Re: [Qemu-devel] [PATCH 2/4] multiboot: load any machine type of ELF

[Anatol Pomozov]

Hi

On Fri, Oct 13, 2017 at 12:25 PM, Eduardo Habkost <address@hidden> wrote:
> On Thu, Oct 12, 2017 at 04:54:37PM -0700, Anatol Pomozov wrote:
>> x86 is not the only architecture supported by multiboot.
>> For example GRUB supports MIPS architecture as well.
>>
>> Signed-off-by: Anatol Pomozov <address@hidden>
>> ---
>>  hw/i386/multiboot.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/hw/i386/multiboot.c b/hw/i386/multiboot.c
>> index c9254f313e..7dacd6d827 100644
>> --- a/hw/i386/multiboot.c
>> +++ b/hw/i386/multiboot.c
>> @@ -173,7 +173,7 @@ int load_multiboot(FWCfgState *fw_cfg,
>>          }
>>
>>          kernel_size = load_elf(kernel_filename, NULL, NULL, &elf_entry,
>> -                               &elf_low, &elf_high, 0, I386_ELF_MACHINE,
>> +                               &elf_low, &elf_high, 0, EM_NONE,
>>                                 0, 0);
>
> I assume we still want PC to reject non-x86 ELF files.

Does multiboot spec states this restriction? I've heard that there are
attempts to implement multiboot at ARM [1] [2]. Also multiboot2 spec
mentions MIPS as one of the target architectures.

[1] https://github.com/jncronin/rpi-boot/blob/master/MULTIBOOT-ARM
[2] https://wiki.linaro.org/AndrePrzywara/Multiboot

>  Isn't it
> better to add a elf_machine argument to load_multiboot() so each
> load_multiboot() caller can specify what's the expected
> architecture?
>
>
>>          if (kernel_size < 0) {
>>              fprintf(stderr, "Error while loading elf kernel\n");
>> --
>> 2.15.0.rc0.271.g36b669edcc-goog
>>
>
> --
> Eduardo