Tap and vhost devices can be preserved during cpr-transfer using traditional live migration methods, wherein the management layer creates new interfaces for the target and fiddles with 'ip link' to deactivate the old interface and activate the new.
However, CPR can simply send the file descriptors to new QEMU, with no special management actions required. The user enables this behavior by specifing '-netdev tap,cpr=on'. The default is cpr=off. Steve Sistare (8): migration: stop vm earlier for cpr migration: cpr setup notifier vhost: reset vhost devices for cpr cpr: delete all fds Revert "vhost-backend: remove vhost_kernel_reset_device()" tap: common return label tap: cpr support tap: postload fix for cpr qapi/net.json | 5 +- include/hw/virtio/vhost.h | 1 + include/migration/cpr.h | 3 +- include/net/tap.h | 1 + hw/net/virtio-net.c | 20 +++++++ hw/vfio/device.c | 2 +- hw/virtio/vhost-backend.c | 6 ++ hw/virtio/vhost.c | 32 +++++++++++ migration/cpr.c | 24 ++++++-- migration/migration.c | 38 ++++++++----- net/tap-win32.c | 5 ++ net/tap.c | 141 +++++++++++++++++++++++++++++++++++----------- 12 files changed, 223 insertions(+), 55 deletions(-) -- 1.8.3.1
