Re: [PATCH 0/3] Fix virtio-blk issue with SWIOTLB

[Joerg Roedel]

On Fri, Jan 11, 2019 at 11:29:31AM +0800, Jason Wang wrote:
> Just wonder if my understanding is correct IOMMU_PLATFORM must be set for
> all virtio devices under AMD-SEV guests?

Yes, that is correct. Emulated DMA can only happen on the SWIOTLB
aperture, because that memory is not encrypted. The guest bounces the
data then to its encrypted memory.

Regards,

	Joerg