How to collect VM exit numbers in KVM

How to Collect VM Exit Numbers in KVM

VM exits occur when a virtual machine needs the hypervisor’s attention. Monitoring these can help debug performance issues.

The Command

cat /sys/kernel/debug/kvm/exits

KVM in 2026

In 2026, KVM remains the standard for Linux virtualization. For more detailed tracing, administrators use perf or ftrace:
perf record -e kvm:* -a
This allows you to see not just the number of exits, but the specific reasons (e.g., EXIT_REASON_HLT, EXIT_REASON_IO_INSTRUCTION), which is crucial for optimizing high-performance VMs.