Re: [Qemu-devel] [PATCH 28/35] pc: propagate memory hotplug event to ACPI device

[Michael S. Tsirkin]

On Fri, Apr 04, 2014 at 03:36:53PM +0200, Igor Mammedov wrote:
> Notify PIIX4_PM/ICH9LPC device about hotplug event,
> so that it would send SCI to guest notifying about
> newly added memory.
> 
> Signed-off-by: Igor Mammedov <address@hidden>
> ---
>  hw/i386/pc.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index 734c6ee..ee5cf88 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -60,6 +60,8 @@
>  #include "acpi-build.h"
>  #include "hw/mem/dimm.h"
>  #include "trace.h"
> +#include "hw/acpi/piix4.h"
> +#include "hw/i386/ich9.h"
>  
>  /* debug PC/ISA interrupts */
>  //#define DEBUG_IRQ
> @@ -1484,6 +1486,8 @@ void qemu_register_pc_machine(QEMUMachine *m)
>  static void pc_dimm_plug(HotplugHandler *hotplug_dev,
>                           DeviceState *dev, Error **errp)
>  {
> +    Object *acpi_dev;
> +    HotplugHandlerClass *hhc;
>      Error *local_err = NULL;
>      PCMachineState *pcms = PC_MACHINE(hotplug_dev);
>      DimmDevice *dimm = DIMM(dev);
> @@ -1517,10 +1521,19 @@ static void pc_dimm_plug(HotplugHandler *hotplug_dev,
>      }
>      trace_mhp_pc_dimm_assigned_slot(dimm->slot);
>  
> +    acpi_dev = (acpi_dev = piix4_pm_find()) ? acpi_dev : ich9_lpc_find();
> +    if (!acpi_dev) {
> +        error_setg(&local_err,
> +                   "memory hotplug is not enabled: missing acpi device");
> +        return;
> +    }
> +
> +    hhc = HOTPLUG_HANDLER_GET_CLASS(acpi_dev);

How about simply looking for a hotplug handler type device instead?
We aren't likely to have many of these, are we?

>      memory_region_add_subregion(&pcms->hotplug_memory,
>                                  addr - pcms->hotplug_memory_base,
>                                  mr);
>      vmstate_register_ram(mr, dev);
> +    hhc->plug(HOTPLUG_HANDLER(acpi_dev), dev, &local_err);
>  
>  out:
>      error_propagate(errp, local_err);
> -- 
> 1.9.0