On Fri, 21 Feb 2020 11:41:57 +0800
Jason Wang [off-list ref] wrote:

quoted

I *think* what you are suggesting here is that virtio devices that
have !F_IOMMU_PLATFORM should have their dma_ops set up so that the
DMA API treats IOVA==PA, which will satisfy what the device expects.  

Can this work for swiotlb?

It works on s390. I guess it would be the responsibility of however
provides the dma ops for the virtio device to ensure that if 
!F_IOMMU_PLATFORM the addresses are GPA like *mandated* by the VIRTIO
specification.

Regards,
Halil