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