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.
Hm...
static void spapr_phb_vfio_instance_init(Object *obj)
{
if (!qtest_enabled()) {
error_report("spapr-pci-vfio-host-bridge is deprecated");
}
}
I guess we can live with that :)
>
> Signed-off-by: Eduardo Habkost <ehabk...@redhat.com>
> ---
> Changes v1 (RFC) -> v2:
> * New commit message
> * Clarified comments
> Suggested-by: Halil Pasic <pa...@linux.vnet.ibm.com>
> * Moved variable declaration outside of loop
> Suggested-by: Cornelia Huck <cornelia.h...@de.ibm.com>
> ---
> hw/core/machine.c | 39 ++++++++++++++++++++++++++++++++++++---
> 1 file changed, 36 insertions(+), 3 deletions(-)
Reviewed-by: Cornelia Huck <cornelia.h...@de.ibm.com>
