Re: [PATCH v2 5/5] hw/pci: ensure PCIE devices are plugged into only slot 0 of PCIE port

[Julia Suvorova]

On Thu, Jun 22, 2023 at 12:34 PM Ani Sinha <anisinha@redhat.com> wrote:
>
> PCI Express ports only have one slot, so PCI Express devices can only be
> plugged into slot 0 on a PCIE port. Enforce it.
>
> CC: jusual@redhat.com
> CC: imammedo@redhat.com
> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2128929
> Signed-off-by: Ani Sinha <anisinha@redhat.com>
> ---
>  hw/pci/pci.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index bf38905b7d..5f25ab9f5e 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -64,6 +64,7 @@ bool pci_available = true;
>  static char *pcibus_get_dev_path(DeviceState *dev);
>  static char *pcibus_get_fw_dev_path(DeviceState *dev);
>  static void pcibus_reset(BusState *qbus);
> +static bool pcie_has_upstream_port(PCIDevice *dev);
>
>  static Property pci_props[] = {
>      DEFINE_PROP_PCI_DEVFN("addr", PCIDevice, devfn, -1),
> @@ -1189,6 +1190,11 @@ static PCIDevice *do_pci_register_device(PCIDevice 
> *pci_dev,
>                     name);
>
>         return NULL;
> +    } else if (pcie_has_upstream_port(pci_dev) && PCI_SLOT(devfn)) {
> +        error_setg(errp, "PCI: slot %d is not valid for %s,"
> +                   " PCI express devices can only be plugged into slot 0.",

This is not technically correct, because downstream ports and root
ports are also PCIe devices, and they can have different slots under
upstream ports and RC. But this error will never be shown for them, so
it seems fine.

Reviewed-by: Julia Suvorova <jusual@redhat.com>




> +                   PCI_SLOT(devfn), name);
> +        return NULL;
>      }
>
>      pci_dev->devfn = devfn;
> --
> 2.39.1
>