Re: [PATCH] cpu hotplug issue

Jan Kiszka
2011-07-21T12:22:18Z

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
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

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