Re: [Qemu-devel] [PATCH v1 6/8] spapr: handle pc-dimm unplug via hotplug handler chain

[Igor Mammedov <imammedo@redhat.com>]

On Thu,  7 Jun 2018 18:52:16 +0200
David Hildenbrand <david@redhat.com> wrote:

> Let's handle it via hotplug_handler_unplug(). E.g. necessary to hotplug/
> unplug memory devices (which a pc-dimm is) later.
Perhaps something like following would be better:

Factor out memory unplug into separate function from spapr_lmb_release().
Then use generic hotplug_handler_unplug() to trigger memory unplug,
which would call spapr_machine_device_unplug() -> spapr_memory_unplug()
in the end .
This way unplug operation is not buried in lmb internals and located
in the same place like in other targets, following similar
logic/call chain across targets.


> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  hw/ppc/spapr.c | 18 +++++++++++++++---
>  1 file changed, 15 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index bcb72d9fa7..0a8a3455d6 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -3298,7 +3298,8 @@ static sPAPRDIMMState *spapr_recover_pending_dimm_state(sPAPRMachineState *ms,
>  /* Callback to be called during DRC release. */
>  void spapr_lmb_release(DeviceState *dev)
>  {
> -    sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_hotplug_handler(dev));
> +    HotplugHandler *hotplug_ctrl = qdev_get_hotplug_handler(dev);
> +    sPAPRMachineState *spapr = SPAPR_MACHINE(hotplug_ctrl);
>      sPAPRDIMMState *ds = spapr_pending_dimm_unplugs_find(spapr, PC_DIMM(dev));
>  
>      /* This information will get lost if a migration occurs
> @@ -3316,9 +3317,17 @@ void spapr_lmb_release(DeviceState *dev)
>  
>      /*
>       * Now that all the LMBs have been removed by the guest, call the
> -     * pc-dimm unplug handler to cleanup up the pc-dimm device.
> +     * unplug handler chain. This can never fail.
>       */
> -    pc_dimm_memory_unplug(dev, MACHINE(spapr));
> +    hotplug_handler_unplug(hotplug_ctrl, dev, &error_abort);
> +}
> +
> +static void spapr_memory_unplug(HotplugHandler *hotplug_dev, DeviceState *dev)
> +{
> +    sPAPRMachineState *spapr = SPAPR_MACHINE(hotplug_dev);
> +    sPAPRDIMMState *ds = spapr_pending_dimm_unplugs_find(spapr, PC_DIMM(dev));
> +
> +    pc_dimm_memory_unplug(dev, MACHINE(hotplug_dev));
>      object_unparent(OBJECT(dev));
>      spapr_pending_dimm_unplugs_remove(spapr, ds);
>  }
> @@ -3589,6 +3598,9 @@ static void spapr_machine_device_plug(HotplugHandler *hotplug_dev,
>  static void spapr_machine_device_unplug(HotplugHandler *hotplug_dev,
>                                          DeviceState *dev, Error **errp)
>  {
> +    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
> +        spapr_memory_unplug(hotplug_dev, dev);
> +    }
>  }
>  
>  static void spapr_machine_device_unplug_request(HotplugHandler *hotplug_dev,