From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH RFC] fixup! virtio: convert to use DMA api
Date: Tue, 19 Apr 2016 20:49:48 +0300
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Cc: 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>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	peterx@redhat.com,
	"qemu-devel@nongnu.org Developers" <qemu-devel@nongnu.org>,
	Amit Shah <amit.shah@redhat.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>, kvm list <kvm@vger.kernel.org>,
	Cornelia Huck <cornelia.huck@de.ibm.com>,
	Paolo Bonzini <pbonzini@redhat.com>, Andy Lutomirski <luto@amacapital.net>,
	Linux Virtualization <virtualization@lists.linux-foundation.org>
To: David Woodhouse <dwmw2@infradead.org>
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On Tue, Apr 19, 2016 at 12:26:44PM -0400, David Woodhouse wrote:
> On Tue, 2016-04-19 at 19:20 +0300, Michael S. Tsirkin wrote:
> >=20
> > > I thought that PLATFORM served that purpose.=A0 Woudn't the host
> > > advertise PLATFORM support and, if the guest doesn't ack it, the ho=
st
> > > device would skip translation?=A0 Or is that problematic for vfio?
> >=20
> > Exactly that's problematic for security.
> > You can't allow guest driver to decide whether device skips security.
>=20
> Right. Because fundamentally, this *isn't* a property of the endpoint
> device, and doesn't live in virtio itself.
>=20
> It's a property of the platform IOMMU, and lives there.

It's a property of the hypervisor virtio implementation, and lives there.

--=20
MST