KVM: x86/mmu: Move restore_acc_track_spte() to spte.h

restore_acc_track_spte() is pure SPTE bit manipulation, making it a good
fit for spte.h. And now that the WARN_ON_ONCE() calls have been removed,
there isn't any good reason to not inline it.

This move also prepares for a follow-up commit that will need to call
restore_acc_track_spte() from spte.c

No functional change intended.
Reviewed-by: Ben Gardon <bgardon@google.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220119230739.2234394-11-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu/mmu.c

@@ -645,20 +645,6 @@ static u64 mmu_spte_get_lockless(u64 *sptep)
 	return __get_spte_lockless(sptep);
 }
 
-/* Restore an acc-track PTE back to a regular PTE */
-static u64 restore_acc_track_spte(u64 spte)
-{
-	u64 saved_bits = (spte >> SHADOW_ACC_TRACK_SAVED_BITS_SHIFT)
-			 & SHADOW_ACC_TRACK_SAVED_BITS_MASK;
-
-	spte &= ~shadow_acc_track_mask;
-	spte &= ~(SHADOW_ACC_TRACK_SAVED_BITS_MASK <<
-		  SHADOW_ACC_TRACK_SAVED_BITS_SHIFT);
-	spte |= saved_bits;
-
-	return spte;
-}
-
 /* Returns the Accessed status of the PTE and resets it at the same time. */
 static bool mmu_spte_age(u64 *sptep)
 {

arch/x86/kvm/mmu/spte.h

@@ -418,6 +418,21 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
 u64 make_nonleaf_spte(u64 *child_pt, bool ad_disabled);
 u64 make_mmio_spte(struct kvm_vcpu *vcpu, u64 gfn, unsigned int access);
 u64 mark_spte_for_access_track(u64 spte);
+
+/* Restore an acc-track PTE back to a regular PTE */
+static inline u64 restore_acc_track_spte(u64 spte)
+{
+	u64 saved_bits = (spte >> SHADOW_ACC_TRACK_SAVED_BITS_SHIFT)
+			 & SHADOW_ACC_TRACK_SAVED_BITS_MASK;
+
+	spte &= ~shadow_acc_track_mask;
+	spte &= ~(SHADOW_ACC_TRACK_SAVED_BITS_MASK <<
+		  SHADOW_ACC_TRACK_SAVED_BITS_SHIFT);
+	spte |= saved_bits;
+
+	return spte;
+}
+
 u64 kvm_mmu_changed_pte_notifier_make_spte(u64 old_spte, kvm_pfn_t new_pfn);
 
 void kvm_mmu_reset_all_pte_masks(void);