From mboxrd@z Thu Jan 1 00:00:00 1970 From: Muli Ben-Yehuda Subject: Re: iommu external module Date: Thu, 2 Oct 2008 17:58:45 +0300 Message-ID: <20081002145845.GB6909@il.ibm.com> References: <48E4C26D.6030608@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: KVM list To: Avi Kivity Return-path: Received: from mtagate1.de.ibm.com ([195.212.17.161]:53431 "EHLO mtagate1.de.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753368AbYJBO7Z (ORCPT ); Thu, 2 Oct 2008 10:59:25 -0400 Received: from d12nrmr1607.megacenter.de.ibm.com (d12nrmr1607.megacenter.de.ibm.com [9.149.167.49]) by mtagate1.de.ibm.com (8.13.1/8.13.1) with ESMTP id m92ExNap012029 for ; Thu, 2 Oct 2008 14:59:23 GMT Received: from d12av03.megacenter.de.ibm.com (d12av03.megacenter.de.ibm.com [9.149.165.213]) by d12nrmr1607.megacenter.de.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id m92ExN2N2003048 for ; Thu, 2 Oct 2008 16:59:23 +0200 Received: from d12av03.megacenter.de.ibm.com (loopback [127.0.0.1]) by d12av03.megacenter.de.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m92ExJpl022924 for ; Thu, 2 Oct 2008 16:59:19 +0200 Content-Disposition: inline In-Reply-To: <48E4C26D.6030608@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Thu, Oct 02, 2008 at 03:45:33PM +0300, Avi Kivity wrote: > We can fix this fairly simply by having an external module for the > iommus, much like kvm itself. I don't think it should be too > difficult, and it will provide a lot of testing to us, and important > functionality for our users. The problem is that if we want to enable DMA translation for a given device, we have to do it before it has any outstanding DMAs. As long as you have a device that you want to enable translation for as built-in, you'll need the IOMMU built-in as well, or will need to reset the device when you load the IOMMU. That's why all IOMMUs are currently built-in. Cheers, Muli -- The First Workshop on I/O Virtualization (WIOV '08) Dec 2008, San Diego, CA, http://www.usenix.org/wiov08/ <-> SYSTOR 2009---The Israeli Experimental Systems Conference http://www.haifa.il.ibm.com/conferences/systor2009/