Re: [libvirt] [PATCH] RFC: Support QEMU live uprgade

Hi all, Recently QEMU developers are working on a feature to allow upgrading a live QEMU instance to a new version without restarting the VM. This is implemented as live migration between the old and new QEMU process on the same host [1]. Here is the the use case: 1) Guests are running QEMU release 1.6.1. 2) Admin installs QEMU release 1.6.2 via RPM or deb. 3) Admin starts a new VM using the updated QEMU binary, and asks the old QEMU process to migrate the VM to the newly started VM. I think it will be very useful to support QEMU live upgrade in libvirt. After some investigations, I found migrating to the same host breaks the current migration code. I'd like to propose a new work flow for QEMU live migration. It is to implement the above step 3).