On Sat, Aug 10, 2019 at 11:46:21PM -0700, Ram Pai wrote: > If the hypervisor (hardware for hw virtio devices) does not mandate a > DMA API, why is it illegal for the driver to request, special handling > of its i/o buffers? Why are we associating this special handling to > always mean, some DMA address translation? Can't there be > any other kind of special handling needs, that has nothing to do with > DMA address translation?
I don't think it is illegal per se. It is however completely broken if we do that decision on a system weide scale rather than properly requesting it through a per-device flag in the normal virtio framework.
