linux/drivers/hv/hv_kvp.c
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   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 <ksrinivasan@novell.com>
   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 WS2008_SRV_MAJOR        1
  36#define WS2008_SRV_MINOR        0
  37#define WS2008_SRV_VERSION     (WS2008_SRV_MAJOR << 16 | WS2008_SRV_MINOR)
  38
  39#define WIN7_SRV_MAJOR   3
  40#define WIN7_SRV_MINOR   0
  41#define WIN7_SRV_VERSION     (WIN7_SRV_MAJOR << 16 | WIN7_SRV_MINOR)
  42
  43#define WIN8_SRV_MAJOR   4
  44#define WIN8_SRV_MINOR   0
  45#define WIN8_SRV_VERSION     (WIN8_SRV_MAJOR << 16 | WIN8_SRV_MINOR)
  46
  47/*
  48 * Global state maintained for transaction that is being processed.
  49 * Note that only one transaction can be active at any point in time.
  50 *
  51 * This state is set when we receive a request from the host; we
  52 * cleanup this state when the transaction is completed - when we respond
  53 * to the host with the key value.
  54 */
  55
  56static struct {
  57        bool active; /* transaction status - active or not */
  58        int recv_len; /* number of bytes received. */
  59        struct hv_kvp_msg  *kvp_msg; /* current message */
  60        struct vmbus_channel *recv_channel; /* chn we got the request */
  61        u64 recv_req_id; /* request ID. */
  62        void *kvp_context; /* for the channel callback */
  63} kvp_transaction;
  64
  65/*
  66 * Before we can accept KVP messages from the host, we need
  67 * to handshake with the user level daemon. This state tracks
  68 * if we are in the handshake phase.
  69 */
  70static bool in_hand_shake = true;
  71
  72/*
  73 * This state maintains the version number registered by the daemon.
  74 */
  75static int dm_reg_value;
  76
  77static void kvp_send_key(struct work_struct *dummy);
  78
  79
  80static void kvp_respond_to_host(struct hv_kvp_msg *msg, int error);
  81static void kvp_work_func(struct work_struct *dummy);
  82static void kvp_register(int);
  83
  84static DECLARE_DELAYED_WORK(kvp_work, kvp_work_func);
  85static DECLARE_WORK(kvp_sendkey_work, kvp_send_key);
  86
  87static struct cb_id kvp_id = { CN_KVP_IDX, CN_KVP_VAL };
  88static const char kvp_name[] = "kvp_kernel_module";
  89static u8 *recv_buffer;
  90/*
  91 * Register the kernel component with the user-level daemon.
  92 * As part of this registration, pass the LIC version number.
  93 * This number has no meaning, it satisfies the registration protocol.
  94 */
  95#define HV_DRV_VERSION           "3.1"
  96
  97static void
  98kvp_register(int reg_value)
  99{
 100
 101        struct cn_msg *msg;
 102        struct hv_kvp_msg *kvp_msg;
 103        char *version;
 104
 105        msg = kzalloc(sizeof(*msg) + sizeof(struct hv_kvp_msg), GFP_ATOMIC);
 106
 107        if (msg) {
 108                kvp_msg = (struct hv_kvp_msg *)msg->data;
 109                version = kvp_msg->body.kvp_register.version;
 110                msg->id.idx =  CN_KVP_IDX;
 111                msg->id.val = CN_KVP_VAL;
 112
 113                kvp_msg->kvp_hdr.operation = reg_value;
 114                strcpy(version, HV_DRV_VERSION);
 115                msg->len = sizeof(struct hv_kvp_msg);
 116                cn_netlink_send(msg, 0, GFP_ATOMIC);
 117                kfree(msg);
 118        }
 119}
 120static void
 121kvp_work_func(struct work_struct *dummy)
 122{
 123        /*
 124         * If the timer fires, the user-mode component has not responded;
 125         * process the pending transaction.
