xen/events: reset affinity of 2-level event when tearing it down

When creating a new event channel with 2-level events the affinity
needs to be reset initially in order to avoid using an old affinity
from earlier usage of the event channel port. So when tearing an event
channel down reset all affinity bits.

The same applies to the affinity when onlining a vcpu: all old
affinity settings for this vcpu must be reset. As percpu events get
initialized before the percpu event channel hook is called,
resetting of the affinities happens after offlining a vcpu (this is
working, as initial percpu memory is zeroed out).

Cc: stable@vger.kernel.org
Reported-by: Julien Grall <julien@xen.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Link: https://lore.kernel.org/r/20210306161833.4552-2-jgross@suse.com
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/xen/events/events_internal.h b/drivers/xen/events/events_internal.h
index 0a97c0549db7..18a4090d0709 100644
--- a/drivers/xen/events/events_internal.h
+++ b/drivers/xen/events/events_internal.h
@@ -14,6 +14,7 @@ struct evtchn_ops {
 	unsigned (*nr_channels)(void);
 
 	int (*setup)(evtchn_port_t port);
+	void (*remove)(evtchn_port_t port, unsigned int cpu);
 	void (*bind_to_cpu)(evtchn_port_t evtchn, unsigned int cpu,
 			    unsigned int old_cpu);
 
@@ -54,6 +55,13 @@ static inline int xen_evtchn_port_setup(evtchn_port_t evtchn)
 	return 0;
 }
 
+static inline void xen_evtchn_port_remove(evtchn_port_t evtchn,
+					  unsigned int cpu)
+{
+	if (evtchn_ops->remove)
+		evtchn_ops->remove(evtchn, cpu);
+}
+
 static inline void xen_evtchn_port_bind_to_cpu(evtchn_port_t evtchn,
 					       unsigned int cpu,
 					       unsigned int old_cpu)