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Re: [PATCH] xen/arm: smmuv1: Revert associating the group pointer with the S2CR
- To: Julien Grall <julien@xxxxxxx>
- From: Rahul Singh <Rahul.Singh@xxxxxxx>
- Date: Fri, 16 Apr 2021 15:01:26 +0000
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- Thread-topic: [PATCH] xen/arm: smmuv1: Revert associating the group pointer with the S2CR
Hi Julien,
> On 16 Apr 2021, at 3:35 pm, Julien Grall <julien@xxxxxxx> wrote:
>
> Hi,
>
> On 16/04/2021 12:25, Rahul Singh wrote:
>> Revert the code that associates the group pointer with the S2CR as this
>> code causing an issue when the SMMU device has more than one master
>> device.
>
> It is not clear to me why this change was first added. Are we missing any
> feature when reverting it?
This feature was added when we backported the code from Linux to fix the stream
match conflict issue
as part of commit "xen/arm: smmuv1: Intelligent SMR allocation”.
This is an extra feature added to allocate IOMMU group based on stream-id. If
two device has the
same stream-id then we assign those devices to the same group. This code was
removed from Linux
later point in time when IOMMU group handling is done by Linux code not by a
specific IOMMU driver.
Therefore I think it is ok revert the code.
>
>> This code is merged with the commit "xen/arm: smmuv1: Intelligent
>> SMR allocation”.
>
> This wants a fixes tag. Can be added on commit if there is nothing else to
> change.
Yes. That will be great. This fixes the commit
“0435784cc75dcfef3b5f59c29deb1dbb84265ddb:xen/arm: smmuv1: Intelligent SMR
allocation”
Regards,
Rahul
>
> Cheers,
>
> --
> Julien Grall
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