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 <haiyangz@microsoft.com>
   7  *   Hank Janssen  <hjanssen@microsoft.com>
   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  * create_gpadl_header - Creates a gpadl for the specified buffer
 294  */
 295 static int create_gpadl_header(void *kbuffer, u32 size,
 296                                struct vmbus_channel_msginfo **msginfo)
 297 {
 298         int i;
 299         int pagecount;
 300         struct vmbus_channel_gpadl_header *gpadl_header;
 301         struct vmbus_channel_gpadl_body *gpadl_body;
 302         struct vmbus_channel_msginfo *msgheader;
 303         struct vmbus_channel_msginfo *msgbody = NULL;
 304         u32 msgsize;
 305
 306         int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
 307
 308         pagecount = size >> PAGE_SHIFT;
 309
 310         /* do we need a gpadl body msg */
 311         pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 312                   sizeof(struct vmbus_channel_gpadl_header) -
 313                   sizeof(struct gpa_range);
 314         pfncount = pfnsize / sizeof(u64);
 315
 316         if (pagecount > pfncount) {
 317                 /* we need a gpadl body */
 318                 /* fill in the header */
 319                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 320                           sizeof(struct vmbus_channel_gpadl_header) +
 321                           sizeof(struct gpa_range) + pfncount * sizeof(u64);
 322                 msgheader =  kzalloc(msgsize, GFP_KERNEL);
 323                 if (!msgheader)
 324                         goto nomem;
 325
 326                 INIT_LIST_HEAD(&msgheader->submsglist);
 327                 msgheader->msgsize = msgsize;
 328
 329                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 330                         msgheader->msg;
 331                 gpadl_header->rangecount = 1;
 332                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 333                                          pagecount * sizeof(u64);
 334                 gpadl_header->range[0].byte_offset = 0;
 335                 gpadl_header->range[0].byte_count = size;
 336                 for (i = 0; i < pfncount; i++)
 337                         gpadl_header->range[0].pfn_array[i] = virt_to_hvpfn(
 338                                 kbuffer + PAGE_SIZE * i);
 339                 *msginfo = msgheader;
 340
 341                 pfnsum = pfncount;
 342                 pfnleft = pagecount - pfncount;
 343
 344                 /* how many pfns can we fit */
 345                 pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 346                           sizeof(struct vmbus_channel_gpadl_body);
 347                 pfncount = pfnsize / sizeof(u64);
 348
 349                 /* fill in the body */
 350                 while (pfnleft) {
 351                         if (pfnleft > pfncount)
 352                                 pfncurr = pfncount;
 353                         else
 354                                 pfncurr = pfnleft;
 355
 356                         msgsize = sizeof(struct vmbus_channel_msginfo) +
 357                                   sizeof(struct vmbus_channel_gpadl_body) +
 358                                   pfncurr * sizeof(u64);
 359                         msgbody = kzalloc(msgsize, GFP_KERNEL);
 360
 361                         if (!msgbody) {
 362                                 struct vmbus_channel_msginfo *pos = NULL;
 363                                 struct vmbus_channel_msginfo *tmp = NULL;
 364                                 /*
 365                                  * Free up all the allocated messages.
 366                                  */
 367                                 list_for_each_entry_safe(pos, tmp,
 368                                         &msgheader->submsglist,
 369                                         msglistentry) {
 370
 371                                         list_del(&pos->msglistentry);
 372                                         kfree(pos);
 373                                 }
 374
 375                                 goto nomem;
 376                         }
 377
 378                         msgbody->msgsize = msgsize;
 379                         gpadl_body =
 380                                 (struct vmbus_channel_gpadl_body *)msgbody->msg;
 381
 382                         /*
 383                          * Gpadl is u32 and we are using a pointer which could
 384                          * be 64-bit
 385                          * This is governed by the guest/host protocol and
 386                          * so the hypervisor guarantees that this is ok.
