From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S938846AbcJXMfq (ORCPT ); Mon, 24 Oct 2016 08:35:46 -0400 Received: from mail.skyhub.de ([78.46.96.112]:34114 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S938449AbcJXMfo (ORCPT ); Mon, 24 Oct 2016 08:35:44 -0400 Date: Mon, 24 Oct 2016 11:35:10 +0200 From: Borislav Petkov To: sonofagun@openmailbox.org Cc: linux-kernel@vger.kernel.org, Nikos Barkas Subject: Re: [PATCH] x86/AMD: Apply erratum 688 on machines without a BIOS fix Message-ID: <20161024093510.od57fbvn5rsgxcua@pd.tnic> References: <20161021230143.4wwop3giwwuzbkpr@pd.tnic> <52b804e35d9e82a46b35409586475ee2@openmailbox.org> <20161022141229.4us4iqy7dhgulssn@pd.tnic> <1651fbd1076bc365aef52a804d1ffbad@openmailbox.org> <20161023095722.n77oefpmttzvzqqc@pd.tnic> <4b27ef7e7a256a6c9341cf182ebceef7@openmailbox.org> <20161023172530.buklz6ir56dmbvu7@pd.tnic> <78e7e3b73f5ad8af44710a0e104301cb@openmailbox.org> <20161023213939.d55y5yc2megztnyr@pd.tnic> <6ce351cda59585ecdfdce361d885811e@openmailbox.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <6ce351cda59585ecdfdce361d885811e@openmailbox.org> User-Agent: NeoMutt/20161014 (1.7.1) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 24, 2016 at 02:38:06PM +0300, sonofagun@openmailbox.org wrote: > The patch is not equivalent to the original. As a result it behaves > differently. To be specific, using dmesg I get the expected value from the > affected MSR with the original patch. With the latest patch, patching of the > MSR occurs after dmesg prints the MSR information. That is why I thought it > did nothing. Gah, that "show_msr" is crap - it gets issued too early and we can - and we do - set MSRs later too. Oh and it prints only the BSP. I should probably rip it out - there's msr-tools for that which is much better. > rdmsr --all 0xc0011021 returns the expected results on all CPUs with both > patches. I have the impression that the system boots slower because the fix > is applied later compared to the original patch. Could be - setting those bits 3 in 14 in that MSR is probably disabling some hw features which may impact performance. > Could you please use perf and tell me what values do you get at perf > branch-misses right after boot on your ON-B0 box? Launching firefox with > only one tab gives you similar numbers? Sure, give me the exact command you're executing so that I can do it here. > If you need anything more, feel free to ask. Out of pure interest: do you remember how exactly you did reproduce this issue? Thanks. -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply.