xref: /linux/drivers/hv/hv_kvp.c (revision c0e297dc61f8d4453e07afbea1fa8d0e67cd4a34)
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 /*
50  * Global state maintained for transaction that is being processed. For a class
51  * of integration services, including the "KVP service", the specified protocol
52  * is a "request/response" protocol which means that there can only be single
53  * outstanding transaction from the host at any given point in time. We use
54  * this to simplify memory management in this driver - we cache and process
55  * only one message at a time.
56  *
57  * While the request/response protocol is guaranteed by the host, we further
58  * ensure this by serializing packet processing in this driver - we do not
59  * read additional packets from the VMBUs until the current packet is fully
60  * handled.
61  */
62 
63 static struct {
64 	int state;   /* hvutil_device_state */
65 	int recv_len; /* number of bytes received. */
66 	struct hv_kvp_msg  *kvp_msg; /* current message */
67 	struct vmbus_channel *recv_channel; /* chn we got the request */
68 	u64 recv_req_id; /* request ID. */
69 	void *kvp_context; /* for the channel callback */
70 } kvp_transaction;
71 
72 /*
73  * This state maintains the version number registered by the daemon.
74  */
75 static int dm_reg_value;
76 
77 static void kvp_send_key(struct work_struct *dummy);
78 
79 
80 static void kvp_respond_to_host(struct hv_kvp_msg *msg, int error);
81 static void kvp_timeout_func(struct work_struct *dummy);
82 static void kvp_register(int);
83 
84 static DECLARE_DELAYED_WORK(kvp_timeout_work, kvp_timeout_func);
85 static DECLARE_WORK(kvp_sendkey_work, kvp_send_key);
86 
87 static const char kvp_devname[] = "vmbus/hv_kvp";
88 static u8 *recv_buffer;
89 static struct hvutil_transport *hvt;
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 
97 static void
98 kvp_register(int reg_value)
99 {
100 
101 	struct hv_kvp_msg *kvp_msg;
102 	char *version;
103 
104 	kvp_msg = kzalloc(sizeof(*kvp_msg), GFP_KERNEL);
105 
106 	if (kvp_msg) {
107 		version = kvp_msg->body.kvp_register.version;
108 		kvp_msg->kvp_hdr.operation = reg_value;
109 		strcpy(version, HV_DRV_VERSION);
110 
111 		hvutil_transport_send(hvt, kvp_msg, sizeof(*kvp_msg));
112 		kfree(kvp_msg);
113 	}
114 }
115 
116 static void kvp_timeout_func(struct work_struct *dummy)
117 {
118 	/*
119 	 * If the timer fires, the user-mode component has not responded;
120 	 * process the pending transaction.
121 	 */
122 	kvp_respond_to_host(NULL, HV_E_FAIL);
123 
124 	/* Transaction is finished, reset the state. */
125 	if (kvp_transaction.state > HVUTIL_READY)
126 		kvp_transaction.state = HVUTIL_READY;
127 
128 	hv_poll_channel(kvp_transaction.kvp_context,
129 			hv_kvp_onchannelcallback);
130 }
131 
132 static int kvp_handle_handshake(struct hv_kvp_msg *msg)
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 		return -EINVAL;
148 	}
149 
150 	/*
151 	 * We have a compatible daemon; complete the handshake.
152 	 */
153 	pr_debug("KVP: userspace daemon ver. %d registered\n",
154 		 KVP_OP_REGISTER);
155 	kvp_register(dm_reg_value);
156 	kvp_transaction.state = HVUTIL_READY;
157 
158 	return 0;
159 }
160 
161 
162 /*
163  * Callback when data is received from user mode.
164  */
165 
166 static int kvp_on_msg(void *msg, int len)
167 {
168 	struct hv_kvp_msg *message = (struct hv_kvp_msg *)msg;
169 	struct hv_kvp_msg_enumerate *data;
170 	int	error = 0;
171 
172 	if (len < sizeof(*message))
173 		return -EINVAL;
174 
175 	/*
176 	 * If we are negotiating the version information
177 	 * with the daemon; handle that first.
178 	 */
179 
180 	if (kvp_transaction.state < HVUTIL_READY) {
181 		return kvp_handle_handshake(message);
182 	}
183 
184 	/* We didn't send anything to userspace so the reply is spurious */
185 	if (kvp_transaction.state < HVUTIL_USERSPACE_REQ)
186 		return -EINVAL;
187 
188 	kvp_transaction.state = HVUTIL_USERSPACE_RECV;
189 
190 	/*
191 	 * Based on the version of the daemon, we propagate errors from the
192 	 * daemon differently.
193 	 */
194 
195 	data = &message->body.kvp_enum_data;
196 
197 	switch (dm_reg_value) {
198 	case KVP_OP_REGISTER:
199 		/*
200 		 * Null string is used to pass back error condition.
201 		 */
202 		if (data->data.key[0] == 0)
203 			error = HV_S_CONT;
204 		break;
205 
206 	case KVP_OP_REGISTER1:
207 		/*
208 		 * We use the message header information from
209 		 * the user level daemon to transmit errors.
210 		 */
211 		error = message->error;
212 		break;
213 	}
214 
215 	/*
216 	 * Complete the transaction by forwarding the key value
217 	 * to the host. But first, cancel the timeout.
218 	 */
219 	if (cancel_delayed_work_sync(&kvp_timeout_work)) {
220 		kvp_respond_to_host(message, error);
221 		kvp_transaction.state = HVUTIL_READY;
222 		hv_poll_channel(kvp_transaction.kvp_context,
223 				hv_kvp_onchannelcallback);
224 	}
225 
226 	return 0;
227 }
228 
229 
230 static int process_ob_ipinfo(void *in_msg, void *out_msg, int op)
231 {
232 	struct hv_kvp_msg *in = in_msg;
233 	struct hv_kvp_ip_msg *out = out_msg;
234 	int len;
235 
236 	switch (op) {
237 	case KVP_OP_GET_IP_INFO:
238 		/*
239 		 * Transform all parameters into utf16 encoding.
240 		 */
241 		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.ip_addr,
242 				strlen((char *)in->body.kvp_ip_val.ip_addr),
243 				UTF16_HOST_ENDIAN,
244 				(wchar_t *)out->kvp_ip_val.ip_addr,
245 				MAX_IP_ADDR_SIZE);
246 		if (len < 0)
247 			return len;
248 
249 		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.sub_net,
250 				strlen((char *)in->body.kvp_ip_val.sub_net),
251 				UTF16_HOST_ENDIAN,
252 				(wchar_t *)out->kvp_ip_val.sub_net,
253 				MAX_IP_ADDR_SIZE);
254 		if (len < 0)
255 			return len;
256 
257 		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.gate_way,
258 				strlen((char *)in->body.kvp_ip_val.gate_way),
259 				UTF16_HOST_ENDIAN,
260 				(wchar_t *)out->kvp_ip_val.gate_way,
261 				MAX_GATEWAY_SIZE);
262 		if (len < 0)
263 			return len;
264 
265 		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.dns_addr,
266 				strlen((char *)in->body.kvp_ip_val.dns_addr),
267 				UTF16_HOST_ENDIAN,
268 				(wchar_t *)out->kvp_ip_val.dns_addr,
269 				MAX_IP_ADDR_SIZE);
270 		if (len < 0)
271 			return len;
272 
273 		len = utf8s_to_utf16s((char *)in->body.kvp_ip_val.adapter_id,
274 				strlen((char *)in->body.kvp_ip_val.adapter_id),
275 				UTF16_HOST_ENDIAN,
276 				(wchar_t *)out->kvp_ip_val.adapter_id,
277 				MAX_IP_ADDR_SIZE);
278 		if (len < 0)
279 			return len;
280 
281 		out->kvp_ip_val.dhcp_enabled =
282 			in->body.kvp_ip_val.dhcp_enabled;
283 		out->kvp_ip_val.addr_family =
284 			in->body.kvp_ip_val.addr_family;
285 	}
286 
287 	return 0;
288 }
289 
290 static void process_ib_ipinfo(void *in_msg, void *out_msg, int op)
291 {
292 	struct hv_kvp_ip_msg *in = in_msg;
293 	struct hv_kvp_msg *out = out_msg;
294 
295 	switch (op) {
296 	case KVP_OP_SET_IP_INFO:
297 		/*
298 		 * Transform all parameters into utf8 encoding.
