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[2620:137:e000::1:18]) by mx.google.com with ESMTPS id ls15-20020a17090b350f00b001c6fd746c71si5688683pjb.119.2022.04.06.08.10.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 06 Apr 2022 08:10:58 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) client-ip=2620:137:e000::1:18; Authentication-Results: mx.google.com; dkim=pass header.i=@alien8.de header.s=dkim header.b=OPQ0p0uQ; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=alien8.de Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id AA8ED3AD1CB; Wed, 6 Apr 2022 05:59:49 -0700 (PDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231331AbiDFNBf (ORCPT + 99 others); Wed, 6 Apr 2022 09:01:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53488 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231250AbiDFNBK (ORCPT ); Wed, 6 Apr 2022 09:01:10 -0400 Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AA4A85BC1C8 for ; Wed, 6 Apr 2022 02:26:32 -0700 (PDT) Received: from zn.tnic (p2e55dff8.dip0.t-ipconnect.de [46.85.223.248]) (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 90CD81EC0426; Wed, 6 Apr 2022 11:25:47 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1649237147; 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=4cZSb3cc+Gu90BQrKaaggIaclA4W6uCeg9JKu/+H7fE=; b=OPQ0p0uQnCJZWG8yZP+JQxzuxibM2vDmCkRqvV7WvCxeAkvhBxP8DukTYbfViuL2uAcrg3 x2geai0zDRVlcnAML5np+1n5PyMLnBRdmY5gS1NfXiuPuE3FlfUmmbYyRV6ODwWIirGymO tPatFAlJLZ/RWM2xExOCiuDIpyft8VU= Date: Wed, 6 Apr 2022 11:25:49 +0200 From: Borislav Petkov To: Wyes Karny Cc: linux-kernel@vger.kernel.org, Lewis.Carroll@amd.com, Mario.Limonciello@amd.com, gautham.shenoy@amd.com, Ananth.Narayan@amd.com, bharata@amd.com, len.brown@intel.com, x86@kernel.org, tglx@linutronix.de, mingo@redhat.com, dave.hansen@linux.intel.com, hpa@zytor.com, peterz@infradead.org, chang.seok.bae@intel.com, keescook@chromium.org, metze@samba.org, zhengqi.arch@bytedance.com, mark.rutland@arm.com Subject: Re: [PATCH] x86: Prefer MWAIT over HALT on AMD processors Message-ID: References: <20220405130021.557880-1-wyes.karny@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RDNS_NONE,SPF_HELO_NONE,T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 06, 2022 at 11:44:52AM +0530, Wyes Karny wrote: > If x86_FEATURE_ZEN is set and X86_FEATURE_MWAIT is not set or has > X86_BUG_MONITOR then it won't return correct value. Can that ever happen on Zen uarch? Also, what does this mean: "allow MWAIT early on."? -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette