From: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
To: Jerome Glisse <jglisse@redhat.com>, Kenneth Lee <liguozhu@hisilicon.com>
Cc: Kenneth Lee <nek.in.cn@gmail.com>,
Alex Williamson <alex.williamson@redhat.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
kvm@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-doc@vger.kernel.org,
Sanjay Kumar <sanjay.k.kumar@intel.com>,
Hao Fang <fanghao11@huawei.com>,
linux-kernel@vger.kernel.org, linuxarm@huawei.com,
iommu@lists.linux-foundation.org,
"David S . Miller" <davem@davemloft.net>,
linux-crypto@vger.kernel.org,
Philippe Ombredanne <pombredanne@nexb.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-accelerators@lists.ozlabs.org
Subject: Re: [RFCv2 PATCH 0/7] A General Accelerator Framework, WarpDrive
Date: Fri, 7 Sep 2018 18:55:45 +0100 [thread overview]
Message-ID: <404f0944-d514-b450-f743-89ae798ac694@arm.com> (raw)
In-Reply-To: <20180907165303.GA3519@redhat.com>
On 07/09/2018 17:53, Jerome Glisse wrote:
> So there is no reasons to do that under VFIO. Especialy as in your example
> it is not a real user space device driver, the userspace portion only knows
> about writting command into command buffer AFAICT.
>
> VFIO is for real userspace driver where interrupt, configurations, ... ie
> all the driver is handled in userspace. This means that the userspace have
> to be trusted as it could program the device to do DMA to anywhere (if
> IOMMU is disabled at boot which is still the default configuration in the
> kernel).
If the IOMMU is disabled (not exactly a kernel default by the way, I
think most IOMMU drivers enable it by default), your userspace driver
can't bypass DMA isolation by accident. It just won't be allowed to
access the device. VFIO requires an IOMMU unless the admin forces the
NOIOMMU mode with the "enable_unsafe_noiommu_mode" module parameter, and
the userspace explicitly asks for it with VFIO_NOIOMMU_IOMMU, which
taints the kernel. Not for production. A normal userspace driver that
uses VFIO can only do DMA to its own memory.
Thanks,
Jean
next prev parent reply other threads:[~2018-09-07 17:56 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-03 0:51 [RFCv2 PATCH 0/7] A General Accelerator Framework, WarpDrive Kenneth Lee
2018-09-03 0:51 ` [PATCH 1/7] vfio/sdmdev: Add documents for WarpDrive framework Kenneth Lee
2018-09-06 18:36 ` Randy Dunlap
2018-09-07 2:21 ` Kenneth Lee
2018-09-03 0:51 ` [PATCH 2/7] iommu: Add share domain interface in iommu for sdmdev Kenneth Lee
2018-09-03 0:52 ` [PATCH 3/7] vfio: add sdmdev support Kenneth Lee
2018-09-03 2:11 ` Randy Dunlap
2018-09-06 8:08 ` Kenneth Lee
2018-09-03 2:55 ` Lu Baolu
2018-09-06 9:01 ` Kenneth Lee
2018-09-04 15:31 ` [RFC PATCH] vfio: vfio_sdmdev_groups[] can be static kbuild test robot
2018-09-04 15:32 ` [PATCH 3/7] vfio: add sdmdev support kbuild test robot
2018-09-04 15:32 ` kbuild test robot
2018-09-05 7:27 ` Dan Carpenter
2018-09-03 0:52 ` [PATCH 4/7] crypto: add hisilicon Queue Manager driver Kenneth Lee
2018-09-03 2:15 ` Randy Dunlap
2018-09-06 9:08 ` Kenneth Lee
2018-09-03 0:52 ` [PATCH 5/7] crypto: Add Hisilicon Zip driver Kenneth Lee
2018-09-03 0:52 ` [PATCH 6/7] crypto: add sdmdev support to Hisilicon QM Kenneth Lee
2018-09-03 2:19 ` Randy Dunlap
2018-09-06 9:09 ` Kenneth Lee
2018-09-03 0:52 ` [PATCH 7/7] vfio/sdmdev: add user sample Kenneth Lee
2018-09-03 2:25 ` Randy Dunlap
2018-09-06 9:10 ` Kenneth Lee
2018-09-03 2:32 ` [RFCv2 PATCH 0/7] A General Accelerator Framework, WarpDrive Lu Baolu
2018-09-06 9:11 ` Kenneth Lee
2018-09-04 15:00 ` Jerome Glisse
2018-09-04 16:15 ` Alex Williamson
2018-09-06 9:45 ` Kenneth Lee
2018-09-06 13:31 ` Jerome Glisse
2018-09-07 4:01 ` Kenneth Lee
2018-09-07 16:53 ` Jerome Glisse
2018-09-07 17:55 ` Jean-Philippe Brucker [this message]
2018-09-07 18:04 ` Jerome Glisse
2018-09-10 3:28 ` Kenneth Lee
2018-09-10 14:54 ` Jerome Glisse
2018-09-11 2:42 ` Kenneth Lee
2018-09-11 3:33 ` Jerome Glisse
2018-09-11 6:40 ` Kenneth Lee
2018-09-11 13:40 ` Jerome Glisse
2018-09-13 8:32 ` Kenneth Lee
2018-09-13 14:51 ` Jerome Glisse
2018-09-14 3:12 ` Kenneth Lee
2018-09-14 14:05 ` Jerome Glisse
2018-09-14 6:50 ` Tian, Kevin
2018-09-14 13:05 ` Kenneth Lee
2018-09-14 14:13 ` Jerome Glisse
2018-09-17 1:42 ` Jerome Glisse
2018-09-17 8:39 ` Kenneth Lee
2018-09-17 12:37 ` Jerome Glisse
2018-09-18 6:00 ` Kenneth Lee
2018-09-18 13:03 ` Jerome Glisse
2018-09-20 5:55 ` Kenneth Lee
2018-09-20 14:23 ` Jerome Glisse
2018-09-21 10:05 ` Kenneth Lee
2018-09-21 10:03 ` Kenneth Lee
2018-09-21 14:52 ` Jerome Glisse
2018-09-25 5:55 ` Kenneth Lee
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