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Re: [Xen-devel] Re: [Qemu-devel] Recursion in cpu_physical_memory_rw

To: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] Re: [Qemu-devel] Recursion in cpu_physical_memory_rw
From: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Date: Wed, 15 Nov 2006 22:12:26 +1100
Cc: Xen Development Mailing List <xen-devel@xxxxxxxxxxxxxxxxxxx>, Paul Brook <paul@xxxxxxxxxxxxxxxx>, qemu-devel@xxxxxxxxxx
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On Wed, Nov 15, 2006 at 07:55:48AM +0000, Keir Fraser wrote:
>
> > I'm not suggesting that we change all existing users of cpu_physical_*
> > to a new interface that only accessed RAM.  However, for cases where it
> > is obvious that only system RAM is intended (e.g., rtl8139), it makes
> > sense to bypass MMIO handlers.
> 
> Could we add a recursion counter to the memory-access functions, and bail if
> it reaches some limit?

Yes that would work too.  However, chips such as rtl8139 should never
do MMIO in this case (the real hardware would never allow that to occur)
so we should do that accordingly.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
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