[RFC PATCH V4] Implement 3-level event channel ABI in Xen

[Wei Liu <wei.liu2@citrix.com>]

The first patch is Ian's fix for ARM xen_ulong_t, which is not in tree at the
moment.

The Linux side patches are working. As any change in the hypervisor side causes
change in kernel side, I don't bother posting them at this point.

Changes since V3:
* Dedicated EVTCHNOP for extended ABI query
* Dedicated EVTCHNOP for 3-level ABI registration
* 3-level ABI is registered in two phases:
  * register the bitmaps
  * register per-cpu L2 selector
* libxl: evtchn_extended -> evtchn_extended_allowed

Changes since V2:
* new interface to register extended event channel ABI
* use vmap to simplify mapping
* replace MAX_EVTCHNS macro with inline function
* libxl: evtchn_l3 -> evtchn_extended

The most notable bit of this series is the interface change. In order to cope
with future ABIs, the interface is renamed to EVTCHNOP_register_extended. It
also provides supported ABI query, so that we can remove unused ABI in the
future.

The semantic meaning of EVTCHNOP_register_extended changes a bit. The `level'
in parameter now changes to `cmd', which means we should go down to specific
ABI routines. ABI-specific structures are still embedded in the union.

Changes since V1:
* move all evtchn related macros / struct definitions to event.h
* only allow 3-level evtchn for Dom0 and driver domains
* add evtchn_l3 flag in libxl

Diffstat:
 docs/man/xl.cfg.pod.5              |   10 +
 tools/libxl/libxl_create.c         |    4 +
 tools/libxl/libxl_types.idl        |    1 +
 tools/libxl/xl_cmdimpl.c           |    3 +
 xen/arch/arm/domain.c              |    1 +
 xen/arch/x86/domain.c              |    1 +
 xen/arch/x86/irq.c                 |    7 +-
 xen/common/domain.c                |    3 +
 xen/common/domctl.c                |    6 +-
 xen/common/event_channel.c         |  458 +++++++++++++++++++++++++++++++++---
 xen/common/keyhandler.c            |    6 +-
 xen/common/schedule.c              |    4 +-
 xen/include/asm-arm/config.h       |    4 +
 xen/include/asm-x86/config.h       |    7 +-
 xen/include/public/domctl.h        |    3 +
 xen/include/public/event_channel.h |   48 ++++
 xen/include/public/xen.h           |   35 ++-
 xen/include/xen/event.h            |   82 ++++++-
 xen/include/xen/sched.h            |   65 ++---
 xen/xsm/flask/hooks.c              |    1 +
 20 files changed, 641 insertions(+), 108 deletions(-)