From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:59422)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <anatol.pomozov@gmail.com>) id 1e37Sj-0007PC-Nr
	for qemu-devel@nongnu.org; Fri, 13 Oct 2017 17:25:46 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <anatol.pomozov@gmail.com>) id 1e37Si-0000J2-KS
	for qemu-devel@nongnu.org; Fri, 13 Oct 2017 17:25:45 -0400
Received: from mail-ua0-x241.google.com ([2607:f8b0:400c:c08::241]:54403)
	by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16)
	(Exim 4.71) (envelope-from <anatol.pomozov@gmail.com>)
	id 1e37Si-0000Ij-FR
	for qemu-devel@nongnu.org; Fri, 13 Oct 2017 17:25:44 -0400
Received: by mail-ua0-x241.google.com with SMTP id n38so6182328uai.11
	for <qemu-devel@nongnu.org>; Fri, 13 Oct 2017 14:25:44 -0700 (PDT)
MIME-Version: 1.0
In-Reply-To: <20171013192550.GC3246@localhost.localdomain>
References: <20171012235439.19457-1-anatol.pomozov@gmail.com>
	<20171012235439.19457-3-anatol.pomozov@gmail.com>
	<20171013192550.GC3246@localhost.localdomain>
From: Anatol Pomozov <anatol.pomozov@gmail.com>
Date: Fri, 13 Oct 2017 14:25:43 -0700
Message-ID: <CAOMFOmW+r86WHWPUMtG54BrAQXqSWZ67oF-6G697ox-7AKL4GA@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
Subject: Re: [Qemu-devel] [PATCH 2/4] multiboot: load any machine type of ELF
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel/>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Eduardo Habkost <ehabkost@redhat.com>
Cc: qemu-devel@nongnu.org, Kevin Wolf <kwolf@redhat.com>, Richard Henderson <rth@twiddle.net>, Paolo Bonzini <pbonzini@redhat.com>, Alexander Graf <agraf@suse.de>, "Michael S. Tsirkin" <mst@redhat.com>

Hi

On Fri, Oct 13, 2017 at 12:25 PM, Eduardo Habkost <ehabkost@redhat.com> 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 <anatol.pomozov@gmail.com>
>> ---
>>  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