KVM: x86: store IOAPIC-handled vectors in each VCPU

We can reuse the algorithm that computes the EOI exit bitmap to figure
out which vectors are handled by the IOAPIC.  The only difference
between the two is for edge-triggered interrupts other than IRQ8
that have no notifiers active; however, the IOAPIC does not have to
do anything special for these interrupts anyway.

This again limits the interactions between the IOAPIC and the LAPIC,
making it easier to move the former to userspace.

Inspired by a patch from Steve Rutherford.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 5693dd9..4c30fb0 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -869,14 +869,20 @@
 	return vcpu1->arch.apic_arb_prio - vcpu2->arch.apic_arb_prio;
 }
 
+static bool kvm_ioapic_handles_vector(struct kvm_lapic *apic, int vector)
+{
+	return test_bit(vector, (ulong *)apic->vcpu->arch.eoi_exit_bitmap);
+}
+
 static void kvm_ioapic_send_eoi(struct kvm_lapic *apic, int vector)
 {
-	if (kvm_ioapic_handles_vector(apic->vcpu->kvm, vector)) {
+	if (kvm_ioapic_handles_vector(apic, vector)) {
 		int trigger_mode;
 		if (apic_test_vector(vector, apic->regs + APIC_TMR))
 			trigger_mode = IOAPIC_LEVEL_TRIG;
 		else
 			trigger_mode = IOAPIC_EDGE_TRIG;
+
 		kvm_ioapic_update_eoi(apic->vcpu, vector, trigger_mode);
 	}
 }
@@ -1923,7 +1929,7 @@
 	    /* Cache not set: could be safe but we don't bother. */
 	    apic->highest_isr_cache == -1 ||
 	    /* Need EOI to update ioapic. */
-	    kvm_ioapic_handles_vector(vcpu->kvm, apic->highest_isr_cache)) {
+	    kvm_ioapic_handles_vector(apic, apic->highest_isr_cache)) {
 		/*
 		 * PV EOI was disabled by apic_sync_pv_eoi_from_guest
 		 * so we need not do anything here.