[Qemu-devel] [PATCH V6 for-2.3 13/26] hw/pci-host: introduce TYPE_PCI_HOST_BRIDGE_SNOOPED interface

[Marcel Apfelbaum <marcel@redhat.com>]

TYPE_PCI_HOST_BRIDGE_SNOOPED is a special case of host bridge
whose configuration registers are snooped by other host bridges
to complete their configuration cycles.

The interface exposes a list of snooping host bridges that
shall be used by the hosts implementing this interface
in order to emulate a snooping mechanism.

The way that the snooping hosts are registered or how
the snooping is implemented are out of the interface scope,
it only provides a way to determine if a host bridge has
snooping hosts and list them.

Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
---
 hw/pci/pci_host.c         |  8 ++++++++
 include/hw/pci/pci_host.h | 24 ++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/hw/pci/pci_host.c b/hw/pci/pci_host.c
index 87180c8..288e74c 100644
--- a/hw/pci/pci_host.c
+++ b/hw/pci/pci_host.c
@@ -180,6 +180,12 @@ static const TypeInfo pci_main_host_interface_info = {
     .parent        = TYPE_INTERFACE,
 };
 
+static const TypeInfo pci_host_bridge_snooped_interface_info = {
+    .name = TYPE_PCI_HOST_BRIDGE_SNOOPED,
+    .parent = TYPE_INTERFACE,
+    .class_size = sizeof(PCIHostBridgeSnoopedClass),
+};
+
 static const TypeInfo pci_host_type_info = {
     .name = TYPE_PCI_HOST_BRIDGE,
     .parent = TYPE_SYS_BUS_DEVICE,
@@ -191,7 +197,9 @@ static const TypeInfo pci_host_type_info = {
 static void pci_host_register_types(void)
 {
     type_register_static(&pci_main_host_interface_info);
+    type_register_static(&pci_host_bridge_snooped_interface_info);
     type_register_static(&pci_host_type_info);
+
 }
 
 type_init(pci_host_register_types)
diff --git a/include/hw/pci/pci_host.h b/include/hw/pci/pci_host.h
index 3c72e26..a041919 100644
--- a/include/hw/pci/pci_host.h
+++ b/include/hw/pci/pci_host.h
@@ -63,6 +63,30 @@ typedef struct PCIHostBridgeClass {
     const char *(*root_bus_path)(PCIHostState *, PCIBus *);
 } PCIHostBridgeClass;
 
+/**
+ * A special case of host bridge whose configuration registers
+ * are snooped by other host bridges to complete their
+ * configuration cycles.
+ */
+#define TYPE_PCI_HOST_BRIDGE_SNOOPED "pci-host-bridge-snooped"
+#define TYPE_PCI_HOST_BRIDGE_SNOOPED_CLASS(klass) \
+     OBJECT_CLASS_CHECK(PCIHostBridgeSnoopedClass, (klass), \
+                        TYPE_PCI_HOST_BRIDGE_SNOOPED)
+#define PCI_HOST_BRIDGE_SNOOPED_GET_CLASS(obj) \
+     OBJECT_GET_CLASS(PCIHostBridgeSnoopedClass, (obj), \
+                      TYPE_PCI_HOST_BRIDGE_SNOOPED)
+#define PCI_HOST_BRIDGE_SNOOPED(obj) \
+     INTERFACE_CHECK(PCIHostState, (obj), \
+                     TYPE_PCI_HOST_BRIDGE_SNOOPED)
+
+typedef struct PCIHostBridgeSnoopedClass {
+    /* <private> */
+    InterfaceClass parent_class;
+
+    /* <public> */
+    GPtrArray *(*snooping_hosts)(PCIHostState *);
+} PCIHostBridgeSnoopedClass;
+
 /* common internal helpers for PCI/PCIe hosts, cut off overflows */
 void pci_host_config_write_common(PCIDevice *pci_dev, uint32_t addr,
                                   uint32_t limit, uint32_t val, uint32_t len);
-- 
2.1.0