diff --git a/hw/xen_backend.c b/hw/xen_backend.c
index 24381b55e5..02693d7565 100644
--- a/hw/xen_backend.c
+++ b/hw/xen_backend.c
@@ -85,12 +85,20 @@ char *xenstore_read_str(const char *base, const char *node)
 
 int xenstore_write_int(const char *base, const char *node, int ival)
 {
-    char val[32];
+    char val[12];
 
     snprintf(val, sizeof(val), "%d", ival);
     return xenstore_write_str(base, node, val);
 }
 
+int xenstore_write_int64(const char *base, const char *node, int64_t ival)
+{
+    char val[21];
+
+    snprintf(val, sizeof(val), "%"PRId64, ival);
+    return xenstore_write_str(base, node, val);
+}
+
 int xenstore_read_int(const char *base, const char *node, int *ival)
 {
     char *val;
@@ -114,6 +122,11 @@ int xenstore_write_be_int(struct XenDevice *xendev, const char *node, int ival)
     return xenstore_write_int(xendev->be, node, ival);
 }
 
+int xenstore_write_be_int64(struct XenDevice *xendev, const char *node, int64_t ival)
+{
+    return xenstore_write_int64(xendev->be, node, ival);
+}
+
 char *xenstore_read_be_str(struct XenDevice *xendev, const char *node)
 {
     return xenstore_read_str(xendev->be, node);
diff --git a/hw/xen_backend.h b/hw/xen_backend.h
index 6d5c699c51..d04b985d10 100644
--- a/hw/xen_backend.h
+++ b/hw/xen_backend.h
@@ -63,11 +63,13 @@ extern const char *xen_protocol;
 /* xenstore helper functions */
 int xenstore_write_str(const char *base, const char *node, const char *val);
 int xenstore_write_int(const char *base, const char *node, int ival);
+int xenstore_write_int64(const char *base, const char *node, int64_t ival);
 char *xenstore_read_str(const char *base, const char *node);
 int xenstore_read_int(const char *base, const char *node, int *ival);
 
 int xenstore_write_be_str(struct XenDevice *xendev, const char *node, const char *val);
 int xenstore_write_be_int(struct XenDevice *xendev, const char *node, int ival);
+int xenstore_write_be_int64(struct XenDevice *xendev, const char *node, int64_t ival);
 char *xenstore_read_be_str(struct XenDevice *xendev, const char *node);
 int xenstore_read_be_int(struct XenDevice *xendev, const char *node, int *ival);
 char *xenstore_read_fe_str(struct XenDevice *xendev, const char *node);