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 <linux/set_memory.h>
  21 #include <asm/page.h>
  22 #include <asm/mshyperv.h>
  23
  24 #include "hyperv_vmbus.h"
  25
  26 /*
  27  * hv_gpadl_size - Return the real size of a gpadl, the size that Hyper-V uses
  28  *
  29  * For BUFFER gpadl, Hyper-V uses the exact same size as the guest does.
  30  *
  31  * For RING gpadl, in each ring, the guest uses one PAGE_SIZE as the header
  32  * (because of the alignment requirement), however, the hypervisor only
  33  * uses the first HV_HYP_PAGE_SIZE as the header, therefore leaving a
  34  * (PAGE_SIZE - HV_HYP_PAGE_SIZE) gap. And since there are two rings in a
  35  * ringbuffer, the total size for a RING gpadl that Hyper-V uses is the
  36  * total size that the guest uses minus twice of the gap size.
  37  */
  38 static inline u32 hv_gpadl_size(enum hv_gpadl_type type, u32 size)
  39 {
  40         switch (type) {
  41         case HV_GPADL_BUFFER:
  42                 return size;
  43         case HV_GPADL_RING:
  44                 /* The size of a ringbuffer must be page-aligned */
  45                 BUG_ON(size % PAGE_SIZE);
  46                 /*
  47                  * Two things to notice here:
  48                  * 1) We're processing two ring buffers as a unit
  49                  * 2) We're skipping any space larger than HV_HYP_PAGE_SIZE in
  50                  * the first guest-size page of each of the two ring buffers.
  51                  * So we effectively subtract out two guest-size pages, and add
  52                  * back two Hyper-V size pages.
  53                  */
  54                 return size - 2 * (PAGE_SIZE - HV_HYP_PAGE_SIZE);
  55         }
  56         BUG();
  57         return 0;
  58 }
  59
  60 /*
  61  * hv_ring_gpadl_send_hvpgoffset - Calculate the send offset (in unit of
  62  *                                 HV_HYP_PAGE) in a ring gpadl based on the
  63  *                                 offset in the guest
  64  *
  65  * @offset: the offset (in bytes) where the send ringbuffer starts in the
  66  *               virtual address space of the guest
  67  */
  68 static inline u32 hv_ring_gpadl_send_hvpgoffset(u32 offset)
  69 {
  70
  71         /*
  72          * For RING gpadl, in each ring, the guest uses one PAGE_SIZE as the
  73          * header (because of the alignment requirement), however, the
  74          * hypervisor only uses the first HV_HYP_PAGE_SIZE as the header,
  75          * therefore leaving a (PAGE_SIZE - HV_HYP_PAGE_SIZE) gap.
  76          *
  77          * And to calculate the effective send offset in gpadl, we need to
  78          * substract this gap.
  79          */
  80         return (offset - (PAGE_SIZE - HV_HYP_PAGE_SIZE)) >> HV_HYP_PAGE_SHIFT;
  81 }
  82
  83 /*
  84  * hv_gpadl_hvpfn - Return the Hyper-V page PFN of the @i th Hyper-V page in
  85  *                  the gpadl
  86  *
  87  * @type: the type of the gpadl
  88  * @kbuffer: the pointer to the gpadl in the guest
  89  * @size: the total size (in bytes) of the gpadl
  90  * @send_offset: the offset (in bytes) where the send ringbuffer starts in the
  91  *               virtual address space of the guest
  92  * @i: the index
  93  */
  94 static inline u64 hv_gpadl_hvpfn(enum hv_gpadl_type type, void *kbuffer,
  95                                  u32 size, u32 send_offset, int i)
  96 {
  97         int send_idx = hv_ring_gpadl_send_hvpgoffset(send_offset);
  98         unsigned long delta = 0UL;
  99
 100         switch (type) {
 101         case HV_GPADL_BUFFER:
 102                 break;
 103         case HV_GPADL_RING:
 104                 if (i == 0)
 105                         delta = 0;
 106                 else if (i <= send_idx)
 107                         delta = PAGE_SIZE - HV_HYP_PAGE_SIZE;
 108                 else
 109                         delta = 2 * (PAGE_SIZE - HV_HYP_PAGE_SIZE);
 110                 break;
 111         default:
 112                 BUG();
 113                 break;
 114         }
 115
 116         return virt_to_hvpfn(kbuffer + delta + (HV_HYP_PAGE_SIZE * i));
 117 }
 118
 119 /*
 120  * vmbus_setevent- Trigger an event notification on the specified
 121  * channel.
 122  */
 123 void vmbus_setevent(struct vmbus_channel *channel)
 124 {
 125         struct hv_monitor_page *monitorpage;
 126
 127         trace_vmbus_setevent(channel);
 128
 129         /*
 130          * For channels marked as in "low latency" mode
 131          * bypass the monitor page mechanism.
