diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 2adb475..aac5b15 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -10,6 +10,7 @@
 #include <linux/module.h>
 #include <linux/cpumask.h>
 #include <linux/pci-aspm.h>
+#include <linux/iommu.h>
 #include "pci.h"
 
 #define CARDBUS_LATENCY_TIMER	176	/* secondary latency timer */
@@ -1004,6 +1005,10 @@
 
 	/* Single Root I/O Virtualization */
 	pci_iov_init(dev);
+
+	/* Enable ACS P2P upstream forwarding */
+	if (iommu_found())
+		pci_enable_acs(dev);
 }
 
 void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)