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

["Tian, Kevin" <kevin.tian@xxxxxxxxx>]

>From: Tristan Gingold [mailto:Tristan.Gingold@xxxxxxxx]
>> >> >> 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.
>

For auto translated mode, guest page table is not changed and only p->m 
relationship is changed. So guest doesn't issue ptc, and current 
para-driver explicitly depends on grant table ops to purge gva->m 
mapping. We just follow that model and no need to change it.

Thanks
Kevin

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