Re: swapping with MMU Notifiers V2

Andrea Arcangeli
2008-01-29T17:54:20Z

On Tue, Jan 29, 2008 at 05:35:34PM +0100, Carsten Otte wrote:
> Avi Kivity wrote:
> > Every arch except s390 needs it. An ugly #ifndef
> > CONFIG_KVM_HARDWARE_TLB_SYNC is preferred to duplicating the code.
> BTW, from reading AMDs spec I don't expect NPT to need this vehicle

By your conclusion I suppose you thought NPT maps guest physical to
host virtual. If it was the case the cpu would to walk three layer of
pagetables (each layer is an arrow): guest virtual -> guest physical
-> host virtual -> host physical. Instead it's just guest virtual ->
guest physical -> host physical. Or even less for shadow: guest
virtual -> host physical, which is why shadow should be faster for
number crunching still (and definitely slower for dbms).