KVM: introduce KVM_PFN_ERR_FAULT

After that, the exported and un-inline function, get_fault_pfn,
can be removed

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/mmu.c

@@ -2512,7 +2512,7 @@ static pfn_t pte_prefetch_gfn_to_pfn(struct kvm_vcpu *vcpu, gfn_t gfn,
 
 	slot = gfn_to_memslot_dirty_bitmap(vcpu, gfn, no_dirty_log);
 	if (!slot)
-		return get_fault_pfn();
+		return KVM_PFN_ERR_FAULT;
 
 	hva = gfn_to_hva_memslot(slot, gfn);
 

include/linux/kvm_host.h

@@ -48,6 +48,8 @@
 #define KVM_MAX_MMIO_FRAGMENTS \
 	(KVM_MMIO_SIZE / KVM_USER_MMIO_SIZE + KVM_EXTRA_MMIO_FRAGMENTS)
 
+#define KVM_PFN_ERR_FAULT	(-EFAULT)
+
 /*
  * vcpu->requests bit members
  */
@@ -443,7 +445,6 @@ 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

@@ -939,12 +939,6 @@ static pfn_t get_bad_pfn(void)
 	return -ENOENT;
 }
 
-pfn_t get_fault_pfn(void)
-{
-	return -EFAULT;
-}
-EXPORT_SYMBOL_GPL(get_fault_pfn);
-
 static pfn_t get_hwpoison_pfn(void)
 {
 	return -EHWPOISON;
@@ -1115,7 +1109,7 @@ static pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
 		struct vm_area_struct *vma;
 
 		if (atomic)
-			return get_fault_pfn();
+			return KVM_PFN_ERR_FAULT;
 
 		down_read(&current->mm->mmap_sem);
 		if (npages == -EHWPOISON ||
@@ -1127,7 +1121,7 @@ static pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
 		vma = find_vma_intersection(current->mm, addr, addr+1);
 
 		if (vma == NULL)
-			pfn = get_fault_pfn();
+			pfn = KVM_PFN_ERR_FAULT;
 		else if ((vma->vm_flags & VM_PFNMAP)) {
 			pfn = ((addr - vma->vm_start) >> PAGE_SHIFT) +
 				vma->vm_pgoff;
@@ -1135,7 +1129,7 @@ static pfn_t hva_to_pfn(unsigned long addr, bool atomic, bool *async,
 		} else {
 			if (async && (vma->vm_flags & VM_WRITE))
 				*async = true;
-			pfn = get_fault_pfn();
+			pfn = KVM_PFN_ERR_FAULT;
 		}
 		up_read(&current->mm->mmap_sem);
 	} else