On Tue, May 19, 2020 at 07:54:56PM +0200, Jean-Philippe Brucker wrote: > If the SMMU supports it and the kernel was built with HTTU support, > enable hardware update of access and dirty flags. This is essential for > shared page tables, to reduce the number of access faults on the fault > queue. Normal DMA with io-pgtables doesn't currently use the access or > dirty flags. > > We can enable HTTU even if CPUs don't support it, because the kernel > always checks for HW dirty bit and updates the PTE flags atomically. > > Signed-off-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx> > --- > drivers/iommu/arm-smmu-v3.c | 24 +++++++++++++++++++++++- > 1 file changed, 23 insertions(+), 1 deletion(-) How does this work if the SMMU isn't cache coherent? I'm guessing we don't want to enable any SVA stuff in that case, but I couldn't spot where that was being enforced. Did I just miss it? Will
