Re: [PATCH] cpu hotplug issue

Gleb Natapov
2011-07-21T12:26:04Z

On Thu, Jul 21, 2011 at 02:22:07PM +0200, Jan Kiszka wrote:
> On 2011-07-21 13:06, Vasilis Liaskovitis wrote:
> > More precisely: To enable cpu-hotplug at each bisect stage, I apply
> > this patch derived from:
> > http://lists.gnu.org/archive/html/qemu-devel/2010-08/msg00850.html
> >
> > diff --git a/hw/qdev.c b/hw/qdev.c
> > index 1aa1ea0..aed48ce 100644
> > --- a/hw/qdev.c
> > +++ b/hw/qdev.c
> > @@ -327,6 +327,7 @@ BusState *sysbus_get_default(void)
> > if (!main_system_bus) {
> > main_system_bus = qbus_create(&system_bus_info, NULL,
> > "main-system-bus");
> > + main_system_bus->allow_hotplug = 1;
>
> BTW, this reminds me why "fixing" CPU hotplug won't help a lot. We
I do not see relation between qdev not allowing cpu hotplug bug and cpu been
created with incorrect state bug. Fixing of former will not magically
make later disappear. Both should be solved.

> finally need to _design_ the infrastructure required for CPU hotplugging
> and stop hacking away reasonable bits that do not fit in the current
> simplistic CPU interface model.
>
> The questions are:
> - How should the CPU-APIC-chipset topology should look like in an
> ideal (qdev reworked or qdev replaced with X) world should like?
> - How can we make useful step in that direction given the current
> mechanisms (e.g. a hotpluggable APIC bus created by the chipset)?
>
> Jan
>
> --
> Siemens AG, Corporate Technology, CT T DE IT 1
> Corporate Competence Center Embedded Linux

--
Gleb.