 132          */
 133         if (channel->offermsg.monitor_allocated && !channel->low_latency) {
 134                 vmbus_send_interrupt(channel->offermsg.child_relid);
 135
 136                 /* Get the child to parent monitor page */
 137                 monitorpage = vmbus_connection.monitor_pages[1];
 138
 139                 sync_set_bit(channel->monitor_bit,
 140                         (unsigned long *)&monitorpage->trigger_group
 141                                         [channel->monitor_grp].pending);
 142
 143         } else {
 144                 vmbus_set_event(channel);
 145         }
 146 }
 147 EXPORT_SYMBOL_GPL(vmbus_setevent);
 148
 149 /* vmbus_free_ring - drop mapping of ring buffer */
 150 void vmbus_free_ring(struct vmbus_channel *channel)
 151 {
 152         hv_ringbuffer_cleanup(&channel->outbound);
 153         hv_ringbuffer_cleanup(&channel->inbound);
 154
 155         if (channel->ringbuffer_page) {
 156                 __free_pages(channel->ringbuffer_page,
 157                              get_order(channel->ringbuffer_pagecount
 158                                        << PAGE_SHIFT));
 159                 channel->ringbuffer_page = NULL;
 160         }
 161 }
 162 EXPORT_SYMBOL_GPL(vmbus_free_ring);
 163
 164 /* vmbus_alloc_ring - allocate and map pages for ring buffer */
 165 int vmbus_alloc_ring(struct vmbus_channel *newchannel,
 166                      u32 send_size, u32 recv_size)
 167 {
 168         struct page *page;
 169         int order;
 170
 171         if (send_size % PAGE_SIZE || recv_size % PAGE_SIZE)
 172                 return -EINVAL;
 173
 174         /* Allocate the ring buffer */
 175         order = get_order(send_size + recv_size);
 176         page = alloc_pages_node(cpu_to_node(newchannel->target_cpu),
 177                                 GFP_KERNEL|__GFP_ZERO, order);
 178
 179         if (!page)
 180                 page = alloc_pages(GFP_KERNEL|__GFP_ZERO, order);
 181
 182         if (!page)
 183                 return -ENOMEM;
 184
 185         newchannel->ringbuffer_page = page;
 186         newchannel->ringbuffer_pagecount = (send_size + recv_size) >> PAGE_SHIFT;
 187         newchannel->ringbuffer_send_offset = send_size >> PAGE_SHIFT;
 188
 189         return 0;
 190 }
 191 EXPORT_SYMBOL_GPL(vmbus_alloc_ring);
 192
 193 /* Used for Hyper-V Socket: a guest client's connect() to the host */
 194 int vmbus_send_tl_connect_request(const guid_t *shv_guest_servie_id,
 195                                   const guid_t *shv_host_servie_id)
 196 {
 197         struct vmbus_channel_tl_connect_request conn_msg;
 198         int ret;
 199
 200         memset(&conn_msg, 0, sizeof(conn_msg));
 201         conn_msg.header.msgtype = CHANNELMSG_TL_CONNECT_REQUEST;
 202         conn_msg.guest_endpoint_id = *shv_guest_servie_id;
 203         conn_msg.host_service_id = *shv_host_servie_id;
 204
 205         ret = vmbus_post_msg(&conn_msg, sizeof(conn_msg), true);
 206
 207         trace_vmbus_send_tl_connect_request(&conn_msg, ret);
 208
 209         return ret;
 210 }
 211 EXPORT_SYMBOL_GPL(vmbus_send_tl_connect_request);
 212
 213 static int send_modifychannel_without_ack(struct vmbus_channel *channel, u32 target_vp)
 214 {
 215         struct vmbus_channel_modifychannel msg;
 216         int ret;
 217
 218         memset(&msg, 0, sizeof(msg));
 219         msg.header.msgtype = CHANNELMSG_MODIFYCHANNEL;
 220         msg.child_relid = channel->offermsg.child_relid;
 221         msg.target_vp = target_vp;
 222
 223         ret = vmbus_post_msg(&msg, sizeof(msg), true);
 224         trace_vmbus_send_modifychannel(&msg, ret);
 225
 226         return ret;
 227 }
 228
 229 static int send_modifychannel_with_ack(struct vmbus_channel *channel, u32 target_vp)
 230 {
 231         struct vmbus_channel_modifychannel *msg;
 232         struct vmbus_channel_msginfo *info;
 233         unsigned long flags;
 234         int ret;
 235
 236         info = kzalloc(sizeof(struct vmbus_channel_msginfo) +
 237                                 sizeof(struct vmbus_channel_modifychannel),
 238                        GFP_KERNEL);
 239         if (!info)
 240                 return -ENOMEM;
 241
 242         init_completion(&info->waitevent);
 243         info->waiting_channel = channel;
 244
 245         msg = (struct vmbus_channel_modifychannel *)info->msg;
 246         msg->header.msgtype = CHANNELMSG_MODIFYCHANNEL;
 247         msg->child_relid = channel->offermsg.child_relid;
 248         msg->target_vp = target_vp;
 249
 250         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 251         list_add_tail(&info->msglistentry, &vmbus_connection.chn_msg_list);
 252         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 253
 254         ret = vmbus_post_msg(msg, sizeof(*msg), true);
 255         trace_vmbus_send_modifychannel(msg, ret);
 256         if (ret != 0) {
 257                 spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 258                 list_del(&info->msglistentry);
 259                 spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 260                 goto free_info;
 261         }
 262
 263         /*
 264          * Release channel_mutex; otherwise, vmbus_onoffer_rescind() could block on
 265          * the mutex and be unable to signal the completion.
 266          *
 267          * See the caller target_cpu_store() for information about the usage of the
 268          * mutex.
 269          */
 270         mutex_unlock(&vmbus_connection.channel_mutex);
 271         wait_for_completion(&info->waitevent);
 272         mutex_lock(&vmbus_connection.channel_mutex);
 273
 274         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 275         list_del(&info->msglistentry);
 276         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 277
 278         if (info->response.modify_response.status)
 279                 ret = -EAGAIN;
 280
 281 free_info:
 282         kfree(info);
 283         return ret;
 284 }
 285
 286 /*
 287  * Set/change the vCPU (@target_vp) the channel (@child_relid) will interrupt.
 288  *
 289  * CHANNELMSG_MODIFYCHANNEL messages are aynchronous.  When VMbus version 5.3
 290  * or later is negotiated, Hyper-V always sends an ACK in response to such a
 291  * message.  For VMbus version 5.2 and earlier, it never sends an ACK.  With-
 292  * out an ACK, we can not know when the host will stop interrupting the "old"
 293  * vCPU and start interrupting the "new" vCPU for the given channel.
 294  *
 295  * The CHANNELMSG_MODIFYCHANNEL message type is supported since VMBus version
 296  * VERSION_WIN10_V4_1.
