From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756760AbZETMCi (ORCPT ); Wed, 20 May 2009 08:02:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754932AbZETMCa (ORCPT ); Wed, 20 May 2009 08:02:30 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:56445 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754771AbZETMC3 (ORCPT ); Wed, 20 May 2009 08:02:29 -0400 To: Joerg Roedel Cc: Ingo Molnar , Yinghai Lu , Weidong Han , dwmw2@infradead.org, suresh.b.siddha@intel.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, kvm@vger.kernel.org Subject: Re: [PATCH v2 2/2] Intel-IOMMU, intr-remap: source-id checking References: <1242757912-6041-1-git-send-email-weidong.han@intel.com> <1242757912-6041-3-git-send-email-weidong.han@intel.com> <20090519115055.GB14305@elte.hu> <20090520082114.GC6736@elte.hu> <20090520094310.GF9835@amd.com> From: ebiederm@xmission.com (Eric W. Biederman) Date: Wed, 20 May 2009 05:02:23 -0700 In-Reply-To: <20090520094310.GF9835@amd.com> (Joerg Roedel's message of "Wed\, 20 May 2009 11\:43\:10 +0200") Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-XM-SPF: eid=;;;mid=;;;hst=in02.mta.xmission.com;;;ip=76.21.114.89;;;frm=ebiederm@xmission.com;;;spf=neutral X-SA-Exim-Connect-IP: 76.21.114.89 X-SA-Exim-Rcpt-To: joerg.roedel@amd.com, kvm@vger.kernel.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, suresh.b.siddha@intel.com, dwmw2@infradead.org, weidong.han@intel.com, yinghai@kernel.org, mingo@elte.hu X-SA-Exim-Mail-From: ebiederm@xmission.com X-SA-Exim-Version: 4.2.1 (built Thu, 25 Oct 2007 00:26:12 +0000) X-SA-Exim-Scanned: No (on in02.mta.xmission.com); Unknown failure Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Joerg Roedel writes: > On Wed, May 20, 2009 at 10:21:14AM +0200, Ingo Molnar wrote: >> >> * Eric W. Biederman wrote: >> > Being a major nitpick, I have to point out that the code is not >> > structured to support other iommus, and I think AMD has one that >> > can do this as well. >> >> (Joerg Cc:-ed) > > The AMD IOMMU does also have an interrupt remapping feature. But it is > currently unsupported in the Linux driver. When this is going to be > implemented I think we can go the same way as for device passthrough in > KVM. This was an Intel-only feature too and was later adapted to support > AMD IOMMU too. The Intel IOMMU is also interesting because it allows traffic from buggy ioapcis to be remapped safely in process context, adding a large margin of safety and flexibility to the existing irq migration and cpu hotunplug scenarios. Can we use the AMD IOMMU to achieve the same objective? I would really like to say from point X on AMD and Intel systems don't have to worry about irq migrations used caused by old buggy ioapic state machines, which I have previously confirmed in both AMD and Intel ioapics. Eric