Pavel Tatashin wrote on Mon, Jan 07, 2019: > I could not reproduce the problem. Did you suspend to memory between > wake ups? Does this time jump happen every time, even if your laptop > sleeps for a minute? I'm not sure I understand "suspend to memory between the wake ups". The full sequence is: - start a VM (just in case, I let it boot till the end) - suspend to memory (aka systemctl suspend) the host - after resuming the host, soft reboot the VM (login through serial/ssh/whatever and reboot or in the qemu console 'system_reset') I've just slept exactly one minute and reproduced again with the fedora stock kernel now (4.19.13-300.fc29.x86_64) in the VM. Interestingly I'm not getting the same offset between multiple reboots now despite not suspending again; but if I don't suspend I cannot seem to get it to give an offset at all (only tried for a few minutes; this might not be true) ; OTOH I pushed my luck further and even with a five seconds sleep I'm getting a noticeable offset on first VM reboot after resume: [ 0.000000] Hypervisor detected: KVM [ 0.000000] kvm-clock: Using msrs 4b564d01 and 4b564d00 [ 179.362163] kvm-clock: cpu 0, msr 13c01001, primary cpu clock [ 179.362163] clocksource: kvm-clock: mask: 0xffffffffffffffff max_cycles: 0x1cd42e4dffb, max_idle_ns: 881590591483 ns Honestly not sure what more information I could give, I'll try on some other hardware than my laptop (if I can get a server to resume after suspend through ipmi or wake on lan); but I don't have anything I could install ubuntu on to try their qemu's version... although I really don't want to believe that's the difference... Thanks, -- Dominique
