drivers/hv/channel.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2009, Microsoft Corporation.
   4  *
   5  * Authors:
   6  *   Haiyang Zhang <[email protected]>
   7  *   Hank Janssen  <[email protected]>
   8  */
   9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11 #include <linux/kernel.h>
  12 #include <linux/sched.h>
  13 #include <linux/wait.h>
  14 #include <linux/mm.h>
  15 #include <linux/slab.h>
  16 #include <linux/module.h>
  17 #include <linux/hyperv.h>
  18 #include <linux/uio.h>
  19 #include <linux/interrupt.h>
  20 #include <asm/page.h>
  21
  22 #include "hyperv_vmbus.h"
  23
  24 #define NUM_PAGES_SPANNED(addr, len) \
  25 ((PAGE_ALIGN(addr + len) >> PAGE_SHIFT) - (addr >> PAGE_SHIFT))
  26
  27 static unsigned long virt_to_hvpfn(void *addr)
  28 {
  29         phys_addr_t paddr;
  30
  31         if (is_vmalloc_addr(addr))
  32                 paddr = page_to_phys(vmalloc_to_page(addr)) +
  33                                          offset_in_page(addr);
  34         else
  35                 paddr = __pa(addr);
  36
  37         return  paddr >> PAGE_SHIFT;
  38 }
  39
  40 /*
  41  * vmbus_setevent- Trigger an event notification on the specified
  42  * channel.
  43  */
  44 void vmbus_setevent(struct vmbus_channel *channel)
  45 {
  46         struct hv_monitor_page *monitorpage;
  47
  48         trace_vmbus_setevent(channel);
  49
  50         /*
  51          * For channels marked as in "low latency" mode
  52          * bypass the monitor page mechanism.
  53          */
  54         if (channel->offermsg.monitor_allocated && !channel->low_latency) {
  55                 vmbus_send_interrupt(channel->offermsg.child_relid);
  56
  57                 /* Get the child to parent monitor page */
  58                 monitorpage = vmbus_connection.monitor_pages[1];
  59
  60                 sync_set_bit(channel->monitor_bit,
  61                         (unsigned long *)&monitorpage->trigger_group
  62                                         [channel->monitor_grp].pending);
  63
  64         } else {
  65                 vmbus_set_event(channel);
  66         }
  67 }
  68 EXPORT_SYMBOL_GPL(vmbus_setevent);
  69
  70 /* vmbus_free_ring - drop mapping of ring buffer */
  71 void vmbus_free_ring(struct vmbus_channel *channel)
  72 {
  73         hv_ringbuffer_cleanup(&channel->outbound);
  74         hv_ringbuffer_cleanup(&channel->inbound);
  75
  76         if (channel->ringbuffer_page) {
  77                 __free_pages(channel->ringbuffer_page,
  78                              get_order(channel->ringbuffer_pagecount
  79                                        << PAGE_SHIFT));
  80                 channel->ringbuffer_page = NULL;
  81         }
  82 }
  83 EXPORT_SYMBOL_GPL(vmbus_free_ring);
  84
  85 /* vmbus_alloc_ring - allocate and map pages for ring buffer */
  86 int vmbus_alloc_ring(struct vmbus_channel *newchannel,
  87                      u32 send_size, u32 recv_size)
  88 {
  89         struct page *page;
  90         int order;
  91
  92         if (send_size % PAGE_SIZE || recv_size % PAGE_SIZE)
  93                 return -EINVAL;
  94
  95         /* Allocate the ring buffer */
  96         order = get_order(send_size + recv_size);
  97         page = alloc_pages_node(cpu_to_node(newchannel->target_cpu),
  98                                 GFP_KERNEL|__GFP_ZERO, order);
  99
 100         if (!page)
 101                 page = alloc_pages(GFP_KERNEL|__GFP_ZERO, order);
 102
 103         if (!page)
 104                 return -ENOMEM;
 105
 106         newchannel->ringbuffer_page = page;
 107         newchannel->ringbuffer_pagecount = (send_size + recv_size) >> PAGE_SHIFT;
 108         newchannel->ringbuffer_send_offset = send_size >> PAGE_SHIFT;
 109
 110         return 0;
 111 }
 112 EXPORT_SYMBOL_GPL(vmbus_alloc_ring);
 113
 114 static int __vmbus_open(struct vmbus_channel *newchannel,
 115                        void *userdata, u32 userdatalen,
 116                        void (*onchannelcallback)(void *context), void *context)
 117 {
 118         struct vmbus_channel_open_channel *open_msg;
 119         struct vmbus_channel_msginfo *open_info = NULL;
 120         struct page *page = newchannel->ringbuffer_page;
 121         u32 send_pages, recv_pages;
 122         unsigned long flags;
 123         int err;
 124
 125         if (userdatalen > MAX_USER_DEFINED_BYTES)
 126                 return -EINVAL;
 127
 128         send_pages = newchannel->ringbuffer_send_offset;
 129         recv_pages = newchannel->ringbuffer_pagecount - send_pages;
 130
 131         spin_lock_irqsave(&newchannel->lock, flags);
 132         if (newchannel->state != CHANNEL_OPEN_STATE) {
