Re: [RFC] virtio: Use DMA MAP API for devices without an IOMMU

From: Anshuman Khandual
Date: Thu Apr 05 2018 - 10:40:06 EST

On 04/05/2018 04:26 PM, Anshuman Khandual wrote:
> There are certian platforms which would like to use SWIOTLB based DMA API
> for bouncing purpose without actually requiring an IOMMU back end. But the
> virtio core does not allow such mechanism. Right now DMA MAP API is only
> selected for devices which have an IOMMU and then the QEMU/host back end
> will process all incoming SG buffer addresses as IOVA instead of simple
> GPA which is the case for simple bounce buffers after being processed with
> SWIOTLB API. To enable this usage, it introduces an architecture specific
> function which will just make virtio core front end select DMA operations
> structure.
> Signed-off-by: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>

+ "Michael S. Tsirkin" <mst@xxxxxxxxxx>