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 #include <asm/mshyperv.h>
  22
  23 #include "hyperv_vmbus.h"
  24
  25 /*
  26  * hv_gpadl_size - Return the real size of a gpadl, the size that Hyper-V uses
  27  *
  28  * For BUFFER gpadl, Hyper-V uses the exact same size as the guest does.
  29  *
  30  * For RING gpadl, in each ring, the guest uses one PAGE_SIZE as the header
  31  * (because of the alignment requirement), however, the hypervisor only
  32  * uses the first HV_HYP_PAGE_SIZE as the header, therefore leaving a
  33  * (PAGE_SIZE - HV_HYP_PAGE_SIZE) gap. And since there are two rings in a
  34  * ringbuffer, the total size for a RING gpadl that Hyper-V uses is the
  35  * total size that the guest uses minus twice of the gap size.
  36  */
  37 static inline u32 hv_gpadl_size(enum hv_gpadl_type type, u32 size)
  38 {
  39         switch (type) {
  40         case HV_GPADL_BUFFER:
  41                 return size;
  42         case HV_GPADL_RING:
  43                 /* The size of a ringbuffer must be page-aligned */
  44                 BUG_ON(size % PAGE_SIZE);
  45                 /*
  46                  * Two things to notice here:
  47                  * 1) We're processing two ring buffers as a unit
  48                  * 2) We're skipping any space larger than HV_HYP_PAGE_SIZE in
  49                  * the first guest-size page of each of the two ring buffers.
  50                  * So we effectively subtract out two guest-size pages, and add
  51                  * back two Hyper-V size pages.
  52                  */
  53                 return size - 2 * (PAGE_SIZE - HV_HYP_PAGE_SIZE);
  54         }
  55         BUG();
  56         return 0;
  57 }
  58
  59 /*
  60  * hv_ring_gpadl_send_hvpgoffset - Calculate the send offset (in unit of
  61  *                                 HV_HYP_PAGE) in a ring gpadl based on the
  62  *                                 offset in the guest
  63  *
  64  * @offset: the offset (in bytes) where the send ringbuffer starts in the
  65  *               virtual address space of the guest
  66  */
  67 static inline u32 hv_ring_gpadl_send_hvpgoffset(u32 offset)
  68 {
  69
  70         /*
  71          * For RING gpadl, in each ring, the guest uses one PAGE_SIZE as the
  72          * header (because of the alignment requirement), however, the
  73          * hypervisor only uses the first HV_HYP_PAGE_SIZE as the header,
  74          * therefore leaving a (PAGE_SIZE - HV_HYP_PAGE_SIZE) gap.
  75          *
  76          * And to calculate the effective send offset in gpadl, we need to
  77          * substract this gap.
  78          */
  79         return (offset - (PAGE_SIZE - HV_HYP_PAGE_SIZE)) >> HV_HYP_PAGE_SHIFT;
  80 }
  81
  82 /*
  83  * hv_gpadl_hvpfn - Return the Hyper-V page PFN of the @i th Hyper-V page in
  84  *                  the gpadl
  85  *
  86  * @type: the type of the gpadl
  87  * @kbuffer: the pointer to the gpadl in the guest
  88  * @size: the total size (in bytes) of the gpadl
  89  * @send_offset: the offset (in bytes) where the send ringbuffer starts in the
  90  *               virtual address space of the guest
  91  * @i: the index
  92  */
  93 static inline u64 hv_gpadl_hvpfn(enum hv_gpadl_type type, void *kbuffer,
  94                                  u32 size, u32 send_offset, int i)
  95 {
  96         int send_idx = hv_ring_gpadl_send_hvpgoffset(send_offset);
  97         unsigned long delta = 0UL;
  98
  99         switch (type) {
 100         case HV_GPADL_BUFFER:
 101                 break;
 102         case HV_GPADL_RING:
 103                 if (i == 0)
 104                         delta = 0;
 105                 else if (i <= send_idx)
 106                         delta = PAGE_SIZE - HV_HYP_PAGE_SIZE;
 107                 else
 108                         delta = 2 * (PAGE_SIZE - HV_HYP_PAGE_SIZE);
 109                 break;
 110         default:
 111                 BUG();
 112                 break;
 113         }
 114
 115         return virt_to_hvpfn(kbuffer + delta + (HV_HYP_PAGE_SIZE * i));
 116 }
 117
 118 /*
 119  * vmbus_setevent- Trigger an event notification on the specified
 120  * channel.
 121  */
 122 void vmbus_setevent(struct vmbus_channel *channel)
 123 {
 124         struct hv_monitor_page *monitorpage;
 125
 126         trace_vmbus_setevent(channel);
 127
 128         /*
 129          * For channels marked as in "low latency" mode
 130          * bypass the monitor page mechanism.
