Abstract: A processing system may include a service operating system (OS) and a guest virtual machine (VM). The service OS may be a host OS or an OS in a service VM, for instance. The guest VM may have a physical address space. In one embodiment, a pseudo-device driver in the service OS causes an address within the physical address space of the guest VM to be mapped to an address within a virtual address space of a user level monitor (ULM) running on top of the service OS. When an operation that involves the physical address space of the guest VM (e.g., a direct memory access (DMA) operation requested by the guest VM, an interrupt triggered by the guest VM, etc.) is detected, the ULM may use its virtual address space to access the physical address space of the guest VM. Other embodiments are described and claimed.