On Tue, Sep 23, 2025 at 01:01:05PM +0300, Vladimir Sementsov-Ogievskiy wrote: > We are going to implement backend-transfer migration feature for > virtio-net/tap. When it's enabled (by setting migration parameter), TAP > device is passed through migration channel (which should be a unix > socket to pass fds) to a new QEMU. > > So we need to know during TAP initialization, should we open TAP > device, or wait for incoming fds. But we can't check for migration > parameter at TAP creation time, as use may set migration parameter > later (especially when TAP is added by command line parameter). > > To solve this, we have prepared TAP initialization code so that > opening the device may be postponed to later point. And this later > point is obviously the early beginning of qmp_migrate_incoming(): > here we already know all migration parameters and capabilities, > but we are not in downtime, so we can continue initialization > of TAP device. > > This commit introduces MIG_EVENT_PRE_INCOMING, to be used by TAP > code in following commit. > > Signed-off-by: Vladimir Sementsov-Ogievskiy <[email protected]>
Acked-by: Peter Xu <[email protected]> -- Peter Xu
