Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932190AbZJ0IPe (ORCPT ); Tue, 27 Oct 2009 04:15:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932178AbZJ0IPa (ORCPT ); Tue, 27 Oct 2009 04:15:30 -0400 Received: from casper.infradead.org ([85.118.1.10]:59714 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932179AbZJ0IPY (ORCPT ); Tue, 27 Oct 2009 04:15:24 -0400 Subject: Re: [PATCH 4/5] intel-iommu: Reinstate RMRRs if a device is removed from passthrough domain From: David Woodhouse To: Alex Williamson Cc: iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org In-Reply-To: <20091026232514.9646.58322.stgit@nehalem.aw> References: <20091026232401.9646.90540.stgit@nehalem.aw> <20091026232514.9646.58322.stgit@nehalem.aw> Content-Type: text/plain; charset="UTF-8" Date: Tue, 27 Oct 2009 08:15:24 +0000 Message-Id: <1256631324.9814.14.camel@macbook.infradead.org> Mime-Version: 1.0 X-Mailer: Evolution 2.28.0 (2.28.0-2.fc12) 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 Content-Length: 1056 Lines: 24 On Mon, 2009-10-26 at 17:25 -0600, Alex Williamson wrote: > When a device is setup for passthrough it has full access to memory > so processing the RMRRs is unnecessary. However, if we remove the device > from the si_domain, we need to reinstate the associated RMRRs. > > Signed-off-by: Alex Williamson If your device is doing DMA to host memory autonomously, you may still have problems with this patch -- you take it out of the si_domain and then there's a period of time before you reapply the RMRRs, during which its DMA may be prevented. You want to set up the new domain first, then switch the device over to it atomically. -- David Woodhouse Open Source Technology Centre David.Woodhouse@intel.com Intel Corporation -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/