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    SubjectRe: [kvm-devel] Guest kernel hangs in smp kvm for older kernels prior to tsc sync cleanup
    Ingo Molnar wrote:
    > * Avi Kivity <avi@qumranet.com> wrote:
    >
    >
    >> Avi Kivity wrote:
    >>
    >>> Testing shows wrmsr and rdtsc function normally.
    >>>
    >>> I'll try pinning the vcpus to cpus and see if that helps.
    >>>
    >>>
    >> It does.
    >>
    >
    > do we let the guest read the physical CPU's TSC? That would be trouble.
    >
    >

    vmx (and svm) allow us to add an offset to the physical tsc. We set it
    on startup to -tsc (so that an rdtsc on boot would return 0), and
    massage it on vcpu migration so that guest rdtsc is monotonic.

    The net effect is that tsc on a vcpu can experience large forward jumps
    and changes in rate, but no negative jumps.

    --
    error compiling committee.c: too many arguments to function



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