Drivers: hv: Add new message types to enhance KVP

Add additional KVP (Key Value Pair) protocol  messages to
enhance KVP functionality for Linux guests on Hyper-V. As part of this,
patch define an explicit version negoitiation message.

Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hv/hv_kvp.c

@@ -78,7 +78,7 @@ kvp_register(void)
 
 	if (msg) {
 		kvp_msg = (struct hv_kvp_msg *)msg->data;
-		version = kvp_msg->body.kvp_version;
+		version = kvp_msg->body.kvp_register.version;
 		msg->id.idx =  CN_KVP_IDX;
 		msg->id.val = CN_KVP_VAL;
 
@@ -122,7 +122,8 @@ kvp_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
 		 * to the host. But first, cancel the timeout.
 		 */
 		if (cancel_delayed_work_sync(&kvp_work))
-			kvp_respond_to_host(data->data.key, data->data.value,
+			kvp_respond_to_host(data->data.key,
+					 data->data.value,
 					!strlen(data->data.key));
 	}
 }

include/linux/hyperv.h

@@ -149,19 +149,43 @@ struct hv_kvp_exchg_msg_value {
 	__u32 key_size;
 	__u32 value_size;
 	__u8 key[HV_KVP_EXCHANGE_MAX_KEY_SIZE];
-	__u8 value[HV_KVP_EXCHANGE_MAX_VALUE_SIZE];
+	union {
+		__u8 value[HV_KVP_EXCHANGE_MAX_VALUE_SIZE];
+		__u32 value_u32;
+		__u64 value_u64;
+	};
 } __attribute__((packed));
 
 struct hv_kvp_msg_enumerate {
 	__u32 index;
 	struct hv_kvp_exchg_msg_value data;
 } __attribute__((packed));
 
+struct hv_kvp_msg_get {
+	struct hv_kvp_exchg_msg_value data;
+};
+
+struct hv_kvp_msg_set {
+	struct hv_kvp_exchg_msg_value data;
+};
+
+struct hv_kvp_msg_delete {
+	__u32 key_size;
+	__u8 key[HV_KVP_EXCHANGE_MAX_KEY_SIZE];
+};
+
+struct hv_kvp_register {
+	__u8 version[HV_KVP_EXCHANGE_MAX_KEY_SIZE];
+};
+
 struct hv_kvp_msg {
 	struct hv_kvp_hdr	kvp_hdr;
 	union {
-		struct hv_kvp_msg_enumerate     kvp_enum_data;
-		char    kvp_version[HV_KVP_EXCHANGE_MAX_KEY_SIZE];
+		struct hv_kvp_msg_get		kvp_get;
+		struct hv_kvp_msg_set		kvp_set;
+		struct hv_kvp_msg_delete	kvp_delete;
+		struct hv_kvp_msg_enumerate	kvp_enum_data;
+		struct hv_kvp_register		kvp_register;
 	} body;
 } __attribute__((packed));
 

tools/hv/hv_kvp_daemon.c

@@ -378,7 +378,7 @@ int main(void)
 			 * Driver is registering with us; stash away the version
 			 * information.
 			 */
-			p = (char *)hv_msg->body.kvp_version;
+			p = (char *)hv_msg->body.kvp_register.version;
 			lic_version = malloc(strlen(p) + 1);
 			if (lic_version) {
 				strcpy(lic_version, p);