Re: [Qemu-devel] [PATCH] hw/pci-bridge: check invalid slot number for root and downstream port

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Dec 05, 2018 at 05:41:26PM +0800, Huan Xiong wrote:
> Since root and downstream port have only one slot, device should be
> connected to them using slot 0. QEMU doesn't have a check for that
> and starts up when a non-zero slot is specified, though the device
> is not seen in guest OS.
> 
> The change fixes that by adding a check in PCI device "attr" property
> setter function. The check is performed only if a PCI device has been
> connected to a bus, otherwise it does nothing. The latter occurs because
> setter function is also called in object instantiation phase to set
> property default value.
> 
> Signed-off-by: Huan Xiong <huan.xiong@hxt-semitech.com>

I thought that a non 0 slot is useful for ARI. No?


> ---
>  hw/core/qdev-properties.c          |  5 ++++-
>  hw/pci-bridge/pcie_root_port.c     |  2 +-
>  hw/pci-bridge/xio3130_downstream.c |  2 +-
>  hw/pci/pci.c                       | 13 +++++++++++++
>  include/hw/pci/pci.h               |  1 +
>  5 files changed, 20 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
> index 35072de..6e79219 100644
> --- a/hw/core/qdev-properties.c
> +++ b/hw/core/qdev-properties.c
> @@ -654,6 +654,8 @@ static void set_pci_devfn(Object *obj, Visitor *v, const char *name,
>                            void *opaque, Error **errp)
>  {
>      DeviceState *dev = DEVICE(obj);
> +    BusState *bus = qdev_get_parent_bus(dev);
> +    BusClass *bus_class = bus ? BUS_GET_CLASS(bus) : NULL;
>      Property *prop = opaque;
>      int32_t value, *ptr = qdev_get_prop_ptr(dev, prop);
>      unsigned int slot, fn, n;
> @@ -687,7 +689,8 @@ static void set_pci_devfn(Object *obj, Visitor *v, const char *name,
>              goto invalid;
>          }
>      }
> -    if (str[n] != '\0' || fn > 7 || slot > 31) {
> +    if (str[n] != '\0' || fn > 7 || slot > 31 || (bus_class &&
> +        bus_class->max_dev != 0 && slot >= bus_class->max_dev)) {
>          goto invalid;
>      }

This looks kind of complicated. Isn't there an easier way?

>      *ptr = slot << 3 | fn;
> diff --git a/hw/pci-bridge/pcie_root_port.c b/hw/pci-bridge/pcie_root_port.c
> index 45f9e8c..ee42411 100644
> --- a/hw/pci-bridge/pcie_root_port.c
> +++ b/hw/pci-bridge/pcie_root_port.c
> @@ -61,7 +61,7 @@ static void rp_realize(PCIDevice *d, Error **errp)
>      int rc;
>  
>      pci_config_set_interrupt_pin(d->config, 1);
> -    pci_bridge_initfn(d, TYPE_PCIE_BUS);
> +    pci_bridge_initfn(d, TYPE_PCIE_DOWNSTREAM_BUS);
>      pcie_port_init_reg(d);
>  
>      rc = pci_bridge_ssvid_init(d, rpc->ssvid_offset, dc->vendor_id,
> diff --git a/hw/pci-bridge/xio3130_downstream.c b/hw/pci-bridge/xio3130_downstream.c
> index 467bbab..960a90c 100644
> --- a/hw/pci-bridge/xio3130_downstream.c
> +++ b/hw/pci-bridge/xio3130_downstream.c
> @@ -62,7 +62,7 @@ static void xio3130_downstream_realize(PCIDevice *d, Error **errp)
>      PCIESlot *s = PCIE_SLOT(d);
>      int rc;
>  
> -    pci_bridge_initfn(d, TYPE_PCIE_BUS);
> +    pci_bridge_initfn(d, TYPE_PCIE_DOWNSTREAM_BUS);
>      pcie_port_init_reg(d);
>  
>      rc = msi_init(d, XIO3130_MSI_OFFSET, XIO3130_MSI_NR_VECTOR,
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index 56b13b3..457736d 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -187,6 +187,18 @@ static const TypeInfo pcie_bus_info = {
>      .parent = TYPE_PCI_BUS,
>  };
>  
> +static void pcie_downstream_bus_class_init(ObjectClass *klass, void *data)
> +{
> +    BusClass *k = BUS_CLASS(klass);
> +    k->max_dev = 1;
> +}
> +
> +static const TypeInfo pcie_downstream_bus_info = {
> +    .name = TYPE_PCIE_DOWNSTREAM_BUS,
> +    .parent = TYPE_PCIE_BUS,
> +    .class_init = pcie_downstream_bus_class_init,
> +};
> +
>  static PCIBus *pci_find_bus_nr(PCIBus *bus, int bus_num);
>  static void pci_update_mappings(PCIDevice *d);
>  static void pci_irq_handler(void *opaque, int irq_num, int level);
> @@ -2681,6 +2693,7 @@ static void pci_register_types(void)
>  {
>      type_register_static(&pci_bus_info);
>      type_register_static(&pcie_bus_info);
> +    type_register_static(&pcie_downstream_bus_info);
>      type_register_static(&conventional_pci_interface_info);
>      type_register_static(&pcie_interface_info);
>      type_register_static(&pci_device_type_info);
> diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
> index e6514bb..2253757 100644
> --- a/include/hw/pci/pci.h
> +++ b/include/hw/pci/pci.h
> @@ -393,6 +393,7 @@ typedef PCIINTxRoute (*pci_route_irq_fn)(void *opaque, int pin);
>  #define PCI_BUS_CLASS(klass) OBJECT_CLASS_CHECK(PCIBusClass, (klass), TYPE_PCI_BUS)
>  #define PCI_BUS_GET_CLASS(obj) OBJECT_GET_CLASS(PCIBusClass, (obj), TYPE_PCI_BUS)
>  #define TYPE_PCIE_BUS "PCIE"
> +#define TYPE_PCIE_DOWNSTREAM_BUS "PCIE-downstream"
>  
>  bool pci_bus_is_express(PCIBus *bus);
>  bool pci_bus_is_root(PCIBus *bus);
> -- 
> 2.7.4