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Date: Mon, 27 Feb 2012 11:16:05 +1100
From: David Gibson <david@gibson.dropbear.id.au>
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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: Blue Swirl <blauwirbel@gmail.com>
Cc: Benjamin Herrenschmidt <benh@au.ibm.com>, Marcelo Tossatti <mtossatti@redhat.com>, qemu-devel@nongnu.org, anthony@codemonkey.ws, Avi Kivity <avi@redhat.com>

On Sun, Feb 26, 2012 at 09:41:17PM +0000, Blue Swirl wrote:
> On Fri, Feb 24, 2012 at 00:23, David Gibson <david@gibson.dropbear.id.au> wrote:
> > From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> >
> > 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).

I'm having trouble reconciling the two parts of this comment.  If it
should be in terms of TARGET_PAGE_SIZE generally, why _not_ keep it
that way always, and just do a fixup when we have to send the data to
the host kernel in terms of host kernel page size?

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson