Re: [PATCH v2 4/4] hw/loongarch/virt: Enable cpu hotplug feature on virt machine

[Zhao Liu <zhao1.liu@intel.com>]

> > > @@ -1382,8 +1384,40 @@ static void virt_cpu_pre_plug(HotplugHandler *hotplug_dev,
> > >        }
> > >       if (cpu->phy_id == UNSET_PHY_ID) {
> > > -        error_setg(&local_err, "CPU hotplug not supported");
> > > -        goto out;
> > > +        if ((cpu->thread_id < 0) || (cpu->thread_id >= ms->smp.threads)) {
> > > +            error_setg(&local_err,
> > > +                       "Invalid thread-id %u specified, must be in range 1:%u",
> > > +                       cpu->thread_id, ms->smp.threads - 1);
> > > +            goto out;
> > > +        }
> > > +
> > > +        if ((cpu->core_id < 0) || (cpu->core_id >= ms->smp.cores)) {
> > > +            error_setg(&local_err,
> > > +                       "Invalid core-id %u specified, must be in range 1:%u",
> > > +                       cpu->core_id, ms->smp.cores - 1);
> > > +            goto out;
> > > +        }
> > > +
> > > +        if ((cpu->socket_id < 0) || (cpu->socket_id >= ms->smp.sockets)) {
> > > +            error_setg(&local_err,
> > > +                       "Invalid socket-id %u specified, must be in range 1:%u",
> > > +                       cpu->socket_id, ms->smp.sockets - 1);
> > > +            goto out;
> > > +        }
> > > +
> > > +        topo.socket_id = cpu->socket_id;
> > > +        topo.core_id = cpu->core_id;
> > > +        topo.thread_id = cpu->thread_id;
> > > +        arch_id =  virt_get_arch_id_from_topo(ms, &topo);
> > > +        cpu_slot = virt_find_cpu_slot(ms, arch_id, &index);
> > > +        if (CPU(cpu_slot->cpu)) {
> > > +            error_setg(&local_err,
> > > +                       "cpu(id%d=%d:%d:%d) with arch-id %" PRIu64 " exists",
> > > +                       cs->cpu_index, cpu->socket_id, cpu->core_id,
> > > +                       cpu->thread_id, cpu_slot->arch_id);
> > > +            goto out;
> > > +        }
> > > +        cpu->phy_id = arch_id;
> > >       } else {
> > 
> > Here you allow user to specify topology IDs, but "else" still indicates
> > user could use "phy_id" instead of topology IDs, right?
> "else" for cold-plug CPUs which is created with index from [0 -- smp.cpus)
> 
> > 
> > Is it necessary to expose "phy_id" to user?
> We will remove phy_id property and unexpose it to user.
> 

Thanks! The issue lies with the property itself. Even if you try to
support a hotplug scheme based on topology IDs, users can actually use
phy_id for hotplugging. Removing it seems fine.

Regards,
Zhao