 387                          */
 388                         for (i = 0; i < pfncurr; i++)
 389                                 gpadl_body->pfn[i] = virt_to_hvpfn(
 390                                         kbuffer + PAGE_SIZE * (pfnsum + i));
 391
 392                         /* add to msg header */
 393                         list_add_tail(&msgbody->msglistentry,
 394                                       &msgheader->submsglist);
 395                         pfnsum += pfncurr;
 396                         pfnleft -= pfncurr;
 397                 }
 398         } else {
 399                 /* everything fits in a header */
 400                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 401                           sizeof(struct vmbus_channel_gpadl_header) +
 402                           sizeof(struct gpa_range) + pagecount * sizeof(u64);
 403                 msgheader = kzalloc(msgsize, GFP_KERNEL);
 404                 if (msgheader == NULL)
 405                         goto nomem;
 406
 407                 INIT_LIST_HEAD(&msgheader->submsglist);
 408                 msgheader->msgsize = msgsize;
 409
 410                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 411                         msgheader->msg;
 412                 gpadl_header->rangecount = 1;
 413                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 414                                          pagecount * sizeof(u64);
 415                 gpadl_header->range[0].byte_offset = 0;
 416                 gpadl_header->range[0].byte_count = size;
 417                 for (i = 0; i < pagecount; i++)
 418                         gpadl_header->range[0].pfn_array[i] = virt_to_hvpfn(
 419                                 kbuffer + PAGE_SIZE * i);
 420
 421                 *msginfo = msgheader;
 422         }
 423
 424         return 0;
 425 nomem:
 426         kfree(msgheader);
 427         kfree(msgbody);
 428         return -ENOMEM;
 429 }
 430
 431 /*
 432  * vmbus_establish_gpadl - Establish a GPADL for the specified buffer
 433  *
 434  * @channel: a channel
 435  * @kbuffer: from kmalloc or vmalloc
 436  * @size: page-size multiple
 437  * @gpadl_handle: some funky thing
 438  */
 439 int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
 440                                u32 size, u32 *gpadl_handle)
 441 {
 442         struct vmbus_channel_gpadl_header *gpadlmsg;
 443         struct vmbus_channel_gpadl_body *gpadl_body;
 444         struct vmbus_channel_msginfo *msginfo = NULL;
 445         struct vmbus_channel_msginfo *submsginfo, *tmp;
 446         struct list_head *curr;
 447         u32 next_gpadl_handle;
 448         unsigned long flags;
 449         int ret = 0;
 450
 451         next_gpadl_handle =
 452                 (atomic_inc_return(&vmbus_connection.next_gpadl_handle) - 1);
 453
 454         ret = create_gpadl_header(kbuffer, size, &msginfo);
 455         if (ret)
 456                 return ret;
 457
 458         init_completion(&msginfo->waitevent);
 459         msginfo->waiting_channel = channel;
 460
 461         gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
 462         gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
 463         gpadlmsg->child_relid = channel->offermsg.child_relid;
 464         gpadlmsg->gpadl = next_gpadl_handle;
 465
 466
 467         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 468         list_add_tail(&msginfo->msglistentry,
 469                       &vmbus_connection.chn_msg_list);
 470
 471         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 472
 473         if (channel->rescind) {
 474                 ret = -ENODEV;
 475                 goto cleanup;
 476         }
 477
 478         ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize -
 479                              sizeof(*msginfo), true);
 480
 481         trace_vmbus_establish_gpadl_header(gpadlmsg, ret);
 482
 483         if (ret != 0)
 484                 goto cleanup;
 485
 486         list_for_each(curr, &msginfo->submsglist) {
 487                 submsginfo = (struct vmbus_channel_msginfo *)curr;
 488                 gpadl_body =
 489                         (struct vmbus_channel_gpadl_body *)submsginfo->msg;
 490
 491                 gpadl_body->header.msgtype =
 492                         CHANNELMSG_GPADL_BODY;
 493                 gpadl_body->gpadl = next_gpadl_handle;
 494
 495                 ret = vmbus_post_msg(gpadl_body,
 496                                      submsginfo->msgsize - sizeof(*submsginfo),
 497                                      true);
 498
 499                 trace_vmbus_establish_gpadl_body(gpadl_body, ret);
 500
 501                 if (ret != 0)
 502                         goto cleanup;
 503
 504         }
 505         wait_for_completion(&msginfo->waitevent);
 506
 507         if (msginfo->response.gpadl_created.creation_status != 0) {
 508                 pr_err("Failed to establish GPADL: err = 0x%x\n",
 509                        msginfo->response.gpadl_created.creation_status);
 510
 511                 ret = -EDQUOT;
 512                 goto cleanup;
 513         }
 514
 515         if (channel->rescind) {
 516                 ret = -ENODEV;
 517                 goto cleanup;
 518         }
 519
 520         /* At this point, we received the gpadl created msg */
 521         *gpadl_handle = gpadlmsg->gpadl;
 522
 523 cleanup:
 524         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 525         list_del(&msginfo->msglistentry);
 526         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 527         list_for_each_entry_safe(submsginfo, tmp, &msginfo->submsglist,
