Home Home > GIT Browse
summaryrefslogtreecommitdiff
blob: 5054d1105236e15b3ec3912026fd08ae3bc99044 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
/*
 * An implementation of key value pair (KVP) functionality for Linux.
 *
 *
 * Copyright (C) 2010, Novell, Inc.
 * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 * NON INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/net.h>
#include <linux/nls.h>
#include <linux/connector.h>
#include <linux/workqueue.h>
#include <linux/hyperv.h>

#include "hyperv_vmbus.h"
#include "hv_utils_transport.h"

/*
 * Pre win8 version numbers used in ws2008 and ws 2008 r2 (win7)
 */
#define WS2008_SRV_MAJOR	1
#define WS2008_SRV_MINOR	0
#define WS2008_SRV_VERSION     (WS2008_SRV_MAJOR << 16 | WS2008_SRV_MINOR)

#define WIN7_SRV_MAJOR   3
#define WIN7_SRV_MINOR   0
#define WIN7_SRV_VERSION     (WIN7_SRV_MAJOR << 16 | WIN7_SRV_MINOR)

#define WIN8_SRV_MAJOR   4
#define WIN8_SRV_MINOR   0
#define WIN8_SRV_VERSION     (WIN8_SRV_MAJOR << 16 | WIN8_SRV_MINOR)

#define KVP_VER_COUNT 3
static const int kvp_versions[] = {
	WIN8_SRV_VERSION,
	WIN7_SRV_VERSION,
	WS2008_SRV_VERSION
};

#define FW_VER_COUNT 2
static const int fw_versions[] = {
	UTIL_FW_VERSION,
	UTIL_WS2K8_FW_VERSION
};

/*
 * Global state maintained for transaction that is being processed. For a class
 * of integration services, including the "KVP service", the specified protocol
 * is a "request/response" protocol which means that there can only be single
 * outstanding transaction from the host at any given point in time. We use
 * this to simplify memory management in this driver - we cache and process
 * only one message at a time.
 *
 * While the request/response protocol is guaranteed by the host, we further
 * ensure this by serializing packet processing in this driver - we do not
 * read additional packets from the VMBUS until the current packet is fully
 * handled.
 */

static struct {
	int state;   /* hvutil_device_state */
	int recv_len; /* number of bytes received. */
	struct hv_kvp_msg  *kvp_msg; /* current message */
	struct vmbus_channel *recv_channel; /* chn we got the request */
	u64 recv_req_id; /* request ID. */
} kvp_transaction;

/*
 * This state maintains the version number registered by the daemon.
 */
static int dm_reg_value;

static void kvp_send_key(struct work_struct *dummy);


static void kvp_respond_to_host(struct hv_kvp_msg *msg, int error);
static void kvp_timeout_func(struct work_struct *dummy);
static void kvp_host_handshake_func(struct work_struct *dummy);
static void kvp_register(int);

static DECLARE_DELAYED_WORK(kvp_timeout_work, kvp_timeout_func);
static DECLARE_DELAYED_WORK(kvp_host_handshake_work, kvp_host_handshake_func);
static DECLARE_WORK(kvp_sendkey_work, kvp_send_key);

static const char kvp_devname[] = "vmbus/hv_kvp";
static u8 *recv_buffer;
static struct hvutil_transport *hvt;
/*
 * Register the kernel component with the user-level daemon.
 * As part of this registration, pass the LIC version number.
 * This number has no meaning, it satisfies the registration protocol.
 */
#define HV_DRV_VERSION           "3.1"

static void kvp_poll_wrapper(void *channel)
{
	/* Transaction is finished, reset the state here to avoid races. */
	kvp_transaction.state = HVUTIL_READY;
	tasklet_schedule(&((struct vmbus_channel *)channel)->callback_event);
}

static void kvp_register_done(void)
{
	/*
	 * If we're still negotiating with the host cancel the timeout
	 * work to not poll the channel twice.
	 */
	pr_debug("KVP: userspace daemon registered\n");
	cancel_delayed_work_sync(&kvp_host_handshake_work);
	hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
}

static void
kvp_register(int reg_value)
{

	struct hv_kvp_msg *kvp_msg;
	char *version;

