From: Stefano Stabellini <sstabellini@kernel.org>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: tsoni@codeaurora.org, virtio-dev@lists.oasis-open.org,
konrad.wilk@oracle.com, jan.kiszka@siemens.com,
jasowang@redhat.com, Srivatsa Vaddagiri <vatsa@codeaurora.org>,
christoffer.dall@arm.com,
virtualization@lists.linux-foundation.org,
alex.bennee@linaro.org, iommu@lists.linux-foundation.org,
stefano.stabellini@xilinx.com, will@kernel.org,
linux-kernel@vger.kernel.org, pratikp@codeaurora.org
Subject: Re: [PATCH 5/5] virtio: Add bounce DMA ops
Date: Tue, 28 Apr 2020 16:04:34 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.21.2004281556180.29217@sstabellini-ThinkPad-T480s> (raw)
In-Reply-To: <20200428163448-mutt-send-email-mst@kernel.org>
On Tue, 28 Apr 2020, Michael S. Tsirkin wrote:
> On Tue, Apr 28, 2020 at 11:19:52PM +0530, Srivatsa Vaddagiri wrote:
> > * Michael S. Tsirkin <mst@redhat.com> [2020-04-28 12:17:57]:
> >
> > > Okay, but how is all this virtio specific? For example, why not allow
> > > separate swiotlbs for any type of device?
> > > For example, this might make sense if a given device is from a
> > > different, less trusted vendor.
> >
> > Is swiotlb commonly used for multiple devices that may be on different trust
> > boundaries (and not behind a hardware iommu)?
The trust boundary is not a good way of describing the scenario and I
think it leads to miscommunication.
A better way to describe the scenario would be that the device can only
DMA to/from a small reserved-memory region advertised on device tree.
Do we have other instances of devices that can only DMA to/from very
specific and non-configurable address ranges? If so, this series could
follow their example.
> Even a hardware iommu does not imply a 100% security from malicious
> hardware. First lots of people use iommu=pt for performance reasons.
> Second even without pt, unmaps are often batched, and sub-page buffers
> might be used for DMA, so we are not 100% protected at all times.
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next prev parent reply other threads:[~2020-04-28 23:04 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-28 11:39 [PATCH 0/5] virtio on Type-1 hypervisor Srivatsa Vaddagiri
2020-04-28 11:39 ` [PATCH 1/5] swiotlb: Introduce concept of swiotlb_pool Srivatsa Vaddagiri
2020-04-29 0:31 ` kbuild test robot
2020-04-28 11:39 ` [PATCH 2/5] swiotlb: Allow for non-linear mapping between paddr and vaddr Srivatsa Vaddagiri
2020-04-28 11:39 ` [PATCH 3/5] swiotlb: Add alloc and free APIs Srivatsa Vaddagiri
2020-04-30 4:18 ` kbuild test robot
2020-04-28 11:39 ` [PATCH 4/5] swiotlb: Add API to register new pool Srivatsa Vaddagiri
2020-04-28 11:39 ` [PATCH 5/5] virtio: Add bounce DMA ops Srivatsa Vaddagiri
2020-04-28 16:17 ` Michael S. Tsirkin
2020-04-28 17:49 ` Srivatsa Vaddagiri
2020-04-28 20:41 ` Michael S. Tsirkin
2020-04-28 23:04 ` Stefano Stabellini [this message]
2020-04-29 4:09 ` Srivatsa Vaddagiri
2020-04-29 2:22 ` Lu Baolu
2020-04-29 4:57 ` Michael S. Tsirkin
2020-04-29 5:42 ` Lu Baolu
2020-04-29 6:50 ` Michael S. Tsirkin
2020-04-29 7:01 ` Lu Baolu
2020-04-29 9:44 ` Srivatsa Vaddagiri
2020-04-29 9:52 ` Michael S. Tsirkin
2020-04-29 10:09 ` Srivatsa Vaddagiri
2020-04-29 10:20 ` Michael S. Tsirkin
2020-04-29 10:26 ` Jan Kiszka
2020-04-29 10:45 ` Michael S. Tsirkin
2020-04-29 10:55 ` [virtio-dev] " Jan Kiszka
2020-04-29 10:34 ` Srivatsa Vaddagiri
2020-04-30 15:20 ` Konrad Rzeszutek Wilk
2020-04-29 3:35 ` Srivatsa Vaddagiri
2020-04-28 21:35 ` kbuild test robot
2020-04-28 22:18 ` kbuild test robot
2020-04-28 22:53 ` Stefano Stabellini
2020-04-29 21:06 ` kbuild test robot
2020-04-29 21:06 ` [RFC PATCH] virtio: virtio_pool can be static kbuild test robot
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