 131          */
 132         if (channel->offermsg.monitor_allocated && !channel->low_latency) {
 133                 vmbus_send_interrupt(channel->offermsg.child_relid);
 134
 135                 /* Get the child to parent monitor page */
 136                 monitorpage = vmbus_connection.monitor_pages[1];
 137
 138                 sync_set_bit(channel->monitor_bit,
 139                         (unsigned long *)&monitorpage->trigger_group
 140                                         [channel->monitor_grp].pending);
 141
 142         } else {
 143                 vmbus_set_event(channel);
 144         }
 145 }
 146 EXPORT_SYMBOL_GPL(vmbus_setevent);
 147
 148 /* vmbus_free_ring - drop mapping of ring buffer */
 149 void vmbus_free_ring(struct vmbus_channel *channel)
 150 {
 151         hv_ringbuffer_cleanup(&channel->outbound);
 152         hv_ringbuffer_cleanup(&channel->inbound);
 153
 154         if (channel->ringbuffer_page) {
 155                 __free_pages(channel->ringbuffer_page,
 156                              get_order(channel->ringbuffer_pagecount
 157                                        << PAGE_SHIFT));
 158                 channel->ringbuffer_page = NULL;
 159         }
 160 }
 161 EXPORT_SYMBOL_GPL(vmbus_free_ring);
 162
 163 /* vmbus_alloc_ring - allocate and map pages for ring buffer */
 164 int vmbus_alloc_ring(struct vmbus_channel *newchannel,
 165                      u32 send_size, u32 recv_size)
 166 {
 167         struct page *page;
 168         int order;
 169
 170         if (send_size % PAGE_SIZE || recv_size % PAGE_SIZE)
 171                 return -EINVAL;
 172
 173         /* Allocate the ring buffer */
 174         order = get_order(send_size + recv_size);
 175         page = alloc_pages_node(cpu_to_node(newchannel->target_cpu),
 176                                 GFP_KERNEL|__GFP_ZERO, order);
 177
 178         if (!page)
 179                 page = alloc_pages(GFP_KERNEL|__GFP_ZERO, order);
 180
 181         if (!page)
 182                 return -ENOMEM;
 183
 184         newchannel->ringbuffer_page = page;
 185         newchannel->ringbuffer_pagecount = (send_size + recv_size) >> PAGE_SHIFT;
 186         newchannel->ringbuffer_send_offset = send_size >> PAGE_SHIFT;
 187
 188         return 0;
 189 }
 190 EXPORT_SYMBOL_GPL(vmbus_alloc_ring);
 191
 192 /* Used for Hyper-V Socket: a guest client's connect() to the host */
 193 int vmbus_send_tl_connect_request(const guid_t *shv_guest_servie_id,
 194                                   const guid_t *shv_host_servie_id)
 195 {
 196         struct vmbus_channel_tl_connect_request conn_msg;
 197         int ret;
 198
 199         memset(&conn_msg, 0, sizeof(conn_msg));
 200         conn_msg.header.msgtype = CHANNELMSG_TL_CONNECT_REQUEST;
 201         conn_msg.guest_endpoint_id = *shv_guest_servie_id;
 202         conn_msg.host_service_id = *shv_host_servie_id;
 203
 204         ret = vmbus_post_msg(&conn_msg, sizeof(conn_msg), true);
 205
 206         trace_vmbus_send_tl_connect_request(&conn_msg, ret);
 207
 208         return ret;
 209 }
 210 EXPORT_SYMBOL_GPL(vmbus_send_tl_connect_request);
 211
 212 /*
 213  * Set/change the vCPU (@target_vp) the channel (@child_relid) will interrupt.
 214  *
 215  * CHANNELMSG_MODIFYCHANNEL messages are aynchronous.  Also, Hyper-V does not
 216  * ACK such messages.  IOW we can't know when the host will stop interrupting
 217  * the "old" vCPU and start interrupting the "new" vCPU for the given channel.
 218  *
 219  * The CHANNELMSG_MODIFYCHANNEL message type is supported since VMBus version
 220  * VERSION_WIN10_V4_1.
