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SubjectRe: [RESEND] x86/bus_lock: Don't assume the init value of DEBUGCTLMSR.BUS_LOCK_DETECT to be zero
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On 8/2/2022 6:51 PM, Ingo Molnar wrote:
>
> * Chenyi Qiang <chenyi.qiang@intel.com> wrote:
>
>> It's possible that BIOS/firmware has set DEBUGCTLMSR_BUS_LOCK_DETECT, or
>> this kernel has been kexec'd from a kernel that enabled bus lock
>> detection.
>>
>> Disable bus lock detection explicitly if not wanted.
>
> Makes sense.
>
> Just curious: in what circumstances does the BIOS/firmware set
> DEBUGCTLMSR_BUS_LOCK_DETECT? Does it use it, or does it enable it for some
> spurious reason, without really using the feature? (Assuming you are aware
> of instances where this happened - or was this simply a hypothetical?)

Yes, It's just a hypothetical for BIOS/firmware. Kexec is the real case
I met with this problem.

>
> Thanks,
>
> Ingo

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