drivers/hv/hv_kvp.c

   1 /*
   2  * An implementation of key value pair (KVP) functionality for Linux.
   3  *
   4  *
   5  * Copyright (C) 2010, Novell, Inc.
   6  * Author : K. Y. Srinivasan <[email protected]>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License version 2 as published
  10  * by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  15  * NON INFRINGEMENT.  See the GNU General Public License for more
  16  * details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  21  *
  22  */
  23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  24
  25 #include <linux/net.h>
  26 #include <linux/nls.h>
  27 #include <linux/connector.h>
  28 #include <linux/workqueue.h>
  29 #include <linux/hyperv.h>
  30
  31
  32 /*
  33  * Pre win8 version numbers used in ws2008 and ws 2008 r2 (win7)
  34  */
  35 #define WIN7_SRV_MAJOR   3
  36 #define WIN7_SRV_MINOR   0
  37 #define WIN7_SRV_MAJOR_MINOR     (WIN7_SRV_MAJOR << 16 | WIN7_SRV_MINOR)
  38
  39 #define WIN8_SRV_MAJOR   4
  40 #define WIN8_SRV_MINOR   0
  41 #define WIN8_SRV_MAJOR_MINOR     (WIN8_SRV_MAJOR << 16 | WIN8_SRV_MINOR)
  42
  43 /*
  44  * Global state maintained for transaction that is being processed.
  45  * Note that only one transaction can be active at any point in time.
  46  *
  47  * This state is set when we receive a request from the host; we
  48  * cleanup this state when the transaction is completed - when we respond
  49  * to the host with the key value.
  50  */
  51
  52 static struct {
  53         bool active; /* transaction status - active or not */
  54         int recv_len; /* number of bytes received. */
  55         struct hv_kvp_msg  *kvp_msg; /* current message */
  56         struct vmbus_channel *recv_channel; /* chn we got the request */
  57         u64 recv_req_id; /* request ID. */
  58         void *kvp_context; /* for the channel callback */
  59 } kvp_transaction;
  60
  61 /*
  62  * Before we can accept KVP messages from the host, we need
  63  * to handshake with the user level daemon. This state tracks
  64  * if we are in the handshake phase.
  65  */
  66 static bool in_hand_shake = true;
  67
  68 /*
  69  * This state maintains the version number registered by the daemon.
  70  */
  71 static int dm_reg_value;
  72
  73 static void kvp_send_key(struct work_struct *dummy);
  74
  75
  76 static void kvp_respond_to_host(struct hv_kvp_msg *msg, int error);
  77 static void kvp_work_func(struct work_struct *dummy);
  78 static void kvp_register(int);
  79
  80 static DECLARE_DELAYED_WORK(kvp_work, kvp_work_func);
  81 static DECLARE_WORK(kvp_sendkey_work, kvp_send_key);
  82
  83 static struct cb_id kvp_id = { CN_KVP_IDX, CN_KVP_VAL };
  84 static const char kvp_name[] = "kvp_kernel_module";
  85 static u8 *recv_buffer;
  86 /*
  87  * Register the kernel component with the user-level daemon.
  88  * As part of this registration, pass the LIC version number.
  89  * This number has no meaning, it satisfies the registration protocol.
  90  */
  91 #define HV_DRV_VERSION           "3.1"
  92
  93 static void
  94 kvp_register(int reg_value)
  95 {
  96
  97         struct cn_msg *msg;
  98         struct hv_kvp_msg *kvp_msg;
  99         char *version;
 100
 101         msg = kzalloc(sizeof(*msg) + sizeof(struct hv_kvp_msg), GFP_ATOMIC);
 102
 103         if (msg) {
 104                 kvp_msg = (struct hv_kvp_msg *)msg->data;
 105                 version = kvp_msg->body.kvp_register.version;
 106                 msg->id.idx =  CN_KVP_IDX;
 107                 msg->id.val = CN_KVP_VAL;
 108
 109                 kvp_msg->kvp_hdr.operation = reg_value;
 110                 strcpy(version, HV_DRV_VERSION);
 111                 msg->len = sizeof(struct hv_kvp_msg);
 112                 cn_netlink_send(msg, 0, GFP_ATOMIC);
 113                 kfree(msg);
 114         }
 115 }
 116 static void
 117 kvp_work_func(struct work_struct *dummy)
 118 {
 119         /*
 120          * If the timer fires, the user-mode component has not responded;
 121          * process the pending transaction.