 133                 spin_unlock_irqrestore(&newchannel->lock, flags);
 134                 return -EINVAL;
 135         }
 136         spin_unlock_irqrestore(&newchannel->lock, flags);
 137
 138         newchannel->state = CHANNEL_OPENING_STATE;
 139         newchannel->onchannel_callback = onchannelcallback;
 140         newchannel->channel_callback_context = context;
 141
 142         err = hv_ringbuffer_init(&newchannel->outbound, page, send_pages);
 143         if (err)
 144                 goto error_clean_ring;
 145
 146         err = hv_ringbuffer_init(&newchannel->inbound,
 147                                  &page[send_pages], recv_pages);
 148         if (err)
 149                 goto error_clean_ring;
 150
 151         /* Establish the gpadl for the ring buffer */
 152         newchannel->ringbuffer_gpadlhandle = 0;
 153
 154         err = vmbus_establish_gpadl(newchannel,
 155                                     page_address(newchannel->ringbuffer_page),
 156                                     (send_pages + recv_pages) << PAGE_SHIFT,
 157                                     &newchannel->ringbuffer_gpadlhandle);
 158         if (err)
 159                 goto error_clean_ring;
 160
 161         /* Create and init the channel open message */
 162         open_info = kmalloc(sizeof(*open_info) +
 163                            sizeof(struct vmbus_channel_open_channel),
 164                            GFP_KERNEL);
 165         if (!open_info) {
 166                 err = -ENOMEM;
 167                 goto error_free_gpadl;
 168         }
 169
 170         init_completion(&open_info->waitevent);
 171         open_info->waiting_channel = newchannel;
 172
 173         open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
 174         open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
 175         open_msg->openid = newchannel->offermsg.child_relid;
 176         open_msg->child_relid = newchannel->offermsg.child_relid;
 177         open_msg->ringbuffer_gpadlhandle = newchannel->ringbuffer_gpadlhandle;
 178         open_msg->downstream_ringbuffer_pageoffset = newchannel->ringbuffer_send_offset;
 179         open_msg->target_vp = newchannel->target_vp;
 180
 181         if (userdatalen)
 182                 memcpy(open_msg->userdata, userdata, userdatalen);
 183
 184         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 185         list_add_tail(&open_info->msglistentry,
 186                       &vmbus_connection.chn_msg_list);
 187         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 188
 189         if (newchannel->rescind) {
 190                 err = -ENODEV;
 191                 goto error_free_info;
 192         }
 193
 194         err = vmbus_post_msg(open_msg,
 195                              sizeof(struct vmbus_channel_open_channel), true);
 196
 197         trace_vmbus_open(open_msg, err);
 198
 199         if (err != 0)
 200                 goto error_clean_msglist;
 201
 202         wait_for_completion(&open_info->waitevent);
 203
 204         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 205         list_del(&open_info->msglistentry);
 206         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 207
 208         if (newchannel->rescind) {
 209                 err = -ENODEV;
 210                 goto error_free_info;
 211         }
 212
 213         if (open_info->response.open_result.status) {
 214                 err = -EAGAIN;
 215                 goto error_free_info;
 216         }
 217
 218         newchannel->state = CHANNEL_OPENED_STATE;
 219         kfree(open_info);
 220         return 0;
 221
 222 error_clean_msglist:
 223         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 224         list_del(&open_info->msglistentry);
 225         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 226 error_free_info:
 227         kfree(open_info);
 228 error_free_gpadl:
 229         vmbus_teardown_gpadl(newchannel, newchannel->ringbuffer_gpadlhandle);
 230         newchannel->ringbuffer_gpadlhandle = 0;
 231 error_clean_ring:
 232         hv_ringbuffer_cleanup(&newchannel->outbound);
 233         hv_ringbuffer_cleanup(&newchannel->inbound);
 234         newchannel->state = CHANNEL_OPEN_STATE;
 235         return err;
 236 }
 237
 238 /*
 239  * vmbus_connect_ring - Open the channel but reuse ring buffer
 240  */
 241 int vmbus_connect_ring(struct vmbus_channel *newchannel,
 242                        void (*onchannelcallback)(void *context), void *context)
 243 {
 244         return  __vmbus_open(newchannel, NULL, 0, onchannelcallback, context);
 245 }
 246 EXPORT_SYMBOL_GPL(vmbus_connect_ring);
 247
 248 /*
 249  * vmbus_open - Open the specified channel.
