Messages in this thread | | | Date | Mon, 25 Oct 2021 14:14:28 +0800 | Subject | Re: [PATCH] x86/bus_lock: Don't assume the init value of DEBUGCTLMSR.BUS_LOCK_DETECT to be zero | From | Chenyi Qiang <> |
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On 10/20/2021 1:05 AM, Sean Christopherson wrote: > On Wed, Sep 01, 2021, Chenyi Qiang 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. > > This feels like the kernel should explicitly zero out the entire MSR somewhere > in the generic boot flow. E.g. something like this somewhere. >
Yes. Meanwhile, I think kernel code prefers to explicitly set/clear the control bit according to the parameter. Maybe both changes should be applied.
> #ifndef CONFIG_X86_DEBUGCTLMSR > if (boot_cpu_data.x86 < 6) > return; > #endifa > > wrmsrl(MSR_IA32_DEBUGCTLMSR, 0); >
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