RE: [Xen-devel] PV guest + shadow paging

["Nakajima, Jun" <jun.nakajima@xxxxxxxxx>]

Jeremy Fitzhardinge wrote:
> Keir Fraser wrote:
> > On 24/10/07 11:00, "Jeremy Fitzhardinge" <jeremy@xxxxxxxx> wrote:
> > 
> > 
> > > Tim Deegan wrote:
> > > 
> > > > The joy of NPT(VMI?)/EPT is that you don't need shadow
pagetables at
> > > > all. :) 
> > > > 
> > > > 
> > > Sure, but from a guest interface perspective they look the same.
> > > 
> > 
> > Would you want to take advantage of NPT/EPT once you've pv'ed your
mmu
> > interfaces? 
> > 
> 
> I think so.  NPT/EPT would seem to have all the advantages of shadow
> paging and direct paging without the disadvantages.  We would avoid
> taking faults/hypercalls on pagetable updates, and have the secondary
> benefit of not needing to worry about page permissions on pagetables,
> making it easier to use superpages for the kernel and in general.
> Perhaps the initial implementations will be sufficiently poor that it
> isn't worth doing now, but I think it will in time.
> 
>     J

Well, then you need to run those in HVM domains ;-)


Jun
---
Intel Open Source Technology Center

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