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=-7.9 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,HK_RANDOM_FROM,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 4117EC388F7 for ; Thu, 22 Oct 2020 13:31:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D967E24178 for ; Thu, 22 Oct 2020 13:31:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2900123AbgJVNba (ORCPT ); Thu, 22 Oct 2020 09:31:30 -0400 Received: from mga18.intel.com ([134.134.136.126]:7583 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2895506AbgJVNb3 (ORCPT ); Thu, 22 Oct 2020 09:31:29 -0400 IronPort-SDR: /XPzOjJ6zcEjLKA50NUOXgl7YiY9L10KIPrAlG66/C4JYocoRM3gzJ3F9ITvouTeF2rFm/J5cN q7+Tg4caHcOA== X-IronPort-AV: E=McAfee;i="6000,8403,9781"; a="155311058" X-IronPort-AV: E=Sophos;i="5.77,404,1596524400"; d="scan'208";a="155311058" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Oct 2020 06:31:27 -0700 IronPort-SDR: ZtHX9vEE2nOZ4DgE3j62VO+vKT9O38aAHAtNNns8UiGdYTeYIXIJKbYDsIEkE3P8KdPxr+zMvO YohhWF1xuGEw== X-IronPort-AV: E=Sophos;i="5.77,404,1596524400"; d="scan'208";a="533968088" Received: from xiaoyaol-mobl.ccr.corp.intel.com (HELO [10.254.213.210]) ([10.254.213.210]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Oct 2020 06:31:25 -0700 Subject: Re: [PATCH] KVM: X86: Expose KVM_HINTS_REALTIME in KVM_GET_SUPPORTED_CPUID To: Paolo Bonzini , Wanpeng Li , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel References: <1603330475-7063-1-git-send-email-wanpengli@tencent.com> From: Xiaoyao Li Message-ID: <6ad94df6-9ecd-e364-296a-34ba41e938b1@intel.com> Date: Thu, 22 Oct 2020 21:31:23 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 10/22/2020 9:02 PM, Paolo Bonzini wrote: > On 22/10/20 03:34, Wanpeng Li wrote: >> From: Wanpeng Li >> >> Per KVM_GET_SUPPORTED_CPUID ioctl documentation: >> >> This ioctl returns x86 cpuid features which are supported by both the >> hardware and kvm in its default configuration. >> >> A well-behaved userspace should not set the bit if it is not supported. >> >> Suggested-by: Jim Mattson >> Signed-off-by: Wanpeng Li > > It's common for userspace to copy all supported CPUID bits to > KVM_SET_CPUID2, I don't think this is the right behavior for > KVM_HINTS_REALTIME. It reminds of X86_FEATURE_WAITPKG, which is added to supported CPUID recently as a fix but QEMU exposes it to guest only when "-overcommit cpu-pm" > (But maybe this was discussed already; if so, please point me to the > previous discussion). > > Paolo >