From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linutronix.de (146.0.238.70:993) by crypto-ml.lab.linutronix.de with IMAP4-SSL for ; 29 Jun 2018 08:26:32 -0000 Received: from mx2.suse.de ([195.135.220.15] helo=mx1.suse.de) by Galois.linutronix.de with esmtps (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1fYoje-00036C-OP for speck@linutronix.de; Fri, 29 Jun 2018 10:26:31 +0200 Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id CCBCBACCD for ; Fri, 29 Jun 2018 08:26:21 +0000 (UTC) Date: Fri, 29 Jun 2018 10:26:17 +0200 From: Borislav Petkov Subject: [MODERATED] Re: Re: [patch V4 13/13] x86/apic: Ignore secondary threads if nosmt=force Message-ID: <20180629082617.GA3752@zn.tnic> References: <20180620201907.304694346@linutronix.de> <20180620201933.588840902@linutronix.de> <9a4cea33-05a7-b6d9-7f49-692603bd047f@linux.intel.com> MIME-Version: 1.0 In-Reply-To: <9a4cea33-05a7-b6d9-7f49-692603bd047f@linux.intel.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable To: speck@linutronix.de List-ID: On Thu, Jun 28, 2018 at 03:13:11PM -0700, speck for Dave Hansen wrote: > > If machine-check exceptions are disabled, the logical > > processors enter the shutdown state and assert the IERR# signal. When > > enabling machine-check exceptions, the MCE flag in control register > > CR4 should be set for each logical processor. If only we were able to set MCG_STATUS_LMCES on all relevant CPUs and disable this MCE broadcasting insanity... Ok, question: what exactly does the hw/microcode do on an offlined logical CPU: does it test CR4.MCE first and assert that IERR# or does it look at MCG_CTL/MCi_CTL too so that we can try to disable MCE reporting on those offlined cores? There must be some recommendation about what BIOS should be doing when *it* causes an MCE during its init phase and the other cores are not up. Or does it have its own #MC handler and then disables everything before handoff to the OS? Hmmm. --=20 Regards/Gruss, Boris. SUSE Linux GmbH, GF: Felix Imend=C3=B6rffer, Jane Smithard, Graham Norton, HR= B 21284 (AG N=C3=BCrnberg) --=20