From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753412AbcGVIlI (ORCPT ); Fri, 22 Jul 2016 04:41:08 -0400 Received: from mx3-phx2.redhat.com ([209.132.183.24]:34593 "EHLO mx3-phx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752566AbcGVIk5 (ORCPT ); Fri, 22 Jul 2016 04:40:57 -0400 Date: Fri, 22 Jul 2016 04:40:55 -0400 (EDT) From: Paolo Bonzini To: Bandan Das Cc: kvm@vger.kernel.org, rkrcmar@redhat.com, linux-kernel@vger.kernel.org Message-ID: <266030483.9634373.1469176855327.JavaMail.zimbra@redhat.com> In-Reply-To: References: <1469053536-11130-1-git-send-email-bsd@redhat.com> <1469053536-11130-5-git-send-email-bsd@redhat.com> Subject: Re: [PATCH 4/4] nvmx: check for shadow vmcs check on entry MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [10.4.164.1, 10.5.100.50] X-Mailer: Zimbra 8.0.6_GA_5922 (ZimbraWebClient - FF43 (Mac)/8.0.6_GA_5922) Thread-Topic: nvmx: check for shadow vmcs check on entry Thread-Index: /qfV1trsTyFp9xOXcmzOdSWxgU2Ygg== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Paolo Bonzini writes: > > > On 21/07/2016 00:25, Bandan Das wrote: > >> vmentry should check whether the vmcs provided by > >> the guest hypervisor is a shadow vmcs and fail. > > > > How can this happen, since vmptrld checks the revision_id as you said > > below? > > This is more of a change that adheres to the spec > (26.1 Basic VM-Entry Checks); the failure path > is slightly different compared to vmptrld though. > It's small and harmless but I am ok if you prefer dropping it. Do you mean that this could happen if the VMCS is modified by L1 after VMPTRLD? That makes sense, but with David Matlack's change to cache the VMCS it wouldn't be possible to trigger it anymore. Paolo