 122          */
 123         kvp_respond_to_host(NULL, HV_E_FAIL);
 124 }
 125
 126 static int kvp_handle_handshake(struct hv_kvp_msg *msg)
 127 {
 128         int ret = 1;
 129
 130         switch (msg->kvp_hdr.operation) {
 131         case KVP_OP_REGISTER:
 132                 dm_reg_value = KVP_OP_REGISTER;
 133                 pr_info("KVP: IP injection functionality not available\n");
 134                 pr_info("KVP: Upgrade the KVP daemon\n");
 135                 break;
 136         case KVP_OP_REGISTER1:
 137                 dm_reg_value = KVP_OP_REGISTER1;
 138                 break;
 139         default:
 140                 pr_info("KVP: incompatible daemon\n");
 141                 pr_info("KVP: KVP version: %d, Daemon version: %d\n",
 142                         KVP_OP_REGISTER1, msg->kvp_hdr.operation);
 143                 ret = 0;
 144         }
 145
 146         if (ret) {
 147                 /*
 148                  * We have a compatible daemon; complete the handshake.
 149                  */
 150                 pr_info("KVP: user-mode registering done.\n");
 151                 kvp_register(dm_reg_value);
 152                 kvp_transaction.active = false;
 153                 if (kvp_transaction.kvp_context)
 154                         hv_kvp_onchannelcallback(kvp_transaction.kvp_context);
 155         }
 156         return ret;
 157 }
 158
 159
 160 /*
 161  * Callback when data is received from user mode.
 162  */
 163
 164 static void
 165 kvp_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
 166 {
 167         struct hv_kvp_msg *message;
 168         struct hv_kvp_msg_enumerate *data;
 169         int     error = 0;
 170
 171         message = (struct hv_kvp_msg *)msg->data;
 172
 173         /*
 174          * If we are negotiating the version information
 175          * with the daemon; handle that first.
 176          */
 177
 178         if (in_hand_shake) {
 179                 if (kvp_handle_handshake(message))
 180                         in_hand_shake = false;
 181                 return;
 182         }
 183
 184         /*
 185          * Based on the version of the daemon, we propagate errors from the
 186          * daemon differently.
 187          */
 188
 189         data = &message->body.kvp_enum_data;
 190
 191         switch (dm_reg_value) {
 192         case KVP_OP_REGISTER:
 193                 /*
 194                  * Null string is used to pass back error condition.
 195                  */
 196                 if (data->data.key[0] == 0)
 197                         error = HV_S_CONT;
 198                 break;
 199
 200         case KVP_OP_REGISTER1:
 201                 /*
 202                  * We use the message header information from
 203                  * the user level daemon to transmit errors.
 204                  */
 205                 error = message->error;
 206                 break;
 207         }
 208
 209         /*
 210          * Complete the transaction by forwarding the key value
 211          * to the host. But first, cancel the timeout.
 212          */
 213         if (cancel_delayed_work_sync(&kvp_work))
 214                 kvp_respond_to_host(message, error);
 215 }
 216
 217
 218 static int process_ob_ipinfo(void *in_msg, void *out_msg, int op)
 219 {
 220         struct hv_kvp_msg *in = in_msg;
 221         struct hv_kvp_ip_msg *out = out_msg;
 222         int len;
 223
 224         switch (op) {
 225         case KVP_OP_GET_IP_INFO:
 226                 /*
 227                  * Transform all parameters into utf16 encoding.
