KVM Forum 2020

Virtio has been originally designed as a VM guest to hypervisor interface. As it became ubiquitious virtio hardware offload schemes began to pop up. These are typically designed to perform well with existing Virtio drivers without modifying guests. We are however finding out that to maximise performance, interface changes can be benefitial. Interestingly, as CPU technology changes, some of these become benefitial for guest to hypervisor communication, too. This talk will discuss changes in the Virtio specification for the benefit of new CPU and offload hardware: some of them already accepted for the next specification version, some still under discussion. Open questions will be presented in the hope to generate discussion.