From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: 2 CPU Conformance Issue in KVM/x86 Date: Mon, 09 Mar 2015 20:33:08 +0100 Message-ID: <54FDF574.1020102@redhat.com> References: <54F58471.7020906@redhat.com> <54FDD39C.9060908@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit To: Avi Kivity , Nadav Amit , KVM list , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= Return-path: Received: from mail-wg0-f45.google.com ([74.125.82.45]:40794 "EHLO mail-wg0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750741AbbCITdO (ORCPT ); Mon, 9 Mar 2015 15:33:14 -0400 Received: by wghk14 with SMTP id k14so30914328wgh.7 for ; Mon, 09 Mar 2015 12:33:13 -0700 (PDT) In-Reply-To: <54FDD39C.9060908@gmail.com> Sender: kvm-owner@vger.kernel.org List-ID: On 09/03/2015 18:08, Avi Kivity wrote: > Is the issue emulating a higher MAXPHYADDR on the guest than is > available on the host? I don't think there's any need to support that. No, indeed. The only problem is that the failure mode is quite horrible (you get a triple fault, possibly while the guest is running). If you need that, disable EPT. :) > Emulating a lower setting on the guest than is available on the host is, > I think, desirable. Whether it would work depends on the relative > priority of EPT misconfiguration exits vs. page table permission faults. Yes, that's doable. Paolo