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    SubjectRe: [PATCH 1/2] boot: ignore early NMIs
    On 03/12/2012 01:04 PM, H. Peter Anvin wrote:
    > On 03/12/2012 01:01 PM, Eric W. Biederman wrote:
    >>
    >> The basic problem is which source do we block this at? How many
    >> sources are their? And architecturally last I looked x86 no longer
    >> has a NMI disable EFI and similar systems want to get away without
    >> a CMOS legacy clock because designers so often get them wrong.
    >>
    >
    > On all processors which have an LAPIC you can block all NMI sources at
    > the LAPIC. I think it's safe to assume that if you don't have an LAPIC
    > -- an ancient system by now -- you have port 70h.
    >

    One thing: *disabling* the LAPIC will allow external NMIs coming in on
    LINT1 through, since the LAPIC in the disabled state tries to mimic the
    no-LAPIC configuration. So I don't think you want to disable LAPIC as
    much as disable the interrupt vectors within.

    -hpa



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