memory-device: add device class function set_addr()

To be able to factor out address assignment of memory devices, we will
have to read (get_addr()) and write (set_addr()) the address.

We can't use properties for this purpose, as properties are device
specific. E.g. while the address property for a DIMM is called "addr", it
might be called differently (e.g. "memaddr") for other devices.

Especially virtio based memory devices cannot use "addr" as that is already
reserved and used for the address on the bus (for the proxy device).

Also, it might be possible to have memory devices without address
properties (e.g. internal DIMM-like thingies).

In contrast to get_addr(), we expect that set_addr() can fail.

Keep it simple for now for pc-dimm and simply set the static property, that
will fail once realized.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20181005092024.14344-13-david@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

hw/mem/pc-dimm.c

@@ -236,6 +236,12 @@ static uint64_t pc_dimm_md_get_addr(const MemoryDeviceState *md)
     return dimm->addr;
 }
 
+static void pc_dimm_md_set_addr(MemoryDeviceState *md, uint64_t addr,
+                                Error **errp)
+{
+    object_property_set_uint(OBJECT(md), addr, PC_DIMM_ADDR_PROP, errp);
+}
+
 static MemoryRegion *pc_dimm_md_get_memory_region(MemoryDeviceState *md,
                                                   Error **errp)
 {
@@ -286,6 +292,7 @@ static void pc_dimm_class_init(ObjectClass *oc, void *data)
     ddc->get_vmstate_memory_region = pc_dimm_get_memory_region;
 
     mdc->get_addr = pc_dimm_md_get_addr;
+    mdc->set_addr = pc_dimm_md_set_addr;
     /* for a dimm plugged_size == region_size */
     mdc->get_plugged_size = memory_device_get_region_size;
     mdc->get_memory_region = pc_dimm_md_get_memory_region;

include/hw/mem/memory-device.h

@@ -59,6 +59,14 @@ typedef struct MemoryDeviceClass {
      */
     uint64_t (*get_addr)(const MemoryDeviceState *md);
 
+    /*
+     * Set the address of the memory device in guest physical memory.
+     *
+     * Called when plugging the memory device to configure the determined
+     * address in guest physical memory.
+     */
+    void (*set_addr)(MemoryDeviceState *md, uint64_t addr, Error **errp);
+
     /*
      * Return the amount of memory provided by the memory device currently
      * usable ("plugged") by the VM.