genirq: Let irq_set_vcpu_affinity() iterate over hierarchy

When assigning an interrupt to a vcpu, it is not unlikely that
the level of the hierarchy implementing irq_set_vcpu_affinity
is not the top level (think a generic MSI domain on top of a
virtualization aware interrupt controller).

In such a case, let's iterate over the hierarchy until we find
an irqchip implementing it.

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

1 files changed, 12 insertions, 2 deletions

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 1d1a5b945ab4..573dc52b0806 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -400,8 +400,18 @@ int irq_set_vcpu_affinity(unsigned int irq, void *vcpu_info)
                 return -EINVAL;
 
         data = irq_desc_get_irq_data(desc);
-        chip = irq_data_get_irq_chip(data);
-        if (chip && chip->irq_set_vcpu_affinity)
+        do {
+                chip = irq_data_get_irq_chip(data);
+                if (chip && chip->irq_set_vcpu_affinity)
+                        break;
+#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+                data = data->parent_data;
+#else
+                data = NULL;
+#endif
+        } while (data);
+
+        if (data)
                 ret = chip->irq_set_vcpu_affinity(data, vcpu_info);
         irq_put_desc_unlock(desc, flags);