From mboxrd@z Thu Jan 1 00:00:00 1970 From: Muli Ben-Yehuda Subject: Re: [PATCH] [RESEND] VT-d: Fix iommu map page for mmio pages Date: Thu, 2 Oct 2008 15:09:06 +0300 Message-ID: <20081002120906.GE7289@il.ibm.com> References: <0122C7C995D32147B66BF4F440D3016301C7D130@pdsmsx415.ccr.corp.intel.com> <48E4B707.5060702@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org, "Kay, Allen M" , "Yang, Sheng" , Anthony Liguori , Amit Shah , Ben-Ami Yassour1 To: Avi Kivity Return-path: Received: from mtagate4.de.ibm.com ([195.212.29.153]:43663 "EHLO mtagate4.de.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753249AbYJBMJl (ORCPT ); Thu, 2 Oct 2008 08:09:41 -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 m92C9dKQ141572 for ; Thu, 2 Oct 2008 12:09:39 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 m92C9dXC2367644 for ; Thu, 2 Oct 2008 14:09:39 +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 m92C9Zdt026511 for ; Thu, 2 Oct 2008 14:09:35 +0200 Content-Disposition: inline In-Reply-To: <48E4B707.5060702@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Thu, Oct 02, 2008 at 02:56:55PM +0300, Avi Kivity wrote: > Han, Weidong wrote: >> From 61028d958dc7c57ee02de32ea89b025dccb9650d Mon Sep 17 00:00:00 2001 >> From: Weidong Han >> Date: Thu, 25 Sep 2008 23:32:02 +0800 >> Subject: [PATCH] Map mmio pages into VT-d page table >> >> Assigned device could DMA to mmio pages, so also need to map mmio pages >> into VT-d page table. >> >> > > Well, Muli says at least on one machine this allows on guest to kill > the host. What are we doing with this? > > If it's a hardware bug which is planned to be fixed (or is already > fixed), great, but I need to know. Unfortunately I don't have access to the machine any more. We did spend some time perusing the PCIe spec on this point, and although it is pretty vague, the bottom line appears to be that peer-to-peer traffic (device-to-device traffic) is allowed. I'm fine with applying the patch. 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/