 297  */
 298 int vmbus_send_modifychannel(struct vmbus_channel *channel, u32 target_vp)
 299 {
 300         if (vmbus_proto_version >= VERSION_WIN10_V5_3)
 301                 return send_modifychannel_with_ack(channel, target_vp);
 302         return send_modifychannel_without_ack(channel, target_vp);
 303 }
 304 EXPORT_SYMBOL_GPL(vmbus_send_modifychannel);
 305
 306 /*
 307  * create_gpadl_header - Creates a gpadl for the specified buffer
 308  */
 309 static int create_gpadl_header(enum hv_gpadl_type type, void *kbuffer,
 310                                u32 size, u32 send_offset,
 311                                struct vmbus_channel_msginfo **msginfo)
 312 {
 313         int i;
 314         int pagecount;
 315         struct vmbus_channel_gpadl_header *gpadl_header;
 316         struct vmbus_channel_gpadl_body *gpadl_body;
 317         struct vmbus_channel_msginfo *msgheader;
 318         struct vmbus_channel_msginfo *msgbody = NULL;
 319         u32 msgsize;
 320
 321         int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
 322
 323         pagecount = hv_gpadl_size(type, size) >> HV_HYP_PAGE_SHIFT;
 324
 325         pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 326                   sizeof(struct vmbus_channel_gpadl_header) -
 327                   sizeof(struct gpa_range);
 328         pfncount = umin(pagecount, pfnsize / sizeof(u64));
 329
 330         msgsize = sizeof(struct vmbus_channel_msginfo) +
 331                   sizeof(struct vmbus_channel_gpadl_header) +
 332                   sizeof(struct gpa_range) + pfncount * sizeof(u64);
 333         msgheader =  kzalloc(msgsize, GFP_KERNEL);
 334         if (!msgheader)
 335                 return -ENOMEM;
 336
 337         INIT_LIST_HEAD(&msgheader->submsglist);
 338         msgheader->msgsize = msgsize;
 339
 340         gpadl_header = (struct vmbus_channel_gpadl_header *)
 341                 msgheader->msg;
 342         gpadl_header->rangecount = 1;
 343         gpadl_header->range_buflen = sizeof(struct gpa_range) +
 344                                  pagecount * sizeof(u64);
 345         gpadl_header->range[0].byte_offset = 0;
 346         gpadl_header->range[0].byte_count = hv_gpadl_size(type, size);
 347         for (i = 0; i < pfncount; i++)
 348                 gpadl_header->range[0].pfn_array[i] = hv_gpadl_hvpfn(
 349                         type, kbuffer, size, send_offset, i);
 350         *msginfo = msgheader;
 351
 352         pfnsum = pfncount;
 353         pfnleft = pagecount - pfncount;
 354
 355         /* how many pfns can we fit in a body message */
 356         pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
 357                   sizeof(struct vmbus_channel_gpadl_body);
 358         pfncount = pfnsize / sizeof(u64);
 359
 360         /*
 361          * If pfnleft is zero, everything fits in the header and no body
 362          * messages are needed
 363          */
 364         while (pfnleft) {
 365                 pfncurr = umin(pfncount, pfnleft);
 366                 msgsize = sizeof(struct vmbus_channel_msginfo) +
 367                           sizeof(struct vmbus_channel_gpadl_body) +
 368                           pfncurr * sizeof(u64);
 369                 msgbody = kzalloc(msgsize, GFP_KERNEL);
 370
 371                 if (!msgbody) {
 372                         struct vmbus_channel_msginfo *pos = NULL;
 373                         struct vmbus_channel_msginfo *tmp = NULL;
 374                         /*
 375                          * Free up all the allocated messages.
 376                          */
 377                         list_for_each_entry_safe(pos, tmp,
 378                                 &msgheader->submsglist,
 379                                 msglistentry) {
 380
 381                                 list_del(&pos->msglistentry);
 382                                 kfree(pos);
 383                         }
 384                         kfree(msgheader);
 385                         return -ENOMEM;
 386                 }
 387
 388                 msgbody->msgsize = msgsize;
 389                 gpadl_body = (struct vmbus_channel_gpadl_body *)msgbody->msg;
 390
 391                 /*
 392                  * Gpadl is u32 and we are using a pointer which could
 393                  * be 64-bit
 394                  * This is governed by the guest/host protocol and
 395                  * so the hypervisor guarantees that this is ok.
 396                  */
 397                 for (i = 0; i < pfncurr; i++)
 398                         gpadl_body->pfn[i] = hv_gpadl_hvpfn(type,
 399                                 kbuffer, size, send_offset, pfnsum + i);
 400
 401                 /* add to msg header */
 402                 list_add_tail(&msgbody->msglistentry, &msgheader->submsglist);
 403                 pfnsum += pfncurr;
 404                 pfnleft -= pfncurr;
 405         }
 406
 407         return 0;
 408 }
 409
 410 /*
 411  * __vmbus_establish_gpadl - Establish a GPADL for a buffer or ringbuffer
 412  *
 413  * @channel: a channel
 414  * @type: the type of the corresponding GPADL, only meaningful for the guest.
 415  * @kbuffer: from kmalloc or vmalloc
 416  * @size: page-size multiple
 417  * @send_offset: the offset (in bytes) where the send ring buffer starts,
 418  *              should be 0 for BUFFER type gpadl
 419  * @gpadl_handle: some funky thing
 420  */
 421 static int __vmbus_establish_gpadl(struct vmbus_channel *channel,
 422                                    enum hv_gpadl_type type, void *kbuffer,
 423                                    u32 size, u32 send_offset,
 424                                    struct vmbus_gpadl *gpadl)
 425 {
 426         struct vmbus_channel_gpadl_header *gpadlmsg;
 427         struct vmbus_channel_gpadl_body *gpadl_body;
 428         struct vmbus_channel_msginfo *msginfo = NULL;
 429         struct vmbus_channel_msginfo *submsginfo, *tmp;
 430         struct list_head *curr;
 431         u32 next_gpadl_handle;
 432         unsigned long flags;
 433         int ret = 0;
 434
 435         next_gpadl_handle =
 436                 (atomic_inc_return(&vmbus_connection.next_gpadl_handle) - 1);
 437
 438         ret = create_gpadl_header(type, kbuffer, size, send_offset, &msginfo);
 439         if (ret)
 440                 return ret;
 441
 442         ret = set_memory_decrypted((unsigned long)kbuffer,
 443                                    PFN_UP(size));
 444         if (ret) {
 445                 dev_warn(&channel->device_obj->device,
 446                          "Failed to set host visibility for new GPADL %d.\n",
 447                          ret);
 448                 return ret;
 449         }
 450
 451         init_completion(&msginfo->waitevent);
 452         msginfo->waiting_channel = channel;
 453
 454         gpadlmsg = (struct vmbus_channel_gpadl_header *)msginfo->msg;
 455         gpadlmsg->header.msgtype = CHANNELMSG_GPADL_HEADER;
 456         gpadlmsg->child_relid = channel->offermsg.child_relid;
 457         gpadlmsg->gpadl = next_gpadl_handle;
 458
 459
 460         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 461         list_add_tail(&msginfo->msglistentry,
 462                       &vmbus_connection.chn_msg_list);
 463
 464         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 465
 466         if (channel->rescind) {
 467                 ret = -ENODEV;
 468                 goto cleanup;
 469         }
 470
 471         ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize -
 472                              sizeof(*msginfo), true);
 473
 474         trace_vmbus_establish_gpadl_header(gpadlmsg, ret);
 475
 476         if (ret != 0)
 477                 goto cleanup;
 478
 479         list_for_each(curr, &msginfo->submsglist) {
 480                 submsginfo = (struct vmbus_channel_msginfo *)curr;
 481                 gpadl_body =
 482                         (struct vmbus_channel_gpadl_body *)submsginfo->msg;
