Among other disclosed subject matter, a system includes a secure execution domain configured to execute trusted processes. The system also includes a hardware virtualization component in the secure execution domain and configured to implement a virtual machine. The virtual machine is a hardware virtualization of a data processing apparatus and includes a shared virtual memory device and a guest software application coupled to the shared virtual memory device. The system also includes a trusted process in the secure execution domain, separate from the virtual machine and coupled to the shared virtual memory device. The trusted process is configured to communicate with the guest software application through the shared virtual memory device. Communication with the guest software application includes secure communication.