Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751742AbaF2OBJ (ORCPT ); Sun, 29 Jun 2014 10:01:09 -0400 Received: from mail.skyhub.de ([78.46.96.112]:57112 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750969AbaF2OBH (ORCPT ); Sun, 29 Jun 2014 10:01:07 -0400 Date: Sun, 29 Jun 2014 16:01:04 +0200 From: Borislav Petkov To: Gleb Natapov Cc: Jan Kiszka , Paolo Bonzini , lkml , Peter Zijlstra , Steven Rostedt , x86-ml , kvm@vger.kernel.org, =?utf-8?B?SsO2cmcgUsO2ZGVs?= Subject: Re: __schedule #DF splat Message-ID: <20140629140104.GB12528@pd.tnic> References: <20140629064626.GD18167@minantech.com> <53AFE2B3.5080300@web.de> <20140629102403.GE18167@minantech.com> <53AFEB16.5040608@web.de> <20140629105339.GF18167@minantech.com> <53AFF192.7020801@web.de> <20140629115143.GA4362@pd.tnic> <53B0050B.90104@web.de> <20140629131443.GA5199@pd.tnic> <20140629134247.GG18167@minantech.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20140629134247.GG18167@minantech.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jun 29, 2014 at 04:42:47PM +0300, Gleb Natapov wrote: > Please do so and let us know. Yep, just did. Reverting ae9fedc793 fixes the issue. > reinj:1 means that previous injection failed due to another #PF that > happened during the event injection itself This may happen if GDT or fist > instruction of a fault handler is not mapped by shadow pages, but here > it says that the new page fault is at the same address as the previous > one as if GDT is or #PF handler is mapped there. Strange. Especially > since #DF is injected successfully, so GDT should be fine. May be wrong > cpl makes svm crazy? Well, I'm not going to even pretend to know kvm to know *when* we're saving VMCB state but if we're saving the wrong CPL and then doing the pagetable walk, I can very well imagine if the walker gets confused. One possible issue could be U/S bit (bit 2) in the PTE bits which allows access to supervisor pages only when CPL < 3. I.e., CPL has effect on pagetable walk and a wrong CPL level could break it. All a conjecture though... -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/