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Date: Thu, 09 Apr 2015 13:40:15 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 06/14] exec.c: Make address_space_rw take
 transaction attributes
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: Peter Crosthwaite <peter.crosthwaite@xilinx.com>, Patch Tracking <patches@linaro.org>, QEMU Developers <qemu-devel@nongnu.org>, Greg Bellows <greg.bellows@linaro.org>, "Edgar E. Iglesias" <edgar.iglesias@gmail.com>, =?UTF-8?B?QWxleCBCZW5uw6ll?= <alex.bennee@linaro.org>, Richard Henderson <rth@twiddle.net>



On 09/04/2015 12:43, Peter Maydell wrote:
> > At this point, some memory barriers, basically.
>
> So what distinguishes a device that needs the memory barriers
> and does its accesses via dma_* from a device that doesn't and
> uses address_space_* or ld/st*_phys ? (Or for that matter a
> non-device that does memory accesses...)

I don't know exactly, I didn't follow the discussion very much back
then.  The memory barriers were fixing PPC bugs; PCI devices definitely
need them.

Paolo