From mboxrd@z Thu Jan 1 00:00:00 1970 From: Borislav Petkov Subject: Re: [Patch] MCE, APEI: Don't enable CMCI when Firmware First mode is set in HEST for corrected machine checks Date: Sun, 12 May 2013 16:47:08 +0200 Message-ID: <20130512144708.GA5589@pd.tnic> References: <1367881102.4518.68.camel@oc3432500282.ibm.com> <20130506232537.GF22041@pd.tnic> <1367897566.4518.83.camel@oc3432500282.ibm.com> <20130507131946.GC7633@pd.tnic> <1367941214.4518.90.camel@oc3432500282.ibm.com> <20130508212237.GI30955@pd.tnic> <3908561D78D1C84285E8C5FCA982C28F2DA47E5E@ORSMSX101.amr.corp.intel.com> <20130508221501.GK30955@pd.tnic> <3908561D78D1C84285E8C5FCA982C28F2DA47F03@ORSMSX101.amr.corp.intel.com> <1368208744.4518.182.camel@oc3432500282.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Received: from mail.skyhub.de ([78.46.96.112]:44534 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754176Ab3ELOrM (ORCPT ); Sun, 12 May 2013 10:47:12 -0400 Content-Disposition: inline In-Reply-To: <1368208744.4518.182.camel@oc3432500282.ibm.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Max Asbock Cc: "Luck, Tony" , "linux-acpi@vger.kernel.org" , "Huang, Ying" , "naveen.n.rao@in.ibm.com" , "ananth@in.ibm.com" , "lcm@linux.vnet.ibm.com" , lkml And I was wondering why this is not reaching lkml. Fixed. On Fri, May 10, 2013 at 10:59:04AM -0700, Max Asbock wrote: > I'll try to summarize the situation: > > We proposed two iterations of a patch that would parse HEST for a > Corrected Machine Check entry and cause CMCI to be disabled if the > Firmware First flag was found to be on in that entry. > Several shortcomings of this approach were subsequently pointed out: > a) Disabling CMCI doesn't go far enough. If the firmware wants to > control corrected machine checks then we shouldn't even be polling the > MCi_STATUS registers. Therefore we need to disable CMCI and disable > polling if FF is set. > > b) The firmware may take over only a subset of the possible corrected > machine check events. If we turn off CMCI (and polling) for all banks we > may miss out on some types of errors. Therefore we should not > indiscriminately disable CMCI on all banks. > > The question arose whether the APEI spec allows to specify individual > machine check banks which fall under FF control. The answer appears to > be 'possibly'. The Corrected Machine Check (CMC) structure defined in > the APEI spec allows for a list of Machine Check Bank structures which > could be used to designate a set of banks falling under FF control. > However, the spec is silent on how the list of Machine Check Bank > structures in the CMC structure is be used. > > Further steps in this endeavor may depend on the interpretation of the > CMC structure in APEI an whether we can specify individual machine check > banks that fall under FF control. Right, so we need a complete solution where all FF banks are excluded from polling. The question is, does the CMC table in APEI enumerate *all* FF banks or we need to parse something else too. -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. --