Re: [PATCH 01/17] pnv_phb3.c: add unique chassis and slot for pnv_phb3_root_port

[Cédric Le Goater]

On 12/28/21 20:37, Daniel Henrique Barboza wrote:
> 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.

I guess parent_realize() will fail if we add 2 root port devices under
the same phb ?

Thanks,

C.


> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
> ---
>   hw/pci-host/pnv_phb3.c | 16 ++++++++++++++++
>   1 file changed, 16 insertions(+)
>
> diff --git a/hw/pci-host/pnv_phb3.c b/hw/pci-host/pnv_phb3.c
> index 4e2d680d44..130d392b3e 100644
> --- a/hw/pci-host/pnv_phb3.c
> +++ b/hw/pci-host/pnv_phb3.c
> @@ -1156,8 +1156,24 @@ 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);