On 18/08/2017 06:02, Peter Xu wrote: >> The patch below is okay. However, vtd_switch_address_space is >> expensive, which is why I suggested the bottom half. > But still, shall we just do it this way? It looks cleaner. > > For the slowness (as I mentioned below), one thing to mention is that, > this fast path should even not be used when PT is enabled. When > "iommu=pt" is set, the IOMMU regions are off start from the very > beginning. In other words, this patch should only affect a very > corner use case, and to make sure that use case is safe, though it > brings the first IO of that use case slower. > > How do you think?
Sure, the patch you posted is fine by me. Paolo
