lua, 89 bytes

Result

AC

Duration

944ms

Code [DL]

h,w=io.read("n","n")
for y=1,h do print("*"..((y>1 and y<h)and" "or"*"):rep(w-2).."*")end

stdin

58
22

stdout

**********************
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
*                    *
**********************

stderr