Tested this series of patches with virtio-net regression tests, everything works fine.
Tested-by: Lei Yang <[email protected]> On Wed, Oct 15, 2025 at 9:21 PM Vladimir Sementsov-Ogievskiy <[email protected]> wrote: > > Hi all! > > Here is a new migration parameter backend-transfer, which, being > assisted by new device property backend-transfer, allows to > enable local migration of TAP virtio-net backend, including its > properties and open fds. > > With this new option, management software doesn't need to > initialize new TAP and do a switch to it. Nothing should be > done around virtio-net in local migration: it just migrates > and continues to use same TAP device. So we avoid extra logic > in management software, extra allocations in kernel (for new TAP), > and corresponding extra delay in migration downtime. > > v8: > 14: add a-b by Peter > 16: rework to one boolean parameter > 17: rework to use per-device property > 19: update to use new API > > Vladimir Sementsov-Ogievskiy (19): > net/tap: net_init_tap_one(): drop extra error propagation > net/tap: net_init_tap_one(): move parameter checking earlier > net/tap: rework net_tap_init() > net/tap: pass NULL to net_init_tap_one() in cases when scripts are > NULL > net/tap: rework scripts handling > net/tap: setup exit notifier only when needed > net/tap: split net_tap_fd_init() > net/tap: tap_set_sndbuf(): add return value > net/tap: rework tap_set_sndbuf() > net/tap: rework sndbuf handling > net/tap: introduce net_tap_setup() > net/tap: move vhost fd initialization to net_tap_new() > net/tap: finalize net_tap_set_fd() logic > migration: introduce .pre_incoming() vmsd handler > net/tap: postpone tap setup to pre-incoming > qapi: introduce backend-transfer migration parameter > virtio-net: support backend-transfer migration for virtio-net/tap > tests/functional: add skipWithoutSudo() decorator > tests/functional: add test_x86_64_tap_migration > > hw/core/machine.c | 1 + > hw/net/virtio-net.c | 151 ++++++- > include/hw/virtio/virtio-net.h | 1 + > include/migration/vmstate.h | 1 + > include/net/tap.h | 5 + > migration/migration.c | 4 + > migration/options.c | 18 + > migration/options.h | 2 + > migration/savevm.c | 15 + > migration/savevm.h | 1 + > net/tap-bsd.c | 3 +- > net/tap-linux.c | 19 +- > net/tap-solaris.c | 3 +- > net/tap-stub.c | 3 +- > net/tap-win32.c | 11 + > net/tap.c | 425 +++++++++++++----- > net/tap_int.h | 3 +- > qapi/migration.json | 38 +- > tests/functional/qemu_test/decorators.py | 16 + > tests/functional/test_x86_64_tap_migration.py | 395 ++++++++++++++++ > 20 files changed, 984 insertions(+), 131 deletions(-) > create mode 100644 tests/functional/test_x86_64_tap_migration.py > > -- > 2.48.1 >
