Re: xen & FPU

["Christian Limpach" <Christian.Limpach%cl.cam.ac.uk@localhost>]

From: "Matthias Scheler" <tron%zhadum.de@localhost>
> In article <20050318165855.GB6095%antioche.lip6.fr@localhost>,
> Manuel Bouyer <bouyer%antioche.lip6.fr@localhost> writes:
> > Well, is seems that the FPU stuff needs more work. From xen/i386/npx.c:
> > int
> > npxintr(void *arg, struct intrframe iframe)
> > {
> >         struct cpu_info *ci = curcpu();
> >         struct lwp *l = ci->ci_fpcurlwp;
> >         union savefpu *addr;
> >         struct intrframe *frame = &iframe;
> >         struct npx_softc *sc;
> >         ksiginfo_t ksi;
> >
> >         sc = npx_softc;
> >
> >         uvmexp.traps++;
> >         IPRINTF(("%s: fp intr\n", ci->ci_dev->dv_xname));
> >         panic("not supported\n");
>
> This code handles FPU exceptions, correct? Will each domain see its on
> exception or has domain0 to handle them all?

It handles FPU errors, the context switching part of FPU exception handling 
is in npxdna_*.  Both types of exceptions get always passed up to the domain 
causing the exception.  I would try removing the panic and also commenting 
out the bus_space_write which is just following it.  The rest of the code 
looks like it could just work...

    christian