linux-kernel - Re: [PATCH v7] x86/mce: retrieve poison range from hardware

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Message-ID: <2cff660e-3e08-2cfc-adee-27c2dfdfd5db@oracle.com>
Date:   Fri, 26 Aug 2022 22:11:36 +0000
From:   Jane Chu <jane.chu@...cle.com>
To:     Borislav Petkov <bp@...en8.de>,
        Dan Williams <dan.j.williams@...el.com>
CC:     "tony.luck@...el.com" <tony.luck@...el.com>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "hch@....de" <hch@....de>,
        "nvdimm@...ts.linux.dev" <nvdimm@...ts.linux.dev>
Subject: Re: [PATCH v7] x86/mce: retrieve poison range from hardware

On 8/26/2022 11:09 AM, Borislav Petkov wrote:
> On Fri, Aug 26, 2022 at 10:54:31AM -0700, Dan Williams wrote:
>> How about:
>>
>> ---
>>
>> When memory poison consumption machine checks fire,
>> mce-notifier-handlers like nfit_handle_mce() record the impacted
>> physical address range.
> 
> ... which is reported by the hardware in the MCi_MISC MSR.
> 
>> The error information includes data about blast
>> radius, i.e. how many cachelines did the hardware determine are
>> impacted.
> 
> Yap, nice.
> 
>> A recent change, commit 7917f9cdb503 ("acpi/nfit: rely on
>> mce->misc to determine poison granularity"), updated nfit_handle_mce()
>> to stop hard coding the blast radius value of 1 cacheline, and instead
>> rely on the blast radius reported in 'struct mce' which can be up to 4K
>> (64 cachelines).
>>
>> It turns out that apei_mce_report_mem_error() had a similar problem in
>> that it hard coded a blast radius of 4K rather than checking the blast
> 
> s/checking/reading/
> 
>> radius in the error information. Fix apei_mce_report_mem_error() to
> 
> s/in/from/
> 
>> convey the proper poison granularity.
>>
>> ---
> 
> Yap, that's a lot better.
> 
> Thanks!


Got it and points taken.  Thank you both, Boris and Dan.

v8 coming up.

thanks,
-jane