 126         */
 127        kvp_respond_to_host(NULL, HV_E_FAIL);
 128}
 129
 130static int kvp_handle_handshake(struct hv_kvp_msg *msg)
 131{
 132        int ret = 1;
 133
 134        switch (msg->kvp_hdr.operation) {
 135        case KVP_OP_REGISTER:
 136                dm_reg_value = KVP_OP_REGISTER;
 137                pr_info("KVP: IP injection functionality not available\n");
 138                pr_info("KVP: Upgrade the KVP daemon\n");
 139                break;
 140        case KVP_OP_REGISTER1:
 141                dm_reg_value = KVP_OP_REGISTER1;
 142                break;
 143        default:
 144                pr_info("KVP: incompatible daemon\n");
 145                pr_info("KVP: KVP version: %d, Daemon version: %d\n",
 146                        KVP_OP_REGISTER1, msg->kvp_hdr.operation);
 147                ret = 0;
 148        }
 149
 150        if (ret) {
 151                /*
 152                 * We have a compatible daemon; complete the handshake.
 153                 */
 154                pr_info("KVP: user-mode registering done.\n");
 155                kvp_register(dm_reg_value);
 156                kvp_transaction.active = false;
 157                if (kvp_transaction.kvp_context)
 158                        hv_kvp_onchannelcallback(kvp_transaction.kvp_context);
 159        }
 160        return ret;
 161}
 162
 163
 164/*
 165 * Callback when data is received from user mode.
 166 */
 167
 168static void
 169kvp_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
 170{
 171        struct hv_kvp_msg *message;
 172        struct hv_kvp_msg_enumerate *data;
 173        int     error = 0;
 174
 175        message = (struct hv_kvp_msg *)msg->data;
 176
 177        /*
 178         * If we are negotiating the version information
 179         * with the daemon; handle that first.
 180         */
 181
 182        if (in_hand_shake) {
 183                if (kvp_handle_handshake(message))
 184                        in_hand_shake = false;
 185                return;
 186        }
 187
 188        /*
 189         * Based on the version of the daemon, we propagate errors from the
 190         * daemon differently.
 191         */
 192
 193        data = &message->body.kvp_enum_data;
 194
 195        switch (dm_reg_value) {
 196        case KVP_OP_REGISTER:
 197                /*
 198                 * Null string is used to pass back error condition.
 199                 */
 200                if (data->data.key[0] == 0)
 201                        error = HV_S_CONT;
 202                break;
 203
 204        case KVP_OP_REGISTER1:
 205                /*
 206                 * We use the message header information from
 207                 * the user level daemon to transmit errors.
 208                 */
 209                error = message->error;
 210                break;
 211        }
 212
 213        /*
 214         * Complete the transaction by forwarding the key value
 215         * to the host. But first, cancel the timeout.
 216         */
 217        if (cancel_delayed_work_sync(&kvp_work))
 218                kvp_respond_to_host(message, error);
 219}
 220
 221
 222static int process_ob_ipinfo(void *in_msg, void *out_msg, int op)
 223{
 224        struct hv_kvp_msg *in = in_msg;
 225        struct hv_kvp_ip_msg *out = out_msg;
 226        int len;
 227
 228        switch (op) {
 229        case KVP_OP_GET_IP_INFO:
 230                /*
 231                 * Transform all parameters into utf16 encoding.
