From mboxrd@z Thu Jan  1 00:00:00 1970
From: Takuya Yoshikawa <takuya.yoshikawa@gmail.com>
Date: Mon, 18 Jun 2012 13:20:10 +0000
Subject: Re: [PATCH 3/4] KVM: MMU: Make kvm_handle_hva() handle range of addresses
Message-Id: <20120618222010.4b605f800956e3c7bf6bcd25@gmail.com>
List-Id: <kvm-ppc.vger.kernel.org>
References: <20120615203007.4f61bb17.yoshikawa.takuya@oss.ntt.co.jp>
	<20120615203230.2c577652.yoshikawa.takuya@oss.ntt.co.jp>
	<4FDF1AFE.4000607@redhat.com>
In-Reply-To: <4FDF1AFE.4000607@redhat.com>
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To: Avi Kivity <avi@redhat.com>
Cc: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>, mtosatti@redhat.com, agraf@suse.de, paulus@samba.org, aarcange@redhat.com, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, linux-kernel@vger.kernel.org

On Mon, 18 Jun 2012 15:11:42 +0300
Avi Kivity <avi@redhat.com> wrote:


> >  	kvm_for_each_memslot(memslot, slots) {
> > -		gfn_t gfn = hva_to_gfn(hva, memslot);
> > +		gfn_t gfn = hva_to_gfn(start_hva, memslot);
> > +		gfn_t end_gfn = hva_to_gfn(end_hva, memslot);
> 
> These will return random results which you then use in min/max later, no?

Yes, I will follow your advice: check-then-convert (or check-and-convert).

> > @@ -1212,7 +1218,9 @@ static int kvm_handle_hva(struct kvm *kvm, unsigned long hva,
> >  				rmapp = __gfn_to_rmap(gfn, j, memslot);
> >  				ret |= handler(kvm, rmapp, data);
> 
> Potential for improvement: don't do 512 iterations on same large page.
> 
> Something like
> 
>     if ((gfn ^ prev_gfn) & mask(level))
>         ret |= handler(...)
> 
> with clever selection of the first prev_gfn so it always matches (~gfn
> maybe).

Really nice.
I'm sure that will make this much faster!

Thanks,
	Takuya