[PATCH v2 3/6] PCI: Set PCI_BUS_FLAGS_MSI_REMAP if IOMMU have capability of IRQ remapping

[Yongji Xie]

The capability of IRQ remapping is abstracted on IOMMU side on
some archs. There is a existing flag IOMMU_CAP_INTR_REMAP for this.

To have a universal flag to test this capability for different
archs on PCI side, we set PCI_BUS_FLAGS_MSI_REMAP for PCI buses
when IOMMU_CAP_INTR_REMAP is set.

Signed-off-by: Yongji Xie <xyjxie@xxxxxxxxxxxxxxxxxx>
---
 drivers/pci/probe.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 2b9e3ba..15a33e2 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -16,6 +16,7 @@
 #include <linux/aer.h>
 #include <linux/acpi.h>
 #include <linux/irqdomain.h>
+#include <linux/iommu.h>
 #include "pci.h"
 
 #define CARDBUS_LATENCY_TIMER	176	/* secondary latency timer */
@@ -2160,6 +2161,9 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
 	pci_set_bus_of_node(b);
 	pci_set_bus_msi_domain(b);
 
+	if (iommu_capable(&pci_bus_type, IOMMU_CAP_INTR_REMAP))
+		b->bus_flags |= PCI_BUS_FLAGS_MSI_REMAP;
+
 	if (!parent)
 		set_dev_node(b->bridge, pcibus_to_node(b));
 
-- 
1.7.9.5