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    SubjectRe: [PATCH] perf/x86: Disable uncore on virtualized CPU.
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    On Tue, Aug 21, 2012 at 05:08:37PM +0800, Yan, Zheng wrote:
    >> From: "Yan, Zheng" <zheng.z.yan@intel.com>
    >>
    >> Initializing uncore PMU on virtualized CPU may hang the kernel.
    >> This is because kvm does not emulate the entire hardware. Thers
    >> are lots of uncore related MSRs, making kvm enumerate them all
    >> is a non-trival task. So just disable uncore on virtualized CPU.

    On Tue, Aug 21, 2012 at 5:31 PM, Andi Kleen <andi@firstfloor.org> wrote:
    > I'm not sure cpu_has_hypervisor is reliable enough for this.
    > Better find out why it hangs and fix that.
    >
    > Early rdmsrls should be rdmsrl_safe()
    > Early writes in the driver should check if anything was written,
    > and if not then disable itself.

    It's unfortunate that the changelog does not include any reference to
    the actual thread this was discussed in:

    http://www.mail-archive.com/kvm@vger.kernel.org/msg77524.html


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