VIRQs come in 3 flavors, per-VPU, per-domain, and global, and the VIRQs
are tracked in per-cpu virq_to_irq arrays.
Per-domain and global VIRQs must be bound on CPU 0, and
bind_virq_to_irq() sets the per_cpu virq_to_irq at registration time
Later, the interrupt can migrate, and info->cpu is updated. When
calling __unbind_from_irq(), the per-cpu virq_to_irq is cleared for a
different cpu. If bind_virq_to_irq() is called again with CPU 0, the
stale irq is returned. There won't be any irq_info for the irq, so
things break.
Make xen_rebind_evtchn_to_cpu() update the per_cpu virq_to_irq mappings
to keep them update to date with the current cpu. This ensures the
correct virq_to_irq is cleared in __unbind_from_irq().
Fixes: e46cdb66c8fc ("xen: event channels")
Cc: sta...@vger.kernel.org
Signed-off-by: Jason Andryuk <jason.andr...@amd.com>
---
v3:
Kernel style brace placement
Delay setting old_cpu and tighten scope of variable
v2:
Different approach changing virq_to_irq
---
drivers/xen/events/events_base.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index b060b5a95f45..9478fae014e5 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -1797,9 +1797,20 @@ static int xen_rebind_evtchn_to_cpu(struct irq_info
*info, unsigned int tcpu)
* virq or IPI channel, which don't actually need to be rebound. Ignore
* it, but don't do the xenlinux-level rebind in that case.
*/
- if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0)
+ if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0) {
+ int old_cpu = info->cpu;
+
bind_evtchn_to_cpu(info, tcpu, false);
+ if (info->type == IRQT_VIRQ) {
+ int virq = info->u.virq;
+ int irq = per_cpu(virq_to_irq, old_cpu)[virq];
+
+ per_cpu(virq_to_irq, old_cpu)[virq] = -1;
+ per_cpu(virq_to_irq, tcpu)[virq] = irq;
+ }
+ }
+
do_unmask(info, EVT_MASK_REASON_TEMPORARY);
return 0;
--
2.34.1
