Re: [Qemu-devel] [PATCH v2] vfio/igd: handle q35 machine type

[Alex Williamson <alex.williamson@redhat.com>]

On Fri,  4 Mar 2016 09:41:53 +0100
Gerd Hoffmann <kraxel@redhat.com> wrote:

> Basically skip the lpc quirks with -M q35.
> Applies on top of the vfio-igd patch series by alex.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  hw/vfio/pci-quirks.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/hw/vfio/pci-quirks.c b/hw/vfio/pci-quirks.c
> index 5828362..1757e3d 100644
> --- a/hw/vfio/pci-quirks.c
> +++ b/hw/vfio/pci-quirks.c
> @@ -12,6 +12,7 @@
>  
>  #include "qemu/osdep.h"
>  #include "hw/nvram/fw_cfg.h"
> +#include "hw/i386/ich9.h"
>  #include "pci.h"
>  #include "trace.h"
>  #include "qemu/range.h"
> @@ -1410,6 +1411,7 @@ int vfio_pci_igd_lpc_init(VFIOPCIDevice *vdev,
>                             struct vfio_region_info *region)
>  {
>      DeviceClass *dc = DEVICE_GET_CLASS(vdev);
> +    PCIBus *bus;
>      PCIDevice *lpc_bridge;
>      int ret;
>  
> @@ -1423,6 +1425,19 @@ int vfio_pci_igd_lpc_init(VFIOPCIDevice *vdev,
>  
>      dc->hotpluggable = false;
>  
> +    bus = pci_device_root_bus(&vdev->pdev);
> +    lpc_bridge = pci_find_device(bus, 0, PCI_DEVFN(0x1f, 0));
> +    if (lpc_bridge) {
> +        const char *type = object_get_typename(OBJECT(lpc_bridge));
> +        if (strcmp(type, TYPE_ICH9_LPC_DEVICE) == 0) {
> +            /*
> +             * q35 lpc present, leave it as-is.
> +             * linux kernel 4.5+ can deal with this.

What about anything older?  I assume we want to support current
distributions.  Based on this patch it seems like we also want to test
first if the lpc device is present, create it if not, then probably
copy host data into it.  Thanks,

Alex

> +             */
> +            return 0;
> +        }
> +    }
> +
>      lpc_bridge = pci_create_simple(pci_device_root_bus(&vdev->pdev),
>                                     PCI_DEVFN(0x1f, 0),
>                                     "vfio-pci-igd-lpc-bridge");