Re: [PATCH v1] s390/vfio-ap: Signal eventfd when guest AP configuration is changed

Anthony Krowiak
2025-01-16T16:46:09Z

>
> Rorie, this is to inform listeners on the host of the guest.
> The guest itself already sees this "inside" with uevents triggered
> by the AP bus code.
>
> Do you have a consumer for these events?

There is a series of QEMU patches that register a notification handler
for this
event. When that handler gets called, it generates and queues a CRW to
the guest
indicating there is event information pending which will cause the AP
bus driver
to get notified of the AP configuration change via its ap_bus_cfg_chg
notifier call.

The QEMU series can be seen at:
https://lore.kernel.org/qemu-devel/7171c479-5cb4-4748-ba37-da4cf2fac35b@linux.ibm.com/T/

Kind regards,
A Krowiak