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: stable@vger.kernel.org Signed-off-by: Jason Andryuk jason.andryuk@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;