Re: [RESEND PATCH] perf/x86/intel: Fix unchecked MSR access error for Alder Lake N

[Liang, Kan]

On 2022-08-19 10:38 a.m., Peter Zijlstra wrote:
> On Thu, Aug 18, 2022 at 11:15:30AM -0700, kan.liang@xxxxxxxxxxxxxxx wrote:
>> From: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
>>
>> For some Alder Lake N machine, the below unchecked MSR access error may be
>> triggered.
>>
>> [ 0.088017] rcu: Hierarchical SRCU implementation.
>> [ 0.088017] unchecked MSR access error: WRMSR to 0x38f (tried to write
>> 0x0001000f0000003f) at rIP: 0xffffffffb5684de8 (native_write_msr+0x8/0x30)
>> [ 0.088017] Call Trace:
>> [ 0.088017] <TASK>
>> [ 0.088017] __intel_pmu_enable_all.constprop.46+0x4a/0xa0
> 
> FWIW, I seem to get the same error when booting KVM on my ADL. I'm
> fairly sure the whole CPUID vs vCPU thing is a trainwreck.

We will enhance the CPUID to address the issues. Hopefully, we can have
them supported in the next generation.


Thanks,
Kan