 232                 */
 233                len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.ip_addr,
 234                                strlen((char *)in->body.kvp_ip_val.ip_addr),
 235                                UTF16_HOST_ENDIAN,
 236                                (wchar_t *)out->kvp_ip_val.ip_addr,
 237                                MAX_IP_ADDR_SIZE);
 238                if (len < 0)
 239                        return len;
 240
 241                len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.sub_net,
 242                                strlen((char *)in->body.kvp_ip_val.sub_net),
 243                                UTF16_HOST_ENDIAN,
 244                                (wchar_t *)out->kvp_ip_val.sub_net,
 245                                MAX_IP_ADDR_SIZE);
 246                if (len < 0)
 247                        return len;
 248
 249                len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.gate_way,
 250                                strlen((char *)in->body.kvp_ip_val.gate_way),
 251                                UTF16_HOST_ENDIAN,
 252                                (wchar_t *)out->kvp_ip_val.gate_way,
 253                                MAX_GATEWAY_SIZE);
 254                if (len < 0)
 255                        return len;
 256
 257                len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.dns_addr,
 258                                strlen((char *)in->body.kvp_ip_val.dns_addr),
 259                                UTF16_HOST_ENDIAN,
 260                                (wchar_t *)out->kvp_ip_val.dns_addr,
 261                                MAX_IP_ADDR_SIZE);
 262                if (len < 0)
 263                        return len;
 264
 265                len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.adapter_id,
 266                                strlen((char *)in->body.kvp_ip_val.adapter_id),
 267                                UTF16_HOST_ENDIAN,
 268                                (wchar_t *)out->kvp_ip_val.adapter_id,
 269                                MAX_IP_ADDR_SIZE);
 270                if (len < 0)
 271                        return len;
 272
 273                out->kvp_ip_val.dhcp_enabled =
 274                        in->body.kvp_ip_val.dhcp_enabled;
 275                out->kvp_ip_val.addr_family =
 276                        in->body.kvp_ip_val.addr_family;
 277        }
 278
 279        return 0;
 280}
 281
 282static void process_ib_ipinfo(void *in_msg, void *out_msg, int op)
 283{
 284        struct hv_kvp_ip_msg *in = in_msg;
 285        struct hv_kvp_msg *out = out_msg;
 286
 287        switch (op) {
 288        case KVP_OP_SET_IP_INFO:
 289                /*
 290                 * Transform all parameters into utf8 encoding.
 291                 */
 292                utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.ip_addr,
 293                                MAX_IP_ADDR_SIZE,
 294                                UTF16_LITTLE_ENDIAN,
 295                                (__u8 *)out->body.kvp_ip_val.ip_addr,
 296                                MAX_IP_ADDR_SIZE);
 297
 298                utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.sub_net,
 299                                MAX_IP_ADDR_SIZE,
 300                                UTF16_LITTLE_ENDIAN,
 301                                (__u8 *)out->body.kvp_ip_val.sub_net,
 302                                MAX_IP_ADDR_SIZE);
 303
 304                utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.gate_way,
 305                                MAX_GATEWAY_SIZE,
 306                                UTF16_LITTLE_ENDIAN,
 307                                (__u8 *)out->body.kvp_ip_val.gate_way,
 308                                MAX_GATEWAY_SIZE);
 309
 310                utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.dns_addr,
 311                                MAX_IP_ADDR_SIZE,
 312                                UTF16_LITTLE_ENDIAN,
 313                                (__u8 *)out->body.kvp_ip_val.dns_addr,
 314                                MAX_IP_ADDR_SIZE);
 315
 316                out->body.kvp_ip_val.dhcp_enabled = in->kvp_ip_val.dhcp_enabled;
 317
 318        default:
 319                utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.adapter_id,
 320                                MAX_ADAPTER_ID_SIZE,
 321                                UTF16_LITTLE_ENDIAN,
 322                                (__u8 *)out->body.kvp_ip_val.adapter_id,
 323                                MAX_ADAPTER_ID_SIZE);
 324
 325                out->body.kvp_ip_val.addr_family = in->kvp_ip_val.addr_family;
 326        }
 327}
 328
 329
 330
 331
 332static void
 333kvp_send_key(struct work_struct *dummy)
 334{
 335        struct cn_msg *msg;
 336        struct hv_kvp_msg *message;
 337        struct hv_kvp_msg *in_msg;
 338        __u8 operation = kvp_transaction.kvp_msg->kvp_hdr.operation;
 339        __u8 pool = kvp_transaction.kvp_msg->kvp_hdr.pool;
 340        __u32 val32;
 341        __u64 val64;
 342
 343        msg = kzalloc(sizeof(*msg) + sizeof(struct hv_kvp_msg) , GFP_ATOMIC);
 344        if (!msg)
 345                return;
 346
 347        msg->id.idx =  CN_KVP_IDX;
 348        msg->id.val = CN_KVP_VAL;
 349
 350        message = (struct hv_kvp_msg *)msg->data;
 351        message->kvp_hdr.operation = operation;
 352        message->kvp_hdr.pool = pool;
 353        in_msg = kvp_transaction.kvp_msg;
 354
 355        /*
 356         * The key/value strings sent from the host are encoded in
 357         * in utf16; convert it to utf8 strings.
