diff --git a/drivers/xen/platform-pci.c b/drivers/xen/platform-pci.c
index 9db557b76511..18f0ed8b1f93 100644
--- a/drivers/xen/platform-pci.c
+++ b/drivers/xen/platform-pci.c
@@ -132,6 +132,13 @@ static int platform_pci_probe(struct pci_dev *pdev,
 			dev_warn(&pdev->dev, "request_irq failed err=%d\n", ret);
 			goto out;
 		}
+		/*
+		 * It doesn't strictly *have* to run on CPU0 but it sure
+		 * as hell better process the event channel ports delivered
+		 * to CPU0.
+		 */
+		irq_set_affinity(pdev->irq, cpumask_of(0));
+
 		callback_via = get_callback_via(pdev);
 		ret = xen_set_callback_via(callback_via);
 		if (ret) {