On Fri, 27 Jul 2012, Ian Campbell wrote:

On Thu, 2012-07-26 at 16:33 +0100, Stefano Stabellini wrote:

quoted

We used to rely on a core_initcall to initialize Xen on ARM, however
core_initcalls are actually called after early consoles are initialized.
That means that hvc_xen.c is going to be initialized before Xen.

Given the lack of a better alternative, just call a new Xen
initialization function (xen_guest_init) from xen_cons_init.

Can't we just arrange for this to be called super early on from
setup_arch? That's got to be better than calling it from some random
function which happens to get called early enough.

While I agree with you that an explicit call to xen_guest_init from
generic code might be better, xen_cons_init is not just a random
function: it is a console_initcall and therefore we know for sure that
it is going be the first one to be called.

In fact if we didn't want the PV console to work so early we could just
rely on a core_initcall to initialize everything and we wouldn't have
any issues.


In any case if the ARM maintainers agree I could add a generic
hypervisor initialization call the end of setup_arch.

I presume that KVM is going to want some similarly early init hooks etc
and therefore ARM could benefit from the same sort of infrastructure as
is in arch/x86/include/asm/hypervisor.h?