linux-kernel - Re: [patch 2/2] x86: mce: Implement cmci poll mode for intel machines

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]

Date:	Wed, 6 Jun 2012 11:04:15 +0200
From:	Borislav Petkov <bp@...64.org>
To:	Chen Gong <gong.chen@...ux.intel.com>
Cc:	Borislav Petkov <bp@...64.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	LKML <linux-kernel@...r.kernel.org>, tony.luck@...el.com,
	x86@...nel.org, Peter Zijlstra <peterz@...radead.org>
Subject: Re: [patch 2/2] x86: mce: Implement cmci poll mode for intel machines

On Wed, Jun 06, 2012 at 09:36:52AM +0800, Chen Gong wrote:
> Yes, I am just afraid similar situation happening when injecting MCEs
> or poll timer running too fast, which is like a pseduo CMCI storm.
> Maybe similar logic behind CMCI_STORM can be used there.

Poll timer on !Intel fires once every 5 minutes and halves the interval
when it detects a valid MCE.

I still don't think this is an issue if you poll only on single CPUs -
I think you need the throttling because, as Tony explained earlier, the
CMCI interrupt runs on _all_ CPUs and I can see how that can be hurting
performance.

CMCI on AMD (or, rather, our version of it) runs only on the CPU which
sees the error so I don't think we need throttling there, unless real
life proves me otherwise.

So, the whole CMCI deal should be Intel-only (for now, at least) and it
shouldn't be touching generic MCE code.

Thanks.

-- 
Regards/Gruss,
Boris.

Advanced Micro Devices GmbH
Einsteinring 24, 85609 Dornach
GM: Alberto Bozzo
Reg: Dornach, Landkreis Muenchen
HRB Nr. 43632 WEEE Registernr: 129 19551
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/