From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43179) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WDGdF-00073e-Jb for qemu-devel@nongnu.org; Tue, 11 Feb 2014 11:57:07 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WDGcZ-0004XO-GD for qemu-devel@nongnu.org; Tue, 11 Feb 2014 11:56:25 -0500 Received: from cantor2.suse.de ([195.135.220.15]:40269 helo=mx2.suse.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WDGcY-0004Ue-MX for qemu-devel@nongnu.org; Tue, 11 Feb 2014 11:55:43 -0500 Message-ID: <52FA5605.7040305@suse.de> Date: Tue, 11 Feb 2014 17:55:33 +0100 From: =?ISO-8859-1?Q?Andreas_F=E4rber?= MIME-Version: 1.0 References: <20140205154007.4886f3e3@thinkpad> <52F26363.2050607@suse.de> <20140205175216.3e011738@thinkpad> <20140206161901.14d44e55@nial.usersys.redhat.com> <52F3AF75.90106@suse.de> <20140206161627.GE28427@otherpad.lan.raisama.net> <52F3BF02.3070804@suse.de> <20140207101609.GF28427@otherpad.lan.raisama.net> <52F4BB9D.60301@redhat.com> <20140211152544.GA24353@otherpad.lan.raisama.net> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] CPU models and feature probing (was Re: [PATCH qom-cpu 00/16 v10] target-i386: convert CPU) features into properties List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori , Eduardo Habkost Cc: libvir-list@redhat.com, Markus Armbruster , qemu-devel , Anthony Liguori , Igor Mammedov , Paolo Bonzini , Jiri Denemark , Amos Kong Am 11.02.2014 16:58, schrieb Anthony Liguori: > On Tue, Feb 11, 2014 at 7:25 AM, Eduardo Habkost = wrote: >> On Tue, Feb 11, 2014 at 06:31:35AM -0800, Anthony Liguori wrote: >>> On Fri, Feb 7, 2014 at 2:55 AM, Paolo Bonzini w= rote: >>>> Il 07/02/2014 11:16, Eduardo Habkost ha scritto: >>>> >>>>> You are not alone. I remember we spent lots of time trying to convi= nce >>>>> Anthony to allow global properties and compat_props affect dynamic >>>>> properties not just static properties, and static properties were a= big >>>>> deal due to reasons I didn't understand completely. Now I am hearin= g the >>>>> opposite message, and I don't understand the reasons for the change= of >>>>> plans. I am confused. >>>> >>>> >>>> Picture me confused as well, but at the same I think I understand th= e >>>> reasons for the change of plans. >>> >>> There's no real convincing. It's just a question of code. >> >> I am sure there's a lot of convincing involved, even after the code is >> written (in this case, 15 months after the code was written). >=20 > N.B. the code you refer to doesn't "make global propeties and > compat_props affect dynamic properties." It converts CPU properties > to static properties which I'm pretty sure I said many times is a > perfectly reasonable thing to do. >=20 >>> There are >>> no defaults in classes for dynamic properties to modify. compat_prop= s >>> are a nice mechanism, making them work for all properties is a >>> reasonable thing to do. >> >> That's exactly the opposite of what you said before[1]. But that isn't >> supposed to be a problem, I understand there may be change of plans (w= e >> should be able to change our minds). >=20 > I think you're confusing a few things. You cannot make dynamic > properties work with globals today. Globals change class default > values and there are no class defaults for dynamic properties.[*] >=20 > There's a perfectly valid discussion to have about whether we should > even have dynamic properties. It's certainly been a long time since > they were introduced and they haven't made their way into all that > many devices so it's reasonable to say that perhaps we'd be better off > without them. I would not object to a patch series that moved > properties to classes entirely provided it removed existing uses of > dynamic properties and didn't just introduce yet another mechanism. >=20 > But compat properties as a concept could be made to work with dynamic > properties. They would have to be evaluated after instance init. > There's quite a few places they would end up touching I suspect. Erm, sorry, that is already implemented in qemu.git!? instance_post_init by Eduardo plus glue by me. Andreas >=20 > Another point of confusion worth mention is legacy properties since > this usually comes up in the discussion. Legacy properties (the > properties that are set/get as strings) are something that we should > try to avoid. They end up as strings on the wire and make it harder > to write client code. >=20 > * I recognize that compat_props are implemented as globals. I'm > really talking about the current implementation of globals, not the > concept of -global which could be made with dynamic properties. >=20 > Regards, >=20 > Anthony Liguori >=20 >> What I don't understand is the rejection of code that works, matches t= he >> style used by 200+ other source files, adds more useful introspectable >> information, done in the way that was suggested 16 months ago, because >> we have some rough idea about how a new grand design will look like in >> the far future. >> >> [1] http://lists.gnu.org/archive/html/qemu-devel/2013-06/msg00990.html >> >> -- >> Eduardo --=20 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg, Germany GF: Jeff Hawn, Jennifer Guild, Felix Imend=F6rffer; HRB 16746 AG N=FCrnbe= rg