 228                  */
 229                 len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.ip_addr,
 230                                 strlen((char *)in->body.kvp_ip_val.ip_addr),
 231                                 UTF16_HOST_ENDIAN,
 232                                 (wchar_t *)out->kvp_ip_val.ip_addr,
 233                                 MAX_IP_ADDR_SIZE);
 234                 if (len < 0)
 235                         return len;
 236
 237                 len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.sub_net,
 238                                 strlen((char *)in->body.kvp_ip_val.sub_net),
 239                                 UTF16_HOST_ENDIAN,
 240                                 (wchar_t *)out->kvp_ip_val.sub_net,
 241                                 MAX_IP_ADDR_SIZE);
 242                 if (len < 0)
 243                         return len;
 244
 245                 len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.gate_way,
 246                                 strlen((char *)in->body.kvp_ip_val.gate_way),
 247                                 UTF16_HOST_ENDIAN,
 248                                 (wchar_t *)out->kvp_ip_val.gate_way,
 249                                 MAX_GATEWAY_SIZE);
 250                 if (len < 0)
 251                         return len;
 252
 253                 len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.dns_addr,
 254                                 strlen((char *)in->body.kvp_ip_val.dns_addr),
 255                                 UTF16_HOST_ENDIAN,
 256                                 (wchar_t *)out->kvp_ip_val.dns_addr,
 257                                 MAX_IP_ADDR_SIZE);
 258                 if (len < 0)
 259                         return len;
 260
 261                 len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.adapter_id,
 262                                 strlen((char *)in->body.kvp_ip_val.adapter_id),
 263                                 UTF16_HOST_ENDIAN,
 264                                 (wchar_t *)out->kvp_ip_val.adapter_id,
 265                                 MAX_IP_ADDR_SIZE);
 266                 if (len < 0)
 267                         return len;
 268
 269                 out->kvp_ip_val.dhcp_enabled =
 270                         in->body.kvp_ip_val.dhcp_enabled;
 271                 out->kvp_ip_val.addr_family =
 272                         in->body.kvp_ip_val.addr_family;
 273         }
 274
 275         return 0;
 276 }
 277
 278 static void process_ib_ipinfo(void *in_msg, void *out_msg, int op)
 279 {
 280         struct hv_kvp_ip_msg *in = in_msg;
 281         struct hv_kvp_msg *out = out_msg;
 282
 283         switch (op) {
 284         case KVP_OP_SET_IP_INFO:
 285                 /*
 286                  * Transform all parameters into utf8 encoding.
 287                  */
 288                 utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.ip_addr,
 289                                 MAX_IP_ADDR_SIZE,
 290                                 UTF16_LITTLE_ENDIAN,
 291                                 (__u8 *)out->body.kvp_ip_val.ip_addr,
 292                                 MAX_IP_ADDR_SIZE);
 293
 294                 utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.sub_net,
 295                                 MAX_IP_ADDR_SIZE,
 296                                 UTF16_LITTLE_ENDIAN,
 297                                 (__u8 *)out->body.kvp_ip_val.sub_net,
 298                                 MAX_IP_ADDR_SIZE);
 299
 300                 utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.gate_way,
 301                                 MAX_GATEWAY_SIZE,
 302                                 UTF16_LITTLE_ENDIAN,
 303                                 (__u8 *)out->body.kvp_ip_val.gate_way,
 304                                 MAX_GATEWAY_SIZE);
 305
 306                 utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.dns_addr,
 307                                 MAX_IP_ADDR_SIZE,
 308                                 UTF16_LITTLE_ENDIAN,
 309                                 (__u8 *)out->body.kvp_ip_val.dns_addr,
 310                                 MAX_IP_ADDR_SIZE);
 311
 312                 out->body.kvp_ip_val.dhcp_enabled = in->kvp_ip_val.dhcp_enabled;
 313
 314         default:
 315                 utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.adapter_id,
 316                                 MAX_ADAPTER_ID_SIZE,
 317                                 UTF16_LITTLE_ENDIAN,
 318                                 (__u8 *)out->body.kvp_ip_val.adapter_id,
 319                                 MAX_ADAPTER_ID_SIZE);
 320
 321                 out->body.kvp_ip_val.addr_family = in->kvp_ip_val.addr_family;
 322         }
 323 }
 324
 325
 326
 327
 328 static void
 329 kvp_send_key(struct work_struct *dummy)
 330 {
 331         struct cn_msg *msg;
 332         struct hv_kvp_msg *message;
 333         struct hv_kvp_msg *in_msg;
 334         __u8 operation = kvp_transaction.kvp_msg->kvp_hdr.operation;
 335         __u8 pool = kvp_transaction.kvp_msg->kvp_hdr.pool;
 336         __u32 val32;
 337         __u64 val64;
 338
 339         msg = kzalloc(sizeof(*msg) + sizeof(struct hv_kvp_msg) , GFP_ATOMIC);
 340         if (!msg)
 341                 return;
 342
 343         msg->id.idx =  CN_KVP_IDX;
 344         msg->id.val = CN_KVP_VAL;
 345
 346         message = (struct hv_kvp_msg *)msg->data;
 347         message->kvp_hdr.operation = operation;
 348         message->kvp_hdr.pool = pool;
 349         in_msg = kvp_transaction.kvp_msg;
 350
 351         /*
 352          * The key/value strings sent from the host are encoded in
 353          * in utf16; convert it to utf8 strings.