 358         * The host assures us that the utf16 strings will not exceed
 359         * the max lengths specified. We will however, reserve room
 360         * for the string terminating character - in the utf16s_utf8s()
 361         * function we limit the size of the buffer where the converted
 362         * string is placed to HV_KVP_EXCHANGE_MAX_*_SIZE -1 to gaurantee
 363         * that the strings can be properly terminated!
 364         */
 365
 366        switch (message->kvp_hdr.operation) {
 367        case KVP_OP_SET_IP_INFO:
 368                process_ib_ipinfo(in_msg, message, KVP_OP_SET_IP_INFO);
 369                break;
 370        case KVP_OP_GET_IP_INFO:
 371                process_ib_ipinfo(in_msg, message, KVP_OP_GET_IP_INFO);
 372                break;
 373        case KVP_OP_SET:
 374                switch (in_msg->body.kvp_set.data.value_type) {
 375                case REG_SZ:
 376                        /*
 377                         * The value is a string - utf16 encoding.
 378                         */
 379                        message->body.kvp_set.data.value_size =
 380                                utf16s_to_utf8s(
 381                                (wchar_t *)in_msg->body.kvp_set.data.value,
 382                                in_msg->body.kvp_set.data.value_size,
 383                                UTF16_LITTLE_ENDIAN,
 384                                message->body.kvp_set.data.value,
 385                                HV_KVP_EXCHANGE_MAX_VALUE_SIZE - 1) + 1;
 386                                break;
 387
 388                case REG_U32:
 389                        /*
 390                         * The value is a 32 bit scalar.
 391                         * We save this as a utf8 string.
 392                         */
 393                        val32 = in_msg->body.kvp_set.data.value_u32;
 394                        message->body.kvp_set.data.value_size =
 395                                sprintf(message->body.kvp_set.data.value,
 396                                        "%d", val32) + 1;
 397                        break;
 398
 399                case REG_U64:
 400                        /*
 401                         * The value is a 64 bit scalar.
 402                         * We save this as a utf8 string.
 403                         */
 404                        val64 = in_msg->body.kvp_set.data.value_u64;
 405                        message->body.kvp_set.data.value_size =
 406                                sprintf(message->body.kvp_set.data.value,
 407                                        "%llu", val64) + 1;
 408                        break;
 409
 410                }
 411        case KVP_OP_GET:
 412                message->body.kvp_set.data.key_size =
 413                        utf16s_to_utf8s(
 414                        (wchar_t *)in_msg->body.kvp_set.data.key,
 415                        in_msg->body.kvp_set.data.key_size,
 416                        UTF16_LITTLE_ENDIAN,
 417                        message->body.kvp_set.data.key,
 418                        HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
 419                        break;
 420
 421        case KVP_OP_DELETE:
 422                message->body.kvp_delete.key_size =
 423                        utf16s_to_utf8s(
 424                        (wchar_t *)in_msg->body.kvp_delete.key,
 425                        in_msg->body.kvp_delete.key_size,
 426                        UTF16_LITTLE_ENDIAN,
 427                        message->body.kvp_delete.key,
 428                        HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
 429                        break;
 430
 431        case KVP_OP_ENUMERATE:
 432                message->body.kvp_enum_data.index =
 433                        in_msg->body.kvp_enum_data.index;
 434                        break;
 435        }
 436
 437        msg->len = sizeof(struct hv_kvp_msg);
 438        cn_netlink_send(msg, 0, GFP_ATOMIC);
 439        kfree(msg);
 440
 441        return;
 442}
 443
 444/*
 445 * Send a response back to the host.
 446 */
 447
 448static void
 449kvp_respond_to_host(struct hv_kvp_msg *msg_to_host, int error)
 450{
 451        struct hv_kvp_msg  *kvp_msg;
 452        struct hv_kvp_exchg_msg_value  *kvp_data;
 453        char    *key_name;
 454        char    *value;
 455        struct icmsg_hdr *icmsghdrp;
 456        int     keylen = 0;
 457        int     valuelen = 0;
 458        u32     buf_len;
 459        struct vmbus_channel *channel;
 460        u64     req_id;
 461        int ret;
 462
 463        /*
 464         * If a transaction is not active; log and return.
 465         */
 466
 467        if (!kvp_transaction.active) {
 468                /*
 469                 * This is a spurious call!
