This patch changes the PIC interrupts delivery. Now it is only delivered
to vcpu0 when either condition is met (on vcpu0):
  1. local APIC is hardware disabled
  2. LVT0 is unmasked and configured to delivery mode ExtInt

It fixes the 2x faster wall clock on x86_64 and SMP i386 Linux guests
Signed-off-by: NEddie (Yaozu) Dong <eddie.dong@intel.com>
Signed-off-by: NQing He <qing.he@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

APIC timer IRQ is set every time when a certain period
expires at host time, but the guest may be descheduled
at that time and thus the irq be overwritten by later fire.
This patch keep track of firing irq numbers and decrease
only when the IRQ is injected to guest or buffered in
APIC.
Signed-off-by: NYaozu (Eddie) Dong <Eddie.Dong@intel.com>
Signed-off-by: NQing He <qing.he@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

By sleeping in the kernel when hlt is executed, we simplify the in-kernel
guest interrupt path considerably.
Signed-off-by: NGregory Haskins <ghaskins@novell.com>
Signed-off-by: NYaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

This allows in-kernel host-side device drivers to raise guest interrupts
without going to userspace.

[avi: fix level-triggered interrupt redelivery on eoi]
[avi: add missing #include]
[avi: avoid redelivery of edge-triggered interrupt]
[avi: implement polarity]
[avi: don't deliver edge-triggered interrupts when unmasking]
[avi: fix host oops on invalid guest access]
Signed-off-by: NYaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Because lightweight exits (exits which don't involve userspace) are many
times faster than heavyweight exits, it makes sense to emulate high usage
devices in the kernel.  The local APIC is one such device, especially for
Windows and for SMP, so we add an APIC model to kvm.

It also allows in-kernel host-side drivers to inject interrupts without
going through userspace.

[compile fix on i386 from Jindrich Makovicka]
Signed-off-by: NYaozu (Eddie) Dong <Eddie.Dong@intel.com>
Signed-off-by: NQing He <qing.he@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

Signed-off-by: NYaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>