A zero-copy fast channel for inter-guest and guest-host communication using VirtIO-serial

Virtualization technology, in the computer architecture domain, is characterized by the property of sharing system resources among the virtual machines (VMs) hosted on a physical server. Isolation is also a characteristic property of virtualization, which prevents the guest operating system running on these virtual machines to be aware of each other's presence on the same host. The isolation property of virtualization is essential for the security of co-resident VMs. However, this becomes a bottleneck, when some of the co-resident VMs need to communicate with each other for accomplishing a common task. A trivial method to communicate would be using a TCP/IP channel. This does accomplish the goal of communication, albeit with unsatisfactory performance, efficiency and security. In view of this, we need a mechanism which maintains the isolation characteristic of virtualization and yet provides a fast, efficient and secure channel for communication. In this paper, we discuss virtIO-serial, a fast channel for communication on KVM, an open source hypervisor based on the Linux kernel.