 528                                  msglistentry) {
 529                 kfree(submsginfo);
 530         }
 531
 532         kfree(msginfo);
 533         return ret;
 534 }
 535 EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
 536
 537 /*
 538  * vmbus_teardown_gpadl -Teardown the specified GPADL handle
 539  */
 540 int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
 541 {
 542         struct vmbus_channel_gpadl_teardown *msg;
 543         struct vmbus_channel_msginfo *info;
 544         unsigned long flags;
 545         int ret;
 546
 547         info = kmalloc(sizeof(*info) +
 548                        sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
 549         if (!info)
 550                 return -ENOMEM;
 551
 552         init_completion(&info->waitevent);
 553         info->waiting_channel = channel;
 554
 555         msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
 556
 557         msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
 558         msg->child_relid = channel->offermsg.child_relid;
 559         msg->gpadl = gpadl_handle;
 560
 561         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 562         list_add_tail(&info->msglistentry,
 563                       &vmbus_connection.chn_msg_list);
 564         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 565
 566         if (channel->rescind)
 567                 goto post_msg_err;
 568
 569         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_gpadl_teardown),
 570                              true);
 571
 572         trace_vmbus_teardown_gpadl(msg, ret);
 573
 574         if (ret)
 575                 goto post_msg_err;
 576
 577         wait_for_completion(&info->waitevent);
 578
 579 post_msg_err:
 580         /*
 581          * If the channel has been rescinded;
 582          * we will be awakened by the rescind
 583          * handler; set the error code to zero so we don't leak memory.
 584          */
 585         if (channel->rescind)
 586                 ret = 0;
 587
 588         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 589         list_del(&info->msglistentry);
 590         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 591
 592         kfree(info);
 593         return ret;
 594 }
 595 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
 596
 597 static void reset_channel_cb(void *arg)
 598 {
 599         struct vmbus_channel *channel = arg;
 600
 601         channel->onchannel_callback = NULL;
 602 }
 603
 604 void vmbus_reset_channel_cb(struct vmbus_channel *channel)
 605 {
 606         /*
 607          * vmbus_on_event(), running in the per-channel tasklet, can race
 608          * with vmbus_close_internal() in the case of SMP guest, e.g., when
 609          * the former is accessing channel->inbound.ring_buffer, the latter
 610          * could be freeing the ring_buffer pages, so here we must stop it
 611          * first.
 612          */
 613         tasklet_disable(&channel->callback_event);
 614
 615         channel->sc_creation_callback = NULL;
 616
 617         /* Stop the callback asap */
 618         if (channel->target_cpu != get_cpu()) {
 619                 put_cpu();
 620                 smp_call_function_single(channel->target_cpu, reset_channel_cb,
 621                                          channel, true);
 622         } else {
 623                 reset_channel_cb(channel);
 624                 put_cpu();
 625         }
 626
 627         /* Re-enable tasklet for use on re-open */
 628         tasklet_enable(&channel->callback_event);
 629 }
 630
 631 static int vmbus_close_internal(struct vmbus_channel *channel)
 632 {
 633         struct vmbus_channel_close_channel *msg;
 634         int ret;
 635
 636         vmbus_reset_channel_cb(channel);
 637
 638         /*
 639          * In case a device driver's probe() fails (e.g.,
 640          * util_probe() -> vmbus_open() returns -ENOMEM) and the device is
 641          * rescinded later (e.g., we dynamically disable an Integrated Service
 642          * in Hyper-V Manager), the driver's remove() invokes vmbus_close():
 643          * here we should skip most of the below cleanup work.
 644          */
 645         if (channel->state != CHANNEL_OPENED_STATE)
 646                 return -EINVAL;
 647
 648         channel->state = CHANNEL_OPEN_STATE;
 649
 650         /* Send a closing message */
 651
 652         msg = &channel->close_msg.msg;
 653
 654         msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
 655         msg->child_relid = channel->offermsg.child_relid;
 656
 657         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel),
 658                              true);
 659
 660         trace_vmbus_close_internal(msg, ret);
 661
 662         if (ret) {
 663                 pr_err("Close failed: close post msg return is %d\n", ret);
 664                 /*
 665                  * If we failed to post the close msg,
 666                  * it is perhaps better to leak memory.
 667                  */
 668         }
 669
 670         /* Tear down the gpadl for the channel's ring buffer */
 671         else if (channel->ringbuffer_gpadlhandle) {
 672                 ret = vmbus_teardown_gpadl(channel,
 673                                            channel->ringbuffer_gpadlhandle);
 674                 if (ret) {
 675                         pr_err("Close failed: teardown gpadl return %d\n", ret);
 676                         /*
 677                          * If we failed to teardown gpadl,
 678                          * it is perhaps better to leak memory.
