From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yosuke Iwamatsu Subject: Re: question on PV pass-through patch Date: Mon, 17 Mar 2008 11:31:57 +0900 Message-ID: <47DDD81D.50008@ab.jp.nec.com> References: <78C9135A3D2ECE4B8162EBDCE82CAD77032C0E38@nekter> <47D490BB.1020903@ab.jp.nec.com> <78C9135A3D2ECE4B8162EBDCE82CAD7703337835@nekter> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <78C9135A3D2ECE4B8162EBDCE82CAD7703337835@nekter> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Masroor Vettuparambil Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org Masroor Vettuparambil wrote: > > I tried your patch with CONFIG_XEN_PCIDEV_BACKEND_VPCI. > Detached the pci on the source and attached another slot to migrated > domU on destination. > Migration is happening smoothly. thanks for your work. > > a minor thing I noticed is, dmesg on domU shows the following warning > during pci-detach, > WARNING: g.e. still in use! > WARNING: leaking g.e. and page still in use! I'm not sure what this means, but it looks like something is wrong with the disconnect procedure of pcifront/pciback. > I wonder if we can achieve a 'live' migration of direct access, ie, > without interrupting the network traffic? > Something like creating a vif(network-attach) on domU for carrying the > n/w traffic temporarily till the migration is over. > After migration, move the n/w traffic back from vif to newly > pci-attached NIC on the destination. > Any thought? Actually I've been thinking of "passthrough domain live migration" using a multipath-driver which combines a passthrough device and a virtual device. Below is an idea of live migrating a domU which has passthrough network device attached. - First create bond0 and add the passthrough interface to it. - Usually we use the passthrough interface (fast path). - Before migration, attach a vif to the domU and add the vif interface to bond0. Then remove the passthrough inteface from bond0 and do pci-detach. We can migrate without network disconnection because the vif is now enabled (slow path). - After migration, do pci-attach, add passthrough interface to bond0, and disconnect the vif interface (switch back to fast path). I hope this method works, but I haven't have an opportunity to try it myself yet. Thanks, ------------------- Yosuke Iwamatsu NEC Corporation