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From: Peter Maydell <peter.maydell@linaro.org>
Date: Thu, 9 Apr 2015 11:43:53 +0100
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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: Paolo Bonzini <pbonzini@redhat.com>
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 9 April 2015 at 11:21, Paolo Bonzini <pbonzini@redhat.com> wrote:
>
>
> On 09/04/2015 12:14, Peter Maydell wrote:
>> On 9 April 2015 at 10:59, Edgar E. Iglesias <edgar.iglesias@gmail.com> wrote:
>>> > On Tue, Apr 07, 2015 at 09:09:52PM +0100, Peter Maydell wrote:
>>>> >> Make address_space_rw take transaction attributes, rather
>>>> >> than always using the 'unspecified' attributes.
>>> >
>>> > Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
>>> >
>>> > I guess that we eventually will need to convert the dma_
>>> > functions?
>> Probably, though I'm not clear what they bring to the party
>> that the basic address_space_* functions don't (part of why
>> I left them alone).
>
> 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...)

thanks
-- PMM