From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932396AbdKDQy3 (ORCPT ); Sat, 4 Nov 2017 12:54:29 -0400 Received: from mail-wm0-f52.google.com ([74.125.82.52]:53841 "EHLO mail-wm0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751991AbdKDQy1 (ORCPT ); Sat, 4 Nov 2017 12:54:27 -0400 X-Google-Smtp-Source: ABhQp+QmiPYOr6HMF50VSrkoZ++tVDI2ntMW9P0M1GoTK2H2ZAlyjpUKl4tTjIGMYET293DIyr9vlA== Subject: Re: [PATCH RFC 00/10] Intel EPT-Based Sub-page Write Protection Support. To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, rkrcmar@redhat.com, ravi.sahita@intel.com References: <20171104001243.GA81548@dazhang1-ssd.sh.intel.com> From: Paolo Bonzini Message-ID: Date: Sat, 4 Nov 2017 17:54:20 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <20171104001243.GA81548@dazhang1-ssd.sh.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/11/2017 01:12, Yi Zhang wrote: >> > Adding Ravi, > > Does anyone have further comments on current implementation, it is a > important feature in our next generation chip-set. What matters is not the feature, but the use case; without a use case, there is no point in including code for SPP in KVM. KVM doesn't use VMFUNC or #VE for example, because they are not necessary. SPP may become useful once we have the introspection interface. Or, if another hypervisor uses it, support for nested SPP may be useful (for example we support nested VMFUNC and should get nested #VE sooner or later, even though the features are not used on bare metal). Right now, however, supporting SPP does not seem to be particularly important honestly. Paolo