From mboxrd@z Thu Jan 1 00:00:00 1970 From: Borislav Petkov Subject: Re: [PATCH 0/8] x86/fpu: Remove CR0.TS support Date: Tue, 1 Nov 2016 00:48:55 +0100 Message-ID: <20161031234855.qu64eamohn35jdo4@pd.tnic> References: <1477953679.2230.7.camel@tiscali.nl> <20161031230431.ompl6s6k4fj3vcds@pd.tnic> <1477955448.2230.12.camel@tiscali.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Cc: Andy Lutomirski , x86@kernel.org, linux-kernel@vger.kernel.org, Rusty Russell , Paolo Bonzini , Rik van Riel , kvm list To: Paul Bolle Return-path: Content-Disposition: inline In-Reply-To: <1477955448.2230.12.camel@tiscali.nl> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Tue, Nov 01, 2016 at 12:10:48AM +0100, Paul Bolle wrote: > See https://lists.ozlabs.org/pipermail/lguest/2013-May/002001.html . > Nobody cared enough to fix it. I cared enough to figure it all out. But > I didn't understand much of the possible solutions that where suggested > three years ago. I'm guessing the simple fix would be this: --- diff --git a/drivers/lguest/Kconfig b/drivers/lguest/Kconfig index 169172d2ba05..9c08b3050bb7 100644 --- a/drivers/lguest/Kconfig +++ b/drivers/lguest/Kconfig @@ -1,6 +1,6 @@ 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 --- 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... -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply.