Re: [Qemu-devel] [PATCH 10/16] dimm: add busy slot check and slot auto-allocation

[Paolo Bonzini]

Il 23/07/2013 18:23, Igor Mammedov ha scritto:
> - if slot property is not specified on -device/device_add command,
> treat default value as request for assigning DimmDevice to
> the first free slot.

Even with "-m" instead of "-numa mem", I think this is problematic
because we still need to separate the host and guest parts of the DIMM
device.  "-numa mem" (or the QMP command that Wanlong added) will be
necessary to allocate memory on the host side before adding a DIMM.

So slots will have three states: free (created with "-m"), allocated (a
free slot moves to this state with "-numa mem...,populated=no" when
migrating, or with the QMP command for regular hotplug), populated (an
allocated slot moves to this state with "-device dimm").

You would be able to plug a DIMM only into an allocated slot, and the
size will be specified on the slot rather than the DIMM device.

In general, I don't think free slots should be managed by the DimmBus,
and host vs. guest separation should be there even if we accept your
"-m" extension (doesn't look bad at all, I must say).

Paolo