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

Borislav Petkov
2022-08-23T18:32:14Z

On Tue, Aug 02, 2022 at 01:50:53PM -0600, Jane Chu wrote:
> With Commit 7917f9cdb503 ("acpi/nfit: rely on mce->misc to determine
> poison granularity") that changed nfit_handle_mce() callback to report
> badrange according to 1ULL << MCI_MISC_ADDR_LSB(mce->misc), it's been
> discovered that the mce->misc LSB field is 0x1000 bytes, hence injecting
> 2 back-to-back poisons and the driver ends up logging 8 badblocks,
> because 0x1000 bytes is 8 512-byte.

What I'm missing from this text here is, what *is* the mce->misc LSB
field in human speak? What does that field denote?

What effect does that field have on error injection?

And so on.

> Dan Williams noticed that apei_mce_report_mem_error() hardcode
> the LSB field to PAGE_SHIFT instead of consulting the input
> struct cper_sec_mem_err record. So change to rely on hardware whenever
> support is available.

Rely on hardware? You're changing this to rely on what the firmware
reports.

That mem_err thing comes from a BIOS table AFAICT.

...

Thx.

--
Regards/Gruss,
Boris.