[PATCH 02/10] memory-device: Introduce memory_devices_init()

[David Hildenbrand <david@redhat.com>]

Let's intrduce a new helper that we will use to replace existing memory
device setup code during machine initialization. We'll enforce that the
size has to be > 0.

Once all machines were converted, we'll only allocate ms->device_memory
if the size > 0.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 hw/mem/memory-device.c         | 14 ++++++++++++++
 include/hw/mem/memory-device.h |  2 ++
 2 files changed, 16 insertions(+)

diff --git a/hw/mem/memory-device.c b/hw/mem/memory-device.c
index 49f86ec8a8..2197dcf356 100644
--- a/hw/mem/memory-device.c
+++ b/hw/mem/memory-device.c
@@ -17,6 +17,7 @@
 #include "qemu/range.h"
 #include "hw/virtio/vhost.h"
 #include "sysemu/kvm.h"
+#include "exec/address-spaces.h"
 #include "trace.h"
 
 static gint memory_device_addr_sort(gconstpointer a, gconstpointer b)
@@ -328,6 +329,19 @@ uint64_t memory_device_get_region_size(const MemoryDeviceState *md,
     return memory_region_size(mr);
 }
 
+void memory_devices_init(MachineState *ms, hwaddr base, uint64_t size)
+{
+    g_assert(size);
+    g_assert(!ms->device_memory);
+    ms->device_memory = g_new0(DeviceMemoryState, 1);
+    ms->device_memory->base = base;
+
+    memory_region_init(&ms->device_memory->mr, OBJECT(ms), "device-memory",
+                       size);
+    memory_region_add_subregion(get_system_memory(), ms->device_memory->base,
+                                &ms->device_memory->mr);
+}
+
 static const TypeInfo memory_device_info = {
     .name          = TYPE_MEMORY_DEVICE,
     .parent        = TYPE_INTERFACE,
diff --git a/include/hw/mem/memory-device.h b/include/hw/mem/memory-device.h
index 48d2611fc5..6e8a10e2f5 100644
--- a/include/hw/mem/memory-device.h
+++ b/include/hw/mem/memory-device.h
@@ -16,6 +16,7 @@
 #include "hw/qdev-core.h"
 #include "qapi/qapi-types-machine.h"
 #include "qom/object.h"
+#include "exec/hwaddr.h"
 
 #define TYPE_MEMORY_DEVICE "memory-device"
 
@@ -113,5 +114,6 @@ void memory_device_plug(MemoryDeviceState *md, MachineState *ms);
 void memory_device_unplug(MemoryDeviceState *md, MachineState *ms);
 uint64_t memory_device_get_region_size(const MemoryDeviceState *md,
                                        Error **errp);
+void memory_devices_init(MachineState *ms, hwaddr base, uint64_t size);
 
 #endif
-- 
2.40.1