From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:37624) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RczwX-0002gD-1l for qemu-devel@nongnu.org; Tue, 20 Dec 2011 08:41:25 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RczwR-0006cr-60 for qemu-devel@nongnu.org; Tue, 20 Dec 2011 08:41:21 -0500 Received: from mail-yw0-f45.google.com ([209.85.213.45]:42594) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RczwR-0006cj-3Z for qemu-devel@nongnu.org; Tue, 20 Dec 2011 08:41:15 -0500 Received: by yhgg71 with SMTP id g71so5417802yhg.4 for ; Tue, 20 Dec 2011 05:41:14 -0800 (PST) Message-ID: <4EF09078.2030508@codemonkey.ws> Date: Tue, 20 Dec 2011 07:41:12 -0600 From: Anthony Liguori MIME-Version: 1.0 References: <4EEFB72E.7030508@codemonkey.ws> <4EEFC970.9030205@web.de> <4EEFD69F.6080700@codemonkey.ws> <4EEFD786.8030609@web.de> <4EEFD90A.1000204@codemonkey.ws> <4EF05BC4.8010905@redhat.com> In-Reply-To: <4EF05BC4.8010905@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v5 06/16] apic: Introduce backend/frontend infrastructure for KVM reuse List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: Anthony Liguori , kvm@vger.kernel.org, "Michael S. Tsirkin" , Marcelo Tosatti , qemu-devel , Blue Swirl , Jan Kiszka On 12/20/2011 03:56 AM, Avi Kivity wrote: > On 12/20/2011 02:38 AM, Anthony Liguori wrote: >>> That was v1 of my patches. Avi didn't like it, I tried it like this, and >>> in the end I had to agree. So, no, I don't think we want such a model. >> >> >> Yes, we do :-) >> >> The in-kernel APIC is a different implementation of the APIC device. >> It's not an "accelerator" for the userspace APIC. > > A different implementation but not a different device. Device == spec. If it was hardware, it'd be a fully compatible clone. The way we would model this is via inheritance. Regards, Anthony Liguori > >> >> All that you're doing here is reinventing qdev. You're defining your >> own type system (APICBackend), creating a new regression system for >> it, and then defining your own factory function for creating it >> (through a qdev property). >> >> I'm struggling to understand the reason to avoid using the >> infrastructure we already have to do all of this. > > Not every table of function pointers has to be done through qdev (not > that I feel strongly about this - only that there is just one APIC device). >