From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751832AbcGNG4h (ORCPT ); Thu, 14 Jul 2016 02:56:37 -0400 Received: from mail-wm0-f41.google.com ([74.125.82.41]:38885 "EHLO mail-wm0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751598AbcGNG41 (ORCPT ); Thu, 14 Jul 2016 02:56:27 -0400 Subject: Re: [PATCH v2 0/5] Add support for EPT execute only for nested hypervisors To: Bandan Das References: <1468361932-16580-1-git-send-email-bsd@redhat.com> <82db70ed-761e-0377-5417-acb64bed6cb6@redhat.com> <921eef54-f23b-cd90-8e20-a428a00a3297@redhat.com> Cc: kvm@vger.kernel.org, guangrong.xiao@linux.intel.com, kernellwp@gmail.com, linux-kernel@vger.kernel.org From: Paolo Bonzini Message-ID: <26006044-7096-63e5-8156-a15f001d8403@redhat.com> Date: Thu, 14 Jul 2016 08:56:24 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 13/07/2016 17:47, Bandan Das wrote: >>> I wanted to keep it the former way because "PT_PRESENT_MASK is equal to VMX_EPT_READABLE_MASK" >>> is an assumption all throughout. I wanted to use this section to catch mismatches. >> >> I think there's no such assumption anymore, actually. Can you double >> check? If there are any, that's where the BUILD_BUG_ON should be. > > What I meant is how they are the same bit. is_shadow_present_pte() is probably one > and another one is link_shadow_page() which already has a BUILD_BUG_ON(). You're right about link_shadow_page()! We probably should change the PT_PRESENT_MASK to shadow_present_mask there (and then readability in the EPT execonly case is still provided by shadow_user_mask). For is_shadow_present_pte() you have removed it in patch 1 though. Paolo