[RFC,v2,3/6] KVM: introduce a wrapper function to copy dirty bitmaps to user space

Commit Message

Takuya Yoshikawa April 20, 2010, 10:59 a.m. UTC

None

Patch

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 76b23ed..6f0b706 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2771,9 +2771,7 @@  int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
 		kfree(old_slots);
 	}
 
-	r = 0;
-	if (copy_to_user(log->dirty_bitmap, dirty_bitmap, n))
-		r = -EFAULT;
+	r = kvm_copy_dirty_bitmap(log->dirty_bitmap, dirty_bitmap, n);
 out_free:
 	vfree(dirty_bitmap);
 out:
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 4446622..42b7161 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -330,6 +330,9 @@  long kvm_arch_vcpu_ioctl(struct file *filp,
 
 int kvm_dev_ioctl_check_extension(long ext);
 
+int kvm_copy_dirty_bitmap(unsigned long __user *to,
+			  const unsigned long *from,
+			  unsigned long bytes);
 int kvm_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log);
 int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
 				struct kvm_dirty_log *log);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 40a6888..6908304 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -777,6 +777,16 @@  int kvm_vm_ioctl_set_memory_region(struct kvm *kvm,
 	return kvm_set_memory_region(kvm, mem, user_alloc);
 }
 
+int kvm_copy_dirty_bitmap(unsigned long __user *to,
+			  const unsigned long *from,
+			  unsigned long bytes)
+{
+	if (copy_to_user(to, from, bytes))
+		return -EFAULT;
+
+	return 0;
+}
+
 int kvm_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
 {
 	struct kvm_memory_slot *memslot;
@@ -795,7 +805,7 @@  int kvm_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
 	n = kvm_dirty_bitmap_bytes(memslot);
 
 	r = -EFAULT;
-	if (copy_to_user(log->dirty_bitmap, memslot->dirty_bitmap, n))
+	if (kvm_copy_dirty_bitmap(log->dirty_bitmap, memslot->dirty_bitmap, n))
 		goto out;
 
 	r = 0;