pnv_phb3.c: add unique chassis and slot for pnv_phb3_root_port

When creating a pnv_phb3_root_port using the command line, the first
root port is created successfully, but the second fails with the
following error:

qemu-system-ppc64: -device pnv-phb3-root-port,bus=phb3-root.0,id=pcie.3:
Can't add chassis slot, error -16

This error comes from the realize() function of its parent type,
rp_realize() from TYPE_PCIE_ROOT_PORT. pcie_chassis_add_slot() fails
with -EBUSY if there's an existing PCIESlot that has the same
chassis/slot value, regardless of being in a different bus.

One way to prevent this error is simply set chassis and slot values in
the command line. However, since phb3 root buses only supports a single
root port, we can just get an unique chassis/slot value by checking
which root bus the pnv_phb3_root_port is going to be attached, get the
equivalent phb3 device and use its chip-id and index values, which are
guaranteed to be unique.

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20220105212338.49899-2-danielhb413@gmail.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/hw/pci-host/pnv_phb3.c b/hw/pci-host/pnv_phb3.c
index c78084c..3467bbb 100644
--- a/hw/pci-host/pnv_phb3.c
+++ b/hw/pci-host/pnv_phb3.c
@@ -1142,8 +1142,24 @@ static const TypeInfo pnv_phb3_root_bus_info = {
 static void pnv_phb3_root_port_realize(DeviceState *dev, Error **errp)
 {
     PCIERootPortClass *rpc = PCIE_ROOT_PORT_GET_CLASS(dev);
+    PCIDevice *pci = PCI_DEVICE(dev);
+    PCIBus *bus = pci_get_bus(pci);
+    PnvPHB3 *phb = NULL;
     Error *local_err = NULL;
 
+    phb = (PnvPHB3 *) object_dynamic_cast(OBJECT(bus->qbus.parent),
+                                          TYPE_PNV_PHB3);
+
+    if (!phb) {
+        error_setg(errp,
+"pnv_phb3_root_port devices must be connected to pnv-phb3 buses");
+        return;
+    }
+
+    /* Set unique chassis/slot values for the root port */
+    qdev_prop_set_uint8(&pci->qdev, "chassis", phb->chip_id);
+    qdev_prop_set_uint16(&pci->qdev, "slot", phb->phb_id);
+
     rpc->parent_realize(dev, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);