 221  */
 222 int vmbus_send_modifychannel(u32 child_relid, u32 target_vp)
 223 {
 224         struct vmbus_channel_modifychannel conn_msg;
 225         int ret;
 226
 227         memset(&conn_msg, 0, sizeof(conn_msg));
 228         conn_msg.header.msgtype = CHANNELMSG_MODIFYCHANNEL;
 229         conn_msg.child_relid = child_relid;
 230         conn_msg.target_vp = target_vp;
 231
 232         ret = vmbus_post_msg(&conn_msg, sizeof(conn_msg), true);
 233
 234         trace_vmbus_send_modifychannel(&conn_msg, ret);
 235
 236         return ret;
 237 }
 238 EXPORT_SYMBOL_GPL(vmbus_send_modifychannel);
 239
 240 /*
 241  * create_gpadl_header - Creates a gpadl for the specified buffer
 242  */
 243 static int create_gpadl_header(enum hv_gpadl_type type, void *kbuffer,
 244                                u32 size, u32 send_offset,
 245                                struct vmbus_channel_msginfo **msginfo)
 246 {
 247         int i;
 248         int pagecount;
 249         struct vmbus_channel_gpadl_header *gpadl_header;
 250         struct vmbus_channel_gpadl_body *gpadl_body;
 251         struct vmbus_channel_msginfo *msgheader;
 252         struct vmbus_channel_msginfo *msgbody = NULL;
 253         u32 msgsize;
 254
 255         int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
 256
 257         pagecount = hv_gpadl_size(type, size) >> HV_HYP_PAGE_SHIFT;
 258
 259         /* do we need a gpadl body msg */
 260         pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 261                   sizeof(struct vmbus_channel_gpadl_header) -
 262                   sizeof(struct gpa_range);
 263         pfncount = pfnsize / sizeof(u64);
 264
 265         if (pagecount > pfncount) {
 266                 /* we need a gpadl body */
 267                 /* fill in the header */
 268                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 269                           sizeof(struct vmbus_channel_gpadl_header) +
 270                           sizeof(struct gpa_range) + pfncount * sizeof(u64);
 271                 msgheader =  kzalloc(msgsize, GFP_KERNEL);
 272                 if (!msgheader)
 273                         goto nomem;
 274
 275                 INIT_LIST_HEAD(&msgheader->submsglist);
 276                 msgheader->msgsize = msgsize;
 277
 278                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 279                         msgheader->msg;
 280                 gpadl_header->rangecount = 1;
 281                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 282                                          pagecount * sizeof(u64);
 283                 gpadl_header->range[0].byte_offset = 0;
 284                 gpadl_header->range[0].byte_count = hv_gpadl_size(type, size);
 285                 for (i = 0; i < pfncount; i++)
 286                         gpadl_header->range[0].pfn_array[i] = hv_gpadl_hvpfn(
 287                                 type, kbuffer, size, send_offset, i);
 288                 *msginfo = msgheader;
 289
 290                 pfnsum = pfncount;
 291                 pfnleft = pagecount - pfncount;
 292
 293                 /* how many pfns can we fit */
 294                 pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 295                           sizeof(struct vmbus_channel_gpadl_body);
 296                 pfncount = pfnsize / sizeof(u64);
 297
 298                 /* fill in the body */
 299                 while (pfnleft) {
 300                         if (pfnleft > pfncount)
 301                                 pfncurr = pfncount;
 302                         else
 303                                 pfncurr = pfnleft;
 304
 305                         msgsize = sizeof(struct vmbus_channel_msginfo) +
 306                                   sizeof(struct vmbus_channel_gpadl_body) +
 307                                   pfncurr * sizeof(u64);
 308                         msgbody = kzalloc(msgsize, GFP_KERNEL);
 309
 310                         if (!msgbody) {
 311                                 struct vmbus_channel_msginfo *pos = NULL;
 312                                 struct vmbus_channel_msginfo *tmp = NULL;
 313                                 /*
 314                                  * Free up all the allocated messages.
 315                                  */
 316                                 list_for_each_entry_safe(pos, tmp,
 317                                         &msgheader->submsglist,
 318                                         msglistentry) {
 319
 320                                         list_del(&pos->msglistentry);
 321                                         kfree(pos);
 322                                 }
 323
 324                                 goto nomem;
 325                         }
 326
 327                         msgbody->msgsize = msgsize;
 328                         gpadl_body =
 329                                 (struct vmbus_channel_gpadl_body *)msgbody->msg;
 330
 331                         /*
 332                          * Gpadl is u32 and we are using a pointer which could
 333                          * be 64-bit
 334                          * This is governed by the guest/host protocol and
 335                          * so the hypervisor guarantees that this is ok.
 336                          */
 337                         for (i = 0; i < pfncurr; i++)
 338                                 gpadl_body->pfn[i] = hv_gpadl_hvpfn(type,
 339                                         kbuffer, size, send_offset, pfnsum + i);
 340
 341                         /* add to msg header */
 342                         list_add_tail(&msgbody->msglistentry,
 343                                       &msgheader->submsglist);
 344                         pfnsum += pfncurr;
 345                         pfnleft -= pfncurr;
 346                 }
 347         } else {
 348                 /* everything fits in a header */
 349                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 350                           sizeof(struct vmbus_channel_gpadl_header) +
 351                           sizeof(struct gpa_range) + pagecount * sizeof(u64);
 352                 msgheader = kzalloc(msgsize, GFP_KERNEL);
 353                 if (msgheader == NULL)
 354                         goto nomem;
 355
 356                 INIT_LIST_HEAD(&msgheader->submsglist);
 357                 msgheader->msgsize = msgsize;
 358
 359                 gpadl_header = (struct vmbus_channel_gpadl_header *)
 360                         msgheader->msg;
 361                 gpadl_header->rangecount = 1;
 362                 gpadl_header->range_buflen = sizeof(struct gpa_range) +
 363                                          pagecount * sizeof(u64);
 364                 gpadl_header->range[0].byte_offset = 0;
 365                 gpadl_header->range[0].byte_count = hv_gpadl_size(type, size);
 366                 for (i = 0; i < pagecount; i++)
 367                         gpadl_header->range[0].pfn_array[i] = hv_gpadl_hvpfn(
 368                                 type, kbuffer, size, send_offset, i);
 369
 370                 *msginfo = msgheader;
 371         }
 372
 373         return 0;
 374 nomem:
 375         kfree(msgheader);
 376         kfree(msgbody);
 377         return -ENOMEM;
 378 }
 379
 380 /*
 381  * __vmbus_establish_gpadl - Establish a GPADL for a buffer or ringbuffer
 382  *
 383  * @channel: a channel
 384  * @type: the type of the corresponding GPADL, only meaningful for the guest.
