Re: [Qemu-devel] [Xen-devel] [PATCH 2/2] xen:i386:pc_piix: create isa bridge specific to IGD passthrough

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

On Thu, Aug 21, 2014 at 09:28:28AM +0800, Tiejun Chen wrote:
> Currenjly this ISA bridge should be fixed at 1f.0, and pass the

Currently

> real vendor/device ids as the driver expect.

Could you add a bit more description to this patch please? Explain
the rationale, etc.
> 
> Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
> ---
>  hw/i386/pc_piix.c | 24 +++++++++++++++++++++++-
>  1 file changed, 23 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index 7710724..b131fa3 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -50,7 +50,8 @@
>  #include "cpu.h"
>  #include "qemu/error-report.h"
>  #ifdef CONFIG_XEN
> -#  include <xen/hvm/hvm_info_table.h>
> +#include <xen/hvm/hvm_info_table.h>
> +#include <hw/xen/xen-host-pci-device.h>
>  #endif
>  
>  #define MAX_IDE_BUS 2
> @@ -463,6 +464,26 @@ static void pc_xen_hvm_init(MachineState *machine)
>      }
>  }
>  
> +static void xen_igd_passthrough_isa_bridge_create(PCIBus *bus)
> +{
> +    struct PCIDevice *dev;
> +    XenHostPCIDevice hdev;
> +    int r = 0;
> +
> +    /* This shoudl be fixed at 1f.0 then pass vendor/device ids.

should

However I would remove the comment as it does not add anything extra
to the function. It is pretty clear what it is doing.

What would help is if you said:

Must be fixed at 1f.0 because .. bla blah

> +     */
> +    dev = pci_create_simple(bus, PCI_DEVFN(0x1f, 0),
> +                            "xen-igd-passthrough-isa-bridge");
> +    if (dev) {
> +        r = xen_host_pci_device_get(&hdev, 0, 0, PCI_DEVFN(0x1f, 0), 0);
> +        if (!r) {
> +            pci_config_set_vendor_id(dev->config, hdev.vendor_id);
> +            pci_config_set_device_id(dev->config, hdev.device_id);
> +        } else
> +            fprintf(stderr, "xen set xen-igd-passthrough-isa-bridge failed\n");
> +    }
> +}
> +
>  static void xen_igd_passthrough_pc_hvm_init(MachineState *machine)
>  {
>      PCIBus *bus;
> @@ -472,6 +493,7 @@ static void xen_igd_passthrough_pc_hvm_init(MachineState *machine)
>      bus = pci_find_primary_bus();
>      if (bus != NULL) {
>          pci_create_simple(bus, -1, "xen-platform");
> +        xen_igd_passthrough_isa_bridge_create(bus);
>      }
>  }
>  #endif
> -- 
> 1.9.1
> 
> 
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