid, true);
 960 }
 961 EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);