 470                 */
 471                pr_warn("KVP: Transaction not active\n");
 472                return;
 473        }
 474        /*
 475         * Copy the global state for completing the transaction. Note that
 476         * only one transaction can be active at a time.
 477         */
 478
 479        buf_len = kvp_transaction.recv_len;
 480        channel = kvp_transaction.recv_channel;
 481        req_id = kvp_transaction.recv_req_id;
 482
 483        kvp_transaction.active = false;
 484
 485        icmsghdrp = (struct icmsg_hdr *)
 486                        &recv_buffer[sizeof(struct vmbuspipe_hdr)];
 487
 488        if (channel->onchannel_callback == NULL)
 489                /*
 490                 * We have raced with util driver being unloaded;
 491                 * silently return.
 492                 */
 493                return;
 494
 495        icmsghdrp->status = error;
 496
 497        /*
 498         * If the error parameter is set, terminate the host's enumeration
 499         * on this pool.
 500         */
 501        if (error) {
 502                /*
 503                 * Something failed or we have timedout;
 504                 * terminate the current host-side iteration.
 505                 */
 506                goto response_done;
 507        }
 508
 509        kvp_msg = (struct hv_kvp_msg *)
 510                        &recv_buffer[sizeof(struct vmbuspipe_hdr) +
 511                        sizeof(struct icmsg_hdr)];
 512
 513        switch (kvp_transaction.kvp_msg->kvp_hdr.operation) {
 514        case KVP_OP_GET_IP_INFO:
 515                ret = process_ob_ipinfo(msg_to_host,
 516                                 (struct hv_kvp_ip_msg *)kvp_msg,
 517                                 KVP_OP_GET_IP_INFO);
 518                if (ret < 0)
 519                        icmsghdrp->status = HV_E_FAIL;
 520
 521                goto response_done;
 522        case KVP_OP_SET_IP_INFO:
 523                goto response_done;
 524        case KVP_OP_GET:
 525                kvp_data = &kvp_msg->body.kvp_get.data;
 526                goto copy_value;
 527
 528        case KVP_OP_SET:
 529        case KVP_OP_DELETE:
 530                goto response_done;
 531
 532        default:
 533                break;
 534        }
 535
 536        kvp_data = &kvp_msg->body.kvp_enum_data.data;
 537        key_name = msg_to_host->body.kvp_enum_data.data.key;
 538
 539        /*
 540         * The windows host expects the key/value pair to be encoded
 541         * in utf16. Ensure that the key/value size reported to the host
 542         * will be less than or equal to the MAX size (including the
 543         * terminating character).
 544         */
 545        keylen = utf8s_to_utf16s(key_name, strlen(key_name), UTF16_HOST_ENDIAN,
 546                                (wchar_t *) kvp_data->key,
 547                                (HV_KVP_EXCHANGE_MAX_KEY_SIZE / 2) - 2);
 548        kvp_data->key_size = 2*(keylen + 1); /* utf16 encoding */
 549
 550copy_value:
 551        value = msg_to_host->body.kvp_enum_data.data.value;
 552        valuelen = utf8s_to_utf16s(value, strlen(value), UTF16_HOST_ENDIAN,
 553                                (wchar_t *) kvp_data->value,
 554                                (HV_KVP_EXCHANGE_MAX_VALUE_SIZE / 2) - 2);
 555        kvp_data->value_size = 2*(valuelen + 1); /* utf16 encoding */
 556
 557        /*
 558         * If the utf8s to utf16s conversion failed; notify host
 559         * of the error.
 560         */
 561        if ((keylen < 0) || (valuelen < 0))
 562                icmsghdrp->status = HV_E_FAIL;
 563
 564        kvp_data->value_type = REG_SZ; /* all our values are strings */
 565
 566response_done:
 567        icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
 568
 569        vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
 570                                VM_PKT_DATA_INBAND, 0);
 571
 572}
 573
 574/*
 575 * This callback is invoked when we get a KVP message from the host.
 576 * The host ensures that only one KVP transaction can be active at a time.
 577 * KVP implementation in Linux needs to forward the key to a user-mde
 578 * component to retrive the corresponding value. Consequently, we cannot
 579 * respond to the host in the conext of this callback. Since the host
 580 * guarantees that at most only one transaction can be active at a time,
 581 * we stash away the transaction state in a set of global variables.
