machine: alias -mem-path and -mem-prealloc into memory-foo backend

Allow machine to opt in for hostmem backend based initial RAM
even if user uses old -mem-path/prealloc options by providing
  MachineClass::default_ram_id
Follow up patches will incrementally convert machines to new API,
by dropping memory_region_allocate_system_memory() and setting
default_ram_id that board used to use before conversion to keep
migration stream the same.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20200219160953.13771-4-imammedo@redhat.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/vl.c b/vl.c
index 794f2e5733..4dc4803611 100644
--- a/vl.c
+++ b/vl.c
@@ -75,6 +75,7 @@ int main(int argc, char **argv)
 #include "ui/input.h"
 #include "sysemu/sysemu.h"
 #include "sysemu/numa.h"
+#include "sysemu/hostmem.h"
 #include "exec/gdbstub.h"
 #include "qemu/timer.h"
 #include "chardev/char.h"
@@ -2805,6 +2806,26 @@ static void configure_accelerators(const char *progname)
     }
 }
 
+static void create_default_memdev(MachineState *ms, const char *path,
+                                  bool prealloc)
+{
+    Object *obj;
+    MachineClass *mc = MACHINE_GET_CLASS(ms);
+
+    obj = object_new(path ? TYPE_MEMORY_BACKEND_FILE : TYPE_MEMORY_BACKEND_RAM);
+    if (path) {
+        object_property_set_str(obj, path, "mem-path", &error_fatal);
+    }
+    object_property_set_bool(obj, prealloc, "prealloc", &error_fatal);
+    object_property_set_int(obj, ms->ram_size, "size", &error_fatal);
+    object_property_add_child(object_get_objects_root(), mc->default_ram_id,
+                              obj, &error_fatal);
+    user_creatable_complete(USER_CREATABLE(obj), &error_fatal);
+    object_unref(obj);
+    object_property_set_str(OBJECT(ms), mc->default_ram_id, "memory-backend",
+                            &error_fatal);
+}
+
 int main(int argc, char **argv, char **envp)
 {
     int i;
@@ -4268,6 +4289,10 @@ int main(int argc, char **argv, char **envp)
     }
     parse_numa_opts(current_machine);
 
+    if (machine_class->default_ram_id && current_machine->ram_size &&
+        !current_machine->ram_memdev_id) {
+        create_default_memdev(current_machine, mem_path, mem_prealloc);
+    }
     /* do monitor/qmp handling at preconfig state if requested */
     main_loop();