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    SubjectRe: [patch 14/21] Xen-paravirt: Add XEN config options and disable unsupported config options.
    Zachary Amsden wrote:
    > Jeremy Fitzhardinge wrote:
    >> The XEN config option enables the Xen paravirt_ops interface, which is
    >> installed when the kernel finds itself running under Xen. (By some
    >> as-yet fully defined mechanism, implemented in a future patch.)
    >> Xen is no longer a sub-architecture, so the X86_XEN subarch config
    >> option has gone.
    >> The disabled config options are:
    >> - PREEMPT: Xen doesn't support it
    >> - HZ: set to 100Hz for now, to cut down on VCPU context switch rate.
    >> This will be adapted to use tickless later.
    >> - kexec: not yet supported
    >> Signed-off-by: Jeremy Fitzhardinge <>
    >> Signed-off-by: Ian Pratt <>
    >> Signed-off-by: Christian Limpach <>
    >> Signed-off-by: Chris Wright <>
    > We do support different HZ values, although 100HZ is actually
    > preferable for us, so I don't object to that.

    Ditto for kvm.

    > PREEMPT is supported by us, but not as tested as I would like, so I
    > also don't object to dropping it for generic paravirt guests - Rusty -
    > Avi any objections to dropping preempt in terms of lguest/KVM
    > paravirtualization?

    I don't have any objections myself, but Ingo (who has done the bulk of
    the kvm paravirt work; cc'ed) uses PREEMPT_RT, so he will certainly object.

    > Paravirt-ops definitely needs a hook for kexec, although we should not
    > disable kexec for the natively booted paravirt-ops. Eric - is there a
    > way to disable it at runtime?

    kvm paravirt should work correctly with kexec.

    > We do support the doublefault task gate, and it would be good to keep
    > it, but I can't complain so much if it is gone from generic paravirt
    > kernels for now, because it is non-essential, and generally fatal
    > anyway. We do need it for native boots of paravirt-ops kernels,
    > however, so turning off the config option still needs to be revisited.

    kvm doesn't support task gates (a task switch will immediately kill the

    error compiling committee.c: too many arguments to function

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      Last update: 2007-02-18 12:35    [W:0.026 / U:2.932 seconds]
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