 483
 484                 gpadl_body->header.msgtype =
 485                         CHANNELMSG_GPADL_BODY;
 486                 gpadl_body->gpadl = next_gpadl_handle;
 487
 488                 ret = vmbus_post_msg(gpadl_body,
 489                                      submsginfo->msgsize - sizeof(*submsginfo),
 490                                      true);
 491
 492                 trace_vmbus_establish_gpadl_body(gpadl_body, ret);
 493
 494                 if (ret != 0)
 495                         goto cleanup;
 496
 497         }
 498         wait_for_completion(&msginfo->waitevent);
 499
 500         if (msginfo->response.gpadl_created.creation_status != 0) {
 501                 pr_err("Failed to establish GPADL: err = 0x%x\n",
 502                        msginfo->response.gpadl_created.creation_status);
 503
 504                 ret = -EDQUOT;
 505                 goto cleanup;
 506         }
 507
 508         if (channel->rescind) {
 509                 ret = -ENODEV;
 510                 goto cleanup;
 511         }
 512
 513         /* At this point, we received the gpadl created msg */
 514         gpadl->gpadl_handle = gpadlmsg->gpadl;
 515         gpadl->buffer = kbuffer;
 516         gpadl->size = size;
 517
 518
 519 cleanup:
 520         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 521         list_del(&msginfo->msglistentry);
 522         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 523         list_for_each_entry_safe(submsginfo, tmp, &msginfo->submsglist,
 524                                  msglistentry) {
 525                 kfree(submsginfo);
 526         }
 527
 528         kfree(msginfo);
 529
 530         if (ret)
 531                 set_memory_encrypted((unsigned long)kbuffer,
 532                                      PFN_UP(size));
 533
 534         return ret;
 535 }
 536
 537 /*
 538  * vmbus_establish_gpadl - Establish a GPADL for the specified buffer
 539  *
 540  * @channel: a channel
 541  * @kbuffer: from kmalloc or vmalloc
 542  * @size: page-size multiple
 543  * @gpadl_handle: some funky thing
 544  */
 545 int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
 546                           u32 size, struct vmbus_gpadl *gpadl)
 547 {
 548         return __vmbus_establish_gpadl(channel, HV_GPADL_BUFFER, kbuffer, size,
 549                                        0U, gpadl);
 550 }
 551 EXPORT_SYMBOL_GPL(vmbus_establish_gpadl);
 552
 553 /**
 554  * request_arr_init - Allocates memory for the requestor array. Each slot
 555  * keeps track of the next available slot in the array. Initially, each
 556  * slot points to the next one (as in a Linked List). The last slot
 557  * does not point to anything, so its value is U64_MAX by default.
 558  * @size The size of the array
 559  */
 560 static u64 *request_arr_init(u32 size)
 561 {
 562         int i;
 563         u64 *req_arr;
 564
 565         req_arr = kcalloc(size, sizeof(u64), GFP_KERNEL);
 566         if (!req_arr)
 567                 return NULL;
 568
 569         for (i = 0; i < size - 1; i++)
 570                 req_arr[i] = i + 1;
 571
 572         /* Last slot (no more available slots) */
 573         req_arr[i] = U64_MAX;
 574
 575         return req_arr;
 576 }
 577
 578 /*
 579  * vmbus_alloc_requestor - Initializes @rqstor's fields.
 580  * Index 0 is the first free slot
 581  * @size: Size of the requestor array
 582  */
 583 static int vmbus_alloc_requestor(struct vmbus_requestor *rqstor, u32 size)
 584 {
 585         u64 *rqst_arr;
 586         unsigned long *bitmap;
 587
 588         rqst_arr = request_arr_init(size);
 589         if (!rqst_arr)
 590                 return -ENOMEM;
 591
 592         bitmap = bitmap_zalloc(size, GFP_KERNEL);
 593         if (!bitmap) {
 594                 kfree(rqst_arr);
 595                 return -ENOMEM;
 596         }
 597
 598         rqstor->req_arr = rqst_arr;
 599         rqstor->req_bitmap = bitmap;
 600         rqstor->size = size;
 601         rqstor->next_request_id = 0;
 602         spin_lock_init(&rqstor->req_lock);
 603
 604         return 0;
 605 }
 606
 607 /*
 608  * vmbus_free_requestor - Frees memory allocated for @rqstor
 609  * @rqstor: Pointer to the requestor struct
 610  */
 611 static void vmbus_free_requestor(struct vmbus_requestor *rqstor)
 612 {
 613         kfree(rqstor->req_arr);
 614         bitmap_free(rqstor->req_bitmap);
 615 }
 616
 617 static int __vmbus_open(struct vmbus_channel *newchannel,
 618                        void *userdata, u32 userdatalen,
 619                        void (*onchannelcallback)(void *context), void *context)
 620 {
 621         struct vmbus_channel_open_channel *open_msg;
 622         struct vmbus_channel_msginfo *open_info = NULL;
 623         struct page *page = newchannel->ringbuffer_page;
 624         u32 send_pages, recv_pages;
 625         unsigned long flags;
 626         int err;
 627
 628         if (userdatalen > MAX_USER_DEFINED_BYTES)
 629                 return -EINVAL;
 630
 631         send_pages = newchannel->ringbuffer_send_offset;
 632         recv_pages = newchannel->ringbuffer_pagecount - send_pages;
 633
 634         if (newchannel->state != CHANNEL_OPEN_STATE)
 635                 return -EINVAL;
 636
 637         /* Create and init requestor */
 638         if (newchannel->rqstor_size) {
 639                 if (vmbus_alloc_requestor(&newchannel->requestor, newchannel->rqstor_size))
 640                         return -ENOMEM;
 641         }
 642
 643         newchannel->state = CHANNEL_OPENING_STATE;
 644         newchannel->onchannel_callback = onchannelcallback;
 645         newchannel->channel_callback_context = context;
 646
 647         if (!newchannel->max_pkt_size)
 648                 newchannel->max_pkt_size = VMBUS_DEFAULT_MAX_PKT_SIZE;
 649
 650         /* Establish the gpadl for the ring buffer */
 651         newchannel->ringbuffer_gpadlhandle.gpadl_handle = 0;
 652
 653         err = __vmbus_establish_gpadl(newchannel, HV_GPADL_RING,
 654                                       page_address(newchannel->ringbuffer_page),
 655                                       (send_pages + recv_pages) << PAGE_SHIFT,
 656                                       newchannel->ringbuffer_send_offset << PAGE_SHIFT,
 657                                       &newchannel->ringbuffer_gpadlhandle);
 658         if (err)
 659                 goto error_clean_ring;
 660
 661         err = hv_ringbuffer_init(&newchannel->outbound,
 662                                  page, send_pages, 0);
 663         if (err)
 664                 goto error_free_gpadl;
 665
 666         err = hv_ringbuffer_init(&newchannel->inbound, &page[send_pages],
 667                                  recv_pages, newchannel->max_pkt_size);
 668         if (err)
 669                 goto error_free_gpadl;
 670
 671         /* Create and init the channel open message */
 672         open_info = kzalloc(sizeof(*open_info) +
 673                            sizeof(struct vmbus_channel_open_channel),
 674                            GFP_KERNEL);
 675         if (!open_info) {
 676                 err = -ENOMEM;
 677                 goto error_free_gpadl;
 678         }
 679
 680         init_completion(&open_info->waitevent);
 681         open_info->waiting_channel = newchannel;
 682
 683         open_msg = (struct vmbus_channel_open_channel *)open_info->msg;
 684         open_msg->header.msgtype = CHANNELMSG_OPENCHANNEL;
 685         open_msg->openid = newchannel->offermsg.child_relid;
 686         open_msg->child_relid = newchannel->offermsg.child_relid;
 687         open_msg->ringbuffer_gpadlhandle
 688                 = newchannel->ringbuffer_gpadlhandle.gpadl_handle;
 689         /*
 690          * The unit of ->downstream_ringbuffer_pageoffset is HV_HYP_PAGE and
 691          * the unit of ->ringbuffer_send_offset (i.e. send_pages) is PAGE, so
 692          * here we calculate it into HV_HYP_PAGE.
