Re: [Qemu-devel] [Xen-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve 00:02.0 for INTEL IGD

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Fri, May 16, 2014 at 06:53:40PM +0800, Tiejun Chen wrote:
> Some VBIOSs and drivers assume the IGD BDF (bus:device:function) is
> always 00:02.0, so we need to reserves 00:02.0 for assigned IGD in

reserve

> guest.
> 
> Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
> Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
> ---
> v2:
> 
> * Use a common way patch #2 introduce to reserve PCI devfn.
> 
>  hw/pci-host/piix.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c
> index ffdc853..b6f49bd 100644
> --- a/hw/pci-host/piix.c
> +++ b/hw/pci-host/piix.c
> @@ -329,6 +329,14 @@ PCIBus *i440fx_init(PCII440FXState **pi440fx_state,
>      s = PCI_HOST_BRIDGE(dev);
>      b = pci_bus_new(dev, NULL, pci_address_space,
>                      address_space_io, 0, TYPE_PCI_BUS);
> +
> +    /*
> +     * Some video bioses and gfx drivers will assume the bdf of IGD is 00:02.0.
> +     * So user need to set it to 00:02.0 in Xen configure file explicitly,
> +     * otherwise IGD will fail to work.
> +     */
> +    pci_reserve_pci_devfn(b, PCI_DEVFN(2, 0));
> +

And we do this without checking whether PCI passthrough is done. Should
it be gated on that? Or is the reason you do it unconditionally because
you want to be able to hot-plug an GFX in?

>      s->bus = b;
>      object_property_add_child(qdev_get_machine(), "i440fx", OBJECT(dev), NULL);
>      qdev_init_nofail(dev);
> -- 
> 1.9.1
> 
> 
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