From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:49712) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TDGWy-0000EX-3v for qemu-devel@nongnu.org; Sun, 16 Sep 2012 11:13:08 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TDGWx-00060M-4L for qemu-devel@nongnu.org; Sun, 16 Sep 2012 11:13:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38985) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TDGWw-00060H-Rx for qemu-devel@nongnu.org; Sun, 16 Sep 2012 11:13:07 -0400 Date: Sun, 16 Sep 2012 18:14:34 +0300 From: "Michael S. Tsirkin" Message-ID: <20120916151433.GA27428@redhat.com> References: <20120915181412.GA15606@redhat.com> <87k3vunhvq.fsf@codemonkey.ws> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87k3vunhvq.fsf@codemonkey.ws> Subject: Re: [Qemu-devel] [PATCH 11/25] q35: Introduce q35 pc based chipset emulator List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: alex.williamson@redhat.com, jan.kiszka@siemens.com, Jason Baron , qemu-devel@nongnu.org, agraf@suse.de, yamahata@valinux.co.jp, juzhang@redhat.com, kevin@koconnor.net, avi@redhat.com, mkletzan@redhat.com, lcapitulino@redhat.com, afaerber@suse.de, armbru@redhat.com On Sun, Sep 16, 2012 at 09:48:25AM -0500, Anthony Liguori wrote: > > I wonder if it's possible for q35 to have no devices > > at all in the default machine and have it > > fully qualified by -device switches? > > > > I envision -M qemu-1.3 switch that does exactly that, > > so that machine type only handles things like > > cross version compatibility. > > It's more than just "no devices". It's a matter of proper modeling of > the chipset, the super I/O chip, and peripherals. OK I guess the answer us no then. However, if you look at hw/pc_piix.c you see a bunch of version compatiblity code. Other systems do not have this I guess mostly because they worry less about compatibility ATM. Looks like if we start bothering about compatibility for both q35 and piix we'll have a lot of code duplication between the two. This problem is not limited to pc though, I expect it with time we'll have it for power and arm. I wonder what the solution is. Move compat code out of pc_piix, making it non pc specific? -- MST