299 		 */
300 		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.ip_addr,
301 				MAX_IP_ADDR_SIZE,
302 				UTF16_LITTLE_ENDIAN,
303 				(__u8 *)out->body.kvp_ip_val.ip_addr,
304 				MAX_IP_ADDR_SIZE);
305 
306 		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.sub_net,
307 				MAX_IP_ADDR_SIZE,
308 				UTF16_LITTLE_ENDIAN,
309 				(__u8 *)out->body.kvp_ip_val.sub_net,
310 				MAX_IP_ADDR_SIZE);
311 
312 		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.gate_way,
313 				MAX_GATEWAY_SIZE,
314 				UTF16_LITTLE_ENDIAN,
315 				(__u8 *)out->body.kvp_ip_val.gate_way,
316 				MAX_GATEWAY_SIZE);
317 
318 		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.dns_addr,
319 				MAX_IP_ADDR_SIZE,
320 				UTF16_LITTLE_ENDIAN,
321 				(__u8 *)out->body.kvp_ip_val.dns_addr,
322 				MAX_IP_ADDR_SIZE);
323 
324 		out->body.kvp_ip_val.dhcp_enabled = in->kvp_ip_val.dhcp_enabled;
325 
326 	default:
327 		utf16s_to_utf8s((wchar_t *)in->kvp_ip_val.adapter_id,
328 				MAX_ADAPTER_ID_SIZE,
329 				UTF16_LITTLE_ENDIAN,
330 				(__u8 *)out->body.kvp_ip_val.adapter_id,
331 				MAX_ADAPTER_ID_SIZE);
332 
333 		out->body.kvp_ip_val.addr_family = in->kvp_ip_val.addr_family;
334 	}
335 }
336 
337 
338 
339 
340 static void
341 kvp_send_key(struct work_struct *dummy)
342 {
343 	struct hv_kvp_msg *message;
344 	struct hv_kvp_msg *in_msg;
345 	__u8 operation = kvp_transaction.kvp_msg->kvp_hdr.operation;
346 	__u8 pool = kvp_transaction.kvp_msg->kvp_hdr.pool;
347 	__u32 val32;
348 	__u64 val64;
349 	int rc;
350 
351 	/* The transaction state is wrong. */
352 	if (kvp_transaction.state != HVUTIL_HOSTMSG_RECEIVED)
353 		return;
354 
355 	message = kzalloc(sizeof(*message), GFP_KERNEL);
356 	message->kvp_hdr.operation = operation;
357 	message->kvp_hdr.pool = pool;
358 	in_msg = kvp_transaction.kvp_msg;
359 
360 	/*
361 	 * The key/value strings sent from the host are encoded in
362 	 * in utf16; convert it to utf8 strings.
363 	 * The host assures us that the utf16 strings will not exceed
364 	 * the max lengths specified. We will however, reserve room
365 	 * for the string terminating character - in the utf16s_utf8s()
366 	 * function we limit the size of the buffer where the converted
367 	 * string is placed to HV_KVP_EXCHANGE_MAX_*_SIZE -1 to gaurantee
368 	 * that the strings can be properly terminated!
