title: Can perf tool provide list of system calls being invoked inside VM?
body: <p>I am trying to monitor all system calls being invoked inside a virtual machine from host OS. I tried this at host:</p>
  
  <pre><code>perf trace -a | grep qemu
  </code></pre>
  
  <p>This gives an output like this:</p>
  
  <pre><code>0.000 ( 0.000 ms): qemu-system-x8/7511  ... [continued]: poll()) = 0 Timeout
  10.060 (10.043 ms): qemu-system-x8/7511 poll(ufds: 0x7f5d300008f8, nfds: 20, timeout_msecs: 10                ) = 0 Timeout
  20.161 (10.079 ms): qemu-system-x8/7511 poll(ufds: 0x7f5d300008f8, nfds: 20, timeout_msecs: 10                ) = 0 Timeout
  30.226 (10.044 ms): qemu-system-x8/7511 poll(ufds: 0x7f5d300008f8, nfds: 20, timeout_msecs: 10                ) = 0 Timeout
  </code></pre>
  
  <p>Can anyone explain what are these calls that are shown in this output? Are these system calls being invoked inside virtual machine? or are these invoked by host OS itself in response to the calls invoked by VM?</p>