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 <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 #include "hyperv_vmbus.h"
  32 #include "hv_utils_transport.h"
  33
  34 /*
  35  * Pre win8 version numbers used in ws2008 and ws 2008 r2 (win7)
  36  */
  37 #define WS2008_SRV_MAJOR        1
  38 #define WS2008_SRV_MINOR        0
  39 #define WS2008_SRV_VERSION     (WS2008_SRV_MAJOR << 16 | WS2008_SRV_MINOR)
  40
  41 #define WIN7_SRV_MAJOR   3
  42 #define WIN7_SRV_MINOR   0
  43 #define WIN7_SRV_VERSION     (WIN7_SRV_MAJOR << 16 | WIN7_SRV_MINOR)
  44
  45 #define WIN8_SRV_MAJOR   4
  46 #define WIN8_SRV_MINOR   0
  47 #define WIN8_SRV_VERSION     (WIN8_SRV_MAJOR << 16 | WIN8_SRV_MINOR)
  48
  49 #define KVP_VER_COUNT 3
  50 static const int kvp_versions[] = {
  51         WIN8_SRV_VERSION,
  52         WIN7_SRV_VERSION,
  53         WS2008_SRV_VERSION
  54 };
  55
  56 #define FW_VER_COUNT 2
  57 static const int fw_versions[] = {
  58         UTIL_FW_VERSION,
  59         UTIL_WS2K8_FW_VERSION
  60 };
  61
  62 /*
  63  * Global state maintained for transaction that is being processed. For a class
  64  * of integration services, including the "KVP service", the specified protocol
  65  * is a "request/response" protocol which means that there can only be single
  66  * outstanding transaction from the host at any given point in time. We use
  67  * this to simplify memory management in this driver - we cache and process
  68  * only one message at a time.
  69  *
  70  * While the request/response protocol is guaranteed by the host, we further
  71  * ensure this by serializing packet processing in this driver - we do not
  72  * read additional packets from the VMBUs until the current packet is fully
  73  * handled.
  74  */
  75
  76 static struct {
  77         int state;   /* hvutil_device_state */
  78         int recv_len; /* number of bytes received. */
  79         struct hv_kvp_msg  *kvp_msg; /* current message */
  80         struct vmbus_channel *recv_channel; /* chn we got the request */
  81         u64 recv_req_id; /* request ID. */
  82 } kvp_transaction;
  83
  84 /*
  85  * This state maintains the version number registered by the daemon.
  86  */
  87 static int dm_reg_value;
  88
  89 static void kvp_send_key(struct work_struct *dummy);
  90
  91
  92 static void kvp_respond_to_host(struct hv_kvp_msg *msg, int error);
  93 static void kvp_timeout_func(struct work_struct *dummy);
  94 static void kvp_host_handshake_func(struct work_struct *dummy);
  95 static void kvp_register(int);
  96
  97 static DECLARE_DELAYED_WORK(kvp_timeout_work, kvp_timeout_func);
  98 static DECLARE_DELAYED_WORK(kvp_host_handshake_work, kvp_host_handshake_func);
  99 static DECLARE_WORK(kvp_sendkey_work, kvp_send_key);
 100
 101 static const char kvp_devname[] = "vmbus/hv_kvp";
 102 static u8 *recv_buffer;
 103 static struct hvutil_transport *hvt;
 104 /*
 105  * Register the kernel component with the user-level daemon.
 106  * As part of this registration, pass the LIC version number.
 107  * This number has no meaning, it satisfies the registration protocol.
 108  */
 109 #define HV_DRV_VERSION           "3.1"
 110
 111 static void kvp_poll_wrapper(void *channel)
 112 {
 113         /* Transaction is finished, reset the state here to avoid races. */
 114         kvp_transaction.state = HVUTIL_READY;
 115         hv_kvp_onchannelcallback(channel);
 116 }
 117
 118 static void kvp_register_done(void)
 119 {
 120         /*
 121          * If we're still negotiating with the host cancel the timeout
 122          * work to not poll the channel twice.
