Fix various breakages with INTX/GSI event channel interrupt delivery,
and add a command line option to test it so that it hopefully doesn't
get so broken again.

Karim attempted to rip this out in 2017 but put it back because it's still
necessary with older versions of Xen. This fixes it properly, and makes it
easier to test. cf. https://lkml.org/lkml/2017/4/10/266

David Woodhouse (5):
      xen: Fix event channel callback via INTX/GSI
      xen: Set platform PCI device INTX affinity to CPU0
      x86/xen: Add a no_vector_callback option to test PCI INTX delivery
      x86/xen: Don't register Xen IPIs when they aren't going to be used
      x86/xen: Don't register PV spinlock IPI when it isn't going to be used

 arch/arm/xen/enlighten.c          |  2 +-
 arch/x86/xen/enlighten_hvm.c      | 15 +++++++--
 arch/x86/xen/spinlock.c           |  6 ++--
 drivers/xen/events/events_base.c  | 10 ------
 drivers/xen/platform-pci.c        |  8 ++++-
 drivers/xen/xenbus/xenbus.h       |  1 +
 drivers/xen/xenbus/xenbus_comms.c |  8 -----
 drivers/xen/xenbus/xenbus_probe.c | 68 +++++++++++++++++++++++++++++++--------
 include/xen/xenbus.h              |  2 +-
 9 files changed, 79 insertions(+), 41 deletions(-)