 679                          */
 680                 }
 681
 682                 channel->ringbuffer_gpadlhandle = 0;
 683         }
 684
 685         return ret;
 686 }
 687
 688 /* disconnect ring - close all channels */
 689 int vmbus_disconnect_ring(struct vmbus_channel *channel)
 690 {
 691         struct vmbus_channel *cur_channel, *tmp;
 692         int ret;
 693
 694         if (channel->primary_channel != NULL)
 695                 return -EINVAL;
 696
 697         list_for_each_entry_safe(cur_channel, tmp, &channel->sc_list, sc_list) {
 698                 if (cur_channel->rescind)
 699                         wait_for_completion(&cur_channel->rescind_event);
 700
 701                 mutex_lock(&vmbus_connection.channel_mutex);
 702                 if (vmbus_close_internal(cur_channel) == 0) {
 703                         vmbus_free_ring(cur_channel);
 704
 705                         if (cur_channel->rescind)
 706                                 hv_process_channel_removal(cur_channel);
 707                 }
 708                 mutex_unlock(&vmbus_connection.channel_mutex);
 709         }
 710
 711         /*
 712          * Now close the primary.
 713          */
 714         mutex_lock(&vmbus_connection.channel_mutex);
 715         ret = vmbus_close_internal(channel);
 716         mutex_unlock(&vmbus_connection.channel_mutex);
 717
 718         return ret;
 719 }
 720 EXPORT_SYMBOL_GPL(vmbus_disconnect_ring);
 721
 722 /*
 723  * vmbus_close - Close the specified channel
 724  */
 725 void vmbus_close(struct vmbus_channel *channel)
 726 {
 727         if (vmbus_disconnect_ring(channel) == 0)
 728                 vmbus_free_ring(channel);
 729 }
 730 EXPORT_SYMBOL_GPL(vmbus_close);
 731
 732 /**
 733  * vmbus_sendpacket() - Send the specified buffer on the given channel
 734  * @channel: Pointer to vmbus_channel structure
 735  * @buffer: Pointer to the buffer you want to send the data from.
 736  * @bufferlen: Maximum size of what the buffer holds.
 737  * @requestid: Identifier of the request
 738  * @type: Type of packet that is being sent e.g. negotiate, time
 739  *        packet etc.
 740  * @flags: 0 or VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED
 741  *
 742  * Sends data in @buffer directly to Hyper-V via the vmbus.
 743  * This will send the data unparsed to Hyper-V.
 744  *
 745  * Mainly used by Hyper-V drivers.
 746  */
 747 int vmbus_sendpacket(struct vmbus_channel *channel, void *buffer,
 748                            u32 bufferlen, u64 requestid,
 749                            enum vmbus_packet_type type, u32 flags)
 750 {
 751         struct vmpacket_descriptor desc;
 752         u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
 753         u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 754         struct kvec bufferlist[3];
 755         u64 aligned_data = 0;
 756         int num_vecs = ((bufferlen != 0) ? 3 : 1);
 757
 758
 759         /* Setup the descriptor */
 760         desc.type = type; /* VmbusPacketTypeDataInBand; */
 761         desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
 762         /* in 8-bytes granularity */
 763         desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3;
 764         desc.len8 = (u16)(packetlen_aligned >> 3);
 765         desc.trans_id = requestid;
 766
 767         bufferlist[0].iov_base = &desc;
 768         bufferlist[0].iov_len = sizeof(struct vmpacket_descriptor);
 769         bufferlist[1].iov_base = buffer;
 770         bufferlist[1].iov_len = bufferlen;
 771         bufferlist[2].iov_base = &aligned_data;
 772         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 773
 774         return hv_ringbuffer_write(channel, bufferlist, num_vecs);
 775 }
 776 EXPORT_SYMBOL(vmbus_sendpacket);
 777
 778 /*
 779  * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
 780  * packets using a GPADL Direct packet type. This interface allows you
 781  * to control notifying the host. This will be useful for sending
 782  * batched data. Also the sender can control the send flags
 783  * explicitly.
