On Mon, 5 Dec 2016 16:42:00 +0100 Cornelia Huck <cornelia.h...@de.ibm.com> wrote:
> On Mon, 05 Dec 2016 16:21:22 +0100 > Greg Kurz <gr...@kaod.org> wrote: > > AFAIK, libvirt's XML doesn't know about modern/legacy modes for virtio > > devices. Early adopters of virtio 1.0 had to rely on the <qemu:commandline> > > tag to pass global properties to QEMU. This patch ensures that XML files > > used with older machine types remain valid with newer versions of QEMU. I recall some libvirt patches floating around for this legacy/modern stuff, but I don't know their status. > > > > FWIW I guess it could help to have this fix in 2.8, and also probably in > > 2.7.1. > > ...but I'm a bit worried about doing that change this late in the > cycle, as we may introduce subtle changes for other configurations. At > the very least, we should look over the existing backwards compat > properties (I'll look at those I'm familiar with). The s390x properties seem safe. For virtio-pci, the ability to override extra state might become problematic for modern devices. Although manually setting this property is probably a patholotical case...