 123          */
 124         pr_debug("KVP: userspace daemon registered\n");
 125         cancel_delayed_work_sync(&kvp_host_handshake_work);
 126         hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
 127 }
 128
 129 static void
 130 kvp_register(int reg_value)
 131 {
 132
 133         struct hv_kvp_msg *kvp_msg;
 134         char *version;
 135
 136         kvp_msg = kzalloc(sizeof(*kvp_msg), GFP_KERNEL);
 137
 138         if (kvp_msg) {
 139                 version = kvp_msg->body.kvp_register.version;
 140                 kvp_msg->kvp_hdr.operation = reg_value;
 141                 strcpy(version, HV_DRV_VERSION);
 142
 143                 hvutil_transport_send(hvt, kvp_msg, sizeof(*kvp_msg),
 144                                       kvp_register_done);
 145                 kfree(kvp_msg);
 146         }
 147 }
 148
 149 static void kvp_timeout_func(struct work_struct *dummy)
 150 {
 151         /*
 152          * If the timer fires, the user-mode component has not responded;
 153          * process the pending transaction.
 154          */
 155         kvp_respond_to_host(NULL, HV_E_FAIL);
 156
 157         hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
 158 }
 159
 160 static void kvp_host_handshake_func(struct work_struct *dummy)
 161 {
 162         hv_poll_channel(kvp_transaction.recv_channel, hv_kvp_onchannelcallback);
 163 }
 164
 165 static int kvp_handle_handshake(struct hv_kvp_msg *msg)
 166 {
 167         switch (msg->kvp_hdr.operation) {
 168         case KVP_OP_REGISTER:
 169                 dm_reg_value = KVP_OP_REGISTER;
 170                 pr_info("KVP: IP injection functionality not available\n");
 171                 pr_info("KVP: Upgrade the KVP daemon\n");
 172                 break;
 173         case KVP_OP_REGISTER1:
 174                 dm_reg_value = KVP_OP_REGISTER1;
 175                 break;
 176         default:
 177                 pr_info("KVP: incompatible daemon\n");
 178                 pr_info("KVP: KVP version: %d, Daemon version: %d\n",
 179                         KVP_OP_REGISTER1, msg->kvp_hdr.operation);
 180                 return -EINVAL;
 181         }
 182
 183         /*
 184          * We have a compatible daemon; complete the handshake.
 185          */
 186         pr_debug("KVP: userspace daemon ver. %d connected\n",
 187                  msg->kvp_hdr.operation);
 188         kvp_register(dm_reg_value);
 189
 190         return 0;
 191 }
 192
 193
 194 /*
 195  * Callback when data is received from user mode.
 196  */
 197
 198 static int kvp_on_msg(void *msg, int len)
 199 {
 200         struct hv_kvp_msg *message = (struct hv_kvp_msg *)msg;
 201         struct hv_kvp_msg_enumerate *data;
 202         int     error = 0;
 203
 204         if (len < sizeof(*message))
 205                 return -EINVAL;
 206
 207         /*
 208          * If we are negotiating the version information
 209          * with the daemon; handle that first.
 210          */
 211
 212         if (kvp_transaction.state < HVUTIL_READY) {
 213                 return kvp_handle_handshake(message);
 214         }
 215
 216         /* We didn't send anything to userspace so the reply is spurious */
 217         if (kvp_transaction.state < HVUTIL_USERSPACE_REQ)
 218                 return -EINVAL;
 219
 220         kvp_transaction.state = HVUTIL_USERSPACE_RECV;
 221
 222         /*
 223          * Based on the version of the daemon, we propagate errors from the
 224          * daemon differently.
 225          */
 226
 227         data = &message->body.kvp_enum_data;
 228
 229         switch (dm_reg_value) {
 230         case KVP_OP_REGISTER:
 231                 /*
 232                  * Null string is used to pass back error condition.
 233                  */
 234                 if (data->data.key[0] == 0)
 235                         error = HV_S_CONT;
 236                 break;
 237
 238         case KVP_OP_REGISTER1:
 239                 /*
 240                  * We use the message header information from
 241                  * the user level daemon to transmit errors.
