diff --git a/src/libxl/libxl_api_wrapper.h b/src/libxl/libxl_api_wrapper.h
index a9627f7983..c9582294cc 100644
--- a/src/libxl/libxl_api_wrapper.h
+++ b/src/libxl/libxl_api_wrapper.h
@@ -193,24 +193,20 @@ libxlSendTriggerWrapper(libxl_ctx *ctx,
 static inline int
 libxlSetMemoryTargetWrapper(libxl_ctx *ctx,
                         uint32_t domid,
-                        uint64_t target_memkb,
+                        int64_t target_memkb,
                         int relative,
                         int enforce)
 {
     int ret = -1;
 
-    /* Technically this guard could be LIBXL_HAVE_MEMKB_64BITS */
-#if LIBXL_API_VERSION < 0x040800
-    if (target_memkb < UINT_MAX) {
-        uint32_t val32 = target_memkb;
+#ifdef LIBXL_HAVE_MEMKB_64BITS
+    ret = libxl_set_memory_target(ctx, domid, target_memkb, relative, enforce);
+#else
+    if (target_memkb < INT_MAX) {
+        int32_t val32 = target_memkb;
 
         ret = libxl_set_memory_target(ctx, domid, val32, relative, enforce);
     }
-#else
-    if (target_memkb < LLONG_MAX) {
-        int64_t val64 = target_memkb;
-        ret = libxl_set_memory_target(ctx, domid, val64, relative, enforce);
-    }
 #endif
 
     return ret;
diff --git a/src/libxl/libxl_domain.c b/src/libxl/libxl_domain.c
index 6c167df63e..0c4beffd6a 100644
--- a/src/libxl/libxl_domain.c
+++ b/src/libxl/libxl_domain.c
@@ -926,7 +926,7 @@ libxlDomainFreeMem(libxl_ctx *ctx, libxl_domain_config *d_config)
 {
     uint64_t needed_mem;
     uint64_t free_mem;
-    uint64_t target_mem;
+    int64_t target_mem;
     int tries = 3;
     int wait_secs = 10;