This page contains references to other pages describing how to use virtual machines with RTEMS for development and targeting. There are multiple ways to create VMs and multiple OSes just for creation of RTEMS development hosts.
The current applications that have been used to simulate machines in RTEMS development are:
The Simulators page contains information on using virtual machines for simulating a board.
The MinGW:Grub2:VMWare Development Environment Setup page offers information on setting up VMWare, Grub, MinGW and simulating a Windows virtual machine.
An RTEMS user has provided some scripts for setting up a VirtualBox development environment with Vagrant. Note, Vagrant scripts might be broken, a ticket has been submitted to fix it ticket #2488, so it's better to use RSB directly instead until it's fixed.