On Sun, Aug 05, 2018 at 11:10:15AM +1000, Benjamin Herrenschmidt wrote: > - One you have rejected, which is to have a way for "no-iommu" virtio > (which still doesn't use an iommu on the qemu side and doesn't need > to), to be forced to use some custom DMA ops on the VM side. > > - One, which sadly has more overhead and will require modifying more > pieces of the puzzle, which is to make qemu uses an emulated iommu. > Once we make qemu do that, we can then layer swiotlb on top of the > emulated iommu on the guest side, and pass that as dma_ops to virtio. Or number three: have a a virtio feature bit that tells the VM to use whatever dma ops the platform thinks are appropinquate for the bus it pretends to be on. Then set a dma-range that is limited to your secure memory range (if you really need it to be runtime enabled only after a device reset that rescans) and use the normal dma mapping code to bounce buffer. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
