Re: [Qemu-devel] Re: [patch 2/2] acpi_piix4: expose no_hotplug attribute via i/o port

[Marcelo Tosatti <mtosatti@redhat.com>]

On Mon, Jan 10, 2011 at 11:25:48PM +0200, Michael S. Tsirkin wrote:
> On Mon, Jan 10, 2011 at 04:55:03PM -0200, Marcelo Tosatti wrote:
> > Expose no_hotplug attribute via I/O port, so ACPI BIOS can indicate
> > removability status to guest OS.
> > 
> > An updated seabios is required to make use of this feature (seabios.git
> > commit ID 3c241edf3d7ef29c21).
> > 
> > Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
> > Tested-by: Gleb Natapov <gleb@redhat.com>
> > 
> > Index: qemu/hw/acpi_piix4.c
> > ===================================================================
> > --- qemu.orig/hw/acpi_piix4.c
> > +++ qemu/hw/acpi_piix4.c
> > @@ -37,6 +37,7 @@
> >  #define GPE_BASE 0xafe0
> >  #define PCI_BASE 0xae00
> >  #define PCI_EJ_BASE 0xae08
> > +#define PCI_RMV_BASE 0xae0c
> >  
> >  #define PIIX4_PCI_HOTPLUG_STATUS 2
> >  
> > @@ -73,6 +74,7 @@ typedef struct PIIX4PMState {
> >      /* for pci hotplug */
> >      struct gpe_regs gpe;
> >      struct pci_status pci0_status;
> > +    uint32_t pci0_hotplug_enable;
> >  } PIIX4PMState;
> >  
> >  static void piix4_acpi_system_hot_add_init(PCIBus *bus, PIIX4PMState *s);
> > @@ -322,6 +324,25 @@ static const VMStateDescription vmstate_
> >      }
> >  };
> >  
> > +static void piix4_update_hotplug(PIIX4PMState *s)
> > +{
> > +    PCIDevice *dev = &s->dev;
> > +    BusState *bus = qdev_get_parent_bus(&dev->qdev);
> > +    DeviceState *qdev, *next;
> > +
> > +    s->pci0_hotplug_enable = 0;
> > +
> > +    QLIST_FOREACH_SAFE(qdev, &bus->children, sibling, next) {
> > +        PCIDeviceInfo *info = container_of(qdev->info, PCIDeviceInfo, qdev);
> > +        PCIDevice *pdev = DO_UPCAST(PCIDevice, qdev, qdev);
> > +        int slot = PCI_SLOT(pdev->devfn);
> > +
> > +        if (!info->no_hotplug) {
> > +            s->pci0_hotplug_enable |= (1 << slot);
> > +        }
> > +    }
> > +}
> > +
> 
> So a slot starts as non-removable and becomes removable when you add a
> hotpluggable device?  Isn't this a bit strange?
> I would say all slots should be removable unless there's a
> non hotpluggable device there ...

Ugh, thats right, thanks.