 250  */
 251 int vmbus_open(struct vmbus_channel *newchannel,
 252                u32 send_ringbuffer_size, u32 recv_ringbuffer_size,
 253                void *userdata, u32 userdatalen,
 254                void (*onchannelcallback)(void *context), void *context)
 255 {
 256         int err;
 257
 258         err = vmbus_alloc_ring(newchannel, send_ringbuffer_size,
 259                                recv_ringbuffer_size);
 260         if (err)
 261                 return err;
 262
 263         err = __vmbus_open(newchannel, userdata, userdatalen,
 264                            onchannelcallback, context);
 265         if (err)
 266                 vmbus_free_ring(newchannel);
 267
 268         return err;
 269 }
 270 EXPORT_SYMBOL_GPL(vmbus_open);
 271
 272 /* Used for Hyper-V Socket: a guest client's connect() to the host */
 273 int vmbus_send_tl_connect_request(const guid_t *shv_guest_servie_id,
 274                                   const guid_t *shv_host_servie_id)
 275 {
 276         struct vmbus_channel_tl_connect_request conn_msg;
 277         int ret;
 278
 279         memset(&conn_msg, 0, sizeof(conn_msg));
 280         conn_msg.header.msgtype = CHANNELMSG_TL_CONNECT_REQUEST;
 281         conn_msg.guest_endpoint_id = *shv_guest_servie_id;
 282         conn_msg.host_service_id = *shv_host_servie_id;
 283
 284         ret = vmbus_post_msg(&conn_msg, sizeof(conn_msg), true);
 285
 286         trace_vmbus_send_tl_connect_request(&conn_msg, ret);
 287
 288         return ret;
 289 }
 290 EXPORT_SYMBOL_GPL(vmbus_send_tl_connect_request);
 291
 292 /*
 293  * Set/change the vCPU (@target_vp) the channel (@child_relid) will interrupt.
 294  *
 295  * CHANNELMSG_MODIFYCHANNEL messages are aynchronous.  Also, Hyper-V does not
 296  * ACK such messages.  IOW we can't know when the host will stop interrupting
 297  * the "old" vCPU and start interrupting the "new" vCPU for the given channel.
 298  *
 299  * The CHANNELMSG_MODIFYCHANNEL message type is supported since VMBus version
 300  * VERSION_WIN10_V4_1.
 301  */
 302 int vmbus_send_modifychannel(u32 child_relid, u32 target_vp)
 303 {
 304         struct vmbus_channel_modifychannel conn_msg;
 305         int ret;
 306
 307         memset(&conn_msg, 0, sizeof(conn_msg));
 308         conn_msg.header.msgtype = CHANNELMSG_MODIFYCHANNEL;
 309         conn_msg.child_relid = child_relid;
 310         conn_msg.target_vp = target_vp;
 311
 312         ret = vmbus_post_msg(&conn_msg, sizeof(conn_msg), true);
 313
 314         trace_vmbus_send_modifychannel(&conn_msg, ret);
 315
 316         return ret;
 317 }
 318 EXPORT_SYMBOL_GPL(vmbus_send_modifychannel);
 319
 320 /*
 321  * create_gpadl_header - Creates a gpadl for the specified buffer
 322  */
 323 static int create_gpadl_header(void *kbuffer, u32 size,
 324                                struct vmbus_channel_msginfo **msginfo)
 325 {
 326         int i;
 327         int pagecount;
 328         struct vmbus_channel_gpadl_header *gpadl_header;
 329         struct vmbus_channel_gpadl_body *gpadl_body;
 330         struct vmbus_channel_msginfo *msgheader;
 331         struct vmbus_channel_msginfo *msgbody = NULL;
 332         u32 msgsize;
 333
 334         int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
 335
 336         pagecount = size >> PAGE_SHIFT;
 337
 338         /* do we need a gpadl body msg */
 339         pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 340                   sizeof(struct vmbus_channel_gpadl_header) -
 341                   sizeof(struct gpa_range);
 342         pfncount = pfnsize / sizeof(u64);
 343
 344         if (pagecount > pfncount) {
 345                 /* we need a gpadl body */
 346                 /* fill in the header */
 347                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 348                           sizeof(struct vmbus_channel_gpadl_header) +
 349                           sizeof(struct gpa_range) + pfncount * sizeof(u64);
 350                 msgheader =  kzalloc(msgsize, GFP_KERNEL);
 351                 if (!msgheader)
 352                         goto nomem;
 353
 354                 INIT_LIST_HEAD(&msgheader->submsglist);
 355                 msgheader->msgsize = msgsize;
 356
 357                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 358                         msgheader->msg;
 359                 gpadl_header->rangecount = 1;
 360                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 361                                          pagecount * sizeof(u64);
 362                 gpadl_header->range[0].byte_offset = 0;
 363                 gpadl_header->range[0].byte_count = size;
 364                 for (i = 0; i < pfncount; i++)
 365                         gpadl_header->range[0].pfn_array[i] = virt_to_hvpfn(
 366                                 kbuffer + PAGE_SIZE * i);
 367                 *msginfo = msgheader;
 368
 369                 pfnsum = pfncount;
