From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [Qemu-devel] Re: [PATCH v2 3/9] provide in-kernel ioapic Date: Thu, 08 Oct 2009 11:12:21 -0500 Message-ID: <4ACE0F65.6050906@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> <4ACDEDEC.60706@us.ibm.com> <4ACDEF03.6010406@redhat.com> <20091008160726.GD29691@shareable.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Avi Kivity , Glauber Costa , qemu-devel@nongnu.org, kvm-devel To: Jamie Lokier Return-path: Received: from e1.ny.us.ibm.com ([32.97.182.141]:55051 "EHLO e1.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932435AbZJHQNB (ORCPT ); Thu, 8 Oct 2009 12:13:01 -0400 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e1.ny.us.ibm.com (8.14.3/8.13.1) with ESMTP id n98GBCUl025942 for ; Thu, 8 Oct 2009 12:11:12 -0400 Received: from d01av01.pok.ibm.com (d01av01.pok.ibm.com [9.56.224.215]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id n98GCOBT248600 for ; Thu, 8 Oct 2009 12:12:24 -0400 Received: from d01av01.pok.ibm.com (loopback [127.0.0.1]) by d01av01.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n98GCNWG025387 for ; Thu, 8 Oct 2009 12:12:24 -0400 In-Reply-To: <20091008160726.GD29691@shareable.org> Sender: kvm-owner@vger.kernel.org List-ID: Jamie Lokier wrote: > Avi Kivity wrote: > >> On 10/08/2009 03:49 PM, Anthony Liguori wrote: >> >>> Glauber Costa wrote: >>> >>>> This patch provides kvm with an in-kernel ioapic. We are currently >>>> not enabling it. >>>> The code is heavily based on what's in qemu-kvm.git. >>>> >>> It really ought to be it's own file and own device model. Having the >>> code mixed in with ioapic.c is confusing because it's unclear what >>> code is in use when the in-kernel model is used. >>> >> I disagree. It's the same device with the same guest-visible interface >> and the same host-visible interface (save/restore, 'info ioapic' if we >> write one). Splitting it into two files will only result in code >> duplication. >> >> Think of it as an ioapic accelerator. >> > > Haven't we already confirmed that it *isn't* just an ioapic accelerator > because you can't migrate between in-kernel iopic and qemu's ioapic? > > Imho, if they cannot be swapped transparently, they are different > device emulations. > > OF course there's nothing wrong with sharing lots of code. > If you avoid having a common save format, you get an overall reduction in code size and there's virtually no code to share. -- Regards, Anthony Liguori