Re: [PATCH 2/6] hw/riscv: opentitan: Use MachineState::ram and MachineClass::default_ram_id

[Igor Mammedov <imammedo@redhat.com>]

On Mon, 18 Oct 2021 23:38:25 +0800
Bin Meng <bmeng.cn@gmail.com> wrote:

> Using memory_region_init_ram(), which can't possibly handle vhost-user,
> and can't work as expected with '-numa node,memdev' options.
> 
> Use MachineState::ram instead of manually initializing RAM memory
> region, as well as by providing MachineClass::default_ram_id to
> opt in to memdev scheme.
> 
> Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
> ---
> 
>  hw/riscv/opentitan.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/riscv/opentitan.c b/hw/riscv/opentitan.c
> index 9803ae6d70..c356293d29 100644
> --- a/hw/riscv/opentitan.c
> +++ b/hw/riscv/opentitan.c
> @@ -67,17 +67,14 @@ static void opentitan_board_init(MachineState *machine)
>      const MemMapEntry *memmap = ibex_memmap;
>      OpenTitanState *s = g_new0(OpenTitanState, 1);
>      MemoryRegion *sys_mem = get_system_memory();
> -    MemoryRegion *main_mem = g_new(MemoryRegion, 1);

It is likely that you are missing fixed size check here
(looking at code it seems to me that board doesn't support variable RAM size)
See commit 00b9829f83c for example.

>      /* Initialize SoC */
>      object_initialize_child(OBJECT(machine), "soc", &s->soc,
>                              TYPE_RISCV_IBEX_SOC);
>      qdev_realize(DEVICE(&s->soc), NULL, &error_abort);
>  
> -    memory_region_init_ram(main_mem, NULL, "riscv.lowrisc.ibex.ram",
> -        memmap[IBEX_DEV_RAM].size, &error_fatal);
>      memory_region_add_subregion(sys_mem,
> -        memmap[IBEX_DEV_RAM].base, main_mem);
> +        memmap[IBEX_DEV_RAM].base, machine->ram);
>  
>      if (machine->firmware) {
>          riscv_load_firmware(machine->firmware, memmap[IBEX_DEV_RAM].base, NULL);
> @@ -95,6 +92,7 @@ static void opentitan_machine_init(MachineClass *mc)
>      mc->init = opentitan_board_init;
>      mc->max_cpus = 1;
>      mc->default_cpu_type = TYPE_RISCV_CPU_IBEX;
> +    mc->default_ram_id = "riscv.lowrisc.ibex.ram";

Are you missing "mc->default_ram_size = memmap[IBEX_DEV_RAM].size" here?

otherwise it will default to generic:
  hw/core/machine.c:    mc->default_ram_size = 128 * MiB;

>  }
>  
>  DEFINE_MACHINE("opentitan", opentitan_machine_init)