 693          */
 694         open_msg->downstream_ringbuffer_pageoffset =
 695                 hv_ring_gpadl_send_hvpgoffset(send_pages << PAGE_SHIFT);
 696         open_msg->target_vp = hv_cpu_number_to_vp_number(newchannel->target_cpu);
 697
 698         if (userdatalen)
 699                 memcpy(open_msg->userdata, userdata, userdatalen);
 700
 701         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 702         list_add_tail(&open_info->msglistentry,
 703                       &vmbus_connection.chn_msg_list);
 704         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 705
 706         if (newchannel->rescind) {
 707                 err = -ENODEV;
 708                 goto error_clean_msglist;
 709         }
 710
 711         err = vmbus_post_msg(open_msg,
 712                              sizeof(struct vmbus_channel_open_channel), true);
 713
 714         trace_vmbus_open(open_msg, err);
 715
 716         if (err != 0)
 717                 goto error_clean_msglist;
 718
 719         wait_for_completion(&open_info->waitevent);
 720
 721         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 722         list_del(&open_info->msglistentry);
 723         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 724
 725         if (newchannel->rescind) {
 726                 err = -ENODEV;
 727                 goto error_free_info;
 728         }
 729
 730         if (open_info->response.open_result.status) {
 731                 err = -EAGAIN;
 732                 goto error_free_info;
 733         }
 734
 735         newchannel->state = CHANNEL_OPENED_STATE;
 736         kfree(open_info);
 737         return 0;
 738
 739 error_clean_msglist:
 740         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 741         list_del(&open_info->msglistentry);
 742         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 743 error_free_info:
 744         kfree(open_info);
 745 error_free_gpadl:
 746         vmbus_teardown_gpadl(newchannel, &newchannel->ringbuffer_gpadlhandle);
 747 error_clean_ring:
 748         hv_ringbuffer_cleanup(&newchannel->outbound);
 749         hv_ringbuffer_cleanup(&newchannel->inbound);
 750         vmbus_free_requestor(&newchannel->requestor);
 751         newchannel->state = CHANNEL_OPEN_STATE;
 752         return err;
 753 }
 754
 755 /*
 756  * vmbus_connect_ring - Open the channel but reuse ring buffer
 757  */
 758 int vmbus_connect_ring(struct vmbus_channel *newchannel,
 759                        void (*onchannelcallback)(void *context), void *context)
 760 {
 761         return  __vmbus_open(newchannel, NULL, 0, onchannelcallback, context);
 762 }
 763 EXPORT_SYMBOL_GPL(vmbus_connect_ring);
 764
 765 /*
 766  * vmbus_open - Open the specified channel.
 767  */
 768 int vmbus_open(struct vmbus_channel *newchannel,
 769                u32 send_ringbuffer_size, u32 recv_ringbuffer_size,
 770                void *userdata, u32 userdatalen,
 771                void (*onchannelcallback)(void *context), void *context)
 772 {
 773         int err;
 774
 775         err = vmbus_alloc_ring(newchannel, send_ringbuffer_size,
 776                                recv_ringbuffer_size);
 777         if (err)
 778                 return err;
 779
 780         err = __vmbus_open(newchannel, userdata, userdatalen,
 781                            onchannelcallback, context);
 782         if (err)
 783                 vmbus_free_ring(newchannel);
 784
 785         return err;
 786 }
 787 EXPORT_SYMBOL_GPL(vmbus_open);
 788
 789 /*
 790  * vmbus_teardown_gpadl -Teardown the specified GPADL handle
 791  */
 792 int vmbus_teardown_gpadl(struct vmbus_channel *channel, struct vmbus_gpadl *gpadl)
 793 {
 794         struct vmbus_channel_gpadl_teardown *msg;
 795         struct vmbus_channel_msginfo *info;
 796         unsigned long flags;
 797         int ret;
 798
 799         info = kzalloc(sizeof(*info) +
 800                        sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
 801         if (!info)
 802                 return -ENOMEM;
 803
 804         init_completion(&info->waitevent);
 805         info->waiting_channel = channel;
 806
 807         msg = (struct vmbus_channel_gpadl_teardown *)info->msg;
 808
 809         msg->header.msgtype = CHANNELMSG_GPADL_TEARDOWN;
 810         msg->child_relid = channel->offermsg.child_relid;
 811         msg->gpadl = gpadl->gpadl_handle;
 812
 813         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 814         list_add_tail(&info->msglistentry,
 815                       &vmbus_connection.chn_msg_list);
 816         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 817
 818         if (channel->rescind)
 819                 goto post_msg_err;
 820
 821         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_gpadl_teardown),
 822                              true);
 823
 824         trace_vmbus_teardown_gpadl(msg, ret);
 825
 826         if (ret)
 827                 goto post_msg_err;
 828
 829         wait_for_completion(&info->waitevent);
 830
 831         gpadl->gpadl_handle = 0;
 832
 833 post_msg_err:
 834         /*
 835          * If the channel has been rescinded;
 836          * we will be awakened by the rescind
 837          * handler; set the error code to zero so we don't leak memory.
