From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] Activate Virtualization On Demand Date: Mon, 14 Sep 2009 08:05:32 +0300 Message-ID: <4AADCF1C.80505@redhat.com> References: <1252505938-3944-1-git-send-email-agraf@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, Marcelo Tosatti To: Alexander Graf Return-path: Received: from mx1.redhat.com ([209.132.183.28]:19063 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750739AbZINFFh (ORCPT ); Mon, 14 Sep 2009 01:05:37 -0400 In-Reply-To: <1252505938-3944-1-git-send-email-agraf@suse.de> Sender: kvm-owner@vger.kernel.org List-ID: On 09/09/2009 05:18 PM, Alexander Graf wrote: > X86 CPUs need to have some magic happening to enable the virtualization > extensions on them. This magic can result in unpleasant results for > users, like blocking other VMMs from working (vmx) or using invalid TLB > entries (svm). > > Currently KVM activates virtualization when the respective kernel module > is loaded. This blocks us from autoloading KVM modules without breaking > other VMMs. > > To circumvent this problem at least a bit, this patch introduces on > demand activation of virtualization. This means, that instead > virtualization is enabled on creation of the first virtual machine > and disabled on destruction of the last one. > > So using this, KVM can be easily autoloaded, while keeping other > hypervisors usable. > Looks good. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.