From mboxrd@z Thu Jan 1 00:00:00 1970 From: Muli Ben-Yehuda Subject: Re: [PATCH] VT-d: Fix iommu map page for mmio pages Date: Sun, 28 Sep 2008 09:07:53 +0300 Message-ID: <20080928060753.GD7239@il.ibm.com> References: <0122C7C995D32147B66BF4F440D3016301BE2C10@pdsmsx415.ccr.corp.intel.com> <48DB6777.7070709@redhat.com> <0122C7C995D32147B66BF4F440D3016301C7D0EB@pdsmsx415.ccr.corp.intel.com> <48DB98FD.3000307@redhat.com> <0122C7C995D32147B66BF4F440D3016301C7D0FF@pdsmsx415.ccr.corp.intel.com> <48DBA40A.7030508@redhat.com> <20080925211423.GC6788@il.ibm.com> <48DC07DC.2010201@codemonkey.ws> <20080926235730.GE9118@il.ibm.com> <48DE09DF.2050400@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Anthony Liguori , kvm@vger.kernel.org, Amit Shah , "Kay, Allen M" , Ben-Ami Yassour1 To: Avi Kivity Return-path: Received: from mtagate4.de.ibm.com ([195.212.29.153]:34286 "EHLO mtagate4.de.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750897AbYI1GIW (ORCPT ); Sun, 28 Sep 2008 02:08:22 -0400 Received: from d12nrmr1607.megacenter.de.ibm.com (d12nrmr1607.megacenter.de.ibm.com [9.149.167.49]) by mtagate4.de.ibm.com (8.13.8/8.13.8) with ESMTP id m8S68KfJ150480 for ; Sun, 28 Sep 2008 06:08:20 GMT Received: from d12av01.megacenter.de.ibm.com (d12av01.megacenter.de.ibm.com [9.149.165.212]) by d12nrmr1607.megacenter.de.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id m8S68KUD3858502 for ; Sun, 28 Sep 2008 08:08:20 +0200 Received: from d12av01.megacenter.de.ibm.com (loopback [127.0.0.1]) by d12av01.megacenter.de.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m8S68JvF012028 for ; Sun, 28 Sep 2008 08:08:20 +0200 Content-Disposition: inline In-Reply-To: <48DE09DF.2050400@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Sat, Sep 27, 2008 at 01:24:31PM +0300, Avi Kivity wrote: >> I strongly disagree. You are advocating something that is >> potentially unsafe---for the sake of code simplicity?! I am >> advocating caution in what we let an *untrusted* guest do. > > Why would it be unsafe? Because on at least one machine letting a device DMA to the same address as another device's MMIO region caused the machine to reboot. Cheers, Muli -- The First Workshop on I/O Virtualization (WIOV '08) Dec 2008, San Diego, CA, http://www.usenix.org/wiov08/ xxx SYSTOR 2009---The Israeli Experimental Systems Conference http://www.haifa.il.ibm.com/conferences/systor2009/