Re: [Qemu-devel] [RFC] QMP: add query-hotpluggable-cpus

[Markus Armbruster]

Igor Mammedov <address@hidden> writes:

> it will allow mgmt to query present and possible to hotplug CPUs
> it is required from a target platform that wish to support
> command to set board specific MachineClass.possible_cpus() hook,
> which will return a list of possible CPUs with options
> that would be needed for hotplugging possible CPUs.
>
> For RFC there are:
>    'arch_id': 'int' - mandatory unique CPU number,
>                       for x86 it's APIC ID for ARM it's MPIDR
>    'type': 'str' - CPU object type for usage with device_add
>
> and a set of optional fields that would allows mgmt tools
> to know at what granularity and where a new CPU could be
> hotplugged;
> [node],[socket],[core],[thread]
> Hopefully that should cover needs for CPU hotplug porposes for
> magor targets and we can extend structure in future adding
> more fields if it will be needed.
>
> also for present CPUs there is a 'cpu_link' field which
> would allow mgmt inspect whatever object/abstraction
> the target platform considers as CPU object.
>
> For RFC purposes implements only for x86 target so far.

Adding ad hoc queries as we go won't scale.  Could this be solved by a
generic introspection interface?