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    SubjectRe: [PATCH 16/17] TSC reset compensation
    On Mon, Jun 14, 2010 at 09:34:18PM -1000, Zachary Amsden wrote:
    > Attempt to synchronize TSCs which are reset to the same value. In the
    > case of a reliable hardware TSC, we can just re-use the same offset, but
    > on non-reliable hardware, we can get closer by adjusting the offset to
    > match the elapsed time.
    >
    > Signed-off-by: Zachary Amsden <zamsden@redhat.com>
    > ---
    > arch/x86/kvm/x86.c | 34 ++++++++++++++++++++++++++++++++--
    > 1 files changed, 32 insertions(+), 2 deletions(-)
    >
    > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
    > index 8e836e9..cedb71f 100644
    > --- a/arch/x86/kvm/x86.c
    > +++ b/arch/x86/kvm/x86.c
    > @@ -937,14 +937,44 @@ static inline void kvm_request_guest_time_update(struct kvm_vcpu *v)
    > set_bit(KVM_REQ_CLOCK_SYNC, &v->requests);
    > }
    >
    > +static inline int kvm_tsc_reliable(void)
    > +{
    > + return (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) &&
    > + boot_cpu_has(X86_FEATURE_NONSTOP_TSC) &&
    > + !check_tsc_unstable());
    > +}
    > +
    why can't we re-use vmware TSC_RELIABLE flag?




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