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From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [PATCH 5/5] virtio: Add bounce DMA ops
Date: Thu, 30 Apr 2020 11:20:08 -0400
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: tsoni@codeaurora.org, virtio-dev@lists.oasis-open.org, will@kernel.org, jan.kiszka@siemens.com, Srivatsa Vaddagiri <vatsa@codeaurora.org>, christoffer.dall@arm.com, pratikp@codeaurora.org, virtualization@lists.linux-foundation.org, iommu@lists.linux-foundation.org, stefano.stabellini@xilinx.com, linux-kernel@vger.kernel.org, Lu Baolu <baolu.lu@linux.intel.com>
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On Wed, Apr 29, 2020 at 06:20:48AM -0400, Michael S. Tsirkin wrote:
> 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.

There are two DMA pools code in Linux already - the TTM one for graphics
and the mm/dmapool.c - could those be used instead? Or augmented at least?