 838          */
 839         if (channel->rescind)
 840                 ret = 0;
 841
 842         spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 843         list_del(&info->msglistentry);
 844         spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 845
 846         kfree(info);
 847
 848         ret = set_memory_encrypted((unsigned long)gpadl->buffer,
 849                                    PFN_UP(gpadl->size));
 850         if (ret)
 851                 pr_warn("Fail to set mem host visibility in GPADL teardown %d.\n", ret);
 852
 853         return ret;
 854 }
 855 EXPORT_SYMBOL_GPL(vmbus_teardown_gpadl);
 856
 857 void vmbus_reset_channel_cb(struct vmbus_channel *channel)
 858 {
 859         unsigned long flags;
 860
 861         /*
 862          * vmbus_on_event(), running in the per-channel tasklet, can race
 863          * with vmbus_close_internal() in the case of SMP guest, e.g., when
 864          * the former is accessing channel->inbound.ring_buffer, the latter
 865          * could be freeing the ring_buffer pages, so here we must stop it
 866          * first.
 867          *
 868          * vmbus_chan_sched() might call the netvsc driver callback function
 869          * that ends up scheduling NAPI work that accesses the ring buffer.
 870          * At this point, we have to ensure that any such work is completed
 871          * and that the channel ring buffer is no longer being accessed, cf.
 872          * the calls to napi_disable() in netvsc_device_remove().
 873          */
 874         tasklet_disable(&channel->callback_event);
 875
 876         /* See the inline comments in vmbus_chan_sched(). */
 877         spin_lock_irqsave(&channel->sched_lock, flags);
 878         channel->onchannel_callback = NULL;
 879         spin_unlock_irqrestore(&channel->sched_lock, flags);
 880
 881         channel->sc_creation_callback = NULL;
 882
 883         /* Re-enable tasklet for use on re-open */
 884         tasklet_enable(&channel->callback_event);
 885 }
 886
 887 static int vmbus_close_internal(struct vmbus_channel *channel)
 888 {
 889         struct vmbus_channel_close_channel *msg;
 890         int ret;
 891
 892         vmbus_reset_channel_cb(channel);
 893
 894         /*
 895          * In case a device driver's probe() fails (e.g.,
 896          * util_probe() -> vmbus_open() returns -ENOMEM) and the device is
 897          * rescinded later (e.g., we dynamically disable an Integrated Service
 898          * in Hyper-V Manager), the driver's remove() invokes vmbus_close():
 899          * here we should skip most of the below cleanup work.
 900          */
 901         if (channel->state != CHANNEL_OPENED_STATE)
 902                 return -EINVAL;
 903
 904         channel->state = CHANNEL_OPEN_STATE;
 905
 906         /* Send a closing message */
 907
 908         msg = &channel->close_msg.msg;
 909
 910         msg->header.msgtype = CHANNELMSG_CLOSECHANNEL;
 911         msg->child_relid = channel->offermsg.child_relid;
 912
 913         ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_close_channel),
 914                              true);
 915
 916         trace_vmbus_close_internal(msg, ret);
 917
 918         if (ret) {
 919                 pr_err("Close failed: close post msg return is %d\n", ret);
 920                 /*
 921                  * If we failed to post the close msg,
 922                  * it is perhaps better to leak memory.
 923                  */
 924         }
 925
 926         /* Tear down the gpadl for the channel's ring buffer */
 927         else if (channel->ringbuffer_gpadlhandle.gpadl_handle) {
 928                 ret = vmbus_teardown_gpadl(channel, &channel->ringbuffer_gpadlhandle);
 929                 if (ret) {
 930                         pr_err("Close failed: teardown gpadl return %d\n", ret);
 931                         /*
 932                          * If we failed to teardown gpadl,
 933                          * it is perhaps better to leak memory.
 934                          */
 935                 }
 936         }
 937
 938         if (!ret)
 939                 vmbus_free_requestor(&channel->requestor);
 940
 941         return ret;
 942 }
 943
 944 /* disconnect ring - close all channels */
 945 int vmbus_disconnect_ring(struct vmbus_channel *channel)
 946 {
 947         struct vmbus_channel *cur_channel, *tmp;
 948         int ret;
 949
 950         if (channel->primary_channel != NULL)
 951                 return -EINVAL;
 952
 953         list_for_each_entry_safe(cur_channel, tmp, &channel->sc_list, sc_list) {
 954                 if (cur_channel->rescind)
 955                         wait_for_completion(&cur_channel->rescind_event);
 956
 957                 mutex_lock(&vmbus_connection.channel_mutex);
 958                 if (vmbus_close_internal(cur_channel) == 0) {
 959                         vmbus_free_ring(cur_channel);
 960
 961                         if (cur_channel->rescind)
 962                                 hv_process_channel_removal(cur_channel);
 963                 }
 964                 mutex_unlock(&vmbus_connection.channel_mutex);
 965         }
 966
 967         /*
 968          * Now close the primary.
 969          */
 970         mutex_lock(&vmbus_connection.channel_mutex);
 971         ret = vmbus_close_internal(channel);
 972         mutex_unlock(&vmbus_connection.channel_mutex);
 973
 974         return ret;
 975 }
 976 EXPORT_SYMBOL_GPL(vmbus_disconnect_ring);
 977
 978 /*
 979  * vmbus_close - Close the specified channel
 980  */
 981 void vmbus_close(struct vmbus_channel *channel)
 982 {
 983         if (vmbus_disconnect_ring(channel) == 0)
 984                 vmbus_free_ring(channel);
 985 }
 986 EXPORT_SYMBOL_GPL(vmbus_close);
 987
 988 /**
 989  * vmbus_sendpacket_getid() - Send the specified buffer on the given channel
 990  * @channel: Pointer to vmbus_channel structure
 991  * @buffer: Pointer to the buffer you want to send the data from.
 992  * @bufferlen: Maximum size of what the buffer holds.
 993  * @requestid: Identifier of the request
 994  * @trans_id: Identifier of the transaction associated to this request, if
 995  *            the send is successful; undefined, otherwise.
 996  * @type: Type of packet that is being sent e.g. negotiate, time
 997  *        packet etc.
 998  * @flags: 0 or VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED
 999  *
1000  * Sends data in @buffer directly to Hyper-V via the vmbus.
1001  * This will send the data unparsed to Hyper-V.
1002  *
1003  * Mainly used by Hyper-V drivers.
