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

[David Hildenbrand]

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