	kvp_msg = kzalloc(sizeof(*kvp_msg), GFP_KERNEL);

	if (kvp_msg) {
		version = kvp_msg->body.kvp_register.version;
		kvp_msg->kvp_hdr.operation = reg_value;
		strcpy(version, HV_DRV_VERSION);

		hvutil_transport_send(hvt, kvp_msg, sizeof(*kvp_msg),
				      kvp_register_done);
		kfree(kvp_msg);
	}
}

static void kvp_timeout_func(struct work_struct *dummy)
{
	/*
	 * If the timer fires, the user-mode component has not responded;
	 * process the pending transaction.
	 */
	kvp_respond_to_host(NULL, HV_E_FAIL);

	hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
}

static void kvp_host_handshake_func(struct work_struct *dummy)
{
	tasklet_schedule(&kvp_transaction.recv_channel->callback_event);
}

static int kvp_handle_handshake(struct hv_kvp_msg *msg)
{
	switch (msg->kvp_hdr.operation) {
	case KVP_OP_REGISTER:
		dm_reg_value = KVP_OP_REGISTER;
		pr_info("KVP: IP injection functionality not available\n");
		pr_info("KVP: Upgrade the KVP daemon\n");
		break;
	case KVP_OP_REGISTER1:
		dm_reg_value = KVP_OP_REGISTER1;
		break;
	default:
		pr_info("KVP: incompatible daemon\n");
		pr_info("KVP: KVP version: %d, Daemon version: %d\n",
			KVP_OP_REGISTER1, msg->kvp_hdr.operation);
		return -EINVAL;
	}

	/*
	 * We have a compatible daemon; complete the handshake.
	 */
	pr_debug("KVP: userspace daemon ver. %d connected\n",
		 msg->kvp_hdr.operation);
	kvp_register(dm_reg_value);

	return 0;
}


/*
 * Callback when data is received from user mode.
 */

static int kvp_on_msg(void *msg, int len)
{
	struct hv_kvp_msg *message = (struct hv_kvp_msg *)msg;
	struct hv_kvp_msg_enumerate *data;
	int	error = 0;

	if (len < sizeof(*message))
		return -EINVAL;

	/*
	 * If we are negotiating the version information
	 * with the daemon; handle that first.
	 */

	if (kvp_transaction.state < HVUTIL_READY) {
		return kvp_handle_handshake(message);
	}

	/* We didn't send anything to userspace so the reply is spurious */
	if (kvp_transaction.state < HVUTIL_USERSPACE_REQ)
		return -EINVAL;

	kvp_transaction.state = HVUTIL_USERSPACE_RECV;

	/*
	 * Based on the version of the daemon, we propagate errors from the
	 * daemon differently.
	 */

	data = &message->body.kvp_enum_data;

	switch (dm_reg_value) {
	case KVP_OP_REGISTER:
		/*
		 * Null string is used to pass back error condition.
		 */
		if (data->data.key[0] == 0)
			error = HV_S_CONT;
		break;

	case KVP_OP_REGISTER1:
		/*
		 * We use the message header information from
		 * the user level daemon to transmit errors.
		 */
		error = message->error;
		break;
	}

	/*
	 * Complete the transaction by forwarding the key value
	 * to the host. But first, cancel the timeout.
	 */
	if (cancel_delayed_work_sync(&kvp_timeout_work)) {
		kvp_respond_to_host(message, error);
		hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
	}

	return 0;
}


static int process_ob_ipinfo(void *in_msg, void *out_msg, int op)
{
	struct hv_kvp_msg *in = in_msg;
	struct hv_kvp_ip_msg *out = out_msg;
	int len;

	switch (op) {
	case KVP_OP_GET_IP_INFO:
		/*
		 * Transform all parameters into utf16 encoding.
		 */
		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.ip_addr,
				strlen((char *)in->body.kvp_ip_val.ip_addr),
				UTF16_HOST_ENDIAN,
				(wchar_t *)out->kvp_ip_val.ip_addr,
				MAX_IP_ADDR_SIZE);
		if (len < 0)
			return len;