1004  */
1005 int vmbus_sendpacket_getid(struct vmbus_channel *channel, void *buffer,
1006                            u32 bufferlen, u64 requestid, u64 *trans_id,
1007                            enum vmbus_packet_type type, u32 flags)
1008 {
1009         struct vmpacket_descriptor desc;
1010         u32 packetlen = sizeof(struct vmpacket_descriptor) + bufferlen;
1011         u32 packetlen_aligned = ALIGN(packetlen, sizeof(u64));
1012         struct kvec bufferlist[3];
1013         u64 aligned_data = 0;
1014         int num_vecs = ((bufferlen != 0) ? 3 : 1);
1015
1016
1017         /* Setup the descriptor */
1018         desc.type = type; /* VmbusPacketTypeDataInBand; */
1019         desc.flags = flags; /* VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED; */
1020         /* in 8-bytes granularity */
1021         desc.offset8 = sizeof(struct vmpacket_descriptor) >> 3;
1022         desc.len8 = (u16)(packetlen_aligned >> 3);
1023         desc.trans_id = VMBUS_RQST_ERROR; /* will be updated in hv_ringbuffer_write() */
1024
1025         bufferlist[0].iov_base = &desc;
1026         bufferlist[0].iov_len = sizeof(struct vmpacket_descriptor);
1027         bufferlist[1].iov_base = buffer;
1028         bufferlist[1].iov_len = bufferlen;
1029         bufferlist[2].iov_base = &aligned_data;
1030         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
1031
1032         return hv_ringbuffer_write(channel, bufferlist, num_vecs, requestid, trans_id);
1033 }
1034 EXPORT_SYMBOL(vmbus_sendpacket_getid);
1035
1036 /**
1037  * vmbus_sendpacket() - Send the specified buffer on the given channel
1038  * @channel: Pointer to vmbus_channel structure
1039  * @buffer: Pointer to the buffer you want to send the data from.
1040  * @bufferlen: Maximum size of what the buffer holds.
1041  * @requestid: Identifier of the request
1042  * @type: Type of packet that is being sent e.g. negotiate, time
1043  *        packet etc.
1044  * @flags: 0 or VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED
1045  *
1046  * Sends data in @buffer directly to Hyper-V via the vmbus.
1047  * This will send the data unparsed to Hyper-V.
1048  *
1049  * Mainly used by Hyper-V drivers.
1050  */
1051 int vmbus_sendpacket(struct vmbus_channel *channel, void *buffer,
1052                      u32 bufferlen, u64 requestid,
1053                      enum vmbus_packet_type type, u32 flags)
1054 {
1055         return vmbus_sendpacket_getid(channel, buffer, bufferlen,
1056                                       requestid, NULL, type, flags);
1057 }
1058 EXPORT_SYMBOL(vmbus_sendpacket);
1059
1060 /*
1061  * vmbus_sendpacket_pagebuffer - Send a range of single-page buffer
1062  * packets using a GPADL Direct packet type. This interface allows you
1063  * to control notifying the host. This will be useful for sending
1064  * batched data. Also the sender can control the send flags
1065  * explicitly.
1066  */
1067 int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
1068                                 struct hv_page_buffer pagebuffers[],
1069                                 u32 pagecount, void *buffer, u32 bufferlen,
1070                                 u64 requestid)
1071 {
1072         int i;
1073         struct vmbus_channel_packet_page_buffer desc;
1074         u32 descsize;
1075         u32 packetlen;
1076         u32 packetlen_aligned;
1077         struct kvec bufferlist[3];
1078         u64 aligned_data = 0;
1079
1080         if (pagecount > MAX_PAGE_BUFFER_COUNT)
1081                 return -EINVAL;
1082
1083         /*
1084          * Adjust the size down since vmbus_channel_packet_page_buffer is the
1085          * largest size we support
1086          */
1087         descsize = sizeof(struct vmbus_channel_packet_page_buffer) -
1088                           ((MAX_PAGE_BUFFER_COUNT - pagecount) *
1089                           sizeof(struct hv_page_buffer));
1090         packetlen = descsize + bufferlen;
1091         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
1092
1093         /* Setup the descriptor */
1094         desc.type = VM_PKT_DATA_USING_GPA_DIRECT;
1095         desc.flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
1096         desc.dataoffset8 = descsize >> 3; /* in 8-bytes granularity */
1097         desc.length8 = (u16)(packetlen_aligned >> 3);
1098         desc.transactionid = VMBUS_RQST_ERROR; /* will be updated in hv_ringbuffer_write() */
1099         desc.reserved = 0;
1100         desc.rangecount = pagecount;
1101
1102         for (i = 0; i < pagecount; i++) {
1103                 desc.range[i].len = pagebuffers[i].len;
1104                 desc.range[i].offset = pagebuffers[i].offset;
1105                 desc.range[i].pfn        = pagebuffers[i].pfn;
1106         }
1107
1108         bufferlist[0].iov_base = &desc;
1109         bufferlist[0].iov_len = descsize;
1110         bufferlist[1].iov_base = buffer;
1111         bufferlist[1].iov_len = bufferlen;
1112         bufferlist[2].iov_base = &aligned_data;
1113         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
1114
1115         return hv_ringbuffer_write(channel, bufferlist, 3, requestid, NULL);
1116 }
1117 EXPORT_SYMBOL_GPL(vmbus_sendpacket_pagebuffer);
1118
1119 /*
1120  * vmbus_sendpacket_multipagebuffer - Send a multi-page buffer packet
1121  * using a GPADL Direct packet type.
1122  * The buffer includes the vmbus descriptor.
1123  */
1124 int vmbus_sendpacket_mpb_desc(struct vmbus_channel *channel,
1125                               struct vmbus_packet_mpb_array *desc,
1126                               u32 desc_size,
1127                               void *buffer, u32 bufferlen, u64 requestid)
1128 {
1129         u32 packetlen;
1130         u32 packetlen_aligned;
1131         struct kvec bufferlist[3];
1132         u64 aligned_data = 0;
1133
1134         packetlen = desc_size + bufferlen;
1135         packetlen_aligned = ALIGN(packetlen, sizeof(u64));
1136
1137         /* Setup the descriptor */
1138         desc->type = VM_PKT_DATA_USING_GPA_DIRECT;
1139         desc->flags = VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED;
1140         desc->dataoffset8 = desc_size >> 3; /* in 8-bytes granularity */
1141         desc->length8 = (u16)(packetlen_aligned >> 3);
1142         desc->transactionid = VMBUS_RQST_ERROR; /* will be updated in hv_ringbuffer_write() */
1143         desc->reserved = 0;
1144         desc->rangecount = 1;
1145
1146         bufferlist[0].iov_base = desc;
1147         bufferlist[0].iov_len = desc_size;
1148         bufferlist[1].iov_base = buffer;
1149         bufferlist[1].iov_len = bufferlen;
1150         bufferlist[2].iov_base = &aligned_data;
1151         bufferlist[2].iov_len = (packetlen_aligned - packetlen);
1152
1153         return hv_ringbuffer_write(channel, bufferlist, 3, requestid, NULL);
1154 }
1155 EXPORT_SYMBOL_GPL(vmbus_sendpacket_mpb_desc);
1156
1157 /**
1158  * __vmbus_recvpacket() - Retrieve the user packet on the specified channel
1159  * @channel: Pointer to vmbus_channel structure
1160  * @buffer: Pointer to the buffer you want to receive the data into.
