On Wed, Oct 21, 2020 at 01:03:22PM -0300, Jason Gunthorpe wrote: > Oh, interesting.. Yes the issue is no userspace DMA stuff uses the DMA > API correctly (because it is in userspace) > > So SWIOTLB tricks don't work, I wish the dma_map could fail for these > situations Userspace DMA by definition also does not use dma_map..