RE: JAZZCNC

It looks pretty concave to me, I guess if you had your machine set with the Z low at the top and high at the bottom then it would be, anyway it's a simple task to do file>replace the G2>G3 and vise versa.

RE: Jonathan

Yes I forgot to mention he would need a ball nose tool with radius less than 5 17/32.

You could do it longitudinally with a normal endmill but you'd be massively wearing the tooth corners out and it would take practically a million passes to get smooth.
The ideal way todo this would be with a fly cutter however you'd need a horizontal mill, unless you could fix the work piece vertically.