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=-5.3 required=3.0 tests=BAYES_00, 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 38888C4338F for ; Tue, 10 Aug 2021 14:37:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 12B8060FC4 for ; Tue, 10 Aug 2021 14:37:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240965AbhHJOiK (ORCPT ); Tue, 10 Aug 2021 10:38:10 -0400 Received: from mga04.intel.com ([192.55.52.120]:48120 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239555AbhHJOiE (ORCPT ); Tue, 10 Aug 2021 10:38:04 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10072"; a="213059215" X-IronPort-AV: E=Sophos;i="5.84,310,1620716400"; d="scan'208";a="213059215" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Aug 2021 07:37:25 -0700 X-IronPort-AV: E=Sophos;i="5.84,310,1620716400"; d="scan'208";a="515865447" Received: from yilonggu-mobl.ccr.corp.intel.com (HELO localhost) ([10.249.175.101]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Aug 2021 07:37:21 -0700 Date: Tue, 10 Aug 2021 22:37:16 +0800 From: Yu Zhang To: Paolo Bonzini Cc: Sean Christopherson , Wei Huang , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com Subject: Re: [PATCH v2 1/3] KVM: x86: Allow CPU to force vendor-specific TDP level Message-ID: <20210810143716.daz5p3mf5bbeyp74@linux.intel.com> References: <20210809035806.5cqdqm5vkexvngda@linux.intel.com> <20210809042703.25gfuuvujicc3vj7@linux.intel.com> <73bbaac0-701c-42dd-36da-aae1fed7f1a0@amd.com> <20210809064224.ctu3zxknn7s56gk3@linux.intel.com> <20210810074037.mizpggevgyhed6rm@linux.intel.com> <0ac41a07-beeb-161e-9e5d-e45477106c01@redhat.com> <20210810110031.h7vaqf3nljwm3wym@linux.intel.com> <998dca9a-84b6-20ee-2646-3eb58df0b8a0@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <998dca9a-84b6-20ee-2646-3eb58df0b8a0@redhat.com> User-Agent: NeoMutt/20171215 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, Aug 10, 2021 at 02:47:27PM +0200, Paolo Bonzini wrote: > On 10/08/21 13:00, Yu Zhang wrote: > > I guess it's because, unlike EPT which are with either 4 or 5 levels, NPT's > > level can range from 2 to 5, depending on the host paging mode... > > Yes, on Linux that will be one of 3/4/5 based on host paging mode, and it > will apply to all N_CR3... > > > But shadow EPT does not have such annoyance. Is above understanding correct? > > ... Right, because shadow EPT cannot have less than 4 levels, and it can > always use 4 levels if that's what L1 uses. Interesting. :) Thanks a lot for the explanation! B.R. Yu