 784  */
 785 int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
 786                                 struct hv_page_buffer pagebuffers[],
 787                                 u32 pagecount, void *buffer, u32 bufferlen,
 788                                 u64 requestid)
 789 {
 790         int i;
 791         struct vmbus_channel_packet_page_buffer desc;
 792         u32 descsize;
 793         u32 packetlen;
 794         u32 packetlen_aligned;
 795         struct kvec bufferlist[3];
 796         u64 aligned_data = 0;
 797
 798         if (pagecount > MAX_PAGE_BUFFER_COUNT)
 799                 return -EINVAL;
 800
 801         /*
 802          * Adjust the size down since vmbus_channel_packet_page_buffer is the
 803          * largest size we support
 804          */
 805         descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
 806                           ((MAX_PAGE_BUFFER_COUNT - pagecount) *
 807                           sizeof(struct hv_page_buffer));
 808         packetlen = descsize + bufferlen;
 809         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 810
 811         /* Setup the descriptor */
 812         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
 813         desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 814         desc.dataoffset8 = descsize >> 3; /* in 8-bytes granularity */
 815         desc.length8 = (u16)(packetlen_aligned >> 3);
 816         desc.transactionid = requestid;
 817         desc.reserved = 0;
 818         desc.rangecount = pagecount;
 819
 820         for (i = 0; i < pagecount; i++) {
 821                 desc.range[i].len = pagebuffers[i].len;
 822                 desc.range[i].offset = pagebuffers[i].offset;
 823                 desc.range[i].pfn        = pagebuffers[i].pfn;
 824         }
 825
 826         bufferlist[0].iov_base = &desc;
 827         bufferlist[0].iov_len = descsize;
 828         bufferlist[1].iov_base = buffer;
 829         bufferlist[1].iov_len = bufferlen;
 830         bufferlist[2].iov_base = &aligned_data;
 831         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 832
 833         return hv_ringbuffer_write(channel, bufferlist, 3);
 834 }
 835 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
 836
 837 /*
 838  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
 839  * using a GPADL Direct packet type.
 840  * The buffer includes the vmbus descriptor.
 841  */
 842 int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
 843                               struct vmbus_packet_mpb_array *desc,
 844                               u32 desc_size,
 845                               void *buffer, u32 bufferlen, u64 requestid)
 846 {
 847         u32 packetlen;
 848         u32 packetlen_aligned;
 849         struct kvec bufferlist[3];
 850         u64 aligned_data = 0;
 851
 852         packetlen = desc_size + bufferlen;
 853         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 854
 855         /* Setup the descriptor */
 856         desc->type = VM_PKT_DATA_USING_GPA_DIRECT;
 857         desc->flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 858         desc->dataoffset8 = desc_size >> 3; /* in 8-bytes granularity */
 859         desc->length8 = (u16)(packetlen_aligned >> 3);
 860         desc->transactionid = requestid;
 861         desc->reserved = 0;
 862         desc->rangecount = 1;
 863
 864         bufferlist[0].iov_base = desc;
 865         bufferlist[0].iov_len = desc_size;
 866         bufferlist[1].iov_base = buffer;
 867         bufferlist[1].iov_len = bufferlen;
 868         bufferlist[2].iov_base = &aligned_data;
 869         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 870
 871         return hv_ringbuffer_write(channel, bufferlist, 3);
 872 }
 873 EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc);
 874
 875 /**
 876  * __vmbus_recvpacket() - Retrieve the user packet on the specified channel
 877  * @channel: Pointer to vmbus_channel structure
 878  * @buffer: Pointer to the buffer you want to receive the data into.
 879  * @bufferlen: Maximum size of what the buffer can hold.
 880  * @buffer_actual_len: The actual size of the data after it was received.
 881  * @requestid: Identifier of the request
 882  * @raw: true means keep the vmpacket_descriptor header in the received data.
 883  *
 884  * Receives directly from the hyper-v vmbus and puts the data it received
 885  * into Buffer. This will receive the data unparsed from hyper-v.
 886  *
 887  * Mainly used by Hyper-V drivers.
 888  */
 889 static inline int
 890 __vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
 891                    u32 bufferlen, u32 *buffer_actual_len, u64 *requestid,
 892                    bool raw)
 893 {
 894         return hv_ringbuffer_read(channel, buffer, bufferlen,
 895                                   buffer_actual_len, requestid, raw);
 896
 897 }
 898
 899 int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
 900                      u32 bufferlen, u32 *buffer_actual_len,
 901                      u64 *requestid)
 902 {
 903         return __vmbus_recvpacket(channel, buffer, bufferlen,
 904                                   buffer_actual_len, requestid, false);
 905 }
 906 EXPORT_SYMBOL(vmbus_recvpacket);
 907
 908 /*
 909  * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
 910  */
 911 int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
 912                               u32 bufferlen, u32 *buffer_actual_len,
 913                               u64 *requestid)
 914 {
 915         return __vmbus_recvpacket(channel, buffer, bufferlen,
 916                                   buffer_actual_len, requestid, true);
 917 }
 918 EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);