 242                  */
 243                 error = message->error;
 244                 break;
 245         }
 246
 247         /*
 248          * Complete the transaction by forwarding the key value
 249          * to the host. But first, cancel the timeout.
 250          */
 251         if (cancel_delayed_work_sync(&kvp_timeout_work)) {
 252                 kvp_respond_to_host(message, error);
 253                 hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
 254         }
 255
 256         return 0;
 257 }
 258
 259
 260 static int process_ob_ipinfo(void *in_msg, void *out_msg, int op)
 261 {
 262         struct hv_kvp_msg *in = in_msg;
 263         struct hv_kvp_ip_msg *out = out_msg;
 264         int len;
 265
 266         switch (op) {
 267         case KVP_OP_GET_IP_INFO:
 268                 /*
 269                  * Transform all parameters into utf16 encoding.
 270                  */
 271                 len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.ip_addr,
 272                                 strlen((char *)in->body.kvp_ip_val.ip_addr),
 273                                 UTF16_HOST_ENDIAN,
 274                                 (wchar_t *)out->kvp_ip_val.ip_addr,
 275                                 MAX_IP_ADDR_SIZE);
 276                 if (len < 0)
 277                         return len;
 278
 279                 len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.sub_net,
 280                                 strlen((char *)in->body.kvp_ip_val.sub_net),
 281                                 UTF16_HOST_ENDIAN,
 282                                 (wchar_t *)out->kvp_ip_val.sub_net,
 283                                 MAX_IP_ADDR_SIZE);
 284                 if (len < 0)
 285                         return len;
 286
 287                 len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.gate_way,
 288                                 strlen((char *)in->body.kvp_ip_val.gate_way),
 289                                 UTF16_HOST_ENDIAN,
 290                                 (wchar_t *)out->kvp_ip_val.gate_way,
 291                                 MAX_GATEWAY_SIZE);
 292                 if (len < 0)
 293                         return len;
 294
 295                 len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.dns_addr,
 296                                 strlen((char *)in->body.kvp_ip_val.dns_addr),
 297                                 UTF16_HOST_ENDIAN,
 298                                 (wchar_t *)out->kvp_ip_val.dns_addr,
 299                                 MAX_IP_ADDR_SIZE);
 300                 if (len < 0)
 301                         return len;
 302
 303                 len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.adapter_id,
 304                                 strlen((char *)in->body.kvp_ip_val.adapter_id),
 305                                 UTF16_HOST_ENDIAN,
 306                                 (wchar_t *)out->kvp_ip_val.adapter_id,
 307                                 MAX_IP_ADDR_SIZE);
 308                 if (len < 0)
 309                         return len;
 310
 311                 out->kvp_ip_val.dhcp_enabled =
 312                         in->body.kvp_ip_val.dhcp_enabled;
 313                 out->kvp_ip_val.addr_family =
 314                         in->body.kvp_ip_val.addr_family;
 315         }
 316
 317         return 0;
 318 }
 319
 320 static void process_ib_ipinfo(void *in_msg, void *out_msg, int op)
 321 {
 322         struct hv_kvp_ip_msg *in = in_msg;
 323         struct hv_kvp_msg *out = out_msg;
 324
 325         switch (op) {
 326         case KVP_OP_SET_IP_INFO:
 327                 /*
 328                  * Transform all parameters into utf8 encoding.
