From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:45485) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R4EAJ-0001a5-Is for qemu-devel@nongnu.org; Thu, 15 Sep 2011 11:47:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1R4EAF-0006Tg-El for qemu-devel@nongnu.org; Thu, 15 Sep 2011 11:47:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:23109) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1R4EAF-0006TE-4Z for qemu-devel@nongnu.org; Thu, 15 Sep 2011 11:47:47 -0400 Message-ID: <4E721E1C.20603@redhat.com> Date: Thu, 15 Sep 2011 17:47:40 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <4E70EC90.8000904@us.ibm.com> <4E719F7C.10700@redhat.com> <4E71FD19.6050606@codemonkey.ws> <4E71FF3E.9040008@redhat.com> <4E72093B.5060703@codemonkey.ws> <4E720CBD.2060806@redhat.com> <4E721A37.5020605@codemonkey.ws> In-Reply-To: <4E721A37.5020605@codemonkey.ws> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC] Plan for moving forward with QOM List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Peter Maydell , Jan Kiszka , qemu-devel , Markus Armbruster , Gerd Hoffmann , "Edgar E. Iglesias" On 09/15/2011 05:31 PM, Anthony Liguori wrote: >> >> I think it's in the eye of a beholder. Hold a PCI NE2000 and E1000, >> they're clearly both PciDevices, but also they clearly both have PciConnectors. >> >> Write a driver for a PCI and ISA NE2000, and then they're clearly both >> NE2000, but also they clearly both have an NE2K chip. > > Are we just bike shedding then? Since both models can be expressed by > the same infrastructure, does it really matter which model is the One > True Right Model? Well, it matters when "how do we model PCI" covers 90% of the devices around. :) In general, early conversions tend to become models for later ones. It's certainly good that QOM can be applied to either model. If it couldn't, something would be very wrong in it. > I think this might be a better discussion to have during conversions. > IOW, what makes sense for PCI, what makes sense for ISA, etc. More pragmatically, what I am suggesting is a refactoring of how PCI is abstracted, and that obviously makes it less appealing than a straight conversion. So, it would have been nice to have it as the one true right model, and as an example of how to do buses in QOM, but it is indeed safer to do it in two steps. Connectors can be done later when somebody will really need to inherit from something else. Paolo