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

[Anthony Liguori]

On 08/01/2011 05:23 AM, Michael S. Tsirkin wrote:
> 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.
>
> Well, the reason we have this logic here, I think, is
> to make sure it runs before the guest accesses
> the configuration with a write access.
>
> I'm not sure why we don't do this in the init
> callback - Anthony?

It could be done in init I think.  I can't recall why it didn't start 
that way initially.

Regards,

Anthony Liguori

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