Re: [Xen-devel] [PATCH v7 2/3] * util/grub.d/20_linux_xen.in: Add xen_boot command support for aarch64

[Fu Wei]

Hi Stefano,

On 4 May 2017 at 04:53, Stefano Stabellini <address@hidden> wrote:
> On Wed, 3 May 2017, Andrew Cooper wrote:
>> On 02/05/17 08:06, address@hidden wrote:
>> > From: Fu Wei <address@hidden>
>> >
>> > This patch adds the support of xen_boot command for aarch64:
>> >     xen_hypervisor
>> >     xen_module
>> > These two commands are only for aarch64, since it has its own protocol and
>> > commands to boot xen hypervisor and Dom0, but not multiboot.
>> >
>> > For other architectures, they are still using multiboot and module
>> > commands.
>> >
>> > Signed-off-by: Fu Wei <address@hidden>
>>
>> Sorry if I am jumping in late and asking awkward questions, but what is
>> special about Xen/aarch64 here?  Why is it using a non-standard entry
>> mechanism?
>
> Multiboot is not available on ARM. The boot protocol we have on ARM is
> FDT based:
>
> http://xenbits.xen.org/gitweb/?p=xen.git;a=blob;f=docs/misc/arm/device-tree/booting.txt
>
> We often refer to it as "multiboot for arm" but in fact it is not
> related to the x86 multiboot in any way.
>
> In Grub, the two protocols (multiboot and
> docs/misc/arm/device-tree/booting.txt) are kept clearly distinct
> (address@hidden). Hence, the need for this patch.

Exactly, great thanks for your explanation! :-)



-- 
Best regards,

Fu Wei
Software Engineer
Red Hat