On 22/01/2016 12:31, Andrey Smetanin wrote: >> >> Sometimes the TSC is detected to be unstable and Linux switches to >> another clocksource. At least in that case you can get a write to the >> TSC page while the guest is running. > Sorry, now I got it, you mean host TSC is unstable and we should mark > guest tsc page invalid. Now I understand please ignore my prev. message.
No problem. Anyhow yes, this is what I meant: a host write to the TSC page, not a guest write to the TSC page MSR. Usually it happens only at migration time to update the sequence---which I believe your patch wasn't doing either. But if we tie TSC page updates to kvm_gen_update_masterclock, we get that for free when the migration destination calls the KVM_SET_CLOCK ioctl. Paolo
