Re: [RFC PATCH v7 24/29] hw/loongarch: Add default bios startup support.

[Richard Henderson <richard.henderson@linaro.org>]

On 3/28/22 06:57, Xiaojuan Yang wrote:
> Signed-off-by: Xiaojuan Yang<yangxiaojuan@loongson.cn>
> Signed-off-by: Song Gao<gaosong@loongson.cn>
> ---
>   hw/loongarch/Kconfig             |  4 ++
>   hw/loongarch/fw_cfg.c            | 33 ++++++++++++++
>   hw/loongarch/fw_cfg.h            | 15 +++++++
>   hw/loongarch/loongson3.c         | 76 +++++++++++++++++++++++++++++++-
>   hw/loongarch/meson.build         |  1 +
>   include/hw/loongarch/loongarch.h |  8 ++++
>   6 files changed, 135 insertions(+), 2 deletions(-)
>   create mode 100644 hw/loongarch/fw_cfg.c
>   create mode 100644 hw/loongarch/fw_cfg.h

Not within this patch, but you will want to create a submodule for this bios image, as we 
do for roms/edk2 etc.  You will want to commit a pre-built image as well, like we do for 
other targets.

> +    /* load the BIOS image. */
> +    filename = qemu_find_file(QEMU_FILE_TYPE_BIOS,
> +                              machine->firmware ?: LOONGSON3_BIOSNAME);
> +    if (filename) {
> +        bios_size = load_image_targphys(filename, LA_BIOS_BASE, LA_BIOS_SIZE);
> +        lams->fw_cfg = loongarch_fw_cfg_init(ram_size, machine);
> +        rom_set_fw(lams->fw_cfg);
> +        g_free(filename);
> +    } else {
> +        bios_size = -1;
> +    }

While loading the efi bios may be the most common usage, it's not efficient for simple 
tests.  I think you should attempt to load an elf image, and only if that fails treat it 
as the firmware blob that efi builds.

Or not require a bios image if -kernel is present, or something.
At the moment one cannot run the tests/tcg/multiarch tests without loongarch.bios.


r~