Re: [Xen-ia64-devel] PATCH: cleanup of tlbflush

[Tristan Gingold <Tristan.Gingold@xxxxxxxx>]

Le Mercredi 10 Mai 2006 14:37, Tian, Kevin a écrit :
> From: Tristan Gingold [mailto:Tristan.Gingold@xxxxxxxx]
>
> >Sent: 2006年5月10日 19:57
> >
> >Le Mercredi 10 Mai 2006 13:38, Tian, Kevin a écrit :
> >> From: Tristan Gingold [mailto:Tristan.Gingold@xxxxxxxx]
> >>
> >> >Sent: 2006年5月10日 18:47
> >> >
> >> >> I see your concern about flush efficiency. However we still need set
> >> >> necessary mask bits for correctness, right?
> >> >
> >> >Not yet, because pages are not transfered.
> >>
> >> It's not specific to page flipping. Simple page sharing also has same
> >> problem.
> >
> >No really.  Page sharing is only from domU to dom0.  Thus, if we trust
> >dom0 we
> >don't need to flush all the tlb.
>
> No, even for dom0, the mapped va may be accessed on several vcpus
> and thus you have to flush all related TLBs. On this point, there's no
> need to differentiate dom0 or domU. 
We can trust dom0.  It flushes it correctly with ptc.l or ptc.ga.

>Simple thing is to flush based on
> domain_dirty_cpumask upon unmap request.

Tristan.

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