We have recently added Mulit-Queue support to our SR-IOV solution. Multi-Queue (MQ) uses 3 interrupts, non MQ only uses 2; however the code still requests 3. I've asked engineering to look into this and see if we can only reqeust 2 if only going to use 2.
To use MQ, and all 3 interrupts, when you compile both the PF and VF use CFLAGS_EXTRA="-DIXGBE_ENABLE_VF_MQ".
Hope this helps,
Patrick