From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kashyap Chamarthy Subject: Re: nVMX regression v3.13+, bisected Date: Thu, 27 Feb 2014 02:14:23 +0530 Message-ID: <20140226204423.GA25995@tesla.redhat.com> References: <530E43EC.7000600@canonical.com> <530E4DB9.5050001@redhat.com> <530E4E25.4050508@canonical.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Paolo Bonzini , kvm@vger.kernel.org, Anthoine Bourgeois To: Stefan Bader Return-path: Received: from mx1.redhat.com ([209.132.183.28]:50763 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751159AbaBZUoj (ORCPT ); Wed, 26 Feb 2014 15:44:39 -0500 Content-Disposition: inline In-Reply-To: <530E4E25.4050508@canonical.com> Sender: kvm-owner@vger.kernel.org List-ID: On Wed, Feb 26, 2014 at 09:27:17PM +0100, Stefan Bader wrote: > On 26.02.2014 21:25, Paolo Bonzini wrote: [. . .] > >> > >> I bisected this and ended up on the following commit which, when reverted made > >> the launch work again: > >> > >> Author: Anthoine Bourgeois > >> Date: Wed Nov 13 11:45:37 2013 +0100 > >> > >> kvm, vmx: Fix lazy FPU on nested guest > >> > >> If a nested guest does a NM fault but its CR0 doesn't contain the TS > >> flag (because it was already cleared by the guest with L1 aid) then we > >> have to activate FPU ourselves in L0 and then continue to L2. If TS flag > >> is set then we fallback on the previous behavior, forward the fault to > >> L1 if it asked for. > >> > >> Signed-off-by: Anthoine Bourgeois > >> Signed-off-by: Paolo Bonzini > >> > >> The condition to exit to L0 seems to be according to what the description says. > >> Could it be that the handling in L0 is doing something wrong? > > > > Thanks, I'll look at it tomorrow or Friday. > > > > Paolo > > > Great thanks. And maybe it helps if I actually add the link to the bug report as > I had intended... :-P > > [1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1278531 Yes, I'm seeing something similar[*] in a consistent manner with minimal Fedora installs on L0, L1 and L2, but couldn't manage time to do the bisecting. I thought this would be my first bisecting exercise, but you already beat me to it. [*] https://bugzilla.kernel.org/show_bug.cgi?id=69491#c7 -- /kashyap