From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Graf Subject: Re: [PATCH] Activate Virtualization On Demand v3 Date: Wed, 05 Nov 2008 12:55:20 +0100 Message-ID: <491189A8.4040405@suse.de> References: <1225881664-16643-1-git-send-email-agraf@suse.de> <4911885B.3040703@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, kraxel@redhat.com, anthony@codemonkey.ws, Sander.Vanleeuwen@sun.com, zach@vmware.com, brogers@novell.com To: Avi Kivity Return-path: Received: from mx1.suse.de ([195.135.220.2]:38344 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755384AbYKELzX (ORCPT ); Wed, 5 Nov 2008 06:55:23 -0500 In-Reply-To: <4911885B.3040703@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Avi Kivity wrote: > 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. >> >> So using this, KVM can be easily autoloaded, while keeping other >> hypervisors usable. >> >> v2 adds returns to non-x86 hardware_enables and adds IA64 change >> v3 changes: >> - use spin_lock instead of atomics >> - put locking to new functions hardware_{en,dis}able_all that get >> called >> on VM creation/destruction >> - remove usage counter checks where not necessary >> - return -EINVAL for IA64 slot < 0 case >> >> > > Is this v3 with all the latest changes? it precedes some messages > where you say you'll change things by about 40 minutes. Yeah, my clock was off. Somehow I get host time drifts sometimes when using KVM and my NTP client wasn't running. But maybe it's just me doing something wrong. > In any case, I'll defer applying until Eduardo's kdump/reboot changes > go in, since they touch the same places, and Eduardo's changes are > much harder to test. I agree. Apart from that, do I get an ACK for it, so I can at least put it into our package and rest assured nothing obvious is wrong :-)? Alex