From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755326Ab1KLAro (ORCPT ); Fri, 11 Nov 2011 19:47:44 -0500 Received: from sous-sol.org ([216.99.217.87]:57645 "EHLO sequoia.sous-sol.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754803Ab1KLArn (ORCPT ); Fri, 11 Nov 2011 19:47:43 -0500 Date: Fri, 11 Nov 2011 16:47:36 -0800 From: Chris Wright To: Chris Wright Cc: David Woodhouse , linux-pci@vger.kernel.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] intel-iommu: Default to non-coherent for domains unattached to iommus Message-ID: <20111112004736.GQ14486@sequoia.sous-sol.org> References: <20111111224849.9756.13368.stgit@bling.home> <1321058267.2006.21.camel@shinybook.infradead.org> <20111112004513.GP14486@sequoia.sous-sol.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20111112004513.GP14486@sequoia.sous-sol.org> User-Agent: Mutt/1.5.20 (2009-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Chris Wright (chrisw@sous-sol.org) wrote: > * David Woodhouse (dwmw2@infradead.org) wrote: > > So if you were to ditch the whole idea of a per-domain runtime update, > > and instead calculate a global value for 'iommu_coherency' at boot time, > > by iterating over for_each_active_iommu()¹, I think that would be a > > better way to deal with the issue. And you *could* really call that a > > 'fix'. > > > > Make sense? > > Ideally, yes. Not sure we can practically do it though. Would have to > be sure we force incoherent access mode for the busted hw. Forgot to mention, the simple patch may be the better choice for -stable (assuming the page table mapping issue...isn't).