On Fri, 2009-10-09 at 13:57 -0700, Hollis Blanchard wrote:
> > +#ifdef CONFIG_PPC64
> > +#ifdef DEBUG_EMUL
> > + printk(KERN_INFO "mtDEC: %x\n", vcpu->arch.dec);
> > +#endif
> > + /* POWER4+ triggers a dec interrupt if the value is < 0 */
> > + if (vcpu->arch.dec & 0x80000000) {
> > + del_timer(&vcpu->arch.dec_timer);
> > + kvmppc_core_queue_dec(vcpu);
> > + }
> > + else if (true) {
> > +#else
> > if (vcpu->arch.tcr & TCR_DIE) {
> > +#endif
> > /* The decrementer ticks at the same rate as the timebase, so
> > * that's how we convert the guest DEC value to the number of
> > * host ticks. */
>
> Ifdefs through the middle of control syntax makes my head hurt. :)
Note that your original BookE DEC emulation looks fishy :-)
I may have missed something in your code... but I don't think it
emulates the expected HW behaviour:
Basically, when the BookE DEC hits the 1 -> 0 transition it latches an
event in TSE:DIS always, whether TCR:DIE is set or not. If DIE is not
set, the interrupt is sent. It will then stop counting if auto-reload
isn't enabled.
That means that if TSR:DIS is set from a previous event while TCR:DIE is
clear, then setting TCR:DIE (with MSR:EE enabled of course) will trigger
a DEC interrupt on BookE.
The BookE DEC interrupt is basically a level sensitive thing sourced
from to (TSR:DIS && TCR:DIE), and TSR:DIS remains set until explicitely
cleared.
Cheers,
Ben.
--
To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
