Re: [libvirt] [PATCH 0/3] libxl: support Xen migration stream V2

Hi all, This patch adds support for Xen migration stream V2 to the libvirt libxl driver. In the process it fixes save/restore and migration tests in OSSTest, which have been failing since libvirt commit e7440656. Patch1 changes the libxl API requirement from version 4.2 to 4.4, enabling use of an extended libxl_domain_create_restore() function that allows passing restore parameters such as stream version. Patch2 adds support for migration stream V2 in the basic save/restore logic, taking advantage of a save image header that includes a version field. The version is set to '2' if the host produces a V2 migration stream. This patch fixes the failing save/restore tests in OSSTest. Patch3 adds support for migration stream V2 in the migration logic. The migration code does not use the save image header and instead uses libvirt's migration protocol to transfer domain configuration and other such goodies from source to destination. The patch enables sending version information in the Begin and Prepare migration phases so the correct stream version information can be passed to libxl_domain_create_restore(). An upshot of this approach is safely detecting and aborting a migration from a V2 host to a V1-only host. This patch fixes the failing migration tests in OSSTest.