On Mon, Mar 30, 2015 at 11:41 AM, Ian Campbell <ian.campb...@citrix.com>
wrote:
> On Fri, 2015-03-27 at 22:18 +0000, Tamas K Lengyel wrote:
>
> >
> > > union hsr hsr)
> > > {
> > > - register_t addr = READ_SYSREG(FAR_EL2);
> > > - inject_iabt_exception(regs, addr, hsr.len);
> > > + struct hsr_iabt iabt = hsr.iabt;
> > > + int rc;
> > > + paddr_t gpa;
> > > + register_t gva = READ_SYSREG(FAR_EL2);
> > > +
> > > + if ( iabt.s1ptw )
> > > + gpa = READ_SYSREG(HPFAR_EL2);
> > > + else
> >
> >
> > Can you not avoid the else case entirely by extending the if to
> cover
> > the other cases where HPFAR is explicitly valid? I can't be
> bothered to
> > go look right now but IIRC it included at least stage 2 access
> > permissions related failures, which would cover more xenaccess
> > scenarios, no?
> >
> >
> > Depending on the fault cause, we might. For permission faults, HPFAR
> > is only valid during s1ptw.. Given that the only check we do is for
> > permission faults and that's the only thing that cares about the API
> > anyway, we can put this entire block into the switch itself once the
> > fault check is already determined to be a permission fault.
>
> According to ARMv8 ARM HPFAR is valid for any of these:
> * A Translation or Access Flag fault on a stage 2 translation.
> * A stage 2 Address Size fault.
> * A fault on the stage 2 translation of an address accessed in a
> stage 1 translation table walk.
>
> I think what you are (correctly) saying is that it omits "a permission
> fault on a stage 2 translation", which is one of the cases which can
> occur under xenaccess. Which is shame :-(
>
> Ian.
>
Hm, what I recall is that it is valid for permission faults as well, but
only and exclusively during s1ptw.
Tamas
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