From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52340) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XA5YV-00026Q-UJ for qemu-devel@nongnu.org; Wed, 23 Jul 2014 19:02:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XA5YQ-00018Z-1o for qemu-devel@nongnu.org; Wed, 23 Jul 2014 19:02:39 -0400 Received: from cantor2.suse.de ([195.135.220.15]:41989 helo=mx2.suse.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XA5YP-00018A-Qm for qemu-devel@nongnu.org; Wed, 23 Jul 2014 19:02:33 -0400 Message-ID: <53D03F05.7000603@suse.de> Date: Thu, 24 Jul 2014 01:02:29 +0200 From: Alexander Graf MIME-Version: 1.0 References: <1404716892-15600-1-git-send-email-eric.auger@linaro.org> <1404716892-15600-6-git-send-email-eric.auger@linaro.org> <53BBF781.9070102@suse.de> <53CFD5D2.4090602@linaro.org> In-Reply-To: <53CFD5D2.4090602@linaro.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 5/7] hw/core/sysbus: add fdt_add_node method List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Auger , eric.auger@st.com, christoffer.dall@linaro.org, qemu-devel@nongnu.org, kim.phillips@freescale.com, a.rigo@virtualopensystems.com Cc: peter.maydell@linaro.org, patches@linaro.org, stuart.yoder@freescale.com, alex.williamson@redhat.com, a.motakis@virtualopensystems.com, kvmarm@lists.cs.columbia.edu On 23.07.14 17:33, Eric Auger wrote: > On 07/08/2014 03:52 PM, Alexander Graf wrote: >> On 07.07.14 09:08, Eric Auger wrote: >>> This method is meant to be called on sysbus device dynamic >>> instantiation (-device option). Devices that support this >>> kind of instantiation must implement this method. >>> >>> Signed-off-by: Eric Auger >> For the reason I stated earlier, I don't think it's a good idea to put >> device tree code into our device models. > Hi Alex, > > I would propose we discuss that topic during next KVM call if you are > available. I lost track when that would be. Next week would work fine, the week after not :). > Hope Peter will be available to join too. Because I feel > stuck between not putting things in the machine file (1) - obviously we > could put them in a helper module (2) - and not putting them in the > device (3). > > Whatever the solution I fear we are going to pollute something: Any time > a new device wants to support dynamic instantiation, we would need to > modify the machine file or the helper module with 1 and 2 resp. In case > we put it in the device we pollute this latter... > > My hope was that quite few QEMU platform devices would need to support > that feature and hence would need to implement this dt node generation > method. To me dynamic instantiation of platform device was not the > mainstream solution. Quite frankly I don't think it'd be that many. I think we'll cover 99.9% of all use cases if we just enable it for the virt machines of e500 and arm. > Then there is the fundamental question of technical feasibility of > devising a generic PlatformParams that match all the specialization > needs? Here I miss experience. In case we know the machine type and a > small set of additional fields couldn't we do the adaptations you talked > about, related to IRQs? The problem is that I don't know all the boards and different things people come up with either. There's also no reason machine files have to stick to the "platform bus" model - they could just take those devices and stick them into an existing other virtual bus. I don't feel comfortable generalizing something where I'm pretty sure things will blow up sooner or later. Alex