 582 */
 583
 584void hv_kvp_onchannelcallback(void *context)
 585{
 586        struct vmbus_channel *channel = context;
 587        u32 recvlen;
 588        u64 requestid;
 589
 590        struct hv_kvp_msg *kvp_msg;
 591
 592        struct icmsg_hdr *icmsghdrp;
 593        struct icmsg_negotiate *negop = NULL;
 594        int util_fw_version;
 595        int kvp_srv_version;
 596
 597        if (kvp_transaction.active) {
 598                /*
 599                 * We will defer processing this callback once
 600                 * the current transaction is complete.
 601                 */
 602                kvp_transaction.kvp_context = context;
 603                return;
 604        }
 605
 606        vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
 607                         &requestid);
 608
 609        if (recvlen > 0) {
 610                icmsghdrp = (struct icmsg_hdr *)&recv_buffer[
 611                        sizeof(struct vmbuspipe_hdr)];
 612
 613                if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
 614                        /*
 615                         * Based on the host, select appropriate
 616                         * framework and service versions we will
 617                         * negotiate.
 618                         */
 619                        switch (vmbus_proto_version) {
 620                        case (VERSION_WS2008):
 621                                util_fw_version = UTIL_WS2K8_FW_VERSION;
 622                                kvp_srv_version = WS2008_SRV_VERSION;
 623                                break;
 624                        case (VERSION_WIN7):
 625                                util_fw_version = UTIL_FW_VERSION;
 626                                kvp_srv_version = WIN7_SRV_VERSION;
 627                                break;
 628                        default:
 629                                util_fw_version = UTIL_FW_VERSION;
 630                                kvp_srv_version = WIN8_SRV_VERSION;
 631                        }
 632                        vmbus_prep_negotiate_resp(icmsghdrp, negop,
 633                                 recv_buffer, util_fw_version,
 634                                 kvp_srv_version);
 635
 636                } else {
 637                        kvp_msg = (struct hv_kvp_msg *)&recv_buffer[
 638                                sizeof(struct vmbuspipe_hdr) +
 639                                sizeof(struct icmsg_hdr)];
 640
 641                        /*
 642                         * Stash away this global state for completing the
 643                         * transaction; note transactions are serialized.
 644                         */
 645
 646                        kvp_transaction.recv_len = recvlen;
 647                        kvp_transaction.recv_channel = channel;
 648                        kvp_transaction.recv_req_id = requestid;
 649                        kvp_transaction.active = true;
 650                        kvp_transaction.kvp_msg = kvp_msg;
 651
 652                        /*
 653                         * Get the information from the
 654                         * user-mode component.
 655                         * component. This transaction will be
 656                         * completed when we get the value from
 657                         * the user-mode component.
 658                         * Set a timeout to deal with
 659                         * user-mode not responding.
 660                         */
 661                        schedule_work(&kvp_sendkey_work);
 662                        schedule_delayed_work(&kvp_work, 5*HZ);
 663
 664                        return;
 665
 666                }
 667
 668                icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
 669                        | ICMSGHDRFLAG_RESPONSE;
 670
 671                vmbus_sendpacket(channel, recv_buffer,
 672                                       recvlen, requestid,
 673                                       VM_PKT_DATA_INBAND, 0);
 674        }
 675
 676}
 677
 678int
 679hv_kvp_init(struct hv_util_service *srv)
 680{
 681        int err;
 682
 683        err = cn_add_callback(&kvp_id, kvp_name, kvp_cn_callback);
 684        if (err)
 685                return err;
 686        recv_buffer = srv->recv_buffer;
 687
 688        /*
 689         * When this driver loads, the user level daemon that
 690         * processes the host requests may not yet be running.
 691         * Defer processing channel callbacks until the daemon
 692         * has registered.
 693         */
 694        kvp_transaction.active = true;
 695
 696        return 0;
 697}
 698
 699void hv_kvp_deinit(void)
 700{
 701        cn_del_callback(&kvp_id);
 702        cancel_delayed_work_sync(&kvp_work);
 703        cancel_work_sync(&kvp_sendkey_work);
 704}
 705
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