Re: [RESEND] x86/bus_lock: Don't assume the init value of DEBUGCTLMSR.BUS_LOCK_DETECT to be zero

[Ingo Molnar]

* Chenyi Qiang <chenyi.qiang@xxxxxxxxx> 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?)

Thanks,

	Ingo