Re: [libvirt] [PATCH] qemu: fix command line building for iommu devices

On Mon, Oct 03, 2016 at 03:02:38PM +0200, Peter Krempa wrote: >On Mon, Oct 03, 2016 at 13:41:13 +0100, Daniel Berrange wrote: >> The intel-iommu device has existed since QEMU 2.2.0, but >> it was only possible to create it with -device since >> QEMU 2.7.0, thanks to: >> >> commit 621d983a1f9051f4cfc3f402569b46b77d8449fc >> Author: Marcel Apfelbaum <marcel(a)redhat.com&gt; >> Date: Mon Jun 27 18:38:34 2016 +0300 >> >> hw/iommu: enable iommu with -device >> >> Use the standard '-device intel-iommu' to create the IOMMU device. >> The legacy '-machine,iommu=on' can still be used. >> >> The libvirt capability check & command line formatting code >> is thus broken for all QEMU versions 2.2.0 -> 2.6.0 inclusive. >> >> This fixes it to use iommu=on instead. >> >> Signed-off-by: Daniel P. Berrange <berrange(a)redhat.com&gt; >> --- > >Is there any value to make it work with older versions rather than just >clearing it completely on the versions that don't support it with >-device? > I had one question as well. Are those invocations migration-compatible? I can't try it right now, so I figured asking would be faster than preparing two machines with different QEMU versions =) If they are not, then I would just say clear it.

Martin