Re: [PATCH 2/2] numa: properly check if numa is supported

[Tao Xu <tao3.xu@intel.com>]

On 12/13/2019 5:12 PM, Igor Mammedov wrote:
> On Fri, 13 Dec 2019 09:33:10 +0800
> Tao Xu <tao3.xu@intel.com> wrote:
> 
>> On 12/12/2019 8:48 PM, Igor Mammedov wrote:
>>> Commit aa57020774b, by mistake used MachineClass::numa_mem_supported
>>> to check if NUMA is supported by machine and also as unrelated change
>>> set it to true for sbsa-ref board.
>>>
>>> Luckily change didn't break machines that support NUMA, as the field
>>> is set to true for them.
>>>
>>> But the field is not intended for checking if NUMA is supported and
>>> will be flipped to false within this release for new machine types.
>>>
>>> Fix it:
>>>    - by using previously used condition
>>>         !mc->cpu_index_to_instance_props || !mc->get_default_cpu_node_id
>>>      the first time and then use MachineState::numa_state down the road
>>>      to check if NUMA is supported
>>>    - dropping stray sbsa-ref chunk
>>>
>>> Fixes: aa57020774b690a22be72453b8e91c9b5a68c516
>>> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
>>> ---
>>> CC: Radoslaw Biernacki <radoslaw.biernacki@linaro.org>
>>> CC: Peter Maydell <peter.maydell@linaro.org>
>>> CC: Leif Lindholm <leif.lindholm@linaro.org>
>>> CC: qemu-arm@nongnu.org
>>> CC: qemu-stable@nongnu.org
>>>
>>>
>>>    hw/arm/sbsa-ref.c | 1 -
>>>    hw/core/machine.c | 4 ++--
>>>    2 files changed, 2 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/hw/arm/sbsa-ref.c b/hw/arm/sbsa-ref.c
>>> index 27046cc..c6261d4 100644
>>> --- a/hw/arm/sbsa-ref.c
>>> +++ b/hw/arm/sbsa-ref.c
>>> @@ -791,7 +791,6 @@ static void sbsa_ref_class_init(ObjectClass *oc, void *data)
>>>        mc->possible_cpu_arch_ids = sbsa_ref_possible_cpu_arch_ids;
>>>        mc->cpu_index_to_instance_props = sbsa_ref_cpu_index_to_props;
>>>        mc->get_default_cpu_node_id = sbsa_ref_get_default_cpu_node_id;
>>> -    mc->numa_mem_supported = true;
>>>    }
>>>    
>>>    static const TypeInfo sbsa_ref_info = {
>>> diff --git a/hw/core/machine.c b/hw/core/machine.c
>>> index 1689ad3..aa63231 100644
>>> --- a/hw/core/machine.c
>>> +++ b/hw/core/machine.c
>>> @@ -958,7 +958,7 @@ static void machine_initfn(Object *obj)
>>>                                            NULL);
>>>        }
>>>    
>>> -    if (mc->numa_mem_supported) {
>>> +    if (mc->cpu_index_to_instance_props && mc->get_default_cpu_node_id) {
>>>            ms->numa_state = g_new0(NumaState, 1);
>>>        }
>>
>> I am wondering if @numa_mem_supported is unused here, it is unused for
>> QEMU, because the only usage of @numa_mem_supported is to initialize
>> @numa_state. Or there is other usage? So should it be removed from
>> struct MachineClass?
> You are wrong, it's not intended for numa_state initialization,
> read doc comment for it in include/hw/boards.h
> (for full story look at commit cd5ff8333a3)
> 
I understand.