> > > > Cc: [3][4][5][7]
xen-users@xxxxxxxxxxxxxxxxxxx
> > > > Subject: Re: [Xen-users] PCI Passthrough without
> VT-d
> > > >
> > > > On Fri, Feb 26, 2010 at 11:29:22PM +0100, Jan
> ?eš?ut
> > wrote:
> > > > > Â Â As I read XEN supports assigning a pci
> device to an
> > > unprivileged
> > > > domain
> > > > > Â Â without hardware supporting it. Has anyone
> already
> > tried
> > > it? Are
> > > > there any
> > > > > Â Â security risks? If I understand correctly
> how PCI
> > > passthrough
> > > > works the
> > > > > Â Â performance should be the same as using
> the pci
> > device in
> > > native
> > > > mode. Is
> > > > > Â Â it so? I have a PCI video card which would
> like to
> > use
> > > inside a
> > > > VM running
> > > > > Â Â Windows XP.
> > > > >
> > > >
> > > > Xen supports PCI passthrough to _PV_
> (paravirtual) guests
> > without
> > > VT-d,
> > > > and has actually supported that for years. There
> are some
> > > potential
> > > > security
> > > > risks in this, since the PV guest gets full DMA
> control of
> > the
> > > PCI
> > > > device
> > > > and could use it for malicious purposes.
> > > >
> > > > Xen PCI passthrough to HVM guests (=Windows)
> requires VT-d
> > > hardware
> > > > support.
> > > >
> > > > Also, PCI passthrough of a VGA/video card is not
> as simple
> > as PCI
> > > > passthrough
> > > > of other cards (nic, disk controller, usb
> controller).
> > > >
> > > > VGA has lots of legacy stuff related to it, some
> memory
> > ranges,
> > > IO
> > > > ports, VGA BIOS,
> > > > etc that have to be 'passed through' aswell, and
> emulated.
> > > >
> > > > Xen 4.0.0 will have PCI passthrough support of
> primary VGA
> > > adapters, but
> > > > it requires
> > > > VT-d support as stated already earlier.
> > > >
> > > > -- Pasi
> > > >
> > > > ps. There is actually a hack/patch available that
> allows
> > PCI
> > > passthrough
> > > > to HVM guest
> > > > without VT-d, but that only works for the _first_
> started
> > HVM
> > > guest, and
> > > > it's experimental
> > > > and not supported in any way. iirc the patch is
> available
> > in
> > > xen-devel
> > > > archives.
> > > >
> > > > _______________________________________________
> > > > Xen-users mailing list