 370                 pfnleft = pagecount - pfncount;
 371
 372                 /* how many pfns can we fit */
 373                 pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 374                           sizeof(struct vmbus_channel_gpadl_body);
 375                 pfncount = pfnsize / sizeof(u64);
 376
 377                 /* fill in the body */
 378                 while (pfnleft) {
 379                         if (pfnleft > pfncount)
 380                                 pfncurr = pfncount;
 381                         else
 382                                 pfncurr = pfnleft;
 383
 384                         msgsize = sizeof(struct vmbus_channel_msginfo) +
 385                                   sizeof(struct vmbus_channel_gpadl_body) +
 386                                   pfncurr * sizeof(u64);
 387                         msgbody = kzalloc(msgsize, GFP_KERNEL);
 388
 389                         if (!msgbody) {
 390                                 struct vmbus_channel_msginfo *pos = NULL;
 391                                 struct vmbus_channel_msginfo *tmp = NULL;
 392                                 /*
 393                                  * Free up all the allocated messages.
 394                                  */
 395                                 list_for_each_entry_safe(pos, tmp,
 396                                         &msgheader->submsglist,
 397                                         msglistentry) {
 398
 399                                         list_del(&pos->msglistentry);
 400                                         kfree(pos);
 401                                 }
 402
 403                                 goto nomem;
 404                         }
 405
 406                         msgbody->msgsize = msgsize;
 407                         gpadl_body =
 408                                 (struct vmbus_channel_gpadl_body *)msgbody->msg;
 409
 410                         /*
 411                          * Gpadl is u32 and we are using a pointer which could
 412                          * be 64-bit
 413                          * This is governed by the guest/host protocol and
 414                          * so the hypervisor guarantees that this is ok.
 415                          */
 416                         for (i = 0; i < pfncurr; i++)
 417                                 gpadl_body->pfn[i] = virt_to_hvpfn(
 418                                         kbuffer + PAGE_SIZE * (pfnsum + i));
 419
 420                         /* add to msg header */
 421                         list_add_tail(&msgbody->msglistentry,
 422                                       &msgheader->submsglist);
 423                         pfnsum += pfncurr;
 424                         pfnleft -= pfncurr;
 425                 }
 426         } else {
 427                 /* everything fits in a header */
 428                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 429                           sizeof(struct vmbus_channel_gpadl_header) +
 430                           sizeof(struct gpa_range) + pagecount * sizeof(u64);
 431                 msgheader = kzalloc(msgsize, GFP_KERNEL);
 432                 if (msgheader == NULL)
 433                         goto nomem;
 434
 435                 INIT_LIST_HEAD(&msgheader->submsglist);
 436                 msgheader->msgsize = msgsize;
 437
 438                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 439                         msgheader->msg;
 440                 gpadl_header->rangecount = 1;
 441                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 442                                          pagecount * sizeof(u64);
 443                 gpadl_header->range[0].byte_offset = 0;
 444                 gpadl_header->range[0].byte_count = size;
 445                 for (i = 0; i < pagecount; i++)
 446                         gpadl_header->range[0].pfn_array[i] = virt_to_hvpfn(
 447                                 kbuffer + PAGE_SIZE * i);
 448
 449                 *msginfo = msgheader;
 450         }
 451
 452         return 0;
 453 nomem:
 454         kfree(msgheader);
 455         kfree(msgbody);
 456         return -ENOMEM;
 457 }
 458
 459 /*
 460  * vmbus_establish_gpadl - Establish a GPADL for the specified buffer
 461  *
 462  * @channel: a channel
 463  * @kbuffer: from kmalloc or vmalloc
 464  * @size: page-size multiple
 465  * @gpadl_handle: some funky thing
 466  */
 467 int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
 468                                u32 size, u32 *gpadl_handle)
 469 {
 470         struct vmbus_channel_gpadl_header *gpadlmsg;
 471         struct vmbus_channel_gpadl_body *gpadl_body;
 472         struct vmbus_channel_msginfo *msginfo = NULL;
 473         struct vmbus_channel_msginfo *submsginfo, *tmp;
 474         struct list_head *curr;
 475         u32 next_gpadl_handle;
 476         unsigned long flags;
