Handling Complex Guest Exits with eBPF

Explore the potential of using eBPF programs to handle complex guest exits in KVM virtualization environments. This 32-minute KVM Forum talk delves into the challenges of processing non-trivial guest exits, such as device emulation and hypercall processing, which traditionally require bouncing back to the VMM in userspace. Examine the latency costs associated with this approach and learn about existing mitigation efforts like vhost and IRQFD. Discover the difficulties in generalizing in-kernel handling of complex guest exits beyond virtio (vhost) and consider how eBPF programs could offer a solution. Engage in a discussion about the feasibility and future possibilities of this approach for improving virtualization performance and efficiency.