Re: [Qemu-devel] [RFC PATCH v4 00/30] ACPI memory hotplug

[Andreas Färber]

Am 18.12.2012 13:41, schrieb Vasilis Liaskovitis:
> Because dimm layout needs to be configured on machine-boot, all dimm devices
> need to be specified on startup command line (either with populated=on or with
> populated=off). The dimm information is stored in dimm configuration 
> structures.
> 
> After machine startup, dimms are hot-added or removed with normal device_add
> and device_del operations e.g.:
> Hot-add syntax: "device_add dimm,id=mydimm0,bus=membus.0"
> Hot-remove syntax: "device_del dimm,id=mydimm0"

This sounds contradictory: Either all devices need to be specified on
the command line, or they can be hot-added via monitor.

Assuming a fixed layout at startup, I wonder if there is another clever
way to model this... For CPU hotplug Anthony had suggested to have a
fixed set of link<Socket> properties that get set to a CPU socket as
needed. Might a similar strategy work for memory, i.e. a
startup-configured amount of link<DIMM>s on /machine/dimm[n] that point
to a QOM DIMM object or NULL if unpopulated? Hot(un)plug would then
simply work via QMP qom-set command. (CC'ing some people)

Regards,
Andreas

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