  Virtualization plays an essential role in providing security to computational
systems by isolating execution environments. Many software solutions, called
hypervisors, have been proposed to provide virtualization capabilities.
However, only a few were designed for being deployed at the edge of the
network, in devices with fewer computation resources when compared with servers
in the Cloud. Among the few lightweight software that can play the hypervisor
role, seL4 stands out by providing a small Trusted Computing Base and formally
verified components, enhancing its security. Despite today being more than a
decade with seL4 microkernel technology, its existing userland and tools are
still scarce and not very mature. Over the last few years, the main effort has
been put into increasing the maturity of the kernel itself and not the tools
and applications that can be hosted on top. Therefore, it currently lacks
proper support for a full-featured userland Virtual Machine Monitor, and the
existing one is quite fragmented. This article discusses the potential
directions to a standard VMM by presenting our view of design principles and
feature set needed. This article does not intend to define a standard VMM, we
intend to instigate this discussion through the seL4 community.
