From: Joerg Roedel <joro@8bytes.org>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>,
Kevin Wolf <kwolf@redhat.com>, Wei Liu <wei.liu2@citrix.com>,
Andy Lutomirski <luto@kernel.org>,
qemu-block@nongnu.org,
Christian Borntraeger <borntraeger@de.ibm.com>,
Jason Wang <jasowang@redhat.com>,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
qemu-devel@nongnu.org, peterx@redhat.com,
linux-kernel@vger.kernel.org, Amit Shah <amit.shah@redhat.com>,
iommu@lists.linux-foundation.org,
Stefan Hajnoczi <stefanha@redhat.com>,
kvm@vger.kernel.org, cornelia.huck@de.ibm.com,
pbonzini@redhat.com, virtualization@lists.linux-foundation.org,
Anthony PERARD <anthony.perard@citrix.com>
Subject: Re: [PATCH V2 RFC] fixup! virtio: convert to use DMA api
Date: Wed, 27 Apr 2016 16:23:32 +0200 [thread overview]
Message-ID: <20160427142331.GH17926@8bytes.org> (raw)
In-Reply-To: <20160427153345-mutt-send-email-mst@redhat.com>
On Wed, Apr 27, 2016 at 04:37:04PM +0300, Michael S. Tsirkin wrote:
> One correction: it's a feature of the device in the system.
> There could be a mix of devices bypassing and not
> bypassing the IOMMU.
No, it really is not. A device can't chose to bypass the IOMMU. But the
IOMMU can chose to let the device bypass. So any fix here belongs
into the platform/iommu code too and not into some driver.
> Sounds good. And a way to detect appropriate devices could
> be by looking at the feature flag, perhaps?
Again, no! The way to detect that is to look into the iommu description
structures provided by the firmware. They provide everything necessary
to tell the iommu code which devices are not translated.
Joerg
next prev parent reply other threads:[~2016-04-27 14:23 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-21 13:43 [PATCH V2 RFC] fixup! virtio: convert to use DMA api Michael S. Tsirkin
2016-04-21 13:54 ` Wei Liu
2016-04-27 12:18 ` David Woodhouse
2016-04-27 13:37 ` Michael S. Tsirkin
2016-04-27 14:23 ` Joerg Roedel [this message]
2016-04-27 14:31 ` Andy Lutomirski
2016-04-27 14:38 ` Michael S. Tsirkin
2016-04-27 14:43 ` Andy Lutomirski
2016-04-27 14:54 ` Michael S. Tsirkin
2016-04-27 14:58 ` Joerg Roedel
2016-04-27 15:09 ` Michael S. Tsirkin
2016-04-27 15:10 ` Andy Lutomirski
2016-04-27 14:34 ` Michael S. Tsirkin
2016-04-27 14:56 ` Joerg Roedel
2016-04-27 15:05 ` Michael S. Tsirkin
2016-04-27 15:15 ` David Woodhouse
2016-04-27 18:17 ` Michael S. Tsirkin
2016-04-27 19:16 ` David Woodhouse
2016-04-28 14:34 ` Michael S. Tsirkin
2016-04-28 15:11 ` David Woodhouse
2016-04-28 15:37 ` Michael S. Tsirkin
2016-04-28 15:48 ` David Woodhouse
2016-05-01 10:37 ` Michael S. Tsirkin
2016-05-09 11:09 ` Paolo Bonzini
2016-04-21 14:56 ` Stefan Hajnoczi
2016-04-21 15:11 ` Michael S. Tsirkin
2016-04-22 9:33 ` Stefan Hajnoczi
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