 329                  */
 330                 utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.ip_addr,
 331                                 MAX_IP_ADDR_SIZE,
 332                                 UTF16_LITTLE_ENDIAN,
 333                                 (__u8 *)out->body.kvp_ip_val.ip_addr,
 334                                 MAX_IP_ADDR_SIZE);
 335
 336                 utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.sub_net,
 337                                 MAX_IP_ADDR_SIZE,
 338                                 UTF16_LITTLE_ENDIAN,
 339                                 (__u8 *)out->body.kvp_ip_val.sub_net,
 340                                 MAX_IP_ADDR_SIZE);
 341
 342                 utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.gate_way,
 343                                 MAX_GATEWAY_SIZE,
 344                                 UTF16_LITTLE_ENDIAN,
 345                                 (__u8 *)out->body.kvp_ip_val.gate_way,
 346                                 MAX_GATEWAY_SIZE);
 347
 348                 utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.dns_addr,
 349                                 MAX_IP_ADDR_SIZE,
 350                                 UTF16_LITTLE_ENDIAN,
 351                                 (__u8 *)out->body.kvp_ip_val.dns_addr,
 352                                 MAX_IP_ADDR_SIZE);
 353
 354                 out->body.kvp_ip_val.dhcp_enabled = in->kvp_ip_val.dhcp_enabled;
 355
 356         default:
 357                 utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.adapter_id,
 358                                 MAX_ADAPTER_ID_SIZE,
 359                                 UTF16_LITTLE_ENDIAN,
 360                                 (__u8 *)out->body.kvp_ip_val.adapter_id,
 361                                 MAX_ADAPTER_ID_SIZE);
 362
 363                 out->body.kvp_ip_val.addr_family = in->kvp_ip_val.addr_family;
 364         }
 365 }
 366
 367
 368
 369
 370 static void
 371 kvp_send_key(struct work_struct *dummy)
 372 {
 373         struct hv_kvp_msg *message;
 374         struct hv_kvp_msg *in_msg;
 375         __u8 operation = kvp_transaction.kvp_msg->kvp_hdr.operation;
 376         __u8 pool = kvp_transaction.kvp_msg->kvp_hdr.pool;
 377         __u32 val32;
 378         __u64 val64;
 379         int rc;
 380
 381         /* The transaction state is wrong. */
 382         if (kvp_transaction.state != HVUTIL_HOSTMSG_RECEIVED)
 383                 return;
 384
 385         message = kzalloc(sizeof(*message), GFP_KERNEL);
 386         if (!message)
 387                 return;
 388
 389         message->kvp_hdr.operation = operation;
 390         message->kvp_hdr.pool = pool;
 391         in_msg = kvp_transaction.kvp_msg;
 392
 393         /*
 394          * The key/value strings sent from the host are encoded in
 395          * in utf16; convert it to utf8 strings.
 396          * The host assures us that the utf16 strings will not exceed
 397          * the max lengths specified. We will however, reserve room
 398          * for the string terminating character - in the utf16s_utf8s()
 399          * function we limit the size of the buffer where the converted
 400          * string is placed to HV_KVP_EXCHANGE_MAX_*_SIZE -1 to gaurantee
 401          * that the strings can be properly terminated!
 402          */
 403
 404         switch (message->kvp_hdr.operation) {
 405         case KVP_OP_SET_IP_INFO:
 406                 process_ib_ipinfo(in_msg, message, KVP_OP_SET_IP_INFO);
 407                 break;
 408         case KVP_OP_GET_IP_INFO:
 409                 process_ib_ipinfo(in_msg, message, KVP_OP_GET_IP_INFO);
 410                 break;
 411         case KVP_OP_SET:
 412                 switch (in_msg->body.kvp_set.data.value_type) {
 413                 case REG_SZ:
 414                         /*
 415                          * The value is a string - utf16 encoding.
 416                          */
 417                         message->body.kvp_set.data.value_size =
 418                                 utf16s_to_utf8s(
 419                                 (wchar_t *)in_msg->body.kvp_set.data.value,
 420                                 in_msg->body.kvp_set.data.value_size,
 421                                 UTF16_LITTLE_ENDIAN,
 422                                 message->body.kvp_set.data.value,
 423                                 HV_KVP_EXCHANGE_MAX_VALUE_SIZE - 1) + 1;
 424                                 break;
 425
 426                 case REG_U32:
 427                         /*
 428                          * The value is a 32 bit scalar.
 429                          * We save this as a utf8 string.
 430                          */
 431                         val32 = in_msg->body.kvp_set.data.value_u32;
 432                         message->body.kvp_set.data.value_size =
 433                                 sprintf(message->body.kvp_set.data.value,
 434                                         "%d", val32) + 1;
 435                         break;
 436
 437                 case REG_U64:
 438                         /*
 439                          * The value is a 64 bit scalar.
