Re: UEFI support in ARM DomUs

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

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?