		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.sub_net,
				strlen((char *)in->body.kvp_ip_val.sub_net),
				UTF16_HOST_ENDIAN,
				(wchar_t *)out->kvp_ip_val.sub_net,
				MAX_IP_ADDR_SIZE);
		if (len < 0)
			return len;

		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.gate_way,
				strlen((char *)in->body.kvp_ip_val.gate_way),
				UTF16_HOST_ENDIAN,
				(wchar_t *)out->kvp_ip_val.gate_way,
				MAX_GATEWAY_SIZE);
		if (len < 0)
			return len;

		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.dns_addr,
				strlen((char *)in->body.kvp_ip_val.dns_addr),
				UTF16_HOST_ENDIAN,
				(wchar_t *)out->kvp_ip_val.dns_addr,
				MAX_IP_ADDR_SIZE);
		if (len < 0)
			return len;

		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.adapter_id,
				strlen((char *)in->body.kvp_ip_val.adapter_id),
				UTF16_HOST_ENDIAN,
				(wchar_t *)out->kvp_ip_val.adapter_id,
				MAX_ADAPTER_ID_SIZE);
		if (len < 0)
			return len;

		out->kvp_ip_val.dhcp_enabled =
			in->body.kvp_ip_val.dhcp_enabled;
		out->kvp_ip_val.addr_family =
			in->body.kvp_ip_val.addr_family;
	}

	return 0;
}

static void process_ib_ipinfo(void *in_msg, void *out_msg, int op)
{
	struct hv_kvp_ip_msg *in = in_msg;
	struct hv_kvp_msg *out = out_msg;

	switch (op) {
	case KVP_OP_SET_IP_INFO:
		/*
		 * Transform all parameters into utf8 encoding.
		 */
		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.ip_addr,
				MAX_IP_ADDR_SIZE,
				UTF16_LITTLE_ENDIAN,
				(__u8 *)out->body.kvp_ip_val.ip_addr,
				MAX_IP_ADDR_SIZE);

		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.sub_net,
				MAX_IP_ADDR_SIZE,
				UTF16_LITTLE_ENDIAN,
				(__u8 *)out->body.kvp_ip_val.sub_net,
				MAX_IP_ADDR_SIZE);

		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.gate_way,
				MAX_GATEWAY_SIZE,
				UTF16_LITTLE_ENDIAN,
				(__u8 *)out->body.kvp_ip_val.gate_way,
				MAX_GATEWAY_SIZE);

		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.dns_addr,
				MAX_IP_ADDR_SIZE,
				UTF16_LITTLE_ENDIAN,
				(__u8 *)out->body.kvp_ip_val.dns_addr,
				MAX_IP_ADDR_SIZE);

		out->body.kvp_ip_val.dhcp_enabled = in->kvp_ip_val.dhcp_enabled;

		/* fallthrough */

	case KVP_OP_GET_IP_INFO:
		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.adapter_id,
				MAX_ADAPTER_ID_SIZE,
				UTF16_LITTLE_ENDIAN,
				(__u8 *)out->body.kvp_ip_val.adapter_id,
				MAX_ADAPTER_ID_SIZE);

		out->body.kvp_ip_val.addr_family = in->kvp_ip_val.addr_family;
	}
}




static void
kvp_send_key(struct work_struct *dummy)
{
	struct hv_kvp_msg *message;
	struct hv_kvp_msg *in_msg;
	__u8 operation = kvp_transaction.kvp_msg->kvp_hdr.operation;
	__u8 pool = kvp_transaction.kvp_msg->kvp_hdr.pool;
	__u32 val32;
	__u64 val64;
	int rc;

	/* The transaction state is wrong. */
	if (kvp_transaction.state != HVUTIL_HOSTMSG_RECEIVED)
		return;

	message = kzalloc(sizeof(*message), GFP_KERNEL);
	if (!message)
		return;

	message->kvp_hdr.operation = operation;
	message->kvp_hdr.pool = pool;
	in_msg = kvp_transaction.kvp_msg;

