Re: [PATCH 0/7] Do not read from descriptor ring

[Andy Lutomirski]

On 6/3/21 10:53 PM, Jason Wang wrote:
> Hi:
> 
> The virtio driver should not trust the device. This beame more urgent
> for the case of encrtpyed VM or VDUSE[1]. In both cases, technology
> like swiotlb/IOMMU is used to prevent the poking/mangling of memory
> from the device. But this is not sufficient since current virtio
> driver may trust what is stored in the descriptor table (coherent
> mapping) for performing the DMA operations like unmap and bounce so
> the device may choose to utilize the behaviour of swiotlb to perform
> attacks[2].

Based on a quick skim, this looks entirely reasonable to me.

(I'm not a virtio maintainer or expert.  I got my hands very dirty with
virtio once dealing with the DMA mess, but that's about it.)

--Andy