From mboxrd@z Thu Jan  1 00:00:00 1970
From: Julien Grall <julien.grall@linaro.org>
Subject: Re: [PATCH v2 10/12] xen/iommu: smmu: Check for
 duplicate stream IDs when registering master devices
Date: Tue, 27 Jan 2015 17:33:56 +0000
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To: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: ian.campbell@citrix.com, tim@xen.org, Andreas Herrmann <herrmann.der.user@googlemail.com>, stefano.stabellini@citrix.com, Andreas Herrmann <andreas.herrmann@calxeda.com>, xen-devel@lists.xenproject.org
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On 27/01/15 17:02, Stefano Stabellini wrote:
> On Tue, 27 Jan 2015, Julien Grall wrote:
>> On 27/01/15 16:30, Stefano Stabellini wrote:
>>> On Fri, 16 Jan 2015, Julien Grall wrote:
>>>> From: Andreas Herrmann <andreas.herrmann@calxeda.com>
>>>>
>>>> If DT information lists one stream ID twice for the master devices of
>>>> an SMMU this can cause a multi match when stream ID matching is used.
>>>> For stream ID indexing this might trigger an overwrite of an S2CR that
>>>> is already in use.
>>>>
>>>> So better check for duplicates when DT information is parsed.
>>>>
>>>> Taken from the linux ML:
>>>> http://lists.infradead.org/pipermail/linux-arm-kernel/2014-January/226099.html
>>>>
>>>> Cc: Andreas Herrmann <herrmann.der.user@googlemail.com>
>>>> Signed-off-by: Andreas Herrmann <andreas.herrmann@calxeda.com>
>>>> Signed-off-by: Julien Grall <julien.grall@linaro.org>
>>>
>>> Why didn't you just take a more recent version of the Linux smmu driver?
>>
>> The SMMU driver very is recent (see commit in the previous patch)...
>> Just this patch has never reached upstream.
> 
> That is not good. It might be worth to wait for it to go upstream.

The patch was sent one year ago. Just before Calxeda was shutdown.

This is a requirement for the following patch. Do you think the other
patch should be upstream to Linux before? If so, Calxeda server won't be
able to use properly SMMU.

Even though the server will never be used, I do all my SMMU development
on it.

FWIW, we use already use the 2 patches in the current SMMU drivers.

Regards,

-- 
Julien Grall