memory: add error propagation to file-based RAM allocation

Right now, -mem-path will fall back to RAM-based allocation in some
cases.  This should never happen with "-object memory-file", prepare
the code by adding correct error propagation.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

MST: drop \n at end of error messages

include/exec/memory.h

@@ -31,6 +31,7 @@
 #include "qemu/queue.h"
 #include "qemu/int128.h"
 #include "qemu/notify.h"
+#include "qapi/error.h"
 
 #define MAX_PHYS_ADDR_SPACE_BITS 62
 #define MAX_PHYS_ADDR            (((hwaddr)1 << MAX_PHYS_ADDR_SPACE_BITS) - 1)
@@ -321,12 +322,14 @@ void memory_region_init_ram(MemoryRegion *mr,
  * @name: the name of the region.
  * @size: size of the region.
  * @path: the path in which to allocate the RAM.
+ * @errp: pointer to Error*, to store an error if it happens.
  */
 void memory_region_init_ram_from_file(MemoryRegion *mr,
                                       struct Object *owner,
                                       const char *name,
                                       uint64_t size,
-                                      const char *path);
+                                      const char *path,
+                                      Error **errp);
 #endif
 
 /**

include/exec/ram_addr.h

@@ -23,7 +23,7 @@
 #include "hw/xen/xen.h"
 
 ram_addr_t qemu_ram_alloc_from_file(ram_addr_t size, MemoryRegion *mr,
-                                    const char *mem_path);
+                                    const char *mem_path, Error **errp);
 ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host,
                                    MemoryRegion *mr);
 ram_addr_t qemu_ram_alloc(ram_addr_t size, MemoryRegion *mr);