KVM: MMU: introduce kvm_mmu_slot_gfn_write_protect

Split rmap_write_protect() and introduce the function to abstract the write
protection based on the slot

This function will be used in the later patch
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu.c

@@ -1336,23 +1336,29 @@ void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
 		kvm_mmu_write_protect_pt_masked(kvm, slot, gfn_offset, mask);
 }
 
-static bool rmap_write_protect(struct kvm_vcpu *vcpu, u64 gfn)
+bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
+				    struct kvm_memory_slot *slot, u64 gfn)
 {
-	struct kvm_memory_slot *slot;
 	struct kvm_rmap_head *rmap_head;
 	int i;
 	bool write_protected = false;
 
-	slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
-
 	for (i = PT_PAGE_TABLE_LEVEL; i <= PT_MAX_HUGEPAGE_LEVEL; ++i) {
 		rmap_head = __gfn_to_rmap(gfn, i, slot);
-		write_protected |= __rmap_write_protect(vcpu->kvm, rmap_head, true);
+		write_protected |= __rmap_write_protect(kvm, rmap_head, true);
 	}
 
 	return write_protected;
 }
 
+static bool rmap_write_protect(struct kvm_vcpu *vcpu, u64 gfn)
+{
+	struct kvm_memory_slot *slot;
+
+	slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
+	return kvm_mmu_slot_gfn_write_protect(vcpu->kvm, slot, gfn);
+}
+
 static bool kvm_zap_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head)
 {
 	u64 *sptep;

arch/x86/kvm/mmu.h

@@ -177,4 +177,6 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end);
 
 void kvm_mmu_gfn_disallow_lpage(struct kvm_memory_slot *slot, gfn_t gfn);
 void kvm_mmu_gfn_allow_lpage(struct kvm_memory_slot *slot, gfn_t gfn);
+bool kvm_mmu_slot_gfn_write_protect(struct kvm *kvm,
+				    struct kvm_memory_slot *slot, u64 gfn);
 #endif