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

Dan Williams
2022-08-26T17:54:45Z

Borislav Petkov wrote:
> On Thu, Aug 25, 2022 at 04:29:47PM +0000, Jane Chu wrote:
> > Tony has replied.
>
> Do you really think that I can't look up what field means?
>
> What I said was
>
> "What I'm missing from this text here is... "
>
> IOW, what I'm trying to say is, you should formulate your commit message
> better, more human-friendly. Right now it reads like for insiders only.
> But that's not its purpose.
>
> Do you catch my drift?

How about:

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When memory poison consumption machine checks fire,
mce-notifier-handlers like nfit_handle_mce() record the impacted
physical address range. The error information includes data about blast
radius, i.e. how many cachelines did the hardware determine are
impacted. 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
radius in the error information. Fix apei_mce_report_mem_error() to
convey the proper poison granularity.

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