Recently, I’ve noticed strange hangs of KVM VMs on a custom VMM. As it fits the topic of this blog, I thought I make the issue more googleable. Until we dive into the issue, we have to set the scene a bit. The Scene Consider that we want to run a KVM vCPU on Linux, but we want it to unconditionally exit after 1ms regardless of what the guest does. To achieve this, we can create a CLOCK_MONOTONIC timer with timer_create that sends a signal to the thread that runs the vCPU (via SIGEV_THREAD_I...
