[PATCH v2 4/5] pci: Add pci_for_each_root_bus()

[Peter Xu <peterx@redhat.com>]

Add a helper to loop over each root bus of the system, either the default root
bus or extended buses like pxb-pcie.

There're three places that can be rewritten with the pci_for_each_root_bus()
helper that we just introduced.  De-dup the code.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 hw/arm/virt-acpi-build.c | 31 +++++++++++--------------------
 hw/i386/acpi-build.c     | 38 ++++++++++----------------------------
 hw/pci/pci.c             | 26 ++++++++++++++++++++++++++
 include/hw/pci/pci.h     |  2 ++
 4 files changed, 49 insertions(+), 48 deletions(-)

diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
index 674f902652..adba51f35a 100644
--- a/hw/arm/virt-acpi-build.c
+++ b/hw/arm/virt-acpi-build.c
@@ -264,28 +264,20 @@ struct AcpiIortIdMapping {
 typedef struct AcpiIortIdMapping AcpiIortIdMapping;
 
 /* Build the iort ID mapping to SMMUv3 for a given PCI host bridge */
-static int
-iort_host_bridges(Object *obj, void *opaque)
+static void
+iort_host_bridges(PCIBus *bus, void *opaque)
 {
-    GArray *idmap_blob = opaque;
-
-    if (object_dynamic_cast(obj, TYPE_PCI_HOST_BRIDGE)) {
-        PCIBus *bus = PCI_HOST_BRIDGE(obj)->bus;
-
-        if (bus && !pci_bus_bypass_iommu(bus)) {
-            int min_bus, max_bus;
+    if (!pci_bus_bypass_iommu(bus)) {
+        int min_bus, max_bus;
 
-            pci_bus_range(bus, &min_bus, &max_bus);
+        pci_bus_range(bus, &min_bus, &max_bus);
 
-            AcpiIortIdMapping idmap = {
-                .input_base = min_bus << 8,
-                .id_count = (max_bus - min_bus + 1) << 8,
-            };
-            g_array_append_val(idmap_blob, idmap);
-        }
+        AcpiIortIdMapping idmap = {
+            .input_base = min_bus << 8,
+            .id_count = (max_bus - min_bus + 1) << 8,
+        };
+        g_array_append_val((GArray *)opaque, idmap);
     }
-
-    return 0;
 }
 
 static int iort_idmap_compare(gconstpointer a, gconstpointer b)
@@ -320,8 +312,7 @@ build_iort(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
     if (vms->iommu == VIRT_IOMMU_SMMUV3) {
         AcpiIortIdMapping next_range = {0};
 
-        object_child_foreach_recursive(object_get_root(),
-                                       iort_host_bridges, smmu_idmaps);
+        pci_for_each_root_bus(iort_host_bridges, smmu_idmaps);
 
         /* Sort the smmu idmap by input_base */
         g_array_sort(smmu_idmaps, iort_idmap_compare);
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index a76b17ed92..3e50acfe35 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -2123,20 +2123,12 @@ insert_scope(PCIBus *bus, PCIDevice *dev, void *opaque)
 }
 
 /* For a given PCI host bridge, walk and insert DMAR scope */
-static int
-dmar_host_bridges(Object *obj, void *opaque)
+static void
+dmar_host_bridges(PCIBus *bus, void *opaque)
 {
-    GArray *scope_blob = opaque;
-
-    if (object_dynamic_cast(obj, TYPE_PCI_HOST_BRIDGE)) {
-        PCIBus *bus = PCI_HOST_BRIDGE(obj)->bus;
-
-        if (bus && !pci_bus_bypass_iommu(bus)) {
-            pci_for_each_device_under_bus(bus, insert_scope, scope_blob);
-        }
+    if (!pci_bus_bypass_iommu(bus)) {
+        pci_for_each_device_under_bus(bus, insert_scope, opaque);
     }
-
-    return 0;
 }
 
 /*
@@ -2165,8 +2157,7 @@ build_dmar_q35(GArray *table_data, BIOSLinker *linker, const char *oem_id,
      * Insert scope for each PCI bridge and endpoint device which
      * is attached to a bus with iommu enabled.
      */
-    object_child_foreach_recursive(object_get_root(),
-                                   dmar_host_bridges, scope_blob);
+    pci_for_each_root_bus(dmar_host_bridges, scope_blob);
 
     assert(iommu);
     if (x86_iommu_ir_supported(iommu)) {
@@ -2329,20 +2320,12 @@ insert_ivhd(PCIBus *bus, PCIDevice *dev, void *opaque)
 }
 
 /* For all PCI host bridges, walk and insert IVHD entries */
-static int
-ivrs_host_bridges(Object *obj, void *opaque)
+static void
+ivrs_host_bridges(PCIBus *bus, void *opaque)
 {
-    GArray *ivhd_blob = opaque;
-
-    if (object_dynamic_cast(obj, TYPE_PCI_HOST_BRIDGE)) {
-        PCIBus *bus = PCI_HOST_BRIDGE(obj)->bus;
-
-        if (bus && !pci_bus_bypass_iommu(bus)) {
-            pci_for_each_device_under_bus(bus, insert_ivhd, ivhd_blob);
-        }
+    if (!pci_bus_bypass_iommu(bus)) {
+        pci_for_each_device_under_bus(bus, insert_ivhd, opaque);
     }
-
-    return 0;
 }
 
 static void
@@ -2380,8 +2363,7 @@ build_amd_iommu(GArray *table_data, BIOSLinker *linker, const char *oem_id,
      * blob further below.  Fall back to an entry covering all devices, which
      * is sufficient when no aliases are present.
      */
-    object_child_foreach_recursive(object_get_root(),
-                                   ivrs_host_bridges, ivhd_blob);
+    pci_for_each_root_bus(ivrs_host_bridges, ivhd_blob);
 
     if (!ivhd_blob->len) {
         /*
diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 4a84e478ce..258290f4eb 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -2097,6 +2097,32 @@ void pci_for_each_bus_depth_first(PCIBus *bus, pci_bus_ret_fn begin,
     }
 }
 
+typedef struct {
+    pci_bus_fn fn;
+    void *opaque;
+} PCIRootBusArgs;
+
+static int pci_find_root_bus(Object *obj, void *opaque)
+{
+    PCIRootBusArgs *args = opaque;
+    PCIBus *bus = PCI_HOST_BRIDGE(obj)->bus;
+
+    if (bus) {
+        args->fn(bus, args->opaque);
+    }
+
+    return 0;
+}
+
+void pci_for_each_root_bus(pci_bus_fn fn, void *opaque)
+{
+    PCIRootBusArgs args = { .fn = fn, .opaque = opaque };
+
+    object_child_foreach_recursive_type(object_get_root(),
+                                        TYPE_PCI_HOST_BRIDGE,
+                                        pci_find_root_bus,
+                                        &args);
+}
 
 PCIDevice *pci_find_device(PCIBus *bus, int bus_num, uint8_t devfn)
 {
diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index 5c4016b995..6813f128e0 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -474,6 +474,8 @@ void pci_for_each_device_under_bus_reverse(PCIBus *bus,
                                            void *opaque);
 void pci_for_each_bus_depth_first(PCIBus *bus, pci_bus_ret_fn begin,
                                   pci_bus_fn end, void *parent_state);
+/* Call `fn' for each pci root bus on the system */
+void pci_for_each_root_bus(pci_bus_fn fn, void *opaque);
 PCIDevice *pci_get_function_0(PCIDevice *pci_dev);
 
 /* Use this wrapper when specific scan order is not required. */
-- 
2.32.0