KVM: Introduce bitmask for apic attention reasons

The patch introduces a bitmap that will hold reasons apic should be
checked during vmexit. This is in a preparation for vp eoi patch
that will add one more check on vmexit. With the bitmap we can do
if(apic_attention) to check everything simultaneously which will
add zero overhead on the fast path.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f624ca7..69e39bc 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -172,6 +172,9 @@
 #define DR7_FIXED_1	0x00000400
 #define DR7_VOLATILE	0xffff23ff
 
+/* apic attention bits */
+#define KVM_APIC_CHECK_VAPIC	0
+
 /*
  * We don't want allocation failures within the mmu code, so we preallocate
  * enough memory for a single page fault in a cache.
@@ -337,6 +340,7 @@
 	u64 efer;
 	u64 apic_base;
 	struct kvm_lapic *apic;    /* kernel irqchip context */
+	unsigned long apic_attention;
 	int32_t apic_arb_prio;
 	int mp_state;
 	int sipi_vector;