From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1167903AbcKAHwG (ORCPT ); Tue, 1 Nov 2016 03:52:06 -0400 Received: from lb2-smtp-cloud6.xs4all.net ([194.109.24.28]:37083 "EHLO lb2-smtp-cloud6.xs4all.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1167786AbcKAHwD (ORCPT ); Tue, 1 Nov 2016 03:52:03 -0400 Message-ID: <1477986717.2230.25.camel@tiscali.nl> Subject: Re: [PATCH 0/8] x86/fpu: Remove CR0.TS support From: Paul Bolle To: Borislav Petkov Cc: Andy Lutomirski , x86@kernel.org, linux-kernel@vger.kernel.org, Rusty Russell , Paolo Bonzini , Rik van Riel , kvm list Date: Tue, 01 Nov 2016 08:51:57 +0100 In-Reply-To: <20161031234855.qu64eamohn35jdo4@pd.tnic> References: <1477953679.2230.7.camel@tiscali.nl> <20161031230431.ompl6s6k4fj3vcds@pd.tnic> <1477955448.2230.12.camel@tiscali.nl> <20161031234855.qu64eamohn35jdo4@pd.tnic> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.5 (3.20.5-1.fc24) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2016-11-01 at 00:48 +0100, Borislav Petkov wrote: > --- a/drivers/lguest/Kconfig > +++ b/drivers/lguest/Kconfig >  config LGUEST >   tristate "Linux hypervisor example code" > - depends on X86_32 && EVENTFD && TTY && PCI_DIRECT > > + depends on X86_32 && EVENTFD && TTY && PCI_DIRECT && !MICROCODE >   select HVC_DRIVER >   ---help--- >     This is a very simple module which allows you to run LGUEST is the symbol for host support. The symbol for guest support is LGUEST_GUEST and it lives in arch/x86/. Yes, it's a bit of a gotcha. > but maybe the better fix is to hack in MSR emulation in lguest and > intercept the *MSR accesses and do the writes/reads in the exception > fixup and ... > > I haven't looked at the lguest code, of course and whether that's easily > doable and whether it even makes sense and whether one should simply use > qemu/kvm instead and, and, and... Yeah, I thought about adding negative dependencies (eg, "!OLPC && !MICROCODE") too. But that would be contrary to the neat lguest goal to be able to use the same kernel image as a host and a guest. At least, I think that is one of its goals. And as probably everybody capable of hacking on lguest (ie, other people than me) came up with doubts similar to yours, these two issues never got fixed.    Thanks, Paul Bolle