Hi All: In some cases, the virtqueue could be backed by different devices. One example is that in the case of vDPA some parent may emualte virtqueue via vringh. In this case, it would be wrong if we stick with the physical DMA device for software emulated device, since there's no easy way for vringh to know about the hardware IOMMU mappings. So this series tries to introduce per virtqueue DMA device, then software virtqueues can utilize the transport specific method to assign appropirate DMA device. This fixes the crash of mlx5_vdpa + virtio_vdpa when platform IOMMU is enabled but not in the passthrough mode. The reason for the crash is that the virito_ring tries to map the control virtqueue into platform IOMMU but the vringh assumes a direct mapping (PA as IOVA). This is fixed by advetise the vDPA device that doesnt do DMA (without a DMA ops). So DMA API can go with the direct mapping then the vringh will be happy since mlx5_vdpa assuems a direct/identical mapping by default. Please review. Thanks Jason Wang (5): virtio_ring: per virtqueue dma device vdpa: introduce get_vq_dma_device() virtio-vdpa: support per vq dma device vdpa: set dma mask for vDPA device vdpa: mlx5: support per virtqueue dma device drivers/vdpa/mlx5/net/mlx5_vnet.c | 11 +++ drivers/vdpa/vdpa.c | 5 ++ drivers/virtio/virtio_ring.c | 133 +++++++++++++++++++++--------- drivers/virtio/virtio_vdpa.c | 13 ++- include/linux/vdpa.h | 6 ++ include/linux/virtio_ring.h | 16 ++++ 6 files changed, 141 insertions(+), 43 deletions(-) -- 2.25.1 _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
