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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 1ABDBC433E0 for ; Thu, 21 May 2020 08:40:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EDACC20671 for ; Thu, 21 May 2020 08:40:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="PVfvBYL3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728713AbgEUIk2 (ORCPT ); Thu, 21 May 2020 04:40:28 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:51182 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728688AbgEUIk1 (ORCPT ); Thu, 21 May 2020 04:40:27 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1590050426; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=dOW7B8nLICvI2QSpCheBsPrgf3sHzyca7R6p70npClk=; b=PVfvBYL3IvPrWAu7uE4r2EPHM2Hs6B3n7fODfLQoJpcd/xO1y25CvKblu/ipyTOuX8XSN+ 7JuhtzgX1FWgzjT34wA/AxCHKTbrReqvWI3HNeAPTB8vbaDZ8Pil33J8k4hlDnY9fOCpZf xLam97TB4CzBlVYopVnFESRge9NznuQ= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-5-Ul_2ZY9wPPOZwDNe8oNJIg-1; Thu, 21 May 2020 04:40:24 -0400 X-MC-Unique: Ul_2ZY9wPPOZwDNe8oNJIg-1 Received: by mail-wm1-f71.google.com with SMTP id g10so2441775wme.0 for ; Thu, 21 May 2020 01:40:24 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=dOW7B8nLICvI2QSpCheBsPrgf3sHzyca7R6p70npClk=; b=i/Q3T/Wd/Frp1mTXPpu8szPZhAbxBmyf9WUSyIreXDBQ9Jhsw3+7kYI+t3WREvMVK1 IS7lkG1tCybjBP/YxXhLImqXx6DUR1uJpI3oSKLK0w1p1m8UMmrewtCeQaxvdnh06iPh cBWGPBMb3SFelWGuKm/2ipbp52Pc096mmosySvw4S113k/EVEr7+xg4vspkjukfZz97+ OUbWgc774kfj2wM1oQxZdFq/RrG276PxmFlXTWPTjnkwnBbSGxbJ8L1fV99ePiH3S4Au Hnvi82kmysYzX6hBBX7ZzNn1ztBMnhszKVKGaf4xDML5Dpsj9zngMREy7Wtot8Tg7Peh nybw== X-Gm-Message-State: AOAM532apkAK9NFQntReKJeeeg4SlEZz+s8eKai/Zd1KXri4TwZJ3RXS iBRRai9KZ+5vV1a3EAFlKk+L5S4DZRO/uWm9O4MlofxlN70UMkQII2gryb63abMxwGUnGBJyZkk AQ7//l0rbVn+vsBDPXWEqr6J4 X-Received: by 2002:a7b:c193:: with SMTP id y19mr7935733wmi.158.1590050422639; Thu, 21 May 2020 01:40:22 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxukfKVUk2qDd/EsYglDEd1qglHM6q51pYRYREmlhXPiE9KQzqCcOX8bFxDroTR47/pAlGPuw== X-Received: by 2002:a7b:c193:: with SMTP id y19mr7935709wmi.158.1590050422401; Thu, 21 May 2020 01:40:22 -0700 (PDT) Received: from [192.168.178.58] ([151.30.94.134]) by smtp.gmail.com with ESMTPSA id x18sm5169145wru.72.2020.05.21.01.40.21 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 21 May 2020 01:40:21 -0700 (PDT) Subject: Re: [PATCH 2/2] kvm/x86: don't expose MSR_IA32_UMWAIT_CONTROL unconditionally To: Tao Xu , Xiaoyao Li Cc: Maxim Levitsky , kvm@vger.kernel.org, linux-kernel@vger.kernel.org References: <20200520160740.6144-1-mlevitsk@redhat.com> <20200520160740.6144-3-mlevitsk@redhat.com> <81228a0e-7797-4f34-3d6d-5b0550c10a8f@intel.com> <6c99b807-fe67-23b5-3332-b7200bf5d639@intel.com> From: Paolo Bonzini Message-ID: <3642373d-8d1d-de80-d3db-e835a8f29449@redhat.com> Date: Thu, 21 May 2020 10:40:21 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <6c99b807-fe67-23b5-3332-b7200bf5d639@intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21/05/20 08:44, Tao Xu wrote: > > I am sorry, I mean: > By default, we don't expose WAITPKG to guest. For QEMU, we can use > "-overcommit cpu-pm=on" to use WAITPKG. But UMONITOR, UMWAIT and TPAUSE are not NOPs on older processors (which I should have checked before committing your patch, I admit). So you have broken "-cpu host -overcommit cpu-pm=on" on any processor that doesn't have WAITPKG. I'll send a patch. Paolo