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From: Benjamin Herrenschmidt <benh@au1.ibm.com>
Date: Mon, 27 Feb 2012 11:25:55 +1100
In-Reply-To: <20120227001605.GD3433@truffala.fritz.box>
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Subject: Re: [Qemu-devel] [PATCH 6/6] kvm: Fix dirty tracking with large
 kernel page size
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To: David Gibson <david@gibson.dropbear.id.au>
Cc: Blue Swirl <blauwirbel@gmail.com>, Marcelo Tossatti <mtossatti@redhat.com>, qemu-devel@nongnu.org, anthony@codemonkey.ws, Avi Kivity <avi@redhat.com>

On Mon, 2012-02-27 at 11:16 +1100, David Gibson wrote:
> > > If the kernel page size is larger than TARGET_PAGE_SIZE, which
> > > happens for example on ppc64 with kernels compiled for 64K pages,
> > > the dirty tracking doesn't work.
> > 
> > I think a better solution would be to push this to memory API and
> > underlying exec.c dirty tracking so that they use the same page size
> > as kernel (only in this KVM case, in general dirty tracking should
> > match TARGET_PAGE_SIZE granularity). 

That sounds horrible... you propose a -MUCH- more invasive change to a
nasty & complex core piece of code to deal with what is fixed by a
2-liner patch ?

Cheers,
Ben.