 477         int ret = 0;
 478
 479         next_gpadl_handle =
 480                 (atomic_inc_return(&vmbus_connection.next_gpadl_handle) - 1);
 481
 482         ret = create_gpadl_header(kbuffer, size, &msginfo);
 483         if (ret)
 484                 return ret;
 485
 486         init_completion(&msginfo->waitevent);
 487         msginfo->waiting_channel = channel;
 488
 489         gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
 490         gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
 491         gpadlmsg->child_relid = channel->offermsg.child_relid;
 492         gpadlmsg->gpadl = next_gpadl_handle;
 493
 494
 495         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 496         list_add_tail(&msginfo->msglistentry,
 497                       &vmbus_connection.chn_msg_list);
 498
 499         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 500
 501         if (channel->rescind) {
 502                 ret = -ENODEV;
 503                 goto cleanup;
 504         }
 505
 506         ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize -
 507                              sizeof(*msginfo), true);
 508
 509         trace_vmbus_establish_gpadl_header(gpadlmsg, ret);
 510
 511         if (ret != 0)
 512                 goto cleanup;
 513
 514         list_for_each(curr, &msginfo->submsglist) {
 515                 submsginfo = (struct vmbus_channel_msginfo *)curr;
 516                 gpadl_body =
 517                         (struct vmbus_channel_gpadl_body *)submsginfo->msg;
 518
 519                 gpadl_body->header.msgtype =
 520                         CHANNELMSG_GPADL_BODY;
 521                 gpadl_body->gpadl = next_gpadl_handle;
 522
 523                 ret = vmbus_post_msg(gpadl_body,
 524                                      submsginfo->msgsize - sizeof(*submsginfo),
 525                                      true);
 526
 527                 trace_vmbus_establish_gpadl_body(gpadl_body, ret);
 528
 529                 if (ret != 0)
 530                         goto cleanup;
 531
 532         }
 533         wait_for_completion(&msginfo->waitevent);
 534
 535         if (msginfo->response.gpadl_created.creation_status != 0) {
 536                 pr_err("Failed to establish GPADL: err = 0x%x\n",
 537                        msginfo->response.gpadl_created.creation_status);
 538
 539                 ret = -EDQUOT;
 540                 goto cleanup;
 541         }
 542
 543         if (channel->rescind) {
 544                 ret = -ENODEV;
 545                 goto cleanup;
 546         }
 547
 548         /* At this point, we received the gpadl created msg */
 549         *gpadl_handle = gpadlmsg->gpadl;
 550
 551 cleanup:
 552         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 553         list_del(&msginfo->msglistentry);
 554         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 555         list_for_each_entry_safe(submsginfo, tmp, &msginfo->submsglist,
 556                                  msglistentry) {
 557                 kfree(submsginfo);
 558         }
 559
 560         kfree(msginfo);
 561         return ret;
 562 }
 563 EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
 564
 565 /*
 566  * vmbus_teardown_gpadl -Teardown the specified GPADL handle
 567  */
 568 int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
 569 {
 570         struct vmbus_channel_gpadl_teardown *msg;
 571         struct vmbus_channel_msginfo *info;
 572         unsigned long flags;
 573         int ret;
 574
 575         info = kmalloc(sizeof(*info) +
 576                        sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
 577         if (!info)
 578                 return -ENOMEM;
 579
 580         init_completion(&info->waitevent);
 581         info->waiting_channel = channel;
 582
 583         msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
 584
 585         msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
 586         msg->child_relid = channel->offermsg.child_relid;
 587         msg->gpadl = gpadl_handle;
 588
 589         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 590         list_add_tail(&info->msglistentry,
 591                       &vmbus_connection.chn_msg_list);
 592         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 593
 594         if (channel->rescind)
 595                 goto post_msg_err;
 596
 597         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_gpadl_teardown),
 598                              true);
 599
 600         trace_vmbus_teardown_gpadl(msg, ret);
 601
 602         if (ret)
 603                 goto post_msg_err;
 604
 605         wait_for_completion(&info->waitevent);
 606
 607 post_msg_err:
 608         /*
 609          * If the channel has been rescinded;
 610          * we will be awakened by the rescind
 611          * handler; set the error code to zero so we don't leak memory.
 612          */
 613         if (channel->rescind)
 614                 ret = 0;
 615
 616         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 617         list_del(&info->msglistentry);
 618         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 619
 620         kfree(info);
 621         return ret;
 622 }
 623 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
 624
 625 void vmbus_reset_channel_cb(struct vmbus_channel *channel)
 626 {
 627         unsigned long flags;
 628
 629         /*
 630          * vmbus_on_event(), running in the per-channel tasklet, can race
 631          * with vmbus_close_internal() in the case of SMP guest, e.g., when
 632          * the former is accessing channel->inbound.ring_buffer, the latter
 633          * could be freeing the ring_buffer pages, so here we must stop it
 634          * first.
 635          *
 636          * vmbus_chan_sched() might call the netvsc driver callback function
 637          * that ends up scheduling NAPI work that accesses the ring buffer.
 638          * At this point, we have to ensure that any such work is completed
 639          * and that the channel ring buffer is no longer being accessed, cf.
 640          * the calls to napi_disable() in netvsc_device_remove().
 641          */
 642         tasklet_disable(&channel->callback_event);
 643
 644         /* See the inline comments in vmbus_chan_sched(). */
 645         spin_lock_irqsave(&channel->sched_lock, flags);
 646         channel->onchannel_callback = NULL;
 647         spin_unlock_irqrestore(&channel->sched_lock, flags);
 648
 649         channel->sc_creation_callback = NULL;
 650
 651         /* Re-enable tasklet for use on re-open */
 652         tasklet_enable(&channel->callback_event);
 653 }
 654
 655 static int vmbus_close_internal(struct vmbus_channel *channel)
 656 {
 657         struct vmbus_channel_close_channel *msg;
 658         int ret;
 659
 660         vmbus_reset_channel_cb(channel);
 661
 662         /*
 663          * In case a device driver's probe() fails (e.g.,
 664          * util_probe() -> vmbus_open() returns -ENOMEM) and the device is
 665          * rescinded later (e.g., we dynamically disable an Integrated Service
 666          * in Hyper-V Manager), the driver's remove() invokes vmbus_close():
 667          * here we should skip most of the below cleanup work.
 668          */
 669         if (channel->state != CHANNEL_OPENED_STATE)
 670                 return -EINVAL;
 671
 672         channel->state = CHANNEL_OPEN_STATE;
 673
 674         /* Send a closing message */
 675
 676         msg = &channel->close_msg.msg;
 677
 678         msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
 679         msg->child_relid = channel->offermsg.child_relid;
 680
 681         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel),
 682                              true);
 683
 684         trace_vmbus_close_internal(msg, ret);
 685
 686         if (ret) {
 687                 pr_err("Close failed: close post msg return is %d\n", ret);
 688                 /*
 689                  * If we failed to post the close msg,
 690                  * it is perhaps better to leak memory.
 691                  */
 692         }
 693
 694         /* Tear down the gpadl for the channel's ring buffer */
 695         else if (channel->ringbuffer_gpadlhandle) {
 696                 ret = vmbus_teardown_gpadl(channel,
 697                                            channel->ringbuffer_gpadlhandle);
 698                 if (ret) {
 699                         pr_err("Close failed: teardown gpadl return %d\n", ret);
 700                         /*
 701                          * If we failed to teardown gpadl,
 702                          * it is perhaps better to leak memory.
