How to set Kv filter plugin to keep spaces in value

[Darrenliu (Darren)]

Hi everyone :
I am new to learn ELK, then I'm challenges in using kv filter now.
Let me make it brief, the following is one part of my dataset:

s1Label=Rule cs2Label=URL Category cs3Label=Virtual System

then my configure is

filter {
kv{ 
       field_split=>" "
       value_split=>"="   }

the result I got was

"s1Label":"Rule" 
"cs2Label":"URL" 
"cs3Label":"Virtual" 

How can I get the values including space and set field_split=>" " at same time ?
Or is there any other filter to do that except grok , because all data is not arranged in order.
Anyway, I want data to separarate key, value as mentioned below by kv filter

"s1Label":"Rule" 
"cs2Label":"URL Category" 
"cs3Label":"Virtual System"

Please help me or give me some ideas for it, I'll appreciate. Thank a lot !