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

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Message-ID: <YwkMQsUn7BLPi5mU@zn.tnic>
Date:   Fri, 26 Aug 2022 20:09:06 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Dan Williams <dan.j.williams@...el.com>
Cc:     Jane Chu <jane.chu@...cle.com>,
        "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 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!

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette