[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-devel] [PATCH] [VTD] Separate VT-d page table from P2M table
> If EPT supports 2MB page, we need separate VT-d table to let them work > together. Are you saying that the VT-d 2MB page format is different from the EPT 2MB page format? Or that VTd does not support 2MB pages? Ian > What's more, sharing makes coupling between VT-d page table > and p2m table. In case VT-d spec changes or p2m structure changes, > shared table will be broken. > Randy (Weidong) > > Keir Fraser wrote: > > What are the tradeoffs? One obvious tradeoff is that separate tables > > doubles the memory overhead. What are the advantages of separate > > tables? I believe currently we share the pagetables (right?). If so, > > why would we even consider moving to separate tables? > > > > -- Keir > > > > On 22/4/08 10:34, "Han, Weidong" <weidong.han@xxxxxxxxx> wrote: > > > >> Separate VT-d page table is by default. Shared VT-d page table may > be > >> easy and good in some cases. So we let them co-exist now. If shared > >> VT-d page table is not necessary and useless, we can remove it > >> easily in future. > >> > >> Randy (weidong) > >> > >> Keir Fraser wrote: > >>> On 22/4/08 09:36, "Han, Weidong" <weidong.han@xxxxxxxxx> wrote: > >>> > >>>> Currently VT-d page table shares with P2M table, this patch > >>>> supports separate VT-d page table. 1) add an option (vtd_share) to > >>>> control whether VT-d page table shares with P2M table or not. > >>> > >>> Why? Is this just another option that noone will understand. > >>> > >>> -- Keir > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@xxxxxxxxxxxxxxxxxxx > http://lists.xensource.com/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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