From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: Re: [PATCH 1/3] KVM: x86 emulator: Fix task switch privilege checks Date: Fri, 27 Jan 2012 15:17:02 +0100 Message-ID: <20120127141702.GO19255@amd.com> References: <1327335048-31925-2-git-send-email-kwolf@redhat.com> <20120124140316.GD19255@amd.com> <4F1EBCF1.9050808@redhat.com> <20120124141630.GD9571@redhat.com> <4F1EBF32.6020904@redhat.com> <20120124162350.GD538@redhat.com> <20120125160058.GG19255@amd.com> <4F229F7E.5030905@redhat.com> <20120127133456.GN19255@amd.com> <4F22ACC0.7020506@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: Gleb Natapov , , , , To: Kevin Wolf Return-path: Received: from db3ehsobe005.messaging.microsoft.com ([213.199.154.143]:40230 "EHLO DB3EHSOBE001.bigfish.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751517Ab2A0ORN (ORCPT ); Fri, 27 Jan 2012 09:17:13 -0500 Content-Disposition: inline In-Reply-To: <4F22ACC0.7020506@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Fri, Jan 27, 2012 at 02:55:12PM +0100, Kevin Wolf wrote: > Am 27.01.2012 14:34, schrieb Joerg Roedel: > > On Fri, Jan 27, 2012 at 01:58:38PM +0100, Kevin Wolf wrote: > >> Am 25.01.2012 17:00, schrieb Joerg Roedel: > > > >> I just retried. I use kvm-kmod and kvm.git with HEAD at ff92e9b5 plus > >> the tree patches of this series plus a printk to output exit_int_info in > >> task_switch_intercept(). I ran taskswitch2 from kvm-unittests and got > >> two failures and my VM86 unit test which hung when trying to return from > >> VM86. I also ran the kernel that made me aware of the issue initially. > >> All debug messages show exit_int_info = 0. > > > > Okay, you are testing on a K8 which has exactly this bug. As I just > > found out it is documented as erratum 701. The good news is that this > > only happens on K8 and Fam11h, any later AMD processor doesn't have this > > bug. > > Meh. Unless you give me a newer processor, this doesn't really help > me... Doesn't look like there's any way to get a workaround, is there? I > guess I'll have to hack it locally and possibly break other guests with > the hacked module. No, unfortunatly there is no workaround for this problem. How do you plan to hack around it? Joerg -- AMD Operating System Research Center Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach General Managers: Alberto Bozzo Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632