| From 3de218ff39b9e3f0d453fe3154f12a174de44b25 Mon Sep 17 00:00:00 2001 |
| From: Juergen Gross <jgross@suse.com> |
| Date: Wed, 23 Jun 2021 15:09:13 +0200 |
| Subject: xen/events: reset active flag for lateeoi events later |
| |
| From: Juergen Gross <jgross@suse.com> |
| |
| commit 3de218ff39b9e3f0d453fe3154f12a174de44b25 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: Julien Grall <julien@xen.org> |
| Fixes: b6622798bc50b62 ("xen/events: avoid handling the same event on two cpus at the same time") |
| Tested-by: Julien Grall <julien@xen.org> |
| Signed-off-by: Juergen Gross <jgross@suse.com> |
| Reviewed-by: Boris Ostrovsky <boris.ostrvsky@oracle.com> |
| Link: https://lore.kernel.org/r/20210623130913.9405-1-jgross@suse.com |
| Signed-off-by: Juergen Gross <jgross@suse.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/xen/events/events_base.c | 23 +++++++++++++++++++---- |
| 1 file changed, 19 insertions(+), 4 deletions(-) |
| |
| --- a/drivers/xen/events/events_base.c |
| +++ b/drivers/xen/events/events_base.c |
| @@ -533,6 +533,9 @@ static void xen_irq_lateeoi_locked(struc |
| } |
| |
| 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); |
| } |
| |
| @@ -1777,10 +1780,22 @@ static void lateeoi_ack_dynirq(struct ir |
| 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) |