	/*
	 * The key/value strings sent from the host are encoded in
	 * in utf16; convert it to utf8 strings.
	 * The host assures us that the utf16 strings will not exceed
	 * the max lengths specified. We will however, reserve room
	 * for the string terminating character - in the utf16s_utf8s()
	 * function we limit the size of the buffer where the converted
	 * string is placed to HV_KVP_EXCHANGE_MAX_*_SIZE -1 to guarantee
	 * that the strings can be properly terminated!
	 */

	switch (message->kvp_hdr.operation) {
	case KVP_OP_SET_IP_INFO:
		process_ib_ipinfo(in_msg, message, KVP_OP_SET_IP_INFO);
		break;
	case KVP_OP_GET_IP_INFO:
		/*
		 * We only need to pass on the info of operation, adapter_id
		 * and addr_family to the userland kvp daemon.
		 */
		process_ib_ipinfo(in_msg, message, KVP_OP_GET_IP_INFO);
		break;
	case KVP_OP_SET:
		switch (in_msg->body.kvp_set.data.value_type) {
		case REG_SZ:
			/*
			 * The value is a string - utf16 encoding.
			 */
			message->body.kvp_set.data.value_size =
				utf16s_to_utf8s(
				(wchar_t *)in_msg->body.kvp_set.data.value,
				in_msg->body.kvp_set.data.value_size,
				UTF16_LITTLE_ENDIAN,
				message->body.kvp_set.data.value,
				HV_KVP_EXCHANGE_MAX_VALUE_SIZE - 1) + 1;
			break;

		case REG_U32:
			/*
			 * The value is a 32 bit scalar.
			 * We save this as a utf8 string.
			 */
			val32 = in_msg->body.kvp_set.data.value_u32;
			message->body.kvp_set.data.value_size =
				sprintf(message->body.kvp_set.data.value,
					"%u", val32) + 1;
			break;

		case REG_U64:
			/*
			 * The value is a 64 bit scalar.
			 * We save this as a utf8 string.
			 */
			val64 = in_msg->body.kvp_set.data.value_u64;
			message->body.kvp_set.data.value_size =
				sprintf(message->body.kvp_set.data.value,
					"%llu", val64) + 1;
			break;

		}

		/*
		 * The key is always a string - utf16 encoding.
		 */
		message->body.kvp_set.data.key_size =
			utf16s_to_utf8s(
			(wchar_t *)in_msg->body.kvp_set.data.key,
			in_msg->body.kvp_set.data.key_size,
			UTF16_LITTLE_ENDIAN,
			message->body.kvp_set.data.key,
			HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;

		break;

	case KVP_OP_GET:
		message->body.kvp_get.data.key_size =
			utf16s_to_utf8s(
			(wchar_t *)in_msg->body.kvp_get.data.key,
			in_msg->body.kvp_get.data.key_size,
			UTF16_LITTLE_ENDIAN,
			message->body.kvp_get.data.key,
			HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
		break;

	case KVP_OP_DELETE:
		message->body.kvp_delete.key_size =
			utf16s_to_utf8s(
			(wchar_t *)in_msg->body.kvp_delete.key,
			in_msg->body.kvp_delete.key_size,
			UTF16_LITTLE_ENDIAN,
			message->body.kvp_delete.key,
			HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
		break;

	case KVP_OP_ENUMERATE:
		message->body.kvp_enum_data.index =
			in_msg->body.kvp_enum_data.index;
		break;
	}

	kvp_transaction.state = HVUTIL_USERSPACE_REQ;
	rc = hvutil_transport_send(hvt, message, sizeof(*message), NULL);
	if (rc) {
		pr_debug("KVP: failed to communicate to the daemon: %d\n", rc);
		if (cancel_delayed_work_sync(&kvp_timeout_work)) {
			kvp_respond_to_host(message, HV_E_FAIL);
			kvp_transaction.state = HVUTIL_READY;
		}
	}

	kfree(message);
}

/*
 * Send a response back to the host.
 */

static void
kvp_respond_to_host(struct hv_kvp_msg *msg_to_host, int error)
{
	struct hv_kvp_msg  *kvp_msg;
	struct hv_kvp_exchg_msg_value  *kvp_data;
	char	*key_name;
	char	*value;
	struct icmsg_hdr *icmsghdrp;
	int	keylen = 0;
	int	valuelen = 0;
	u32	buf_len;
	struct vmbus_channel *channel;
	u64	req_id;
	int ret;

