From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: KVM & VMX root mode Date: Sat, 01 Sep 2007 17:25:45 +0300 Message-ID: <46D97669.7050609@qumranet.com> References: <46D81156.8050100@innotek.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Sander van Leeuwen Return-path: In-Reply-To: <46D81156.8050100-2taLTamkYL2ELgA04lAiVw@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Sander van Leeuwen wrote: > Hi, > > We have had several reports of users saying our product VirtualBox > crashes their (Linux) host. It turned out that KVM is responsible, because > it leaves the CPU in VMX root mode. > > Doing this changes the way the cpu operates: updates to reserved bits in > control registers cause general protection faults. > We hit such cases on two occasions; clearing the X86_CR4_VMXE bit in CR4 > and turning off paging. > > I have added a workaround to detect VMX root mode, simply refuse to run > and recommend that the user disables KVM. > I would however appreciate if you could fix KVM instead. > > Simply '/sbin/rmmod kvm-intel' and kvm will exit vmx root mode. -- Any sufficiently difficult bug is indistinguishable from a feature. ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/