[Qemu-devel] [PATCH v1 0/8] MemoryDevice: introduce and use ResourceHandler

[David Hildenbrand <david@redhat.com>]

Hotplug handlers usually have the following tasks:
1. Allocate some resources for a new device
2. Make the new device visible for the guest
3. Notify the guest about the new device

Hotplug handlers have right now one limitation: They handle their own
context and only care about resources they manage.

We can have devices that need certain other resources that are e.g.
system resources managed by the machine. We need a clean way to assign
these resources (without violating layers as brought up by Igor).

One example is virtio-mem/virtio-pmem. Both device types need to be
assigned some region in guest physical address space. This device memory
belongs to the machine and is managed by it. However, virito devices are
hotplugged using the hotplug handler their proxy device implements. So we
could trigger e.g. a PCI hotplug handler for virtio-pci or a CSS/CCW
hotplug handler for virtio-ccw. But definetly not the machine.

So let's generalize the task of "assigning" resources and use it directly
for memory devices. We now have a clean way to support any kind of memory
device - independent of the underlying device type. Right now, only one
resource handler per device can be supported (in addition to the existing
hotplug handler).

You can find more details in patch nr 2.

This work is based on the already queued patch series
    "[PATCH v4 00/11] pc-dimm: factor out MemoryDevice"

David Hildenbrand (8):
  memory-device: always compile support for memory devices for SOFTMMU
  qdev: introduce ResourceHandler as a first-stage hotplug handler
  machine: provide default resource handler
  memory-device: new functions to handle resource assignment
  pc-dimm: implement new memory device functions
  machine: introduce enforce_memory_device_align() and add it for pc
  memory-device: factor out pre-assign into default resource handler
  memory-device: factor out (un)assign into default resource handler

 hw/Makefile.objs               |   2 +-
 hw/core/Makefile.objs          |   1 +
 hw/core/machine.c              |  70 +++++++++++++++++++++++
 hw/core/qdev.c                 |  41 +++++++++++++-
 hw/core/resource-handler.c     |  57 +++++++++++++++++++
 hw/i386/pc.c                   |  31 ++++++-----
 hw/mem/Makefile.objs           |   2 +-
 hw/mem/memory-device.c         | 122 +++++++++++++++++++++++++----------------
 hw/mem/pc-dimm.c               |  53 ++++++++----------
 hw/mem/trace-events            |   4 +-
 hw/ppc/spapr.c                 |   5 +-
 include/hw/boards.h            |  17 ++++++
 include/hw/mem/memory-device.h |  17 ++++--
 include/hw/mem/pc-dimm.h       |   3 +-
 include/hw/resource-handler.h  |  46 ++++++++++++++++
 stubs/Makefile.objs            |   1 -
 stubs/qmp_memory_device.c      |  13 -----
 17 files changed, 364 insertions(+), 121 deletions(-)
 create mode 100644 hw/core/resource-handler.c
 create mode 100644 include/hw/resource-handler.h
 delete mode 100644 stubs/qmp_memory_device.c

-- 
2.14.3