On Mon, 19 Apr 2021, Rahul Singh wrote: > Hi Julien, > > > On 18 Apr 2021, at 6:48 pm, Julien Grall <jul...@xen.org> wrote: > > > > > > > > On 16/04/2021 17:41, Rahul Singh wrote: > >> Hi Julien > > > > Hi Rahul, > > > >>> On 16 Apr 2021, at 5:08 pm, Julien Grall <jul...@xen.org> wrote: > >>> > >>> > >>> > >>> On 16/04/2021 17:05, Rahul Singh wrote: > >>>>> On 16 Apr 2021, at 4:23 pm, Julien Grall <jul...@xen.org> wrote: > >>>>> > >>>>> > >>>>> > >>>>> On 16/04/2021 16:01, Rahul Singh wrote: > >>>>>> Hi Julien, > >>>>> > >>>>> Hi Rahul, > >>>>> > >>>>>>> On 16 Apr 2021, at 3:35 pm, Julien Grall <jul...@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. > >>>>> > >>>>> If we revert the patch, then it would not be possible to use the SMMU > >>>>> if two devices use the same stream-id. Is that correct? > >>>> No. If we revert the patch we can use the SMMU if two devices use the > >>>> same stream-id without any issue but each device will be in a separate > >>>> group.This is same behaviour before the code is merged. > >>> > >>> Ok. So there is no change in behavior. Good. Can you propose a commit > >>> message clarifying that? > >> Please have a look if it make sense. > >> xen/arm: smmuv1: Revert associating the group pointer with the S2CR > >> 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 with same stream-id. This issue is introduced by the below commit: > >> “0435784cc75dcfef3b5f59c29deb1dbb84265ddb:xen/arm: smmuv1: Intelligent SMR > >> allocation” > >> Reverting the code will not impact to use of SMMU if two devices use the > >> same stream-id but each device will be in a separate group. This is the > >> same > >> behaviour before the code is merged. > > > > Look good to me. Is this patch to be applied on top of Stefano's series? If > > not, is there going to be more clash? > > > > As per Stefano's mail he already tested his patch series on top of this > patch. I think this patch has to merged before Stefano’s patch series > Let Stefano also confirm that. > > I think there will be no more clashes.
Yes, this patch is to be committed *before* my series and I have already tested this patch alone and with my series on top. Both cases work fine.
