KVM Forum 2019

The ivshmem device is a simple way to interconnect a number of VMs and let them exchange data and events without much hypervisor involvement. In fact, this is a common pattern in many hypervisor, specifically in embedded. But our current design has a number of shortcomings, primarily around life-cycle management. And it has always been a stepchild, lacking even an upstream kernel driver.

This talk will present our effort to improve ivshmem. The new design gained essential missing features as well as a number of nice add-ons like uni-directional memory regions or optimized UIO interrupt handling. And it has been written to be applicable on QEMU as well as other hypervisors, e.g. Jailhouse.

The talk will furthermore present a prototype that stacks virtio over an ivshmem link, providing a lightweight backend-frontend channel that does not require virtio awareness in the hypervisor.