 703                          */
 704                 }
 705
 706                 channel->ringbuffer_gpadlhandle = 0;
 707         }
 708
 709         return ret;
 710 }
 711
 712 /* disconnect ring - close all channels */
 713 int vmbus_disconnect_ring(struct vmbus_channel *channel)
 714 {
 715         struct vmbus_channel *cur_channel, *tmp;
 716         int ret;
 717
 718         if (channel->primary_channel != NULL)
 719                 return -EINVAL;
 720
 721         list_for_each_entry_safe(cur_channel, tmp, &channel->sc_list, sc_list) {
 722                 if (cur_channel->rescind)
 723                         wait_for_completion(&cur_channel->rescind_event);
 724
 725                 mutex_lock(&vmbus_connection.channel_mutex);
 726                 if (vmbus_close_internal(cur_channel) == 0) {
 727                         vmbus_free_ring(cur_channel);
 728
 729                         if (cur_channel->rescind)
 730                                 hv_process_channel_removal(cur_channel);
 731                 }
 732                 mutex_unlock(&vmbus_connection.channel_mutex);
 733         }
 734
 735         /*
 736          * Now close the primary.
 737          */
 738         mutex_lock(&vmbus_connection.channel_mutex);
 739         ret = vmbus_close_internal(channel);
 740         mutex_unlock(&vmbus_connection.channel_mutex);
 741
 742         return ret;
 743 }
 744 EXPORT_SYMBOL_GPL(vmbus_disconnect_ring);
 745
 746 /*
 747  * vmbus_close - Close the specified channel
 748  */
 749 void vmbus_close(struct vmbus_channel *channel)
 750 {
 751         if (vmbus_disconnect_ring(channel) == 0)
 752                 vmbus_free_ring(channel);
 753 }
 754 EXPORT_SYMBOL_GPL(vmbus_close);
 755
 756 /**
 757  * vmbus_sendpacket() - Send the specified buffer on the given channel
 758  * @channel: Pointer to vmbus_channel structure
 759  * @buffer: Pointer to the buffer you want to send the data from.
 760  * @bufferlen: Maximum size of what the buffer holds.
 761  * @requestid: Identifier of the request
 762  * @type: Type of packet that is being sent e.g. negotiate, time
 763  *        packet etc.
 764  * @flags: 0 or VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED
 765  *
 766  * Sends data in @buffer directly to Hyper-V via the vmbus.
 767  * This will send the data unparsed to Hyper-V.
 768  *
 769  * Mainly used by Hyper-V drivers.
 770  */
 771 int vmbus_sendpacket(struct vmbus_channel *channel, void *buffer,
 772                            u32 bufferlen, u64 requestid,
 773                            enum vmbus_packet_type type, u32 flags)
 774 {
 775         struct vmpacket_descriptor desc;
 776         u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
 777         u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 778         struct kvec bufferlist[3];
 779         u64 aligned_data = 0;
 780         int num_vecs = ((bufferlen != 0) ? 3 : 1);
 781
 782
 783         /* Setup the descriptor */
 784         desc.type = type; /* VmbusPacketTypeDataInBand; */
 785         desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
 786         /* in 8-bytes granularity */
 787         desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3;
 788         desc.len8 = (u16)(packetlen_aligned >> 3);
 789         desc.trans_id = requestid;
 790
 791         bufferlist[0].iov_base = &desc;
 792         bufferlist[0].iov_len = sizeof(struct vmpacket_descriptor);
 793         bufferlist[1].iov_base = buffer;
 794         bufferlist[1].iov_len = bufferlen;
 795         bufferlist[2].iov_base = &aligned_data;
 796         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 797
 798         return hv_ringbuffer_write(channel, bufferlist, num_vecs);
 799 }
 800 EXPORT_SYMBOL(vmbus_sendpacket);
 801
 802 /*
 803  * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
 804  * packets using a GPADL Direct packet type. This interface allows you
 805  * to control notifying the host. This will be useful for sending
 806  * batched data. Also the sender can control the send flags
 807  * explicitly.