	/*
	 * Copy the global state for completing the transaction. Note that
	 * only one transaction can be active at a time.
	 */

	buf_len = kvp_transaction.recv_len;
	channel = kvp_transaction.recv_channel;
	req_id = kvp_transaction.recv_req_id;

	icmsghdrp = (struct icmsg_hdr *)
			&recv_buffer[sizeof(struct vmbuspipe_hdr)];

	if (channel->onchannel_callback == NULL)
		/*
		 * We have raced with util driver being unloaded;
		 * silently return.
		 */
		return;

	icmsghdrp->status = error;

	/*
	 * If the error parameter is set, terminate the host's enumeration
	 * on this pool.
	 */
	if (error) {
		/*
		 * Something failed or we have timed out;
		 * terminate the current host-side iteration.
		 */
		goto response_done;
	}

	kvp_msg = (struct hv_kvp_msg *)
			&recv_buffer[sizeof(struct vmbuspipe_hdr) +
			sizeof(struct icmsg_hdr)];

	switch (kvp_transaction.kvp_msg->kvp_hdr.operation) {
	case KVP_OP_GET_IP_INFO:
		ret = process_ob_ipinfo(msg_to_host,
				 (struct hv_kvp_ip_msg *)kvp_msg,
				 KVP_OP_GET_IP_INFO);
		if (ret < 0)
			icmsghdrp->status = HV_E_FAIL;

		goto response_done;
	case KVP_OP_SET_IP_INFO:
		goto response_done;
	case KVP_OP_GET:
		kvp_data = &kvp_msg->body.kvp_get.data;
		goto copy_value;

	case KVP_OP_SET:
	case KVP_OP_DELETE:
		goto response_done;

	default:
		break;
	}

	kvp_data = &kvp_msg->body.kvp_enum_data.data;
	key_name = msg_to_host->body.kvp_enum_data.data.key;

	/*
	 * The windows host expects the key/value pair to be encoded
	 * in utf16. Ensure that the key/value size reported to the host
	 * will be less than or equal to the MAX size (including the
	 * terminating character).
	 */
	keylen = utf8s_to_utf16s(key_name, strlen(key_name), UTF16_HOST_ENDIAN,
				(wchar_t *) kvp_data->key,
				(HV_KVP_EXCHANGE_MAX_KEY_SIZE / 2) - 2);
	kvp_data->key_size = 2*(keylen + 1); /* utf16 encoding */

copy_value:
	value = msg_to_host->body.kvp_enum_data.data.value;
	valuelen = utf8s_to_utf16s(value, strlen(value), UTF16_HOST_ENDIAN,
				(wchar_t *) kvp_data->value,
				(HV_KVP_EXCHANGE_MAX_VALUE_SIZE / 2) - 2);
	kvp_data->value_size = 2*(valuelen + 1); /* utf16 encoding */

	/*
	 * If the utf8s to utf16s conversion failed; notify host
	 * of the error.
	 */
	if ((keylen < 0) || (valuelen < 0))
		icmsghdrp->status = HV_E_FAIL;

	kvp_data->value_type = REG_SZ; /* all our values are strings */

response_done:
	icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;

	vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
				VM_PKT_DATA_INBAND, 0);
}

/*
 * This callback is invoked when we get a KVP message from the host.
 * The host ensures that only one KVP transaction can be active at a time.
 * KVP implementation in Linux needs to forward the key to a user-mde
 * component to retrieve the corresponding value. Consequently, we cannot
 * respond to the host in the context of this callback. Since the host
 * guarantees that at most only one transaction can be active at a time,
 * we stash away the transaction state in a set of global variables.
 */

void hv_kvp_onchannelcallback(void *context)
{
	struct vmbus_channel *channel = context;
	u32 recvlen;
	u64 requestid;

	struct hv_kvp_msg *kvp_msg;

	struct icmsg_hdr *icmsghdrp;
	int kvp_srv_version;
	static enum {NEGO_NOT_STARTED,
		     NEGO_IN_PROGRESS,
		     NEGO_FINISHED} host_negotiatied = NEGO_NOT_STARTED;