 385  * @kbuffer: from kmalloc or vmalloc
 386  * @size: page-size multiple
 387  * @send_offset: the offset (in bytes) where the send ring buffer starts,
 388  *               should be 0 for BUFFER type gpadl
 389  * @gpadl_handle: some funky thing
 390  */
 391 static int __vmbus_establish_gpadl(struct vmbus_channel *channel,
 392                                    enum hv_gpadl_type type, void *kbuffer,
 393                                    u32 size, u32 send_offset,
 394                                    u32 *gpadl_handle)
 395 {
 396         struct vmbus_channel_gpadl_header *gpadlmsg;
 397         struct vmbus_channel_gpadl_body *gpadl_body;
 398         struct vmbus_channel_msginfo *msginfo = NULL;
 399         struct vmbus_channel_msginfo *submsginfo, *tmp;
 400         struct list_head *curr;
 401         u32 next_gpadl_handle;
 402         unsigned long flags;
 403         int ret = 0;
 404
 405         next_gpadl_handle =
 406                 (atomic_inc_return(&vmbus_connection.next_gpadl_handle) - 1);
 407
 408         ret = create_gpadl_header(type, kbuffer, size, send_offset, &msginfo);
 409         if (ret)
 410                 return ret;
 411
 412         init_completion(&msginfo->waitevent);
 413         msginfo->waiting_channel = channel;
 414
 415         gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
 416         gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
 417         gpadlmsg->child_relid = channel->offermsg.child_relid;
 418         gpadlmsg->gpadl = next_gpadl_handle;
 419
 420
 421         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 422         list_add_tail(&msginfo->msglistentry,
 423                       &vmbus_connection.chn_msg_list);
 424
 425         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 426
 427         if (channel->rescind) {
 428                 ret = -ENODEV;
 429                 goto cleanup;
 430         }
 431
 432         ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize -
 433                              sizeof(*msginfo), true);
 434
 435         trace_vmbus_establish_gpadl_header(gpadlmsg, ret);
 436
 437         if (ret != 0)
 438                 goto cleanup;
 439
 440         list_for_each(curr, &msginfo->submsglist) {
 441                 submsginfo = (struct vmbus_channel_msginfo *)curr;
 442                 gpadl_body =
 443                         (struct vmbus_channel_gpadl_body *)submsginfo->msg;
 444
 445                 gpadl_body->header.msgtype =
 446                         CHANNELMSG_GPADL_BODY;
 447                 gpadl_body->gpadl = next_gpadl_handle;
 448
 449                 ret = vmbus_post_msg(gpadl_body,
 450                                      submsginfo->msgsize - sizeof(*submsginfo),
 451                                      true);
 452
 453                 trace_vmbus_establish_gpadl_body(gpadl_body, ret);
 454
 455                 if (ret != 0)
 456                         goto cleanup;
 457
 458         }
 459         wait_for_completion(&msginfo->waitevent);
 460
 461         if (msginfo->response.gpadl_created.creation_status != 0) {
 462                 pr_err("Failed to establish GPADL: err = 0x%x\n",
 463                        msginfo->response.gpadl_created.creation_status);
 464
 465                 ret = -EDQUOT;
 466                 goto cleanup;
 467         }
 468
 469         if (channel->rescind) {
 470                 ret = -ENODEV;
 471                 goto cleanup;
 472         }
 473
 474         /* At this point, we received the gpadl created msg */
 475         *gpadl_handle = gpadlmsg->gpadl;
 476
 477 cleanup:
 478         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 479         list_del(&msginfo->msglistentry);
 480         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 481         list_for_each_entry_safe(submsginfo, tmp, &msginfo->submsglist,
 482                                  msglistentry) {
 483                 kfree(submsginfo);
 484         }
 485
 486         kfree(msginfo);
 487         return ret;
 488 }
 489
 490 /*
 491  * vmbus_establish_gpadl - Establish a GPADL for the specified buffer
 492  *
 493  * @channel: a channel
 494  * @kbuffer: from kmalloc or vmalloc
 495  * @size: page-size multiple
 496  * @gpadl_handle: some funky thing
 497  */
 498 int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
 499                           u32 size, u32 *gpadl_handle)
 500 {
 501         return __vmbus_establish_gpadl(channel, HV_GPADL_BUFFER, kbuffer, size,
 502                                        0U, gpadl_handle);
 503 }
 504 EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
 505
 506 static int __vmbus_open(struct vmbus_channel *newchannel,
 507                        void *userdata, u32 userdatalen,
 508                        void (*onchannelcallback)(void *context), void *context)
 509 {
 510         struct vmbus_channel_open_channel *open_msg;
 511         struct vmbus_channel_msginfo *open_info = NULL;
 512         struct page *page = newchannel->ringbuffer_page;
 513         u32 send_pages, recv_pages;
 514         unsigned long flags;
 515         int err;
 516
 517         if (userdatalen > MAX_USER_DEFINED_BYTES)
