From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752647AbZIGMye (ORCPT ); Mon, 7 Sep 2009 08:54:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752294AbZIGMyd (ORCPT ); Mon, 7 Sep 2009 08:54:33 -0400 Received: from casper.infradead.org ([85.118.1.10]:51591 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752272AbZIGMyd (ORCPT ); Mon, 7 Sep 2009 08:54:33 -0400 Subject: Re: [PATCH 0/8] Passthrough support for AMD-IOMMU (AMD-Vi) From: David Woodhouse To: Joerg Roedel Cc: iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org In-Reply-To: <1252056994-31980-1-git-send-email-joerg.roedel@amd.com> References: <1252056994-31980-1-git-send-email-joerg.roedel@amd.com> Content-Type: text/plain Date: Mon, 07 Sep 2009 13:54:30 +0100 Message-Id: <1252328070.4483.569.camel@macbook.infradead.org> Mime-Version: 1.0 X-Mailer: Evolution 2.26.3 (2.26.3-1.fc11) Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2009-09-04 at 11:36 +0200, Joerg Roedel wrote: > > this series of patches implement iommu=pt support for AMD IOMMU (AMD-Vi). If > this option is passed on the kernel command line, the AMD-Vi driver will not > register itself as the dma_ops backend and allows all devices unlimited access > to main memory as long as no other kernel part (currently only KVM will do so) > assigns the device to another domain using the IOMMU-API. The Intel IOMMU used to behave like that in passthrough mode, but I've now changed it. Now, it will still register itself as the dma_ops backend, and it won't actually bypass the IOMMU for devices with a limited dma_mask. So you don't end up having to use swiotlb for those (which wasn't working anyway, iirc). The devices for which you actually care about performance are still going to end up with the passthrough mapping as you desire, anyway. -- David Woodhouse Open Source Technology Centre David.Woodhouse@intel.com Intel Corporation