From: Rahul Singh <Rahul.Singh@arm.com>
To: Julien Grall <julien@xen.org>
Cc: xen-devel <xen-devel@lists.xenproject.org>,
Bertrand Marquis <Bertrand.Marquis@arm.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
Subject: Re: [PATCH] xen/arm: smmuv1: Revert associating the group pointer with the S2CR
Date: Fri, 16 Apr 2021 15:01:26 +0000 [thread overview]
Message-ID: <E2FE265F-B7A4-45C3-BA9C-3EF9109F8B5E@arm.com> (raw)
In-Reply-To: <6e75d112-6cc1-4b7c-9751-4064b3250dbf@xen.org>
Hi Julien,
> On 16 Apr 2021, at 3:35 pm, Julien Grall <julien@xen.org> 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
next prev parent reply other threads:[~2021-04-16 15:02 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-16 11:25 [PATCH] xen/arm: smmuv1: Revert associating the group pointer with the S2CR Rahul Singh
2021-04-16 14:28 ` Bertrand Marquis
2021-04-16 14:35 ` Julien Grall
2021-04-16 15:01 ` Rahul Singh [this message]
2021-04-16 15:23 ` Julien Grall
2021-04-16 16:05 ` Rahul Singh
2021-04-16 16:08 ` Julien Grall
2021-04-16 16:41 ` Rahul Singh
2021-04-18 17:48 ` Julien Grall
2021-04-19 11:02 ` Rahul Singh
2021-04-19 16:21 ` Stefano Stabellini
2021-04-20 12:39 ` Julien Grall
2021-04-20 13:52 ` Rahul Singh
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