	if (kvp_transaction.state < HVUTIL_READY) {
		/*
		 * If userspace daemon is not connected and host is asking
		 * us to negotiate we need to delay to not lose messages.
		 * This is important for Failover IP setting.
		 */
		if (host_negotiatied == NEGO_NOT_STARTED) {
			host_negotiatied = NEGO_IN_PROGRESS;
			schedule_delayed_work(&kvp_host_handshake_work,
				      HV_UTIL_NEGO_TIMEOUT * HZ);
		}
		return;
	}
	if (kvp_transaction.state > HVUTIL_READY)
		return;

	vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 4, &recvlen,
			 &requestid);

	if (recvlen > 0) {
		icmsghdrp = (struct icmsg_hdr *)&recv_buffer[
			sizeof(struct vmbuspipe_hdr)];

		if (icmsghdrp->icmsgtype == ICMSGTYPE_NEGOTIATE) {
			if (vmbus_prep_negotiate_resp(icmsghdrp,
				 recv_buffer, fw_versions, FW_VER_COUNT,
				 kvp_versions, KVP_VER_COUNT,
				 NULL, &kvp_srv_version)) {
				pr_info("KVP IC version %d.%d\n",
					kvp_srv_version >> 16,
					kvp_srv_version & 0xFFFF);
			}
		} else {
			kvp_msg = (struct hv_kvp_msg *)&recv_buffer[
				sizeof(struct vmbuspipe_hdr) +
				sizeof(struct icmsg_hdr)];

			/*
			 * Stash away this global state for completing the
			 * transaction; note transactions are serialized.
			 */

			kvp_transaction.recv_len = recvlen;
			kvp_transaction.recv_req_id = requestid;
			kvp_transaction.kvp_msg = kvp_msg;

			if (kvp_transaction.state < HVUTIL_READY) {
				/* Userspace is not registered yet */
				kvp_respond_to_host(NULL, HV_E_FAIL);
				return;
			}
			kvp_transaction.state = HVUTIL_HOSTMSG_RECEIVED;

			/*
			 * Get the information from the
			 * user-mode component.
			 * component. This transaction will be
			 * completed when we get the value from
			 * the user-mode component.
			 * Set a timeout to deal with
			 * user-mode not responding.
			 */
			schedule_work(&kvp_sendkey_work);
			schedule_delayed_work(&kvp_timeout_work,
					      HV_UTIL_TIMEOUT * HZ);

			return;

		}

		icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
			| ICMSGHDRFLAG_RESPONSE;

		vmbus_sendpacket(channel, recv_buffer,
				       recvlen, requestid,
				       VM_PKT_DATA_INBAND, 0);

		host_negotiatied = NEGO_FINISHED;
		hv_poll_channel(kvp_transaction.recv_channel, kvp_poll_wrapper);
	}

}

static void kvp_on_reset(void)
{
	if (cancel_delayed_work_sync(&kvp_timeout_work))
		kvp_respond_to_host(NULL, HV_E_FAIL);
	kvp_transaction.state = HVUTIL_DEVICE_INIT;
}

int
hv_kvp_init(struct hv_util_service *srv)
{
	recv_buffer = srv->recv_buffer;
	kvp_transaction.recv_channel = srv->channel;

	/*
	 * When this driver loads, the user level daemon that
	 * processes the host requests may not yet be running.
	 * Defer processing channel callbacks until the daemon
	 * has registered.
	 */
	kvp_transaction.state = HVUTIL_DEVICE_INIT;

	hvt = hvutil_transport_init(kvp_devname, CN_KVP_IDX, CN_KVP_VAL,
				    kvp_on_msg, kvp_on_reset);
	if (!hvt)
		return -EFAULT;

	return 0;
}

void hv_kvp_deinit(void)
{
	kvp_transaction.state = HVUTIL_DEVICE_DYING;
	cancel_delayed_work_sync(&kvp_host_handshake_work);
	cancel_delayed_work_sync(&kvp_timeout_work);
	cancel_work_sync(&kvp_sendkey_work);
	hvutil_transport_destroy(hvt);
}