memory_region_allocate_system_memory() API is going away,
so replace it with memdev allocated MemoryRegion.
The later is initialized by generic code, so board only
needs to opt in to memdev scheme by providing
  MachineClass::default_ram_id
and then map memory region provided by
  MachineState::ram_memdev

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 hw/arm/virt.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index f788fe27d6..e591a126e7 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -1512,7 +1512,6 @@ static void machvirt_init(MachineState *machine)
     MemoryRegion *sysmem = get_system_memory();
     MemoryRegion *secure_sysmem = NULL;
     int n, virt_max_cpus;
-    MemoryRegion *ram = g_new(MemoryRegion, 1);
     bool firmware_loaded;
     bool aarch64 = true;
     bool has_ged = !vmc->no_ged;
@@ -1706,9 +1705,8 @@ static void machvirt_init(MachineState *machine)
         }
     }
 
-    memory_region_allocate_system_memory(ram, NULL, "mach-virt.ram",
-                                         machine->ram_size);
-    memory_region_add_subregion(sysmem, vms->memmap[VIRT_MEM].base, ram);
+    memory_region_add_subregion(sysmem, vms->memmap[VIRT_MEM].base,
+                                machine->ram);
     if (machine->device_memory) {
         memory_region_add_subregion(sysmem, machine->device_memory->base,
                                     &machine->device_memory->mr);
@@ -2058,6 +2056,7 @@ static void virt_machine_class_init(ObjectClass *oc, void *data)
     hc->unplug_request = virt_machine_device_unplug_request_cb;
     mc->numa_mem_supported = true;
     mc->auto_enable_numa_with_memhp = true;
+    mc->default_ram_id = "mach-virt.ram";
 }
 
 static void virt_instance_init(Object *obj)
-- 
2.18.1