 518                 return -EINVAL;
 519
 520         send_pages = newchannel->ringbuffer_send_offset;
 521         recv_pages = newchannel->ringbuffer_pagecount - send_pages;
 522
 523         if (newchannel->state != CHANNEL_OPEN_STATE)
 524                 return -EINVAL;
 525
 526         newchannel->state = CHANNEL_OPENING_STATE;
 527         newchannel->onchannel_callback = onchannelcallback;
 528         newchannel->channel_callback_context = context;
 529
 530         err = hv_ringbuffer_init(&newchannel->outbound, page, send_pages);
 531         if (err)
 532                 goto error_clean_ring;
 533
 534         err = hv_ringbuffer_init(&newchannel->inbound,
 535                                  &page[send_pages], recv_pages);
 536         if (err)
 537                 goto error_clean_ring;
 538
 539         /* Establish the gpadl for the ring buffer */
 540         newchannel->ringbuffer_gpadlhandle = 0;
 541
 542         err = __vmbus_establish_gpadl(newchannel, HV_GPADL_RING,
 543                                       page_address(newchannel->ringbuffer_page),
 544                                       (send_pages + recv_pages) << PAGE_SHIFT,
 545                                       newchannel->ringbuffer_send_offset << PAGE_SHIFT,
 546                                       &newchannel->ringbuffer_gpadlhandle);
 547         if (err)
 548                 goto error_clean_ring;
 549
 550         /* Create and init the channel open message */
 551         open_info = kmalloc(sizeof(*open_info) +
 552                            sizeof(struct vmbus_channel_open_channel),
 553                            GFP_KERNEL);
 554         if (!open_info) {
 555                 err = -ENOMEM;
 556                 goto error_free_gpadl;
 557         }
 558
 559         init_completion(&open_info->waitevent);
 560         open_info->waiting_channel = newchannel;
 561
 562         open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
 563         open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
 564         open_msg->openid = newchannel->offermsg.child_relid;
 565         open_msg->child_relid = newchannel->offermsg.child_relid;
 566         open_msg->ringbuffer_gpadlhandle = newchannel->ringbuffer_gpadlhandle;
 567         /*
 568          * The unit of ->downstream_ringbuffer_pageoffset is HV_HYP_PAGE and
 569          * the unit of ->ringbuffer_send_offset (i.e. send_pages) is PAGE, so
 570          * here we calculate it into HV_HYP_PAGE.
 571          */
 572         open_msg->downstream_ringbuffer_pageoffset =
 573                 hv_ring_gpadl_send_hvpgoffset(send_pages << PAGE_SHIFT);
 574         open_msg->target_vp = hv_cpu_number_to_vp_number(newchannel->target_cpu);
 575
 576         if (userdatalen)
 577                 memcpy(open_msg->userdata, userdata, userdatalen);
 578
 579         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 580         list_add_tail(&open_info->msglistentry,
 581                       &vmbus_connection.chn_msg_list);
 582         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 583
 584         if (newchannel->rescind) {
 585                 err = -ENODEV;
 586                 goto error_free_info;
 587         }
 588
 589         err = vmbus_post_msg(open_msg,
 590                              sizeof(struct vmbus_channel_open_channel), true);
 591
 592         trace_vmbus_open(open_msg, err);
 593
 594         if (err != 0)
 595                 goto error_clean_msglist;
 596
 597         wait_for_completion(&open_info->waitevent);
 598
 599         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 600         list_del(&open_info->msglistentry);
 601         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 602
 603         if (newchannel->rescind) {
 604                 err = -ENODEV;
 605                 goto error_free_info;
 606         }
 607
 608         if (open_info->response.open_result.status) {
 609                 err = -EAGAIN;
 610                 goto error_free_info;
 611         }
 612
 613         newchannel->state = CHANNEL_OPENED_STATE;
 614         kfree(open_info);
 615         return 0;
 616
 617 error_clean_msglist:
 618         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 619         list_del(&open_info->msglistentry);
 620         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 621 error_free_info:
 622         kfree(open_info);
 623 error_free_gpadl:
 624         vmbus_teardown_gpadl(newchannel, newchannel->ringbuffer_gpadlhandle);
 625         newchannel->ringbuffer_gpadlhandle = 0;
 626 error_clean_ring:
 627         hv_ringbuffer_cleanup(&newchannel->outbound);
 628         hv_ringbuffer_cleanup(&newchannel->inbound);
 629         newchannel->state = CHANNEL_OPEN_STATE;
 630         return err;
 631 }
 632
 633 /*
 634  * vmbus_connect_ring - Open the channel but reuse ring buffer
 635  */
 636 int vmbus_connect_ring(struct vmbus_channel *newchannel,
 637                        void (*onchannelcallback)(void *context), void *context)
 638 {
 639         return  __vmbus_open(newchannel, NULL, 0, onchannelcallback, context);
 640 }
 641 EXPORT_SYMBOL_GPL(vmbus_connect_ring);
 642
 643 /*
 644  * vmbus_open - Open the specified channel.
