pci-bridge/cxl_downstream: Add a CXL switch downstream port

Emulation of a simple CXL Switch downstream port.
The Device ID has been allocated for this use.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20220616145126.8002-3-Jonathan.Cameron@huawei.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 41 insertions, 2 deletions

diff --git a/hw/cxl/cxl-host.c b/hw/cxl/cxl-host.c
index efa14908d8..483d8eb13f 100644
--- a/hw/cxl/cxl-host.c
+++ b/hw/cxl/cxl-host.c
@@ -129,8 +129,9 @@ static bool cxl_hdm_find_target(uint32_t *cache_mem, hwaddr addr,
 
 static PCIDevice *cxl_cfmws_find_device(CXLFixedWindow *fw, hwaddr addr)
 {
-    CXLComponentState *hb_cstate;
+    CXLComponentState *hb_cstate, *usp_cstate;
     PCIHostState *hb;
+    CXLUpstreamPort *usp;
     int rb_index;
     uint32_t *cache_mem;
     uint8_t target;
@@ -164,8 +165,46 @@ static PCIDevice *cxl_cfmws_find_device(CXLFixedWindow *fw, hwaddr addr)
     }
 
     d = pci_bridge_get_sec_bus(PCI_BRIDGE(rp))->devices[0];
+    if (!d) {
+        return NULL;
+    }
+
+    if (object_dynamic_cast(OBJECT(d), TYPE_CXL_TYPE3)) {
+        return d;
+    }
+
+    /*
+     * Could also be a switch.  Note only one level of switching currently
+     * supported.
+     */
+    if (!object_dynamic_cast(OBJECT(d), TYPE_CXL_USP)) {
+        return NULL;
+    }
+    usp = CXL_USP(d);
+
+    usp_cstate = cxl_usp_to_cstate(usp);
+    if (!usp_cstate) {
+        return NULL;
+    }
+
+    cache_mem = usp_cstate->crb.cache_mem_registers;
+
+    target_found = cxl_hdm_find_target(cache_mem, addr, &target);
+    if (!target_found) {
+        return NULL;
+    }
+
+    d = pcie_find_port_by_pn(&PCI_BRIDGE(d)->sec_bus, target);
+    if (!d) {
+        return NULL;
+    }
+
+    d = pci_bridge_get_sec_bus(PCI_BRIDGE(d))->devices[0];
+    if (!d) {
+        return NULL;
+    }
 
-    if (!d || !object_dynamic_cast(OBJECT(d), TYPE_CXL_TYPE3)) {
+    if (!object_dynamic_cast(OBJECT(d), TYPE_CXL_TYPE3)) {
         return NULL;
     }