From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262028AbUBWWD1 (ORCPT ); Mon, 23 Feb 2004 17:03:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262056AbUBWWD1 (ORCPT ); Mon, 23 Feb 2004 17:03:27 -0500 Received: from fw.osdl.org ([65.172.181.6]:49801 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S262028AbUBWWDZ (ORCPT ); Mon, 23 Feb 2004 17:03:25 -0500 Date: Mon, 23 Feb 2004 14:08:40 -0800 (PST) From: Linus Torvalds To: "David S. Miller" cc: riel@redhat.com, herbert@13thfloor.at, mikpe@csd.uu.se, linux-kernel@vger.kernel.org Subject: Re: Intel vs AMD x86-64 In-Reply-To: <20040223134853.5947a414.davem@redhat.com> Message-ID: References: <20040223134853.5947a414.davem@redhat.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 23 Feb 2004, David S. Miller wrote: > > You mean the PCI controller is in the CPU, else how else would you > accomplish this? The IOMMU basically needs to be on the northbridge or at least in between the PCI bus an a northbridge (pretty much by definition: the bridge between IO and memory). On an Opteron, that's on-the-chip. For current Intel chips that's a separate chip. In fact, I _think_ you could actually use the AGP bridge as a strange IOMMU. Of course, right now their AGP bridges are all 32-bit limited anyway, but the point being that they at least in theory would seem to have the capability to do this. > Really, not having an IOMMU on a 64-bit platform these days is basically like > pulling out one's toenails with an ice pick. Well, as long as they had that "64-bit is server" mentality, they can honestly say that you just have to use 64-bit-capable PCI cards. Now, the "server only" mentality is obviously crap, but since we haven't even seen the chipsets designed for the 64-bit chips, we shouldn't complain. At least yet. Now, I'm not above complaining about Intel (in fact, the Intel people seem to often think I hate them because I'm apparently the only person who gets quoted who complains about bad decisions publicly), but at least I try to avoid complaining before-the-fact ;) Linus