 440                          * We save this as a utf8 string.
 441                          */
 442                         val64 = in_msg->body.kvp_set.data.value_u64;
 443                         message->body.kvp_set.data.value_size =
 444                                 sprintf(message->body.kvp_set.data.value,
 445                                         "%llu", val64) + 1;
 446                         break;
 447
 448                 }
 449         case KVP_OP_GET:
 450                 message->body.kvp_set.data.key_size =
 451                         utf16s_to_utf8s(
 452                         (wchar_t *)in_msg->body.kvp_set.data.key,
 453                         in_msg->body.kvp_set.data.key_size,
 454                         UTF16_LITTLE_ENDIAN,
 455                         message->body.kvp_set.data.key,
 456                         HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
 457                         break;
 458
 459         case KVP_OP_DELETE:
 460                 message->body.kvp_delete.key_size =
 461                         utf16s_to_utf8s(
 462                         (wchar_t *)in_msg->body.kvp_delete.key,
 463                         in_msg->body.kvp_delete.key_size,
 464                         UTF16_LITTLE_ENDIAN,
 465                         message->body.kvp_delete.key,
 466                         HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
 467                         break;
 468
 469         case KVP_OP_ENUMERATE:
 470                 message->body.kvp_enum_data.index =
 471                         in_msg->body.kvp_enum_data.index;
 472                         break;
 473         }
 474
 475         kvp_transaction.state = HVUTIL_USERSPACE_REQ;
 476         rc = hvutil_transport_send(hvt, message, sizeof(*message), NULL);
 477         if (rc) {
 478                 pr_debug("KVP: failed to communicate to the daemon: %d\n", rc);
 479                 if (cancel_delayed_work_sync(&kvp_timeout_work)) {
 480                         kvp_respond_to_host(message, HV_E_FAIL);
 481                         kvp_transaction.state = HVUTIL_READY;
 482                 }
 483         }
 484
 485         kfree(message);
 486
 487         return;
 488 }
 489
 490 /*
 491  * Send a response back to the host.
 492  */
 493
 494 static void
 495 kvp_respond_to_host(struct hv_kvp_msg *msg_to_host, int error)
 496 {
 497         struct hv_kvp_msg  *kvp_msg;
 498         struct hv_kvp_exchg_msg_value  *kvp_data;
 499         char    *key_name;
 500         char    *value;
 501         struct icmsg_hdr *icmsghdrp;
 502         int     keylen = 0;
 503         int     valuelen = 0;
 504         u32     buf_len;
 505         struct vmbus_channel *channel;
 506         u64     req_id;
 507         int ret;
 508
 509         /*
 510          * Copy the global state for completing the transaction. Note that
 511          * only one transaction can be active at a time.
 512          */
 513
 514         buf_len = kvp_transaction.recv_len;
 515         channel = kvp_transaction.recv_channel;
 516         req_id = kvp_transaction.recv_req_id;
 517
 518         icmsghdrp = (struct icmsg_hdr *)
 519                         &recv_buffer[sizeof(struct vmbuspipe_hdr)];
 520
 521         if (channel->onchannel_callback == NULL)
 522                 /*
 523                  * We have raced with util driver being unloaded;
 524                  * silently return.
 525                  */
 526                 return;
 527
 528         icmsghdrp->status = error;
 529
 530         /*
 531          * If the error parameter is set, terminate the host's enumeration
 532          * on this pool.
 533          */
 534         if (error) {
 535                 /*
 536                  * Something failed or we have timedout;
 537                  * terminate the current host-side iteration.
