From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [Qemu-devel] Re: [PATCH v2 4/9] provide in-kernel apic Date: Mon, 12 Oct 2009 08:41:20 -0500 Message-ID: <4AD33200.5060007@us.ibm.com> References: <1254953315-5761-1-git-send-email-glommer@redhat.com> <1254953315-5761-2-git-send-email-glommer@redhat.com> <1254953315-5761-3-git-send-email-glommer@redhat.com> <1254953315-5761-4-git-send-email-glommer@redhat.com> <1254953315-5761-5-git-send-email-glommer@redhat.com> <4ACDEF42.6020706@us.ibm.com> <4ACDF297.9010303@redhat.com> <20091008142202.GR8092@mothafucka.localdomain> <20091009100641.GC6576@shareable.org> <20091009143031.GU8092@mothafucka.localdomain> <20091009164831.GB7393@shareable.org> <4ACF93D5.3010002@us.ibm.com> <4AD1A112.4070303@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Jamie Lokier , Glauber Costa , qemu-devel@nongnu.org, kvm-devel To: Avi Kivity Return-path: Received: from e34.co.us.ibm.com ([32.97.110.152]:58007 "EHLO e34.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756582AbZJLNmW (ORCPT ); Mon, 12 Oct 2009 09:42:22 -0400 Received: from d03relay04.boulder.ibm.com (d03relay04.boulder.ibm.com [9.17.195.106]) by e34.co.us.ibm.com (8.14.3/8.13.1) with ESMTP id n9CDb2rT006960 for ; Mon, 12 Oct 2009 07:37:02 -0600 Received: from d03av03.boulder.ibm.com (d03av03.boulder.ibm.com [9.17.195.169]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id n9CDfLId183066 for ; Mon, 12 Oct 2009 07:41:22 -0600 Received: from d03av03.boulder.ibm.com (loopback [127.0.0.1]) by d03av03.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n9CDfLBk025567 for ; Mon, 12 Oct 2009 07:41:21 -0600 In-Reply-To: <4AD1A112.4070303@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Avi Kivity wrote: > On 10/09/2009 09:49 PM, Anthony Liguori wrote: >>> If I've just been sent an image produced by someone running KVM, and >>> my machine is not KVM-capable, or I cannot upgrade the KVM kernel >>> module because it's in use by other VMs (had this problem a few >>> times), there's no choice but to change the irqchipness. >> >> >> You cannot migrate from KVM to TCG so this use-case is irrelevant. > > I agree it's mostly irrelevant, however nothing in principle prevents > such a migration, as long as the cpuid feature bits are implemented on > both sides. Sure, in principle it's certainly possible but in practice, it isn't today and I don't see anything that's likely to happen in the near term future that would make it. -- Regards, Anthony Liguori