Re: [PATCH ARM v8 2/4] mini-os: arm: interrupt controller

[Ian Campbell <Ian.Campbell@citrix.com>]

On Tue, 2014-10-21 at 19:14 +0100, Anil Madhavapeddy wrote:
> On 21 Oct 2014, at 17:03, Julien Grall <julien.grall@linaro.org> wrote:
> > 
> >>> In this case, it would make mini-os working directly on Xen 4.4.
> > 
> >> and how long should mini-os carry this hack for then?
> > 
> > The current issue could be considered as an hardware bug (even though
> > it's an emulation). Time to time guest has to deal with hardware bug. As
> > long as it's very simple to fix it and doesn't impact performance, I
> > guess it's better to have it forever.
> > In this case, interrupts will be configured only once during mini-os
> > initialization.
> > 
> > If nobody care about running mini-os on current version of current Xen
> > 4.4.x, then fine.

Anybody who cares should fix the bug in Xen.  It would have taken less
typing than this thread.

> Isn't this what XEN_INTERFACE_VERSION checks are for?  It's certainly
> convenient to have MiniOS support the last stable version of the Xen
> ABI unless it's a huge diff, and this should just be a localised #ifdef.

This isn't an ABI issue, it's a violation of a hardware spec which we
are supposed to be emulating.

In any case XEN_INTERFACE_VERSION is for API compatiblity (for users of
the Xen headers), not ABI compatibility.

Ian.