Open Source Summit + Embedded Linux Conference Europe 2020

We share our evaluation of KVM-based Type1 (or 1.5) hypervisor (KVM++) to discuss which option is the best for the community, showing the pros and cons of the implementation options. At the last KVM Forum, we showed a high-level architecture of KVM++, where we can isolate guest memory from the host except the areas for I/O buffers, in order to better protect and isolate guests. In terms of the implementation, one extreme is to run it as a KVM guest on top of a hypervisor that consists of KVM/mini-Linux. At the other end, we deprivilege it with almost everything passthrough except memory access. The former requires nested virtualization if KVM is used on the host Linux. The latter doesn’t. Those implementations can affect overhead and latency of the systems as well, and the implication and impacts can depend on the platform (i.e. client vs. server).