 645  */
 646 int vmbus_open(struct vmbus_channel *newchannel,
 647                u32 send_ringbuffer_size, u32 recv_ringbuffer_size,
 648                void *userdata, u32 userdatalen,
 649                void (*onchannelcallback)(void *context), void *context)
 650 {
 651         int err;
 652
 653         err = vmbus_alloc_ring(newchannel, send_ringbuffer_size,
 654                                recv_ringbuffer_size);
 655         if (err)
 656                 return err;
 657
 658         err = __vmbus_open(newchannel, userdata, userdatalen,
 659                            onchannelcallback, context);
 660         if (err)
 661                 vmbus_free_ring(newchannel);
 662
 663         return err;
 664 }
 665 EXPORT_SYMBOL_GPL(vmbus_open);
 666
 667 /*
 668  * vmbus_teardown_gpadl -Teardown the specified GPADL handle
 669  */
 670 int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle)
 671 {
 672         struct vmbus_channel_gpadl_teardown *msg;
 673         struct vmbus_channel_msginfo *info;
 674         unsigned long flags;
 675         int ret;
 676
 677         info = kmalloc(sizeof(*info) +
 678                        sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
 679         if (!info)
 680                 return -ENOMEM;
 681
 682         init_completion(&info->waitevent);
 683         info->waiting_channel = channel;
 684
 685         msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
 686
 687         msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
 688         msg->child_relid = channel->offermsg.child_relid;
 689         msg->gpadl = gpadl_handle;
 690
 691         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 692         list_add_tail(&info->msglistentry,
 693                       &vmbus_connection.chn_msg_list);
 694         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 695
 696         if (channel->rescind)
 697                 goto post_msg_err;
 698
 699         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_gpadl_teardown),
 700                              true);
 701
 702         trace_vmbus_teardown_gpadl(msg, ret);
 703
 704         if (ret)
 705                 goto post_msg_err;
 706
 707         wait_for_completion(&info->waitevent);
 708
 709 post_msg_err:
 710         /*
 711          * If the channel has been rescinded;
 712          * we will be awakened by the rescind
 713          * handler; set the error code to zero so we don't leak memory.
 714          */
 715         if (channel->rescind)
 716                 ret = 0;
 717
 718         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 719         list_del(&info->msglistentry);
 720         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 721
 722         kfree(info);
 723         return ret;
 724 }
 725 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
 726
 727 void vmbus_reset_channel_cb(struct vmbus_channel *channel)
 728 {
 729         unsigned long flags;
 730
 731         /*
 732          * vmbus_on_event(), running in the per-channel tasklet, can race
 733          * with vmbus_close_internal() in the case of SMP guest, e.g., when
 734          * the former is accessing channel->inbound.ring_buffer, the latter
 735          * could be freeing the ring_buffer pages, so here we must stop it
 736          * first.
 737          *
 738          * vmbus_chan_sched() might call the netvsc driver callback function
 739          * that ends up scheduling NAPI work that accesses the ring buffer.
 740          * At this point, we have to ensure that any such work is completed
 741          * and that the channel ring buffer is no longer being accessed, cf.
 742          * the calls to napi_disable() in netvsc_device_remove().
 743          */
 744         tasklet_disable(&channel->callback_event);
 745
 746         /* See the inline comments in vmbus_chan_sched(). */
 747         spin_lock_irqsave(&channel->sched_lock, flags);
 748         channel->onchannel_callback = NULL;
 749         spin_unlock_irqrestore(&channel->sched_lock, flags);
 750
 751         channel->sc_creation_callback = NULL;
 752
 753         /* Re-enable tasklet for use on re-open */
 754         tasklet_enable(&channel->callback_event);
 755 }
 756
 757 static int vmbus_close_internal(struct vmbus_channel *channel)
 758 {
 759         struct vmbus_channel_close_channel *msg;
 760         int ret;
 761
 762         vmbus_reset_channel_cb(channel);
 763
 764         /*
 765          * In case a device driver's probe() fails (e.g.,
 766          * util_probe() -> vmbus_open() returns -ENOMEM) and the device is
 767          * rescinded later (e.g., we dynamically disable an Integrated Service
 768          * in Hyper-V Manager), the driver's remove() invokes vmbus_close():
 769          * here we should skip most of the below cleanup work.
