Re: [Qemu-devel] [PATCH 20/39] virtio-pci: convert to memory API

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

On Mon, Aug 01, 2011 at 12:35:44PM +0300, Avi Kivity wrote:
> On 08/01/2011 11:26 AM, Michael S. Tsirkin wrote:
> >>
> >>   static void virtio_write_config(PCIDevice *pci_dev, uint32_t address,
> >>                                   uint32_t val, int len)
> >>   {
> >>       VirtIOPCIProxy *proxy = DO_UPCAST(VirtIOPCIProxy, pci_dev, pci_dev);
> >>  +    VirtIODevice *vdev = proxy->vdev;
> >>
> >>       if (PCI_COMMAND == address) {
> >>           if (!(val&  PCI_COMMAND_MASTER)) {
> >>  @@ -525,6 +503,9 @@ static void virtio_write_config(PCIDevice *pci_dev, uint32_t address,
> >>               }
> >>           }
> >>       }
> >>  +    if (address == PCI_BASE_ADDRESS_0&&  vdev->config_len) {
> >>  +        vdev->get_config(vdev, vdev->config);
> >>  +    }
> >>
> >>       pci_default_write_config(pci_dev, address, val, len);
> >>       msix_write_config(pci_dev, address, val, len);
> >
> >I'm not really sure why did we get the config on map,
> >specifically - Anthony, do you know?
> >But if we want to do that, memory space enable might
> >be a better place. Or maybe we just want a callback on
> >map.
> 
> 
> Just because a memory region becomes visible to the cpu is no reason
> to have a callback.  From the device perspective, it can't tell that
> it happened.

BTW this is what qxl does, too, conceptually: on config writes, it peeks
at the bar to detect whether that got unmapped.

> -- 
> error compiling committee.c: too many arguments to function