Re: [PATCH v1 0/4] Initialize nr_cores and nr_threads early and related clearup

[David Hildenbrand <david@redhat.com>]

On 22.11.24 03:40, Xiaoyao Li wrote:
> On 11/22/2024 2:52 AM, Paolo Bonzini wrote:
>> On 11/21/24 17:24, Xiaoyao Li wrote:
>>>> Could it go into cpu_common_initfn()?
>>>
>>> It can, I think.
>>>
>>> I'll move them into cpu_common_initfn() in v2 to avoid touching all
>>> the ARCHes.
>>
>> It does look better than the alternative of duplicating code.
>>
>> On the other hand qemu_init_vcpu is already duplicated and I'm not sure
>> I like relying on qdev_get_machine() inside the instance_init function...
> 

Good point.

> I had the same concern.
> 
> But it seems all the ARCHes should create MACHINE before VCPUs. So it
> seems OK to qdev_get_machine() inside the instance_init function. But
> I'm not sure if there is any case to create VCPU standalone.

There are, for example on s390x in create_cpu_model_list(). I recall 
there are ways to start QEMU without any machine and trigger that code. 
(or maybe this was just for the test environment with a special test 
machine ...)

> 
> I think we can check if qdev_get_machine() gets a valid result. If not,
> fall back to assign nr_cores and nr_threads to 1.

That sounds reasonable to me.

-- 
Cheers,

David / dhildenb