 770          */
 771         if (channel->state != CHANNEL_OPENED_STATE)
 772                 return -EINVAL;
 773
 774         channel->state = CHANNEL_OPEN_STATE;
 775
 776         /* Send a closing message */
 777
 778         msg = &channel->close_msg.msg;
 779
 780         msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
 781         msg->child_relid = channel->offermsg.child_relid;
 782
 783         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel),
 784                              true);
 785
 786         trace_vmbus_close_internal(msg, ret);
 787
 788         if (ret) {
 789                 pr_err("Close failed: close post msg return is %d\n", ret);
 790                 /*
 791                  * If we failed to post the close msg,
 792                  * it is perhaps better to leak memory.
 793                  */
 794         }
 795
 796         /* Tear down the gpadl for the channel's ring buffer */
 797         else if (channel->ringbuffer_gpadlhandle) {
 798                 ret = vmbus_teardown_gpadl(channel,
 799                                            channel->ringbuffer_gpadlhandle);
 800                 if (ret) {
 801                         pr_err("Close failed: teardown gpadl return %d\n", ret);
 802                         /*
 803                          * If we failed to teardown gpadl,
 804                          * it is perhaps better to leak memory.
 805                          */
 806                 }
 807
 808                 channel->ringbuffer_gpadlhandle = 0;
 809         }
 810
 811         return ret;
 812 }
 813
 814 /* disconnect ring - close all channels */
 815 int vmbus_disconnect_ring(struct vmbus_channel *channel)
 816 {
 817         struct vmbus_channel *cur_channel, *tmp;
 818         int ret;
 819
 820         if (channel->primary_channel != NULL)
 821                 return -EINVAL;
 822
 823         list_for_each_entry_safe(cur_channel, tmp, &channel->sc_list, sc_list) {
 824                 if (cur_channel->rescind)
 825                         wait_for_completion(&cur_channel->rescind_event);
 826
 827                 mutex_lock(&vmbus_connection.channel_mutex);
 828                 if (vmbus_close_internal(cur_channel) == 0) {
 829                         vmbus_free_ring(cur_channel);
 830
 831                         if (cur_channel->rescind)
 832                                 hv_process_channel_removal(cur_channel);
 833                 }
 834                 mutex_unlock(&vmbus_connection.channel_mutex);
 835         }
 836
 837         /*
 838          * Now close the primary.
 839          */
 840         mutex_lock(&vmbus_connection.channel_mutex);
 841         ret = vmbus_close_internal(channel);
 842         mutex_unlock(&vmbus_connection.channel_mutex);
 843
 844         return ret;
 845 }
 846 EXPORT_SYMBOL_GPL(vmbus_disconnect_ring);
 847
 848 /*
 849  * vmbus_close - Close the specified channel
 850  */
 851 void vmbus_close(struct vmbus_channel *channel)
 852 {
 853         if (vmbus_disconnect_ring(channel) == 0)
 854                 vmbus_free_ring(channel);
 855 }
 856 EXPORT_SYMBOL_GPL(vmbus_close);
 857
 858 /**
 859  * vmbus_sendpacket() - Send the specified buffer on the given channel
 860  * @channel: Pointer to vmbus_channel structure
 861  * @buffer: Pointer to the buffer you want to send the data from.
 862  * @bufferlen: Maximum size of what the buffer holds.
 863  * @requestid: Identifier of the request
 864  * @type: Type of packet that is being sent e.g. negotiate, time
 865  *        packet etc.
 866  * @flags: 0 or VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED
 867  *
 868  * Sends data in @buffer directly to Hyper-V via the vmbus.
 869  * This will send the data unparsed to Hyper-V.
 870  *
 871  * Mainly used by Hyper-V drivers.
 872  */
 873 int vmbus_sendpacket(struct vmbus_channel *channel, void *buffer,
 874                            u32 bufferlen, u64 requestid,
 875                            enum vmbus_packet_type type, u32 flags)
 876 {
 877         struct vmpacket_descriptor desc;
 878         u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
 879         u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 880         struct kvec bufferlist[3];
 881         u64 aligned_data = 0;
 882         int num_vecs = ((bufferlen != 0) ? 3 : 1);
 883
 884
 885         /* Setup the descriptor */
 886         desc.type = type; /* VmbusPacketTypeDataInBand; */
 887         desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
 888         /* in 8-bytes granularity */
 889         desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3;
 890         desc.len8 = (u16)(packetlen_aligned >> 3);
 891         desc.trans_id = requestid;
 892
 893         bufferlist[0].iov_base = &desc;
 894         bufferlist[0].iov_len = sizeof(struct vmpacket_descriptor);
 895         bufferlist[1].iov_base = buffer;
 896         bufferlist[1].iov_len = bufferlen;
 897         bufferlist[2].iov_base = &aligned_data;
 898         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 899
 900         return hv_ringbuffer_write(channel, bufferlist, num_vecs);
 901 }
 902 EXPORT_SYMBOL(vmbus_sendpacket);
 903
 904 /*
 905  * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
 906  * packets using a GPADL Direct packet type. This interface allows you
 907  * to control notifying the host. This will be useful for sending
 908  * batched data. Also the sender can control the send flags
 909  * explicitly.
