[libvirt] Logging VM startup and shutdown

When troubleshooting a libvirt system the most obvious question I face is when a given VM started and stopped. The only way I've been able to obtain this information is by setting log_level = 1 in libvirtd.conf, which turns on the firehose, generating an enormous amount of output. I then have to sift through the logs for magic strings like "virExecWithHook" to see when a VM started, and "Shutting down VM" to see when a VM stopped. Is there no concise message that indicates a VM starting up? "virExecWithHook" doesn't exactly jump out. I'd consider starting up and shutting down a VM to be at least worth an info-level message in the log. I monkeyed with the log_filters setting but I couldn't figure out how to filter those two strings. Any hints? --Ed