xen/events: reset active flag for lateeoi events later

stable inclusion
from stable-5.10.49
commit 064b57a8da995ee0b97b505ae8ca478eff87c331
bugzilla: 174521 https://gitee.com/openeuler/kernel/issues/I4DGQS

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=064b57a8da995ee0b97b505ae8ca478eff87c331

--------------------------------

commit 3de218ff upstream.

In order to avoid a race condition for user events when changing
cpu affinity reset the active flag only when EOI-ing the event.

This is working fine as all user events are lateeoi events. Note that
lateeoi_ack_mask_dynirq() is not modified as there is no explicit call
to xen_irq_lateeoi() expected later.

Cc: stable@vger.kernel.org
Reported-by: NJulien Grall <julien@xen.org>
Fixes: b6622798 ("xen/events: avoid handling the same event on two cpus at the same time")
Tested-by: NJulien Grall <julien@xen.org>
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NBoris Ostrovsky <boris.ostrvsky@oracle.com>
Link: https://lore.kernel.org/r/20210623130913.9405-1-jgross@suse.comSigned-off-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/xen/events/events_base.c

@@ -583,6 +583,9 @@ static void xen_irq_lateeoi_locked(struct irq_info *info, bool spurious)
 	}
 
 	info->eoi_time = 0;
+
+	/* is_active hasn't been reset yet, do it now. */
+	smp_store_release(&info->is_active, 0);
 	do_unmask(info, EVT_MASK_REASON_EOI_PENDING);
 }
 
@@ -1807,10 +1810,22 @@ static void lateeoi_ack_dynirq(struct irq_data *data)
 	struct irq_info *info = info_for_irq(data->irq);
 	evtchn_port_t evtchn = info ? info->evtchn : 0;
 
-	if (VALID_EVTCHN(evtchn)) {
-		do_mask(info, EVT_MASK_REASON_EOI_PENDING);
-		ack_dynirq(data);
-	}
+	if (!VALID_EVTCHN(evtchn))
+		return;
+
+	do_mask(info, EVT_MASK_REASON_EOI_PENDING);
+
+	if (unlikely(irqd_is_setaffinity_pending(data)) &&
+	    likely(!irqd_irq_disabled(data))) {
+		do_mask(info, EVT_MASK_REASON_TEMPORARY);
+
+		clear_evtchn(evtchn);
+
+		irq_move_masked_irq(data);
+
+		do_unmask(info, EVT_MASK_REASON_TEMPORARY);
+	} else
+		clear_evtchn(evtchn);
 }
 
 static void lateeoi_mask_ack_dynirq(struct irq_data *data)