From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 08/16] x86: Emergency virtualization disable function Date: Thu, 06 Nov 2008 12:30:51 +0200 Message-ID: <4912C75B.8050508@redhat.com> References: <1225810364-8990-1-git-send-email-ehabkost@redhat.com> <1225810364-8990-9-git-send-email-ehabkost@redhat.com> <20081105175235.GJ5247@blackpad> <4912BD67.8000704@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Andrew Morton , Eduardo Habkost , kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "Rafael J. Wysocki" , Haren Myneni , Simon Horman , Ingo Molnar , Andrey Borzenkov , mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Vivek Goyal To: "Eric W. Biederman" Return-path: 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 Eric W. Biederman wrote: > >> If you want to be extra simple and safe, remove kvm from the equation. Make the >> disabling code part of kdump/emergency_restart and only rely on the convention >> that cr3.vmxe == vmxon. >> > Convention? > There is a de-facto convention supported by at least vmware and kvm. If cr4.vmxe is 1, then we are in vmx operation. If cr4.vmxe is 0, then we are not in vmx operation. This allows us to determine whether we need to execute vmxoff without any APIs. -- error compiling committee.c: too many arguments to function