Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 767 insertions, 0 deletions

diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c
new file mode 100644
index 000000000..d6106e1a0
--- /dev/null
+++ b/drivers/hv/hv_kvp.c
@@ -0,0 +1,767 @@
+/*
+ * 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,
+					"%d", 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);
+}