"It's __ you!" (2,2)
(Other definitions for upto that I've seen before include "Engaged in, maybe mischief" , "Engaged in - no good?" , "Capable of or engaged in" , "To the time that" , "As far as; ready for" .)
(Other definitions for up to that I've seen before include "working at > till" , "Plotting" , "Capable of" , "Engaged in doing" , "Incumbent upon" .)