[PATCH v3 5/6] arm64/xen: introduce CONFIG_XEN and hypercall.S on ARM64

[Will Deacon]

On Wed, Jun 05, 2013 at 01:44:55PM +0100, Arnd Bergmann wrote:
> On Wednesday 05 June 2013 13:15:29 Stefano Stabellini wrote:
> > diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
> > index c95c5cb..79dd13d 100644
> > --- a/arch/arm64/Makefile
> > +++ b/arch/arm64/Makefile
> > @@ -37,6 +37,7 @@ TEXT_OFFSET := 0x00080000
> >  export TEXT_OFFSET GZFLAGS
> >  
> >  core-y         += arch/arm64/kernel/ arch/arm64/mm/
> > +core-$(CONFIG_XEN)             += arch/arm64/xen/
> >  libs-y         := arch/arm64/lib/ $(libs-y)
> >  libs-y         += $(LIBGCC)
> >  
> > diff --git a/arch/arm64/xen/Makefile b/arch/arm64/xen/Makefile
> > new file mode 100644
> > index 0000000..be24040
> > --- /dev/null
> > +++ b/arch/arm64/xen/Makefile
> > @@ -0,0 +1,2 @@
> > +xen-arm-y      += $(addprefix ../../arm/xen/, enlighten.o grant-table.o)
> > +obj-y          := xen-arm.o hypercall.o
> 
> I think it would be nicer to redirect the entire directory, not just
> the enlighten.o and grant-table.o files. You could do in arch/arm64/Makefile:
> 
> core-(CONFIG_XEN) += arch/arm/xen/
> 
> That leaves a small difference in hypercall.o, which I think you can
> handle with an #ifdef.
> 
> I believe the reason why KVM does the more elaborate variant is that
> they want to be able to build their code as a loadable module that
> also includes code from virt/kvm, which you don't need.

I thought we scrapped the idea of KVM as a loadable module on ARM, mainly
due to the complexities with retrospective initialisation of HYP mode/EL2?

Will