RTOS on one core and Android on another core

Hello All, 

We are designing one device based with 2 cores of ARM Cortex-A15 Processor. We have to run RTOS and Android on the same processor. as described below.

Approach 1: Running both OSes as Guest OS on top of Hypervisor 

Approach 2: Run RTOS on one core  and Android on other core. 

Can you please suggest me which approach is better and how it can be achieved. 

Best Regards

Naidu A