From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34523) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dJNk9-0007xo-G0 for qemu-devel@nongnu.org; Fri, 09 Jun 2017 13:30:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dJNk5-00069Z-HK for qemu-devel@nongnu.org; Fri, 09 Jun 2017 13:30:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46630) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dJNk5-00069A-8c for qemu-devel@nongnu.org; Fri, 09 Jun 2017 13:30:37 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0928581222 for ; Fri, 9 Jun 2017 17:30:36 +0000 (UTC) From: Juan Quintela In-Reply-To: <877f0lgsxu.fsf@dusky.pond.sub.org> (Markus Armbruster's message of "Fri, 09 Jun 2017 16:02:37 +0200") References: <1496980142-8986-1-git-send-email-peterx@redhat.com> <877f0lgsxu.fsf@dusky.pond.sub.org> Reply-To: quintela@redhat.com Date: Fri, 09 Jun 2017 19:30:32 +0200 Message-ID: <87lgp183wn.fsf@secure.mitica> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v2 0/6] migration: objectify MigrationState List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster Cc: Peter Xu , qemu-devel@nongnu.org, Laurent Vivier , "Dr . David Alan Gilbert" Markus Armbruster wrote: > Test compile gripes: > > hw/xen/xen-common.c: In function =E2=80=98xen_init=E2=80=99: > hw/xen/xen-common.c:147:5: warning: implicit declaration of function = =E2=80=98register_compat_prop=E2=80=99 [-Wimplicit-function-declaration] > register_compat_prop("migration", "store-global-state", "off"); > ^~~~~~~~~~~~~~~~~~~~ > hw/xen/xen-common.c:147:5: warning: nested extern declaration of =E2= =80=98register_compat_prop=E2=80=99 [-Wnested-externs] > > You might want to install Xen development packages to catch such issues > earlier. > > Test run: > > $ qemu-system-x86_64 -device migration,help > migration.skip-section-footer=3Dbool > migration.store-global-state=3Dbool > migration.only-migratable=3Dbool > migration.skip-configuration=3Dbool > > What would adding this device do? Parameters, capabilities, options for migration. This was what we discussed on irc. We want to have a way to control migration features that depend on versions. So we disable new features for old machine types (normal thing that we do). But right now, creating such a new feature requires creating a couple of functions to set/clear the feature, adding includes on the destination side, etc. This was supposed to be a global property (or a qemu_opt, or whatever). Just something that could be enabled/disabled easily on machine types, and if possible independently of machine types. This (for instance) would allow that store-global-state is disabled by defaulte for machine-2.9 (I forgot the exact name for the machine type), but I can enable it by hand. That is very handy for testing. So, I think that the question is, how/where can we set that kind of properties? At least for me, being able to *also* set migration capabilities/parameters with this mechanism on the command line would be very nice, for instance -global migration.xbzrle on or -global migration.max-speed 2G I don't care about what is the exact syntax, or where we hang them, i.e. a new device, a new list, somewhere that already exist. That is what we ask for advice. Thanks for the review and the suggestions. Later, Juan.