diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index cc983bedbd..1bbfeb25b1 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -540,17 +540,19 @@ static abi_long target_mmap__locked(abi_ulong start, abi_ulong len,
     host_offset = offset & -host_page_size;
 
     /*
-     * If the user is asking for the kernel to find a location, do that
-     * before we truncate the length for mapping files below.
+     * For reserved_va, we are in full control of the allocation.
+     * Find a suitable hole and convert to MAP_FIXED.
      */
-    if (!(flags & (MAP_FIXED | MAP_FIXED_NOREPLACE))) {
+    if (reserved_va && !(flags & (MAP_FIXED | MAP_FIXED_NOREPLACE))) {
         host_len = len + offset - host_offset;
-        host_len = ROUND_UP(host_len, host_page_size);
-        start = mmap_find_vma(real_start, host_len, TARGET_PAGE_SIZE);
+        start = mmap_find_vma(real_start, host_len,
+                              MAX(host_page_size, TARGET_PAGE_SIZE));
         if (start == (abi_ulong)-1) {
             errno = ENOMEM;
             return -1;
         }
+        start += offset - host_offset;
+        flags |= MAP_FIXED;
     }
 
     /*