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RE: [Xen-ia64-devel] PATCH: rewrite vcpu_get_psr
Quoting "Xu, Anthony" <anthony.xu@xxxxxxxxx>:
> >Tristan Gingold
> >Sent: 2007Äê5ÔÂ11ÈÕ 13:23
> >To: Alex Williamson
> >Cc: Xen-ia64-devel
> >Subject: Re: [Xen-ia64-devel] PATCH: rewrite vcpu_get_psr
> >> Unfortunately...
> >It's a little bit puzzling. I didn't think the performace of mov =psr.l was
> >to important!
> + if (!PSCB(vcpu, metaphysical_mode))
> + newpsr.i64 |= IA64_PSR_DT | IA64_PSR_RT | IA64_PSR_IT;
> - if (PSCB(vcpu, metaphysical_mode))
> - newpsr.dt = 0;
> Above old code would be translated to
> if (PSCB(vcpu, metaphysical_mode))
> newpsr.i64 &= ~IA64_PSR_DT;
I seriously think the old code was wrong (more precisely incorrect).
I have to re-read Dan's paper and linux code, but in PV mode we only correctly
(the same should be true for VTi BTW and incidently we can
easily write OS which cannot be virtualized by VTi!)
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