Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754127Ab2FLUhM (ORCPT ); Tue, 12 Jun 2012 16:37:12 -0400 Received: from s15943758.onlinehome-server.info ([217.160.130.188]:59250 "EHLO mail.x86-64.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753938Ab2FLUhJ (ORCPT ); Tue, 12 Jun 2012 16:37:09 -0400 Date: Tue, 12 Jun 2012 22:37:30 +0200 From: Borislav Petkov To: "H. Peter Anvin" Cc: Peter Zijlstra , Stephane Eranian , linux-kernel@vger.kernel.org, andi@firstfloor.org, mingo@elte.hu, ming.m.lin@intel.com, "Yu, Fenghua" Subject: Re: [PATCH] perf/x86: check ucode before disabling PEBS on SandyBridge Message-ID: <20120612203730.GE11137@aftab.osrc.amd.com> References: <20120607071531.GA4849@quad> <4FD78BE6.4060207@zytor.com> <20120612190720.GA11137@aftab.osrc.amd.com> <1339529614.31548.104.camel@twins> <20120612194900.GC11137@aftab.osrc.amd.com> <4FD7A687.3040500@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4FD7A687.3040500@zytor.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1340 Lines: 36 On Tue, Jun 12, 2012 at 01:28:55PM -0700, H. Peter Anvin wrote: > On 06/12/2012 12:49 PM, Borislav Petkov wrote: > > > > Also, I'd assume we need some of the current functionality to be able to > > load ucode without rebooting the box. > > > > Yes, the basic idea is that we'll keep the ucode around anyway so we can > feed it to hotplug CPUs or S3 resume. If the ucode is updated from > userspace we'd replace the in-memory copy and load it into the CPUs. You say CPUs, i.e. plural. What is your take on loading ucode on a single core, i.e. the /sys/devices/system/cpu/cpuX/microcode/reload interface? Do you guys need to load ucode only system-wide or can you stomach per-core loads? I want to disable it (or even remove it, modulo the whole userspace compat blah blah) on AMD. Also, if we do system-wide, can we have a single sysfs node where we give the new ucode from userspace instead of per-cpu files? -- 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@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/