369 	 */
370 
371 	switch (message->kvp_hdr.operation) {
372 	case KVP_OP_SET_IP_INFO:
373 		process_ib_ipinfo(in_msg, message, KVP_OP_SET_IP_INFO);
374 		break;
375 	case KVP_OP_GET_IP_INFO:
376 		process_ib_ipinfo(in_msg, message, KVP_OP_GET_IP_INFO);
377 		break;
378 	case KVP_OP_SET:
379 		switch (in_msg->body.kvp_set.data.value_type) {
380 		case REG_SZ:
381 			/*
382 			 * The value is a string - utf16 encoding.
383 			 */
384 			message->body.kvp_set.data.value_size =
385 				utf16s_to_utf8s(
386 				(wchar_t *)in_msg->body.kvp_set.data.value,
387 				in_msg->body.kvp_set.data.value_size,
388 				UTF16_LITTLE_ENDIAN,
389 				message->body.kvp_set.data.value,
390 				HV_KVP_EXCHANGE_MAX_VALUE_SIZE - 1) + 1;
391 				break;
392 
393 		case REG_U32:
394 			/*
395 			 * The value is a 32 bit scalar.
396 			 * We save this as a utf8 string.
397 			 */
398 			val32 = in_msg->body.kvp_set.data.value_u32;
399 			message->body.kvp_set.data.value_size =
400 				sprintf(message->body.kvp_set.data.value,
401 					"%d", val32) + 1;
402 			break;
403 
404 		case REG_U64:
405 			/*
406 			 * The value is a 64 bit scalar.
407 			 * We save this as a utf8 string.
408 			 */
409 			val64 = in_msg->body.kvp_set.data.value_u64;
410 			message->body.kvp_set.data.value_size =
411 				sprintf(message->body.kvp_set.data.value,
412 					"%llu", val64) + 1;
413 			break;
414 
415 		}
416 	case KVP_OP_GET:
417 		message->body.kvp_set.data.key_size =
418 			utf16s_to_utf8s(
419 			(wchar_t *)in_msg->body.kvp_set.data.key,
420 			in_msg->body.kvp_set.data.key_size,
421 			UTF16_LITTLE_ENDIAN,
422 			message->body.kvp_set.data.key,
423 			HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
424 			break;
425 
426 	case KVP_OP_DELETE:
427 		message->body.kvp_delete.key_size =
428 			utf16s_to_utf8s(
429 			(wchar_t *)in_msg->body.kvp_delete.key,
430 			in_msg->body.kvp_delete.key_size,
431 			UTF16_LITTLE_ENDIAN,
432 			message->body.kvp_delete.key,
433 			HV_KVP_EXCHANGE_MAX_KEY_SIZE - 1) + 1;
434 			break;
435 
436 	case KVP_OP_ENUMERATE:
437 		message->body.kvp_enum_data.index =
438 			in_msg->body.kvp_enum_data.index;
439 			break;
440 	}
441 
442 	kvp_transaction.state = HVUTIL_USERSPACE_REQ;
443 	rc = hvutil_transport_send(hvt, message, sizeof(*message));
444 	if (rc) {
445 		pr_debug("KVP: failed to communicate to the daemon: %d\n", rc);
446 		if (cancel_delayed_work_sync(&kvp_timeout_work)) {
447 			kvp_respond_to_host(message, HV_E_FAIL);
448 			kvp_transaction.state = HVUTIL_READY;
449 		}
450 	}
451 
452 	kfree(message);
453 
454 	return;
455 }
456 
457 /*
458  * Send a response back to the host.
459  */
460 
461 static void
462 kvp_respond_to_host(struct hv_kvp_msg *msg_to_host, int error)
463 {
464 	struct hv_kvp_msg  *kvp_msg;
465 	struct hv_kvp_exchg_msg_value  *kvp_data;
466 	char	*key_name;
467 	char	*value;
468 	struct icmsg_hdr *icmsghdrp;
469 	int	keylen = 0;
470 	int	valuelen = 0;
471 	u32	buf_len;
472 	struct vmbus_channel *channel;
473 	u64	req_id;
474 	int ret;
475 
476 	/*
477 	 * Copy the global state for completing the transaction. Note that
478 	 * only one transaction can be active at a time.
