Drivers: hv: Support the newly introduced KVP messages in the driver

Support the newly defined KVP message types. It turns out that the host
pushes a set of standard key value pairs as soon as the guest opens the KVP channel.
Since we cannot handle these tuples until the user level daemon loads up, defer
reading the KVP channel until the user level daemon is launched.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hv/hv_kvp.c

@@ -42,9 +42,10 @@
 static struct {
 	bool active; /* transaction status - active or not */
 	int recv_len; /* number of bytes received. */
-	int index; /* current index */
+	struct hv_kvp_msg  *kvp_msg; /* current message */
 	struct vmbus_channel *recv_channel; /* chn we got the request */
 	u64 recv_req_id; /* request ID. */
+	void *kvp_context; /* for the channel callback */
 } kvp_transaction;
 
 static void kvp_send_key(struct work_struct *dummy);
@@ -110,12 +111,15 @@ kvp_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
 	struct hv_kvp_msg_enumerate *data;
 
 	message = (struct hv_kvp_msg *)msg->data;
-	if (message->kvp_hdr.operation == KVP_OP_REGISTER) {
+	switch (message->kvp_hdr.operation) {
+	case KVP_OP_REGISTER:
 		pr_info("KVP: user-mode registering done.\n");
 		kvp_register();
-	}
+		kvp_transaction.active = false;
+		hv_kvp_onchannelcallback(kvp_transaction.kvp_context);
+		break;
 
-	if (message->kvp_hdr.operation == KVP_OP_ENUMERATE) {
+	default:
 		data = &message->body.kvp_enum_data;
 		/*
 		 * Complete the transaction by forwarding the key value
@@ -133,21 +137,104 @@ kvp_send_key(struct work_struct *dummy)
 {
 	struct cn_msg *msg;
 	struct hv_kvp_msg *message;
-	int index = kvp_transaction.index;
+	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;
 
 	msg = kzalloc(sizeof(*msg) + sizeof(struct hv_kvp_msg) , GFP_ATOMIC);
+	if (!msg)
+		return;
 
-	if (msg) {
 	msg->id.idx =  CN_KVP_IDX;
 	msg->id.val = CN_KVP_VAL;
 
 	message = (struct hv_kvp_msg *)msg->data;
-		message->kvp_hdr.operation = KVP_OP_ENUMERATE;
-		message->body.kvp_enum_data.index = index;
+	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 gaurantee
+	 * that the strings can be properly terminated!
+	 */
+
+	switch (message->kvp_hdr.operation) {
+	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;
+
+		}
+	case KVP_OP_GET:
+		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_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;
+	}
+
 	msg->len = sizeof(struct hv_kvp_msg);
 	cn_netlink_send(msg, 0, GFP_ATOMIC);
 	kfree(msg);
-	}
+
 	return;
 }
 
@@ -159,10 +246,11 @@ static void
 kvp_respond_to_host(char *key, char *value, int error)
 {
 	struct hv_kvp_msg  *kvp_msg;
-	struct hv_kvp_msg_enumerate  *kvp_data;
+	struct hv_kvp_exchg_msg_value  *kvp_data;
 	char	*key_name;
 	struct icmsg_hdr *icmsghdrp;
-	int	keylen, valuelen;
+	int	keylen = 0;
+	int	valuelen = 0;
 	u32	buf_len;
 	struct vmbus_channel *channel;
 	u64	req_id;
@@ -189,6 +277,9 @@ kvp_respond_to_host(char *key, char *value, int error)
 
 	kvp_transaction.active = false;
 
+	icmsghdrp = (struct icmsg_hdr *)
+			&recv_buffer[sizeof(struct vmbuspipe_hdr)];
+
 	if (channel->onchannel_callback == NULL)
 		/*
 		 * We have raced with util driver being unloaded;
@@ -196,41 +287,66 @@ kvp_respond_to_host(char *key, char *value, int error)
 		 */
 		return;
 
-	icmsghdrp = (struct icmsg_hdr *)
-			&recv_buffer[sizeof(struct vmbuspipe_hdr)];
-	kvp_msg = (struct hv_kvp_msg *)
-			&recv_buffer[sizeof(struct vmbuspipe_hdr) +
-			sizeof(struct icmsg_hdr)];
-	kvp_data = &kvp_msg->body.kvp_enum_data;
-	key_name = key;
 
 	/*
 	 * If the error parameter is set, terminate the host's enumeration.
 	 */
 	if (error) {
 		/*
-		 * We don't support this index or the we have timedout;
+		 * Something failed or the we have timedout;
 		 * terminate the host-side iteration by returning an error.
 		 */
 		icmsghdrp->status = HV_E_FAIL;
 		goto response_done;
 	}
 
