multiple master on avalon

For a project a Nios processor has to communicate with a PID-controller defined in VHDL

The PID controller will control the PWM IP core through the avalon interface where the PID controller is the master.

The NIOS processor will also function as a master on the avalon interface to communicate with the UART/ ethernet interface and some custom devices.

Setpoint must be changed in the PID controller by the NIOS processor, my question is:

How can this communication be achieved?

- Make a master and a slave connection for the controller where the master interface controls the pwm generator and the slave will receive some setpoints

- Multiple avalon interfaces??