Re: [Qemu-devel] [PATCH] spapr: Don't create ibm, dynamic-reconfiguration-memory w/o DR LMBs

[Bharata B Rao <bharata@linux.vnet.ibm.com>]

On Tue, Jan 19, 2016 at 04:00:25PM +1100, David Gibson wrote:
> On Tue, Jan 19, 2016 at 10:09:21AM +0530, Bharata B Rao wrote:
> > If guest doesn't have any dynamically reconfigurable (DR) logical memory
> > blocks (LMB), then we shouldn't create ibm,dynamic-reconfiguration-memory
> > device tree node.
> > 
> > Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
> > ---
> > This applies against ppc-for-2.6 branch of David Gibson's tree.
> 
> Applied to ppc-for-2.6, thanks.

There is a slight change in memory nodes representation in DT after this fix
that could result in the following behaviour before and after migration.

For a guest with -m 4G -numa node,nodeid=0,mem=2G -numa node,nodeid=1,mem=2G,
the DT under /proc/device-tree changes like this:

Guest started with QEMU w/o this fix
------------------------------------
memory@0
memory@80000000
ibm,dynamic-reconfiguration-memory

Guest migrated to QEMU w/ this fix included
-------------------------------------------
memory@0
memory@80000000
ibm,dynamic-reconfiguration-memory

After next reboot
-----------------
memory@0
memory@80000000

I guess this is ok, but wanted to sound out this change explicitly.

Regards,
Bharata.