Re: UEFI support in ARM DomUs

[Oleksandr Andrushchenko <Oleksandr_Andrushchenko@xxxxxxxx>]

On 6/23/20 4:20 AM, Stefano Stabellini wrote:
> On Mon, 22 Jun 2020, Julien Grall wrote:
>>>>> For the first part (__XEN_INTERFACE_VERSION__) I think we can provide it
>>>>> via
>>>>>
>>>>> CFLAGS or something. This can also be done for the location of Xen
>>>>> headers.
>>>> __XEN_INTERFACE_VERSION__ should work through the CFLAGS. An alternative
>>>> would be to allow the user to specify through the Kconfig.
>>> You mean specifying via Kconfig something like "0x00040d00"?
>> Possibly yes.
>>
>>> And what about the headers? How will we provide their location if we decide
>>> not to include those
>>>
>>> in the tree?
>> I would do through Kconfig as well.
> If we specify the external location of the Xen headers via Kconfig, it
> seems to me that we should be able to detect the interface version
> automatically from any Makefile as part of the build. No need to ask the
> user.
>
> However, if Oleksandr is thinking of using the Xen headers for the
> hypercalls definitions, then I think we might not need external headers
> at all because that is a stable interface, as Julien wrote. We could
> just define our own few headers for just what you need like Linux does.

This is a good idea: I'll try to get the minimal set of headers from Linux

instead of Xen as those seem to be well prepared for such a use-case. This

way we'll have headers in U-boot tree and guarantee that we have a minimal

subset which is easier to maintain. I'll keep you updated on the progress

>
> If you can do that, I think it would be better because we decouple the
> UBoot build from the Xen build completely. We don't even need the Xen
> tree checked out to build UBoot. It would be a huge advantage because it
> makes it far easier to build-test changes for others in the community
> that don't know about Xen and also it becomes far easier to integrate
> into any build system.