+	icmsghdrp->status = HV_S_OK;
+
+	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:
+		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 = key;
+
 	/*
 	 * The windows host expects the key/value pair to be encoded
-	 * in utf16.
+	 * 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->data.key,
-				HV_KVP_EXCHANGE_MAX_KEY_SIZE / 2);
-	kvp_data->data.key_size = 2*(keylen + 1); /* utf16 encoding */
+				(wchar_t *) kvp_data->key,
+				(HV_KVP_EXCHANGE_MAX_KEY_SIZE / 2) - 2);
+	kvp_data->key_size = 2*(keylen + 1); /* utf16 encoding */
+
+copy_value:
 	valuelen = utf8s_to_utf16s(value, strlen(value), UTF16_HOST_ENDIAN,
-				(wchar_t *) kvp_data->data.value,
-				HV_KVP_EXCHANGE_MAX_VALUE_SIZE / 2);
-	kvp_data->data.value_size = 2*(valuelen + 1); /* utf16 encoding */
+				(wchar_t *) kvp_data->value,
+				(HV_KVP_EXCHANGE_MAX_VALUE_SIZE / 2) - 2);
+	kvp_data->value_size = 2*(valuelen + 1); /* utf16 encoding */
 
-	kvp_data->data.value_type = REG_SZ; /* all our values are strings */
-	icmsghdrp->status = HV_S_OK;
+	/*
+	 * 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;
@@ -257,11 +373,18 @@ void hv_kvp_onchannelcallback(void *context)
 	u64 requestid;
 
 	struct hv_kvp_msg *kvp_msg;
-	struct hv_kvp_msg_enumerate *kvp_data;
 
 	struct icmsg_hdr *icmsghdrp;
 	struct icmsg_negotiate *negop = NULL;
 
+	if (kvp_transaction.active) {
+		/*
+		 * We will defer processing this callback once
+		 * the current transaction is complete.
+		 */
+		kvp_transaction.kvp_context = context;
+		return;
+	}
 
 	vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE, &recvlen, &requestid);
 
@@ -276,29 +399,16 @@ void hv_kvp_onchannelcallback(void *context)
 				sizeof(struct vmbuspipe_hdr) +
 				sizeof(struct icmsg_hdr)];
 
-			kvp_data = &kvp_msg->body.kvp_enum_data;
-
-			/*
-			 * We only support the "get" operation on
-			 * "KVP_POOL_AUTO" pool.
-			 */
-
-			if ((kvp_msg->kvp_hdr.pool != KVP_POOL_AUTO) ||
-				(kvp_msg->kvp_hdr.operation !=
-				KVP_OP_ENUMERATE)) {
-				icmsghdrp->status = HV_E_FAIL;
-				goto callback_done;
-			}
-
 			/*
 			 * Stash away this global state for completing the
 			 * transaction; note transactions are serialized.
 			 */
+
 			kvp_transaction.recv_len = recvlen;
 			kvp_transaction.recv_channel = channel;
 			kvp_transaction.recv_req_id = requestid;
 			kvp_transaction.active = true;
-			kvp_transaction.index = kvp_data->index;
+			kvp_transaction.kvp_msg = kvp_msg;
 
 			/*
 			 * Get the information from the
@@ -316,8 +426,6 @@ void hv_kvp_onchannelcallback(void *context)
 
 		}
 
-callback_done:
-
 		icmsghdrp->icflags = ICMSGHDRFLAG_TRANSACTION
 			| ICMSGHDRFLAG_RESPONSE;
 
@@ -338,6 +446,14 @@ hv_kvp_init(struct hv_util_service *srv)
 		return err;
 	recv_buffer = srv->recv_buffer;
 
+	/*
+	 * 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.active = true;
+
 	return 0;
 }
 

include/linux/hyperv.h

@@ -119,6 +119,8 @@
  */
 
 #define REG_SZ 1
+#define REG_U32 4
+#define REG_U64 8
 
 enum hv_kvp_exchg_op {
 	KVP_OP_GET = 0,

tools/hv/hv_kvp_daemon.c

@@ -389,10 +389,16 @@ int main(void)
 			}
 			continue;
 
+		case KVP_OP_SET:
+		case KVP_OP_GET:
+		case KVP_OP_DELETE:
 		default:
 			break;
 		}
 
+		if (hv_msg->kvp_hdr.operation != KVP_OP_ENUMERATE)
+			goto kvp_done;
+
 		hv_msg = (struct hv_kvp_msg *)incoming_cn_msg->data;
 		key_name = (char *)hv_msg->body.kvp_enum_data.data.key;
 		key_value = (char *)hv_msg->body.kvp_enum_data.data.value;
@@ -454,6 +460,7 @@ int main(void)
 		 * already in the receive buffer. Update the cn_msg header to
 		 * reflect the key value that has been added to the message
 		 */
+kvp_done:
 
 		incoming_cn_msg->id.idx = CN_KVP_IDX;
 		incoming_cn_msg->id.val = CN_KVP_VAL;