 354          * The host assures us that the utf16 strings will not exceed
 355          * the max lengths specified. We will however, reserve room
 356          * for the string terminating character - in the utf16s_utf8s()
 357          * function we limit the size of the buffer where the converted
 358          * string is placed to HV_KVP_EXCHANGE_MAX_*_SIZE -1 to gaurantee
 359          * that the strings can be properly terminated!
 360          */
 361
 362         switch (message->kvp_hdr.operation) {
 363         case KVP_OP_SET_IP_INFO:
 364                 process_ib_ipinfo(in_msg, message, KVP_OP_SET_IP_INFO);
 365                 break;
 366         case KVP_OP_GET_IP_INFO:
 367                 process_ib_ipinfo(in_msg, message, KVP_OP_GET_IP_INFO);
 368                 break;
 369         case KVP_OP_SET:
 370                 switch (in_msg->body.kvp_set.data.value_type) {
 371                 case REG_SZ:
 372                         /*
 373                          * The value is a string - utf16 encoding.
 374                          */
 375                         message->body.kvp_set.data.value_size =
 376                                 utf16s_to_utf8s(
 377                                 (wchar_t *)in_msg->body.kvp_set.data.value,
 378                                 in_msg->body.kvp_set.data.value_size,
 379                                 UTF16_LITTLE_ENDIAN,
 380                                 message->body.kvp_set.data.value,
 381                                 HV_KVP_EXCHANGE_MAX_VALUE_SIZE - 1) + 1;
 382                                 break;
 383
 384                 case REG_U32:
 385                         /*
 386                          * The value is a 32 bit scalar.
 387                          * We save this as a utf8 string.
 388                          */
 389                         val32 = in_msg->body.kvp_set.data.value_u32;
 390                         message->body.kvp_set.data.value_size =
 391                                 sprintf(message->body.kvp_set.data.value,
 392                                         "%d", val32) + 1;
 393                         break;
 394
 395                 case REG_U64:
 396                         /*
 397                          * The value is a 64 bit scalar.
 398                          * We save this as a utf8 string.
 399                          */
 400                         val64 = in_msg->body.kvp_set.data.value_u64;
 401                         message->body.kvp_set.data.value_size =
 402                                 sprintf(message->body.kvp_set.data.value,
 403                                         "%llu", val64) + 1;
 404                         break;
 405
 406                 }
 407         case KVP_OP_GET:
 408                 message->body.kvp_set.data.key_size =
 409                         utf16s_to_utf8s(
 410                         (wchar_t *)in_msg->body.kvp_set.data.key,
 411                         in_msg->body.kvp_set.data.key_size,
 412                         UTF16_LITTLE_ENDIAN,
 413                         message->body.kvp_set.data.key,
 414                         HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
 415                         break;
 416
 417         case KVP_OP_DELETE:
 418                 message->body.kvp_delete.key_size =
 419                         utf16s_to_utf8s(
 420                         (wchar_t *)in_msg->body.kvp_delete.key,
 421                         in_msg->body.kvp_delete.key_size,
 422                         UTF16_LITTLE_ENDIAN,
 423                         message->body.kvp_delete.key,
 424                         HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
 425                         break;
 426
 427         case KVP_OP_ENUMERATE:
 428                 message->body.kvp_enum_data.index =
 429                         in_msg->body.kvp_enum_data.index;
 430                         break;
 431         }
 432
 433         msg->len = sizeof(struct hv_kvp_msg);
 434         cn_netlink_send(msg, 0, GFP_ATOMIC);
 435         kfree(msg);
 436
 437         return;
 438 }
 439
 440 /*
 441  * Send a response back to the host.