479 	 */
480 
481 	buf_len = kvp_transaction.recv_len;
482 	channel = kvp_transaction.recv_channel;
483 	req_id = kvp_transaction.recv_req_id;
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 
550 copy_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 
566 response_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  * This callback is invoked when we get a KVP message from the host.
575  * The host ensures that only one KVP transaction can be active at a time.
576  * KVP implementation in Linux needs to forward the key to a user-mde
577  * component to retrive the corresponding value. Consequently, we cannot
578  * respond to the host in the conext of this callback. Since the host
579  * guarantees that at most only one transaction can be active at a time,
580  * we stash away the transaction state in a set of global variables.
581  */
582 
583 void hv_kvp_onchannelcallback(void *context)
584 {
585 	struct vmbus_channel *channel = context;
586 	u32 recvlen;
587 	u64 requestid;
588 
589 	struct hv_kvp_msg *kvp_msg;
590 
591 	struct icmsg_hdr *icmsghdrp;
592 	struct icmsg_negotiate *negop = NULL;
593 	int util_fw_version;
594 	int kvp_srv_version;
595 
596 	if (kvp_transaction.state > HVUTIL_READY) {
597 		/*
598 		 * We will defer processing this callback once
599 		 * the current transaction is complete.
600 		 */
601 		kvp_transaction.kvp_context = context;
602 		return;
603 	}
604 	kvp_transaction.kvp_context = NULL;
605 
606 	vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 4, &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.kvp_msg = kvp_msg;
650 
651 			if (kvp_transaction.state < HVUTIL_READY) {
652 				/* Userspace is not registered yet */
653 				kvp_respond_to_host(NULL, HV_E_FAIL);
654 				return;
655 			}
656 			kvp_transaction.state = HVUTIL_HOSTMSG_RECEIVED;
657 
658 			/*
659 			 * Get the information from the
660 			 * user-mode component.
661 			 * component. This transaction will be
662 			 * completed when we get the value from
663 			 * the user-mode component.
664 			 * Set a timeout to deal with
665 			 * user-mode not responding.
666 			 */
667 			schedule_work(&kvp_sendkey_work);
668 			schedule_delayed_work(&kvp_timeout_work, 5*HZ);
669 
670 			return;
671 
672 		}
673 
674 		icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
675 			| ICMSGHDRFLAG_RESPONSE;
676 
677 		vmbus_sendpacket(channel, recv_buffer,
678 				       recvlen, requestid,
679 				       VM_PKT_DATA_INBAND, 0);
680 	}
681 
682 }
683 
684 static void kvp_on_reset(void)
685 {
686 	if (cancel_delayed_work_sync(&kvp_timeout_work))
687 		kvp_respond_to_host(NULL, HV_E_FAIL);
688 	kvp_transaction.state = HVUTIL_DEVICE_INIT;
689 }
690 
691 int
692 hv_kvp_init(struct hv_util_service *srv)
693 {
694 	recv_buffer = srv->recv_buffer;
695 
696 	/*
697 	 * When this driver loads, the user level daemon that
698 	 * processes the host requests may not yet be running.
699 	 * Defer processing channel callbacks until the daemon
700 	 * has registered.
701 	 */
702 	kvp_transaction.state = HVUTIL_DEVICE_INIT;
703 
704 	hvt = hvutil_transport_init(kvp_devname, CN_KVP_IDX, CN_KVP_VAL,
705 				    kvp_on_msg, kvp_on_reset);
706 	if (!hvt)
707 		return -EFAULT;
708 
709 	return 0;
710 }
711 
712 void hv_kvp_deinit(void)
713 {
714 	kvp_transaction.state = HVUTIL_DEVICE_DYING;
715 	cancel_delayed_work_sync(&kvp_timeout_work);
716 	cancel_work_sync(&kvp_sendkey_work);
717 	hvutil_transport_destroy(hvt);
718 }
719