KVM: using get_fault_pfn to get the fault pfn

Using get_fault_pfn to cleanup the code
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

arch/x86/kvm/mmu.c

@@ -2513,10 +2513,8 @@ static pfn_t pte_prefetch_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn,
 	unsigned long hva;
 
 	slot = gfn_to_memslot_dirty_bitmap(vcpu, gfn, no_dirty_log);
-	if (!slot) {
-		get_page(fault_page);
-		return page_to_pfn(fault_page);
-	}
+	if (!slot)
+		return get_fault_pfn();
 
 	hva = gfn_to_hva_memslot(slot, gfn);
 

include/linux/kvm_host.h

@@ -383,15 +383,11 @@ id_to_memslot(struct kvm_memslots *slots, int id)
 static inline int is_error_hpa(hpa_t hpa) { return hpa >> HPA_MSB; }
 
 extern struct page *bad_page;
-extern struct page *fault_page;
-
 extern pfn_t bad_pfn;
-extern pfn_t fault_pfn;
 
 int is_error_page(struct page *page);
 int is_error_pfn(pfn_t pfn);
 int is_hwpoison_pfn(pfn_t pfn);
-int is_fault_pfn(pfn_t pfn);
 int is_noslot_pfn(pfn_t pfn);
 int is_invalid_pfn(pfn_t pfn);
 int kvm_is_error_hva(unsigned long addr);
@@ -441,6 +437,7 @@ void kvm_release_pfn_clean(pfn_t pfn);
 void kvm_set_pfn_dirty(pfn_t pfn);
 void kvm_set_pfn_accessed(pfn_t pfn);
 void kvm_get_pfn(pfn_t pfn);
+pfn_t get_fault_pfn(void);
 
 int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
 			int len);

virt/kvm/kvm_main.c

@@ -103,8 +103,8 @@ static bool largepages_enabled = true;
 static struct page *hwpoison_page;
 static pfn_t hwpoison_pfn;
 
-struct page *fault_page;
-pfn_t fault_pfn;
+static struct page *fault_page;
+static pfn_t fault_pfn;
 
 inline int kvm_is_mmio_pfn(pfn_t pfn)
 {
@@ -949,12 +949,6 @@ int is_hwpoison_pfn(pfn_t pfn)
 }
 EXPORT_SYMBOL_GPL(is_hwpoison_pfn);
 
-int is_fault_pfn(pfn_t pfn)
-{
-	return pfn == fault_pfn;
-}
-EXPORT_SYMBOL_GPL(is_fault_pfn);
-
 int is_noslot_pfn(pfn_t pfn)
 {
 	return pfn == bad_pfn;
@@ -1038,11 +1032,12 @@ unsigned long gfn_to_hva(struct kvm *kvm, gfn_t gfn)
 }
 EXPORT_SYMBOL_GPL(gfn_to_hva);
 
-static pfn_t get_fault_pfn(void)
+pfn_t get_fault_pfn(void)
 {
 	get_page(fault_page);
 	return fault_pfn;
 }
+EXPORT_SYMBOL_GPL(get_fault_pfn);
 
 int get_user_page_nowait(struct task_struct *tsk, struct mm_struct *mm,
 	unsigned long start, int write, struct page **page)