 538                  */
 539                 goto response_done;
 540         }
 541
 542         kvp_msg = (struct hv_kvp_msg *)
 543                         &recv_buffer[sizeof(struct vmbuspipe_hdr) +
 544                         sizeof(struct icmsg_hdr)];
 545
 546         switch (kvp_transaction.kvp_msg->kvp_hdr.operation) {
 547         case KVP_OP_GET_IP_INFO:
 548                 ret = process_ob_ipinfo(msg_to_host,
 549                                  (struct hv_kvp_ip_msg *)kvp_msg,
 550                                  KVP_OP_GET_IP_INFO);
 551                 if (ret < 0)
 552                         icmsghdrp->status = HV_E_FAIL;
 553
 554                 goto response_done;
 555         case KVP_OP_SET_IP_INFO:
 556                 goto response_done;
 557         case KVP_OP_GET:
 558                 kvp_data = &kvp_msg->body.kvp_get.data;
 559                 goto copy_value;
 560
 561         case KVP_OP_SET:
 562         case KVP_OP_DELETE:
 563                 goto response_done;
 564
 565         default:
 566                 break;
 567         }
 568
 569         kvp_data = &kvp_msg->body.kvp_enum_data.data;
 570         key_name = msg_to_host->body.kvp_enum_data.data.key;
 571
 572         /*
 573          * The windows host expects the key/value pair to be encoded
 574          * in utf16. Ensure that the key/value size reported to the host
 575          * will be less than or equal to the MAX size (including the
 576          * terminating character).
 577          */
 578         keylen = utf8s_to_utf16s(key_name, strlen(key_name), UTF16_HOST_ENDIAN,
 579                                 (wchar_t *) kvp_data->key,
 580                                 (HV_KVP_EXCHANGE_MAX_KEY_SIZE / 2) - 2);
 581         kvp_data->key_size = 2*(keylen + 1); /* utf16 encoding */
 582
 583 copy_value:
 584         value = msg_to_host->body.kvp_enum_data.data.value;
 585         valuelen = utf8s_to_utf16s(value, strlen(value), UTF16_HOST_ENDIAN,
 586                                 (wchar_t *) kvp_data->value,
 587                                 (HV_KVP_EXCHANGE_MAX_VALUE_SIZE / 2) - 2);
 588         kvp_data->value_size = 2*(valuelen + 1); /* utf16 encoding */
 589
 590         /*
 591          * If the utf8s to utf16s conversion failed; notify host
 592          * of the error.
 593          */
 594         if ((keylen < 0) || (valuelen < 0))
 595                 icmsghdrp->status = HV_E_FAIL;
 596
 597         kvp_data->value_type = REG_SZ; /* all our values are strings */
 598
 599 response_done:
 600         icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
 601
 602         vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
 603                                 VM_PKT_DATA_INBAND, 0);
 604 }
 605
 606 /*
 607  * This callback is invoked when we get a KVP message from the host.
 608  * The host ensures that only one KVP transaction can be active at a time.
 609  * KVP implementation in Linux needs to forward the key to a user-mde
 610  * component to retrive the corresponding value. Consequently, we cannot
 611  * respond to the host in the conext of this callback. Since the host
 612  * guarantees that at most only one transaction can be active at a time,
 613  * we stash away the transaction state in a set of global variables.
 614  */
 615
 616 void hv_kvp_onchannelcallback(void *context)
 617 {
 618         struct vmbus_channel *channel = context;
 619         u32 recvlen;
 620         u64 requestid;
 621
 622         struct hv_kvp_msg *kvp_msg;
 623
 624         struct icmsg_hdr *icmsghdrp;
 625         int kvp_srv_version;
 626         static enum {NEGO_NOT_STARTED,
 627                      NEGO_IN_PROGRESS,
 628                      NEGO_FINISHED} host_negotiatied = NEGO_NOT_STARTED;
 629
 630         if (host_negotiatied == NEGO_NOT_STARTED &&
 631             kvp_transaction.state < HVUTIL_READY) {
 632                 /*
 633                  * If userspace daemon is not connected and host is asking
 634                  * us to negotiate we need to delay to not lose messages.
 635                  * This is important for Failover IP setting.
