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    SubjectRe: [PATCH v12 09/11] x86/tsc: prepare for early sched_clock
    On Fri, Jun 29, 2018 at 09:30:10AM +0200, Thomas Gleixner wrote:
    > On Thu, 28 Jun 2018, Pavel Tatashin wrote:
    > > On Thu, Jun 28, 2018 at 11:23 AM Thomas Gleixner <tglx@linutronix.de> wrote:
    > > Hi Thomas,
    > >
    > > In addition to above, we have xen hvm:
    > >
    > > setup_arch()
    > > ...
    > > init_hypervisor_platform();
    > > x86_init.hyper.init_platform();
    > > xen_hvm_guest_init()
    > > xen_hvm_init_time_ops();
    >
    > Duh. Missed that completely.
    >
    > > ...
    > > tsc_early_delay_calibrate();
    > > tsc_khz = x86_platform.calibrate_tsc(); == xen_tsc_khz()
    > > ...
    > >
    > > Which works early.
    > >
    > > So, what should we do with xen, which seems to be the only platform
    > > that would provide different tsc frequency early and late, because of
    > > different calibration method?
    >
    > Fix it? I have no idea why XEN has two variants of the scheme and I neither
    > have a clue why the KVM clock stuff is late.

    Added Juergen (Xen).
    >
    > Thanks,
    >
    > tglx
    >

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