Re: [Qemu-devel] [PATCH 0/3] Add new utility function memory_region_allocate_aux_memory()

[Peter Maydell]

On 5 July 2017 at 13:21, Paolo Bonzini <address@hidden> wrote:
>
>
> On 04/07/2017 19:02, Peter Maydell wrote:
>> Many board models and several devices need to create auxiliary
>> regions of RAM (in addition to the main lump of 'system' memory),
>> to model static RAMs, video memory, ROMs, etc. Currently they do
>> this with a sequence like:
>>        memory_region_init_ram(sram, NULL, "sram", 0x10000, &error_fatal);
>>        vmstate_register_ram_global(sram);
>
> Instead of vmstate_register_ram_global, you should use
>
>     vmstate_register_ram(mr, owner);
>
> You should even do it for all memory regions, probably.

Slightly awkward because owner is an Object but vmstate_register_ram()
needs a DeviceState. Is this OK, or too much magic?

    DeviceState *owner_dev;
    Error *err = NULL;

    memory_region_init_ram(mr, owner, name, ram_size, &err);
    if (err) {
        error_propagate(errp, err);
        return;
    }
    /* Note that owner_dev may be NULL if owner is not a DeviceState;
     * in that case this is equivalent to calling vmstate_register_ram_global().
     */
    owner_dev = object_dynamic_cast(owner, TYPE_DEVICE);
    vmstate_register_ram(mr, owner_dev);

thanks
-- PMM