 442  */
 443
 444 static void
 445 kvp_respond_to_host(struct hv_kvp_msg *msg_to_host, int error)
 446 {
 447         struct hv_kvp_msg  *kvp_msg;
 448         struct hv_kvp_exchg_msg_value  *kvp_data;
 449         char    *key_name;
 450         char    *value;
 451         struct icmsg_hdr *icmsghdrp;
 452         int     keylen = 0;
 453         int     valuelen = 0;
 454         u32     buf_len;
 455         struct vmbus_channel *channel;
 456         u64     req_id;
 457         int ret;
 458
 459         /*
 460          * If a transaction is not active; log and return.
 461          */
 462
 463         if (!kvp_transaction.active) {
 464                 /*
 465                  * This is a spurious call!
 466                  */
 467                 pr_warn("KVP: Transaction not active\n");
 468                 return;
 469         }
 470         /*
 471          * Copy the global state for completing the transaction. Note that
 472          * only one transaction can be active at a time.
 473          */
 474
 475         buf_len = kvp_transaction.recv_len;
 476         channel = kvp_transaction.recv_channel;
 477         req_id = kvp_transaction.recv_req_id;
 478
 479         kvp_transaction.active = false;
 480
 481         icmsghdrp = (struct icmsg_hdr *)
 482                         &recv_buffer[sizeof(struct vmbuspipe_hdr)];
 483
 484         if (channel->onchannel_callback == NULL)
 485                 /*
 486                  * We have raced with util driver being unloaded;
 487                  * silently return.
 488                  */
 489                 return;
 490
 491         icmsghdrp->status = error;
 492
 493         /*
 494          * If the error parameter is set, terminate the host's enumeration
 495          * on this pool.
 496          */
 497         if (error) {
 498                 /*
 499                  * Something failed or we have timedout;
 500                  * terminate the current host-side iteration.
 501                  */
 502                 goto response_done;
 503         }
 504
 505         kvp_msg = (struct hv_kvp_msg *)
 506                         &recv_buffer[sizeof(struct vmbuspipe_hdr) +
 507                         sizeof(struct icmsg_hdr)];
 508
 509         switch (kvp_transaction.kvp_msg->kvp_hdr.operation) {
 510         case KVP_OP_GET_IP_INFO:
 511                 ret = process_ob_ipinfo(msg_to_host,
 512                                  (struct hv_kvp_ip_msg *)kvp_msg,
 513                                  KVP_OP_GET_IP_INFO);
 514                 if (ret < 0)
 515                         icmsghdrp->status = HV_E_FAIL;
 516
 517                 goto response_done;
 518         case KVP_OP_SET_IP_INFO:
 519                 goto response_done;
 520         case KVP_OP_GET:
 521                 kvp_data = &kvp_msg->body.kvp_get.data;
 522                 goto copy_value;
 523
 524         case KVP_OP_SET:
 525         case KVP_OP_DELETE:
 526                 goto response_done;
 527
 528         default:
 529                 break;
 530         }
 531
 532         kvp_data = &kvp_msg->body.kvp_enum_data.data;
 533         key_name = msg_to_host->body.kvp_enum_data.data.key;
 534
 535         /*
 536          * The windows host expects the key/value pair to be encoded
 537          * in utf16. Ensure that the key/value size reported to the host
 538          * will be less than or equal to the MAX size (including the
 539          * terminating character).
 540          */
 541         keylen = utf8s_to_utf16s(key_name, strlen(key_name), UTF16_HOST_ENDIAN,
 542                                 (wchar_t *) kvp_data->key,
 543                                 (HV_KVP_EXCHANGE_MAX_KEY_SIZE / 2) - 2);
 544         kvp_data->key_size = 2*(keylen + 1); /* utf16 encoding */
 545
 546 copy_value:
 547         value = msg_to_host->body.kvp_enum_data.data.value;
 548         valuelen = utf8s_to_utf16s(value, strlen(value), UTF16_HOST_ENDIAN,
 549                                 (wchar_t *) kvp_data->value,
 550                                 (HV_KVP_EXCHANGE_MAX_VALUE_SIZE / 2) - 2);
 551         kvp_data->value_size = 2*(valuelen + 1); /* utf16 encoding */
 552
 553         /*
 554          * If the utf8s to utf16s conversion failed; notify host
 555          * of the error.
 556          */
 557         if ((keylen < 0) || (valuelen < 0))
 558                 icmsghdrp->status = HV_E_FAIL;
 559
 560         kvp_data->value_type = REG_SZ; /* all our values are strings */
 561
 562 response_done:
 563         icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
 564
 565         vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
 566                                 VM_PKT_DATA_INBAND, 0);
 567
 568 }
 569
 570 /*
 571  * This callback is invoked when we get a KVP message from the host.
