Returns true if PCI device is aliased or false otherwise. This will be
used in following patch to determine if a PCI device is under a PCI
bridge.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
---
 include/hw/pci/pci.h |  2 ++
 hw/pci/pci.c         | 12 ++++++++----
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index 6bccb25ac2..bde9dca8e2 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -637,6 +637,8 @@ typedef struct PCIIOMMUOps {
                             bool is_write);
 } PCIIOMMUOps;
 
+bool pci_device_get_iommu_bus_devfn(PCIDevice *dev, PCIBus **piommu_bus,
+                                    PCIBus **aliased_bus, int *aliased_devfn);
 AddressSpace *pci_device_iommu_address_space(PCIDevice *dev);
 bool pci_device_set_iommu_device(PCIDevice *dev, HostIOMMUDevice *hiod,
                                  Error **errp);
diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index acc03fd470..d0e81651aa 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -2858,20 +2858,21 @@ static void pci_device_class_base_init(ObjectClass *klass, const void *data)
  * For call sites which don't need aliased BDF, passing NULL to
  * aliased_[bus|devfn] is allowed.
  *
+ * Returns true if PCI device RID is aliased or false otherwise.
+ *
  * @piommu_bus: return root #PCIBus backed by an IOMMU for the PCI device.
  *
  * @aliased_bus: return aliased #PCIBus of the PCI device, optional.
  *
  * @aliased_devfn: return aliased devfn of the PCI device, optional.
  */
-static void pci_device_get_iommu_bus_devfn(PCIDevice *dev,
-                                           PCIBus **piommu_bus,
-                                           PCIBus **aliased_bus,
-                                           int *aliased_devfn)
+bool pci_device_get_iommu_bus_devfn(PCIDevice *dev, PCIBus **piommu_bus,
+                                    PCIBus **aliased_bus, int *aliased_devfn)
 {
     PCIBus *bus = pci_get_bus(dev);
     PCIBus *iommu_bus = bus;
     int devfn = dev->devfn;
+    bool aliased = false;
 
     while (iommu_bus && !iommu_bus->iommu_ops && iommu_bus->parent_dev) {
         PCIBus *parent_bus = pci_get_bus(iommu_bus->parent_dev);
@@ -2908,6 +2909,7 @@ static void pci_device_get_iommu_bus_devfn(PCIDevice *dev,
                 devfn = parent->devfn;
                 bus = parent_bus;
             }
+            aliased = true;
         }
 
         /*
@@ -2942,6 +2944,8 @@ static void pci_device_get_iommu_bus_devfn(PCIDevice *dev,
     if (aliased_devfn) {
         *aliased_devfn = devfn;
     }
+
+    return aliased;
 }
 
 AddressSpace *pci_device_iommu_address_space(PCIDevice *dev)
-- 
2.47.1