From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39451) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Wv1Xe-0001su-7M for qemu-devel@nongnu.org; Thu, 12 Jun 2014 05:43:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Wv1XY-00036q-25 for qemu-devel@nongnu.org; Thu, 12 Jun 2014 05:43:30 -0400 Received: from cantor2.suse.de ([195.135.220.15]:58546 helo=mx2.suse.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Wv1XX-00036g-RU for qemu-devel@nongnu.org; Thu, 12 Jun 2014 05:43:23 -0400 Message-ID: <53997638.6020403@suse.de> Date: Thu, 12 Jun 2014 11:43:20 +0200 From: Alexander Graf MIME-Version: 1.0 References: <20140514154130.10746.1412.stgit@bahia.local> <20140514154230.10746.56297.stgit@bahia.local> <5384A8D2.8050104@redhat.com> <20140529111253.4ff55199@bahia.local> <538708FA.4070309@redhat.com> <20140612094351.6295fd38@bahia.local> <53996B0E.4040808@redhat.com> <20140612110601.3fe5626e@bahia.local> <539970B3.3040304@redhat.com> <20140612093712.GA22565@redhat.com> <5399755E.10902@redhat.com> In-Reply-To: <5399755E.10902@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH RFC 8/8] virtio: add endian-ambivalent support to VirtIODevice List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini , "Michael S. Tsirkin" Cc: Kevin Wolf , Fam Zheng , Stefan Hajnoczi , Juan Quintela , qemu-devel@nongnu.org, Anthony Liguori , Amit Shah , =?ISO-8859-1?Q?Andreas_F=E4rber?= , Greg Kurz On 12.06.14 11:39, Paolo Bonzini wrote: > Il 12/06/2014 11:37, Michael S. Tsirkin ha scritto: >> Maybe just drop unnecessary stuff for new machine types? >> Then we won't need hacks to migrate it. > > For any machine type it's trivial to migrate it. All machine types > including old ones can disregard the migrated values. How about a patch like this before the actual LE awareness ones? With this we should make virtio-serial config space completely independent of live migration. Also since QEMU versions that do read these swapped values during migration are not bi-endian aware, we can never get into a case where a cross-endian save needs to be considered ;). Alex diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c index 2b647b6..73cb9b7 100644 --- a/hw/char/virtio-serial-bus.c +++ b/hw/char/virtio-serial-bus.c @@ -670,6 +670,7 @@ static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id) uint32_t max_nr_ports, nr_active_ports, ports_map; unsigned int i; int ret; + uint32_t tmp; if (version_id > 3) { return -EINVAL; @@ -685,17 +686,12 @@ static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id) return 0; } - /* The config space */ - qemu_get_be16s(f, &s->config.cols); - qemu_get_be16s(f, &s->config.rows); - - qemu_get_be32s(f, &max_nr_ports); - tswap32s(&max_nr_ports); - if (max_nr_ports > tswap32(s->config.max_nr_ports)) { - /* Source could have had more ports than us. Fail migration. */ - return -EINVAL; - } + /* Unused */ + qemu_get_be16s(f, &tmp); + qemu_get_be16s(f, &tmp); + qemu_get_be32s(f, &tmp); + max_nr_ports = tswap32(s->config.max_nr_ports); for (i = 0; i < (max_nr_ports + 31) / 32; i++) { qemu_get_be32s(f, &ports_map);