Re: UEFI support in ARM DomUs

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 24 Jun 2020, Oleksandr Andrushchenko wrote:
> On 6/24/20 8:05 PM, Stefano Stabellini wrote:
> > On Wed, 24 Jun 2020, Oleksandr Andrushchenko wrote:
> >> On 6/23/20 8:31 AM, Oleksandr Andrushchenko wrote:
> >>> 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
> >> We've managed to strip the headers and remove __XEN__ and the rest 
> >> definitions
> >>
> >> we were talking about. So, these are now the minimal required set of 
> >> headers
> >>
> >> that allows U-boot to build serial and block drivers. Please take a look 
> >> at [1]
> >>
> >> Pull request for comments is at [2]
> > I think this is the right approach. There is no build-dependency on Xen
> > anymore, is that correct?
>
> No dependency

Great!