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

[Harsh Prateek Bora <harshpb@linux.ibm.com>]

+ Gautam, Glenn

Hi Fabian,


On 8/19/25 08:25, Fabiano Rosas wrote:
> 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.

Since this affected only guests using XICS, would it be a better idea to 
mention this explicitly in commit log as well (?

> 
> 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.

Gautam, Glenn - thoughts on above comments?

Thanks for the patch.

regards,
Harsh

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