Re: [Qemu-devel] [v5][PATCH 4/5] xen, gfx passthrough: create host bridge to passthrough

[Chen, Tiejun]

On 2014/6/25 14:24, Paolo Bonzini wrote:
> Il 25/06/2014 04:17, Tiejun Chen ha scritto:
> > +    if (xen_enabled() && xen_has_gfx_passthru) {
> > +        d = pci_create_simple(b, 0, TYPE_I440FX_XEN_PCI_DEVICE);
> > +        *pi440fx_state = I440FX_XEN_PCI_DEVICE(d);
> > +        pci_create_pch(b);
> > +    } else {
> > +        d = pci_create_simple(b, 0, TYPE_I440FX_PCI_DEVICE);
> > +        *pi440fx_state = I440FX_PCI_DEVICE(d);
> > +    }
>
> As mentioned in the review of v4, this should be a separate,
> Xen-specific machine.  pci_create_pch should not be called in generic PC
> code.

I track this path:

qemu_register_pc_machine(&xenfv_machine);
        |
        + .init = pc_xen_hvm_init,
                |
                + pc_init_pci(machine);
                        |
                        + pc_init1(machine, 1, 1);
                                |
                                + i440fx_init()

So how to separate this to specific to xen? Or you mean we need to 
create an new machine to address this scenario? But actually this is 
same as xenfv_machine except for these little codes.

If you don't like this involve other cases, we may drop this chunk of 
codes as a function to tweak with CONFIG_XEN. But this is not good as 
well since this is device feature, so kvm may need this one day.


Thanks
Tiejun