Re: [PATCH for-6.0 3/4] hw/arm/virt: Only try to add valid dynamic sysbus devices to platform bus

[Auger Eric]

Hi Peter,

On 3/25/21 4:33 PM, Peter Maydell wrote:
> The virt machine device plug callback currently calls
> platform_bus_link_device() for any sysbus device.  This is overly
> broad, because platform_bus_link_device() will unconditionally grab
> the IRQs and MMIOs of the device it is passed, whether it was
> intended for the platform bus or not.  Restrict hotpluggability of
> sysbus devices to only those devices on the dynamic sysbus whitelist.
> 
> We were mostly getting away with this because the board creates the
> platform bus as the last device it creates, and so the hotplug
> callback did not do anything for all the sysbus devices created by
> the board itself.  However if the user plugged in a device which
> itself uses a sysbus device internally we would have mishandled this
> and probably asserted.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>

Thanks

Eric
> ---
>  hw/arm/virt.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index aa2bbd14e09..8625152a735 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -2443,7 +2443,9 @@ static void virt_machine_device_plug_cb(HotplugHandler 
> *hotplug_dev,
>      VirtMachineState *vms = VIRT_MACHINE(hotplug_dev);
>  
>      if (vms->platform_bus_dev) {
> -        if (object_dynamic_cast(OBJECT(dev), TYPE_SYS_BUS_DEVICE)) {
> +        MachineClass *mc = MACHINE_GET_CLASS(vms);
> +
> +        if (device_is_dynamic_sysbus(mc, dev)) {
>              
> platform_bus_link_device(PLATFORM_BUS_DEVICE(vms->platform_bus_dev),
>                                       SYS_BUS_DEVICE(dev));
>          }
> @@ -2527,7 +2529,9 @@ static void 
> virt_machine_device_unplug_cb(HotplugHandler *hotplug_dev,
>  static HotplugHandler *virt_machine_get_hotplug_handler(MachineState 
> *machine,
>                                                          DeviceState *dev)
>  {
> -    if (object_dynamic_cast(OBJECT(dev), TYPE_SYS_BUS_DEVICE) ||
> +    MachineClass *mc = MACHINE_GET_CLASS(machine);
> +
> +    if (device_is_dynamic_sysbus(mc, dev) ||
>         (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM))) {
>          return HOTPLUG_HANDLER(machine);
>      }
>