1161  * @bufferlen: Maximum size of what the buffer can hold.
1162  * @buffer_actual_len: The actual size of the data after it was received.
1163  * @requestid: Identifier of the request
1164  * @raw: true means keep the vmpacket_descriptor header in the received data.
1165  *
1166  * Receives directly from the hyper-v vmbus and puts the data it received
1167  * into Buffer. This will receive the data unparsed from hyper-v.
1168  *
1169  * Mainly used by Hyper-V drivers.
1170  */
1171 static inline int
1172 __vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
1173                    u32 bufferlen, u32 *buffer_actual_len, u64 *requestid,
1174                    bool raw)
1175 {
1176         return hv_ringbuffer_read(channel, buffer, bufferlen,
1177                                   buffer_actual_len, requestid, raw);
1178
1179 }
1180
1181 int vmbus_recvpacket(struct vmbus_channel *channel, void *buffer,
1182                      u32 bufferlen, u32 *buffer_actual_len,
1183                      u64 *requestid)
1184 {
1185         return __vmbus_recvpacket(channel, buffer, bufferlen,
1186                                   buffer_actual_len, requestid, false);
1187 }
1188 EXPORT_SYMBOL(vmbus_recvpacket);
1189
1190 /*
1191  * vmbus_recvpacket_raw - Retrieve the raw packet on the specified channel
1192  */
1193 int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
1194                               u32 bufferlen, u32 *buffer_actual_len,
1195                               u64 *requestid)
1196 {
1197         return __vmbus_recvpacket(channel, buffer, bufferlen,
1198                                   buffer_actual_len, requestid, true);
1199 }
1200 EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);
1201
1202 /*
1203  * vmbus_next_request_id - Returns a new request id. It is also
1204  * the index at which the guest memory address is stored.
1205  * Uses a spin lock to avoid race conditions.
1206  * @channel: Pointer to the VMbus channel struct
1207  * @rqst_add: Guest memory address to be stored in the array
1208  */
1209 u64 vmbus_next_request_id(struct vmbus_channel *channel, u64 rqst_addr)
1210 {
1211         struct vmbus_requestor *rqstor = &channel->requestor;
1212         unsigned long flags;
1213         u64 current_id;
1214
1215         /* Check rqstor has been initialized */
1216         if (!channel->rqstor_size)
1217                 return VMBUS_NO_RQSTOR;
1218
1219         lock_requestor(channel, flags);
1220         current_id = rqstor->next_request_id;
1221
1222         /* Requestor array is full */
1223         if (current_id >= rqstor->size) {
1224                 unlock_requestor(channel, flags);
1225                 return VMBUS_RQST_ERROR;
1226         }
1227
1228         rqstor->next_request_id = rqstor->req_arr[current_id];
1229         rqstor->req_arr[current_id] = rqst_addr;
1230
1231         /* The already held spin lock provides atomicity */
1232         bitmap_set(rqstor->req_bitmap, current_id, 1);
1233
1234         unlock_requestor(channel, flags);
1235
1236         /*
1237          * Cannot return an ID of 0, which is reserved for an unsolicited
1238          * message from Hyper-V; Hyper-V does not acknowledge (respond to)
1239          * VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED requests with ID of
1240          * 0 sent by the guest.
1241          */
1242         return current_id + 1;
1243 }
1244 EXPORT_SYMBOL_GPL(vmbus_next_request_id);
1245
1246 /* As in vmbus_request_addr_match() but without the requestor lock */
1247 u64 __vmbus_request_addr_match(struct vmbus_channel *channel, u64 trans_id,
1248                                u64 rqst_addr)
1249 {
1250         struct vmbus_requestor *rqstor = &channel->requestor;
1251         u64 req_addr;
1252
1253         /* Check rqstor has been initialized */
1254         if (!channel->rqstor_size)
1255                 return VMBUS_NO_RQSTOR;
1256
1257         /* Hyper-V can send an unsolicited message with ID of 0 */
1258         if (!trans_id)
1259                 return VMBUS_RQST_ERROR;
1260
1261         /* Data corresponding to trans_id is stored at trans_id - 1 */
1262         trans_id--;
1263
1264         /* Invalid trans_id */
1265         if (trans_id >= rqstor->size || !test_bit(trans_id, rqstor->req_bitmap))
1266                 return VMBUS_RQST_ERROR;
1267
1268         req_addr = rqstor->req_arr[trans_id];
1269         if (rqst_addr == VMBUS_RQST_ADDR_ANY || req_addr == rqst_addr) {
1270                 rqstor->req_arr[trans_id] = rqstor->next_request_id;
1271                 rqstor->next_request_id = trans_id;
1272
1273                 /* The already held spin lock provides atomicity */
1274                 bitmap_clear(rqstor->req_bitmap, trans_id, 1);
1275         }
1276
1277         return req_addr;
1278 }
1279 EXPORT_SYMBOL_GPL(__vmbus_request_addr_match);
1280
1281 /*
1282  * vmbus_request_addr_match - Clears/removes @trans_id from the @channel's
1283  * requestor, provided the memory address stored at @trans_id equals @rqst_addr
1284  * (or provided @rqst_addr matches the sentinel value VMBUS_RQST_ADDR_ANY).
1285  *
1286  * Returns the memory address stored at @trans_id, or VMBUS_RQST_ERROR if
1287  * @trans_id is not contained in the requestor.
1288  *
1289  * Acquires and releases the requestor spin lock.
1290  */
1291 u64 vmbus_request_addr_match(struct vmbus_channel *channel, u64 trans_id,
1292                              u64 rqst_addr)
1293 {
1294         unsigned long flags;
1295         u64 req_addr;
1296
1297         lock_requestor(channel, flags);
1298         req_addr = __vmbus_request_addr_match(channel, trans_id, rqst_addr);
1299         unlock_requestor(channel, flags);
1300
1301         return req_addr;
1302 }
1303 EXPORT_SYMBOL_GPL(vmbus_request_addr_match);
1304
1305 /*
1306  * vmbus_request_addr - Returns the memory address stored at @trans_id
1307  * in @rqstor. Uses a spin lock to avoid race conditions.
1308  * @channel: Pointer to the VMbus channel struct
1309  * @trans_id: Request id sent back from Hyper-V. Becomes the requestor's
1310  * next request id.
1311  */
1312 u64 vmbus_request_addr(struct vmbus_channel *channel, u64 trans_id)
1313 {
1314         return vmbus_request_addr_match(channel, trans_id, VMBUS_RQST_ADDR_ANY);
1315 }
1316 EXPORT_SYMBOL_GPL(vmbus_request_addr);