 910  */
 911 int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
 912                                 struct hv_page_buffer pagebuffers[],
 913                                 u32 pagecount, void *buffer, u32 bufferlen,
 914                                 u64 requestid)
 915 {
 916         int i;
 917         struct vmbus_channel_packet_page_buffer desc;
 918         u32 descsize;
 919         u32 packetlen;
 920         u32 packetlen_aligned;
 921         struct kvec bufferlist[3];
 922         u64 aligned_data = 0;
 923
 924         if (pagecount > MAX_PAGE_BUFFER_COUNT)
 925                 return -EINVAL;
 926
 927         /*
 928          * Adjust the size down since vmbus_channel_packet_page_buffer is the
 929          * largest size we support
 930          */
 931         descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
 932                           ((MAX_PAGE_BUFFER_COUNT - pagecount) *
 933                           sizeof(struct hv_page_buffer));
 934         packetlen = descsize + bufferlen;
 935         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 936
 937         /* Setup the descriptor */
 938         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
 939         desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 940         desc.dataoffset8 = descsize >> 3; /* in 8-bytes granularity */
 941         desc.length8 = (u16)(packetlen_aligned >> 3);
 942         desc.transactionid = requestid;
 943         desc.reserved = 0;
 944         desc.rangecount = pagecount;
 945
 946         for (i = 0; i < pagecount; i++) {
 947                 desc.range[i].len = pagebuffers[i].len;
 948                 desc.range[i].offset = pagebuffers[i].offset;
 949                 desc.range[i].pfn        = pagebuffers[i].pfn;
 950         }
 951
 952         bufferlist[0].iov_base = &desc;
 953         bufferlist[0].iov_len = descsize;
 954         bufferlist[1].iov_base = buffer;
 955         bufferlist[1].iov_len = bufferlen;
 956         bufferlist[2].iov_base = &aligned_data;
 957         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 958
 959         return hv_ringbuffer_write(channel, bufferlist, 3);
 960 }
 961 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
 962
 963 /*
 964  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
 965  * using a GPADL Direct packet type.
 966  * The buffer includes the vmbus descriptor.
 967  */
 968 int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
 969                               struct vmbus_packet_mpb_array *desc,
 970                               u32 desc_size,
 971                               void *buffer, u32 bufferlen, u64 requestid)
 972 {
 973         u32 packetlen;
 974         u32 packetlen_aligned;
 975         struct kvec bufferlist[3];
 976         u64 aligned_data = 0;
 977
 978         packetlen = desc_size + bufferlen;
 979         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
 980
 981         /* Setup the descriptor */
 982         desc->type = VM_PKT_DATA_USING_GPA_DIRECT;
 983         desc->flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
 984         desc->dataoffset8 = desc_size >> 3; /* in 8-bytes granularity */
 985         desc->length8 = (u16)(packetlen_aligned >> 3);
 986         desc->transactionid = requestid;
 987         desc->reserved = 0;
 988         desc->rangecount = 1;
 989
 990         bufferlist[0].iov_base = desc;
 991         bufferlist[0].iov_len = desc_size;
 992         bufferlist[1].iov_base = buffer;
 993         bufferlist[1].iov_len = bufferlen;
 994         bufferlist[2].iov_base = &aligned_data;
 995         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
 996
 997         return hv_ringbuffer_write(channel, bufferlist, 3);
 998 }
 999 EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc);
1000
1001 /**
1002  * __vmbus_recvpacket() - Retrieve the user packet on the specified channel
1003  * @channel: Pointer to vmbus_channel structure
1004  * @buffer: Pointer to the buffer you want to receive the data into.
1005  * @bufferlen: Maximum size of what the buffer can hold.
1006  * @buffer_actual_len: The actual size of the data after it was received.
1007  * @requestid: Identifier of the request
1008  * @raw: true means keep the vmpacket_descriptor header in the received data.
1009  *
1010  * Receives directly from the hyper-v vmbus and puts the data it received
1011  * into Buffer. This will receive the data unparsed from hyper-v.
1012  *
1013  * Mainly used by Hyper-V drivers.
1014  */
1015 static inline int
1016 __vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
1017                    u32 bufferlen, u32 *buffer_actual_len, u64 *requestid,
1018                    bool raw)
1019 {
1020         return hv_ringbuffer_read(channel, buffer, bufferlen,
1021                                   buffer_actual_len, requestid, raw);
1022
1023 }
1024
1025 int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
1026                      u32 bufferlen, u32 *buffer_actual_len,
1027                      u64 *requestid)
1028 {
1029         return __vmbus_recvpacket(channel, buffer, bufferlen,
1030                                   buffer_actual_len, requestid, false);
1031 }
1032 EXPORT_SYMBOL(vmbus_recvpacket);
1033
1034 /*
1035  * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
1036  */
1037 int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
1038                               u32 bufferlen, u32 *buffer_actual_len,
1039                               u64 *requestid)
1040 {
1041         return __vmbus_recvpacket(channel, buffer, bufferlen,
1042                                   buffer_actual_len, requestid, true);
1043 }
1044 EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);