On Wed, 14 Dec 2016 15:04:27 -0200 Eduardo Habkost <ehabk...@redhat.com> wrote:
> On Wed, Dec 14, 2016 at 04:42:14PM +0100, Greg Kurz wrote: > > On Mon, 12 Dec 2016 18:49:05 -0200 > > Eduardo Habkost <ehabk...@redhat.com> wrote: > > > > > Original problem description by Greg Kurz: > > > > > > > Since commit "9a4c0e220d8a hw/virtio-pci: fix virtio > > > > behaviour", passing -device virtio-blk-pci.disable-modern=off > > > > has no effect on 2.6 machine types because the internal > > > > virtio-pci.disable-modern=on compat property always prevail. > > > > > > The same bug also affects other abstract type names mentioned on > > > compat_props by machine-types: apic-common, i386-cpu, pci-device, > > > powerpc64-cpu, s390-skeys, spapr-pci-host-bridge, usb-device, > > > virtio-pci, x86_64-cpu. > > > > > > The right fix for this problem is to make sure compat_props and > > > -global options are always applied in the order they are > > > registered, instead of reordering them based on the type > > > hierarchy. But changing the ordering rules of -global is risky > > > and might break existing configurations, so we shouldn't do that > > > on a stable branch. > > > > > > This is a temporary hack that will work around the bug when > > > registering compat_props properties: if we find an abstract class > > > on compat_props, register properties for all its non-abstract > > > subtypes instead. This will make sure -global won't be overridden > > > by compat_props, while keeping the existing ordering rules on > > > -global options. > > > > > > Note that there's one case that won't be fixed by this hack: > > > "-global spapr-pci-vfio-host-bridge.<option>=<value>" won't be > > > able to override compat_props, because spapr-pci-host-bridge is > > > not an abstract class. > > > > > > Signed-off-by: Eduardo Habkost <ehabk...@redhat.com> > > > --- > > > > This patch had 3 r-b. Is there any good reason to hold > > it up to 2.8.1 ? > > Applying it today would mean delaying the 2.8.0 release, and the > bug is not serious enough to justify that. > IIUC there will be a v2.8.0-rc4 because we want this patch in 2.8: [PATCH v3] virtio-pci: Fix cross-version migration with older machines From IRC: <stefanha> mcoquelin: Once Michael Tsirkin has reviewed your patch I'll merge it and tag v2.8.0-rc4 (today or tomorrow?). The QEMU 2.8 release will be next Tuesday.
