kvm->irq_lock protects too much stuff, but still fail to protect
everything it was design to protect (see ack notifiers call in pic). I
want to make IRQ injection fast path as lockless as possible. This patch
series removes kvm->irq_lock from irq injection path effectively making
interrupt injection to lapic lockless (several kvm_irq_delivery_to_apic()
may run in parallel), but access to lapic was never fully locked in the
first place. VCPU could access lapic in parallel with interrupt injection.
Patches 1/2 changes irq routing data structure to much more efficient one.

v1->v2:
  Drop MSI injection interface (for now).
  Use irq_lock to protect irq routing and ack notifiers.
  Splitting irq routing table changes to two patches (+ comments addressed).
  Drop ioapic/pic lock before calling ack notifiers.
v2->v3
  Drop patch that changes irq_lock to spinlock.
  Use mutex for ioapic lock.
  Do not call ack notifier if there is no GSI mapping.
  Call pic_clear_isr() after PIC state completely changed.

Gleb Natapov (8):
  Do not call ack notifiers on PIC reset.
  Change irq routing table to use gsi indexed array.
  Maintain back mapping from irqchip/pin to gsi.
  Move irq routing data structure to rcu locking
  Move irq ack notifier list to arch independent code.
  Convert irq notifiers lists to RCU locking.
  Move IO APIC to its own lock.
  Drop kvm->irq_lock lock from irq injection path.

 arch/ia64/include/asm/kvm.h      |    1 +
 arch/ia64/include/asm/kvm_host.h |    1 -
 arch/ia64/kvm/kvm-ia64.c         |    9 +--
 arch/x86/include/asm/kvm.h       |    1 +
 arch/x86/include/asm/kvm_host.h  |    1 -
 arch/x86/kvm/i8254.c             |    2 -
 arch/x86/kvm/i8259.c             |   38 +++++-------
 arch/x86/kvm/lapic.c             |    7 +--
 arch/x86/kvm/x86.c               |   12 +---
 include/linux/kvm_host.h         |   18 +++++-
 virt/kvm/eventfd.c               |    2 -
 virt/kvm/ioapic.c                |   80 ++++++++++++++++++------
 virt/kvm/ioapic.h                |    4 +
 virt/kvm/irq_comm.c              |  127 ++++++++++++++++++++------------------
 virt/kvm/kvm_main.c              |    4 +-
 15 files changed, 171 insertions(+), 136 deletions(-)

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