On Fri, 2018-06-15 at 02:16 -0700, Christoph Hellwig wrote: > On Wed, Jun 13, 2018 at 11:11:01PM +1000, Benjamin Herrenschmidt wrote: > > Actually ... the stuff in lib/dma-direct.c seems to be just it, no ? > > > > There's no cache flushing and there's no architecture hooks that I can > > see other than the AMD security stuff which is probably fine. > > > > Or am I missing something ? > > You are missing the __phys_to_dma arch hook that allows architectures > to adjust the dma address. Various systems have offsets, or even > multiple banks with different offsets there. Most of them don't > use the dma-direct code yet (working on it), but there are a few > examples in the tree already.
Ok and on those systems, qemu will bypass said offset ? Maybe we could just create a device DMA "flag" or (or use the attributes) to instruct dma-direct to not use that for legacy virtio ? Cheers, Ben. _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