 808  */
 809 int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
 810                                 struct hv_page_buffer pagebuffers[],
 811                                 u32 pagecount, void *buffer, u32 bufferlen,
 812                                 u64 requestid)
 813 {
 814         int i;
 815         struct vmbus_channel_packet_page_buffer desc;
 816         u32 descsize;
 817         u32 packetlen;
 818         u32 packetlen_aligned;
 819         struct kvec bufferlist[3];
 820         u64 aligned_data = 0;
 821
 822         if (pagecount > MAX_PAGE_BUFFER_COUNT)
 823                 return -EINVAL;
 824
 825         /*
 826          * Adjust the size down since vmbus_channel_packet_page_buffer is the
 827          * largest size we support
 828          */
 829         descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
 830                           ((MAX_PAGE_BUFFER_COUNT - pagecount) *
 831                           sizeof(struct hv_page_buffer));
 832         packetlen = descsize + bufferlen;
 833         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 834
 835         /* Setup the descriptor */
 836         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
 837         desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 838         desc.dataoffset8 = descsize >> 3; /* in 8-bytes granularity */
 839         desc.length8 = (u16)(packetlen_aligned >> 3);
 840         desc.transactionid = requestid;
 841         desc.reserved = 0;
 842         desc.rangecount = pagecount;
 843
 844         for (i = 0; i < pagecount; i++) {
 845                 desc.range[i].len = pagebuffers[i].len;
 846                 desc.range[i].offset = pagebuffers[i].offset;
 847                 desc.range[i].pfn        = pagebuffers[i].pfn;
 848         }
 849
 850         bufferlist[0].iov_base = &desc;
 851         bufferlist[0].iov_len = descsize;
 852         bufferlist[1].iov_base = buffer;
 853         bufferlist[1].iov_len = bufferlen;
 854         bufferlist[2].iov_base = &aligned_data;
 855         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 856
 857         return hv_ringbuffer_write(channel, bufferlist, 3);
 858 }
 859 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
 860
 861 /*
 862  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
 863  * using a GPADL Direct packet type.
 864  * The buffer includes the vmbus descriptor.
 865  */
 866 int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
 867                               struct vmbus_packet_mpb_array *desc,
 868                               u32 desc_size,
 869                               void *buffer, u32 bufferlen, u64 requestid)
 870 {
 871         u32 packetlen;
 872         u32 packetlen_aligned;
 873         struct kvec bufferlist[3];
 874         u64 aligned_data = 0;
 875
 876         packetlen = desc_size + bufferlen;
 877         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 878
 879         /* Setup the descriptor */
 880         desc->type = VM_PKT_DATA_USING_GPA_DIRECT;
 881         desc->flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 882         desc->dataoffset8 = desc_size >> 3; /* in 8-bytes granularity */
 883         desc->length8 = (u16)(packetlen_aligned >> 3);
 884         desc->transactionid = requestid;
 885         desc->reserved = 0;
 886         desc->rangecount = 1;
 887
 888         bufferlist[0].iov_base = desc;
 889         bufferlist[0].iov_len = desc_size;
 890         bufferlist[1].iov_base = buffer;
 891         bufferlist[1].iov_len = bufferlen;
 892         bufferlist[2].iov_base = &aligned_data;
 893         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 894
 895         return hv_ringbuffer_write(channel, bufferlist, 3);
 896 }
 897 EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc);
 898
 899 /**
 900  * __vmbus_recvpacket() - Retrieve the user packet on the specified channel
 901  * @channel: Pointer to vmbus_channel structure
 902  * @buffer: Pointer to the buffer you want to receive the data into.
 903  * @bufferlen: Maximum size of what the buffer can hold.
 904  * @buffer_actual_len: The actual size of the data after it was received.
 905  * @requestid: Identifier of the request
 906  * @raw: true means keep the vmpacket_descriptor header in the received data.
 907  *
 908  * Receives directly from the hyper-v vmbus and puts the data it received
 909  * into Buffer. This will receive the data unparsed from hyper-v.
 910  *
 911  * Mainly used by Hyper-V drivers.
 912  */
 913 static inline int
 914 __vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
 915                    u32 bufferlen, u32 *buffer_actual_len, u64 *requestid,
 916                    bool raw)
 917 {
 918         return hv_ringbuffer_read(channel, buffer, bufferlen,
 919                                   buffer_actual_len, requestid, raw);
 920
 921 }
 922
 923 int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
 924                      u32 bufferlen, u32 *buffer_actual_len,
 925                      u64 *requestid)
 926 {
 927         return __vmbus_recvpacket(channel, buffer, bufferlen,
 928                                   buffer_actual_len, requestid, false);
 929 }
 930 EXPORT_SYMBOL(vmbus_recvpacket);
 931
 932 /*
 933  * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
 934  */
 935 int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
 936                               u32 bufferlen, u32 *buffer_actual_len,
 937                               u64 *requestid)
 938 {
 939         return __vmbus_recvpacket(channel, buffer, bufferlen,
 940                                   buffer_actual_len, requestid, true);
 941 }
 942 EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);