From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54359) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dKRyb-0008PU-Gj for qemu-devel@nongnu.org; Mon, 12 Jun 2017 12:14:02 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dKRyY-0005NQ-PG for qemu-devel@nongnu.org; Mon, 12 Jun 2017 12:14:01 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34044) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dKRyY-0005N8-G8 for qemu-devel@nongnu.org; Mon, 12 Jun 2017 12:13:58 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D2F9A285A8 for ; Mon, 12 Jun 2017 16:13:55 +0000 (UTC) Date: Mon, 12 Jun 2017 13:13:49 -0300 From: Eduardo Habkost Message-ID: <20170612161349.GL22043@thinpad.lan.raisama.net> References: <1496980142-8986-1-git-send-email-peterx@redhat.com> <1496980142-8986-3-git-send-email-peterx@redhat.com> <87lgp1i8kz.fsf@dusky.pond.sub.org> <20170612044609.GE25059@pxdev.xzpeter.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170612044609.GE25059@pxdev.xzpeter.org> Subject: Re: [Qemu-devel] [PATCH v2 2/6] migration: let MigrationState be a qdev List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Xu Cc: Markus Armbruster , Laurent Vivier , Juan Quintela , qemu-devel@nongnu.org, "Dr . David Alan Gilbert" On Mon, Jun 12, 2017 at 12:46:09PM +0800, Peter Xu wrote: > On Fri, Jun 09, 2017 at 03:39:24PM +0200, Markus Armbruster wrote: > > Peter Xu writes: > > > > > Let the old man "MigrationState" join the object family. Direct benefit > > > is that we can start to use all the property features derived from > > > current QDev, like: HW_COMPAT_* bits, command line setup for migration > > > parameters (so will never need to set them up each time using HMP/QMP, > > > this is really, really attractive for test writters), etc. > > > > > > I see no reason to disallow this happen yet. So let's start from this > > > one, to see whether it would be anything good. > > > > > > No functional change at all. > > > > > > Signed-off-by: Peter Xu > > > --- > > > include/migration/migration.h | 19 ++++++++++++++ > > > migration/migration.c | 61 ++++++++++++++++++++++++++++--------------- > > > 2 files changed, 59 insertions(+), 21 deletions(-) > > > > > > diff --git a/include/migration/migration.h b/include/migration/migration.h > > > index 79b5484..bd0186c 100644 > > > --- a/include/migration/migration.h > > > +++ b/include/migration/migration.h > > > @@ -21,6 +21,7 @@ > > > #include "qapi-types.h" > > > #include "exec/cpu-common.h" > > > #include "qemu/coroutine_int.h" > > > +#include "hw/qdev.h" > > > > > > #define QEMU_VM_FILE_MAGIC 0x5145564d > > > #define QEMU_VM_FILE_VERSION_COMPAT 0x00000002 > > > @@ -49,6 +50,8 @@ enum mig_rp_message_type { > > > MIG_RP_MSG_MAX > > > }; > > > > > > +#define TYPE_MIGRATION "migration" > > > + > > > /* State for the incoming migration */ > > > struct MigrationIncomingState { > > > QEMUFile *from_src_file; > > > @@ -91,8 +94,24 @@ struct MigrationIncomingState { > > > MigrationIncomingState *migration_incoming_get_current(void); > > > void migration_incoming_state_destroy(void); > > > > > > +#define MIGRATION_CLASS(klass) \ > > > + OBJECT_CLASS_CHECK(MigrationClass, (klass), TYPE_MIGRATION) > > > +#define MIGRATION_OBJ(obj) \ > > > + OBJECT_CHECK(MigrationState, (obj), TYPE_MIGRATION) > > > +#define MIGRATION_GET_CLASS(obj) \ > > > + OBJECT_GET_CLASS(MigrationClass, (obj), TYPE_MIGRATION) > > > + > > > +typedef struct MigrationClass { > > > + /*< private >*/ > > > + DeviceClass parent_class; > > > +} MigrationClass; > > > + > > > struct MigrationState > > > { > > > + /*< private >*/ > > > + DeviceState parent_obj; > > > + > > > + /*< public >*/ > > > > Turning MigrationState into a QOM object so you can use QOM > > infrastructure makes sense. But why turn it into a device? It doesn't > > feel device-like to me. Would ObjectClass and Object instead of > > DeviceClass and DeviceState do? > > Yeah. That's the main reason for the series to be (was) RFC. > > I was trying to use the HW_COMPAT_* bits and -global, and that's QDev > thing (IIUC you got that already :). I am just curious about why that > is not for QObject from the very beginning, then it'll be easier. > > For now, IMHO QDev is okay as well for migration, as long as it's kept > internally inside QEMU. But sure at least I should turn user_creatable > to off. I'll investigate more to see how to make this a safer approach > in next post. We could allow non-device QOM objects use the global property system optionally. We could make qdev_prop_set_globals() work on any Object*, and let QOM classes call it on post_init if they want to be configurable by global properties too. Note that this would break qdev_prop_check_globals(), because it expects globals to work only on TYPE_DEVICE. We could address that by introducing a new interface type to indicate the type works with -global (something like INTERFACE_CONFIGURABLE_BY_GLOBAL_PROPERTIES, but shorter?). Such a system would probably allow us to replace default_machine_opts, default_boot_order, default_display, default_ram_size (and probably many other compat fields) on MachineClass. It could also be used to implement -machine and -accel options by simply translating them to global properties (like we already do for -cpu). (This sounds like reinventing a QemuOpts-like system on top of global properties. Maybe that's a bad thing, maybe that's a good thing. I'm not sure.) > [...] -- Eduardo