>> >> + kvm_get_msr(vcpu, MSR_IA32_TIME_STAMP_COUNTER, >> + &vcpu->hv_clock.last_tsc); >> + >> + ktime_get_ts(&ts); >> + vcpu->hv_clock.now_ns = ts.tv_nsec + (NSEC_PER_SEC * >> (u64)ts.tv_sec); + vcpu->hv_clock.wc_sec = get_seconds(); >> >> I am even thinking we have to disable interrupt between these lines, >> otherwise guest wall clock may see backward time source when >> calculating the delta TSC since last vcpu->hv_clock.now_ns update. >> > > That's true. While we do need to handle vcpu migration and > descheduling, the code sequence you note needs to be as atomic as > possible. >
Yes VCPU migration is another issue. Since the physical platform TSC is totally different across migration, so we can't expose host TSC to guest. For KVM, it should be simple to just use guest_TSC (=HOST_TSC + offset). thanks, eddie ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
