title: How KVM handle physical interrupt?
body: <p>i am working on KVM optimization for VMs' IO. I have read the KVM codes, usually all the physical interrupt will cause the VMexit and enter into KVM. Then the host's IDT will handle the corresponding physical interrupt. My question is that how KVM decide whether to inject a virtual interrupt into the guest or not? and under what situation it will inject a virtual interrupt to the guest? </p>
  
  <p>Thanks</p>