From: "Michael S. Tsirkin" <mst@redhat.com>
To: Avi Kivity <avi@scylladb.com>
Cc: Alex Williamson <alex.williamson@redhat.com>,
avi@cloudius-systems.com, gleb@scylladb.com, corbet@lwn.net,
bruce.richardson@intel.com, linux-kernel@vger.kernel.org,
alexander.duyck@gmail.com, gleb@cloudius-systems.com,
stephen@networkplumber.org, vladz@cloudius-systems.com,
iommu@lists.linux-foundation.org, hjk@hansjkoch.de,
gregkh@linuxfoundation.org
Subject: Re: [RFC PATCH 2/2] vfio: Include no-iommu mode
Date: Sun, 11 Oct 2015 11:57:59 +0300 [thread overview]
Message-ID: <20151011115503-mutt-send-email-mst@redhat.com> (raw)
In-Reply-To: <561A19DE.8040302@scylladb.com>
On Sun, Oct 11, 2015 at 11:12:14AM +0300, Avi Kivity wrote:
> > Mixing no-iommu and secure VFIO is
> >also unsupported, as are any VFIO IOMMU backends other than the
> >vfio-noiommu backend. Furthermore, unsafe group files are relocated
> >to /dev/vfio-noiommu/. Upon successful loading in this mode, the
> >kernel is tainted due to the dummy IOMMU put in place. Unloading of
> >the module in this mode is also unsupported and will BUG due to the
> >lack of support for unregistering an IOMMU for a bus type.
>
> I did not see an API for detecting whether memory translation is provided or
> not. We can have the caller guess this by looking at the device name, or by
> requiring the user to specify this, but I think it's cleaner to provide
> programmatic access to this attribute.
It seems that caller can just check for VFIO_NOIOMMU_IOMMU.
Isn't this why it's there?
VFIO_IOMMU_MAP_DMA, VFIO_IOMMU_ENABLE and VFIO_IOMMU_DISABLE
will probably also fail ...
--
MST
next prev parent reply other threads:[~2015-10-11 8:58 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-09 18:40 [RFC PATCH 0/2] VFIO no-iommu Alex Williamson
2015-10-09 18:41 ` [RFC PATCH 1/2] vfio: Move vfio.c vfio_core.c Alex Williamson
2015-10-09 19:21 ` Greg KH
2015-10-09 18:41 ` [RFC PATCH 2/2] vfio: Include no-iommu mode Alex Williamson
2015-10-11 8:12 ` Avi Kivity
2015-10-11 8:57 ` Michael S. Tsirkin [this message]
2015-10-11 9:03 ` Avi Kivity
2015-10-11 9:19 ` Michael S. Tsirkin
2015-10-11 9:23 ` Gleb Natapov
2015-10-11 21:16 ` Alex Williamson
2015-10-12 15:56 ` Stephen Hemminger
2015-10-12 16:23 ` Alex Williamson
2015-10-12 16:31 ` Avi Kivity
2015-10-12 16:27 ` Michael S. Tsirkin
2015-10-12 17:46 ` Alex Williamson
2015-10-12 18:08 ` Alex Williamson
2015-10-11 17:29 ` [RFC PATCH 0/2] VFIO no-iommu Varun Sethi
2015-10-11 18:23 ` Alex Williamson
2015-10-11 18:28 ` Michael S. Tsirkin
2015-10-11 18:29 ` Michael S. Tsirkin
2015-10-11 19:25 ` Alex Williamson
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