On Mon, Jul 22, 2024 at 08:19:23PM +1000, Alexey Kardashevskiy wrote: > If there is vIOMMU, then the driver in the VM can decide whether it wants > private or shared memory for DMA, pass that new flag to dma_map() and 1) > have DMA memory allocated from the private pool (== no page state changes) > and 2) have C-bit set in the vIOMMU page table (which is in the VM memory). Not all HW supports a flow like that. > My V1 says "all IOVA below X are private and above - shared" (which is a hw > knob in absence of vIOMMU) and I set the X to all '1's just to mark it all > private. Is that portable to other implementations? Jason
