From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DE3C4C54EE9 for ; Mon, 19 Sep 2022 14:31:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229803AbiISObl (ORCPT ); Mon, 19 Sep 2022 10:31:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59376 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229830AbiISObk (ORCPT ); Mon, 19 Sep 2022 10:31:40 -0400 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7400F19C06; Mon, 19 Sep 2022 07:31:38 -0700 (PDT) Received: from zn.tnic (p200300ea9733e79d329c23fffea6a903.dip0.t-ipconnect.de [IPv6:2003:ea:9733:e79d:329c:23ff:fea6:a903]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 686171EC0230; Mon, 19 Sep 2022 16:31:32 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1663597892; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=aOFLwruiG67vJseMHd1aWtOXV4a+xdwAVmA/Tm3D62A=; b=MF31u7W0nciM6gYqCIXOPlJ8PFI3wvqW3+y/53XxRIsto/JsN4N9wwAsYownZNlxxJirxK kPEgRIyry9VZN8H5PB/O+2qeF/5ohzv9ZKiaOKNQktePrMBligl79aCa7043gwsOXH1iDd TEDaelCyuNn5racZYOJ3D5E8Wd/QHbU= Date: Mon, 19 Sep 2022 16:31:32 +0200 From: Borislav Petkov To: Maxim Levitsky Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Pawan Gupta , Ingo Molnar , Josh Poimboeuf , Namhyung Kim , Tony Luck , Paolo Bonzini , "H. Peter Anvin" , Arnaldo Carvalho de Melo , Thomas Gleixner , Alexander Shishkin , Tim Chen , "David S. Miller" , Dave Hansen , "Chang S. Bae" , Jane Malalane , Kees Cook , Kan Liang , Peter Zijlstra , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , Herbert Xu , Jiri Olsa , Mark Rutland , linux-perf-users@vger.kernel.org, "open list:CRYPTO API" Subject: Re: [PATCH v2 1/5] perf/x86/intel/lbr: use setup_clear_cpu_cap instead of clear_cpu_cap Message-ID: References: <20220718141123.136106-1-mlevitsk@redhat.com> <20220718141123.136106-2-mlevitsk@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220718141123.136106-2-mlevitsk@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org On Mon, Jul 18, 2022 at 05:11:19PM +0300, Maxim Levitsky wrote: > clear_cpu_cap(&boot_cpu_data) is very similar to setup_clear_cpu_cap > except that the latter also sets a bit in 'cpu_caps_cleared' which > later clears the same cap in secondary cpus, which is likely > what is meant here. > > Fixes: 47125db27e47 ("perf/x86/intel/lbr: Support Architectural LBR") > > Reviewed-by: Kan Liang > Signed-off-by: Maxim Levitsky > --- > arch/x86/events/intel/lbr.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c > index 13179f31fe10fa..b08715172309a7 100644 > --- a/arch/x86/events/intel/lbr.c > +++ b/arch/x86/events/intel/lbr.c > @@ -1860,7 +1860,7 @@ void __init intel_pmu_arch_lbr_init(void) > return; > > clear_arch_lbr: > - clear_cpu_cap(&boot_cpu_data, X86_FEATURE_ARCH_LBR); > + setup_clear_cpu_cap(X86_FEATURE_ARCH_LBR); setup_clear_cpu_cap() has a very specific purpose - see apply_forced_caps(). This whole call sequence is an early_initcall() which is way after the whole CPU features picking apart happens. So what is actually this fixing? -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette