[Qemu-devel] [RFC PATCH 00/11] spapr: option vector re-work and memory unplug support

[Michael Roth]

This series is based on David's ppc-for-2.8 branch, and is also available from:

  https://github.com/mdroth/qemu/commits/spapr-hotplug-event-update

Patches 1-4 address various deficiencies in how we currently handle option
vectors via ibm,client-architecture-support. This is done here in preparation
for a new option vector bit introduced later in this series, as well as a
number of future option vector bits related to other features, but I can
break this out into a separate series if preferred.

Patches 5-8 add support for an updated event format for hotplug events,
which includes a new way to specify a range of DRCs/LMBs to hotplug/unplug
using a starting position and count, which is necessary for memory unplug.
The format for this new event format is still in draft form, but slated
for inclusion in the PAPR/LoPAPR.

Patches 9-11 add support for memory unplug using the new event format.

In addition to kernel 4.8 or later, there are a number of patches required
to enable support on the guest kernel side. I've including the minimum set
of patches in my branch here:

   https://github.com/mdroth/linux/commits/spapr-hotplug-event-update

   *powerpc/pseries: advertise Hot Plug Event support to firmware
   powerpc/pseries: Implement indexed-count hotplug memory remove
   powerpc/pseries: Implement indexed-count hotplug memory add

Note that there is currently an issue that arises when attempting to
offline an LMB that was onlined using a guest kernel's auto-onlining
mechanism, which can prevent full completion of memory unplug requests.
This is being investigated, but for the purposes of testing this can
be worked around currently by disabling auto-onlining in guests via:

  "echo offline >/sys/devices/system/memory/auto_online_blocks"

and instead onlining the blocks manually or via udev.

 docs/specs/ppc-spapr-hotplug.txt |  55 ++++++++++---
 hw/ppc/Makefile.objs             |   2 +-
 hw/ppc/spapr.c                   | 237 
++++++++++++++++++++++++++++++++++++++++++++++++------
 hw/ppc/spapr_drc.c               |  17 ++++
 hw/ppc/spapr_events.c            | 222 
++++++++++++++++++++++++++++++++++++++++-----------
 hw/ppc/spapr_hcall.c             |  70 +++++++---------
 hw/ppc/spapr_ovec.c              | 244 
++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 include/hw/ppc/spapr.h           |  15 +++-
 include/hw/ppc/spapr_ovec.h      |  67 ++++++++++++++++
 9 files changed, 804 insertions(+), 125 deletions(-)