Re: [Qemu-devel] [PATCH-for-4.2 v7 04/10] hw/arm/virt: Add memory hotplug framework

[Igor Mammedov <imammedo@redhat.com>]

On Tue, 16 Jul 2019 16:38:10 +0100
Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> wrote:

> From: Eric Auger <eric.auger@redhat.com>
> 
> This patch adds the memory hot-plug/hot-unplug infrastructure
> in machvirt. The device memory is not yet exposed to the Guest
> either through DT or ACPI and hence both cold/hot plug of memory
> is explicitly disabled for now.
> 
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> Signed-off-by: Kwangwoo Lee <kwangwoo.lee@sk.com>
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>

> ---
>  hw/arm/Kconfig |  2 ++
>  hw/arm/virt.c  | 51 +++++++++++++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 52 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/arm/Kconfig b/hw/arm/Kconfig
> index ab65ecd216..84961c17ab 100644
> --- a/hw/arm/Kconfig
> +++ b/hw/arm/Kconfig
> @@ -20,6 +20,8 @@ config ARM_VIRT
>      select SMBIOS
>      select VIRTIO_MMIO
>      select ACPI_PCI
> +    select MEM_DEVICE
> +    select DIMM
>  
>  config CHEETAH
>      bool
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index d9496c9363..907fb64bb9 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -64,6 +64,8 @@
>  #include "hw/arm/smmuv3.h"
>  #include "hw/acpi/acpi.h"
>  #include "target/arm/internals.h"
> +#include "hw/mem/pc-dimm.h"
> +#include "hw/mem/nvdimm.h"
>  
>  #define DEFINE_VIRT_MACHINE_LATEST(major, minor, latest) \
>      static void virt_##major##_##minor##_class_init(ObjectClass *oc, \
> @@ -1871,6 +1873,40 @@ static const CPUArchIdList *virt_possible_cpu_arch_ids(MachineState *ms)
>      return ms->possible_cpus;
>  }
>  
> +static void virt_memory_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
> +                                 Error **errp)
> +{
> +
> +    /*
> +     * The device memory is not yet exposed to the Guest either through
> +     * DT or ACPI and hence both cold/hot plug of memory is explicitly
> +     * disabled for now.
> +     */
> +    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
> +        error_setg(errp, "memory cold/hot plug is not yet supported");
> +        return;
> +    }
> +
> +    pc_dimm_pre_plug(PC_DIMM(dev), MACHINE(hotplug_dev), NULL, errp);
> +}
> +
> +static void virt_memory_plug(HotplugHandler *hotplug_dev,
> +                             DeviceState *dev, Error **errp)
> +{
> +    VirtMachineState *vms = VIRT_MACHINE(hotplug_dev);
> +
> +    pc_dimm_plug(PC_DIMM(dev), MACHINE(vms), NULL);
> +
> +}
> +
> +static void virt_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
> +                                            DeviceState *dev, Error **errp)
> +{
> +    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
> +        virt_memory_pre_plug(hotplug_dev, dev, errp);
> +    }
> +}
> +
>  static void virt_machine_device_plug_cb(HotplugHandler *hotplug_dev,
>                                          DeviceState *dev, Error **errp)
>  {
> @@ -1882,12 +1918,23 @@ static void virt_machine_device_plug_cb(HotplugHandler *hotplug_dev,
>                                       SYS_BUS_DEVICE(dev));
>          }
>      }
> +    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
> +        virt_memory_plug(hotplug_dev, dev, errp);
> +    }
> +}
> +
> +static void virt_machine_device_unplug_request_cb(HotplugHandler *hotplug_dev,
> +                                          DeviceState *dev, Error **errp)
> +{
> +    error_setg(errp, "device unplug request for unsupported device"
> +               " type: %s", object_get_typename(OBJECT(dev)));
>  }
>  
>  static HotplugHandler *virt_machine_get_hotplug_handler(MachineState *machine,
>                                                          DeviceState *dev)
>  {
> -    if (object_dynamic_cast(OBJECT(dev), TYPE_SYS_BUS_DEVICE)) {
> +    if (object_dynamic_cast(OBJECT(dev), TYPE_SYS_BUS_DEVICE) ||
> +       (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM))) {
>          return HOTPLUG_HANDLER(machine);
>      }
>  
> @@ -1951,7 +1998,9 @@ static void virt_machine_class_init(ObjectClass *oc, void *data)
>      mc->kvm_type = virt_kvm_type;
>      assert(!mc->get_hotplug_handler);
>      mc->get_hotplug_handler = virt_machine_get_hotplug_handler;
> +    hc->pre_plug = virt_machine_device_pre_plug_cb;
>      hc->plug = virt_machine_device_plug_cb;
> +    hc->unplug_request = virt_machine_device_unplug_request_cb;
>      mc->numa_mem_supported = true;
>  }
>