KVM: VMX: Register a new IPI for posted interrupt

Posted Interrupt feature requires a special IPI to deliver posted interrupt
to guest. And it should has a high priority so the interrupt will not be
blocked by others.
Normally, the posted interrupt will be consumed by vcpu if target vcpu is
running and transparent to OS. But in some cases, the interrupt will arrive
when target vcpu is scheduled out. And host will see it. So we need to
register a dump handler to handle it.

Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index c1d01e6..7272089 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -1166,6 +1166,11 @@
 apicinterrupt X86_PLATFORM_IPI_VECTOR \
 	x86_platform_ipi smp_x86_platform_ipi
 
+#ifdef CONFIG_HAVE_KVM
+apicinterrupt POSTED_INTR_VECTOR \
+	kvm_posted_intr_ipi smp_kvm_posted_intr_ipi
+#endif
+
 apicinterrupt THRESHOLD_APIC_VECTOR \
 	threshold_interrupt smp_threshold_interrupt
 apicinterrupt THERMAL_APIC_VECTOR \