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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 B488AC3F2D1 for ; Mon, 2 Mar 2020 11:48:19 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8476B214DB for ; Mon, 2 Mar 2020 11:48:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8476B214DB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:59384 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j8jYY-0005GJ-NI for qemu-devel@archiver.kernel.org; Mon, 02 Mar 2020 06:48:18 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:37878) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j8jXu-0004o2-O1 for qemu-devel@nongnu.org; Mon, 02 Mar 2020 06:47:39 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j8jXt-00068b-1m for qemu-devel@nongnu.org; Mon, 02 Mar 2020 06:47:37 -0500 Received: from mga04.intel.com ([192.55.52.120]:26635) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j8jXs-00066R-PW for qemu-devel@nongnu.org; Mon, 02 Mar 2020 06:47:37 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 02 Mar 2020 03:47:30 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,507,1574150400"; d="scan'208";a="273688687" Received: from yli41-mobl1.ccr.corp.intel.com (HELO [10.249.199.10]) ([10.249.199.10]) by fmsmga002.fm.intel.com with ESMTP; 02 Mar 2020 03:47:29 -0800 Subject: Re: [PATCH v3 2/4] target/i386: Remove monitor from some CPU models To: Eduardo Habkost References: <20200212081328.7385-1-tao3.xu@intel.com> <20200212081328.7385-3-tao3.xu@intel.com> <20200228213909.GA481504@habkost.net> From: Tao Xu Message-ID: <06a6cd99-7d11-7eee-c337-c71e756fc53f@intel.com> Date: Mon, 2 Mar 2020 19:47:28 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200228213909.GA481504@habkost.net> Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 192.55.52.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "pbonzini@redhat.com" , "qemu-devel@nongnu.org" , "rth@twiddle.net" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2/29/2020 5:39 AM, Eduardo Habkost wrote: > On Wed, Feb 12, 2020 at 04:13:26PM +0800, Tao Xu wrote: >> Add new version of Snowridge, Denverton, Opteron_G3, EPYC, and Dhyana >> CPU model to uremove MONITOR/MWAIT featre. >> >> After QEMU/KVM use "-overcommit cpu-pm=on" to expose MONITOR/MWAIT >> (commit id 6f131f13e68d648a8e4f083c667ab1acd88ce4cd), the MONITOR/MWAIT >> feature in these CPU model is unused. >> >> Signed-off-by: Tao Xu > > What exactly is the problem you are trying to fix? > > No CPU model will ever have monitor=on set by default with KVM, > because kvm_default_props has a monitor=off element. > Maybe it is not a fix. For example, when we boot a guest with Denverton cpu model, guest cannot detect MONITOR/MWAIT and boot with no warning, because of "monitor=off" by default. The MONITOR/MWAIT feature in these CPU model is unused,but no harm. I am wondering if we should remove it from existing CPU models.