On Fri, Jan 22, 2021 at 4:34 AM Bin Meng <[email protected]> wrote:
>
> From: Bin Meng <[email protected]>
>
> RV32 supports 34-bit physical address hence the maximum RAM size
> should be limitted. Limit the RAM size to 10 GiB, which leaves
> some room for PCIe high mmio space.
>
> Signed-off-by: Bin Meng <[email protected]>

Reviewed-by: Alistair Francis <[email protected]>

Alistair

> ---
>
>  hw/riscv/virt.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
>
> diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c
> index 1d05bb3ef9..4f44509360 100644
> --- a/hw/riscv/virt.c
> +++ b/hw/riscv/virt.c
> @@ -590,6 +590,19 @@ static void virt_machine_init(MachineState *machine)
>          }
>      }
>
> +    /* limit RAM size in a 32-bit system */
> +    if (riscv_is_32bit(&s->soc[0])) {
> +        /*
> +         * Cast machine->ram_size to 64-bit for 32-bit host,
> +         * to make the build on 32-bit host happy.
> +         */
> +        if ((uint64_t)(machine->ram_size) > 10 * GiB) {
> +            /* 32-bit host won't have a chance to execute here */
> +            machine->ram_size = 10 * GiB;
> +            error_report("Limitting RAM size to 10 GiB");
> +        }
> +    }
> +
>      /* register system main memory (actual RAM) */
>      memory_region_init_ram(main_mem, NULL, "riscv_virt_board.ram",
>                             machine->ram_size, &error_fatal);
> --
> 2.25.1
>
>

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