[RFC QEMU PATCH 07/10] cxl-downstream-port: Add support for VCS switching

[Joshua Lant <joshualant@gmail.com>]

When a downstream port is connnected to an upstream port which is
defined as a VCS within a cxl-vcs-switch, the port will automatically be
instantiated as a VPPB within that VCS. This downstream port will then
appear normally to the guest, but can be connected to a real downstream
PPB at runtime when the switch is issued a bind command by the Fabric
Manager.

Signed-off-by: Joshua Lant <joshualant@gmail.com>
---
 hw/pci-bridge/cxl_downstream.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/hw/pci-bridge/cxl_downstream.c b/hw/pci-bridge/cxl_downstream.c
index 5322c46900..5e7ce6410d 100644
--- a/hw/pci-bridge/cxl_downstream.c
+++ b/hw/pci-bridge/cxl_downstream.c
@@ -14,11 +14,14 @@
 #include "hw/pci/pcie.h"
 #include "hw/pci/pcie_port.h"
 #include "hw/pci-bridge/cxl_downstream_port.h"
+#include "hw/pci-bridge/cxl_upstream_port.h"
 #include "hw/qdev-properties.h"
 #include "hw/qdev-properties-system.h"
 #include "hw/cxl/cxl.h"
 #include "hw/cxl/cxl_port.h"
 #include "qapi/error.h"
+#include "hw/cxl/cxl_vcs_switch.h"
+
 
 typedef struct CXLDownstreamPort {
     /*< private >*/
@@ -199,6 +202,14 @@ static void cxl_dsp_realize(PCIDevice *d, Error **errp)
                          PCI_BASE_ADDRESS_MEM_TYPE_64,
                      component_bar);
 
+    PCIDevice *parent = pci_bridge_get_device(pci_get_bus(PCI_DEVICE(d)));
+    if (parent && object_dynamic_cast(OBJECT(parent), TYPE_CXL_USP)) {
+        CXLUpstreamPort *usp = CXL_USP(parent);
+        if (usp->vcs_name) {
+            cxl_vcs_register_vppb(usp->swcci.vcs, usp, dsp, errp);
+        }
+    }
+
     return;
 
  err_chassis:
-- 
2.47.3