 636                  */
 637                 host_negotiatied = NEGO_IN_PROGRESS;
 638                 schedule_delayed_work(&kvp_host_handshake_work,
 639                                       HV_UTIL_NEGO_TIMEOUT * HZ);
 640                 return;
 641         }
 642         if (kvp_transaction.state > HVUTIL_READY)
 643                 return;
 644
 645         vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 4, &recvlen,
 646                          &requestid);
 647
 648         if (recvlen > 0) {
 649                 icmsghdrp = (struct icmsg_hdr *)&recv_buffer[
 650                         sizeof(struct vmbuspipe_hdr)];
 651
 652                 if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
 653                         if (vmbus_prep_negotiate_resp(icmsghdrp,
 654                                  recv_buffer, fw_versions, FW_VER_COUNT,
 655                                  kvp_versions, KVP_VER_COUNT,
 656                                  NULL, &kvp_srv_version)) {
 657                                 pr_info("KVP IC version %d.%d\n",
 658                                         kvp_srv_version >> 16,
 659                                         kvp_srv_version & 0xFFFF);
 660                         }
 661                 } else {
 662                         kvp_msg = (struct hv_kvp_msg *)&recv_buffer[
 663                                 sizeof(struct vmbuspipe_hdr) +
 664                                 sizeof(struct icmsg_hdr)];
 665
 666                         /*
 667                          * Stash away this global state for completing the
 668                          * transaction; note transactions are serialized.
 669                          */
 670
 671                         kvp_transaction.recv_len = recvlen;
 672                         kvp_transaction.recv_req_id = requestid;
 673                         kvp_transaction.kvp_msg = kvp_msg;
 674
 675                         if (kvp_transaction.state < HVUTIL_READY) {
 676                                 /* Userspace is not registered yet */
 677                                 kvp_respond_to_host(NULL, HV_E_FAIL);
 678                                 return;
 679                         }
 680                         kvp_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
 681
 682                         /*
 683                          * Get the information from the
 684                          * user-mode component.
 685                          * component. This transaction will be
 686                          * completed when we get the value from
 687                          * the user-mode component.
 688                          * Set a timeout to deal with
 689                          * user-mode not responding.
 690                          */
 691                         schedule_work(&kvp_sendkey_work);
 692                         schedule_delayed_work(&kvp_timeout_work,
 693                                               HV_UTIL_TIMEOUT * HZ);
 694
 695                         return;
 696
 697                 }
 698
 699                 icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
 700                         | ICMSGHDRFLAG_RESPONSE;
 701
 702                 vmbus_sendpacket(channel, recv_buffer,
 703                                        recvlen, requestid,
 704                                        VM_PKT_DATA_INBAND, 0);
 705
 706                 host_negotiatied = NEGO_FINISHED;
 707         }
 708
 709 }
 710
 711 static void kvp_on_reset(void)
 712 {
 713         if (cancel_delayed_work_sync(&kvp_timeout_work))
 714                 kvp_respond_to_host(NULL, HV_E_FAIL);
 715         kvp_transaction.state = HVUTIL_DEVICE_INIT;
 716 }
 717
 718 int
 719 hv_kvp_init(struct hv_util_service *srv)
 720 {
 721         recv_buffer = srv->recv_buffer;
 722         kvp_transaction.recv_channel = srv->channel;
 723
 724         /*
 725          * When this driver loads, the user level daemon that
 726          * processes the host requests may not yet be running.
 727          * Defer processing channel callbacks until the daemon
 728          * has registered.
 729          */
 730         kvp_transaction.state = HVUTIL_DEVICE_INIT;
 731
 732         hvt = hvutil_transport_init(kvp_devname, CN_KVP_IDX, CN_KVP_VAL,
 733                                     kvp_on_msg, kvp_on_reset);
 734         if (!hvt)
 735                 return -EFAULT;
 736
 737         return 0;
 738 }
 739
 740 void hv_kvp_deinit(void)
 741 {
 742         kvp_transaction.state = HVUTIL_DEVICE_DYING;
 743         cancel_delayed_work_sync(&kvp_host_handshake_work);
 744         cancel_delayed_work_sync(&kvp_timeout_work);
 745         cancel_work_sync(&kvp_sendkey_work);
 746         hvutil_transport_destroy(hvt);
 747 }