Re: [Qemu-devel] [RFC v3 07/15] hw/arm/virt: Add memory hotplug framework

[Auger Eric <eric.auger@redhat.com>]

Hi David,

On 07/03/2018 08:44 PM, David Hildenbrand wrote:
> On 03.07.2018 09:19, Eric Auger wrote:
>> From: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
>>
>> This patch adds the the memory hot-plug/hot-unplug infrastructure
>> in machvirt.
>>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
>> Signed-off-by: Kwangwoo Lee <kwangwoo.lee@sk.com>
>>
>> ---
>>
>> v1 -> v2:
>> - s/virt_dimm_plug|unplug/virt_memory_plug|unplug
>> - s/pc_dimm_memory_plug/pc_dimm_plug
>> - reworded title and commit message
>> - added pre_plug cb
>> - don't handle get_memory_region failure anymore
>> ---
>>  default-configs/arm-softmmu.mak |  2 ++
>>  hw/arm/virt.c                   | 68 ++++++++++++++++++++++++++++++++++++++++-
>>  2 files changed, 69 insertions(+), 1 deletion(-)
>>
>> diff --git a/default-configs/arm-softmmu.mak b/default-configs/arm-softmmu.mak
>> index 834d45c..28fe8f3 100644
>> --- a/default-configs/arm-softmmu.mak
>> +++ b/default-configs/arm-softmmu.mak
>> @@ -152,3 +152,5 @@ CONFIG_PCI_DESIGNWARE=y
>>  CONFIG_STRONGARM=y
>>  CONFIG_HIGHBANK=y
>>  CONFIG_MUSICPAL=y
>> +CONFIG_MEM_HOTPLUG=y
>> +
>> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
>> index 6fefb78..7190962 100644
>> --- a/hw/arm/virt.c
>> +++ b/hw/arm/virt.c
>> @@ -60,6 +60,8 @@
>>  #include "standard-headers/linux/input.h"
>>  #include "hw/arm/smmuv3.h"
>>  #include "hw/acpi/acpi.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, \
>> @@ -1785,6 +1787,53 @@ 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)
>> +{
>> +    const bool is_nvdimm = object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM);
>> +
>> +    if (is_nvdimm) {
>> +        error_setg(errp, "nvdimm is not yet supported");
>> +        return;
>> +    }
> 
> You mention that actual hotplug is not supported, only coldplug.
> Wouldn't this be the right place to check for that? (only skimmed over
> your patches, how do you handle that?)
At the moment I don't check it. I did not look yet at ways to
discriminate both cases.

Thanks

Eric
> 
>