Re: [PATCH v2 04/15] tests: acpi: q35: test for x2APIC entries in SRAT

[Thomas Huth <thuth@redhat.com>]

On 20/10/2021 10.53, Igor Mammedov wrote:
> On Wed, 20 Oct 2021 04:18:07 -0400
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
> 
>> On Wed, Oct 20, 2021 at 10:16:07AM +0200, Igor Mammedov wrote:
>>> On Tue, 19 Oct 2021 07:44:38 -0400
>>> "Michael S. Tsirkin" <mst@redhat.com> wrote:
>>>    
>>>> On Tue, Oct 19, 2021 at 01:36:24PM +0200, Igor Mammedov wrote:
>>>>> On Tue, 19 Oct 2021 06:23:40 -0400
>>>>> "Michael S. Tsirkin" <mst@redhat.com> wrote:
>>>>>      
>>>>>> On Tue, Oct 19, 2021 at 11:48:25AM +0200, Igor Mammedov wrote:
>>>>>>> On Mon, 18 Oct 2021 17:31:33 -0400
>>>>>>> "Michael S. Tsirkin" <mst@redhat.com> wrote:
>>>>>>>        
>>>>>>>> On Thu, Sep 02, 2021 at 07:35:40AM -0400, Igor Mammedov wrote:
>>>>>>>>> Set -smp 1,maxcpus=288 to test for ACPI code that
>>>>>>>>> deal with CPUs with large APIC ID (>255).
>>>>>>>>>
>>>>>>>>> PS:
>>>>>>>>> Test requires KVM and in-kernel irqchip support,
>>>>>>>>> so skip test if KVM is not available.
>>>>>>>>>
>>>>>>>>> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
>>>>>>>>> ---
>>>>>>>>> v3:
>>>>>>>>>    - add dedicated test instead of abusing 'numamem' one
>>>>>>>>>    - add 'kvm' prefix to the test name
>>>>>>>>>        ("Michael S. Tsirkin" <mst@redhat.com>)
>>>>>>>>> v2:
>>>>>>>>>    - switch to qtest_has_accel() API
>>>>>>>>>
>>>>>>>>> CC: thuth@redhat.com
>>>>>>>>> CC: lvivier@redhat.com
>>>>>>>>> ---
>>>>>>>>>   tests/qtest/bios-tables-test.c | 17 +++++++++++++++++
>>>>>>>>>   1 file changed, 17 insertions(+)
>>>>>>>>>
>>>>>>>>> diff --git a/tests/qtest/bios-tables-test.c b/tests/qtest/bios-tables-test.c
>>>>>>>>> index 51d3a4e239..1f6779da87 100644
>>>>>>>>> --- a/tests/qtest/bios-tables-test.c
>>>>>>>>> +++ b/tests/qtest/bios-tables-test.c
>>>>>>>>> @@ -1033,6 +1033,19 @@ static void test_acpi_q35_tcg_numamem(void)
>>>>>>>>>       free_test_data(&data);
>>>>>>>>>   }
>>>>>>>>>   
>>>>>>>>> +static void test_acpi_q35_kvm_xapic(void)
>>>>>>>>> +{
>>>>>>>>> +    test_data data;
>>>>>>>>> +
>>>>>>>>> +    memset(&data, 0, sizeof(data));
>>>>>>>>> +    data.machine = MACHINE_Q35;
>>>>>>>>> +    data.variant = ".xapic";
>>>>>>>>> +    test_acpi_one(" -object memory-backend-ram,id=ram0,size=128M"
>>>>>>>>> +                  " -numa node -numa node,memdev=ram0"
>>>>>>>>> +                  " -machine kernel-irqchip=on -smp 1,maxcpus=288", &data);
>>>>>>>>> +    free_test_data(&data);
>>>>>>>>> +}
>>>>>>>>> +
>>>>>>>>>   static void test_acpi_q35_tcg_nosmm(void)
>>>>>>>>>   {
>>>>>>>>>       test_data data;
>>>>>>>>
>>>>>>>>
>>>>>>>> This causes an annoying message each time I run it:
>>>>>>>>
>>>>>>>> qemu-system-x86_64: -accel kvm: warning: Number of hotpluggable cpus requested (288) exceeds the recommended cpus supported by KVM (240)
>>>>>>>>
>>>>>>>> what gives?
>>>>>>>
>>>>>>> it depends on kernel, see kvm_recommended_vcpus().
>>>>>>>
>>>>>>> We probably should bump it on upstream kernel side
>>>>>>> (it's much more than that in RHEL8).
>>>>>>>
>>>>>>> Is there anything that prevents bumping upstream kernel limits?
>>>>>>
>>>>>> what should we do with the annoying warning though?
>>>>>
>>>>> I'd leave it alone.
>>>>> What do you suggest?
>>>>>       
>>>>
>>>> reduce the value so a typical system does not trigger it?
>>>
>>> it won't work, test needs as minimum 255 vcpus to trigger X2APIC logic
>>> and 288 value additionally tests max limits
>>
>> Add a flag to disable the warning while running this specific test?
> 
> if it were qtest accel, it would be trivial but
> I'm not aware of something similar for tcg/kvm mode.
> Do you suggest to add to QEMU a CLI option for that?

I think you can still use qtest_enabled(), even if -accel kvm has been 
specified on top?

  Thomas