KVM: x86/mmu: Consolidate "is MMIO SPTE" code

Replace the open-coded "is MMIO SPTE" checks in the MMU warnings
related to software-based access/dirty tracking to make the code
slightly more self-documenting.

No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu.c

@@ -310,6 +310,11 @@ void kvm_mmu_set_mmio_spte_mask(u64 mmio_mask, u64 mmio_value, u64 access_mask)
 }
 EXPORT_SYMBOL_GPL(kvm_mmu_set_mmio_spte_mask);
 
+static bool is_mmio_spte(u64 spte)
+{
+	return (spte & shadow_mmio_mask) == shadow_mmio_value;
+}
+
 static inline bool sp_ad_disabled(struct kvm_mmu_page *sp)
 {
 	return sp->role.ad_disabled;
@@ -317,19 +322,19 @@ static inline bool sp_ad_disabled(struct kvm_mmu_page *sp)
 
 static inline bool spte_ad_enabled(u64 spte)
 {
-	MMU_WARN_ON((spte & shadow_mmio_mask) == shadow_mmio_value);
+	MMU_WARN_ON(is_mmio_spte(spte));
 	return !(spte & shadow_acc_track_value);
 }
 
 static inline u64 spte_shadow_accessed_mask(u64 spte)
 {
-	MMU_WARN_ON((spte & shadow_mmio_mask) == shadow_mmio_value);
+	MMU_WARN_ON(is_mmio_spte(spte));
 	return spte_ad_enabled(spte) ? shadow_accessed_mask : 0;
 }
 
 static inline u64 spte_shadow_dirty_mask(u64 spte)
 {
-	MMU_WARN_ON((spte & shadow_mmio_mask) == shadow_mmio_value);
+	MMU_WARN_ON(is_mmio_spte(spte));
 	return spte_ad_enabled(spte) ? shadow_dirty_mask : 0;
 }
 
@@ -404,11 +409,6 @@ static void mark_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, u64 gfn,
 	mmu_spte_set(sptep, mask);
 }
 
-static bool is_mmio_spte(u64 spte)
-{
-	return (spte & shadow_mmio_mask) == shadow_mmio_value;
-}
-
 static gfn_t get_mmio_spte_gfn(u64 spte)
 {
 	u64 gpa = spte & shadow_nonpresent_or_rsvd_lower_gfn_mask;