virtio-rng: change default backend to rng-builtin

Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20190820160615.14616-4-lvivier@redhat.com>

backends/rng-builtin.c

@@ -10,7 +10,6 @@
 #include "qemu/main-loop.h"
 #include "qemu/guest-random.h"
 
-#define TYPE_RNG_BUILTIN "rng-builtin"
 #define RNG_BUILTIN(obj) OBJECT_CHECK(RngBuiltin, (obj), TYPE_RNG_BUILTIN)
 
 typedef struct RngBuiltin {

hw/virtio/virtio-rng.c

@@ -19,7 +19,6 @@
 #include "hw/virtio/virtio-rng.h"
 #include "sysemu/rng.h"
 #include "sysemu/runstate.h"
-#include "sysemu/rng-random.h"
 #include "qom/object_interfaces.h"
 #include "trace.h"
 
@@ -193,7 +192,7 @@ static void virtio_rng_device_realize(DeviceState *dev, Error **errp)
     }
 
     if (vrng->conf.rng == NULL) {
-        Object *default_backend = object_new(TYPE_RNG_RANDOM);
+        Object *default_backend = object_new(TYPE_RNG_BUILTIN);
 
         user_creatable_complete(USER_CREATABLE(default_backend),
                                 &local_err);

include/sysemu/rng.h

@@ -24,6 +24,8 @@
 #define RNG_BACKEND_CLASS(klass) \
     OBJECT_CLASS_CHECK(RngBackendClass, (klass), TYPE_RNG_BACKEND)
 
+#define TYPE_RNG_BUILTIN "rng-builtin"
+
 typedef struct RngRequest RngRequest;
 typedef struct RngBackendClass RngBackendClass;
 typedef struct RngBackend RngBackend;

qemu-options.hx

@@ -4337,7 +4337,7 @@ The @option{share} boolean option is @var{on} by default with memfd.
 Creates a random number generator backend which obtains entropy from
 QEMU builtin functions. The @option{id} parameter is a unique ID that
 will be used to reference this entropy backend from the @option{virtio-rng}
-device.
+device. By default, the @option{virtio-rng} device uses this RNG backend.
 
 @item -object rng-random,id=@var{id},filename=@var{/dev/random}