Re: [Xen-devel] [PATCH v2 2/4] Extend device listener interface for PCI to PCI bridges

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

> -----Original Message-----
> From: Don Slutz [mailto:dslutz@xxxxxxxxxxx]
> Sent: 08 June 2015 22:19
> To: qemu-devel@xxxxxxxxxx; xen-devel@xxxxxxxxxxxxx
> Cc: Michael S. Tsirkin; Paul Durrant; Stefano Stabellini; Don Slutz; Don Slutz
> Subject: [PATCH v2 2/4] Extend device listener interface for PCI to PCI
> bridges
> 
> The commit 707ff80021ccd7a68f4b3d2c44eebf87efbb41c4 assumed that a
> PCI device has a static address.  This is not true for PCI devices
> that are on the secondary bus of a PCI to PCI bridge.
> 
> BIOS and/or guest OS can change the secondary bus number to a new
> value at any time.
> 
> Extend the device listener interface to be called when ever the
> secondary bus number is set to a new value.  This new interface
> is called for all PCI devices that are on the secondary bridge.
> 

Can't you just make unrealize and realize calls back-to-back when the bus 
number changes, rather than having a new callback?

  Paul

> Signed-off-by: Don Slutz <dslutz@xxxxxxxxxxx>
> CC: Don Slutz <don.slutz@xxxxxxxxx>
> ---
>  hw/core/qdev.c         |  7 +++++++
>  hw/pci/pci_bridge.c    | 18 ++++++++++++++++++
>  include/hw/qdev-core.h |  3 +++
>  3 files changed, 28 insertions(+)
> 
> diff --git a/hw/core/qdev.c b/hw/core/qdev.c
> index b0f0f84..7728ee7 100644
> --- a/hw/core/qdev.c
> +++ b/hw/core/qdev.c
> @@ -239,6 +239,13 @@ void device_listener_unregister(DeviceListener
> *listener)
>      QTAILQ_REMOVE(&device_listeners, listener, link);
>  }
> 
> +void device_listener_change_pci_bus_num(PCIBus *b, PCIDevice *d, void
> *opaque)
> +{
> +    uint8_t oldbus = GPOINTER_TO_INT(opaque);
> +
> +    DEVICE_LISTENER_CALL(change_pci_bus_num, Forward, d, oldbus);
> +}
> +
>  static void device_realize(DeviceState *dev, Error **errp)
>  {
>      DeviceClass *dc = DEVICE_GET_CLASS(dev);
> diff --git a/hw/pci/pci_bridge.c b/hw/pci/pci_bridge.c
> index 40c97b1..742c4d8 100644
> --- a/hw/pci/pci_bridge.c
> +++ b/hw/pci/pci_bridge.c
> @@ -248,6 +248,7 @@ void pci_bridge_write_config(PCIDevice *d,
>      PCIBridge *s = PCI_BRIDGE(d);
>      uint16_t oldctl = pci_get_word(d->config + PCI_BRIDGE_CONTROL);
>      uint16_t newctl;
> +    uint8_t oldbus = pci_get_byte(d->config + PCI_SECONDARY_BUS);
> 
>      pci_default_write_config(d, address, val, len);
> 
> @@ -265,6 +266,14 @@ void pci_bridge_write_config(PCIDevice *d,
>          pci_bridge_update_mappings(s);
>      }
> 
> +    if (oldbus != pci_get_byte(d->config + PCI_SECONDARY_BUS)) {
> +        PCIBus *sec_bus = pci_bridge_get_sec_bus(s);
> +
> +        pci_for_each_device(sec_bus, pci_bus_num(sec_bus),
> +                            device_listener_change_pci_bus_num,
> +                            GINT_TO_POINTER(oldbus));
> +    }
> +
>      newctl = pci_get_word(d->config + PCI_BRIDGE_CONTROL);
>      if (~oldctl & newctl & PCI_BRIDGE_CTL_BUS_RESET) {
>          /* Trigger hot reset on 0->1 transition. */
> @@ -297,6 +306,7 @@ void pci_bridge_reset(DeviceState *qdev)
>  {
>      PCIDevice *dev = PCI_DEVICE(qdev);
>      uint8_t *conf = dev->config;
> +    uint8_t oldbus = conf[PCI_SECONDARY_BUS];
> 
>      conf[PCI_PRIMARY_BUS] = 0;
>      conf[PCI_SECONDARY_BUS] = 0;
> @@ -329,6 +339,14 @@ void pci_bridge_reset(DeviceState *qdev)
>      pci_set_long(conf + PCI_PREF_LIMIT_UPPER32, 0);
> 
>      pci_set_word(conf + PCI_BRIDGE_CONTROL, 0);
> +
> +    if (oldbus) {
> +        PCIBus *sec_bus = pci_bridge_get_sec_bus(PCI_BRIDGE(dev));
> +
> +        pci_for_each_device(sec_bus, pci_bus_num(sec_bus),
> +                            device_listener_change_pci_bus_num,
> +                            GINT_TO_POINTER(oldbus));
> +    }
>  }
> 
>  /* default qdev initialization function for PCI-to-PCI bridge */
> diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
> index d4be92f..154b4c1 100644
> --- a/include/hw/qdev-core.h
> +++ b/include/hw/qdev-core.h
> @@ -168,6 +168,8 @@ struct DeviceState {
>  struct DeviceListener {
>      void (*realize)(DeviceListener *listener, DeviceState *dev);
>      void (*unrealize)(DeviceListener *listener, DeviceState *dev);
> +    void (*change_pci_bus_num)(DeviceListener *listener, PCIDevice *d,
> +                               uint8_t oldbus);
>      QTAILQ_ENTRY(DeviceListener) link;
>  };
> 
> @@ -387,5 +389,6 @@ static inline bool qbus_is_hotpluggable(BusState
> *bus)
> 
>  void device_listener_register(DeviceListener *listener);
>  void device_listener_unregister(DeviceListener *listener);
> +void device_listener_change_pci_bus_num(PCIBus *b, PCIDevice *d, void
> *opaque);
> 
>  #endif
> --
> 1.8.4


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