Hi Tristan.
+ /* Purge tc entry.
+ Can we do this directly ? Well, this is just a
+ single atomic write. */
+ vcpu_purge_tr_entry(&PSCBX(v,dtlb));
+ vcpu_purge_tr_entry(&PSCBX(v,itlb));
These aren't SMP-safe because dtlb isn't read atomically.
>From vcpu_translate()
#define vcpu_match_tr_entry(_trp,_ifa,_rid) \
((_trp->p && (_trp->rid==_rid) && (_ifa >= _trp->vadr) && \
(_ifa < (_trp->vadr + (1L<< _trp->ps)) - 1)))
trp = &vcpu->arch.dtlb;
if (/* is_data && */ vcpu_match_tr_entry(trp,address,rid)) {
<<<<<<<<<<<<If other processor executes
vcpu_purge_tr_entry(&PSCBX(v,dtlb)) here,
then a disaster will happen >>>>>>>>>>>>>>>>
if (vcpu->domain==dom0 && !in_tpa) *pteval = trp->page_flags;
else *pteval = vcpu->arch.dtlb_pte;
*itir = trp->itir;
dtlb_translate_count++;
return IA64_NO_FAULT;
}
In fact it's more subtle because of memory ordering.
thanks.
On Mon, Mar 27, 2006 at 02:15:27PM +0100, Tristan Gingold wrote:
> Le Lundi 27 Mars 2006 15:07, Alex Williamson a écrit :
> > On Mon, 2006-03-27 at 13:53 +0100, Tristan Gingold wrote:
> > > Hi,
> > >
> > > this is a very simple extension of vcpu_ptc_ga to support SMP-g.
> > > The implementation could be optimized.
> >
> > Hi Tristan,
> >
> > There's no patch attached, please resend. Thanks,
> >
> > Alex
> Sorry.
> Here it comes.
>
> Tristan.
>
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--
yamahata
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