From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Daniel P. Berrange" Subject: Re: [PATCH] Activate Virtualization On Demand v2 Date: Wed, 5 Nov 2008 10:58:12 +0000 Message-ID: <20081105105812.GC25523@redhat.com> References: <1225874896-13186-1-git-send-email-agraf@suse.de> Reply-To: "Daniel P. Berrange" Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org, avi@redhat.com, kraxel@redhat.com, anthony@codemonkey.ws, Sander.Vanleeuwen@sun.com, zach@vmware.com, brogers@novell.com To: Alexander Graf Return-path: Received: from mx1.redhat.com ([66.187.233.31]:46237 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754704AbYKEK6n (ORCPT ); Wed, 5 Nov 2008 05:58:43 -0500 Content-Disposition: inline In-Reply-To: <1225874896-13186-1-git-send-email-agraf@suse.de> Sender: kvm-owner@vger.kernel.org List-ID: On Wed, Nov 05, 2008 at 09:48:16AM +0100, 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 removal of the last one. Pardon my unfamiliarity with the code, but with this change applied, will we still get an explicit error at time of loading kvm-intel.ko if VMX were disabled in the BIOS ? Or will that error reporting be pushed off to time when VMX is first activated ? Daniel -- |: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|