From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:39941) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QHZ5b-0002yo-BK for qemu-devel@nongnu.org; Wed, 04 May 2011 06:13:52 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QHZ5Z-0003Zm-S6 for qemu-devel@nongnu.org; Wed, 04 May 2011 06:13:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:16481) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QHZ5Z-0003Zb-Fs for qemu-devel@nongnu.org; Wed, 04 May 2011 06:13:49 -0400 Date: Wed, 4 May 2011 11:13:28 +0100 From: "Daniel P. Berrange" Message-ID: <20110504101328.GC10300@redhat.com> References: <1304498343-9141-1-git-send-email-nick@bytemark.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1304498343-9141-1-git-send-email-nick@bytemark.co.uk> Subject: Re: [Qemu-devel] IPv6 support for TCP migrations Reply-To: "Daniel P. Berrange" List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: nick@bytemark.co.uk Cc: nick@lupine.me.uk, qemu-devel@nongnu.org On Wed, May 04, 2011 at 09:39:02AM +0100, nick@bytemark.co.uk wrote: > Hi, > > Currently migration-tcp.c uses the IPv4-only socket functions, making > migrations over IPv6 impossible. Following is a tentative patch that switches > it to use inet_connect() and inet_listen(). > > However, the patch loses the non-blocking connect() behaviour seen with the > previous code. I'm not sure how much of an issue this is - if connect() blocks > here, does it block execution of the VM? > > If so, I guess we need a non-blocking form of inet_connect(), or some way of > replicating the behaviour - it would potentially be needed for my NBD > reconnection patches too? I can see that a blocking connect() might not be an > issue while the KVM process is starting up, but could cause problems if we > try to reconnect while emulation is ongoing. > > Thoughts? FWIW, Juan Quintela also posted a set of patches to add IPv6 support for migration a few weeks back, but unfortunately they don't appear to have been merged yet: http://www.mail-archive.com/qemu-devel@nongnu.org/msg58954.html IIUC, Juan's patches don't have the blocking connect() problem you mention. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|