Re: [Qemu-devel] [PATCH v3 0/4] s390: Support for Hotplug of Standby Memory

[Christian Borntraeger]

On 07/05/14 20:05, Matthew Rosato wrote:
> This patchset adds support in s390 for a pool of standby memory,
> which can be set online/offline by the guest (ie, via chmem).
> New options, maxmem and slots, are added to the QEMU command line
> memory parameter to specify the total amount of memory available 
> to the guest as well as the number of memory slots available.
> As part of this work, additional results are provided for the 
> Read SCP Information SCLP, and new implentation is added for the 
> Read Storage Element Information, Attach Storage Element, 
> Assign Storage and Unassign Storage SCLPs, which enables the s390 
> guest to manipulate the standby memory pool.
> 
> This patchset is based on work originally done by Jeng-Fang (Nick)
> Wang.
> 
> Changes for v3:
>  * Remove some patches shared with ACPI memory hotplug that are now
>    applied to master
>  * Fix in sclp.h to avoid compiler error for s390x-linux-user mode
>  * Fix in s390-virtio-ccw.c to avoid checking the value of 
>    mhd->increment_size before it's been set with a meaningful
>    value. 
>  * Add MAX_STORAGE_INCREMENTS
> 
> Changes for v2:
>  * Removed the patch that introduced the standby-mem operand and 
>    instead included Igor Mammedov's patches that add the mem-opts 
>    'maxmem' and 'slots', with a slight modification due to the removal 
>    of qemu_opts_create_nofail.
>  * Patch 3 was inserted to add a new qom object that encapsulate variables 
>    used by s390 memory hotplug.  Patches 4 and 5 adjusted to use this 
>    object.
>  * Added additional code comments and other minor changes per Alexander 
>    Graf's comments
> 
> Igor Mammedov (1):
>   vl.c: extend -m option to support options for memory hotplug
> 
> Matthew Rosato (3):
>   sclp-s390: Add device to manage s390 memory hotplug
>   virtio-ccw: Include standby memory when calculating storage increment
>   sclp-s390: Add memory hotplug SCLPs
> 
>  hw/s390x/s390-virtio-ccw.c |   44 +++++--
>  hw/s390x/sclp.c            |  277 
> ++++++++++++++++++++++++++++++++++++++++++--
>  include/hw/boards.h        |    2 +
>  include/hw/s390x/sclp.h    |   19 +++
>  qemu-options.hx            |    9 +-
>  target-s390x/cpu.h         |   18 +++
>  target-s390x/kvm.c         |    5 +
>  vl.c                       |   51 ++++++++
>  8 files changed, 407 insertions(+), 18 deletions(-)
> 

I think the patch set is shaping up quite well. two things:
1. I had some small comments to the patches, please have a look
2. Igor, what are your plans on pushing the first patch (and implement hotplug 
for x86) Could you push patch1 independently from the other patches?