Re: [PATCH 5/5] virtio: Add bounce DMA ops

Srivatsa Vaddagiri
2020-04-29T10:35:02Z

* Michael S. Tsirkin <mst@redhat.com> [2020-04-29 06:20:48]:

> On Wed, Apr 29, 2020 at 03:39:53PM +0530, Srivatsa Vaddagiri wrote:
> > That would still not work I think where swiotlb is used for pass-thr devices
> > (when private memory is fine) as well as virtio devices (when shared memory is
> > required).
>
> So that is a separate question. When there are multiple untrusted
> devices, at the moment it looks like a single bounce buffer is used.
>
> Which to me seems like a security problem, I think we should protect
> untrusted devices from each other.

I think as first step, let me see if we can make swiotlb driver accept a target
memory segment as its working area. That may suffice our needs I think. A
subsequent step could be to make swiotlb driver recognize multiple pools.

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