 572  * The host ensures that only one KVP transaction can be active at a time.
 573  * KVP implementation in Linux needs to forward the key to a user-mde
 574  * component to retrive the corresponding value. Consequently, we cannot
 575  * respond to the host in the conext of this callback. Since the host
 576  * guarantees that at most only one transaction can be active at a time,
 577  * we stash away the transaction state in a set of global variables.
 578  */
 579
 580 void hv_kvp_onchannelcallback(void *context)
 581 {
 582         struct vmbus_channel *channel = context;
 583         u32 recvlen;
 584         u64 requestid;
 585
 586         struct hv_kvp_msg *kvp_msg;
 587
 588         struct icmsg_hdr *icmsghdrp;
 589         struct icmsg_negotiate *negop = NULL;
 590
 591         if (kvp_transaction.active) {
 592                 /*
 593                  * We will defer processing this callback once
 594                  * the current transaction is complete.
 595                  */
 596                 kvp_transaction.kvp_context = context;
 597                 return;
 598         }
 599
 600         vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
 601                          &requestid);
 602
 603         if (recvlen > 0) {
 604                 icmsghdrp = (struct icmsg_hdr *)&recv_buffer[
 605                         sizeof(struct vmbuspipe_hdr)];
 606
 607                 if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
 608                         /*
 609                          * We start with win8 version and if the host cannot
 610                          * support that we use the previous version.
 611                          */
 612                         if (vmbus_prep_negotiate_resp(icmsghdrp, negop,
 613                                  recv_buffer, UTIL_FW_MAJOR_MINOR,
 614                                  WIN8_SRV_MAJOR_MINOR))
 615                                 goto done;
 616
 617                         vmbus_prep_negotiate_resp(icmsghdrp, negop,
 618                                  recv_buffer, UTIL_FW_MAJOR_MINOR,
 619                                  WIN7_SRV_MAJOR_MINOR);
 620
 621                 } else {
 622                         kvp_msg = (struct hv_kvp_msg *)&recv_buffer[
 623                                 sizeof(struct vmbuspipe_hdr) +
 624                                 sizeof(struct icmsg_hdr)];
 625
 626                         /*
 627                          * Stash away this global state for completing the
 628                          * transaction; note transactions are serialized.
 629                          */
 630
 631                         kvp_transaction.recv_len = recvlen;
 632                         kvp_transaction.recv_channel = channel;
 633                         kvp_transaction.recv_req_id = requestid;
 634                         kvp_transaction.active = true;
 635                         kvp_transaction.kvp_msg = kvp_msg;
 636
 637                         /*
 638                          * Get the information from the
 639                          * user-mode component.
 640                          * component. This transaction will be
 641                          * completed when we get the value from
 642                          * the user-mode component.
 643                          * Set a timeout to deal with
 644                          * user-mode not responding.
 645                          */
 646                         schedule_work(&kvp_sendkey_work);
 647                         schedule_delayed_work(&kvp_work, 5*HZ);
 648
 649                         return;
 650
 651                 }
 652 done:
 653
 654                 icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
 655                         | ICMSGHDRFLAG_RESPONSE;
 656
 657                 vmbus_sendpacket(channel, recv_buffer,
 658                                        recvlen, requestid,
 659                                        VM_PKT_DATA_INBAND, 0);
 660         }
 661
 662 }
 663
 664 int
 665 hv_kvp_init(struct hv_util_service *srv)
 666 {
 667         int err;
 668
 669         err = cn_add_callback(&kvp_id, kvp_name, kvp_cn_callback);
 670         if (err)
 671                 return err;
 672         recv_buffer = srv->recv_buffer;
 673
 674         /*
 675          * When this driver loads, the user level daemon that
 676          * processes the host requests may not yet be running.
 677          * Defer processing channel callbacks until the daemon
 678          * has registered.
 679          */
 680         kvp_transaction.active = true;
 681
 682         return 0;
 683 }
 684
 685 void hv_kvp_deinit(void)
 686 {
 687         cn_del_callback(&kvp_id);
 688         cancel_delayed_work_sync(&kvp_work);
 689         cancel_work_sync(&kvp_sendkey_work);
 690 }