diff --git a/hw/boards.h b/hw/boards.h
index 7fb2df50f4..659c5590c5 100644
--- a/hw/boards.h
+++ b/hw/boards.h
@@ -15,7 +15,7 @@ typedef struct QEMUMachine {
     const char *desc;
     QEMUMachineInitFunc *init;
 #define RAMSIZE_FIXED	(1 << 0)
-    size_t ram_require;
+    ram_addr_t ram_require;
     struct QEMUMachine *next;
 } QEMUMachine;
 
diff --git a/vl.c b/vl.c
index 2b6e459b22..c30a87faa7 100644
--- a/vl.c
+++ b/vl.c
@@ -8277,7 +8277,7 @@ int main(int argc, char **argv)
     machine = first_machine;
     cpu_model = NULL;
     initrd_filename = NULL;
-    ram_size = -1;
+    ram_size = 0;
     vga_ram_size = VGA_RAM_SIZE;
 #ifdef CONFIG_GDBSTUB
     use_gdbstub = 0;
@@ -9000,7 +9000,7 @@ int main(int argc, char **argv)
         } else
             ram_size = phys_ram_size;
     } else {
-        if (ram_size < 0)
+        if (ram_size == 0)
             ram_size = DEFAULT_RAM_SIZE * 1024 * 1024;
 
         phys_ram_size += ram_size;