Re: [PATCH 3/4] KVM: MMU: Make kvm_handle_hva() handle range of addresses

[Takuya Yoshikawa <takuya.yoshikawa@gmail.com>]

I should have read this before sending v2...

On Thu, 21 Jun 2012 11:24:59 +0300
Avi Kivity <avi@redhat.com> wrote:

> > 1. Separate rmap_pde from lpage_info->write_count and
> >    make this a simple array. (I once tried this.)
> > 
> 
> This has the potential to increase cache misses, but I don't think it's
> a killer.  The separation can simplify other things as well.

Yes, I think so too.

IIRC, write_count and rmap_pde are not used together so often.

> > 2. Use gfn_to_index() and loop over rmap array:

...

> >   /* main part */
> >   for each level {
> >       rmapp = __gfn_to_rmap(gfn_start, level, memslot);
> >       for (idx = gfn_to_index(gfn_start, memslot->base_gfn, level);
> >            idx < gfn_to_index(gfn_end, memslot->base_gfn, level); idx++) {
> >               ...
> >           /* loop over rmap array */
> >           ret |= handler(kvm, rmapp + idx, data);
> >       }
> >   }
> > 
> 
> Probably want idx <= gfn_to_index(gfn_end-1, ...) otherwise we fail on
> small slots.

I was thinking the same thing when making v2.
But I will check the boundary condition again.

(mmu_notifier + memslot + lpage + rmap...) * alignment...
Very confusing.

Thanks,
	Takuya