Re: [PATCH] hw/riscv: virt: bugfix the memory-backend-file command is invalid

[Bin Meng]

On Wed, Sep 29, 2021 at 10:03 PM MingWang Li <limingwang@huawei.com> wrote:
>
> From: Mingwang Li <limingwang@huawei.com>
>
> If default main_mem is used to be registered as the system memory,
> other memory cannot be initialized. Therefore, the system memory
> should be initialized to the machine->ram, which consists of the
> default main_mem and other possible memory required by applications,
> such as shared hugepage memory in DPDK.

Which command did you use to expose the error? It looks like not every
machine is done like this patch does.

Please reword the commit summary a little bit to help the understanding.

> Also, the mc->defaul_ram_id should be set to the default main_mem,
> which is named as "riscv_virt_board.ram".
>
> Signed-off-by: Mingwang Li <limingwang@huawei.com>
> Signed-off-by: Yifei Jiang <jiangyifei@huawei.com>
> ---
>  hw/riscv/virt.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c
> index ec0cb69b8c..b3b431c847 100644
> --- a/hw/riscv/virt.c
> +++ b/hw/riscv/virt.c
> @@ -771,7 +771,6 @@ static void virt_machine_init(MachineState *machine)
>      const MemMapEntry *memmap = virt_memmap;
>      RISCVVirtState *s = RISCV_VIRT_MACHINE(machine);
>      MemoryRegion *system_memory = get_system_memory();
> -    MemoryRegion *main_mem = g_new(MemoryRegion, 1);
>      MemoryRegion *mask_rom = g_new(MemoryRegion, 1);
>      char *plic_hart_config, *soc_name;
>      target_ulong start_addr = memmap[VIRT_DRAM].base;
> @@ -890,10 +889,8 @@ static void virt_machine_init(MachineState *machine)
>      }
>
>      /* register system main memory (actual RAM) */
> -    memory_region_init_ram(main_mem, NULL, "riscv_virt_board.ram",
> -                           machine->ram_size, &error_fatal);
>      memory_region_add_subregion(system_memory, memmap[VIRT_DRAM].base,
> -        main_mem);
> +        machine->ram);
>
>      /* create device tree */
>      create_fdt(s, memmap, machine->ram_size, machine->kernel_cmdline,
> @@ -1032,6 +1029,7 @@ static void virt_machine_class_init(ObjectClass *oc, 
> void *data)
>      mc->cpu_index_to_instance_props = riscv_numa_cpu_index_to_props;
>      mc->get_default_cpu_node_id = riscv_numa_get_default_cpu_node_id;
>      mc->numa_mem_supported = true;
> +    mc->default_ram_id = "riscv_virt_board.ram";
>
>      machine_class_allow_dynamic_sysbus_dev(mc, TYPE_RAMFB_DEVICE);
>
> --

Regards,
Bin