From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eduardo Habkost Subject: Re: [PATCH 0/2] kvm: disable virtualization on kdump Date: Mon, 27 Oct 2008 13:50:03 -0200 Message-ID: <20081027155003.GM23893@blackpad> References: <20081023194129.GD27959@blackpad> <20081023222906.GB10753@verge.net.au> <4904676F.3020706@redhat.com> <490487C1.1010707@redhat.com> <20081026213927.GF23893@blackpad> <49058645.9010005@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Andrew Morton , kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Haren Myneni , Simon Horman , Avi Kivity , Vivek Goyal To: "Eric W. Biederman" Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kexec-bounces-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org Errors-To: kexec-bounces+glkk-kexec=m.gmane.org-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: kvm.vger.kernel.org On Mon, Oct 27, 2008 at 08:05:50AM -0700, Eric W. Biederman wrote: > Avi Kivity writes: > > > There's no way to query whether vmx is enabled or disabled, AFAICT. So we have > > to execute vmxoff and ignore possible #UDs. > > > > If we trust the exception handlers, there's no problem. Otherwise we need to > > replace the current #UD handler with an iret (perhaps switching temporarily to > > another IDT). > > Ugh. We already change the IDT on that code path so that > may be a way to go. I don't see the IDT being changed on native_machine_shutdown(). It even uses notifier chain registration (register_die_notifier()) to sneak a NMI handler in. -- Eduardo