From mboxrd@z Thu Jan 1 00:00:00 1970 From: bugzilla-daemon@bugzilla.kernel.org Subject: [Bug 81841] amd-iommu: kernel BUG & lockup after shutting down KVM guest using PCI passthrough/PCIe bridge Date: Fri, 08 Aug 2014 02:48:14 +0000 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit To: kvm@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.19.201]:55894 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755420AbaHHCsS (ORCPT ); Thu, 7 Aug 2014 22:48:18 -0400 Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 509E8201E4 for ; Fri, 8 Aug 2014 02:48:17 +0000 (UTC) Received: from bugzilla2.web.kernel.org (bugzilla2.web.kernel.org [172.20.200.52]) by mail.kernel.org (Postfix) with ESMTP id 1F5DE201B4 for ; Fri, 8 Aug 2014 02:48:15 +0000 (UTC) In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: https://bugzilla.kernel.org/show_bug.cgi?id=81841 Joel Schopp changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |joel.schopp@amd.com --- Comment #10 from Joel Schopp --- (In reply to Alex Williamson from comment #9) > (In reply to Marti Raudsepp from comment #8) > > (In reply to Alex Williamson from comment #7) > > > > There are some proposed workarounds on the web > > > None of these remotely address the issue. > > > > I see. This page claims so: http://www.ovirt.org/Features/hostdev_passthrough > > Sorry, it's wrong. > > > > there are quirks for the following AMD southbridge components > > > > Nope, mine are 1022:780b, 1022:780c, 1022:780d, 1022:780e, 1022:780f, > > 1022:7809 > > > > > If your bridge does not match these, then AMD will need to confirm whether > > > isolation is provided between your devices. > > > > How would I go about confirming that? What are the chances that they care, > > and provide accurate information to a random person? Are you suggesting we'd provide innacurate information to a random person? > > AMD would need to confirm it. IOMMU groups are based on hardware advertised > isolation via the PCIe ACS capability. Without this, or a device specific > quirk to take its place, IOMMU groups must assume that peer-to-peer between > functions of a multi-function device is possible and therefore that the > devices are not isolated. Chances are that this new chipset in your system > is taking the exact same ASICs that were deemed not to do peer-to-peer on > previous chipsets, but we need that confirmation from AMD. Alex Deucher > (see MAINTAINERS) may have contacts available that can make that statement. I don't have an answer for you offhand. Let me do some digging and get you an answer. > > > > There is an ACS override patch > > > > I already ran across it... > > https://bugzilla.redhat.com/show_bug.cgi?id=1113399 > > Would I be any worse off using this, compared to the old kvm pci-assign > > method? > > I think the path forward is to get confirmation from AMD that these function > are isolated from each other and add quirks to the kernel. Then you won't > have the device dependencies in vfio-pci. The override patch allows you to > do that with just a kernel boot parameter. There's no gurantee that > pci-assign will ever be fixed since it's being phased out. -- You are receiving this mail because: You are watching the assignee of the bug.