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

["Chen, Tiejun" <tiejun.chen@xxxxxxxxx>]

On 2014/8/22 0:16, Konrad Rzeszutek Wilk wrote:
> 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
Fixed.

> > real vendor/device ids as the driver expect.
> Could you add a bit more description to this patch please? Explain
> the rationale, etc.
So rephrase as follows:

xen:i386:pc_piix: create isa bridge specific to IGD passthrough

Currently IGD drivers always need to access PCH by 1f.0, and
identify PCH type with its own real vendor/device ids. This type
value help driver initialize correctly.

> > Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>
> > ---
> >   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
Like the patch description, so what about this,

    /* Currently IGD drivers always need to access PCH by 1f.0, and
     * identify PCH type with its own real vendor/device ids.
     */

Thanks
Tiejun

> > +     */
> > +    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
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxx
> > http://lists.xen.org/xen-devel
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