Re: [PATCH] hw/intc/xics: Add missing call to register vmstate_icp_server

[Fabiano Rosas <farosas@suse.de>]

Fabian Vogt <fvogt@suse.de> writes:

+CC Peter

> An obsolete wrapper function with a workaround was removed entirely,
> without restoring the call it wrapped.
>
> Without this, the guest is stuck after savevm/loadvm.
>

I'd note that this only affects guests that have actually negotiated
XICS, so guests using ic-mode=xive are safe.

With this patch, backward migration to QEMU versions >= 9.2 is
broken. Which I can only assume is ok, since the hard break (vmstate
gets rejected) is better than weird post-migration hangs.

If the PPC folks can spot a scenario where migration would provide
reasonable results even without the emulated interrupt controller state
being migrated, then we'll need a compat property for this.

Also, a 9.2 guest cannot move to a more recent QEMU version without a
reboot. If this is an important scenario, then the new QEMU needs to
provide some compatibility knob.

Otherwise:

Acked-by: Fabiano Rosas <farosas@suse.de>
Cc: qemu-stable@nongnu.org