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 X-Spam-Level: X-Spam-Status: No, score=-8.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CC0ACC352A2 for ; Thu, 6 Feb 2020 20:23:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A0BA321927 for ; Thu, 6 Feb 2020 20:23:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="CYmgcQJG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727827AbgBFUXv (ORCPT ); Thu, 6 Feb 2020 15:23:51 -0500 Received: from mail-qk1-f194.google.com ([209.85.222.194]:38155 "EHLO mail-qk1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727526AbgBFUXv (ORCPT ); Thu, 6 Feb 2020 15:23:51 -0500 Received: by mail-qk1-f194.google.com with SMTP id 21so6896186qki.5; Thu, 06 Feb 2020 12:23:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=c2iCNtrYC2+Mdzvmrw5+MQ+tkR8a1GggRuPCY2Z5Feg=; b=CYmgcQJGVE41pT4E5lTZdnBm+LY0hAHEJjKseOWehnmNuRG78MqlF3dRJWZhfjVSVM WTgC20KgVF4TzeMTMOXx187W5tnu5/HWndCMOYTWF9xxDP/1jx0KVWb7ADGk/w17qe8t 5jiE9ItqE/x1VXqVdGE5e3OXvQixydL1zelw4O6imOjoAtYaUP64UBmUxGg/8P+qfvSq HPlGYvPQUblb2y/TsN5lkyC3YdUGkI2wD/dkYqYbEpyv3krrN/cSA3js/ku2IAtuw2BU NaocVy/pLXo27wbSxnE8pl/iFQFA5NKTAqir60Egp/jc34c9cYKDGrxOZMMPISI1APu3 uqhQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:date:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=c2iCNtrYC2+Mdzvmrw5+MQ+tkR8a1GggRuPCY2Z5Feg=; b=OSZdtVjRfOOY0MtK/PksE0E0bz9xsJuho/NBFcEtLzb4A5I6SV0zrV5rW8rAuUV/iM ZF309LTu6KAScFOe6kTmCyIuq50W6u53/Dnlu8+8jS/XQcwtgGAun/TJF02ZhCD1hwWg 7z/F6teugdF57LEn4XDfEnYEnoeoE8IWbGWiuOfZ0tY/lr2YGT6YGbz3UujjvvlUDVw/ NIBjfqqZLk/fnoFSW7vAtEao+yiKutAxqwJUqS0+eW174rhdbEMCIuWIP5sfddEzdiuG 6b0/guGR2sYqmKswUvLe9Kb8LRrJbw+Eo1rxv7L0BvaO4rEp1jjhtMUmRdJX9NstRhoP /seg== X-Gm-Message-State: APjAAAX+gVIAm5tTCB0fnlDqJHOBWY9efXEN80KM0f3RHJ3OcnfiZsxN nqMSbnkyOcrbMQnP7AC0zN4= X-Google-Smtp-Source: APXvYqyFgNLaYiSgs+zCYQ+mCBBuWLsboa2rWQ1/9lHdrY252n0AynntA2jYdDxFZLSJrIaFfCmu9Q== X-Received: by 2002:a37:a451:: with SMTP id n78mr4091402qke.481.1581020629653; Thu, 06 Feb 2020 12:23:49 -0800 (PST) Received: from rani.riverdale.lan ([2001:470:1f07:5f3::b55f]) by smtp.gmail.com with ESMTPSA id x19sm206271qtm.47.2020.02.06.12.23.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Feb 2020 12:23:49 -0800 (PST) From: Arvind Sankar X-Google-Original-From: Arvind Sankar Date: Thu, 6 Feb 2020 15:23:47 -0500 To: Xiaoyao Li Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , hpa@zytor.com, Paolo Bonzini , Sean Christopherson , Andy Lutomirski , tony.luck@intel.com, peterz@infradead.org, fenghua.yu@intel.com, x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 3/8] x86/split_lock: Cache the value of MSR_TEST_CTRL in percpu data Message-ID: <20200206202346.GA2742055@rani.riverdale.lan> References: <20200206070412.17400-1-xiaoyao.li@intel.com> <20200206070412.17400-4-xiaoyao.li@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200206070412.17400-4-xiaoyao.li@intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Thu, Feb 06, 2020 at 03:04:07PM +0800, Xiaoyao Li wrote: > Cache the value of MSR_TEST_CTRL in percpu data msr_test_ctrl_cache, > which will be used by KVM module. > > It also avoids an expensive RDMSR instruction if SLD needs to be context > switched. > > Suggested-by: Sean Christopherson > Signed-off-by: Xiaoyao Li > --- > arch/x86/include/asm/cpu.h | 2 ++ > arch/x86/kernel/cpu/intel.c | 19 ++++++++++++------- > 2 files changed, 14 insertions(+), 7 deletions(-) > > diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h > index ff567afa6ee1..2b20829db450 100644 > --- a/arch/x86/include/asm/cpu.h > +++ b/arch/x86/include/asm/cpu.h > @@ -27,6 +27,8 @@ struct x86_cpu { > }; > > #ifdef CONFIG_HOTPLUG_CPU > +DECLARE_PER_CPU(u64, msr_test_ctrl_cache); > + Why does this depend on HOTPLUG_CPU?