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

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Message-ID: <80eea4f7-bb1e-ebb9-37db-9317b8d9c28f@linux.intel.com>
Date:   Mon, 22 Aug 2022 09:28:31 -0400
From:   "Liang, Kan" <kan.liang@...ux.intel.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     acme@...hat.com, linux-kernel@...r.kernel.org,
        alexander.shishkin@...ux.intel.com, ak@...ux.intel.com,
        Jianfeng Gao <jianfeng.gao@...el.com>
Subject: Re: [RESEND PATCH] perf/x86/intel: Fix unchecked MSR access error for
 Alder Lake N



On 2022-08-19 10:38 a.m., Peter Zijlstra wrote:
> On Thu, Aug 18, 2022 at 11:15:30AM -0700, kan.liang@...ux.intel.com wrote:
>> From: Kan Liang <kan.liang@...ux.intel.com>
>>
>> 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