On Thu, Oct 10, 2024 at 04:06:13PM -0400, Steven Sistare wrote:
> vhost requires us to stop the vm early:
> qmp_migrate
> stop vm
> migration_call_notifiers MIG_EVENT_PRECOPY_CPR_SETUP
> vhost_cpr_notifier
> vhost_reset_device - must be after stop vm
> - and before new qemu inits devices
> cpr_state_save
> unblocks new qemu which inits devices and calls vhost_set_owner
>
> Thus config commands must be sent to the target during the guest pause
> interval :(
I can understand it needs VM stopped, but it can still happen after
cpr_save(), am I right (IOW, fd wont change in the notifier)? I meant
below sequence:
- src: cpr_save(), when running, NONE->SETUP_CPR, all fds synced
- [whatever happens..]
- src: finally decide to switchover, vm stop
- vhost notifier invoked. PS: it doesn't require to be named SETUP_CPR
notifiers here, but something else..
>
> My new proposal addresses this.
Yes, we can discuss that first.
--
Peter Xu
