On Tue, Jul 01, 2025 at 09:13:52AM +0800, Jason Wang wrote:
> Hi all:
>
> Virtio used to be coupled with DMA API. This works fine for the device
> that do real DMA but not the others. For example, VDUSE nees to craft
> with DMA API in order to let the virtio-vdpa driver to work.
>
> This series tries to solve this issue by introducing the mapping API
> in the virtio core. So transport like vDPA can implement their own
> mapping logic without the need to hack with DMA API. The mapping API
> are abstracted with a new map operations in order to be re-used by
> transprot or device. So device like VDUSE can implement its own
> mapping loigc.
>
> Please review.
>
> Thanks
Cost of all this extra indirection? Especially on systems with
software spectre mitigations/retpoline enabled.
> Jason Wang (9):
> virtio_ring: constify virtqueue pointer for DMA helpers
> virtio_ring: switch to use dma_{map|unmap}_page()
> virtio: rename dma helpers
> virtio: rename dma_dev to map_token
> virtio_ring: rename dma_handle to map_handle
> virtio: introduce map ops in virtio core
> vdpa: rename dma_dev to map_token
> vdpa: introduce map ops
> vduse: switch to use virtio map API instead of DMA API
>
> drivers/net/virtio_net.c | 32 +-
> drivers/vdpa/alibaba/eni_vdpa.c | 5 +-
> drivers/vdpa/ifcvf/ifcvf_main.c | 5 +-
> drivers/vdpa/octeon_ep/octep_vdpa_main.c | 6 +-
> drivers/vdpa/pds/vdpa_dev.c | 3 +-
> drivers/vdpa/solidrun/snet_main.c | 4 +-
> drivers/vdpa/vdpa.c | 5 +-
> drivers/vdpa/vdpa_sim/vdpa_sim.c | 4 +-
> drivers/vdpa/vdpa_user/iova_domain.c | 8 +-
> drivers/vdpa/vdpa_user/iova_domain.h | 5 +-
> drivers/vdpa/vdpa_user/vduse_dev.c | 34 +-
> drivers/vdpa/virtio_pci/vp_vdpa.c | 5 +-
> drivers/vhost/vdpa.c | 11 +-
> drivers/virtio/virtio_ring.c | 440 ++++++++++++++---------
> drivers/virtio/virtio_vdpa.c | 15 +-
> include/linux/vdpa.h | 22 +-
> include/linux/virtio.h | 36 +-
> include/linux/virtio_config.h | 68 ++++
> include/linux/virtio_ring.h | 6 +-
> 19 files changed, 476 insertions(+), 238 deletions(-)
>
> --
> 2.34.1
