linux-kernel - RE: [PATCH] x86/mce: Add Skylake quirk for patrol scrub reported errors

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <3908561D78D1C84285E8C5FCA982C28F7F670974@ORSMSX115.amr.corp.intel.com>
Date:   Tue, 16 Jun 2020 22:33:08 +0000
From:   "Luck, Tony" <tony.luck@...el.com>
To:     Borislav Petkov <bp@...en8.de>
CC:     "Song, Youquan" <youquan.song@...el.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] x86/mce: Add Skylake quirk for patrol scrub reported
 errors

> Two things: can that error type be detected when #MC gets raised, i.e., in
> do_machine_check() as part of scanning all banks?

If the BIOS option is left in the default setting, uncorrectable errors found
by the patrol scrubber are reported with a machine check. Those MSCOD
and MCACOD signatures are the same ... but that's not important because
MCi_STATUS.UC==1. So Linux doesn't need to jump through hoops to
"upgrade" the severity.

> If so, then the adjusting needs to happen inside mce_log().
So no, this adjust only needs to happen when polling the banks from
CMCI or periodic timer.

> Also, that assignment to the function pointer doesn't make much sense to
> me and I think you should do the vendor/family/model checking straight
> in a function adjust_mce_log() which gets called by whoever...

The point was to avoid the runtime test for CPU model on every error. But
this isn't a performance critical path, so we can refactor if you think that
looks cleaner.

There is some new set of validation tests running now to check the effectiveness
of this BIOS + OS change. So it may be a while before updated version is
posted.

Thanks

-Tony