[PATCH v4 0/5] Xen INTX/GSI event channel delivery fixes

[David Woodhouse <dwmw2@xxxxxxxxxxxxx>]

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

v2:
 • Add no_vector_callback to Documentation/admin-guide/kernel-parameters.txt
 • Further fixes to conditional smp_ops initialisation in xen_hvm_smp_init()

v3:
 • Rename test option to xen_no_vector_callback

v4:
 • Fix unconditional references to xen_have_vector_callback in Arm build

David Woodhouse (5):
      xen: Fix event channel callback via INTX/GSI
      xen: Set platform PCI device INTX affinity to CPU0
      x86/xen: Add xen_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: Fix xen_hvm_smp_init() when vector callback not available

 Documentation/admin-guide/kernel-parameters.txt |  4 ++
 arch/arm/xen/enlighten.c                        |  2 +-
 arch/x86/xen/enlighten_hvm.c                    | 15 ++++-
 arch/x86/xen/smp_hvm.c                          | 27 ++++++---
 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               | 81 ++++++++++++++++++++-----
 include/xen/xenbus.h                            |  2 +-
 10 files changed, 110 insertions(+), 48 deletions(-)