Re: [PATCH] hw/arm/Kconfig: no need to enable ACPI_MEMORY_HOTPLUG explicitly

[Ani Sinha]

On Thu, 19 Aug 2021, Ani Sinha wrote:

>
>
> On Thu, 19 Aug 2021, Peter Maydell wrote:
>
> > On Tue, 17 Aug 2021 at 05:45, Ani Sinha <ani@anisinha.ca> wrote:
> > >
> > > ping ...
> >
> > You didn't cc any of the ACPI maintainers; I have done so.
> >
>
> oops! my bad. I used checkpatch and did not verify if Igor/Michael was
> cc'd.
>
> > Is it intended that ACPI_HW_REDUCED must always imply
> > ACPI_MEMORY_HOTPLUG, or is it just a coincidence that the
> > virt board happens to want both, and so we select both ?
> >
>
> From a purely code inspection point of view, I noticed that
> generic_event_device.c depends on CONFIG_ACPI_HW_REDUCED. The GED does use
> memory hotplug apis - for example acpi_ged_device_plug_cb() uses
> acpi_memory_plug_cb() etc.
>
> Hence, as it stands today, CONFIG_ACPI_HW_REDUCED will need to select ACPI
> memory hotplug. Unless we remove the GED device's dependence on
> ACPI_HW_REDUCED that is. I cannot comment whether that would be wise or if
> we should reorg the code in some other way.

The other question we should ask is whether arm platform requires
ACPI_MEMORY_HOTPLUG independent of ACPI_HW_REDUCED/GED device? If that is
the case, then maybe we should keep that config option as is.
Maybe @qemu-arm can answer that?

>
> > > On Thu, 12 Aug 2021, Ani Sinha wrote:
> > >
> > > > ACPI_MEMORY_HOTPLUG is implicitly turned on when ACPI_HW_REDUCED is 
> > > > selected.
> > > > ACPI_HW_REDUCED is already enabled. No need to turn on 
> > > > ACPI_MEMORY_HOTPLUG
> > > > explicitly. This is a minor cleanup.
> > > >
> > > > Signed-off-by: Ani Sinha <ani@anisinha.ca>
> > > > ---
> > > >  hw/arm/Kconfig | 1 -
> > > >  1 file changed, 1 deletion(-)
> > > >
> > > > diff --git a/hw/arm/Kconfig b/hw/arm/Kconfig
> > > > index 4ba0aca067..38cf9f44e2 100644
> > > > --- a/hw/arm/Kconfig
> > > > +++ b/hw/arm/Kconfig
> > > > @@ -25,7 +25,6 @@ config ARM_VIRT
> > > >      select ACPI_PCI
> > > >      select MEM_DEVICE
> > > >      select DIMM
> > > > -    select ACPI_MEMORY_HOTPLUG
> > > >      select ACPI_HW_REDUCED
> > > >      select ACPI_NVDIMM
> > > >      select ACPI_APEI
> > > > --
> > > > 2.25.1
> > > >
> > > >
> >
> >
> > -- PMM
> >
>