Re: [Qemu-devel] [PATCH 2/9] pc: acpi: decribe bridge device as not hotpluggable

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Dec 09, 2014 at 12:45:27PM +0100, Igor Mammedov wrote:
> On Tue, 9 Dec 2014 12:34:02 +0200
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
> 
> > On Tue, Dec 09, 2014 at 11:27:16AM +0100, Igor Mammedov wrote:
> > > On Mon, 8 Dec 2014 21:13:25 +0200
> > > "Michael S. Tsirkin" <mst@redhat.com> wrote:
> > > 
> > > > On Mon, Dec 08, 2014 at 04:08:01PM +0000, Igor Mammedov wrote:
> > > > > when bridge hotplug is disabled, i.e. for machine
> > > > > types less then 2.0, bridge device was created as
> > > > > hotpluggable by mistake since commit 133a2da.
> > > > > 
> > > > > Fix it by just creating it as a present device.
> > > > > 
> > > > > Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> > > > 
> > > > What exactly is the problem here?
> > > > It seems that such bridge is hotpluggable, even though
> > > > e.g. windows guests lacks drivers to support this.
> > > before 133a2da slot with existing at startup bridge weren't
> > > marked as hotpluggable nor described in SSDT. But after
> > > 133a2da it's described as hotpluggable slot for compat
> > > machines (2.0 and lower) which doesn't match with original
> > > behavior.
> > > 
> > > Also Marcel mentioned that bridges could be hotpluggable
> > > but that they should not be hot-UNpluggable.
> > 
> > OK so is there some guest that's confused?
> > What's the bug?
> It allows to do eject on bridge when it shouldn't.

I'm not sure it shouldn't. Assuming guest supports SHPC, eject on such a
bridge might well work correctly.


> I don't know about consequences of it,
> it's better not to allow invalid action in the first place.
> 
> 
> > 
> > > > 
> > > > 
> > > > > ---
> > > > >  hw/i386/acpi-build.c | 2 +-
> > > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > > 
> > > > > diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> > > > > index b37a397..1fb92e5 100644
> > > > > --- a/hw/i386/acpi-build.c
> > > > > +++ b/hw/i386/acpi-build.c
> > > > > @@ -913,7 +913,7 @@ static void build_pci_bus_end(PCIBus *bus, void *bus_state)
> > > > >              }
> > > > >          }
> > > > >  
> > > > > -        if (!dc->hotpluggable || bridge_in_acpi) {
> > > > > +        if (!dc->hotpluggable || pc->is_bridge) {
> > > > >              clear_bit(slot, slot_hotplug_enable);
> > > > >          }
> > > > >      }
> > > > > -- 
> > > > > 1.8.3.1