On Tue, Jul 23, 2024 at 10:09:13AM +0200, Eric Auger wrote: > > In pratice I don't know if such HW platforms even exist where different > > IOMMU > > instances present different value of dirty tracking, given that this is a > > IOMMU > > feature, rather than endpoint dependent. In x86 it's homogeneous, and > > likely on > > smmuv3 server too. There are indeed endpoint related features > > which may be
> on ARM you may have several SMMU instances. I do agree that the > likelyhood of those instances having heterogeneous dirty page > tracking support is low but well I don't know. Maybe we should add a > wanrning at least, later on if this case arises. >From what I understand about ARM IP there are additional system wide complexities to implement HTTU, it requires the SMMU have CPU coherent atomics, which means it has to use a different kind of bus.. Hopefully nobody does this, but still, I wouldn't assume the same consistency as x86... Jason
